Flat Head Positioning Before Thrombectomy Linked to Better Long-Term Stroke Outcomes

Anne Alexandrov, PhD, RN

A recently published randomized trial (NCT03728738) of patients with large vessel occlusion (LVO) stroke revealed that a 0° head position prior to endovascular thrombectomy (EVT) was safe and the most optimal positioning to prevent clinical worsening. In comparison, a 30° head position led to a 34.4-fold increased risk of clinical worsening prior to initiating EVT.¹

Published in JAMA Neurology, the ZODIAC trial included 92 patients (mean age, 66.6 years) who were randomly assigned to either 0° (n = 45) or 30° (n = 47) head positioning with monitoring every 10 minutes using the National Institutes of Health Stroke Scale (NIHSS). Despite similar patient characteristics between the groups, those assigned to 30° head position demonstrated early neurological deterioration, defined by NIHSS change of 2 points or more, while those assigned to flat head-of-bed positioning maintained stable scores (HR, 34.40; 95% CI, 4.65-254.37; P <.001).

"Our findings may be important for future LVO trials enabling standardized head positioning before thrombectomy," Anne Alexandrov, PhD, RN, a professor and U.T Mobile Stroke Unit Chief Nurse Practitioner at the University of Tennessee Health Science Center, and others, wrote. "We have shown previously and in this trial that 0° positioning is low risk, favoring arguments for widespread adoption to minimize neurologic deterioration before thrombectomy. Because most patients arrive with heads elevated, training of emergency personnel, helicopter, and ground transport teams should accompany implementation to ensure compliance with this simple, protective maneuver."

The study included only those with CT angiography-positive anterior or posterior LVO who were candidates for thrombectomy (baseline modified Rankin scale [mRs], 0-1) and had viable penumbra within 24 hours of stroke onset. In the trial, all patients underwent standard of care CT and CTA with or without CT perfusion per local standard.

Upon hospital arrival, 77.2% of subsequently enrolled patients (71 of 92) were received from transport teams with their heads positioned at 30°. Coming into the study, most patients (97.8%) had prestroke mRS scores of 0 to 1, both groups had similar NIHSS scores, and the time from hospital arrival to assigned position was balanced between cohorts. Excluding patients with unknown time of onset, those with a head position at 0° were consented later after developing stroke symptoms than those with a head position at 30° (mean time, 221.27 [SD, 175.46] minutes vs 124.57 [SD, 85.67] minutes [95% CI, 31.96-161.44 minutes]).

On the primary outcome, 1 patient in the 0° group and 26 patients in the 30° group had NIHSS worsening of at least 2 or more points. At the discretion of local neurointerventionalists, 15 patients (33.3%) in the 0° group and 8 patients (17.0%) in the 30° group (P = .09) did not undergo thrombectomy. While there were no significant between-group differences in eTICI scores, all 30 patients who underwent thrombectomy in the 0° group achieved eTICI 2b50 to 3 scores on the final postprocedure angiographic runs vs 87.2% (34 of 39) of those in the 30° group (P = .06).

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Additional secondary safety data from the study showed that 20 patients in the 30° group had NIHSS score worsening of 4 or more points during positioning, compared with only 1 patient in the 0° group (HR, 23.57; 95% CI, 3.16-175.99; P = .002). All-cause death over the 90-day study period occurred in 2 patients (4.4%) in the 0° group compared with 10 patients (21.7%; P = .03) in the 30° group.

At 24 hours post-thrombectomy, 86.7% of patients in the 0° group showed NIHSS improvement vs 59.6% in the 30° group (OR, 0.24; 95% CI, 0.08–0.68; P = .01). This benefit persisted at discharge/day 7 (86.7% vs 66.0%; OR, 0.32; 95% CI, 0.11–0.92; P = .03). By 3 months, 68.9% in the 0° group vs 56.5% in the 30° group had an mRS of at least 2 (OR, 0.59; 95% CI, 0.25–1.39; P = .22).

Alexandrov et al previously tested the theory of 0° head position in a pilot study, published in 2005. The study, which employed a repeated-measures quasi-experiment, evaluated the effect of 30, 15, and 0° positions on middle cerebral artery (MCA) mean flow velocity (MFV) in 20 patients with acute ischemic stroke. In the study, lower head-of-the-bed positions led to better results, with MCA MFV increased by 20% (12% from 30 to 15° and 8% from 15 to 0°; P ≤.025).²

In the pilot study, immediate neurologic improvement, considered average 3 NIHSS motor points, occurred in 3 patients (15%) after lowering head position. Data also revealed no changes to mean arterial pressure, heart rate, and pulsatility index (PI), indicating no increase to resistance to blood flow. Overall, MCA MFV was increased in all patients with lowering head position (maximum absolute MFV value increase 27 cm/s, range 5 to 96% from baseline values at 30°).

REFERENCES
1. Alexandrov AW, Shearin AJ, Mandava P, et al. Optimal Head-of-Bed Positioning Before Thrombectomy in Large Vessel Occlusion Stroke: A Randomized Clinical Trial. JAMA Neurol. Published online June 4, 2025. doi:10.1001/jamaneurol.2025.2253
2. Wojner-Alexander AW, Garami Z, Chernyshev OY, et al. Heads down Flat positioning improves blood flow velocity in acute ischemic stroke. Neurology. 2005;64(8):1354-1357. doi:10.1212/01.WNL.0000158284.41705.A5