[Effect of diazoxide on severe pulmonary hypertension]

Hemodynamic effects were studied after the administration of incremental doses of diazoxide (upper range 300-600 mg) in a group of 15 patients with severe pulmonary hypertension due to different etiologies. No significant changes were found in the mean pulmonary arterial pressure (PAP), "wedge" pressure, right atrial pressure, and right ventricular systolic work index (RVSWI). Significant decreases were found in the mean systemic arterial pressure, pulmonary arterial resistance (PAR), systemic arterial resistance (SAR) and left ventricular systolic work index (LVSWI). Significant increments were found in the cardiac output (Q), heart rate and PAR/SAR ratios (Table 1). A significant correlation was found between Q and SAR pretreatment (r = -0.75, p less than 0.002); PAR and SAR pretreatment (r = 0.69, p less than (0.01); change in SAR vs change in Q produced by diazoxide (r = -0.81, p 0.001); basal PAR/SAR vs D PAP (change pre-post diazoxide) (r = -0.58, p less than 0.05); % PAR/SAR vs % PAP (percent changes in PAR/SAR post diazoxide vs percent change of PAP post diazoxide) (r = 0.78, p less than 0.001); D PAP vs D RVSWI (PAP change post diazoxide vs RVSWI change post diazoxide) r = 0.79, p less than 0.001. No significant correlation (either in absolute or in percent values) was found between basal values of pulmonary artery pressure, cardiac output, pulmonary arterial resistance or right ventricular systolic work index vs those produced by the drug in the same parameters. Patients were divided into two groups according to the decrease or increase of pulmonary arterial pressure after diazoxide administration (n = 7 and 8, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)