Introduction: Haemodynamic gain index (HGI) is a novel haemodynamic parameter which can be obtained from cardiopulmonary exercise testing (CPX), but its association with sudden cardiac death (SCD) is not known. We aimed to assess the association of HGI with SCD risk in a long-term prospective cohort study. Methods: Haemodynamic gain index was calculated using heart rate and systolic blood pressure (SBP) measured in 1897 men aged 42-61 years during CPX from rest to peak exercise, using the formula: [(Heart rate max x SBPmax) - (Heart rate rest x SBPrest)]/(Heart rate rest x SBPrest). Cardiorespiratory fitness (CRF) was measured using respiratory gas exchange analysis. Multivariable adjusted hazard ratios (HRs) (95% confidence intervals, CIs) were analyzed for SCD. Results: During a median follow-up of 28.7 years, 205 SCDs occurred. The risk of SCD decreased gradually with increasing HGI (p-value for non-linearity=.63). A unit (bpm/mmHg) higher HGI was associated with a decreased risk of SCD (HR 0.84; 95% CI 0.71–0.99), which was attenuated following adjustment for CRF. Cardiorespiratory fitness was inversely associated with SCD, which remained after further adjustment for HGI: (HR 0.85; 95% CI 0.77–0.94) per each unit higher CRF. Addition of HGI to a SCD risk prediction model containing established risk factors improved risk discrimination (C-index change=0.0096; p=.017) and reclassification (NRI=39.40%, p=.001). The corresponding values for CRF were (C-index change=0.0178; p=.007) and (NRI=43.79%, p=.001). Conclusion: Higher HGI during CPX is associated with a lower SCD risk, consistent with a dose-response relationship, but dependent on CRF levels. Though HGI significantly improves the prediction and classification of SCD beyond common cardiovascular risk factors, CRF remains a stronger risk indicator and predictor of SCD compared to HGI.


中文翻译：

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血液动力学增益指数与心源性猝死风险相关并改善风险预测：一项队列研究

简介：血流动力学增益指数（HGI）是一种新的血流动力学参数，可以通过心肺运动试验（CPX）获得，但其与心源性猝死（SCD）的关系尚不清楚。我们旨在通过一项长期前瞻性队列研究评估 HGI 与 SCD 风险的关联。方法：使用 1897 名 42-61 岁男性在 CPX 期间从休息到运动高峰期间测量的心率和收缩压 (SBP) 计算血流动力学增益指数，计算公式为：[(心率最大值 x SBP 最大值) - (心率)休息 x SBPrest)]/(心率休息 x SBPrest)。使用呼吸气体交换分析测量心肺健康（CRF）。对 SCD 进行多变量调整风险比 (HR)（95% 置信区间，CI）分析。结果：在中位随访 28.7 年期间，发生了 205 例 SCD。随着 HGI 的增加，SCD 的风险逐渐降低（非线性 p 值=.63）。HGI 升高一个单位 (bpm/mmHg) 与 SCD 风险降低相关（HR 0.84；95% CI 0.71–0.99），在对 CRF 进行调整后该风险降低。心肺健康与 SCD 呈负相关，在进一步调整 HGI 后仍然存在：（HR 0.85；95% CI 0.77–0.94）CRF 每升高一个单位。将 HGI 添加到包含既定风险因素的 SCD 风险预测模型中可以改善风险辨别（C 指数变化=0.0096；p=.017）和重新分类（NRI=39.40%，p=.001）。CRF 的相应值为（C 指数变化=0.0178；p=.007）和（NRI=43.79%，p=.001）。结论：CPX 期间较高的 HGI 与较低的 SCD 风险相关，与剂量反应关系一致，但取决于 CRF 水平。尽管 HGI 显着改善了 SCD 的预测和分类，超越了常见的心血管危险因素，但与 HGI 相比，CRF 仍然是 SCD 的更强的风险指标和预测因子。