BLOOD PERFUSION STUDIES IN CEREBROVASCULAR ACCIDENTS, HYPERTENSIVES, DIABETICS AND HEALTHY CONTROLS

The objective of this study was to compare peripheral microvasculature status non-invasively in healthy controls and recent stroke cases hav ing history of hypertension. The high risk group of patients viz. hype rtensives and diabetics were also included in the study. We used a com bination of Laser Doppler flowmetry and reactive hyperemia test along with parallel estimation of blood viscosity factors such as, hematocri t, red cell rigidity, plasma viscosity and biochemical parameters. Rea ctive hyperemia was induced by arterial occlusion for 3.5 min. duratio n in the forearm of all four groups. Basal skin perfusion before induc ing reactive hyperemia (Per(bas)), did not vary significantly in any g roup. However, the increased maximum skin perfusion after inducing rea ctive hyperemia (Per(max)) in the case of stroke and hypertension were found significantly different (p < 0.05) as compared to healthy contr ols. The recovery time (Trh) i.e., time taken for induced maximum perf usion to return to basal value, were significantly less in stroke (p < 0.05) and hypertensive groups (p < 0.001) whereas it was significantl y high in diabetic group (< 0.02) as compared to healthy controls. A r educed Trh may be considered as an indicative of myogenic dysfunction while a delayed Trh may be regarded as an indicative of metabolic dysf unction. Further the calculation of two dimensionless microcirculatory parameters reactive hyperemia perfusion index (RHPI) and reactive hyp eremia time index (RHTI) were proposed for use in preliminary screenin g of the degree of myogenic or metabolic dysfunction in various diseas e conditions. The correlation of above mentioned parameters with blood viscosity factors were discussed.