Intracranial Balloon Research Articles

Preliminary Observations of the Loke Microdialysis in an Experimental Pig Model: Are We Ready for Continuous Monitoring of Brain Energy Metabolism?

Brain energy metabolism is often disturbed after acute brain injuries. Current neuromonitoring methods with cerebral microdialysis (CMD) are based on intermittent measurements (1-4 times/h), but such a low frequency could miss transient but important events. The solution may be the recently developed Loke microdialysis (MD), which provides high-frequency data of glucose and lactate. Before clinical implementation, the reliability and stability of Loke remain to be determined in vivo. The purpose of this study was to validate Loke MD in relation to the standard intermittent CMD method. Four pigs aged 2-3 months were included. They received two adjacent CMD catheters, one for standard intermittent assessments and one for continuous (Loke MD) assessments of glucose and lactate. The standard CMD was measured every 15 min. Continuous Loke MD was sampled every 2-3 s and was averaged over corresponding 15-min intervals for the statistical comparisons with standard CMD. Intravenous glucose injections and intracranial hypertension by inflation of an intracranial epidural balloon were performed to induce variations in intracranial pressure, cerebral perfusion pressure, and systemic and cerebral glucose and lactate levels. In a linear mixed-effect model of standard CMD glucose(mM), there was a fixed effect value (± standard error [SE]) at 0.94 ± 0.07 (p < 0.001) for Loke MD glucose(mM), with an intercept at - 0.19 ± 0.15 (p = 0.20). The model showed a conditional R2 at 0.81 and a marginal R2 at 0.72. In a linear mixed-effect model of standard CMD lactate(mM), there was a fixed effect value (± SE) at 0.41 ± 0.16 (p = 0.01) for Loke MD lactate(mM), with an intercept at 0.33 ± 0.21 (p = 0.25). The model showed a conditional R2 at 0.47 and marginal R2 at 0.17. The established standard CMD glucose thresholds may be used as for Loke MD with some caution, but this should be avoided for lactate.

DRug-coated Balloon for Endovascular treatment of sYmptOmatic intracraNial stenotic Disease (DR. BEYOND): the protocol of a multicentre randomised trial

BackgroundAlthough endovascular stenting is considered an effective and safe therapeutic option for symptomatic intracranial atherosclerotic disease (sICAD), an elevated rate of restenosis remains an important issue for the conventional bare-metal...

Strain-induced collagen denaturation is rate dependent in failure of cerebral arteries.

While soft tissues are commonly damaged by mechanical loading, the manifestation of this damage at the microstructural level is not fully understood. Specifically, while rate-induced stiffening has been previously observed in cerebral arteries, associated changes in microstructural damage patterns following high-rate loading are largely undefined. In this study, we stretched porcine middle cerebral arteries to failure at 0.01 and >150 s-1, both axially and circumferentially, followed by probing for denatured tropocollagen using collagen hybridizing peptide (CHP). We found that collagen fibrils aligned with the loading direction experienced less denaturation following failure tests at high than low rates. Others have demonstrated similar rate dependence in tropocollagen denaturation during soft tissue failure, but this is the first study to quantify this behavior using CHP and to report it for cerebral arteries. These findings may have significant implications for traumatic brain injury and intracranial balloon angioplasty. We additionally observed possible tropocollagen denaturation in vessel layers primarily composed of fibrils transversely aligned to the loading axis. To our knowledge, this is the first observation of collagen denaturation due to transverse loading, but further research is needed to confirm this finding. STATEMENT OF SIGNIFICANCE: Previous work shows that collagen hybridizing peptide (CHP) can be used to identify collagen molecule unfolding and denaturation in mechanically overloaded soft tissues, including the cerebral arteries. But experiments have not explored collagen damage at rates relevant to traumatic brain injury. In this work, we quantified collagen damage in cerebral arteries stretched to failure at both high and low rates. We found that the collagen molecule is less damaged at high than at low rates, suggesting that damage mechanisms of either the collagen molecule or other elements of the collagen superstructure are rate dependent. This work implies that arteries failed at high rates, such as in traumatic brain injury, will have different molecular-level damage patterns than arteries failed at low rates. Consequently, improved understanding of damage characteristics may be expanded in the future to better inform clinically relevant cases of collagen damage such as angioplasty and injury healing.

Rescue Intracranial Balloon Angioplasty with or without Stent Placement in Acute Strokes with Intracranial Atherosclerotic Disease

Optimal management of acute ischemic stroke (AIS) secondary to intracranial atherosclerotic disease (ICAD) refractory to conventional mechanical thrombectomy remains unclear. We aimed to investigate the clinical outcome of patients undergoing rescue intracranial balloon angioplasty with or without stent placement in the setting of AIS in our institution. This is a retrospective single-arm observational study to evaluate the efficacy and safety of rescue balloon angioplasty with or without stent placement in emergent large vessel occlusion (EVLO) strokes with underlying ICAD. We included all patients undergoing such rescue intervention within 24hours of AIS presentation with EVLO between 2017 and 2021. We further evaluated stent or vessel reocclusion. Of 20 patients undergoing rescue intervention, 3 cases achieved adequate recanalization of artery using balloon angioplasty alone. Seventeen patients required stent placement. Fourteen (70%) procedures resulted in National Institutes of Health Stroke Scale improvement in postprocedure and upon discharge. Among 6 (30%) procedures with worsening neurological measures, 3 had reoccluded stent 24-48hours after procedure, 2 had symptomatic hemorrhagic conversion, and 1 had perforator occlusion. Nine patients (45%) had favorable functional outcome (modified Rankin Scale ≤2) at discharge, unchanged or improved at 3-month follow-up. The median modified Rankin Scale score was 4 (Interquartile range: 1.75-4) at discharge, improving to 3 (Interquartile range: 0-4) at 3-month follow-up. Two patients (10%) died during hospital stay. Rescue angioplasty with or without stenting can lead to significant clinical improvement in patients with ICAD presenting with ELVO and refractory to thrombectomy; however, this procedure is associated with a high rate of morbidity in acute setting.

Animal models for the study of intracranial hematomas (Review).

Intracranial hematomas (ICH) are a frequent condition in neurosurgical and neurological practices, with several mechanisms of primary and secondary injury. Experimental research has been fundamental for the understanding of the pathophysiology implicated with ICH and the development of therapeutic interventions. To date, a variety of different animal approaches have been described that consider, for example, the ICH evolutive phase, molecular implications and hemodynamic changes. Therefore, choosing a test protocol should consider the scope of each particular study. The present review summarized investigational protocols in experimental research on the subject of ICH. With this subject, injection of autologous blood or bacterial collagenase, inflation of intracranial balloon and avulsion of cerebral vessels were the models identified. Rodents (mice) and swine were the most frequent species used. These different models allowed improvements on the understanding of intracranial hypertension establishment, neuroinflammation, immunology, brain hemodynamics and served to the development of therapeutic strategies.

Intracranial Pulsating Balloon-Based Cardiac-Gated ICP Modulation Impact on Brain Oxygenation: A Proof-of-Concept Study in a Swine Model.

Brain oxygenation improvement is a sought-after goal in neurocritical care patients. Previously, we have shown that cerebral blood flow improvement by cardiac-gated intracranial pressure (ICP) modulation using an intracranial pulsating balloon is feasible in a swine model. We sought to explore specific ICP modulation protocols to assess the feasibility of influencing brain oxygenation. A previously presentedelectrocardiogram (ECG)-gated intracranial balloon pump in which volume, timing, and duty cycle of balloon inflation could be altered was used. Different protocols were tested in a swine model of normal and elevated ICP attained by intracranial fluid infusion with continuous monitoring of physiological parameters, andbrain tissue oxygen tension (PbtO2)was measured at baseline and after device activation. We studied five swine, subjected to two main protocols differing in their phase relative to the cardiac cycle. In reduced brain perfusion status (ICP > 20mm Hg, PbtO2 < 15mm Hg), the late-diastolic-early-systolic (Inflation/deflation) protocol showed consistent elevation in PbtO2 (+ 9%, p < 0.01), coupled with ICP reduction (- 12%, p < 0.01), whereas the early-systolic-late-diastolic (inflation/deflation) protocol resulted in PbtO2 reduction (- 4%, p < 0.01), coupled with ICP increase (+ 5% above baseline, p < 0.01). No significant changes in brain oxygenation or ICP were observed at normal perfusion status (ICP < 20mm Hg, PbtO2 > 15mm Hg). Intracranial cardiac-gated balloon pump activation can influence cerebral oxygenation and raise PbtO2 above threshold values. This study supports the concept of late-diastolic pressure rise, coupled with early-systolic pressure drop, as a potential effector of flow augmentation leading to improve brain tissue oxygenation. Further studies are warranted to assess the translational potential of using an intracranial cardiac-gated balloon pump device to improve brain tissue oxygenation.

Characterizing Brain Perfusion in a Swine Model of Raised Intracranial Pressure

IntroductionPerfusion of the brain is critical, but this can be compromised due to focal space occupying lesions (SOL). SOLs can raise intracranial pressure (ICP), resulting in reduced cerebral blood flow (CBF). Most gyrencephalic models of brain injury focus on parenchymal injury, with few models of acutely elevated ICP. We hypothesized that we could employ a SOL technique to develop a titratable ICP model and sought to quantitate the resulting decrease in brain perfusion. MethodsSix swine were anesthetized and instrumented. A Fogarty balloon catheter was inserted intracranially. Blood CO2 partial pressure was maintained between 35 and 45 mmHg. The Fogarty balloon was infused with normal saline at 1 mL/min to ICP targets of 10, 20, 30, and 40 mmHg. CBF (mL/100 g/min) were assessed at each ICP level using computed tomography perfusion (CTP). Data are presented as the mean ± standard deviation with all pressures measured in mmHg. CBF values were compared between baseline and each ICP level using analysis of variance. ResultsBaseline ICP was 5 ± 2 and systolic blood pressure was 106 ± 7. Balloon volumes (mL) required to achieve each incremental ICP level were 2.4 ± 0.5, 4.9 ± 1.7, 7.6 ± 1.6, and 9.9 ± 1.7. CBF decreased with each raised ICP level, with CBF being significantly less than baseline at ICP values of 30 (56.1 ± 34.7 versus 20.6 ± 11.0, P < 0.05) and 40 (56.1 ± 34.7 versus 6.5 ± 10.6, P < 0.05). ConclusionsAn intracranial balloon catheter can be used to increase ICP, delivering a proportionate reduction in CBF. This model can be used in the future studies to examine adjuncts that manipulate intracranial pressure and their effect on brain perfusion.

Abstract TP156: Balloon Angioplasty For Symptomatic Intracranial Artery Stenosis

Background: Intracranial atherosclerotic disease is the most common cause of ischemical cerebrovascular events. The risk of stroke recurrence or death of ICAD patients remains very high. Previous nonrandomized studies have showed that stroke and death rate of angioplasty for ICAD patients with severe stenosis of intracranial artery is lower than that of aggressive medication. Methods: The trial is a multicenter, prospective, randomized, parallel controlled study, with the primary idea to determine whether intracranial balloon angioplasty combined with aggressive medical therapy is superior to aggressive medical treatment alone in patients with cerebral ischemic stroke due to neurovascular stenosis (≥70%) for preventing the primary endpoint: 1.Stroke (including hemorrhagic and ischemic stroke) and all-cause mortality within 30 days after enrollment. 2. Ischemic stroke attributed to the offending vessel from 31 days to 12 months after enrollment. Aggressive medical treatment is identical in both arms, which consists of aspirin 100 mg per day during the entire follow-up and clopidogrel 75mg per day for the first 90 days after enrollment. Management of primary risk factors (blood pressure 130-140 / 90-100 mmHg and LDL &lt; 70 mg/dl) and secondary risk factors is also required in both arms. Result: We postulate that balloon angioplasty with submaximal balloon is safe enough and effective enough, not increasing ischemic/hemorrhagic stroke rate within 30 days. Moreover, we expect primary angioplasty combined with optimal medical management can reduce a relatively 50% risk of recurrent ischemic stroke due to attributed artery with estimated rate of 15% at 1 year in the control group and 7% in the treatment group in 1-year follow-up. Conclusion: BASIS is the first randomized trial comparing primary angioplasty combined with optimal medical regime with optimal medical regime alone. With enough evidence, we believe the risk of major hemorrhage can also be maximal minimized by using submaximal balloon during the procedure and probably shorter-term dual antiplatelet treatment after procedure. With the result of BASIS, we hope primary angioplasty can serve as an independent or alternative treatment in patients with severe intracranial atherosclerotic stenosis

Effect of increased positive end-expiratory pressure on intracranial pressure and cerebral oxygenation: impact of respiratory mechanics and hypovolemia

BackgroundTo evaluate the impact of positive end-expiratory pressure (PEEP) on intracranial pressure (ICP) in animals with different respiratory mechanics, baseline ICP and volume status.MethodsA total of 50 male adult Bama miniature pigs were involved in four different protocols (n = 20, 12, 12, and 6, respectively). Under the monitoring of ICP, brain tissue oxygen tension and hemodynamical parameters, PEEP was applied in increments of 5 cm H2O from 5 to 25 cm H2O. Measurements were taken in pigs with normal ICP and normovolemia (Series I), or with intracranial hypertension (via inflating intracranial balloon catheter) and normovolemia (Series II), or with intracranial hypertension and hypovolemia (via exsanguination) (Series III). Pigs randomized to the control group received only hydrochloride instillation while the intervention group received additional chest wall strapping. Common carotid arterial blood flow before and after exsanguination at each PEEP level was measured in pigs with intracranial hypertension and chest wall strapping (Series IV).ResultsICP was elevated by increased PEEP in both normal ICP and intracranial hypertension conditions in animals with normal blood volume, while resulted in decreased ICP with PEEP increments in animals with hypovolemia. Increasing PEEP resulted in a decrease in brain tissue oxygen tension in both normovolemic and hypovolemic conditions. The impacts of PEEP on hemodynamical parameters, ICP and brain tissue oxygen tension became more evident with increased chest wall elastance. Compare to normovolemic condition, common carotid arterial blood flow was further lowered when PEEP was raised in the condition of hypovolemia.ConclusionsThe impacts of PEEP on ICP and cerebral oxygenation are determined by both volume status and respiratory mechanics. Potential conditions that may increase chest wall elastance should also be ruled out to avoid the deleterious effects of PEEP.

Technique for Treatment of a Symptomatic Intracranial Stenosis With Balloon Angioplasty and Wingspan Stent Placement: 3-Dimensional Operative Video.

Intracranial angioplasty and stenting is an increasingly common modality to treat intracranial atherosclerosis, which accounts for 80 000 strokes annually. Early trials showed there to be a high complication rate1,2 associated with stenting but with improved technique this complication rate has dramatically decreased.3 The following video details the procedure of intracranial balloon angioplasty and stenting for a high-grade stenosis of the right internal carotid artery. The risks and benefits of the procedure were discussed with the patient and they consented to the procedure.

Augmented reality enhanced tele-proctoring platform to intraoperatively support a neuro-endovascular surgery fellow.

Remote tele-proctoring has been conducted in neuro-endovascular surgery, however, evidence to support its use in the fellowship training is limited. We demonstrate a novel augmented reality tele-proctoring platform to enable a remote attending to guide a fellow. A consecutive series of neuro-endovascular cases were performed by a neuro-endovascular fellow with remote guidance from an attending surgeon. The fellow and attending were connected using a commercially available cloud-based platform designed to capture and stream up to four live video feeds from a clinical environment to a remote user. In this setting, two video streams were obtained directly from the anteroposterior and lateral cameras on the biplane. Additional video of the operator from a telescopic camera was streamed live to the remote attending surgeon. The attending could provide immediate vocal feedback and also deploy the platform's augmented reality tools to communicate with the fellow in the angiography suite. A total of 10 cases were performed on eight patients utilizing the cloud-based tele-proctoring platform to facilitate instruction. The series included diagnostic angiograms and interventions such as intracranial balloon angioplasty, carotid stenting, and intracranial stenting. All cases were a technical success. No complications or deaths occurred. When compared to similar cohort of 10 cases prior to these which utilized a traditional instruction paradigm; we saw no differences in contrast use (p = 0.38), fluoroscopy time (p = 0.85), or technical success. This study demonstrates successful use of an augmented reality tele-proctoring platform to guide a neuro-endovascular fellow through complex neuro-interventional procedures from a remote setting.

Experimental Lung Donor Models for Transplant

<h3>Purpose</h3> The main types of accepted donations may be divided into: Donation after Brain Death and Donation after Circulatory Death. In addition to that, some important events are frequently associated to these two types of donors, such as Hemorrhagic Shock (HS) and Cold Ischemia (CI). These events also guide the standardization of the various experimental models developed by research groups for the employment of specific treatments: brain death (BD), circulatory death (CD), HS and CI. In this study, we aimed to describe and compare the lung mechanics and inflammatory process related to these four experimental models of lung donors. <h3>Methods</h3> Forty Sprague-Dawley rats were divided into 4 groups: BD (intracranial Fogarty balloon inflation), HS (hypovolemic protocol - 40 mmHg), CD (circulatory death + 3 h warm ischemia) and CI (6 h cold ischemia). Inflammatory responses and edema were assessed. In addition to these, as the BD and HS rats were kept hemodynamically stable for six hours, monitoring of lung mechanics was possible. <h3>Results</h3> Six hours after the induction of the HS, increase in elastance and resistance were observed (fig. 1). In lung tissue, BD and HS presented high levels of IL-1β and IL-6 in comparison to the CD and CI groups. In contrast, IL-10 levels were higher in the HS group, being significantly different when compared to the CD group. Finally, the BD group had the highest lung wet-to-dry ratio (fig. 2). <h3>Conclusion</h3> The experimental model of HS cause dysfunction of the lung mechanics. BD and HS lead to increased levels of cytokines and lung edema. These differences should be carefully considered to choose the ideal experimental model for developing specific therapeutic strategies.

Estimation of intracranial pressure by ultrasound of the optic nerve sheath in an animal model of intracranial hypertension

BackgroundUltrasound of the optic nerve sheath diameter (ONSD) has been used as a non-invasive and cost-effective bedside alternative to invasive intracranial pressure (ICP) monitoring. However, ONSD time-lapse behavior in intracranial hypertension (ICH) and its relief by means of either saline infusion or surgery are still unknown. The objective of this study was to correlate intracranial pressure (ICP) and ultrasonography of the optic nerve sheath (ONS) in an experimental animal model of ICH and determine the interval needed for ONSD to return to baseline levels. MethodsAn experimental study was conducted on 30 pigs. ONSD was evaluated by ultrasound at different ICPs generated by intracranial balloon inflation, saline infusion, and balloon deflation, and measured using an intraventricular catheter. ResultsAll variables obtained by ONS ultrasonography such as left, right, and average ONSD (AON) were statistically significant to estimate the ICP value. ONSD changed immediately after balloon inflation and returned to baseline after an average delay of 30 min after balloon deflation (p = 0.016). No statistical significance was observed in the ICP and ONSD values with hypertonic saline infusion. In this swine model, ICP and ONSD showed linear correlation and ICP could be estimated using the formula: −80.5 + 238.2 × AON. ConclusionIn the present study, ultrasound to measure ONSD showed a linear correlation with ICP, although a short delay in returning to baseline levels was observed in the case of sudden ICH relief.

Cerebral hypoperfusion necessitating additional bypass following hunterian ligation of the internal carotid artery despite reassuring intraoperative challenges: Video case report

Background: Hunterian ligation has been adapted for complex intracranial aneurysm repair when other, more modern techniques are insufficient. Before drastic alteration of cerebral blood flow dynamics, intraoperative challenges and consideration of blood flow dynamics must be completed to ensure adequate perfusion postligation. On satisfaction, ligation may proceed; however, subtle changes related to hypoperfusion may not be immediately observed during intraoperative challenge under general anesthesia and/or before onset of the vasospasm window.Case Description: In this report, we describe a patient who presented with a Hunt-Hess Grade III subarachnoid hemorrhage (SAH), with a right internal carotid artery (ICA) occlusion and a ruptured giant left ICA aneurysm. Endovascular treatment of the aneurysm was aborted because the nominal, 9 mm diameter of the ICA was too large for any intracranial balloon or stent. Three days later, she underwent a left-sided “insurance” extracranial-tointracranial arterial bypass (EIAB) using the superficial temporal artery simultaneously with hunterian ligation of the left ICA following reassuring results on intraoperative occlusion challenge. Over several days, her neurologic condition declined concurrent with the vasospasm window, and a right-sided EIAB was required to augment vascular supply. Following a protracted hospital course, the patient became progressively more independent and is currently residing in an assisted living facility.Conclusion: We illustrate an ultimately successful microsurgical treatment option in the setting of acute SAH that highlights the importance of cerebrovascular reserve and blood flow replacement in the setting of a compromised circle of Willis, especially during the vasospasm window.

Risk of mechanical thrombectomy recanalization failure: Intraoperative nuances and the role of intracranial atherosclerotic disease

ObjectiveTo present intraoperative observations that when recognized may facilitate the identification of patients at high risk of MT recanalization failure. We illustrate 4 cases of successful recanalization via rescue treatment with balloon angioplasty and/or stenting when such observations were noted. We also discuss the role of intracranial atherosclerotic disease in recanalization failure. Patients and methodsWe conducted a retrospective review of a prospectively maintained database for 450 stroke patients and identified 122 patients who underwent MT that failed to achieve recanalization. Operative notes were reviewed, and intraoperative nuances were discussed amongst neurointerventionalists. ResultsIntraoperative observations that may suggest a high risk of MT recanalization failure include resistance to microwire advancement, significant resistance to microcatheter advancement, temporary antegrade flow upon stent retriever (SR) deployment, temporary retrograde flow upon SR deployment with simultaneous aspiration, restricted SR expansion (“pinched device”), moderate resistance to total impedance of SR removal causing vessel/SR stretch on angiographic roadmap, and minimal recanalization after ≥3 device passes. ConclusionIntraoperative observations may facilitate early recognition of patients at high risk of MT recanalization failure. We suggest considering rescue treatment when such observations are noted to avoid prolonged procedure times, futile reperfusion, and reocclusion post-MT. Intracranial balloon angioplasty and/or stenting may be a safe and effective treatment in this patient subgroup. Stent placement may be considered depending on the patient’s antiplatelet status, angioplasty success, and concern for intracranial hemorrhage. Further studies amongst larger patient cohorts are needed.

Cardiac-gated intracranial elastance in a swine model of raised intracranial pressure: a novel method to assess intracranial pressure-volume dynamics.

Previous studies have demonstrated the importance of intracranial elastance; however, methodological difficulties have limited widespread clinical use. Measuring elastance may offer potential benefit in helping to identify patients at risk for untoward intracranial pressure (ICP) elevation from small rises in intracranial volume. The authors sought to develop an easily used method that accounts for the changing ICP that occurs over a cardiac cycle and to assess this method in a large-animal model over a broad range of ICPs. The authors used their previously described cardiac-gated intracranial balloon pump and swine model of cerebral edema. In the present experiment they measured elastance at 4 points along the cardiac cycle-early systole, peak systole, mid-diastole, and end diastole-by using rapid balloon inflation to 1 ml over an ICP range of 10-30 mm Hg. The authors studied 7 swine with increasing cerebral edema. Intracranial elastance rose progressively with increasing ICP. Peak-systolic and end-diastolic elastance demonstrated the most consistent rise in elastance as ICP increased. Cardiac-gated elastance measurements had markedly lower variance within swine compared with non-cardiac-gated measures. The slope of the ICP-elastance curve differed between swine. At ICP between 20 and 25 mm Hg, elastance varied between 8.7 and 15.8 mm Hg/ml, indicating that ICP alone cannot accurately predict intracranial elastance. Measuring intracranial elastance in a cardiac-gated manner is feasible and may offer an improved precision of measure. The authors' preliminary data suggest that because elastance values may vary at similar ICP levels, ICP alone may not necessarily best reflect the state of intracranial volume reserve capacity. Paired ICP-elastance measurements may offer benefit as an adjunct "early warning monitor" alerting to the risk of untoward ICP elevation in brain-injured patients that is induced by small increases in intracranial volume.

Hypertonic saline reduces cell infiltration into the lungs after brain death in rats

BackgroundLung transplantation is a treatment method for end stage lung disease, but the availability of donor lungs remains a major constraint. Brain death (BD) induces hemodynamic instability with microcirculatory hypoperfusion and increased inflammation, leading to pulmonary dysfunction. Hypertonic saline solution (HSS) is a volume expander possessing immunomodulatory effects. This study evaluated the influence of HSS on pulmonary dysfunction and inflammation in a rat model of BD. MethodsBD was induced by inflation of an intracranial balloon catheter. Rats were divided into [1]: Sham, without BD [2]; NS, NaCl treatment (0.9%, 4 mL/kg, i.v.) immediately after BD [3]; HSS1, HSS treatment (NaCl 7.5%, 4 mL/kg, i.v.) immediately after BD; and [4] HSS60, HSS treatment 60 min post BD. All groups were analyzed after 360 min. ResultsAnimals subjected to BD exhibited increased exhaled O2 and decreased CO2.The number of leukocytes in the lungs was significantly increased in the NS group (p = 0.002) and the HSS treatment was able to reduce it (HSS1, p = 0.018 and HSS60 = 0.030). In parallel, HSS-treated rats showed reduced levels of ICAM-1 expression, which was increased in the NS compared to Sham group. Lung edema was found increased in the NS group animals compared to Sham and no effect of the HSS treatment was observed. There were no differences among the groups in terms of TNF-α, VEGF, and CINC-1 lung concentrations. ConclusionsHSS is capable of reducing inflammatory cell infiltration into the lung after BD induction, which is associated with the reduction of ICAM-1 expression in organ vessels.

The influence of female sex hormones on lung inflammation after brain death - an experimental study.

Organ donor's age negatively influences graft survival of organs, increasing risk of complications. Aging occurs in both men and women; however, the menopause marks a decrease in sex hormones and a sudden increase in the process of vascular aging. We investigated sex hormones' influence on the lung inflammatory process induced by BD in female rats. Wistar rats were grouped as: female rats from high estradiol to heat period (non-OVx) and ovariectomized (OVx) female rats. Ovariectomy was carried out 10days before BD. BD was induced using intracranial balloon rapid inflation. Serum hormones and inflammatory mediators were quantified, leukocytes and platelets counted and lung samples were collected for RT-PCR, immunohistochemical, and histological analysis. Female sex hormones and corticosterone were reduced 6h after BD in non-OVx group. The infiltration of leukocytes in female non-OVx lungs was higher compared to OVx. G-CSF, VEGF, and CINC-1 were found increased in non-OVx group serum in comparison to OVx. Lung mediators were increased in non-OVx rats compared to controls. The acute reduction of sex hormones induced by BD appears to have a worse effect on lung inflammation than a reduction that has happened over a prolonged period of time, allowing a physiological adaptation prior to BD.

Preliminary Experience With Proximal Flow Reversal During Intracranial Balloon Angioplasty and Stenting for Symptomatic, Severe Intracranial Stenosis

Abstract INTRODUCTION The frequency of balloon-angioplasty and stenting for symptomatic intracranial stenosis was drastically reduced after publication of the negative SAMMPRIS trial. In part, this was due to a higher than expected periprocedural complication rate (14.7% 30-d stroke or death) compared to maximal medical therapy (5.8%). Although the cause of periprocedural stroke was not defined, intraprocedural artery-to-artery embolism is a likely contributor. The Silk Road ENROUTE Transcarotid Neuroprotection System (TCNS) was designed as an alternative revascularization strategy for carotid bifurcation disease. It provides direct transcarotid access and proximal protection through flow reversal. We adapted this system as a proximal protection strategy for balloon angioplasty and stenting of severe, symptomatic intracranial stenosis. METHODS From May-2017 to May-2019, 7 patients underwent intracranial balloon angioplasty and stenting for symptomatic intracranial stenosis using the TCNS. Baseline demographics, comorbidities, procedure-related parameters, and outcomes were assessed. RESULTS A total of 7 patients (mean age 63, SEM 4.7 yr, 57% female) with severe (84% +/− 5%) supraclinoid internal carotid artery (ICA) and/or M1 stenosis presented with recurrent strokes (86% left sided) despite dual antiplatelet therapy (DAPT). Angiographically, cessation or reversal of flow was seen in the supraclinoid ICA in all patients, with confirmation by transcranial doppler in selected cases, after the institution of flow reversal by the TCNS. A noncompliant balloon was used to perform submaximal angioplasty, followed by stenting with intracranial stents. All procedures were technically successful with no evidence of periprocedural thromboembolic complications. Follow-up ranged from 6 to 12 mo. One patient suffered a fatal reperfusion hemorrhage on POD 3. One patient suffered from a minor recurrent stroke at 7 mo (after the cessation of DAPT) and was restarted on DAPT. CONCLUSION Traditional methods of intracranial balloon angioplasty and stenting suffer from high periprocedural ischemic stroke rates. TCNS can be adapted to provide a means of proximal protection during the treatment of these high-risk lesions. This procedural innovation warrants further investigation.

Cerebral blood flow augmentation using a cardiac-gated intracranial pulsating balloon pump in a swine model of elevated ICP.

Augmenting brain perfusion or reducing intracranial pressure (ICP) dose is the end target of many therapies in the neuro-critical care unit. Many present therapies rely on aggressive systemic interventions that may lead to untoward effects. Previous studies have used a cardiac-gated intracranial balloon pump (ICBP) to model hydrocephalus or to flatten the ICP waveform. The authors sought to sought to optimize ICBP activation parameters to improve cerebral physiological parameters in a swine model of raised ICP. The authors developed a cardiac-gated ICBP in which the volume, timing, and duty cycle (time relative to a single cardiac cycle) of balloon inflation could be altered. They studied the ICBP in a swine model of elevated ICP attained by continuous intracranial fluid infusion with continuous monitoring of systemic and cerebral physiological parameters, and defined two specific protocols of ICBP activation. Eleven swine were studied, 3 of which were studied to define the optimal timing, volume, and duty cycle of balloon inflation. Eight swine were studied with two defined protocols at baseline and with ICP gradually raised to a mean of 30.5 mm Hg. ICBP activation caused a consistent modification of the ICP waveform. Two ICBP activation protocols were used. Balloon activation protocol A led to a consistent elevation in cerebral blood flow (8%-25% above baseline, p < 0.00001). Protocol B resulted in a modest reduction of ICP over time (8%-11%, p < 0.0001) at all ICP levels. Neither protocol significantly affected systemic physiological parameters. The preliminary results indicate that optimized protocols of ICBP activation may have beneficial effects on cerebral physiological parameters, with minimal effect on systemic parameters. Further studies are warranted to explore whether ICBP protocols may be of clinical benefit in patients with brain injuries with increased ICP.