Cardiogenic shock on presentation and preoperative deterioration of hemodynamics are strong predictors of mortality.1, 2 Although AHA guidelines recommend early surgical repair regardless of hemodynamic status, the timing of surgery and use of VADs in the setting of post-MI VSD with cardiogenic shock remains controversial and should be individualized.3 The main challenge in treating patients with post-MI VSD is whether to correct the defect immediately or to delay surgical closure and allow time for tissue and organ recovery.2 For our patients in cardiogenic shock, we opted for early surgical repair of VSD with intraoperative Impella placement to allow immediate LV decompression with continuous drains of LV, thus maintaining flow from LV to the aorta, preventing worsening of cardiac performance and organ malperfusion, while resolving the pulmonary to systemic shunt.4 We believe that this technique protects the integrity of the VSD patch, providing additional time for septal tissue maturation, and it gives surgeons the opportunity to perform concomitant interventions (i.e, CABG, valve repair/replacement etc.).
In the recent years, the peripheral arterial approach in implanting catheter-based VADs has become the predominant technique5. Due to the urgency in cardiogenic shock in our patients, we placed the device through a graft sewn to the distal ascending aorta during CPB; a strategy more time sensitive than an axillary or femoral approach. Moreover, trans-axillary Impella placement in such cases is beneficial for LV venting and continued support allowing for early bed mobilization of the patients compared to femoral access.
Extracorporeal membrane oxygenation (ECMO) is commonly used in such patients; however, ECMO has been shown to compromise LV contractile function with increased LV end-diastolic pressure, LV afterload, impaired myocardial blood flow and often requires additional intervention such as LV venting. In cases of advanced cardiogenic shock with severe RV dysfunction and multi-organ failure, we have previously utilized ECMO with Impella support. The Impella 5.5 SmartAssist is less invasive and provides more practical and effective postoperative treatment and mechanical support in LV dysfunction with myocardial stunning than ECMO.
With a forward flow to the general circulation of up to 6.2 L/min and optical sensor technology, the Impella 5.5 SmartAssist is best able to fully decompress the heart of all currently available mechanical circulatory support devices. This is particularly important in patients with large body habitus or in cardiogenic shock with a vasodilatory component, which may be the result of suboptimal LV decompression. Other advantages of the Impella 5.5 include device removal and repositioning at bedside with SmartAssist technology; furthermore, we observed an improvement in RV function with resolution of pulmonary edema and mitral insufficiency. These advantages might lower the decision threshold for the initiation of mechanical circulatory support to restore the hemodynamics, preventing the aggravation of organ failure and potentially leading to improved outcomes in patients with post-infarction VSD in cardiogenic shock.