A Real-World Study on Pulmonary Arterial Hypertension in Bulgaria: A Single-Center Retrospective Study From 2012 to 2022.

Purpose: This study aimed to analyze the epidemiological, clinical, and therapeutic characteristics of patients with pulmonary arterial hypertension (PAH) treated at a major reference center in Bulgaria and to assess treatment patterns, patient compliance, and overall survival. Principal Results: The epidemiological data revealed that 69.5% of the patients were female, with a mean age of 52 years. The majority of patients were diagnosed at advanced stages of PAH, with 92.1% classified as World Health Organization Functional Class III. Monotherapy was the most common treatment regimen, used by 61.4% of patients, despite advanced disease. Patients who adhered to treatment demonstrated significantly longer overall survival (78.9 months) compared to those lost to follow-up (50.8 months). The study also identified a 31% rate of noncompliance, with patients missing follow-up visits and becoming ineligible for further therapy. Major Conclusions: The findings highlight the need for earlier diagnosis and more aggressive treatment strategies, as monotherapy appears insufficient for optimal outcomes in advanced PAH. Establishing a national PAH registry and increasing disease awareness could facilitate earlier interventions and improve patient outcomes in Bulgaria.