Praveen Mehrotra

Differential left ventricular remodelling and longitudinal function distinguishes low flow from normal-flow preserved ejection fraction low-gradient severe aortic stenosis

AIMS There is uncertainty in identifying patients with severe aortic stenosis (AS) with preserved left ventricular (LV) ejection fraction, low flow, and low gradients (LFLG). Prior studies propose that these patients demonstrate significant concentric remodelling and decreased survival, while others suggest that they have features and survival similar to moderate AS. METHODS AND RESULTS We compared the clinical characteristics, echocardiographic features, and overall survival of LFLG AS patients (n = 38) to those with normal-flow, low-gradient (NFLG) severe AS (n = 75) and moderate AS (n = 70). Low-flow, low-gradient patients had the lowest end-diastolic volume index (43 vs. 54 vs. 54 mL/m², P < 0.001), highest relative wall thickness (RWT) (60 vs. 49 vs. 48%, P < 0.001), and lowest septal mitral annular displacement (1.0 vs. 1.5 vs. 1.5 cm, P < 0.001). New York Heart Association (NYHA) class III/IV symptoms were the most frequent in the LFLG group (29 vs. 11 vs. 3%, P < 0.001). Survival at 3 years was significantly lower in LFLG compared with NFLG (P = 0.006) and moderate AS (P = 0.002), but not different between NFLG and moderate AS (P = 0.49). Higher NYHA classification (HR 1.77, 95% CI 1.22-2.57), RWT > 50% (HR 3.28, 95% CI 1.33-8.1), and septal displacement <1.1 cm (HR 3.93, 95% CI 1.96-7.82) but not low flow were independent predictors of survival in Cox proportional hazards analysis. CONCLUSION Preserved ejection fraction, LFLG AS patients exhibit marked concentric remodelling and impaired longitudinal functional-features that predict their poor long-term survival. Normal-flow, low-gradient AS patients have outcomes similar to moderate AS.

First experience with transcatheter valve-in-valve implantation for a stenotic mitral prosthesis within the United States.

A 72-year-old woman with coronary artery bypass graft surgery (CABG) with mitral valve replacement (MVR) using a 27-mm Carpentier-Edwards bioprosthesis (Edwards Lifesciences, Irvine, California) 6 years earlier was referred to our institution with severe, symptomatic prosthetic valve mitral stenosis

Differential Effects of Dobutamine Versus Treadmill Exercise on Left Ventricular Volume and Wall Stress

BACKGROUND Dobutamine and exercise echocardiography are well-validated modalities used for the evaluation of patients with suspected myocardial ischemia. Patients undergoing dobutamine stress echocardiography (DSE), however, experience less angina, ST-segment depressions, and wall motion abnormalities. Other than the effect on heart rate, the physiologic and volumetric differences between pharmacologic and exercise-induced stress that affect myocardial oxygen demand are not well defined. The aim of this study was to test the hypothesis that in the absence of ischemia, dobutamine reduces left ventricular (LV) volume, wall tension (WTN), and peak systolic stress (PSS) compared with exercise. METHODS Seventy patients without ischemia were prospectively enrolled (35 underwent exercise echocardiography and 35 DSE), and various hemodynamic parameters were measured and LV volumes calculated (using the Simpson and Teichholz formulas). Systolic WTN and PSS were determined at rest and stress. RESULTS LV end-diastolic volume index fell significantly more with dobutamine than with exercise (-34% vs -9%, P < .0001), as did mean end-systolic volume index (-55% vs -37%, P = .07). Systolic blood pressure increased more with exercise (41 ± 22 vs 1 ± 33 mm Hg, P < .0001), as did cardiac index (2.5 ± 0.7 vs 1.0 ± 0.8 L/min/m(2), P < .0001). Systolic WTN increased with exercise by 24% (P < .0001) but decreased with dobutamine by 18% (P < .0001). PSS increased with exercise by 21% (P < .0001) but decreased with dobutamine by 23% (P < .0001). CONCLUSIONS The degree of stress achieved with DSE appears to be considerably different than with exercise. DSE produces greater reductions in LV end-diastolic and end-systolic volumes than exercise and decreases rather than increases in WTN and PSS. The lower WTN and PSS were related to both a decrease in LV volume and lower systolic blood pressure with dobutamine. These observations support recommendations favoring exercise stress testing in patients able to exercise and reinforce the notion that high-risk echocardiographic features of ischemia such as stress-induced LV dilatation may be less striking or absent with DSE.

Risk Prediction in Aortic Valve Replacement: Incremental Value of the Preoperative Echocardiogram

Background Risk prediction is a critical step in patient selection for aortic valve replacement (AVR), yet existing risk scores incorporate very few echocardiographic parameters. We sought to evaluate the incremental predictive value of a complete echocardiogram to identify high‐risk surgical candidates before AVR. Methods and Results A cohort of patients with severe aortic stenosis undergoing surgical AVR with or without coronary bypass was assembled at 2 tertiary centers. Preoperative echocardiograms were reviewed by independent observers to quantify chamber size/function and valve function. Patient databases were queried to extract clinical data. The cohort consisted of 432 patients with a mean age of 73.5 years and 38.7% females. Multivariable logistic regression revealed 3 echocardiographic predictors of in‐hospital mortality or major morbidity: E/e’ ratio reflective of elevated left ventricular (LV) filling pressure; myocardial performance index reflective of right ventricular (RV) dysfunction; and small LV end‐diastolic cavity size. Addition of these echocardiographic parameters to the STS risk score led to an integrated discrimination improvement of 4.1% (P<0.0001). After a median follow‐up of 2 years, Cox regression revealed 5 echocardiographic predictors of all‐cause mortality: small LV end‐diastolic cavity size; LV mass index; mitral regurgitation grade; right atrial area index; and mean aortic gradient <40 mm Hg. Conclusions Echocardiographic measures of LV diastolic dysfunction and RV performance add incremental value to the STS risk score and should be integrated in prediction when evaluating the risk of AVR. In addition, findings of small hypertrophied LV cavities and/or low mean aortic gradients confer a higher risk of 2‐year mortality.

Clinical features and prognosis of patients with isolated severe aortic stenosis and valve area less than 1.0 cm2

Objective Current guidelines define severe aortic stenosis (AS) as an aortic valve area (AVA)≤1.0 cm2, but some authors have suggested that the AVA cut-off be decreased to 0.8 cm2. The aim of this study was, therefore, to better describe the clinical features and prognosis of patients with an AVA of 0.8–0.99 cm2. Methods Patients with isolated, severe AS and ejection fraction ≥55% with an AVA of 0.8–0.99 cm2 (n=105) were compared with those with an AVA<0.8 cm2 (n=155) and 1.0–1.3 cm2 (n=81). The endpoint of this study was a combination of death from any cause or aortic valve replacement at or before 3 years. Results Patients with an AVA of 0.8–0.99 cm2 group comprised predominantly normal-flow, low-gradient (NFLG) AS, while high gradients and low flow were more often observed with an AVA<0.8 cm2. The frequency of symptoms was not significantly different between an AVA of 0.8–0.99 cm2 and 1.0–1.3 cm2. The combined endpoint was achieved in 71%, 52% and 21% of patients with an AVA of 0.8 cm2, 0.8–0.99 cm2and 1.0–1.3 cm2, respectively (p<0.001). Among patients with an AVA of 0.8–0.99 cm2, NFLG AS was associated with a lower hazard (HR=0.40, 95% CI 0.23 to 0.68, p=0.001) of achieving the combined endpoint with outcomes similar to moderate AS in the first 1.5 years of follow-up. Patients with high-gradient or low-flow AS with an AVA of 0.8–0.99 cm2 had outcomes similar to those with an AVA<0.8 cm2. The sensitivity for the combined endpoint was 61% for an AVA cut-off of 0.8 cm2 and 91% for a cut-off of 1.0 cm2. Conclusions The outcomes of patients with AS with an AVA of 0.8–0.99 cm2 are variable and are more precisely defined by flow-gradient status. Our findings support the current AVA cut-off of 1.0 cm2.

Automated and Manual Measurements of the Aortic Annulus with ECG-Gated Cardiac CT Angiography Prior to Transcatheter Aortic Valve Replacement: Comparison with 3D-Transesophageal Echocardiography

RATIONALE AND OBJECTIVES Multimodality evaluation of the aortic annulus is generally advocated to plan for transcatheter aortic valve replacement (TAVR). We compared aortic annular measurements by cardiac computed tomography angiography (cCTA) to three-dimensional transesophageal echocardiography (3D-TEE), and also evaluated the use of semi-automated software for cCTA annular measurements. MATERIALS AND METHODS A retrospective cohort of 74 patients underwent 3D-TEE and electrocardiogram-gated cCTA of the heart within 30 days for TAVR planning. 3D-TEE measurements were obtained during mid-systole; cCTA measurements were obtained during late-systole (40% of R-R interval) and mid-diastole (80% of R-R interval). Annular area was measured independently by manual planimetry and with semi-automated software. RESULTS cCTA measurements in systole and diastole were highly correlated for short-axis diameter (r = 0.91), long-axis diameter (r = 0.92), and annular area (r = 0.96), although systolic measurements were significantly larger (P < 0.001), most notably for the short-axis diameter. Good correlation was observed between 3D-TEE and cCTA for short-axis diameter (r = 0.84-0.90), long-axis diameter (r = 0.77-0.79), and annular area (r = 0.89-0.90). As compared to 3D-TEE, annular area is overmeasured by 28 mm2 on systolic phase cCTA (P < 0.008), but nearly identical with 3D-TEE on diastolic phase cCTA. Semi-automated and manual cCTA annulus measurements were highly correlated in systole (r = 0.94) and diastole (r = 0.93), although the semi-automated annular area measured 11-30 mm2 greater than manual planimetry. Of note, the 95% limits of agreement in our Bland-Altman analysis suggest that the variability in annular area estimates for individual patients between cCTA and 3D-TEE (-100.9 to 99.6 mm2), as well as the variability between manual and automated measurements with cCTA (-105.9 to 45.2 mm2), may be sufficient to alter size selection for an aortic prosthesis. CONCLUSIONS Although all cCTA measurements are highly correlated with measurements by 3D-TEE, diastolic phase cCTA measurements tend to be closer to standard mid-systolic 3D-TEE measurements. Semi-automated measurement of the aortic annulus with cCTA is highly correlated with manual planimetry. Nonetheless, annular contours derived by semi-automated software should be visually inspected, as the variability in area estimates for individual cases between manual and automated measurements may alter the sizing of an aortic prosthesis.

Recent Technological Advancements in Cardiac Ultrasound Imaging

HighlightsRecent technological advancements in the field of cardiac ultrasound are reviewed.Contrast echocardiography has become an established practice in cardiac ultrasound.Standardization will translate these advancements for clinical cardiac imaging. ABSTRACT About 92.1 million Americans suffer from at least one type of cardiovascular disease. Worldwide, cardiovascular diseases are the number one cause of death (about 31% of all global deaths). Recent technological advancements in cardiac ultrasound imaging are expected to aid in the clinical diagnosis of many cardiovascular diseases. This article provides an overview of such recent technological advancements, specifically focusing on tissue Doppler imaging, strain imaging, contrast echocardiography, 3D echocardiography, point‐of‐care echocardiography, 3D volumetric flow assessments, and elastography. With these advancements ultrasound imaging is rapidly changing the domain of cardiac imaging. The advantages offered by ultrasound imaging include real‐time imaging, imaging at patient bed‐side, cost‐effectiveness and ionizing‐radiation‐free imaging. Along with these advantages, the steps taken towards standardization of ultrasound based quantitative markers, reviewed here, will play a major role in addressing the healthcare burden associated with cardiovascular diseases.

LOW STROKE VOLUME IN PATIENTS WITH SEVERE AORTIC STENOSIS IS ASSOCIATED WITH ADVERSE LEFT VENTRICULAR REMODELING

The degree of left ventricular (LV) remodeling due to pressure overload varies significantly in patients with severe aortic stenosis (AS). Worsening compensatory adaptation of the left ventricle to pressure load may be manifested by differences in LV remodeling which results in decreased stroke

RIGHT VENTRICULAR FRACTIONAL AREA CHANGE PREDICTS INVASIVELY-DETERMINED HEMODYNAMICS IN PATIENTS WITH PULMONARY ARTERIAL HYPERTENSION

Evaluation of the right heart is critical in patients with pulmonary arterial hypertension (PAH). However, in many echocardiography laboratories this evaluation remains qualitative in nature. We sought to determine which quantitative right heart parameters by echocardiography were predictive of

A narrow complex tachycardia with varying RP intervals: What is the mechanism?

Case presentation A 54-year-old woman underwent diagnostic electrophysiological study because of recurrent symptomatic narrow complex tachycardia (NCT) and intolerance to metoprolol therapy. Baseline atrio-His and His-ventricular intervals measured 116 and 37 ms, respectively. Dual antegrade atrioventricular (AV) nodal physiology was observed during programmed atrial extrastimulation. Ventriculoatrial conduction was decremental and concentric (earliest at the anteroseptum). Her clinical tachycardia (Figure 1A) was repeatedly induced by rapid atrial pacing. Attempt to entrain tachycardia from the ventricle is shown in Figure 1B. Figures 2A and 2B show the response of tachycardia to atrial premature depolarization (APD) and overdrive pacing from the coronary sinus (CS), respectively. Figure 3 shows tachycardia before ablation. Based on these observations, what is the mechanism of tachycardia?