Cardiothoracic Ratio and Aortic Knob Diameter in Immunocompromised Patients with Pulmonary Infections

Pulmonary infections in immunocompromised patients (ICPs) are a major cause of morbidity and mortality, often accompanied by cardiovascular changes. This study assessed the association between pulmonary infections and cardiovascular response, using cardiothoracic ratio (CTR) and aortic knob diameter (AKD) as indicators, in ICPs. A retrospective cross-sectional analysis was conducted on 105 posterior–anterior chest radiographs from ICPs with confirmed pulmonary infections. Transverse cardiac diameter (TCD), transverse thoracic diameter (TTD), CTR, and AKD were measured using standard radiographic techniques. Descriptive statistics, independent t tests, and regression analyses were performed. Mean TCD and TTD were 17.05 ± 2.50 cm and 34.06 ± 4.60 cm, respectively, with a mean CTR of 0.500 ± 0.05. Mean AKD was 4.58 ± 0.66 cm. CTR was significantly higher in ICPs compared to immunocompetent controls (p = .007), and AKD was also significantly elevated (p = .05). Regression analysis demonstrated a strong positive relationship between CTR, AKD, and age (R² = .659, p < .001). These findings suggest that pulmonary infections in ICPs are associated with measurable increases in cardiac size and aortic knob diameter. Routine chest radiography can therefore serve as a valuable, low-cost tool for early detection of cardiovascular changes in this vulnerable population, potentially guiding timely intervention and improving outcomes. Further research with larger cohorts and longitudinal follow-up is recommended to confirm causality and refine screening protocols.