Trujillo John F, Hollenberg Steven M
Cooper Medical School of Rowan University, 401 South Broadway, Camden, NJ 08103.
FP Essent. 2017 Jun;457:23-29.
Patients undergoing cardiac valve replacement may receive mechanical or bioprosthetic valves. Mechanical valves require lifelong anticoagulation but are durable and the need for a second surgery is up to eightfold times less than with bioprosthetic valves. Bioprosthetic valves do not require lifelong anticoagulation and thus are associated with fewer bleeding complications but they are less durable and associated with higher morbidity and mortality rates, particularly in younger patients. Anticoagulation with mechanical valves is achieved using warfarin; use of direct-acting oral anticoagulants is not indicated. Concomitant low-dose aspirin is recommended for patients with mechanical valves and as sole thromboembolism prophylaxis for patients receiving aortic or mitral bioprosthetic valves. If a patient taking warfarin is to undergo a surgical procedure that requires interruption of anticoagulation, bridging therapy with heparin is indicated if the patient has a mechanical aortic valve and any risk of thromboembolism, an older-generation mechanical aortic valve, or a mechanical mitral valve. Warfarin is teratogenic; pregnant women should take heparin. Patients with mechanical or bioprosthetic valves should receive antibiotic prophylaxis before some dental and surgical procedures to prevent endocarditis. Thrombolytic therapy should be considered in patients who develop a thrombus on a valve that does not resolve with heparin.
接受心脏瓣膜置换术的患者可植入机械瓣膜或生物瓣膜。机械瓣膜需要终身抗凝,但耐用性好,二次手术需求比生物瓣膜少八倍之多。生物瓣膜不需要终身抗凝,因此出血并发症较少,但耐用性较差,发病率和死亡率较高,尤其是在年轻患者中。机械瓣膜抗凝使用华法林,不建议使用直接口服抗凝剂。对于植入机械瓣膜的患者,建议同时使用低剂量阿司匹林,对于接受主动脉或二尖瓣生物瓣膜的患者,阿司匹林是唯一的血栓栓塞预防药物。如果服用华法林的患者要接受需要中断抗凝的外科手术,如果患者有机械主动脉瓣且有任何血栓栓塞风险、使用的是老式机械主动脉瓣或机械二尖瓣,则需要使用肝素进行桥接治疗。华法林具有致畸性,孕妇应使用肝素。植入机械瓣膜或生物瓣膜的患者在进行某些牙科和外科手术前应接受抗生素预防,以防止心内膜炎。对于瓣膜上形成血栓且肝素治疗无效的患者,应考虑溶栓治疗。