Cardiovascular disease accounts for one million deaths and is the major cause of mortality among Americans. Although a reduction in the prevalence of coronary artery disease has been noted over the past 2 decades, the increasing age of the population will result in more patients developing coronary artery disease. the number of Americans older than 65 years is approximately 25 million and over the next 50 years is expected to exceed 65 million.
Coronary artery disease accounts for the majority of perioperative morbid events in patients undergoing vascular surgery and is the cause of death in at least half of all patients who do not survive. the incidence of cardiac complications is highly dependent upon the nature of the operation, the population at risk and the expertise of the anesthesiologist and surgeon. Perioperative cardiac morbidity occurs in 13-19% of high risk patients and leads to death in approximately 1-10%. This is much higher than might be expected in general medical patients without cardiac disease, where the incidence of perioperative myocardial infarction is between 0.13 and 0.7%.
A new prospective controlled clinical trial is needed to address the question of whether prophylactic coronary artery revascularization is protective in patients scheduled for elective vascular surgery. because of the large number of peripheral vascular surgeries being performed in the VA Medical Centers, the Department of Veterans Affairs is an ideal system in which to conduct this study and the Greater VA Medical Center at West Los Angeles has been chosen to be one of these sites and we have just begun this study this month.
The primary hypothesis of this study is that prophylactic coronary artery revascularization in high risk patients scheduled for elective vascular surgery reduces long-term risk of mortality. Secondary hypotheses include that prophylactic coronary artery revascularization in high risk patients scheduled for elective vascular surgery reduces long-term risk of myocardial infarction and is cost-effective and improves the quality of life in those patients treated.
All patients in need of elective vascular surgery will be considered candidates for this study. The patient then is screened to have at least 2 of the following cardiac risk factors: prior myocardial infarction, history of angina, pathologic q-waves, congestive heart failure diagnosed by a cardiologist, ventricular ectopy (requiring treatment). Also, those who have a positive stress imaging test or other clinical risk factor for which coronary angiography is indicated are also candidates. Exclusion criteria will include emergent surgery, severe chronic medical illnesses, such as a FEV 1 <1.0 sec., serum creatinine >3.5 mg/dl, metastatic cancer, severe dementia, severe liver disease, stroke within 3 months of screening, unstable angina or prior coronary artery revascularization.
Coronary angiography will be performed by standard techniques and the presence of coronary stenosis will be estimated based on multiple views. Left ventricular ejection fraction estimates will be made by ventricular angiography, radilnuclide angiography with multiple gating (MUGA) with 2D ECHO. Those with the following catheterization results will be excluded: non-obstructive coronary arteries (stenosis less than 70%), LVEF < 20%, aortic valve area < 1cm2, left main stenosis > 50% and coronary arteries not amenable to revascularization. All others will be randomized. The patients who are randomized to the coronary revascularization arm and the cardiologist and the cardiac surgeon will determine the optimum treatment plan for that patient. The patient randomized to the medical treatment arm will have their medications maximized by the cardiologist. The vascular operation will then occur within 3 months of randomization and the patients will have cardiac enzymes and EKGs performed up to 4 days following the procedure.
Outcome measures will be mortality, myocardial infarction, cost-effectiveness as assessed by hospital charges and quality of life issues assessed by surveys (SF-36 and Seattle Angina Questionnaire). Randomization will take place over 3 years and follow-up until 5 years. It is expected that those patients who had coronary revascularization will demonstrate better outcomes by lower mortality, lower myocardial infarction rates, less re-hospitalizations resulting in lower costs overall and a better quality of life with less angina.