Role of Coronary Collaterals in Off-Pump and On-Pump Coronary Bypass Surgery

Abstract

Background-Collaterals limit infarct size, preserve viability, and reduce mortality in patients with acute myocardial infarction. In patients with stable coronary disease, collaterals are associated with less angina and ischemia during angioplasty and fewer ischemic events during follow-up. The role of collaterals has not been studied in patients undergoing off-pump or on-pump bypass surgery. Methods and Results-The population consisted of the 281 patients randomized to off-pump or on-pump CABG in the Octopus Study. Collaterals were defined on the baseline angiogram with the Rentrop score and were present in 49% and 51% of the patients in the off-pump and on-pump group, respectively. Perioperative myocardial infarction was defined by a creatine kinase-MB to CK ratio Ͼ10% and occurred in 18.2% in the off-pump group and 32.5% in the on-pump group. The unadjusted OR of perioperative myocardial infarction in the presence of collaterals was 0.31 (95% CI 0.17 to 0.84) in the off-pump group and 1.06 (95% CI 0.29 to 3.85) in the on-pump group After adjustment for age, gender, hypertension, hypercholesterolemia, diabetes, multivessel disease, ventricular dysfunction, incomplete revascularization, and ischemic time, the OR was 0.34 (95% CI 0.14 to 0.84) in the off-pump group and 1.28 (95% CI 0.30 to 5.40) in the on-pump group, respectively. Kaplan-Meier estimates of event-free survival at 1 year were 87% in patients with and 69% in those without collaterals after off-pump CABG. These estimates were 66% and 63%, respectively, after on-pump CABG. Conclusions-Collaterals protect against perioperative myocardial infarction during off-pump surgery but not during on-pump surgery and are associated with a better 1-year event-free survival.

Historical Aspects and Relevance of the Human Coronary Collateral Circulation

“…The debate was in part related to different states of disease examined (acute versus chronic CAD, varying severity of CAD), to the imprecise and variable definition of the term “prognosis”, and to methodological issues such as the rare occurrence of study endpoints, the insufficient duration of follow-up and the blunt instrument employed to measure collateral supply. For example, two recent studies have documented a reduction in non-fatal cardiovascular events among patients with versus those without angiographic coronary collaterals in chronic stable CAD [21, 22]. On the other hand, data from the same group have indicated an unfavourable prognosis in the presence of angiographic collaterals among patients with more severe chronic CAD [23].…”

“…The majority of studies on the prognostic influence of collaterals in chronic CAD have employed angiographic grading for collateral assessment. It was not until 2004 that the prognostic impact of coronary collaterals as assessed by angiographic collateral grading regained interest [21]. In 281 patients randomized to off-pump or on-pump coronary bypass surgery, Nathoe et al .…”

“…In 281 patients randomized to off-pump or on-pump coronary bypass surgery, Nathoe et al . found angiographic collaterals in close to 50% [21]. Cumulative 1-year event-free survival rates were 87% in patients with and 69% in those without collaterals after off-pump bypass surgery, respectively (p=0.01); the respective figures were 66% and 63%, respectively (p=0.79), following on-pump surgery [21].…”

“…found angiographic collaterals in close to 50% [21]. Cumulative 1-year event-free survival rates were 87% in patients with and 69% in those without collaterals after off-pump bypass surgery, respectively (p=0.01); the respective figures were 66% and 63%, respectively (p=0.79), following on-pump surgery [21]. The protective effect of collaterals in the off-pump group was related to fewer peri-operative myocardial infarcts than in the on-pump group.…”

Plasma Chemokine Levels Are Associated with the Presence and Extent of Angiographic Coronary Collaterals in Chronic Ischemic Heart Disease

“…A major compensatory mechanism in patients with chronic IHD is the recruitment of coronary collaterals, a form of vascular remodeling that can be quantified angiographically. Presence of spontaneously visible coronary collaterals is associated with better outcomes in a broad spectrum of patients with varying degrees of IHD burden [2], including patients with acute myocardial infarction [3], [4], [5], [6], [7], [8], and patients with chronic IHD undergoing percutaneous [9], [10] and surgical [11], [12], [13] coronary revascularization. Recruitable coronary collaterals have also been assessed in patients with chronic IHD and are similarly associated with improved clinical outcomes [14].…”