Rotary mechanical circulatory support systems

Abstract

A detailed survey of the current trends and recent advances in rotary mechanical circulatory support systems is presented in this paper. Rather than clinical reports, the focus is on technological aspects of these rehabilitating devices as a reference for engineers and biomedical researchers. Existing trends in flow regimes, flow control, and bearing mechanisms are summarized. System specifications and applications of the most prominent continuous-flow ventricular assistive devices are provided. Based on the flow regime, pumps are categorized as axial flow, centrifugal flow, and mixed flow. Unique characteristics of each system are unveiled through an examination of the structure, bearing mechanism, impeller design, flow rate, and biocompatibility. A discussion on the current limitations is provided to invite more studies and further improvements.

Keywords: Assistive technology; biomedical devices; heart failure; life support systems; mechanical circulatory support; orthotics; rehabilitation devices; ventricular assistive device.

Figure 1.

Different flow regimes in rotary ventricular assistive devices (reprinted with permission^,). (a) Centrifugal flow, (b) axial flow and (c) mixed flow.

Figure 2.

Typical P–Q results for centrifugal, axial, and mixed CF-VADs at the same speed.^,–

Figure 3.

Bearing mechanisms in rotary ventricular assistive devices (reprinted with permission^,). (a) Mechanical pivot, (b) hydrodynamic radial (left) and thrust (right), (c) permanent magnet (combined with hydrodynamic bearing) and (d) electromagnetic.

Figure 4.

HeartAssist 5 pump (Courtesy of ReliantHeart, Inc.). (a) Adult and (b) low body-surface-area (pediatric).

Figure 5.

HeartAssist 5 ventricular assist system (Courtesy of ReliantHeart, Inc.).

Figure 6.

HeartMate II pump with sealed grafts (Courtesy of Thoratec Corp.).

Figure 7.

X-Ray of a patient with HeartMate II LVAS (Courtesy of Thoratec Corp.).

Figure 8.

INCOR pump (Courtesy of Berlin Heart GmbH).

Figure 9.

Insertion of inlet cannula of INCOR into the left ventricular apex (Courtesy of Berlin Heart GmbH).

Figure 10.

Impella LVAD (Courtesy of Abiomed, Inc.). (a) Impella 2.5 and (b) Illustration of the implanted device (pediatric).

Figure 11.

Approximate size of the HeartWare HVAD (Courtesy of HeartWare International, Inc.).

Figure 12.

Illustration of the HeartWare HVAD system (Courtesy of HeartWare International, Inc.).

Figure 13.

HeartMate III (Courtesy of Thoratec Corp.).

Figure 14.

Thoratec PediMag and CentriMag BiVADs (Courtesy of Thoratec Corp.). (a) PediMag and (b) CentriMag.

Figure 15.

Thoratec CentriMag installed on the electromagnetic motor (Courtesy of Thoratec Corp.).

Figure 16.

Implantation of Thoratec CentriMag versus HeartMate II (Courtesy of Thoratec Corp.)

Figure 17.

BPX-80 LVAD (Courtesy of Medtronic). (a) BPX-80 Bio-Pump Plus and (b) cross section.

Figure 18.

Bio-Pump BP-80 and Bio-Console560 (Courtesy of Medtronic).

Figure 19.

BP-50 LVAD (Courtesy of Medtronic). (a) BP-50 Bio-Pump and (b) Bio-Console 540.

Figure 20.

Approximate size of Synergy Micro-Pump (Courtesy of CircuLite, Inc.)

Figure 21.

Modified versions of CircuLite MicroPump (Courtesy of CircuLite, Inc.). (a) endovascular system, (b) right heart support, (c) all-support and (d) child support.