Effect of local cold provocation on systolic blood pressure and skin bloodflow in the finger

Demonstration of increased vascular cold reactivity in patients with Raynau d's syndrome is difficult. For medico-legal reasons, it is important to get objective measures of vasospasm in these patients. Evaluation of the degre e of vasospasm also provides prognostic information which is useful for pat ient management. In this study, we compare two methods of arterial circulat ion measurement. The laser Doppler scanning is a new method, which uses the recently developed laser Doppler perfusion imaging (LDPI) instrument. The aim of the present study was to compare the effect on finger skin blood flo w measured with LDPI with changes in finger systolic blood pressure during local cold provocation. The effect of such provocation, skin blood flow and systolic blood pressure, were studied in 15 healthy controls. Six patients with known traumatic vasospastic disease (TVD) were also tested with both methods. Finger skin blood flow was measured with LDPI on the distal phalan x of the index finger of the left hand, every minutes during 6 min of local heating at 40 degreesC followed by local cooling for 3 min at 15 degreesC and then for 3 min at 10 degreesC. Finger systolic blood pressure was measu red with strain-gauge method before and after local cooling to 10 degreesC with a cuff perfused with water of desired temperature. The test was perfor med in the same finger within a week of the laser Doppler scanning. Local f inger cooling to 15 degreesC and 10 degreesC caused a significant decrease in blood flow, most marked at 10 degreesC. There was, however, no correlati on between the decrease in blood flow and blood pressure. In the TVD-patien ts decreases in skin blood flow were similar compared with the healthy cont rols. In contrast, the changes in systolic blood pressure, were outside nor mal range (systolic quotient <0.65) in five of the six patients (83%), and also in 11 of the 15 healthy controls (73%). In conclusion, there is no cor relation between the decrease in finger skin blood flow and systolic blood pressure during local cold provocation. For diagnosis of traumatic vasospas tic disease (TVD), local cold-induced changes in finger systolic blood pres sure seems superior to changes in skin blood flow, but the ideal clinical m ethod for demonstrating increased cold-induced vasospasm is, however, still lacking.