Decreased capillary permeability and capillary density in patients with systemic sclerosis using large-window sodium fluorescein videodensitometry of the ankle

Objective. Local capillary permeability in patients with SSc has been reported increased when assessed by nail-fold capillaroscopy. We measured capillary permeability at a clinically less affected site by using large-window fluorescein videodensitometry of the ankle. We hypothesized that increased capillary permeability or leakage is a generalized phenomenon in SSc. Methods. Large-window videodensitometry with sodium fluorescein was performed in 38 SSc patients and 20 healthy controls. Capillary permeability was expressed as the average relative light intensity over the first 7 min [I-av(7)] after appearance of fluorescein in skin capillaries. Results. Capillary permeability, expressed as I-av(7) was significantly decreased in patients with SSc (47.3 +/- 15.0% vs 57.6 +/- 9.4% in controls, P = 0.007), as was capillary density (12 +/- 6/mm(2) vs 26 +/- 11/mm(2), P < 0.001). Adjustment for capillary density in multivariate regression analysis demonstrated that differences in I-vs(7) between SSc patients and controls were related to differences in capillary density, BMI and high density lipoprotein cholesterol. Conclusion. At the level of the ankle decreased capillary permeability was found in SSc patients, related to decreased capillary density. Microvascular involvement in SSc is widespread, but no evidence was established for increased capillary permeability at the level of individual capillaries as a generalized phenomenon.