Pulmonary Abnormalities, Diastolic Dysfunction, and World Trade Center Exposure: Implications for Diagnosis and Treatment

Serious illness and injury following the September 11, 2001 (9/11) attacks on the World Trade Center (WTC) affects thousands of responders who worked on the WTC rescue and recovery effort. During this time, these individuals sustained exposure to a vast array of environmental toxins and physical hazards. The population of survivors presents a unique opportunity to rigorously examine the effects of inhaled particulate matter on risk of persistent pulmonary and chronic cardiopulmonary disease.

Original reports of 9,500 WTC responders examined between July 2002 and April 2004, noted abnormal pulmonary function results in one-third of participants. Further studies of this population have demonstrated persistent changes in pulmonary function tests 9 years after exposure (2010 Annual Report on 9/11 Health). Numerous complex interactions between pulmonary and cardiovascular systems exist. In fact, at the molecular level, evidence supports an integral role for reactive oxygen species (ROS)-dependent pathways in the instigation of pulmonary oxidative stress, systemic pro-inflammatory responses, vascular dysfunction and atherosclerosis.

Studies in animals have shown that inhalation of particles can lead to weakening of the heart muscle. In addition, patients who have developed pulmonary disease from inhalation of particulate matter may develop increased pressures in the pulmonary arteries, as well as dysfunction of the right ventricle of the heart. Finally, patients who have suffered blockage of the coronary arteries may exhibit abnormalities in the heart function that may be detected by an echocardiogram.

Preliminary work by our group revealed echocardiographic evidence of cardiac abnormalities in a subset of 1190 WTC responders. Diastolic dysfunction, or impaired ventricular relaxation, is known to accompany aging and is associated with hypertensive heart disease. In our analysis of subjects < 50 years of age, BMI < 30, and lacking a diagnosis of hypertension, the investigators found a prevalence of diastolic dysfunction of 47%. Importantly, when the population was narrowed to exclude former or current smokers, and those with LV abnormalities, 12% had abnormalities of RV diastolic function. The investigators propose to analyze the relationship between pulmonary function abnormalities and evidence of diastolic dysfunction.

Persuasive data implicates obstructive sleep apnea (OSA) in the development of hypertension, arrhythmias, vascular dysfunction and cardiac disease. Webber et al demonstrated an increased prevalence of obstructive sleep apnea (OSA) among firefighters exposed to the WTC disaster, and our group has demonstrated a similar prevalence of screen positive for OSA among 2500 law enforcement officers present at Ground Zero. The relationship between OSA and risk of cardiac disease involves similar pathophysiologic pathways including inflammation and impaired vascular reactivity.