Publications by authors named "John A Ambrose"

70 Publications

New Precordial T wave Inversions in Hospitalized Patients.

Am J Med 2021 Nov 20. Epub 2021 Nov 20.

Division of Cardiovascular Medicine, University of California San Francisco, Fresno, California.

Background: The incidence of precordial T changes has been described in athletes and in specific populations, while the etiology in a large patient population admitted to the hospital has not previously been reported.

Methods: All ECGs read by the same physician with new (compared to prior ECGs) or presumed new (no prior ECGs) precordial T wave inversions of >1 mm (0.1 mV) in multiple precordial leads were retrospectively reviewed and various ECG, patient-related and imaging parameters assessed. 226 patients and their ECGs were initially selected for analysis. Of these, 35 were eliminated leaving 191 for the final analysis.

Results: Patients and their ECGs were divided into 5 groups based on diagnosis and incidence including Wellens' syndrome, takotsubo, type 2 myocardial infarction, other (including multiple diagnoses) and unknown. While subtle differences including number of T inversion leads, depth of T waves, QTc intervals and other variables were present between some groups, diagnosis in individual cases required appropriate clinical, laboratory and/or imaging studies. For example, although Wellens' syndrome was identified in <20% of cases, a presenting history of chest discomfort with precordial T changes either on the admission or next day ECG was highly sensitive and specific for this diagnosis. In some cases, Type 2 myocardial infarction can also have a Wellens' like ECG phenotype without significant left anterior descending disease.

Conclusions: Precordial T wave changes in hospitalized patients have various etiologies and, in individual cases, the changes on the ECG alone cannot easily distinguish the presumptive diagnosis and additional data are required.
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http://dx.doi.org/10.1016/j.amjmed.2021.10.030DOI Listing
November 2021

The Reply.

Authors:
John A Ambrose

Am J Med 2021 03;134(3):e227

Professor of Medicine, Division of Cardiology, University of California, San Francisco-Fresno, Fresno. Electronic address:

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http://dx.doi.org/10.1016/j.amjmed.2020.10.039DOI Listing
March 2021

The Look Inside: Is it Clinically Relevant?

JACC Cardiovasc Imaging 2021 06 18;14(6):1246-1248. Epub 2020 Nov 18.

Department of Medicine, Division of Cardiology, University of California-San Francisco, Fresno Medical Education Program, Fresno, California, USA.

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http://dx.doi.org/10.1016/j.jcmg.2020.08.026DOI Listing
June 2021

Reducing Tobacco-Related Morbidity and Mortality-A Call to Action.

JAMA Cardiol 2020 Aug;5(8):860-862

Kansas City VA, University of Kansas Medical Center, Kansas City.

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http://dx.doi.org/10.1001/jamacardio.2020.0996DOI Listing
August 2020

Reducing Tobacco-Related Disability in Chronic Smokers.

Am J Med 2020 08 20;133(8):908-915. Epub 2020 Apr 20.

University of Kansas Medical Center, Kansas City Veterans' Administration, Kansas City, Mo.

Tobacco consumption (predominantly cigarettes) is the leading preventable cause of mortality worldwide. Although the major focus of strategies to reduce mortality from tobacco must include prevention of future generations from initially gaining access, some smokers are unwilling or unable to quit. Can the higher risk chronic smoker be identified and can their risk be reduced? The risk of adverse events in cigarette smokers is influenced by the intensity and duration of cigarette smoking or secondhand exposure, associated conventional risk factors, environmental stressors, and certain genetic variants and epigenetic modifiers. Recent data suggest that inflammatory markers such as high-sensitivity C-reactive protein (hs CRP) and targeted imaging can identify some smokers at higher risk. As smoking is prothrombotic, aspirin initiation and expanded statin use might reduce cardiovascular risk in those who do not presently meet criteria for these therapies, but further study is required. Thus, although advocacy for smoking cessation should always be the primary approach, increased efforts are needed to identify and potentially treat those who are unable or unwilling to quit.
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http://dx.doi.org/10.1016/j.amjmed.2020.03.025DOI Listing
August 2020

Anatomic or functional testing in stable patients with suspected CAD: contemporary role of cardiac CT in the ISCHEMIA trial era.

Int J Cardiovasc Imaging 2020 Jul 16;36(7):1351-1362. Epub 2020 Mar 16.

Division of Cardiology, Department of Internal Medicine, University of California San Francisco-Fresno, Fresno, USA.

One of the foundations of the management of patients with suspected coronary artery disease (CAD) is to avoid unnecessary invasive coronary angiography (ICA) referrals. However, the diagnostic yield of ICA following abnormal conventional stress testing is low. The ability of ischemia testing to predict subsequent myocardial infarction and death is currently being challenged, and more than half of cardiac events among stable patients with suspected CAD occur in those with normal functional tests. The optimal management of patients with stable CAD remains controversial and ischemia-driven interventions, though improving anginal symptoms, have failed to reduce the risk of hard cardiovascular events. In this context, there is an ongoing debate whether the initial diagnostic test among patients with stable suspected CAD should be a functional test or coronary computed tomography angiography. Aside from considering the specific characteristics of individual patients and local availability and conditions, the choice of the initial test relates to whether the objective concerns its role as gatekeeper for ICA, prognosis, or treatment decision-making. Therefore, the aim of this review is to provide a contemporary overview of these issues and discuss the emerging role of CCTA as the upfront imaging tool for most patients with suspected CAD.
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http://dx.doi.org/10.1007/s10554-020-01815-7DOI Listing
July 2020

Environmental Tobacco Smoke and Cardiovascular Disease.

Int J Environ Res Public Health 2018 12 31;16(1). Epub 2018 Dec 31.

Division of Cardiovascular Medicine, University of California San Francisco, Fresno, CA 93701, USA.

Environmental tobacco smoke (ETS) and its sequelae are among the largest economic and healthcare burdens in the United States and worldwide. The relationship between active smoking and atherosclerosis is well-described in the literature. However, the specific mechanisms by which ETS influences atherosclerosis are incompletely understood. In this paper, we highlight the definition and chemical constituents of ETS, review the existing literature outlining the effects of ETS on atherogenesis and thrombosis in both animal and human models, and briefly outline the public health implications of ETS based on these data.
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http://dx.doi.org/10.3390/ijerph16010096DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6339042PMC
December 2018

Understanding myocardial infarction.

F1000Res 2018 3;7. Epub 2018 Sep 3.

Division of Cardiology, Department of Internal Medicine, University of California San Francisco-Fresno, 2335 E. Kashian Lane, Suite 460, Fresno, CA 97301, USA.

Over the last 40 years, our understanding of the pathogenesis of myocardial infarction has evolved and allowed new treatment strategies that have greatly improved survival. Over the years, there has been a radical shift in therapy from passive healing of the infarction through weeks of bed rest to early discharge usually within 2 to 3 days as a result of immediate reperfusion strategies and other guideline-directed medical therapies. Nevertheless, challenges remain. Patients who develop cardiogenic shock still face a high 30-day mortality of at least 40%. Perhaps even more important is how do we identify and prevent patients from developing myocardial infarction in the first place? This article discusses these milestones of therapy and considers important issues for progress in the future.
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http://dx.doi.org/10.12688/f1000research.15096.1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6124376PMC
July 2019

Strategies for the Prevention of Coronary Artery Disease Complications: Can We Do Better?

Am J Med 2018 09 3;131(9):1003-1009. Epub 2018 May 3.

University of California San Francisco, Fresno.

Billions of dollars have been spent over the past 25 years on developing new therapies for the prevention/treatment of adverse cardiac events related to atherosclerotic cardiovascular disease. Although some therapies have been lifesaving, several mega-randomized studies have shown only a <2% absolute reduction in adverse events with a large residual event rate. Is all this money well spent? Atherosclerosis develops decades before an adverse event, and the trials previously alluded to have nearly always been applied to secondary prevention, decades after disease initiation. Will earlier intervention result in a lower incidence of events? Individuals with an absence of the usual cardiac risk factors have a lifelong low incidence of events. Early initiation of strategies against the common cardiovascular risk factors in primary or primordial prevention will lower the incidence of adverse events, although many groups have not been well studied, including individuals younger than 40 years of age. New strategies are required to realize a radical reduction in events, and this article proposes new methods of prevention/treatment for coronary artery disease complications.
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http://dx.doi.org/10.1016/j.amjmed.2018.04.006DOI Listing
September 2018

In-Hospital Outcomes of Percutaneous Coronary Intervention in America's Safety Net: Insights From the NCDR Cath-PCI Registry.

JACC Cardiovasc Interv 2017 08;10(15):1475-1485

University of California, San Francisco, Fresno, California. Electronic address:

Objectives: This study compared risk-adjusted percutaneous coronary intervention (PCI) outcomes of safety-net hospitals (SNHs) and non-SNHs.

Background: Although risk adjustment is used to compare hospitals, SNHs treat a disproportionate share of uninsured and underinsured patients, who may have unmeasured risk factors, limited health care access, and poorer outcomes than patients treated at non-SNHs.

Methods: Using the National Cardiovascular Data Registry CathPCI Registry from 2009 to 2015, we analyzed 3,746,961 patients who underwent PCI at 282 SNHs (hospitals where ≥10% of PCI patients were uninsured) and 1,134 non-SNHs. The relationship between SNH status and risk-adjusted outcomes was assessed.

Results: SNHs were more likely to be lower volume, rural hospitals located in the southern states. Patients treated at SNHs were younger (63 vs. 65 years), more often nonwhite (17% vs. 12%), smokers (33% vs. 26%), and more likely to be admitted through the emergency department (48% vs. 38%) and to have an ST-segment elevation myocardial infarction (20% vs. 14%) than non-SNHs (all p < 0.001). Patients undergoing PCI at SNHs had higher risk-adjusted in-hospital mortality (odds ratio: 1.23; 95% confidence interval: 1.17 to 1.32; p < 0.001), although the absolute risk difference between groups was small (0.4%). Risk-adjusted bleeding (odds ratio: 1.05; 95% confidence interval: 1.00 to 1.12; p = 0.062) and acute kidney injury rates (odds ratio: 1.01; 95% confidence interval: 0.96 to 1.07; p = 0.51) were similar.

Conclusions: Despite treating a higher proportion of uninsured patients with more acute presentations, risk-adjusted PCI-related in-hospital mortality of SNHs is only marginally higher (4 additional deaths per 1,000 PCI cases) than non-SNHs, whereas risk-adjusted bleeding and acute kidney injury rates are comparable.
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http://dx.doi.org/10.1016/j.jcin.2017.05.042DOI Listing
August 2017

Normalization of Testosterone Levels After Testosterone Replacement Therapy Is Not Associated With Reduced Myocardial Infarction in Smokers.

Mayo Clin Proc Innov Qual Outcomes 2017 Jul 18;1(1):57-66. Epub 2017 May 18.

Division of Cardiovascular Research, Kansas City VA Medical Center, Kansas City, MO.

Objective: To examine the effect of cigarette smoking (CS) status and total testosterone (TT) levels after testosterone replacement therapy (TRT) on all-cause mortality, myocardial infarction (MI), and stroke in male smokers and nonsmokers without history of MI and stroke.

Participants And Methods: Data from 18,055 males with known CS status and low TT levels who received TRT at the Veterans Health Administration between December 1, 1999, and May 31, 2014, were grouped into (1) current smokers with normalized TT, (2) current smokers with nonnormalized TT, (3) nonsmokers with normalized TT, and (4) nonsmokers with nonnormalized TT. Combined effect of CS status and TT level normalization after TRT on all-cause mortality, MI, and stroke was compared using propensity score-weighted Cox proportional hazard models.

Results: Normalization of serum TT levels in nonsmokers was associated with a significant decrease in all-cause mortality (hazard ratio [HR]=0.526; 95% CI, 0.477-0.581; <.001) and MI (HR=0.717; 95% CI, 0.522-0.986; <.001). Among current smokers, normalization of serum TT levels was associated with a significant decrease in only all-cause mortality (HR=0.563; 95% CI, 0.488-0.649; <.001) without benefit in MI (HR=1.096; 95% CI, 0.698-1.720; =.69). Importantly, compared with nonsmokers with normalized TT, all-cause mortality (HR=1.242; 95% CI, 1.104-1.396; <.001), MI (HR=1.706; 95% CI, 1.242-2.342; =.001), and stroke (HR=1.590; 95% CI, 1.013-2.495; =.04) were significantly higher in current smokers with normalized TT.

Conclusion: We conclude that active CS may negate the protective effect of testosterone level normalization on all-cause mortality and MI after TRT.
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http://dx.doi.org/10.1016/j.mayocpiqo.2017.05.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6135014PMC
July 2017

Normalization of Testosterone Levels After Testosterone Replacement Therapy Is Associated With Decreased Incidence of Atrial Fibrillation.

J Am Heart Assoc 2017 May 9;6(5). Epub 2017 May 9.

Division of Cardiovascular Medicine, Kansas City VA Medical Center, Kansas City, MO

Background: Atrial fibrillation (AF) is the most common cardiac dysrhythmia associated with significant morbidity and mortality. Several small studies have reported that low serum total testosterone (TT) levels were associated with a higher incidence of AF. In contrast, it is also reported that anabolic steroid use is associated with an increase in the risk of AF. To date, no study has explored the effect of testosterone normalization on new incidence of AF after testosterone replacement therapy (TRT) in patients with low testosterone.

Methods And Results: Using data from the Veterans Administrations Corporate Data Warehouse, we identified a national cohort of 76 639 veterans with low TT levels and divided them into 3 groups. Group 1 had TRT resulting in normalization of TT levels (normalized TRT), group 2 had TRT without normalization of TT levels (nonnormalized TRT), and group 3 did not receive TRT (no TRT). Propensity score-weighted stabilized inverse probability of treatment weighting Cox proportional hazard methods were used for analysis of the data from these groups to determine the association between post-TRT levels of TT and the incidence of AF. Group 1 (40 856 patients, median age 66 years) had significantly lower risk of AF than group 2 (23 939 patients, median age 65 years; hazard ratio 0.90, 95% CI 0.81-0.99, =0.0255) and group 3 (11 853 patients, median age 67 years; hazard ratio 0.79, 95% CI 0.70-0.89, =0.0001). There was no statistical difference between groups 2 and 3 (hazard ratio 0.89, 95% CI 0.78- 1.0009, =0.0675) in incidence of AF.

Conclusions: These novel results suggest that normalization of TT levels after TRT is associated with a significant decrease in the incidence of AF.
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http://dx.doi.org/10.1161/JAHA.116.004880DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5524065PMC
May 2017

Finding the High-Risk Patient in Primary Prevention Is Not as Easy as a Conventional Risk Score!

Am J Med 2016 Dec 24;129(12):1329.e1-1329.e7. Epub 2016 Aug 24.

University of California, San Francisco, Fresno.

Patients with coronary artery disease or its equivalent are an appropriate target for guideline-directed therapy. However, finding and treating the individuals at risk for myocardial infarction or sudden death in primary prevention has been problematic. Most initial cardiovascular events are acute syndromes, and only a minority of these occurs in those deemed high risk by contemporary algorithms. Even newer noninvasive modalities cannot detect a majority of those at risk. Furthermore, accurate and early detection of high risk/vulnerability does not guarantee event prevention. Until new tools can be identified, one should consider a few simplistic solutions. In addition to a greater emphasis on lifestyle, earlier use of statins than currently recommended and a direct assault on tobacco could go a long way in reducing acute syndromes and cardiovascular mortality. To achieve the tobacco goal, the medical community would have to be directly and communally engaged.
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http://dx.doi.org/10.1016/j.amjmed.2016.07.014DOI Listing
December 2016

Left Atrial Area and Right Ventricle Dimensions in Non-gated Axial Chest CT can Differentiate Pulmonary Hypertension Due to Left Heart Disease from Other Causes.

J Cardiovasc Comput Tomogr 2016 May-Jun;10(3):246-50. Epub 2016 Jan 30.

UCSF Fresno, Cardiovascular Division, 2823 Fresno St, Fresno, CA 93721, USA.

Background: It is unknown whether axial non-gated CT can distinguish World Health Organization Group 2 pulmonary hypertension (pulmonary hypertension due to left heart disease) from non-Group 2 pulmonary hypertension.

Objective: The study was performed to identity imaging parameters in non-gated chest CT that differentiate Group 2 from non-Group 2 pulmonary hypertension.

Methods: Among 158 patients who underwent right heart catheterization for evaluation of pulmonary hypertension, 112 had sufficient data and chest CT for review. Invasive hemodynamic data and numerous variables obtained from axial CT images (maximum diameters of main, right, left pulmonary arteries, ascending aorta, main pulmonary artery to ascending aorta diameter ratio, right atrial diameter, left atrial area and right ventricular size) were collected. CT variables were validated against hemodynamic data to identify parameters that would allow to differentiate pulmonary hypertension due to left heart disease (Group 2) from non-Group 2 pulmonary hypertension.

Results: Based on right heart catheterization data, we identified 53 patients with Group 2 pulmonary hypertension, 50 patients with non-Group 2 pulmonary hypertension, and 9 subjects with no pulmonary hypertension. In patients with a dilated pulmonary artery (n = 84), the ROC curve for left atrial area (area under the ROC curve 0.76 ± 0.06) independently distinguished patients with Group 2 pulmonary hypertension (n = 42) from patients with non-Group 2 pulmonary hypertension (n = 42). A dilated left atrium (>20 mm(2)) in combination with a normal right ventriuclar size had a sensitivity of 77% and specificity of 94% for Group 2 pulmonary hypertension.

Conclusions: In patients with a dilated pulmonary artery on chest CT, left atrial area and right ventricular dimensions may aid to diagnose pulmonary hypertension and to distinguish underlying cardiac disease from other causes.
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http://dx.doi.org/10.1016/j.jcct.2016.01.014DOI Listing
April 2017

Normalization of testosterone level is associated with reduced incidence of myocardial infarction and mortality in men.

Eur Heart J 2015 Oct 6;36(40):2706-15. Epub 2015 Aug 6.

Division of Cardiovascular Research, Kansas City VA Medical Center, Kansas City, MO, USA Division of Cardiovascular Diseases, University of Kansas Medical Center, Kansas City, KS, USA Division of Cardiovascular Medicine, Kansas City VA Medical Center, 4801 E. Linwood Boulevard, Kansas City, MO 64128, USA

Aims: There is a significant uncertainty regarding the effect of testosterone replacement therapy (TRT) on cardiovascular (CV) outcomes including myocardial infarction (MI) and stroke. The aim of this study was to examine the relationship between normalization of total testosterone (TT) after TRT and CV events as well as all-cause mortality in patients without previous history of MI and stroke.

Methods And Results: We retrospectively examined 83 010 male veterans with documented low TT levels. The subjects were categorized into (Gp1: TRT with resulting normalization of TT levels), (Gp2: TRT without normalization of TT levels) and (Gp3: Did not receive TRT). By utilizing propensity score-weighted Cox proportional hazard models, the association of TRT with all-cause mortality, MI, stroke, and a composite endpoint was compared between these groups. The all-cause mortality [hazard ratio (HR): 0.44, confidence interval (CI) 0.42-0.46], risk of MI (HR: 0.76, CI 0.63-0.93), and stroke (HR: 0.64, CI 0.43-0.96) were significantly lower in Gp1 (n = 43 931, median age = 66 years, mean follow-up = 6.2 years) vs. Gp3 (n = 13 378, median age = 66 years, mean follow-up = 4.7 years) in propensity-matched cohort. Similarly, the all-cause mortality (HR: 0.53, CI 0.50-0.55), risk of MI (HR: 0.82, CI 0.71-0.95), and stroke (HR: 0.70, CI 0.51-0.96) were significantly lower in Gp1 vs. Gp2 (n = 25 701, median age = 66 years, mean follow-up = 4.6 years). There was no difference in MI or stroke risk between Gp2 and Gp3.

Conclusion: In this large observational cohort with extended follow-up, normalization of TT levels after TRT was associated with a significant reduction in all-cause mortality, MI, and stroke.
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http://dx.doi.org/10.1093/eurheartj/ehv346DOI Listing
October 2015

A Single Controlled Exposure to Secondhand Smoke May Not Alter Thrombogenesis or Trigger Platelet Activation.

Nicotine Tob Res 2016 May 22;18(5):580-4. Epub 2015 Jun 22.

Division of Cardiovascular Medicine, University of California San Francisco, Fresno, CA

Introduction: Chronic secondhand smoke (SHS) exposure increases cardiovascular events, particularly acute thrombotic events. There are little human data on acute SHS exposure. The aim of this study was to determine whether a single controlled exposure of humans to SHS increased thrombogenesis.

Methods: After 6-8 hours fast, subjects (n = 50) were exposed to constant dose SHS (particulate level of 500 μg/m(3)) for 120 minutes in a temperature-regulated and ventilated, simulated bar environment. Blood was drawn before and immediately after SHS exposure for thromboelastography (TEG) and flow cytometry. Maximum clot strength (MA) was measured using TEG and platelet leukocyte aggregates (LPA) were measured as an index of platelet activation. Anti-CD 14 antibodies were used as leukocyte markers and anti-CD 41 antibodies as platelet markers for cytometry. Data were analyzed using students' t test for paired samples.

Results: There was no effect of acute exposure to SHS on platelet activation or thrombogenesis. Also, intra group (smokers [n = 19] and nonsmokers [n = 31]) comparisons of LPA and TEG parameters did not show changes with SHS exposure.

Conclusions: While there are abundant data showing enhanced thrombogenesis and platelet activation following repeated exposure to SHS, our study suggests that a single exposure does not appear to significantly alter thrombin kinetics nor result in platelet activation. The effects of SHS on thrombogenesis might be nonlinear.
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http://dx.doi.org/10.1093/ntr/ntv133DOI Listing
May 2016

Pathophysiology of coronary artery disease leading to acute coronary syndromes.

F1000Prime Rep 2015 14;7:08. Epub 2015 Jan 14.

Department of Medicine, Division of Cardiology, UCSF Fresno Medical Education Program Fresno, CA USA.

Acute myocardial infarction (AMI) and sudden cardiac death (SCD) are among the most serious and catastrophic of acute cardiac disorders, accounting for hundreds of thousands of deaths each year worldwide. Although the incidence of AMI has been decreasing in the US according to the American Heart Association, heart disease is still the leading cause of mortality in adults. In most cases of AMI and in a majority of cases of SCD, the underlying pathology is acute intraluminal coronary thrombus formation within an epicardial coronary artery leading to total or near-total acute coronary occlusion. This article summarizes our current understanding of the pathophysiology of these acute coronary syndromes and briefly discusses new approaches currently being researched in an attempt to define and ultimately reduce their incidence.
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http://dx.doi.org/10.12703/P7-08DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4311268PMC
February 2015

Reducing acute coronary events: the solution is not so difficult!

Am J Med 2015 Feb 3;128(2):105-6. Epub 2014 Sep 3.

Division of Cardiology, Department of Internal Medicine, University of California San Francisco, Fresno.

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http://dx.doi.org/10.1016/j.amjmed.2014.08.017DOI Listing
February 2015

Femoral micropuncture or routine introducer study (FEMORIS).

Cardiology 2014 9;129(1):39-43. Epub 2014 Jul 9.

Division of Cardiology, Department of Internal Medicine, UCSF Fresno Medical Education Program, Fresno, Calif., USA.

Objectives: The Micropuncture® 21-gauge needle may reduce complications related to vessel trauma from inadvertent venous or posterior arterial wall puncture.

Methods: This was a single-center, multiple-user trial. Four hundred and two patients undergoing possible or definite percutaneous coronary intervention (PCI) were randomized 1:1 to an 18-gauge versus a 21-gauge needle. Patients and personnel pulling the sheaths and performing the follow-up were blinded. The primary end point was a composite of access bleeding. Events were tabulated following sheath removal, ≤ 24 h after the procedure and at the follow-up (at 1-2 weeks). End points were blindly adjudicated.

Results: The event rate overall was 12.4% and did not differ significantly between groups, although the 21-gauge needle was found to reduce events by more than one third. An exploratory subgroup analysis of prespecified variables indicated that: patients who did not undergo PCI or elective procedures, female patients and those with a final sheath size of ≤ 6 Fr all had a significant or near-significant reduction of complications with Micropuncture.

Conclusions: Although no significant differences between the use of the 18- and 21-gauge needles were observed, there was a 50-75% reduction with Micropuncture in several subgroups. The study was terminated prematurely. Access site complications may be reduced by the use of the 21-gauge needle, particularly when the risk of bleeding is not high. Further multicenter data will be required to confirm these hypothesis-generating observations.
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http://dx.doi.org/10.1159/000362536DOI Listing
May 2015

Are the culprit lesions severely stenotic?

JACC Cardiovasc Imaging 2013 Oct;6(10):1108-1114

Department of Medicine, Division of Cardiology, UCSF Fresno Medical Education Program, Fresno, California.

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http://dx.doi.org/10.1016/j.jcmg.2013.05.004DOI Listing
October 2013

Mechanisms of coronary thrombosis in cigarette smoke exposure.

Arterioscler Thromb Vasc Biol 2013 Jul 16;33(7):1460-7. Epub 2013 May 16.

Department of Medicine, Division of Cardiology, University of Kansas School of Medicine, KS 93721, USA.

Acute rupture or erosion of a coronary atheromatous plaque and subsequent coronary artery thrombosis cause the majority of sudden cardiac deaths and myocardial infarctions. Cigarette smoking is a major risk factor for acute coronary thrombosis. Indeed, a majority of sudden cardiac deaths attributable to acute thrombosis are in cigarette smokers. Both active and passive cigarette smoke exposure seem to increase the risk of coronary thrombosis and myocardial infarctions. Cigarette smoke exposure seems to alter the hemostatic process via multiple mechanisms, which include alteration of the function of endothelial cells, platelets, fibrinogen, and coagulation factors. This creates an imbalance of antithrombotic/prothrombotic factors and profibrinolytic/antifibrinolytic factors that support the initiation and propagation of thrombosis.
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http://dx.doi.org/10.1161/ATVBAHA.112.300154DOI Listing
July 2013

Frequency of Takotsubo cardiomyopathy in postmenopausal women presenting with an acute coronary syndrome.

Am J Cardiol 2013 Aug 16;112(4):479-82. Epub 2013 May 16.

Division of Cardiovascular Medicine, University of California San Francisco, Fresno, CA, USA.

Takotsubo cardiomyopathy (TC) may be more common than previously reported in postmenopausal women (PMW) presenting with acute coronary syndrome (ACS). TC often masquerades as an ACS with electrocardiographic changes, elevated troponins, and/or chest discomfort. Its exact incidence in ACS is unknown but most studies suggest it is 1% to 2.2%. As most patients with TC are PMW, it was hypothesized that the incidence would be greater in this population. A prospective evaluation was carried out in all middle-aged and older women (≥45 years of age) presumed to be peri- or postmenopausal with an elevated troponin presenting to a community hospital over a 1-year period (July 2011 to July 2012). Troponin results above the upper limit of normal were screened on a daily basis through a computerized system. The patients' in-hospital charts were reviewed and determined if they fulfilled the criteria for acute myocardial infarction according to the universal definition of myocardial infarction. Prespecified criteria were used to identify all patients with TC. Of the 1,297 PMW screened for positive troponins, 323 patients (24.9%) fulfilled the criteria for acute myocardial infarction and of these, 19 (5.9%) met the prespecified criteria for TC. Three additional patients with TC had acute neurologic events. Most patients (81.8%) had the apical variant. In conclusion, TC may be more common than reported in PMW with clinical and laboratory criteria suggesting acute myocardial infarction. Heightened awareness of TC in this population appears warranted.
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http://dx.doi.org/10.1016/j.amjcard.2013.04.010DOI Listing
August 2013

Pathophysiology of coronary thrombus formation and adverse consequences of thrombus during PCI.

Curr Cardiol Rev 2012 Aug;8(3):168-76

Interventional Cardiology Fellow, UCSF Fresno, CA, USA.

Atherosclerosis is a systemic vascular pathology that is preceded by endothelial dysfunction. Vascular inflammation "fuels" atherosclerosis and creates the milieu for episodes of intravascular thromboses. Thrombotic events in the coronary vasculature may lead to asymptomatic progression of atherosclerosis or could manifest as acute coronary syndromes or even sudden cardiac death. Thrombus encountered in the setting of acute coronary syndromes has been correlated with acute complications during percutaneous coronary interventions such as no-reflow, acute coronary occlusion and long term complications such as stent thrombus. This article reviews the pathophysiology of coronary thrombogenesis and explores the complications associated with thrombus during coronary interventions.
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http://dx.doi.org/10.2174/157340312803217247DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3465820PMC
August 2012

Evaluation of plaque composition by intravascular ultrasound "virtual histology": the impact of dense calcium on the measurement of necrotic tissue.

EuroIntervention 2010 Aug;6(3):394-9

Heart Institute, University of São Paulo Medical School, Brazil.

Aims: We aimed to evaluate if the co-localisation of calcium and necrosis in intravascular ultrasound virtual histology (IVUS-VH) is due to artefact, and whether this effect can be mathematically estimated.

Methods And Results: We hypothesised that, in case calcium induces an artefactual coding of necrosis, any addition in calcium content would generate an artificial increment in the necrotic tissue. Stent struts were used to simulate the "added calcium". The change in the amount and in the spatial localisation of necrotic tissue was evaluated before and after stenting (n=17 coronary lesions) by means of a especially developed imaging software. The area of "calcium" increased from a median of 0.04 mm2 at baseline to 0.76 mm2 after stenting (p<0.01). In parallel the median necrotic content increased from 0.19 mm2 to 0.59 mm2 (p<0.01). The "added" calcium strongly predicted a proportional increase in necrosis-coded tissue in the areas surrounding the calcium-like spots (model R2=0.70; p<0.001).

Conclusions: Artificial addition of calcium-like elements to the atherosclerotic plaque led to an increase in necrotic tissue in virtual histology that is probably artefactual. The overestimation of necrotic tissue by calcium strictly followed a linear pattern, indicating that it may be amenable to mathematical correction.
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http://dx.doi.org/10.4244/EIJV6I3A65DOI Listing
August 2010
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