Frequency of Echocardiographic Evidence Suggestive of Pulmonary Hypertension in Patients with Interstitial Lung Disease: A Retrospective Study at a Tertiary Care Hospital in Karachi, Pakistan

Objectives: To determine the frequency of echocardiographic evidence suggestive of pulmonary hypertension (PH) among patients with interstitial lung disease (ILD), assess its distribution across ILD subtypes, and compare clinical characteristics, pulmonary function parameters, cardiac function, and one-year mortality between patients with and without elevated estimated pulmonary artery systolic pressure (ePASP). Methodology: This retrospective observational study included 200 adult patients with confirmed ILD attending the outpatient ILD clinic at Aga Khan University Hospital, Karachi, between January and December 2023. ILD was diagnosed using high-resolution computed tomography and/or histopathological findings. Echocardiographic evidence suggestive of PH was defined as ePASP >30 mmHg, based on echocardiographic examinations performed within one year of the index ILD assessment. Patients were categorized into ILD with elevated ePASP and ILD without elevated ePASP groups. Results: Of the 200 patients, 80 (40.0%) demonstrated elevated ePASP suggestive of PH, while 120 (60.0%) had no elevated ePASP. The mean age was 63.04 ± 13.84 years, and 134 patients (67.0%) were female. Among patients with elevated ePASP, 28 (35.0%) had mild, 32 (40.0%) had moderate, and 20 (25.0%) had severe elevation. The highest within-subtype frequency of elevated ePASP was observed in idiopathic pulmonary fibrosis (IPF; 56.5%), followed by sarcoidosis (54.5%) and nonspecific interstitial pneumonia (NSIP; 52.9%). Patients with elevated ePASP had significantly lower forced expiratory volume in one second (FEV₁) than those without elevated ePASP (1.31 ± 0.47 versus 1.55 ± 0.79 L; p = 0.017). Right ventricular systolic dysfunction was more frequent in the elevated-ePASP group (19.5% versus 1.0%; p <0.0001). One-year mortality was significantly higher among patients with elevated ePASP compared with those without elevated ePASP (28.75% versus 10.0%; p = 0.001). Conclusion: Elevated ePASP suggestive of PH was identified in 40.0% of patients with ILD, with the highest within-subtype frequencies observed among those with IPF, sarcoidosis, and NSIP. Elevated ePASP was associated with impaired right ventricular systolic function and higher one-year mortality.