Table 2.

Main comparative studies after bioprosthetic valve implantation with outcome focused on thromboembolic events, comparing warfarin with aspirin

Author-Year	N	Study design and follow-up (months)	Location and incidence of embolic events (%/person-year)	Stipulated therapy	Conclusion (embolic events)
Louagie et al8 1993	100	Retrospective; 70	MBP 2.01 overall	WAR x ASA	Previous MS and AF are predictors of permanent OA, mechanical prosthesis recommended.
			0.5 x 1.3
Blair et al23 1994	748	Retrospective; 3	ABP: 378 pts	WAR x ASA X NAT	BPM: WAR reduced events but increased bleeding; ABP: ASA was similar to WAR;
			WAR 2.9
			ASA: 0.8
			NAT: 1.5
			MBP: 370 pts
Heras et al9 1995	816	Retrospective; 99.6	0-10/10-90/> 90 d	Warfarin, dipyridamole and aspirin were used;	High risk of thromboembolism on the first 10 days; OA ≥ Reduced risk of embolism from 3.9% to 2.5%;
			ABP: 41/3.6/1.9
			MBP: 55/10/2.4
Aramendi et al24 1998	168	Retrospective; 38.4	ABP and MBP	Ti: 137 x WAR 40 x ASA 14 x NAT 18 pts	The first three months are high risk; Ti was superior to WAR.
			Ticlopidine 0.5
			Warfarin 3
Guerli et al25 2004	249	Prospective; Observational; 3	ABP	WAR 141 x ASA 108 pts	Similar incidence in both groups;
Ramos et al26 2004	184	Prospective; Observational; 3	APB	ASA 159 and WAR 25 pts	Embolism incidence of 18.25%/patient-year
			MBP
			18.25

N: sample size; AF: atrial fibrillation; ABP: aortic bioprosthesis; MBP: mitral bioprosthesis; NAT: No antithrombotic therapy; EF: ejection fraction; OA: oral anticoagulation; CVA: cerebrovascular accident; pts: Patients; Ti: Ticlopidine; WAR: Warfarin; ASA: Aspirin; MS: mitral stenosis.