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
Definition of severe HF - EF <25% and Stage D HF
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
What is a PAPI? (Pulmonary artery pulsatility index)
Systolic pulmonary artery pressure - diastolic pulmonary artery pressure / right atrial pressure. A PAPI under 1.85 is used to predict RV dysfunction post LVAD
What is the RV stroke work index used for and what is the formula?
It is used to determine need for potential RVAD during LVAD implant
RVSWI >6 - no need for RVAD
RVSWI 4-6 - consider NO and RVAD
RVSWI <4 - consider RVAD
Formula:
(Mean PAP - CVP) x SVI x 0.0136 = RVSWI
What are indications for MCS for Destination therapy?
Class 1: INTERMACS 1-3
Class 2a: INTERMACS 4
Other features suggestive:
Frequent HF hospitalization
Intolerant to neuro-hormonal antagonists
NYHA III – IV functional limitation despite OMT
End-organ dysfunction due to low CO
Increasing diuretic requirement
CRT non-responder
Inotrope dependent
Peak VO2 low (<14mL/kg/min) or <12 on beta blockers
PVR <8WU
Not candidates for transplant
Contraindications for device support?
Absolute –
Active infection
Severe PAD
Active bleeding
Contraindication to anticoagulation
Severe irreversible end-organ dysfunction
Severe RV failure
Relative –
Cancer with life expectancy <2 yrs
BMI >35
Neurological or psychosocial disease that makes care for LVAD problematic
PVR >8WU, Age >80
Life-limiting illness: severe liver disease (MELD >17)
Lung disease (Predicted FEV1 or DLCO <50%), Renal disease (eGFR <30)
Hematological: recent HIT, refuse blood transfusion
Psychosocial: inability to care for LVAD device, lack of social support, significant psychiatric illness, substance abuse, Hx of non-compliance
What are the indications for concomitant valves at the time of LVAD insertion?
Recommended Concomitant Procedures (When Indicated)
Procedure Indication
Aortic Valve Repair or Replacement For significant aortic regurgitation (moderate-severe), since it can reduce LVAD effectiveness.
Mitral Valve Repair If severe mitral regurgitation persists despite unloading by the LVAD. Usually, LVAD alone is sufficient.
Patent Foramen Ovale (PFO) Closure Recommended in patients with right-to-left shunting to prevent hypoxia.
Atrial Septal Defect (ASD) Closure If significant shunting exists, closure is advised.
Tricuspid Valve Repair (or Replacement) Considered if moderate-to-severe tricuspid regurgitation is present to improve right heart function.
Aortic Valve Closure (Surgical Oversizing or Sewing Shut) In continuous-flow LVADs, the aortic valve can be surgically closed if regurgitation is significant and repair/replacement is not feasible.
CABG (Coronary Artery Bypass Grafting) If significant coronary artery disease (CAD) is present, CABG can be performed simultaneously to optimize myocardial perfusion.
Procedures to Avoid or Perform with Caution
Procedure Concerns
Elective Aortic Valve Replacement (AVR) for Stenosis Usually not necessary as LVAD reduces afterload. However, consider if severe symptomatic aortic stenosis is present.
Elective Cardiac Ablation for Arrhythmias Not typically performed at LVAD implantation; best managed pre- or post-operatively.
Concomitant Left Ventricular Aneurysm Repair Rarely needed, unless aneurysm is large and poses rupture risk.
Non-Cardiac Surgeries (e.g., cholecystectomy, hernia repair, etc.) Avoid unless absolutely necessary due to increased surgical risk and bleeding.
What are signs of RV Failure?
RV failure signs (from COHN) –
MAP <55mmHg
CVP >16mmHg
SvO2 <55%
CI <2L/min/m2, significant ionotropic dependence; decreasing flows and power expenditure on LVAD despite adequate RPM/volume status
RV failure signs (from INTERMACS) –
BOTH of:
Elevated CVP, characterized by one of - CVP/RAP >16mmHg; IVC extremely dilated or lack of inspiratory variation – on Echo; Elevated JVP to at least half-way up the neck in a standing patient
Manifestation of elevated CVP sequalae by one of - Peripheral edema; Ascites or palpable hepatomegaly; Lab evidence of worsening hepatic or renal dysfunction
What are echo signs of RV Failure?
TAPSE <17
RV FAC <35%
RVEDD/LVEDD ratio > 1.0 in apical 4-chamber view suggests RV enlargement
PAPi <2
IVC dilated and non compressible, IVC diameter >2 cm, less than 50% collapse during inspiration
What are adverse events after LVAD - most common to least? Top 5.
Most common – Bleeding (especially, GI bleed)
Infection (especially, pneumonia and sepsis)
Aortic insufficiency
Thrombo-embolic events (especially, stroke)
Right-heart failure
Least common – Pump thrombosis
Most common reason for death is WITHDRAWAL OF LVAD.
Components of the Fried Frailty Phenotype score?
G-PEWW –
Grip (standardized to sex/BMI)
Physical activity/week (<383Kcal in men, <270Kcal in women)
Exhaustion (3 days/week)
Walk 15ft (standardized by sex/height)
Weight loss (>10lbs)
TAVI risk factors for futility:
A - advanced dementia; B – bedridden; C – cachexia; D – disability; E – end-organ damage
What are the adverse outcomes in obese patients with transplants and LVADs?
Poor survival, prolonged waiting time to transplant, infection, rejection, DM and CAV.
- HTx: BMI >35 decreases survival, increases infection, rejection, DM, CAV
- LVAD: BMI >35 increases TE and infection, but does not impact survival
What are the acute vasodilators that you can use for a challenge in patients with pHTN?
Nitric oxide, nitroglycerin, and sodium nitroprusside.
Do NOT use PDE-5 inhibitors (sildenafil, etc.)
Indication:
PVR > 3U, TPG > 15 mmHg, sPAP > 50 mmHg
Agents:
IV sodium nitroprusside, inhaled NO, IV Adenosine, Inhaled Iloprost, IV milrinone, IV prostagladin E1
PH reversibility defined as:
PVR <3U AND TPG <15 mmHg AND sPAP <50 mmHg while maintaining sBP >85 mmHg
Unsuccessful challenge:
2016 ISHLT – aggressively treat underlying lung disease, hospitalize and treat with IV diuretic, inotropes, and vasoactive agent (iNO, milrinone), and re-measure after 24-48 hours.
Still unsuccessful, consider for BTC for those otherwise eligible for HTx; re-evaluate after 3-6 months.
