Left ventricular end-systolic volume index in patients with ischemic cardiomyopathy predicts postoperative ventricular function

Effects of different surgical strategies and left ventricular remodelling on the outcomes of coronary artery bypass grafting in heart failure patients with reduced ejection fraction

Background

Ischaemic heart failure with reduced ejection fraction (HFrEF) caused by coronary artery disease accounts for the largest proportion of heart failure cases with the worst prognosis. Coronary artery bypass grafting (CABG) is the most effective treatment for ischaemic HFrEF. On-pump and off-pump are the two surgical methods used for CABG. Whether patients with HFrEF should undergo on- or off-pump CABG is controversial in coronary heart disease surgery. The left ventricular end-systolic volume index (LVSEVI) is the gold standard for evaluating the severity of left ventricular remodelling; however, its effect on the perioperative risk and long-term survival rate of patients with HFrEF undergoing CABG remains unclear.

Methods

This single centre prospective cohort analysis included 118 coronary heart disease patients with symptoms and signs of heart failure and a left ventricular ejection fraction (LVEF) of <40% who were enrolled consecutively from January 2019 to December 2023. Operative mortality, perioperative complications, and long-term survival were compared among patients treated with various LVESVIs and surgical methods. The primary outcomes were cardiac death, myocardial infarction, heart failure, stroke, and revascularization, (percutaneous coronary intervention or redo CABG) with a median follow-up of 38 ± 10 months.

Results

The 30-day postoperative mortality of 118 patients was 6.8%. Patients in the off-pump group had significantly higher perioperative mortality than those in the on-pump group (12.5% vs. 3.8%, p = 0.03). In the off-pump group, a higher proportion of patients required perioperative mechanical assistance, such as intra-aortic artery balloon pump (IABP) or extracorporeal membrane oxygenation (ECMO), compared to those in the on-pump group (IABP: 75% vs. 47.4%, p = 0.004; ECMO: 22.5% vs. 1.3%, p = 0.000). Patients in the off-pump group were more likely to have postoperative atrial fibrillation (AF) (35% vs. 14.1%, p = 0.01). In the on-pump group, the incidence of postoperative AF (25% vs. 6.5%, p = 0.02) and IABP use (62.5% vs. 36.9%, p = 0.03) were significantly higher in patients with more severe left ventricular remodelling than in those with less severe left ventricular remodelling. In the off-pump group, patients with more severe left ventricular remodelling had higher ECMO usage (38.9% vs. 9.1%, p = 0.04), incidence of postoperative AF (61.1% vs. 13.6%, p = 0.02), and perioperative mortality (22.2%). Major adverse cardiac event (MACE)-free survival rate was significantly higher in the on-pump group than in the off-pump group, and there was no significant difference in MACE free survival rates between the two groups of patients with different degrees of left ventricular remodelling.

Conclusion

On-pump bypass is a better surgical procedure for patients with ischaemic HFrEF, especially those with severe left ventricular remodelling. Left ventricular remodelling increases perioperative mortality but has no effect on long-term survival.

Controversy: Critical Review of the Stich Trial and Assessment of Viability. “Back to the Future” Or Maybe Not

The management of patients with coronary artery disease and heart failure has been debated for years. In the 1980’s Braunwald coined the words “viability” and “stunning”. Multiple trials have been done since then. Since the early eighties coronary bypass grafting was considered as gold standard for patients with impaired left ventricular fraction and coronary artery disease. Since then, nuclear imaging studies have been used to evaluate the “viability” of the impaired areas and to decide if revascularisation would be reasonable. Beginning with the CASS study and ending with the more recent STICH study we aim to provide a “bird’s eye view” of the pros and cons for revascularisation. In addition, we aim to shed some light on the daily advancements in medical management, including devices and not just medication. We therefore chose the title “Back to the future” or maybe not.

Effects of myocardial viability and left ventricular remodeling on survival of patients with heart failure and reduced ejection fraction after coronary artery bypass grafting

Background

Heart failure with reduced ejection fraction (HFrEF) caused by coronary heart disease (CHD) accounts for the largest proportion of patients with heart failure and is associated with the poorest prognosis. However, date on the perioperative risk and long-term survival of patients with HFrEF are limited. The present study aimed at exploring the effects of the left ventricular end-systolic volume index (LVESVI) and myocardial viability on perioperative risk and long-term survival after coronary artery bypass grafting (CABG) in patients with HFrEF.

Methods

This is a single center, prospective, observational study. CHD patients with symptoms and signs of heart failure and a left ventricular ejection fraction (LVEF) <40% were enrolled consecutively from January 2014 to February 2018. Operative mortality, perioperative complications and long-term survival were compared in the patients with various LVESVIs and myocardial viabilities. The primary outcomes were cardiac death, myocardial infarction, heart failure, stroke and revascularization [percutaneous coronary intervention (PCI) or redo CABG] with a median follow-up of 30±12 months.

Results

Perioperative mortality was 6.8% in the 118 patients in this study. Perioperative mortality was significantly higher in the low myocardial viability (LMV) group than in the high myocardial viability (HMV) group (12.5% vs. 3.8%, P=0.034). The 12-, 24-, 36-month major adverse cardiac event (MACE)-free survival rate of patients with HMV was significantly higher than that of patients with LMV (HMV vs. LMV: 96.9% vs. 88.6%, 93.4% vs. 85.5%, 79.4% vs. 68.2%, P=0.004). There was no difference in MACE-free survival among patients with different degrees of left ventricular remodeling within each group.

Conclusions

Myocardial viability is an important factor that affects the perioperative mortality and long-term survival of patients with ischemic HFrEF after CABG. Left ventricular remodeling increases perioperative mortality but has no effect on long-term survival.

Contrasting Effects of Pharmacological, Procedural, and Surgical Interventions on Proportionate and Disproportionate Functional Mitral Regurgitation in Chronic Heart Failure

Two distinct pathways can lead to functional mitral regurgitation (MR) in patients with chronic heart failure and a reduced ejection fraction. When remodeling and enlargement of the left ventricle (LV) cause annular dilatation and tethering of the mitral valve leaflets, there is a linear relationship between LV end-diastolic volume and the effective regurgitant orifice area of the mitral valve. These patients, designated as having proportionate MR, respond favorably to treatments that lead to reversal of LV remodeling and a decrease in LV volumes (eg, neurohormonal antagonists and LV assist devices), but they may not benefit from interventions that are directed only at the mitral valve leaflets (eg, transcatheter mitral valve repair). In contrast, when ventricular dyssynchrony causes functional MR attributable to unequal contraction of the papillary muscles, the magnitude of regurgitation is greater than that predicted by LV volumes. These patients, designated as having severe but disproportionate MR, respond favorably to treatments that are directed to the mitral valve leaflets or their supporting structures (eg, cardiac resynchronization or transcatheter mitral valve repair), but they may derive little benefit from interventions that act only to reduce LV cavity size (eg, pharmacological treatments). This novel conceptual framework reflects the important interplay between LV geometry and mitral valve function in determining the clinical presentation of patients, and it allows characterization of the determinants of functional MR to guide the most appropriate therapy in the clinical setting.

Severity of Remodeling, Myocardial Viability, and Survival in Ischemic LV Dysfunction After Surgical Revascularization

OBJECTIVES

This study sought to test the hypothesis that end-systolic volume (ESV), as a marker of severity of left ventricular (LV) remodeling, influences the relationship between myocardial viability and survival in patients with coronary artery disease and LV systolic dysfunction.

BACKGROUND

Retrospective studies of ischemic LV dysfunction suggest that the severity of LV remodeling determines whether myocardial viability predicts improved survival with surgical compared with medical therapy, with coronary artery bypass grafting (CABG) only benefitting patients with viable myocardium who have smaller ESV. However, this has not been tested prospectively.

METHODS

Interactions of end-systolic volume index (ESVI), myocardial viability, and treatment with respect to survival were assessed in patients in the prospective randomized STICH (Comparison of Surgical and Medical Treatment for Congestive Heart Failure and Coronary Artery Disease) trial of CABG versus medical therapy who underwent viability assessment (n = 601; age 61 ± 9 years; ejection fraction ≤35%), with a median follow-up of 5.1 years. Median ESVI was 84 ml/m(2). Viability was assessed by single-photon emission computed tomography or dobutamine echocardiography using pre-specified criteria.

RESULTS

Mortality was highest among patients with larger ESVI and nonviability (p < 0.001), but no interaction was observed between ESVI, viability status, and treatment assignment (p = 0.491). Specifically, the effect of CABG versus medical therapy in patients with viable myocardium and ESVI ≤84 ml/m(2) (hazard ratio [HR]: 0.85; 95% confidence interval [CI]: 0.56 to 1.29) was no different than in patients with viability and ESVI >84 ml/m(2) (HR: 0.87; 95% CI: 0.57 to 1.31). Other ESVI thresholds yielded similar results, including ESVI ≤60 ml/m(2) (HR: 0.87; 95% CI: 0.44 to 1.74). ESVI and viability assessed as continuous rather than dichotomous variables yielded similar results (p = 0.562).

CONCLUSIONS

Among patients with ischemic cardiomyopathy, those with greater LV ESVI and no substantial viability had worse prognosis. However, the effect of CABG relative to medical therapy was not differentially influenced by the combination of these 2 factors. Lower ESVI did not identify patients in whom myocardial viability predicted better outcome with CABG relative to medical therapy. (Comparison of Surgical and Medical Treatment for Congestive Heart Failure and Coronary Artery Disease [STICH]; NCT00023595).

Prediction of Long-Term Survival in Patients with End-Stage Heart Failure Secondary to Ischemic Heart Disease: Surgical Correction and Volumetric Analysis

PURPOSE

Ischemic heart disease (IHD) may result in lethal conditions such as ischemic cardiomyopathy (ICM) and mitral regurgitation (MR).

METHODS

We hypothesized preoperative LV volume would be highly associated with long-term survival in such patients. We retrospectively evaluated effects of LV end-systolic volume index (LVESVI) on survival.

RESULTS

Patients were divided into two groups according to LVESVI; Group S (n = 19, <100 ml/m(2)), and L (n = 55, >100 ml/m(2)). There were 74 patients (male 61, female 13; 61 ± 10 y.o.). There was no statistical significance in preoperative parameters, including ejection fraction (EF), severity of MR, severity of tricuspid regurgitation (TR), and right ventricular systolic pressure (RVSP). After operation, LVESVI and severity of MR were statistically reduced in both groups. However, EF, severity of TR and RVSP were not statistically alleviated in both groups. In Group S, 5- and 10-year survival rates were 93% and 48%. In Group L, 5- and 10-year survival rates were 50% and 29%. There was a statistical difference in long-term survival between two groups.

CONCLUSIONS

Preoperative LV volume would be one of the risk factors for long-term survival in patients with congestive heart failure secondary to IHD. Careful follow-up and optimal treatment should be recommended before LV dimension becomes too large.

Characterizing heart failure in the ventricular volume domain

Heart failure (HF) may be accompanied by considerable alterations of left ventricular (LV) volume, depending on the particular phenotype. Two major types of HF have been identified, although heterogeneity within each category may be considerable. All variants of HF show substantially elevated LV filling pressures, which tend to induce changes in LV size and shape. Yet, one type of HF is characterized by near-normal values for LV end-diastolic volume (EDV) and even a smaller end-systolic volume (ESV) than in matched groups of persons without cardiac disease. Furthermore, accumulating evidence indicates that, both in terms of shape and size, in men and women, the heart reacts differently to adaptive stimuli as well as to certain pharmacological interventions. Adjustments of ESV and EDV such as in HF patients are associated with (reverse) remodeling mechanisms. Therefore, it is logical to analyze HF subtypes in a graphical representation that relates ESV to EDV. Following this route, one may expect that the two major phenotypes of HF are identified as distinct entities localized in different areas of the LV volume domain. The precise coordinates of this position imply unique characteristics in terms of the actual operating point for LV volume regulation. Evidently, ejection fraction (EF; equal to 1 minus the ratio of ESV and EDV) carries little information within the LV volume representation. Thus far, classification of HF is based on information regarding EF combined with EDV. Our analysis shows that ESV in the two HF groups follows different patterns in dependency of EDV. This observation suggests that a superior HF classification system should primarily be founded on information embodied by ESV.

Carotid body denervation improves autonomic and cardiac function and attenuates disordered breathing in congestive heart failure

In congestive heart failure (CHF), carotid body (CB) chemoreceptor activity is enhanced and is associated with oscillatory (Cheyne-Stokes) breathing patterns, increased sympathetic nerve activity (SNA) and increased arrhythmia incidence. We hypothesized that denervation of the CB (CBD) chemoreceptors would reduce SNA, reduce apnoea and arrhythmia incidence and improve ventricular function in pacing-induced CHF rabbits. Resting breathing, renal SNA (RSNA) and arrhythmia incidence were measured in three groups of animals: (1) sham CHF/sham-CBD (sham-sham); (2) CHF/sham-CBD (CHF-sham); and (3) CHF/CBD (CHF-CBD). Chemoreflex sensitivity was measured as the RSNA and minute ventilatory (VE) responses to hypoxia and hypercapnia. Respiratory pattern was measured by plethysmography and quantified by an apnoea-hypopnoea index, respiratory rate variability index and the coefficient of variation of tidal volume. Sympatho-respiratory coupling (SRC) was assessed using power spectral analysis and the magnitude of the peak coherence function between tidal volume and RSNA frequency spectra. Arrhythmia incidence and low frequency/high frequency ratio of heart rate variability were assessed using ECG and blood pressure waveforms, respectively. RSNA and VE responses to hypoxia were augmented in CHF-sham and abolished in CHF-CBD animals. Resting RSNA was greater in CHF-sham compared to sham-sham animals (43 ± 5% max vs. 23 ± 2% max, P < 0.05), and this increase was not found in CHF-CBD animals (25 ± 1% max, P < 0.05 vs. CHF-sham). Low frequency/high frequency heart rate variability ratio was similarly increased in CHF and reduced by CBD (P < 0.05). Respiratory rate variability index, coefficient of variation of tidal volume and apnoea-hypopnoea index were increased in CHF-sham animals and reduced in CHF-CBD animals (P < 0.05). SRC (peak coherence) was increased in CHF-sham animals (sham-sham 0.49 ± 0.05; CHF-sham 0.79 ± 0.06), and was attenuated in CHF-CBD animals (0.59 ± 0.05) (P < 0.05 for all comparisons). Arrhythmia incidence was increased in CHF-sham and reduced in CHF-CBD animals (213 ± 58 events h(-1) CHF, 108 ± 48 events h(-1) CHF-CBD, P < 0.05). Furthermore, ventricular systolic (3.8 ± 0.7 vs. 6.3 ± 0.5 ml, P < 0.05) and diastolic (6.3 ± 1.0 vs. 9.1 ± 0.5 ml, P < 0.05) volumes were reduced, and ejection fraction preserved (41 ± 5% vs. 54 ± 2% reduction from pre-pace, P < 0.05) in CHF-CBD compared to CHF-sham rabbits. Similar patterns of changes were observed longitudinally within the CHF-CBD group before and after CBD. In conclusion, CBD is effective in reducing RSNA, SRC and arrhythmia incidence, while improving breathing stability and cardiac function in pacing-induced CHF rabbits.

Anterior wall viability and low ejection fraction predict functional improvement after CABG

BACKGROUND

Absence of myocardial hyperenhancement on cardiac magnetic resonance imaging (CMR) predicts functional improvement after coronary artery bypass graft surgery (CABG). However, not all patients with absence of hyperenhancement improve their left ventricular ejection fraction (LVEF) after CABG. We sought to identify other characteristics associated with improvement in LVEF after CABG.

METHODS

Preoperative CMR was obtained in 95 patients who underwent CABG from 2003 to 2007 at The Ohio State University Medical Center. Follow-up LVEF was assessed by echocardiogram between 3 wk and 2 y postoperatively (mean: 7±0.5 mo). Improvement in LVEF was defined as a postoperative increase in LVEF≥10%. CMR and clinical factors were analyzed for predictors of functional improvement.

RESULTS

Mean age was 61±1 y with 79 males. LVEF improved from 28%±2% preoperatively, to 38%±2% postoperatively (P<0.0001). Forty-three patients improved their LVEF. Patients who improved their LVEF had a lower preoperative LVEF (P=0.0001) and higher anterior wall viability (P=0.03). Preoperative LVEF (odds ratio 0.89, 95% CI 0.83-0.95, P=0.001) and left ventricular end systolic volume index (odds ratio 0.97, 95% CI 0.95-0.99, P=0.015) were predictors of improvement in LVEF by multivariable logistic regression analysis.

CONCLUSIONS

Recruitment of viable non functioning myocardium of the anterior wall is responsible for the improvement in ejection fraction. Low LVEF, non-remodeled left ventricle, and anterior wall viability predict improvement in ejection fraction after CABG. These criteria may help clinicians select patients who would benefit from surgical revascularization.

Ischemic cardiomyopathy: a clinical nuclear cardiology perspective

Ischemic cardiomyopathy results from severe extensive coronary artery disease, which is associated with left ventricular dysfunction and also, in many cases, with significant left ventricular dilatation. Mortality is high, especially in patients who satisfy myocardial viability criteria but who have not undergone revascularization. Although age, exercise capacity and comorbidity influence survival, the most important prognostic factors are the extent of the ischemia, myocardial viability and left ventricular remodeling, all of which can be successfully evaluated by gated myocardial perfusion single-photon emission computed tomography (SPECT).

Increase in end-systolic volume after exercise independently predicts mortality in patients with coronary heart disease: data from the Heart and Soul Study

AIMS

The predictive value of changes in global left ventricular (LV) size after exercise has not been studied. Left ventricular end-systolic volume (ESV) is a relatively load-independent echocardiographic marker of contractility that is easily measured. We investigated the role of the change in ESV at rest and after peak exercise on mortality among patients with stable coronary heart disease (CHD).

METHODS AND RESULTS

We performed exercise treadmill testing with stress echocardiography in 934 ambulatory subjects with CHD. End-systolic volume was measured immediately before and after exercise using 2D echocardiography. We defined ESV reversal as an increase in ESV after exercise, and we examined the association of ESV reversal with all-cause mortality during a median follow-up of 3.92 years. Of the 934 participants, 199 (21%) had ESV reversal. At the end of follow-up, mortality was higher among participants with ESV reversal than those without (26 vs. 11%; P < 0.001). After adjustment for clinical covariates, ESV reversal remained predictive of all-cause mortality (HR 2.0; 95% CI 1.4-2.9; P = 0.001). The association of ESV reversal with mortality also persisted after adjustment for exercise-induced wall-motion abnormalities (HR 1.7; 95% CI 1.1-2.3, P = 0.006). To determine if the effect of ESV reversal was independent from other echocardiographic measurements, we created a separate model adjusting for resting LV ejection fraction, ESV, end-diastolic volume, and LV mass. End-systolic volume reversal was the only significant predictor of mortality in this model (HR 2.1, 95% CI 1.4-3.0, P < 0.001).

CONCLUSION

End-systolic volume reversal is a novel parameter that independently predicts mortality in patients with CHD undergoing exercise treadmill echocardiography, even after adjustment for a wide range of clinical, echocardiographic, and treadmill exercise variables. Because measurement of ESV is simple, reproducible, and requires no additional imaging views, identification of ESV reversal during exercise echocardiography can provide useful complementary information for risk stratification.

Surgical treatment for heart failure: left ventricular restoration for cardiomyopathy

Congestive heart failure has become a major problem and the only surgical treatment for end-stage heart failure caused by dilated cardiomyopathy (DCM) had been heart transplantation. However, because of the shortage of donors, several procedures for non-transplant surgery have been developed. Published literature on left ventricular (LV) restoration was searched to review the new surgical procedures for treating patients with ischemic or non-ischemic DCM. LV restoration was initiated in the 1980s for repairing LV aneurysm. In the 1990s several surgical procedures were introduced for treating DCM, and the new evolving surgical treatment plays an important role in the management of DCM in the 21st century.

Prognostic value of left ventricular end-systolic volume index as a predictor of heart failure hospitalization in stable coronary artery disease: data from the Heart and Soul Study

OBJECTIVE

Left ventricular (LV) end-systolic volume indexed to body surface area (ESVI) is a simple yet powerful echocardiographic marker of LV remodeling that can be measured easily. The prognostic value of ESVI and its merit relative to other markers of LV remodeling in patients with coronary heart disease are unknown.

METHODS

We examined the association of ESVI with hospitalization for heart failure (HF) and mortality in a prospective study of patients with coronary heart disease.

RESULTS

Of the 989 participants, 110 (11%) were hospitalized for HF during 3.6 +/- 1.1 years of follow-up. Among participants in the highest ESVI quartile (> 25 mL/m(2)), 67 of 248 (27%) developed HF compared with 8 of 248 (3%) among those in the lowest quartile. The association between ESVI and HF hospitalization persisted after adjustment for potential confounders (hazard ratio 5.0, 95% confidence interval, 1.5-16.9; P = .01).

CONCLUSION

ESVI > 25 mL/m(2) is an independent predictor of hospitalization for HF in patients with stable coronary heart disease.

Long-term results of coronary artery bypass grafting in patients with left ventricular dysfunction

BACKGROUND

In this prospective study, we investigated the determinants of long-term outcome, symptoms, and left ventricular function after coronary artery bypass grafting in patients with a moderate to severely decreased left ventricular ejection fraction.

METHODS

Between 1997 and 1998, 75 consecutive patients with moderate to severe left ventricular dysfunction underwent coronary artery bypass grafting procedures. The operative mortality rate was 4.0%, and the 72 survivors were monitored for 8 years. The end points were mortality, symptomatic status (New York Heart Association [NYHA] functional class), and left ventricular function.

RESULTS

The total survival rate after 8 years was 89.3%. During follow-up, 8 patients died. Death was attributed to a cardiac cause in 5 patients and to a noncardiac cause in 3. There was no statistically significant difference between preoperative and late postoperative NYHA functional class, despite a statistically significant improvement that persisted for up to 4 years after CABG. The results of echocardiography showed a statistically significant improvement in the left ventricular ejection fraction (from 0.322 +/- 0.06 preoperatively to 0.463 +/- 0.02 at follow-up, p < 0.001). Multivariate analysis revealed that the left ventricular end-systolic volume index, the presence of angina pectoris, and absence of symptoms of congestive heart failure were preoperative indicators of freedom from heart failure after coronary operations (p < 0.05).

CONCLUSIONS

Coronary artery bypass grafting for patients with moderate-to-severe left ventricular dysfunction is associated with acceptable long-term results. The left ventricular end-systolic volume index is a simple noninvasive method to aid in the preoperative decision making in such patients.

[Predictors of improved left ventricular systolic function after surgical revascularization in patients with ischemic cardiomyopathy]

INTRODUCTION AND OBJECTIVES

Although it is known that the presence of myocardial viability predicts an increase in ejection fraction after revascularization in patients with ischemic cardiomyopathy, little is known about other predictive factors. The aim of this study was to identify variables that can predict an increase in ejection fraction after coronary revascularization surgery in patients with ischemic cardiomyopathy and a viable myocardium.

METHODS

The study included 30 patients (mean age 61.6 [11] years, one female) with ischemic cardiomyopathy (ejection fraction <or=40%) who fulfilled criteria for myocardial viability. All underwent ECG-gated single-photon emission computed tomography before and after surgery.

RESULTS

An increase in ejection fraction >or=5% occurred after surgery in 17 of the 30 patients (56.6%). These patients were characterized by the presence of left main coronary artery disease (P< .004), a large number of grafts (P< .03), a high perfusion summed difference score (P< .012), a low end-diastolic volume (P< .013), and a low end-systolic volume (P< .01). An end-systolic volume <148 mL and a summed difference score >or=4 gave the best predictive model (P=.001, R2=0.73) for an increase in ejection fraction.

CONCLUSIONS

In patients with ischemic cardiomyopathy and a viable myocardium, the main determinants of an increase in ejection fraction after revascularization surgery were low levels of left ventricular remodeling and myocardial ischemia.

Mechanisms leading to reversible mechanical dysfunction in severe CAD: alternatives to myocardial stunning

Patients with severe chronic coronary artery disease (CAD) exhibit a highly altered myocardial pattern of perfusion, metabolism, and mechanical performance. In this context, the diagnosis of stunning remains elusive not only because of methodological and logistic considerations, but also because of the pathophysiological characteristics of the myocardium of these patients. In addition, a number of alternative pathophysiological mechanisms may act by mimicking the functional manifestations usually attributed to stunning. The present review describes three mechanisms that could theoretically lead to reversible mechanical dysfunction in these patients: myocardial wall stress, the tethering effect, and myocardial expression and release of auto- and paracrine agents. Attention is focused on the role of these mechanisms in scintigraphically “normal” regions (i.e., regions usually showing normal perfusion, glucose metabolism, and cellular integrity as assessed by nuclear imaging techniques), in which stunning is usually considered, but these mechanisms could also operate throughout the viable myocardium. We hypothesize that reversion of these three mechanisms could partially explain the unexpected functional benefit after reperfusion recently highlighted by high-spatial-resolution imaging techniques.

Does resting two-dimensional echocardiography identify patients with ischemic cardiomyopathy and low likelihood of functional recovery after coronary revascularization?

OBJECTIVE

To evaluate the potential of a simple and widely available technique as two-dimensional (2D) echocardiography to identify patients with ischemic cardiomyopathy and low likelihood of functional recovery after coronary revascularization.

METHODS

Two-dimensional echocardiography and radionuclide ventriculography (RNV) were performed before coronary revascularization in 94 patients with ischemic cardiomyopathy. Left ventricular ejection fraction (LVEF) was measured by RNV. Regional wall motion abnormalities, wall motion score index, end-diastolic wall thickness (EDWT), left ventricular (LV) volumes and LV sphericity index were assessed in the echocardiographic images. RNV was repeated 9-12 months after revascularization to assess LVEF change; an improvement >or=5% was considered clinically significant.

RESULTS

Nine hundred and ninety-nine segments were severely dysfunctional; 149 out of 999 (15%) had an EDWT <or=6 mm. A severe enlargement of the end-diastolic volume index (EDVI) (>or=100 ml/ml) and of the end-systolic volume index (>or=80 ml) was present in 32 (34%) and 21 (22%) patients, respectively. A spherical shape of the LV was observed in 35 (37%) patients. LVEF after revascularization increased in 30 out of 94 patients (32%) from 30+/-8% to 39+/-9% (P<0.0001). On multivariate analysis, the EDVI was the only predictor of no recovery in LVEF [odds ratio, 1.06, confidence interval (CI), 1.04-1.1, P<0.0001]. The cut-off value of EDVI >or=90 ml/ml accurately identified patients that virtually never recover. Post-operatively, LVEF increased in three out of 42 (7%, 95% CI 0-15%) patients with EDVI >or=90 ml/ml as compared to 27 out of 52 (52%) patients with EDVI<90 ml/ml (P<0.0001).

CONCLUSIONS

In patients with ischemic cardiomyopathy and severe LV enlargement, improvement of LVEF after revascularization is unlikely to occur. Conversely, in patients with relatively preserved LV size, a higher likelihood of functional recovery may be anticipated.

Why do patients with ischemic cardiomyopathy and a substantial amount of viable myocardium not always recover in function after revascularization?

OBJECTIVE

In patients with ischemic cardiomyopathy and a substantial amount of dysfunctional but viable myocardium, myocardial revascularization may improve left ventricular ejection fraction. The aim of this study was to evaluate why not all patients with a substantial amount of viable tissue recover in function after revascularization.

METHODS

A total of 118 consecutive patients with a depressed left ventricular ejection fraction (on average 29% +/- 6%) due to chronic coronary artery disease underwent myocardial revascularization. Before revascularization all patients underwent dobutamine stress echocardiography to assess regional dysfunction, left ventricular volumes, and myocardial viability as well as radionuclide ventriculography to determine the left ventricular ejection fraction. Next, 3 to 6 months after revascularization, the left ventricular ejection fraction and regional contractile function were reassessed. Improvement of left ventricular ejection fraction > or = 5% following revascularization was considered clinically significant.

RESULTS

Dobutamine stress echocardiography revealed that 489 (37%) of the 1329 dysfunctional segments were viable. A total of 61 (52%) patients had a substantial amount of viable myocardium (> or = 4 viable segments). In these 61 patients the global function was expected to recover > or = 5% after revascularization. However, left ventricular ejection fraction did not improve in 20 (33%) of 61 patients despite the presence of substantial viability. Clinical characteristics and echocardiographic data were comparable between patients with and without improvement. However, patients without improvement had considerably larger end systolic volumes (153 +/- 41 mL vs 133 +/- 46 mL, P =.007). The likelihood of recovery of global function decreased proportionally with the increase of end systolic volume (P <.001, R = 0.43, n = 61). Receiver operating characteristic curve analysis demonstrated that an end systolic volume > or = 140 mL had the highest sensitivity/specificity to predict the absence of global recovery.

CONCLUSIONS

In patients with ischemic cardiomyopathy not only the amount of dysfunctional but viable myocardium but also the extent of left ventricular remodeling determines the improvement in function following myocardial revascularization. Patients with a high end systolic volume due to left ventricular remodeling have a decreased likelihood of improvement of global function.

Utility of positron emission tomography in predicting improved left ventricular ejection fraction after coronary artery bypass grafting among patients with ischemic cardiomyopathy

The objective of this study was to determine whether preoperative estimates of regional myocardial uptake of (18)-F-fluorodeoxyglucose (FDG) could predict postoperative improvement in ejection fraction in patients undergoing coronary artery bypass grafting (CABG) for ischemic cardiomyopathy. 20 consecutive patients [left ventricular ejection fraction (LVEF) </=27%] were referred for preoperative positron emission tomography (PET) to measure regional myocardial FDG uptake and were deemed candidates for CABG. All individuals had technically adequate vessels and significant viability. The left anterior descending (LAD) coronary artery was severely diseased in all patients. Because of the importance of the anterior wall to overall ventricular performance, FDG uptake was semiquantitated in those regions and related to postoperative LVEF. 17 patients underwent CABG with an uneventful recovery. LVEF increased from 22 +/- 4 to 26 +/- 7% 2 weeks postsurgery (p < 0.05), with >/=5% change noted in 7 patients (group 1) and <5% noted in 10 patients (group 2). No preoperative or perioperative clinical variable could predict those with improved ventricular function. The relative amount of FDG uptake in the anterior wall was higher in group 1 compared with group 2 (93 +/- 9 vs. 81 +/- 13%; p < 0.05) and correlated with the change in LVEF post-CABG (r = 0.50; p < 0.05). >88% of FDG uptake in the LAD region had a positive predictive accuracy of 67% and negative predictive accuracy of 88% for improved LVEF postbypass. Late follow-up estimates of LVEF (median of 10 months) showed that early changes in function were sustained. In summary, among patients with severe coronary artery disease and depressed LVEF, ventricular function may improve early postrevascularization. PET estimates of relative FDG uptake in the anterior wall help predict those individuals who are likely to have the greatest increment in LVEF.

Does the extended use of arterial grafts compromise the myocardial recovery after coronary artery bypass grafting in left ventricular dysfunction?

OBJECTIVE

To assess the prognostic factors of myocardial recovery expected after coronary bypass surgery and the impact of surgical technique used, a prospective non-randomized study including a 1-year postoperative evaluation of left ventricular function was performed in patients with left ventricular dysfunction (left ventricular ejection fraction (LVEF) < 0.40).

METHODS

From 1993 to 1996, 110 patients (mean age 61+/-11 years) were included in the study. The mean LVEF was 31+/-6%. All patients had preoperative radionuclide investigations based on the combination of stress/reinjection thallium single photon emission computed tomography (SPECT) and planar evaluation of LVEF; 88% of patients had reversible ischemic thallium defects. Two surgical technique were used: 53 patients received the left internal mammary artery with associated sequential vein graft, and 57 patients received only arterial grafts, internal mammary and gastroepiploic arteries. The mean number of distal anastomoses was 3.2+/-0.8 and 54% of patients had complete revascularization. At 1 year, all survivors had clinical evaluation and the same radionuclide investigations.

RESULTS

The early mortality was 2.7%. At 1 year, 100 patients were surviving; on average, NYHA class decreased 1.9+/-0.8 to 1.4+/-0.6 (P < 0.01) and CCS class from 2.8+/-0.6 to 1+/-0.3 (P < 0.01). The mean LVEF increase from 31+/-9 to 34+/-10% (P < 0.01) and the mean LV end-diastolic volume decreased from 317+/-112 to 285+/-108 ml (n.s.). The postoperative improvement in LV function was higher in patients in NYHA class 3 or 4 before surgery (P < 0.05), when associated sequential vein graft had been used (P < 0.01), and in patients with low preoperative LVEF (P < 0.01). The postoperative LVEF improvement observed was significantly correlated with the improvement in left ventricular end-diastolic (LVED) volume and the improvement in redistribution/reinjection thallium uptake. Multivariate analysis showed that the surgical technique used and the preoperative LVEF were independent prognostic factors of the postoperative myocardial function recovery, with a significant positive impact of the vein use.

CONCLUSION

This study confirms the excellent clinical results of coronary artery bypass grafting (CABG) in patients with coronary artery disease and LV dysfunction; improvement in LV function can be documented objectively and is correlated with reperfusion of hibernating myocardium. However, the extended use of arterial grafts does not allow to achieve the significant myocardial recovery observed with the use of one internal mammary artery (IMA) and associated sequential vein graft; it seems to be related to the preoperative selection of patients, but a direct negative impact of arterial grafts was documented and leads to be cautious in patients with severe LV dysfunction.

Efficacy of coronary artery bypass grafting in patients with a dilated left ventricle due to myocardial infarction

This study was designed to clarify the efficacy of coronary artery bypass grafting (CABG) on left ventricular (LV) function in 16 patients with a dilated LV due to myocardial infarction (LV end-systolic volume index: LVESVI >60 ml/m2). All had attained complete revascularization. To estimate the LV wall motion quantitatively using echocardiography, a wall motion score (WMS) was used (LV was divided into 17 segments with a four-point scale: akinesis=3, severe hypokinesis=2, hypokinesis=1, normal=0 and then summed). Exercise stress tests were performed after surgery, revealing that anginal symptoms had vanished in all the patients. In 5 patients with a preoperative end-systolic volume index (ESVI) >100 ml/m2, the ejection fraction (EF) did not change, and both were under 30% (before to after: 26+/-4 to 26+/-4%). Neither the ESVI (148+/-50 to 133+/-39 ml/m2) nor the end-diastolic volume index (end-diastolic volume index (EDVI): 198+/-62 to 180+/-37 ml/m2) changed; the WMS did not change (33+/-2 to 33+/-3). During exercise, in spite of the increase in heart rate (HR) (at rest, 81+/-20; HR during exercise, 111+/-21 beats/min, p<0.005) and LV end-diastolic pressure (EDP) (22+/-9; 35+/-13 mmHg, p<0.02), both cardiac index (CI) (2.4+/-0.3; 2.6+/-0.4 L/min x m2) and minute work (MW: 4.0+/-1.1; 4.1+/-0.4 kg x M/min) did not increase. In 11 patients with a preoperative ESVI <100 ml/m2, EF was extremely increased in 5 patients (more than 10%, 35+/-4 to 60+/-6%, p<0.005=improved subgroup) in whom the EDVI (130+/-16 to 120+/-13 ml/m2) did not change whereas the ESVI (82+/-14 to 48+/-7 ml/m2) was reduced. However, in the 6 remaining patients (ie nonimproved subgroup), neither ESVI (78+/-8 to 74+/-12 ml/m2), EDVI (115+/-10 to 115+/-20 ml/m2) nor EF (31+/-7 to 35+/-3%) changed. During exercise, HR (at rest, 88+/-13; during exercise, 108+/-11 beats/min, p<0.005), LVEDP (20+/-6; 29+/-7 mmHg, p<0.01), CI (2.5+/-0.6; 3.3+/-0.5 L/min x m2, p<0.05), MW (4.6+/-1.0; 6.5+/-1.5 kg x M/min, p<0.05) increased. The WMS in the nonimproved subgroup did not change (29+/-6 to 27+/-2), but in the improved subgroup it reduced after surgery (27+/-3 to 19+/-4, p<0.01). These data suggested that CABG in patients with a dilated LV was effective against anginal symptoms, but was restricted to left ventricular function. It may be possible to estimate postoperative LV function, including exercise tolerance, from the preoperative LVESVI.

Left ventricular volume predicts postoperative course in patients with ischemic cardiomyopathy

BACKGROUND

The left ventricular end-systolic volume index (LVESVI) helps to predict postoperative left ventricular function in patients with ischemic cardiomyopathy.

METHODS

We retrospectively assessed the ability of preoperative variables to predict death and the development of postoperative congestive heart failure in 41 patients with a preoperative ejection fraction of less than 0.30.

RESULTS

A preoperative LVESVI of greater than 100 mL/m2 was identified as an independent predictor of death by Cox's proportional hazards model. Diabetes and a preoperative LVESVI of greater than 100 mL/m2 were independent predictive risk factors for the development of postoperative congestive heart failure. Postoperative congestive heart failure developed in 2 of the 23 patients (8.7%) who had a preoperative LVESVI of less than 100 mL/m2 and in 10 of the 16 patients (62.5%) who had a preoperative LVESVI of greater than 100 mL/m2. The actuarial survival rate during follow-up in patients who had a preoperative LVESVI of less than 100 mL/m2 was significantly greater than that in patients who had a preoperative LVESVI of greater than 100 mL/m2. The actuarial rate of freedom from congestive heart failure during the follow-up period also was greater in patients who had a preoperative LVESVI of less than 100 mL/m2.

CONCLUSIONS

Our results suggest that the preoperative LVESVI predicts the development of postoperative congestive heart failure and the actuarial survival rate in patients with ischemic cardiomyopathy.