Greg C. Larsen

Predictors and outcomes of a perioperative myocardial infarction following elective vascular surgery in patients with documented coronary artery disease: results of the CARP trial.

AIMS The predictors and outcomes of patients with a peri-operative elevation in cardiac troponin I above the 99th percentile of normal following an elective vascular operation have not been studied in a homogeneous cohort with documented coronary artery disease. METHODS AND RESULTS The Coronary Artery Revascularization Prophylaxis (CARP) trial was a randomized trial that tested the benefit of coronary artery revascularization prior to vascular surgery. Among 377 randomized patients, core lab samples for peak cardiac troponin I concentrations were monitored following the vascular operation and the blinded results were correlated with outcomes. A peri-operative myocardial infarction (MI), defined by an increase in cardiac troponin I greater than the 99th percentile reference (> or =0.1 microg/L), occurred in 100 patients (26.5%) and the incidence was not dissimilar in patients with and without pre-operative coronary revascularization (24.2 vs. 28.6%; P = 0.32). By logistic regression analysis, predictors of MI (odds risk; 95%CI; P-value) were age >70 (1.84; 1.14-2.98; P = 0.01), abdominal aortic surgery (1.82; 1.09-3.03; P = 0.02), diabetes (1.86; 1.11-3.11; P = 0.02), angina (1.67; 1.03-2.64; P = 0.04), and baseline STT abnormalities (1.62; 1.00-2.6; P = 0.05). At 2.5 years post-surgery, the probability of survival in patients with and without the MI was 0.73 and 0.84, respectively (P = 0.03, log-rank test). Using a Cox proportional hazards regression analysis, a peri-operative MI in diabetic patients was a strong predictor of long-term mortality (hazards ratio: 2.43; 95% CI: 1.31-4.48; P < 0.01). CONCLUSION Among patients with coronary artery disease who undergo vascular surgery, a peri-operative elevation in cardiac troponin levels is common and in combination with diabetes, is a strong predictor of long-term mortality. These data support the utility of cardiac troponins as a means of stratifying high-risk patients following vascular operations.

Perioperative Complications After Vascular Surgery Are Predicted by the Revised Cardiac Risk Index But Are Not Reduced in High-Risk Subsets With Preoperative Revascularization

Background—The Revised Cardiac Risk Index (RCRI) is useful for risk stratifying patients before noncardiac operations. Among patients with documented coronary artery disease who undergo vascular surgery, it is unclear whether preoperative revascularization reduces postoperative cardiac complications in high-risk subsets defined by the RCRI. Methods and Results—The Coronary Artery Revascularization Prophylaxis Trial was a randomized, controlled trial that tested the long-term benefit of a preoperative coronary artery revascularization before elective vascular surgery. Using preoperative baseline characteristics to determine the RCRI, we tested the benefit of preoperative revascularization on death and nonfatal myocardial infarction in patients with multiple risks. Among 462 patients undergoing vascular surgery, there were 72 complications (15.6%) within 30 days postsurgery, including 15 deaths (3.2%) and 57 nonfatal myocardial infarctions (12.3%). The postoperative risk of death and nonfatal myocardial infarction after surgery increased according to the RCRI (odds ratio, 1.73; 95% CI, 1.26 to 2.38; P<0.001), with a rate of 1.6% in patients with no risk that increased to 23.4% in patients with ≥3 risks. Preoperative revascularization had no influence on the incidence of complications in any risk subset (odds ratio, 0.86; 95% CI, 0.50 to 1.49; P=0.60). Among those individuals with ≥2 risks who also demonstrated ischemia on a preoperative stress-imaging test (N=146), the incidence of events was 23% in patients with and without preoperative revascularization (P=0.95). Conclusions—The risk of death and nonfatal myocardial infarction is accurately predicted by the RCRI in patients undergoing vascular surgery but is not reduced in any high-risk subset of the RCRI with preoperative coronary artery revascularization.

Preoperative coronary artery revascularization and long-term outcomes following abdominal aortic vascular surgery in patients with abnormal myocardial perfusion scans: a subgroup analysis of the coronary artery revascularization prophylaxis trial.

Background: Abdominal aortic operations have the highest perioperative cardiac risk. To test the impact of preoperative coronary artery revascularization (PR) in this high‐risk subset, a post hoc analysis was performed in patients undergoing aortic surgery within the Coronary Artery Revascularization Prophylaxis (CARP) trial. Methods: The study cohort was a subset of 109 CARP patients with myocardial ischemia on nuclear imaging randomized to a strategy of PR (N = 52) or no PR (N = 57) before their scheduled abdominal aortic vascular operation. The clinical indications for vascular surgery were an expanding aneurysm (N = 62) or severe claudication (N = 47). The composite end‐point of death and nonfatal myocardial infarction (MI) was determined by an intention‐to‐treat analysis following randomization. Results: The median time (Interquartiles) from randomization to vascular surgery was 56 (40, 81) days in patients assigned to PR and 19 (10, 43) days in patients assigned to no PR (P < 0.001). At 2.7 years following randomization, the probability of remaining free of death and nonfatal MI was 0.65 with PR and 0.55 with no PR [unadjusted P = 0.08, odds ratio = 1.67, 95% confidence interval (0.93, 2.99)]. Using a Cox proportional hazard model, predictors of the composite of death and nonfatal MI (odds ratio; 95% confidence interval) were no PR (1.90; 1.06–3.43; P = 0.03) and anterior ischemia on preoperative imaging (1.79; 0.99–3.23; P = 0.07). Conclusions: In patients with an abnormal cardiac imaging before abdominal aortic vascular surgery, PR was associated with a reduced risk of death and nonfatal MI while anterior ischemia was an identifier of poor outcome independent of the revascularization status.

Culprit Coronary Lesions Requiring Percutaneous Coronary Intervention After Vascular Surgery Often Arise From In-Stent Restenosis of Bare Metal Stents

BACKGROUND The natural history of coronary artery disease (CAD) after vascular surgery is poorly defined. The aim of this study was to determine the temporal change of coronary artery lesions requiring revascularization with a percutaneous coronary intervention (PCI) after elective vascular surgery and to determine the utility of preoperative biomarkers on predicting those patients at risk for new coronary lesions. METHODS The Coronary Artery Revascularization Prophylaxis Trial tested the long-term survival benefit of coronary artery revascularization before elective vascular surgery. Among randomized patients who subsequently required PCI after surgery, the stenosis of the culprit lesion from the follow-up angiogram was compared with the preoperative vessel stenosis at the identical site on the baseline angiogram. RESULTS A total of 30 patients underwent PCI for progressive symptoms at a median of 11.5 (interquartiles: 4.5-18.5) months postsurgery. Of 30 patients, 16 (53%) had nonobstructive CAD preoperatively (group 1) with a stenosis that increased from 17 +/- 6% to 91 +/- 2% (P < 0.01) and 14 (47%) had severe CAD at the culprit site preoperatively (group 2), with a stenosis that increased 89 +/- 2% (P = 0.15). The only biomarker that was an identifier of early coronary artery lesion formation in group 1 compared with group 2 patients was a higher baseline homocysteine level (14.6 +/- 1.4 vs. 10.6 +/- 0.7 mg/dL; P = 0.02). CONCLUSIONS Culprit coronary artery lesions requiring PCI after an elective vascular operation often arise from in-stent restenosis. Therapies that either stabilize existing plaques or prevent restenosis, particularly among patients with elevated homocysteine levels, have the greatest promise for improving postoperative outcomes.