Carotid Sinus Research Articles

Elderly patient with syncope: the clinical case

Recurrent syncope in the elderly is of particular concern to the clinician. Differential diagnosis of syncope in such patients presents significant difficulties due to high comorbidity. For patients over 70 years old, an increased number of syncopal episodes is typical; syncope becomes one of the leading reasons for their emergency hospitalization. The importance of determining the exact cause of syncope in this case cannot be overestimated: frequent falls significantly reduce the quality of life and can lead to serious injuries or even be fatal. Therefore, today it is critically important to have modern diagnostic methods that can help determine the etiology of syncope. The presented clinical case demonstrates a diagnostic search using continuous non-invasive “beat-to-beat” blood pressure measurement methods during such provocative tests as a passive orthostatic test and a carotid sinus massage. This technique is used routinely in the USA and European countries but is not enough widespread in the Russian Federation. Such a tool may simplify the differential diagnosis of syncope.

The effect of block side on hemodynamic and respiratory parameters in patients who had interscalene block for upper limb surgery.

The administration of interscalene block (ISB) may lead to several hemodynamic effects, likely due to the diffusion of local anesthetic to nearby structures such as carotid sinus baroreceptors. This study aimed to compare hemodynamic and respiratory changes resulting from right and left-sided ISB. A retrospective analysis was conducted on adults who had ultrasound-guided ISB for upper limb surgery between January 2020 and December 2021. All patients had ISB with bupivacaine 0.5% and lidocaine 2% mixture following premedication. Demographic data, arterial blood pressure, heart rate, and peripheral oxygen saturation (SpO2) were measured before and after the block at regular intervals. Block characteristics, surgical and post-anesthesia care unit (PACU) durations, intraoperative analgesic requirements, and side effects were analyzed. A total of 94 patients had ISB for upper limb surgery, 54 for the right and 40 for the left-sided surgeries. Patients' data were analyzed in two groups according to the block side. Increased arterial blood pressure was observed in both groups after the block compared to the control values. Systolic arterial pressure from 10 to 30 minutes, diastolic arterial pressure at the 25th minute, and mean arterial pressure at the 15th, 20th, and 25th minutes were significantly higher on the right-sided blocks. Heart rate, SpO2, analgesic requirements, block characteristics, and PACU durations did not differ between the groups. Ultrasound-guided ISB-applied patients demonstrated increased blood pressure compared to control values. This increase, without concurrent changes in heart rate, was more pronounced in right-sided ISB. These findings indicate that careful hemodynamic monitoring is necessary whenever hypertension should be avoided for the patients.

Carotid Web – An Unusual Cause for Ischemic Stroke in a Young Woman

Abstract Carotid web (CW) is a rare condition where a shelf-like projection of intimal fibrous tissue is seen arising from the posterior wall of the carotid bulb. It is regarded as a high-risk factor for ischemic stroke of undetermined etiology. Although there is no clear consensus as to the management of these patients, the published literature is more in favor of intervention rather than medical management due to the higher incidence of recurrent stroke in conservatively managed patients. We present a case of a young woman with ischemic stroke due to CW who was managed successfully with thrombolysis followed by endovascular management.

A cross-sectional nationwide survey of guideline based syncope units in the Netherlands: the SU-19 score-a novel validation for best practices.

We aimed to identify all syncope units (SUs) in the Netherlands and assess the extent to which these SUs fulfil the essential requirements outlined by the consensus statements of the European Heart Rhythm Association and the European Society of Cardiology syncope guidelines. For this, we developed the SU-19 score, a novel guideline based validation tool for best practice. All outpatient clinics of cardiology, neurology, and internal medicine in the Netherlands were screened for presence of any form of structured specialized syncope care. If present, these were included as SUs and requested to complete a questionnaire regarding syncope care. We assessed all SUs using the SU-19 score regarding structure (3 points), available tests (12 points), and initial evaluation (4 points). Twenty SUs were identified in the Netherlands, both academic (5/20) and non-academic hospitals (15/20), 17/20 reported multidisciplinary involvement during initial evaluation. In 19/20, neurology, cardiology, or both were responsible for the syncope management. Non-physicians were involved performing the head-up tilt test (44%) and initial evaluation (40%). The mean SU-19 score was 18.0 ± 1.1, 45% achieved the maximum score of 19 points. Variations were observed in protocols for active standing test, carotid sinus massage, and head-up tilt test. There is a network of 20 SUs in the Netherlands. Forty-five per cent fully met the SU-19 score (mean 18.0 ± 1.1). Slight variety existed in protocols for autonomic function tests. Neurology and cardiology were mostly involved in syncope management. Non-physicians play an important role in syncope care.

Carotid body denervation improves hyperglycemia in obese mice.

The carotid bodies (CBs) have been implicated in glucose abnormalities in obesity via elevation of activity of the sympathetic nervous system. Obesity-induced hypertension is mediated by insulin receptor (INSR) signaling and by leptin, which binds to the leptin receptor (LEPRb) in CB and activates transient receptor potential channel subfamily M member 7 (TRPM7). We hypothesize that in mice with diet-induced obesity, hyperglycemia, glucose intolerance, and insulin resistance will be attenuated by the CB denervation (carotid sinus nerve dissection, CSND) and by knockdown of Leprb, Trpm7, and Insr gene expression in CB. In series of experiments in 75 male diet-induced obese (DIO) mice, we performed either CSND (vs. sham) surgeries or shRNA-induced suppression of Leprb, Trpm7, or Insr gene expression in CB, followed by blood pressure telemetry, intraperitoneal glucose tolerance and insulin tolerance tests, and measurements of fasting plasma insulin, leptin, corticosterone, glucagon and free fatty acids (FFAs) levels, hepatic expression of gluconeogenesis enzymes phosphoenolpyruvate carboxykinase (PEPCK) and glucose 6-phosphatase (G-6-Pase) mRNA and liver glycogen levels. CSND decreased blood pressure, fasting blood glucose levels and improved glucose tolerance without any effect on insulin resistance. CSND did not affect any hormone levels and gluconeogenesis enzymes, but increased liver glycogen level. Genetic knockdown of CB Leprb, Trpm7, and Insr had no effect on glucose metabolism. We conclude that CB contributes to hyperglycemia of obesity, probably by modulation of the glycogen-glucose equilibrium. Diabetogenic effects of obesity on CB in mice do not occur via activation of CB Leprb, Trpm7, and Insr.NEW & NOTEWORTHY This paper provides first evidence that carotid body denervation abolishes hypertension and improves fasting blood glucose levels and glucose tolerance in mice with diet-induced obesity. Furthermore, we have shown that this phenomenon is associated with increased liver glycogen content, whereas insulin sensitivity and enzymes of gluconeogenesis were not affected.

Breakthrough of dual-phase CT angiography features of carotid web and its correlation with ischemic stroke

PurposeTo investigate the diagnostic value of dual phase CT angiography (CTA) in carotid web and its correlation with ischemic stroke. MethodsThe imaging data of 726 patients with cervical CTA from January 2015 to November 2019 in Taizhou People's hospital were retrospectively and consecutively analyzed. A total of 16 patients with 23 carotid webs were obtained. The location, morphology and clinical data of 16 patients were observed. Carotid web was identified by two experienced radioimaging experts according to the characteristics of a thin intraluminal filling defect along the posterior wall of the carotid bulb on sagittal CTA and a septum structure in arteries on axial CTA. ResultsIn the arterial phase, 23 carotid webs in 16 patients showed membrane like separation in the lumen of the posterior wall of the carotid bulb, and one web extended into the internal and external carotid arteries in a "Y" shape. There were 9 males and 7 females. In venous phase, 16 carotid webs showed linear enhancement, and 15 sites showed delayed emptying of contrast medium at the lateral margin. Five patients were acute or chronic ischemic stroke. The kappa coefficient for interobserver agreement in diagnosing carotid web was 0.79. ConclusionDual-phase CTA is effective and reliable method to identifying carotid webs, which may be associated with ischemic stroke.

Input-size dependence of the baroreflex neural arc transfer characteristics during Gaussian white noise inputs.

Although Gaussian white noise (GWN) inputs offer a theoretical framework for identifying higher-order nonlinearity, an actual application to the data of the neural arc of the carotid sinus baroreflex did not succeed in fully predicting the well-known sigmoidal nonlinearity. In the present study, we assumed that the neural arc can be approximated by a cascade of a linear dynamic (LD) component and a nonlinear static (NS) component. We analyzed the data obtained using GWN inputs with a mean of 120 mmHg and standard deviations (SDs) of 10, 20, and 30 mmHg for 15 min each in anesthetized rats (n = 7). We first estimated the linear transfer function from carotid sinus pressure to sympathetic nerve activity (SNA) and then plotted the measured SNA against the linearly predicted SNA. The predicted and measured data pairs exhibited an inverse sigmoidal distribution when grouped into 10 bins based on the size of the linearly predicted SNA. The sigmoidal nonlinearity estimated via the LD-NS model showed a midpoint pressure (104.1 ± 4.4 mmHg for SD of 30 mmHg) lower than that estimated by a conventional stepwise input (135.8 ± 3.9 mmHg, P < 0.001). This suggests that the NS component is more likely to reflect the nonlinearity observed during pulsatile inputs that are physiological to baroreceptors. Furthermore, the LD-NS model yielded higher R2 values compared with the linear model and the previously suggested second-order Uryson model in the testing dataset.NEW & NOTEWORTHY We examined the input-size dependence of the baroreflex neural arc transfer characteristics during Gaussian white noise inputs. A linear dynamic-static nonlinear model yielded higher R2 values compared with a linear model and captured the well-known sigmoidal nonlinearity of the neural arc, indicating that the nonlinear dynamics contributed to determining sympathetic nerve activity. Ignoring such nonlinear dynamics might reduce our ability to explain underlying physiology and significantly limit the interpretation of experimental data.

Internal carotid bulb occlusion by a giant thrombus after thoracoscopic left upper lung lobectomy successfully treated with endovascular stenting: a case report

BackgroundPerioperative acute ischemic stroke following lung resection is relatively rare, though a devastating complication. Specifically, patients undergoing left upper lung lobectomy for lung cancer are likely to develop perioperative acute ischemic stroke.Case presentationA 67-year-old man underwent thoracoscopic left upper lung lobectomy for lung adenocarcinoma; he experienced sudden-onset left hemiparesis and dysarthria on the morning of the second postoperative day. Angiography revealed occlusion of the bulbs of the right internal and external carotid arteries by a giant thrombus, which could not be removed through endovascular thrombectomy. We deployed a stent at the right carotid bifurcation to foist the giant thrombus, achieving revascularization 4 h after the onset. Treatment response was assessed as good improvement with a modified Rankin scale score of 0, and the patient was discharged home 19 days after symptom onset.ConclusionsWe present a unique case of carotid bulb thromboembolism resulting from a giant thrombus following thoracoscopic left upper lung lobectomy, for which endovascular stenting was effective.

Optical Coherence Tomography in the Evaluation of Suspected Carotid Webs

BackgroundCarotid web (CaW) is a subtype of fibromuscular dysplasia that predominantly involves the intimal layer of the arterial wall and is commonly overlooked as a separate causative entity for recurrent...

A comparison of intima media thickness in the common carotid artery, the bulb and plaque area as predictions of incident atherosclerotic events.

There is a debate on how to evaluate carotid artery intima-media thickness (IMT). We here compared IMT of the common carotid artery (CCA) and bulb with plaque area regarding incident atherosclerotic disease. In the PIVUS study (age 70 at baseline, 53% women, n = 856), IMT-CCA, IMT-bulb and plaque area were measured at ages 70, 75 and 80 years and these three measurements were used in updated Cox proportional hazard analysis. Over 15 years follow-up, 135 individuals experienced a first-time atherosclerotic disease (myocardial infarction or ischemic stroke). IMT-CCA was not significantly related to this composite endpoint (p = 0.10). IMT-bulb was significantly related to the endpoint (p = 0.003), but this relationship was attenuated following adjustment for CVD risk factors (p = 0.02). On the contrary, plaque area was consistently related to incident atherosclerotic disease also following adjustment for CVD risk factors (p<0.001). When added on top of traditional risk factors, both IMT-bulb and plaque area, but not IMT-CCA, improved the discrimination compared to the traditional risk factors (+5.2%, p = 0.0026 for IMT-bulb, +3.8%, p = 0.013 for plaque area and 0.0% for IMT-CCA). In elderly subjects, both IMT-bulb and plaque area improved the discrimination regarding incident atherosclerotic disease when added to traditional risk factors. This was not seen for IMT-CCA. IMT-CCA was therefore inferior compared to the other two carotid artery ultrasonographic measurements in this sample of elderly subjects.

Electrical carotid sinus nerve stimulation attenuates experimental colitis induced by acetic acid in rats

AimsThe carotid bodies are sensors that detect physiological signals and convey them to the central nervous system, where the stimuli are processed inducing reflexes through efferent pathways. Recent studies have demonstrated that electrical stimulation of the carotid sinus nerve (CSN) triggers the anti-inflammatory reflex under different conditions. However, whether this electrical stimulation attenuates colitis was never examined. This study aimed to evaluate if the electrical CSN stimulation attenuates the experimental colitis induced by intrarectal administration of acetic acid in rats. MethodsElectrodes were implanted around the CSN to stimulate the CSN, and a catheter was inserted into the left femoral artery to record the arterial pressure. The observation of hypotensive responses confirmed the effectiveness of the electrical CNS stimulation. This maneuver was followed by a 4 % acetic acid or saline administered intrarectally. After 24 h, colons were segmented into distal and proximal parts for macroscopy, histological and biochemical assessment. Key findingsAs expected, the electrical CSN stimulation was effective in decreasing arterial pressure in saline and colitis rats. Moreover, electrical CSN stimulation effectively reduced colonic tissue lesions, colitis scores, and histopathologic parameters associated with colitis. In addition, the CSN stimulation also reduced the colonic mucosa pro-inflammatory cytokine interleukin-1 beta, and increased the anti-inflammatory interleukin-10, in rats submitted to colitis. SignificanceThese findings indicated that electrical CSN stimulation breaks the vicious cycle of local colon inflammation in colitis, which might contribute to its better outcome.

Impact on hemodynamics in carotid arteries with carotid webs at different locations: A Numerical Study Integrating Thrombus Growth Model

ObjectiveCarotid webs (CWs), lesions in the carotid arteries, are gaining research interest due to the unclear link to ischemic stroke. Similarity to atherosclerosis in lesion location adds the complexity. The main purpose of study is to investigate the hemodynamic effects of CWs at different locations in carotid arteries. MethodsThree types of models with CWs were reconstructed from the CTA dataset of 8 healthy carotid arteries (Models A: CWs at the common carotid artery; B: at the origin of internal carotid artery; C: at the carotid sinus). Wall shear stress (WSS)-based parameters, including time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), relative residence time (RRT), and endothelial cell activation potential (ECAP) were analyzed. A thrombus growth model was also incorporated to assess long-term thrombus formation across different carotid webs locations. ResultsModels A exhibited helical flow, whereas models B and C showed disturbed flow in the carotid sinus. Recirculation in Models A and B was mainly downstream of CWs, while Models C had both upstream and downstream recirculation. In addition, models A had higher overall TAWSS levels, with the smallest region of TAWSS < 0.4 pa (7.78 ± 8.35%). In contrast, Models C had larger areas with TAWSS < 0.4 pa, RRT > 100, and ECAP > 1.5, accounting for 14.18 ± 5.28%, 1.51 ± 1.17%, and 10.36 ± 4.10%, respectively. Noting that thrombus volume was highest in Models C (7.20 ± 3.95%). ConclusionsNumerical simulations indicate that: 1) CWs have less hemodynamic impact when located in the CCA, but may increase flow resistance leading to distal branch ischemia; 2) CWs contribute to thrombus formation, primarily downstream in the common carotid artery and internal carotid artery origin, and both upstream and downstream in the sinus; 3) CWs at the origin of the ICA are more likely to result in disturbed blood flow patterns and thrombus aggregation than the other two locations, which may increase the risk of ischemic stroke in distal cerebral arteries.

Head-up tilt test induced asystole and recurrent syncope: a follow-up study

Abstract Introduction Head-up tilt test (HUTT) is a valuable diagnostic tool in unexplained and recurrent syncope, especially when reflex etiology is suspected. If asystole is the dominant feature of reflex syncope, permanent pacemaker therapy may be effective for reducing syncope recurrence. Purpose To investigate syncope recurrence, pacemaker implantation and death of patients with syncope and asystole induced by HUTT and carotid sinus message (CSM). Methods Retrospective analysis of consecutive patients referred for HUTT between January 2017 and December 2021 and selection of those with cardioinhibitory response, defined by syncope or pre-syncope and asystolic pause ≥3 seconds. Patients’ follow-up (FUP) was performed via a phone interview and analysis of clinical records, to assess recurrence of syncope, treatments, and death. Results A total of 44 patients were included: 30 (68,2%) were men, with a median age of 69 years (interquartile range (IQR) of 24). Asystole was experienced after CSMin 41 patients and during tilt test alone in 3 patients. Median FUP was 26 months (IQR 23). There were 19 (44,2%) patients who implanted pacemaker (PM), all with cardioinhibitory carotid sinus syndrome ( I-CSS), 57,9% men, with median age of 74 years (IQR 19) and median duration of asystole during CSMof 6,3 seconds (IQR 3,8). Of these, 5 (26,3%) implanted a unicameral PM and the remaininga bicameral PM, with AAI-DDD mode programming. Two patients had PM-related complications: infection and dislodgment of ventricular lead, both in the first 15 days after implantation. Median atrial and ventricular pacing percentage at last PM consultation was 7% (IQR 28) and 1% (IQR 4), respectively. There was a positive strong correlation between the percentage of atrial pacing at first and at last appointment (p&amp;lt;0,001, r=0,867) and a positive moderated correlation between the percentage of ventricular pacingat first and at last appointment (p=0,022, r=0,586), suggesting a similar degree of pacing along FUP-time. Only three patients (6,8%) had syncope recurrence, all men with CI-CSS, median age of 78; one patient had syncope before implantation PM, other relapsed 2-times with a PMimplanted and the third refused PMimplantation despite 5-time recurrence of symptoms. There was no association between the duration of the asystole during HUTT with implantation of PM nor syncope recurrence (p&amp;gt;0.2). Age at HUTT was significantly associated both with CI-CSS and PM implantation (p=0,001 and p=0,045, respectively). Two patients died, both of oncologic causes. Conclusion In agreement with the literature, our cohort of patients with cardioinhibitory response during HUTT and CSM experienced an overall good prognosis, with no cardiac deaths; there was very low syncope recurrence, not allowing a comparison between the groups with and without pacemaker. Age at HUTT was significantly associated both with CI-CSS and PMimplantation.

Diagnostic approach at specialized syncope units in the netherlands: a cross-sectional, nationwide survey

Abstract Introduction The European Society of Cardiology Guidelines recommend a structural approach for the initial evaluation of syncope patients, yet implementation of such approach appears cumbersome. There are several specialized Syncope Units in the Netherlands. Here we investigated the diagnostic strategy of specialized Syncope Units and adherence areas for syncope patients. Purpose We aimed to identify the current network of Syncope Units in the Netherlands and to assess to which extent the units fulfil requirements as indicated by the European Heart Rhythm Association consensus and the current guidelines. Methods All units Neurology, Internal Medicine, and Cardiology in hospitals in the Netherlands were contacted. Units with specialized Syncope care were included and requested to fill out a questionnaire of 25 questions regarding which medical specialties are involved during evaluation, which diagnostic tests are available and being performed and which adherence regions were associated. We specifically investigated whether the Syncope Units adhered to the consensus statements 1 and 3 as described by the European Heart Rhythm Association position paper as gold standard for best practices. Results Specialized care for syncope was reported in 20/72 hospitals. Most (17/20) reported that multiple specialties are involved during the initial evaluation. 19/20 had either Neurology, Cardiology, or both responsible for the Syncope Unit. 18/20 perform guideline-based orthostatic blood pressure measurement. A non-invasive-beat-to-beat blood pressure monitor was present in 11/20 units. 16/20 perform tilt table testing and do &amp;gt; 48 per year, 3/16 this was during the initial evaluation and 15/20 perform carotid sinus massage. The adherence areas cover 64.2% of the Netherlands. Both European Heart Rhythm Association consensus statements 1 and 3 for best practice were met in 4/20 of the Syncope Units, 4/20 only met consensus statement 1 and 14/20 only met consensus statement 3. Conclusion We identified 20 Syncope Units in the Netherlands. The diagnostic approach varies in the medical specialties involved, protocols for cardiovascular testing, and timing of diagnostic tests. Most units did not completely perform the Guideline suggested initial evaluation. Four out of 20 Syncope Units met the European Heart Rhythm Association consensus statements for best clinical practice.Overview Syncope Units NetherlandsAdherence of the Syncope Unit

Abstract 11832: Carotid Sinus Massage Can Obviate the Need for Tilt Table Testing in Patients With Undiagnosed Vasodepressor Syncope

Introduction: Head-up tilt table (HUTT) testing is typically utilized for patients with syncope where the diagnosis is unclear but suspicion of a vasovagal etiology. Carotid sinus massage (CSM) can be used to elicit a vasopressor response though typically used to diagnose carotid sinus hypersensitivity. The usual protocol of HUTT consists of baseline CSM, 30-mins of HUTT, a repeat of CSM, and drug infusion. This is time-consuming and tedious. Hypothesis: CSM has a high predictive value for a vasodepressor response and may prevent the need for the completion of the HUTT protocol. Methods: Consecutive patients with clinical suspicion of vasovagal syncope underwent HUTT. Protocol consisted of baseline CSM in the supine posture, 30-mins of HUTT at 60 degrees, repeat CSM, and infusion of isoproterenol infusion from 1 to 3 mcg/min. Beat-to-beat blood pressure (BP) monitoring was performed non-invasively and standard cuff BP monitoring every minute. Positive tilt was defined as a drop in BP by more than 20 mmHg with reproducible symptoms (correlation to clinical symptoms). Results: 55 consecutive patients with a history of syncopal episode(s) underwent HUTT. 46 were females and 9 were male with a mean age of 54.4 ± 17.4 years old. They presented symptoms suggestive of a vasovagal etiology but were not diagnostic. 12 out of 55 (21.8%) patients had a positive reproducible response with supine CSM. 11 out of 12 of these patients subsequently had a positive result with protocol completion. This provided a positive predictive value (PPV) of 92%. 36 out of 55 (65.5%) patients had a negative response to CSM. All 36 had a negative result on completion of the HUTT protocol. This provided a negative predictive value (NPV) of 100%. 7 out of 55 (12.7%) patients had a “borderline” positive supine CSM. All 7 had a positive result with the completion of the HUTT protocol. Of note, these patients became positive only with isoproterenol infusion. Conclusions: CSM in the supine posture has a high PPV and NPV in eliciting a possible vasodepressor etiology. A full HUTT protocol may be only required in a patient who presents with a “borderline” CSM response in the supine posture. Therefore, CSM may easily be performed at the bedside with a monitor and a BP apparatus obviating the need for the full HUTT protocol.

Abstract 14807: Direct Carotid Sinus Nerve Stimulation in Anesthetized Human Subjects

Introduction: Drug resistant hypertension is a growing clinical phenomenon across the world and there is a critical need for alternative therapeutic modalities. Hypothesis: A novel multi-contact electrode designed to interface with the carotid sinus nerve in conjunction with a unique implantation technique can selectively activate the baroreflex causing reversible drops in blood pressure (BP) &amp; heart rate (HR) in anesthetized humans. Methods: Patients undergoing therapeutic operations that necessitated carotid bulb exposure were prospectively enrolled in this IRB approved trial. Using a novel surgical approach, an application specific electrode was placed around the CSN followed by contact interface mapping to identify presumed baroafferent fibers which were selectively stimulated. Outcome measures included change in systolic BP (SBP), diastolic BP (DBP), and HR during and after stimulation. Results: 14 subjects met eligibility criteria. In 13, following correct contact identification, stimulation caused a 23±20mmHg (mean±SD) maximum drop in SBP with associated drops in DPB (11±9mmHg), and HR (10±9bpm). All subjects recovered immediately following stimulation withdrawal. All drops were significant (p&lt;0.001, t-test). In subjects with baseline SBP &gt;120mmHg (n=8), maximum SBP drop was 30±23mmHg, while subjects with baseline SBP &lt;120mmHg (n=5) exhibited a maximum SBP drop of 11±3mmHg. There was evidence of a positive dose (current) response relationship. Conclusions: Using a novel surgical approach and electrode, CSN stimulation in anesthetized human subjects caused a marked drop in BP/HR followed by rapid recovery with stimulation withdrawal. There was evidence of dose dependency.

Methylxanthine Derivatives in the Treatment of Sinus Node Dysfunction: A Systematic Review.

While the chronotropic effects of theophylline and aminophylline are well-known, their clinical application in the treatment of sinus node dysfunction has not been established in a review. The purpose of this systematic review is to evaluate the efficacy and safety of methylxanthines in the treatment of bradyarrhythmias associated with sinus node dysfunction. A systematic review was conducted in accordance with PRISMA guidelines on Embase, PubMed, MEDLINE, Cochrane Central, Web of Science, SciELO, Korean Citation Index, Global Index Medicus, and CINAHL through June 2023. A total of 607 studies were identified through the literature search. After applying the inclusion and exclusion criteria, 14 studies were included in this review. The causes of bradyarrhythmias involving the sinoatrial node included acute cervical spinal cord injury, coronavirus disease of 2019, carotid sinus syncope, chronotropic incompetence, heart transplant, and chronic sinus node dysfunction. Theophylline and aminophylline were shown to be effective for increasing heart rate and reducing the reoccurrence of bradyarrhythmias. The data on symptom resolution was conflicting. While many case studies reported a resolution of symptoms, a randomized controlled trial reported no significant difference in symptom scores between the control, theophylline, and pacemaker groups in the treatment of sick sinus syndrome. The incidence of adverse effects was low across all study designs. The data suggests methylxanthines may be useful as an alternative or bridge to nonpharmacologic pacing; however, dosing has yet to be established for various indications. Overall, methylxanthines proved safe and effective as a pharmacologic therapy for bradyarrhythmic manifestations of sinus node dysfunction.

Abstract 115: Carotid Intraluminal Thrombus Obscuring Underlying Carotid Web: Case Report

Introduction Carotid webs (CaW) have been increasingly recognized as a unique cause of recurrent ischemic strokes.1 They are defined as thin, intraluminal, shelf‐like lesions along the posterior aspect of the carotid bulb.1,2 Despite more awareness and ongoing studies into their pathogenesis, diagnosis, and management,3 they are still overlooked in clinical practice as a primary carotid ischemic etiology. Our case describes a patient with right extracranial internal carotid artery (ICA) thrombus secondary to later‐diagnosed CaW on close follow‐up imaging. Methods We report a 55‐year‐old African American man with history of hypertension, type 2 diabetes mellitus and hyperlipidemia presented with acute onset slurred speech and left facial droop (FP). His last known well was 24 hours prior to presentation, and NIHSS upon arrival was 3 (FP 2, dysarthria 1). CT angiography (CTA) of the head and neck demonstrated a nearly occlusive thrombus of the distal right M2 segment MCA as well as non‐hemodynamic stenosis of the proximal right ICA with possible underlying sidewall filling defect‐appearing lesion concerning for a posterior wall thrombus without underlying atherosclerosis at the bulb or otherwise. The patient was admitted to the neurovascular intensive care unit and started on aspirin and high‐risk heparin drip. His MRI Brain demonstrated multiple acute/subacute right MCA territory strokes, predominately in the right posterior insula, right frontal lobe, and right posterior corona radiata. His stroke workup was otherwise unrevealing, and he was discharged on apixaban 5mg BID. Results Close surveillance follow‐up imaging with CTA head and neck was planned and obtained one month later, which demonstrated resolution of the filling defect that was obscuring the currently visualized underlying right CaW pocket (Figure‐1). The prevalence of CaWs has been reported to be between 1.2% and 2.5% of patients with acute ischemic stroke. CaWs are most frequently seen in younger, female patients, and patients with these lesions are at increased risk of recurrent stroke.4,5 Determining the optimal management for these lesions remains essential, but the available data thus far have not been conclusive. Most patients are treated with antiplatelet therapy, but some elect to treat with anticoagulation due to the focal hemostasis caused by CaWs.6 However, multiple studies have suggested that medical management alone is likely not sufficient in reducing the recurrent stroke risk caused by CaWs.5,7 Neuro‐interventional procedures including carotid artery stenting have been reported as secondary prevention strategies in patients with recurrent strokes.5,7,8 Although data regarding the rate of recurrence of strokes secondary to these lesions remains unclear, the current data does suggest benefit and safety in pursuing carotid stenting to prevent recurrent strokes.5‐8 Conclusion In young patients with proximal ICA thrombosis without underlying atherosclerosis or other conventional stroke risk factors, CaW should be considered among other differentials including hypercoagulable status. Following acute medical management, short‐term surveillance imaging is essential to confirm or rule out the diagnosis. In our case, the patient’s proximal ICA thrombus resolved after short course of anticoagulation and was determined to be secondary to the obscured underlying CaW.

Abstract 213: Successful Mechanical Thrombectomy in Acute Stroke With Pre‐interventional Thrombolysis‐Induced Intracerebral Hemorrhage: Case Report

Introduction Intravenous thrombolytics (IVT) and mechanical thrombectomy (MT) have become the standards of care for treating patients with large vessel occlusion (LVO) acute ischemic strokes (AIS) [1‐4}. Intracerebral hemorrhage (ICH) is a main complication of IVT, with prevalence reported around 3.2% in a large multicentered meta‐analysis [2,6]. However, limited data remains about the safety and efficacy for patients to undergo MT with IVT associated pre‐interventional ICH as no randomized control trials or standard of care guidelines are available [2,4,5,7]. Methods NA Results 56‐yo male with history of alcohol abuse presented via EMS as a stroke alert with acute onset right hemiplegia, global aphasia, right facial droop, and leftward gaze preference two hours prior to arrival. RACE 10+ with NIHSS 24. No known history antiplatelet or anticoagulation use. Computerized Tomography (CT) Brain scan showed left middle cerebral artery (MCA) hyperdense sign with left insular cortical ribboning. CT angiography (CTA) showed near occlusive stenosis of the left carotid bulb with an acute thrombus within Supraclinoid Internal Carotid Artery (ICA) extending into the Left MCA and origin of Left Anterior Cerebral Artery (ACA). Patient was emergently administered IV‐tissue Plasminogen Activator (IV‐tPA) and taken for endovascular thrombectomy. During initial angiogram, after crossing the stenotic cervical bulb, the left Supraclinoid ICA and MCA occlusions were visualized. There was longitudinal partially occlusive thrombus extending from the M1 into the M2 divisions. No opacification of the inferior M2 branch was visualized, with perfusion deficit over the temporal, parietal and frontal regions. Additionally, extravasation of contrast was seen within the left basal ganglia region, concerning for hemorrhagic transformation from IV‐tPA. Reversal of IV‐tPA was initiated, and patient was given cryoprecipitate, platelets, and tranexamic acid. Decision to undergo MT was made secondary to severity of debilitating neurologic symptoms, age, and large perfusion deficit observed. He underwent single pass complete recanalization, TICI 2C using Stent retriever and aspiration. Left ICA stenting was not completed secondary to hemorrhagic transformation. Repeat CT Brain confirmed moderate left frontal lobe hemorrhage with vasogenic edema and 3mm left‐to‐right midline shift. No neurosurgical intervention required. Magnetic resonance imaging (MRI) Brain showed left cerebral hematoma with mass effect, acute infarct within left caudate nucleus, and minimal posterior cortical restricted diffusion without hemorrhagic conversion. Patient was monitored for 1 week with serial brain imaging. Patient was discharged on Aspirin 81 mg daily to inpatient rehabilitation with NIHSS 21, mRS 4 (0 prestroke). Today, in rehab he ambulates with walker with moderate expressive aphasia and right upper extremity weakness. Plan to follow‐up 2‐month post‐hospitalization for left ICA stenting. Conclusion While pre‐interventional IVT‐associated ICH in AIS with LVO are rare, few cases have been shown to have positive neurological outcomes [2,5,7]. We demonstrate a unique case of early identification of reperfusion hemorrhage on fluoroscopy with prompt reversal initiated. The decision to continue with MT based on downstream occlusion of basal ganglia hemorrhage not at further risk of expansion from reperfusion. The patient did well on follow‐up imaging despite the hemorrhage. Further randomized control clinical trials are required to establish best care guidelines, safety, and efficacy.

Camouflaged cardiac alert: Correlation of breast arterial calcification with carotid intima media thickness for evaluation of cardiac risk

Objectives: To determine the association between breast arterial calcification (BAC) and carotid intima-media thickness (C-IMT) and, in turn, predict the risk of cardiovascular events. To independently access its relationship with other co-morbidities like diabetes mellitus (DM), hypertension (HTN), and menopause with BAC. Material and Methods: A total of 540 patients (270 with BAC and 270 without BAC) in the age group of 40–60 years who underwent mammograms at our institution between April 2021 to October 2021 were included in the study. In addition, an ultrasound was performed to evaluate the intima-media thickness in bilateral common carotid arteries 1 cm proximal to the carotid bulb. The mean C-IMT between the two groups (patients with and without BAC) was compared to understand the relationship between C-IMT and BAC. The independent relationship of BAC was also evaluated with the risk of co-morbidities like DM, HTN, and menopause. Results: The median C-IMT was higher in the group with BAC (0.85 mm, interquartile range (IQR) = 0.2) than in the group without BAC (0.6 mm, IQR = 0.10), which is statistically highly significant with p &lt; 0.001. Further analysis among subgroups of age and DM also revealed IMT to be significantly higher in the group with BAC (0.85 mm, IQR = 0.20) compared to those without BAC (0.6 mm, IQR = 0.15) (p &lt; 0.001). The median age in patients with BAC was significantly higher (57 years, IQR = 10 years) than those without BAC (48 years, IQR = 11.8 years) (p &lt; 0.001). In the group with BAC, a higher proportion of patients were diabetics, hypertensives and had attained menopause, then in the subgroup without BAC. Conclusion: Patients with BAC had higher C-IMT, which in turn correlates with a higher risk of cardiovascular events. Hence, the presence of BAC can be used as a substitute marker for identifying patients with a higher risk of cardiovascular events and for ruling out co-morbidities such as DM and HTN.