BALTIMORE — The jury remains out on the safety and efficacy of coronary revascularization for very high-risk patients before they have major vascular surgery.
A pilot study that randomized 101 adult patients to revascularization or medical therapy before major vascular surgery failed to show (and was underpowered to show) a significant overall outcome difference between these two options, Dr. Olaf Schouten said at the Vascular Annual Meeting. A definitive test of the idea that selective revascularization before vascular surgery yields better outcomes would need to screen about 9,000 patients and find at least 600 to enroll in the randomized trial, said Dr. Schouten, a vascular surgeon at Erasmus Medical Center, Rotterdam, the Netherlands. It's unclear whether such a large and expensive study will ever occur.
However, the study did raise questions about the best sequence of treatments in patients with advanced coronary disease who also need major vascular surgery, such as repair of an abdominal aortic aneurysm. That's because the results of a subgroup analysis showed that among the patients who survived the first 30 days after vascular surgery, the mortality rate among those who first had coronary revascularization was 46% less than those who did not have revascularization, a statistically significant difference. This finding suggests that the long-term benefit of performing revascularization first is undercut by an acute risk, probably stent thrombosis, Dr. Schouten said in an interview. But he stressed that this subgroup analysis from limited data does not support initial revascularization; it just highlights the complex interplay between the benefits and adverse effects of initial revascularization in these patients.
In the study, 32 of the 49 revascularization patients underwent a percutaneous coronary intervention and coronary stenting; 30 of these 32 patients received drug-eluting stents. The other 17 patients in this subgroup had coronary bypass surgery. The average interval between revascularization and vascular surgery was about 30 days, and patients who were on dual antiplatelet therapy continued the regimen during vascular surgery.
Another study, the Dutch Echocardiographic Cardiac Risk Evaluation Applying Stress Echo (DECREASE)-V pilot study, was done during 2000–2005 at six hospitals in six countries (J. Am. Coll. Cardiol. 2007;49:1763–9). The investigators screened 1,880 consecutive patients scheduled to undergo elective, open reconstruction of their abdominal aortic or infrainguinal arteries.
The primary end point was all-cause death and nonfatal MI during 30 days after vascular surgery. The rates were 43% in the revascularized patients and 33% in those managed medically, a difference that was not significant. At 1 year, the rate of death or MI was 49% and 44%, respectively, also a nonsignificant difference. No patient in the medical therapy group had revascularization during the first year.
The study focused on extremely high-risk patients because they are the most likely to benefit from coronary revascularization before vascular surgery, Dr. Schouten said. Patients were screened for risk factors, including age over 70, angina, prior MI, heart failure, diabetes, and renal dysfunction. Patients with at least three risk factors underwent cardiac stress testing. All 101 patients who showed extensive, stress-induced cardiac ischemia were enrolled in the trial. About a quarter of the patients had two-vessel coronary disease; the remainder had triple-vessel disease.
All patients were maintained on β-blockers, either continuing their preexisting regimen or starting on bisoprolol (Zebeta). The dosage for all patients was adjusted to achieve a resting heart rate of 60–65 beats per minute. Fifty-two patients were managed medically only, and 49 underwent revascularization; all then underwent scheduled vascular surgery. Two patients, both of whom had coronary bypass surgery, died from a ruptured aneurysm before their vascular surgery occurred.