Dobutamine Stress Echocardiography in Low-Gradient Aortic Stenosis.

IMPORTANCE: Guidelines recommend the use of Dobutamine stress echocardiography (DSE) in patients with low-gradient aortic stenosis (AS) and left ventricular ejection fraction (LVEF) <50%. However, a paucity exists in DSE data when LVEF>35%. OBJECTIVE: To examine the diagnostic accuracy of DSE, in patients with low-gradient AS with a wide range of LVEF and to examine the interaction between the diagnostic accuracy of DSE and LVEF. DESIGN, SETTING AND PARTICIPANTS: Patients with mean-gradient<40 mmHg, AVA<1.0 cm2, and stroke volume index≤35 mL/m2 undergoing DSE and Cardiac Computer Tomography (C-CT) were identified from three prospectively collected patient cohorts, and stratified according to LVEF; LVEF<35%, LVEF 35-50% & LVEF>50%. EXPOSURE: DSE and C-CT was performed on patients with low-gradient AS MAIN OUTCOMES AND MEASURES: Severe AS was defined as AVC score ≥2000 AU among men, and ≥1200 AU for women on C-CT. RESULTS: Of 221 patients included in the study, 78 (35%) presented with LVEF<35%, 67 (30%) with LVEF 35-50%, and 76 (34%) with LVEF>50%. Mean-gradient and Vmax during DSE showed significantly diagnostic heterogeneity between LVEF groups, being most precise when LVEF<35% (both AUC=0.90), albeit with optimal thresholds of 30 mmHg & 377 cm/s, and a limited diagnostic yield in patients with LVEF≥35% (AUC=0.67 & 0.66 in LVEF 35-50% and AUC=0.65 & 0.60 in LVEF≥50%). Using guideline thresholds led to a sensitivity/specificity of 49%/84% for all patients with LVEF<50%. CONCLUSION AND RELEVANCE: While DSE is safe and leads to an increase in stroke volume in patients with low-gradient AS regardless of LVEF, the association between DSE gradients and AS severity assessed by C-CT demonstrates important heterogeneity depending on LVEF, with highest accuracy in patients with LVEF<35%.

Aortic Valve Calcification Density Measured by MDCT in the Assessment of Aortic Stenosis Severity.

BACKGROUND: Aortic valve calcification (AVC) indexation to the aortic annulus (AA) area measured by Doppler echocardiography (AVCdEcho) provides powerful prognostic information in patients with aortic stenosis (AS). However, the indexation by AA measured by multidetector computed tomography (AVCdCT) has never been evaluated. The aim of this study was to compare AVC, AVCdCT, and AVCdEcho with regard to hemodynamic correlations and clinical outcomes in patients with AS. METHODS: Data from 889 patients, mainly White, with calcific AS who underwent Doppler echocardiography and multidetector computed tomography within the same episode of care were retrospectively analyzed. AA was measured both by Doppler echocardiography and multidetector computed tomography. AVCdCT severity thresholds were established using receiver operating characteristic curve analyses in men and women separately. The primary end point was the occurrence of all-cause mortality. RESULTS: Correlations between gradient/velocity and AVCd were stronger (both P≤0.005) using AVCdCT (r=0.68, P<0.001 and r=0.66, P<0.001) than AVC (r=0.61, P<0.001 and r=0.60, P<0.001) or AVCdEcho (r=0.61, P<0.001 and r=0.59, P<0.001). AVCdCT thresholds for the identification of severe AS were 334 Agatston units (AU)/cm2 for women and 467 AU/cm2 for men. On a median follow-up of 6.62 (6.19-9.69) years, AVCdCT ratio was superior to AVC ratio and AVCdEcho ratio to predict all-cause mortality in multivariate analyses (hazard ratio [HR], 1.59 [95% CI, 1.26-2.00]; P<0.001 versus HR, 1.53 [95% CI, 1.11-1.65]; P=0.003 versus HR, 1.27 [95% CI, 1.11-1.46]; P<0.001; all likelihood test P≤0.004). AVCdCT ratio was superior to AVC ratio and AVCdEcho ratio to predict survival under medical treatment in multivariate analyses (HR, 1.80 [95% CI, 1.27-1.58]; P<0.001 compared with HR, 1.55 [95% CI, 1.13-2.10]; P=0.007; HR, 1.28 [95% CI, 1.03-1.57]; P=0.01; all likelihood test P<0.03). AVCdCT ratio predicts mortality in all subgroups of patients with AS. CONCLUSIONS: AVCdCT appears to be equivalent or superior to AVC and AVCdEcho to assess AS severity and predict all-cause mortality. Thus, it should be used to evaluate AS severity in patients with nonconclusive echocardiographic evaluations with or without low-flow status. AVCdCT thresholds of 300 AU/cm2 for women and 500 AU/cm2 for men seem to be appropriate to identify severe AS. Further studies are needed to validate these thresholds, especially in diverse populations.

Low body mass index and risk of mortality after mitral transcatheter edge-to-edge repair procedure: The "obesity paradox".

BACKGROUND: Most patients undergoing the mitral transcatheter edge-to-edge repair (TEER) technique are elderly comorbid patients. Low body mass index (BMI) < 23 kg/m2 has been identified in other elderly populations as a risk factor, but has not been studied sufficiently in mitral TEER. AIMS: We aimed to study the impact of low BMI (23 kg/m2) on the outcome after mitral TEER. METHODS: Patients undergoing first-time TEER for mitral regurgitation at a single tertiary center were included, with the exclusion of patients with preprocedural hemodynamic instability or missing BMI. The primary endpoint was all-cause mortality. Secondary endpoints were long-term major bleeding or admission with heart failure. RESULTS: A total of 120 patients (mean age 76 ± 10 years, 76% men) were included in the study. Thirty-nine (31%) had low BMI. Patients with low BMI had a similar symptomatic benefit as patients with BMI ≥ 23 kg/m2 at 1 year regarding decrease in diuretics dose and decrease in New York Heart Association (NYHA) class (p > 0.05). In a multivariable Cox regression analysis, BMI as a continuous variable (hazard ratio [HR]: 0.93 [95% confidence interval, CI: 0.87-0.99], p = 0.03) and low BMI (HR: 1.99 [95% CI: 1.12-3.52], p = 0.02) were associated with the primary outcome. Low BMI was not significantly associated with major bleeding (subdistribution hazard ratio [SHR]: 2.39 [95% CI: 0.96-5.97], p = 0.06) or admission with heart failure (SHR: 1.06 [95% CI: 0.61-1.88], p = 0.83) during follow-up with univariable competing risk regression analysis. CONCLUSION: Low BMI is a risk factor for mortality after mitral valve TEER, confirming the presence of an "obesity paradox" in this population and should receive attention in patient selection.

Aortic Valvular Stenosis and Heart Failure: Advances in Diagnostic, Management, and Intervention.

Up to 30% of patients with aortic stenosis (AS) present with heart failure (HF) symptoms with either reduced or preserved left ventricular ejection fraction. Many of these patients present with a low-flow state, reduced aortic-valve-area (≤1.0 cm2) with low aortic-mean-gradient and aortic-peak-velocity (<40 mm Hg and <4.0 m/s). Thus, determination of true severity is essential for correct management, and multi-imaging evaluation must be performed. Medical treatment of HF is imperative and should be optimized concurrently with the determination of AS-severity. Finally, AS should be treated according to guidelines, keeping in mind that HF and low-flow increase interventions risks.

Hemodynamic changes during aortic valve surgery among patients with aortic stenosis.

Introduction. Patients with severe aortic stenosis (AS) undergoing surgery are at increased risk of hypotension and hypoperfusion. Although treatable with inotropic agents or fluid, little is known about how these therapies affect central hemodynamics in AS patients under general anesthesia. We measured changes in central hemodynamics after dobutamine infusion and fluid bolus among patients with severe AS and associated these changes with preoperative echocardiography. Methods. We included 33 patients with severe AS undergoing surgical AVR. After induction of general anesthesia, hemodynamic measurements were obtained with a pulmonary artery catheter, including Cardiac index (CI), stroke volume index (SVi) and pulmonary capillary wedge pressure (PCWP). Measurements were repeated during dobutamine infusion, after fluid bolus and lastly after sternotomy. Results. General anesthesia resulted in a decrease in CI and SVi compared to preoperative values. During dobutamine infusion CI increased but mean SVi did not (38 ± 12 vs 37 ± 13 ml/m2, p = .90). Higher EF and SVi before surgery and a larger decrease in SVi after induction of general anesthesia were associated with an increase in SVi during dobutamine infusion. After fluid bolus both CI, SVi (48 ± 12 vs 37 ± 13 ml/min/m2, p < .0001) and PCWP increased. PCWP increased mostly among patients with a larger LA volume index. Conclusion. In patients with AS, CI can be increased with both dobutamine and fluid during surgery. Dobutamine's effect on SVI was highly variable and associated with baseline LVEF, and an increase in CI was mostly driven by an increase in heart rate. Fluid increased SVi at the cost of an increase in PCWP.