Diagnostic value of nailfold videocapillaroscopy in systemic sclerosis secondary pulmonary arterial hypertension: a meta-analysis

Background: Microvascular changes play a decisive role in systemic sclerosis (SSc) and occur early in the course of the disease. Pulmonary arterial hypertension (PAH) represents one of the main clinical expressions of the vascular changes in SSc, and the abnormal changes, especially capillary density and capillary width, are detectable at nailfold videocapillaroscopy (NVC). Aims: To investigate the differences in capillary nailfold changes in SSc patients with and without PAH and to estimate the early diagnostic value of NVC in SSc secondary PAH (SSc-PAH). Methods: A comprehensive literature search of MEDLINE and PUBMED was performed to identify published studies without language restrictions. The methodological quality of the included studies was evaluated. The pooled specificity, sensitivity, positive likelihood rate, negative likelihood rate, diagnostic odds ratio, area under the curve and Q value were found using Meta-Disc version 1.4 software packages. Finally, seven studies were included in this meta-analysis. Results: The meta-analysis demonstrated that the diagnostic odds ratio, area under the curve and Q value were 5.84 (95% confidence interval: 1.95-17.54), 0.79 and 0.72 respectively. It indicated that the microvascular changes detected at NVC were significant in SSc-PAH and especially showed significantly lower capillary density and higher capillary width. Conclusion: The NVC may be a valuable tool for the early diagnosis of SSc-PAH. It can detect the early microvascular changes associated with the risk of PAH and has a significant role in the early prediction of SSc-PAH.