Chronic Ischemic Left Ventricular Dysfunction Research Articles

Noninvasive evaluation of ischaemic heart disease: myocardial perfusion imaging or stress echocardiography?

Stress echocardiography and myocardial perfusion imaging are commonly used noninvasive imaging modalities for the evaluation of ischaemic heart disease. Both modalities have proved clinically useful in the entire spectrum of coronary artery disease. Both techniques can detect coronary artery disease and provide prognostic information. Both techniques can identify low-risk and high-risk subsets among patients with known or suspected coronary artery disease and thus guide patient management decisions. In patients with acute myocardial infarction, both techniques have been used to identify residual viable tissue and predict improvement of function over time. In patients with chronic ischaemic left ventricular (LV) dysfunction, viability assessment with either modality can be used to predict improvement of function after revascularisation and thus guide patient treatment.

Myocardial viability inchronic ischemic heart disease: Comparison of contrast-enhanced magnetic resonance imaging with 18F-fluorodeoxyglucose positron emission tomography

ObjectivesWe sought to compare contrast-enhanced magnetic resonance imaging (ceMRI) with nuclear metabolic imaging for the assessment of myocardial viability in patients with chronic ischemic heart disease and left ventricular (LV) dysfunction. BackgroundContrast-enhanced MRI has been shown to identify scar tissue in ischemically damaged myocardium. MethodsTwenty-six patients with chronic coronary artery disease and LV dysfunction (mean ejection fraction 31 ± 11%) underwent 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET), technetium-99m tetrofosmin single-photon emission computed tomography (SPECT), and ceMRI. In a 17-segment model, the segmental extent of hyperenhancement (SEH) by ceMRI, defined as the relative amount of contrast-enhanced tissue per myocardial segment, was compared with segmental FDG and tetrofosmin uptake by PET and SPECT. ResultsIn severely dysfunctional segments (n = 165), SEH was 9 ± 14%, 33 ± 25% (p < 0.05), and 80 ± 23% (p < 0.05) in segments with normal metabolism/perfusion, metabolism/perfusion mismatch, and matched defects, respectively. Segmental glucose uptake by PET was inversely correlated to SEH (r = −0.86, p < 0.001). By receiver operator characteristic curve analysis, the area under the curve was 0.95 for the differentiation between viable and non-viable segments. At a cutoff value of 37%, SEH optimally differentiated viable from non-viable segments defined by PET. Using this threshold, the sensitivity and specificity of ceMRI to detect non-viable myocardium as defined by PET were 96% and 84%, respectively. ConclusionsContrast-enhanced MRI allows assessment of myocardial viability with a high accuracy, compared with FDG-PET, in patients with chronic ischemic heart disease and LV dysfunction.

Functional effect of glucose, insulin and potassium in patients with chronic ischemic left ventricular dysfunction

Functional effect of glucose, insulin and potassium in patients with chronic ischemic left ventricular dysfunction

Future strategies of reverse remodeling prevention of hibernation

A complex interrelationship exists among chronic ischemic left ventricular dysfunction, persistence of myocardial viability and possibility to limit progression of chronic heart failure. Cardiac remodeling is influenced by several factors still under investigation. Hibernation is basically an adaptive mechanism to chronically abnormal coronary blood flow, characterized by metabolic and structural alterations of the cardiac tissue, that are fully recovered upon revascularization. The estimate of the prevalence of myocardial viability in patients with chronic ischemic left ventricular dysfunction is crucial and different figures can be obtained by applying different diagnostic techniques and analyzing different cohorts of patients. In patients with chronic heart failure and substantial areas of myocardial ischemia and viability, revascularization is likely to prolong survival. The amount of viable myocardium needed to be clinically relevant remains to be established: only randomized prospective studies, focusing on both functional improvement and prognosis, will give an evidence-based conclusion. An aggressive and thoughtful surgical approach to patients with ischemic heart failure can yield satisfying long-term results, with survival rates superior to medical management alone, and can constitute a true and valid alternative to heart transplantation.

Evaluation of myocardial viability with contrast echocardiography

Identification of viable myocardium after acute myocardial infarction (MI) or in the setting of severe chronic ischemic heart disease has important clinical implications. Myocardial contrast echocardiography (MCE) has been used for the evaluation of myocardial viability by assessing myocardial perfusion and microvascular integrity. In acute MI, MCE can identify the no-reflow phenomenon after revascularization, which has significant implications regarding recovery of function and clinical outcomes. Serial changes in myocardial perfusion can also be evaluated for the prediction of ultimate recovery of function. In the setting of chronic ischemic left ventricular dysfunction, early studies have shown that MCE is helpful in the identification of myocardial hibernation and in the prediction of recovery of function after revascularization, with accuracy similar to radionuclide techniques. Preliminary studies using the new quantitative MCE parameters of myocardial blood flow and velocity derived from intravenous contrast administration appear to enhance the diagnostic accuracy of MCE in the evaluation of myocardial viability.

Evaluation of patients with chronic ischaemic left ventricular dysfunction - assessment of tissue viability

There is growing interest in the assessment of myocardial viability in patients with ischaemic left ventricular dysfunction, in an attempt to identify those patients most likely to show functional improvement post-revascularization. Various techniques, focusing on dierent ‘viability characteristics’, are currently available. Of these, myocardial perfusion imaging (MPI) and dobutamine stress echocardiography are used most often; however, nuclear imaging techniques are more sensitive for the assessment of viable tissue. Revascularization of patients with viable tissue has been shown to improve function, reduce heart failure symptoms, improve exercise capacity and improve survival compared with patients with viable myocardium treated medically. Thus, assessment of viability using MPI may guide optimal management of patients with ischaemic left ventricular dysfunction.

The need for standardisation of cardiac FDG PET imaging in the evaluation of myocardial viability in patients with chronic ischaemic left ventricular dysfunction.

The evaluation of myocardial glucose utilisation with fluorine-18 fluorodeoxyglucose (FDG) and positron emission tomography is currently considered the most reliable tool for the identification of myocardial viability. However, the investigations using FDG imaging to predict improvement in left ventricular (LV) function after revascularisation have reported wide ranges for sensitivity (71%-100%) and, in particular, for specificity (33%-91%). The variable results may be related to differences in study populations but also to differences in the imaging protocols employed. Detailed analysis of the published studies has revealed differences in study populations, patient selection criteria, the methods for assessing changes in LV function post revascularisation and the timing of these assessments. Even more importantly, protocols have varied substantially with regard to imaging equipment, perfusion tracers, metabolic conditions, data analysis and interpretation of results. In addition, evaluation of patients with insulin resistance appears to represent a specific challenge. This review examines the different study protocols and methodologies used for myocardial FDG imaging in order to draw conclusions concerning optimal imaging protocols. It appears that the optimisation and standardisation of study protocols and analysis of FDG images for the assessment of myocardial viability are critical. In addition, multi-centre trials seem warranted on prediction of long-term function, congestive heart failure symptoms, survival and quality of life.

Predicting revascularization outcome in patients with coronary artery disease and left ventricular dysfunction (data from the SEMINATOR study)

A main goal of revascularization in patients with chronic ischemic cardiomyopathy is to improve global left ventricular (LV) function. This study aimed to verify whether it is possible to predict an increase in LV ejection fraction (EF) after revascularization on the basis of the extent of LV asynergy, myocardial viability, and revascularization completeness. We studied 77 patients with chronic LV ischemic dysfunction using baseline resting and nitrate-enhanced technetium-99m sestamibi single-photon emission computed tomography. Regional wall motion and global LVEF were assessed with echocardiography before and after revascularization, which was complete in 51 patients and incomplete in 26. The number of viable asynergic segments included in revascularized coronary artery territories was the strongest predictor of significant (≥5 EF U) functional improvement in univariate discriminant analysis. According to multivariate stepwise discriminant analysis, this parameter, together with the number of baseline asynergic segments, allowed the detection of patients with significant LVEF improvement with 75% accuracy. With use of a multivariate regression model, including the 2 mentioned variables, the measure of postrevascularization LVEF increase could be accurately quantified (R 2 0.43, p <0.000001). In conclusion, this study suggests that the severity of baseline asynergy, the extent of myocardial viability, and the completeness of revascularization are the main determinants of postrevascularization functional recovery in patients with LV ischemic dysfunction, and that on the basis of these variables it is possible to predict the measure of LVEF increase.

Use of cyclic variation of integrated backscatter to assess contractile reserve and myocardial viability in chronic ischemic left ventricular dysfunction.

The detection of viable myocardium has important implications for management, but use of stress echocardiography to detect this is subjective and requires exposure to dobutamine. We investigated whether cyclic variation (CV) of integrated backscatter (IB) from the apical views could provide a resting study for detection of contractile reserve (CR) and prediction of myocardial viability in 27 patients with chronic ischemic left ventricular (LV) dysfunction. Repeat echocardiography was performed after 6.7 +/- 3.8 months of follow-up; 14 patients underwent revascularization and 13 were treated medically. Using a standardized dobutamine echocardiography (DbE) protocol, images from three apical views were acquired at 80-120 frames/sec at rest and during stress. CR was identified if improvement of wall motion was observed at low dose (5 or 10 microg/kg/min) DbE. Myocardial viability was characterized by improvement at follow-up echocardiography in patients with revascularization. CVIB at rest and low dose dobutamine were assessed in 194 segments with resting asynergy (severe hypokinesis or akinesis), of which 88 (45%) were in patients who underwent revascularization. Of these, CVIB could be measured in 190 (98%) segments at rest and 185 (95%) at low dose dobutamine. Sixty-two (33%) segments had CR during low dose DbE and 50 (57%) segments showed wall-motion recovery (myocardial viability) at follow-up echocardiography. Segments with CR had significantly higher CVIB at rest (P < 0.001) and low dose dobutamine (P = 0.005) than segments without CR. Using optimal thresholds of CVIB (> 8.2 dB) at rest, the accuracy of CVIB for detecting CR was 70%. Compared with nonviable segments, viable segments had significantly higher CVIB at rest (P < 0.001) and low dose dobutamine (P < 0.001). Using optimal thresholds of CVIB (> 5.3 dB) at rest, the accuracy of CVIB for detecting myocardial viability was 85%, which was higher than that in conventional DbE (62%, P < 0.01). Thus, assessment of CVIB from the apical views is a feasible and accurate tool for detecting CR and predicting myocardial viability in chronic LV dysfunction.

Functional effect of glucose, insulin, and potassium in patients with chronic ischemic left ventricular dysfunction

Functional effect of glucose, insulin, and potassium in patients with chronic ischemic left ventricular dysfunction

Effect of revascularization on left ventricular remodeling in patients with heart failure from severe chronic ischemic left ventricular dysfunction

Few data exist regarding the effect of revascularization on left ventricular (LV) geometry in patients with severe LV systolic dysfunction and viable myocardium. We hypothesized that patients with chronic ischemic LV dysfunction but viable myocardium will have improved LV geometry after revascularization, which in turn will improve long-term outcome. Accordingly, 70 patients with severe ischemic LV dysfunction (LV ejection fraction <0.35) were studied at rest. They then either underwent revascularization (n = 36) or were treated medically (n = 34). Fifty-four patients had viable myocardium, and 16 did not. They were evaluated for change in LV function and geometry (size and shape) a mean of 21 months later. Further follow-up was performed for a mean of 3.5 years to determine outcome. Patients with viable myocardium had improvement not only in regional and global function, but also in LV geometry (shape and size), which was independent of and incremental to the improvement in function. On long-term follow-up, change in LV end-systolic volume was the only multivariate discriminator between 15 patients who died and 55 who did not, irrespective of whether they had undergone revascularization. Thus, measurement of the effect of revascularization of viable myocardium in chronic ischemic heart disease should not only include improvement in resting regional and global LV function, but also LV geometry. Improvement in LV geometry contributes to better LV systolic function, which in turn is the best predictor of survival after revascularization.

Plasma N-terminal pro-brain natriuretic peptide and adrenomedullin: Prognostic utility and prediction of benefit from carvedilol in chronic ischemic left ventricular dysfunction

OBJECTIVESWe sought to assess plasma concentrations of the amino (N)-terminal portion of pro-brain natriuretic peptide (N-BNP) and adrenomedullin for prediction of adverse outcomes and responses to treatment in 297 patients with ischemic left ventricular (LV) dysfunction who were randomly assigned to receive carvedilol or placebo.BACKGROUNDAlthough neurohormonal status has known prognostic significance in heart failure, the predictive power of either N-BNP or adrenomedullin in chronic ischemic LV dysfunction has not been previously reported.METHODSPlasma N-BNP and adrenomedullin were measured in 297 patients with chronic ischemic (LV) dysfunction before randomization to carvedilol or placebo, added to established treatment with a converting enzyme inhibitor and loop diuretic (with or without digoxin). The patients’ clinical outcomes, including mortality and heart failure events, were recorded for 18 months.RESULTSAbove-median N-BNP and adrenomedullin levels conferred increased risks (all p < 0.001) of mortality (risk ratios [95% confidence intervals]: 4.67 [2–10.9] and 3.92 [1.76–8.7], respectively) and hospital admission with heart failure (4.7 [2.2–10.3] and 2.4 [1.3–4.5], respectively). Both of these predicted death or heart failure independent of age, New York Heart Association functional class, LV ejection fraction, previous myocardial infarction or previous admission with heart failure. Carvedilol reduced the risk of death or heart failure in patients with above-median levels of N-BNP or adrenomedullin, or both, to rates not significantly different from those observed in patients with levels below the median value.CONCLUSIONSIn patients with established ischemic LV dysfunction, plasma N-BNP and adrenomedullin are independent predictors of mortality and heart failure. Carvedilol reduced mortality and heart failure in patients with higher pre-treatment plasma N-BNP and adrenomedullin.

Plasma N-terminal pro-brain natriuretic peptide and adrenomedullin: Prognostic utility and prediction of benefit from carvedilol in chronic ischemic left ventricular dysfunction A. Mark Richards, Robert Doughty, M. Gary Nicholls, Stephen MacMahon, Norman Sharpe, Judy Murphy, Eric A. Espiner, Christopher Frampton, Tim G. Yandle. Christchurch School of Medicine, Christchurch, New Zealand, University of Auckland, Auckland, New Zealand

Plasma N-terminal pro-brain natriuretic peptide and adrenomedullin: Prognostic utility and prediction of benefit from carvedilol in chronic ischemic left ventricular dysfunction A. Mark Richards, Robert Doughty, M. Gary Nicholls, Stephen MacMahon, Norman Sharpe, Judy Murphy, Eric A. Espiner, Christopher Frampton, Tim G. Yandle. Christchurch School of Medicine, Christchurch, New Zealand, University of Auckland, Auckland, New Zealand

Effect of revascularization on left ventricular remodelling in patients with severe chronic ischaemic left ventricular dysfunction: Influence on mortality Roxy Senior, Avijit Lahiri, Sanjiv Kaul. Northwick Park Hospital, Harrow, United Kingdom

Effect of revascularization on left ventricular remodelling in patients with severe chronic ischaemic left ventricular dysfunction: Influence on mortality Roxy Senior, Avijit Lahiri, Sanjiv Kaul. Northwick Park Hospital, Harrow, United Kingdom

Increased right ventricular thallium uptake in chronic ischemic left ventricular dysfunction: Evidence for improvement after coronary artery revascularization Maung M. Khin, Anastasia N. Kitsiou, Joann Carson, Stephen L. Bacharach, Vasken Dilsizian. National Institutes of Health, Bethesda, MD

Increased right ventricular thallium uptake in chronic ischemic left ventricular dysfunction: Evidence for improvement after coronary artery revascularization Maung M. Khin, Anastasia N. Kitsiou, Joann Carson, Stephen L. Bacharach, Vasken Dilsizian. National Institutes of Health, Bethesda, MD

Mechanism of ischemic mitral regurgitation with segmental left ventricular dysfunction: three-dimensional echocardiographic studies in models of acute and chronic progressive regurgitation

OBJECTIVESThis study aimed to separate proposed mechanisms for segmental ischemic mitral regurgitation (MR), including left ventricular (LV) dysfunction versus geometric distortion by LV dilation, using models of acute and chronic segmental ischemic LV dysfunction evaluated by three-dimensional (3D) echocardiography.BACKGROUNDDysfunction and dilation—both mechanisms with practical therapeutic implications—are difficult to separate in patients.METHODSIn seven dogs with acute left circumflex (LCX) coronary ligation, LV expansion was initially restricted and then permitted to occur. In seven sheep with LCX branch ligation, LV expansion was also initially limited but became prominent with remodeling over eight weeks. Three-dimensional echo reconstruction quantified mitral apparatus geometry and MR volume.RESULTSIn the acute model, despite LV dysfunction with ejection fraction = 23 ± 8%, MR was initially trace with limited LV dilation, but it became moderate with subsequent prominent dilation. In the chronic model, MR was also initially trace, but it became moderate over eight weeks as the LV dilated and changed shape. In both models, the only independent predictor of MR volume was increased tethering distance from the papillary muscles (PMs) to the anterior annulus, especially medial and posterior shift of the ischemic medial PM, measured by 3D reconstruction (r2= 0.75 and 0.86, respectively). Mitral regurgitation volume did not correlate with LV ejection fraction or dP/dt.CONCLUSIONSSegmental ischemic LV contractile dysfunction without dilation, even in the PM territory, fails to produce important MR. The development of MR relates strongly to changes in the 3D geometry of the mitral apparatus, with implications for approaches to restore a more favorable configuration.

Resting ultrasonic tissue characterization and dobutamine stress echocardiography for prediction of functional recovery in chronic left ventricular ischemic dysfunction.

This study was designed to assess the diagnostic accuracy of the percentage of resting systolic wall thickening (WT), dobutamine stress echocardiography (DSE), resting cyclic variation of integrated backscatter (IBS-CV), and low-dose dobutamine stress IBS-CV (DSE-IB) for the prediction of regional function recovery (RFR) in patients with chronic left ventricular (LV) ischemic dysfunction. The study also evaluated whether or not global LV function affected the diagnostic accuracy. All studies were conducted before percutaneous transluminal coronary angioplasty (PTCA) and RFR was assessed after PTCA (mean interval, 10 months) in 30 patients with chronic LV ischemic dysfunction. Patients were divided into 2 groups according to the LV ejection fraction (LVEF): group A, LVEF<40%, n=14; group B, LVEF> or =40%, n=16. Of a total of 480 segments, 37 initially demonstrating akinetic wall motion before PTCA were analyzed. The wall motion of 24 of the 37 segments improved on visual analysis after PTCA. In the prediction of RFR, resting WT, DSE, resting IBS-CV and DSE-IB had sensitivities of 79%, 79%, 92% and 62%, and specificities of 54%, 84%, 83% and 69%, respectively. In particular, the resting IBS-CV in group A, as well as DSE, was an excellent predictor of RFR (sensitivity, 100%; specificity, 86%; vs sensitivity, 82%; specificity, 78%; respectively). Therefore, both resting IBS-CV and DSE are useful predictors for RFR in patients with chronic LV ischemic dysfunction.

7.1 Prevalence of myocardial viability assessed by single-photon emission computed tomography in patients with chronic ischemic left ventricular dysfunction

7.1 Prevalence of myocardial viability assessed by single-photon emission computed tomography in patients with chronic ischemic left ventricular dysfunction

Sestamibi SPECT in the detection of myocardial viability in patients with chronic ischemic left ventricular dysfunction: Comparison between visual and quantitative analysis

Background. Technetium 99m sestamibi cardiac scintigraphy is widely used as a means of predicting myocardial viability in patients with chronic ischemic left ventricular (LV) dysfunction. No data are available comparing the results of visual and quantitative analysis of tomographic imaging in the assessment of myocardial viability. The aim of this study was to directly compare visual and quantitative analysis of resting sestamibi single photon emission computed tomography in the identification of viable myocardium in patients with chronic LV dysfunction. Methods and Results. Sixty-five patients with an earlier myocardial infarction and LV dysfunction that had occurred within 1 week underwent echocardiography and resting sestamibi SPECT. In each patient, regional tracer distribution was visually assessed and quantitatively measured in 13 segments. Regional LV function was evaluated in corresponding segments by means of echocardiography. All patients underwent revascularization, and echocardiography was repeated 12 months later as a means of assessing the recovery of regional LV function. Among all akinetic or dyskinetic revascularized segments, 66 of 112 viable segments (59%) and 85 of 100 nonviable segments (81%) were identified by means of visual analysis. Eighty-two of 112 viable segments (73%; P < .05 vs visual analysis) and 74 of 100 nonviable segments (74%; P = .3 vs visual analysis) were identified by means of quantitative analysis, with a threshold of 55%. Receiver operating characteristic curve areas constructed by using visual and quantitative analyses for the detection of myocardial viability in all 212 akinetic or dyskinetic segments were 0.79 ± 0.04 and 0.81 ± 0.03, respectively ( P = not significant). Overall concordance in the detection of myocardial viability between visual and quantitative analysis was observed in 165 of akinetic or dyskinetic dysfunctional segments (78%), with a κ value of 0.6. Conclusions. The results of this study demonstrate that, in patients with chronic myocardial infarction and LV dysfunction, visual and quantitative analysis of sestamibi tomographic images at rest have similar overall accuracy in predicting the recovery of LV function after coronary revascularization procedures. (J Nucl Cardiol 2000;7:406-13.)

Comparison of simultaneous dobutamine echocardiography and thallium-201 stress-reinjection single-photon emission computed tomography in predicting improvement of chronic myocardial dysfunction after revascularization

Previous studies have shown that ultrasonic integrated backscatter is valuable in characterizing stunned myocardium. Recent investigations have demonstrated that resting cardiac cycle-dependent variation of integrated backscatter closely paralleled the contractile reserve in patients with chronic left ventricular ischemic dysfunction. The purpose of this study was to validate whether ultrasonic tissue characterization (UTC) compared with dobutamine stress echocardiography (DSE) and thallium-201 stress-reinjection single-photon emission computed tomography (Tl-SPECT) could predict reversible myocardial dyssynergy in patients with chronic coronary artery disease. Forty-eight patients with stable coronary artery disease underwent UTC, DSE, and Tl-SPECT simultaneously before successful coronary revascularization and were followed up with echocardiograms at rest >3 months later. Among the 58 investigated segments, the weighted amplitude, a composite parameter derived from the integrated backscatter power curve, was larger for those groups with greater functional recovery (p <0.001). For the persistent akinetic segments, the weighted amplitudes were small with large deviations of the nadir ratios that represented the asynchrony between the intramural contractile events and the global systole. Using the cut-off value 2.0 of the weighted amplitude, the sensitivity and specificity for predicting functional improvement after revascularization were both 82.8% (κ = 0.66) and comparable to the sensitivity and specificity of DSE and Tl-SPECT. UTC, delineating the myocardial physical state and intramural contraction, can be a novel approach in predicting functional improvement of chronic dyssynergy after revascularization.