Chronic Thromboembolic and Pulmonary Arterial Hypertension Share Acute Vasoreactivity Properties: Testing Protocol

Chronic Thromboembolic and Pulmonary Arterial Hypertension Share Acute Vasoreactivity Properties: Testing ProtocolPulmonary and systemic arterial pressures and the right atrial pressure (RAP) were continuously recorded, and the pulmonary artery occlusion pressure (PAOP) was recorded intermittently. The cardiac output (CO) was assessed by thermodilution (Cardiac Output Computer; Baxter/Edwards). The cardiac index (CI) was calculated as CO divided by the body surface area. PVR and systemic vascular resistance (SVR) were calculated according to the following standard formulas: PVR = (MPAP — PAOP) X 80/ CO); and SVR = (MAP — RAP) X 80/CO). The PP was calculated as the difference between systolic and diastolic pressure, and the fractional PP was calculated by dividing PP by MPAP. Arterial and mixed-venous blood samples were drawn simultaneously and were analyzed for arterial oxygen saturation (Sao2) with a blood gas analyzer (model 865; Chiron; Emeryville, CA) that was automatically calibrated every hour. buy glucophage
After insertion of the catheter, the hemodynamics were measured until stable baseline values were obtained (ie, < 10% variation within measurements for at least 15 min). Thereafter, patients were instructed to inhale iNO at a dose of 40 ppm via a tightly fitting facial mask without additional oxygen. Complete hemodynamic measures were obtained after 10 min while the patient kept inhaling. After an iNO washout period of at least 15 min and the return of hemodynamic values to baseline (< 10% variation to baseline), the patients inhaled 10 |j,g of iloprost (Ilomedin; Schering AG; Berlin, Germany) using an inhaler (Optineb; Nebu-Tec; Elsenfeld, Germany), and complete hemodynamic measures obtained 30 min later.
All results are expressed as the median and interquartile range. A statistical software package (SPSS, version 12.0.1; SPSS; Chicago, IL) was used for the statistical analyses. For comparisons between patients groups and within single patients the Mann-Whitney U test and the Wilcoxon matched pair test were used as appropriate. To compare vasoreactivity test responders with nonresponders, the Pearson x2 test was used. For correlations between responses to iNO and iILO, the Pearson correlation coefficient was calculated. A p value of < 0.05 was considered to be statistical significant.

This entry was posted in Respiratory Symptoms and tagged chronic thromboembolic pulmonary hypertension, pulmonary arterial hypertension, pulmonary hemodynamics, pulmonary vascular compliance, vasoreactivity testing.