To the TandemHeart team at&#160;LifeSparc.

This procedure and protocol have been approved by the institutional review board and the United States Food and Drug Administration (FDA).
1. Patient criteria
<ol>
	<li>Include patients with CS stage B and above as defined by the SCAI consensus statement1.</li>
	<li>Include as bridge to transplant or durable left ventricular assist system in stage D heart failure.</li>
	<li>Include as bridge to recovery in AMI complicated by CS.</li>
	<li>Exclude contra-indication to ...

Hemodynamics of LAFAB&#160;device: 
The hemodynamic profile of the LAFAB device is distinct from other pVADs. By draining blood directly from the LA&#160;and returning it to the femoral artery, the device bypasses the LV completely. In doing so, it reduces LV end diastolic volume and pressure, contributing to improved LV geometry, and thereby effecting a decrease in LV stroke work. However, by returning the blood back into the iliac artery/descending aorta, afterload increases. This...

Cardiogenic shock (CS) is a state of tissue hypoperfusion with or without concomitant hypotension, in which the heart is unable to deliver sufficient blood and oxygen to meet the body&#39;s demands, resulting in organ failure. It is classified into stages A to E by the Society of Cardiovascular Angiography and Interventions (SCAI): stage A - patients at risk for CS; stage B - patients at beginning stage of CS with hypotension or tachycardia without hypoperfusion; stage C - classic CS with cold and wet phenotype requiring inotropes/vasopressors or mechanical support to maintain perfusion; stage D - deteriorating on current medical or mechanical support requiring escalation to more advanced devices; and stage E - includes patients with circulatory collapse and refractory arrhythmias who are actively experiencing cardiac arrest with ongoing cardiopulmonary resuscitation1. The most common causes of CS are acute MI (AMI) representing 81% of cases in a recently reported analysis2, and acute decompensated heart failure (ADHF). CS is classically characterized by congestion and impaired perfusion, manifested by elevated filling pressures (pulmonary capillary wedge pressure [PCWP], left ventricular end-diastolic pressure [LVEDP], central venous pressure [CVP], and right ventricular end-diastolic pressure [RVEDP]), decreased cardiac output (CO), cardiac index (CI), cardiac power output (CPO), and end-organ malfunction3. In the past, the only available treatments for AMI complicated by CS were early revascularization and medical management with inotropes and/or vasopressors4. More recently, with the advent of mechanical circulatory support (MCS) devices and the recognition that escalation of vasopressors is associated with increased mortality, there has been a paradigm shift in the treatment of both AMI and ADHF related CS5,6.
In the current era of percutaneous ventricular assist devices (pVAD), there are a number of MCS device platforms/configurations available, which provide univentricular or biventricular circulatory and ventricular support with and without oxygenation capability7. Despite steady increases in the use of pVADs to treat both AMI and ADHF CS, mortality rates have remained largely unchanged5. With emerging evidence for possible clinical benefits to early unloading of the left ventricle (LV) in AMI8 and early use of MCS in AMI CS9, the use of MCS continues to increase.
The Left Atrial to Femoral Artery Bypass (LAFAB) MCS device bypasses the LV by draining blood from the left atrium (LA) and returning it to the systemic arterial circulation via the femoral artery (Figure 1). It is supported by an external centrifugal pump that offers 2.5-5.0 liters per minute (L/m) flow (new generation pump, designated as LifeSPARC, capable of up to 8 L/m flow) depending on the size of the cannulas. Once the blood is extracted from the LA via the transseptal venous cannula, it passes through the external centrifugal pump which recirculates the blood back into the patient&#39;s body via the arterial cannula placed in the femoral artery.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/62140/62140fig01.jpg" /> 
Figure 1: LAFAB setup. Image courtesy of TandemLife, a wholly owned subsidiary of LivaNova US Inc. <a href="https://www.jove.com/files/ftp_upload/62140/62140fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr >
			<td >For LAFAB (TandemHeart)</td>
			<td ></td>
			<td ></td>
			<td></td>
		</tr>
		<tr >
			<td >Factory Supplied Equipment for circuit connections.</td>
			<td >TandemLife</td>
			<td ></td>
			<td></td>
		</tr>
		<tr >
			<td >ProtekSolo 15 Fr or 17 Fr Arterial Cannula&#160;</td>
			<td >TandemLife</td>
			<td ></td>
			<td></td>
		</tr>
		<tr >
			<td >ProtekSolo 62 cm or 72 cm Transseptal Cannula&#160;</td>
			<td >TandemLife</td>
			<td ></td>
			<td></td>
		</tr>
		<tr >
			<td >TandemHeart Controller&#160;</td>
			<td >TandemLife</td>
			<td ></td>
			<td>For adjusting flows/RPM</td>
		</tr>
		<tr >
			<td >TandemHeart Pump&#160;</td>
			<td >LifeSPARC</td>
			<td ></td>
			<td>Centrifugal pump</td>
		</tr>
		<tr >
			<td >For RAPAB (ProtekDuo)</td>
			<td ></td>
			<td ></td>
			<td></td>
		</tr>
		<tr >
			<td >Factory Supplied Equipment to complete the circuit.&#160;</td>
			<td >TandemLife</td>
			<td ></td>
			<td></td>
		</tr>
		<tr >
			<td >ProtekDuo&#160; 29 Fr or 31 Fr Dual Lumen Cannula&#160;</td>
			<td >TandemLife</td>
			<td ></td>
			<td></td>
		</tr>
		<tr >
			<td >TandemHeart Controller&#160;</td>
			<td >TandemLife</td>
			<td ></td>
			<td>For adjusting flows/RPM</td>
		</tr>
		<tr >
			<td >TandemHeart Pump&#160;</td>
			<td >LifeSPARC</td>
			<td ></td>
			<td>Centrifugal pump</td>
		</tr>
	</tbody>
</table>

use of a percutaneous ventricular assist device/left atrium to femoral artery bypass system for cardiogenic shock

The left atrial to femoral artery bypass (LAFAB) system is a mechanical circulatory support (MCS) device used in cardiogenic shock (CS) that bypasses the left ventricle by draining blood from the left atrium (LA) and returning it to the systemic arterial circulation via the femoral artery. It can provide flows ranging from 2.5-5 L/min depending on the size of the cannula. Here, we discuss the mechanism of action of LAFAB, available clinical data, indications for its use in cardiogenic shock, steps of implantation, post-procedural care, and complications associated with the use of this device and their management.
We also provide a brief video of the procedural component of device therapy, including the pre-placement preparation, percutaneous placement of the device via transseptal puncture under echocardiographic guidance and the post-operative management of device parameters.

Clinical applications of LAFAB device 
The technique and feasibility of a percutaneous trans-atrial left ventricular bypass system were first described in the 1960s by Dennis et al.11,12. However transseptal puncture was not initially widely adopted due to complications with the septostomy technique. Over the last decade, with advancements in the field of percutaneous interventions, operators have accumulated experience with atrial septostom...

Watch this Scientific Journal Video about Use of a Percutaneous Ventricular Assist Device/Left Atrium to Femoral Artery Bypass System for Cardiogenic Shock at JoVE.com

Use of a Percutaneous Ventricular Assist Device/Left Atrium to Femoral Artery Bypass System for Cardiogenic Shock

The following article describes the stepwise procedure for placement of a device (e.g., Tandemheart) in cardiogenic shock (CS) that is a percutaneous left ventricular assist device (pLVAD) and a left atrial to femoral artery bypass (LAFAB) system that bypasses and supports the left ventricle (LV) in CS.

The left atrial to femoral artery bypass (LAFAB) system is a mechanical circulatory support (MCS) device used in cardiogenic shock (CS) that bypasses the ...

The tandem heart is a percutaneously implanted mechanical circulatory support device that is used for the treatment of cardiogenic shock, particularly in situations like LV thrombus or severe aortic stenosis. And it provides a support of about five liters per minute. Demonstrating today's procedure will be myself and Dr.Swethika Sudaravel, chief cardiology fellow from UNMC.To set up the controller, begin by opening the box of the device and access the battery door to place the batteries two at a time in the controller with the logo facing away from the controller screen. The batteries should be well seated with the groove on the battery aligning with the key battery housing. After placing the four batteries, attach the controller to the dock, ensuring it is fully seated on the dock.Then connect the power cord to the power outlet of the controller and plug in the other end of the cord to the wall socket for AC power. Once done use the clamp to mount the dock and controller on an intravenous pole and operate the buttons on the side to turn on the controller. Open the package, and the sterile drape.Then lay out the components of the priming tray on the sterile table, next, plug the pump drive line into the controller, remove the protective caps on the tubing before inserting the end of the blue tubing into the blue port and the red tubing into the basin. Place the basin in the fill ready, tilted back position, away from the blue port. When the basin is filled with four liters of saline, put the lid and place the basin in the fill ready, tilted back position away from the blue port.Gently tap the tubing and the pump to remove any small air bubbles present and ensure that all the air has been removed before turning on the pump from the non sterile end in the same way, remove tiny air bubbles in the oxygenator by gently tapping the oxygenator, followed by positioning the outflow tubing at a higher level in the 12 o'clock position for the air bubbles to rise above and escape out. Once all the air bubbles are removed clamp the inflow and outflow tubing and stop the pump, remove the inflow and outflow tubing from the basin and then attach the green oxygen supply tubing to the gas port on the oxygenator to complete the circuit. After preparing the patient in a sterile manner, pass the transesophageal, echocardiogram or TEE probe into the esophagus to obtain the basic images, if using an intracardiac echocardiogram, or ICE, obtain the images after venous access.Using a TEE probe or ICE, identify the ideal spot for septostomy of the interatrial septum and confirm the absence of any thrombus in the left atrium where the inflow cannula will be positioned, use the Bicaval view on TEE at the region of the phase ovales, to expose the interatrial septum. Using the modified Seldinger technique obtain femoral venous access via ultrasound guidance and insert tape 0.032 inch guidewire into the vein and position the tip in the superior vena cava. Advance the baylis sheath over the guidewire into the superior vena cava, remove the guidewire and under fluoroscopic or TEE ICE guidance, withdraw the baylis sheath towards the interatrial septum.Using fluoroscopy or TEE ICE, identify the optimal site for transeptal puncture and advance the baylis needle into the interatrial septum, administer anticoagulant to the patient to achieve activated clotting time more than 250 seconds before performing transeptal puncture, then perform transeptal puncture by advancing the baylis needle and sheath into the left atrium. After confirming the sheath is in the left atrium by fluoroscopy, remove the needle and insert a guidewire into the left atrium then remove the baylis sheath. With a two stage dilator, dilate the venous access and the interatrial septum to insert the transeptal cannula.After advancing the cannula into the left atrium remove the introducer and guidewire and wait for back bleed before clamping. Finally secure the cannula to the patient. Next, obtain femoral arterial access via the modified Seldinger technique using ultrasound and fluoroscopic guidance at the level of the femoral head and insert a 0.035 inch guidewire.Serially dilate the arterial access site appropriate to the size of the selected arterial cannula, insert the arterial cannula and remove the introducer and guidewire. Wait for back bleed then clamp. Ensuring constant infusion of saline, over the two ends of the cannulas connect the transeptal or venous cannula to the pump inlet marked in blue and the arterial cannula to the pump outlet marked in red, remove the venous clamps first and start the pump from the controller box then release the other clamps sequentially while constantly checking for air in the circuits.Release the arterial clamp last. To optimize the flow, adjust the pump speed. After confirming the position of the cannula under fluoroscopy and TEE or ICE, secure the circuit to the patient.To prevent pump thrombosis and stroke, it's crucial to maintain the therapeutic anticoagulation for as long as the pump is in place. The application of left atrium to femoral artery bypass or LAFB may be associated with few complications, such as cardiac perforation, and tamponade, acute limb ischemia and hemolysis. Proper precautionary measures and management procedures are important, avoid complications related to LAFB.In a trial comparing LAFB and ventricular assist device or VAD, a significant improvement in cardiac power index with the VAD device was observed. The LAFB device was effective in lowering pulmonary capillary wedge pressure and improving cardiac index, VAD displayed significant progress in PCWP and CI.The most important steps of the procedure are performing the transeptal puncture under meticulous imaging guidance, getting arterial access using ultrasound and fluoroscopy and making the vein to vein connections of the circuit.

Use of a Percutaneous Ventricular Assist Device/Left Atrium to Femoral Artery Bypass System for Cardiogenic Shock

Abstract