Microvascular Disorders in Hand-Arm Vibration Syndrome

Objective: to assess microvascular morphological and functional changes in patients with hand-arm vibration syndrome (HAVS). Material and Methods: Thirty HAVS patients and 30 healthy controls were included. After acclimatization, all subjects underwent nailfold capillaroscopy (NFC) and infrared thermography followed by laser Doppler flowmetry measurement. NFC was performed with a microscope under 30x to 60x magnification in the eponychium of the fingers. Skin blood flow of the volar part of the fingertips was measured using laser Doppler flowmeter Periflux4001 at baseline and by lowering the arm from heart level hanging to test skin venoarteriolar microcirculatory responses. Results: Spastic narrowed capillaries or capillary dilatation and tortuosity with pericapillary oedema prevailed in the HAVS patients (p<0.001). The initial mean fingertip skin perfusion and skin temperatures in HAVS patients were significantly lower compared to the healthy controls. The veno-arteriolar indices were significantly abnormal. Loss of veno-arteriolar reflex responses was established in 36.7% of vibration induced secondary Raynaud's phenomenon patients proving local vasomotor dysfunction reflecting either postganglionar sympathetic insufficiency with vascular tone failure or altered microvascular smooth muscle cells' responses. A negative correlation was found between increasing capillary abnormalities and decreasing flow rates at rest and skin blood flow responses in venoarteriolar reflex test. Discussion: The assessment of nutritional capillary skin blood flow by capillaroscopy and global skin blood flow including thermoregulatory microcirculation by Doppler flowmetry and infrared thermography give thorough information about skin microvascular circulation and vasomotor function. Morphological and functional assessment of the cutaneous microvasculature has a crucial significance for diagnosis, prognosis and treatment of patients with hand-arm vibration syndrome.