Abnormalities of cardiac autonomic nervous activity correlate with expansive coronary artery remodeling

Vagal fibres are distributed both in the perivascular connective tissue and in the adventitia around the circumference of arteries, and contribute to coronary artery dilation. The aim of the manuscript is to examine whether morphologic changes of the vessel wall due to the atherosclerotic process might be associated with autonomic nervous system dysfunction.

We studied 42 patients with single vessel disease referred for percutaneous coronary revascularization. Patients underwent intravascular ultrasound at the site of the ischemia-related artery before intervention. The autonomic nervous system activity was assessed by the analysis of heart rate variability (HRV) in the frequency domain. The high frequencies (HF) are predominantly under the influence of the parasympathetic system, while the low/high frequency (LF/HF) ratio represents an index of sympatho-vagal balance. Plaque plus media cross-sectional area was inversely related to HF components (r=-0.34, p<0.05), and directly related to LF/HF ratio (r=0.38, p<0.05). Patients with expansive remodeling showed lower HF values (0.07+/-0.06 nu versus 0.14+/-0.09 nu, p<0.01) and higher LH/HF ratio (2.1+/-1.1 versus 1.4+/-1.1; p<0.05). LF changes were independent of any morphologic features. On multivariate analyses the remodeling index was the only independent determinant of HF and LF/HF ratio.

Outward stretch of the vessel wall behind the plaque, as a consequence of increasing plaque size and expansive arterial remodeling is associated to autonomic dysfunction namely due to impairment of the vagal tone. It is unknown if remodeling is a cause of vagal impairment or if vagal impairment may contribute to arterial remodeling.