242 - Thoracic Impedance & Pulmonary Artery Pressure Monitoring in Prevention of Heart Failure Hospitalizations

Abstract

Introduction: According to 2006 estimates, there are over 5.1 million patients with heart failure in the United States, with the incidence expected to increase. Heart failure patients also account for over a million hospitalizations each year with up to a 24% readmission rate. New technologies such as thoracic impedance monitoring and pulmonary artery (PA) pressure monitoring have been developed to detect early heart failure exacerbation and prevent rehospitalizations. It is currently unknown whether one technology is superior to the other in preventing hospitalizations. Objective: Evaluate whether thoracic impedance and PA pressure correlate and predict heart failure hospitalizations. Methods: Patients with a CardioMEMs PA pressure sensor implanted at the time of euvolemia and a concurrent Medtronic Automatic Implantable Cardioverter Defibrillators with thoracic impedance (OptiVol) sensor were recruited from the Northwell Health North Shore University Hospital and Long Island Jewish Medical Center Heart Failure Clinics. Data was abstracted from the patients' devices and charts were reviewed for hospitalizations for heart failure. Analysis was then performed for overall correlation between the two modalities as well as in changes in each modality in the 14 days preceding the patients' hospitalizations for heart failure. Results: 15 patients with an average age of 65.7 years, predominantly men (80%), 67% of whom had ischemic cardiomyopathy and an average ejection fraction of 34% were recruited for the study. Over the average follow up period of 7.5 month, 7 patients had 11 hospitalizations for heart failure. There was only a weak negative correlation of −0.31 between all the available PA diastolic and thoracic impedance measurements. In the two weeks preceding each hospitalization, there was no clear pattern in changes in PA diastolic pressure or thoracic impedance that would allow for prediction of hospitalization. Conclusions: In a small cohort of heart failure patients, no significant changes in either PA diastolic pressures or thoracic impedance measurements preceded heart failure hospitalization events. Furthermore, no correlation between them was observed. This may be confounded by the lack of the variation in PA diastolic pressures during the follow-up period. Larger randomized trials are needed to evaluate which variables can predict heart failure hospitalizations.