Characterization of the non-invasive assessment of the cutaneous microcirculation by laser Doppler perfusion scanner.
ABSTRACT Microcirculatory dysfunction contributes to morbidity and mortality in vascular diseases. Here, we aimed at establishing a sensitive and valid method to measure microvascular reactivity during post-occlusive reactive hyperemia (PORH) using scanning laser Doppler perfusion imaging (LDPI) of the forearm.
In a first series, LDPI was methodologically evaluated on the volar forearm of healthy volunteers (n = 10) before and after one to five minutes of upper arm occlusion. In a second series, readings were performed in 20 healthy subjects and 20 patients with coronary artery disease (CAD).
Three minutes of forearm occlusion were sufficient to induce maximal vasodilation during PORH as indicated by maximal increase in perfusion unit (PU) amplitude that did not further increase after five-minute occlusion. Five-minute occlusion led to a significant prolongation of PORH with greater area under curve (AUC) suggesting longer lasting vasodilation of microvessels. The five-minute occlusion was associated with lower variability as compared with three minutes (intraindividual variability: 9-17% vs. 12-21%; interindividual variability: 13-24% vs. 14-26%). CAD patients exhibited significantly reduced amplitude (105 +/- 49 vs. 164 +/- 35 PU; p < 0.001), ratio (4.7 +/- 1.8 vs. 7.1 +/- 1.8; p < 0.001), and AUC (1656 +/- 1070 vs. 2723 +/- 864 PU x minutes; p = 0.001).
Scanning LDPI is a feasible and reproducible method for non-invasive assessment of the cutaneous microcirculatory response during PORH.