Dyslipidemia Treatment and Cerebrovascular Disease: Evidence Regarding the Mechanism of Stroke

Dyslipidemia stands as a significant risk factor for stroke, on par with the impact of hypertension, diabetes, and smoking. While the role of dyslipidemia is firmly established in the context of coronary artery disease, its influence on strokes remains somewhat enigmatic. This complexity likely arises from the diverse mechanisms underpinning strokes, which encompass a heterogeneous spectrum (hemorrhagic and ischemic; large artery atherosclerosis, small vessel occlusion, cardioembolism, and etc.). The extent to which lipid-lowering treatments affect stroke outcomes may vary depending on the specific stroke subtype. For instance, in cases of large artery atherosclerosis (LAA), the optimal target level of low-density lipoprotein cholesterol (LDL-C) is relatively clear. However, when dealing with other stroke subtypes like small vessel occlusion or cardioembolism, the appropriate LDL-C target remains uncertain. Furthermore, reperfusion therapy has emerged as the foremost treatment for acute ischemic stroke. Nevertheless, the precise relationship between LDL-C levels and outcomes in patients undergoing reperfusion therapy remains shrouded in uncertainty. Consequently, we have undertaken an in-depth exploration of the existing evidence supporting the utilization of lipid-lowering medications such as statins, ezetimibe, and proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors. Our objective is to elucidate their role in secondary stroke prevention and the management of dyslipidemia across the various stroke subtypes.

Wall Shear Stress Associated with Stroke Occurrence and Mechanisms in Middle Cerebral Artery Atherosclerosis / 대한뇌졸중학회지

Background@#and Purpose Various mechanisms are involved in the etiology of stroke caused by atherosclerosis of the middle cerebral artery (MCA). Here, we compared differences in plaque nature and hemodynamic parameters according to stroke mechanism in patients with MCA atherosclerosis. @*Methods@#Consecutive patients with asymptomatic and symptomatic MCA atherosclerosis (≥50% stenosis) were enrolled. MCA plaque characteristics (location and plaque enhancement) and wall shear stress (WSS) were measured using high-resolution vessel wall and four-dimensional flow magnetic resonance imaging, respectively, at five points (initial, upstream, minimal lumen, downstream, and terminal). These parameters were compared between patients with asymptomatic and symptomatic MCA atherosclerosis with infarctions of different mechanisms (artery-to-artery embolism vs. local branch occlusion). @*Results@#In total, 110 patients (46 asymptomatic, 32 artery-to-artery embolisms, and 32 local branch occlusions) were investigated. Plaques were evenly distributed in the MCA of patients with asymptomatic MCA atherosclerosis, more commonly observed in the distal MCA of patients with artery-to-artery embolism, and in the middle MCA of patients with local branch occlusion. Maximum WSS and plaque enhancement were more prominent in the minimum lumen area of patients with asymptomatic MCA atherosclerosis or those with local branch occlusion, and were more prominent in the upstream area in those with artery-to-artery embolism. The elevated variability in the maximum WSS was related to stroke caused by artery-to-artery embolism. @*Conclusion@#Stroke caused by artery-to-artery embolism was related to plaque enhancement and the highest maximum WSS at the upstream point of the plaque, and was associated with elevated variability of maximum WSS.

An Acute Metabolic Encephalopathy, Lactic Acidosis and Stroke-like Episodes Syndrome Patients with Hyperperfusion Responsive to Steroid Treatment

Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) is a genetic disorder caused by mutation in mitochondrial DNA. Patients with stroke-like episodes show restrictive lesions in diffusion weighted image, whereas magnetic resonance angiography images show both vasodilation or vasoconstriction. Vasodilation may lead to hyperperfusion and cerebral edema, which may worsen clinical outcome. Here, we report a 25-year-old male patient diagnosed as MELAS, who presented with stroke-like episodes and seizures and showed cerebral edema with vasodilation which was normalized after steroid treatment.

Comparison of Dexmedetomidine and Remifentanil on Airway Reflex and Hemodynamic Changes during Recovery after Craniotomy

PURPOSE: During emergence from anesthesia for a craniotomy, maintenance of hemodynamic stability and prompt evaluation of neurological status is mandatory. The aim of this prospective, randomized, double-blind study was to compare the effects of dexmedetomidine and remifentanil on airway reflex and hemodynamic change in patients undergoing craniotomy. MATERIALS AND METHODS: Seventy-four patients undergoing clipping of unruptured cerebral aneurysm were recruited. In the dexmedetomidine group, patients were administered dexmedetomidine (0.5 µg/kg) for 5 minutes, while the patients of the remifentanil group were administered remifentanil with an effect site concentration of 1.5 ng/mL until endotracheal extubation. The incidence and severity of cough and hemodynamic variables were measured during the recovery period. Hemodynamic variables, respiration rate, and sedation scale were measured after extubation and in the post-anesthetic care unit (PACU). RESULTS: The incidence of grade 2 and 3 cough at the point of extubation was 62.5% in the dexmedetomidine group and 53.1% in the remifentanil group (p=0.39). Mean arterial pressure (p=0.01) at admission to the PACU and heart rate (p=0.04 and 0.01, respectively) at admission and at 10 minutes in the PACU were significantly lower in the dexmedetomidine group. Respiration rate was significantly lower in the remifentanil group at 2 minutes (p<0.01) and 5 minutes (p<0.01) after extubation. CONCLUSION: We concluded that a single bolus of dexmedetomidine (0.5 µg/kg) and remifentanil infusion have equal effectiveness in attenuating coughing and hemodynamic changes in patients undergoing cerebral aneurysm clipping; however, dexmedetomidine leads to better preservation of respiration.

Efficacy of intraoperative dexmedetomidine infusion on visualization of the surgical field in endoscopic sinus surgery / 대한마취과학회지

BACKGROUND: In endoscopic sinus surgery, visualization of the surgical field is a major concern, as surgical bleeding is the cause of many complications. The purpose of this study was to compare the effects of dexmedetomidine and remifentanil on the visualization of the surgical field in endoscopic sinus surgery. METHODS: Forty-three patients were prospectively enrolled and randomly allocated to the dexmedetomidine or remifentanil group and general anesthesia was induced and maintained using a propofol target-controlled infusion. In the dexmedetomidine group, dexmedetomidine was loaded for 5 min and a continuous infusion was administered. In the remifentanil group, a remifentanil target-controlled infusion was used. After completion of the operation, the satisfaction with the visualization of the surgical field was assessed on a numeric rating scale, from 0 (= worst) to 10 (= best). The mean blood pressure, heart rate, recovery profiles, and postoperative pain score were recorded. RESULTS: Satisfaction score for visualization by numeric rating scale was not significantly different between the two groups (P = 0.95). There were no differences in the mean blood pressure and heart rate. The extubation time was significantly shorter in the dexmedetomidine group (8.4 +/- 1.8 min) than in the remifentanil group (11.9 +/- 5.4 min) (P = 0.04). Except for the extubation time, the recovery profiles of the two groups were comparable. CONCLUSIONS: Continuous infusions of dexmedetomidine provide a similar visualization of the surgical field and hemodynamic stability as remifentanil target-controlled infusions in patients undergoing endoscopic sinus surgery.

Comparison of the antiemetic effect of ramosetron with ondansetron in patients undergoing microvascular decompression with retromastoid craniotomy: a preliminary report / 대한마취과학회지

BACKGROUND: Microvascular decompression with retromastoid craniotomy carries an especially high risk of postoperative nausea and vomiting. In this study, we compare the antiemetic efficacy of ramosetron and ondansetron in patients undergoing microvascular decompression with retromastoid craniotomy. METHODS: Using balanced anesthesia with sevoflurane and remifentanil infusion, ondansetron 8 mg (group O, n = 31) or ramosetron 0.3 mg (group R, n = 31) was administered at the dural closure. The incidence and severity of postoperative nausea and vomiting, required rescue medications and the incidence of side effects were measured at post-anesthetic care unit, 6, 24 and 48 hours postoperatively. Independent t-tests and the chi-square test or Fisher's exact test were used for statistical analyses. RESULTS: There were no differences in the demographic data between groups, except for a slightly longer anesthetic duration of group R (P = 0.01). The overall postoperative 48 hour incidences of nausea and vomiting were 93.6 and 61.3% (group O), and 87.1 and 51.6% (group R), respectively. Patients in group R showed a less severe degree of nausea (P = 0.02) and a lower incidence of dizziness (P = 0.04) between 6 and 24 hours. CONCLUSIONS: The preventive efficacy of ramosetron when used for postoperative nausea and vomiting was similar to that of ondansetron up to 48 hours after surgery in patients undergoing microvascular decompression with retromastoid craniotomy. A larger randomized controlled trial is needed to confirm our findings.

Remote cerebellar hemorrhage after unruptured cerebral aneurysm surgery: two cases report / 대한마취과학회지

Remote cerebellar hemorrhage (RCH) occurring distant to the site of original surgery, such as supratentorial or spinal surgery, is rare but potentially fatal. Because the pathophysiology of RCH is thought to be excessive cerebrospinal fluid drainage during the perioperative periods, its diagnosis usually depends on the occurrence of unexpected neurologic disturbances and/or postoperative brain computerized tomography imaging. Because of its rarity, RCH-associated neurologic disturbances such as delayed awakening or nausea and vomiting may often be misdiagnosed as the effects of residual anesthetics or the effect of postoperative analgesic agents unless radiologic images are taken. Treatment for RCH ranges from conservative treatment to decompressive craniectomy, with prognoses ranging from complete resolution to fatality. Here, we report two cases of RCH after surgical clipping of an unruptured cerebral aneurysm of the anterior communicating artery and review anesthetic considerations.

Efficacy of dexamethasone added to ramosetron for preventing postoperative nausea and vomiting in highly susceptible patients following spine surgery / 대한마취과학회지

BACKGROUND: Opioid-based patient controlled analgesia (PCA) provides adequate pain control following spinal surgeries at the expense of increased risk of postoperative nausea and vomiting (PONV). We evaluated the efficacy of dexamethasone added to ramosetron, which is a newly developed five-hydroxytryptamine receptor 3 antagonist with a higher receptor affinity and longer action duration compared to its congeners, on preventing PONV in highly susceptible patients receiving opioid-based IV PCA after spinal surgery. METHODS: One hundred nonsmoking female patients undergoing spinal surgery were randomly allocated to either a ramosetron group (group R) or a ramosetron plus dexamethasone group (group RD)., Normal saline (1 ml) or 5 mg of dexamethasone was injected before anesthetic induction, while at the end of the surgery, ramosetron (0.3 mg) was administered to all patients and fentanyl-based IV PCA was continued for 48 hrs. The incidence and severity of PONV, pain score and the amount of rescue antiemetics were assessed for 48 hours after surgery. RESULTS: The number of patients with moderate to severe nausea (20 vs. 10, P = 0.029), and overall incidence of vomiting (13 vs. 5, P = 0.037) were significantly lower in the group RD than in the group R, respectively. Rescue antiemetic was used less in the RD group without significance. CONCLUSIONS: Combination of ramosetron and dexamethasone significantly reduced the incidence of moderate to severe nausea and vomiting compared to ramosetron alone in highly susceptible patients receiving opioid-based IV PCA after surgery.

Posterior reversible encephalopathy syndrome in an untreated hypertensive patient after spinal surgery under general anesthesia: A case report / 대한마취과학회지

Posterior reversible encephalopathy syndrome (PRES) is an unfamiliar term to anesthesiologists, and this is characterized by neurologic symptoms that include mental change, headache, seizure and visual disturbance and also abnormal neuroimaging finding. A 71-year-old female patient was operated on for posterior decompression and total laminectomy under general anesthesia for the spinal stenosis. After the operation, she developed generalized tonic-clonic seizure and a stuporous mentality in the recovery room. The magnetic resonance imaging (MRI) revealed swelling and increased signal intensity at the deep gray nuclei, cerebral cortex and cerebellum. After one week, she returned to an alert mentality and then she was diagnosed with PRES. She was discharged without any neurologic deficit on postoperative day 20. This report describes our experience with PRES after spinal surgery was performed under general anesthesia on a suspected untreated hypertensive patient.

Use of dexmedetomidine for awake crainiotomy / 대한마취과학회지

No abstract available.

Ejaculatory Failure after Unilateral Neurolytic Celiac Plexus Block

Abdominal pain associated with chronic pancreatitis is often difficult to control with analgesics and can be severely debilitating with significant impairment of quality of life. In these patients, neurolytic celiac plexus block (NCPB) is an effective treatment option with a low complication rate. However, there is a risk of ejaculatory failure after NCPB, which may be a problem in patients with a long life expectancy. We report a case of ejaculatory failure after unilateral NCPB in a patient with chronic pancreatitis.