Congenital heart disease and anesthesia-related cardiac arrest: connecting the dots.

In this issue of Anesthesia & Analgesia, Ramamoorthy et al. report results from the Pediatric Perioperative Cardiac Arrest (POCA) Registry over an 11-year period from 1994 to 2005. The primary goal of this analysis was to compare reports of anesthesia-related cardiac arrest (CA) in children with underlying heart disease (HD) with those who did not have a preexisting cardiac condition. In summary, the authors found that 34% of reported CAs occurred in patients with congenital or acquired HD, more than half of whom (54%) were undergoing noncardiac procedures in the general operating room (OR). The most common cardiac diagnosis category comprised anatomic constellations resulting in a single ventricle. The overall mortality after CA was higher in children with HD (33% vs 23% in patients without HD), although this difference disappeared when corrected for ASA physical status. Before expounding on the implications of this study, it is important to understand the limitations of the data, as the authors acknowledge. The POCA Registry is comprised of voluntary reports from a varying number (58–79) of institutions, 72% of which are university-affiliated hospitals. The reports are anonymous, not independently validated for completeness and accuracy, and no denominator data are available for comparative statistics. In addition, given this collection method, it is almost certain that the numerator reflects underreporting and perhaps even disproportionate reporting of patients with or without HD. The authors also appropriately question whether data derived largely from university-affiliated children’s hospitals can be extrapolated across the vast range of settings in which children may undergo procedures. Despite all these stipulations, this study does make an important contribution to our understanding of the unique vulnerability of children with congenital HD in the perioperative setting. Taken in conjunction with prior studies on this topic, the following 3 important questions emerge. 1. Are Pediatric HD Patients at Greater Risk for CA in the Noncardiac Procedure Setting Compared with Patients without HD? Although the limitations of the POCA study do not permit an indisputable answer, there is support for this inference. Although the authors suggest that the larger number of CA reports emanating from the general OR may reflect a greater number of procedures performed on patients with HD in that setting, other data do not support that hypothesis. At the Children’s Hospital of Philadelphia, only 18% of the procedures that children with HD undergo occur in the general ORs, and if other POCA Registry institutions have a similar distribution in this population, the fact that 54% of CAs occur in this venue suggests greater risk. Moreover, HD patients are only 2.3% of the general OR case volume at Children’s Hospital of Philadelphia. In a large study of 191,261 noncardiac pediatric operations over 4 years in the University Hospital Consortium, Baum et al. reported that 3.1% had a diagnosis of congenital HD. The POCA Registry reveals that 22% of the reported CAs in general ORs are patients with HD, representing a disproportionate share in relation to their prevalence. This figure coincides with the findings from a comprehensive quality assurance database at the Mayo Clinic that captured 92,881 pediatric anesthetic cases over 17 years. Children with HD accounted for 56% of the reported CAs in both cardiac and noncardiac operations, although most were not considered anesthesia related. In the general OR, 27% of the CA patients had HD. Thus, there is rather compelling data that children with HD face greater risk of CA in the general OR setting compared with those without HD. Although there is some suggestion that HD patients confront greater risk of anesthesia-related CA in the general OR than the cardiac OR, that comparison requires assumptions about case classification and reporting that may not be appropriate.