Prognostic impact of postprocedure stroke volume in patients with low-gradient aortic stenosis

Objective The effect of postoperative blood flow status on the prognosis of patients with low-gradient severe aortic stenosis (AS) has not been examined. Severe AS is associated with a higher mortality rate after transcatheter aortic valve implantation (TAVI). We examined the prognostic value of low-flow status by comparing stroke volume indices (SVi) before and after TAVI in patients with symptomatic, low-gradient severe AS. Methods A total of 1613 patients with severe symptomatic AS who underwent TAVI in 14 Japanese institutes for low-gradient severe AS (418 patients, median age 84 years, 32.5% men) were prospectively enrolled. The primary endpoint was cardiovascular mortality during follow-up after TAVI, and independent predictors were evaluated. Receiver operating characteristic curves were generated to determine the optimal cut-off value of post-TAVI SVi for predicting cardiovascular mortality, and the receiver operating characteristic curves of pre-TAVI and post-TAVI SVi were compared. Results The cardiovascular mortality rate was 4.1% (17 patients) during follow-up (median 9.2 months). Multivariate analysis revealed post-TAVI SVi to be an independent predictor of cardiovascular mortality (per 10 mL/m2 decrease; HR, 2.0; 95% CI 1.28 to 3.12). The optimal cut-off value of post-TAVI SVi was 41.4 mL/m2. Post-TAVI SVi showed significantly larger area under the curve than pre-TAVI SVi (0.74 (95% CI 0.69 to 0.79) vs 0.61 (95% CI 0.56 to 0.65), p<0.05). Conclusions Post-TAVI SVi is a better predictor of cardiovascular mortality than pre-TAVI SVi in patients with symptomatic low-gradient severe AS. Low-flow and low-normal-flow status (35≤ SVi <40 mL/m2) require careful management after TAVI.

目的 术后血流状态对低梯度重度主动脉瓣狭窄（AS）患者预后的影响尚未得到研究。重度AS与经导管主动脉瓣植入术（TAVI）后较高的死亡率相关。我们通过比较有症状的低梯度重度AS患者TAVI前后的每搏量指数（SVi），来检验低血流状态的预后价值。 方法 前瞻性纳入日本14家机构共1613例因低梯度重度AS接受TAVI的重度有症状AS患者（418例，中位年龄84岁，男性占32.5%）。主要终点是TAVI术后随访期间的心血管死亡率，并评估独立预测因素。绘制受试者工作特征曲线以确定TAVI术后SVi预测心血管死亡率的最佳截断值，并比较TAVI术前和术后SVi的受试者工作特征曲线。 结果 随访期间（中位9.2个月）心血管死亡率为4.1%（17例患者）。多变量分析显示TAVI术后SVi是心血管死亡率的独立预测因素（每降低10 mL/m²；风险比为2.0；95%置信区间为1.28 - 3.12）。TAVI术后SVi的最佳截断值为41.4 mL/m²。TAVI术后SVi曲线下面积显著大于TAVI术前SVi（0.74（95%置信区间0.69 - 0.79）对比0.61（95%置信区间0.56 - 0.65），P < 0.05）。 结论 在有症状的低梯度重度AS患者中，TAVI术后SVi比TAVI术前SVi能更好地预测心血管死亡率。低血流和低正常血流状态（35≤ SVi < 40 mL/m²）在TAVI术后需要谨慎处理。