Most High-Intensity Transient Signals Are Not Associated With Specific Surgical Maneuvers.

BACKGROUND: Mortality after congenital heart defect surgery has dropped dramatically in the last few decades. Current research on long-term outcomes has focused on preventing secondary neurological sequelae, for which embolic burden is suspected. In children, little is known of the correlation between specific surgical maneuvers and embolic burden. Transcranial Doppler ultrasound is highly useful for detecting emboli but has not been widely used with infants and children. METHODS: Bilateral middle cerebral artery blood flow was continuously monitored from sternal incision to chest closure in 20 infants undergoing congenital heart defect repair or palliative surgery. Embolus counts for specific maneuvers were recorded using widely accepted criteria for identifying emboli via high-intensity transient signals (HITS). RESULTS: An average of only 13% of all HITS detected during an operation were correlated with any of the surgical maneuvers of interest. The highest mean number of HITS associated with a specific maneuver occurred during cross-clamp removal. Cross-clamp placement also had elevated HITS counts that significantly differed from other maneuvers. CONCLUSIONS: In this study of infants undergoing cardiac surgery with cardiopulmonary bypass, the great majority of HITS detected are not definitively associated with a specific subset of surgical maneuvers. Among the measured maneuvers, removal of the aortic cross-clamp was associated with the greatest occurrence of HITS. Future recommended research efforts include identifying and confirming other sources for emboli and longitudinal outcome studies to determine if limiting embolic burden affects long-term neurological outcomes.

Prevalence and Anatomy of Retroesophageal Major Aortopulmonary Collateral Arteries.

BACKGROUND: Major aortopulmonary collateral arteries (MAPCAs) are the sole source of pulmonary blood flow in patients with pulmonary atresia and absent ductus arteriosus. The anatomy of MAPCAs can be highly variable, both in the number of MAPCAs supplying each lung and the anatomic origin and course of the MAPCAs. This study evaluated the prevalence and anatomy of retroesophageal MAPCAs in patients undergoing repair of pulmonary atresia/ventricular septal defect/MAPCAs. METHODS: This was a concurrent analysis of 68 consecutive patients (March 2013 through October 2015) undergoing a primary surgical procedure for pulmonary atresia/ventricular septal defect/MAPCAs. A detailed analysis of the MAPCA anatomy was made intraoperatively for each patient, including the total number of MAPCAs to each lung and the presence or absence of a retroesophageal course. These data were correlated with the preoperative cardiac catheterization images. RESULTS: A retroesophageal MAPCA was identified during the operation in 45 of the 68 patients (67%), all of which were located on the side opposite the arch. For the 36 patients with a left aortic arch, 77% had a retroesophageal MAPCA compared with 53% of patients with a right arch. Forty-six percent of retroesophageal MAPCAs coursed within the muscular fibers of the esophagus (intraesophageal) and were more common to the left lung than the right (72% vs 32%). A midsegment stenosis was present in 84% of the retroesophageal MAPCAs, and this was more severe when the MAPCAs were intraesophageal than when they were not (80% vs 42%). CONCLUSIONS: These data demonstrate that two-thirds of patients had a retroesophageal MAPCA and that there were significant differences in prevalence and anatomy depending on the side of the aortic arch. These data provide important insights into the origin and course of retroesophageal MAPCAs.