Objectives: The recently developed cold stimulus fingertip lacticemy test (CS-FTL) provides biochemical assessment of peripheral perfusion in patients with Raynaud's phenomenon (RP). We evaluated how the CS-FTL test can assess the acute effect of nifedipine in microvascular dynamics on primary RP and RP secondary to SSc.
Methods: A double-blinded controlled trial with crossover design was performed in 20 primary RP and 20 SSc patients. Patients received one single sublingual placebo or 10 mg nifedipine capsule, with crossover after a 15-day washout period. FTL was determined in resting conditions (pre-CS-FTL) and 10 min after CS (post-CS-FTL), before and 1 h after drug administration. Percent variation in post- vs pre-CS-FTL was expressed as deltaCS-FTL.
Results: Before intervention, CS induced FTL decrease in primary RP (deltaCS-FTL = -21.3 +/- 13.0%) and FTL increase in SSc patients (deltaCS-FTL = +24.5 +/- 21.2%). Placebo had no effect on pre-CS-FTL, post-CS-FTL and deltaCS-FTL in primary RP and SSc. Nifedipine induced a significant decrease in pre-CS-FTL (1.94 +/- 0.45 vs 1.57 +/- 0.41 mg/dl; P = 0.005) and post-CS-FTL (1.53 +/- 0.35 vs 1.32 +/- 0.37 mg/dl; P = 0.004) in primary RP and a significant decrease in post-CS-FTL (3.18 +/- 1.43 vs 2.56 +/- 1.30 mg/dl; P = 0.028) and deltaCS-FTL (+15.9 +/- 24.7% vs -12.9 +/- 16.6%; P = 0.001) in SSc.
Conclusions: The CS-FTL test was able to demonstrate and quantify a dual effect of nifedipine on the biochemical dimension of peripheral perfusion in primary RP and in SSc patients in which there was a significant improvement in tissue perfusion in resting conditions and after exposure to a CS. The CS-FTL test will enrich the armamentarium for investigation and clinical evaluation of conditions associated with RP.