Repair of total anomalous pulmonary venous connection: risk factors for postoperative obstruction.

White BR, Ho DY, Faerber JA, Katcoff H, Glatz AC, Mascio CE, Stephens P Jr, Cohen MS.

Ann Thorac Surg. 2019 Mar 15. pii: S0003-4975(19)30354-6. doi: 10.1016/j.athoracsur.2019.02.017. [Epub ahead of print]

PMID: 30885849

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Take Home Points:

 

  • Patients born with total anomalous pulmonary venous return have a high risk of recurrent obstruction post-repair though there is still a question of which patients are at highest risk.
  • This retrospective, single-center study evaluated their experience with TAPVR repair and sought to identify risk factors for postoperative pulmonary venous obstruction as well as to try to standardize (and risk stratify) the preoperative echo findings for postoperative obstruction.

Commentary from Dr. Timothy Pirolli (Dallas), section editor of Congenital Heart Surgery Journal Watch:  For patients born with total anomalous pulmonary venous return (TAPVR), surgical repair involving creating an unobstructed connection between the venous confluence and the left atrium is the only viable option. Despite an optimal repair, some patients still develop postoperative venous obstruction, which may be untreatable and lead to death. There is no definitive consensus on how to define either pre- or post-operative pulmonary venous obstruction and the risk factors for post-operative obstruction are unclear. The authors of this study sought to better delineate the preoperative and operative risk factors for postoperative obstruction by reviewing a large cohort of TAPVR repairs at their center (Children’s Hospital of Philadelphia). The authors also sought to examine what degree of preoperative obstruction might be predictive of outcome and to create an echo grading system for obstruction.

 

They looked at all babies undergoing TAPVR repair between January 2006 and October 2017 and found 119 patients. This cohort included patients who had single ventricles and also patients undergoing concurrent cardiac surgical repairs. Notable findings included a whopping 39.5% of patients had single ventricle and 53.8% of all patients had some degree of obstruction. The authors developed definitions for obstruction grade.  “Trivial” obstruction was defined as a mention of obstruction in the echo report but with a Doppler velocity of  < 1.2 m/s. Mild obstruction was defined as a Doppler velocity of ≥ 1.2 m/s but < 2 m/s. Moderate obstruction was defined as Doppler velocity of ≥ 2 m/s, a cath gradient of ≥ 4 mmHg or clinically-noted respiratory distress requiring urgent surgery. Severe obstruction was defined as need for immediate postnatal surgical intervention or stenosis of the vertical vein requiring stenting in cath lab. See Table 1 below for the baseline characteristics of all patients.

 

The primary endpoint was postoperative obstruction analyzed in a survival framework. Postoperative obstruction was defined as a Doppler velocity of ≥ 1.2 m/s in either the confluence or an individual pulmonary vein or a cath gradient of ≥ 4 mmHg from a pulmonary vein to the atrium. The patients were followed and a flowchart of their results is found in Figure 1. Overall only 21% patients met the criteria for postoperative obstruction, with most of these occurring within the first 6 months after the repair (Figure 2). Interestingly, no postoperative obstruction was identified later than 2.1 years after surgery. The authors also examined if the type of TAPVR affected likelihood of survival without postoperative obstruction and showed the “mixed” type was the highest risk (Figure 3). They also found that heterotaxy syndrome and single ventricles were at higher risk for postoperative obstruction (Figure 4). Finally, in Figure 5, using their preoperative definitions of grades of obstruction, they found using cut-offs of trivial or mild obstruction increased the risk of postoperative obstruction significantly. Other factors such as gestational age, genetic syndrome, type of surgical repair (direct vs. “sutureless”), and whether or not the vertical vein was ligated did not show any statistically significant differences in postoperative obstruction.

 

This is a thorough review of the recent TAPVR experience at CHOP and contributes very useful information into how to counsel families and manage this challenging anomaly. The development of a preoperative (and postoperative) grading system for pulmonary venous obstruction is certainly helpful and seems to correlate with their outcomes nicely. The findings of association of single ventricle, heterotaxy and mixed-type TAPVR are not newsworthy, but the lack of associations of early age at surgery, genetic syndrome, and surgical technique (among other factors), is helpful. The study suffers from the same limitations as the majority of single-center, retrospective reports; however this was more than just your standard “show-and-tell” retrospective study.  The relatively common (and often lethal) morbidity of postoperative pulmonary vein stenosis has persisted despite advances in diagnosis, surgical technique and post-operative management. This report should help cardiologists and surgeons standardize the risk stratification for patients cursed with this high-risk anatomical arrangement.

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