Cannegieter S C, Rosendaal F R, Briët E
Department of Hematology, University Hospital Leiden, The Netherlands.
Circulation. 1994 Feb;89(2):635-41. doi: 10.1161/01.cir.89.2.635.
Patients with mechanical heart valve prostheses may experience valve thrombosis and subsequent systemic embolism for which they are treated with oral anticoagulant therapy. It is essential to know reliable estimates of the risks and benefits of this therapy in order to answer a number of clinical questions rationally. We sought to obtain more precise estimates of the risks and benefits by combining the data from individual studies by using meta-analysis.
We searched for studies in which the incidences were reported of embolic or bleeding complications in patients with mechanical heart valve prostheses. They were collected from the Medline and Current Contents database and by cross-references between 1970 and 1992. Since most studies vary greatly in many respects, we used a number of inclusion criteria, thus selecting comparable studies of acceptable quality only. The influence of antithrombotic therapy, valve position, and valve type was analyzed by univariate and by multivariate analysis with Poisson regression techniques. Forty-six studies were found, including 13,088 patients studied for 53,647 patient-years. We found an incidence of major embolism in the absence of antithrombotic therapy of 4 per 100 patient-years. With antiplatelet therapy this risk was 2.2 per 100 patient-years, and with coumarin therapy it was reduced to 1 per 100 patient-years. This risk varied with the type and the site of the prosthesis. A prosthesis in mitral position increased the risk almost twice as compared with the aortic position. Tilting disc valves and bileaflet valves showed a lower incidence of major embolism than caged ball valves. An incidence of major bleeding was found in patients treated with coumarin derivatives of 1.4 per 100 patient-years. The incidence of bleeding became significantly higher with the addition of antiplatelet therapy, although this did not decrease the risk of thromboembolism any further.
These data provide a reference for future studies and give adequate risk estimates for clinical decision making.
机械心脏瓣膜置换患者可能会发生瓣膜血栓形成及随后的全身栓塞，对此需采用口服抗凝治疗。为合理回答一系列临床问题，了解该治疗的风险和获益的可靠评估至关重要。我们试图通过荟萃分析合并个体研究数据来获得更精确的风险和获益评估。
我们检索了报告机械心脏瓣膜置换患者栓塞或出血并发症发生率的研究。这些研究是从1970年至1992年的医学索引数据库和《现刊目次》数据库以及通过交叉引用收集的。由于大多数研究在许多方面差异很大，我们采用了一些纳入标准，仅选择质量可接受的可比研究。采用泊松回归技术通过单变量和多变量分析来分析抗血栓治疗、瓣膜位置和瓣膜类型的影响。共找到46项研究，包括13088例患者，研究时间达53647患者年。我们发现，在未进行抗血栓治疗的情况下，严重栓塞发生率为每100患者年4例。采用抗血小板治疗时，该风险为每100患者年2.2例，采用香豆素治疗时，该风险降至每100患者年1例。该风险因假体类型和部位而异。二尖瓣位假体的风险比主动脉瓣位增加近一倍。倾斜碟瓣和双叶瓣的严重栓塞发生率低于笼球瓣。接受香豆素衍生物治疗的患者严重出血发生率为每100患者年1.4例。加用抗血小板治疗后出血发生率显著升高，尽管这并未进一步降低血栓栓塞风险。
这些数据为未来研究提供了参考，并为临床决策提供了充分的风险评估。
