Keywords
LVAD, left ventricular assist device, RVAD, right ventricular assist device, Centrimag, impella, ventricular assist, heart failure
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Since the first implantation of a left ventricular assist device (LVAD) by Dr. Michael DeBakey in 1966, the search for durable short- and long-term mechanical support has resulted in a myriad of devices and expanded indications. Targeted funding by the National Institutes of Health (NIH) and industry has resulted in several innovative technologies with which the surgeon must be familiar in order to recommend appropriate mechanical support therapy, when indicated.
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As waiting times for transplantation lengthened, clinical experience was gained with various devices. Today, pulsatile and nonpulsatile mechanical circulatory support devices are increasingly being used as bridges to transplantation and as destination therapy. The ReMATCH trial has shown that LVADs have a permanent place as destination therapy in end-stage heart failure. In this chapter, we describe techniques used for the implantation of various common devices for temporary and durable ventricular support in heart failure.
Step 1
Surgical Anatomy
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The anatomy of pump insertion is similar for most devices discussed in this chapter. The inlet cannula of both externally and internally placed LVADs is usually implanted in the left ventricular apex. The diaphragmatic surface of the left ventricle between the ventricular septum and the origin of the papillary muscles for the inlet cannula or pump can also be used ( Fig. 32.1 ). This convenient flat space is particularly suited for implantation of small centrifugal force pumps and intraabdominally placed axial flow pumps.
Figure 32.1
Diaphragmatic surface anatomy of the left ventricle.
Step 2
Preoperative Considerations
1
Indications for Use of Various Ventricular Assist Devices
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Temporary ventricular assist devices are typically used in the setting of acute left or right ventricular dysfunction or for univentricular support for interventional procedures. Devices are available that can be placed percutaneously via open vascular exposure or via mediastinal access. Temporary ventricular assist devices can be deployed rapidly in various clinical locations (e.g., intensive care unit [ICU], operating room [OR], or catheterization laboratory). A variety of devices are commercially available, including the Impella (Abiomed, Danvers, MA) series of left and right ventricular assist devices that provides temporary axial flow support in a low-profile device. The Impella 2.5 and Impella CP ( Fig. 32.2 ) can be inserted percutaneously, or the higher flow Impella 5.0 ( Fig. 32.3 ) can be inserted via right axillary or femoral cut-down for higher flows. The newly released Impella RP ( Fig. 32.4 ) is intended for right heart support via percutaneous venous access. Numerous extracorporeal centrifugal pumps (e.g., CentriMag [Thoratec, Pleasanton, CA] or Tandem heart) are available for left and/or right ventricular support ( Fig. 32.5 ). We currently prefer to use the CentriMag in our institution because of its relative ease of use and the ability to splice in cardiotomy reservoirs for transfusion, oxygenators, and renal replacement devices. There is an ever-increasing number of patients who present with acute, acute on chronic, or chronic heart failure that require temporary or durable mechanical circulatory support. This chapter provides an overview of the major temporary and durable ventricular assist devices that are currently available. Descriptions of the indications and implantation techniques are outlined.
Figure 32.2
Impella CP ® device.
© 2017 Abiomed, Inc. All rights reserved.
Figure 32.3
Impella 5.0 ® device.
© 2017 Abiomed, Inc. All rights reserved.
Figure 32.4
Impella RP ® device.
© 2017 Abiomed, Inc. All rights reserved.
Figure 32.5
CentriMag ® blood pump.
Reproduced with permission of St. Jude Medical, © 2017. All rights reserved.
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For long-term implantable support, the HeartMate II (Thoratec) and HeartWare HVAD (HeartWare, Framingham, MA) are the two current continuous-flow devices that are most commonly used. The HeartMate II ( Fig. 32.6 ) is an axial flow pump requiring implantation in the abdomen, whereas the HeartWare HVAD ( Fig. 32.7 ) is a centrifugal pump that is implanted within the pericardium itself. Other implantable LVADs are also available either commercially or on a trial basis.
Figure 32.6
Heartmate II ® left ventricular assist device.
Reproduced with permission of St. Jude Medical, © 2017. All rights reserved.
Figure 32.7
Heartware™ HVAD™ left ventricular assist device.
Reproduced with permission of Medtronic, Inc.
Step 3
Operative Steps
1
External Temporary Devices
Impella
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The Impella 2.5 and Impella CP devices are regularly inserted using a percutaneous access technique either in the cardiac catheterization laboratory or the OR. Femoral arterial access is obtained using the Seldinger technique, the artery is dilated up, and a tear-away sheath is placed. The Impella device is then inserted after priming, guided into the left ventricle, and positioned across the aortic valve under fluoroscopic and/or echocardiographic guidance. After adequate positioning is obtained, the automated controller is activated, and an appropriate power level is selected for the desired cardiac output.
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Insertion of the Impella 5.0 is performed via either a femoral cut-down technique with direct arterial cannulation or, more commonly at our institution, an axillary artery cut-down technique ( Fig. 32.8 ). We prefer to place an 8- to 10-mm tube graft on the axillary artery with 4-0 polypropylene sutures and cannulate the graft with the Impella 5.0 device. The device is then advanced and positioned as previously described using intraoperative fluoroscopy and echocardiography. We prefer to close the cut-down site with layers of interrupted sutures to help prevent bleeding and infection while the device is in place.
