1334 Peripheral Arterial Tonometry Sleep Testing in a Patient with Left Ventricular and Right Ventricular Assist Devices

Abstract Introduction Patients with reduced left ventricular ejection fraction (HFrEF) are at elevated risk for central and obstructive sleep apnea (OSA). We describe a case illustrating the use of peripheral arterial tonometry (PAT)-based sleep testing in a hospitalized patient with end-stage heart failure supported by both left and right ventricular assist devices (LVAD and RVAD), raising important considerations regarding the diagnostic performance and limitations of PAT technology in individuals with continuous-flow mechanical circulatory support. Report of case(s) A 40-year-old male (BMI 35.9 kg/m2) with nonischemic cardiomyopathy, HFrEF (EF 25-30%), atrial fibrillation, obesity, and previously diagnosed severe OSA but not on positive airway pressure (PAP) therapy was admitted with decompensated end-stage heart failure. He underwent LVAD implantation, which was complicated by right ventricular failure necessitating RVAD placement. During his hospital course, apneas during sleep were witnessed, prompting further evaluation for sleep-disordered breathing. Given the inability to undergo in-laboratory polysomnography, portable sleep assessments using PAT-based devices were implemented. Sleep testing was first attempted with the WatchPAT 300® while supported by both an LVAD and RVAD and on empiric bi-level PAP (BPAP 12/8 cm H₂O). The initial test was nondiagnostic due to improper positioning of the finger probe. A second night study was performed, which was also inconclusive, demonstrating an attenuated PAT signal. After several weeks, the patient’s RVAD was successfully removed, leaving him supported solely by an LVAD. Two SomFit® sleep studies using a forehead-mounted sensor were performed, first while on supplemental oxygen at 2 L/minute and the second while on room air. These studies also remained non-diagnostic due to minimal PAT signal amplitude, presumed again to be secondary to the patient’s low pulsatility index and altered hemodynamic profile under continuous-flow LVAD support. Conclusion Peripheral arterial tonometry reliability is limited in LVAD/RVAD patients because continuous-flow support reduces pulsatility and blunts autonomic responses, impairing sleep staging and detection of respiratory-related vascular changes. Altered preload, impaired baroreflex function, and poor peripheral perfusion can distort PAT signals, leading to under-recognition or misclassification of sleep-disordered breathing events. As a result, PAT-derived apnea metrics should be interpreted cautiously, and formal polysomnography remains the preferred diagnostic modality in this population. Support (if any)