Validity of transit time-based blood pressure measurements in patients with and without heart failure or pulmonary arterial hypertension across different breathing maneuvers.

Pulse transit time (PTT) derived by ECG and plethysmographic signal can be a promising alternative to invasive or oscillometry-based blood pressure (BP) monitoring in sleep laboratories because it does not cause arousals from sleep. Therefore, this study assessed the validity of PTT for BP monitoring under sleep laboratory-like conditions. Ten volunteers (55.8 ± 19.6 years), 12 patients with heart failure with reduced ejection fraction (HFrEF; 67.3 ± 8.6 years), and 14 patients with Nizza class I pulmonary arterial hypertension (PAH; 59.5 ± 13.4 years) performed different breathing patterns to simulate nocturnal sleep-disordered breathing (SDB). BP was measured at least every 15 min over 1 h using oscillometry (Task Force Monitor™) and PTT (SOMNOscreen™) devices in free breathing conditions and during SDB simulation (alternating phases of hyperventilation and apneas). One hundred forty-two points of measurements were collected. No difference was found in both mean systolic BP (SBP) and diastolic BP (DBP) between oscillometric PTT-based BP measurements in the whole population and throughout the whole recording (SBP 111.3 ± 15.1 mmHg versus 110.0 ± 14.7 mmHg, p = 0.051; DBP 69.9 ± 12.2 versus 69.9 ± 14.2 mmHg, p = 0.701). Likewise, no significant difference in SBP and DBP was found between the two methods in the subgroups of healthy subjects, HFrEF patients and PAH patients, both in free breathing conditions (p > 0.05) and during SDB simulation (p > 0.05). When monitoring BP in healthy subjects, and in patients with HFrEF or PAH, PTT provides a BP estimation comparable with oscillometric measurement, though slightly inaccurate, both in the condition of regular and unstable breathing.