Differences in carotid plaque morphology and echolucency between CEA with patch and eversion endarterectomy, as well as other theories, including alterations in the renin-angiotensin system, vasopressin concentrations or central catecholaminergic activity, may explain the higher rate of perioperative hypertension in CEA with patch procedures (7). The gene discussed is REN; the disease is hypertensive disorder.