Optimal Coronary Balloon Angioplasty With Provisional Stenting vs. Stent Trial - OCBAS
OCBAS was designed to compare angiographic restenosis and target vessel revascularization (TVR) of lesions treated with coronary stenting versus those treated with optimal PTCA.
The restenosis rate at 6 months would be lower in lesions treated with primary elective stenting versus those treated with optimal balloon angioplasty.
Patients Screened: 953
Patients Enrolled: 116
NYHA Class: not reported
Mean Follow Up: 6 months (angiographic) and 1 year (clinical)
Mean Patient Age: not reported
Mean Ejection Fraction: not reported
successful PTCA residual diameter stenosis =30%, determined by on-line quantitative coronary angiography (QCA) no major dissections visualized in the first angiogram of the index artery after the last balloon inflation
lesions >20 mm in length lesions in coronary artery bypass grafts vessels with unsuitable anatomy for stenting (reference diameter <2.5 mm, diffuse disease, severe left main stenosis, severe vessel tortuosity) lesions with acute complications or suboptimal results during PTCA treatment with interventional devices other than balloon angioplasty contraindications for anticoagulation or antiplatelet therapy, aspirin or ticlopidine hypersensitivity noncardiac illness with less than 1-year life expectancy
Angiographic restenosis (>=50% stenosis of the index artery) at 6-month follow-up Target vessel revascularization at 6-month follow-up
Composite of event-free survival (freedom from death, myocardial infarction, angina and TVR) at 6-month follow-up Costs analysis
Following successful PTCA, patients were randomly assigned to either the stent or the optimal PTCA groups. If early loss (>0.3 mm loss in MLD and/or >10% increase in the diameter stenosis) was seen in the repeat 30 minute angiogram, patients crossed over to the stent group (provisional stenting).
Aspirin 325 mg/day for at least 24 h before the procedure. Weight-based IV heparin bolus was given to achieve an ACT >280 s during the procedure. Ticlopidine 250 mg twice a day orally for 4 weeks was given to patients receiving stents. Calcium channel antagonist for 3 months.
Among patients in the PTCA group, 13.5% crossed over to stent due to early loss. Length of hospital stay was similar in both the stent and optimal PTCA groups (3.2 ± 1 vs. 2.4 ± 2 days, respectively). Acute gain was significantly higher in the stent group than in the PTCA group (1.95 vs. 1.5 mm, p<0.03). However, late loss was significantly higher in the stent than the PTCA group (0.63 ± 0.59 vs. 0.26 ± 0.44, p=0.01). As a result, net gain with both techniques was similar (1.32 vs 1.24 mm p=NS). At 6 month follow-up, both the angiographic restenosis rate (19.2% for stent vs 16.4% for PTCA, p=NS) and TVR (17.5% for stent vs 13.5% for PTCA, p=NS) were similar between the two groups. Event-free survival did not differ in the two treatment arms (80.8% for stent vs 83.1% for PTCA, p=NS). Overall costs (hospital and follow-up) were significantly higher in the stent arm vs the PTCA arm (US $591,740 vs US $398,480 p<0.02).
Unlike the BENESTENT I and STRESS trials, which showed a 30% reduction in late restenosis with the use of stents, angiographic restenosis in OCBAS was similar between PTCA and stented patients, as was length of hospital stay, TVR and freedom from major cardiac events. Despite the lack of benefit observed, overall costs were significantly higher in the stent than in the optimal PTCA with provisional stenting group. Despite a small sample size, the OCBAS trial suggests immediate use of coronary stents following optimal PTCA may not be warranted, but rather a delayed, conservative approach may result in similar outcomes. Given the conflicting results with trials such as DEBATE II, which showed higher costs with provisional stenting, further trials are needed before a definitive conclusion can be drawn. Finally, waiting 30 minutes to examine the early loss may not be feasible in clinical practice, and the trial was initiated before the availability of later generations of stents and does not include the use of coated stents.
J Am Coll Cardiol 1998 Nov;32(5):1351-1357.
Keywords: Follow-Up Studies, Coronary Angiography, Heparin, Coronary Disease, Disease-Free Survival, Ticlopidine, Constriction, Pathologic, Angioplasty, Balloon, Coronary, Stents, Calcium
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