The Effect of Pulmonary Hypertension on Ventilatory Efficiency in Advanced Lung Disease

SESSION TITLE: Pulmonary Vascular Disease I SESSION TYPE: Original Investigation Poster PRESENTED ON: Wednesday, October 26, 2016 at 01:30 PM - 02:30 PM PURPOSE: Increased ventilatory response has been shown to be a prognostic factor in patients with pulmonary hypertension and chronic heart failure. The Ve/CO2 slope, a value determined by cardiopulmonary exercise testing (CPET) is elevated due to increased breathing rate and mechanical dead space. Our aim was determine the difference between Ve/VCO2 in patients with pulmonary hypertension (PH), interstitial lung disease (ILD) or a combination of both. METHODS: A total of 49 patients were considered for CPET based on their standard of care as well as 4 controls. Patients were categorized into PH, ILD, PH+ILD or control group. CPET was conducted on an electronically braked cycle ergometer (Ergoline 800s; SensorMedics, Yorba Linda, CA) using a SensorMedics Vmax229d system. Patients were asked to exercise until they no longer could due to dyspnea or muscle fatigue. Results were analyzed in accordance with ATS/ACCP Guidelines on Cardiopulmonary Exercise Testing. Two way analysis of variance (ANOVA), where PH (yes, no) and ILD (yes, no) were the factors that were used to examine the effect of those factors on each outcome. The interaction between PH and ILD was included in all models. RESULTS: There were a total of 19 patients in the PH group (54.3±15.3 years), 16 in the ILD group (65.9±10.0), 14 in the PH + ILD Group (66.3±10.8 years) and 4 controls (41.5±14.5 years). For all models, the interaction between PH and ILD was not significant, and was removed from the model. There was a significant effect of PH (p<0.0008) on the VE/VCO2 slope as compared to the controls. Patients with PH had higher VE/VCO2 actual than those without PH (mean 36.2 vs 26.7). There was no effect of ILD. CONCLUSIONS: Patients with PH, in the setting of ILD or without exhibited a higher VE/VCO2 actual. This may be attributed to the vascular pathology itself or diminished diffusion capacity of carbon monoxide that is commonly seen in PH patients. Further studies need to be conducted to determine the exact mechanism in which PH effects VE/VCO2. CLINICAL IMPLICATIONS: The ventilatory efficiency parameters are easily measurable and highly reproducible parameters obtained from CPET. Thus, the rational risk stratification should include various parameters such as Peak VO2 and ventilatory efficiency parameters, particular measurement of VE/VCO2 slope with PH and ILD. DISCLOSURE: The following authors have nothing to disclose: Asma Iftikhar, Sonu Sahni, Nina Kohn, Sameer Verma, Edmund Miller, Arunabh Talwar No Product/Research Disclosure Information