Chapter 24: Coronary Artery Reoperations

INTRODUCTION

Coronary artery reoperations are more complicated than primary operations. Patients undergoing reoperations have distinct, more dangerous pathologies; reoperations are technically more difficult to perform; and the risks are greater.^1-12 Vein graft atherosclerosis, present in most reoperative candidates, is a unique and dangerous lesion. Reoperative candidates commonly have severe and diffuse native-vessel distal coronary artery disease (CAD), a problem that has had the time to develop only because these patients did not die from their original proximal coronary artery lesions. Aortic and noncardiac atherosclerosis are also often far advanced in many reoperative candidates. Some technical hazards, including the presence of patent arterial grafts and sternal reentry, are unique to reoperations, and others, such as lack of bypass conduits and difficult coronary artery exposure, are common.

INCIDENCE OF REOPERATION

After a primary bypass operation, the likelihood of a patient undergoing a reoperation depends on patient-related variables, primary operation-related variables, adherence to strict medical control of risk factors for disease progression after bypass surgery, the possibility of alternative treatments, physician opinion about the feasibility of reoperation, and time. Studies from the Cleveland Clinic demonstrated a cumulative incidence of reoperation of 3% by 5 years, 10% by 10 years, and 25% by 20 postoperative years¹³ (Fig. 24-1). Factors associated statistically with an increased likelihood of reoperation have been variables predicting a favorable long-term survival (eg, young age, normal left ventricular function [LVF], and single- or double-vessel disease), variables designating an imperfect primary operation (eg, no internal thoracic artery [ITA] graft and incomplete revascularization), and symptom status (eg, class III or IV symptoms at primary operation). Young age at primary operation and incomplete revascularization are also markers of a severe atherogenic diathesis.

Over recent decades the proportion of isolated coronary artery operations that are reoperations has decreased. In 1990, about 37% of coronary artery revascularization operations were reoperative interventions, whereas in 2002 this figure was 30%¹⁴ (Fig. 24-2). Compared to that year, a much more dramatic decrease in reoperative coronary bypass surgery occurred during the most recent decade, with reoperative procedures representing only 4.6% of all isolated coronary bypass operations. This decrease is related in part to the more aggressive use of coronary artery interventions for patients with previous bypass surgery and probably to more effective risk factor control. Also, surgery has changed in directions that will decrease the rate of reoperation. Use of the left internal thoracic artery (LITA) to graft the left anterior descending (LAD) coronary artery decreases ...