Is Mechanical Embolectomy Performed in Nonanesthetized Patients Effective?

Discussion

The use of general anesthesia in endovascular procedures of patients with AIS is highly variable between interventionalists and institutions. Additionally, many of the current registries and previous trials do not have guidelines for the use of general anesthesia during endovascular treatment.^2,3 In our institution, the lack of general anesthesia does not adversely affect patient outcome or procedural complications; in fact, our results are compatible with those reported in previous trials and in registry data.

For example, in Prolyse in Acute Cerebral Thromboembolism II, a prospective study to determine the clinical efficacy and safety of intra-arterial recombinant prourokinase in patients with acute stroke of <6 hours' duration caused by MCA occlusion, a 66% recanalization rate, 40% good outcome rate, and 25% mortality rate were reported.¹ In the Multi MERCI registry trial, a trial of thrombectomy in patients with large-vessel stroke treated within 8 hours of symptom onset, a 69.5% revascularization rate, 5.5% procedural complication rate, 36% good outcome rate, and 34% mortality rate were reported.² In the Penumbra Pivotal Stroke trial, an examination of the safety and effectiveness of the Penumbra System (Penumbra, Alameda, California) in the revascularization of patients presenting with AIS secondary to intracranial large-vessel occlusive disease, an 81.6% revascularization rate, 12.8% procedural event rate, 25% good outcome rate, and 33% mortality rate were reported.³ Our revascularization rate in nonanesthetized patients of 70% (by MERCI criteria), procedural complications of 4%, good outcome of 50%, and mortality rate of 29% are compatible with these other studies.

Many of the effects of both the induction and recovery from general anesthesia on the ischemic brain and the outcome of patients with acute stroke are unknown. Some inhaled anesthetics, such as isoflurane, can lead to increases in intracranial pressure, while others can induce changes in the cerebral autoregulatory response to cardiac output, which is already impaired in the patient with AIS.¹³ Furthermore, both the induction and recovery periods are often associated with severe variations in blood pressure and heart rate, which can further decrease cerebral perfusion.^14,15 In combination, these direct and indirect actions of anesthetic agents may have negative effects on the outcomes of patients with AIS.

Another disadvantage of general anesthesia in the patient with AIS is the time needed to induce anesthesia. When 1.9 million neurons are destroyed every minute, any delay is costly.¹⁶ In our institution, there was not a significant difference between patients under general anesthesia and nonanesthetized patients; however, this may vary across institutions. Additionally, general anesthesia eliminates the ability to interact with the patient during the procedure, which may add an additional safety factor during endovascular treatment.¹⁷ We were able to treat 86% of our patients with AIS with minimal or no conscious sedation, preserving our ability to gain useful information from the patient during our endovascular treatment. For example, because intracranial vessels are very sensitive to stretching, we could alter endovascular treatment techniques on the basis of the patient's pain level, to reduce the risk of vessel perforation and intracerebral hemorrhage. Additionally, we were able to constantly assess their neurologic status both during the procedure and in the immediate period following the procedure, the period of highest risk for vessel reocclusion. In the acutely worsening patient, this ability allowed us to quickly reassess arterial reocclusion or intracerebral hemorrhage and alter medical management, such as anticoagulation reversal and blood pressure control, immediately.

In the nonanesthetized patient with AIS, lack of cooperation during the procedure could be a major disadvantage, prolonging time to revascularization and leading to procedural complications. In our study, this was not the case, with no significant differences found in procedural times and with a lower percentage of procedural complications. This may be due to our use of a standard method of restraint placement, if needed, which helps significantly to decrease patient movement during endovascular treatment.

The major limitations of our study are retrospective analysis and nonrandomized enrollment. Also, our populations were quite small, and comparison groups were not equal because our patients who underwent general anesthesia were significantly older and had more severe strokes. Finally, many factors that affect clinical outcomes were not controlled for, such as patient comorbidities, difference in techniques among operators, patient collateral characteristics, and differences in medical management.