Mechanical assist devices Flashcards
How does IABP improve myocardial oxygen supply to demand ratio
- reducing the tension-time index (systolic wall tension) by reducing the impedance to left ventricular ejection
- increasing the diastolic pressure-time index by increasing coronary blood flow during during diastole
List complications of IABP
Vessel perforation Arterial branch occlusion Acute aortic insufficiency Gas escape/catheter rupture peripheral thrombo-embolism acute aortic dissection wound problems chronic claudication femoral neuralgia femoral pseudo-aneurysm
How are LVAD classified
Pulsatile: Thoratec, Heart mate I,
Non-pulsatile (continuous) flow: Heart mate II, Jarvik,
Location:
Totally implantable
paracorporeal
percutaneous
List indications for advanced mechanical support
Post-cardiotomy cardiogenic shock post-MI cardiogenic shock High-risk PCI Hypothermia rewarming Bridge to transplantation Bridge to recovery Long-term destination therapy Backup for high risk cardiac surgery
What are the main uses of a LVAD
Bridge to Transplantation
Bridge to recovery
Bridge to destination therapy
Bridge to decision
List potential complications of LVAD
Operative mortality 10-20%
Major bleeding (20 to 60% require mediastinal reexploration
Right heart failure (20 to 40%)
Device Malfunction
Major infection (within 3 months about 28%)
Neurologic dysfunction 8 to 20%
List available ventricular assist devices
Heartmate I (thoratec) NovaCor Thoratec DeBakey VAD Heartmate II Jarvik Van Lionheart Abiocor TAH Cardiowest
What are considerations when placing a LVAD
potential reversibility of cardiac dysfunction
cause of the caridac dysfunction
degree of right and left ventricular dysfunction
amount of circulatory support needed
patient size
Importance of the device for myocardial functional recovery
Whether the patient is candidate for cardiac transplantation
Anatomic location of collapse or deterioration
Expected duration of support
The patient’s age and severity of comorbid conditions
What are theoretical advantage of VADs
Maintains end-organ perfusion and prevents end-organ damage. End-organ damage is a predictor of survival
Resting the stunned myocardium by unloading the ventricle
Promote “reverse remodeling” by improving myocardial contractility
What are indications to do BiVAD over just LVAD
Fitzpatrick from UPEN suggested do RVAD if
CI < 2.2
RV stroke work index < 0.25 mmHg/L/M2
severe preoperative RV dysfunction on eco
Pre-operative creatinine
previous cardiac surgery
systolic BP< 90
List 4 contra-indications for mechanical circulatory support as a bridge to tranplantation
Systemic life-threatening (serious) illness
irreversible renal dysfunction
irreversible hepatic dysfunction
patient is not a candidate for transplantation
The RECOVER I: multicenter prospective study of Impella 5.)LD for post cardiotomy circulatory support
JTCS Feb 2013
Howard Frazer
16 pts post being weaned off CPB enrolled in a prospective single-arm feasibility study.
The primary endpoint was survival of the patient to.
outcomes:
recovery of native heart function was obtained in 93% of patients with bridge to other therapy in 7%
Survival at 30 days, 3 months and 1 year was 94%, 81%, and 75%
List some factors for RVAD usage after LVAD
female gender small body surface area noishcemic etiology Low mean and diastolic pulmonary pressyres Low RVSWI Pre-operative circulatory support
Describe the Impella
Impella 5.0 (Abiomed) is a 21 French microaxial pump based 9 French catheter. It is capable of producing up to 5 L/min of flow.
The left peripheral (LP) is designed to be inserted peripherally.
The left direct (LD) is tended to be placed directly into the ascending aorta via a 10-mm vascular graft.
Details of Impella
The device straddles the aortic valve with inflow residing in the left ventricular cavity and the outflow at the level of the STJ.
Managed at beside and intended for 1 week duration.
Potential benefits of the impella
Improvement in cardiac output direct ventricular unloading (reduction in left ventricular end diatolic pressure and volume) reduced myocardial oxygen demand improved oxygen demand improved coronary perfusion infarct size limitation
ABIOMED5000
Pneumatically controlled temporary external pulsatile assist device.
SIngle-use blood pumps activated by a pneumatic drive console. Blood pump composed of dual chamber system that incorporates atrial (filling) chamber with a ventricular (pumping) chamber.
resistant again ventricular arrhythmias.
inserted sternontomy.
What is Levitronix CentriMag device
Ventricular assist system designed for treatment of patients with acute cardiogenic shock of any etiology
Can generate as much as 10L/min flow is capable of support for 30 days.
Unique in that it is driven with a bearingless motor that enables the spinning component within the pump to be magnetically leviatated and rotated without contact or wear.