Altered blood vessel responses in the eye and finger in coronary artery disease.

Purpose: Cardiac function, such as heart rate variability, is abnormal in coronary artery disease, but its relation with function of ocular and nail fold blood vessels is unknown. We hypothesised abnormal retinal and peripheral microvascular endothelial function compared to large blood vessel and cardiac function in 24 patients with coronary artery disease (CAD) and 30 healthy age and sex matched controls. Methods: Peripheral microcirculatory function was measured using continuous retinal vessel diameter assessment and nail fold capillaroscopy. Systemic vascular function was evaluated by 24 hr blood pressure, arterial stiffness, low frequency (LF) and high frequency (HF) heart rate variability, ECG monitoring, and plasma markers von Willebrand factor (vWf) and soluble E selectin. Results: Peripheral nail-fold capillary responses (p=0.009) and retinal vessel responses (average baseline corrected flicker response [BFR] (p=0.034) and reaction time to flicker (p=0.016)) were significantly different in patients compared to controls. Furthermore, patients demonstrated higher arterial stiffness (p=0.005), LF and HF heart rate variability (p=0.004, p=0.006), and vWf (p=0.044) but there was no difference in soluble E selectin (p=0.278). In CAD patients, LF and HF heart rate variability both correlated with average BFR (r=0.58, p=0.004 and r= -0.6, p=0.003 respectively). There was no such relationship in the healthy controls. Conclusions: Microcirculatory abnormalities of the retina and nail-fold vessels are present in CAD. The two indices of heart rate variability correlated with an index of ocular vessel responses. We suggest that the latter may be a surrogate marker of abnormal heart rate variability in CAD.