Ventricular-assist Devices (CentriMag) as Temporary Support for Severe Heart Failure
June 29, 2010 | Emerging Technology Reports
Proprietary Names: CentriMag Back-Up Console; CentriMag Blood Pump; CentriMag Blood Pumping System (also referred to as CentriMag Extracorporeal Blood Pumping System); CentriMag Primary Console; CentriMag Right Ventricular Assist System (RVAS also referred to as Right Ventricular Assist Device or RVAD); CentriMag VAS Generic Device Names: bearingless centrifugal pump; biventricular assist device; centrifugal blood pump; circulatory support system; continuous-flow rotary pump; extracorporeal blood pumping system; magnetically-suspended ventricular assist device; mechanical circulatory support device; short-term ventricular assist device; single ventricle assist device
CentriMag extracorporeal magnetically levitated ventricular-assist devices, including the Extracorporeal Blood Pumping System, the RVAS, and VAS, provide short- (up to 6 hours in the United States) or longer-term (up to 30 days in Europe) support for patients with acute heart failure and cardiogenic shock that most often arises from acute myocardial infarction (AMI). Cardiogenic shock can also occur from post-cardiotomy trauma, in which ventricular failure occurs after left ventricular-assist device (LVAD) implantation or failed cardiac transplantation.1-7 Patients in these scenarios require ventricular support due to decreased cardiac blood flow and often have multi-system organ failure that is refractory to optimal medical therapy with intra-aortic balloon pumps and inotropic support.6 These patients require short- or longer-term support with mechanical devices or extracorporeal membrane oxygenation (ECMO). ECMO typically provides support of only a few hours. Implanting a longer-term mechanical device often results in poor postoperative outcomes due to organ failure, unclear neurologic status, and hemodynamic instability.6 For that reason, clinicians may choose devices that offer short-term circulatory support until they can further evaluate the patient to determine whether native heart function will return, whether they should use a long-term device, or whether they should conduct a heart transplant.3,7,8 This clinical scenario is described as a bridge-to-decision (BTD) and is the focus of this report.1,3,5,6,8 Currently, some U.S. clinicians have expressed interest in extending beyond six hours the period of time the device is used for support because a decision may not be able to be made within the 6-hour timeframe for which the device is labeled in the United States.
The manufacturer claims that CentriMag VADs offer certain hemodynamic advantages over other circulatory support devices by employing a magnetically levitated impeller to improve blood handling and decrease trauma to the heart.9 Other purported advantages include elimination of frictional wear, which reduces the heat generated because the impeller is suspended; increased blood flow around the impeller to reduce stasis and lower complication rates (e.g., hemolysis, bleeding, infection, stroke); and improved pump response for increased safety.6,10
The system can be configured to provide left-, right-, or bi-ventricular support. All CentriMag systems include the following components: 9-12
Optional components include the following:10
To implant the device, the surgeon completes a median or lateral sternotomy. The surgeon may place the patient on cardiopulmonary bypass to maintain hemodynamic stability.2,4 Surgeons may use anticoagulation before or after the procedure.2,7To support the left ventricle, the surgeon inserts the inflow cannula into the left atrium and places the outflow cannula into the ascending aorta.4 To support the right ventricle, the surgeon inserts the inflow cannula into the right atrium and places the outflow cannula into the main pulmonary artery.4 Surgeons place the cannulae subcutaneously so that they exit the skin in the lower quadrants. The surgeon secures the cannulae exit sites with sutures. Next, the clinician removes any air from the cannulae while the operating room staff primes the pump and tubing with saline.1,4 Lastly, the surgeon attaches the inflow and outflow cannulae to the primary console and gradually increases the pump speed to reach the required flow.1 After closing...