Citations

ABSTRACT The adult zebrafish is an emerging vertebrate model for studying human cardiomyopathies; however, whether the simple zebrafish heart can model different subtypes of cardiomyopathies, such as dilated cardiomyopathy (DCM), remains elusive. Here, we generated and characterized an inherited DCM model in adult zebrafish and used this model to search for therapeutic strategies. We employed transcription activator-like effector nuclease (TALEN) genome editing technology to generate frame-shift mutants for the zebrafish ortholog of human BCL2-associated athanogene 3 (BAG3), an established DCM-causative gene. As in mammals, the zebrafish bag3 homozygous mutant (bag3e2/e2) exhibited aberrant proteostasis, as indicated by impaired autophagy flux and elevated ubiquitinated protein aggregation. Through comprehensive phenotyping analysis of the mutant, we identified phenotypic traits that resembled DCM phenotypes in mammals, including cardiac chamber enlargement, reduced ejection fraction characterized by increased end-systolic volume/body weight (ESV/BW), and reduced contractile myofibril activation kinetics. Nonbiased transcriptome analysis identified the hyperactivation of the mechanistic target of rapamycin (mTOR) signaling in bag3e2/e2 mutant hearts. Further genetic studies showed that mtorxu015/+, an mTOR haploinsufficiency mutant, repaired abnormal proteostasis, improved cardiac function and rescued the survival of the bag3e2/e2 mutant. This study established the bag3e2/e2 mutant as a DCM model in adult zebrafish and suggested mtor as a candidate therapeutic target gene for BAG3 cardiomyopathy.

The clinical, educational, and research facets of lung transplantation have advanced significantly since the first lung transplant in 1963. The formation of the International Society for Heart and Lung Transplantation (ISHLT) and subsequent Registry has forged a precedent of collaborative teamwork that has significantly affected current lung transplantation outcomes. The Society for the Advancement of Anesthesia (SATA) is dedicated to developing educational platforms for all facets of transplant anesthesia. Additionally, we believe that the anesthetic training for lung transplantation has not kept pace with other advances in the field. As such, SATA presents for consideration these educational milestones and competencies for anesthetic fellowship training in the field of lung transplantation. The proposed milestones were designed on the framework of 6 core competencies created by the Accreditation Council on Graduate Medical Education. The milestones were identified by combining the expert opinion of our Thoracic Transplant Committee, our experience as educators, and literature review. We offer this White Paper to the anesthesiology and transplant communities as a starting point for the discussion and evolution of perioperative anesthetic care in the field of lung transplantation.

Objective The hypertrophic cardiomyopathy (HCM) risk-sudden cardiac death (SCD) calculator endorsed by the 2014 European Society of Cardiology has not been independently validated in the Asians. We aimed to investigate whether the HCM Risk-SCD calculator effectively predicts SCD in Korean HCM population. Methods An observational, longitudinal cohort study was performed in 730 patients with HCM from 2007 to 2017. The primary endpoint was a composite of SCD and appropriate implantable cardioverter-defibrillator (ICD) therapy. Results During a follow-up period of 4288 person-years, 16 (2.2%) patients reached the primary endpoint. This validation study revealed a calibration slope of 0.892 and C-statistics of 0.718. The primary endpoint occurred in 1.1% (7/615), 4.6% (3/65) and 12.0% (6/50) of low-risk, intermediate-risk and high-risk groups, respectively. Although most patients (85.2%) without the primary endpoint were classified into the low-risk group, 7 of 11 SCD (63.6%) occurred in the low-risk group. In univariable and multivariable analysis, sex (woman) was significantly associated with the primary endpoint and emerged as independent predictor. The addition of sex to the HCM Risk-SCD calculator significantly improved the predictive value of the primary endpoint (net reclassification improvement 0.557, p=0.015). Conclusions In the Korean HCM population, the HCM Risk-SCD calculator had a high negative predictive value and accuracy for predicting SCD or appropriate ICD therapy, but misclassified a few patients experiencing the primary endpoint as low-risk or intermediate-risk groups.

AbstractBackgroundRecipients of implantable cardioverter defibrillator (ICD) generator replacement with multiple medical comorbidities may be at higher risk of adverse outcomes that attenuate the benefit of ICD replacement. The aim of this investigation was to study the association between the Charlson comorbidity index (CCI) and outcomes after ICD generator replacement.MethodsAll patients undergoing first ICD generator replacement at Mayo Clinic, Rochester and Beth Israel Deaconess Medical Center, Boston between 2001 and 2011 were identified. Outcomes included: (a) all‐cause mortality, (b) appropriate ICD therapy, and (c) death prior to appropriate therapy. Multivariable Cox regression analysis was performed to assess association between CCI and outcomes.ResultsWe identified 1421 patients with mean age of 69.6 ± 12.1 years, 81% male and median (range) CCI of 3 (0‐18). During a mean follow‐up of 3.9 ± 3 years, 52% of patients died, 30.6% experienced an appropriate therapy, and 23.6% died without experiencing an appropriate therapy. In multivariable analysis, higher CCI score was associated with increased all‐cause mortality (Hazard ratio, HR 1.10 [1.06‐1.13] per 1 point increase in CCI, P < .001), death without prior appropriate therapy (HR 1.11 [1.07‐1.15], P < .0001), but not associated with appropriate therapy (HR 1.01 [0.97‐1.05], P = .53). Patients with CCI ≥5 had an annual risk of death of 12.2% compared to 8.7% annual rate of appropriate therapy.ConclusionsCCI is predictive of mortality following ICD generator replacement. The benefit of ICD replacement in patients with CCI score ≥5 should be investigated in prospective studies.

Background and Purpose— Hypertrophic cardiomyopathy patients with atrial fibrillation are at increased risk of stroke, and anticoagulation is strongly recommended. However, limited data are available regarding the safety and effectiveness of non–vitamin K antagonist oral anticoagulants (NOACs) for primary prevention of stroke. Methods— Using the Korean Health Insurance Review and Assessment Service database, we identified 2397 patients with hypertrophic cardiomyopathy and nonvalvular atrial fibrillation on oral anticoagulation from 2013 to 2016 without history of ischemic stroke, intracranial hemorrhage (ICH), or gastrointestinal bleeding (992 on warfarin and 1405 on NOACs). Inverse probability of treatment weighting with propensity scores was used to balance covariates between treatment groups. Risk for ischemic stroke, ICH, gastrointestinal bleeding, death, and their composite outcome associated with NOAC use was assessed with warfarin use as the reference. Results— During a mean follow-up of 1.6 years, the incidence rates of ischemic stroke, ICH, gastrointestinal bleeding, death, and composite outcome were all significantly lower in the NOAC than in the warfarin group (stroke, 2.8 versus 5.0; ICH, 0.5 versus 1.3; gastrointestinal bleeding, 2.3 versus 3.0; death, 3.0 versus 5.1; composite, 7.5 versus 12.5 events per 100 person-years). NOACs were associated with significantly lower risks of ischemic stroke (hazard ratio [HR], 0.47; 95% CI, 0.32–0.68), ICH (HR, 0.31; 95% CI, 0.14–0.69), gastrointestinal bleeding (HR, 0.62; 95% CI, 0.40–0.96), death (HR, 0.45; 95% CI, 0.31–0.65), and the composite outcome (HR, 0.48; 95% CI, 0.38–0.61) than warfarin. The same trend was observed regardless of the NOAC dose and across various high-risk subgroups. In analysis of individual NOACs, all NOACs were associated with lower risks of ischemic stroke and composite outcome. Conclusions— NOACs showed superior effectiveness and safety versus warfarin in the primary prevention of stroke versus warfarin in real-world Asian hypertrophic cardiomyopathy with atrial fibrillation.

Abstract Aims Native T1 times from T1 mapping cardiac magnetic resonance (CMR) are associated with myocardial fibrosis in aortic stenosis (AS). We investigated whether changing patterns in native T1 predict clinical outcomes after aortic valve replacement (AVR) in severe AS patients. Methods and results Forty-three patients with severe AS (65.9 ± 8.1 years; 24 men) who underwent T1 mapping CMR at baseline and 1 year after AVR were prospectively enrolled. Upper limit of native T1 from healthy volunteers was used to define normal myocardium and diffuse fibrosis (native T1 &lt; 1208.4 and ≥1208.4 ms, respectively). Participants were categorized into Group 1 (pre- and post-AVR normal myocardium; n = 11), Group 2 (pre-AVR diffuse fibrosis and post-AVR normal myocardium; n = 18), and Group 3 (post-AVR diffuse fibrosis; n = 14). Native T1 significantly decreased 1 year after AVR (pre-AVR, 1233.8 ± 49.7 ms; post-AVR, 1189.1 ± 58.4 ms; P &lt; 0.001), which was associated with left ventricular (LV) mass regression (△native T1 vs. △LV mass index, r = 0.454, P = 0.010) and systolic function improvement (△native T1 vs. △LV ejection fraction, r = −0.379, P = 0.012). Group 2 showed greater functional improvements, whereas these benefits were blunted in Group 3. Group 3 had significantly worse outcomes than Group 1 [hazard ratio (HR), 9.479, 95% confidence interval (CI) 1.176–76.409; P = 0.035] and Group 2 (HR 3.551, 95% CI 1.178–10.704; P = 0.024). Conclusion AVR-induced changes in native T1 values are associated with LV systolic functional changes as well as prognosis in severe AS. Post-AVR T1 mapping CMR can be used as an imaging biomarker.

Objective The aim of this study was to determine if computed tomography (CT) angiography using an individualized transition delay (CTA-ID) would facilitate reductions in injection rate and iodine dose. Methods The CTA-ID was performed in 20 patients with routine injection rate and iodine dose; 20 patients with injection rate lowered by 1 mL/s; and 40 patients with injection rate lowered by 1 mL/s with 29% less iodine. Routine CTAs in the same or size-matched patients served as controls. Diagnostic image quality and intra-arterial CT numbers were assessed. Results The median transition delay between aortic threshold and CTA-ID image acquisition was significantly longer than with conventional bolus tracking (mean increase, 13.3 seconds; P < 0.0001), with image quality being the same or better. Intra-arterial CT numbers were 200 Hounsfield units or greater for 80 of 80 CTA-ID, but not for 6 of 49 (12%) internal control or for 11 of 80 (14%) size-matched control patients. Conclusion The CTA-ID bolus-tracking software alters transition delays to permit diagnostic CTA examinations despite slower injection rate and less iodine.

Cholangiocarcinoma (CCA) is the second most common malignancy arising in the liver. It carries a poor prognosis, in part because its pathogenesis is not well understood. The type 3 inositol 1,4,5‐trisphosphate receptor (ITPR3) is the principal intracellular calcium ion (Ca2+) release channel in cholangiocytes, and its increased expression has been related to the pathogenesis of malignancies in other types of tissues, so we investigated its role in CCA. ITPR3 expression was increased in both hilar and intrahepatic CCA samples as well as in CCA cell lines. Deletion of ITPR3 from CCA cells impaired proliferation and cell migration. A bioinformatic analysis suggested that overexpression of ITPR3 in CCA would have a mitochondrial phenotype, so this was also examined. ITPR3 normally is concentrated in a subapical region of endoplasmic reticulum (ER) in cholangiocytes, but both immunogold electron microscopy and super‐resolution microscopy showed that ITPR3 in CCA cells was also in regions of ER in close association with mitochondria. Deletion of ITPR3 from these cells impaired mitochondrial Ca2+ signaling and led to cell death. Conclusion: ITPR3 expression in cholangiocytes becomes enhanced in CCA. This contributes to malignant features, including cell proliferation and migration and enhanced mitochondrial Ca2+ signaling.