Respiratory event-related pulse transit time drop rate predicts left ventricular impairment in obstructive sleep apnea.

OBJECTIVES

Pulse transit time (PTT) is used to assess vascular elasticity. We aim to investigate whether respiratory event-related PTT metrics can predict left ventricular (LV) impairment in obstructive sleep apnea (OSA).

METHODS

This retrospective study included OSA patients without pre-existing LV impairment who underwent polysomnography from January 2014 to May 2017 at Affiliated Huai'an No.1 People's Hospital and The First Affiliated Hospital of Nanjing Medical University. LV impairment was assessed via echocardiography and blood tests from December 2023 to May 2024. Respiratory event-related PTT metrics (drop rate, magnitude, index, nadir, area) were measured using SOMNOscreen + polysomnographic system. Cox models estimated hazard ratios for LV impairment, and receiver operating characteristic (ROC) curves assessed the predictive value.

RESULTS

The sample included 517 individuals (82.8 % male) with a median age of 53.0 years (IQR: 43.0-63.0). Over a median follow-up of 8.3 years, 112 patients (21.7 %) were diagnosed with LV hypertrophy (LVH) and 249 (48.2 %) with LV diastolic dysfunction (LVDD), none had systolic dysfunction. Patients in the fourth quartile of the PTT drop rate had adjusted hazard ratios of 2.49 [95 % CI, 1.38-4.49] for LVH and 3.84 [95 % CI, 2.49-5.92] for LVDD, and 0.53 ng/ml [95 % CI, 0.33-0.73] higher cardiac troponin T than those in the first quartile. No consistent associations were found with other PTT metrics. In ROC analysis, the PTT drop rate showed greater accuracy than traditional metrics in predicting LVDD.

CONCLUSIONS

A high respiratory event-related PTT drop rate, reflecting vascular hyperactivity, may help stratify LV impairment risk in OSA.