ECPELLA 2.0—Minimally invasive biventricular groin‐free full mechanical circulatory support with Impella 5.0/5.5 pump and ProtekDuo cannula as a bridge‐to‐bridge concept: A first‐in‐man method description

Cardiogenic shock (CS) from biventricular heart failure that requires acute mechanical circulatory support (MCS) is associated with high mortality. Different MCS methods and techniques have emerged as a standard of care in CS. Nevertheless, the routine MCS approach carries multiple limitations such as limb ischemia, missing of left ventricular unloading and immobilization.

K E Y W O R D S biventricular mechanical support, cardinogenic shock (CS), groin-free, heart failure (HF), Impella ECLS prevent full mobilization, as the cannulas are either directly connected to the aorta or are placed into the groin vessels. These cannulation techniques not only prevent patient mobilization but also lead to limb ischemia. 5 Further complications are systemic inflammation, infections, and multiorgan failure that have to be taken into consideration. Infection (eg, groin cannulation site infections, sepsis, pneumonia) is one of the most common complications in ECLS occurring in up to 13% of adult patients. 6 Thrombotic or air embolism and bleeding may cause cerebrovascular accidents. Inadequate decompression of the failing LV causes a backlog of blood into the lung with subsequent pulmonary congestion and a failure of the right ventricle. Especially in the setting of a dilated, poorly contracting heart with severe systolic dysfunction, decompression by LV venting might be crucial for the recovery of myocardium. 7 To address LV unloading, the concept of Impella (2.5 or CP) system in combination with ECLS has already been described as ECPELLA. However, other ECLS limitations and complications persist. 8 We present a novel approach to establish a full-flow MCS for patients in CS due to acute biventricular heart failure. ECPELLA 2.0 is a first-in-man concept of a groin-free MCS consisting of a full-flow axial flow pump (Impella 5.0/5.5) as left ventricular assist device (LVAD) in combination with the TandemHeart/ProtekDuo system as right ventricular assist device (RVAD) that allows full biventricular support with an option of an upgrade using an oxygenator that would facilitate rapid weaning from the respirator, mobilization, and physical exercise of the patient on full support. In both, our patients there was no need of using a membrane oxygenator. The ProtekDuo cannula, in combination with any centrifugal pump, offers the advantage of minimally invasive percutaneous full right heart support. 9 The ProtekDuo cannula is a flexible, dual lumen and partially wire-reinforced cannula providing drainage of venous blood through the outer 29 Fr. lumen from the right atrium and output through the tip of the inner 16 Fr. cannula into the pulmonary artery, with optional lung support by adding an oxygenator into the circuit. The cannula can be combined with any centrifugal pump as a temporary RVAD.

| METHODS
Our one-stage implantation protocol includes initial Impella implantation followed by percutaneous implantation of the Protek-Duo cannula via the right internal jugular vein (IJV) under fluoroscopy and TEE guidance as previously described. 7 The ProtekDuo cannula crosses the tricuspid valve, right ventricle (RV) and pulmonary valve into the main pulmonary artery.
Heparin was applicated immediately before implantation (target  implantation 2 weeks later with explantation of the Impella 5.0 and leaving the temporary RVAD in situ. In the intraoperative TEE, the prior aortic regurgitation appeared to be mild-to-severe. We performed an aortic valve replacement as a concomitant procedure. On the first postoperative day (POD), the patient was weaned from the respirator and full mobilization continued. The temporary RVAD was weaned according to our protocols 10 Figure 1B) and the bilirubin levels decreased ( Figure 1D) as a sign of a kidney-and liver recovery. Patients were extubated on POD 2. The patients were weaned off the MCS after hemodynamic and clinical parameters (mean arterial pressure >65 mm Hg, central venous oxygen saturation >65%, urinary output >0.5 mL·kg· −1 ·h −1 , echocardiographic findings). Impella was removed surgically bedside. Both patients left the intensive care unit (ICU) to complete mobilization and full recovery process to receive outpatient care. As both patients were eligible for a heart transplant, the listing process was initiated.
The groin-free ECPELLA 2.0 concept allows for full mobilization on temporary BIVAD with no risk of limb ischemia or groin vessel injury. Moreover, this strategy enables advanced physical therapy, facilitating recovery in ICU. Support duration on the ECPELLA 2.0 was 9 and 14 days, respectively, before successful LVAD implantation was performed. Both patients are well and have been discharged from our department.

| DISCUSSION
CS refractory to medical therapy due to biventricular heart failure carries a high mortality and remains a medical challenge. 2 These patients may require MCS as a bridge-to-recovery or bridge-totransplant. In both our cases the patients were referred to us in advanced CS with the failing end-organs (INTERMACS I). As previously shown, the outcome of the LVAD implantation in highrisk patients suffering from CS improves after the temporary use of peripheral MCS as compared to immediate durable LVAD implantation. 12 Hence, ECLS is considered a standard of care for these patients. Although the use of MCS carries a high rate of complications, the utilization increases rapidly. 2 Nevertheless, central and peripheral ECLS carries certain limitations that need to be addressed.
These include bleeding, limb ischemia, prolonged intubation, immobilization, restricted time on ECLS-support due to bleeding and thromboembolic complications and cerebrovascular accidents. 3 As a consequence, our group developed an alternative concept of an interventional/minimally invasive ECPELLA 2.0. It provides LV unloading, full biventricular support, is completely groin-free allowing for immediate full mobilization of the patient. The very limited procedure trauma results in early extubation and prevention of ventilator-associated complications. 13 While left-sided short-term MCS is unable to relief systemic venous congestion, RV-dysfunction or failure is common in patients receiving LVAD. 9 Our strategy carries the advantage of leaving the RVAD in place during and after LVAD implantation to prevent RV-failure after durable LVAD implantation to explant the temporary RVAD during ICU course at the bedside. 10 Although none of the patients had lung failure, this concept preserves the opportunity to add an oxygenator in the RVAD circuit.
We kept our goal ACT between 180 and 220 seconds combining the recommended anticoagulation manufacturer protocols and had no bleeding or thrombotic complications. 9 A major advantage of this concept is the combination of already available systems. Implantation may also be able to be performed in a cath lab by the heart team. 14 In the absence of cardiac surgeon access to the axillary artery can be provided by a general or vascular surgeon.

| CONCLUSION
In summary, we report the first-in-man groin-free biventricular support "ECPELLA 2.0" for patients suffering from biventricular failure and CS (INTERMACS I), allowing for a full biventricular support with reliable LV unloading, the option for adding an oxygenator in the RVAD circuit an immediate early mobilization. ECPELLA 2.0 is an excellent concept that provides full-flow support and preconditioning for a potential durable ventricular assist device (VAD) without the need for a thoracotomy in the first line. In addition, ECPELLA 2.0 can also be used as a bridge-to-decision in acute situations, where the treatment concept cannot be determined immediately due to the complexity of a pathology. In conclusion, the ECPELLA 2.0 concept is an innovative treatment for acute CS with relevant advantages as compared to conventional ECLS therapy and up-to-date percutaneous concepts. As these patients often have a complicated postoperative course in ICU, it is imperative to provide swift physical therapy and exercise opportunities for muscle gain that will support recovery. 15 Further studies may follow to collect more data for this concept.