The effects of bilateral lung transplantation on ventilatory efficiency, oxygen uptake and the right heart: a two-yr follow-up.

BACKGROUND

This study was to examine the course of ventilation/perfusion mismatch (VE/VCO(2)-slope) before and during two-yr follow-up after bilateral lung transplantation (BLTx) and to relate exercise parameters with the reverse right ventricular remodeling.

METHODS

We prospectively examined 20 patients (nine women; age 46.0 ± 13.0 yr) by cardiopulmonary exercise testing (before and at 3, 6, 12, and 24 months after BLTx), and by echocardiography and blood gas analysis. Etiology of pulmonary failure was chronic obstructive pulmonary disease as well (n = 8), pulmonary hypertension (n = 7), idiopathic fibrosis (n = 3), others (n = 2).

RESULTS

The VE/VCO(2)-slope before BLTx was 47.5 (interquartile range 24.5) and declined at 3 months -25.9%, 6 months -30.9%, 12 months -33.9%, and 24 months -35.1% (all p ≤ 0.003) and was then not different from normal. The right ventricular end diastolic diameter RVEDd narrowed from 35.0 (22.5) before to 31.0 (9.0) mm at 3 months after LTx. Similarly, right ventricular systolic pressure (RV(sys)) decreased from 53.6 ± 28.3 to 26.2 ± 5.2 mmHg (all p < 0.01). RVEDd correlated with VE/VCO(2)-slope before (p < 0.0001) but not after BLTx. PeakVO(2) increased from 10.0 ± 2.3 mL/min per kg before BLTx by 86.5% at 24 months (p < 0.01).

CONCLUSIONS

The functional status (VE/VCO(2)-slope, peakVO(2)) improves quickly after lung transplantation and is accompanied by reverse remodeling of the right heart. A correlation between exercise parameters and right heart function was found before BLTx only.