TABLE 3.
Associations between exercise capacity measures (steps achieved and measured V̇O2) and indices of post-occlusive reactive hyperaemia (PORH); or tissue saturation index (TSI); changes during exercise measured in the lower-limb. ∆TSIBL-EE is the change in TSI, between rest (baseline, BL) and the end of exercise (EE); ∆TSIINC-MIN is the change in TSI from its highest point at the INC, increment; to its MIN, minimum; ∆TSIBL-INC is the change in TSI from the BL to the highest point (INC).unadj, Unadjusted; and adjusted β-coefficients, 95% confidence intervals and p-values are presented for each association. M1, Model 1; is adjusted for age, sex and ethnicity. Associations between PORH measures and exercise capacity were also adjusted for height and ischaemic duration in M1. *indicates models also adjusted for estimated workload (W).
| Exercise capacity measured β-coefficient (95%CI) | ||||
|---|---|---|---|---|
| NIRS measures | Steps achieved | VO2 achieved (ml/min) | ||
| Unadj | M1 | Unadj | M1 | |
| n = 153 | n = 153 | n = 148 | n = 148 | |
| Time to 50% PORH (s) | −5.3 (−10.0,-0.66) 0.026 | −2.7 (−7.1.1.7) 0.221 | −21.9 (−44.8.1.0) 0.061 | −6.2 (−25.7.13.2) 0.528 |
| Time to 95% PORH (s) | −1.3 (−2.6.0.04) 0.056 | −0.42 (−1.7.0.87) 0.525 | −6.1 (−12.5.0.36) 0.064 | −0.54 (−6.3.5.2) 0.852 |
| Time to 100% PORH (s) | −0.29 (−0.86.0.28) 0.315 | 0.11 (-0.48.0.70) 0.709 | −1.3 (−4.1.1.4) 0.339 | 1.1 (−1.5.3.7) 0.406 |
| Recovery rate PORH (1/s) | 699 (140,1259) 0.015 | 306 (−235,848) 0.266 | 3835 (1127,6542) 0.006 | 1383 (−1016,3782) 0.256 |
| AUC PORH (µM x s) | 20.8 (4.8.36.7) 0.011 | 18.0 (2.3.33.7) 0.025 | 90.8 (12.0,169.6) 0.024 | 22.5 (−48.2.93.1) 0.531 |
| ∆OxyHb PORH (µM) | 1.3 (0.46.2.1) 0.002 | 0.86 (0.10.1.6) 0.027 | 4.4 (0.21.8.7) 0.040 | −0.13 (−3.8.3.5) 0.944 |
| n = 558 | n = 558 | n = 495 | n = 495 | |
| ∆TSI BL-EE | 4.1 (2.6.5.6) | 1.7 (0.49.2.9) | 24.7 (17.8.31.7) | 7.7 (3.2.12.3) |
| <0.001 | 0.006* | <0.001 | 0.001* | |
| ∆TSI INC-MIN | 3.6 (1.9.5.2) | 2.5 (1.3.3.8) | 16.4 (8.7.24.1) | 6.6 (1.9.11.3) |
| <0.001 | <0.001* | <0.001 | 0.006* | |
| n = 478 | n = 478 | n = 427 | n = 427 | |
| ∆TSI BL-INC | 2.8 (0.14.5.4) | −1.2 (-3.6.1.3) | 24.0 (11.8.36.1) | 1.7 (-9.3.12.7) |
| 0.039 | 0.352 | <0.001 | 0.764 | |
| ∆TSI BL-INC | 2.9 (0.22.5.5) | −1.1 (−3.5.1.3) | 24.9 (13.0.36.9) | 2.2 (−8.5.12.8) |
| Adj. ∆MAP | 0.034 | 0.381 | <0.001 | 0.687 |