Lahiri S, Wang Y, Caldarone CA, Morris SA.
Pediatr Cardiol. 2019 Nov 22. doi: 10.1007/s00246-019-02224-x. [Epub ahead of print]
Select Item 31755375
Take Home Points:
- For uncommon congenital heart defects, centers with a higher surgical volume have been associated with lower surgical mortality rates than centers with lower volume.
- This review of the Texas Inpatient Use Data File demonstrated an association between higher institutional surgical volume and improved survival after TAPVR repair.
Commentary from Dr. Timothy Pirolli (Dallas), section editor of Congenital Heart Surgery Journal Watch: There have been many studies that support the association with higher surgical volume and improved outcomes. This is especially true in congenital heart surgery where the diversity of lesions is immense and the rarity of specific lesions can be dramatic. One such rare lesion that can have a high mortality is total anomalous pulmonary venous return (TAPVR), which occurs in approximately 1 in 10,000 live births. Repair of isolated TAPVR can be challenging enough, with many patients developing post-repair pulmonary venous stenosis, among other potential complications. Additionally, TAPVR may be associated with other congenital heart defects, single ventricle physiology and heterotaxy syndrome, all of which can increase their postoperative mortality risk.
The authors of this study sought to use the Texas Inpatient Public Use Data File to examine 18 years’ worth of data from state-licensed hospitals that have performed repair of TAPVR. All patients under 1 year old who were hospitalized with the diagnosis of TAPVR were identified from this database. Patient characteristics were identified as were associated congenital heart defects, single ventricle physiology and heterotaxy syndrome. The study examined the overall mortality trend of TAPVR repair in Texas during the study as well as breaking the trend down into separate groups (isolated TAPVR, associated congenital heart defects (CHD), heterotaxy syndrome and single ventricle). The authors also used a multivariable analysis to assess the effect of institutional volume for the procedure with the effects on mortality rate. Their hypothesis was that centers with a higher volume would have a lower mortality.
Out of 7.5 million admissions of children < 1 year old, a total of 971 patients underwent TAPVR repair that met the study requirements. The surgical volume by center (total of 16 centers) is shown in figure 2 below, with a range of 1 repair to 222 repairs during the 18 year period. Overall, mortality for TAPVR repair derived from mixed regression modelling decreased from 15.1% at the start of the study period to 7.6% by the end. Using univariate analysis, the authors found that year of surgery, preterm birth, lower institutional volume, heterotaxy syndrome and presence of additional CHD were associated with higher mortality. With their multivariate analysis, they found that the odds ratio for every increase in 10 patients = 0.93, supporting that higher volume centers had better survival rates.
The study also examined the different subgroups of TAPVR. Repair of isolated TAPVR was the most common surgery with lowest mortality rate (Figure 5). Repair of TAPVR with heterotaxy syndrome and single ventricles are showed in figures 7 and 8, respectively, are shown below. In almost all the multivariable sub-analyses, early year and lower institutional surgical volume were associated with worse outcomes. Of note, the TAPVR/single ventricle group did not have a significant association with lower mortality in later years. I encourage the reader to review the primary study to fully appreciate the scope of data collection and analysis it encompasses.
The study appears to be the first of its kind to demonstrate an association with surgical volume with mortality after TAPVR repair. The authors emphasize that they did not observe a plateau for the mortality rate and that some low- and medium-volume centers had low mortality. The study was restricted to the state of Texas, which is large, but not necessarily reflective of national trends. The emphasis of increased surgical volume on surgical expertise and post-operative care is intrinsic to these findings. The finding of no improved outcomes of single ventricle/TAPVR repairs due to higher institutional volume reflects the high-risk nature of this subgroup of patients. Despite the study analyzing many factors from a “bird’s eye view” of this dataset, there are many details of this lesion that affect outcomes (i.e. type of TAPVR, presence of pulmonary venous obstruction, etc.) that would have made the analysis of these findings all the stronger. It would also be interesting to see how many patients were transferred from another center that performs TAPVR repair to a higher volume center. These types of factors were unavailable as the data is from an administrative database that does not capture as many medical and surgical details of each patient as other databases (i.e. the STS database).
The study is strong, but obviously has limitations. The institutions are not identified and there is no sense of which surgeons are performing the surgeons, so the study does not completely guide practitioners to which institution to direct their TAPVR patients’ care (though, those of us in Texas have some ideas!). Texas has just under 9% of the total population of the United States, and the study acts as a strong sampling of what national trends may be. Of course, the demographics of Texas are not the same as Delaware, and there could be genetic or environmental factors that could affect the prevalence of TAPVR and associated lesions. So it is unclear how easily this data can be applied to other areas. It is retrospective and does not offer sufficient details about all pertinent risk factors, etc. Overall, though, the study offers a fascinating glimpse into the trends in TAPVR repair over time in the second largest state in the county.
Tables and Figures