Pulmonary function in chronic heart failure. Changes after heart transplantation

Abstract

To investigate the impact of chronic heart failure on pulmonary function in heart transplant recipients, pulmonary function was evaluated in 41 consecutive patients (mean age 43 years, range 15-57 years) before and 6 months after successful heart transplantation. The pulmonary function tests included measurements of forced vital capacity [FVC], forced expiratory volume in 1.s (FEV1), FEV1/FVC ratio, total lung capacity [TLC], and diffusion capacity for carbon monoxide [T(LCO)] and KCO [T(LCO) per l alveolar volume]. Compared to pretransplant values, spirometry after transplantation revealed modest improvements in FVC (from 77 ± 16 to 88 ± 21% of predicted [%pred]; p < 0.001) and FEV1 (from 75 ± 16 to 85 ± 22%pred; p < 0.001), whereas the FEV1/FVC ratio was unchanged (81% ± 11 and 80% ± 10; p = NS). A slight but statisticaIly significant increase in TLC (from 78 ± 15 to 86 ± 18%pred, p < 0.001) was also observed. Prior to transplantation the mean T(LCO) was 76 ± 17%pred; 7 of the patients had a T(LCO) below 60%pred (mean 51%pred). In 33 of the 41 patients a reduction in T(LCO) was observed after transplantation; for all 41 patients the mean fall in T(LCO) was 14% of the predicted value (SD 12%pred) (p < 0.0001). Likewise, a significant reduction in KCO was noted (p < 0.0001). Multiple regression analysis revealed that high pretransplant T(LCO)%pred (p = 0.02) and FVC%pred (p = 0.04) were associated with a less favorable outcome concerning posttransplant T(LCO)%pred. Although normalization of FEV1, FVC and TLC can be anticipated after correction of severe chronic left ventricular failure by heart transplantation, the pronounced concomitant decline in diffusion capacity observed in this study may be explained by underlying pulmonary disease caused by factors other than long-standing heart failure. Our findings support the notion that pulmonary function abnormalities attributable to chronic heart failure should not preclude consideration for heart transplantation.