Ventricular restoration surgery has been one of the most overlooked techniques in the past decade. This was largely due to the limited studies addressing the challenges posed by the STICH study, a key reference for this procedure. The primary objective of ventricular restoration is to recover a functional left ventricle after ischemic damage, by excluding areas with transmural akinetic and/or dyskinetic necrosis (ventricular aneurysm). However, this procedure often includes myocardial revascularization, correction of functional mitral regurgitation, and ablation of ventricular arrhythmias. Thus, the technique aims to restore the heart as closely as possible to its pre-ischemic state, as discussed in previous entries of this blog.

The STICH study was the first large-scale effort to test a technique previously suggested by observational studies and a small trial by Ribeiro et al. at the beginning of the century. Other techniques, such as Batista’s ventricular reduction, latissimus dorsi cardiomyoplasty, or even “pacopexia” in honor of the late Francisco Torrent Guasp, are now considered historical. The technique followed in the STICH study, and later popularized for ventricular restoration surgery, was primarily described by Vincent Dor. In summary, this technique involved a ventriculotomy through akinetic/dyskinetic areas to the left of the left anterior descending artery, with identification of viable adjacent myocardium using complementary echocardiographic and MRI studies. Following this identification, a circular suture was applied with or without a pericardial patch, avoiding interference with the subvalvular mitral apparatus. The ventriculotomy was then closed longitudinally to achieve adequate seal, although overlap techniques were also described to prevent potential distortion of ventricular architecture (overlap technique). The goal was to reduce the size of the dilated ventricular cavity, mechanically excluding non-viable akinetic or dyskinetic myocardial areas and thereby partially correcting the tenting forces restricting mitral valve systolic motion. This exclusion, combined with scar resection, also serves as a ventricular arrhythmia correction measure, although ablation lines can be created from the infarcted area to an electrically neutral region, such as the mitral annulus. The remaining viable myocardium would be restored by complete revascularization, with mitral valve repair or replacement performed via ventriculotomy or conventional transatrial approach.

The STICH study was designed as a multicenter, randomized study, initially enrolling 2136 patients with a left ventricular ejection fraction <35%. Patients were randomized to undergo revascularization surgery and ventricular restoration versus isolated revascularization. Recruitment encountered challenges, including slow enrollment due to the rarity of the procedure, ultimately resulting in a highly heterogeneous population. Moreover, the fundamental limitation and primary cause for the study’s results was that the ventricular volume reduction, the technique’s main objective, averaged only 19%, compared to the stipulated protocol criterion of over 30%. This limited reduction led to a lack of significant differences between the ventricular restoration surgery group and the isolated revascularization group in terms of mortality or rehospitalization rates at 5 years. Additionally, with the inclusion of a cohort receiving only optimal medical treatment, the study extended follow-up (STICHES study) and provided valuable insights into the role of myocardial viability in decision-making for ischemic dilated cardiomyopathy revascularization, as also previously discussed. By the time reanalyses were conducted focusing on subgroups of the cohort with proper surgical restoration, which showed clinical benefits, ventricular restoration had already started losing popularity.

The San Donato group was involved in the initial STICH cohort and has continued the technique to the present day. In the current work, they present the largest series with the longest follow-up of ventricular restoration surgery to date, including patients operated on between 2001 and 2019. Their surgical technique was particularly systematic, performing aneurysmectomy and using a reference balloon to adjust the residual ventricular cavity to the appropriate size (50 cc/m2). This method ensured significant ventricular size reductions, a crucial factor for differential benefits over simple revascularization. They ultimately included 725 patients and compared them with the STICH cohort of 501 patients who underwent ventricular restoration surgery. The San Donato cohort patients were older (66 vs. 61.9 years; p < 0.01), required more mitral valve surgery, had lower diabetes rates, and a lower mean indexed end-systolic volume (77 vs. 80.8 cc/m2; p = 0.02). The mortality rate for the San Donato cohort was 7.4%. The propensity-matched analysis of the two populations determined that:

1. At a mean follow-up of 9.9 years, matching the STICHES study follow-up, the survival rate for the San Donato cohort was superior to that of the optimal medical therapy arm (HR = 0.45; p < 0.001).
2. At the same mean follow-up, the San Donato cohort also showed lower mortality than the isolated myocardial revascularization arm of the STICHES study (HR = 0.63; p < 0.001).
3. At a mean follow-up of 4 years, as published for the STICH study, the San Donato cohort had lower mortality than the STICH study cohort (HR = 0.71; p = 0.001).
4. Furthermore, they demonstrated a greater reduction in left ventricular size compared to the STICH restoration group (LVESVI reduction: -39.6% vs. -10.7%; p < 0.001). In a similar subanalysis, as conducted in previous post-hoc analyses of the STICH study, they found that greater reductions in left ventricular size were associated with lower mortality in both cohorts.

The authors conclude that post-infarction patients with left ventricular remodeling who underwent ventricular restoration surgery in a high-experience center showed better long-term outcomes than those reported by the STICH/STICHES trial. This suggests that the technique should be revisited through new clinical trials to test its clinical utility hypothesis.

COMMENTARY:

The San Donato group’s impressive results in ventricular restoration surgery are beyond question. They hold the most published experience on this topic and have demonstrated that their series may hold superior value over the STICH study. They can certainly be considered a reference center and should lead initiatives, as proposed in their conclusions, to create new evidence to overcome the limitations associated with ventricular restoration surgery.

The study addresses the inherent limitations of an observational analysis, as the San Donato cohort is retrospective, and the STICH cohort was not collected explicitly for this work. As with all studies addressing heart failure with reduced ejection fraction, having wide temporal series can introduce bias due to significant pharmacological advancements in recent times. Nonetheless, both cohorts are contemporaneous for the most part, so it can be expected that the medical treatment protocols were updated simultaneously.

To add one more fact, the San Donato series also shows excellent survival, reaching 74.7% at 5 years and 54.9% at 10 years, higher than the typical 5-year 50% survival for patients with severe ventricular dysfunction. The main predictors of this long-term mortality were identified as age, diabetes, and uncorrected mitral regurgitation. These positive outcomes are likely related to careful patient selection (lower LVESVI) and improved surgical technique (higher target reductions in left ventricular cavity size, with a cut-off at 60 cc/m2, and mitral valve correction).

Once again, a clinical trial dogma is questioned. The San Donato group demonstrates that when done well, surgery often yields positive results. It is increasingly important to evaluate the methodology of these so-called class A evidence sources and continue generating high-quality evidence before findings, such as those for ventricular restoration surgery, irreversibly impact clinical guidelines.

REFERENCE:

Gaudino M, Castelvecchio S, Rahouma M, Robinson NB, Audisio K, Soletti GJ, et al. Long-term results of surgical ventricular reconstruction and comparison with the Surgical Treatment for Ischemic Heart Failure trial. J Thorac Cardiovasc Surg. 2024 Feb;167(2):713-722.e7. doi: 10.1016/j.jtcvs.2022.04.016.