Table 2. CV parameter estimation methods assessed in this study.
| Parameter | Description | Sce | Ref | Abb | Percentage Error, % | |
|---|---|---|---|---|---|---|
| 0-D dataset | 1-D dataset | |||||
| Left ventricular ejection time, LVET | dP/dt analysis, 1 | + | (32) | LV1 | ‡ | 0.4 ± 1.0 |
| dP/dt analysis, 2 | + | (37) | LV2 | –12.4 ± 0.1 | –5.7 ± 4.1 | |
| 0.37 | +, – | (31) | LV3 | 26.1 ± 8.5 | 6.9 ± 8.1 | |
| Q analysis | +, – | † | LV4 | 0.1 ± 0.2 | 0.3 ± 0.6 | |
| Outflow pressure, P out | Diastolic decay fit, 1 | + | (15, 26) | OP1 | 0.0 ± 0.0 | –5.1 ± 8.0 |
| Diastolic decay fit, 2 | + | (15, 44) | OP2 | 0.0 ± 0.0 | –10.5 ± 7.5 | |
| 0.5 DBP | +, – | † | OP3 | 1.6 ± 16.9 | 9.1 ± 11.0 | |
| 0.7 DBP | +, – | (56) | OP4 | 42.3 ± 23.6 | 52.7 ± 15.4 | |
| Arterial resistance, R T | + | (15) | AR1 | 0.0 ± 0.0 | 0.0 ± 0.1 | |
| +, – | (22, 15) | AR2 | 0.7 ± 5.7 | –4.9 ± 2.9 | ||
| Arterial compliance, C T | 2-point diastolic decay | + | (15) | AC1 | –0.1 ± 0.0 | –6.5 ± 4.9 |
| Diastolic decay fit, 1 | + | (15) | AC2 | 0.0 ± 0.0 | –6.6 ± 3.3 | |
| Diastolic decay fit, 2 | + | (15, 44) | AC3 | 0.0 ± 0.0 | –10.2 ± 5.0 | |
| Area method | + | (27, 41, 26) | AC4 | –10.0 ± 4.1 | –11.4 ± 4.6 | |
| Two-area method | + | (43, 26) | AC5 | –10.0 ± 4.1 | –7.1 ± 7.1 | |
| DBP method | +, – | † | AC6 | –1.5 ± 4.1 | –17.3 ± 7.5 | |
| PP method | +, – | (25, 26) | AC7 | –0.1 ± 0.2 | –27.6 ± 11.6 | |
| SV/PP | +, – | (27) | AC8 | –13.8 ± 20.3 | 4.9 ± 18.4 | |
| Optimized 3-Wk | + | † | AC9 | 0.0 ± 0.3 | –0.8 ± 4.2 | |
| Pulse wave velocity, PWV | Foot-to-foot: Q Ao | +, – | (35) | PV1 | – | 8.2 ± 6.0 |
| Foot-to-foot: P c-f | + a | (35) | PV2 | – | 27.8 ± 10.8 | |
| Least-squares: Q Ao | +, – | (35) | PV3 | – | –12.7 ± 8.3 | |
| Least-squares: P c-f | + a | (35) | PV4 | – | 43.0 ± 36.0 | |
| Sum of squares | + | (34) | PV5 | – | 33.2 ± 17.2 | |
| Characteristic impedance, Z 0 | Frequency methods | + | (29, 33, 23, 36, 38, 40, 24, 42) | Z1 | 2.5 ± 2.1 | 64.6 ± 44.3 |
| PQ-loop methods | + | (23, 28, 45) | Z2 | 0.2 ± 1.4 | 13.4 ± 56.6 | |
| 0.05 R T | +, – | (39, 46) | Z3 | –1.5 ± 40.8 | 133.8 ± 66.7 | |
| (MBP - DBP)/Q max | +, – | † | Z4 | –38.7 ± 12.4 | 82.3 ± 32.6 | |
| ρPWV/A | +, – | (47) | Z5 | – | 90.4 ± 18.1 | |
| Optimized 3-Wk | + | † | Z6 | –0.1 ± 0.7 | 37.1 ± 20.0 | |
Errors are presented as the means ± SD of the percentage error between estimated and reference CV parameter values. A, aortic root cross-sectional area; Abb, coded abbreviations used to refer to each method; DBP, diastolic blood pressure; MBP, mean blood pressure; P, peripheral BP waveform; PP, pulse BP values from P; P c-f, carotid–femoral blood BP wave pair; Q, aortic root flow waveform; , mean value of Q over T; Q Ao, ascending and descending aorta flow wave pair; Q max, peak aortic flow; Ref, references; Sce, clinical scenarios (+: carotid +, carotid–); SV, stroke volume; T, duration of cardiac cycle; 3-Wk, 3-element Windkessel; ρ, blood density. Performance was assessed in two clinical scenarios (carotid +: carotid BP wave available; carotid–: only brachial DBP and SBP available) using the 0-D and 1-D datasets (Fig. 1A).
Newly proposed methods (described in appendix B).
BP waves from the 0-D dataset do not present a second systolic peak as required by LV1.
BP waves at the carotid and femoral arteries required.