ORLANDO – Virtually no patients with type 2 diabetes and documented coronary artery disease and coronary ischemia benefit from immediate coronary revascularization, as long as they receive intensive medical management, based on the outcomes of more than 1,000 patients who were randomized to the deferred revascularization arm of the BARI 2D trial.
The only possible exception to this approach are the rare patients who initially present with severe or unstable angina and proximal left anterior descending (LAD) artery disease, a small group accounting for just 2% of these patients, Dr. Ronald J. Krone said at the annual scientific sessions of the American Heart Association. Even in this small subgroup with the worst chance of avoiding revascularization, eventual coronary bypass surgery or percutaneous coronary intervention (PCI) is not an absolute. Among the 21 patients with this initial presentation at study entry (of the total 1,192 who were randomized to the deferred revascularization arm), 50% continued to avoid revascularization 6 months later, and 29% had still not undergone revascularization 5 years after the study began, said Dr. Krone, an interventional cardiologist and professor of medicine at Washington University, St. Louis.
Dr. Ronald J. Krone
"What it comes down to is that there is no group you can identify up front" that unequivocally needs immediate revascularization," Dr. Krone said in an interview. "We could not identify patients who will need revascularization at a high enough rate to warrant initial revascularization, with the possible exception" of the small proximal LAD and severe angina subgroup. "Even in the worst patients, you can intervene later. We used to be afraid that if we didn’t [revascularize these patients] they would drop dead or have a big myocardial infarction, but that didn’t happen. These results give us confidence that you don’t need to intervene on every tight lesion."
Today, a physician or surgeon can’t say "’I have to revascularize, because it’s the best I can do’" for these patients. Instead, the onus is to intensively treat these patients medically, especially patients with diabetes, Dr. Krone said. This strategy includes optimal control of hypertension, lipids, glycemia, and intensive lifestyle intervention with exercise, diet, and smoking cessation.
The analysis he presented focused on patients enrolled in the BARI 2D (Bypass Angioplasty Revascularization Investigation in Type 2 Diabetes), which randomized a total of 2,368 patients with diabetes and documented coronary ischemia and stenosis suitable for an elective intervention. The researchers put all these patients on an intensive medical management regimen, and also randomized them to either immediate or deferred revascularization. The study’s primary results showed absolutely identical 5-year outcomes in the two groups, with a mortality rate of 12% in each arm of the study, and a combined rate of death, MI, or stroke of 23% in the immediate revascularization patients and 24% in those with deferred intervention (N. Engl. J. Med. 2009;360:2503-15).
Among the 1,192 patients in the deferred subgroup, 13% required PCI or bypass surgery after 6 months, and 40% needed revascularization after 5 years of follow-up. Within the group who eventually had revascularization, 47% required it for worsening angina, 23% because of an acute coronary syndrome event, 18% for worsening ischemia, 6% for progression of their coronary disease, and the remaining 6% for another reason. The current analysis aimed to determine whether "we can identify patients with such a high likelihood of needing revascularization that it need not be deferred," Dr. Krone said.
The average age of the patients in the deferred revascularization group was 62 years; 30% were women, 28% were on insulin treatment, 17% had a left ventricular ejection fraction below 50%, and 13% had proximal LAD coronary disease. Their average duration of type 2 diabetes was 11 years.
A multivariate analysis that controlled for age, sex, race, and nationality identified five factors that were linked with a significantly increased rate of revascularization after 6 months: class III or IV stable angina, unstable angina, a systolic blood pressure of 100 mm Hg or less, a blood triglyceride level of 100 mg/dL or less, and proximal LAD disease. These factors were linked with anywhere from a 3.8-fold increased rate of revascularization (in patients with systolic hypotension, compared with patients with a systolic pressure greater than 100 mm Hg) to a 75% increased rate (in patients with proximal LAD disease, compared with those without LAD disease). However, none of these increased rates appeared to justify performing routine, upfront revascularization.
The 5-year multivariate analysis produced similar results. It identified nine baseline factors that each significantly linked with a significantly increased rate of revascularization during 5-year follow-up: class I or II stable angina, class III or IV stable angina, unstable angina, systolic blood pressure of 101-120 mm Hg, a systolic pressure of 100 mm HG or less, a blood triglyceride level of 100 mg/dL or greater, proximal LAD disease, having two diseased coronary regions, or having three diseased coronary regions. The increased rates associated with these features ranged from a 90% increased revascularization rate (in patients with class III or IV stable angina, compared with patients without angina), to a 28% increased revascularization rate (in patients with class I or II stable angina at baseline). Again, none of these increased rates appeared to justify uniform, upfront revascularization, Dr. Krone said.