PP.17.20] CLASSIFICATION OF BRAIN ARTERIAL REACTIVITY DISORDERS IN PATIENTS WITH HYPERTENSION

Abstract

Objective: The aim of the study was to classify changes of brain arterial reactivity (BAR) during hypercapnia and hyperoxia in patients with hypertension. Design and method: All participants of research have given the informed agreement. We used ultasonography of transcranial Doppler‘s method in the middle cerebral arteries (MCA) from temporal window. We studied the changes of flow Velocity mean (Vm) starting, during hypercapnia (inhalation 2 min 4% mixture of carbonic gas (MCG) with air or hyperoxia - 100% oxygen and FmV in period of recovery (rec) (air-inhalation 2 min) of 278 patients with essentially hypertensive (BP > 140/90 mmHg without antihypertensive drugs), age 52.9 ± 10.9years. High - resolution annular array scanners was determined - a nominal axial resolution of 0.2 mm and 30 frames per second's acquisition rate with a 2.5–4 MHz sectored array transducer in the quiet dark room at the temperature 24–26 degrees Celsius. We used Indexes of FVm; IFVm = (Vm0-Vm)/ Vm0*100, Speed Modification of FVm: SM = (Vm-Vm0)/120, Index of Recovery of FVm: IR = Vm0/Vmrec: Vm0, BP0 are starting and Vm, BP are the parameters at period of inhalation, Vmrec is Vm after 120 sec. - time of inhalation. Results: New classification: patients with hypertension had 3 types of BAR hyperoxia-reactions: it were normal (IFVm < or = −20%), abnormal reduced (−20% < IFVm < 0%) abnormal opposite (IFVm > or = 0%) and 3 types of hypercapnia-reactions: normal (50% < IFVm < 70%), abnormal reduced (< 50%), abnormal enhanced (IFVm > 70%); 2 types of speed-reactions for hyperoxia: normal (SM < or = −0.12) abnormal slow (SM > −0.12) and 3 types for hypercapnia: normal (0.25 > or = SM < or = 0.40), abnormal slow (SM < 0.25) and abnormal accelerated (SM FVm > 0.40); 2 types of recovery-reactions: normal recovery (Vmrec > or = 1,0), abnormal slow recovery (Vmrec < 1,0). Conclusions: Patients with hypertension had the different types reaction of BAR after hypercapnia and hyperoxia by reaction force, its speed of development and rate of recovery. It can be classified by objective quantitative thresholds.