SAN FRANCISCO — New guidelines for perioperative evaluation and management of cardiac patients undergoing noncardiac surgery are expected to be released in the spring, and they are likely to shift the emphasis from preoperative risk stratification to optimizing medical therapy in order to reduce perioperative complications, Dr. Gabriel Gregoratos said at a meeting sponsored by the California chapter of the American College of Cardiology.
New data have come along to challenge the current guidelines, published by the college and the American Heart Association in 2002, regarding preoperative cardiac testing, preoperative revascularization procedures, and the use of perioperative β-blockers in low-risk patients, said Dr. Gregoratos, professor of medicine at the University of California, San Francisco.
The current guidelines call for those at intermediate risk for perioperative cardiac events to undergo noninvasive assessment of the severity of cardiac ischemia, proceeding to cardiac surgery if the severity is significant. Predictors of intermediate risk in patients with coronary disease include mild angina, a prior MI, compensated or prior heart failure, or diabetes mellitus. Preoperative noninvasive testing also is appropriate, the guidelines say, in patients with poor functional capacity or who are undergoing a high-risk surgery.
Several recent studies, however, suggest that patients who underwent preoperative noninvasive testing to evaluate myocardial ischemia fared worse than those who were not tested, Dr. Gregoratos said at the meeting, also sponsored by the university. One randomized study of 1,476 intermediate-risk patients undergoing vascular surgery found a 2.3% rate of cardiac death or nonfatal MI within 30 days in tested patients, compared with a 1.8% rate in nontested patients (J. Am. Coll. Cardiol. 2006;48:964–9).
The difference between groups was not statistically significant, but “we have to consider why this is happening,” he said. “I would suggest that when we submit patients to preoperative testing and then some of them go to revascularization, we are not giving them any benefit, and we may be doing them harm.”
Preoperative testing delayed the noncardiac surgery by 3 weeks.
Other data have shown equivocal results on the potential benefit of preoperative coronary artery bypass grafting or percutaneous coronary intervention when performed simply to reduce the risk of complications from noncardiac surgery.
A major randomized study of 510 cardiac patients undergoing elective vascular surgery found no difference in survival at 6 years in those who did or didn't get preoperative revascularization to reduce perioperative risk (N. Engl. J. Med. 2004;351:2795–804). A trend suggested higher mortality in the first year after surgery for patients who were revascularized.
The guidelines already state that the decision to revascularize patients in preparation for noncardiac surgery is appropriate only in a very small subgroup of very high-risk patients. “I suspect that the revised guideline will be even stronger than this statement,” Dr. Gregoratos said.
The reductions in perioperative MI or death in cardiac patients given β-blockers around noncardiac surgery seem to benefit mainly patients at high risk for an ischemic event, he said. For patients with a Revised Cardiac Risk Index score of 0, 1 of every 208 patients given perioperative β-blockers will be harmed, a large retrospective study suggests (N. Engl. J. Med. 2005;353:349–61).
In addition, simply giving β-blockers is not enough to benefit intermediate-risk patients. Tight heart rate control is the key. “Patients have to be physiologically β-blocked,” he emphasized.