Reoperative aortic root surgery: single-center long-term outcomes and literature review

Introduction

Surgical treatment of aortic root pathologies improved significantly over the last 20 years. Better perioperative management and surgical technique led to reduced mortality, and better long-term outcomes (1,2). The latest report based on the Society of Thoracic Surgeons (STS) database showed a 2.2% operative mortality for elective aortic root replacement (3). However, redo aortic surgery in general is still a high-risk cardiac procedure, with a reported surgical mortality of 6–16% (4-6). The main indications are illustrated in Table 1. Reoperations on the aortic root have increased due to the aging of the population, the growing use of biological conduits and the increase of reparative aortic root operations. Furthermore, prosthetic valve endocarditis and pseudoaneurysms are indications for aortic root reoperations. Although aortic root surgery yields excellent results as a primary procedure, reoperations, especially if root surgery was performed during the first procedure, are still challenging and result in a higher mortality rate.

The purpose of this article was to collect and critically review the literature on aortic root redo to evaluate the main challenges of this type of surgery. We also aim to describe our center’s experience in aortic root redo surgery. We present this article in accordance with the Narrative Review reporting checklist (available at https://jtd.amegroups.com/article/view/10.21037/jtd-23-1629/rc).

Methods

Literature search criteria

The initial search was performed using PubMed databaseselecting publications in English, with no time restrictions. A further selection was achieved by filtering literature using ‘aortic root redo’ OR ‘redo operation on aortic root’ OR ‘aortic root replacement after previous surgical intervention’ as either keywords or MeSH terms. Studies with a population of less than 20 patients were not considered. When more than one article describing the experience of a single center was found, only the most recent one was considered. The search strategy for the review is summarized in Table 2 and in the flowchart provided in Figure S1. No protocol is available for this scoping review.

Data extraction and appraisal

All data was extracted from article text and tables. All values are represented as numbers (percentages), mean ± standard deviation or median. Freedom from further aortic reintervention has been analyzed by using Kaplan-Meier method. This retrospective study was approved by local institutional review board (G.D.G., D.P-10/2023), and did not require patients’ informed consent.

Surgical technique

The surgical strategy must be carefully planned: the main concern is to assess a safe re-entry, a proper cannulation and, if needed, cerebral protection strategy. Chest re-sternotomy is a critical moment of the procedure, and a preoperative computed tomography (CT) scan is recommended to measure the distance between the sternum and ascending aorta (or right ventricle) and to plan a safe re-entry (7).

In re-entries, our standard approach includes complete removal of the steel wires and the use of the oscillating saw. Before re-sternotomy, patient should be in anti-trendelemburg position in order to reduce the heart’s filling and systolic blood pressure should be lowered under 100 mmHg. Moreover, we always prepare arterial and venous lines on the surgical field, ready for emergency cannulation: in selected high-risk patients, surgical isolation of peripheral cannulation sites could be performed before re-sternotomy.

Selection of cannulation sites has changed over the years: the employment of the femoral artery has been reduced in favor of central cannulation sites, such as the ascending aorta, aortic arch, and right axillary or innominate artery. In recent years this trend has been validated by literature, as central cannulation in redo surgery has been associated with better postoperative outcomes (8). In accordance with this, when possible, we prefer to cannulate the right axillary and the innominate artery when an arch reconstruction is also required and the ascending aorta or the aortic arch when only root procedures are planned. However, in patients with difficult re-opening at preoperative imaging, we choose to cannulate right axillary or the femoral artery. In extremely complicated re-entries or in an emergent setting cardiopulmonary bypass (CPB) may be started before or during sternotomy. This should only be considered in selected cases and it has become rarer over the years.

If coronary artery bypass grafting was performed during the first surgery, mobilization of the coronary arteries and of patent graft should be performed carefully and can be made difficult by the presence of scarring (9).

Surgical technique depends on location of the aortic disease: in case of aortic root involvement, we can choose among different options.

The first choice is the Modified Bentall procedure with the coronary ostia reimplantation. Dissecting out the coronary buttons is the critical part of the operation, and difficulty is frequently due to the presence of felt and biologic glue. In case of reintervention on previous Bentall or in case of a massive pathology involving the coronary ostia, the Cabrol technique could be a valid alternative (10).

Results

Literature review

We analyzed experiences from multiple centers with aortic root redo operations. Tables 3-5 summarize the most relevant studies on the matter of redo aortic surgery. We chose to analyze 12 studies (11-22). Most were single center, retrospective. One was a multicentric retrospective study based on inquiry of the STS database on the population of the USA. A total population of 16,627 patients across 12 studies was depicted in our analysis. The mean age was 57 years.

Indications for aortic root redo surgery are usually represented by progression of aortic disease (aneurysm or dissection), prosthesis valve or aortic conduit dysfunction or infective complications after previous surgery. Endocarditis was the indication for surgery in a total of 5,901 (35.5%) of patients (Table 3).

At the time of redo surgery, a Bentall procedure was performed in most cases (90%), while valve-sparing or prosthesis sparing techniques were much less common (4%). Though very variable across the studies, mean cardio-pulmonary bypass and cross-clamp times were 218 and 152 minutes, respectively (Table 4).

Postoperative results are represented in Table 5. The reported in-hospital or 30-day mortality was 12%. Long-term follow-up was not available in all studies as some of them focused on short-term results.

Results in Bologna

Since the early 2000s, we acquired a wide experience in redo surgery both for proximal and distal aortic disease (16,20,21). We observed a progressive increase in the frequency of thoracic aorta reoperations through the decades (20). A total of 344 aortic root redo operations were performed at our center from January 1986 to December 2022. Indications for redo surgery were mostly related to the progression of aortic root dilatation (n=127, 36.9%), chronic or residual dissections after a previous type A dissection repair (n=89, 25.9%), endocarditis (n=65, 18.9%), pseudoaneurysm (n=40, 11.6%), acute aortic syndrome (n=11, 3.2%) and prosthesis dysfunction (n=12, 3.5%). First interventions were mostly aortic valve replacement, either isolated (n=137, 39.8%) or paired with ascending aorta replacement (n=26, 7.6%). Others were Bentall operation (n=59, 17.2%), aortic valve repair associated with procedures on the root and ascending aorta (n=21, 6.1%), ascending aorta and arch replacement (n=84, 24.4%) and other cardiac procedures (n=17, 4.9%). The mean age of our population was 58.9±13.2 years, the majority of patients were male (78.8%). Among the considered surgeries, 16% were performed as urgent. At reoperation, 162 patients (47.1%) underwent a Bentall procedure, 104 (30.2%) also received arch replacement, valve-sparing root replacement was done in 7 patients (2%) and prosthesis sparing root replacement was performed in 59 cases (17.2%). Mean CPB and cross-clamp times were 218.0±78.8 and 158.2±49.7 minutes, respectively. Pre- and intraoperative characteristics of our population are depicted in Table 6. Overall, in-hospital mortality was 9.6% (including patients who underwent arch replacement). When considering only patients in which arch surgery was not performed, in-hospital mortality declined to 6.7%. Mortality was significantly higher when endocarditis was the indication (16.9%). Intensive care unit (ICU) stay was 5.1±8.2 days. Mean follow-up time was 52.3±41 months. Survival was 76.1% after 5 years and 51.4% after 15 years (Figure 1). Further aortic reinterventions were performed in 41 patients. The most frequent procedure at follow-up was TEVAR (n=20, 48.8%), followed by Bentall (n=8, 19.5%), arch replacement (n=5, 12.2%), pseudoaneurysm repair (n=5, 12.2%) and hemiarch replacement (n=3, 0.7%). Freedom from aortic redo of was 88.1% after 5 and 64.9% after 15 years (Figure 2). Causes of death at follow-up were cardiac/aortic death (15, 19.7%), neurological (12, 15.8%), septic shock (6, 7.9%), cancer (8, 10.5%), endocarditis (2, 2.6%), multi-organ failure (1, 1.3%) and unknown (32, 42.1%).

Figure 1 Survival at follow-up after redo aortic root surgery at our center.

Figure 2 Freedom from further reintervention at follow-up after redo aortic root surgery at our center.

Discussion

Even though aortic root surgery has shown excellent results as a primary procedure, reoperations, especially in patients with previous aortic root surgery, are still challenging (23,24). Since redo aortic root surgery is very complex and needs to be performed in centers with great expertise, only a limited number of studies are available in literature and not all provide long-term results and information on freedom from further reoperation. Regarding indications, endocarditis, degenerative aneurysm progression and residual dissections after replacement of the ascending aorta in acute type A aortic dissection have been reported as the most frequent (25). This is in accordance with both what we found in literature and our own experience. Also, pseudoaneurysms are observed very often: they may involve the aortic annulus, the coronary buttons reattachments, or both. They are more frequently observed in patients with connective tissue disorders or after root replacement in acute aortic dissections (26). Pseudoaneurysms often represent a technical challenge as they can be very large and reach a retrosternal position, rendering reopening particularly tricky. Therefore, they often require a careful and personalized planning for re-entry as some examples in literature show (27,28).

Another frequent etiology is infective endocarditis, which is linked to high postoperative mortality (16) and worse postoperative outcomes (13). Endocarditis might lead to the involvement of the mitro-aortic curtain, presence of abscess or fistula and, in the worst scenario, a complete detachment of a previous aortic prosthesis or conduit. In some of these cases, a reconstruction of the aortic valve annulus might be needed and is often performed at our center using pericardium patches (Figure 3). When the mitro-aortic curtain is involved, with or without mitral valve endocarditis, its reconstruction might be needed requiring a “Commando” operation (29,30).

Figure 3 Intraoperative images during a case of redo root surgery for endocarditis. When endocarditis is the cause, redo surgery may require reconstruction of the aortic “anulus”, often performed with pericardial patch (A). (B) An explanted prosthesis in a patient reoperated for endocarditis.

Failure in coronary reimplantation and unplanned coronary artery bypass graft (CABG) surgery represents a possible complication of this type of reintervention and a significant risk factor for patient mortality (21). In case of well-functioning prosthesis, a valid surgical option is the prosthesis-sparing reoperation first described in 2005, which consist in the replacement of the aortic root leaving aortic prosthesis in place (23,31). In some patients aortic hemiarch or arch replacement is also required, associated with increased risk of mortality and major morbidity.

The data we are here reporting from our experience seems consistent with what emerged from our literature review when considering indications for surgery, CPB and cross-clamp times, population characteristics and postoperative outcomes. Further data on the matter will, however, be necessary in order to clearly identify risk profiles for patients who might have worse outcomes after such complex procedures.

Study limitations

The studies the present literature review is based on are all retrospective. All but one are single-center studies and the only multicentric one, based on the whole available data from the USA STS Database, comprises the vast majority of the patients considered. This means that the sources are very hard to compare both for the highly variable number of patients and for the variables considered and the outcomes that were investigated.

Conclusions

Reoperative aortic root surgery is being performed more and more frequently. Despite its complexity, good outcomes can be achieved with an appropriate surgical approach in high-volume aortic centers. According to our experience, outcomes are significantly worse in infective endocarditis and further redo was not frequently observed at follow-up.

Acknowledgments

Funding: None.

Footnote

Reporting Checklist: The authors have completed the Narrative Review reporting checklist. Available at https://jtd.amegroups.com/article/view/10.21037/jtd-23-1629/rc

Peer Review File: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-23-1629/prf

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jtd.amegroups.com/article/view/10.21037/jtd-23-1629/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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