CHANGING FROM INTENSIVE ANTICOAGULATION TO TREATMENT WITH ASPIRIN ALONE FOR CORONARY STENTS - THE EXPERIENCE OF ONE-CENTER IN THE UNITED-KINGDOM

Objective - To investigate whether an elective change in the anticoagu lation protocol for patients with coronary stents affected clinical ou tcomes and length of hospital stay. Design - Retrospective observation al study of a consecutive series of patients treated with coronary ste nts over an 18 month period from April 1994 to October 1995. Backgroun d - Intensive anticoagulation regimens are used in many UK centres to reduce the risk of coronary stent thrombosis. Recent data have called into question the necessity for full anticoagulation and favourable re sults have been reported with antiplatelet agents alone. The results f rom a tertiary referral centre were investigated during a period where an elective change in policy was made: an initial 70 patients were tr eated intensively with intravenous heparin and with warfarin and aspir in; subsequently 94 were treated with aspirin and deployment of a high pressure balloon only. Methods - Review of case notes, angiograms, an d a database of intervention procedures and telephone interview. Class ic epidemiological techniques, as well as linear regression and logist ic regression, were used to model the outcomes of major procedural com plications and length of hospital stay. Patients - 164 patients treate d with 196 coronary stents. Results - There were 22 (13.4%) major comp lications (coronary bypass grafting 11, subacute thrombosis 6, tampona de 2, myocardial infarction 1, death 2). With logistic regression, the risk of major complication was shown not to be affected by anticoagul ation (relative risk (RR) 1.03; P = 0.97). Significant determinants of risk included acute vessel closure as an indication for stenting (RR = 80.6; P < 0.001) and sex (male: female RR = 0.19; P = 0.02). The med ian length of stay (LOS) was 5 days (1-45). Use of a linear regression model showed that anticoagulation added 4.5 days and a major complica tion added a further 4.5 days to a baseline length of stay of 3.2 days (R(2) = 0.32; P < 0.001). Conclusion - This is a report of coronary s tenting as part of usual clinical practice in one British tertiary ref erral centre. In this experience, treatment with aspirin alone is prob ably as safe as intensive anticoagulation, and has the benefit of redu cing length of stay by more than 50% to 3.2 days in an uncomplicated c ase.