No abstract

Background-We have previously suggested that the primary arterial switch operation is a feasible strategy for patients with transposition of the great arteries and intact ventricular septum (TGA-IVS) up to age 2 months. This study reports our current results with this approach and examines whether this policy could be extended beyond age 2 months. Methods and Results-380 patients who underwent arterial switch for TGA-IVS were reviewed. 275 patients were younger than 3 weeks at the time of surgery (early switch group); 105 patients were 3 weeks or older (range, 21 to 185 days) (late switch group). There was no difference in outcome in terms of in-hospital mortality (5.5% versus 3.8%) or need for mechanical circulatory support (3.6% versus 5.7%) between early and late switch groups. However, duration of postoperative ventilation (4.9 versus 7.1 days, Pϭ0.012) and length of postoperative stay (12.5 versus 18.9 days, PϽ0.001) were significantly prolonged in the late switch group. Primary left ventricular failure resulting in death occurred in 2 patients in the late switch group, with no deaths in 9 patients aged 2 to 6 months. Conclusions-This experience confirms that in TGA-IVS, the left ventricle maintains the potential for systemic work well beyond the first month of life. Consequently, neonates at high risk or late referrals can benefit from delayed arterial switch, even beyond age 2 months. However, the need for mechanical support in some of the older patients may limit the widespread adoption of such a strategy.

This study identifies age at operation, RACHS-1 risk category and bypass time as highly significant risk factors for mortality after paediatric open-heart surgery. It validates the RACHS-1 risk stratification method as applied to the subset of open-heart surgery, whilst accepting the limitations of such a system. The risk models formulated permit risk prediction and allow for analysis of surgical results. Such risk-adjustment is important when assessing performance and comparing outcomes amongst individuals or institutions.

Aims: Criteria for diagnosing myocardial infarction (MI) after coronary artery bypass grafting (CABG) are controversial. Uncertainties remain around the optimal threshold for biomarker elevation and the need for associated criteria. There are no studies of high-sensitivity troponin (hs-TnT) after CABG. We assessed whether using hs-TnT to define MI after CABG was associated with 30-day and medium-term mortality and evaluated the utility of adding to the troponin criteria new Q-waves or imaging evidence of new wall motion abnormality as suggested in the Universal Definition of MI. Methods: Isolated CABG was performed in 818 patients from July 2010 to June 2012 and hs-TnT was measured 12-24 hours after CABG. Patients with rising baseline or missing troponins (n=258) were excluded. Thresholds of 140 ng/l (10-times 99th percentile upper reference limit) and 500 ng/l (10-times coefficient of variation of 10% for fourthgeneration troponin T applied to hs-TnT) were prespecified. Results: Mean follow up was 1.8±0.6 years. On multivariate analyses, isolated hs-TnT rise >140 ng/l (n=360) or >500 ng/l (n=162) were not associated with mortality. Additional ECG and/or echocardiographic criteria plus hs-TnT >140 ng/l was associated with 30-day mortality (hazard ratio, HR, 4.92, 95% CI 1.34-18.1; p=0.017) and medium-term mortality (HR 3.44, p=0.030), whereas ECG and/or echocardiographic abnormalities with hs-TnT >500 ng/l was not (p=0.281 and p=0.123 for 30-day and medium-term mortality, respectively). Conclusions: A definition for MI following CABG using hs-TnT with a cut point of 10-times 99th percentile upper reference limit and ECG and/or echocardiographic criteria predicts 30-day and medium-term mortality. These findings validate the Third Universal Definition of type 5 MI.