Pulmonary Hemodynamics in Systemic Hypertension

We reviewed cardiac catheterization data and the medical records of 30 patients with systemic hypertension to establish their pulmonary hemodynamic profiles and the relationship between certain clinical and demographic variables and increased pulmonary vascular resistance. Mean systemic arterial pressure ranged from 110 to 210 mm Hg, and systemic vascular resistance ranged from 17.6 to 47.0 units. Seven patients had normal pulmonary wedge pressure and normal pulmonary vascular resistance, one had elevated pulmonary wedge pressure and normal pulmonary vascular resistance, five had elevated pulmonary wedge pressure and increased pulmonary vascular resistance, and 17 had normal pulmonary wedge pressure and increased pulmonary vascular resistance. There were significant positive correlations between systemic vascular resistance and pulmonary vascular resistance and between mean systemic arterial pressure and mean pulmonary artery pressure, but there was no correlation between mean pulmonary wedge pressure and pulmonary vascular resistance. Of the 17 patients with normal pulmonary wedge pressure and increased pulmonary vascular resistance, seven had clinical or radiologic evidence of prior left ventricular failure. We conclude that increased pulmonary vascular resistance occurs commonly in patients with systemic hypertension. Although some cases of increased pulmonary vascular resistance relate to active or preexistent left ventricular failure, the majority remain unexplained, suggesting that neurohumoral or other factors may produce a hypertensive response in both the systemic and pulmonary arterial circuit.