Prediction of Cerebral Hyperperfusion Syndrome with Velocity Blood Pressure Index

Background：Cerebral hyperperfusion syndrome is an important complication of carotid endarterectomy （CEA）.An 〉 100% increase in middle cerebral artery velocity （MCAV） after CEA is used to predict the cerebral hyperperfusion syndrome （CHS） development,but the accuracy is limited.The increase in blood pressure （BP） after surgery is a risk factor of CHS,but no study uses it to predict CHS.This study was to create a more precise parameter for prediction of CHS by combined the increase of MCAV and BP after CEA.Methods：Systolic MCAV measured by transcranial Doppler and systematic BP were recorded preoperatively;30 min postoperatively.The new parameter velocity BP index （VBI） was calculated from the postoperative increase ratios of MCAV and BE The prediction powers of VBI and the increase ratio of MCAV （velocity ratio [VR]） were compared for predicting CHS occurrence.Results：Totally,6/185 cases suffered CHS.The best-fit cut-off point of 2.0 for VBI was identified,which had 83.3% sensitivity,98.3% specificity,62.5% positive predictive value and 99.4% negative predictive value for CHS development.This result is significantly better than VR （33.3%,97.2%,28.6% and 97.8%）.The area under the curve （AUC） of receiver operating characteristic：AUCvBI =0.981,95% confidence interval [CI] 0.949-0.995;AUCvR =0.935,95% CI 0.890-0.966,P =0.02.Conclusions：The new parameter VBI can more accurately predict patients at risk of CHS after CEA.This observation needs to be validated by larger studies.

Risk factors of postoperative cerebral hyperperfusion syndrome and its relationship with clinical prognosis in adult patients with moyamoya disease

Background To investigate the incidence,risk factors,and clinical prognosis of cerebral hyperperfusion syndrome(CHS)after superficial temporal artery-middle cerebral artery anastomosis combined with encephalo-duro-arterio-synangiosis(STA-MCA/EDAS)in adult patients with moyamoya disease(MMD).Methods The clinical data of 160 adult patients with MMD treated by STA-MCA/EDAS from January 2016 to January 2017 were retrospectively analyzed.According to CHS diagnosis,MMD patients were divided into CHS and non-CHS group.Univariate and multivariate analysis of risk factors and Kaplan-Meier curve of stroke-free survival for CHS were performed.Results A total of 12 patients(7.5%)developed postoperative CHS,of which 4 patients(2.5%)presented with cerebral hemorrhage.Univariate and multivariate analysis showed moyamoya vessel on the surgical hemisphere(OR=3.04,95%CI=1.02-9.03,P=0.046)and left operated hemisphere(OR=5.16,95%CI=1.09-21.34,P=0.041)were independent risk factors for CHS.The other variables,such as age,gender,presentation,hypertension,diabetes,smoking,mean mRS score on admission,modified Suzuki stage and pre-infarction stage on surgical hemisphere,and bypass patency,had no association with postoperative CHS(P>0.05).At final follow-up with average 38 months,there were 18 out of 133 patients(13.5%,4.91%per person year)presented with newly developed complications.There was no significant difference between newly developed complications,mean mRS scores,and Kaplan-Meier curve of stroke-free survival in patients with and without CHS(P>0.05).Conclusion The concentration of moyamoya vessels and left operated hemisphere was independent risk factors for CHS,which could not affect the clinical prognosis if treated timely and properly.The current study offers a new perspective of moyamoya vessels and supporting data for choosing MMD candidates on cerebral revascularization.

Excessive portal flow causes graft failure in extremely small-for-size liver transplantation in pigs

AIM： To evaluate the effects of a portocaval shunt on the decrease of excessive portal flow for the prevention of sinusoidal microcirculatory injury in extremely smallfor-size liver transplantation in pigs. METHODS： The right lateral lobe of pigs, i.e. the 25% of the liver, was transplanted orthotopically. The pigs were divided into two groups： graft without portocaval shunt （n = 11） and graft with portocaval shunt （n = 11）. Survival rate, portal flow, hepatic arterial flow, and histological findings were investigated. RESULTS： In the group without portocaval shunt, all pigs except one died of liver dysfunction within 24 h afcer transplantation. In the group with portocaval shunt, eight pigs survived for more than 4 d. The portal flow volumes before and after transplantation in the group without portocaval shunt were 118.2±26.9 mL/min/100 g liver tissue and 270.5±72.9 ml./min/100 g liver tissue, respectively. On the other hand, in the group with portocaval shunt, those volumes were 124.2±27.8 ml./ min/100 g liver tissue and 42.7±32.3 mL/min/100 g liver tissue, respectively （P〈0.01）. As for histological findings in the group without portocaval shunt, destruction of the sinusoidal lining and bleeding in the peri-portal areas were observed afl：er reperfusion, but these findings were not recognized in the group with portocaval shunt. CONCLUSION： These results suggest that excessive portal flow is attributed to post transplant liver dysfunction after extreme small-for-size liver transplantation caused by sinusoidal microcirculatory injury.