Right Atrial/Pulmonary Arterial Wedge Pressure Ratio in Primary and Mixed Constrictive Pericarditis

Cardiac filling pressures may be elevated due to abnormalities in the myocardium, heightened pericardial restraint, or both. The authors hypothesized that the relative contributions due to myocardium and pericardium could be estimated by the ratio between right atrial pressure and pulmonary arterial wedge pressure (RAP/PAWP), which would enable better discrimination of the extent of myocardial disease in patients with constrictive pericarditis (CP).

This study investigated the relationships between RAP/PAWP and the pericardial thickness as well as echocardiographic parameters of myocardial function and assessed the prognostic implications of RAP/PAWP for long-term mortality in primary and mixed CP patients who underwent pericardiectomy.

A total of 113 surgically confirmed CP patients who underwent echocardiography and cardiac catheterization within 7 days of each other between 2005 and 2013 were included in the study. The patients were classified into a high RAP/PAWP group (≥0.77; n = 56) or a low RAP/PAWP group (<0.77; n = 57) according to the median RAP/PAWP value. The primary outcome was prognostic implication of RAP/PAWP on long-term mortality and assessment of the relationship between RAP/PAWP and Doppler echocardiographic parameters in primary and mixed CP. In addition, the relationship between RAP/PAWP and the pericardial thickness was assessed.

RAP/PAWP was directly correlated with pericardial thickness (regression coefficient [β] = 8.34; p < 0.001). RAP/PAWP had a significant direct correlation with early diastolic velocity of medial mitral annulus (e') (β = 10.69; p < 0.001) and inverse relationship with early transmitral diastolic velocity (E) (β = -105.15; p < 0.001), resulting in an inverse relationship with the ratio of E/e' (β = -23.53; p < 0.001). Patients with high RAP/PAWP ratio had a better survival rate compared with those with low RAP/PAWP ratio (p = 0.01). Its prognostic value was significant in primary CP (p = 0.03) but not in mixed CP with concomitant myocardial disease (p = 0.89).

The RAP/PAWP ratio can reflect the degree of pericardial restraint versus restrictive myocardium and was associated with the long-term survival after pericardiectomy.