Cardiopulmonary exercise test criteria for heart transplantation referral of patients with ambulatory heart failure in the current era

A recent study suggests that the traditional threshold used to refer heart failure (HF) patients for heart transplantation may need to be reconsidered.

Current guidelines recommend transplant evaluation when peak VO₂ is below 12 mL/kg/min. However, these recommendations are based on older data. Researchers analyzed over 8,000 patients with ambulatory HF who underwent cardiopulmonary exercise testing (CPET), focusing on those with reduced ejection fraction and peak VO₂ <12.

They found that these patients often had better short- and mid-term survival than heart transplant recipients, with survival curves crossing only after about 2.7 years. This indicates that peak VO₂ alone may not accurately identify patients at highest short-term risk.

Two additional CPET parameters—ventilatory efficiency (VE/VCO₂ slope) and exercise oscillatory ventilation (EOV)—provided important prognostic information. Patients with a favorable VE/VCO₂ slope (≤34) or without EOV had significantly lower long-term mortality. When combined, these measures identified distinct risk groups with clearly different outcomes.

The study concludes that peak VO₂ <12 mL/kg/min alone may no longer be sufficient to guide transplant referral, and that a more comprehensive CPET evaluation can improve risk stratification in modern HF care.