1979 Volume 16 Issue 6 Pages 536-544
Patients with cerebrovascular disease (CVD) commonly have symptoms of circulatory disorders, i.e., diziness, light headedness, idiopathic peripheral edema. and so on. These symptoms may hinder rehabilitation and interfere with the improvement of their clinical symptoms. Accordingly, it seemed important to assess the circulatory effects of postural change in order to improve medical care for patients with CVD.
The present study was designed to evaluate an orthostatic dysregulation of patients with chronic internal carotid arterial occlusion (ICAO). Effects of rapid 45° head-up tilt on systemic circulation were examined in 12 patients with ICAO (mean age of 73yrs) and 20 healthy subjects (mean age of 74yrs).
Arterial blood pressure, heart rate and cardiac output were measured by sphygnometer, electrocardiogram, and a dye-dilution method using ear-piece photocell, respectively. These measurements were performed at least twice at supine rest, and then at 0min, 5min, and 10min after tilt. These hemodynamic responses in ICAO were compared with those in the normal subjects.
At supine rest, systolic (SBp), diastolic (DBp) and mean blood pressure (MBp) in ICAO were 145±21, 85±11 and 105±12mmHg, respectively, and these were higher than the result for normal subjects (130±18, 72±9 and 90±10mmHg) (p<0.05). However, there was no difference between ICAO and normal subjects in the other parameters: heart rate (HR), pulse pressure (pp), cardiac index (CI), stroke index (SI) and total peripheral vascular resistance index (TPRI) in ICAO and normal subjects were 74±12 Vs 68±9 beats/min, 61±20 Vs 58±13mmHg, 2.33±V0.68 s 2.23±0.35L/min/M2, 32.0±10.0 Vs 33.4±6.4ml/beat/M2 and 3860±1162 Vs 3354±640 dynes. sec.cm-5/M2, respectively. Hemodynamic changes induced by the tilt were represented as a percentile ratio of the value after tilt to that at supine rest, and those changes were compared between the two groups. Falls after tilt of SBp (-11.9±10.3%), DBp (-2.9±7.1%), MBp (-7.2±8.0%) and pp (-26.0±10.3%) in ICAO were greater than those in normal subjects (+1.0±5.5%, +3.7±6.9%, +3.3±6.7% and -4.6±10.8%) (p<0.05). Increase after tilt of HR in ICAO (+12.7±11.0%) was greater than that in normal subjects (+2.6±5.8%) (p<0.01). Falls of CI (-16.8±13.3%) and SI (-25.8±12.1%) in ICAO were greater than those in normal subjects (-3.3±12.6% and -6.4±10.2%) (p<0.01). However, changes of TPRI in ICAO (+13.6±18.6%) were not more significant than those in normal subjects (+7.3±15.5). These difference of hemodynamic responses between the two groups became progressively greater as elapesed time after tilt increased.
The patients with ICAO were classified into two groups according to their activity of daily life (ADL) and clinical features. The two groups were poor ADL (ADL score≤5) and good ADL (ADL score>5). When the hemodynamic responsiveness to tilt in the two groups was compared, falls of SBp, DBp and MBp were significantly greater in the poor ADL group than in the good ADL group (p<0.05).
These results indicate that patients with ICAO have orthostatic dysregulation; moreover, the poor ADL group had more distinct orthostatic dysregulation than the good ADL group. Response of HR and TPRI to tilt suggests that the increased blood pressure falls after tilt in patients with ICAO may be related to loss of elasticity of blood-vessels in systemic circulation. However, there remains the possibility that central nervous control may partially affect these orthostatic dysregulations. These abnormalities may contribute in part to the pathophysiological characteristics of patients with ICAO; furthermore, they may affect the prognosis or clinical features.