Lvad

Ventricular Assist Devices: Evolution

1. Ventricular assist devices Raja Lahiri

2. What IS VENTRICULAR ASSIST DEVICE? A ventricular assist device (VAD) is an electromechanical device for assisting cardiac circulation, which is used either to partially or to completely replace the function of a failing heart.

3. TYPES VADs are designed to assist the right ventricle (RVAD) the left ventricle (LVAD) assist both ventricles ( BiVAD ).

4. INDICATIONS Acute cardiogenic shock Bridge to transplant (BTT) Bridge to decision Destination therapy (DT)

5. ACUTE CARDIOGENIC SHOCK Acute cardiogenic shock after AMI Post cardiotomy cardiogenic shock Cardiogenic shock from Myocarditis Refractory ventricular arrhythmias

6. Classification Short term v/s Long term Para corporeal v/s Intra corporeal Pulsatile v/s Continuous flow Full assist v/s Partial assist Assist device v/s Total artificial heart

7. Historical Perspective The first successful implantation of a left ventricular assist device was completed in 1966 by Dr. Michael E. DeBakey to a 37-year-old woman with post cardiotomy shock following aortic valve replacement. A paracorporeal (external) circuit was able to provide mechanical support for 10 days after the surgery

8. Dr. Denton Cooley reported the first successful bridging to transplant using mechanical support in 1978 The first successful implantation of a heart replacement therapy, the TAH Jarvik-7-100 was reported in 1984 The first successful long-term implantation of an artificial LVAD was conducted in 1988 by Dr. William F. Bernhard of Boston Children's Hospital Medical Center and Thermedics , Inc, which later led to the development of Heartmate

9. ‘REMATCH’ trial Rose EA, et al. “Advanced heart failure treated with continuous-flow left ventricular assist device". The New England Journal of Medicine. 2001. 345(20):1435-1443 Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure (REMATCH) trial aimed to determine the suitability of LVAD for destination therapy. In the trial, pulsatile -flow LVAD ( HeartMate XVE, Thoratec , Pleasanton, Calif.) was compared to optimal medical therapy (OMT), with the primary endpoint being all-cause mortality.

10. The trial showed that LVAD was associated with a 48% reduction in mortality as compared with OMT The survival at 1 year in the LVAD group was 52% as compared to 25% in OMT Published in 2007, the INTrEPID trial, also showed a significant survival advantage with LVAD for destination therapy in patients with inotrope -dependent heart failure, as compared to OMT In 2009, the HEARTMATE II trial reported compared the newer continuous-flow LVAD ( HeartMate II) with pulsatile -flow LVAD. The study reported that continuous-flow LVAD was associated with increased probability of 2-year survival free from disabling stroke and LVAD failure

11. AHA/ACCF Heart Failure Guidelines (2013, adapted) Mechanical circulatory support (MCS) can be considered in selected patients with stage D HFrEF with planned definitive management ( eg , cardiac transplantation) or cardiac recovery planned. (Class IIa , Level B) Nondurable MCS is reasonable as a “bridge to recovery” or “bridge to decision” for selected patients with HFrEF with acute, profound hemodynamic compromise. (Class IIa , Level B) Durable MCS is reasonable to prolong survival for selected patients with stage D HFrEF (Class IIa , Level B) Selection criteria for patients include: LVEF<25% and NYHA class III-IV despite optimal medical therapy, and either high predicted 1- to 2-year mortality ( eg , markedly reduced peak oxygen consumption and clinical prognostic scores) or dependence on continuous parenteral inotropic support

12. How does LVAD HELP THE HEART? Improves arterial blood pressure Improves end organ perfusion Decreases LVEDP as blood is directed towards LVAD Decreases intracavitory pressure leading to reduced myocardial oxygen consumption Reduces LA pressure thus decreasing pulmonary congestion and prevents right ventricular failure (Even in the presence of LVAD, if refractory RVF develops: RVAD may be used)

13. LIMITATIONS Complexity Expensive ( upto 90 lakhs ) Open surgery: morbidity & mortality Surgical expertise required

14. TYPES Short term: IABP ECMO Levitronix CentriMag Abiomed BVS 5000 & AB5000 Abiomed Impella TandemHeart

15. Long term: FIRST GENERATION: (Centrifugal & Pulsatile flow) Thoratec HeartMate XVE Thoratec paracorporeal VAD Thoratec Intracorporeal VAD SECOND GENERATION: (Axial Flow) Thoratec HeartMate II Jarvik 2000 MicroMed DeBakey Incor Berlin Heart THIRD GENERATION: (Axial Flow) VentraCor VentrAssist Terumo DuraHeart WorldHeart LevaCor Thoratec HeartMate III HeartWare CircuLite Synergy

16. IABP Kantrowitz in ‘68 Most commonly used Used in High risk PCI Post AMI- ACS Post MI- MR/VSD Cardiotomy shock Pre-op for CABG Counterpulsation Risk of vascular complications

17. ECMO For both circulatory & respiratory failure VV or VA Centrifugal pump with oxygenator High anticoagulation requirement Limited durability

18. Levitronix CentriMag Extracorporeal centrifugal pump FDA approved for upto 6 hrs Less hemolysis & chances of mechanical failure Upto 10L/min, priming vol : 31ml Routine cannulation can be used

19. ABIOMED bvs 5000 Dual chambered pneumatically driven extracorporeal pump Flow: 6L/min Initially FDA approved for post cardiotomy shock Easy to insert & manage

20. ABIOMED AB 5000 Next gen device after BVS 5000 Fully automated Vacuum asisted console Increased patient mobility Increased duration of support

21. Abiomed Impella recover lp 2.5 Minimally invasive assist device Inserted percutaneously through femoral artery upto Left ventricle 2.5L/min flow with partial support Impella recover LP 5.0 inserted upto aorta & can provide flow upto 5L/min Most commonly for high risk PCI

22. Tandem heart Percutaneously inserted Inflow through femoral vein from LA; Outflow into femoral artery Flow rates upto 4 L/min @7500rpm Easy to insert: popular in high risk PCI & post MI shock

23. THORATEC heartmate xve FDA approved both for BTT & DT Electronically vented, portable console & batteries Pusher plate technology: pulsatile flow SV=83ml, Flow 10L/min Two mode: fixed & auto In electronic failure: can be pneumatically driven with a hand pump No anticoagulation, only aspirin

24. Thoratec paracorporeal vad For Univentricular & Biventricular support Paracorporeal placement allows implantation in pt with BSA<1.5m2 Pulsatile flow: SV-65ml, max flow- 7.2L/min Requires less dissection Inflow from LA/LV Apex/RA/RV; Outflow to Aorta/ Pulm Artery

25. Thoratec intracorporeal vad Similar to paracorporeal device in applications Requires more dissection First FDA approved implantable BiVAD for BTT & post cardiotomy shock

26. THORatec heartmate ii Axial flow rotary pump Smaller, less invasive Flow 10L/min @ 6k-15k rpm Inflow: LV Apex Outflow: Ascending aorta Small pocket for housing in preperitoneal space FDA approved for BTT

27. Jarvik 2000 Electromagnetically actuated 2.5cm diameter, weight: 90gms Displacement: 25ml Flow: 7L/min @ 8k-12k rpm Actual pumping chamber in LV Can be implanted through left thoracotomy

28. Micromed debakey In collaboration with NASA Wt: 95gms Size: 3”x1.2” Flow: 10L/min Single percutaneous driveline Anticoagulation required High incidence of stroke and embolism reported FDA approved for use in children as BTT

29. Incor Berlin heart MagLev axial flow pump Wt:200gm;3cm dia Impeller magnetically levitated: hence not in contact with any other part 7L/min @ 10k rpm

30. Ventracor ventrassist Centrifugal pump with hydrolytically suspended motor No need for anticoagulation Wt:300gms, 2.5” dia 82% success as BTT

31. Terumo duraheart Magnetic Levitation technology Flow: 2-8L/min @ 1200-2400rpm In case of magnetic failure, the impella can be levitated hydrolytically

32. Worldheart levacor Magnetically levitated centrifugal pump Specially devised for pediatric age group

33. Thoratec heartmate iii Magnetically levitated centrifugal impeller Transcutaneous energy transfer system for battery charging Totally implantable

34. heartware Centrifugal pump with no mechanical bearings Wt: 145gm, SV: 45ml, Flow: 10L/min @ 2k-3k rpm Inflow cannula integrated into LV Implanted in pericardial space Single flexible 4.2mm dia driveline exits anterior abdominal wall

35. Circulite synergy Can be placed intrvascularly Inflow in LA (through subclavian vein), outflow in subclavian artery Partial support device

36. DEVICE selection Patient classification: Acute cardiogenic shock May or may not have Multi Organ Failure Neurological status may or may not be known CHF listed for heart transplantation Bridge to transplant (BTT) candidates Other CHF patients Non transplant candidates Not yet evaluated for transplant Potentially recoverable myocardium Candidates for destination therapy (DT)

37. Patients in Cardiogenic Shock Abiomed BVS 5000 Abiomed AB 5000 CentriMag BiVAD Decompresses both ventricles Restores hemodynamic stability Provides enhanced peripheral perfusion Prevents end organ dysfunction Decreases the requirement of pressors as inotropes viz. milrinone can be stopped

38. BTT FDA has approved HeartMate II for BTT Better than HM I Smaller Quieter Low incidence of infection Decreased incidence of device malfunction Bridge to recovery/decision CentriMag Can switch to long term device or explant as per need DT HeartMate XVE is the only FDA approved device for DT HM II & VentraCor VentrAssist are being evaluated Both are smaller, comfortable and long lasting

39. SURGICAL TECHNIQUE OF INSERTION Skin Incision Creation of preperitoneal pocket Mediastinal exposure Cannulation of the aorta and venous system Going on CPB Outflow graft anastomosis to ascending aorta Coring of LV, placing core sutures & inserting inflow core into LV apex De-airing the device Weaning off CPB, actuating LVAD Hemostasis & Closure

40. POST-OP Management Early post-op: Antibiotics: from pre-op to atleast 3 days post-op RHF treated with Milrinone , Dobutamine and Nitric Oxide NE or Vasopressin for vasodilator hypotension Amiodarone & Lidocaine for ventricular arrhythmias Late post-op: Early ambulation & rehabilitation Monitoring signs of infection Discharge f/b weekly follow-up for atleast a month

41. Anticoagulation: HeartMate I XVE: does not require anticoagulation HM II, VentraCor & Thoratec Intra and Para corporeal VAD: VKA + antiplatelets Anticoagulation & Antiplatelets avoided in the first 48 hrs

42. COMPLICATIONS Bleeding Platelets, FFP, Cryoprecipitate, Factor VII Infection Sepsis in 11-26% leading to 21-25% deaths Thromboembolism (7-47%) HM XVE has lowest incidence (2-3%) Device Malfunction Right Heart Failure 20% incidence; Mx : diuresis , NO, inotropes , RVAD Multisystem Organ Failure 11-29% of VAD deaths; usually pre- exisiting

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