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mechanical circulatory support

The concept of assisted circulation began with the development  of cardiopulmonarybypass (CPB). As the techniques for extracorporeal circulationutilizing CPB were perfected during the 1950s, the era of open heart surgery began. When CPB was introduced into the clinical arena in 1953 open intracardiac repairs were performed for the first time. Ultimately, attempts were made to
utilize CPB for temporary support or replacement of cardiac function. However,
the oxygenator, an integral component in the CPB circuit has a large blood contacting
surface area which results in a significant blood:biomaterial interaction.
Activation of the systemic inflammatory response and the resultant capillary leak
syndrome produce profound systemic side effects. Furthermore, attempts to utilize
CPB for long-term cardiac support were limited by bleeding associated with
the need for full systemic anticoagulation and damage to formed blood elements.
As open heart surgery became more commonplace patients with postoperative
ventricular dysfunction were encountered creating a need for a device capable
of supporting the patient’s circulation.1 The simplest such device, the intraaortic
balloon pump (IABP) is a catheter mounted balloon that is positioned in the descending
thoracic aorta. When properly timed with the patient’s native cardiac
rhythm the IABP is capable of improving coronary perfusion, reducing left ventricular
afterload and augmenting cardiac output to a very modest degree. The
IABP was first employed clinically in 1968. Milestones in IABP development include
the conversion from an open to percutaneous insertion technique in 1980,
manufacture of balloons of smaller dimension that can be employed in patients
with a small body habitus and in the pediatric patient population and timing
schema that permit balloon pump use in patients with rapid and/or irregular cardiac
rhythms. The IABP is now a standard form of therapy for patients with a variety of cardiovascular diseases.
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