Microvascular changes on nailfold capillaroscopy in acute stage of Kawasaki disease: a new diagnostic paradigm for an enigmatic condition.

Objectives: Kawasaki disease (KD) is a medium vessel vasculitis with a predilection to involve coronary arteries. However, there is a paucity of literature on microvascular changes in patients with KD.

Methods: Children diagnosed with KD based on American Heart Association guidelines 2017 were enrolled prospectively. Demographic details and echocardiographic changes in coronaries were recorded. Nailfold capillaries were assessed using Optilia Video capillaroscopy and data were analysed using Optilia Optiflix Capillaroscopy software at acute (prior to IVIG administration) and subacute/convalescent phase.

Results: We enrolled 32 children with KD (17 boys) with a median age of 3 years. Nailfold capillaroscopy (NFC) was performed in 32 patients in the acute phase (compared with 32 controls) and in 17 during the subacute/convalescent phase at a median follow-up of 15 (15-90) days after IVIG treatment. The following findings were seen in NFC in the acute phase of KD: reduced capillary density (n = 12, 38.6%), dilated capillaries (n = 3, 9.3%), ramifications (n = 3, 9.3%) and capillary haemorrhages (n = 2, 6.2%). Capillary density was reduced significantly in the acute phase of KD (38.6%) as compared with the subacute/convalescent phase (25.4%) (P-value <0.001) and controls (0%) (P-value = 0.03). We observed no correlation between coronary artery involvement and mean capillary density (P = 0.870).

Conclusion: Results show that patients with KD have significant nailfold capillary changes in the acute phase. These findings may provide a new diagnostic paradigm for KD and a window to predict coronary artery abnormalities.