Department of Surgery, McMaster University, Hamilton, Ontario, Canada.
Department of Health Research Methods, Evidence and Impact, McMaster University, Hamilton, Ontario, Canada.
Thromb Haemost. 2018 May;118(5):906-913. doi: 10.1055/s-0038-1637755. Epub 2018 Apr 3.
Guidelines recommend higher international normalized ratio (INR) targets for patients with mechanical valves believed to be at higher risk for thromboembolism. Higher INR targets are associated with increased bleeding risk. We performed a systematic review and meta-analysis assessing effects of lower and higher INR targets on thromboembolic and bleeding risk in patients with mechanical heart valves.
We searched Cochrane CENTRAL, MEDLINE and EMBASE for randomized controlled trials (RCTs) evaluating lower versus higher INR targets for adults with bileaflet mechanical valves. We performed title and abstract screening, full-text review, risk of bias evaluation and data collection independently and in duplicate. We pooled data using a random effects model and used the Grading of Recommendations Assessment, Development and Evaluation framework to evaluate overall quality of evidence.
We identified six RCTs ( = 5,497). Lower INR targets were associated with significantly less bleeding-22% versus 40% (relative risk [RR]: 0.54, 95% confidence interval [CI]: 0.31, 0.93, = 0.03, very low quality). There was no difference in thromboembolism-2% in both groups (RR: 1.28, 95% CI: 0.88, 1.85, = 0.20, very low quality) or mortality-5.5% with lower INR targets versus 8.5% (RR: 1.00, 95% CI: 0.82, 1.21, = 0.47, moderate quality).
In patients with mechanical valves, higher INR targets are not supported by current evidence, which is of very low quality. In fact, our systematic review suggests that lower INR targets offer significantly lower bleeding risks with no significant difference in thromboembolic risk.
指南建议机械瓣患者的国际标准化比值（INR）目标值更高，这些患者被认为有更高的血栓栓塞风险。更高的 INR 目标值与出血风险增加相关。我们进行了一项系统评价和荟萃分析，评估了机械心脏瓣膜患者较低和较高 INR 目标值对血栓栓塞和出血风险的影响。
我们在 Cochrane 中心数据库、MEDLINE 和 EMBASE 中搜索了评估成人双叶机械瓣患者较低与较高 INR 目标值的随机对照试验（RCT）。我们独立地并重复进行了标题和摘要筛选、全文审查、偏倚风险评估和数据收集。我们使用随机效应模型汇总数据，并使用推荐评估、制定与评价框架对总体证据质量进行评估。
我们确定了六项 RCT（ = 5497 例）。较低的 INR 目标值与明显较少的出血相关-22%与 40%（相对风险 [RR]：0.54，95%置信区间 [CI]：0.31，0.93， = 0.03，极低质量）。两组之间的血栓栓塞事件无差异-2%（RR：1.28，95%CI：0.88，1.85， = 0.20，极低质量）或死亡率-5.5%较低 INR 目标值与 8.5%（RR：1.00，95%CI：0.82，1.21， = 0.47，中等质量）。
在机械瓣患者中，目前的证据不支持较高的 INR 目标值，证据质量极低。实际上，我们的系统评价表明，较低的 INR 目标值可显著降低出血风险，而血栓栓塞风险无显著差异。
