Background: Endothelium plays an important role in the development and progression of Pulmonary Arterial Hypertension (PAH), independently of its aetiology. Little is known on derived central blood pressure (CBP) and arterial stiffness in PAH. The aim of this study was to describe CBP and arterial stiffness as measured by PWA (Aix).

Methods: We studied 21 PAH patients; 11 were first diagnosis and not treated (PAHNT, age 58±17 yrs, BP 135±33/81±16 mmHg, direct PAPc 49±13 mmHg mean±SD); 10 were under specific drugs (Calcium channel blockers, endothelin receptor antagonists, phosphodiesterase type 5 inhibitors, prostacyclin derivatives) (PAHT, age 67±8 yrs, BP: 136±28/72 ±14 mmHg, PAPc, 42±14mmHg). 10 age and sex matched subjects served as controls (C, age 61±15 yrs, BP:130±13/77±6 mmHg). We used applanation tonometry (Sphygmocor, AtCor) to study PWA and to derive CBP and Aix, which was used as an index of arterial stiffness.

Results: Both systolic and diastolic CBP were similar in the three groups. On the contrary Aix was higher in PAH than in C (26 ± 7.8 vs. 19 ±11.6%); among the two PAH groups, Aix was significantly higher in NT than in T (30±6.9 vs. 22±7.1% p<0.02). In PAH Aix showed significant correlation (p<0.05) only with BMI (r=−0.49).

Conclusions: Our data show that AIx is increased in PAH. They also show that it decreases in association with specific therapy. This pilot study suggests that AIx could be used in PAH as an additional non-invasive marker to assess the efficacy of therapy.