Variability in Blood Pressure Assessment in Patients Supported with HeartMate 3

Abstract

Targeted blood pressure (BP) control is a goal of LVAD medical management, but the interpretation of values obtained from automated cuffs and Doppler opening pressure (DOP) is challenging. The aim herein is to compare BP values obtained using arterial line (A-Line) and noninvasive measures in patients on HeartMate 3 support. In the MOMENTUM 3 Continued Access Protocol, paired BP values from A-Line and DOP (354 readings in 277 patients) and A-Line and automated cuff (296 readings in 256 patients) were obtained (>90% ≤7 days postop). Pearson (R) correlations between A-Line and cuff systolic blood pressure (SBP), mean arterial pressure (MAP), and DOP were assessed. A-Line and noninvasive BP measurements in the absence or presence of a palpable radial pulse (>1 in 5 seconds) were also compared. There were moderate correlations between A-Line SBP and DOP (R=0.63) and A-Line MAP and DOP (R=0.53) (Fig. A, B). DOP was 4±10 mmHg higher than A-Line MAP and 8±11 mmHg lower than A-Line SBP. When DOP was ≤90 mmHg, the mean absolute difference between DOP and A-Line MAP was 6 ± 6 mmHg compared to 10 ± 9 mmHg between DOP and A-Line SBP. At higher pressures, the disparity between DOP and A-Line MAP increased. The presence of a palpable pulse and high pulse pressure reduced DOP accuracy (Fig. C, D). With a palpable pulse, only 64% DOP values were within 10 mmHg of the A-Line MAP. The correlations between cuff SBP to A-line SBP and cuff MAP to A-Line MAP were poor (Fig. E, F, R=0.36-0.45), but the presence of a palpable pulse and high pulse pressure improved cuff accuracy (Fig. G,H). With a palpable pulse, 71% of cuff MAP values were within 10 mmHg of A-Line. On average, DOP is lower than A-Line SBP and higher than A-Line MAP. In patients with DOP ≤90 mmHg or without a radial pulse, it may be reasonable to interpret DOP as the MAP. The presence of a palpable pulse or high pulse pressure reduces DOP accuracy but improves cuff MAP accuracy. When DOP is >90 mmHg, DOP should not be interpreted as MAP; cuff measures may yield greater accuracy.