Indications for and outcomes of therapeutic plasma exchange after cardiac transplantation: A single center retrospective study.

INTRODUCTION: Limited data are available describing indications for and outcomes of therapeutic plasma exchange (TPE) in cardiac transplantation. METHODS: In a retrospective study of patients who underwent cardiac transplantation at Duke University Medical Center from 2010 to 2014, we reviewed 3 TPE treatment patterns: a Single TPE procedure within 24 h of transplant; Multiple TPE procedures initiated within 24 h of transplant; and 1 or more TPE procedures beginning >24 h post-transplant. Primary and secondary outcomes were overall survival (OS) and TPE survival (TS), respectively. RESULTS: Of 313 patients meeting study criteria, 109 (35%) underwent TPE. TPE was initiated in 82 patients within 24 h, 40 (37%) receiving a single procedure (Single TPE), and 42 (38%) multiple procedures (Multiple TPE). Twenty-seven (25%) began TPE >24 h after transplant (Delayed TPE). The most common TPE indication was elevated/positive panel reactive or human leukocyte antigen antibodies (32%). With a median follow-up of 49 months, the non-TPE treated and Single TPE cohorts had similar OS (HR 1.08 [CI, 0.54, 2.14], P = .84), while the Multiple and Delayed TPE cohorts had worse OS (HR 2.62 [CI, 1.53, 4.49] and HR 1.98 [CI, 1.02, 3.83], respectively). The Multiple and Delayed TPE cohorts also had worse TS (HR 2.59 [CI, 1.31, 5.14] and HR 3.18 [CI, 1.56, 6.50], respectively). Infection rates did not differ between groups but was independently associated with OS (HR 2.31 [CI, 1.50, 3.54]). CONCLUSIONS: TPE is an important therapeutic modality in cardiac transplant patients. Prospective studies are needed to better define TPE's different roles in this patient population.

rVWF: treatment finally reaches the modern age.

In this issue of Blood, Gill et al describe the results of the first phase 3 clinical trial evaluating recombinant von Willebrand factor (rVWF) for the treatment of hemorrhagic events in all patients with von Willebrand disease (VWD).

Use of a thrombopoietin mimetic for chronic immune thrombocytopenic purpura in pregnancy.

BACKGROUND: Romiplostim, a thrombopoietin mimetic, is a novel therapeutic option for patients with chronic immune thrombocytopenic purpura. We report on the effects of romiplostim use throughout pregnancy. CASE: A 28-year-old primigravid woman with chronic immune thrombocytopenic purpura initiated a planned pregnancy on romiplostim. The second and third trimesters were marked by a cyclic pattern of thrombocytopenia requiring supplemental corticosteroids or intravenous immunoglobulin and resultant thrombocytosis. Increased romiplostim doses and daily corticosteroids stabilized the platelet count before induction of labor at 33 weeks of gestation. The newborn manifested intraventricular hemorrhage at birth, although no developmental delay was present on follow-up at 10 months of age. CONCLUSION: The decreased efficacy of romiplostim monotherapy is attributed to increased target-mediated drug disposition and the physiologic changes of pregnancy. Safety concerns still exist for the developmental effects of romiplostim on the fetus.

Validation of the high-dose heparin confirmatory step for the diagnosis of heparin-induced thrombocytopenia.

The diagnosis of heparin-induced thrombocytopenia (HIT) requires detection of antibodies to the heparin/platelet factor 4 (PF4) complexes via enzyme-linked immunosorbent assay. Addition of excess heparin to the sample decreases the optical density by 50% or more and confirms the presence of these antibodies. One hundred fifteen patients with anti-heparin/PF4 antibodies detected by enzyme-linked immunosorbent assay were classified as clinically HIT-positive or HIT-negative, followed by confirmation with excess heparin. A multivariate logistic regression model was fitted to estimate relationships between patient characteristics, laboratory findings, and clinical HIT status. This model was validated on an independent sample of 97 patients with anti-heparin/PF4 antibodies. No relationship between age, race, or sex and clinical HIT status was found. Maximal optical density and confirmatory positive status independently predicted HIT in multivariate analysis. Predictive accuracy on the training set (c-index 0.78, Brier score 0.17) was maintained when the algorithm was applied to the independent validation population (c-index 0.80, Brier score 0.20). This study quantifies the clinical utility of the confirmatory test to diagnose HIT. On the basis of data from the heparin/PF4 enzyme-linked immunosorbent assay and confirmatory assays, a predictive computer algorithm could distinguish patients likely to have HIT from those who do not.