Assessing changes in regional cerebral hemodynamics in adults with a high-density full-head coverage time-resolved near-infrared spectroscopy device.

Significance: Cerebral oximeters have the potential to detect abnormal cerebral blood oxygenation to allow for early intervention. However, current commercial systems have two major limitations: (1) spatial coverage of only the frontal region, assuming that surgery-related hemodynamic effects are global and (2) susceptibility to extracerebral signal contamination inherent to continuous-wave near-infrared spectroscopy (NIRS). Aim: This work aimed to assess the feasibility of a high-density, time-resolved (tr) NIRS device (Kernel Flow) to monitor regional oxygenation changes across the cerebral cortex during surgery. Approach: The Flow system was assessed using two protocols. First, digital carotid compression was applied to healthy volunteers to cause a rapid oxygenation decrease across the ipsilateral hemisphere without affecting the contralateral side. Next, the system was used on patients undergoing shoulder surgery to provide continuous monitoring of cerebral oxygenation. In both protocols, the improved depth sensitivity of trNIRS was investigated by applying moment analysis. A dynamic wavelet filtering approach was also developed to remove observed temperature-induced signal drifts. Results: In the first protocol (28±5 years; five females, five males), hair significantly impacted regional sensitivity; however, the enhanced depth sensitivity of trNIRS was able to separate brain and scalp responses in the frontal region. Regional sensitivity was improved in the clinical study given the age-related reduction in hair density of the patients (65±15 years; 14 females, 13 males). In five patients who received phenylephrine to treat hypotension, different scalp and brain oxygenation responses were apparent, although no regional differences were observed. Conclusions: The Kernel Flow has promise as an intraoperative neuromonitoring device. Although regional sensitivity was affected by hair color and density, enhanced depth sensitivity of trNIRS was able to resolve differences in scalp and brain oxygenation responses in both protocols.

Intermittent Manual Carotid Compression as a Treatment Option for Indirect Low Flow Carotid Cavernous Fistula.

PURPOSE: To evaluate the efficacy of intermittent manual carotid compression (IMCC) in the management of low-flow carotid cavernous fistulae (CCF). MATERIALS AND METHODS: Patients diagnosed with low-flow CCF and treated with IMCC over a period of 13 years were retrospectively analyzed. Data analyzed included demographic details, clinical features, type of CCF, and response to therapy. Outcomes were categorized as complete cure, partial cure, and no cure or worsening. Patients with complete and partial cure were grouped as good outcome whereas those with no cure or worsening as poor outcome. RESULTS: A total of 44 patients were advised IMCC for low-flow CCF, of whom five were lost to follow-up. Results of the remaining 39 patients were analyzed, of whom 21 (53.8%) were males. The mean age at presentation was 54.38 ± 14.54 years. The median duration between the onset of symptoms and presentation was 5.0 ± 4.10 months. The common presenting features were episcleral congestion and proptosis (89.7%), extraocular motility restriction (66.7%), and diplopia (48.7%). Most common CCF type was type D (34, 87.2%). All patients were advised to undergo IMCC. Good outcome was seen in 35 patients (89.7%, 95% CI: 80.2% to 99.2%), whereas poor outcome was seen in four (10.3%) patients. The mean duration of follow-up was 15.91 ± 21.87 months. CONCLUSION: The present study found a good outcome with IMCC in 89.7% cases of indirect low-flow CCF with no major complications. It should be considered the management of choice in patients who are systemically unfit or cannot afford endovascular embolization.

Assessing the Sensitivity of Multi-Distance Hyperspectral NIRS to Changes in the Oxidation State of Cytochrome C Oxidase in the Brain.

Near-infrared spectroscopy (NIRS) measurements of tissue oxygen saturation (StO2) are frequently used during vascular and cardiac surgeries as a non-invasive means of assessing brain health; however, signal contamination from extracerebral tissues remains a concern. As an alternative, hyperspectral (hs)NIRS can be used to measure changes in the oxidation state of cytochrome c oxidase (ΔoxCCO), which provides greater sensitivity to the brain given its higher mitochondrial concentration versus the scalp. The purpose of this study was to evaluate the depth sensitivity of the oxCCO signal to changes occurring in the brain and extracerebral tissue components. The oxCCO assessment was conducted using multi-distance hsNIRS (source-detector separations = 1 and 3 cm), and metabolic changes were compared to changes in StO2. Ten participants were monitored using an in-house system combining hsNIRS and diffuse correlation spectroscopy (DCS). Data were acquired during carotid compression (CC) to reduce blood flow and hypercapnia to increase flow. Reducing blood flow by CC resulted in a significant decrease in oxCCO measured at rSD = 3 cm but not at 1 cm. In contrast, significant changes in StO2 were found at both distances. Hypercapnia caused significant increases in StO2 and oxCCO at rSD = 3 cm, but not at 1 cm. Extracerebral contamination resulted in elevated StO2 but not oxCCO after hypercapnia, which was significantly reduced by applying regression analysis. This study demonstrated that oxCCO was less sensitive to extracerebral signals than StO2.

Manual Carotid Compression is a Viable Alternative for Reduction of Cerebral Microemboli.

BACKGROUND: Stroke is a devastating complication of cardiovascular surgeries, and the risk is particularly high for those requiring cardiopulmonary bypass (CPB). Embolic particles generated during the unclamping of the aortic cross-clamp may enter the cerebral circulation, lodging in small vessels. External manual compression of the carotid arteries is a non-invasive technique that has been proposed for cerebral protection during CPB procedures but is not widely deployed. METHODS: The aim of this study is to assess the potential for cerebral emboli reduction with carotid compression using an in vitro model. Experiments were performed with a glass aortic arch model in a mock cardiovascular circuit. Small fluorescent particles were released into the circulation with and without carotid compression, and the particles visualized in the aortic midplane. The number of particles in the aorta and arch branch vessels were counted from the images before, during and following the release of carotid compression for durations of 10, 15 and 20 s. A gamma variate function was fit to the data to describe the bolus dynamics. RESULTS: Carotid compression for 10 s reduces the number of embolic articles entering the carotid arteries by over 75%. A compression duration of 15-20 s does not result in greater particle reduction than one of 10 s. CONCLUSION: Brief compression of the common carotid arteries during cardiovascular interventions has the potential to dramatically reduce the number of cerebral emboli and should be investigated further.

Superior ophthalmic vein thrombosis post manual carotid compression for indirect carotid-cavernous fistula.

PURPOSE: To report 5 cases of superior ophthalmic vein thrombosis (SOVT) following intermittent manual carotid compression (IMCC) for indirect carotid-cavernous fistula (CCF) and to outline the management. METHODS: Retrospective observational case series of all patients who developed SOVT secondary to IMCC for indirect low flow CCF's at a tertiary care center. The demographic profile, clinical, imaging findings, treatment, and outcomes were studied. RESULTS: The mean age at presentation was 60.2 years (Range: 42-87 years). Four patients were male. All patients had a unilateral presentation. The mean time interval between starting IMCC and the development of SOVT was 1.18 months (Range: 0.25-3 months). Acute exacerbation of proptosis and chemosis associated with a decrease in vision was the presenting feature in all the patients. The mean visual acuity at presentation was 0.89 on the logMAR scale. The causes of reduced visual acuity were venous stasis retinopathy (n = 4) and compressive optic neuropathy (n = 1). Magnetic resonance imaging revealed enlarged superior ophthalmic vein with absent flow voids and post-contrast filling defects. Four patients received anticoagulation treatment with subcutaneous injection of enoxaparin 1 mg/kg twice daily for 5 days followed by oral warfarin 5 mg once daily along with oral steroids. Complete recovery of SOVT was noted in all patients at a mean duration of treatment of 0. 75 months (Range: 0-2 months). CONCLUSION: SOVT is a rare but possible complication in patients on IMCC for indirect CCF, and hence warrants close follow up. Early diagnosis and prompt management will help in preventing complications like permanent vision loss.

Usefulness of External Carotid Artery Angiogram with Manual Carotid Compression in Ophthalmic Artery Aneurysm.

OBJECTIVE: Identifying collaterals from external carotid artery (ECA) is necessary before treatment of ophthalmic artery (OphA) aneurysm. We present a manual carotid compression test to verify collaterals in ophthalmic artery aneurysms, and evaluate its usefulness. MATERIALS AND METHODS: From March 2013 to December 2017, endovascular coiling was performed 19 consecutive patients with 20 OphA aneurysms. We performed manual carotid compression test for patients who had aneurysms incorporating entry of OphA. Clinical and angiographic outcomes were investigated. RESULTS: Of 13 cases underwent manual carotid compression test, 12 cases were confirmed collateral flow from ECA to OphA. During the coil embolization, we tried to maintain the original OphA flow even if it has a collateral anastomosis. Among them, OphA occlusion occurred in one patient during coiling. Recurrence of aneurysm was occurred in a ruptured case and additional embolization was required. CONCLUSIONS: The manual carotid compression test is useful method to identify the collaterals from ECA in patients with OphA aneurysm. This test can be used as a screening test for confirming collateral flow in OphA aneurysms or as an alternative for patients who are difficult to perform BTO.

Usefulness of External Carotid Artery Angiogram with Manual Carotid Compression in Ophthalmic Artery Aneurysm

OBJECTIVE: Identifying collaterals from external carotid artery (ECA) is necessary before treatment of ophthalmic artery (OphA) aneurysm. We present a manual carotid compression test to verify collaterals in ophthalmic artery aneurysms, and evaluate its usefulness.MATERIALS AND METHODS: From March 2013 to December 2017, endovascular coiling was performed 19 consecutive patients with 20 OphA aneurysms. We performed manual carotid compression test for patients who had aneurysms incorporating entry of OphA. Clinical and angiographic outcomes were investigated.RESULTS: Of 13 cases underwent manual carotid compression test, 12 cases were confirmed collateral flow from ECA to OphA. During the coil embolization, we tried to maintain the original OphA flow even if it has a collateral anastomosis. Among them, OphA occlusion occurred in one patient during coiling. Recurrence of aneurysm was occurred in a ruptured case and additional embolization was required.CONCLUSIONS: The manual carotid compression test is useful method to identify the collaterals from ECA in patients with OphA aneurysm. This test can be used as a screening test for confirming collateral flow in OphA aneurysms or as an alternative for patients who are difficult to perform BTO.

Digital Carotid Compression: A Simple Method to Reduce Solid Cerebral Emboli During Cardiac Surgery.

OBJECTIVES: Serious neurologic injury can be attributed to embolization of solid particles into cerebral vessels during cardiac surgery. Previous studies using transcranial Doppler (TCD) identified arterial cannulation and aortic declamping to be associated with cerebral embolization. The purpose of this study was to investigate the impact of transient compression of the carotid arteries during these maneuvers on the embolic load during cardiac surgery with cardiopulmonary bypass. DESIGN: Prospective, randomized, clinical trial/pilot study. SETTING: Single-center study at a university hospital. PARTICIPANTS: Patients with multiple types of procedures were included and they were prospectively, randomly assigned to group I (n = 20, carotid compression during arterial cannulation and aortic declamping) and group II (n = 20, no carotid compression). INTERVENTIONS: Bilateral continuous monitoring of the middle cerebral arteries was performed with a multirange, multifreqency transcranial Doppler (DopplerBoxX, DWL, Singen, Germany), allowing for discrimination between solid and gaseous emboli. For aortic cannulation the carotid arteries were compressed for 5 seconds and for declamping for 3 seconds, and microemboli signals were detected within the following 45 seconds. MEASUREMENTS AND MAIN RESULTS: A reduction of intraoperative solid emboli was detected in group I compared with group II (26±16 v 38±18; p = 0.04). Looking specifically at the maneuver of arterial cannulation, the observed difference was 0.5±0.8 in group I versus 5.7±5.8 in group II (p<0.0001). During aortic declamping, 6.6±6.2 emboli were encountered in group I and 10.8±5.2 in group II (p = 0.02). The incidence of neurologic events was not significantly different between groups (2 patients in group II had pathologic changes on magnetic resonance imaging). CONCLUSIONS: The data of this preliminary trial demonstrated that transient compression of the carotid arteries during arterial cannulation and aortic declamping led to a decreased number of solid cerebral emboli. Further prospective, randomized clinical studies should be undertaken to investigate the influence of transient carotid artery compression during specific surgical procedures.

A manual carotid compression technique to overcome difficult filter protection device retrieval during carotid artery stenting.

BACKGROUND: We investigated the incidence of embolic protection device retrieval difficulties at carotid artery stenting (CAS) with a closed-cell stent and demonstrated the usefulness of a manual carotid compression assist technique. METHODS: Between July 2010 and October 2013, we performed 156 CAS procedures using self-expandable closed-cell stents. All procedures were performed with the aid of a filter design embolic protection device. We used FilterWire EZ in 118 procedures and SpiderFX in 38 procedures. The embolic protection device was usually retrieved by the accessory retrieval sheath after CAS. We applied a manual carotid compression technique when it was difficult to navigate the retrieval sheath through the deployed stent. We compared clinical outcomes in patients where simple retrieval was possible with patients where the manual carotid compression assisted technique was used for retrieval. RESULTS: Among the 156 CAS procedures, we encountered 12 (7.7%) where embolic protection device retrieval was hampered at the proximal stent terminus. Our manual carotid compression technique overcame this difficulty without eliciting neurologic events, artery dissection, or stent deformity. CONCLUSIONS: In patients undergoing closed-cell stent placement, embolic protection device retrieval difficulties may be encountered at the proximal stent terminus. Manual carotid compression assisted retrieval is an easy, readily available solution to overcome these difficulties.

A Case of Recurrent Cerebral Infarction due to Carotid Compression by a Neurogenic Tumor in the Neck / 대한뇌졸중학회지

A 62-year-old man with a neurogenic tumor in the neck was admitted to our hospital for recurrent ischemic stroke due to carotid occlusion. The magnetic resonance (MR) angiograms revealed the occlusion of the right internal carotid artery (ICA). Arterial compression by the tumor could be considered as the cause of ICA occlusion. Since neurogenic tumors of the neck have significant surgical risks, the patient underwent extracranial-intracranial arterial bypass (EC-IC bypass) surgery. We report a case with recurrent ischemic stroke due to carotid compression by a neurogenic tumor of the neck.