Antithrombotic Therapy in Patients With Mechanical and Biological Prosthetic Heart Valves lhul D. Stein, M.D., F.C.C.P., Chairman Joseph S. Alpert, M.D., F.C.C.P. jack Copeland, M.D. James E. Dalen, M.D., F.C.C.P. Steven Goldman, M.D. A. G. G. Turpie, M.D.

of the 1986 and 19892 consensus Recommendations committee were that patients with mechanical 1

prosthetic heart valves be treated with long-term warfarin, at a dose sufficient to prolong the prothrombin time (PT) ratio to 1.5 to 2.0 times control using North American thromboplastin. It was suggested that administration of dipyridamole is optional, unless the patient suffered a systemic embolism despite adequate therapy with warfarin. The level of the PT ratio that was recommended was based on retrospective data and nonrandomized trials. The present report, based on newer data, will try to assess the risks and benefits of various levels of the PT ratio according to the type of prosthetic valve and its site of insertion. MECHANICAL PROSTHETIC VALVES

Only a few investigations have addressed the risks and benefits of more than one level of the PT ratio. Saour and associates, 3 in a level II study that included patients with Beall, Starr-Edwards, Cutter-Smeloff, Bjork-Shiley, and St. Jude valves, compared the occurrence of thromboemboli in patients with a North American (NA) PT ratio of 1.3 to I. 7 (moderate level PT ratio) with those with a PT ratio of 2.3 to 2.7 (high level PT ratio). Moderate vs high levels of anticoagulation resulted in thromboembolic events in 4.0/100 patient-years vs 3. 7/100 patient-years (NS). Somewhat more than half of the thromboembolic events, 18 of 33 (55 percent) occurred in patients whose PT ratios (NA) were :51.3. A trend suggested that major bleeding was less frequent in patients who received moderate levels of anticoagulant, 0.9/100 patient-years vs 2.1/ 100 patient-years (NS). Minor bleeding was less frequent among those with moderate levels of PT ratio, 5.2/100 patient-years vs 10.1/100 patient-years (prio11s emholic evt'n!s dPspitt• low-i111t-11sity anticoagulation. Circulation 1988: 71l(suppl ll:l-60-1-77 Kopf CS. Hammond GL. Geha AS. t'I al. Long-lt•rm perforrnalll't' of the St. Jude Medical valv1·: low inddPnce of thromboemholism and ht>morrhagic t"mpliealious with mod1•st dost'S of warfarin. Circulation l91l7; 76(s11ppl :ll:lll-132 Czer LSC, Chaux A. Matloff JM. d al. 'l(•n-yt'ar t'Xpt'rit'nt'

Antithrombotic therapy in patients with mechanical and biological prosthetic heart valves.

Antithrombotic Therapy in Patients With Mechanical and Biological Prosthetic Heart Valves lhul D. Stein, M.D., F.C.C.P., Chairman Joseph S. Alpert, M...
1MB Sizes 0 Downloads 0 Views