Changes in Pulmonary Function in Patients With Advanced Heart Failure Listed for Heart Transplantation

Background: Pulmonary function tests (PFTs) are often impaired in patients with advanced heart failure. There is limited data about their impact on survival after heart transplantation (HT). We sought to assess the prevalence and type of PFT abnormalities in patients on HT waiting list and their impact on outcomes.

Methods: We performed a retrospective analysis of a prospective registry of consecutive patients undergoing HT between 2012 and 2018. Patients were classified into 4 groups according to pre-HT PFT results: 1. normal pattern: forced vital capacity (FVC) ≥ 80% and forced expiratory volume in 1 second (FEV₁) to FVC ratio (FEV₁/FVC) ≥ 0.7; 2. obstructive: FEV₁/FVC < 0.7; 3. nonobstructive: FEV₁/FVC ≥ 0.7 and FVC < 80% when total lung capacity value was not available; and 4. restrictive: FEV₁/FVC ≥ 0.7 and total lung capacity < 80%. The prevalence of impaired carbon monoxide diffusing capacity corrected for hemoglobin < 80% and FEV₁ < 70% was also analyzed. High-urgency HT patients and those referred from other centers without quantitative pulmonary evaluation were excluded.

Results: Among 123 patients who underwent HT, 83 patients with complete PFT were included. Median follow-up was 2.7 ± 1.9 years. Of these, 29 (34.9%) had an obstructive pattern, 20 (24.1%) a nonobstructive, 18 (21.7%) a restrictive, and 16 (19.3%) a normal pattern. Fifty-one (61.4%) patients had FEV₁ < 70% and 58 (69.9%) a carbon monoxide diffusing capacity corrected for hemoglobin < 80%. There was a tendency to lower survival in all altered PFT groups compared with normal (P = .054) but not within the other groups. Patients with an impaired FEV₁ had significantly higher mortality than patients with normal values (P = .008). Area under receiver operating characteristic curve for FEV₁ was 0.73 (95% confidence interval [0.60-0.86]). A cutoff value of FEV₁ (60.5) predicts mortality with 66% sensitivity and 64% specificity.

Conclusions: PFT alterations have a very high prevalence on HT waiting list patients. Patients with impaired FEV₁ had worse outcomes after heart transplantation.