Left ventricular assist device


When waiting for a heart transplant LVAD can support patients and is known as a bridge to transplant.

LVAD can be used as a bridge to recovery in patients with reversible heart failure-it is surgically implanted to pull blood from the left ventricle and pumping it into the aorta.

LVADs enhance quality in duration of life in patients with advanced heart failure, irrespective of eligibility for cardiac transplant.

More than 15,000 LVADs implanted in the US, with more than 2000 LVADsy implanted annually.

The LVAD can be connected to an external battery pack and a control system by a conduit that passes and through the abdomen.

The LVAD Systems consists of an inflow cannula placed in the apex of the heart, the pump itself, and an outflow conduit connected to the aorta.

Continuous flow LVAds have a fixed pump speed that does not change with exercise, selected to unload the left ventricle without causing excessive emptying and right ventricular overload.

A fully magnetic frictionless levitating pump with blood flow pathways and a pulse in the pump due to fixed rotor speed changes improves long-term survival by decreasing pump thrombosis and disabling strokes, but only moderately improves bleeding complications.

Patients with irreversible heart failure may have a LVAD placed for the remainder of their lives, if they are not heart transplant candidates, and in this case this is known as destination therapy.

In a randomized trial in patients with severe heart failure who underwent LVAD as a destination therapy survived longer than patients who were managed medically (Rose EA et al).

Right ventricular dysfunction is considered the most common cause of recurrent heart failure after left ventricular assist device implantation.

Patients with Recurrent heart failure symptoms after LVAD implantation display more profound hemodynamic derangements, greater burden of  right ventricular failure, and increase rates of all-cause mortality compared with LVAD recipients will resolve heart failure symptoms.

The two-year survival rate among patients with severe heart failure treated with continuous flow LVADs compared to patients treated with older pulsatile-flow LVADs was significantly better 58% versus 24% (Slaughter MS et al).

A Mayo Clinic study revealed that two year survival rate of patients with destination therapy with a LVAD was 74% (Boilson BA et al).

Continuous flow LVADs have a fixed pump speed that does not change with exercise, selected to unload ventricle without causing all excessive emptying and right ventricular overload.

Continuous flow LVADs have a fixed pump speed that does not change with exercise, selected to unload the left ventricle without causing excessive emptying and right ventricular overload.

LVAD recipients usually have improved resting and exercise hemodynamics, with lower

mean pulmonary arterial pressure and pulmonary capillary wedge pressure and higher cardiac index.

Complications with ventricular assist devices include stroke, infection, and multi-organ failure.

Left ventricular assist device related infection can occur at the driveline site, at the device pocket site, or on the internal surface of the pump near the end accordion.

Driveline site infections are the most common type of LDAD related infections, occurring in 1.3 to 1.4 per 100 patient months.

Patient with LVAD related infections have a 5.6 times greater mortality at one year and higher rates of other complications such as bleeding and stroke.

Mucosal surface bleeding, particularly in the G.I. tract is the leading cause of hospitalization and healthcare resource use and is increasing in frequency since the introduction of continuous flow LVAD’s.

These bleeding complication, which often occur, are attributed to high shear stress and low pulse pressure due to continuous flow promoting the development of acquired von Willebrand’s disease, an AV malformations.

Driveline infections are typically treated with antibiotics, however in cases of persistent infection, pump exchange may be necessary.

Complications include right ventricular dysfunction, aorticregurgitation, arrhythmias, or pump thrombosis that may lead to recurrent symptoms of heart failure.

New or recurrent heart failure symptoms can occur in LVAD recipients as a result of right ventricular dysfunction, left-sided dysfunction or both.

Due to improved durability in survival, the eligible population has expanded to include less critical patients with longer support times.

May help reverse myocardial remodeling seen in congestive heart failure, but recovery sufficient to explant the device occurs only in 5-24% of patients and there is a relatively high incidence of early recurrence.

Utilized as a bridge to heart transplantation and usually employs a pulsatile volume displacement device that fills with and ejects blood in a cyclic fashion similar to systole and diastole in the normal heart.

Progressive heart induced cachexia, renal and hepatic dysfunction due to poor perfusion, pulmonary venous hypertension, systemic hypotension, and intractable angina not responsive to therapy or revascularization may suggest the need for L VAD support.

Refractory ventricular tachycardia/fibrillation may be treated with LVAD implantation during failed catheter ablations or when multiple implantable cardioverter-defibrillator shocks may worsen ventricular function.

Patients with end-stage heart failure caused by restrictive and hypertrophic cardiomyopathy may benefit from LVAD.

Requires extensive surgical dissection, a recipient that has a large body habitus, the need for a large diameter percutaneous lead, a loud pump operation, and limited long term mechanical durability with requirement of device changes.

Newer models have continuous flow with rotary pump technology and a smaller size than preexisting devices.

Newer models with a simpler design have longer durability and can be used in some women and adolescents because of smaller size.

Hemodynamic parameters improve with lower pulmonary arterial and pulmonary capillary wedge pressure and higher cardiac output.

Approximately 15% of the LVAD recipients require in hospital renal replacement therapy, which is associated with prolonged length of stay hospitalizations, increased risk of all cause mortality, and G.I. bleeding.

Quieter operation of continuous flow machines.

HEARTMART II is a small, axial-flow left ventricular assist device with initial thrombosis occurrence rate of 2-4%, however recent studies suggest increasing rates greater than 8% and they are associated with elevated LDH levels (Starling RC et al).

Most patients with complex congenital heart disease are not candidates for mechanical assisted circulation support.

Unrecognized patent foramen ovale or atrial septal defect can contribute to hypoxemia from right to left shunting after LVAD implantation and paradoxical emboli.

Postoperative complications include hospital readmissions for G.I. bleeding, device infection, thromboembolic events, and right ventricular failure.

The MOMENTUM3  randomized trial found the receipt of a fully magnetized levitated centrical flow LVAD versus an axial flow LVAD was associated with a better composite outcome in higher likelihood the overall survival at five years (Mehta M).

In patients treated with a fully magnetically levitated LVAD, the avoidance of aspirin as part of an anti-thrombotic regimen, which includes vitamin K antagonist, is not inferior to a regimen containing aspirin, does not increase thromboembolism risk, and is associated with a reduction in bleeding events. ( ARES-HM3 Investigators).



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