Jennifer A. Su

Extracorporeal membrane oxygenation support after pediatric orthotopic heart transplantation.

Mechanical circulatory support has been used for more than 30 yr to allow the heart to recover from ischemia and injury. There are limited pediatric data, however, on the efficacy of ECMO in the setting of post‐transplantation support for primary graft dysfunction or rejection. Data from all patients at our university‐affiliated, tertiary care childrens hospital who underwent OHT between 1998 and 2010 and required subsequent ECMO support were analyzed. The primary outcome measure was survival to hospital discharge. Two hundred and three pediatric patients underwent OHT between 1998 and 2010 at our institution. Twenty‐nine of these patients experienced post‐transplantation cardiac failure requiring ECMO support, 18 of whom survived to hospital discharge (62%). Survival in the rejection and allograft vasculopathy group was 75%, and survival in patients with primary graft failure was 53% after ECMO support (p = 0.273). Patient survival to hospital discharge was not associated with ischemic time or duration of ECMO. ECMO provides hemodynamic support in the setting of cardiac failure and can be used successfully after pediatric OHT for primary graft dysfunction or rejection.

Prenatal Exposure to Methyldopa Leading to Hypertensive Crisis and Cardiac Failure in a Neonate

A 2-week-old infant with normal intracardiac anatomy presented to the emergency department in a hypertensive crisis with acute cardiac failure. Despite extensive evaluation, no underlying disease was found. The patient’s hypertension and cardiac dysfunction resolved after 1 week of supportive care in the PICU, and she was discharged within 2 weeks of presentation. The patient’s history revealed transplacental exposure to the α-adrenergic agonist methyldopa for 10 weeks before delivery. Her age at presentation and the self-limited nature of cardiac sequelae with complete resolution of cardiac dysfunction suggest withdrawal effects from this exposure. Whereas the rebound hypertensive effects of α-adrenergic agonists are well established in the adult population, this report shows an unusual adverse outcome of in utero exposure to methyldopa.

Outcomes of Berlin Heart EXCOR® pediatric ventricular assist device support in patients with restrictive and hypertrophic cardiomyopathy

The outcomes of pediatric ventricular assist device support in patients with diastolic heart failure have not been well described. This study reviews the North American experience with Berlin Heart EXCOR® ventricular assist device implants in children with such physiology. The Berlin Heart clinical database was reviewed. Patients with primary diastolic dysfunction are included in this study. Twenty pediatric patients with restrictive cardiomyopathy (n = 13), hypertrophic cardiomyopathy (n = 3), or congenital heart disease with restrictive physiology (n = 4) who were supported with EXCOR® were identified. Of these, nine (45%) were successfully bridged to transplant, one (5%) weaned from support, and 10 (50%) died after support was withdrawn. Of patients under age 3 years (n = 13), 38.5% survived, whereas those aged 3 or older (n = 7) had 71.4% survival (P = .35). Biventricular assist device (BiVAD) patients experienced a 27.3% survival, vs 77.8% for patients with left ventricular assist device only (P = .07). Primary causes of death included stroke, infection, acidosis, multisystem organ failure, and bleeding. Pediatric patients with diastolic heart failure comprise a high‐risk population for mechanical circulatory support. However, half of patients with this physiology have been successfully supported to explant with EXCOR®. The trends toward higher mortality for younger patients and those receiving BiVAD support warrant consideration.

Unguarded mitral orifice associated with hypoplastic left heart syndrome

In the spectrum of mitral valve anomalies, unguarded mitral orifice is an exceedingly rare malformation, with only four cases described in the current literature. All previously reported cases have been associated with discordant atrioventricular connections. We describe the first known case of unguarded mitral valve orifice, in the setting of atrioventricular concordance, in a newborn with hypoplastic left heart syndrome.

Postoperative Serum Troponin Trends in Infants Undergoing Cardiac Surgery

Troponin-I (TN-I) levels are elevated following pediatric cardiac surgery with speculation that particular patterns may have prognostic significance. There is lack of procedure-specific data regarding postoperative TN-I levels in infants undergoing cardiac surgery. We hypothesized that TN-I elevation varies with type of surgery and persistent elevation predicts poor prognosis. We prospectively measured serial TN-I levels (preoperatively, 4, 8, 12, 24, and 48 hours postoperatively) in 90 infants (age < 1 year) undergoing cardiac surgery: off cardiopulmonary bypass (CPB) (n = 15), on CPB (n = 43), and on CPB with ventricular incision (CPB with ventricular incision; n = 32). All patients had undetectable baseline TN-I levels. The area under the curve of TN-I levels over the 48-hour period was significantly different among the surgical groups (P < 0.002), and highest in patients with CPB with ventricular incision. Generally, TN-I levels peaked by 4 hours after surgery and returned to near-normal levels within 48 hours. A persistent TN-I rise beyond 8 hours after surgery was a strong predictor of postoperative hypoperfusion injury (defined as a composite endpoint of end-organ injury resulting from inadequate perfusion, odds ratio 21.5; P = 0.001) and mortality (30% in those with persistently high TN-I, compared with 3.5% in the remaining patients; P < 0.001), independent of patient age, anatomy and/or complexity of surgery, and level of postoperative support. Our data provide benchmark values for TN-I levels following cardiac surgery in infants. Extent of TN-I elevation correlates with type of surgery. Persistent TN-I elevation beyond 8 hours after surgery is strongly associated with postoperative hypoperfusion injury and mortality.

Exercise capacity following pediatric heart transplantation: A systematic review

Pediatric HTs account for 13% of all HTs with >60% of recipients surviving at least 10 years post‐HT. The purpose of this systematic review is to synthesize the literature on exercise capacity of pediatric HT recipients to improve understanding of the mechanisms that may explain the decreased exercise capacity. Six databases were searched for studies that compared the exercise capacity of HT recipients ≤21 years old with a control group or normative data. Sixteen studies were included. Pediatric HT recipients, as compared to controls or normative data, exhibit significantly higher resting HR, and at peak exercise exhibit significantly decreased HR, VO2, power, work, minute ventilation, and exercise duration. Peak VO2 appears to improve within the first 2.5 years post‐HT; peak work remains constant; and there is inconclusive evidence that peak HR, HR recovery, and HR reserve improve with time since HT. These results are discussed in the context of the mechanisms that may explain the impaired exercise capacity of pediatric HT recipients, including chronotropic incompetence, graft dysfunction, side effects of immunosuppression therapy, and deconditioning. In addition, the limited literature on rehabilitation after pediatric HT is summarized.