Arterial distensibility and ambulatory blood pressure monitoring in young patients with neurofibromatosis type 1

Vascular disease is an underestimated complication of neurofibromatosis typ e 1 (NF1). The few studies available on this disease are based on case repo rts. The purpose of this study was to evaluate the relationship between 24- h systolic blood pressure (SBP) and 24-h heart rate obtained by ambulatory blood pressure monitoring and the carotid femoral pulse wave velocity, a wi dely used index of arterial distensibility, evaluated with Complier. We stu died 64 young NF1 patients and 30 healthy subjects. There was no difference in pulse wave velocity between NF1 patients and healthy subjects. Ten of t he NF1 patients showed 24-h SEP or 24-h diastolic blood pressure (DBP) > 95 th percentile for age and sex. We divided the NF1 group into subgroups: NF1 patients with 24-h SEP and 24-h DBP less than or equal to 95th percentile for age and sex (NF1, group) and NF1 patients with mean SEP or DBP >95th pe rcentile for age and sex (NF1, group). The pulse wave velocity of NF1(A) an d NF1(B) patients were 6.3 +/- 1 m/sec and 6.4 +/- 1 m/sec, respectively (P = not significant). A significant relationship was found between 24-h SEP, 24-h heart rate, and pulse wave velocity in healthy subjects, but not in a ll NF1 patients and also between the NF1(A) and NF1(B) groups. Distensibili ty of the central arteries may be altered by various environmental or genet ic factors. Thus, genetic determinants may play a role in the response of t he large arteries to blood pressure. The recent discovery of neurofibromin in aortic smooth muscle may explain the vascular abnormalities present in N F1 patients. We emphasize the importance of a careful vascular evaluation u sing a noninvasive method, such as Complier and a periodic ambulatory blood pressure monitoring to detect NF1 patients at high risk of vascular compli cations. (C) 2001 American Journal of Hypertension, Ltd.