Perioperative stroke. Part I: General surgery, carotid artery disease, and carotid endarterectomy

STA-MCA Bypass as a "Bridge" to Pituitary Surgery in a Patient with an Adenoma Occluding the Internal Carotid Artery: Case Report and Review of the Literature

Occlusion of the intracranial internal carotid artery (ICA) by a pituitary adenoma with resulting cerebral ischemia is a very rare but devastating occurrence. The authors present a case in which a condition of symptomatic ICA occlusion due to a giant pituitary adenoma was successfully treated using a preliminary extraintracranial bypass as a “bridge” to the tumor removal. A 52-year-old patient presented with a minor stroke followed by pressure-dependent transient ischemic attacks consistent with a condition of hypoperfusion. MR imaging and a digital subtraction angiography revealed a pituitary adenoma occluding the ICA on the right side. He underwent a superficial temporal artery to middle cerebral artery (STA-MCA) bypass with the aim of revascularizing the ischemic hemisphere and reducing the risk of perioperative stroke or stroke evolution. The patient was subsequently operated on to remove the adenoma through a transsphenoidal approach. The postoperative course was uneventful and the patient has suffered no further ischemic events. When there are no emergency indications to decompress the optical pathways but the patient is at risk of impending stroke because of ICA occlusion, a two-step strategy consisting of a bypass and subsequent removal of the pituitary adenoma may be a valuable option.

Hypotensive anesthesia versus normotensive anesthesia during major maxillofacial surgery: a review of the literature

Steady blood pressure within normal limits during surgery is one of the markers of the ideal and skillful anesthesia. Yet, reduced blood pressure is advantageous in some settings because it can contribute to a reduction in overall blood loss and improve the surgical field conditions. Controlled hypotension during anesthesia or hypotensive anesthesia is often used in major maxillofacial operations. Since hypotensive anesthesia carries the risk of hypoperfusion to important organs and tissues, mainly the brain, heart, and kidneys, it cannot be applied safely in all patients. In this paper we review the medical literature regarding hypotensive anesthesia during major maxillofacial surgery, the means to achieve it, and the risks and benefits of this technique, in comparison to normotensive anesthesia.

[Epidemiology of cerebral perioperative vascular accidents]

OBJECTIVES

Stroke is a well-described postoperative complication, after carotid and cardiac surgery. On the contrary, few studies are available concerning postoperative stroke in general non-cardiac non-carotid surgery. The high morbid-mortality of stroke justifies an extended analysis of recent literature.

ARTICLE TYPE

Systematic review.

DATA SOURCES

Firstly, Medline and Ovid databases using combination of stroke, cardiac surgery, carotid surgery, general non-cardiac non-carotid surgery as keywords; secondly, national and European epidemiologic databases; thirdly, expert and French health agency recommendations; lastly, reference book chapters.

RESULTS

In cardiac surgery, with an incidence varying from 1.2 to 10% according to procedure complexity, stroke occurs peroperatively in 50% of cases and during the first 48 postoperative hours for the others. The incidence of stroke after carotid surgery is 1 to 20% according to the technique used as well as operator skills. Postoperative stroke is a rare (0.15% as mean, extremes around 0.02 to 1%) complication in general surgery, it occurs generally after the 24-48th postoperative hours, exceptional peroperatively, and 40% of them occurring in the first postoperative week. It concerned mainly aged patient in high-risk surgeries (hip fracture, vascular surgery). Postoperative stroke was associated to an increase in perioperative mortality in comparison to non-postoperative stroke operated patients.

CONCLUSION

Postoperative stroke is a quality marker of the surgical teams' skill and has specific onset time and induces an increase of postoperative mortality.

Comparison of clonidine and epinephrine in lidocaine anaesthesia for lower third molar surgery

The admixture of clonidine or epinephrine to lidocaine for inferior alveolar nerve block was studied with regard to onset, duration, intensity of anaesthesia, postoperative analgesia, systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR), ST segment depression > or =1 mm and cardiac arrhythmias. Forty healthy patients (ASA I) received 2 ml 2% lidocaine with clonidine (15 microg/ml; n = 20) or epinephrine (12.5 microg/ml; n = 20) in a double-blind fashion for lower third molar surgery. Duration and intensity were not different between groups, while onset was significantly different by subjective evaluation. The need for postoperative pain medication was significantly lower in the clonidine group. There was a significant decrease in SBP and MAP in both groups 35 min after administration of anaesthesia compared with basal values, while DBP was significantly lower only in the clonidine group. There was no significant difference in SBP, DBP and MAP between groups. HR was significantly increased in the epinephrine group 5 min after administration of anaesthesia and during surgery compared with the clonidine group and with basal values. The presented data suggest that clonidine could be a useful and safe alternative to epinephrine for intraoral block anaesthesia.

Prolonged retraction on the normal common carotid artery induced lethal stroke after cervical spine surgery

STUDY DESIGN

Case report.

OBJECTIVE

To report a previously undescribed complication of prolonged retraction on the normal common carotid artery after anterior cervical spine surgery.

SUMMARY OF BACKGROUND DATA

Previous study showed that prolonged retraction could decrease the blood flow of the common carotid artery during anterior cervical spine surgery. A case report revealed that prolonged retraction could induce the formation of thrombosis in the atherosclerotic common carotid artery.

METHODS

Notes review. Computed tomography of the brain was performed on the first and the fourth postoperative day. Carotid Doppler ultrasound and transcranial Doppler ultrasound were performed to evaluate the left common carotid artery and the left intracranial cerebral arteries.

RESULTS

After lengthy anterior cervical spinal surgery, the patient did not regain his consciousness during the stay in the postoperative care unit. Large infarction of left cerebral hemisphere was revealed by computed tomography. The patient died on the seventh postoperative day of perioperative lethal stroke.

CONCLUSION

We suggest that prolonged retraction, even on the normal common carotid artery, could induce lethal stroke after anterior cervical spine surgery. We recommend that retractor should be placed carefully and cerebral perfusion should be maintained adequately.

Surgery in the patient with neurologic disease

Patients with neurologic disease who require surgery present distinct issues and challenges for the medical consultant. Although it is not possible to offer a unified approach to neurologic patients, the primary care consultant should understand the clinical issues that are common to these patients, and the individual considerations necessitated by the nature of the neurologic disorder and the clinical characteristics of the patient. The preoperative evaluation combines elements of literature evidence on risk assessment with a thorough understanding of the planned procedure and local practice patterns, and clinical judgment as to the estimated risk-benefit ratio. Perioperative management necessitates attention to many general principles of perioperative care, such as awareness of the potential for cardiopulmonary complications and the need for DVT prophylaxis. In addition, there are management issues for neurologic patients, such as blood pressure control and evaluation of hyponatremia, which may differ from other surgical patients. In these circumstances, the interaction of the neurologic condition with the medical condition and the implications of treatment on the underlying neurologic process also need to be considered.

Minimizing perioperative adverse events in the elderly

Elderly patients still have the highest postoperative mortality and morbidity rate in the adult surgical population. Preoperative clinical assessment to detect patients at high risk of postoperative events, and specific intraoperative and postoperative anaesthesia management are important to minimize postoperative adverse events in the elderly.

The effect of perioperative aspirin therapy in peripheral vascular surgery: a decision analysis

Patients who undergo infrainguinal revascularization surgery are at increased risk for perioperative thrombotic complications. Aspirin decreases thrombotic events in the nonoperative setting; however, aspirin is often discontinued to avoid perioperative hemorrhagic complications. We used a decision analysis to determine whether aspirin should be discontinued before infrainguinal revascularization surgery. Two strategies were compared: aspirin cessation 2 wk before surgery and aspirin continuation throughout the perioperative period. Clinical events examined included myocardial infarction, thrombotic cerebrovascular accident, hemorrhagic cerebrovascular accident, gastrointestinal hemorrhage, and incisional hemorrhagic complications. Event rates and effect of aspirin were obtained by using MEDLINE. The outcomes were perioperative mortality, life expectancy, and quality-adjusted life expectancy. According to the model, continued aspirin use decreased perioperative mortality rates from 2.78% to 2.05%. Continued aspirin use increased life expectancy from 14.83 to 14.89 yr and increased quality-adjusted life expectancy from 14.72 to 14.79 yr. Aspirin increased the number of hemorrhagic complications by 2.46%, primarily because of an increased incidence of non-life-threatening complications.

A review of comorbidities and spinal surgery

As the population ages, greater numbers of elderly patients will be considered for spinal surgery for spinal stenosis and complex primary and revision reconstructions. The age-related medical comorbidities impact not only on the decision to undertake a procedure but also impact the magnitude of the procedure. The surgeon must understand aging and medical comorbidities to facilitate preoperative decision-making and postoperative care. A review of the more common age-related pathophysiologic changes to the cardiovascular, pulmonary, and central nervous systems is undertaken. General recommendations for perioperative treatment are made relative to published series regarding the impact of age and medical comorbidities on short- and long-term outcomes.

Stroke following appendectomy under general anesthesia in a patient with basilar impression

We report a boy who developed a vertebral stroke immediately after an appendectomy. Basilar impression was diagnosed eight years after this event when skull roentgenograms revealed basilar impression with high standing tip of the odontoid. We speculate that muscle relaxation and cervical hyperextension during intubation in the presence of basilar impression resulted in vertebral artery dissection and stroke. We suggest that patients with vertebral stroke and no obvious risk factors should be evaluated for the presence of malformations of the craniovertebral junction to be able to take precautions against excessive neck movement during intubation.

Risk factors for post-carotid endarterectomy hematoma formation

PURPOSE

To identify risk factors for post-carotid endarterectomy (CEA) hematoma formation and establish the incidence of this complication at The Ottawa Hospital - Civic Campus (TOH-CC).

METHODS

A chart review of all patients who underwent CEA at TOH-CC from January 1, 1996 to December 31, 1997 was completed. Identified cases of post-CEA wound hematoma were entered into a case-control study using age and sex-matched controls from within the cohort. These matched pairs were assessed for 31 potential risk factors including demographic details, co-existing medical conditions, preoperative medications, intraoperative management, and postoperative parameters. Risk factors associated with post-CEA hematoma with P<0.05 were entered into a backward step-wise logistic regression model for multivariate analysis.

RESULTS

Charts from 249 patients were reviewed and 29 cases of post-carotid endarterectomy hematoma were identified (12% incidence). Six of the initial 31 potential risk factors emerged as univariate predictors of post-CEA hematoma formation (P<0.05): general anesthesia, carotid shunt placement, intraoperative hypotension, non-reversal of heparin, neurosurgery service, and preoperative aspirin use. Following logistic regression only non-reversal of heparin, intraoperative hypotension, and carotid shunt placement were identified as multivariate predictors of post-CEA hematoma formation. More time was spent in critical care settings (ICU/PACU) (P<0.01) and there was increased perioperative mortality (P = 0.04) within the hematoma group.

CONCLUSIONS

Post-CEA hematoma formation is associated with increased morbidity and mortality. Non-reversal of heparin, intraoperative hypotension, and carotid shunt placement are multi-variate predictors of post-CEA hematoma formation.

Preoperative cardiac preparation

Preoperative preparation of the cardiac patient is based on matching the cardiac reserve to the blood flow demands imposed by surgical stress and the underlying disease state. Evaluation must include functional assessment of any coronary artery disease or other organic cardiac disease that may place myocardial tissue at risk of ischemia as demand for cardiac output increases. Monitoring should be individualized based on anticipated problems and the risk assessment of the patient. Preoperative therapy should include maneuvers that reduce congestive heart failure, optimize volume status, and provide adequate cardiac output to deliver oxygen sufficient to meet or exceed demand. Underlying electrical and metabolic abnormalities should be corrected and controlled in the perioperative period. Long-term therapy should be evaluated and modified in the context of the anesthetic and surgical plan. Preventive interventions such as fluid loading and low-dose dopamine should be considered prior to surgery.

Cerebral infarct following central venous cannulation

Inadvertent carotid artery puncture is a well-known complication of internal jugular vein cannulation. A case of cerebral infarct subsequent to carotid artery puncture during internal jugular vein cannulation is reported.

Lumbosacral plexopathy from iliopsoas haematoma after combined general-epidural anaesthesia for abdominal aneurysmectomy

PURPOSE

To report a case of iliopsoas haematoma after resection of an abdominal aortic aneurysm which resulted in a lumbosacral plexopathy.

CLINICAL FEATURES

An 81-yr-old man presented with an abdominal aortic aneurysm for aneurysmectomy and tube grafting. An epidural catheter was placed at the L1-2 spinal level and combined epidural-general anaesthesia was provided for surgery. The surgery was complex and a suprarenal clamp was necessary to obtain proximal control. A continuous infusion of demerol through the epidural catheter was prescribed for postoperative analgesia. On the first postoperative day, examination revealed a paretic, pulseless right leg and he was returned to the operating room for femoral-femoral bypass. By the following day, the motor and sensory impairment had progressed to complete paralysis with loss of all deep tendon reflexes and absent sensation below L1, despite palpable pulses in the leg. A CT of the abdomen demonstrated a right iliopsoas haematoma. There was no evidence of either disc herniation or an epidural haematoma. A diagnosis of lumbosacral plexopathy secondary to a iliopsoas haematoma was made.

CONCLUSION

Iliopsoas haematoma is a rare cause of postoperative neurological deficit following aortic vascular surgery. The haematoma results in compression of the lumbosacral neural elements and typically presents as a femoral neuropathy. The diagnosis is clinical and can be readily validated with computed tomography.

The effects of carotid sinus nerve blockade on hemodynamic stability after carotid endarterectomy

OBJECTIVE

To determine whether intraoperative administration of bupivacaine reduces the incidence of hypotension after carotid endarterectomy (CEA).

DESIGN

Prospective, double-blinded, randomized controlled trial.

SETTING

A single-institute, tertiary-care medical center.

PARTICIPANTS

Patients (n = 135) who were referred for CEA without prior ipsilateral CEA, diabetes mellitus, or allergies to local anesthetics.

INTERVENTIONS

2 mL of 0.25% bupivacaine or 2 mL NaCl (control) injected by the surgeon at the carotid sinus immediately after CEA.

MEASUREMENTS AND MAIN RESULTS

Blood pressure and heart rate were measured before induction, before carotid reperfusion, 2 minutes after reperfusion, before carotid sinus injection, and every 15 minutes thereafter for 2 hours. Anesthesia was induced and maintained with fentanyl, pancuronium, and 0.5% to 1% enflurane. Hypertension was defined as a systolic blood pressure 30% above baseline or greater than 180 mmHg. Hypotension was defined as a systolic blood pressure 30% below baseline or less than 100 mmHg. Postoperative incidences of hypertension, hypotension, and the associated use of corrective medications were compared in both groups using the chi-squared test to determine statistical significance. Patients in the bupivacaine group (n = 61) had a similar incidence of postoperative hypotension as controls (n = 74) but a higher incidence of hypertension (40% v 24%; p = 0.043). The bupivacaine group required vasodilators more often (33% v 18%; p = 0.04). Baseline hypertension and preoperative use of beta-blockers also were predictive of postoperative hypertension.

CONCLUSIONS

Carotid sinus area infiltration with bupivacaine after CEA does not reduce the incidence of postoperative hypotension but significantly increases the incidence of postoperative hypertension. Thus, its routine use cannot be recommended in carotid endarterectomy.

A comparison of postoperative thrombotic potential following abdominal aortic surgery, carotid endarterectomy, and femoro-popliteal bypass

Postoperative changes in procoagulant, anticoagulant, and antifibrinolytic factors were compared in patients undergoing abdominal aortic surgery, carotid endarterectomy, and femoro-popliteal bypass. There were increases in plasma fibrinogen (P < 0.01) and factor VIII coagulant (P < 0.01) levels following all three procedures. There were decreases in antithrombin III (P < 0.01) and protein C (P < 0.01), and increases in thrombin-antithrombin complex levels (P < 0.01) in the abdominal aortic group only. There were no significant changes in type 1 plasminogen activator inhibitor levels following any of the procedures. The results indicate that all three procedures are associated with an increased potential for thrombosis due to increases in procoagulant factors. However, patients undergoing abdominal aortic surgery are particularly at risk due to concurrent decreases in natural anticoagulant factors. Specific antithrombotic therapy should be considered for all patients undergoing vascular surgery, but particularly for those undergoing major procedures such as abdominal aortic surgery.

The role of neuromonitoring in cardiovascular surgery

This review describes the techniques currently used for quantitative neurophysiologic measurement during cardiac surgery and their potential impact on clinical outcome. Electroencephalography (EEG) characterizes cerebrocortical neuronal electrical activity and was part of some of the earliest cardiopulmonary bypass procedures, yet today it is not widespread use. Each of the common misunderstandings regarding a supposed limitation of this technology is explained. Its major genuine shortcoming, a lack of selectivity, may now be overcome with the combined use of additional monitoring modalities. The influence of intracranial hemodynamics on observed EEG changes may be determined continuously and noninvasively with transcranial Doppler (TCD) ultrasound. TCD provides an indication of sudden change in either blood flow or vascular resistance as well as the detection of emboli. In addition, the metabolic status of cortical neurons can be monitored by regional cerebral venous oxygen saturation (rCVOS) using noninvasive transcranial near-infrared spectroscopy. The % rCVOS tends to remain remarkably stable over a wide range of temperatures, perfusion pressures, and anesthetic states. Marked change in either direction signifies a serious imbalance between oxygen delivery and consumption. Measurement of rCVOS does not require blood flow, pulsatile or otherwise, so that it offers the only means of monitoring during circulatory arrest. By characterizing the dynamic interplay among cerebral hemodynamics, metabolism, and electrogenesis, these technologies permit the rapid detection and correction of potentially hazardous conditions.

Unexpected neurological deficits following recovery from anaesthesia

Two cases of neurological dysfunction are presented. Neurological deficits after recovery from anaesthesia are unusual in young women perioperatively. In the first case, a 39-yr-old woman presented at 36-wk gestation with antepartum haemorrhage and in labour. Pregnancy had been complicated by pre-eclampsia and she underwent emergency Caesarean section under general anaesthesia without complication. The trachea was extubated when she was awake but almost immediately she became hypertensive, obtunded and reintubation was required. Her pupils became fixed and dilated but the Computerised Axial Tomogram (CT) was normal. A coagulopathy was evident. She made a full neurological recovery within 24 hr. On the same day, a previously healthy 41-yr-old woman who had undergone uneventful surgery for uterine prolapse 24 hr previously developed headache, nausea and over the next four hours signs of progressive brainstem ischaemia. The CT scan showed oedema of the mid- and hindbrain. Brainstem death was confirmed 12 hr later and the post-mortem revealed acute dissection of the vertebral artery secondary to cystic medial necrosis. Such dramatic neurological sequelae are rare but the importance of identifying "at risk" groups is underlined as is early recognition of neurological injury postoperatively.

Combined use of aspirin and heparin inhibits in vivo acute carotid thrombosis

BACKGROUND AND PURPOSE

Carotid atherosclerotic thrombosis is an important cause of ischemic stroke in Western countries. The therapeutic efficacy of either aspirin or heparin alone in this setting is still controversial. Recently we developed a simple model, the "clamp" method, to induce acute carotid mural thrombosis in vivo in guinea pigs. In this study, we used this model to evaluate the antithrombotic effects of aspirin, heparin, and their combination.

METHODS

Sixty-four male guinea pigs were divided equally into control, aspirin, heparin, and combined groups. Physiological saline, aspirin (5 mg/kg body wt), heparin (200 units/kg body wt), or a combination of aspirin and heparin, respectively, was injected via the jugular vein before the use of the clamp method. Thirty minutes after the injection of saline or drug(s), Péan's forceps was used to clamp the carotid artery at a tangent angle for 3 minutes. One hour later, the carotid artery was resected and prepared for observation under a scanning electron microscope or light microscope to evaluate the degree of mural thrombosis.

RESULTS

The results showed that the combination of aspirin and heparin had an excellent effect in inhibiting in vivo acute carotid thrombosis (p < 0.001) and was significantly better than the effect of aspirin alone (p < 0.01) or heparin alone (p < 0.01).

CONCLUSIONS

Our study clearly demonstrated that the combined use of aspirin and heparin produced a much better antithrombotic effect than either agent alone at sites of carotid endothelial injury when given before the injury. This combined regimen may be useful clinically in acute carotid thrombosis secondary to carotid diseases or carotid endarterectomy.