Is Time on our Side? The Influence of Time Span between Initial and Redo Cardiac Surgery on Pericardial Adhesions, Preparation Time, and Postoperative Outcome after Reoperation

Background: Reoperative cardiac surgeries comprise a constant portion of the current cardiac surgical practice constituting 8 to 9% of all cardiac surgical procedures in Germany and may be associated with increased risk of perioperative injury and operation time due to pericardial adhesions to greater or lesser extent. Some cardiac surgeons express the suspicion that the severity of these adhesions decreases with increasing time interval between the primary sternotomy the sternal reentry (interval time). We aimed to objectify these assumptions by determining the influence of interval time on redo operative parameters and outcome.

Method: The period from skin incision to bypass start (preparation time) was considered as a predictor for the severity of the pericardial adhesions. We retrospectively analyzed 516 patients who underwent both primary and redo cardiac surgery with cardiopulmonary bypass at our institution between August 2008 and December 2020. Seventeen surgeons were involved in different types of operations. Preparation time and perioperative outcomes were reviewed for each pair of operations and interval time between the two interventions was calculated. The core of data analysis comprised a polynomial linear regression analysis using a mixed model estimation to adjust for confounding factors affecting operative times in redo surgery as surgeon or closure of pericardium in the initial operation.

Results: Preparation time, overall operative time, cross-clamp time, and bypass time were significantly longer in redo operations. The dependency of the preparation time upon the interval time demonstrated an inverted-U line with its maximum at 79.3 months. This relation was consistent among all surgeons, but failed statistical significance (p = 0.092). The surgeon performing the redo operation had the most significant effect on the preparation time (p < 0.01). The mixed model revealed a significant correlation between interval time, preparation time, and 30-day mortality after reoperation (p < 0.05).

Conclusion: Redo cardiac surgery bears substantial risk of reentry injury due to pericardial adhesions. Some surgeons suggest that severity of scarring decreases with increasing time span between the operations, leading to easier and faster preparation during repeat sternotomy. In our study, all surgeons needed maximum preparation time of approximately 8-year-time interval between operations. Decreasing preparation times after that time point might confirm the initial assumption, but failed statistical significance. Longer time span between operations reduced the risk of in-hospital mortality in redo operations.

Publication History

Article published online:
28 January 2023