Pulmonary function vascular index predicts prognosis in idiopathic interstitial pneumonia

• Published in: Respirology (Carlton, Vic.) Vic.), 2012-05, Vol.17 (4), p.674-680
• Main Authors: CORTE, TAMERA J., WORT, STEPHEN J., MACDONALD, PETER S., EDEY, ANTHONY, HANSELL, DAVID M., RENZONI, ELISABETTA, MAHER, TOBY M., NICHOLSON, ANDREW G., BANDULA, STEVEN, BRESSER, PAUL, WELLS, ATHOL U.
• Format: Article
• Language: English
• Subjects: Aged; Female; Fibrosis; forced vital capacity; Humans; idiopathic interstitial pneumonia; Idiopathic Interstitial Pneumonias - mortality; Idiopathic Interstitial Pneumonias - pathology; Idiopathic Interstitial Pneumonias - physiopathology; Kaplan-Meier Estimate; KCO; Male; Middle Aged; Prognosis; Pulmonary Diffusing Capacity; Pulmonary Emphysema - physiopathology; pulmonary hypertension; Respiratory Function Tests; Tomography, X-Ray Computed
• ISSN: 1323-7799; 1440-1843
• DOI: 10.1111/j.1440-1843.2011.02121.x

ABSTRACT Background and objective:  Pulmonary hypertension (PH) is associated with increased mortality in fibrotic idiopathic interstitial pneumonia (IIP). We hypothesize that baseline KCO (diffusing capacity of carbon monoxide/alveolar volume) and 6‐month decline in KCO reflect PH, thus predicting mortality in IIP. Methods:  All IIP referrals (2004–2007) were identified (n = 269). 192 had pulmonary function at 6 months. Fifty‐two (27%) died during follow‐up (median 22.5 months). Outcome was evaluated for early (1 year from 6‐month pulmonary function) and overall mortality. A vascular index best predicting mortality was identified (using baseline and 6‐month decline in KCO) and evaluated against PH at echocardiography. Results:  Baseline and 6‐month decline in KCO were associated with early and overall mortality. A positive vascular index (baseline KCO% ≤ 50% and/or ≥15% decline in KCO at 6 months; n = 40) was strongly predictive of early and overall mortality. Neither a diagnosis of idiopathic pulmonary fibrosis nor PH predicted early death when incorporated into this model. In patients without baseline PH, with follow‐up echocardiography (n = 60), a positive vascular index was associated with PH at follow‐up. Conclusions:  A vascular index comprised of baseline and 6‐month decline in KCO strongly predicted increased mortality and development of PH on echocardiography. In, KCO may be an important marker for pulmonary vascular disease and its associated mortality. In patients with idiopathic interstitial pneumonia, baseline KCO (diffusing capacity adjusted for VA) and 6‐month decline in KCO are both associated with increased early and overall mortality and, in a subgroup of patients with follow‐up echocardiography, are associated with the development of pulmonary hypertension at follow‐up.