Coronary Artery Bypass Grafting (CABG): Reassessing Efficacy, Safety, and Cost

David K. Cundiff

In This Article

Quality-of-Life Outcomes Comparing CABG and Medical Management of CAD

Peduzzi and colleagues[10] analyzed the VA Hospitals' CABG trial, looking at quality-of-life indices in 639 patients with questionnaire data at 1 year after randomization. About 60% of surgically treated patients were markedly improved or were free of angina at 1 year compared with only 16% in the medically treated group. Surgically treated patients also required significantly lower doses of nitrates and propranolol, had better exercise tolerance, and less sexual dysfunction than the medically treated patients. The clinical outcomes in the surgically treated patients improved as a function of graft patency within the first year after bypass.[10]

However, an interesting subset of 29 surgically treated patients with repeat angiograms showing no patent grafts at 1 year also had a highly statistically significant benefit compared with medically treated patients in terms of freedom from anginal pain (P < .01).[10] In this subset, dyspnea and use of nitrates and propranolol were also significantly reduced after CABG.[10] The authors speculated that this effect might have been due to a placebo effect or other unexplained effect of the surgery, causing the patients not to feel ischemic coronary pain as they had before.

Improvement in angina with no graft patency was reminiscent of early attempts at revascularization by Beck and Vineberg that produced little or no increase in myocardial blood supply yet were associated with 60% to 80% reduction in angina.[11] Severing the vagus nerve sensory fibers to the epicardium during the procedure might explain the symptomatic improvement with CABG despite the absence of patent grafts. Another possible reason for this paradox is greater subsequent lifestyle changes (diet, exercise, etc.) after CABG compared with medical therapy.

Rogers and colleagues[5] reported on the quality-of-life indices for the Coronary Artery Surgery Study (CASS) patients randomized to initial medical vs surgical treatment. At 1 year and at 5 years, the patients randomized to CABG had statistically significantly less angina. However, at 10 years, no statistically significant difference remained between the groups in frequency of angina. Surgically treated patients also needed less beta-blockers and nitrates for pain control at 1 and 5 years but not at 10 years. The authors reported no significant differences in recreation status, employment status, frequency of congestive heart failure, use of other medications, or hospitalization frequency. They thought that part of the lack of durability of freedom from angina in patients randomized to CABG was that 37% of patients randomized to medical treatment had received CABG by the tenth year.[5] They did not report the frequency of angina in surgically treated CASS patients who had all grafts closed at follow-up catheterization.


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