Ventricular Assist Devices

Dr.Elamaran.ESenior Resident

Dept. of CTVS

Mechanical circulatory support (MCS) is a means of imparting energy for forward flow of blood in the body by manmade devices.

History

0 In the presence of prolonged cardiac unloading with an LVAD, myocyte size and myocardial collagen content and collagen production (fibrosis) generally decline.

0On an anatomic and functional level, chronic LVAD support generally results in reduction in left ventricular mass as well as left ventricular end-systolic and end-diastolic volume - improvement in left ventricular ejection fraction

Indications Duration of use

0Bridge to recoveryPostcardiotomy cardiogenic shock. Post acute-myocardial infarction (MI) cardiogenic shock. Myocarditis-induced cardiogenic shockSupport during medical or ablative therapy for

intractable dysrhythmias.0Bridge to Transplant0Bridge to Destination Therapy

Indications1. NYHA functional class IV symptoms2. Life expectancy < 2 years3. Not a candidate for heart transplantation4. Failure to respond to optimal medical management for at

least 60 of the last 90 days5. Left ventricular ejection fraction 25%6. Refractory cardiogenic shock or cardiac failure7. Continued need for intravenous inotropic therapy limited by

symptomatic hypotension, decreasing renal function, or worsening pulmonary congestion

8. Body surface area > 1.5 m2

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Contraindications 0 Age > 65 years, unless minimal or no other clinical risk factors

0 Chronic kidney disease with serum creatinine level 3.0 mg/dL

0 Severe chronic malnutrition (BMI < 21 kg/m2 in males and

< 19 kg/m2 in females)

0 Morbid obesity (BMI 40 kg/m2)

0 Mechanical ventilation

0 Recent or evolving stroke

0 Neurological deficits impairing the ability to manage device

0 Coexisting terminal condition (eg, metastatic cancer, cirrhosis)

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0 Abdominal aortic aneurysm > 5 cm

0 Biventricular failure in patients older than 65 years

0 Active systemic infection or major chronic risk for infection

0 Fixed pulmonary or portal hypertension

0 Severe pulmonary dysfunction (eg, FEV1 < 1 L)

0 Impending renal or hepatic failure

0 Multisystem organ failure

0 Heparin-induced thrombocytopenia

0 Significant underlying psychiatric illness or lack of social support

that may impair ability to maintain and operate VAD

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Design of Ventricular Assist Device

Basic Components of VAD

1. Blood pump2. Controller3. Power source4.Inflow cannula5.Outflow cannula

Krishnamani, R. et al. (2010) Emerging ventricular assist devices for long-term cardiac support

Nat. Rev. Cardiol. doi:10.1038/nrcardio.2009.222

Pulsatile VAD

Continuous flow VAD

Technique of Insertion0Pulmonary artery catheter0 Intraoperative TEE

assessment of biventricular functionevaluation of aortic insufficiency presence of a patent foramen ovale identification of intracardiac and aortic air bubbles

during implantation and subsequent de-airing maneuvers

assessment of inflow cannula position within the left ventricle.

0Device pocket creation

0CPB established

0Heart is maintained in a continuously beating state without cardioplegic arrest

0Left ventricular apex is displaced, and an opening is created in the left ventricle for insertion of the apical cannula

0Deairing of the device

0End-to-side anastomosis is then constructed to the right lateral aspect of the ascending aorta

0Drive line is brought out through a long subcutaneous tunnel and passed off the surgical field and connected to the pump console

0Full pumping is established, and CPB is discontinued with continued surveillance by TEE for air and right ventricular function