Kathy M. Harney

Pediatric Heparin-Induced Thrombocytopenia: prevalence, thrombotic risk, and application of the 4Ts scoring system

OBJECTIVE To characterize heparin-induced thrombocytopenia (HIT) at a single pediatric center including the prevalence and the accuracy of the 4Ts scoring system as a predictor of HIT. STUDY DESIGN In this retrospective cohort study, we identified 155 consecutive patients <21 years old with sufficient data for 4Ts scoring. The 4Ts scoring system is a validated pretest tool in adults that predicts the likelihood of HIT using clinical features. Hospital-wide exposure to unfractionated and low molecular weight heparin was determined by querying the hospital pharmacy database. RESULTS The majority of patients with suspected HIT (61.2%) were on surgical services. Prediction of HIT risk using initial 4Ts scoring found 3 (2%) had high risk 4Ts scores, 114 (73%) had intermediate risk 4Ts scores, and the remaining 38 (25%) had low risk 4Ts scores. HIT was confirmed in 0/38 patients with low risk 4Ts scores, 2/114 patients with intermediate-risk 4Ts scores, and all 3 patients with high-risk 4Ts scores presented with HIT with thrombosis. Of 12 positive HIT screening tests, results were falsely positive in 66.6% of patients with intermediate risk 4Ts scores and 100% of patients with low risk 4Ts scores. The prevalence of HIT was 0.058% and HIT with thrombosis was 0.046% in pediatric patients on unfractionated heparin. CONCLUSIONS The prevalence of HIT appears significantly lower in pediatric patients compared with adults. Application of the 4Ts system as a pretest tool may reduce laboratory evaluation for HIT in heparin-exposed children with low risk 4Ts scores, decreasing unnecessary further testing, intervention, and cost.

Observational Cohort Study of Pediatric Inpatients With Central Venous Catheters at “Intermediate Risk” of Thrombosis and Eligible for Anticoagulant Prophylaxis

The risk of deep vein thrombosis (DVT) among hospitalized children is rising.The optimal approach to DVT prophylaxis in children is unclear. This study set out to ascertain the prevalence of DVT among pediatric inpatients who neither have contraindications to nor absolute indications for prophylactic therapy. A prospective surveillance of at-risk children plus a retrospective chart review were conducted. Patients were considered to be at risk after the first 2 days of their admission. Of 1,637patients reviewed, 198 patients met criteria; among these, 84% did not receive prophylaxis. Of 2,354 observed days at risk for nonprophylaxed patients (including days at risk prior to initiating prophylaxis among prophlyaxed patients), there were 9 DVT events, for a rate 3.82/1,000 days observed. A total of 31 patients received prophylaxis. Three of these patients experienced a DVT. One patient had a bleeding event, hematuria. These results describe patients who may be eligible for prophylaxis and should be screened for further risk factors.

Paget-Schroetter Syndrome in 21 Children: Outcomes after Multidisciplinary Care

OBJECTIVE To review the presentation, management, and outcomes of Paget-Schroetter syndrome (PSS) in children and propose a multidisciplinary treatment algorithm involving pediatric and vascular surgery, interventional radiology, and hematology. STUDY DESIGN Patients with PSS presenting between 2003 and 2013 were reviewed. Demographics, symptoms, therapies, and functional outcomes were noted. Data from early patients informed the development of a multidisciplinary treatment algorithm applied to later patients. RESULTS Of 21 patients, mean ± SD age was 16 ± 1.6 years and 11 (52%) were male. Of patients with complete presentation data, common symptoms were edema (84%), discoloration (58%), and pain (58%). Thrombophilia workup revealed one heterozygote for factor V Leiden, 2 patients with factor VIII elevation and 1 patient with mildly low antithrombin. The most recent 8 patients were treated according to an algorithm developed by a multidisciplinary working group through experience with the first 13 cases. All patients underwent a venogram, endovascular intervention (including 15 receiving catheter-directed thrombolysis), and operative ipsilateral thoracic outlet decompression (first rib resection, anterior scalenectomy, and venolysis). Postoperative complications included hemothorax (2), pneumothorax (1), and recurrent thrombosis (2). Follow up duration was 12 ± 9.5 months. Symptoms recurred transiently in 1 patient. CONCLUSION Pediatric patients with PSS can be treated successfully using a multidisciplinary treatment algorithm including anticoagulation, catheter-directed thrombolysis, and operative decompression of the thoracic outlet. Early outcomes are promising.