Coronary-Artery Revascularization Before Elective Major Vascular Sugery
McFalls EO, Ward HB, Moritz TE, et al. Coronary-artery revascularization before elective major vascular surgery. N Engl J Med. 2004;351:2861-3.
Cardiac risk stratification and treatment prior to non-cardiac surgery is a frequent reason for medical consultation, and yet the optimal approach to managing these patients remains controversial. National guidelines, based on expert opinion and inferred from published data, suggest that preoperative cardiac revascularization be reserved for patients with unstable coronary syndromes or for whom coronary artery bypass grad ing has been shown to improve mortality. Despite these recommendations, there remains considerable variability in clinical practice, which is compounded by a paucity of prospective randomized trials to validate one approach over another.
In this multicenter randomized controlled trial, McFalls et al. studied whether coronary artery revascularization prior to elective vascular surgery would reduce mortality among a cohort of patients with angiographically documented stable coronary artery disease. The investigators evaluated 5859 patients from 18 centers scheduled for abdominal aortic aneurysm or lower extremity vascular surgery. Patients felt to be at high risk for perioperative cardiac complications based on cardiology consultation, established clinical criteria, or the presence of ischemia on stress imaging studies were referred for coronary angiography. Of this cohort, 4669 (80%) were excluded due to subsequent determination of insufficient cardiac risk (28%), urgent need for vascular surgery (18%), severe comorbid illness (13%), patient preference (11%), or prior revascularization without new ischemia (11%). Of the 1190 patients who underwent angiography, 680 were excluded due to protocol criteria including: the absence of obstructive coronary artery disease (54%), coronary disease not amenable to revascularization (32%), led main artery stenosis ≥ 50% (8%), led ventricular ejection fraction <20% (2%), or severe aortic stenosis (AVA<1.0 cm2) (1%).
Of the 510 patients who remained, 252 were randomized to proceed with vascular surgery with optimal medical management, of which 9 crossed over due to the need for urgent cardiac revascularization. Two hundred fifty-eight patients were randomized to elective preoperative revascularization; 99 underwent CABG, 141 underwent PCI, and 18 were excluded due to need for urgent vascular surgery, patient preference, or in one case, stroke. Both groups were similar with respect to baseline clinical variables, including the incidence of previous myocardial infarction, congestive heart failure, diabetes mellitus, led ventricular ejection fraction, and 3vessel coronary artery disease. They were also similar in the use of perioperative betablockers (~ 85%), statins, and aspirin.
At 2.7 years after randomization, mortality was 22% in the revascularization group and 22% in the medical management group, the relative risk was 0.98 (95% CI 0.7-1.37; p=.92), which was not statistically significant. The median time from randomization to vascular surgery was 54 days in the revascularization group and 18 days in the medical management group not undergoing revascularization (p<.001). Although not designed to address short-term outcomes, there were no differences in the rates of early postoperative myocardial infarction, death, or hospital length of stay. It is also worth noting that 316 of the 510 patients who were ultimately randomized had undergone nuclear imaging studies, of which 226 (72%) had moderate to large reversible perfusion defects detected. These outcome data suggest that the presence of reversible perfusions defects is not in itself a reason for preoperative revascularization.
This well-designed study demonstrates that in the absence of unstable coronary syndromes, led main disease, severe aortic stenosis, or severely depressed led ventricular ejection fraction, there is no morbidity or mortality benefit to revascularization among patients with stable coronary artery disease prior to vascular surgery. Because vascular surgery is the highest risk category among non-cardiac procedures, it may be reasonable to extend these findings to lower risk surgeries as well, and in this sense this study is particularly relevant to consultative practice. While this study provides clear evidence on how to manage this cohort of patients, it remains unclear what the optimal strategy is to identify and manage those patients who were excluded from the trial. (DF)