The Obestiy Paradox: The Protective Effect of Obesity on Right Ventricular Function Using Echocardiographic Strain Imaging in Patients With Pulmonary Hypertension
BACKGROUND: Obesity is associated withright ventricular (RV) dysfunction, but its effect on RV remodeling in patients with pulmonary hypertension(PHTN) has not been studied. We evaluated the effect of obesity, and its interplay with diabetes, in patients with PHTN using RV echocardiographic strain imaging. METHODS: 185 patients underwent echocardiographic imaging and pulmonary artery pressure was calculated using tricuspid regurgitation jet velocity. From focused RV apical-four-chamber view, global and mid peak systolic RV free wall longitudinal strain (FWLS) wascalculated using speckle-tracking software. RESULTS: Global and mid RV FWLS in patients with PHTN (n=84) was lower (-16.8+/-7 vs -18.9+/-6.3, P=0.035 & -11.2+/-12.8 vs -18.9+/-9.2, P=0.002 respectively) compared with patients without PHTN (n=101). Among patients without PHTN, obese patients (BMI >30) had lower global and mid RV FWLS (-17.2+/-6.2 vs -20.3+/-5.7, P=0.012 & -17.6+/-7.2 vs -21.9+/-7.3, P=0.004), even after excluding diabetic patients (Mid RV FWLS -18.2+/-6.8 vs -22.1+/-8, P=0.032). Among patients with PHTN, obese patients had similar RV FWLS compared with non-obese patients (P=0.46). However, on excluding diabetic patients from PHTN group, obese patients with PHTN had higher global and mid RV FWLS (-21.7+/-5.7 vs -16.1+/-8, P=0.017 & -23.8+/-4.8 vs -17+/-9.4, P=0.009 respectively) compared to non-obese patients which suggests a protective effect of obesity on RV function in patients with PHTN. CONCLUSIONS: Obesity is associated with subclinical RV dysfunction as assessed by RV strain imaging, but paradoxically it may confer a protective effect on RV function once the patient develops PHTN. Future studies should evaluate the clinical impact of this paradox.
Patel, H., Bhutani, S., Posimreddy, S., Shah, P., Rampal, U., Gandhi, A., Vasudev, R., Pullatt, R., Virk, H., Shamoon, F., Bikkina, M., & Goldfarb, I. (2018). The Obestiy Paradox: The Protective Effect of Obesity on Right Ventricular Function Using Echocardiographic Strain Imaging in Patients With Pulmonary Hypertension. Minerva Cardioangiologica, 66 (5), 523-527. https://doi.org/10.23736/S0026-4725.18.04592-9