The Relationship between between Blood Pressure and Cerebral Haemodynamics and the Ischemic Cerebral Events in Carotid Stenosis Patients
|School||Xinjiang Medical University|
|Keywords||carotid stenosis haemodynamics stroke TIA hypertension|
Objective: Hypertension had close relationship with cerebral haemodynamics and ischemic cerebral events in carotid stenosis patients. In order to investigated the ideal blood pressure to prevent ischemic cerebral events(included transient ischemic cerebral attack , TIA; and ischemic cerebral stroke , ICS), we studied the relationship between blood pressure and cerebral haemodynamics / ischemic cerebral events. Methods: The 330 recruited patients with carotid artery stenosis were hospital patients from the first affiliated hosipital of the Xingjiang Medical University and the Friendship Hosipital in Urumqi during January, 2006 to June, 2008, which included 74 nomoraltensive patients and 256 hypertensive patients. Then we explored the relationship between blood pressure and cerebral haemodynamics / ischemic cerebral events. On one hand, on cross-sectional research, we explored the relationship in the hypertensive patients (N=330, nomortensive patients= 74. hypertensive patients= 256). On thd other hand, on prosepective study, we made an analisis of the relationship between the changes of blood pressure and haemodynamics(N=72 ), and the correlation between the blood pressure and ischemic cerebral events(visited patients=308, the miss patients=7, the carotid stent implantations patients= 15). All people were checked the blood pressure and the carotid haemodynamics, and 95 people were checked the cerevral haemodynamics by transcranial Doppler (TCD), then we recorded all the data and their other information. The carotid stenosis grades were calculated by color doppler ultrasound, at the same time, the carotid and cerebral haemodynamics were checked by color doppler ultrasound and TCD, respectively. Firsly, we compared the haemodynamics parameters and the ischemics cerebral events inciendences among ever SBPgroups and DBP groups. Then, we compared the changes in carotid haemodynamics parameters among three blood pressure changing groups, after antihypertensive therapy. At last, we the ischemics cerebral event incidence among the SBP groups ar betweent the two DBPgroups, ant make Logestic analysis about the relative risk of he factor of blood pressure for ischemics cerebral event.Results: 1) Haemodynamics parameters indicated that: the main influence factor of haemodynamics ablormality is carotid stenosis grade. Morever under the same stenosis grade, the increasing blood pressure would accelerater the abnormality. The blood flow velocities would keep their biggest at SBP 100 to 120mmHg and DBP of 60 to 90mmHg. Besides that, SBP of 100to 140 mmHg would keep the cerebral blood flow stability and reduce the incidence of abnormal velocity to the tiniest in the main patients. The abnormal velocity at SBP of 100 to 120mmHg and SBP of 121 to 140mmHg were abnormal slow-velocity and abnormal fast-velocity respectively. On the other side, DBP had no effect on the cerebral blood flow velocity. 2) The ischemeics cerebral events indicated that: nether SBP increaseing or DBP increasing would be the hazard factor of ischemics cerebral events. The biggest morbidity of past stroke or TIA was appeared at SBP of 140 to 180 mmHg, and the smallest past stroke morbidity was at SBP of 100 to 120 mmHg, while, the smallest morbidity of past stroke was at SBP of 100 to 140 mmHg. At the same time, the biggest risk of TIA was displayed at DBP of 91 to 120mmHg, and the slimmest one was appeared at DBP of 60 to 90 mmHg. However, there was no relationship between DBP and past stroke incidence. After antihypertensive treatment, the blood flow velocities increase significantly in the blood pressure decreasing group. Compared with SBP of 90 to 120mmHg group, the≥140mmHg group has the biggest risk for ischemics cerebral event. However there was no difference between SBP of 121to140mmHg and 100 to 120mmHg group. Althose, there was no difference for the ischemics cerebral event mordibility between DBP of 81to 90mmHg and 60 to 80mmHg group, but the latter group had slightly smaller TIA relapse rate.Conclusion: if there was no different significently in carotid stenosis grade, lowing SBP at 100 to 140mmHg could help increasing cerebral blood flow and preventing the incidence of ischemic cerebral events. In order to keep the ability of cerebral blood flow and to prevent the ischemic cerebral event, it is better to maintin the SBP of 100 to 120mmHg or 121 to 140mmHg, according to cerebral blood velocity faster or slower on TCD. DBP fluctuating between 60 to 90mmHg had no affects on ischemic cerebral events, but it could accelerate the carotid blood flow. If patients could torlerate, DBP of 60 to 80mmHg would help to reduce the TIA relapse rate.