Aims: There are discrepant data on the prevalence of vascular compression of the rostral ventrolateral medulla, discussed as a possible cause of essential hypertension, in patients with essential and secondary hypertension. We therefore evaluated the comparative prevalence of neurovascular compression in two large and well defined patient groups with severe essential and secondary hypertension.
Patients and methods: 121 patients with long-standing severe (requiring at least three antihypertensive agents for adequate control of blood pressure) essential or secondary hypertension and extensive examination for causes of secondary hypertension were recruited. The presence of neurovascular compression was assessed independently by a neuroradiologist and a neurosurgeon in MRI images for all patients. The subgroup of patients with the highest prevalence of neurovascular compression was identified by CART-analysis.
Results: 5 of 121 formerly included patients (4.1%) were excluded for diverging MRI assessments. Neurovascular compression was diagnosed in 50 of 68 patients (73.5%) with essential hypertension and 6 of 48 patients (12.5%) with secondary hypertension. The odds ratio for diagnosis of neurovascular compression in patients with essential hypertension was 19.4 (95%-confidence interval 7.9-47.9) compared to patients with secondary hypertension. CART-analysis identified the highest prevalence of neurovascular compression in patients with severe essential hypertension younger than 67.5 years.
Conclusions: Since successful decompression or implantation of a carotid sinus stimulator in patients eligible for surgery may lead to substantial improvement in blood pressure in patients in whom blood pressure could not be lowered below 140/90 mmHg by antihypertensive treatment alone MRI screening for the presence of neurovascular compression is justified in patients meeting all of the following three criteria: exclusion of secondary hypertension after extensive examination; hypertension uncontrollable with antihypertensive treatment alone, and age younger than 67.5 years.