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Relative anemia and perioperative stroke in children with moyamoya
John R Gatti1, Syed Ameen Ahmad1, Sarah Gardner Yelton2
1Johns Hopkins School of Medicine, Baltimore, MD, USA.
Insights
Decreased hemoglobin and hematocrit levels after moyamoya arteriopathy surgery in children increase stroke risk. Dilutional anemia from hyperhydration may be a factor, necessitating optimized fluid management and transfusion strategies.
Area of Science:
- Pediatric Neurosurgery
- Vascular Neurology
- Critical Care Medicine
Background:
- Surgical revascularization for moyamoya arteriopathy reduces long-term stroke risk.
- Perioperative ischemic complications are a known risk of this surgery in children.
Purpose of the Study:
- To identify modifiable risk factors for perioperative stroke in pediatric moyamoya patients.
- To analyze associations between specific physiological changes and stroke occurrence.
Main Methods:
- Retrospective cohort study of pediatric moyamoya patients (2003-2021).
- Analysis of 53 surgical procedures for associations with perioperative ischemic stroke (≤7 days post-op).
- Evaluation of candidate modifiable risk factors, including hemoglobin and hematocrit changes.
Main Results:
- Perioperative ischemic stroke occurred in 9.4% of surgeries.
- Significant increases in stroke risk were linked to greater pre- to postoperative decreases in hemoglobin, hematocrit, and blood urea nitrogen.
- Weight-adjusted intraoperative blood loss and sickle cell disease (with prior exchange transfusion) were not associated with increased stroke risk.
Conclusions:
- Pre- and postoperative decreases in hemoglobin, hematocrit, and blood urea nitrogen are novel risk factors for perioperative stroke in pediatric moyamoya patients.
- Dilutional anemia, potentially from hyperhydration, may contribute to stroke risk.
- Further research is needed to optimize perioperative management, including fluid balance and transfusion thresholds.
Objectives:
Surgical revascularization for moyamoya arteriopathy decreases long-term stroke risk but carries a risk of perioperative ischemic complications. We aimed to evaluate modifiable stroke risk factors in children undergoing surgical revascularization for moyamoya.
Materials And Methods:
In this exploratory, single-center, retrospective cohort study, medical records of pediatric patients undergoing surgical revascularization for moyamoya arteriopathy at our center between 2003 and 2021 were reviewed. Candidate modifiable risk factors were analyzed for association with perioperative stroke, defined as ischemic stroke ≤7 days after surgery.
Results:
We analyzed 53 surgeries, consisting of 39 individual patients undergoing indirect surgical revascularization of 74 hemispheres. Perioperative ischemic stroke occurred following five surgeries (9.4%). There were no instances of hemorrhagic stroke. Larger pre-to-postoperative decreases in hemoglobin (OR 3.90, p=0.017), hematocrit (OR 1.69, p=0.012) and blood urea nitrogen (OR 1.83, p=0.010) were associated with increased risk of perioperative ischemic stroke. Weight-adjusted intraoperative blood loss was not associated with risk of perioperative ischemic stroke (OR 0.94, p=0.796). Among children with sickle cell disease, all of whom underwent exchange transfusion within one week prior to surgery, none experienced perioperative stroke.
Conclusions:
Decreases in hemoglobin, hematocrit, and blood urea nitrogen between the preoperative and postoperative periods are associated with increased risk of perioperative stroke. These novel findings suggest that dilutional anemia, possibly due to standardly administered hyperhydration, may increase the risk of perioperative stroke in some children with moyamoya. Further work optimizing both mean arterial pressure and oxygen-carrying capacity in these patients, including consideration of alternative blood transfusion thresholds, is necessary.
