Long Term Mechanical Circulatory Support Flashcards
Would you put a mechanical or bioprosthetic aortic/mitral valve into a patient undergoing LVAD and why?
Bioprosthetic because if there is stasis with LVAD, there is a high risk for thrombosis of the mechanical valve
Who performed the first LVAD and when?
Who performed the first successful LVAD?
Who performed the first successful bridge to transplant LVAD?
DeBakey in 1963, patient survived for 4 days
DeBakey in 1966, patient survived for 10 days and was weaned off
Texas Heart in 1978 using the Model 7 abdominal LVAD
What was the first pump to be managed in an outpatient setting?
Heartmate XVE
What was the first trial to demonstrate the success of LVADs?
Heartmate XVE in the REMATCH trial which showed a 50% absolute reduction in mortality at 1 and 2 years.
What are the pros and cons of continuous flow LVADs versus pulsatile flow LVADs?
Continuous flow LVADs are mechanically simpler, more resistant to wear and tear and smaller than pulsatile flow LVADs. In the Heartmate II DT trial, were shown to need reduced replacement, reduced sepsis, respiratory failure, renal failure, arrhythmias and rehospitalization.
However, CF LVADs can cause increased GI bleeding and degeneration of smooth muscle and elastic fibers in aortic tissue as well as stasis and thrombus formation in the carotid bulb and aortic valve cusps.
Overall, CF technology remains the future of MCS.
What are the types of VADs available currently?
Centrimag - surgical - centrifugal - temporary - flows up to 10L/min
Impella - percutaneous - left sided support - flows up to 5L/min - right sided version available
TandemHeart - percutaneous - left atrial -> left femoral via transseptal approach - flows up to 4/min
Heartmate II - surgical - FDA approved for BTT (2008) and DT (2010)
Jarvik 2000 - surgical - trial pending - FDA investigational device exemption
INCOR - surgical - not FDA approved, CE mark approved
EVAHEART - surgical - CE mark, trial pending
HVAD - surgical - CE mark, FDA approved for BTT (2012), DT trial pending
HeartAssist 5 - surgical - CE mark, FDA IDE, BTT trial pending
Heartmate III - surgical - CE mark pending, FDA IDE approved, BTT/DT trial pending
MVAD - surgical - CE mark pending, FDA IDE pending
SynCardia TAH - surgical - pulsatile pneumatic, CE mark approved, FDA humanitarian device exemption 2004
What are the ACCF/AHA HF Stages?
Stage A - At risk but no structural heart disease
Stage B - Structural heart disease but no signs or symptoms of HF
Stage C - Structural heart disease but with past or current signs or symptoms of HF
Stage D - Refractory HF requiring specialized interventions
What is the NYHA Classification?
I - no limitation in physical activity
II - mild limitation in physical activity - ordinary physical activity results in symptoms
III - marked limitation of physical activity - 1 flight of stairs
IV - symptoms at rest or unable to carry out any physical activity without symptoms of HF
What is the INTERMACS Classification and what are the stages?
A classification of NYHA III-IV patients to stratify these patients in more detail. Developed in 2008.
1 - crash and burn - intervention needed within hours
2 - sliding on inotropes - intervention needed within days
3 - stable on inotropes but repeated failure to wean - dependent stability - intervention needed elective over a few weeks
4 - frequent flyer - elective over weeks to months as long as treatment of episodes restores stable baseline, including nutrition
5 - housebound - intervention needed variably, depending on nutrition, organ function and activity
6 - walking wounded - intervention needed variably, depending on nutrition, organ function and activity
7 - patient living comfortably with meaningful activity limited to mild exertion - transplant or MCS not currently indicated
Which scores are used to predict peri-operative mortality?
3 risk scores:
MELD score
MELD-XI score for patients on warfarin
Heartmate II multivariable risk score (HMRS)
Relative contraindications to MCS?
Irreversible major end-organ dysfunction, severe hemodynamic instability, profound coagulopathy, complex congenital anomalies, restrictive heart disease with decreased ventricular dimensions, active infection (wait 5 days after culture documented clearance from infection before surgery), chronic pre-operative dialysis
What concurrent operations are indicated in LVAD implantation?
bioprosthetic AVR - moderate or greater AI
bioprosthetic TVR or repair with ring - moderate or greater TR
PFO or ASD closure
Why can LVAD implantation cause RV failure?
- Sudden increase in cardiac output and venous return (increased preload)
- LVAD reduces pulmonary hypertension (afterload) but it can take time which does not help the RV
- Interdependence between the RV and LV can result in RV distortion and dysfunction due to LV unloading.
What are the average flows of Heartmate II, III and HVAD?
10000, 5000 and 2500 respectively.
What are the parameters of Centrimag?
Pump speed 3000-4000 Pump flows 4-5L RAP/LAP 10-15mmHg CVP 8-12mmHg Target ACT 160-180s
