Kawczynski Michal J, van Kuijk Sander M J, Olsthoorn Jules R, Maessen Jos G, Kats Suzanne, Bidar Elham, Heuts Samuel
Department of Cardiothoracic Surgery, Maastricht University Medical Centre (MUMC+), Maastricht, The Netherlands.
Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands.
Eur J Cardiothorac Surg. 2025 Feb 4;67(2). doi: 10.1093/ejcts/ezaf022.
Previous analyses of the volume-outcome relationship have focused on short-term outcomes such as early mortality. The current study aims to update a novel statistical methodology, facilitating the evaluation of the relation between procedural volume and time-to-event outcomes such as long-term survival, using surgery for acute type A aortic dissection as an illustrative example.
This study employed an existing dataset of type A dissection outcomes, retrieved from literature. Studies were included when reporting on annual case load and long-term survival, which served as the primary outcome of interest. Individual patient data were reconstructed from the included studies, and a hazard ratio was determined per study in relation to overall survival, after which the calculated hazard ratios were incorporated in a restricted cubic-spline model, facilitating the application of the elbow method.
Fifty-two studies were included (n = 14 878 patients), with a median follow-up of 5 years. One-, 3-, 5- and 10-year survival of the overall cohort were 82% [95% confidence interval (CI) 82-83%], 79% (95% CI 78-80%), 74% (95% CI 74-75%) and 60% (95% CI 59-62%), respectively. A significant non-linear volume-outcome relation for long-term survival was observed in both the unadjusted and adjusted analyses (P = 0.030 and P = 0.002), with an optimal annual case load of 32 cases/year (95% CI 31-33).
Based on the available data, these findings imply that the annual case volume to achieve optimal long-term survival is located near a procedural volume of 32 cases/year. After accrual of more annual procedures, long-term survival may no longer significantly improve any further.
以往对手术量-预后关系的分析主要集中在短期预后，如早期死亡率。本研究旨在更新一种新的统计方法，以便以急性A型主动脉夹层手术为例，评估手术量与长期生存等事件发生时间预后之间的关系。
本研究采用从文献中检索到的A型夹层预后的现有数据集。纳入报告年度病例数和长期生存情况的研究，长期生存作为主要关注的预后指标。从纳入的研究中重建个体患者数据，每项研究确定与总生存相关的风险比，然后将计算出的风险比纳入受限立方样条模型，以便应用拐点法。
纳入52项研究（n = 14878例患者），中位随访时间为5年。整个队列的1年、3年、5年和10年生存率分别为82%[95%置信区间（CI）82 - 83%]、79%（95% CI 78 - 80%）、74%（95% CI 74 - 75%）和60%（95% CI 59 - 62%）。在未调整和调整分析中均观察到长期生存存在显著的非线性手术量-预后关系（P = 0.030和P = 0.002），最佳年度病例数为每年32例（95% CI 31 - 33）。
基于现有数据，这些发现表明，实现最佳长期生存的年度病例数接近每年32例的手术量。每年进行更多手术后，长期生存可能不再有显著进一步改善。
