Magnetic resonance evaluation of ventrolateral medullary compression in essential hypertension

Abstract

There was a tendency toward left VA dominance in the hypertensive group compared with the control group, although a significant difference was shown by only one of the four reviewers. There were no differences in brainstem compression or rotation between the hypertensive and nonhypertensive groups. These results are contrary to those of recently published studies in which MR imaging and/or MR angiography revealed lateral brainstem vascular compression in hypertensive patients but not in nonhypertensive (control) patients. Reasons for this discrepancy are discussed. On the basis of their own experience and that of others, the authors believe that neurogenic hypertension does exist. However, thin-slice MR imaging may not be a reliable method for detecting neurovascularly induced essential hypertension and the prevalence of neurovascular compression as the source of hypertension may be overestimated when using current imaging techniques.

Efficacy of an L- and N-type calcium channel blocker in hypertensive patients with neurovascular compression of the rostral ventrolateral medulla

“…[37][38][39][40][41] In addition, the prevalence of NVC of the RVLM varied from 30 to 90% in essential hypertensives and from 7 to 55% in normotensives. [4][5][6][7]9,11,12,18,[37][38][39][40][41][42][43] The reason for the variation of the estimated prevalence of NVC of the RVLM may be due to the inability of MRI for the perfect and adequate assessment of the presence of NVC of the RVLM and to a lack of standardized classification of NVC of the RVLM. Investigation to establish adequate methods to assess whether NVC of the RVLM exists or not, and whether the compression is functional or not, will be needed.…”

Hypertension of neurogenic origin: effect of microvascular decompression of the CN IX-X root entry/exit zone and ventrolateral medulla on blood pressure in a prospective series of 48 patients with hemifacial spasm associated with essential hypertension

“…2,3,4,6,8,9,11,15,16,18,22,23,25,[42][43][44] In the quest for patients affected with essential hypertension to be candidates for vascular decompression, as many as 14 studies have been conducted to investigate the reliability of MRI for the detection of compressive vessels with a potential role in the genesis of hypertension. 1,10,12,21,24,28,35,37,39,45,50,57,58,61 In most of these publications, images of vascular contact/compression at the ventrolateral medulla were reported at a higher rate in patients with hypertension than in those with normal blood pressure (BP). However, statistical significance was absent when the analysis was restricted to prospective studies.…”

Neurovascular compression in essential hypertension: cause, consequence or unrelated finding?

“…An increased rate of compressions at the RVLM in hypertensive patients was not found by other researchers. [7][8][9][10] In the largest published study, 11 no difference was observed in the prevalence of compression in the left RVLM between hypertensive and normotensive subjects, but the difference became significant when assessing RVLM bilaterally.…”

“…[4][5][6] An important source of inconsistencies may be the definition of the RVLM. The extent of the RVLM was often vaguely anatomically defined, 4,9 if mentioned at all, 7 and therefore was poorly reproducible. MR technology used by some previous investigators 4-9 had low spatial resolution.…”

“…The inclusion and exclusion criteria were frequently imprecise. [7][8][9] Furthermore, previous studies were not focused on patients with severe hypertension. As arterial hypertension is an arbitrarily defined risk factor, inclusion of mildly hypertensive patients may affect the results.…”