Accuracy of dobutamine echocardiography for detection of myocardial viability in patients with an occluded left anterior descending coronary artery

Objectives.We studied the accuracy of dobutamine echocardiography for the detection of myocardial viability in patients with an occluded left anterior descending coronary artery and regional ventricular dysfunction.Background.Contractile reserve during dobutamine echocardiography is an accurate marker of myocardial viability in patients with coronary stenoses and ventricular dysfunction. However, its accuracy in patients with an occluded vessel has not been evaluated.Methods.We studied 41 patients with >50% stenosis of the left anterior descending coronary artery and regional ventricular dysfunction who underwent dobutamine echocardiography for detection of viable myocardium. Contractile reserve was defined as improvement in wall motion score of two or more contiguous septal or anterior segments during dobutamine echocardiography. Recovery of function was defined as improvement in rest wall motion score of two or more contiguous segments after revascularization.Results.Patients were classified into two groups according to the presence (n = 20) or absence (n = 21) of left anterior descending coronary artery occlusion. Contractile reserve was detected in 40% of patients with an occluded and 43% with a nonoccluded artery (p = 0.8). Of 41 patients, 27 underwent revascularization, 12 with and 15 without an occluded vessel. Recovery of function occurred in 6 (50%) of 12 patients in the occluded artery group and in 5 (33%) of 15 in the nonoccluded artery group (p = 0.4). Among patients with an occluded artery, the positive and negative predictive values of dobutamine echocardiography for recovery of function were 100% (95% confidence interval [CI] 48% to 100%) and 86% (95% CI 42% to 100%), respectively.Conclusions.Our results indicate that contractile reserve during dobutamine echocardiography can be detected in patients with an occluded vessel and may be useful for predicting recovery of function after revascularization

Assessment of aortic regurgitation by transesophageal color Doppler imaging of the vena contracta: validation against an intraoperative aortic flow probe

AbstractOBJECTIVESThis study was performed to validate the accuracy of color flow vena contracta (VC) measurements of aortic regurgitation (AR) severity by comparing them to simultaneous intraoperative flow probe measurements of regurgitant fraction (RgF) and regurgitant volume (RgV).BACKGROUNDColor Doppler imaging of the vena contracta has emerged as a simple and reliable measure of the severity of valvular regurgitation. This study evaluated the accuracy of VC imaging of AR by transesophageal echocardiography (TEE).METHODSA transit-time flow probe was placed on the ascending aorta during cardiac surgery in 24 patients with AR. The flow probe was used to measure RgF and RgV simultaneously during VC imaging by TEE. Flow probe and VC imaging were interpreted separately and in blinded fashion.RESULTSA good correlation was found between VC width and RgF (r = 0.85) and RgV (r = 0.79). All six patients with VC width >6 mm had a RgF >0.50. All 18 patients with VC width <5 mm had a RgF <0.50. Vena contracta area also correlated well with both RgF (r = 0.81) and RgV (r = 0.84). All six patients with VC area >7.5 mm2had a RgF >0.50, and all 18 patients with a VC area <7.5 mm2had a RgF <0.50. In a subset of nine patients who underwent afterload manipulation to increase diastolic blood pressure, RgV increased significantly (34 ± 26 ml to 41 ± 27 ml, p = 0.042) while VC width remained unchanged (5.4 ± 2.8 mm to 5.4 ± 2.8 mm, p = 0.41).CONCLUSIONSVena contracta imaging by TEE color flow mapping is an accurate marker of AR severity. Vena contracta width and VC area correlate well with RgF and RgV obtained by intraoperative flow probe. Vena contracta width appears to be less afterload-dependent than RgV

Improved left ventricular contractility with cool temperature hemodialysis

Improved left ventricular contractility with cool temperature hemodialysis. Cool temperature dialysis (CTD) has been shown to sharply decrease the frequency of intradialytic hemodialysis hypotension, but the mechanism of this hemodynamic protection is unknown. Therefore, we performed two-dimensional echocardiographic studies of left ventricular contractility in six stable hemodialysis patients before and after hemodialysis at 37°C (RTD) and 35°C (CTD). Left ventricular function was assessed by plotting the rate-corrected velocity of circumferential fiber shortening (Vcfc) against end-systolic wall stress (σes) at four different levels of afterload. Linear regression was used to calculate Vcfc at a common afterload of 50 g/cm2. Changes in weight and dialysis parameters were similar following RTD and CTD. Mean arterial pressure and heart rate did not change significantly following RTD or CTD. The Vcfc – σes relation was shifted upward in each patient after CTD, indicating increased contractility as compared to RTD or pre-dialysis baseline. Pre-dialysis Vcfc at an afterload of 50 g/cm2 was similar during RTD and CTD (0.94 ± 0.24 circ/sec vs. 0.92 ± 0.22 circ/sec). Post-dialysis Vcfc at an afterload of 50 g/cm2 was significantly higher for CTD than for RTD (1.13 ± 0.29 circ/sec vs. 0.98 ± 0.30 circ/sec, P = 0.0004). Thus, cool temperature dialysis increases left ventricular contractility in hemodialysis patients, which may be a potential mechanism whereby hemodynamic tolerance to the dialysis procedure is improved

Administration of an intravenous perfluorocarbon contrast agent improves echocardiographic determination of left ventricular volumes and ejection fraction: comparison with cine magnetic resonance imaging

AbstractObjectives. The purpose of this study was to determine whether contrast-enhanced transthoracic echocardiography improves the evaluation of left ventricular (LV) volumes and ejection fraction (EF).Background. Echocardiographic assessment of LV volumes and EF is widely used but may be inaccurate when the endocardium is not completely visualized. Recently the intravenous (IV) administration of perfluorocarbon microbubbles has been shown to enhance opacification of the LV cavity, but the utility of these agents to improve the echocardiographic assessment of LV systolic function is unknown.Methods. In 40 subjects (29 men and 11 women, aged 24 to 81 years) an assessment of LV volumes and EF was performed with a magnetic resonance imaging examination, followed immediately by a transthoracic echocardiogram before and after the intravenous administration of 2% dodecafluoropentane emulsion (EchoGen; Sonus Pharmaceuticals, Bothell, Washington).Results. Contrast enhanced the echocardiographic assessment of LV end diastolic volume (p < 0.02), end systolic volume (p < 0.01) and LVEF (p < 0.03). The percentage of subjects in whom the correct echocardiographic classification EF was normal, mild to moderately depressed or severely reduced improved significantly after contrast enhancement (from 71% before contrast to 94% after, p < 0.03). These findings were most striking in the subjects with two or more adjacent endocardial segments not visualized at baseline.Conclusions. Administration of an intravenous contrast agent improves the ability to accurately assess LV volumes and EF in humans. Contrast enhancement is most useful in subjects with two or more adjacent endocardial segments not seen at baseline

Clinical Relevance of Baseline TCP in Transcatheter Aortic Valve Replacement

AIMS: To investigate the influence of baseline thrombocytopenia (TCP) on short-term and long-term outcomes after transcatheter aortic valve replacement (TAVR). METHODS AND RESULTS: A total of 732 consecutive patients with severe, symptomatic aortic stenosis undergoing TAVR from January 2012 to December 2015 were included. Primary outcomes of interest were the relationship of baseline TCP with 30-day and 1-year all-cause mortality. Secondary outcomes of interest were procedural complications and in-hospital mortality in the same subgroups. The prevalence of TCP (defined as platelet count <150 × 109/L) at baseline was 21.9%, of whom 4.0% had moderate/severe TCP (defined as platelet count <100 × 109/L). Compared to no or mild TCP, moderate/severe TCP at baseline was associated with a significantly higher 30-day mortality (23.3% vs 2.3% and 3.1%, respectively; P<.001) and 1-year mortality (40.0% vs 8.3% and 13.4%, respectively; P<.001). In Cox regression analysis, moderate/severe baseline TCP was an independent predictor of 30-day and 1-year mortality (hazard ratio [HR], 13.18; 95% confidence interval [CI], 4.49-38.64; P<.001 and HR, 5.90; 95% CI, 2.68-13.02; P<.001, respectively). CONCLUSIONS: In conclusion, baseline TCP is a strong predictor of mortality in TAVR patients, possibly identifying a specific subgroup of frail patients; therefore, it should be taken into account when addressing TAVR risk

Assessment of the Severity of Paravalvular Regurgitation and its Role on Survival After Transcatheter Aortic Valve Replacement

Background: To evaluate the impact of various measurements of paravalvular regurgitation (PVR) on survival after transcatheter aortic valve replacement (TAVR). PVR can be difficult to grade and both its incidence and impact on survival may be decreasing as TAVR evolves. Methods: This retrospective study included 911 patients undergoing TAVR in two institutions. PVR was graded according to the 3-grade scheme proposed by the guidelines (PVR grade), and subsequently grade 2 and 3, and grade 0 and 1 were lumped together. PVR was also graded as a composite score (PVR score), based on 6 commonly used metrics. PVR grade, PVR score and its six individual components were tested against the risk of both 1-year and longer term mortality after TAVR. Results: Patients with moderate/severe PVR had a higher Society of Thoracic Sugeons (STS) score, higher levels of serum creatinine and larger left atria compared to patients with none/mild PVR. Moderate/severe PVR was more frequent with self-expandable and larger valves. After adjusting for American College of Cardiology (ACC) TAVR risk score, neither PVR grade, PVR score nor its six components were associated with an increased risk of mortality at 1-year (severe PVR adjusted HR: 0.75, 95% Confidence Interval [CI]: 0.19, 3.01, p = 0.50). However, intervention for clinically severe PVR increased the risk of mortality by more than 7-fold (adjusted hazard ratio [HR]: 7.6, 95% CI: 2.4, 23.5, p < 0.0001). Conclusions: In the contemporary era, moderate-severe PVR is uncommon. However, re-intervention for PVR portends a poor prognosis. This highlights the crucial importance of clinical judgment over imaging alone

Quantitative assessment of mitral regurgitation by doppler color flow imaging: Angiographic and hemodynamic correlations

AbstractThis study was performed to test the hypothesis that measurements of jet area by Doppler color flow imaging can predict the angiographic severity and hemodynamic consequences of mitral regurgitation. Doppler color flow imaging was performed in 47 patients undergoing cardiac catheterization and left ventriculography. The jet area was measured as the largest clearly definable flow disturbance in the parasternal and apical views, and expressed as the maximal jet area, the mean of the largest jet area (average jet area) in two views or as the ratio of these measures to left atrial area.Correlation of all Doppler color flow measurements with angiographic grades of mitral regurgitation were comparable, maximal jet area being closest at r = 0.76. A maximal jet area >8 cm2predicted severe mitral regurgitation with a sensitivity of 82% and specificity of 94%, whereas a maximal jet area <4 cm2predicted mild mitral regurgitation with a sensitivity and specificity of 85% and 75%, respectively. All patients with an average jet area >8 cm2manifested severe mitral regurgitation. However, jet area measurements showed limited correlation with regurgitant volume and fraction (r = 0.55 and 0.62, respectively) for maximal jet area, and were not predictive of hemodynamic abnormalities, including those of pulmonary wedge pressure, stroke volume or ventricular volumes.Thus, in patients with mitral regurgitation, maximal jet area from Doppler color flow imaging provides a simple measurement that predicts angiographic grade, but manifests a weak correlation with regurgitant volume and does not predict hemodynamic dysfunction

Does Digoxin Provide Additional Hemodynamic and Autonomic Benefit at Higher Doses in Patients With Mild to Moderate Heart Failure and Normal Sinus Rhythm?

AbstractObjectives. This study sought to examine the hemodynamic and autonomic dose response to digoxin.Background. Previous studies have demonstrated an increase in contractility and heart rate variability with digitalis preparations. However, little is known about the dose-response to digoxin, which has a narrow therapeutic window.Methods. Nineteen patients with moderate heart failure and a left ventricular ejection fraction <0.45 were studied hemodynamically using echocardiography and blood pressure at baseline and after 2 weeks of low dose (0.125 mg daily) and 2 weeks of moderate dose digoxin (0.25 mg daily). Loading conditions were altered with nitroprusside at each study. Autonomic function was studied by assessing heart rate variability on 24-h Holter monitoring and plasma norepinephrine levels during supine rest.Results. Low dose digoxin provided a significant increase in ventricular performance, but no further increase was seen with the moderate dose. Low dose digoxin reduced heart rate and increased heart rate variability. Moderate dose digoxin produced no additional increase in heart rate variability or reduction in sympathetic activity, as manifested by heart rate, plasma norepinephrine or low frequency/high frequency power ratio. In addition, we did not find that either low or moderate dose digoxin increased parasympathetic activity.Conclusions. We conclude that moderate dose digoxin provides no additional hemodynamic or autonomic benefit for patients with mild to moderate heart failure over low dose digoxin. Because higher doses of digoxin may predispose to arrhythmogenesis, lower dose digoxin should be considered in patients with mild to moderate heart failure.(J Am Coll Cardiol 1997;29:1206–13

Effect of metoprolol on myocardial function and energetics in patients with nonischemic dilated cardiomyopathy: A randomized, double-blind, placebo-controlled study

AbstractObjectives. This study examined the of metoprolol on left ventricular performance, efficiency, neurohormonal activation and myocardial respiratory quotient in patients with dilated cardiomyopathy.Background.The mechanism by which beta-adrenergie blockade improves ejection fraction in patients with dilated cardiomyopathy remains an enigma. Thus, we undertook an extensive hemodynamic evaluation of this mechanism. In addition, because animal models have shown that catecholamine exposure may increase relative fatty acid utilization, we hypothesized that antagonism of sympathetic stimulation may result in increased carbohydrate utilization.Methods. This was a randomized, double-blind, prospective trial in which 24 men with nonischemic dilated cardiomyopathy underwent cardiac catheterization before and after 3 months of therapy with metoprolol (n = 15) or placebo (n = 9) in addition to standard therapy. Pressure-volume relations were examined using a micromanometer catheter and digital ventriculography.Results. At baseline, the placebo-treated patients had somewhat more advanced left ventricular dysfunction. Ejection fraction and left ventricular performance improved only in the metoprolol-treated patients. Stroke and minute work increased without an increase in myocardial oxgen consumption, suggesting increased myocardial efficiency. Further increases in ejection fraction were seen between 3 and 6 months in the metoprolol group. The placebo group had a significant increase in ejection fraction only after crossover to metoprolol. A significant relation the change in coronary sinus norepinephrine and myocardial respiratory quotient was seen, suggesting a possible effect of adrenergic deactivation on substrate utilization.Conclusions. These data demonstrate that in patients with cardiomyopthy, metoprolol treatment improves myocardial performance and energetics, and favorably alters substrate utilization. Beta-adrenergic blocking agents, such as metoprolol, are hemodynamically and energetically beneficial in the treatment of myocardial failure