Coronary artery bypass grafting in patients with chronic congestive heart failure: a 10-year experience with 203 patients

Coronary artery bypass grafting in patients with left ventricular dysfunction

BACKGROUND

Coronary artery bypass grafting surgery (CABG) remains a challenge for patients with coronary artery disease and left ventricular (LV) dysfunction. The aim of this study was to evaluate the result of CABG in patients with LV dysfunction.

METHODS

Medical records of 1,847 patients who underwent primary, isolated CABG at Taipei Veterans General Hospital from January 1, 1991 to December 31, 2002, were reviewed. The mortality rate associated with clinical and operative variables was compared between patients with LV ejection fraction (LVEF) > or = 35% and patients with LVEF < 35%.

RESULTS

Patients with LVEF < 35% had more episodes of myocardial infarction (57.5% vs 28.9%, p < 0.001) and history of congestive heart failure (18.1% vs 3.2%, p < 0.001), higher New York Heart Association (NYHA) class, and higher angina class. Longer cardiopulmonary bypass time (147 +/- 44 minutes vs 137 +/- 40 minutes, p < 0.001) but fewer left internal mammary artery (LIMA) grafts (46.8% vs 65.7%, p < 0.001) were used in patients with LVEF < 35%. Patients with LVEF < 35% had significantly higher hospital mortality (6.6% vs 2.2%, p < 0.001), higher major morbidity (23.3% vs 16.1%, p < 0.01), and longer hospital stay (25 +/- 23 days vs 21 +/- 16 days, p < 0.01).

CONCLUSION

Although patients with LV dysfunction had higher mortality and morbidity, CABG could be done in these high-risk patients with acceptable results.

Is the use of cardiopulmonary bypass for multivessel coronary artery bypass surgery an independent predictor of operative mortality in patients with ischemic left ventricular dysfunction?

BACKGROUND

l Coronary artery bypass grafting for patients with ischemic left ventricular dysfunction (ILVD) remains superior to medical therapy in terms of long-term survival. Recently, off-pump coronary artery bypass surgery has been shown to be very promising in achieving functional improvements with favorable operative mortality in this challenging group of patients. The aim of this study was to assess the risk factors responsible for operative mortality in this group of patients.

METHODS

The records of 305 consecutive ILVD patients, who underwent primary isolated coronary artery bypass grafting for multivessel disease at The National Heart and Lung Institute, Imperial College, University of London, between January 1999 and January 2002, were reviewed retrospectively. Patients were considered to have ILVD if they had a left ventricular ejection fraction of 0.30 or less on preoperative coronary angiography. One hundred six patients were operated on using the off-pump coronary artery bypass surgery technique, and 199 patients were operated on using the conventional coronary artery bypass grafting technique with cardiopulmonary bypass. RESU;TS: Seven (6.6%) patients died in the off-pump coronary artery bypass surgery group, whereas 28 (14.1%) patients died in the cardiopulmonary bypass group (p = 0.05). Univariate analysis of all the preoperative characteristics was performed to identify the potential predictors of mortality in the whole group of ILVD patients. Potential predictors of mortality included symptom status (stable/unstable), chronic obstructive airway disease, dyspnea grade III and IV on the New York Heart Association classification, intravenous nitrates, preoperative use of intraaortic balloon pump, ventricular tachycardia or ventricular fibrillation, body surface area less than 2, and cardiopulmonary bypass. Only ventricular tachycardia or ventricular fibrillation was proved to act as an independent predictor of operative mortality in this group of ILVD patients, with an odds ratio of 29.6 (95% confidence interval, 8.9 to 98).

CONCLUSIONS

This study showed that using cardiopulmonary bypass for multivessel coronary artery bypass grafting in patients with ILVD was not proved to act as an independent predictor of operative mortality.

Coronary surgery with non-cardioplegic methods in patients with advanced left ventricular dysfunction: immediate and long term results

OBJECTIVE

To evaluate perioperative results and long term survival in patients with severe left ventricular (LV) dysfunction undergoing coronary artery bypass grafting (CABG) using non-cardioplegic methods.

METHODS

From April 1990 through December 1999, 4100 consecutive patients underwent isolated CABG using hypothermic ventricular fibrillation. Of these, 141 (3.4%) had severe LV dysfunction (ejection fraction < 30%). Mean age was 58.3 (9.6) years. 64 patients (45.4%) were in Canadian Cardiovascular Society class III or IV and 16 (11.3%) were subjected to urgent or emergent surgery. A previous myocardial infarction was recorded in 127 (90.1%). The majority (89.4%) had triple vessel and 26 (18.4%) had left main disease. The mean number of grafts per patient was 3.1. At least one internal thoracic artery was used in all patients and 21 (14.8%) had bilateral internal thoracic artery grafts (1.2 arterial grafts per patient).

RESULTS

Perioperative mortality was 2.8% (4 patients) and the incidence of acute myocardial infarction 2.8%. 50 (35.5%) patients required inotropes but only 16 (11.3%) required it for longer than 24 hours; 5 patients (3.5%) needed mechanical support. The incidence of renal failure was 3.5%. Mean duration of hospital stay was 9.6 (8.3) days. Follow up was 95% complete and extended for a mean of 57 (30) months. Late mortality was 11.5%. Actuarial survival rates at 1, 3, and 5 years were 96%, 91%, and 86%, respectively.

CONCLUSIONS

Non-cardioplegic techniques are safe and effective in preserving the myocardium during CABG in patients with coronary artery disease and poor LV function, with low operative mortality and morbidity, and encouraging medium to long term survival rates.

Surgical treatments for heart failure

The surgical options for CHF are a part of a larger paradigm shift in management. Viable and effective surgical options other than cardiac transplant and ventricular assist devices clearly exist and are applicable to a large portion of patients with CHF. These surgical therapies are of acceptable risk before decompensated CHF develops. The rapidly evolving therapies for altering LV remodeling, which underlies CHF progression, are an exciting area that may be joined in the future by molecular advances in myoblast transfer and gene therapy. These therapies are the basis of the discipline of CHF surgery within cardiovascular surgery.

Surgical options for the treatment of heart failure

This article will examine the role of specific surgical interventions for congestive heart failure (CHF). The most definitive surgical option for severe end-stage heart failure is cardiac transplantation. In general, patients considered for heart transplant should have severe heart disease despite all other therapies with a high risk of death within 1 year. Noncardiac conditions that would by themselves shorten life expectancy or increase the risks of rejection, infection, or other fatal complication, should not be present. However, in light of the limited donor pool, complications associated with long-term immunosuppressive therapy, and the ever-increasing number of CHF patients, the role of cardiac transplantation for CHF will continue to be limited. The conduct of and evaluation for cardiac transplantation has been well described previously and therefore will not be evaluated in this review (1); however, there has been recent progress in the genetic modification of animal organs for potential use in transplantation (xenografts) (2). If these developments come to fruition, then cardiac transplantation/organ replacement may become a surgical option for a much greater number of CHF patients. One alternative approach to complete cardiac transplantation is the surgical placement of transformed cells into the diseased myocardium, briefly discussed under "Future Directions." This article will examine surgical options that are currently being used for CHF patients, surgical modalities that are currently under clinical evaluation, and finally, potential future therapies with respect to surgical options for heart failure.

Surgical alternatives to transplantation and assist devices in the treatment of heart failure

It is estimated that in the United States 30,000 patients with end-stage heart disease are eligible for heart transplantation, although less than 2500 are actually performed each year. As the population ages, several thousand other patients who are ineligible for cardiac transplantation will be left with limited options. Surgical strategies aimed at halting the progression of heart failure have therefore been devised. High-risk coronary artery bypass grafting can improve ejection fraction and alleviate heart failure symptoms in appropriately selected patients. Mitral valve repair and ventricular aneurysm resection/plication procedures may improve heart failure by decreasing the volume load on the left ventricle. Myoreduction operations (Batista operation) aim to improve the volume and wall stress relationship of the dilated left ventricle, but their clinical application has remained experimental.

Surgical management of heart failure

Surgical therapy for congestive heart failure can offer gratifying results in selected elderly patients. Several trials have shown a survival advantage for surgical revascularization compared with medical therapy in the treatment of ischemic cardiomyopathy. Aortic valve replacement is highly effective in treating elderly patients with heart failure caused by severe aortic stenosis, and stentless aortic valves seem to provide a survival advantage in elderly patients with low-gradient aortic stenosis. Mitral valve repair with or without coronary revascularization has been used successfully in patients with severe mitral regurgitation. Transplantation is a viable but rarely used option for elderly patients with congestive heart failure. Totally implantable ventricular assist devices are an exciting new option for elderly patients with congestive heart failure who are not heart transplantation candidates.

Predictors of operative risk for coronary bypass operations in patients with left ventricular dysfunction

OBJECTIVES

The prevalence of ventricular dysfunction in patients undergoing coronary operations, as well as the prevalence of other risk factors in these patients, has been increasing. We identified the predictors of mortality and morbidity in patients with ventricular dysfunction to permit more accurate evaluation of risk and to direct future strategies to improve outcomes.

METHODS

Demographic, intraoperative, and outcome data were collected prospectively on 20,614 patients undergoing isolated coronary operations at our institution from 1982-1997. Multivariable regression analyses were used to identify the independent predictors of mortality and low-output syndrome.

RESULTS

Moderate ventricular dysfunction (ejection fraction, 20%-40%) was noted in 4107 (19.9%) patients, and severe dysfunction (ejection fraction, <20%) was noted in 680 (3.3%) patients. Patients with worse ventricular function had an increasing prevalence of other risk factors with time. Mortality decreased between the 1982-1986 and 1987-1991 cohorts but did not decrease further. Low-output syndrome was less common in the 1992-1997 cohort than in previous years. The predictors of mortality were ventricular dysfunction, age, reoperation, year of operation, urgency, female sex, and left main stenosis. Low-output syndrome was predicted by ventricular dysfunction, reoperation, year of operation, female sex, urgency, extensive coronary disease, age, left main stenosis, and symptom class.

CONCLUSIONS

Despite the increasing prevalence and risk profile of patients with ventricular dysfunction, mortality rates and incidence of low-output syndrome declined with time. Patients with severe dysfunction were at greatest risk when facing reoperation or urgent operation. Earlier intervention and more aggressive preoperative optimization may improve outcomes in these high-risk patients.

Surgical alternatives in the treatment of heart failure

Heart failure continues to plague a large population worldwide, and its incidence is increasing annually as a result of an aging population. It is associated with lengthy hospital stays, multiple hospital readmissions, and decreased quality of life because of its clinical manifestations. Although cardiac transplantation has become the therapy of choice for patients with heart failure, scarcity of donor hearts and age limitations prohibit its widespread use. Despite major advances in medical management, researchers continue to explore alternative surgical therapies to help augment cardiac function. This article explores surgical interventions in the management of heart failure, many of which are still experimental or in clinical trials. Coronary artery bypass surgery, dynamic cardiomyoplasty, and partial left ventriculectomy for the management of heart failure are discussed in detail. Descriptions of each surgical procedure, special care needs, and clinical outcomes are presented. However, because readers are familiar with the coronary artery bypass procedure and postoperative patient care, the discussion will focus on issues related to coronary artery bypass grafting in the presence of ischemic cardiomyopathy.