PP.29.09] NEW CLASSIFICATION OF CEREBROVASCULAR REACTIVITY DISORDERS AND THE FREQUENCY OF OCCURRENCE FOR THESE DIFFERENT TYPES

Abstract

Objective: The aim of the study was to develop new classification of cerebrovascular reactivity (CVR) disorders after metabolic stress tests and the frequency of occurrence determine for these changes in groups patients with duration of essential hypertension (EH) more than 5 years or less. Design and method: All participants of research have given the informed agreement. We used ultrasonography of transcranial Doppler‘s method in the middle cerebral arteries and apparatus with metering rate during hypercapnia (inhalation 2 min 4% mixture of carbonic gas with air (hypercapnia) and in periods of recovery air-inhalation 2 min of 258 patients (age 52.7 ± 11.2years) with duration of EH more than 5 years or less. Determinacy arterial reaction is achieved by using the original device, it have low resistance of the respiratory system, the minimum volume of ’dead’ area, stable concentration of the gas mixture. We used Indexes of the flow velocity mean (FVm); IFVm = (Vm0-Vm)|Vm0*100, Speed Modification of FVm: SM = (Vm-Vm0)|120, Index of Recovery of FVm: IR = Vm0|Vmrec:Vm0 is starting and Vm is the parameters at period of inhalation, Vmrec is Vm after 120 sec. Results: New classification: patients with H had different types of CVR hypercapnia-reactions and different frequency of occurrence of patients less then 5 or more then 5 years: normal 50%< IFMm <70%, abnormal reduced IFVm < 50%, abnormal enhanced IFVm > 70% and 67; 33; 0/34; 59; 7% χ2 = 34.0; 5.0; 92.0; p = 0.000; 0.005; 0.000 respectively; 3 types of speed-reactions: normal 0.25 < SM < 0.40, abnormal slow SM < 0.25 and abnormal accelerated SM FVm > 0.40 and 65; 35; 0/24; 71; 6% χ2 = 34.0; 26.0; 6.2 p = 0.00; 0.00; 0.01 respectively; 2 types of recovery-reactions: normal recovery (Vmrec>1.0), abnormal slow recovery (Vmrec < 1.0) and 65; 35/52; 48 χ2 = 3.5 p = 0.06 respectively. Conclusions: Cerebrovascular reactivity can be classified by objective quantitative thresholds. These were force of response, speed of reaction and speed of recovery after load. Hypertensive patients had a different incidence of disorders the CVR after metabolic stress tests with duration of essential hypertension more than 5 years or less.