A Comparison of a Moderate with Moderate-high Intensity Oral Anticoagulant Treatment in Patients with Mechanical Heart Valve Prostheses

Abstract

SummaryBackground. The long-term administration of oral anticoagulants to patients with mechanical heart valve prostheses is generally accepted. However, the appropriate intensity of oral anticoagulant treatment in these patients is still controversial.Methods and Results. From March 1991 to March 1994, patients referred to the Padova Thrombosis Center who had undergone mechanical heart valve substitution at least 6 months earlier were randomly assigned to receive oral anticoagulants at moderate intensity (target INR = 3) or moderate-high intensity (target INR = 4). Principal end points were major bleeding, thromboembolism and vascular death. Minor bleeding was a secondary end-point.A total of 104 patients were assigned to the target 3 group and 101 to the target 4 group; they were followed for from 1.5 years to up 4.5 years (mean, 3 years). Principal end-points occurred in 13 patients in the target 3 group (4 per 100 patient-years) and in 20 patients in the target 4 group (6.9 per 100 patient-years). Major hemorrhagic events occurred in 15 patients, 4 in the target 3 group (1.2 per 100 patient-years) and 11 in the target 4 group (3.8 per 100 patient-years) (p = 0.019). The 12 recorded episodes of thromboembolism, 4 of which consisted of a visual deficit, were all transient ischemic attacks, 6 in the target 3 group (1.8 per 100 patient-years) and 6 in the target 4 group (2.1 per 100 patient- years). There were 3 vascular deaths in each group (0.9 and 1 per 100 patient-years for target 3 and target 4 groups, respectively). Minor bleeding episodes occurred 85 times (26 per 100 patient-years) in the target 3 group and 123 times (43 per 100 patient-years) in the target 4 group (p = 0.001).Conclusions. Mechanical heart valve patients on anticoagulant treatment who had been operated on at least 6 months earlier experienced fewer bleeding complications when maintained on a moderate intensity regimen (target INR = 3) than those on a moderate-high intensity regimen (target INR = 4). The number of thromboembolic events and vascular deaths did not differ between the two groups.

Ten-year experience with acenocoumarol treatment in an ambulatory cohort of Spanish patients

“…Previous studies have described an incidence of bleeding in patients with PHV about 3-5 for 100 patients-year with a wide range, from 1.0 to 8.3 for 100 patients-year. Therefore, we consider that the incidence found in our study (3.27 for 100 patients-years) is in consonance with those previous reports [2,[15][16][17][18].…”

Combined oral anticoagulants and antiplatelets: benefits and risks

“…However, despite anticoagulant therapy and the use of new generation prostheses, thromboembolic events continue to occur at a rate of about 0.71-2.1% per year in patients with mechanical valve prosthesis [16,17]. In this clinical setting, the clinical benefit of adding low-dose aspirin to conventional anticoagulation have been explored.…”

Low-Intensity Oral Anticoagulant Plus Low-Dose Aspirin During the First Six Months Versus Standard-Intensity Oral Anticoagulant Therapy After Mechanical Heart Valve Replacement: A Pilot Study of Low-Intensity Warfarin and Aspirin in Cardiac Prostheses (LIWACAP)

“…Major bleeding comprised the following: 1) Intracranial bleeding at CT scan; 2) retroperitoneal bleeding at CT scan; 3) ocular bleeding with blindness; 4) articular bleeding; 5) bleeding that reduced hemoglobin concentration by 2 g/dL or more or requiring the transfusion of two or more units of blood; 6) bleeding that required surgical intervention. Vascular death included sudden demise, V. PENGO ET AL defined as unexpected death occurring within 1 hour of the first symptom and that was not provoked by a nonvascular cause (14).…”