Cardiopulmonary comorbidities are associated with hemodynamics in pulmonary arterial hypertension

Background: Cardiopulmonary comorbidities are risk factors for pulmonary hypertension (PH). However, in clinical practice it may be difficult to determine if they are coexisting comorbidities or represent an underlying cause for PH. Methods: We retrospectively analysed the cardiopulmonary comorbidities in patients undergoing right heart catheterization. Patients were divided into five groups according to their mean pulmonary arterial pressure (PAP) (<20mmHg: normal, 21-24mmHg: borderline-, 25-35mmHg: mild-, 36-48mmHg: moderate-, ≥49mmHg: severe PH). In-between group comparisons were performed by Kruskal-Wallis- and U-Tests. Results: 547 patients were included. The number of cardiopulmonary comorbidities was significantly associated to the PAP-groups (normal: 1.04±0.91 comorbidities, borderline: 1.66±1.07, mild: 2.06±1.10, moderate: 2.19±1.30, severe: 1.57±1.28), p=0.0001. Patients with no PH and those with severe PH had a significantly lower number of cardiopulmonary comorbidities as compared to those with mild- and moderate PH. Subgroup analysis of patients with pulmonary arterial hypertension (PAH) revealed significant differences between patients without PH and patients with borderline (p=0.0001) or mild PAH (p=0.006), but showed no difference between patients without PH and those with severe PAH (p=1.00). Conclusion: Patients with borderline, mild and moderate PH have significantly higher frequencies of cardiopulmonary comorbidities as compared to patients with normal PAP or severe PH. Accordingly, severe PH typically represents an isolated pulmonary vascular disease, while mild to moderate PH more often represents a pulmonary vascular manifestation of multi-organ disease.