Continuous Blood Pressure Monitoring During Six-Minute Walk Test and the Hemodynamic Response in Patients with Pulmonary Hypertension

Introduction: The six-minute walk test (6MWT) is frequently performed in patients with pulmonary hypertension (PH) to assess exercise capacity. Systolic blood pressure (SBP) values and variation during 6MWT may hold prognostic significance, but technologic limitations have precluded routine measurement. We used a novel device for continuous SBP monitoring during 6MWT and analyzed the relationship with PH severity. Methods: Caretaker®, an FDA-approved wireless continuous noninvasive BP device that uses pulse decomposition analysis was worn during 6MWT in patients with and without PH. We compared SBP values before, during, and after 6MWT. A repeated-measures ANOVA was used to compare SBP between groups. Results: Of the 80 patients tested, fifty patients (62.5%) demonstrated adequate signal quality for SBP monitoring. SBP varied significantly with the 6MWT in the PH group (N = 26; before vs. during vs. after; 129.1 [18.7] vs. 126.7 [18.6] vs. 140.3 [23.5] mmHg, p = 0.0006), but not in the non-PH group (N = 24; 136.1 [17.6] vs. 137.8 [17.9] vs. 143.1 [20.0] mmHg, p = 0.16). In the PH group, SBP variation while walking was inversely correlated with baseline pulmonary artery systolic pressure (PASP) (R = -0.47, p = 0.039, Figure 1 ). Conclusions: Continuous, clinic based SBP monitoring was feasible in nearly two-thirds of patients undergoing 6MWT. SBP response during walking differed between patients with and without PH and may provide clinically relevant insight into a patients exercise response. In patients with PH, change in SBP during 6MWT was inversely correlated with baseline PASP, suggesting dysregulated exertional hemodynamic response in patients with severe PH.