Bending Oxygen Saturation Index and Risk of Major Cardiac Adverse Events in Patients with Pulmonary Arterial Hypertension.

Abstract

Introduction: Shortness of breath while bending and its more objective version, bending oxygen saturation index (BOSI), are the latest additions to pulmonary arterial hypertension (PAH) symptom and signs armamentarium. In this study, we aimed to evaluate the association between BOSI and clinical outcomes in patients with PAH and to explore its potential to complement current risk estimation schemes.

Methods: In this single-center, prospective, observational study, we enrolled patients with PAH who are under stable treatment. Baseline mortality risk was estimated using established risk schemes. Primary endpoint was defined as the combination of all-cause hospitalization and all-cause mortality at 1 year. The discriminative performance of BOSI was evaluated using ROC curve analysis.

Results: A total of 102 patients were enrolled into the study. BOSI was equal to or more than 3 in 33 patients (32.4%). Primary endpoint occurred in 20 (60.6%) in BOSI ≥3 group and 16 (23.2%) in BOSI <3 group (p < 0.001). ROC analysis showed that BOSI had a significant discriminative ability (AUC 0.687, p = 0.002). Cox regression analysis showed that a BOSI ≥3 was significantly associated with adverse events, even after adjustment for baseline risk estimated by the four most used risk schemes (REVEAL, REVEAL Lite, COMPERA, and European Society of Cardiology/European Respiratory Society risk scores).

Conclusion: BOSI is independently associated with adverse events in patients with PAH and its addition to current risk scores may improve baseline risk estimation.