History of Carotid Artery Reconstruction around the World and in Japan

Since ancient times, physicians have been aware of correlations between the carotid artery and consciousness; however, carotid stenosis was only recently identified as the cause of atherothrombotic ischemic stroke. In 1658, Wepfer described the first suggestion of a link between symptoms of cerebral arterial insufficiency and carotid pathology. In 1951, Fisher reported details of the symptoms and pathological findings and emphasized that cervical atheromatous lesions induced cerebral infarction with various symptoms. The beginning of carotid artery surgery was ligation of the carotid artery for neck or head injury, but surgeons were aware that this operation induced cerebral symptoms due to lack of blood supply. Carotid endarterectomy (CEA) was first reported by Eastcott et al. in 1954, and in Japan, Kimoto performed a successful CEA in 1962. In 1979, percutaneous transluminal angioplasty (PTA) was performed for patients with fibromuscular dysplasia, and then, carotid artery stenting (CAS) was first performed in 1989 by Mathias. In Japan, Kuwana et al. were the first to perform carotid PTA, in 1981, whereas Yamashita et al. performed the first CAS in 1997. Yoshimura et al. proposed staged carotid stenting to prevent hyperperfusion syndrome. Some issues in carotid reconstruction are still debated today, which include conventional (standard) CEA versus the eversion technique, CEA versus CAS versus medical therapy, and medical economic problems. In the future, we must continue to develop more effective, safer, and less expensive therapeutic methods to prevent carotid stroke, carrying on the efforts of the ancient peoples who pioneered this research.

Vasoconstriction and hyperperfusion syndrome after carotid artery stenting

Background

Common complications of carotid artery stenting (CAS) are cerebral ischemia and hyperperfusion syndrome. To date, only a few cases of late-onset cerebral vasoconstriction occurring several hours after CAS have been reported. However, there are no reports of developed vasoconstriction and hyperperfusion syndrome.

Case presentation

A 79-year-old man developed vasoconstriction 1 day after carotid artery stenting. Vasoconstriction improved immediately with glucocorticoid. However, a week later, the patient developed hyperperfusion syndrome.

Conclusions

Postoperative vasoconstriction and hyperperfusion syndrome is an unrecognized complication and surgeons should be aware of it.

Dexmedetomidine Combined With Butorphanol or Sufentanil for the Prevention of Post-operative Nausea and Vomiting in Patients Undergoing Microvascular Decompression: A Randomized Controlled Trial

Background: Patients undergoing microvascular decompression are often accompanied with high risk of post-operative nausea and vomiting (PONV). In this study, we compare the antiemetic efficacy of butorphanol or sufentanil combined with dexmedetomidine in patients undergoing microvascular decompression.

Methods: Patients undergoing microvascular decompression were randomized into two groups. The primary outcome was the occurrence and severity of PONV during the 72 h after surgery. Secondary outcomes included levels of pain intensity and sedation and consumption of opioids at 1, 2, 6, 12, 24, 48, and 72 h after surgery. We also recorded the intraoperative hemodynamics, consumption of narcotic drugs, operation and anesthesia time, estimated blood loss, infusion volume and urine output, requirements of rescue antiemetics or analgesics, the satisfaction scores of patients and surgeons, complications, and length of stay.

Results: The overall incidence rates of nausea and vomiting during the 72 h after surgery were significantly reduced in group DB (76.00 and 44.00% in group DS vs. 54.17% and 22.92% in group DB, P < 0.05). Patients in group DB had a lower incidence of nausea than those in group DS at intervals of 1–6 and 6–24 h (P < 0.05). However, patients in group DB had a lower incidence of vomiting than those in group DS only at intervals of 1–6 h (P < 0.05). Similarly, the number of patients requiring rescue antiemetics was also significantly reduced in group DB compared with that in group DS at intervals of 1–6 h (P < 0.05). The number of patients experiencing moderate to severe PONV was comparable between the two groups during 72 h after surgery (P > 0.05). The consumption of opioid morphine equivalent was significantly reduced in group DB (P < 0.05). Compared with those in group DS, the satisfaction scores of both patients and surgeons were significantly increased in group DB (P < 0.05).

Conclusion: Butorphanol combined with dexmedetomidine could reduce early PONV and the number of patients requiring rescue antiemetics, especially at intervals of 1–6 h, while the satisfaction scores of both patients and surgeons were significantly increased.

Efficacy of near-infrared spectroscopy cerebral oximetry on detection of critical cerebral perfusion during carotid endarterectomy under regional anesthesia

Summary: Background: Patients undergoing carotid endarterectomy (CEA) may suffer from cerebral hypoperfusion during the carotid cross-clamping. Near-infrared spectroscopy cerebral oximetry (NIRS) is a non-invasive method of regional cerebral oxygen saturation measurement reflecting changes in cerebral blood flow during CEA. The main goal of the study was to evaluate the accuracy of the NIRS in detecting cerebral hypoperfusion during CEA under regional anesthesia (RA) and compare it with awake neurological testing. Patients and methods: A prospective observational study of 28 patients that underwent CEA in RA and manifested neurologic deficits, and 28 consecutive controls from a tertiary and referral center, was performed. All patients were monitored with NIRS cerebral oximetry and awake testing as the control technique. Subsequently, operating characteristic curve and Cohen’s kappa coefficient were determined to evaluate the reliability of the monitoring test. Results: NIRS presented a sensitivity of 27.3% and a specificity of 89.3% in comparison to awake testing. Receiver operating characteristic (ROC) curve analysis demonstrated that a decrease of at least 20% in cerebral oxygen saturation is the best threshold to infer cerebral hypoperfusion. However, the respective area under the curve (AUROC) was 0.606 (95% CI: 0.456–0.756, P = 0.178) with a calculated Cohen’s kappa of 0.179, P = 0.093. Regarding 30-days outcomes, only awake testing has shown significant associations with stroke and postoperative complications ( P = 0.043 and P = 0.05), which were higher in patients with post-clamping neurologic deficits. Conclusions: NIRS demonstrated a reduced discriminative capacity for critical cerebral hypoperfusion, and does not seem to add substantial clinical benefits to the awake test.

Effectiveness of staged angioplasty for avoidance of cerebral hyperperfusion syndrome after carotid revascularization

OBJECTIVE

Cerebral hyperperfusion syndrome (CHS) is a serious complication after carotid artery stenting (CAS). Staged angioplasty (SAP)-i.e., angioplasty followed by delayed CAS-has been reported as a potential CHS-avoiding procedure. The purpose of this study was to clarify the effectiveness of SAP in avoiding CHS after carotid revascularization for patients at high risk for this complication.

METHODS

The authors retrospectively studied cases involving patients at high risk for CHS from 44 Japanese centers who were scheduled for SAP, regular CAS, angioplasty, or staged procedures other than SAP between October 2007 and March 2014. They investigated the rate of CHS in the population scheduled for SAP or regular CAS, and for safety analysis, the composite rate of transient ischemic attack (TIA) and ischemic stroke in the population eventually receiving SAP or regular CAS.

RESULTS

Data from a total of 525 patients (532 lesions, mean age 72.5 ± 7.5 years, 74 women ) were analyzed. Scheduled procedures included SAP for 113 lesions and regular CAS for 419 lesions. The rate of CHS was lower in the SAP group than in the regular CAS group (4.4% vs 10.5%, p = 0.047). Multivariate analysis showed that SAP was negatively related to CHS (OR 0.315; 95% CI 0.120-0.828). In the population eventually receiving SAP (102 lesions) or regular CAS (428 lesions), the composite rate of TIA and ischemic stroke was comparable between the SAP group and the regular CAS group (9.8% vs 9.3%).

CONCLUSIONS

SAP may be an effective and safe carotid revascularization procedure to avoid CHS.

Efficacy of superficial temporal artery-middle cerebral artery double bypass in patients with hemorrhagic moyamoya disease: surgical effects for operated hemispheric sides

The effects of superficial temporal artery to middle cerebral artery (STA-MCA) double bypass on recurrent hemorrhage in the operated hemisphere in hemorrhagic moyamoya disease (HMD) have not been clearly demonstrated. This study evaluated the effectiveness of STA-MCA double bypass in the prevention of further hemorrhagic or ischemic events in the operated hemispheric sides in comparison to the conservatively treated non-operated sides. We retrospectively analyzed 52 hemispheres of 36 patients with adult-onset HMD treated with STA-MCA double bypass. Twenty and 16 patients underwent unilateral (unilateral group) and bilateral (bilateral group) surgery, respectively. In addition, the perioperative and long-term outcomes of the 52 operated sides and 20 non-operated sides in the unilateral group were compared. All bypass surgeries were successful, but 21% of the operated sides showed hyperperfusion as estimated by our methods. Perioperative mortality and morbidity rate were 0% and 5.6%, respectively. Concerning long-term follow-up, the annual rebleeding rate (ARR) in the unilateral and bilateral group was 2.7% and 2.6%/person-year, respectively (p = 0.256). The ARR in the operated and non-operated sides was 1.1% and 1.8%/side-year, respectively (p = 0.163). Two of 20 non-operated sides suffered from ischemic infarction during the follow-up period, while none of the 52 operated sides experienced ischemic events (p < 0.05). Although the long-term rebleeding rate in the operated hemisphere tended to be lower after STA-MCA double bypass compared with that in the non-operated hemisphere, the difference was not statistically significant. In conclusion, while STA-MCA double bypass could not clearly prevent rebleeding, it can prevent further ischemic attacks in patients with HMD.

Hybrid Surgery for Nontaper or Nonstump Lesions in Symptomatic Subacute or Chronic Internal Carotid Occlusion: A Better Solution

BACKGROUND

Internal carotid artery occlusion (ICAO) causes transient ischemic attack and cerebral infarction. ICAO management remains clinically challenging. We discuss a hybrid treatment combining carotid endarterectomy and endovascular intervention (E-I) for patients with nontaper or nonstump lesions of symptomatic ICAO.

METHODS

We treated 32 patients with consecutive nontaper or nonstump ICAO with neurological symptoms with hybrid treatment or E-I. We analyzed the epidemiology, symptoms, angiographic morphology, technical success rate, and perioperative complications.

RESULTS

Of the 32 patients, 17 were treated with hybrid surgery and 15, E-I. The demographic data and lesion characteristics were similar between the 2 groups. The overall recanalization success rate was 71.9%. The rate for hybrid surgery was better than that for E-I (88.2% vs. 53.3%). The postoperative cerebral hyperperfusion rate showed no difference between the 2 groups (11.8% vs. 6.7%). Ipsilateral cerebral perfusion improved after treatment. The mean transition time and time to peak were greater than normal (normal values, <6 seconds and <8 seconds, respectively). Both increased significantly after treatment (mean transition time, 11.30 seconds vs. 7.25 seconds; time to peak, 19.30 seconds vs. 15.50 seconds). The incidence of perioperative complications from hybrid surgery was less than that with E-I (5.9% vs. 40.0%). Recurrent cerebrovascular events (5.9% vs. 13.3%) and the 3-month modified Rankin scale score (2.76 ± 0.66 vs. 2.93 ± 0.70) did not differ between the 2 groups.

CONCLUSIONS

Recanalization of nontaper or nonstump ICAO with hybrid treatment was more successful than that with E-I, with fewer perioperative complications. The carotid endarterectomy procedure enables easier wire crossing across the occlusion and reduces potential technology-related complications by requiring a shorter lesion and fewer dissections and minimizing the effect of calcification.

Predicting the Occurrence of Hemorrhagic Cerebral Hyperperfusion Syndrome Using Regional Cerebral Blood Flow After Direct Bypass Surgery in Patients with Moyamoya Disease

OBJECTIVE

Superficial temporal artery-middle cerebral artery anastomosis is an established treatment for moyamoya disease. However, hemorrhagic cerebral hyperperfusion syndrome (CHS) leads to poor outcomes. This study aimed to identify predictors of hemorrhagic CHS based on regional cerebral blood flow (rCBF) in patients with moyamoya disease.

METHODS

The study included 251 hemispheres in 155 patients with moyamoya disease who underwent preoperative and postoperative rCBF measurements and superficial temporal artery-middle cerebral artery double anastomosis. We used rCBF increase rate for predicting hemorrhagic CHS. rCBF increase rate was calculated by 2 methods. In method 1, the rCBF value on the operated side was compared with the rCBF value on the nonoperated side. In method 2, the postoperative rCBF value on the operated side was compared with the preoperative rCBF value on the operated side. Patients were classified into 4 groups according to rCBF increase rate to predict risk of hemorrhagic CHS.

RESULTS

Hemorrhagic CHS occurred in 7 (2.8%) hemispheres (no children). Severe hemorrhagic CHS occurred in only 1 (0.4%) hemisphere. Hemorrhagic CHS was observed in patients with ≥30% rCBF increase according to method 1 and ≥50% rCBF increase according to method 2 and was most frequently noted in ≥100% rCBF increase.

CONCLUSIONS

Predictors for hemorrhagic CHS were ≥30% rCBF increase when using method 1 and ≥50% increase when using method 2.

Factors of Delayed Hyperperfusion and the Importance of Repeated Cerebral Blood Flow Evaluation for Hyperperfusion After Direct Bypass for Moyamoya Disease

OBJECTIVE

Postoperative hyperperfusion is an important complication after direct bypass for moyamoya disease, which sometimes occurs late after initial postoperative cerebral blood flow (CBF) measurement. This study aimed to clarify the incidence of hyperperfusion with management using postoperative continuous sedation and repeated postoperative CBF measurement and to identify factors associated with delayed hyperperfusion.

METHODS

This retrospective study evaluated 72 consecutive hemispheres in 56 adult Japanese patients with moyamoya disease who underwent direct bypass. Postoperative continuous sedation was routinely administered based on CBF evaluation. First, the incidence of symptomatic hyperperfusion was investigated. Second, radiologic hyperperfusion (RHP), which was strictly defined as >30% increase in CBF compared with the contralateral side, and factors associated with delayed RHP were statistically analyzed.

RESULTS

Postoperative symptomatic hyperperfusion occurred in 3 hemispheres (4.2%), including subarachnoid hemorrhage in 1 hemisphere (1.4%). RHP immediately after surgery was identified in 16 hemispheres (22.2%). In 8 hemispheres (11.1%), RHP appeared or worsened several days after initial CBF study. In univariate logistic regression analysis, decreased preoperative cerebral vasoreactivity was significantly associated with delayed RHP.

CONCLUSIONS

The incidence of symptomatic hyperperfusion was 4.2% with management. Delayed hyperperfusion was significantly associated with decreased cerebral vasoreactivity. Therefore, repeated CBF measurements evaluating preoperative cerebral vasoreactivity may decrease complications.

Development of a Preoperative Simulation Technique for Carotid Endarterectomy in Patients with Contrast Contraindications

BACKGROUND

Vascular and osteological parameters, such as the heights of the carotid bifurcation and distal end of the plaque, are important preoperative considerations for patients undergoing carotid stenosis procedures, such as carotid endarterectomy. However, for patients with contraindications to contrast media, such as allergies or nephropathies, 3-dimensional computed tomography angiography (3D-CTA) is unavailable, and preoperative evaluation remains challenging. In the present study, we aimed to develop a preoperative simulation for use in patients with contrast-contraindicated carotid stenosis.

METHODS

Images from noncontrast neck computed tomography scans and magnetic resonance imaging obtained without the Leksell stereotactic frame were uploaded to GammaPlan. Following delineation of various structures, preoperative simulations were performed to determine the relationships between vascular and osteological structures. We applied this technique in 10 patients with carotid stenosis to verify the accuracy of the simulation.

RESULTS

In all patients, the GammaPlan simulation successfully visualized the heights of the carotid bifurcation and distal end of the plaque without the use of contrast medium. Furthermore, information regarding the location of internal arterial structures, such as calcifications and unstable plaques, could be incorporated into GammaPlan images. We verified simulation accuracy by comparing the simulation results with 3D-CTA and operative findings.

CONCLUSIONS

Simulations created using GammaPlan can be used to obtain accurate vascular and osteological information regarding the heights of the carotid bifurcation and distal end of the plaque, without the use of contrast medium. The reconstruction of delineated structures using this technique may be effective for preoperative evaluation in patients with contrast-contraindicated carotid stenosis.

Quantitative magnetic resonance angiography as a potential predictor for cerebral hyperperfusion syndrome: a preliminary study

OBJECTIVE

Cerebral hyperperfusion syndrome (CHS) is a rare but devastating complication of carotid endarterectomy (CEA). This study sought to determine whether quantitative hemodynamic assessment using MR angiography can stratify CHS risk.

METHODS

In this prospective trial, patients with internal carotid artery (ICA) stenosis were randomly selected for pre- and postoperative quantitative phase-contrast MR angiography (QMRA). Assessment was standardized according to a protocol and included Doppler/duplex sonography, MRI, and/or CT angiography and QMRA of the intra- and extracranial supplying arteries of the brain. Clinical and radiological data were analyzed to identify CHS risk factors.

RESULTS

Twenty-five of 153 patients who underwent CEA for ICA stenosis were randomly selected for pre- and postoperative QMRA. QMRA data showed a 2.2-fold postoperative increase in blood flow in the operated ICA (p < 0.001) and a 1.3-fold increase in the ipsilateral middle cerebral artery (MCA) (p = 0.01). Four patients had clinically manifested CHS. The mean flow increases in the patients with CHS were significantly higher than in the patients without CHS, both in the ICA and MCA (p < 0.001). Female sex and a low preoperative diastolic blood pressure were the clearest clinical risk factors for CHS, whereas the flow differences and absolute postoperative flow values in the ipsilateral ICA and MCA were identified as potential radiological predictors for CHS.

CONCLUSIONS

Cerebral blood flow in the ipsilateral ICA and MCA as assessed by QMRA significantly increased after CEA. Higher mean flow differences in ICA and MCA were associated with the development of CHS. QMRA might have the potential to become a noninvasive, operator-independent screening tool for identifying patients at risk for CHS.

Intracerebral Hemorrhage Caused by Cerebral Hyperperfusion after Superficial Temporal Artery to Middle Cerebral Artery Bypass for Atherosclerotic Occlusive Cerebrovascular Disease

Few papers have reported detailed accounts of intracerebral hemorrhage caused by cerebral hyperperfusion after superficial temporal artery to middle cerebral artery bypass (STA-MCA) bypass for atherosclerotic occlusive cerebrovascular disease. We report a case of vasogenic edema and subsequent intracerebral hemorrhage caused by the cerebral hyperperfusion syndrome (CHS) after STA-MCA bypass for atherosclerotic occlusive cerebrovascular disease disease without intense postoperative blood pressure control. A 63-year-old man with repeating left hemiparesis underwent magnetic resonance angiography (MRA), which revealed right internal carotid artery (ICA) occlusion. We performed a double bypass superficial temporal artery (STA)–middle cerebral artery (MCA) bypass surgery for the M2 and M3 branches. While the patient’s postoperative course was relatively uneventful, he suffered generalized convulsions, and computed tomography revealed a low area in the right frontal lobe on Day 4 after surgery. We considered this lesion to be pure vasogenic edema caused by cerebral hyperperfusion after revascularization. Intravenous drip infusion of a free radical scavenger (edaravone) and efforts to reduce systolic blood pressure to <120 mmHg were continued. The patient experienced severe left hemiparesis and disturbance of consciousness on Day 8 after surgery, due to intracerebral hemorrhage in the right frontal lobe at the site of the earlier vasogenic edema. Brain edema associated with cerebral hyperperfusion after STA-MCA bypass for atherosclerotic occlusive cerebrovascular disease should be recognized as a risk factor for intracerebral hemorrhage. The development of brain edema associated with CHS after STA-MCA bypass for atherosclerotic occlusive cerebrovascular disease requires not only intensive control of blood pressure, but also consideration of sedation therapy with propofol.

Perioperative and Long-term Outcomes of Carotid Endarterectomy for Japanese Asymptomatic Cervical Carotid Artery Stenosis: A Single Institution Study

As the recently developed medical treatments for asymptomatic cervical carotid artery stenosis (ACCAS) have shown excellent stroke prevention, carotid endarterectomy (CEA) should be carried out for more selected patients and with lower complication rates and better long-term outcomes. We have performed CEA for Japanese ACCAS patients with a uniform surgical technique and strict perioperative management. In this study, we retrospectively investigated the perioperative complications and long-term outcomes of our CEA series. A total of 147 CEAs were carried out in 139 Japanese ACCAS patients. All patients were routinely checked for their cardiac function and high risk coronary lesions were preferentially treated before CEA. All CEAs were performed under general anesthesia using a shunt system. The postoperative cerebral blood flow was routinely measured under continued sedation to prevent postoperative hyperperfusion. The 30-day perioperative morbidity rate was 2.04%, including a perioperative stroke rate of 0.68%. There were no perioperative deaths. With regard to the long-term outcomes of the 134 followed-up patients, 9 patients were dead and 5 patients suffered from strokes, including 2 patients with ipsilateral hemispheric ischemia. The annual rates of death, all stroke and ipsilateral ischemic stroke were 1.15%, 0.64%, and 0.25%, respectively. These results showed that the perioperative morbidity and mortality rates of our CEAs were lower than those in the previous large trials. Furthermore, the long-term outcomes of this series were favorable to those reported in the latest medical treatment trials for ACCAS patients. CEA may be useful for preventing ischemic stroke in Japanese ACCAS patients.

Moyamoya disease concurrent with Graves' disease treated by direct bypass: clinical features and treatment strategies

BACKGROUND

Moyamoya disease (MMD) concurrent with Graves' disease (GD) is rare. There is no guideline about optimizing thyroid hormones and the appropriate timing of surgical treatment for MMD with GD.

METHODS

We encountered eight patients with MMD and GD presenting with cerebral ischemia who were treated by direct bypass. Thyroid hormones [free thyroxin (fT4) and free triiodothyronine (fT3)], thyroid-stimulating hormone (TSH), and TSH receptor antibody (TRAb) were measured sequentially. After thyrotoxic conditions were medically optimized, revascularization surgery was performed by superficial temporal artery-middle cerebral artery (STA-MCA) double bypass in all cases. Clinical outcomes were estimated by modified Rankin scale (mRS) at discharge and 3 months after surgery.

RESULTS

In six patients with thyrotoxicosis, the fT4, fT3, and TRAb (range) at the onset of cerebral ischemia were 4.81-10.30 pg/ml, 13.08-31.90 pg/ml, and 3.5-83.8 IU/l, respectively. At surgery, mean (range) fT3 and fT4 were optimized to 3.02 (1.01-4.87) pg/ml and 1.09 (0.41-1.68) ng/dl, respectively. In the thyrotoxic cases, it took 70-310 days (mean, 142 days) to optimize thyroid hormones before surgery. There was no neurological aggravation after surgery, and outcome was excellent at 3 months with mRS scores ≤2 in all cases.

CONCLUSIONS

For MMD concurrent with GD, optimizing thyroid hormones followed by STA-MCA double bypass was successful to prevent cerebral ischemic events.

Omnidirectional retractor-supporting ring as a new device for carotid endarterectomy

In carotid endarterectomy (CEA), the traditional retractors are often difficult to use because they tend to obstruct surgical manipulations, especially in the deep operative field on the rostral side. The authors have invented a new omnidirectional retractor-supporting ring (OD ring) to solve the problems of traditional retractors. The OD ring has an ellipsoid-shaped frame (major axis: 275 mm, minor axis: 192 mm) with 22 equally spaced outward protrusions. Rubber bands from which blunt mini-hooks are hung are twisted around the protrusions. The OD ring was placed on the operative area, and the skin edges were retracted by mini-hooks placed symmetrically. The hooks were moved gradually from the shallow to the deep operative field as surgical dissection continued to expose the carotid bifurcation and distal internal carotid artery (ICA). The OD ring was used in 158 consecutive CEAs in the authors' institute between July 2010 and October 2013. The OD ring provided a flatter surgical field and was less obstructive than traditional retractors, thereby facilitating surgical manipulation in the deep operative field such as at the distal ICA. Furthermore, because of its simpler shape, angiorrhaphy could be conducted more smoothly, with less tangled thread during closure of the arteriotomy. There were no technical complications related to the OD ring. As a new retractor system for CEA, the OD ring is less obstructive and provides a flatter surgical field than traditional retractors, thereby facilitating surgical manipulations in the deep operative field around the distal ICA.

Carotid Revascularization: An Update

Symptomatic extracranial internal carotid artery stenosis poses a high short-time risk of ischemic cerebral stroke, as high as 20% to 30% in the first three months. Timely performed carotid endarterectomy (CEA) has been shown to be highly effective in reducing this risk although, in recent years, there has been great interest in replacing this procedure with less invasive carotid angioplasty and stenting (CAS). In this update we review recent studies and provide recommendations regarding the indications, methods and timing of surgical intervention as well as the anaesthetic management of CEA, and we report on recently published randomized controlled trials comparing CEA to CAS. We also provide recommendations regarding the sometime neglected but important medical management of patients undergoing carotid intervention, including antithrombotic and antihypertension therapy, lipid lowering agents, assistance with smoking cessation, and diabetes control.

Intraoperative assessment of cortical perfusion by indocyanine green videoangiography in surgical revascularization for moyamoya disease

BACKGROUND

Postoperative hyperperfusion is a potential complication of the direct bypass procedure for moyamoya disease (MMD). However, no reliable modality is available yet for the prediction of postoperative hyperperfusion during surgery for MMD. This study aimed to investigate whether semiquantitative analysis of indocyanine green (ICG) videoangiography could contribute to the prediction of postoperative hyperperfusion in MMD.

METHODS

This study included 12 hemispheres from 10 patients who underwent surgical revascularization for MMD. Intraoperative ICG videoangiography was performed before and after a direct bypass procedure. The ICG intensity-time curves were semiquantitatively analyzed to evaluate cortical perfusion by calculating the blood flow index (BFI). Using single-photon emission computed tomography (SPECT), postoperative cerebral blood flow measurements were performed thrice: immediately, and 2 and 7 days after surgery.

RESULTS

BFI significantly increased from 21.3 ± 10.5 to 38.4 ± 20.0 after bypass procedures in all the hemispheres (p < 0.01). The ratio of BFI before and after the bypass procedure was 2.4 ± 2.0, ranging from 0.5 to 8.0. Postoperative hyperperfusion was observed in nine of the 12 operated hemispheres within 7 days after surgery. Of these, three hemispheres developed hyperperfusion immediately after surgery. In the adult cases, the increase in the ratio of BFI after bypass was significantly greater in those who developed hyperperfusion immediately after surgery than in those who did not (6.5 ± 0.5 vs. 1.8 ± 2.1, p < 0.01). In contrast, no significant increase in BFI was observed in the pediatric MMD patients who experienced immediate hyperperfusion. No correlation between the changes in BFI and the occurrence of delayed hyperperfusion was observed.

CONCLUSIONS

Our results suggest that semiquantitative analysis of BFI by intraoperative ICG videoangiography is useful in evaluating changes in cortical perfusion after bypass procedures for MMD and can predict the occurrence of early-onset hyperperfusion in MMD patients after direct bypass.

Stenotic transverse sinus predisposes to poststenting hyperperfusion syndrome as evidenced by quantitative analysis of peritherapeutic cerebral circulation time

BACKGROUND AND PURPOSE

Hyperperfusion syndrome is a devastating complication of carotid stent placement. The shortening of cerebral circulation time after stent placement is seen as a good indicator of the development of hyperperfusion syndrome. The purpose of our study was to evaluate whether patients with ipsilateral transverse sinus stenosis are prone to having shortened cerebral circulation time after stent placement, subsequently leading to the possible development of hyperperfusion syndrome.

MATERIALS AND METHODS

Forty-nine patients with >70% unilateral carotid stenosis undergoing stent placement were recruited for analysis. Group A consisted of patients with a stenotic ipsilateral transverse sinus >50% greater than the diameter of the contralateral transverse sinus; the remaining patients were in group B. Quantitative DSA was used to calculate cerebral circulation time. Cerebral circulation time was defined as the time difference between the relative time to maximal intensity of ROIs in the proximal internal carotid artery and the internal jugular vein. ΔCCT was defined as cerebral circulation time before stent placement minus cerebral circulation time after stent placement. ΔCCT, white matter hyperintensity signals, and sulcal effacement in MR imaging were compared between the 2 groups.

RESULTS

ΔCCT was significantly shorter in group A (0.65 ± 1.3) than in group B (-0.12 ± 1.4). Three patients had white matter hyperintensity signals in group A, and 1 developed hyperperfusion syndrome. Group B showed no MR imaging signs of hyperperfusion syndrome.

CONCLUSIONS

Ipsilateral hypoplastic transverse sinus was associated with prolonged cerebral circulation time before stent placement and greatly shortened cerebral circulation time after stent placement. Inadequate venous drainage might play a role in impaired cerebral autoregulation and might influence the development of poststenting hyperperfusion syndrome.

Stratification of intraoperative ischemic impact by somatosensory evoked potential monitoring, diffusion-weighted imaging and magnetic resonance angiography in carotid endarterectomy with routine shunt use

BACKGROUND

Routine shunting to minimize ischemia during carotid endarterectomy (CEA) is controversial. The aim of this study was to stratify the ischemic parameters associated with CEA and evaluate the effect of routine shunting in attempting to mitigate those ischemia.

METHOD

Data from 248 CEAs with routine shunting were retrospectively evaluated. Our assessment included somatosensory evoked potential (SSEP) amplitude reduction more than 50 % and longer than 5 min (SSEP<50%, >5 min), new postoperative diffusion-weighted imaging lesions (new DWI lesions), and severe stenosis as indicated by reduced ipsilateral middle cerebral artery (MCA) signal on preoperative magnetic resonance angiography (MRA asymmetry), as surrogates of hypoperfusion, microembli, and hemodynamic impairment, respectively.

RESULTS

SSEP<50%, >5 min occurred in 15 % of CEAs during cross-clamping, and shunting reversed the SSEP changes. New DWI lesions were observed in 4.1 %. Pre-clamping the common and external carotid artery during dissection (pre-clamp method) decreased the rate of new DWI lesions compared to without pre-clamping (3.5 % vs. 7.5 %, P = 0.22). Occlusion time was significantly longer in the pre-clamp method than without pre-clamping (P < 0.0001). However, the incidence of SSEP<50%, >5 min was not increased with the pre-clamp method (p = 1.0) when using information regarding SSEP and collaterals to modify the speed of shunt manipulation. MRA asymmetry was identified in 39 CEAs (15.8 %) with correction of asymmetry postoperatively. MRA asymmetry correlated with symptomatic hyperperfusion (P = 0.0034). Only three CEAs had symptomatic hyperperfusion (1.2 %) with minimal symptoms. Ten CEAs sustained transient ischemia, symptomatic hyperperfusion, or 30-day-stroke (composite postoperative ischemic symptoms). Logistic regression analysis confirmed that SSEP<50%, >5 min (p = 0.009), new DWI lesions (p = 0.004) and MRA asymmetry (p = 0.042) were independent predictors of　composite postoperative ischemic symptoms.

CONCLUSIONS

SSEP<50%, >5 min, new DWI lesions, and MRA asymmetry were able to stratify the ischemic impacts in CEA. Meticulous routine shunting could mitigate those appropriately.

Post-carotid endarterectomy cerebral hyperperfusion syndrome : is it preventable by strict blood pressure control?

Objective

Cerebral hyperperfusion syndrome (CHS) is a serious complication after carotid endarterectomy (CEA). However, the prevalence of CHS has decreased as techniques have improved. This study evaluates the role of strict blood pressure (BP) control for the prevention of CHS.

Methods

All 18 patients who received CEA from February 2009 through November 2012 were retrospectively reviewed. All patients were routinely managed in an intensive care unit by a same protocol. The cerebral perfusion state was evaluated on the basis of the regional cerebral blood flow (rCBF) study by perfusion computed tomography (pCT) and mean velocity by transcranial doppler (TCD). BP was strictly controlled (<140/90 mm Hg) for 7 days. When either post-CEA hyperperfusion (>100% increase in the rCBF by pCT or in the mean velocity by TCD compared with preoperative values) or CHS was detected, BP was maintained below 120/80 mm Hg.

Results

TCD and pCT data on the patients were analyzed. Ipsilateral rCBF was significantly increased after CEA in the pCT (p=0.049). Post-CEA hyperperfusion was observed in 3 patients (18.7%) in the pCT and 2 patients (12.5%) in the TCD study. No patients developed clinical CHS for one month after CEA. Furthermore, no patients developed additional neurological deficits related to postoperative cerebrovascular complications.

Conclusion

Intensive care with strict BP control (<140/90 mm Hg) achieved a low prevalence of post-CEA hyperperfusion and prevented CHS. This study suggests that intensive care with strict BP control can prevent the prevalence of post-CEA CHS.

Signal intensity changes for the middle cerebral artery on 3-dimensional time-of-flight magnetic resonance angiography indicate acute hemodynamic changes after carotid endarterectomy

BACKGROUND

For 3-dimensional time-of-flight magnetic resonance angiography (3D-TOF-MRA), the signal intensity (SI) loss depends on the flow velocity. In this study, we aimed to evaluate whether 3D-TOF-MRA could be used as an alternative to single-photon emission computed tomography (SPECT) for assessing the increase in the regional cerebral blood flow (rCBF) after carotid endarterectomy (CEA). To do this, we compared the SI of the middle cerebral artery (MCA) on magnetic resonance angiography (MRA) and the rCBF on SPECT.

METHODS

We enrolled 30 patients with internal carotid artery stenosis. SPECT and MRA were performed before and 3-4 days after CEA. rCBF was assessed using SPECT, and the SI of the MCA was assessed using single-slab 3D-TOF-MRA. Regions of interest were placed in the bilateral middle M1 portions of the MCA on MRA, and their mean SI was measured. The increase ratio of the rCBF on SPECT and the increase ratio of the SI of the MCA on MRA were calculated using the formula: (post-CEA ipsilateral/post-CEA contralateral)/(pre-CEA ipsilateral/pre-CEA contralateral).

RESULTS

A significant correlation was observed between the increase ratio of the rCBF on SPECT and the increase ratio of the SI of the MCA on MRA (r=.894, y=.4863+.5184x, P<.001). All values obtained by MRA were greater than or equal to the SPECT values, indicating that MRA tends to overestimate the post-CEA rCBF increase.

CONCLUSION

Because MRA identified increased rCBF after CEA, we recommend that patients first be screened using MRA.

Semiquantitative analysis of indocyanine green videoangiography for cortical perfusion assessment in superficial temporal artery to middle cerebral artery anastomosis

BACKGROUND

Postoperative hyperperfusion may lead to severe neurological complications after superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis. However, there are no reliable modalities to predict the occurrence of postoperative hyperperfusion during surgery. The purpose of this study is to evaluate whether a semiquantitative analysis of indocyanine green (ICG) videoangiography could be useful in predicting postoperative hyperperfusion after STA-MCA anastomosis.

METHODS

This study included seven patients who underwent STA-MCA anastomosis due to occlusive carotid artery diseases. During surgery, ICG videoangiography was performed before and after bypass procedures, and ICG intensity-time curves were semiquantitatively analyzed to evaluate hemodynamic changes by calculating maximum intensity, time to peak (TTP), and blood flow index (BFI).

RESULTS

Maximum intensity significantly increased from 252.6 ± 132.5 to 351.7 ± 151.9 after bypass (p < 0.001). TTP was significantly shortened from 12.9 ± 4.4 s to 9.8 ± 3.7 s (p < 0.001). Furthermore, BFI significantly increased from 33.9 ± 28.1 to 74.6 ± 88.4 (p < 0.05). Postoperative hyperperfusion was observed in five of seven patients 1 day after surgery. The ratio of BFI before and after bypass procedures was significantly higher in patients with postoperative hyperperfusion than those without, 2.5 ± 1.1 and 1.5 ± 0.4, respectively (p = 0.013).

CONCLUSIONS

These findings suggest that semiquantitative analysis of ICG videoangiography is helpful in predicting occurrence of hyperperfusion after STA-MCA anastomosis in patients with occlusive carotid artery diseases.

Subclinical ischemia verified by somatosensory evoked potential amplitude reduction during carotid endarterectomy: negative effects on cognitive performance

OBJECT

Although the mechanisms underlying neurocognitive changes after carotid endarterectomy (CEA) are poorly understood, intraoperative ischemia and postoperative hemodynamic changes may play a role.

METHODS

Data from 81 patients who underwent unilateral CEA with routine shunt use for carotid artery stenosis were retrospectively evaluated. These patients underwent neuropsychological examinations (NPEs), including assessment by the Wechsler Adult Intelligence Scale-Third Edition and the Wechsler Memory Scale-Revised before and 6 months after CEA. results of NPEs were converted into z scores, from which pre- and postoperative cognitive composite scores (CSpre and CSpost) were obtained. The association between the change of CS between pre- and postoperative NPEs (that is, CSpost - CSpre [CSpost - pre]) and various variables was assessed. These latter variables included ischemic or hemodynamic parameters such as 1) intraoperative hypoperfusion detected by somatosensory evoked potential (SSEP) change-that is, an SSEP amplitude reduction more than 50% and longer than 5 minutes (SSEP< 50%, > 5 min); 2) new lesions on postoperative diffusion-weighted imaging studies; and 3) preexisting hemodynamic impairment. Paired t-tests of the NPE scores were performed to determine the net effect of these factors on neurocognitive function at 6 months.

RESULTS

A significant CSpost - pre decrease was observed in patients with SSEP< 50%, > 5 min when compared with those without SSEP< 50%, > 5 min (-0.225 vs 0.018; p = 0.012). Multiple regression analysis demonstrated that SSEP< 50%, > 5 min independently and negatively correlated with CSpost - pre (p = 0.0020). In the group-rate analysis, postoperative NPE scores were significantly improved relative to preoperative scores.

CONCLUSIONS

Hypoperfusion during cross-clamping, as verified by SSEP amplitude reduction, plays a significant role in the subtle decline in cognition following CEA. However, this detrimental effect was small, and various confounding factors were present. Based on these observations and the group-rate analysis, the authors conclude that successful unilateral CEA with routine shunt use does not adversely affect postoperative cognitive function.

Cerebral Hyperperfusion Syndrome After Superficial Temporal Artery-middle Cerebral Artery Bypass for Severe Intracranial Steno-occlusive Disease: A Case Control Study

BACKGROUND:

Intracranial stenoses carry increased risk for cerebral ischemia. We perform external carotid-internal carotid (EC-IC) artery bypass in our patients with severe stenosis of the intracranial internal carotid (ICA) or middle cerebral artery (MCA) with impaired cerebral vasodilatory reserve (CVR).

OBJECTIVE:

To evaluate cerebral hemodynamics and cerebral hyperperfusion syndrome (HPS) in patients who develop focal neurological deficits after EC-IC bypass surgery.

METHODS:

Patients with severe intracranial ICA or MCA stenosis and impaired CVR on transcranial Doppler (TCD) derived breath-holding index (BHI) were evaluated with acetazolamide-challenged technetium-99m hexamethylpropyleneamineoxime–single-photon emission computed tomography (SPECT). EC-IC bypass surgery was offered to patients with impaired CVR on SPECT. Close monitoring was performed in patients developing focal neurological deficits within 7 days of surgery.

RESULTS:

Of 112 patients with severe intracranial ICA/MCA stenosis, 77 (69%) showed impaired CVR and 46 (41%) underwent EC-IC bypass. Transient neurological deficits within 7 days of surgery developed in 8 (17%). HPS was confirmed by CT perfusion and/or SPECT in 7 cases. A strong correlation was observed between HPS and preoperative TCD-BHI values (0%, 6.3%, and 41% in patients with BHI 0.3-0.69, 0-0.3 and &lt;0, respectively; P = .012). HPS patients showed more than a 50% increase in MCA flow velocity on TCD (compared with preoperative values) on the operated side (63.3% vs 3.3% on control side, P &lt; .001). Meticulous control of blood pressure and hydration led to rapid and complete resolution of neurological deficits in all cases.

CONCLUSION:

Symptomatic cerebral HPS is common in the early postoperative period after EC-IC bypass surgery. Early diagnosis and appropriate management might prevent the complications of this syndrome.

Hemodynamics and changes after STA-MCA anastomosis in moyamoya disease and atherosclerotic cerebrovascular disease measured by micro-Doppler ultrasonography

Moyamoya disease (MMD) and atherosclerotic cerebrovascular disease (ACVD) differ in angiographic appearance and probably hemodynamics. Pediatric MMD (PMMD) usually presents with cerebral ischemia, while intracranial hemorrhage is more common in adult MMD (AMMD), suggesting differences in cerebral hemodynamics. We analyzed the cortical flow velocity and direction of recipient arteries using micro-Doppler ultrasonography to evaluate the cortical circulation before and after anastomosis in MMD and ACVD. Twenty-eight patients with adult MMD (AMMD), 7 with pediatric MMD (PMMD), 16 with ACVD, and 12 control patients were studied. A micro-Doppler probe was applied on the cortical recipient artery (A4 or M4) before and after anastomosis. Systolic maximum flow velocity (V max) and blood flow direction were investigated at proximal and distal parts of anastomosed sites in recipient arteries. Pre- and postoperative regional cerebral blood flow was measured by cold xenon-computed tomography (Xe-CT). Before anastomosis, retrograde cortical flow was significantly more common in PMMD patients, and V max in cortical artery was significantly lower in AMMD patients. Bypass surgery changed the direction of blood flow from the anastomosis site to proximal and distal sites of the recipient artery in most patients, but pre-anastomosis flow direction was preserved more frequently in PMMD patients. The rate of V max increase after anastomosis was significantly higher in AMMD than in PMMD (11.6 ± 9.8 vs. 3.9 ± 1.8; P = 0.01). Micro-Doppler ultrasonography identified differences in cortical circulation among AMMD, PMMD, and ACVD. In AMMD, significantly low velocity in the cortical artery was observed before anastomosis, and bypass surgery reversed the flow and significantly increased flow velocity. The data of PMMD showed unique hemodynamics of the cortical artery before anastomosis, characterized by a higher frequency of retrograde flow and preserved velocity. The V max increase rate was significantly higher in patients with postoperative cerebral hyperperfusion on Xe-CT, and further study is warranted to validate the clinical use of intraoperative micro-Doppler monitoring to predict postoperative hyperperfusion.

The efficacy of superficial temporal artery–middle cerebral artery anastomosis in patients with moyamoya disease complaining of severe headache

Object

Some patients with moyamoya disease complain of severe headache, which may be closely related to cerebral ischemia. The efficacy of superficial temporal artery–middle cerebral artery (STA-MCA) anastomosis in these patients was evaluated by clinicoradiological studies.

Methods

Of 117 consecutive patients with ischemic moyamoya disease, 25 complained mainly of severe headache (headache group) and 92 had no significant headache (nonheadache group). Intensity of headache was evaluated pre- and postoperatively. Furthermore, regional cerebral blood flow (rCBF) and cerebrovascular reactivity (CVR) were assessed pre- and postoperatively.

Results

The headache group was significantly younger than the nonheadache group. In a group corrected for the age distribution, preoperative rCBF and CVR were similar in headache and nonheadache groups. After STA-MCA anastomosis, 16 patients with headache experienced complete relief from headache, 7 patients showed remarkable improvements and discontinued medications for headache, and the remaining 2 patients had some alleviation of headache but sometimes required medication. In the headache group, the postoperative rCBF was significantly greater than the preoperative value. The postoperative rCBF in this group was also significantly greater than the postoperative rCBF in the nonheadache group.

Conclusions

These data suggest that severe headache is one of the main symptoms in young patients with moyamoya disease probably related to cerebral circulatory disturbances. An STA-MCA anastomosis is effective in relieving headache in patients with ischemic moyamoya disease manifesting severe headache, probably by improving perfusion pressure and cerebral circulation.

Intracranial Hemorrhage Is Much More Common After Carotid Stenting Than After Endarterectomy

Background and Purpose—

Intracranial hemorrhage (ICH) is a rare and devastating complication of carotid revascularization. We sought to determine the prevalence of, type of, and risk factors associated with ICH among recipients of carotid endarterectomy (CEA) and carotid angioplasty and stenting (CAS) within the National Inpatient Sample (NIS).

Methods—

Postoperative cases of ICH after CEA (International Classification of Disease 9 th edition [ICD-9]: 38.12) or CAS (ICD-9: 00.63) were retrieved from the 2001 to 2008 NIS. Clinical presentation (asymptomatic versus symptomatic), discharge status, in-hospital mortality, demographics, and hospital characteristics were extracted from NIS data. Charlson indices of comorbidity were determined based on ICD-9 and clinical classification software codes. Multivariate regression was used to determine the impact of revascularization procedure type and symptom status on adverse outcomes, including ICH, in-hospital mortality, and unfavorable discharge status.

Results—

Among 57 663 486 NIS hospital admissions, 215 012 CEA and 13 884 CAS procedures were performed. Symptomatic presentations represented the minority of CEA (N=10 049; 5%) and CAS cases (N=1251; 10%). ICH occurred significantly more frequently after CAS than CEA in both symptomatic (4.4% versus 0.8%; P <0.0001) and asymptomatic presentations (0.5% versus 0.06%; P <0.0001). Multivariate regression suggested that symptomatic presentations (versus asymptomatic) and CAS procedures (versus CEA) were both independently predictive of 6-fold to 7-fold increases in the frequency of postoperative ICH. ICH was independently predictive in a 30-fold increased risk of mortality before discharge.

Conclusions—

CAS procedures are associated with elevated adverse outcomes, including ICH, in-hospital death, and unfavorable discharges, especially among symptomatic presentations.

Incidence and Predictive Factors of Cerebral Hyperperfusion After Extracranial-Intracranial Bypass for Occlusive Cerebrovascular Diseases

BACKGROUND:

Although many studies of postoperative cerebral hyperperfusion syndrome (CHS) after carotid endarterectomy have been reported, there are few reports related to extracranial-intracranial (EC-IC) bypass for atherosclerotic occlusive cerebrovascular diseases.

OBJECTIVE:

To examine the incidence of cerebral hyperperfusion and CHS after EC-IC bypass and to investigate predictive factors.

METHODS:

Fifty consecutive patients undergoing EC-IC bypass for atherosclerotic occlusive cerebrovascular diseases were studied. Immediately after bypass surgery, resting regional cerebral blood flow was determined under continuous sedation, and postoperative hyperperfusion was evaluated according to the definitions as follows: &gt; 50% increase in regional cerebral blood flow compared with the contralateral side (method 1) and &gt; 100% increase in corrected regional cerebral blood flow compared with preoperative values (method 2). Logistic regression analysis was conducted to determine the effect of multiple variables on postoperative hyperperfusion.

RESULTS:

Transient symptoms of CHS were observed in 3 patients. Cerebral hyperperfusion was detected in 12 patients (24%) as defined by method 1 and in 9 patients (18%) by method 2. Postoperative hyperperfusion occurred significantly more frequently in patients with the steal phenomenon (regional cerebral vasoreactivity ≤ 0%; P = .001 by method 1 and P = .001 by method 2) and correlated with impaired preoperative regional cerebral vasoreactivity (P &lt; .001). Logistic regression analysis revealed that the steal phenomenon was a significant risk factor for hyperperfusion as defined by both methods 1 (P = .009) and 2 (P = .03).

CONCLUSION:

The incidence of cerebral blood flow-assessed postoperative hyperperfusion after EC-IC bypass for atherosclerotic occlusive cerebrovascular diseases was not rare. Post EC-IC bypass CHS could be reduced by continuous, strict blood pressure control under sedation.