Investigate clinical and radiological abnormalities that may identify increased risk for stroke in patients who underwent stem cell transplantation (SCT) at two large centers.

Sickle cell disease (SCD) is a common hematological disease that frequently results in serious neurological complications including various cerebrovascular complications.

We evaluated two SCD registries to determine the risk factors for stroke in patients who underwent SCT. We studied the clinical, hematological and radiological finding in of all the patients who had the procedure treated between 2011 and 2022. Imaging abnormalities included the presence of small vessel disease (SVD), cerebral microbleeds (CMBs), vasculopathy and Moyamoya angiopathy (MMA). We used the Fazekas score to quantify SVD in both groups.

There were 704 patients with SCD who had SCT during the study period (pediatric 181 and adult 523), 267 (37.9%) were female. Out of 704, 169 patients (24%) had stroke evident on imaging prior to SCT. Age, gender distribution, and blood pressure (sBP/dBP) were similar between the two groups. Vascular risk factors, including a history of diabetes, hypertension, dyslipidemia and smoking were also similar in both groups. The presence of high-burden SVD (OR 10.3, [95% CI, 2.7-39.3], p = 0.001), vasculopathy (OR 10.2, [95% CI, 4.17-25.12], p < 0.001),  Moyamoya angiopathy (OR 7.9, [95% CI, 2.7-22.5], p < 0.001)  and cerebral microbleeds (CMBs) (OR 3.9, [95% CI, 1.4-10.5], p = 0.006) and hemoglobin S (OR 1, [95% CI, 0.95-0.98], p < 0.001) were the most important factors associated with a risk of stroke.

Higher rates of SVD, CMBs and vasculopathy on imaging were significantly associated with a higher risk for ischemic stroke. Our findings indicate that using neuroimaging features may be helpful in selecting or prioritizing SCT for SCD patients.