Cold stimulus fingertip lacticemy test—an effective method to monitor acute therapeutic intervention on primary Raynaud's phenomenon and systemic sclerosis
Rheumatology Division, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil.
Correspondence to: L. E. C. Andrade, Rheumatology Division, Escola Paulista de Medicina, Universidade Federal de São Paulo (UNIFESP), Rua Botucatu 740, 3° andar, São Paulo, SP 04023-062, Brazil. E-mail: luis{at}reumato.epm.br
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Abstract |
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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 
CS-FTL.
Results. Before intervention, CS induced FTL decrease in primary RP (CS-FTL = –21.3 ± 13.0%) and FTL increase in SSc patients (CS-FTL = +24.5 ± 21.2%). Placebo had no effect on pre-CS-FTL, post-CS-FTL and 
CS-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 CS-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.
KEY WORDS: Raynaud's phenomenon, Systemic sclerosis, Lactate, Microcirculation, Calcium channel blockers
Submitted 27 May 2007;
revised version accepted 10 October 2007.
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