Anaerobic threshold and respiratory compensation point identification during CPET in chronic heart failure

Background. We evaluated the prognostic significance of the simple presence or absence of identifiable anaerobic threshold (AT) and respiratory compensation point (RCP) at cardiopulmonary exercise test (CPET) performed with a maximal incremental exercise protocol.
Methods. In the present multicenter study, we retrospectively analyzed data of 1995 reduced-ejection-fraction heart failure (HFrEF) patients. All underwent clinical and laboratory evaluation, echocardiography, and maximal CPET at baseline. The analysis was performed according to absence of identified AT and RCP (group 1, n=292, 15%), presence of AT but absence of identified RCP (group 2, n=920, 46%), and presence of both AT and RCP (group 3, n=783, 39%). The study endpoint was the composite of cardiovascular mortality/urgent heart transplantation/left ventricular assist device implantation.
Results. Median follow-up was 2.97 years (interquartile range 1.50–5.35 years). Eighty-seven (30%), 169 (18%), and 111 (14%) events were observed in group 1, 2, and 3, respectively (p= 0.025). Compared to group 3 (best survival patients), the likelihood of reaching the study endpoint increased 2.7 times when neither AT nor RCP were identified (HR 2.74), and 1.4 times when only AT was identified (HR=1.39). Moreover, adding the presence/absence of identified AT and RCP improved peak VO2 prognostic power, since a significant reclassification was obtained (3.57%, 95% CI 1.9%, 5.2%, p <0.001).
Conclusion. AT and RCP identification has a potential role in the prognostic stratification of HFrEF.

背景。本研究评估了在采用最大增量运动方案进行的心肺运动测试（CPET）中，可识别的无氧阈（AT）和呼吸补偿点（RCP）的存在与否对心衰患者预后的预测意义。方法。在本多中心回顾性研究中，我们对1995例减射分数心衰（HFrEF）患者的资料进行了分析。所有患者均接受了基线时的临床和实验室评估、超声心动图检查以及最大CPET。分析根据是否存在可识别的AT和RCP分为三组：未识别AT和RCP组（组1，n=292，15%）、存在AT但未识别RCP组（组2，n=920，46%）以及存在AT和RCP组（组3，n=783，39%）。研究终点为心血管死亡率/紧急心脏移植/左心室辅助装置植入的复合终点。结果。中位随访时间为2.97年（四分位间距1.50-5.35年）。在组1、2和3中分别观察到87例（30%）、169例（18%）和111例（14%）事件（p=0.025）。与组3（最佳存活患者组）相比，未识别AT和RCP时达到研究终点的可能性增加了2.7倍（HR 2.74），仅识别AT时增加了1.4倍（HR=1.39）。此外，引入AT和RCP的存在与否提高了峰值摄氧量（VO2）的预后能力，因为获得了显著的再分类效果（3.57%，95% CI 1.9%，5.2%，p <0.001）。结论。AT和RCP的识别在HFrEF的预后分层中可能具有重要作用。