Mortality, cardiac mortality, and myocardial infarction in patients with multivessel CAD and ischemia treated with either PTCA or CABG
Appraised by: Deb Bynum, MD
November 10, 1997
Clinical Bottom Lines:
1) In a randomized trial comparing CABG vs PTCA as the initial treatment in patients with multivessel CAD and severe angina or ischemia, there was no significant difference between the two treatment groups in cumulative total mortality after 5.4 years of follow-up.
2) The cumulative cardiac mortality rate at 5 years was 4.9% in the CABG group vs 8.0% in the PTCA (RR 1.55, p=.022).
3) There was no significant difference in the cumulative rate of the composite endpoint of cardiac mortality or MI at 5 years (17.5% in the CABG group, 20.2% PTCA group, RR1.15, p=.23).
4) There was an increased rate of MI’s during the index hospitalization and after the initial procedure in the CABG group (41 Qwave MI’s) compared to the PTCA group (19 Qwave MI’s), p=.004. 12 of the 19 MI’s in the PTCA group occured after CABG for failed PTCA.
5) After the index hospitalization discharge, the MI rate was greater in the PTCA group than in the CABG group (122 vs 75, p<.001).
6) RR for cardiac mortality after MI was 5.9 (p<.001).
7) The 5 year cardiac mortality rate was overall higher in patients with a history of treated diabetes compared to patients with no prior diagnosis of diabetes. Within this subgroup of patients with diabetes, there was a significant discrepancy in the 5 year cardiac mortality between the PTCA group (23.4%) vs the CABG group (8.2%). Cumulative 5 year cardiac mortality rates or MI’s were not significantly different between treatment groups in the nondiabetic population (4.2% mortality for CABG vs 4.6% cardiac mortality for PTCA).
The Evidence: Randomized trial of CABG vs PTCA as the initial treatment strategy in patients with multivessel CAD and severe angina or ischemia. Patients with left main disease or prior revascularization were excluded. Data analyzed by intention to treat.
| Total Population | Patients without treated Diabetes | |||||
| CABG | PTCA | RR(CI) | CABG | PTCA | RR(CI) | |
| 5 Year Cardiac Mortality: | ||||||
| Overall: | 4.9% | 8.0% | 1.55(1.07-2.23) | 4.2% | 4.6% | |
| No DM | 4.2% | 4.6% | ||||
| DM | 8.2% | 23.4% | ||||
| 5 Year Cardiac Mortality or MI: | ||||||
| Overall | 17.5% | 20.2% | 1.15(.93-1.42) | 16.9% | 16.9% | |
| No DM | 16.0% | 16.9% | ||||
| DM | 23.7% | 35.0% |
Comments:
1) The primary endpoint of the BARI trial was overall mortality -- there was no difference in overall mortality in patients undergoing PTCA vs CABG for treatment of multivessel CAD with significant ischemia. The main results discussed in the paper however relate to secondary endpoints -- cardiac mortality and MI.
2) There was a significant difference observed in how diabetic patients do compared to nondiabetic patients and this study supports prior evidence that patients with diabetes and multivessel disease benefit more from CABG than PTCA (and benefit more from CABG than nondiabetic pateients). The ARR in patients with diabetes treated with CABG instead of PTCA was 15.2% decrease in mortality for a NNT of 6.6 (to prevent one cardiac death).
3) Beware the subgroup analysis -- this study was not designed to determine how patients with diabetes do with PTCA or CABG compared to patients without diabetes.
4) Potential for underestimation of procedure related non-Qwave MI rate because cardiac enzymes were not sampled in the initial 96 hrs after the procedure.
Chaitman, B.R. et al. Myocardial Infarction and Cardiac Mortality in the Bypass Angioplasty Revascularization Investigation (BARI) Randomized Trial.Circulation. 1997; 96:2162-2170.