Improved survival after concomitant surgical ablation and a clip—a strong argument for performing it more often

In surgical ablation (SA) of atrial fibrillation (AF) concomitantly with other cardiac operations, observational studies have demonstrated a high rate of return of sinus rhythm up to 1–2 years postoperatively. However, it is more difficult to evaluate benefits of SA in a longer perspective, in everyday cardiac surgical practice, outside of prospective follow-up protocols. This is where register studies come in. While registers seldom can determine long-term rhythm outcome or quality-of-life of patients postoperatively, it is possible to analyse such variables as stroke incidence or long-term survival, related to SA and after adjustment for confounders, in a large number of patients.

In this issue of EJCTS, Pasierski et al. analysed data from the Polish KROK-registry of almost 34000 cardiac surgical patients with preoperative AF, who underwent surgical treatment of AF or not, concomitantly with coronary or valve procedures [1]. The cohort was stratified for SA + left atrial appendage occlusion (LAAO), SA only, LAAO only or no surgical AF treatment. The main finding was a significant survival benefit both short term and up to 6 years after surgery in patients who had concomitant surgical AF treatment, after proper risk adjustment. There was also a gradient in treatment effect so that the highest survival benefit was seen in patients undergoing the combination of SA and LAAO.

The results of this study clearly point in the same direction as other reports in recent years [2, 3]. In fact, a previous multicentre propensity-matched study by many of the same authors, showed that SA concomitant with other cardiac operations was associated with improved long-term survival [4]. The finding that SA + LAAO has the uppermost positive effect has also been shown previously [3] and is certainly a confirmation of what cardiac surgeons are hoping for when performing these procedures. It is a logical thought that there should be a complementary effect on survival by simultaneously addressing the arrhythmia and the localized risk for thromboembolic events associated with AF in the same procedure. From recent randomized data, we do know the importance of LAAO in cardiac surgery [5].

The study by Pasierski et al. demonstrates another well-known but unfortunate outcome. SA as a concomitant procedure is clearly underutilized in routine cardiac surgery, despite class I-2a recommendations in clinical practice guidelines. Although numbers are probably slowly on the rise in recent years, in this study covering surgery from 2012 to 2022, only 15% of the operated patients had SA, whereas 81% had no surgical AF treatment at all. Other studies have shown similarly low rates, with SA being most often performed in mitral valve procedures (25%) and most seldom in CABG (12%) [6].

In many register studies of outcomes after SA, it is hard to distinguish what kind of lesion-set or ablation technology was used. However, with several centres and surgeons involved in these studies, the umbrella term SA often represents a quite heterogenous set of techniques, thereby implying an expected variation in postoperative rhythm outcome. The gold standard surgical treatment of AF is the biatrial Cox-maze IV procedure, including LAAO, and it is obviously being performed even less frequently than the rates stated for concomitant SA. Actually, in the present study, the ablation technique was accounted for. Only 1332 out of 33 949 patients (3.9%) with preoperative AF underwent a Cox-maze IV. There are likely multiple reasons for surgeons choosing not to add SA to a cardiac operation. The combined procedure may be deemed as too risky, given co-morbidities or poor left ventricular function, although studies actually show a lower perioperative mortality when adding SA. Moreover, the atria may be assessed as too dilated to achieve success with SA, although there are recent data showing the opposite [7].

From a purely technical standpoint, it is quite understandable that in a closed atrial operation such as AVR or CABG, it is a change of game plan to cannulate separately, open the atria and perform SA, preferably a Cox-maze IV. However, in mitral surgery, it is increasingly difficult to understand why 70–75% of patients with AF do not get concomitant SA in routine practice. This is probably the primary area for improvement for cardiac surgeons performing SA. Given proper training, it is not an overly difficult procedure to perform a Cox-maze IV in the open atria in mitral sternotomy cases. It is also a safe and reasonably quick procedure, especially clipping the LAA. In minimally invasive mitral cases, however, concomitant SA and LAAO could be perceived as a higher hurdle to pass. Nevertheless, it should be a prioritized part of the operation, particularly in younger patients with documented AF, paroxysmal or persistent. After all, we try to perform mitral valve repair as often as possible with the objective of improving the patient’s prognosis. The study by Pasierski et al. shows that we should strive to ablate AF and occlude the LAA for precisely the same reason.

REFERENCES