Pulmonary Hypertension Complicating Systemic Hypertension, Is Diastolic Dysfunction the Culprit?

Background: Elevation in PA pressures has been observed by 2D echo in some but not all hypertensive patients. The mechanism and hemodynamic impact of pulmonary hypertension in these patients remains unclear. Methods: We reviewed echoes of all patients referred with systemic hypertension between 9/2006 to 5/2009 to identify those patients with left ventricular hypertrophy, normal systolic function, and evidence of PH (i.e., systolic PA pressure (sPAP) >35 mmHg by echo). Patients with primary pulmonary disease, renal disease requiring dialysis, systolic dysfunction, valvular heart disease, and infiltrative cardiac disease were excluded from analysis. Quantitative measures of cardiac chamber size, and right and left ventricular hemodynamics were assessed in these patients (n=185) using standard methods, including calculation of diastolic PA pressure (dPAP) and mean PA pressure ([mPAP). LV remodeling was assessed with relative wall thickness (RWT), and diastolic function using mitral annular tissue Doppler (E/E). Results: Interestingly, sPAP correlated with left atrial area (R=0.18, p=0.03), while dPAP showed significant correlation to tissue Doppler septal E/E’(R=0.23, p<0.04). Right atrial area was associated with increases in mPAP (R=0.47, p<0.001), sPAP (R=0.19, p=0.02), and dPAP (R=0.25, p=004). In addition, mPAP was higher in patients with RWT ≥0.45 (37.37 mmHg vs 14.42, p=0.0013). Furthermore, a highly significant correlation was also observed between RWT and septal E/E’ (R=0.33, p<0.0001). Conclusions: In patients with systemic hypertension and evidence of PH, pulmonary pressure appears to be related to LV diastolic function as evidenced by both left atrial dilation and elevated diastolic filling pressure. This may be a consequence of the abnormal LV remodeling observed. These findings support a mechanism for development of PH in systemic hypertension. Moreover, the observed relation between pulmonary pressure and right atrial enlargement suggests important anatomic repercussions in this subset of patients.