Early Insertion of Axillary Impella® With VA ECMO
Early Insertion of Axillary Impella® With VA ECMO
Veno-arterial extra-corporeal membrane oxygenation (VA-ECMO) is used as a rescue strategy for
 patients in acute hemodynamic deterioration such as cardiogenic shock and cardiopulmonary
 arrest with severe pulmonary congestion. VA ECMO is the fastest way to stabilize a patient
 with cardiogenic shock and improve end-organ perfusion. However, one of the major
 disadvantages of peripheral VA-ECMO is that it provides no left ventricular unloading and
 increases left ventricular (LV) afterload secondary to the retrograde blood flow. Therefore,
 LV wall tension and myocardial oxygen demand may actually increase in the setting of VA ECMO.

 The Impella® device is a miniature rotary blood pump which can be inserted retrograde across
 the aortic valve. In this configuration, it withdraws blood from the LV and ejects it into
 the ascending aorta. It unloads the left ventricle, reducing LV wall tension and myocardial
 oxygen demand and increasing myocardial blood flow. The Impella® 5.0 is an FDA approved pump
 designed for intermediate support in patients with severe, cardiogenic shock. The axillary
 positioning allows for early extubation and ambulation and is more stable than groin
 placement.

 In present practice, the decision to place an Impella® pump in VA-ECMO patients is based on
 the perceived need for direct LV unloading or when a bridge device is required to transition
 off ECMO support. Patients with peripheral VA ECMO are managed with inotropic agents at the
 beginning and once patients develop pulmonary edema mechanical LV unloading is considered
 electively. The advantage of LV unloading with Impella® has been demonstrated in recent
 studies. We also reported that concomitant implantation of Impella® with VA ECMO for LV
 unloading resulted in improved survival and recovery of ventricular performance in patients
 with cardiogenic shock. Compared to delayed elective LV unloading, early LV unloading could
 lead to decreased pulmonary edema, improved oxygenation delivery to the myocardium, increased
 chance of LV recovery and improved survival.

 The objective of this prospective study is to assess whether the early direct ventricular
 unloading using axillary Impella® leads to higher rates of cardiac recovery, defined as
 survival free from mechanical circulatory support, heart transplantation or inotropic support
 at thirty days, compared with the conventional, elective placement of Impella® after
 developing significant pulmonary congestion.
This prospective, single-arm trial will include all consecutive patients undergoing
 cannulation of peripheral VA ECMO at the Massachusetts General Hospital (MGH) from April 2019
 to March 2020. All enrolled patients will undergo surgical placement of Impella® via axillary
 artery within 48 hours after peripheral VA ECMO initiation and be managed with early
 extubation and ambulation strategy.

 After Impella® placement, there will be no research procedures performed. Subjects will
 receive standard of care and the subject's progress will be documented throughout the 30 days
 study follow-up. The data obtained from the electronic medical record in Epic health record
 system at MGH will be reviewed throughout the study.

 The primary outcome of this study will be survival at 30 days. Prespecified secondary end
 points will include the rate of death from cardiovascular causes, New York Heart Association
 (NYHA) functional class, LV function (assessed by echocardiography), and the rate of stroke,
 neurological functional status, acute kidney injury, vascular complications, and bleeding.

 The enrolled subjects (early Impella®) would be compared with patients who underwent current
 elective placement of Impella® after cannulation of VA ECMO (elective Impella®) in the past
 two years. Student's t-test (for continuous variables) or Fisher exact test (for categorical
 variables) will be used for between-group comparisons. The primary endpoint in the data
 analysis is binary: 30-day survival. The null hypothesis of no difference between early
 Impella® and elective Impella® will be tested using logistic regression. The secondary
 endpoint, the rate of death from cardiovascular causes, NYHA functional class, LV function,
 and the rate of stroke, neurological functional status, acute kidney injury, vascular
 complications, and bleeding, will be addressed using competing risks hazard regression
 models. This is a pilot study for the future multicenter study. If this study demonstrates no
 inferiority or any significant superiority, we will proceed to do multicenter prospective
 study. Power analysis will be assessed based on the result of this preliminary study.
Inclusion Criteria:

 -  Age ≥18

 -  Impaired LV systolic function with ≤35% of left ventricular ejection fraction (LVEF)

 -  Enlarged LV with ≥50mm of left ventricular diastolic diameter (LVEDD) on
 echocardiogram

 Exclusion Criteria:

 -  Non-cardiac etiology

 -  Surgically correctable cardiac abnormality

 -  Recent significant pulmonary embolism

 -  Severe pulmonary hypertension

 -  Acute aortic dissection

 -  Presence of mechanical aortic valve prosthesis

 -  Presence of left ventricle thrombus

 -  Pre-existing Impella® 5.0

 -  Critical aortic stenosis

 -  Uncorrectable system malperfusion under ECMO support

 -  Significant cerebrovascular accident