Publications by authors named "Kyusup Lee"

27 Publications

  • Page 1 of 1

Multivessel versus IRA-only PCI in patients with NSTEMI and severe left ventricular systolic dysfunction.

PLoS One 2021 13;16(10):e0258525. Epub 2021 Oct 13.

Korea Institute of Toxicology, Daejeon, Republic of Korea.

Background: A substantial number of patients presenting with non-ST-elevation myocardial infarction (NSTEMI) and multivessel disease (MVD) have severe left ventricular systolic dysfunction (LVSD) (left ventricular ejection fraction (LVEF) less than 35%). But data are lacking regarding optimal percutaneous coronary intervention (PCI) strategy for these patients. The aim of this study was to compare the long-term outcomes of IRA (infarct-related artery)-only and multivessel PCI in patients with NSTEMI and MVD complicated by severe LVSD.

Methods: Among 13,104 patients enrolled in the PCI registry from November 2011 to December 2015, patients with NSTEMI and MVD with severe LVSD who underwent successful PCI were screened. The primary outcome was 3-year major adverse cardiovascular events (MACEs), defined as all-cause death, any myocardial infarction, stroke, and any revascularization.

Results: Overall, 228 patients were treated with IRA-only PCI (n = 104) or MV-PCI (n = 124). The MACE risk was significantly lower in the MV-PCI group than in the IRA-only PCI group (35.5% vs. 54.8%; hazard ratio [HR] 0.561; 95% confidence interval [CI] 0.378-0.832; p = 0.04). This result was mainly driven by a significantly lower risk of all-cause death (23.4% vs. 41.4%; hazard ratio [HR] 0.503; 95% confidence interval [CI] 0.314-0.806; p = 0.004). The results were consistent after multivariate regression, propensity-score matching, and inverse probability weighting to adjust for baseline differences.

Conclusions: Among patients with NSTEMI and MVD complicated with severe LVSD, multivessel PCI was associated with a significantly lower MACE risk. The findings may provide valuable information to physicians who are involved in decision-making for these patients.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0258525PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8513855PMC
October 2021

Percutaneous Transcatheter Closure of Iatrogenic Aorto-right Atrial Fistula Using the Amplatzer Duct Occluder.

Korean Circ J 2021 Sep;51(9):789-791

Department of Cardiology, St. Vincent's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.

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http://dx.doi.org/10.4070/kcj.2021.0135DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8424451PMC
September 2021

Effect of smoking on clinical outcomes in patients receiving rotational atherectomy in calcified coronary lesions: from the ROCK Registry, South Korea.

Ann Saudi Med 2021 Jul-Aug;41(4):191-197. Epub 2021 Aug 22.

From the Department of Internal Medicine, Wonkwang University Hospital, Iksan, Jeollabuk-do, South Korea.

Background: Tobacco smoking and its harmful health effects also increase economic burdens globally. Surprisingly, despite the detrimental health consequences of smoking, some studies have shown better survival among smokers compared with non-smokers, a phenomenon called "smoker's paradox". However, the impact of smoking status on clinical outcomes in severe calcified coronary artery disease (CAD) patients has yet to be reported.

Objectives: Investigate the impact of smoking on clinical outcomes in calcified CAD receiving rotational atherectomy (RA).

Design: Retrospective review of medical records.

Setting: Multicenter registry in South Korea.

Patients And Methods: This multicenter registry included consecutive patients with calcified CAD who underwent RA at nine tertiary centers in Korea between January 2010 and October 2019.

Main Outcome Measures: Target-vessel failure (TVF) which included the composite of cardiac death, target-vessel myocardial infarction (TVMI), and target-vessel revascularization (TVR).

Sample Size: 583 lesions in 540 patients followed for a median of 16.1 months.

Results: Lesions were divided into two groups: non-smokers (n=472, 81.0%) and smokers (n=111, 19.0%). TVF in the smoker group was significantly more frequent than in non-smoker group (log rank =.016). The inverse probability of treatment weighting analysis also showed that smoking was significantly associated with a higher incidence of the primary outcome (HR: 1.617; 95% CI: 1.127-2.320; =.009), cardiac death (HR 1.912; 95% CI: 1.105-3.311; =.021), myocardial infarction (HR: 3.914; 95% CI: 1.884-8.132; <.001), TVMI (HR: 3.234; 95% CI: 1.130-9.258; =.029), and TVR (HR: 1.661; 95% CI: 1.043-2.643; =.032). However, any bleeding was significantly observed less in the smokers.

Conclusion: Smoking is significantly associated with adverse clinical outcomes in CAD patients requiring RA.

Limitations: Retrospective design.

Conflicts Of Interest: None.
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http://dx.doi.org/10.5144/0256-4947.2021.191DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8380281PMC
September 2021

Clinical Outcome of Rotational Atherectomy in Calcified Lesions in Korea-ROCK Registry.

Medicina (Kaunas) 2021 Jul 7;57(7). Epub 2021 Jul 7.

Department of Cardiology, St. Vincent's Hospital, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea.

: Data is still limited regarding clinical outcomes of rotational atherectomy (RA) after percutaneous coronary intervention. We sought to evaluate clinical outcomes of RA. This multi-center registry enrolled patients who underwent RA during PCI from nine tertiary centers in Korea between January 2010 and October 2019. The primary endpoint was target-vessel failure (TVF; the composite outcome of cardiac death, target-vessel spontaneous myocardial infarction, or target-vessel revascularization). : Of 540 patients (583 lesions), the mean patient age was 71.4 ± 0.4 years, 323 patients (59.8%) were men, and 305 patients (56.5%) had diabetes mellitus. Technical success rate was 96.4%. In-hospital major adverse cerebral and cardiac events occurred in 63 cases (10.8%). At 1.5 years, 72 (16.0%) of TVFs were occurred. We evaluated independent predictors of TVF, which included current smoker (hazard ratio (HR), 1.92; 95% confidence interval (CI), 1.17-3.16; = 0.01), chronic renal disease (HR, 1.87; 95% CI, 1.14-3.08; = 0.013), history of cerebrovascular attack (HR, 2.14; 95% CI, 1.24-3.68; = 0.006), left ventricle ejection fraction (HR, 0.98; 95% CI, 0.97-0.999; = 0.037), and left main disease (HR, 1.94; 95% CI, 1.11-3.37; = 0.019). From this registry, we demonstrated acceptable success rates, in-hospital and mid-term clinical outcomes of RA in the DES era.
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http://dx.doi.org/10.3390/medicina57070694DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8303478PMC
July 2021

Impact of chronic total occlusion lesions on clinical outcomes in patients receiving rotational atherectomy: results from the ROCK registry.

Heart Vessels 2021 Nov 10;36(11):1617-1625. Epub 2021 Apr 10.

Division of Cardiology, Department of Internal Medicine, Sejong General Hospital, Bucheon, Korea.

The aim of this study was to investigate the impact of chronic total occlusion (CTO) on clinical outcomes in patients with calcified coronary lesions receiving rotational atherectomy (RA). This multi-center registry enrolled consecutive patients with calcified coronary artery disease who underwent RA during percutaneous coronary intervention (PCI) from 9 tertiary centers in Korea between January 2010 and October 2019. The primary outcome was target-vessel failure (TVF) which included the composite of cardiac death, target-vessel myocardial infarction (TVMI), and target-vessel revascularization (TVR). A total of 583 lesions were enrolled in this registry and classified as CTO (n = 42 lesions, 7.2%) and non-CTO (n = 541 lesions, 92.8%). The CTO group consisted of younger patients who were more likely to have a history of previous percutaneous coronary intervention or coronary artery bypass graft surgery. The incidence of the primary outcome was 14.1% and 16.7% for the non-CTO group and CTO group, respectively. The primary outcomes observed in the two groups were not significantly different (log-rank p = 0.736). The 18-month clinical outcomes of the CTO group were comparable to those of the non-CTO group in multivariate analysis. About 7% of patients requiring RA have CTO lesions and these patients experience similar clinical outcomes compared with those having non-CTO lesions. Use of RA for CTO lesions was safe despite higher procedural complexity.
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http://dx.doi.org/10.1007/s00380-021-01849-4DOI Listing
November 2021

Clinical outcomes of post-stent intravascular ultrasound examination for chronic total occlusion intervention with drug-eluting stents.

EuroIntervention 2021 Oct 1;17(8):e639-e646. Epub 2021 Oct 1.

Division of Cardiology, Department of Internal Medicine, Eunpyeong St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.

Background: Few studies have evaluated intravascular ultrasound (IVUS) use in chronic total occlusion (CTO) percutaneous coronary intervention (PCI).

Aims: In CTO-PCI, we aimed to (1) evaluate the clinical benefits of performing post-stent IVUS in preventing adverse clinical events, and (2) identify IVUS parameters and cut-off values for prediction of target lesion revascularisation (TLR)/reocclusion.

Methods: A total of 1,077 patients with 1,077 CTO lesions treated with drug-eluting stents (DES) were included. Clinical outcomes during a median follow-up of 6.3 years were compared between subjects with and those without post-stent IVUS using the inverse probability weighting method.

Results: Of 1,077 patients, post-stent IVUS was performed in 838 (77.8%) cases while in the remaining 239 (22.2%) cases it was not. In the weighted population, the risk of TLR/reocclusion was significantly lower in subjects with post-stent IVUS (9.6% vs 18.9%, hazard ratio [HR] 0.54, 95% confidence interval [CI]: 0.34-0.86, p=0.01), compared with those without post-stent IVUS. Cox regression analysis showed that minimal stent area (MSA) measured by IVUS was the only parameter independently associated with TLR/reocclusion (HR 0.78, 95% CI: 0.64-0.95; p=0.01) and the optimal MSA cut-off value was 4.9 mm2 for prediction of TLR/reocclusion (area under the curve=0.632, p=0.001).

Conclusions: In CTO-PCI with DES, post-stent IVUS evaluation was associated with a lower risk of TLR/reocclusion. The final MSA was independently associated with TLR/reocclusion with a cut-off value of 4.9 mm2.
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http://dx.doi.org/10.4244/EIJ-D-20-00941DOI Listing
October 2021

Gender differences in clinical outcomes of acute myocardial infarction undergoing percutaneous coronary intervention: insights from the KAMIR-NIH Registry.

J Geriatr Cardiol 2020 Nov;17(11):680-693

Division of Cardiology, Daejeon St. Mary's hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea.

Background: There are numerous but conflicting data regarding gender differences in outcomes following percutaneous coronary intervention (PCI). Furthermore, gender differences in clinical outcomes with acute myocardial infarction (AMI) following PCI in Asian population remain uncertain because of the under-representation of Asian in previous trials.

Methods: A total of 13, 104 AMI patients from Korea Acute Myocardial Infarction Registry-National Institute of Health (KAMIR-NIH) between November 2011 and December 2015 were classified into male ( = 8021, 75.9%) and female ( = 2547, 24.1%). We compared the demographic, clinical and angiographic characteristics, 30-days and 1-year major adverse cardiac and cerebrovascular events (MACCE) in women with those in men after AMI by using propensity score (PS) matching.

Results: Compared with men, women were older, had more comorbidities and more often presented with non-ST segment elevation myocardial infarction (NSTEMI) and reduced left ventricular systolic function. Over the median follow-up of 363 days, gender differences in both 30-days and 1-year MACCE as well as thrombolysis in myocardial infarction minor bleeding risk were not observed in the PS matched population (30-days MACCE: 5.3% . 4.7%, log-rank = 0.494, HR = 1.126, 95% CI: 0.800-1.585; 1-year MACCE: 9.3% . 9.0%, log-rank = 0.803, HR = 1.032, 95% CI: 0.802-1.328; TIMI minor bleeding: 4.9% . 3.9%, log-rank = 0.215, HR = 1.255, 95% CI: 0.869-1.814).

Conclusions: Among Korean AMI population undergoing contemporary PCI, women, as compared with men, had different clinical and angiographic characteristics but showed similar 30-days and 1-year clinical outcomes. The risk of bleeding after PCI was comparable between men and women during one-year follow up.
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http://dx.doi.org/10.11909/j.issn.1671-5411.2020.11.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7729180PMC
November 2020

Fate of lumen size in distal coronary segment following successful chronic total occlusion recanalization.

J Cardiol 2021 01 26;77(1):65-71. Epub 2020 Oct 26.

Division of Cardiology, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.

Background: Restoration of anterograde blood flow leads to alterations in vascular wall stress that may influence lumen size distal to chronic total occlusion (CTO) lesions. We sought to assess changes in lumen diameter of segments distal to the stent segment of successfully recanalized CTO.

Methods: We analyzed 507 consecutive CTO cases with stent implantation that underwent follow-up angiography at a single high-volume center (mean follow-up of 13.5 months). Segments ≤40 mm distal to the stent edge were analyzed using quantitative coronary angiography.

Results: At follow-up, lumen diameters significantly increased; diameter changes of 0.26 ± 0.47 (percent diameter change of 18.2%) at 5 mm distal, mean lumen diameter changes of 0.23 ± 0.35 (14.3%) and minimal lumen diameter changes of 0.22 ± 0.80 (24.7%) (all p < 0.001). Lumen enlargement was similar between visually shrunken and stenosed vessels (degree of stenosis ≥20% with luminal irregularities) distal to stents; 5 mm distal (0.32 ± 0.48 vs. 0.30 ± 0.48, p = 0.76), mean lumen diameter changes (0.26 ± 0.37mm vs. 0.26±0.33 mm, p = 0.94), minimal lumen diameter changes (0.28 ± 0.43 mm vs. 0.22 ± 1.30 mm, p = 0.48). There was no association between degree of in-stent narrowing and changes in distal lumen diameter (Spearman r = -0.02, p = 0.59). Multivariate logistic regression for the predictors of greater lumen enlargement indicated that patients with left ventricle dysfunction (ejection fraction ≤45%) had greater enlargement [odds ratio (OR): 2.53, 95% confidence interval (CI): 1.23-5.23, p = 0.01]. Conversely, a low hematocrit (male <40%, and female <35%) was associated with attenuated lumen enlargement (OR: 0.68 95% CI: 0.47-0.98; p = 0.04).

Conclusions: Lumen diameter distal to CTO lesions significantly increased following successful revascularization, regardless of diseased status of the distal bed or degree of in-stent narrowing. These findings implicate appropriate determination of stent size, stent coverage length, as well as management strategies of distal vessels.
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http://dx.doi.org/10.1016/j.jjcc.2020.07.011DOI Listing
January 2021

Interplay of reactive interference and crowding effects in the diffusion-influenced reaction kinetics.

J Chem Phys 2020 Jul;153(4):044129

Department of Chemistry, Seoul National University, Seoul 151-747, South Korea.

We investigate the interplay of reactive interference and crowding effects in the irreversible diffusion-influenced bimolecular reactions of the type A+B→P+B by using the Brownian dynamics simulation method. It is known that the presence of nonreactive crowding agents retards the reaction rate when the volume fraction of the crowding agents is large enough. On the other hand, a high concentration of B is known to increase the reaction rate more than expected from the mass action law, although the B's may also act as crowders. Therefore, it would be interesting to see which effect dominates when the number density of B as well as the number density of the crowders increases. We will present an approximate theory that provides a reasonable account for the Brownian dynamics simulation results.
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http://dx.doi.org/10.1063/5.0016269DOI Listing
July 2020

Long-Term (10-Year) Outcomes of Stenting or Bypass Surgery for Left Main Coronary Artery Disease in Patients With and Without Diabetes Mellitus.

J Am Heart Assoc 2020 04 20;9(8):e015372. Epub 2020 Apr 20.

Division of Cardiology Asan Medical Center University of Ulsan College of Medicine Seoul Korea.

Background Data are still limited regarding whether there are differential long-term outcomes after percutaneous coronary intervention versus coronary artery bypass grafting (CABG) for left main coronary artery disease with or without diabetes mellitus (DM). Methods and Results Using the 10-year data from the MAIN-COMPARE (Revascularization for Unprotected Left Main Coronary Artery Stenosis: Comparison of Percutaneous Coronary Angioplasty Versus Surgical Revascularization) registry, we sought to examine the effect of DM on comparative outcomes after percutaneous coronary intervention or CABG in patients with unprotected left main coronary artery disease. The outcomes of interest were all-cause mortality; a composite of death, Q-wave myocardial infarction, or stroke; and target-vessel revascularization. The primary adjusted analyses were performed with the use of propensity scores and inverse-probability weighting. Of 2240 patients with left main coronary artery revascularization, 722 (32%) had DM. In the overall population, the adjusted 10-year risks of death and composite outcome were similar between percutaneous coronary intervention and CABG, irrespective of DM status (: 0.41, mortality; 0.40, composite outcome). However, in the cohort of bare-metal stents and concurrent CABG, we observed differential outcomes after stenting and CABG by DM status (: 0.09, mortality; 0.04, composite outcome), favoring CABG in patients with DM. In the cohort of drug-eluting stents and concurrent CABG, the better effect of CABG over stenting was narrowed in patients with DM without a significant interaction (: 0.63, mortality; 0.47, composite outcome). Conclusions In this cohort of patients with longest follow-up who underwent left main coronary artery revascularization, the clinical impact of DM favoring CABG over percutaneous coronary intervention has diminished over time from the bare-metal stent to the drug-eluting stent era. Registration URL: http://www.clini​caltr​ials.gov. Unique identifier: NCT02791412.
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http://dx.doi.org/10.1161/JAHA.119.015372DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7428513PMC
April 2020

Green's function of the Smoluchowski equation with reaction sink: Application to geminate and bulk recombination reactions.

J Chem Phys 2020 Apr;152(13):134102

Department of Chemistry, Seoul National University, Seoul 08826, South Korea.

By applying a recently developed solution method for the Fredholm integral equation of the second kind, we obtain an expression for Green's function of the Smoluchowski equation with a reaction sink. The result is applied to obtain accurate analytical expressions for the time-dependent survival probability of a geminate reactant pair and the rate coefficient of the bulk recombination between reactants undergoing diffusive motions under strong Coulomb interactions. The effects of both repulsive and attractive interactions are considered, and the results are compared with the numerical results obtained by solving the equation for the survival probability and the nonequilibrium pair correlation function. It is shown that the solutions are accurate enough for most reasonable parameter values.
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http://dx.doi.org/10.1063/1.5144269DOI Listing
April 2020

Anisotropic Picosecond Spin-Photocurrent from Weyl Semimetal WTe.

ACS Nano 2020 Mar 16;14(3):3539-3545. Epub 2020 Mar 16.

Department of Electrical and Computer Engineering and NUSNNI, National University of Singapore, 117576, Singapore.

The generation and detection of ultrafast spin current, preferably reaching a frequency up to terahertz, is the core of spintronics. Studies have shown that the Weyl semimetal WTe is of great potential in generating spin currents. However, the prior studies have been limited to the static measurements with the in-plane spin orientation. In this work, we demonstrate a picosecond spin-photocurrent in a Td-WTe thin film via a terahertz time domain spectroscopy with a circularly polarized laser excitation. The anisotropic dependence of the circular photogalvanic effect (CPGE) in the terahertz emission reveals that the picosecond spin-photocurrent is generated along the rotational asymmetry -axis. Notably, the generated spins are aligned along the out-of-plane direction under the light normally incident to the film surface, which provides an efficient means to manipulate magnetic devices with perpendicular magnetic anisotropy. A spin-splitting band induced by intrinsic inversion symmetry breaking enables the manipulation of a spin current by modulating the helicity of the laser excitation. Moreover, CPGE nearly vanishes at a transition temperature of ∼175 K due to the carrier compensation. Our work provides an insight into the dynamic behavior of the anisotropic spin-photocurrent of Td-WTe in terahertz frequencies and shows a great potential for the future development of terahertz-spintronic devices with Weyl semimetals.
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http://dx.doi.org/10.1021/acsnano.9b09828DOI Listing
March 2020

Clinical outcomes after percutaneous coronary intervention for in-stent chronic total occlusion.

EuroIntervention 2020 Aug 7;16(6):e472-e479. Epub 2020 Aug 7.

Division of Cardiology, Chungnam National University Hospital, Chungnam National University School of Medicine, Daejeon, South Korea.

Aims: The aim of this study was to compare percutaneous coronary intervention (PCI) outcomes in relation to stent optimisation profiles between in-stent chronic total occlusions (CTOs) and de novo CTOs.

Methods And Results: We evaluated 1,516 consecutive patients who underwent PCI for 147 in-stent CTOs (9.3%) and 1,439 de novo CTOs between 2007 and 2018. The primary endpoint was target vessel failure (TVF) consisting of a composite of cardiac death, target vessel-related myocardial infarction, or target vessel revascularisation. The final post-stenting intravascular ultrasound (IVUS) images were analysed. Target lesion complexity reflected by the Japanese CTO score was similar, albeit calcification was more prevalent in de novo CTOs, whereas occlusion length >20 mm was more frequent in in-stent CTOs. The technical success (88.4% vs 87.5%, p=0.84) and in-hospital adverse event (1.4% vs 3.6%, p=0.26) rates were similar between CTO types. Among those who received drug-eluting stents, the five-year TVF (11.0% vs 10.7%, p=0.99) and target vessel revascularisation (4.2% vs 3.7%, p=0.81) rates were similar between groups. Total stent length, minimum stent area (5.4±1.8 vs 5.5±1.8 mm2, p=0.77), and maximal plaque burden of the reference segments were largely comparable between groups.

Conclusions: In-stent CTO PCI with drug-eluting stents optimised by IVUS guidance offers as acceptable long-term clinical results as those achieved in de novo CTOs.
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http://dx.doi.org/10.4244/EIJ-D-19-00650DOI Listing
August 2020

Magnetization switching by magnon-mediated spin torque through an antiferromagnetic insulator.

Science 2019 11;366(6469):1125-1128

Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore.

Widespread applications of magnetic devices require an efficient means to manipulate the local magnetization. One mechanism is the electrical spin-transfer torque associated with electron-mediated spin currents; however, this suffers from substantial energy dissipation caused by Joule heating. We experimentally demonstrated an alternative approach based on magnon currents and achieved magnon-torque-induced magnetization switching in BiSe/antiferromagnetic insulator NiO/ferromagnet devices at room temperature. The magnon currents carry spin angular momentum efficiently without involving moving electrons through a 25-nanometer-thick NiO layer. The magnon torque is sufficient to control the magnetization, which is comparable with previously observed electrical spin torque ratios. This research, which is relevant to the energy-efficient control of spintronic devices, will invigorate magnon-based memory and logic devices.
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http://dx.doi.org/10.1126/science.aav8076DOI Listing
November 2019

Clinical Situations Associated with Inappropriately Large Regurgitant Volumes in the Assessment of Mitral Regurgitation Severity Using the Proximal Flow Convergence Method in Patients with Chordae Rupture.

J Am Soc Echocardiogr 2020 01 23;33(1):64-71. Epub 2019 Oct 23.

Division of Cardiology, Asan Medical Center Heart Institute, University of Ulsan College of Medicine, Seoul, Republic of Korea. Electronic address:

Background: Regurgitant volume (RVol) calculated using the proximal flow convergence method (proximal isovelocity surface area [PISA]) has been accepted as a key quantitative parameter for the diagnosis of and clinical decision-making with regard to severe mitral regurgitation (MR). However, a recent prospective study showed a significant overestimation of RVol by the echocardiographic PISA method compared with the MR volume measured using magnetic resonance imaging. We aimed to evaluate the frequency of overestimation of RVol by the PISA method and the clinical conditions that require a different quantitative method to correct the overestimation.

Methods: We retrospectively enrolled 166 consecutive patients with degenerative MR and chordae rupture, in whom RVol was measured using both the PISA and two-dimensional Doppler volumetric methods. The volumetric method was used to measure total stroke volume using the two-dimensional Simpson biplane method, and forward stroke volume was measured using pulsed Doppler tracing at the left ventricular (LV) outflow tract. RVol by the volumetric method was calculated using total stroke volume - forward stroke volume. Severe MR was defined as an RVol >60 mL.

Results: All patients had severe MR based on RVol by the PISA method, but 68 (41.1%) showed RVol by the volumetric method values of <60 mL, resulting in discordant results. The patients with discordant results were characterized by a higher prevalence of female sex, lower body surface area, smaller LV diastolic and systolic dimensions and volumes, smaller left atrial volume, smaller PISA angle, and lower frequency of flail leaflets (39.7% vs 62.2%, P = .004). Multivariate analysis revealed that LV end-diastolic volume (LVEDV) and PISA angle were independent factors, with the best cutoff LVEDV and PISA angle being 173 mL and 103°, respectively. During follow-up (median, 3.4 years; interquartile range, 2.0-4.8 years), mitral valve repair and replacement were performed in 103 and six patients, respectively. The 2-year mitral valve surgery-free survival rate was higher in the discordant group (51.8% ± 0.06% vs 31.2% ± 0.05%, P < .001).

Conclusions: Even in the patients with documented chordae rupture, the PISA method alone resulted in inappropriate overestimation of MR severity in a significant proportion of patients. Thus, an additive quantitative method is absolutely necessary in patients with a small LVEDV or narrow PISA angle.
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http://dx.doi.org/10.1016/j.echo.2019.08.020DOI Listing
January 2020

Long-term (10-year) outcomes of stenting or bypass surgery for acute coronary syndromes and stable ischemic heart disease with unprotected left main coronary artery disease.

Am Heart J 2019 12 20;218:9-19. Epub 2019 Aug 20.

Department of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.

Background: Acuity of clinical presentation may influence decision making of percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) for left main coronary artery (LMCA) disease. However, it is undetermined whether clinical indication for myocardial revascularization may affect the relative long-term effect after PCI and CABG.

Methods: In the MAIN-COMPARE study including 2,240 patients with LMCA disease treated with PCI (n = 1102) or CABG (n = 1138), we examined interaction between acuity of clinical presentation (acute coronary syndromes [ACS] or non-ACS) and revascularization strategy on 10-year outcomes. Primary outcome was a composite of all-cause death, Q-wave myocardial infarction, or stroke. Secondary outcomes were all-cause death or target vessel revascularization.

Results: In overall patients, 1,603 patients (71.6%) presented with ACS and 637 patients (28.4%) presented with non-ACS. The 10-year adjusted risks for primary composite outcome were similar after PCI and CABG among patients who presented with non-ACS (hazard ratio [HR] 1.07; 95% CI 0.71-1.61) and those who presented with ACS (HR 1.00; 95% CI 0.81-1.24) (P for interaction = .29). The adjusted risks of death were also similar between 2 groups in non-ACS (HR 0.98; 95% CI 0.63-1.51) and ACS (HR 1.02; 95% CI 0.81-1.28) patients (P for interaction = .62). The adjusted risks of target vessel revascularization were consistently higher after PCI in non-ACS (HR 6.38; 95% CI 3.14-12.96) and ACS (HR 3.96; 95% CI 2.80-5.60) patients (P for interaction = .39).

Conclusions: In patients with LMCA disease, we have identified no significant interaction between the acuity of clinical indication and the relative treatment effect of PCI versus CABG on 10-year clinical outcomes.
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http://dx.doi.org/10.1016/j.ahj.2019.08.014DOI Listing
December 2019

Sub-Picosecond Carrier Dynamics Induced by Efficient Charge Transfer in MoTe/WTe van der Waals Heterostructures.

ACS Nano 2019 Aug 29;13(8):9587-9594. Epub 2019 Jul 29.

Department of Electrical and Computer Engineering and NUSNNI , National University of Singapore , 117576 Singapore.

Demonstration of van der Waals (vdW) semiconductor/metal heterostructures (SMHs) based on transition metal dichalcogenides has been a central approach in high-speed electronics by introducing ultrafast carrier dynamics. In this regard, a Weyl semimetal WTe is of great interest due to its vdW layered nature, low work function, and superior electrical properties. However, little is still known about its heterostructures, and a few picoseconds photocarrier lifetimes hinder its applications in high-speed electronics. Here, we propose a SMH: semimetallic Td phase WTe with its sister compound of semiconducting 2H phase MoTe. Time-resolved terahertz (THz) spectroscopy demonstrated that WTe exhibited the significantly shorter carrier lifetimes of sub-picosecond when forming a junction with MoTe. We provided explicit characteristic signatures, revealing charge transfer across the interface and the subsequent interlayer exciton decay. This work not only offers the extension of the THz detection scope of ultrafast phenomena from atomically thin materials but also provides a building block of vertical SMHs for high-speed electronic devices with sub-picosecond photocarrier lifetimes.
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http://dx.doi.org/10.1021/acsnano.9b04701DOI Listing
August 2019

Effect of Age and Sex on Outcomes After Stenting or Bypass Surgery in Left Main Coronary Artery Disease.

Am J Cardiol 2019 09 6;124(5):678-687. Epub 2019 Jun 6.

Department of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.

Age and sex contribute to determining coronary revascularization strategies for patients with left main coronary artery (LMCA) disease. We examined age- and sex-related differences in comparative outcomes after percutaneous coronary intervention (PCI) or coronary-artery bypass grafting (CABG) for LMCA disease. A total of 4,001 patients with LMCA disease (men, n = 3,100, women, n = 901) who underwent PCI (n = 2,615) or CABG (n = 1,386) from the Interventional Research Incorporation Society-Left MAIN Revascularization registry were analyzed. Patients were stratified into subgroups according to the tertiles of age (<60 years, 60 to 69 years, and ≥70 years) and sex. The primary outcome was the composite of death from any cause, myocardial infarction, or stroke. During the median 6.3 years of follow-up, the adjusted risks for primary outcome after PCI relative to CABG were similar in patients aged <60 years (hazard ratio [HR]: 0.64, 95% confidence interval [CI]: 0.35 to 1.16), 60 to 69 years (HR: 1.21; 95% CI: 0.82 to 1.80), and ≥70 years (HR: 0.90; 95% CI: 0.66 to 1.22) with no significant age-related interactions (P = 0.57). The primary outcome risks following PCI versus CABG were similar between male (HR: 0.92; 95% CI: 0.72 to 1.17) and female (HR: 0.89; 95% CI: 0.52 to 1.50) (P = 0.65). Significant interactions were absent for age or sex and revascularization type for all-cause mortality (P = 0.34 for age and P = 0.99 for sex), repeat revascularization (P = 0.10 for age and P = 0.65 for sex), and major adverse cardiac or cerebrovascular events (P = 0.29 for age and P = 0.30 for sex). In conclusion, there were no significant age- or sex-related differences in comparative outcomes after PCI or CABG for LMCA disease.
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http://dx.doi.org/10.1016/j.amjcard.2019.05.061DOI Listing
September 2019

Nutritional status and risk of all-cause mortality in patients undergoing transcatheter aortic valve replacement assessment using the geriatric nutritional risk index and the controlling nutritional status score.

Clin Res Cardiol 2020 Feb 25;109(2):161-171. Epub 2019 May 25.

Department of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, South Korea.

Background: Nutritional status, a key marker of patient frailty, is an important prognostic factor after transcatheter aortic valve replacement (TAVR). Few investigations have evaluated the clinical usefulness of nutritional assessment tools for predicting the risk of mortality following TAVR.

Methods: A total of 412 patients with symptomatic severe AS who underwent TAVR between March 2010 and August 2017 were stratified into subgroups by their Geriatric Nutritional Risk Index [GNRI, low ≤ 98 vs. high > 98 (better nutritional status)] and Controlling Nutritional Status (CONUT) score [low ≤ 3 vs. high ≥ 4; (poorer nutritional status)]. The primary study outcome was all-cause mortality at 1 year.

Results: Patients with low GNRI score showed a significantly higher 1-year mortality rate as compared to those with high GNRI score (13.0% vs. 3.2%, respectively; P = 0.001). Similarly, patients with high CONUT score had a significantly higher rate of 1-year mortality than those with low CONUT score (15.7% vs. 6.2%, respectively; P = 0.005). However, in multivariable Cox proportional-hazards models, low GNRI was the only independent predictor of mortality (adjusted hazard ratio, 3.77; 95% confidence interval 1.54-9.20; P = 0.004). Overall, integration of GNRI into conventional risk models of STS score or logistic EuroSCORE resulted in improved predictive value for mortality measured by the net reclassification improvement and the integrated discrimination improvement.

Conclusions: In patients undergoing TAVR, low GNRI (but not high CONUT score) was independently associated with a higher risk of 1-year mortality. Further research is required to determine whether nutritional screening and management can improve clinical outcomes in patients undergoing TAVR.
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http://dx.doi.org/10.1007/s00392-019-01497-9DOI Listing
February 2020

The Efficacy of Body Mass Index and Total Body Fat Percent in Diagnosis Obesity according to Menopausal Status.

J Menopausal Med 2019 Apr 25;25(1):55-62. Epub 2019 Apr 25.

Department of Obstetrics and Gynecology, Pusan National University School of Medicine and Medical Research Institute, Pusan National University Hospital, Busan, Korea.

Objectives: Body mass index (BMI) is commonly used in epidemiological study or clinical center. However, it is not exactly correlated with body fat composition and does not reflect sex, age, or race. The aim of this article is to evaluate the validity of BMI standards relative to total body fat (TBF) and to estimate new BMI criteria that correspond to TBF for obesity, especially for Asian postmenopausal women.

Methods: A total 3,936 patients were included in this cross-sectional study, including 1,565 premenopausal and 2,371 postmenopausal women. At the time of visit, demographic data were collected. We demonstrated the validity of BMI cut-point of 25 kg/m by using area under the curve (AUC), and presented the empirical optimal BMI cut-point by using Youden's index and overall accuracy in both premenopausal and postmenopausal women.

Results: BMI-defined obesity (≥ 25 kg/m) represents high AUC values (> 0.9) for each TBF. In premenopausal women, TBF ≥ 38% and corresponding BMI value was 29.45 kg/m indicated the highest both Youden's index and overall accuracy. In comparison, postmenopausal women who were TBF ≥ 38% showed the highest Youden's index and overall accuracy, and corresponding BMI value was 26.45 kg/m.

Conclusions: We proposed new BMI criteria for obesity by using TBF reference. With application of bioelectrical impedance analysis, the diagnosis of obesity using BMI criteria may differ between premenopausal and postmenopausal women.
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http://dx.doi.org/10.6118/jmm.2019.25.1.55DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6487284PMC
April 2019

Validation of three-dimensional echocardiographic principal strain analysis for assessing left ventricular contractility: An animal study.

Med Phys 2019 May 14;46(5):2137-2144. Epub 2019 Apr 14.

Division of Cardiology, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.

Purpose: The three-dimensional (3D) principal strain represents the major direction and magnitude of the deformation by its definition and can be measured using 3D echocardiography. We aimed to validate 3D echocardiographic left ventricular (LV) global principal strains as an assessment of LV contractility by comparison with gold standard invasive measurements.

Methods: In 14 beagles, the LV pressure-volume loop was recorded to invasively measure the end-systolic pressure-volume relationship (ESPVR) and dP/dt as reference indicators representing LV contractility. The echocardiographic image was obtained simultaneously, and endocardial motions and volume changes were extracted in the form of speckle-tracking point grids to calculate strains. High or low inotropic states were induced pharmacologically by using an intravenous infusion of dobutamine and esmolol, respectively.

Results: The direction of 3D endocardial global principal strain (GP1S) appeared to be circumferential. The dP/dt showed the highest Pearson's correlation coefficients with GP1S (r = -0.845, P < 0.001), whereas ESPVR showed the best correlation with global secondary strain (GP2S; r = -0.819, P < 0.001). In comparison with GP1S and GP2S, global circumferential (GCS) and longitudinal strains (GLS) tended to correlate less with invasive measurements, respectively. LV ejection fraction showed excellent correlations with GP1S or GCS, but the correlation with GLS was relatively weak. The correlations between invasive measurements and GP2S or GLS were strengthened when strains were corrected by the LV residual volume ratio, whereas those of GP1S or GCS were weakened after correction.

Conclusions: The principal direction of the LV endocardial contraction presents circumferential behavior reflecting LV volume change. The 3D principal strains derived from 3D echocardiography are reliable indicators for LV contractility and seem better than conventional strains.
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http://dx.doi.org/10.1002/mp.13509DOI Listing
May 2019

Long-term trends of treatment effect of stenting or bypass surgery in patients with ostial or shaft left main coronary artery disease.

Catheter Cardiovasc Interv 2019 Sep 5;94(3):315-322. Epub 2019 Feb 5.

Department of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.

Background: Little is known about how the relative treatment effect of percutaneous coronary intervention (PCI) and coronary-artery bypass grafting (CABG) on clinical outcomes in ostial or shaft left main coronary artery (LMCA) disease has evolved over time.

Methods: This study included 2,112 patients with ostial or shaft LMCA disease from IRIS-MAIN registry who underwent PCI (n = 1,329) or CABG (n = 783). Patients were stratified by time period based on stent type availability: wave 1 (1995-2002, bare-metal stent [BMS] era); wave 2 (2003-2006, first-generation drug-eluting stent [DES] era); and wave 3 (2007-2014, second-generation DES era).

Results: Compared to CABG, PCI has been used more frequently from wave 1 to wave 3. PCI showed substantial improvements over time with respect to death (P for trend = 0.012); the composite of death, myocardial infarction (MI), or stroke (P for trend = 0.047); repeat revascularization (P for trend < 0.001); and major adverse cardiac and cerebrovascular events (MACCE; a composite of death, MI, stroke, or repeat revascularization) (P for trend < 0.001). By contrast, outcomes of CABG remained relatively stable over time. The gap between the treatment effects of CABG vs PCI for MACCE has narrowed over time; the adjusted hazard ratios for CABG compared to PCI during wave 1, 2, and 3 were 0.41 (95% confidence interval [CI]: 0.22-0.76), 0.47 (95% CI: 0.31-0.71), and 0.78 (95% CI: 0.50-1.20), respectively.

Conclusions: In patients with ostial or shaft LMCA disease, significant improvements in PCI outcomes resulted in a progressive decline in the gap between the outcomes of CABG and PCI.
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http://dx.doi.org/10.1002/ccd.28119DOI Listing
September 2019

Thromboembolic Risk of Imaging-Confirmed Coronary Artery Disease Without Myocardial Infarction in Patients With Nonvalvular Atrial Fibrillation.

Am J Cardiol 2019 04 24;123(8):1287-1292. Epub 2019 Jan 24.

Department of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.

The implication of coronary artery disease (CAD) without the clinical manifestation of myocardial infarction (non-MI-CAD) on thromboembolic events in patients with nonvalvular atrial fibrillation (NVAF) is not well evaluated. We hypothesized that non-MI-CAD would have a similar risk of future thromboembolism as MI-CAD. Clinical data for 17,073 consecutive patients (mean age, 64.3 years; males, 64.9%) diagnosed with NVAF at our center were analyzed. CAD was defined as stenosis of ≥50% stenosis of major coronary arteries identified using coronary artery angiography or coronary computed tomographic angiography. The main outcome of the present study was the rate of thromboembolic events (ischemic stroke and systemic embolism) during the follow-up period (3.1 ± 2.4 years). A total of 1,011 patients (5.9%) were diagnosed with CAD without clinical manifestation of MI (non-MI-CAD) and 708 (4.1%) had a history or diagnosis of MI-CAD. Thromboembolic events occurred in 1,007 patients (5.9%) during follow-up. The groups were at high risk of future thromboembolic events determined using univariate (hazard ratio [HR] 1.55; 95% confidence interval [CI] 1.25 to 1.91; p <0.001 for non-MI-CAD and HR 2.14; 95% CI 1.70 to 2.69; p <0.001 for MI-CAD) and multivariate analysis adjusted for CHADS-VASc score components and relevant variables (HR 1.42; 95% CI 1.15 to 1.77; p = 0.001 for non-MI-CAD and HR 1.62; 95% CI 1.28 to 2.06; p <0.001 for MI-CAD); this trend was consistent in patients who did not receive anticoagulants during follow-up (n = 8,032, 47.0%). In conclusion, non-MI-CAD is an important predictor of thromboembolic events in patients with NVAF.
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http://dx.doi.org/10.1016/j.amjcard.2019.01.023DOI Listing
April 2019

Prognostic value of echocardiographic parameters for right ventricular function in patients with acute non-massive pulmonary embolism.

Heart Vessels 2019 Jul 22;34(7):1187-1195. Epub 2019 Jan 22.

Division of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.

A prognostic value of right ventricular (RV) systolic function assessed by echocardiography in patients with acute non-massive pulmonary embolism (PE) remains controversial. The hypothesis was RV free wall strain measured using speckle-tracking echocardiography might be a powerful prognostic factor in those patients. We aimed to evaluate the prognostic value of echocardiographic measurements of RV systolic function for clinical outcomes and to assess the correlation between the echocardiographic RV function parameters in patients with acute non-massive PE. Between November 2013 and September 2016, 144 consecutive patients diagnosed as acute non-massive pulmonary embolism were prospectively enrolled and echocardiographic evaluations were performed within 1 week of diagnosis to measure various parameters of RV systolic function. The primary endpoint was in-hospital events, the composite of in-hospital PE-related death, need of additive treatments such as thrombolysis or pulmonary artery thromboembolectomy, and need of inotropics due to unstable vital sign. Among patients (mean age 60.3 ± 14.7 years, 50% female) with acute non-massive PE, the in-hospital event rate was 11.1% (16 of 144 patients). In multivariate logistic regression analysis, after adjustment of confounding factors such as age, gender, and diabetes mellitus, RV free wall strain [odd ratio (OR) 1.12, 95% confidence interval (CI) 1.04-1.21, p = 0.002] and RV global wall strain (OR 1.20, 95% CI 1.07-1.35, p = 0.002) were independent predictors for in-hospital events. The event rates were significantly different between groups classified based on RV free wall strain with cut-off value of - 15.85% (p < 0.001). RV strain assessed with speckle-tracking echocardiography is an independent prognostic marker for in-hospital events in patients with acute non-massive PE. Our results may help identify high-intermediate risk patients who need a closer monitoring.
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http://dx.doi.org/10.1007/s00380-019-01340-1DOI Listing
July 2019

Relation of Body Mass Index to Risk of Death or Stroke in Patients Who Underwent Transcatheter Aortic Valve Implantation.

Am J Cardiol 2019 02 24;123(4):638-643. Epub 2018 Nov 24.

Department of Cardiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, South Korea.

Obesity and overweight have been associated with better clinical outcomes in different populations with a diverse spectrum of cardiovascular disease (obesity paradox). However, conflicting data exist about the relation between body mass index (BMI) and outcomes after transcatheter aortic valve implantation (TAVI). The aim of this study is to evaluate the association of body mass index with clinical outcomes in patients with severe aortic stenosis (AS) who underwent TAVI. The study cohort included 379 consecutive patients with symptomatic severe AS who underwent TAVI between March 2010 and February 2017 in 3 centers in East Asia. Patients were grouped into tertiles of baseline BMI (first tertile: ≤22.3 kg/m, second tertile: 22.4 to 24.8 kg/m, and third tertile: ≥24.9 kg/m). The primary outcome was a composite of death from any causes or stroke at 1 year. The median (interquartile range) BMI was 23.5 (21.8 to 26.1) kg/m. During the median follow-up of 18.4 months, there were 69 deaths and 23 strokes. At 1 year, the primary outcome occurred in 21.9% in the first tertile, 18.7% in the second tertile, and 7.8% in the third tertile, respectively (p = 0.009). After adjustment for confounding variables, an inverse relation was observed between BMI and primary outcome: with the third BMI tertile as the reference category, the adjusted hazard ratios were 2.51 (95% confidence interval, 1.20 to 5.26) for the second BMI tertile and 2.61 (95% confidence interval, 1.20 to 5.66) for the first BMI tertile. In conclusion, in patients with severe AS who underwent TAVI, an inverse association between BMI and the risk of death or stroke was observed.
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http://dx.doi.org/10.1016/j.amjcard.2018.11.015DOI Listing
February 2019

Risk factors related to the recurrence of endometrioma in patients with long-term postoperative medical therapy.

Ginekol Pol 2018;89(11):611-617

Department of Obstetrics and Gynecology, Pusan National University School of Medicine Biomedical Research Institute, Pusan National University Hospital, Busan, Korea.

Objectives: The purpose of this study was to identify clinical risk factors for the recurrence of ovarian endometrioma after ovarian cystectomy in Korean women with long-term postoperative medical therapy.

Material And Methods: A total of 134 patients who were surgically treated for endometriotic cysts at Pusan National University Hospital were included in this retrospective study. All patients received long-term postoperative medical treatment for at least 12 months after the first-line conservative surgery. Several epidemiologic variables were analyzed as possible risk factors for recurrence. Endometrioma recurrence was considered when a cystic mass was observed on transvaginal or transrectal sonography. Statistical analysis was performed using independent t-tests for parametric continuous variables.

Results: The mean follow-up period for the 134 patients was 56.5 ± 14.3 months (range, 36-120 months) and the mean duration of the medical therapy was 17.9 ± 17.3 months (range, 12-120 months). The overall recurrence rate was 35/134 (26.12%). Our univariate analysis showed statistically significant differences between the recurrent and non-recurrent groups in terms of weight (P = 0.013), body mass index (P = 0.007), age at the time of surgery (P = 0.013), the diameter of the largest cyst (P = 0.001), the presence of dysmenorrhea (P < 0.0001), and postoperative pregnancy (P = 0.016). Multivariate analysis showed that body mass index (OR 1.153, 95% CI 1.003-1.326, P = 0.046), age at the time of surgery (OR 0.924, 95% CI 0.860-0.992, P = 0.029), and presence of dysmenorrhea (OR 12.226, 95% CI 3.543-42.188, P < 0.0001) were significantly correlated with the recurrence of endometrioma.

Conclusions: We found that patients with dysmenorrhea after surgery, and a younger age of the patient at the time of surgery were the highest risk factors associated with the recurrence of endometrioma, despite long-term postoperative medication.
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http://dx.doi.org/10.5603/GP.a2018.0105DOI Listing
February 2019

Effects of external electric field and anisotropic long-range reactivity on charge separation probability.

J Chem Phys 2017 Oct;147(14):144111

Department of Chemistry, Seoul National University, Seoul 08826, South Korea.

We consider the effects of external electric field and anisotropic long-range reactivity on the recombination dynamics of a geminate charge pair. A closed-form analytic expression for the ultimate separation probability of the pair is presented. In previous theories, analytic expressions for the separation probability were obtained only for the case where the recombination reaction can be assumed to occur at a contact separation. For this case, Noolandi and Hong obtained an exact solution, but their expression for the separation probability was too complicated to evaluate. Hence an approximate analytic expression proposed by Braun has been widely used. However, Braun's expression overestimates the separation probability when the electric field is large. In this work, we present an approximate analytic expression that is accurate enough for all parameter values. In addition, the expression is also applicable when the interaction between the geminate charge pair is described by screened Coulombic potential, and the recombination reaction has an anisotropic and long-range reactivity. We also provide the expression for the separation probability when the initial separation between the geminate charge pair is larger than the contact distance.
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http://dx.doi.org/10.1063/1.5000882DOI Listing
October 2017
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