Interplay between anemia parameters and collateral status in patients who undergo mechanical thrombectomy

Anemia and Optimal Transfusion Thresholds in Brain-Injured Patients: A Narrative Review of the Literature

Anemia is a highly prevalent condition that may compromise oxygen delivery to vital organs, especially among the critically ill. Although current evidence supports the adoption of a restrictive transfusion strategy and threshold among the nonbleeding critically ill patient, it remains unclear whether this practice should apply to the brain-injured patient, given the predisposition to cerebral ischemia in this patient population, in which even nonprofound anemia may exert a detrimental effect on clinical outcomes. The purpose of this review is to provide an overview of the pathophysiological changes related to impaired cerebral oxygenation in the brain-injured patient and to present the available evidence on the effect of anemia and varying transfusion thresholds on the clinical outcomes of patients with acute brain injury.

Hemoglobin in large vessel occlusion: Look further than collaterals

BACKGROUND

Abnormal hemoglobin (Hb) levels lead to poorer outcomes in ischemic stroke, though the mechanisms remain elusive. We aimed to study the role of Hb on imaging and clinical outcomes, namely on collaterals as it is a known mediator of infarct growth.

METHODS

Retrospective cohort study of patients with large vessel occlusion ischemic stroke admitted to our center. Demographics, clinical and imaging variables were collected, particularly baseline hemoglobin, presence of anemia and collateral score. Collaterals were scored from 0 to 3 and defined as poor if 0-1. Multivariable analyses were performed for collateral score and clinical outcomes (3-month mortality and good prognosis).

RESULTS

We included 811 patients, 215 (26.5 %) with anemia. Patients with anemia were older, had more comorbidities and more severe strokes. Hemoglobin levels and anemia were not associated with collateral score (OR 0.97, 95 % CI 0.89-1.05, p = 0.414 and OR 0.89, 95 % CI 0.64-1.24, p = 0.487, respectively) nor with poor collaterals (OR 0.96, 95 % CI 0.88-1.05, p = 0.398 and OR 0.86, 95 % CI 0.60-1.23, p = 0.406, respectively). Hb levels were associated with 3-month mortality (OR 0.85, 95 % CI 0.76-0.96, p = 0.008).

CONCLUSION

Hemoglobin or anemia were not found to be associated with collateral status. Our results raise further questions regarding the pathophysiology of anemia and outcomes in ischemic stroke, highlighting the need for future research.

Association Between Anemia and Clinical Outcome in Acute Ischemic Stroke Patients Treated With Endovascular Treatment

BACKGROUND AND PURPOSE

Endovascular treatment (EVT) is the preferred treatment option in eligible acute ischemic stroke (AIS) patients with a large vessel occlusion of the anterior circulation. Several comorbidities have been identified that can affect clinical outcomes. Various studies have investigated the association between anemia and clinical outcome and found conflicting.

RESULTS

. The aim is to investigate the association between pre-EVT anemia and clinical outcomes at different time points post-EVT, primarily focusing on the National Institutes of Health Stroke Scale (NIHSS) at 24-48 hours.

METHODS

We prospectively included 560 AIS patients who received EVT in the Maastricht University Medical Center+. Hemoglobin levels (Hb; g/dL) were determined on admission. Hb levels were also categorized into two groups: anemia (male: Hb ≤12.9 g/dL; female: Hb ≤11.9 g/dL) and no anemia. Multiple imputation was used to handle missing data. Multivariable regression was used to investigate the association between anemia or Hb levels and clinical outcomes.

RESULTS

Anemia was present in 26% of the patients. Multivariable regression did not show a significant association between anemia or Hb levels and NIHSS at 24-48 hours (adjusted β [aβ]anemia: 1.44, 95% confidence interval [CI]: -0.47 to 3.36; aβHb: -0.37, 95% CI: -0.88 to 0.13). However, multivariable regression showed significant associations with modified Rankin Scale (adjusted common odds ratio [acOR]anemia: 1.66, 95% CI: 1.12 to 2.48; acORHb: 0.83, 95% CI: 0.75 to 0.93) and poor functional outcome at 90 days (adjusted OR [aOR]anemia: 2.09, 95% CI: 1.21 to 3.63; aORHb: 0.80, 95% CI: 0.69 to 0.92).

CONCLUSION

Anemia was not independently associated with early neurological deficit (NIHSS) post-AIS, suggesting it is more suitable as a general frailty marker.

Association of blood pressure parameters post mechanical thrombectomy in anemic versus non-anemic patients and clinical outcomes

INTRODUCTION

Higher blood pressure (BP) is considered to be detrimental in patients who undergo mechanical thrombectomy (MT), however, the impact of BP post-MT based on comorbidities like anemia has not been well studied. We aim to determine the association of 24-h post-MT BP parameters with clinical outcomes depending on their anemia status.

METHODS

We conducted a retrospective chart review of patients who underwent MT at a comprehensive stroke center from 1/2015 to 12/2020. Patients were dichotomized into anemic and non-anemic groups based on the World Health Organization's definition of anemia [hemoglobin < 12.0 g/dL in women and < 13.0 g/dL in men]. We performed a multivariable analysis with binary logistic regression with the 24-h post-MT BP parameters as predictors. The outcomes were functional dependence (3-month mRS 3-6), mortality, and an early neurological improvement.

RESULTS

220 patients met the inclusion criteria. 158 (71.82 %) patients had functional dependence at 3-months. In the multivariable analysis, the parameters of a higher mean SBP (132.9 ± 11.94 vs.126.52 ± 13.3; OR, 1.05; 95 % CI, 1.02-1.09; P 0.011), a higher mean MAP (93.35 ± 8.44 vs.89.69 ± 10.03; OR,1.06; 95 % CI, 1.01-1.11; P 0.029) and a higher maximum MAP (115.26 ± 11.73 vs.109.37 ± 12.51; OR,1.05; 95 % CI, 1.01-1.08; P 0.023)were significantly associated with functional dependence in non-anemic patients, while a lower mean DBP (65.53 ± 9.73 vs. 71.94 ± 10.16; OR, 0.92; 95 % CI, 0.86-0.98; P 0.007), lower mean MAP (85.7 ± 8.65 vs. 91.38 ± 10; OR, 0.93; 95 % CI, 0.86-0.99; P 0.02), a lower minimum DBP (49.27 ± 10.51 vs. 55.1 ± 11.23; OR, 0.93; 95 % CI, 0.88-0.99; P 0.019), a lower minimum MAP (68.96 ± 9.54 vs. 74.73 ± 10.47; OR, 0.93; 95 % CI, 0.87-0.99; P 0.023) were significantly associated with mortality in patients with anemia, and a lower minimum DBP (54.75 ± 10.42 vs. 59.69 ± 8.87; OR, 0.95; 95 % CI, 0.91-0.99; P 0.012) and a lower minimum MAP (71.92 ± 14.7 vs.75.67 ± 14.17; OR, 0.97; 95 % CI, 0.94-0.99; P 0.047) were significantly associated with an early neurological improvement in non-anemic patients. For patients with anemia, there was no association between 24-hour BP Parameters post-MT and functional dependence and early neurological improvement, and between 24-hour BP Parameters post-MT and mortality in non-anemic patients.

CONCLUSION

In our study, higher BP parameters were associated with worse outcomes in patients without anemia, however, this effect was not found in patients with anemia. Certain lower BP parameters were associated with higher 3-month mortality in anemic patients; however, this effect was not found in non-anemic patients. Higher BP post-MT can potentially promote perfusion and thus is not associated with worse outcomes in anemic patients post-MT, whereas in non-anemic patients it may potentially lead to reperfusion injury While our study is limited because of size and its retrospective nature, the findings suggest that an individualized approach to tailor the target BP post-MT to a patient's risk factor profile and associated co-morbid conditions to achieve optimization of medical care post-MT and associated co-morbid conditions to achieve optimization of medical care post-MT.