Decreased Mortality after Total Arch Replacement with Frozen Elephant Trunk in Acute Type A Aortic Dissection: An Analysis of the STS Database

Purpose: Total aortic arch replacement (TAR) with Frozen Elephant Trunk (FET) is an effective surgical option for Acute Stanford Type A aortic dissection (TAAD) with dissection flap beyond zone 2. Concerns of increased complications remain after adding FET to the TAR; warranting comparison of TAR with FET versus TAR alone.

Methods: From January 2017 to December 2020, patients who had treatment for acute TAAD were queried via the Society of Thoracic Surgeons (STS) database (N=18706). All patients with distal extent greater than zone 2 were included. Those with missing data or previous cardiac operations were excluded.
In total, 4066 eligible records were found. We excluded 1322 as they did not undergo arch repair leaving 2744 patients. Of those who had arch repair, those who underwent Hemi-arch repair ± FET (n=2507) were excluded and only those who underwent TAR ± FET (n= 237) were analyzed. Demographic, intraoperative, and post-operative data were analyzed using descriptive statistics. To minimize bias associated with baseline characteristics between those who did and did not undergo FET we utilized multiple regression to calculate risk adjusted odds ratio adjusted for age, sex, race, high volume center, and preoperative malperfusion.

Results: Our final cohort consisted of 237 patients. Of those (n=77) underwent TAR and (n=196) underwent TAR with FET. Baseline characteristics (Table 1) showed statistically significant differences in race and preoperative malperfusion higher in the TAR+FET group. Intraoperatively, there was a difference in arterial cannulation site and an increase in unplanned aortic valve replacement in the TAR with FET group. There was, however, no significant difference in cardiopulmonary bypass time and circulatory arrest time. Those who underwent TAR with FET had significantly lower 30-day mortality (OR=0.455 p=0.019) while having similar length of stay and ICU time. Although not statistically significant, there was a trend towards fewer 30-day readmissions in the TAR with FET cohort. There was no significant difference in complications: new renal failure, liver dysfunction, stroke, and spinal cord ischemia. After adjusting for multiple potential confounders, 30-day mortality remained significantly lower in those who underwent TAR with FET (OR=0.49 CI= 0.25 to 0.98) despite more of those in this group presenting with malperfusion. Our risk adjusted logistical regression found that presentation with signs of malperfusion, and presentation at a lower-volume center (fewer than 30 cases per year) were shown to be significant factors for higher mortality within our model.

Conclusion: Total Arch Replacement with FET is associated with reduced early mortality compared to TAR alone in those presenting with greater than zone 2 TAAD. With the theoretical benefits of decreased reintervention and promoting aortic remodeling, FET may be ideal for those presenting with TAAD, especially with clinical malperfusion.

Identify the source of the funding for this research project: Internal funding