Institute of Clinical Medicine, Department of Medicine, University of Eastern Finland, Kuopio, Finland; Central Finland Health Care District, Department of Medicine, Jyväskylä, Finland; Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland.
Kuopio Research Institute of Exercise Medicine, Kuopio, Finland; Department of Clinical Physiology and Nuclear Medicine, Kuopio University Hospital, Kuopio, Finland.
Prog Cardiovasc Dis. 2021 Sep-Oct;68:12-18. doi: 10.1016/j.pcad.2021.09.001. Epub 2021 Sep 29.
Cardiorespiratory optimal point (COP) during exercise, a potentially useful submaximal cardiopulmonary exercise testing (CPET) variable, may be an independent risk factor for cardiovascular disease outcomes. However, the relationship of COP with risk of sudden cardiac death (SCD) has not been previously investigated. We sought to evaluate the association between COP during exercise and SCD risk and determine whether COP improves SCD risk prediction.
COP, the minimum value of the ventilatory equivalent for oxygen (VE/VO2) in a given minute of a CPET, was ascertained in 2190 men who underwent clinical exercise testing. Hazard ratios (HRs) (95% confidence intervals [CIs]) and measures of risk discrimination for SCD were calculated.
A total of 240 SCDs death occurred during a median follow-up of 28.8 years. COP was linearly associated with SCD in a dose-response manner. In a multivariable model comprising several established and emerging CVD risk factors, the HR (95% CI) for SCD was 2.51 (1.36-4.62) per standard deviation increase in COP. This was minimally attenuated to 2.36 (1.27-4.37) on further adjustment for high sensitivity C-reactive protein. The association did not vary importantly in several relevant clinical subgroups. Addition of COP to a SCD risk score was associated with a C-index change of 0.0086 (0.0005 to 0.0167; p = .038) and difference in -2 log likelihood (p = .017).
COP during exercise is strongly, inversely and independently associated with SCD in a graded fashion. COP during exercise may potentially be used for the prediction of the long-term risk for SCD beyond established CVD risk factors.
运动时的心肺最佳点（COP）是心肺运动测试（CPET）的一个潜在有用的亚最大变量，可能是心血管疾病结局的独立危险因素。然而，COP 与心脏性猝死（SCD）风险的关系尚未被研究过。我们旨在评估运动时 COP 与 SCD 风险之间的关联，并确定 COP 是否能改善 SCD 风险预测。
在 2190 名接受临床运动测试的男性中，确定了 CPET 中某一分钟的最小通气当量氧值（VE/VO2）的 COP。计算了 SCD 的风险比（HR）（95%置信区间[CI]）和风险区分度量。
在中位数为 28.8 年的随访期间，共发生了 240 例 SCD 死亡。COP 与 SCD 呈线性剂量反应关系。在包含多个既定和新兴心血管疾病危险因素的多变量模型中，COP 每增加一个标准差，SCD 的 HR（95%CI）为 2.51（1.36-4.62）。进一步调整高敏 C 反应蛋白后，该值最小程度地降低至 2.36（1.27-4.37）。在几个相关的临床亚组中，这种关联没有重要的变化。将 COP 添加到 SCD 风险评分中，与 C 指数的变化相关，变化值为 0.0086（0.0005 至 0.0167；p=0.038），-2 对数似然值的差异为 0.017（p=0.017）。
运动时的 COP 与 SCD 呈强烈、反向和独立的梯度相关。运动时的 COP 可能可用于预测长期的 SCD 风险，超过既定的心血管疾病危险因素。
