Abstract
Introduction: Lung diffusion capacity for carbon monoxide (DLCO) impairment is often in IPAH patients (pts), and it can be profound in some of them.
Objectives: To assess the degree of DLCO impairment, its correlates with other parameters, and its prognostic significance in IPAH.
Methods: 65 IPAH pts (49 women and 16 men, median age 43 years) were allocated to one of two groups depending on DLCO% pred.value. Pts with DLCO<55% pred. were considered to have low DLCO and were compared to the remaining pts in regard to functional status and exercise capacity, lung function tests, hemodynamic parameters, and survival. DLCO<55% pred. showed 91% specificity, 27% sensitivity, 75% of PPV and 55% of NPV for death prediction in ROC analysis. Mann-Whitney U test and Fisher's chi-square test were used for comparison, data are presented as median values. P<0.5 was considered statistically significant.
Results: DLCO<55% pred. was found in 18% of pts. In comparison to pts with DLCO≥55% pred. they had:
more pronounced disturbances in breathing gas distribution: MMEF% pred. 44 vs 76 p=0.008, VA/TLC 0.8 vs 0.88 p=0.01;
higher proportion of WHO FC class III and IV: 75% vs 26% p=0.005;
shorter 6MWT distance: 284m vs 395m p=0.01, and lower minimal saturation during exercise: 82% vs. 94% p=0,0006.
There were no significant differences in hemodynamic profile. Low DLCO was a negative prognostic indicator for survival and carried a 4-fold increase of death risk in 5-year perspective (HR 3.9, 95%CI:1.8-8.6, p= 0.0006).
Conclusions: DLCO correlated well with functional but not hemodynamic parameters in IPAH. Low DLCO was associated with worse prognosis.
- Copyright ©ERS 2015