Incidence and clinical impact of coronary artery disease confirmed by coronary CT angiography in patients with interstitial lung disease.

Background: Patients with interstitial lung disease (ILD) who undergo routine chest computed tomography (CT) often have findings suggestive of coronary artery disease (CAD). However, the incidence and prognostic impact of significant CAD, confirmed by coronary CT angiography (CCTA), are not well established.

Methods: From January 2013 to February 2024, we evaluated 215 patients from a retrospective ILD registry at our institute, who underwent CCTA as part of ILD management. Using the CAD-Reporting and Data System, we investigated the incidence of significant CAD and evaluated its impact on 5-year mortality and rehospitalization for respiratory or cardiovascular causes through multivariable Cox proportional hazards regression.

Results: During a median follow-up of 2.3 years, CCTA was performed at a median of 5 months postdiagnosis of ILD in the cohort. Significant CAD was identified in 92 patients (42.8%), with 27 (12.6%) undergoing coronary revascularization. The presence of significant CAD was significantly associated with an increased risk of mortality (adjusted hazard ratio [HR]: 2.31; 95% confidence interval [CI]: 1.07 - 5.01; P = 0.03) and a higher risk of rehospitalization (adjusted HR: 2.03; 95% CI: 1.23 - 3.34; P = 0.01). Key clinical variables associated with significant CAD included older age (≥ 63 years), hypertension, and coronary calcification observed on non-gated chest CT.

Conclusions: CCTA-identified CAD was associated with a worse clinical prognosis in patients with ILD, with significant risk factors including older age, hypertension, and coronary calcification observed on non-gated chest CT. These findings suggest that obtaining CCTA may be beneficial for managing patients with ILD, particularly those with identified risk factors.