Evaluation of enhanced external counterpulsation with different modes on acute hemodynamic effects

Abstract

Objective: Enhanced external counterpulsation (EECP) is a noninvasive device for the treatment of cardiovascular diseases. However, there are minimal data regarding the effects of different EECP modes on acute hemodynamic changes, particularly blood flow redistribution. This study aimed to investigate the systemic hemodynamic effects during different EECP modes based on clinical trials and numerical analysis.

Methods: Fifteen patients with cardiovascular disease and 15 healthy subjects completed four and six EECP modes, respectively. These EECP modes changed the parameters, including counterpulsation pressure, start time, and counterpulsation frequency. Hemodynamic parameters in the aorta (AO), right femoral artery (RF), and right brachial artery (RB), including mean flow rate (FR), mean blood velocity (MV), peak systolic velocity (PSV), minimum diastolic velocity (MDV), and diastolic/systolic blood pressure ratio (D/S), were measured during EECP treatments. Meanwhile, the simulation of hemodynamic responses to different EECP modes based on a 0D-1D cardiovascular system model were conducted and compared with the clinical results.

Results: As counterpulsation pressure increased, the FR and PSV of AO, the FR, MV, PSV, and MDV of RF, the FR, MV, and MDV of RB, and D/S increased in patients (all P < 0.05). The MV of RF, the FR, MV, PSV, and MDV of RB, and D/S of patients decreased significantly with increasing start time (all P < 0.05). For the increase of counterpulsation frequency, the FR, MV, and PSV of AO, the MV, PSV, and MDV of RF, and the FR and MV of RB significantly decreased in patients (all P < 0.05). For the health group, most patients' results were similar. Multiple groups of pressure experiments indicated that 25-30 kPa significantly improved blood flow. The numerical results under different EECP modes were generally closely aligned with clinical measurements.

Conclusion: Different EECP modes induced different hemodynamic responses. Higher counterpulsation pressure, T wave start time, and 1:1 counterpulsation frequency are recommended to improve blood flow. Hemodynamic simulations prepare the way for the creation of virtual databases to obtain population-based strategies and then allow for precision-based strategies through individual modeling. The different hemodynamic responses to EECP modes provide theoretical guidance for the development of a patient-specific treatment strategy.

Keywords: 0D–1D cardiovascular system model; blood flow; cardiovascular disease; enhanced external counterpulsation; hemodynamic effects.

FIGURE 1

Process of converting ultrasonic images into flow rates and experiment sequence of EECP. Ultrasound images of (A) aorta; (B) right brachial artery; (C) right femoral artery; (D) diameter of arteries; (E) using Getdata software to trace the spectrum of blood flow velocity; (F) blood flow waveform after smoothing; (G) flowchart of the whole experimental scheme (assuming a cardiac cycle duration of 0.8 s).

FIGURE 2

(A) Structure of the closed-loop 0D-1D model of the cardiovascular system. (B) EECP model coupled with 0D-1D hemodynamic model.

FIGURE 3

FR, MV, PSV, and MDV ratio of EECP-P20 (20 kPa, T wave, 1:1) and EECP-P30 (30 kPa, T wave, 1:1) of AO (A), RF (B), and RB (C) in the patient group. Results were evaluated by the paired-sample t-test.

FIGURE 4

FR, MV, PSV, and MDV ratio of EECP-P30 (30 kPa, T wave, 1:1) and EECP-Time (30 kPa, T wave + 0.2 T, 1:1) of AO (A), RF (B), and RB (C) in the patient group. Results were evaluated by paired-sample t-test.

FIGURE 5

FR, MV, PSV, and MDV ratio of EECP-P30 (30 kPa, T wave, 1:1) and EECP-Freq (30 kPa, T wave, 1:2) of AO (A), RF (B), and RB (C) in the patient group. Results were evaluated by paired-sample t-test.

FIGURE 6

D/S value of EECP-P30 (30 kPa, T wave, 1:1) vs. EECP-P20 (20 kPa, T wave, 1:1) (A), vs. EECP-Time (30 kPa, T wave +0.2T, 1:1) (B), and vs. EECP-Freq (30 kPa, T wave, 1:2) (C) in patient group. Results were evaluated by paired-sample t-test.

FIGURE 7

Comparison of ratio of FR (A), MV (B), PSV (C), MDV (D) in the AO between the patient and healthy groups, *P < 0.05 EECP-P30 vs another EECP state, **P < 0.01 EECP-P30 vs another EECP state, ***P < 0.001 EECP-P30 vs. another EECP state. Results were evaluated by repeated-measures ANOVA (among 4 modes) by independent samples t-test (among two groups).

FIGURE 8

Comparison of the ratio of FR (A), MV (B), PSV (C), MDV (D) in the RF between the patient and healthy group, *P < 0.05 EECP-P30 vs another EECP state, **P < 0.01 EECP-P30 vs another EECP state, ***P < 0.001 EECP-P30 vs. another EECP state, ⁺ P < 0.05 CAD vs Healthy, ⁺⁺ P < 0.01 CAD vs. Healthy, ⁺⁺⁺ P < 0.001 CAD vs Healthy. Results were evaluated by repeated-measures ANOVA (among 4 modes) by independent samples t-test (among 2 groups).

FIGURE 9

Comparison of the ratio of FR (A), MV (B), PSV (C), MDV (D), and the D/S value (E) in the RB between the patient and healthy groups, *P < 0.05 EECP-P30 vs another EECP state, **P < 0.01 EECP-P30 vs another EECP state, ***P < 0.001 EECP-P30 vs another EECP state, ⁺ P < 0.05 CAD vs Healthy, ⁺⁺ P < 0.01 CAD vs Healthy. Results were evaluated by repeated-measures ANOVA (among 4 modes), by independent samples t-test (among two groups).

FIGURE 10

FR (A), MV (B), PSV (C), MDV (D), and ratio of EECP-P20 (20 kPa, T wave, 1:1), EECP-P25 (25 kPa, T wave, 1:1), EECP-P30 (30 kPa, T wave, 1:1), and EECP-P35 (35 kPa, T wave, 1:1) of AO in the healthy group, *P < 0.05 the EECP vs another EECP state. Results were evaluated by repeated-measures ANOVA (among four modes).

FIGURE 11

FR (A), MV (B), PSV (C), MDV (D), and ratio of EECP-P20 (20 kPa, T wave, 1:1), EECP-P25 (25 kPa, T wave, 1:1), EECP-P30 (30 kPa, T wave, 1:1), and EECP-P35 (35 kPa, T wave, 1:1) of RF in the healthy group, *P < 0.05 the EECP vs another EECP state, **P < 0.01 the EECP state vs another EECP state, ***P < 0.001 the EECP vs another EECP state. Results were evaluated by repeated-measures ANOVA (among 4 modes).

FIGURE 12

FR (A), MV (B), PSV (C), MDV (D), and ratio of EECP-P20 (20 kPa, T wave, 1:1), EECP-P25 (25 kPa, T wave, 1:1), EECP-P30 (30 kPa, T wave, 1:1), and EECP-P35 (35 kPa, T wave, 1:1) of RB and the D/S value (E) in the healthy group, *P < 0.05 the EECP state vs another EECP state, **P < 0.01 the EECP vs another EECP state, ***P < 0.001 the EECP vs another EECP state. Results were evaluated by repeated-measures ANOVA (among 4 modes).

FIGURE 13

FR (A) and MV (B) of AO, FR (C) and MV (D) of RB, FR (E), and MV (F) of RF for different EECP modes.