Publications by authors named "I Sakamoto"

367 Publications

Unchanged right ventricular strain in repaired tetralogy of Fallot after pulmonary valve replacement with radial long-axis cine magnetic resonance images.

Sci Rep 2021 Sep 23;11(1):18879. Epub 2021 Sep 23.

Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.

We measured right ventricular (RV) strain by applying a novel postprocessing technique to conventional short-axis cine magnetic resonance imaging in the repaired tetralogy of Fallot (TOF) and investigated whether pulmonary valve replacement (PVR) changes the RV strain. Twenty-four patients with repaired TOF who underwent PVR and 16 healthy controls were enrolled. Global maximum and minimum principal strains (GPS, GPS) and global circumferential and longitudinal strains (GCS, GLS) were measured from short-axis cine images reconstructed radially along the long axis. Strain parameters before and after PVR were compared using paired t-tests. One-way ANOVA with Tukey post-hoc analysis was used for comparisons between the before and after PVR groups and the control group. There were no differences in strain parameters before and after PVR. The GPS before PVR was lower than that in the control group (P = 0.002). Before and after PVR, GCSs were higher and GLSs were lower than those in the control group (before and after GCSs: P = 0.002 for both, before and after GLSs: P < 0.0001 and P = 0.0003). RV strains from radially reconstructed short-axis cine images revealed unchanged myocardial motion after PVR. When compared to the control group, changes in GCS and GLS in TOF patients before and after PVR might be due to RV remodeling.
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http://dx.doi.org/10.1038/s41598-021-98464-0DOI Listing
September 2021

Hemodynamic Characteristics After Fontan Procedure in Patients with Down's Syndrome.

Pediatr Cardiol 2021 Sep 8. Epub 2021 Sep 8.

Department of Pediatric Cardiology, Fukuoka Children's Hospital, 5-1-1 Kashiiteriha Higashi-ku, Fukuoka, 813-0017, Japan.

Patients with Down's syndrome (DS) are generally regarded as not being good candidates for the Fontan procedure. However, detailed hemodynamic changes over time are not fully clarified. A retrospective chart review of all patients with DS who underwent the Fontan procedure and 5 times that number of Fontan patients without DS performed in Fukuoka Children's Hospital and Kyushu University Hospital. Seven Fontan patients with DS were identified, and 35 Fontan patients without DS were recruited. During the mean observational periods of 14.7 years and 15.0 years (DS and non-DS, respectively) after the Fontan procedure, only one DS patient died. Central venous pressure (CVP) and transpulmonary pressure gradient significantly increased, and arterial oxygen saturation significantly decreased over time in DS patients after the Fontan procedure compared with those without DS. CVP in DS patients after the Fontan procedure increased over time compared with non-DS patients. Better management including the efficacy of Pulmonary arterial hypertension-specific therapy should be clarified in further studies.
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http://dx.doi.org/10.1007/s00246-021-02727-6DOI Listing
September 2021

Individual Differences in Conditioned Fear and Extinction in Female Rats.

Front Behav Neurosci 2021 18;15:740313. Epub 2021 Aug 18.

Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, United States.

The inability to extinguish a traumatic memory is a key aspect of post-traumatic stress disorder (PTSD). While PTSD affects 10-20% of individuals who experience a trauma, women are particularly susceptible to developing the disorder. Despite this notable female vulnerability, few studies have investigated this particular resistance to fear extinction observed in females. Similar to humans, rodent models of Pavlovian fear learning and extinction show a wide range of individual differences in fear learning and extinction, although female rodents are considerably understudied. Therefore, the present study examined individual differences in fear responses, including freezing behavior and ultrasonic vocalizations (USVs), of female Long-Evans rats during acquisition of fear conditioning and cued fear extinction. Similar to prior studies in males, female rats displayed individual variation in freezing during cued fear extinction and were divided into extinction competent (EC) and extinction resistant (ER) phenotypes. Differences in freezing between ER and EC females were accompanied by shifts in rearing during extinction, but no darting was seen in any trial. Freezing behavior during fear learning did not differ between the EC and ER females. Vocalizations emitted in the 22 and 50 kHz ranges during fear learning and extinction were also examined. Unlike vocalizations seen in previous studies in males, very few 22 kHz distress vocalizations were emitted by female rats during fear acquisition and extinction, with no difference between ER and EC groups. Interestingly, all female rats produced significant levels of 50 kHz USVs, and EC females emitted significantly more 50 kHz USVs than ER rats. This difference in 50 kHz USVs was most apparent during initial exposure to the testing environment. These results suggest that like males, female rodents show individual differences in both freezing and USVs during fear extinction, although females appear to vocalize more in the 50 kHz range, especially during initial periods of exposure to the testing environment, and emit very few of the 22 kHz distress calls that are typically observed in males during fear learning or extinction paradigms. Overall, these findings show that female rodents display fear behavior repertoires divergent from males.
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http://dx.doi.org/10.3389/fnbeh.2021.740313DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8418198PMC
August 2021

Efficacy of treat-and-repair strategy for atrial septal defect with pulmonary arterial hypertension.

Heart 2021 Jun 15. Epub 2021 Jun 15.

Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.

Objective: Therapeutic strategies for atrial septal defect (ASD) with severe pulmonary arterial hypertension (PAH) are controversial. This study aimed to evaluate the efficacy of PAH-specific medications and subsequent transcatheter closure (ie, treat-and-repair strategy) on clinical outcomes.

Methods: We enrolled 42 patients who were referred to 13 institutions for consideration of ASD closure with concomitant PAH and underwent the treat-and-repair strategy. The endpoint was cardiovascular death or hospitalisation due to heart failure or exacerbated PAH.

Results: At baseline prior to PAH-specific medications, pulmonary to systemic blood flow ratio (Qp:Qs), pulmonary vascular resistance (PVR), and mean pulmonary artery pressure (PAP) were 1.9±0.8, 6.9±3.2 Wood units and 45±15 mm Hg. Qp:Qs was increased to 2.4±1.2, and PVR and mean PAP were decreased to 4.0±1.5 Wood units and 35±9 mm Hg at the time of transcatheter ASD closure after PAH-specific medications. Transcatheter ASD closure was performed without any complications. During a median follow-up period of 33 months (1-126 months) after transcatheter ASD closure, one older patient died and one patient was hospitalised due to heart failure, but the other patients survived with an improvement in WHO functional class. PAP was further decreased after transcatheter ASD closure.

Conclusions: The treat-and-repair strategy results in low complication and mortality rates with a reduction in PAP in selected patients with ASD complicated with PAH who have a favourable response of medical therapy.
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http://dx.doi.org/10.1136/heartjnl-2021-319096DOI Listing
June 2021
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