Diastolic dysfunction and clinical outcomes after transcatheter or surgical aortic valve replacement in patients with atypical aortic valve stenosis.

BACKGROUND: Diastolic dysfunction is a predictor of poor outcomes in many cardiovascular conditions. At present, it is unclear whether diastolic dysfunction predicts adverse outcomes in patients with atypical aortic stenosis who undergo aortic valve replacement (AVR). METHODS: Five hundred and twenty-three patients who underwent transcatheter AVR (TAVR) (n = 303) and surgical AVR (SAVR) (n = 220) at a single institution were included in our analysis. Baseline left and right heart invasive hemodynamics were assessed. Baseline transthoracic echocardiograms were reviewed to determine aortic stenosis subtype and parameters of diastolic dysfunction. Aortic stenosis subtype was categorized as typical (normal flow, high-gradient) aortic stenosis, classical, low-flow, low-gradient (cLFLG) aortic stenosis, and paradoxical, low-flow, low-gradient (pLFLG) aortic stenosis. Cox proportional hazard models were utilized to examine the relation between invasive hemodynamic or echocardiographic variables of diastolic dysfunction, aortic stenosis subtype, and all-cause mortality. Propensity-score analysis was performed to study the relation between aortic stenosis subtype and the composite outcome [death/cerebrovascular accident (CVA)]. RESULTS: The median STS risk was 5.3 and 2.5% for TAVR and SAVR patients, respectively. Relative to patients with typical aortic stenosis, patients with atypical (cLFLG and pLFLG) aortic stenosis displayed a significantly higher prevalence of diastolic dysfunction (LVEDP ≥ 20mmHg, PCWP ≥ 20mmHg, echo grade II or III diastolic dysfunction, and echo-PCWP ≥ 20mmHg) and, independently of AVR treatment modality, had a significantly increased risk of death. In propensity-score analysis, patients with atypical aortic stenosis had higher rates of death/CVA than typical aortic stenosis patients, independently of diastolic dysfunction and AVR treatment modality. CONCLUSION: We demonstrate the novel observation that compared with patients with typical aortic stenosis, patients with atypical aortic stenosis have a higher burden of diastolic dysfunction. We corroborate the worse outcomes previously reported in atypical versus typical aortic stenosis and demonstrate, for the first time, that this observation is independent of AVR treatment modality. Furthermore, the presence of diastolic dysfunction does not independently predict outcome in atypical aortic stenosis regardless of treatment type, suggesting that other factors are responsible for adverse clinical outcomes in this higher risk cohort.

Comparison of Echocardiographic and Catheter Mean Gradient to Assess Stenosis After Transcatheter Aortic Valve Implantation.

Discordance exists between Doppler-derived and left heart catheterization (LHC)-derived mean gradient (MG) in transcatheter aortic valve implantation (TAVI). We compared echocardiographic parameters of prosthetic valve stenosis and LHC-derived MG in new TAVIs. In a retrospective, single-center study, intraoperative transesophageal echocardiogram (TEE)-derived MG, LHC-derived MG, and acceleration time (AT) were obtained before and after TAVI in 362 patients. Discharge MG, AT, and Doppler velocity index (DVI) using transthoracic echocardiogram (TTE) were also obtained. MG ≥10 mm Hg was defined as abnormal. During native valve assessment with pre-TAVI TEE and pre-TAVI LHC, Pearson correlation coefficient revealed a nearly perfect linear relation between both methods' MGs (r = 0.97, p <0.0001). Intraoperatively, after TAVI, Spearman correlation coefficient revealed a weak-to-moderate relation between post-TAVI TEE and LHC MGs (r = 0.33, p <0.0001). Significant differences were observed in categorizations between post-TAVI TEE MG and post-TAVI AT (McNemar test p = 0.0003) and between post-TAVI TEE MG and post-TAVI LHC MG (signed-rank test p <0.0001), with TEE MG more likely to misclassify a patient as abnormal. At discharge, 30% of patients had abnormal TTE MG, whereas 0% and 0.8% of patients had abnormal DVI and AT, respectively. Discharge TTE MG was not associated with death or hospitalization for heart failure at a median follow-up of 862 days. Post-TAVI Doppler-derived MG by intraoperative TEE was higher than LHC, despite being virtually identical before implantation. At discharge, patients were more likely to be classified as abnormal using MG than DVI and AT. Elevated MG at discharge was not associated with death or hospitalization for heart failure.

Semi-quantitative myocardial perfusion MRI in heart transplant recipients at rest: repeatability in healthy controls and assessment of cardiac allograft vasculopathy.

BACKGROUND: Cardiac Allograft Vasculopathy (CAV) is a major cause of chronic cardiac allograft failure. Invasive coronary angiography (ICA) and intravascular ultrasound (IVUS) are the current diagnostic methods. Myocardial perfusion MRI has become a promising non-invasive method to evaluate myocardial ischemia, but has not been thoroughly validated in CAV. Our objective was to assess the repeatability of myocardial rest-perfusion MRI in healthy volunteers and its feasibility in detecting CAV in transplant patients (Tx). METHODS: Twelve healthy volunteers and twenty transplant patients beyond the first year post- transplant underwent cardiac MRI at 1.5 T at rest including first-pass perfusion imaging in short axis (base, mid, apex) after injection of gadolinium. Volunteers underwent repeated cardiac MRI on different days (interval = 15.6 ± 2.4 days) to assess repeatability. Data analysis included semi-automatic contouring of endocardial and epicardial borders of the left ventricle (LV) and quantification of peak perfusion, time-to-peak (TTP) perfusion, and upslope of the perfusion curve. RESULTS: Between scans and re-scans in healthy volunteers, peak signal intensity, slope, and TTP demonstrated moderate agreement (ICC = 0.53, 0.48, and 0.59, respectively; all, p < .001). Peak signal intensity, slope, and TTP were moderately variable with COV values of 23%, 42%, and 35%, respectively. Peak perfusion was significantly reduced in CAV positive (n = 9 Tx patients) compared to CAV negative (n = 11 Tx patients) groups (90.7 ± 27.0 vs 139.5 ± 30.2, p < .001). CONCLUSION: Cardiac MRI is a moderately repeatable method for the semi-quantitative assessment of first-pass myocardial perfusion at rest. Semi-quantitative surrogate markers of LV perfusion could play a role in CAV detection.