Analysis of cerebrovascular reactivity and peripheral endothelial dysfunction in patients with a high-grade carotid stenosis undergoing carotid endarterectomy (CEA).

A high-grade carotid atherosclerosis is known to compromise cerebrovascular reactivity (CVR), which may improve after CEA, a change often attributed to myogenic mechanisms. Apart from being a risk factor for stroke, impaired CVR is also suggested to reflect a generally impaired vascular system. We investigated whether changes in CVR are paralleled with signs of peripheral endothelial dysfunction.

We included 61 patients with a high-grade carotid stenosis (≥70% by NASCET criteria), either asymptomatic or symptomatic without a visible infarction, scheduled for CEA, in the analysis. They underwent transcranial Doppler ultrasound (TCD) with breath-holding index (BHI) and noninvasive endothelial function testing (EndoPat®) prior to and 6 months after CEA, and their secondary prevention was optimized according to routine standard of care. The control group consisted of 40 strictly healthy age-matched individuals with no medication. 

At baseline, the patients had a higher BMI than controls (27.8 vs. 25.0).  BHI values were lower in patients (0.88 vs. 1.06, p=0.003), and there was no difference in the natural logarithm of reactive hyperemia index (Ln RHI) reflecting endothelial function (0.59 vs 0.69, p=.19).  At 6 months, the BHI of patients had improved significantly (0.95, p=0.01), but their Ln HRI appeared significantly lower indicating poorer endothelial function (0.54 vs. 0.69, p<0.01).

The positive effect of CEA on impaired CVR is a vascular bed-specific response which does not reflect improvement in general endothelial function in the course of other secondary preventive measures.