To the Editor:
I would like to compliment Dr Eagle and colleagues on an excellent article regarding cardiovascular risk of patients with coronary artery disease undergoing noncardiac surgery, published recently in Circulation.1 I do take issue, however, with the general statement that coronary revascularization done before the planned procedure is effective in reducing the risk of postoperative myocardial infarction and/or death.
Although retrospective studies, including the CASS registry patients used in Dr Eagle’s study, have shown a low mortality rate after noncardiac surgical procedures in patients who have undergone coronary bypass surgery, I do not believe that percutaneous revascularization procedures have been shown to be similarly effective. Again, retrospective studies have been done, such as the one by Huber et al2 from Mayo Clinic, that have not clearly shown whether PTCA is also “protective”.
It has been my perception that many angioplasty procedures are being performed, especially now with the widespread use of stenting, on patients who have been found by intensive preoperative testing and screening to have obstructive coronary disease, with the belief that the risk of surgery will be reduced. The article by Eagle et al may unintentionally foster behavior that is possibly inappropriate by not making a more clear distinction between surgical and percutaneous revascularization.
- Copyright © 1998 by American Heart Association
As Dr Miller points out, the prophylactic application of coronary angiography and related procedures for the expressed purpose of lowering coronary risk for noncardiac surgery remains ill defined. There have been at least 3 nonrandomized trialsR1 R2 R3 that suggest, on average, that patients who have successfully undergone coronary angioplasty without untoward complications are at relatively low risk for cardiac events after noncardiac surgery. However, these studies had no comparison group, and it is impossible to gauge whether any protection was conferred as a result of the angioplasty. Contrariwise, the evidence that suggests that prior successful coronary artery bypass surgery reduces the cardiac risk of noncardiac surgery is somewhat more compelling,R4 but again no randomized trial is available with this specific question in mind. Since the management of patients with coronary heart disease with medical, interventional, and surgical treatments is rapidly evolving, it is difficult to know which strategy or strategies will be most effective for reducing perioperative complications without prospective studies.
Because of these uncertainties, the recently published guideline on the evaluation and management of the patient with cardiac disease undergoing noncardiac surgery indicated that the justification to perform coronary artery angioplasty or coronary bypass surgery in such patients should be identical to the indications for these procedures in general.R4 At this point, there is no compelling evidence that one should create special indications for these procedures in individuals just because they are being considered for noncardiac surgery. However, it certainly is true that the presentation for noncardiac surgery may represent the first opportunity to identify a patient in need of further therapy, and a noncardiac procedure may influence the timing surrounding a decision to perform coronary intervention or bypass surgery for appropriate indications.
It was not the intent of our article on the CASS databaseR5 to promote routine preoperative testing and indiscriminate coronary interventions in patients being considered for noncardiac surgery. In fact, the national guideline on this topic specifically argues for a very selected use of noninvasive testing and interventional procedures in subsets of patients where current evidence supports their value.
Huber KC, Evans MA, Bresnahan JF, Gibbons RJ, Holmes DR Jr. Outcome of noncardiac operations in patients with severe coronary artery disease successfully treated preoperatively with coronary angioplasty. Mayo Clin Proc. 1992;67:15–21.
Eagle KA, Brundage BH, Chaitman BR, Ewy GA, Fleischer LA, Hertzer NR, Leppo JA, Ryan T, Schlant RC, Spencer WH 3rd, Spittell JA Jr, Twiss RD, Ritchie JL, Cheitlin MD, Gardner TJ, Garson A Jr, Lewis RP, Gibbons RJ, O’Rourke RA, Ryan TJ. Guidelines for perioperative cardiovascular evaluation for noncardiac surgery: report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines: Committee on Perioperative Cardiovascular Evaluation for Noncardiac Surgery. Circulation. 1996;93:1278–1317.
Eagle KA, Rihal CS, Mickel MC, Holmes DR, Foster ER, Gersh BJ, for the CASS Investigators. Cardiac risk of noncardiac surgery: influence of coronary disease and type of surgery in 3368 operations. Circulation. 1997;96:1882–1887.