Anesthesia choices could contribute to endovascular stroke therapy outcomes
MedWire News: Patients undergoing endovascular therapy for stroke caused by large vessel occlusions may have better outcomes if given general rather than local anesthesia, research suggests.
However, this was closely linked to patients' blood pressure. The type of anesthesia used predicted outcomes even after adjusting for stroke severity, but systolic blood pressure below 140 mmHg was linked to both use of general anesthesia and poor patient outcomes.
The average lowest recorded systolic blood pressure was 104 mmHg in 48 patients given general anesthesia, compared with 134 mmHg in 48 given local anesthesia. Also, the lowest systolic blood pressure was at least 140 mmHg in 60% of patients given local anesthesia versus just 4% of those given general anesthesia.
In an editorial accompanying the study in Anesthesiology, Eric Heyer (Columbia University, College of Physicians and Surgeons, New York, USA) say that this is "the first study to find that systolic blood pressures less than 140 mmHg significantly contributed to poor outcome." They add: "In our opinion, this is the most important result of this study."
They say that induction of general anesthesia often provokes a reduction in blood pressure, adding that "a decrease in blood pressure may have exaggerated consequences [in stroke patients] because of the loss of cerebral autoregulation and reliance on collateral circulation."
The maximum systolic blood pressure was similar in the two groups, at 165 and 162 mmHg in patients given general and local anesthesia, respectively.
Melinda Davis (Foothills Medical Center, Calgary, Alberta, Canada) and team followed up 96 patients who underwent endovascular therapy for stroke at their institution and had available modified Rankin Scale (mRS) scores at 3 months. Of these, 39% were functionally independent, with mRS scores of 0-2. Just 15% of patients given general anesthesia achieved functional independence, compared with 60% of those given local anesthesia.
Use of general anesthesia increased significantly in line with stroke severity. But after accounting for stroke severity and other variables, general versus local anesthesia was associated with a 69% reduction in the likelihood of patients achieving functional independence.
In a separate model, which omitted anesthesia but included blood pressure (as the two correlated), patients with a lowest recorded systolic blood pressure below 140 mmHg were 61% less likely to achieve functional independence relative to those who maintained higher blood pressures.
Heyer et al comment: "Although the study stated that the goals of blood pressure management are to maintain blood pressures within 10% the patient's baseline values, it is highly probable that this goal was not met during the induction of general anesthesia. These results underline the importance of avoiding hypotension in these patients."
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By Eleanor McDermid