Validity of pulse-transit-time based blood pressure measurements in patients with and without heart failure across different breathing maneuvers

Purpose: Using pulse transit time (PTT) and an ECG has been declared a promising alternative for invasive or noninvasive monitoring of blood pressure (BP). This study assessed the validity of PTT for BP monitoring in different subsets of patients under sleep laboratory like conditions. Methods: Ten healthy volunteers (HV; 7 male, 55.8±19.6 years), twelve patients with systolic heart failure (HF; 10 male, 67.3 ± 8.6 years, LVEF  37.9±11.8%) and fourteen patients with pulmonary arterial hypertension (PAH; 5 male, 59.5±13.4 years) performed different breathing patterns designed to simulate nocturnal sleep disordered breathing (SDB). BP was measured using two devices (oscillometrically via Task Force Monitor™, CNSystems and PTT via SOMNOscreen™, Somnomedics) at least every 15 minutes for 30 minutes before, during and after different breathing maneuvers. Results: Mean systolic BP was 111.3±15.1 mmHg vs. 110.0±14.7 mmHg for oscillometric method vs PTT, respectively. Corresponding values for diastolic BP were 69.9±12.2 mmHg and 69.9±14.2 mmHg. The two methods were hence neither clinically nor statistically (p>0.05) significantly different. Conclusions: When monitoring BP in patients without HF, with HF and with PAH, overall BP monitoring using PTT is comparable to oscillometry for a period of 1.5 hours (including a 0.5 hours SDB phase).