Determinants of mid- and long-term results in patients after surgical revascularization for ischemic cardiomyopathy

Impact of complete revascularization in coronary artery bypass grafting for ischemic cardiomyopathy

Objective

In patients with ischemic cardiomyopathy, coronary artery bypass grafting ensures better survival than medical therapy. However, the long-term clinical impact of complete revascularization remains unclear. This observational study aimed to evaluate the effects of complete revascularization on long-term survival and left ventricular functional recovery in patients with ischemic cardiomyopathy undergoing coronary artery bypass grafting.

Methods

We retrospectively reviewed outcomes of 498 patients with ischemic cardiomyopathy who underwent complete (n = 386) or incomplete (n = 112) myocardial revascularization between 1993 and 2015. The baseline characteristics were adjusted using inverse probability of treatment weighting to reduce the impact of treatment bias and potential confounding. The mean follow-up duration was 77.2 ± 42.8 months in survivors.

Results

The overall 5-year survival rate (complete revascularization, 72.5% vs incomplete revascularization, 57.9%, P = .03) and freedom from all-cause death and/or readmission due to heart failure (54.5% vs 40.1%, P = .007) were significantly greater in patients with complete revascularization than those with incomplete revascularization. After adjustments using inverse probability of treatment weighting, the complete revascularization group demonstrated a lower risk of all-cause death (hazard ratio, 0.61; 95% confidence interval, 0.43-0.86; P = .005) and composite adverse events (hazard ratio, 0.59; 95% confidence interval, 0.44-0.79; P < .001) and a greater improvement in the left ventricular ejection fraction 1-year postoperatively (absolute change: 11.0 ± 11.9% vs 8.3 ± 11.4%, interaction effect P = .05) than the incomplete revascularization group.

Conclusions

In patients with ischemic cardiomyopathy undergoing coronary artery bypass grafting, complete revascularization was associated with better long-term outcomes and greater left ventricular functional recovery and should be encouraged whenever possible.

Comparison between normothermic and mild hypothermic cardiopulmonary bypass in myocardial revascularization of patients with left ventricular dysfunction

AIMS

The aim of this study was to investigate whether normothermic bypass is superior to mild hypothermia in patients with poor left ventricular function. This was achieved by studying defibrillation rates, postoperative requirements of cardiac pacing or other morbidity issues and mortality in patients with left ventricular dysfunction operated upon for elective coronary revascularization.

METHODS

Data were collected retrospectively from 252 consecutive patients with left ventricular dysfunction (ejection fraction ≤35%) undergoing coronary revascularization between January 2005 and January 2011. Patients operated upon under mild hypothermia (32 ºC) were placed in Group 1 and under normothermia (≥35 ºC) were placed in Group 2. Comorbidities and postoperative complications were recorded.

RESULTS

There were 128 patients in Group 1 and 124 patients in Group 2. Plasma concentrations of CK-MB and troponin T peaked at 6 hours postoperatively, with no significant difference between the groups. Despite longer aortic cross-clamp time and total bypass time in Group 2, significantly less defibrillation requirement rates after aortic declamping was observed. Hospital mortality occured in 16 patients; 8 patients in each group.

CONCLUSIONS

Normothermia enables less requirement for defibrillation after aortic declamping and postoperative cardiac pacing in patients with left ventricular dysfunction, which may be interpreted as better myocardial protection under normothermic bypass. However, maintaining normothermia had no effect on postoperative stroke, postoperative atrial fibrillation, renal failure development and mortality.

Off-pump Coronary Bypass Surgery in Patients with Low Ejection Fraction

Objective

Long-term survival after off-pump surgery in patients with low ejection fraction was investigated.

Methods

Three hundred forty-six patients with ejection fraction 30% or less with isolated off-pump coronary artery bypass surgery (OPCAB) were compared with a propensity matched historical group operated on-pump (ONCAB) and with data from literature after percutaneous coronary intervention and OPCAB surgery.

Results

The lower invasiveness of OPCAB contributed to a significantly better 30-day survival, shorter postoperative length of stay, and fewer in-hospital complications. Incomplete revascularization of the posterior and lateral territories of the heart correlated with higher 1-year mortality. The probability of survival for 8 years after OPCAB was 50.1% (n = 76) versus 49.7% (n = 82) for ONCAB without comparable data from literature for OPCAB or percutaneous coronary intervention in these high-risk patients.

Conclusions

OPCAB surgery in patients with low ejection fraction is a viable alternative but so far without demonstrable long-term survival advantage to ONCAB.

Surgical left ventricular remodeling leads to better long-term survival and exercise tolerance than coronary artery bypass grafting alone in patients with moderate ischemic cardiomyopathy

OBJECTIVES

Optimal treatment strategies for patients with ischemic cardiomyopathy and moderately reduced left ventricular function remain controversial. We assessed the early and midterm outcomes after surgical revascularization alone versus revascularization and additional left ventricular remodeling in these patients.

METHODS

Between 2000 and 2003, 285 consecutive patients with coronary artery disease and moderately impaired left ventricular function (ejection fraction 30%-40%) were surgically treated with coronary artery bypass grafting alone (group 1, n = 165) or open left ventricular remodeling in addition to revascularization (group 2, n = 120). Preoperatively, the New York Heart Association class, left ventricular ejection fraction, and end-diastolic diameter were comparable. Early and midterm outcomes, hemodynamic performance, and quality of life assessed by Minnesota Quality of Life Questionnaire were evaluated during a mean follow-up period of 70 months.

RESULTS

Group 2 patients demonstrated significantly longer ventilation times, higher blood loss, and need for blood transfusion but had significantly lower operative mortality (4.5% compared with 8.5% in group 1). Seven-year follow-up demonstrated survival of 74.3% +/- 8.1% in group 1 versus 84.2% +/- 5.4% in group 2 (P < .05). Follow-up examinations revealed greater improvement of functional class in group 1 with mean 1.7 +/- 0.7 versus 2.03 +/- 0.8 in group 2 (P < .05). Cardiac-related hospital readmissions were comparable (3.8% vs 4.1%, P = .73).

CONCLUSIONS

Patients with ischemic cardiomyopathy, in whom surgical ventricular remodeling was possible and performed, experienced more perioperative complications but had superior early and midterm outcome regarding survival, functional class, and quality of life.

Coronary Artery Bypass for Heart Failure in Ischemic Cardiomyopathy: 17-Year Follow-Up

BACKGROUND

Coronary artery bypass grafting (CABG) has been safely extended to ischemic cardiomyopathy and heart failure, but outcome beyond 5 years remains poorly defined.

METHODS

We retrospectively analyzed 45 consecutive angina-free patients with ischemic left ventricular dysfunction (ejection fraction < or = 0.35) and heart failure (New York Heart Association functional class III to IV) who were selected for CABG between 1988 and 1995. Positron emission tomography was used for preoperative identification of myocardial viability.

RESULTS

The 30-day mortality was 4.4%. At a median follow-up of 117 months (longest observation, 205 months), the probability of survival at 1, 5, 10, and 15 years after CABG was 93.3%, 84%, 65%, and 44%, respectively. At multivariable analysis, a left ventricular end-diastolic pressure (LVEDP) of 25 mm Hg or more predicted a threefold increase of the hazard of death (p = 0.02), whereas a LVEDP of 20 mm Hg or more correlated with the requirement of an intraaortic balloon pump perioperatively (p = 0.04). Other independent predictors of survival were age older than 70 years and peripheral vascular disease. Cardiac events accounted for 88% of late deaths, which were primarily related to sudden death or progressive heart failure. Most patients were in New York Heart Association functional class I to II at late follow-up.

CONCLUSIONS

CABG alone yields good long-term outcome in selected angina-free patients with ischemic systolic dysfunction and advanced heart failure. However, associated diastolic impairment, reflected by elevated LVEDP, predicts reduced long-term survival despite myocardial viability.

[Assessment of tissue viability for improvement of the left ventricular function after revascularization]

INTRODUCTION

Treatment of patients with heart failure following myocardial infarction is still a clinical challenge. Drug therapy in these patients is limited, and invasive revascularization is not always successful and does not guarantee desired results. The aim of this study was to compare the effectiveness of invasive revascularization procedures (coronary artery bypass grafting - CABG or percutaneous transluminal coronary angioplasty - PTCA) with conventional drug therapy in patients with heart failure after acute myocardial infarction in whom significant portion of viable myocardial tissue was detected during low dose dobutamine stress echocardiography.

MATERIAL AND METHODS

Using a prospective analysis, we investigated 66 patients with heart failure following myocardial infarction and reduced left ventricular ejection fraction (LVEF <35%). 34 patients underwent revascularization procedures including CABG or PTCA. The other 32 patients received only conventional drug therapy. The patients were followed during 12 months examing LVEF, left ventricular wall motion score index (WMSI), NYHA functional class, and cardiac death.

RESULTS

After 12 months, patients undergoing revascularization procedures presented with significantly better functional improvement of LVEF (37.84% vs. 33.14%, p<0.05), better clinical status and significantly less cardiac deaths (8.82% vs. 21.87%, p<0.01) in comparison to patients who stayed on drug therapy. After 12 months WMSI was significantly better in patients who underwent interventional therapy (1.69 +/- 07 vs. 1.82 +/- 04, p<0.01).

CONCLUSION

After a 12-month follow up period, patients with presence of viable myocardial tissue after myocardial infarction and undergoing revasculkatization procedures presented with better functional recovery and less cardiac events, including cardiac death, in comparison with patients who received only drug therapy.

Impact of No-to-Moderate Mitral Regurgitation on Late Results After Isolated Coronary Artery Bypass Grafting in Patients With Ischemic Cardiomyopathy

BACKGROUND

This study analyzes retrospectively a cohort of patients with ischemic cardiomyopathy (ejection fraction < or = 0.30) who underwent isolated coronary artery bypass grafting to evaluate the impact of no-to-moderate mitral regurgitation (MR) on long-term results.

METHODS

From January 1988 to December 2002, 6,108 patients had isolated coronary artery bypass grafting. Two hundred thirty-nine (3.9%) had ischemic cardiomyopathy; 60 patients had no, 102 had mild, and 77 had moderate MR. Using propensity score, a group of 70 patients with no or mild MR (group A) was case-matched with a group of 70 patients with moderate MR (group B) to obtain two groups with similar preoperative characteristics.

RESULTS

Nine patients (6.4%) died within the first 30 days; all deaths were cardiac-related. There was no difference in the early results between groups. Patients in group B showed lower freedom from death, from cardiac death, from cardiac death and ischemic events, and from death and New York Heart Association class III and IV than patients in group A. Cox analysis confirmed that moderate MR was an independent variable for worse late outcome in this subgroup of patients. Functional and echocardiographic results, after a mean of 62 +/- 28 months in 87.8% of survivors, showed a significant impairment of New York Heart Association class (from 2.2 +/- 0.5 to 2.8 +/- 0.6; p < 0.001) and MR degree (from 2.0 to 2.7 +/- 1.0; p = 0.023) in patients with preoperative moderate MR.

CONCLUSIONS

This study confirms that moderate ischemic MR has an important negative impact on survival and quality of life of patients with severely impaired left ventricular function, treated by coronary artery bypass grafting alone.

Myocardial Revascularization in Patients with Low Ejection Fraction <=35%: Effect of Pump Technique on Early Morbidity and Mortality

BACKGROUND AND AIM

Left ventricular dysfunction is an important predictor of in-hospital mortality. Surgical risk among these patients remains high. The present study is conducted to evaluate the difference in early morbidity and mortality among patients with compromised left ventricular function (LVF) after myocardial revascularization using either off-pump or on-pump coronary artery bypass graft.

METHODS

Between April 2000 and April 2004, 150 patients with ejection fraction (EF) < or =35% underwent isolated coronary artery bypass grafting. Eighty-four patients underwent conventional bypass (mean EF 30.1%+/- 4.2) and 66 patients had off-pump coronary artery bypass (mean EF 27.5%+/- 5.5). Different variables (preoperative, intraoperative, and postoperative) were evaluated and compared. Determination of operation risk was done using EuroSCORE. Patients who underwent OPCAB were more risky due to a high percentage of associated comorbidities, mean EuroSCORE was 12.96 +/- 13.21 in comparison to 8.47 +/- 10.22 in CCAB.

RESULTS

The mean operative mortality was 8.7%. Patients who underwent OPCAB had a lower operative mortality than CCAB (6.1% vs. 10.7%) inspite of a higher preoperative predicted risk score. Completeness of revascularization was higher among the CCAB group (85.7% vs. 69.7%; p = 0.01). Subsequently, the mean number of grafts was significantly higher among this group (3.4+/-0.7 vs. 2.0 +/-0.9; p < 0.001). On the other hand, morbidity was significantly higher in CCAB (35.7% vs. 19.7%; p = 0.03). However, the incidence of both myocardial infarction and atrial fibrillation was more among OPCAB.

CONCLUSIONS

Patients with left ventricular dysfunction are high-risk group. These patients can benefit from myocardial revascularization using either off-pump or conventional CABG, but both are associated with a higher mortality and morbidity than those with normal ventricle. The use of off-pump CABG resulted in better clinical outcome and mortality, but less number of grafts performed than those with conventional CABG especially in patients with lowest EF.

Coregistered MR Imaging Myocardial Viability Maps and Multi–Detector Row CT Coronary Angiography Displays for Surgical Revascularization Planning: Initial Experience

PURPOSE

To evaluate assignment of left ventricular (LV) myocardial segments to coronary arterial territories by using coregistered magnetic resonance (MR) imaging and multi-detector row computed tomography (CT) displays; to assess the accuracy of coregistered displays in determining the distribution of clinically important coronary artery disease (CAD) and regional effect of CAD on LV myocardium in patients with chronic ischemic heart disease (CIHD); and to determine the utility of coregistered displays in optimizing surgical revascularization planning.

MATERIALS AND METHODS

This study was HIPAA compliant and was approved by the local Institutional Review Board, with waiver of informed consent. Twenty-six patients (19 men, seven women; age, 56 years +/- 12 [+/- standard deviation]) with CIHD underwent MR imaging assessment of myocardial viability and multi-detector row CT assessment of CAD on the same day. For coregistration, a population-based LV model was fit to each data set separately; models were then registered spatially. For data analysis, correspondence between coregistered displays and the 17-segment LV model for assessment of CIHD was evaluated, accuracy of using coregistered displays to evaluate the extent of CAD and myocardial disease was assessed, and utility of coregistered displays in optimizing surgical revascularization planning was determined.

RESULTS

Coronary assignment for coregistered displays and the 17-segment LV model differed in 17% of myocardial segments. For the majority of patients, three segments (midanterolateral [62%], apical lateral [73%], and apical inferior [58%]) were discordant. Segments were supplied by the left anterior descending artery, a diagonal branch, or a ramus intermedius with diagonal distribution in all but one case. Coregistered displays were deemed concordant with selective coronary angiography and alternate myocardial imaging in all cases. Overall, surgical planning was potentially enhanced in 83% of cases because, compared with alternate imaging modalities, coregistered displays were believed to demonstrate the relationship between coronary arteries and underlying myocardial tissue more definitively and efficiently (for patients in whom surgery was performed) or more correctly and comprehensively (for a presumably better-tailored surgery).

CONCLUSION

Assessment of CIHD can be improved by using coregistered displays that directly relate the condition of LV myocardium to the anatomy of the coronary arteries in individual patients.

What is the evidence for percutaneous coronary intervention or coronary artery bypass graft in ischemic cardiomyopathy?

Coronary artery disease has supplanted hypertension as the leading cause of congestive heart failure in the United States. The recognition that contraction abnormalities could accrue from gradual stunning, or longer-term 'hibernation,' raised the possibility that revascularization of viable but hypocontractile elements could improve myocardial performance. This review focuses on the data from randomized trials and registries regarding the potential benefits and risks of either coronary artery bypass grafting (CABG) or percutaneous coronary intervention for patients with severe left ventricular dysfunction secondary to coronary artery disease. For patients with medically refractory angina and ischemic cardiomyopathy, revascularization with CABG or percutaneous coronary intervention is recommended. The ongoing National Institutes of Health-sponsored Surgical Treatment for Ischemic Heart Failure (STICH) trial, a multicenter, prospective, randomized trial comparing contemporary medical therapy with CABG for patients with ischemic cardiomyopathy, should provide important information regarding patients who do not have angina. The conclusion of this review is that a trial of medical therapy vs. percutaneous coronary intervention could be of additional value, especially for patients at particularly high risk, when undergoing CABG.

Complete myocardial revascularization: between myth and reality

Myocardial revascularization in patients with multi-vessel coronary artery disease may be accomplished, by percutaneous interventions or surgery, either on all diseased lesions or directed to selectively targeted coronary segments. The extent of planned revascularization is often a major determinant of treatment strategy. Revascularization of all diseased coronary segments-complete myocardial revascularization-has a potential long-term benefit, but is more complex and may increase in-hospital untoward events. Revascularization may otherwise be incomplete, either because of the operator's inability to treat all diseased coronary segments or by choice of deciding to selectively revascularize only large areas of myocardium at risk. Although incomplete revascularization may negatively affect long-term outcomes, it may be, when wisely chosen, the preferred treatment strategy in selected patient categories because of its lower immediate risks. The patient's clinical status, ventricular function, and the presence of co-morbidities may orient clinical decisions in favour of incomplete revascularization.

Nontransplant surgical options for congestive heart failure

Although advanced heart failure has been considered the main indication for heart transplantation, the increasing number of candidates and shortage of organs for transplantation, with accumulating waiting lists, has originated another look into more conventional surgery, previously considered of prohibitive risk. In fact, many cases are a result of anatomic lesions that can be corrected by conventional surgery, and in the past decade many surgical groups have obtained good and even excellent results in the treatment of aortic stenosis with low output, and in aortic and mitral regurgitation with severe left ventricular (LV) dysfunction. Also, ischemic and idiopathic dilated cardiomyopathy have been successfully treated by several types of LV remodeling surgery, with or without coronary grafting. Many of these procedures achieved excellent operative, medium-, and long-term results and survival, which match well those observed with cardiac transplantation, most often with advantages in the quality of life and, not unimportantly, in financial costs. For operated patients, especially those with ischemic cardiomyopathy, close follow-up for cardiac failure is extremely important in order to detect the right moment for heart transplantation, if it becomes necessary.