Jean-Baptiste Zerlauth

Cerebral Extracellular Lactate Increase is Predominantly Nonischemic in Patients with Severe Traumatic Brain Injury

Growing evidence suggests that endogenous lactate is an important substrate for neurons. This study aimed to examine cerebral lactate metabolism and its relationship with brain perfusion in patients with severe traumatic brain injury (TBI). A prospective cohort of 24 patients with severe TBI monitored with cerebral microdialysis (CMD) and brain tissue oxygen tension (PbtO2) was studied. Brain lactate metabolism was assessed by quantification of elevated CMD lactate samples (>4 mmol/L); these were matched to CMD pyruvate and PbtO2 values and dichotomized as glycolytic (CMD pyruvate > 119 μmol/L vs. low pyruvate) and hypoxic (PbtO2 < 20 mm Hg vs. nonhypoxic). Using perfusion computed tomography (CT), brain perfusion was categorized as oligemic, normal, or hyperemic, and was compared with CMD and PbtO2 data. Samples with elevated CMD lactate were frequently observed (41 ±8%), and we found that brain lactate elevations were predominantly associated with glycolysis and normal PbtO2 (73 ± 8%) rather than brain hypoxia (14 ±6%). Furthermore, glycolytic lactate was always associated with normal or hyperemic brain perfusion, whereas all episodes with hypoxic lactate were associated with diffuse oligemia. Our findings suggest predominant nonischemic cerebral extracellular lactate release after TBI and support the concept that lactate may be used as an energy substrate by the injured human brain.

Accuracy of Brain Multimodal Monitoring to Detect Cerebral Hypoperfusion After Traumatic Brain Injury

Objective:To examine the accuracy of brain multimodal monitoring—consisting of intracranial pressure, brain tissue PO2, and cerebral microdialysis—in detecting cerebral hypoperfusion in patients with severe traumatic brain injury. Design:Prospective single-center study. Patients:Patients with severe traumatic brain injury. Setting:Medico-surgical ICU, university hospital. Intervention:Intracranial pressure, brain tissue PO2, and cerebral microdialysis monitoring (right frontal lobe, apparently normal tissue) combined with cerebral blood flow measurements using perfusion CT. Measurements and Main Results:Cerebral blood flow was measured using perfusion CT in tissue area around intracranial monitoring (regional cerebral blood flow) and in bilateral supra-ventricular brain areas (global cerebral blood flow) and was matched to cerebral physiologic variables. The accuracy of intracranial monitoring to predict cerebral hypoperfusion (defined as an oligemic regional cerebral blood flow < 35 mL/100 g/min) was examined using area under the receiver-operating characteristic curves. Thirty perfusion CT scans (median, 27 hr [interquartile range, 20–45] after traumatic brain injury) were performed on 27 patients (age, 39 yr [24–54 yr]; Glasgow Coma Scale, 7 [6–8]; 24/27 [89%] with diffuse injury). Regional cerebral blood flow correlated significantly with global cerebral blood flow (Pearson r = 0.70, p < 0.01). Compared with normal regional cerebral blood flow (n = 16), low regional cerebral blood flow (n = 14) measurements had a higher proportion of samples with intracranial pressure more than 20 mm Hg (13% vs 30%), brain tissue PO2 less than 20 mm Hg (9% vs 20%), cerebral microdialysis glucose less than 1 mmol/L (22% vs 57%), and lactate/pyruvate ratio more than 40 (4% vs 14%; all p < 0.05). Compared with intracranial pressure monitoring alone (area under the receiver-operating characteristic curve, 0.74 [95% CI, 0.61–0.87]), monitoring intracranial pressure + brain tissue PO2 (area under the receiver-operating characteristic curve, 0.84 [0.74–0.93]) or intracranial pressure + brain tissue PO2+ cerebral microdialysis (area under the receiver-operating characteristic curve, 0.88 [0.79–0.96]) was significantly more accurate in predicting low regional cerebral blood flow (both p < 0.05). Conclusion:Brain multimodal monitoring—including intracranial pressure, brain tissue PO2, and cerebral microdialysis—is more accurate than intracranial pressure monitoring alone in detecting cerebral hypoperfusion at the bedside in patients with severe traumatic brain injury and predominantly diffuse injury.

Improvement of Neuroenergetics by Hypertonic Lactate Therapy in Patients with Traumatic Brain Injury Is Dependent on Baseline Cerebral Lactate/Pyruvate Ratio

Abstract Energy dysfunction is associated with worse prognosis after traumatic brain injury (TBI). Recent data suggest that hypertonic sodium lactate infusion (HL) improves energy metabolism after TBI. Here, we specifically examined whether the efficacy of HL (3h infusion, 30–40 μmol/kg/min) in improving brain energetics (using cerebral microdialysis [CMD] glucose as a main therapeutic end-point) was dependent on baseline cerebral metabolic state (assessed by CMD lactate/pyruvate ratio [LPR]) and cerebral blood flow (CBF, measured with perfusion computed tomography [PCT]). Using a prospective cohort of 24 severe TBI patients, we found CMD glucose increase during HL was significant only in the subgroup of patients with elevated CMD LPR >25 (n = 13; +0.13 [95% confidence interval (CI) 0.08–0.19] mmol/L, p < 0.001; vs. +0.04 [–0.05–0.13] in those with normal LPR, p = 0.33, mixed-effects model). In contrast, CMD glucose increase was independent from baseline CBF (coefficient +0.13 [0.04–0.21] mmol/L when global CBF was <32.5 mL/100 g/min vs. +0.09 [0.04–0.14] mmol/L at normal CBF, both p < 0.005) and systemic glucose. Our data suggest that improvement of brain energetics upon HL seems predominantly dependent on baseline cerebral metabolic state and support the concept that CMD LPR – rather than CBF – could be used as a diagnostic indication for systemic lactate supplementation following TBI.

Factors Associated With Focal Computed Tomographic Perfusion Abnormalities in Supratentorial Transient Ischemic Attacks

Background and Purpose— Computed tomographic perfusion (CTP) is useful in diagnosis of patients with transient focal neurological symptoms. In acute imaging of patients with a suspected transient ischemic attack (TIA), it remains unclear which patients develop focal perfusion abnormalities (FPA), that is, hypoperfusion or hyperperfusion. We aimed at determining independent factors associated with FPA in patients with supratentorial TIAs. Methods— We prospectively collected consecutive patients with supratentorial TIAs defined by the traditional time-based definition who underwent CTP within 24 hours of symptom onset. We recorded demographics, risk factors, clinical features, severity, and timing from onset. We documented the Age, Blood Pressure, Clinical Features, Duration, and Diabetes (ABCD2) scores, vascular territories, and presence of relevant arterial pathology. Variables were tested for an association with FPA with univariate and multivariate analyses. Results— A hundred and ten of 265 patients (42%) with supratentorial TIAs had FPA on CTP. Acute noncontrast computed tomography showed early ischemic lesions in 6%, and acute/subacute magnetic resonance imaging was pathological in 52 of the 109 cases (47.7%) where it was performed. Clinical factors associated with FPA were high-admission National Institutes of Health Stroke Scale (odds ratio [OR], 1.22), right hemispheric TIA (OR, 3.09), and cardioembolic mechanism (OR, 2.19). Persistence of symptoms during CTP (OR, 2.59), shorter duration of TIA (OR, 0.93), major intracranial arterial pathology (OR, 12.5), and extracranial arterial occlusion (OR, 7.44) were also associated with FPA. Conclusions— Supratentorial TIAs are often associated with FPA in CTP, even after symptom resolution. FPAs are frequent in severe TIAs and those associated with cardioembolism or specific arterial pathologies. These findings can help clinicians in accurate diagnosis of TIA and its underlying mechanisms.

Bedside cerebral microdialysis monitoring of delayed cerebral hypoperfusion in comatose patients with poor grade aneurysmal subarachnoid haemorrhage.

Background Delayed cerebral ischaemia (DCI) is frequent after poor grade aneurysmal subarachnoid haemorrhage (SAH). Owing to the limited accuracy of clinical examination, DCI diagnosis is often based on multimodal monitoring. We examined the value of cerebral microdialysis (CMD) in this setting. Methods 20 comatose SAH participants underwent CMD monitoring—for hourly sampling of cerebral extracellular lactate/pyruvate ratio (LPR) and glucose—and brain perfusion CT (PCT). Patients were categorised as DCI when PCT (8±3 days after SAH) showed cerebral hypoperfusion, defined as cerebral blood flow <32.5 mL/100 g/min with a mean transit time >5.7 s. Clinicians were blinded to CMD data; for the purpose of the study, only patients who developed cerebral hypoperfusion in anterior and/or middle cerebral arteries were analysed. Results DCI (n=9/20 patients) was associated with higher CMD LPR (51±36 vs 31±10 in patients without DCI, p=0.0007) and lower CMD glucose (0.64±0.34 vs 1.22±1.05, p=0.0005). In patients with DCI, CMD changes over the 18 hours preceding PCT diagnosis revealed a pattern of CMD LPR increase (coefficient +2.96 (95% CI 0.13 to 5.79), p=0.04) with simultaneous CMD glucose decrease (coefficient −0.06 (95% CI −0.08 to −0.01), p=0.03, mixed-effects multilevel regression model). No significant CMD changes were noted in patients without DCI. Conclusions In comatose patients with SAH, delayed cerebral hypoperfusion correlates with a CMD pattern of lactate increase and simultaneous glucose decrease. CMD abnormalities became apparent in the hours preceding PCT, thereby suggesting that CMD monitoring may anticipate targeted therapeutic interventions.

Letter to the Editor. Clipping after Pipeline embolization device placement for a thrombosed ACoA aneurysm

TO THE EDITOR: We read with great interest the article published by Daou and colleagues2 (Daou B, Chalouhi N, Starke RM, et al: Clipping of previously coiled cerebral aneurysms: efficacy, safety, and predictors in a cohort of 111 patients. J Neurosurg 125:1337–1343, December 2016). This publication has enormous interest for cerebrovascular neurosurgeons working in centers that offer both endovascular and surgical aneurysm repair strategies. Surgical treatment of aneurysms previously treated with endovascular therapy presents several constraints, as mentioned in this article. We would like to provide from our practice an additional example of clipping an aneurysm that had been previously treated with a stent as we think it would be interesting to readers of the cited article. While ruling out causes of chronic headache, we diagnosed a 70-year-old woman with an aneurysm of the anterior communicating artery (ACoA), with its neck at the left A1–A2 junction. The aneurysm measured 8 × 8.5 mm. The dome of the aneurysm was pointing anteroinferiorly and had an intraluminal thrombus (Fig. 1). She had no visual or other neurological deficits associated with the aneurysm. Considering the size and location of the aneurysm, our multidisciplinary team proposed treatment. Both surgical and endovascular options were suggested, and the patient elected to undergo the endovascular option. A 2.75 × 16–mm Pipeline embolization device (PED) was positioned on the left A1–A2 segments under biplane fluoroscopic guidance. The immediate postprocedural digital subtraction angiography (DSA) study showed marked contrast stasis within the sac, compatible with reduced inflow. Treatment with aspirin and clopidogrel had been instituted 1 week before the procedure, without any antiplatelet resistance on biological tests. Magnetic resonance angiography (MRA) performed 1 month after treatment showed no evidence of blood flow inside the aneurysm sac, and the patient had a normal neurological examination. Three months after intervention, the patient experienced progressive diminution of vision in the left eye, and in the space of a week she had no light perception in this eye. Visual field and optical coherence tomography (OCT) findings suggested a lesion of the retrobulbar, prechiasmatic optic nerve on the left side (Fig. 2A and C). Magnetic resonance imaging, MRA, and DSA showed complete exclusion of the treated aneurysm and normal flow within the parent vessel but also a paradoxical increase in size related to intrasacular thrombosis, leading to worsening of the mass effect and optic neuropathy (Fig. 3). After discussion in the multidisciplinary neurovascular board, we elected to treat this aneurysm surgically. The optic nerve was markedly compressed by a turgid thrombosed aneurysm with solid and liquid components. The thrombosed aneurysm sac was excised after decompression of the sac contents, and the aneurysm neck was clipped. The aneuysm sac was completely dissected away from the optic nerve, thus achieving good decompression of the nerve (Fig. 4). The patient recovered her vision completely in the first 2 postoperative days, which was later confirmed with formal assesments of visual acuity, fields, and OCT (Fig. 2B and D). As Colby and colleagues recently showed in a nonrandomized retrospective series,1 flow diversion using a PED for the repair of an ACoA aneurysm seems to have an extremely high rate of success (96%) immediately after the procedure. With respect to long-term results, this study showed complete occlusion of the aneurysm in 86% at an average follow-up of 10.4 months. The safety and efficacy of PED placement in terms of ophthalmological outcome after coiling large and giant internal carotid artery aneurysms were evaluated by Sahlein et al.4 while analyzing the results of the Pipeline for Uncoilable or Failed Aneurysms (PUFS) trial. These authors found that the procedure was related to a 5% worsening of previous ophthalmological deficit, attributed to ischemia of the ophthalmic artery territory. Gressot et al.3 have recently shown that

Renal cell carcinoma metastasis involving vertebral hemangioma: dual percutaneous treatment by navigational bipolar radiofrequency ablation and high viscosity cement vertebroplasty

The case of a 70-year-old woman with progressive renal cell carcinoma (RCC) metastatic invasion of a L3 vertebral hemangioma treated by dual percutaneous radiofrequency ablation (RFA) and vertebroplasty is reported. The patient was surgically treated for RCC in 2001. Chemotherapy and immunotherapy were introduced in 2013 for ovarian, bladder and cerebral metastatic disease. An asymptomatic L3 benign hemangioma was noticed at this time. One-year CT and MRI follow-up studies demonstrated a nodular isolated soft tissue lesion involving the anterior edge of the hemangioma. Percutaneous treatment consisted of a L3 vertebral body unipedicular approach to perform a biopsy, RFA with a navigational bipolar RFA device and vertebroplasty using high viscosity cement. Histopathological examination confirmed metastasis of RCC. The 5-month spinal MRI and CT examinations demonstrated complete disappearance of the tumor.

Tearing of the left iliac vessels in lumbar surgery revealed by multiphase post-mortem CT-angiography (MPMCTA)

Lumbar surgery is regularly applied in cases of discal hernia and acquired lumbar stenosis. In this report, we present a case of a laceration in the left common iliac artery and iliac vein during a lumbar surgery and discuss the literature concerning this kind of event. In the present case, the surgical procedure was followed by a sudden decrease in blood pressure, and the surgeon discovered an intra-abdominal haemorrhage that led to the patients death. Postmortem investigation confirmed the intra-abdominal haemorrhage and revealed a laceration of the proximal portion of the left common iliac artery and left iliac vein. The source of bleeding could be detected especially thanks to multi-phase postmortem CT angiography (MPMCTA), which was performed prior to autopsy. We also found a haemorrhagic path through the intervertebral disc between the L4-L5 vertebrae, caused by the surgeons instrument (pituitary rongeur). To date, a few cases have been described of iatrogenic death resulting from a tear in the iliac vessels during lumbar surgery, but not from the postmortem perspective. Such investigations have recently been modernized thanks to the introduction of forensic imaging. In particular, MPMCTA offers new possibilities in postmortem investigations and can be considered the new gold standard for investigating deaths related to medical intervention. Here we describe the first case of a death during lumbar surgery using this new method.

Impact of model-based iterative reconstruction (MBIR) on image quality in cerebral CT angiography before and after intracranial aneurysm treatment

PURPOSE To subjectively and objectively assess the impact of model-based iterative reconstruction(MBIR) on image quality in cerebral computed tomography angiography compared to adaptive statistical iterative reconstruction (ASIR). METHODS 107 patients (mean age: 58 ± 14 years) were included prior to (n = 38) and after (n = 69) intracranial aneurysm treatment. Images were acquired using a routine protocol and reconstructed with MBIR and ASIR. Image noise, signal-to-noise (SNR) and contrast-to-noise (CNR) ratios in the internal carotid and middle cerebral arteries were compared between MBIR and ASIR using the Wilcoxon signed-rank test. Additionally, two neuroradiologists subjectively assessed noise, artefacts, vessel sharpness and overall quality using a semi-quantitative assessment scale. RESULTS Objective assessment revealed that MBIR reduced noise (p < 0.0001) and additionally improved SNR (p < 0.0001) and CNR (p < 0.0001) compared to ASIR in untreated and treated patients. Subjective assessment revealed that in untreated patients, MBIR improved noise reduction, artefacts, vessel sharpness and overall quality relative to ASIR (p < 0.0001). In the treated groups, noise and vessel sharpness were improved (p < 0.0001) with no change in artefacts on images reconstructed with MBIR compared to ASIR. CONCLUSION MBIR significantly improves noise, SNR, CNR and vessel sharpness in untreated and treated patients with intracranial aneurysms. MBIR does not reduce artefacts generated by metallic devices following intracranial aneurysm treatment.

Balloon-assisted coil embolization and large stent delivery for cerebral aneurysms with a new generation of dual lumen balloons (Copernic 2L)

Introduction Dual coaxial lumen balloon microcatheters through which small stents can be delivered have recently been described. We report a series of a new type of dual lumen balloon catheter with a parallel lumen design enabling enhanced inflation and deflation properties through which larger stents may be deployed, including flow diverters (FD). Methods All aneurysms that were treated with a Copernic 2L (COP2L) dual lumen balloon catheter at our institution between February 2014 and December 2016 were assessed. Patient demographics, aneurysm characteristics, clinical and angiographic follow-up, as well as adverse events were analyzed. Results A total of 18 aneurysms in 16 patients (14 women) were treated with the COP2L. Mean maximal aneurysm diameter was 6.4 mm, mean neck size was 3.3 mm (min 1; max 6.3), and mean aneurysm height/width was 1.1 (min 0.5; max 2.1). The COP2L was used for balloon-remodeled coiling exclusively in 2 aneurysms; coiling and FD stenting in 8; coiling and braided stent delivery in 3; coiling, braided and FD stenting in 1; and FD stenting without coiling in 4 (stenting alone). The rate of Roy–Raymond 1 (complete occlusion) changed from 22% in the immediate postoperative period to 100% at 3 months (mean imaging follow-up 8.2 months). There were three technical complications (3/16, 18.7%), including a perforation and two thromboembolic asymptomatic events that were rapidly controlled with the COP2L. There was no immediate or delayed morbidity or mortality (modified Rankin Scale score 0–1 in 100% of patients). Conclusion The COP2L is a new type of dual lumen balloon catheter that may be useful for balloon and/or stent-assisted coiling of cerebral aneurysms. The same device can be used to deliver stents up to 4.5 mm and to optimize stent/wall apposition or serve as a life-saving tool in case of thromboembolic or hemorrhagic events. Long-term efficacy and safety need to be further assessed with larger case-controlled cohorts.