Tricuspid valve replacement (TVR) is one of the least common procedures in cardiac surgery, posing challenges not only due to its rarity but also because of certain procedural difficulties. Traditionally, it has been reserved for patients with high surgical risk, a topic previously discussed in other blog posts. Additionally, TVR is associated with a high incidence of conduction disorders, carrying a considerable risk of requiring permanent postoperative pacemaker implantation, estimated between 22-32%. This raises the question of whether a preventive, simultaneous pacemaker implantation could be beneficial, thus proactively addressing conduction complications. 

A recent article by a French team from Bichat Claude Bernard Hospital in Paris discusses the prophylactic implantation of a permanent epicardial pacemaker in TVR cases. At this center, routine use of this approach was adopted due to the high incidence of conduction disorders requiring stimulation, not only in the immediate postoperative period but also in the long term. Their objective was to assess the risks and benefits of this practice, as well as identify factors associated with conduction disorders following TVR. A total of 80 patients who underwent TVR with bioprostheses from March 2014 to December 2018 were retrospectively included. Patients with previous pacemaker or ICD implantation were excluded. Electrodes were implanted on the diaphragmatic surface of the right ventricle, with the generator placed in a subcostal epigastric position. The mean age was 57±16 years; 70% were women. Thirty-five cases (44%) were reoperations, of which 19 (24%) involved left-sided valvular disease, and 24% had associated moderate or severe right ventricular dysfunction. Isolated TVR was performed in 28 patients (35%), while it was combined with mitral valve replacement in 29 patients (36%), aortic valve replacement in 11 patients (14%), and other combinations in 12 patients (15%). Single-lead electrodes were used in 41 patients (51%), and two leads in the remainder. Postoperatively, 11 patients (14%) died, and 10 (12.5%) were lost to follow-up, leaving a total of 59 patients for analysis. The mean follow-up period was 36 months. Cardiac pacing was required in nearly half (46%) of patients, although the need for pacing decreased to 5% after the first year. An additional 9 patients died during follow-up. Severe device-related complications occurred in 2 patients (2.5%), including one case of cardiac arrest secondary to inappropriate pacing and another case involving an infection at the generator pocket site, requiring device removal. Other complications included lead dysfunction in 3 patients and an upgrade to resynchronization therapy in 4 patients. No cases of premature battery depletion were reported. 

The primary limitation of the study is that it is a single-center, retrospective study not exclusively focused on the tricuspid valve, so caution should be exercised when extrapolating the results. Nevertheless, the authors conclude that following TVR, the need for permanent cardiac pacing arose in nearly half of the patients due to postoperative atrioventricular conduction disorders. This high incidence, combined with an acceptable safety profile, could support a strategy of prophylactic epicardial pacing for patients undergoing TVR. 

COMMENTARY: 

Following TVR, one of the consequences of annular suturing may be dysfunction resulting from permanent damage or temporary inflammation/tension of the atrioventricular node, located at the apex of Koch’s triangle, adjacent to the septal leaflet. Techniques to minimize this phenomenon include anchoring the suture in this area to the leaflet itself with different reinforcements, such as pericardium or Teflon, or ventralizing this annular segment by placing the prosthesis at the atrial level outside this segment. Nonetheless, the subsequent need for pacemaker implantation remains high. Additionally, the presence of a prosthesis in the tricuspid position contraindicates the passage of an electrode through it due to dysfunction and high risk of future endocarditis. Consequently, the intraoperative implantation of a pacemaker lead, given the high incidence and traditional use of epicardial systems, aims to prevent a secondary procedure requiring general anesthesia by performing the implant at the same time. 

Although this study’s experience reports higher rates of cardiac pacing requirements compared to other series, it is important to note that many concomitant procedures are performed, with the associated increased risk of conduction system injury/dysfunction. However, as shown, permanent pacemaker implantation is not without complications, making prophylactic implantation an imperfect solution despite the authors suggesting an “acceptable” risk/benefit profile. In reality, adding an additional surgical procedure increases the likelihood of complications simply due to the inclusion of an extraordinary procedure. Therefore, the best approach should involve reserving each procedure as needed and considering alternative strategies. 

In this regard, several pacing options could be considered. Some include placing the pacemaker leads paravalvularly at the time of valve implantation, leadless pacemakers (also previously discussed in the blog), and electrodes in the coronary sinus. Each of these alternatives has its own risk-benefit balance. Paravalvular endocardial systems implanted during the surgical procedure are the least common, as they entail trapping the lead, preventing its removal in case of dysfunction, and potentially resulting in endocarditis. However, they do not interfere with the prosthesis and allow for dual-chamber pacing if the patient has sinus rhythm. Leadless pacemaker implantation is still under development, with limited experience. They could be placed in the ventricle, but their postoperative implantation would require transprosthetic manipulation with catheters, which is impossible in mechanical prostheses and complex with bioprostheses. Experience with dual-chamber systems of this type is even more limited. Coronary sinus electrodes, as the most suitable endocardial solution, enable dual-chamber systems but tend to have poor long-term stability and initially stimulate the left side. 

If the epicardial approach is chosen, implanting the leads without connecting them to the generator and placing them in an epigastric/subcostal position until the need for permanent pacing is confirmed appears to be a prudent solution. This second surgical step could be performed under local anesthesia if permanent pacing is indicated, with the only drawback being the implantation of epicardial leads that may not be used. A notable disadvantage of the epicardial approach includes higher pacing thresholds than endocardial systems and more frequent generator replacements. Additionally, we must consider current trends toward minimally invasive surgery, percutaneous approaches, and hybrid solutions, which could provide more appropriate responses to these issues by changing the paradigm of how future patients will be managed. 

Another noteworthy point is the high percentage of patients without long-term pacing needs, reinforcing the notion that early postoperative pacemaker implantation does not often yield optimal outcomes. In this study, early intervention was marked by prophylactic implantation from the beginning of the postoperative period. However, a substantial number of patients undergoing various procedures (arrhythmia ablations, valve surgeries, sutureless valve implants) experience spontaneous recovery within a period of up to two weeks postoperatively. 

As surgeons, we should perform TVR only when repair is not feasible, strive to minimize conduction tissue damage, and establish a collaborative strategy with cardiology teams to address atrioventricular block complications according to each unit’s practices. Nevertheless, it still seems prudent to reserve any intervention for when a clear indication is present, regardless of its perceived simplicity. 

REFERENCE: 

Bazire B, Para M, Raffoul R, Nataf P, Cachier A, Extramiana F, et al. Prophylactic epicardial pacemaker implantation in tricuspid valve replacement. Eur J Cardiothorac Surg. 2023. Dec 1;64(6):ezad344. doi: 10.1093/ejcts/ezad344