Variations in the Use of Transcranial Doppler and Chronic Transfusion Therapy for Stroke Prevention in Pediatric Populations at Sickle Cell Centers.

Abstract

The Stroke Prevention Trial in Sickle Cell Anemia (STOP I) demonstrated a 90% risk reduction of first stroke in high-risk pediatric patients with sickle cell disease (SCD) receiving chronic transfusion therapy (CTT) (Adams RJ et al. N Engl J Med 1998; 339:5–11). Transcranial Doppler (TCD) is key in assessing the need for CTT in children with SCD. A survey of the American Society of Pediatric Hematology/Oncology found wide variation in how hematologists are managing children with SCD (Lane PA et al. Blood 2001; 98:784a). Recent recommendations by the National Heart, Lung and Blood Institute (NHLBI) suggest TCD and CTT for stroke prevention in high-risk children with SCD; however, there are no data on the utilization of these guidelines in clinical practice. Therefore, we conducted a telephone survey of Sickle Cell Centers to assess the clinical use of TCD and CTT for stroke prevention in pediatric patients with SCD. Invitations to participate were mailed to Directors of 70 centers; interviews were conducted between December 7, 2005 and February 10, 2006. Results from 25 participating centers were analyzed for trends related to use of TCD and CTT in the care of children with SCD. Questions included frequency of TCD based on velocity: <170 cm/sec, 170–200 cm/sec, and >200 cm/sec (Table). Because some participants could not provide an accurate response, responses are not available for all 25 centers in some cases.Frequency of TCDSickle Cell CentersN = 25TCD <170 cm/secRepeat every 6 mo4Repeat yearly13Repeat every 1–2 y4Repeat every 2 y1TCD 170–200 cm/secRepeat every mo7Repeat every 2 mo3Repeat every 3 mo6Repeat every 4–5 mo3Repeat every 6 mo6TCD >200 cm/secRepeat every mo14Repeat every 2 mo1Repeat every 3 mo3Based on clinical observations, participants estimated the percentage of patients with eventual worsening of TCD velocity to >200 cm/sec and the approximate number of months to reach that endpoint. Responses indicated an average of 23% and 11.3 months, respectively. Of the 25 centers, all but one indicated that patients with an abnormal TCD (>200 cm/sec) were typically placed on CTT. Four participants stated that results from the STOP trial were the basis for their decision. Fifteen centers indicated that the youngest age they would initiate CTT was 1–2 years. Only 2 directors would consider CTT in children <1 year, and 3 would not initiate CTT until age 5. Although the NHLBI guidelines suggest a hemoglobin S (Hb S) target of <30%, only 5 directors stated that this was their primary factor in determining frequency of CTT. In terms of typical CTT duration, 68% said therapy was indefinite or lifelong, 20% said <1 year, 4% said 2 years, and 4% said until age 18. Although the number of participants was limited, responses indicate there is a relatively wide variation in the application of the NHLBI recommendations for TCD use and CTT in pediatric patients with SCD. The importance of these findings should be correlated both with a more extensive sample of SCD centers and the reported incidence of stroke in the pediatric population.