Repair of the mitral valve because of pure rheumatic mitral valvar incompetence in the young

Outcomes After Rheumatic Mitral Valve Repair in Children

BACKGROUND

It has been shown that mitral valve repair is superior to mechanical replacement in children with rheumatic heart disease; however there are limited data on the factors affecting the long-term durability of repaired mitral valves. This study describes outcomes after rheumatic mitral valve repair, with adaptation of a risk score to clarify some novel predictors of repair instability.

METHODS

A total of 79 children (median age, 11.4 years) with rheumatic heart disease underwent their first mitral valve surgery between 1997 and 2015. Patients with concomitant aortic and tricuspid repair were included. Mean follow-up time was 7.72 years. Mitral valve deterioration (defined as cardiac death, reoperation, or recurrent moderate to severe valvular disease) was used as a key end point. Preoperative echocardiographs were analyzed and graded with respect to valvular mobility, subvalvular apparatus alteration, and function.

RESULTS

All patients underwent successful mitral valve repair. Seven patients died during follow-up. Kaplan-Meier analysis demonstrated survival at 15 years to be 83%. A total of 38 patients were deemed to have deterioration in mitral valve function, with a rate of freedom from deterioration at 15 years of 28%. The presence of an immobile anterior mitral leaflet preoperatively and the technique of posterior patch extension were shown to be significant determinants of mitral valve deterioration.

CONCLUSIONS

The outcomes after mitral repair for rheumatic heart disease in the young were in keeping with those reported in previous studies. Although the survival was high, long-term valve stability was poor. These findings suggest that the preoperative finding of a restricted anterior mitral leaflet is a negative predictor of repair durability.

Platelet Inhibition in Shunted Infants on Aspirin at Short and Midterm Follow-Up

There are few data to guide aspirin therapy to prevent shunt thrombosis in infants. We aimed to determine if aspirin administered at conventional dosing in shunted infants resulted in ≥50% arachidonic acid (AA) inhibition in short and midterm follow-up using thromboelastography with platelet mapping (TEG-PM) and to describe bleeding and thrombotic events during follow-up. We performed a prospective observational study of infants on aspirin following Norwood procedure, aortopulmonary shunt alone, or cavopulmonary shunt surgery. We obtained TEG-PM preoperatively, after the third dose of aspirin, at the first postoperative clinic visit, and 2-8 months after surgery. The primary outcome was the proportion of subjects with ≥50% AA inhibition on aspirin. All bleeding and thrombotic events were collected. Of 24 infants analyzed, 13% had ≥50% AA inhibition at all designated time points after aspirin initiation; 38% had ≥50% AA inhibition after the third aspirin dose of aspirin, 60% at the first postoperative clinic visit, and 26% 2-8 months after surgery. Bleeding events occurred in eight subjects, and two had a thrombotic event. Bleeding events were associated with greater AA inhibition just prior to starting aspirin (p = 0.02) and after the third dose of aspirin (p = 0.04), and greater ADP inhibition before surgery (p = 0.03). The majority of infants failed to consistently have ≥50% AA inhibition when checked longitudinally postoperatively. Preoperative TEG-PM may be useful in identifying infants at higher risk of bleeding events on aspirin in the early postoperative period. Further research is needed to guide antiplatelet therapy in this population.

Clopidogrel in infants with systemic-to-pulmonary-artery shunts

BACKGROUND

Infants with cyanotic congenital heart disease palliated with placement of a systemic-to-pulmonary-artery shunt are at risk for shunt thrombosis and death. We investigated whether the addition of clopidogrel to conventional therapy reduces mortality from any cause and morbidity related to the shunt.

METHODS

In a multicenter, double-blind, event-driven trial, we randomly assigned infants 92 days of age or younger with cyanotic congenital heart disease and a systemic-to-pulmonary-artery shunt to receive clopidogrel at a dose of 0.2 mg per kilogram of body weight per day (467 infants) or placebo (439 infants), in addition to conventional therapy (including aspirin in 87.9% of infants). The primary efficacy end point was a composite of death or heart transplantation, shunt thrombosis, or performance of a cardiac procedure due to an event considered to be thrombotic in nature before 120 days of age.

RESULTS

The rate of the composite primary end point did not differ significantly between the clopidogrel group (19.1%) and the placebo group (20.5%) (absolute risk difference, 1.4 percentage points; relative risk reduction with clopidogrel, 11.1%; 95% confidence interval, -19.2 to 33.6; P=0.43), nor did the rates of the three components of the composite primary end point. There was no significant benefit of clopidogrel treatment in any subgroup, including subgroups defined by shunt type. Clopidogrel recipients and placebo recipients had similar rates of overall bleeding (18.8% and 20.2%, respectively) and severe bleeding (4.1% and 3.4%, respectively).

CONCLUSIONS

Clopidogrel therapy in infants with cyanotic congenital heart disease palliated with a systemic-to-pulmonary-artery shunt, most of whom received concomitant aspirin therapy, did not reduce either mortality from any cause or shunt-related morbidity. (Funded by Sanofi-Aventis and Bristol-Myers Squibb; ClinicalTrials.gov number, NCT00396877.).

Antiplatelet therapy in pediatric cardiovascular patients

Platelets play a critical role in normal physiologic processes such as hemostasis, wound healing, inflammation, and innate immunity. However, they also play a role in the pathologic process of thrombosis. Although antiplatelet therapy is most commonly used to prevent thrombotic events for adults with atherosclerotic vascular disease, children with certain types of congenital heart disease, stroke, and Kawasaki disease also are at risk for thrombosis and may benefit from antiplatelet therapy. Unfortunately, very little data on the efficacy and safety of antiplatelet therapy for pediatric patients are available. As a consequence, consistent clinical practice among pediatric practitioners is lacking. Furthermore, much of what is practiced results from extrapolation from adult studies, which may be problematic because many aspects of platelet biology differ between children and adults. This review discusses aspects of antiplatelet therapy for pediatric patients.

Congenital heart disease: current indications for antithrombotic therapy in pediatric patients

This report reviews the current status of antithrombotic therapy, including anti-platelet therapy, in pediatric patients with congenital heart disease. The current medications utilized and dose recommendations are emphasized, and indications for their use are reviewed.