Different unfractionated heparin doses for preventing arterial thrombosis in children undergoing cardiac catheterization

A multi-step approach to the treatment of giant scalp congenital hemangiomas: a report of two cases

This is a review of two cases of neonatal giant scalp congenital hemangioma. Both patients were treated with propranolol using a similar multi-step approach that included transarterial embolization of the supplying arteries followed by surgical resection of the lesion. In this report, we discuss the treatments, complications, and clinical outcomes of interventions and surgical procedures.

Different unfractionated heparin doses for preventing arterial thrombosis in children undergoing cardiac catheterization

BACKGROUND

The role of cardiac catheterization in pediatrics has progressed significantly over the last two decades, evolving from a primary diagnostic tool to a primary treatment modality in children with congenital heart disease. Vascular complications, particularly arterial thrombosis, are among the most common unwanted post-cardiac catheterization events. In 1974, unfractionated heparin proved to be superior to placebo in decreasing the incidence of arterial thrombosis in pediatric patients. However, the optimal dose of unfractionated heparin to be utilized in this setting remains a matter of controversy. This is an update of the review first published in 2014.

OBJECTIVES

To evaluate the use of low-dose (< 100 units/kg) versus high-dose (≥ 100 units/kg) unfractionated heparin administered as an intravenous bolus at the time of initiation of cardiac catheterization (that is, immediately after arterial puncture), with or without subsequent heparin maintenance doses, for the prevention of post-procedural arterial thrombosis in children.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase and CINAHL databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 15 October 2019. We planned to undertake reference checking of identified trials to identify additional studies. No language restrictions were applied.

SELECTION CRITERIA

We included randomized or quasi-randomized trials that compared low dose to high dose unfractionated heparin administered prior to cardiac catheterization. We selected studies conducted in children aged 0 to 18 years.

DATA COLLECTION AND ANALYSIS

The first screening of potentially eligible studies was conducted by one of the authors (MLA). The second screening, risk of bias assessment and data extraction were independently conducted by two authors (MLA, LRB). Outcomes (thrombotic events, bleeding complications, other complications) were treated as dichotomous variables. The effect measures used were risk ratio (RR), risk difference (RD) and number needed to treat (NNT), with 95% confidence intervals (CI). We assessed the certainty of evidence for each outcome using the GRADE approach.

MAIN RESULTS

We identified no new studies for inclusion in this review. In total, two studies with a total of 492 participants were included. We had concerns about risk of bias for one of the two studies. The certainty of the evidence for our key outcomes was downgraded to moderate due to risk of bias concerns and imprecision. The confidence interval for the risk of arterial thrombotic events was compatible with benefits of either high or low unfractionated heparin dose regimens (RR low-dose versus high-dose 1.06, 95% CI 0.58 to 1.92). Only one of the studies reported the frequency of bleeding events and found no clear difference in the incidence of major or minor bleeding events between arms (RR low-dose versus high-dose 2.96, 95% CI 0.12 to 71.34 for major bleeding events; RR low-dose versus high-dose 1.38, 95% CI 0.46 to 4.13 for minor bleeding). This study also reported on the incidence of deep vein thrombosis when comparing the high versus low dose of heparin and reported a non-significant difference (RR low-dose versus high-dose 0.34, 95% CI 0.01 to 8.28). The other study lacked information about bleeding. Additional side effects of heparin other than bleeding events were not reported in either of the studies.

AUTHORS' CONCLUSIONS

Due to the limitations of the current evidence, small number of included studies, and lack of details reported in one study, we are unable to determine the effects of different dosing regimens of unfractionated heparin for the prevention of vascular thrombosis during cardiac catheterization in children. Further adequately powered, randomized clinical trials are needed.

Development and Implementation of a Standardized Heparin Protocol for Left-Sided Pediatric Electrophysiology Procedures

Heparin is used to decrease the risk of thromboembolic complications during electrophysiology studies (EPS); however, there is wide practice variation and minimal evidence to guide heparin dosing, particularly in pediatric patients. This study retrospectively analyzed heparin dosing and response, measured via activated clotting time (ACT), in patients undergoing EPS and used these data (pre-protocol cohort, n = 40), as well as guidance from available literature to implement a standardized heparin protocol (phase 1, n = 43). We utilized quality improvement methodology to refine this protocol (phase 2, n = 40) to improve therapeutic heparin response. Prior to the protocol, patients achieved therapeutic ACT levels (250-350 s) only 35% of the time which improved to 60% during phase 1 (p < 0.05) and to 73% during phase 2 (p < 0.001 compared to pre-protocol). There were no thromboses or significant adverse events in any group. These results demonstrate the effectiveness of a standardized heparin protocol in achieving effective antithrombotic therapy during left-sided pediatric EPS.

Potential and Limitations of Cochrane Reviews in Pediatric Cardiology: A Systematic Analysis

Evidence-based medicine has contributed substantially to the quality of medical care in pediatric and adult cardiology. However, our impression from the bedside is that a substantial number of Cochrane reviews generate inconclusive data that are of limited clinical benefit. We performed a systematic synopsis of Cochrane reviews published between 2001 and 2015 in the field of pediatric cardiology. Main outcome parameters were the number and percentage of conclusive, partly conclusive, and inconclusive reviews as well as their recommendations and their development over three a priori defined intervals. In total, 69 reviews were analyzed. Most of them examined preterm and term neonates (36.2%), whereas 33.3% included also non-pediatric patients. Leading topics were pharmacological issues (71.0%) followed by interventional (10.1%) and operative procedures (2.9%). The majority of reviews were inconclusive (42.9%), while 36.2% were conclusive and 21.7% partly conclusive. Although the number of published reviews increased during the three a priori defined time intervals, reviews with "no specific recommendations" remained stable while "recommendations in favor of an intervention" clearly increased. Main reasons for missing recommendations were insufficient data (n = 41) as well as an insufficient number of trials (n = 22) or poor study quality (n = 19). There is still need for high-quality research, which will likely yield a greater number of Cochrane reviews with conclusive results.

Prevalence of post-thrombotic syndrome after cardiac catheterization

BACKGROUND

As the survival of children with cardiac disease increases, chronic complications of deep venous thrombosis from cardiac catheterization, particularly post-thrombotic syndrome, may be important to monitor for and treat, if needed. We aimed to determine the prevalence of this syndrome in children who underwent cardiac catheterization.

PROCEDURE

We conducted a cross-sectional study of children <18 years old at least 1 year from first catheterization through the femoral vein. We used the Manco-Johnson instrument, the only tool validated in children, to diagnose post-thrombotic syndrome. We defined the syndrome as a score ≥ 1. It was considered physically and functionally significant if the score was ≥ 1 in both physical and functional domains of the instrument. We also conducted ultrasonography to assess for thrombosis and valvular insufficiency.

RESULTS

We enrolled 62 children with a median age of 4 months during catheterization and a median of 5.4 years since catheterization. A total of 40 children had post-thrombotic syndrome (prevalence: 64.5%; 95% confidence interval: 51.3-76.3%), the majority of which were mild. Presence of cyanotic congenital heart disease, total number of catheterizations, use of antithrombotic agents at any time after the first catheterization, age at first catheterization, or time since first catheterization was not associated with the syndrome. A total of seven children (prevalence: 11.3%; 95% confidence interval: 3.2-19.4%) had physically and functionally significant syndrome. None of the children had abnormalities on ultrasonography at the time of enrollment.

CONCLUSIONS

Post-thrombotic syndrome is a common complication after cardiac catheterization. Manifestations are usually mild and unlikely to require treatment.