General anesthesia may worsen outcomes in endovascular stroke treatment

1. Patients undergoing general anesthesia for endovascular treatment of acute stroke had increased odds of death and respiratory complications, and decreased odds of recanalization and good functional outcome as compared to those undergoing conscious sedation.

Evidence Rating Level: 1 (Excellent)

Study Rundown: While recent trials have demonstrated the value of rapid intra-arterial therapy for large-vessel acute ischemic stroke in improving patient outcomes, the effect of many of the specific procedural and peri-procedural details remains largely unexamined. A major factor in any procedure is the method of anesthesia, with general anesthesia plus intubation often believed to improve safety and efficacy of the procedure despite an association with cerebral hypoperfusion. Conscious sedation is often preferred in cases regarding neurologic function given the ability to monitor neurologic status in real-time, and has been associated with superior hemodynamic stability. The current study sought to better assess the risk difference between these two methods of anesthesia during endovascular treatment of acute stroke through a systematic review and meta-analysis of nine studies from the current literature. Conscious sedation appeared to confer lower odds of death and respiratory complications and higher odds of superior functional outcomes and successful recanalization as compared to general anesthesia. However, the results were confounded by a pre-intervention difference in baseline stroke severity between the two groups, as those undergoing general anesthesia had higher average NIHSS scores, and this variable could not be accurately adjusted for given the relatively small number of studies available. This review was additionally limited in that no individual study randomized patients by anesthesia type, and that the number of patients requiring general anesthesia and intubation to preserve the airway was not tabulated. Similarly, stroke localization and occlusion site was not assessed. While the results were strongly suggestive that conscious sedation is the preferred method of anesthesia despite confounders, these findings underscored a need for a future randomized controlled trial to examine the effect of anesthesia type on patient mortality or neurologic recovery.

Click to read the study in the American Journal of Neuroradiology

Relevant Reading: Conscious Sedation Versus General Anesthesia During Endovascular Therapy for Acute Anterior Circulation Stroke

In-Depth [systematic review and meta-analysis]: A total of 9 studies regarding the difference in outcomes between general anesthesia and conscious sedation in patients undergoing endovascular treatment for acute ischemic stroke were included in this meta-analysis spanning articles from 1990 to 2010. A total of 1956 patients were pooled, 814 in the general anesthesia arm and 1142 in the conscious sedation arm. The type of endovascular treatment varied across trials, but included the Solitaire stent-retriever, intra-arterial t-PA, mechanical thrombectomy, low-energy ultrasound, or some combination thereof. Study heterogeneity was assessed on the basis of several outcomes; those rated at I² < 50% included symptomatic and asymptomatic intracerebral hemorrhage, death, recanalization success, respiratory complications, indicating insubstantial hetereogeneity. Significant hetereogenity (I² > 50%) was found for procedure time, time to groin puncture, time to resvascularization, and modified Rankin scale score (mRS). As compared to patients undergoing conscious sedation, those who underwent general anesthesia had lower odds of good functional neurologic recovery denoted by a mRS £ 2 (OR = 0.43; p < 0.01), lower odds of successful recanalization (OR = 0.54; p < 0.01), and higher odds of mortality and respiratory complications (OR 2.59 and 2.09 respectively; p < 0.01), without a difference in the odds of intracerebral hemorrhage (OR = 1.34; p = 0.09). No significant differences in any aspect of procedural time were revealed (P = 0.69-1.00). Only six trials tabulated pre-intervention NIHSS scores, however this study did not report the quantitative difference between these baseline values. Attempts to adjust for the difference in baseline NIHSS scores between the study groups with meta-regression yielded a statistically insignificant different odds ratio (OR = 0.38 of having a good functional outcome) than the unadjusted value (OR = 0.43), likely due to loss of statistical power.

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