Despite its currently low incidence, post–acute myocardial infarction VSD remains one of the most devastating mechanical complications, associated with persistently high mortality rates that have shown minimal improvement over recent decades. Traditionally, the clinical debate has focused on the optimal timing of surgical repair, oscillating between emergent intervention and delayed surgery, as if the problem were primarily a matter of scheduling. However, over recent years there has been a progressive—largely evidence-scarce—shift toward delayed surgical strategies supported by mechanical circulatory support (MCS). This trend had already been reflected in real-world clinical practice described in previous European surveys, which we discussed and analyzed in this blog two years ago.

In parallel, in other advanced cardiogenic shock scenarios such as bridge to heart transplantation, microaxial assist devices have evolved from rescue tools into strategic therapies. They are now frequently deployed early to stabilize patients, preserve end-organ function, and buy decision-making time—particularly since the introduction of the Impella 5.5®, which enables not only bridge to decision but also prolonged stability until heart transplantation or durable ventricular assist device implantation. Within this context, the study by Murakami et al. explores whether the same philosophy can be effectively applied to the management of post-infarction VSD, analyzing not only the use of mechanical support but also the impact of device selection and initial support strategy.

The authors conducted a single-center retrospective study including 18 patients with post-infarction VSD treated with microaxial flow pump (mAFP) devices between 2017 and 2024. Patients were divided into two groups according to the type of device and initial access: a percutaneous group treated with Impella 2.5® or CP®, and a high-flow group supported with Impella 5.0® or 5.5® implanted surgically via the axillary artery. The primary aim was to compare clinical course, need for support escalation, access to surgery, and survival at discharge and at 100 days.

Survival to hospital discharge was significantly higher in the axillary access group (100% [5/5] vs 31% [4/13]; p = .029). Consistently, 100-day survival was also markedly superior in the axillary group, with a survival rate of 100% compared with approximately 30% in the percutaneous group, according to Kaplan–Meier analysis (p = .020). Seven patients in the percutaneous group (54%) required subsequent addition of venoarterial extracorporeal membrane oxygenation (VA-ECMO), and all of them died, whereas no patient in the axillary access group required ECMO escalation.

The authors conclude that early use of high-flow microaxial support implanted via the axillary artery may facilitate more effective hemodynamic stabilization in post-infarction VSD patients, enable delayed surgery under improved clinical conditions, and be associated with higher early survival, while explicitly acknowledging the limitations related to sample size and study design.

COMMENTARY:

This study delivers a clinically meaningful message that extends beyond a simple comparison of devices: in post-infarction VSD, the initial circulatory support strategy appears to be as relevant as surgical timing itself. The results suggest that initiating treatment with higher-capacity, more stable microaxial support is associated with improved survival and, crucially, with a real possibility of reaching surgical repair—or even heart transplantation in selected cases—without being overwhelmed by progressive multiorgan failure, and under clinically acceptable conditions.

It is no coincidence that this approach is now supported by the recent consensus document from the American Association for Thoracic Surgery, which positions early mechanical support—including microaxial devices—as a key tool to gain stability and time in post-infarction VSD. This effectively shifts the focus from “when to operate” to “how to reach surgery,” an aspect we analyzed in this blog only a few weeks ago when reviewing that consensus statement.

These findings align well with the paradigm shift that had already been suggested years ago by European clinical practice. Previous surveys on VSD management showed that most centers had adopted delayed surgery supported by mechanical assistance even before robust evidence became available. The work by Murakami et al. now offers a plausible pathophysiological and clinical explanation for this trend: it is not enough to simply “buy time”; it is essential to ensure adequate support from the outset so that time does not become a liability leading to progressive organ dysfunction.

The parallel with cardiogenic shock management as a bridge to transplantation is particularly illustrative. In that setting, recent experience has shown that early implantation of microaxial devices—especially high-flow systems via the axillary approach—can transform a scenario of hemodynamic collapse into a stable and predictable clinical course. In contrast, percutaneous Impella devices are more commonly used in combination with VA-ECMO for left ventricular unloading (the ECPELLA configuration), typically in patients with profound shock (INTERMACS 1 or SCAI E), which largely explains their poorer prognosis.

This nuance is essential for proper interpretation of the study results. It is therefore not surprising that patients initially treated with percutaneous Impella devices experienced worse outcomes, as they often represent a cohort with greater baseline severity and a more reactive support strategy. Similar to what has been reported in international and national bridge-to-transplant shock series, patients receiving Impella 5.5® as primary support usually correspond to less advanced shock stages, exhibit better hemodynamic response, and have a markedly superior prognosis compared with those who eventually require ECMO.

One of the most striking findings is the 100% mortality among percutaneous-group patients who required secondary ECMO. This observation reinforces a concept already recognized in other clinical settings: late escalation of support often reflects prior failure of stabilization and is associated with poor outcomes, representing the logical consequence of a reactive strategy. In contrast, the axillary access group required no escalation, demonstrated better perfusion parameters before surgery, and achieved significantly higher early survival.

Nonetheless, several important limitations warrant cautious interpretation. This is a small, single-center, retrospective series with a clear selection bias, as patients in the percutaneous group were globally more unstable at presentation. In addition, temporal factors related to institutional learning curves and the progressive introduction of higher-flow devices may have influenced outcomes. Even so, the core message remains compelling: a decisive initial strategy appears clinically more sound than a reactive, stepwise approach.

Overall, while this study alone does not redefine clinical guidelines, it clearly reinforces an emerging trend in everyday practice. As has occurred in advanced cardiogenic shock and heart transplantation, post-infarction VSD management seems to be entering a new era in which early, appropriate, and planned circulatory support becomes the cornerstone of therapy—potentially even more critical than the traditional debate surrounding surgical timing.

REFERENCE:

Murakami K, Hasegawa S, Miki A, Yamauchi H, Tanaka A, Ohashi T, et al. Impact of initial axillary microaxial flow pump on post-myocardial infarction ventricular septal defect management. Interdiscip Cardiovasc Thorac Surg.2025;40(11):ivaf253. doi:10.1093/icvts/ivaf253.