Bjørn Tennøe

Comparison of Cerebral Embolization During Off-Pump and On-Pump Coronary Artery Bypass Surgery

BACKGROUND Coronary artery bypass surgery with cardiopulmonary bypass carries a significant risk of perioperative brain injury. At least 1% to 5% will suffer a stroke, and at 3-months postoperatively approximately 30% are reported to have cognitive impairment assessed by neuropsychologic testing. In off-pump surgery cardiopulmonary bypass is not used and instrumentation on the ascending aorta is reduced. The main aim of this study was to assess if off-pump surgery reduces intraoperative cerebral embolization. METHODS This was a prospective and randomized study of two comparable groups with regard to age, sex, years of education, preoperative cognitive functioning, and surgical characteristics. Fifty-two patients (29 off-pump) were monitored by the use of transcranial Doppler ultrasound for cerebral microembolization during surgery. Preoperative and postoperative clinical, cerebral magnetic resonance imaging, and neuropsychologic examinations were also carried out. RESULTS There was a significant reduction in the number of cerebral microemboli during off-pump compared with on-pump surgery (16.3 [range 0 to 131] versus 90.0 [range 15 to 274], p < 0.0001). No significant difference with regard to the incidence of neuropsychologic performance (decline in 29% off-pump, 35% on-pump) or neuroradiologic findings at 3 months was found, and there was no association between the number of cerebral microemboli and cognitive outcome. CONCLUSIONS This study clearly demonstrates that off-pump surgery leads to a reduction in intraoperative cerebral microembolization. A significant reduction in the number of off-pump patients with cognitive decline or ischemic brain lesions on cerebral magnetic resonance imaging could not be demonstrated in this relatively small patient population.

Cerebral Microemboli and Brain Injury During Carotid Artery Endarterectomy and Stenting

Background and Purpose— Cerebral microembolic signals detected by transcranial Doppler are frequent during carotid angioplasty with stenting and carotid endarterectomy (CEA). Their potential harmful effects on the brain are, however, unclear. The aim of this study was to relate the frequency and type of per-procedural microembolic signals to procedure-related ipsilateral ischemic strokes and new ipsilateral ischemic lesions on diffusion-weighted cerebral MRI. Methods— Eighty-five patients who were prospectively treated with CEA (61) or carotid angioplasty with stenting (30) for high-grade (≥70%) internal carotid artery stenoses were monitored during the procedures using multifrequency transcranial Doppler with embolus detection and differentiation. Pre- and postprocedural cerebral diffusion-weighted cerebral MRIs were performed on a subset of patients. Results— Solid and gaseous microemboli were independently associated with procedure-related ipsilateral ischemic strokes (solid: P=0.027, gaseous: P=0.037) or new ipsilateral diffusion-weighted cerebral MRI lesions (solid: P=0.043, gaseous: P=0.026). Microembolic signals were detected during all procedures except one (CEA); 17% and 21% of all emboli were solid during carotid angioplasty with stenting and CEA, respectively. Patients undergoing carotid angioplasty with stenting had more solid (P<0.001) and gaseous (P<0.001) emboli and more new ipsilateral ischemic strokes (P=0.033) compared with patients undergoing CEA. Echolucent plaques (P=0.020) and preprocedural diffusion-weighted cerebral MRI ischemic lesions (P=0.002) were associated with increased numbers of solid emboli. Conclusions— Solid and gaseous microemboli were increased in patients with procedure-related ipsilateral ischemic strokes or new diffusion-weighted cerebral MRI lesions, which suggests that both solid and gaseous emboli may be harmful to the brain during CEA and carotid angioplasty with stenting.

A randomized double-blind controlled trial of intra-annular radiofrequency thermal disc therapy--a 12-month follow-up.

ABSTRACT The discTRODE™ probe applies radiofrequency (RF) current, heating the annulus to treat chronic discogenic low back pain. Randomized controlled studies have not been published. We assessed the long‐term effect and safety aspects of percutaneous intradiscal radiofrequency thermocoagulation (PIRFT) with the discTRODE™ probe in a prospective parallel, randomized and gender stratified, double‐blind placebo‐controlled study. Twenty selected patients with chronic low back pain and a positive one‐level pressure‐controlled provocation discography were randomized to either intra‐annular PIRFT or intra‐annular sham treatment. A blinded interim analysis was performed when 20 patients had been followed for six months. The 6‐month analysis did not reveal any trend towards overall effect or difference between active and sham treatment for the primary endpoint: change in pain intensity (0–10). The inclusion of patients was therefore discontinued. After 12 months the overall reduction from baseline pain had reached statistical significance, but there was no significant difference between the groups. The functional outcome measures (Oswestry Disability Index, and SF 36 subscales and the relative change in pain) appeared more promising, but did not reach statistical significance when compared with sham treatment. Two actively treated and two sham‐treated patients reported increased pain levels, and in both groups a higher number was unemployed after 12 months. The study did not find evidence for a benefit of PIRFT, although it cannot rule out a moderate effect. Considering the high number, reporting increased pain in our study, we would not recommend intra‐annular thermal therapy with the discTRODE™ probe.

Predictive modeling in glioma grading from MR perfusion images using support vector machines.

The advantages of predictive modeling in glioma grading from MR perfusion images have not yet been explored. The aim of the current study was to implement a predictive model based on support vector machines (SVM) for glioma grading using tumor blood volume histogram signatures derived from MR perfusion images and to assess the diagnostic accuracy of the model and the sensitivity to sample size. A total of 86 patients with histologically‐confirmed gliomas were imaged using dynamic susceptibility contrast (DSC) MRI at 1.5T. Histogram signatures from 53 of the 86 patients were analyzed independently by four neuroradiologists and used as a basis for the predictive SVM model. The resulting SVM model was tested on the remaining 33 patients and analyzed by a fifth neuroradiologist. At optimal SVM parameters, the true positive rate (TPR) and true negative rate (TNR) of the SVM model on the 33 patients was 0.76 and 0.82, respectively. The interobserver agreement and the TPR increased significantly when the SVM model was based on an increasing sample size (P < 0.001). This result suggests that a predictive SVM model can aid in the diagnosis of glioma grade from MR perfusion images and that the model improves with increasing sample size. Magn Reson Med 60:945–952, 2008.

Use of miglustat in a child with late-infantile-onset Niemann-Pick disease type C and frequent seizures: a case report

IntroductionNiemann-Pick disease type C is a rare genetic lysosomal storage disease associated with impaired intracellular lipid trafficking and a range of progressive neurological manifestations. The influence of seizure activity on disease course and response to miglustat therapy is not currently clear.Case presentationNiemann-Pick disease type C homozygous for NPC1 mutation p.S940L [c. 2819 C>T] was diagnosed in a four-and-a-half-year-old Norwegian Caucasian girl. The patient, who died at eight years and seven months of age, had a history of prolonged neonatal jaundice and subsequently displayed progressive neurological manifestations that started with delayed speech, ataxia, and gelastic cataplexy. A regimen of 100mg of miglustat three times a day was initiated when she was four years and 11 months old. She showed decreased neurological deterioration during about three and a half years of treatment. However, she displayed periods of distinct worsening that coincided with frequent epileptic seizures. Anti-epileptic therapy reduced seizure frequency and severity and allowed re-stabilization of her neurological function. Prior to her death, which was possibly due to acute cardiac arrest, seizure activity was well controlled.ConclusionsMiglustat delayed the expected deterioration of neurological function in this patient with p.S940L-homozygous late-infantile-onset Niemann-Pick disease type C and provided important quality-of-life benefits. This case demonstrates the importance of effective seizure control therapy in achieving and maintaining neurological stabilization in Niemann-Pick disease type C.

Comparison of cerebral embolization during off-pump and on-pump coronary artery bypass surgery: Invited commentary

Background. Coronary artery bypass surgery with cardiopulmonary bypass carries a significant risk of perioperative brain injury. At least 1% to 5% will suffer a stroke, and at 3-months postoperatively approximately 30% are reported to have cognitive impairment assessed by neuropsychologic testing. In off-pump surgery cardiopulmonary bypass is not used and instrumentation on the ascending aorta is reduced. The main aim of this study was to assess if off-pump surgery reduces intraoperative cerebral embolization. Methods. This was a prospective and randomized study of two comparable groups with regard to age, sex, years of education, preoperative cognitive functioning, and surgical characteristics. Fifty-two patients (29 off-pump) were monitored by the use of transcranial Doppler ultrasound for cerebral microembolization during surgery. Preoperative and postoperative clinical, cerebral magnetic resonance imaging, and neuropsychologic examinations were also carried out. Results. There was a significant reduction in the number of cerebral microemboli during off-pump compared with on-pump surgery (16.3 [range 0 to 131] versus 90.0 [range 15 to 274], p < 0.0001). No significant difference with regard to the incidence of neuropsychologic performance (decline in 29% off-pump, 35% on-pump) or neuroradiologic findings at 3 months was found, and there was no association between the number of cerebral microemboli and cognitive outcome. Conclusions. This study clearly demonstrates that off-pump surgery leads to a reduction in intraoperative cerebral microembolization. A significant reduction in the number of off-pump patients with cognitive decline or ischemic brain lesions on cerebral magnetic resonance imaging could not be demonstrated in this relatively small patient population.

Selective posterior cerebral artery amobarbital test: Its role in presurgical memory assessment in temporal lobe epilepsy

Summary:  Purpose: To evaluate the efficacy and risk of complications of selective posterior cerebral artery (PCA) amobarbital anesthesia in memory assessment of patients with epilepsy under consideration for temporal lobe resection.

Placebo control – Still the most ethical study design

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Cerebral Ischemic Injury and Cognitive Impairment After Off-Pump and On-Pump Coronary Artery Bypass Grafting Surgery

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