A Systematic Review of the Prognostic Value of Cardiopulmonary Exercise Testing in Patients with Ischemic and...

The prognostic utility of cardiopulmonary exercise testing (CPET) in heart failure (HF) is well established; however, whether optimal CPET parameter thresholds differ across HF etiologies remains unclear. This systematic review aimed to determine how CPET-derived parameters and their prognostic threshold values differ, and their association with adverse outcomes, in patients with ischemic vs nonischemic cardiomyopathy.

Eligible studies assessed adult HF patients and reported outcomes of all-cause mortality, left ventricular assist device implantation, heart transplantation, or hospitalization. CPET parameters and associated threshold values were extracted, and risk of bias was assessed using the Joanna Briggs Institute checklist for cohort studies.

Four studies comprising 491 ischemic and 218 nonischemic HF patients were included. Peak oxygen consumption (pVO₂) was the only CPET parameter unanimously reported. In ischemic HF, the optimal pVO₂ thresholds, in mL/kg/min, were ≤ 14.10 (hazard ratio [HR] 3.3; confidence interval [CI]: 1.9-5.8), ≤ 10.0 (HR 0.76; CI: 0.59-0.98), ≤ 15.20, and ≤ 14.0 (used in one study as a guideline comparator), yielding a mean threshold of ≤ 13.33 mL/kg/min ( ± 2.28). In nonischemic HF, optimal thresholds in mL/kg/min were ≤ 14.60 (HR 4.30 [CI: 2.10-8.90]) and ≤ 14.0, yielding a mean of ≤ 14.30 mL/kg/min ( ± 0.42).

Significant heterogeneity was present in study design, patient populations, and CPET variables assessed. The few consistently assessed prognostic thresholds were similar across HF etiologies. Peak oxygen consumption (pVO₂) remains a robust prognostic marker in both ischemic and nonischemic cardiomyopathy. Although patients with ischemic cardiomyopathy generally have worse clinical profiles, this review suggests that no meaningful differences occur in a few key CPET prognostic thresholds, namely pVO₂, across etiologies. These findings support continued use of established guideline-recommended thresholds for risk stratification, irrespective of HF subtype, but require further confirmation.