Improvement in Cerebral Hemodynamics After Carotid Angioplasty
ABSTRACT Carotid percutaneous transluminal angioplasty ( PTA) may offer an alternative treatment to carotid endarterectomy. However, in contrast to carotid endarterectomy, which has been shown to normalize impaired cerebral hemodynamics, the effects of carotid PTA are unknown. Therefore, we prospectively studied the effect of carotid PTA on both perioperative and postoperative cerebral hemodynamics.
Eleven patients undergoing carotid PTA for symptomatic carotid artery stenosis were prospectively studied. Transcranial Doppler recordings from the ipsilateral middle cerebral artery (MCA) were performed during the procedure. In addition, MCA blood flow velocity and CO2 reactivity were determined before PTA and at 2 days, 1 month, and 6 months after procedure. The results were compared with those in 11 similar patients undergoing carotid endarterectomy in whom measurements were performed before and 1 month after the operation.
During carotid PTA, in 2 of 11 patients during passage of the balloon catheter through the stenosis, MCA blood flow velocity fell transiently. In 6 of 11 patients there was a reduction in flow velocity (>50%) during balloon deflation, but this lasted only a few seconds. After the procedure there was a significant improvement in ipsilateral hypercapnic reactivity: preoperative value, 59.8+/-42.2% (mean+/-SD); 2 days, 77.9+/-31.4%; 1 month, 88.7+/-45.0%; 6 months, 89.8+/-33.9%; and (ANOVA P=.003) preoperative value versus 1 month, P<.02; versus 6 months, P<.02. In all cases in which reactivity was significantly impaired preoperatively, it returned to the normal range. Pulsatility index also increased significantly: preoperative value, 0.827+/-0.251 (mean+/-SD); 2 days, 0.992+/-0.262 (P=.002). Contralateral MCA hypercapnic reactivity also improved after carotid PTA. There was a similar improvement in ipsilateral hypercapnic reactivity after carotid endarterectomy.
Carotid PTA results in a normalization of impaired hemodynamics, as assessed by CO2 reactivity. The degree of improvement is similar to that seen after carotid endarterectomy.
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ABSTRACT: Purpose: To study the influence of stents positioned at various locations in a physiological model of the carotid artery on the flow behaviour. Methods: Wallstents (Boston Co.) were positioned in silicon models of the carotid artery at various locations: entirely in the internal carotid artery (ICA), in the ICA extending partially and completely into the bulb, and in the ICA extending completely into the commun carotid artery (CCA). Measurements were performed with Laser-Doppler-Anemometry (LDA) and an intravascular US-Doppler-device (Flowire). Under pulsatile flow conditions (Re= 250 ; flow 0,431 l/min ; flow rate ratio ICA:ECA = 70:30 ) measurements were performed in haemodynamically relevant cross-sections. The hemodynamic changes were analysed with 1D flow profiles. Results: With the stent in the ICA, no changes of the normal flow-profile were seen. For the stents positioned in the ICA and extending partially and completely into the CCA, the flow behavior was affected by the resistance of the mesh graft to the flow in the external carotid artery (ECA). Significant disturbances were seen in the ICA and ECA, and the flow rate ratio of the ICA:ECA shifted from 70:30 to 71.3:28.7 and from 70:30 to 75.1:24.9. With the stent placed in the ICA extending completely into the CCA, the flow rate ratio of the ICA:ECA shifted from 70:30 to 72.4:27.6. There were no notable flow changes in the ICA. There was a clear diminishing of the seperation zones in the ECA. Conclusions: Anatomically correctly postioned stents do not lead to significant disturbances in the ICA. In the ECA, depending on the position of the stent, the physiological flow was considerably disturbed when any part of the stent covered the outflow of the vessel. Significant disturbances were seen when the stent was positioned in the bulb.
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ABSTRACT: A patient who lost consciousness and had a convulsion caused by brain ischemia during balloon inflation in connection with percutaneous transluminal angioplasty was successfully treated with a continuous-perfusion dilatation catheter without complications.American Journal of Neuroradiology 05/1997; 18(4):696-8. · 3.68 Impact Factor