Management of Resistant Hypertension in Patients with Carotid Stenosis: High Prevalence of Renovascular Hypertension

Abstract

Introduction: Patients with carotid stenosis are at high risk of vascular events and therefore require an optimal control of risk factors such as hypertension. As the treatment of hypertension differs according to the cause, we examined the prevalence of resistant hypertension, and the cause of hypertension, among patients with carotid stenosis followed closely in two randomized trials of carotid endarterectomy. Objective: The purpose of this study was to determine the prevalence of resistant hypertension and of secondary hypertension among patients with carotid stenosis. Methods: A chart review was performed of all patients from our center who participated in the North American Symptomatic Carotid Endarterectomy Trial or the Asymptomatic Carotid Artery Study to determine the prevalence of renovascular hypertension. Results: Among 170 patients with carotid stenosis followed in these two trials, 145 (83.5%) were hypertensive (systolic >160 or diastolic >90 mm Hg); at least 24 (14.1% overall, 16.6% of hypertensives) had renovascular hypertension based on either nuclear medicine renography, renal angiography or both; among the 79 patients with resistant hypertension (mean arterial pressure >130 mm Hg despite treatment), 20 (25.3%) had renovascular hypertension. Adrenocortical hyperplasia was the underlying cause of hypertension in 12 (7.1% of cases, 8.3% of hypertensives, 8.8% of resistant hypertensives). Blood pressures were significantly higher for patients with renovascular and adrenocortical hypertension (p < 0.0001 for systolic, p = 0.024 for diastolic pressures). Conclusion: Among patients with carotid stenosis, renovascular hypertension is unusually common. Resistant hypertension among such patients should lead to investigation and management directed at the cause of hypertension. Appropriate investigations might include plasma renin/aldosterone ratio, captopril renography and MRA of the renal arteries or renal angiography.

Clinical Management of Resistant Hypertension

“…Higher prevalence of subclinical organ damage can be found in patients with resistant hypertension, including left ventricular hypertrophy [18], intima-media thickening and carotid atheroma [19], hypertensive retinopathy, albuminuria and initial impairment of renal function [20,21].…”

New treatment options for hypertension during acute ischemic or hemorrhagic stroke

“…The mechanism has been called "kicking the back door out of the glomerulus" [23]. I have reported that among patients with carotid stenosis and resistant hypertension, 25% have renovascular hypertension [24]. Therefore, oral angiotensin-converting enzyme inhibitors or angiotensin II receptors are not safe in patients with stroke.…”

With what to treat which patient with recently symptomatic carotid stenosis?

“…However, it is likely that patients with large-artery atherosclerosis will benefi t. Many physicians are, however, cautious about lowering blood pressure, particularly in patients with severe bilateral carotid stenosis or occlusion. These patients often also have disease of the vertebral arteries, the carotid siphon, and the cerebral arteries (Thiele et al 1980;Gorelick 1993) and have a particularly high risk of recurrent stroke (Spence 2000). Loss of the normal autoregulatory capacity of the cerebral circulation, such that cerebral blood fl ow is directly dependent on systemic blood pressure, is common (Van der Grond et al 1995;Grubb et al 1998), and there has been natural concern that blood pressure lowering may reduce cerebral perfusion and increase the risk of stroke.…”