Demographics, BMPR2 status and outcomes in Distal Chronic Thromboembolic Pulmonary Hypertension

Abstract

Rationale Although pulmonary endarterectomy (PEA) is potentially curative in Chronic Thromboembolic Pulmonary Hypertension (CTEPH), some patients have distally distributed disease that is not amenable to surgery. The aetiology and characteristics of this patient group are currently not well understood.

Objectives This study compares the baseline demographics and outcomes of subjects with distal CTEPH, proximal CTEPH and Idiopathic Pulmonary Arterial Hypertension (IPAH). This will help determine whether these conditions represent separate entities, or whether they in fact exist along the same spectrum of disease.

Methods The medical history, clinical characteristics, Bone Morphogenetic Receptor type 2 (BMPR2) mutation status and outcomes of 96 IPAH, 35 distal CTEPH and 68 proximal CTEPH subjects referred to a single specialist centre between 1994 and 2005 were reviewed.

Results There were significant differences between the distal CTEPH, proximal CTEPH and IPAH groups in age (55.9yrs vs 54.8yrs vs 46.2yrs p<0.0001), proportion who were male (43% vs 69% vs 29% p<0.0001), previous Deep Vein Thrombosis (28.6% vs 30.9% vs 3.1% p<0.0001), positive BMPR2 status (0% vs 0% vs 15% p=0.018), mean Pulmonary Artery Pressure (47.3mmHg vs 45.4mmHg vs 54.8mmHg p<0.0001) and Total Pulmonary Resistance (12.9WU vs 12.4WU vs 18.1WU p<0.0001). Both distal CTEPH and IPAH subjects were managed similarly, and had comparable survival characteristics (77% 1yr, 53% 3yrs vs 86% 1yr, 60% 3yrs p=0.68).

Conclusions Distal and proximal CTEPH groups share certain demographic features that not only indicate a common aetiology but also help differentiate them from IPAH patients. Despite more favourable haemodynamic parameters in the distal CTEPH group, subjects displayed a poor long term outcome similar to that of IPAH subjects.