State of the Art on Nailfold Capillaroscopy
More than 90% of patients with clinically overt SSc show a scleroderma pattern on capillaroscopy (Fig. 3). This pattern may be recognized on visual inspection (= qualitative assessment) by several types of microscope, at different magnifications.
(Enlarge Image)
Figure 3.
NVC scleroderma patterns early, active and late vs normal capillary array—magnification 200×.
Last century the most frequently used magnification was the widefield technique (low magnification, e.g. magnification ×12) with which a whole nailfold can be evaluated in one capillaroscopic image. With this technique Maricq described the hallmark articles attesting a specific pattern to be present in a SSc population vs healthy controls and other CTDs.
This century, with the high magnification (e.g. magnification ×200) technique (which better visualizes the capillaries themselves but only one-fourth of the nailfold per capillaroscopic image) Cutolo et al. classified these scleroderma patterns into early, active and late scleroderma patterns.
Logically, as SSc is characterized by progressive obliteration of the microcirculation, each of these consecutive patterns consists of a higher proportion of capillary loss.
Besides that, each of the patterns is also characterized by a different prevalence of characteristic markers of the disease, more specifically giant capillaries, haemorrhages (both present in the early and frequent in the active SSc pattern), SSc and aberrant morphological microvascular shapes (so-called neoangiogenetic capillaries, present in the active and frequent in the late pattern).
Pathognomonic in preclinical SSc (presence of merely RP and an SSc-specific antibody, see above) is the presence of giant capillaries (defined when using the widefield technique as definitely enlarged capillaries, with a loop width of 90–150 μm and apical limb diameter of >50 μm and in line with this when using the high magnification technique as homogeneously enlarged capillaries, with apical diameter >50 μm). The occurrence of clinically overt disease coincides with the occurrence of loss of capillaries, as attested in a large longitudinal follow-up study of patients with RP, with the evolution of capillaroscopic parameters in those who were to develop SSc.
Inter-rater reliability in distinguishing scleroderma patterns from normal capillaroscopic images has been confirmed by both low and high magnification techniques.
Besides visual inspection (qualitative assessment) of the scleroderma patterns, characteristic capillary changes can also be counted (quantitative assessment), usually per linear mm.
Of those quantified capillaroscopic parameters for which inter-rater reliability has been established, the count of capillaries, giant capillaries and haemorrhages diminishes over time and neoangiogenetic capillaries augment over time when evaluated at group level.
Given this change over time of capillaroscopic parameters, capillaroscopy has been used as outcome measure in small therapeutic trials with different agents. Further large randomized controlled trials are needed to investigate the role of capillaroscopy in quantification of treatment response in terms of improvement in microvascular structure.
Use of Qualitatively and Quantitatively Assessed Scleroderma Capillaroscopic Patterns for the Diagnosis and Follow-up of SSc
More than 90% of patients with clinically overt SSc show a scleroderma pattern on capillaroscopy (Fig. 3). This pattern may be recognized on visual inspection (= qualitative assessment) by several types of microscope, at different magnifications.
(Enlarge Image)
Figure 3.
NVC scleroderma patterns early, active and late vs normal capillary array—magnification 200×.
Last century the most frequently used magnification was the widefield technique (low magnification, e.g. magnification ×12) with which a whole nailfold can be evaluated in one capillaroscopic image. With this technique Maricq described the hallmark articles attesting a specific pattern to be present in a SSc population vs healthy controls and other CTDs.
This century, with the high magnification (e.g. magnification ×200) technique (which better visualizes the capillaries themselves but only one-fourth of the nailfold per capillaroscopic image) Cutolo et al. classified these scleroderma patterns into early, active and late scleroderma patterns.
Logically, as SSc is characterized by progressive obliteration of the microcirculation, each of these consecutive patterns consists of a higher proportion of capillary loss.
Besides that, each of the patterns is also characterized by a different prevalence of characteristic markers of the disease, more specifically giant capillaries, haemorrhages (both present in the early and frequent in the active SSc pattern), SSc and aberrant morphological microvascular shapes (so-called neoangiogenetic capillaries, present in the active and frequent in the late pattern).
Pathognomonic in preclinical SSc (presence of merely RP and an SSc-specific antibody, see above) is the presence of giant capillaries (defined when using the widefield technique as definitely enlarged capillaries, with a loop width of 90–150 μm and apical limb diameter of >50 μm and in line with this when using the high magnification technique as homogeneously enlarged capillaries, with apical diameter >50 μm). The occurrence of clinically overt disease coincides with the occurrence of loss of capillaries, as attested in a large longitudinal follow-up study of patients with RP, with the evolution of capillaroscopic parameters in those who were to develop SSc.
Inter-rater reliability in distinguishing scleroderma patterns from normal capillaroscopic images has been confirmed by both low and high magnification techniques.
Besides visual inspection (qualitative assessment) of the scleroderma patterns, characteristic capillary changes can also be counted (quantitative assessment), usually per linear mm.
Of those quantified capillaroscopic parameters for which inter-rater reliability has been established, the count of capillaries, giant capillaries and haemorrhages diminishes over time and neoangiogenetic capillaries augment over time when evaluated at group level.
Given this change over time of capillaroscopic parameters, capillaroscopy has been used as outcome measure in small therapeutic trials with different agents. Further large randomized controlled trials are needed to investigate the role of capillaroscopy in quantification of treatment response in terms of improvement in microvascular structure.