Improved survival in limited scleroderma-related pulmonary artery hypertension

Utility of FVC/DLCO ratio to stratify the risk of mortality in unselected subjects with pulmonary hypertension

In patients with systemic sclerosis, a ratio between forced vital capacity (FVC) and diffusing capacity of carbon monoxide (DLCO, FCV%/DLCO%) >1.5 might be a predictor of pulmonary hypertension (PH). The aim of this study is, therefore, to evaluate whether this index can be used in patients with PH, regardless of etiology. 83 consecutive outpatients with suspected PH at non-invasive work-up underwent spirometry and DLCO test before right heart catheterization (RHC); FVC%/DLCO% ratio was then calculated and compared with mean pulmonary-artery-pressure (mPAP) and mortality at 5-year follow-up. Significant correlations between FVC%/DLCO% and PAsP and mPAP levels were found (p < 0.05). After ROC curve analysis and definition of best cut-off values for PAsP and FVC%/DLCO%, increased mPAP values at RHC were observed comparing subjects with both PAsP and FVC%/DLCO% values below cut off values (-/-), either PAsP or FVC%/DLCO% above cut off values (±), or both above (+/+) (p < 0.05). Poorer survival rates are observed at follow-up with higher FVC%/DLCO% values (0% for <1, 17.4% for 1-3, 33.3% for >3, p < 0.05), when comparing subjects with either increased PAsP and FVC%/DLCO% values or both with those with lower (log-rank p < 0.05). Even in subjects with mPAP at RHC >25 mmHg, increased FVC%/DLCO% values predicted a worse outcome (p < 0.05). FVC%/DLCO% values are related to mPAP in subjects with suspected PH, and may further stratify the risk of mortality in addition to PAP.

Survival protection by bodyweight in isolated scleroderma-related pulmonary artery hypertension

In chronic heart failure (CHF) due to systemic cardiovascular disease, obese patients have better survival. Bodyweight versus survival was analyzed post hoc in subjects with limited scleroderma (SSc) and isolated pulmonary artery hypertension (PAH), i.e. with CHF due to pulmonary vascular disease. Rheumatologists referred scleroderma subjects for evaluation, and PAH was ascertained by right heart catheterization (RHC). Forty-nine SSc-PAH subjects were stratified by body mass index (BMI): obese 7 (14.3 %), overweight 11 (22.4 %), normal weight 21 (42.9 %), and underweight 10 (20.4 %) for 24-month follow-up and pooled together for long-term 72-month follow-up. Survival was analyzed by Kaplan-Meier method. Multivariate Cox proportional hazards modeling helped to assess variables associated to survival. At 24 months (17 events), survival increases with BMI across four groups (logrank for trend P = 0.031). By Cox multivariate mortality, best model included: BMI (P = 0.043), low lung diffusion (DLco, P = 0.007), and reduced stroke volume index (SVI, P = 0.017). At 72 month (37 events), higher BMI values were associated with better survival but not significantly (P = 0.076). By multivariate modeling BMI did not enter any model, whereas low DLco entered all (P < 0.001). Also low SVI (P = 0.02) and low mixed venous saturation (SvO2, P = 0.009) were associated with the prognosis. From PAH diagnosis to final event, BMI had small (5.4 %), but significant decline (P < 0.001). This is ascribed to CHF progression, and may explain BMI predictive power weakening. The results suggest BMI decline should be contrasted, DLco is useful for screening and with SVI and SvO2 for assessing prognosis and treatment.