CABG led to less angina, reintervention, and medication than did PTCA, but mortality did not differ
ACP J Club. 1996 Mar-April;124:42. doi:10.7326/ACPJC-1996-124-2-042
Related Content in this Issue
• Companion Abstract and Commentary: Review: CABG leads to less angina and less reintervention than PTCA, but mortality and subsequent MI are the same
Related Content in the Archives
• Correction: CABG led to less angina, reintervention, and medication than did PTCA, but mortality did not differ
CABRI Trial Participants. First-year results of CABRI (Coronary Angioplasty versus Bypass Revascularisation Investigation). Lancet. 1995 Nov 4;346:1179-84. [PubMed ID: 7475656]
To compare the efficacy of revascularization by coronary artery bypass grafting (CABG) with that by percutaneous transluminal coronary angioplasty (PTCA) in patients with symptomatic multivessel coronary disease.
Randomized controlled trial with 1-year follow-up (originally designed with power to assess differences at 5 y).
26 European cardiac centers.
1054 patients (4.6% of all revascularizations during the recruitment period) < 76 years of age (mean age 60 y, 78% men) who needed revascularization and had symptomatic multivessel coronary disease, a left-ventricular ejection fraction > 0.35, typical or unstable angina pectoris, a 50% reduction of luminal diameter in ≥ 2 major epicardial vessels, ≥ 1 lesion suitable for PTCA, and a diameter ≥ 2 mm in the vessel distal to the lesion. Exclusion criteria were overt cardiac failure, acute myocardial infarction within 10 days, recent cerebrovascular event, previous CABG or PTCA, severe concomitant cardiac illness, or any condition that affected short-term survival. 4 patients were lost to follow-up.
513 patients were allocated to CABG and 541 patients to PTCA. Aspirin was the only drug stipulated to be used with the interventions.
Main Outcome Measures
Mortality, symptom status, reintervention, and medication use.
Analysis was by intention to treat. 93% of patients allocated to CABG and 96% allocated to PTCA had the assigned procedure. After 1 year, 14 patients allocated to CABG and 21 allocated to PTCA had died (P = 0.29) (Table). CABG led to fewer patients with clinically significant angina at 1 year than did PTCA (P = 0.012) (Table). Although this trend was true for both sexes, the difference was significant only in women. 94% of patients allocated to CABG compared with 66% of those allocated to PTCA reached 1 year with a single revascularization procedure (P < 0.001). During the first year of follow-up, patients in the CABG group used antianginal drugs less than did patients in the PTCA group (P < 0.001).
After 1 year, coronary artery bypass grafting led to fewer cases of clinically significant angina, fewer reinterventions, and less use of antianginal drugs than did percutaneous transluminal coronary angioplasty in patients with symptomatic multivessel coronary disease. Mortality did not differ.
Sources of funding: CR Bard (USCI) Inc; World Health Organization; European Society of Cardiology; Participating Centers.
For article reprint: Dr. A.F. Rickards, Royal Brompton Hospital, London SW3 6NP, England, UK. FAX 44-207-351-8473.
Table. Coronary artery bypass grafting (CABG) vs percutaneous transluminal cornary angioplasty (PTCA) in symptomatic multivessel coronary disease*
|Outcomes at 1 y||CABG||PTCA||RRR (95% CI)||NNT (CI)|
|Mortality||2.7%||3.9%||30% (-35 to 63)||Not significant|
|Angina||10%||14%||28% (0.3 to 48)||24 (12 to 2463)|
*Abbreviations defined in Glossary; RRR, NNT, and CI calculated from data in article.
CABG and PTCA are effective, frequently done revascularization techniques that use a substantial proportion of health care resources. Although both techniques increase coronary blood flow, they have fundamental differences beyond initial cost and inconvenience and discomfort to patients. PTCA reconstructs the coronary lumen and improves flow while maintaining future revascularization options. Progression of atherosclerosis favors proximal vessels, whereas CABG places conduits to distal locations that are mostly immune from advancing disease. Venous conduits, however, do deteriorate substantially with time. In a specific patient, technical or clinical factors may preclude 1 or both procedures. Where both are alternatives, solid trial data based on natural history observations have not been available to guide the selection process.
The report from CABRI, amplified by the meta-analysis by Pocock and colleagues, is an important contribution to the process of defining the relative roles of CABG and PTCA in patients with stable coronary artery disease. When the primary clinical end points of death and MI were analyzed, the 2 procedures appeared to have equal benefit. Randomized patients were highly selected, however, because only 4.6% of all patients who needed revascularization were actually randomized. This implies that the process of assessing a patient's suitability for each procedure is an important first step in clinical practice and that the investigators' conclusion of equivalence applies only when both options exist.
Despite this equivalence for survival and MI, there is the expected but nonetheless disquieting news that the need for further revascularization procedures and the level of angina were significantly greater in patients who received coronary artery reconstruction with PTCA than in patients who had CABG. Additional procedures are needed because of the elastic recoil and proliferative response that can be identified angiographically in 40% of patients treated with PTCA. Although most patients treated with PTCA remain asymptomatic and do not require further procedures, restenosis has substantial clinical and economic importance. Patients should be made aware of this fact when options are being discussed. At present, the initial cost advantage of PTCA is considerably reduced by the need for repeated procedures.
Two important qualifications should be made on the repeat procedure issue. First, several randomized trials required follow-up angiography whether the patients were symptomatic or not. Restenosis is common angiographically but is of clinical concern in only 20% of patients. Although there is no justification for redilating asymptomatic lesions, repeated PTCA and a crossover to CABG in response to angiographic restenosis without symptoms occurred; this finding magnifies the apparent clinical importance of restenosis.
Second, the PTCA technique has undergone major improvements since trial completion, in particular, the introduction of intracoronary stents. These devices buttress the artery after balloon dilation, largely eliminate elastic recoil, and reduce restenosis. In both the Benestent Study Group (1) and the Stent Restenosis Study (STRESS) (2), trials that compared stenting with ordinary balloon PTCA, stenting reduced the incidence of clinical restenosis by 50%. Further reductions seem certain with improved delivery and anticoagulation strategies. Because stenting was not used in CABRI and other trials referred to in the subject meta-analysis, there is reason to believe that the large repeated-procedure differential noted is greater than that reported in the current “stent era.”
Although the reviewed trials are helpful in the procedure selection process, careful consultation with surgeons and interventional cardiologists as to the suitability of the procedures will continue to be an essential part of decision making when the medical management of patients with coronary artery disease has failed.
Merril L. Knudtson, MD
Foothills HospitalCalgary, Alberta, Canada
1. Serruys PW, de Jaegere P, Kiemeneij F, et al. A comparison of balloon-expandable-stent implantation with balloon angioplasty in patients with coronary artery disease. Benestent Study Group. N Engl J Med. 1994;331:489-95.
2. Fischman DL, Leon MB, Bairn DS, et al. A randomized comparison of coronary-stent placement and balloon angioplasty in the treatment of coronary artery disease. Stent Restenosis Study Investigators. N Engl J Med. 1994;31:486-501.