Mortality Predictors in the Surgical Treatment of Active Infective Endocarditis

Abstract Introduction: Active infective endocarditis is associated with high morbidity and mortality. Surgery is indicated in high-risk conditions, and the main determinants of mortality in surgical treatment should be evaluated. Objective: To identify mortality predictors in the surgical treatment of active infective endocarditis in a long-term follow-up. Methods: This prospective observational study involved 88 consecutive patients diagnosed with active infective endocarditis, who underwent surgery between January 2005 and December 2015. Fifty-eight (65.9%) patients were male, the mean age was 50.87±16.15 years. A total of 31 (35.2%) patients had a history of rheumatic fever; 48 (54.5%) had had heart surgery with prosthetic valve implantation; 45 (93.8%) had biological prosthetic valve endocarditis and 3 (6.3%) mechanical prosthetic valve; 40 (45.5%) patients had the disease in their native valve. The mean EuroSCORE II was 8.9±6.5%, and the main surgical indication was refractory heart failure in 38 (43.2%) patients. A total of 68 bioprosthesis (36 aortic, 32 mitral) and 29 mechanical prostheses (12 aortic, 17 mitral) were implanted and three mitral valve plasties performed. A total of 25 (28.4%) patients underwent double or triple valve procedures. Aortic annulus reconstruction by abscess was performed in 18 (20.5%) and six (6.81%) patients had combined procedure. The mean surgery time was 359±97.6 minutes. Results: The overall survival in up to a 10-year follow-up period was 79.5%. In the univariate analysis, the main mortality predictors were positive blood cultures (P=0.003), presence of typical microorganisms (P=0.008), most frequently Streptococcus viridans (12 cases; 25%); C-reactive protein (hazard ratio [HR] 1.034, 95% confidence interval [CI] 1.000 to 1.070, P=0.04); creatinine clearance (HR 0.977, 95% CI 0.962 to 0.993, P=0.005); length of surgery: every five minutes multiplies the chance of death 1.005-fold (HR 1.005, 95% CI 1.001 to 1.009, P=0.0307); age (HR 1.060, 95% CI 1.026 to 1.096, P=0.001); and EuroSCORE II (HR 1.089, 95% CI 1.030 to 1.151, P=0.003). Conclusion: A positive blood culture with typical microorganism, C-reactive protein, age, EuroSCORE II, total surgical time and the presence of postoperative complications were the major predictors of mortality and significantly impacted survival in up to a 10-year follow-up period.

摘要：
引言：活动性感染性心内膜炎（active infective endocarditis）伴随较高的发病率与死亡率。高危临床场景下需实施外科手术治疗，因此需系统评估外科治疗方案中影响患者死亡率的核心因素。
研究目的：明确长期随访条件下，活动性感染性心内膜炎外科治疗的死亡率预测因子。
研究方法：本前瞻性观察研究纳入2005年1月至2015年12月期间接受外科手术治疗的88例连续性活动性感染性心内膜炎确诊患者。其中男性58例（占比65.9%），平均年龄为50.87±16.15岁。31例（35.2%）患者存在风湿热病史；48例（54.5%）曾接受人工瓣膜植入心脏手术；45例（93.8%）为生物瓣感染性心内膜炎，3例（6.3%）为机械瓣感染性心内膜炎；40例（45.5%）患者病变累及自体瓣膜。患者平均EuroSCORE II（欧洲心脏手术风险评估系统II）评分为8.9±6.5%，主要手术指征为难治性心力衰竭，共涉及38例（43.2%）患者。本次研究共植入68枚生物瓣（主动脉瓣36枚、二尖瓣32枚）与29枚机械瓣（主动脉瓣12枚、二尖瓣17枚），并完成3例二尖瓣成形术。25例（28.4%）患者接受双瓣或三瓣联合手术。18例（20.5%）患者因瓣周脓肿行主动脉瓣环重建术，6例（6.81%）患者接受多术式联合手术。平均手术时长为359±97.6分钟。
研究结果：最长10年随访周期内的总体生存率为79.5%。单因素分析显示，主要的死亡率预测因子包括：血培养阳性（P=0.003）、典型致病微生物检出（P=0.008），其中最常见的致病菌为草绿色链球菌（12例，占比25%）；C反应蛋白（风险比[HR] 1.034，95%置信区间[CI] 1.000~1.070，P=0.04）；肌酐清除率（HR 0.977，95%CI 0.962~0.993，P=0.005）；手术时长：每延长5分钟，死亡风险升高1.005倍（HR 1.005，95%CI 1.001~1.009，P=0.0307）；患者年龄（HR 1.060，95%CI 1.026~1.096，P=0.001）；以及EuroSCORE II评分（HR 1.089，95%CI 1.030~1.151，P=0.003）。
研究结论：检出典型致病微生物的血培养阳性结果、C反应蛋白水平、患者年龄、EuroSCORE II评分、总手术时长以及术后并发症的发生情况，是10年随访期内患者死亡率的核心预测因子，且对患者长期生存率存在显著影响。