Evaluating Necessity of Azygos Vein Ligation in Primary Repair of Esophageal Atresia

Preservation of the azygos vein versus ligation of the azygos vein during primary surgical repair of congenital esophageal atresia

BACKGROUND

Esophageal atresia is one of the most common life-threatening congenital malformations and is defined as an interruption in the continuity of the esophagus with or without fistula to the trachea or bronchi. Definitive treatment is surgical ligation of the fistula if present and esophageal end-to-end anastomosis of the two pouches, thereby reconstructing the continuity of the esophagus. During this procedure, the surgeon may choose to either ligate or preserve the azygos vein, a major draining vein for the esophagus and surrounding structures, but no definitive consensus on the matter exists.

OBJECTIVES

To assess the benefits and harms of preservation of the azygos vein versus ligation of the azygos vein during primary surgical repair of congenital esophageal atresia.

SEARCH METHODS

We identified trials from the Cochrane Gut Specialized Register, Cochrane Central Register of Controlled Trials (CENTRAL) via Ovid Evidence-Based Medicine Reviews Database (EBMR), MEDLINE, Embase, and CINAHL (Cumulative Index to Nursing and Allied Health Literature). We also conducted a search of ClinicalTrials.gov, LILACS, Science Citation Index Expanded and Conference Proceedings Citation Index - Science (Web of Science), and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). We searched all databases from their inception to 22 May 2024, with no restriction on language of publication.

SELECTION CRITERIA

We included randomized clinical trials (RCTs) assessing preservation of the azygos vein versus ligation of the azygos vein during primary surgical repair of congenital esophageal atresia in infants less than three months of age.

DATA COLLECTION AND ANALYSIS

Pairs of two review authors independently screened titles and abstracts, screened relevant full-text reports, and identified RCTs for inclusion. We recorded the selection process in a PRISMA flow diagram. We assessed the risk of bias of the included studies (using RoB 2) and the certainty of the evidence (using the GRADE approach) according to the Cochrane Handbook for Systematic Reviews of Interventions. We contacted the study authors if data were missing or unclear.

MAIN RESULTS

Six trials met the inclusion criteria, including 390 participants in total. We were able to assess all our primary outcomes: all-cause mortality, serious adverse events, and anastomosis leakage, as well as two of our three secondary outcomes: sepsis or mediastinitis and esophageal stricture. However, none of the six trials assessed recurrent tracheoesophageal fistula. All trials had either some concerns or high risk of bias, and the certainty of the evidence for all outcomes was either low or very low. Meta-analyses showed that preservation of the azygos vein may result in a large reduction in mortality (risk ratio (RR) 0.44, 95% confidence interval (CI) 0.26 to 0.73; low-certainty evidence), serious adverse events (RR 0.33, 95% CI 0.21 to 0.50; very low-certainty evidence), and anastomosis leakage (RR 0.44, 95% CI 0.26 to 0.76; low-certainty evidence) when compared to ligation of the azygos vein in neonates undergoing primary surgical repair of congenital esophageal atresia. Meta-analysis of our secondary outcomes showed that preservation of the azygos vein may result in a large reduction in mediastinitis or sepsis (RR 0.34, 95% CI 0.21 to 0.53; very low-certainty evidence). Esophageal stricture was only reported in two studies with 114 participants. The effects on esophageal stricture were unclear (RR 0.75, 96% CI 0.35 to 1.63; very low-certainty evidence), but the evidence is very uncertain.

AUTHORS' CONCLUSIONS

Current evidence suggests that preserving the azygos vein during primary surgical repair for esophageal atresia may result in large reductions in overall mortality, serious adverse events, anastomosis leakage, and sepsis or mediastinitis. No included data suggested that routine ligation of the azygos vein was beneficial. However, all the evidence was of low to very low certainty. Further research is still warranted as the results of this review may not be applicable to all newborns with congenital esophageal atresia.

Azygos vein preservation revisited: impact on early outcomes after repair of esophageal atresia/tracheoesophageal fistula in newborns

Since the first successful repair of esophageal atresia/tracheoesophageal fistula (EA-TEF) was performed approximately 8 decades ago, surgeons have made considerable technical advances in solving intraoperative surgical challenges and reducing postoperative complications. According to some surgeons, preserving the Azygos vein makes this modification attractive. This study aimed to evaluate the benefits of preserving the Azygos vein during surgery for esophageal atresia with tracheoesophageal fistula and to highlight its advantages in reducing anastomotic leak, stricture, and other postoperative outcomes. This prospective comparative series was conducted between April 2020 and April 2023. The study included all newborns with EA-TEF eligible for primary repair. Patients were randomized to either Group A or B. Group A underwent Azygos vein preservation, whereas the remaining patients (Group B) underwent Azygos vein disconnection. Sixty-four patients were included in this study. Thirty-two patients (Group A) underwent Azygos vein preservation during EA-TEF repair, and the remaining thirty-two patients (Group B) underwent Azygos vein ligation and disconnection. Both groups were comparable in terms of demographics, clinical data, and operative findings (P > 0.05). Pneumonitis occurred in 4 patients in Group A and 16 patients in Group B. Anastomotic leaks occurred in two (6.2%) patients in Group A and six (18.7%) patients in Group B. There were two deaths in Group A and six deaths in Group B, with a significant difference between the two groups (P = 0.0485). Preserving the Azygos vein during esophageal atresia repair reduces the occurrence of postoperative pneumonia, leakage, and stenosis, and decreases postoperative mortality. Therefore, we declare that this modification is a significant and valuable addition to the current surgical procedures.

Esophageal Atresia and Tracheoesophageal Fistula: A Retrospective Review from a Tertiary Care Institute

BACKGROUND

A survey of neonates with esophageal atresia and tracheoesophageal fistula (EA ± TEF) to determine additional factors responsible for poor surgical outcomes in our institution where employing an improved standard of care can ameliorate the outcome.

MATERIALS AND METHODS

We carried out a retrospective review of 54 neonates, who underwent surgical repair of EA± TEF over a 5-year period. We collected data regarding the patients' demographics, perioperative findings, records of neonatal intensive care, and ascertained the effects of gender, gestational age, birth weight, age at operation, type of anomaly, coexisting major anomalies, preoperative inotrope therapy, and duration of postoperative ventilation on the surgical outcome.

RESULTS

The mortality rate was 51.9%, out of which, 42.8% of neonates succumbed to ventilator-associated conditions. Age at the time of surgery, gestational age, preoperative inotrope support, presence of coexisting anomalies, and duration of postoperative ventilation were determined as the significant variables predicting mortality(P < 0.05). The area under the Receiver Operating Curve showed the duration of postoperative ventilation as the best indicator of mortality. The Logistic regression model (χ² = 11.204, P = 0.019) with the above-mentioned variables showed that neonates who were operated before 2.5 days and who required <74.5 hours of postoperative ventilation were 3.91 and 48.30 times more likely to survive respectively, than their counterparts.

CONCLUSION

A delay in surgery due to delayed diagnosis and or delayed transportation to tertiary centres and prolonged ventilatory support have an additional detrimental effect on the surgical outcomes of EA ± TEF.

Azygos vein preservation is feasible and beneficial in esophageal atresia with tracheoesophageal fistula: A meta-analysis of randomized controlled trials

BACKGROUND

Esophageal atresia (EA) with tracheoesophageal fistula (TEF) is a common congenital anomaly. It is still unknown whether azygos vein preservation will increase the difficulty or time of operation and reduce the quality of anastomosis. Thus, we conducted this meta-analysis to explore the puzzle.

METHODS

Two researchers independently searched the databases. Randomized controlled trials were included if these studies applied thoracotomy to perform operations and compared the outcomes in patients with EA/TEF between azygos vein preservation groups and azygos vein ligation groups. The Jadad score was used to assess the quality of the included studies. Statistical heterogeneity was evaluated using the I ² value. A fixed or random-effect model was applied regarding the I ² value.

RESULTS

Four studies involving 286 patients were included. The pooled estimates indicated that preservation of the azygos vein decreased the incidence of anatomic leakage with a pooled risk ratio (RR) of 0.54 (95% CI 0.29-0.99, P = 0.05) and mortality with an RR of 0.51 (95% CI 0.29-0.90; P = 0.02). Preservation of the azygos vein might not require a longer operative time than ligation of the azygos vein.

CONCLUSIONS

This research certifies that preservation of the azygos vein is able to reduce the prevalence of anastomotic leakage and mortality.

The effect of azygos vein preservation on postoperative complications after esophageal atresia repair: Results from the Turkish Esophageal Atresia Registry

AIM

Preservation of the azygos vein (AV) maintains normal venous drainage of the mediastinum and decreases postoperative congestion. The modification of esophageal atresia (EA) repair by preserving AV may prevent postoperative complications and may lead to better outcomes. The data from the Turkish Esophageal Atresia Registry (TEAR) were evaluated to define the effect of AV preservation on postoperative complications of patients with EA.

METHODS

Data from TEAR for a period of five years were evaluated. Patients were enrolled into two groups according to the preservation of AV. Patients with divided (DAV) and preserved AV (PAV) were evaluated for demographic and operative features and postoperative complications for the first year of life. The DAV and PAV groups were compared according to the postoperative complications, such as fistula recanalization, symptomatic strictures, anastomotic leaks, total number of esophageal dilatations, and anti-reflux surgery. In addition, respiratory problems, which required treatment, were compared between groups.

RESULTS

Among 502 registered patients; the data from 315 patients with the information of AV ligation were included. The male female ratio of DAV (n = 271) and PAV (n = 44) groups were 150:121 and 21:23, respectively (p > 0.05). The mean body weight, height, gestational age, and associated anomalies were similar in both groups (p > 0.05). The esophageal repair with thoracotomy was significantly higher in DAV group, when compared to the PAV group (p < 0.05). The rates of primary anastomosis and tensioned anastomosis were similar in both groups (p > 0.05). There was no difference between DAV and PAV groups for anastomotic leaks, symptomatic anastomotic strictures, fistula recanalization, and the requirement for anti-reflux surgery (p > 0.05). The rate of respiratory problems, which required treatment, was significantly higher in the DAV group (p < 0.05) CONCLUSION: The data in the TEAR demonstrated that preserving the AV during EA repair led to no significant advantage on postoperative complications, with exception of respiratory problems. AV should be preserved as much as possible to maintain a normal mediastinal anatomy and to avoid respiratory complications.

Impact of preservation of the azygos vein during surgical repair of esophageal atresia-tracheoesophageal fistula (EA-TEF): a systematic review and meta-analysis

Esophageal atresia-tracheoesophageal fistula (EA-TEF) is one of the common congenital anomalies occurring in newborns. Over the last eight decades, various technical modifications have been proposed in the surgical repair of EA-TEF. Preservation of azygos vein is one such modification that has gained considerable attention. However, a consensus statement regarding the superiority of its preservation over its division is lacking. We aim to compare the outcomes of surgery between the two groups of newborns, i.e., those undergoing repair with and without azygos vein preservation, in terms of its complications. The authors systematically searched the databases PubMed, EMBASE, Web of Science, and Scopus through December 2020. The incidence of anastomotic complications and chest infection was compared among the two groups of newborns, i.e., those undergoing surgical repair with (group A) and without azygos vein preservation (group B). Statistical analysis was performed using a fixed-effects model, and pooled risk ratio (RR) and heterogeneity (I²) were calculated. The methodological quality of the studies was assessed using the Downs and Black scale. Six comparative studies, consisting of a total of 671 newborns, were included in the meta-analysis. As compared to group B, newborns belonging to group A showed a significantly lower incidence of pneumonitis in the postoperative period (RR 0.31; 95% CI 0.17-0.57, p = 0.0001). However, no significant difference in the incidence of anastomotic complications including anastomotic leak (RR 0.73; 95% CI 0.48-1.12, p = 0.15) and stricture (RR 0.63; 95% CI 0.36-1.09, p = 0.10) was observed between the two groups. The average Downs and Black scale scores ranged from 20 to 24. The risk of bias was low (n = 1) and moderate (n = 5) in the included studies. Kappa statistics showed a value of 0.902 (p < 0.001), highlighting an almost perfect agreement among the two observers. The present meta-analysis revealed the superiority of surgical repair of EA-TEF performed with preservation of azygos vein in terms of the incidence of postoperative chest infection. However, no significant difference in the occurrence of anastomotic leak and stricture was observed between the two groups. The level of evidence of the published comparative studies is limited. Therefore, well designed, randomized controlled trial utilizing a standardized operative approach on a larger sample-size needs to be conducted for optimal comparison between the two approaches.

A Unique Variation of Azygos System of Veins

Knowledge of variations of azygos and hemiazygos veins is of importance to cardiothoracic surgeons and radiologists during various surgical, radiological, and echography techniques. We report some unique variations of azygos system of veins observed during dissection classes for undergraduate medical students. The azygos vein was formed as usual by the union of right subcostal and ascending lumbar veins. The vein ascended upward and to the left to reach the midline at the level of the 9^th thoracic vertebra. After ascending till 5^th thoracic vertebra, it gradually inclined to the right of midline and terminated by opening into the superior vena cava at the level of the 3^rd thoracic vertebra. There was no major variation in the tributaries of the azygos vein on the right side, except that the right superior intercostal vein crossed behind the azygos vein from right to left and opened into the left side of the azygos vein. Further, two anastomotic veins connected the 10^th, 11^th and 12^th posterior intercostal veins with each other to form two anastomotic circles on the right side of 10^th to 12^th thoracic vertebrae. The hemiazygos vein bifurcated on the left side of the 10^th thoracic vertebra and the two ends opened into the azygos vein at the level of 9^th and 10^th thoracic vertebrae forming a venous circle in front of the 10^th thoracic vertebra. The course of accessory hemiazygos vein was noteworthy. Instead of its classic descending course, the vein ascended upward from the left side of the 8^th thoracic vertebra till the 6^th thoracic vertebra before opening into the azygos vein.