PURPOSE: The association between obesity and pulmonary hypertension (PH) remains poorly defined. The purpose of our study was to ascertain the effect of Body Mass index (BMI) on pulmonary hemodynamics.
METHODS: We used a database of patients who underwent right heart catheterization (RHC) at a major tertiary care center between January 2002 and December 2006. PH was defined as mean pulmonary artery pressure (mPAP) >25mmHg. Three groups were analyzed on the basis of BMI 25–30; 30–35 and more than 35. Two way Analysis of Variance (ANOVA) was performed on the data using SPSS software. Tukey HSD was utilized for post-hoc multiple comparisons.
RESULTS: A total of 8254 patients suspected to have PH, underwent RHC during the specified study period. For the entire group, mean BMI was 28.4; mean Right Atrial (RA) Pressure was 9.09; the mean Pulmonary Capillary Wedge Pressure (PCWP) was 16.07; the mean Pulmonary arterial Pressure (mPAP) was 27.5 and the mean Pulmonary Vascular Resistance (PVR) was 2.56. After missing data for BMI and duplicate / triplicate procedures in each category were removed, approximately 1600 patients with PH were left for analysis. Except for PVR (F=1.46), all the variables mean RA pressure (F=10.52), PA Diastolic (F=9.96), mPAP (F=5.61), mean PCWP (F=4.49) and thermodilution cardiac output (TD CO; F=60.70) were significantly different when compared between groups. Results of the post-hoc multiple comparison are provided in Table 1. Mean RA pressure, PA Diastolic and mPAP were significantly different between group 1 and group 3. PCWP Mean was significantly different between group 1 and group 2. TD Co was significantly different among all three groups. Mean + standard error values with the significance are provided in figure 1.
CONCLUSION: Regardless of the underlying disease process(es) or the pathophysiologic attributes contributing to PH, mean RA pressure, mean PA diastolic, mean PCWP and mean cardiac output increase proportionately with increases in BMI.
CLINICAL IMPLICATIONS: Pulmonary Hypertension may be more severe in the morbidly obese and is usually of the mixed (arterial and venous) etiology.
DISCLOSURE: Roop Kaw, No Financial Disclosure Information; No Product/Research Disclosure Information