Neurovascular compression at the lateral medulla. A pathogenetic factor in hypertension?

Based on clinical observations related to trigeminal dysfunction of vascular origin during the development of forms of so called "essential" hypertension it was suggested that there is a vascular influence on circulatory centers in the brain stem through pulsatile vessel lo7ops. This hypothesis has been supported by the results of several studies. In a histological-pathological study at the Hannover Medical School, postmortal examinations of all 24 essential hypertension patients studied revealed a neurovascular compression on the left side of the ventrolateral medulla, while in the control group of 21 normotensive persons and 10 patients with hypertension of renovascular origin no indications of a compression could be detected. Comparative histopathological studies of the brain stem failed to demonstrate any differences between the groups. In a retrospective radiological study, the angiographs of 107 patients with essential hypertension were compared with those of 100 normotensive patients aged 40 to 70. In about 80% of all hypertensive patients contact of an artery in the marker region of the root entry zone was found, in most cases involving the posterior inferior cerebellar artery (PICA). The probability for the presence of hypertension when vessels from both the PICA and the vertebral artery in the marker region were in contact yielded at 90%. When only the PICA was involved, the probability revealed at 82,9%. Intravital studies on patients who had suffered from arterial hypertension for a long time showed a significant postoperative improvement in the systolic and diastolic blood pressure after microsurgical vascular decompression, permitting antihypertensive therapy to be completely discontinued. The results of the study as well as recent literature on magnetic resonance imaging studies suggest that an operative pilot study of microsurgical decompression should be undertaken on patients with selected hypertension.