Identifying Subclinical Coronary Abnormalities and Silent Myocardial Ischemia After Arterial Switch Operation.

The incidence of late coronary complications is reported around 8% after arterial switch operation (ASO) for d-transposition of the great arteries, but the affected patients are usually asymptomatic. Exercise stress test (EST) and myocardial perfusion imaging (MPI) are common non-invasive modalities to screen for silent myocardial ischemia, but their diagnostic reliability in children after ASO is unclear. We retrospectively reviewed asymptomatic patients following ASO with EST, MPI, and coronary imaging studies (CIS) and examined the reliability of each test in identifying abnormal coronary lesions responsible for myocardial ischemia. Thirty-seven asymptomatic patients (24 males; ages 12.7 ± 3.7 years) had EST, in which 27 and 33 patients also underwent MPI and CIS, respectively. Exercise capacity was comparable to the age- and sex-matched 37 controls. In seven patients with angiographically proven moderate to severe coronary abnormalities, only two patients had positive EST and/or MPI, and five patients were negative including one patient who later developed exercise-induced cardiac arrest due to severe proximal left coronary artery stenosis. Two patients with positive EST or MPI showed no corresponding coronary abnormalities by CIS. Occurrence of acquired late coronary abnormalities did not correlate with the original coronary anatomy or initial surgical procedures. There is no single reliable method to identify the risk of myocardial ischemia after ASO. Although CIS are regarded as a gold standard, multidisciplinary studies are essential to risk-stratify the potential life-threatening coronary lesions after ASO in children.

Use of insulin to decrease septic shock-induced myocardial depression in a porcine model.

Insulin is known to attenuate septic shock-induced myocardial depression. Possible mechanisms include an anti-inflammatory or inotropic effect of insulin. The objective of this study was to determine whether the mechanism of action of insulin in attenuating septic shock-induced myocardial depression is through an immunomodulatory effect. Fourteen pigs were assigned to one of two groups. Both groups received a 4-h infusion of lipopolysaccharide endotoxin from Escherichia coli 0111:B4. Group 2 additionally received insulin at 1.5 U/kg/h with infusions of D50 normal saline and KCl to maintain normal serum glucose and potassium levels. Cardiac function was measured with shortening fraction using transthoracic echocardiogram. Plasma TNF-α, IL-1ß, and IL-6 levels were obtained every 30 min. Postmortem cytokine analysis and histomorphology were performed on the heart tissue. Although insulin attenuated septic shock-induced myocardial depression, this was not due to an anti-inflammatory effect and, therefore, likely resulted from an inotropic effect of insulin.

Outcome after two-patch repair of complete common atrioventricular canal defects in patients weighing four kilograms or less.

BACKGROUND: Early repair of a complete common atrioventricular canal defect (CCAVCD) may benefit patients who exhibit congestive heart failure and failure to thrive. However, concern about increased risk and fragility of valve tissue has commonly led to delaying the surgical repair until the patients achieve a predetermined weight. We report our experience with a strategy of early repair independent of age or weight. METHODS: Between 2003 and 2009, 32 patients underwent two-patch repair of CCAVCD at our institution; 22 patients weighed between 2.5 and 4 kg (group #1) and 10 weighed more than 4 kg (group #2). Medical records and echocardiographic studies were reviewed to determine whether there was a difference in the incidence of mortality, rate of reintervention, and complications between the two groups. RESULTS: Operative mortality was 3.1% (1 of 32), with one additional death two years after repair, for an overall mortality of 6.25%. Median duration of mechanical ventilation, median hospital stay, and intropic score was similar between both groups. Freedom from valve reintervention was 91% in group #1 (20 of 22), and 89% in group #2 (8 of 9, p = 1.00). CONCLUSIONS: Complete common atrioventricular canal defect can be repaired safely and effectively in patients under 4 kg. Although mortality was not increased, smaller patients have a tendency for longer intensive care and hospital stay as well as a higher incidence of atrioventricular valve regurgitation. However, valve function improved during the period of follow-up and did not impact the freedom from reintervention.