Anaemia and mortality in patients with transcatheter aortic valve replacement: a systematic review and meta-analysis

Objective: This study was done to determine the relationship between pre-procedural anaemia and mortality post transcatheter aortic valve replacement (TAVR). Introduction: TAVR is now a treatment option for patients with severe aortic stenosis (AS) with high surgical risk. Anaemia is a common comorbidity in the TAVR population. Small studies have suggested that anaemia is associated with worse short-term and long-term mortality in patients who underwent TAVR. However, there are no meta-analyses to further assess this association. Method: Studies were systematically searched from electronic databases (EMBASE and MEDLINE). Inclusion criteria were adult population with aortic stenosis who underwent TAVR, and number of patients with pre-procedural anaemia reported. Outcomes were short-term mortality or long-term mortality. Pooled effect size was calculated with a random-effect model, weighted for the inverse of variance. Heterogeneity was assessed with I2. Results: Six studies were included in the final analysis. Of these, pooled analysis of four studies examining association between anaemia and 30-day mortality did not show a statistically significant relationship. A pooled analysis of four studies examining the association of anaemia and long-term mortality after TAVR showed pooled adjusted risk ratio (RR) of 1.43, 95% CI 1.22–1.67 with low heterogeneity (I2 = 33%). Subgroup analysis after exclusion of one smaller study showed that the association remained significant (RR 1.41, 95% CI 1.27–1.56) with decreased heterogeneity (I2 = 0%). Conclusion: This systematic review and meta-analysis found an association between pre-procedural anaemia and increased long-term but not short-term mortality after TAVR. Further study of the pathophysiology underlying this association is needed.

研究目的：本研究旨在明确经导管主动脉瓣置换术（transcatheter aortic valve replacement, TAVR）术前贫血与术后死亡率之间的关联。研究背景：目前，经导管主动脉瓣置换术（TAVR）已成为外科手术高风险重度主动脉瓣狭窄（aortic stenosis, AS）患者的治疗选择。贫血是TAVR患者群体中常见的合并症。既往小型研究表明，接受TAVR的患者若合并术前贫血，其短期及长期死亡率均更高。然而目前尚无荟萃分析对该关联开展进一步评估。研究方法：本研究通过EMBASE与MEDLINE两大电子数据库进行系统文献检索。纳入标准为：接受TAVR治疗的成人主动脉瓣狭窄患者，且研究报告了术前贫血患者的例数。研究结局指标为短期死亡率或长期死亡率。采用随机效应模型计算合并效应量，以方差倒数进行加权分析。通过I²值评估研究间异质性。研究结果：最终共纳入6项研究进行最终分析。其中，针对贫血与30天死亡率关联的4项研究的合并分析未显示出具有统计学意义的关联。针对贫血与TAVR术后长期死亡率关联的4项研究的合并分析显示，校正后的合并风险比（risk ratio, RR）为1.43，95%置信区间（confidence interval, CI）为1.22~1.67，研究间异质性较低（I²=33%）。在排除1项规模较小的研究后进行亚组分析，结果显示该关联仍具有统计学意义（RR=1.41，95%CI：1.27~1.56），且研究间异质性进一步降低至0%。研究结论：本系统综述与荟萃分析发现，TAVR术前贫血与患者术后长期死亡率升高存在显著关联，但与短期死亡率无统计学相关性。未来仍需进一步阐明该关联背后的病理生理学机制。