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Belgian-Netherlands STENT Study II (Pilot) - BENESTENT II
Description:
PTCA vs. heparin-coated stents for mortality in stable angina.
Hypothesis:
Delaying and eliminating anticoagulant therapy in patients receiving a heparin-coated stent in conjunction with antiplatelet drugs is safe.
Study Design
Study Design:
Patients Screened: Not given
Patients Enrolled: 827
Mean Follow Up: 6 months
Patient Populations:
Scheduled to undergo coronary angioplasty because of stable angina for a single new lesion in a coronary artery
Target lesion <15mm long, located in a vessel > 3mm in diameter that supplied a normally-functioning myocardium
Suitable candidate for coronary bypass surgery
Exclusions:
Ostial lesion
A lesion at bifurcation
A lesion in previously grafted vessel
Intracoronary thrombus suspected
Contraindications to anticoagulant or antiplatelet therapy
Primary Endpoints:
Death
Occurrence of a cerebrovascular accident
Myocardial infarction (MI)
Need for coronary bypass surgery
Second percutaneous intervention involving the previously-treated lesion, either at the time of the initial procedure or during subsequent 6 months
Angiographic end point: minimal luminal diameter at follow-up
Secondary Endpoints:
Angiographic success rate (< 50% stenosis on visual assessment)
Procedural success rate (< 50% stenosis on quantitative assessment, without the occurrence of clinical events during hospital stay)
Functional class using Canadian Cardiovascular Society classification at 6 months or at the time of intercurrent angiography and second intervention
Results of exercise testing at 6 months or earlier, if clinically indicated
Rate of restenosis (> 50% at follow-up ) at 6 months
Drug/Procedures Used:
Stents: Palmaz-Schatz PS 153 coronary stents, 15mm long with a central articulation, coated with a modified version of Carmeda Bioactive Surface (Carmeda AB). Base layers were polyethylene imine and dextran sulfate. Aldehyde-terminated heparin (porcine mucosal origin) was covalently bonded to the polyethylene imine layer.
Phase 1:
Coumadin from day of stent implant for 3 months
Heparin, bolus dose (10,000 IU) at start of procedure, reinstituted as continuous infusion 6 h after removal of sheath. Gradually decreased when international normalized ratio within therapeutic range (2.5 to 3.5) for >36 h.
Phase 2:
Coumadin from day of stent implant for 3 months
Heparin, bolus dose (10,000 IU) at start of procedure, reinstituted as continuous infusion 12 h after removal of sheath. Gradually decreased when international normalized ratio within therapeutic range (2.5 to 3.5) for >36 h.
Phase 3:
Coumadin from day of stent implant for 3 months
Heparin, bolus dose (10,000 IU) at start of procedure, reinstituted as continuous infusion 36 h after removal of sheath. Gradually decreased when international normalized ratio within therapeutic range (2.5 to 3.5) for >36 h.
Phase 4:
Ticlopidine, 250 mg qd from day of stent implant for 1 month
Heparin during procedure only
Concomitant Medications:
All patients:
Aspirin, 250-500 mg qd for 6 months
Diltiazem 120 mg bid during hospitalization
Principal Findings:
Benestent II pilot:
Implantation of a heparin-coated stent was successful in 98% of patients.
Stent thrombosis did not occur during all 4 phases.
Overall clinical success rate at discharge was 99%.
Bleeding complications requiring blood transfusion or surgery fell from 7.% in phase 1 to 5.9%, 4%, and 0% in the subsequent 3 phases.
Hospital stay was 7.4, 6.1, 7.2, and 3.1 days for the consecutive phases.
The restenosis rate for the combined 4 phases was 13%: 15% in phase 1, 20% in phase 2, 11% in phase 3, and 6% in phase 4.
At 6 months, 86% of patients were event free (84%, 75%, 94% and 92% for Phases 2 through 4).
A cost analysis based on data from the BENESTENT-I and BENESTENT-II pilot study estimated the costs per additional event-free survivor after 7 months at Dfl 88,315, Dfl 28,127 and Dfl 6747 using respectively the results from the BENSTENT-I study, the BENESTENT-II pilot study and phase IV of the BENESTENT-II pilot study.
Benestent II main trial:
At 6 months, a primary clinical endpoint had occurred in 53 (12.8%) of 413 patients in the stent group and 79 (19.3%) of 410 in the angioplasty group (p=0.013). This significant difference in clinical outcome was maintained at 12 months.
In the subgroup assigned to angiographic follow-up, the mean minimum lumen diameter was greater in the stent group than in the balloon-angioplasty group, (1.89 [SD 0.65] vs 1.66 [0.57] mm, p=0.0002), which corresponds to restenosis rates (diameter stenosis > or =50%) of 16% and 31% (p=0.0008).
In the group assigned to clinical follow-up alone, event-free survival rate at 12 months was higher in the stent group than the balloon-angioplasty group (0.89 vs 0.79, p=0.004) at a cost of an additional 2085 Dutch guilders (US$1020) per patient.
Interpretation:
The implantation of stents coated with polyamine and end-point attached heparin in stable patients with one significant de novo lesion is well tolerated, is associated with no subacute stent thrombosis, and results in a favorable event-free status in 6 months. Over 12-month follow-up, a strategy of elective stenting with heparin-coated stents is more effective but also more costly than balloon angioplasty.
References:
1. Circulation 1996; 93: 412-422 Pilot study
2. Lancet. 352(9129):673-81, 1998 Final results
Keywords: Follow-Up Studies, Platelet Aggregation Inhibitors, Angina, Stable, Dextran Sulfate, Warfarin, Heparin, Disease-Free Survival, Ticlopidine, Constriction, Pathologic, Angioplasty, Balloon, Coronary, Stents, Length of Stay, Survivors, Blood Transfusion, International Normalized Ratio, Polyethylenes, Thrombosis, Imines, Polyamines
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