Laser-Doppler flowmetry in peripheral arterial occlusive disease. Correlations with transcutaneous oximetry.

The place of laser-Doppler flowmetry is not well established among the other techniques of evaluation of local microcirculatory blood flow. We conducted a study in 15 controls (mean age 49.5 yrs, 30 limbs) and 37 patients with peripheral arterial occlusive disease (PAOD) (mean age 59.1 yrs, 67 limbs, 50 mild ischemia and 17 severe ischemia) and assessed the local blood flow with laser-Doppler (Perimed PF3) and transcutaneous oximetry (Hellige Oxymonitor), both probes being heated at 44 degrees C. Transcutaneous oxygen tension (TcpO2 mmHg) and laser-Doppler fluxes (LDF in perfusion units PU) were measured at the foot dorsum in resting horizontal supine position and leg dependency (30 controls, 67 PAOD) and during post-ischemic reactive hyperemia (36 PAOD). The results (mean +/- sd) were compared within each group (controls, mild ischemia, severe ischemia) by means of a paired t-test, between the different groups by a variance analysis and correlations by a Spearman test. LDF decreased from supine position to leg dependency in the control group (24.1 +/- 22.2 PU horizontal vs 19.0 +/- 26.2 dependent, N = 30, p <.05 but not in the PAOD group (mild ischemia respectively 46.0 +/- 41 vs 42.9 +/- 35 PU, N = 50; severe ischemia 41.3 +/- 27 vs 48.6 +/- 42 PU, N = 17). LDF was significantly higher at rest: mild ischemia 46 +/- 41 (N = 50), severe ischemia 41.3 +/- 27 (N = 17) vs controls 24.1 +/- 22 PU (p <.005). LDF increased during hyperemia in controls (peak flux 42.4 +/- 28.9 PU, p <.00001) and in patients with mild Ischemia (46.0 +/- 42 vs 32.5 +/- 39 PU at rest, N = 29, p <.005) but not in severe ischemia (29.4 +/- Is vs 28.7 +/- 33 PU at rest, N = 7). TcpO2 at rest (65.9 +/- 14 mmHg in 30 controls) decreased significantly in mild ischemia (55.6 +/- 16 mmHg, N = 48) and severe ischemia (32.1 +/- 26 mmHg, N = 17, p <.005). On leg dependency, TcpO2 increased in mild ischemia (70.2 +/- 13 leg dependent vs 52.6 +/- 12 mmHg horizontal, N = 21, p <.001) and severe ischemia (respectively 35.6 +/- 24 and 26.1 +/- 15 mmHg, N = 10, p <.01). No correlations were found between LDF parameters and TcpO2 except in patients with severe ischemia (LDF horizontal and dependent with TcpO2 dependent). Our study demonstrated the loss of the arteriovenular reflex in PAOD suggesting that laser-Doppler could be a sensitive indicator of the vasomotion state.