Left Ventricular Concentric Remodeling In Deployed Post 9/11 Veterans And Effects On Exercise Performance.

Military personnel were deployed to regions characterized by high-levels of particulate matter air pollution and other deployment-related airborne hazards. Following deployment, a wide variety of respiratory symptoms and exercise intolerance have been reported though the etiology remains unresolved. Chronic low level air pollution is known to contribute to adverse left ventricle concentric remodeling (LVCR), which can affect cardiac function and therefore exercise tolerance. Whether LVCR is present and impacts exercise performance in previously deployed veterans with deployment exposures is presently unknown. PURPOSE: To identify the presence of LVCR in a non-treatment seeking sample of deployed post-9/11 veterans with airborne hazards exposure and determine its influence on cardiopulmonary exercise test (CPET) performance. METHODS: 45 deployed veterans (age: 39.6 ± 7.7, 41 M, 4F) without cardiovascular or respiratory diagnoses at the time of the study underwent transthoracic echocardiography and CPET. The presence of LVCR or hypertrophy was assessed and compared to a reference population with similar body mass and cardiovascular risk factors (Framingham Cohort). Mixed effects models were used to assess CPET differences (VO2/kg, VE/VCO2. PetCO2, VO2/HR, HR Recovery @ 1 minute, Pulse Pressure) between those with and without LVCR during exercise along with effect size calculations (d) at peak exercise. RESULTS: Rates of LVCR were much greater in our sample relative to reference population: 16% vs 6%, 35% vs 11%, 46% vs 16% in normal (n = 6), overweight (n = 26), and obese (n = 13) individuals respectively. 41 veterans had complete CPET data and those with LVCR had reduced exercise capacity and ventilatory efficiency (d = 0.42 – 0.47; p = 0.06 – 0.11) but similar HR recovery, Pulse Pressure and VO2/HR (d = 0.08 – 0.30, p = 0.30 – 0.80). CONCLUSIONS: Rates of LVCR in our sample of deployed veterans with airborne hazards exposure, but without cardio-vascular/pulmonary diagnoses, exceed that of a population based civilian sample. Those with LVCR have some evidence of CPET impairment but requires future investigation. This study suggests the need for greater research into the subclinical cardiovascular effects from deployment hazards that may precede the development of disease. VA CSR&D 1I01CX001515