Left Ventricular Assist Devices: Physiology, Complications and Emergencies

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1 Left Ventricular Assist Devices: Physiology, Complications and Emergencies Sara Kalantari, MD Assistant Professor of Medicine, Heart Transplant & Mechanical Circulatory Support Program University of Chicago

2 Disclosures I have no relevant financial relationships with the manufacturer(s) of any commercial product(s) and/or provider(s) of commercial services discussed in this CME activity. I do not intend to discuss an unapproved/investigative use of a commercial product/device in my presentation.

3 Learning Objectives At the end of my presentation you (the learner) will be able to: 1. Understand the physiology behind left ventricular assist devices 2. Understand the physiology behind left ventricular assist device complications 3. Manage left ventricular assist device complications such as GI bleeding, stroke, driveline infection 4. Manage an unresponsive patient with a left ventricular assist device

4 The Prevalence of Heart Failure Estimated 23 million people with HF worldwide United States: 5.8 million 3.1 million men, 2.7 million women cases diagnosed each year with over 1 million hospitalizations and 3.4 million outpatient visits The healthcare cost of HF is estimated at $39.2 billion in the United States for 2010 Prevalence of Common Cardiovascular and Lung Diseases, U.S., 2004, NHLBI report Death from specific cardiovascular, Lung and Blood Diseases, U.S., 2004 NHLBI report

5 Medical Treatment in Heart Failure Jorde UP. Cardiol Rev Mar-Apr;14(2):81-7.

6 Number of Heart Transplants Lars H. Lund et al The Journal of Heart and Lung Transplantation, Volume 34, Issue 10, 2015,

7 Fang JC. N Eng J Med Dec 3;361(23): Schwarzenegger A Cameron J. Terminator 3: Rise of the Machines 2003

Device 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 LVAD

8 The Number of LVAD BTT from the Total OHT is Increasing 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Total Adult Cardiac Transplants w Device LVAD Bridged De Novo Uriel N et al. J Heart Lung Transplant Feb;32(2):188-95

9 LVAD a New Heart Physiology

10 LVAD Physiology 10

LVAD Flow Flow through a CF-LVAD is proportional to

pressure difference across the pump Preload and/or

and/or Afterload INCREASES flow through the pump

11 LVAD Flow Flow through a CF-LVAD is proportional to the rotor speed and inversely proportional to the pressure difference across the pump Preload and/or Afterload DECREASES flow through the pump Preload and/or Afterload INCREASES flow through the pump Afterload Preload Grinstein J / Sayer G / Uriel N ISHLT

12 What are HQ curves? HQ Stands for Pressure (H = Pressure Head) and Flow (Q) Head (H) = Pressure differential across pump or delta P (ΔP) Flow (Q) = Flow through the pump 12

DIFFERENTIAL (H) AT DIFFERENT SPEEDS ΔP Aortic Pressure

pump speeds Illustrates how the pump operation may change

13 How do HQ curves relate to LVADs? HQ CURVES DEFINE HOW PUMP FLOW (Q) RELATES TO PUMP PRESSURE DIFFERENTIAL (H) AT DIFFERENT SPEEDS ΔP Aortic Pressure (AoP) Left Ventricular Pressure (LVP) Plotted for multiple pump speeds Illustrates how the pump operation may change at different speeds HQ curve characteristics and shapes are intrinsic to each pump design 13

14 Afterload sensitivity MCS term generally used to describe MCS pump flow to be responsive to changes in afterload or Mean Arterial Pressure (MAP) MCS devices cannot be exclusively sensitive to afterload, they are also dependent on preload (filling pressures) 14

15 What does afterload sensitivity mean regarding HQ curves? Afterload and Preload Sensitivity: A qualitative term describing the extent of pump flow (Q) change with respect to changing pressure high sensitivity or flat curve: small ΔP change = large flow (Q) change For any given speed, pump flow (Q) is defined by ΔP regardless of its individual afterload or preload constituents Related term Shutoff pressure Shutoff pressure is the ΔP at which flow is zero for a given speed If the ΔP is greater than the shutoff pressure, flow will be retrograde 15

16 Flat curve and steep curve FLAT HQ CURVE: Indicates the device is more sensitive to changes in afterload and preload Native contractility is represented by more pulsatile pump flow STEEP HQ CURVE: Indicates the device is less sensitive to changes in afterload and preload Native contractility is represented by less pulsatile pump flow, i.e., damped 16

17 Flat HQ curve Shutoff Pressure Flat Region In this example, a ΔP increase of 10 mmhg (either increased AoP or decreased LVP) reduces pump flow from 5 LPM to 0 LPM This is an example of a FLAT HQ curve ΔP (AoP LVP, mmhg) Increased ΔP Decreased Flow Low Flow Alarm Threshold Max Pump Flow Pump Flow (LPM) 17

18 Steep HQ curve Shutoff Pressure In this example, a ΔP increase of 10 mmhg (either increased AoP or decreased LVP) reduces pump flow from 5 LPM to 4 LPM This is an example of a STEEP HQ curve ΔP (AoP LVP, mmhg) 100g 90 Increased ΔP Decreased Flow Low Flow Alarm threshold Max Pump Flow Pump Flow (LPM) 18

19 HeartMate II Left Ventricular Assist Device: HQ curves Steep slope Pump Head (mmhg) HeartMate II LVAD H-Q Pump Flow (L/min) 12,000 11,600 11,200 10,800 10,400 10,000 9,600 9,200 8,800 8,400 8,

20 HeartWare HVAD Left Ventricular Assist Device: HQ curves Flat slope 20

HeartMate 3 Left Ventricular Assist Device: HQ curves Flat slope at lower flows Steep at higher flows Pump Head (mmhg) 160 150 140 130 120 110 100 90 80 70 60 50 40 30

21 HeartMate 3 Left Ventricular Assist Device: HQ curves Flat slope at lower flows Steep at higher flows Pump Head (mmhg) HeartMate 3 LVAD H-Q 8,000 7,500 7,000 6,500 6,000 5,500 5,000 4,500 4, , , Pump Flow (L/min) 21

22 LVAD Design 22

23 The Pumps HM II HM 3 HVAD Implant Location Chest/abdomen Pericardial Pericardial Flow Configuration Axial Centrifugal Centrifugal Impeller suspension Mechanical bearing MegLev Hybrid MegLev/ hemodynamics Weight 250gm 220gm 160gm Displaced Volume cc 75-80cc 55cc Maximum Output 10 Lpm 10 Lpm 10 Lpm Artificial Pulsatility No Yes No Thoracotomy Compatible Yes (less simple) Yes Yes What are the Critical Differences Between the Continuous Flow VAD S 23

Ventricular Device Innovation Pulsatile Technology

Design HeartMate II FDA Approved BTT 2008 DT 2010

HeartMate III Bearings FDA Approved BTT 1998 DT

24 Ventricular Device Innovation Pulsatile Technology HeartMate XVE Continuous Flow Technology: Axial Design HeartMate II FDA Approved BTT 2008 DT 2010 Continuous Flow Technology: Centrifugal Design HeartMate III Bearings FDA Approved BTT 1998 DT 2002 Bearings with stator Bearingless with Magnetic Levitation

25 HeartMate II LVAS The HeartMate II LVAS (St. Jude Medical, Inc.) is a mechanical bearing axial continuous-flow blood pump 1 Slaughter et al. Advanced Heart Failure treated with Continuous Flow Left Ventricular Assist Device. N Engl J Med Dec 16;361(23):

26 HeartWare HVAD What are the Critical Differences Between the Continuous Flow VAD S 26

27 HeartMate 3 LVAS The HeartMate 3 LVAS (St. Jude Medical, Inc.) is a centrifugal-flow, fully magnetically levitated blood pump engineered to minimize destruction of red blood cells and thrombosis Wide blood-flow passages to reduce shear stress Frictionless with absence of mechanical bearings Intrinsic Pulse designed to reduce stasis and avert thrombosis

28 Outcome HM 2 HM 3 HVAD 1 month BTT 95% BTT/DT 97% BTT 99% DT 90% 6 month BTT 89% BTT/DT 92% BTT 94% 1 year BTT 85% NA BTT 86% DT 74% - 76% DT 75% 2 years DT 61%-66% NA DT 65.1% John R et all An thor Surg 2011 Jorde UP et all JACC 2014 Netuka I et all JACC 2015 What are the Critical Differences Between the Continuous Flow VAD S 28

29 The Pumps Events/PY HM 2 HM 3 (6 Months) Bleeding Required Surgery % 0.26 GI Bleeding % 0.23 Infection Overall % 0.45 Driveline Infection % 0.29 Right Heart Failure % 0.33 Ischemic Stroke % 0.11 Hemorrhagic Stroke % 0.09 Device Thormbosis HVAD (advanced study) What are the Critical Differences Between the Continuous Flow VAD S 29

30 HM II & HM 3 Screen Presentation Title Here 30

31 HVAD Screen and Wave Form

32 LVAD Complications 32

33 Complications Advanced heart failure patients treated with continuous-flow Left Ventricular Assist Systems benefit from improved survival and quality of life 1 However, clinical outcomes are limited by infection, bleeding, neurological events, and pump malfunction (principally due to pump thrombosis) Pump thrombosis, a complication noted with the available axial 2,3 and centrifugal-flow pumps 4 is a principal component of the constellation of hemocompatibility related outcomes 1 Slaughter et al. Advanced Heart Failure treated with Continuous Flow Left Ventricular Assist Device. N Engl J Med Dec 16;361(23): Starling RC et al. Unexpected abrupt increase in left ventricular assist device thrombosis. N Engl J Med Jan 2;370(1): Kirklin JK et al. INTERMACS analysis of pump thrombosis in the HeartMate II left ventricular assist device. J Heart Lung Transplant Jan;33(1): Najjar SS. An analysis of pump thrombus events in patients in the HeartWare ADVANCE bridge to transplant and continued access protocol trial. J Heart Lung Transplant Jan;33(1):23-34.

34 Pump Thrombosis, Neurological Events, Bleeding Suspected or Confirmed Pump Thrombosis HeartMate 3 (n=151) n (%) no. of Events HeartMate II (n=138) no. of n (%) Event s RR 95% CI for RR P Value 0 (0) 0 14 (10) 18 N/A N/A < All Stroke 12 (7) (10) Hemorrhagic Stroke 4 (2) 4 8 (5) Ischemic Stroke 8 (5) 8 9 (6) Disabling Stroke 9(6) 9 5(3) Other Neurologic Events* 9 (6) 9 8 (5) Bleeding 50 (33) (39) Bleeding Requiring Surgery 15 (9) (13) Gastrointestinal Bleeding 24 (15) (15) No Pump Thrombosis in the HeartMate 3 group Similar Stroke and Bleeding rates in both groups 1 Mehra MR, Naka Y, Uriel N et al. N Engl J Med Feb 2;376(5):

35 Device Thrombosis 35

36 Device Thrombosis HM II Device thrombosis HVAD Device Thrombosis. J Heart Lung Transplant Jan;33(1):51-9 UrielN/Jorde UP et al. JACC 2012, 60(18): Uriel N/Jorde UP et al. J Heart Lung Transplant Jan;33(1):51-9. Jorde UP/Uriel N et al, JACC HF 2015 Courtesy of Dr Shmitto

37 NEJM MONTHs

PREVENT Recommendations Surgical Recommendations 1 Medical Recommendations 2 Anticoagulation In patients without persistent bleeding, bridge with heparin; goal PTT of 40-45 sec (48 hours); PTT of

38 PREVENT Recommendations Surgical Recommendations 1 Medical Recommendations 2 Anticoagulation In patients without persistent bleeding, bridge with heparin; goal PTT of sec (48 hours); PTT of sec (96 hours). Initiate warfarin within 48 hours; Target INR: Antiplatelet Initiate ASA therapy ( mg daily), 2-5 days post HMII implantation. Pump Speed Maintain > 9000 RPM and Avoid < 8600 RPMs. Blood Pressure Maintain mean arterial pressure (MAP) < 90 mmhg. References: 1 Adamson RM, Mangi AA, Kormos RL, J Card Surg Mar;30(3): Klodell CT, Massey HT, Adamson RM. J Card Surg Oct;30(10): Maltaise S et al, ISHLT 2016

PREVENT: Pump Thrombosis Events; 300 Subjects received 313 Devices over 6 months

4%) Confirmed: 15 (4.8%) Not Confirmed: 5 (1.6%) Outcome: Pump Exchange: 11 (3.

39 PREVENT: Pump Thrombosis Events; 300 Subjects received 313 Devices over 6 months 18 subjects (6.0%) experienced 20 suspected pump thrombosis events (6.4%) Confirmed: 15 (4.8%) Not Confirmed: 5 (1.6%) Outcome: Pump Exchange: 11 (3.5%) Urgent Transplantation: 3 (1.0%) Patient Ongoing: 1 (0.3%) Outcome: Pump Exchange: 2 (0.6%) (No thrombus upon explant analysis) Patient Death: 1 (0.3%) (No thrombus upon explant analysis) Patient Ongoing: 2 (0.6%) Maltais S et al, JHLT 2017;36:1-12

40 Bleeding 40

41 High Frequency of Bleeding? Uriel et al. Jour Am Col of Card. 2010;56(15):

42 Bleeding and AVMs in Cardiovascular Disease Aortic Stenosis and Von Willebrand Factor Deficiency Heyde, NEJM 1954 Sadler, NEJM 2003;394:4

43 Ventricular Arrhythmias 43

44 Ventricular Arrhythmias: Initially can be Well Tolerated Garan AR / Uriel N et al. J Am Coll Cardiol May 2

45 VA post-lvad is associated with more readmissions and higher morbidity Pain/trauma of ICD shocks RV failure From VA: incidence of RV failure 45% in patients with early VA (versus 23% without) in one cohort From shocks: multiple ICD shocks associated with dramatically higher incidence of acute RV failure, compared with ATP alone or single shock (50 v. 4%) Need for RVAD, inhaled pulmonary vasodilator, inotrope Garan AR / Uriel N. J Heart Lung Transplant 2015; 34(12):

46 VA POST-LVAD IS ASSOCIATED WITH HIGHER RISK OF DEATH Probability of Death VT/VF Follow-up years No VT/VF No VT/VF VT/VF Yoruk A et al. Heart Rhythm 2016;13:1052-6

Follow-up years No VT/VF 108 84 49 24 VT/VF 41

47 VA post-lvad is associated with higher risk of death Probability of Death VT/VF No VT/VF Follow-up years No VT/VF VT/VF Yoruk A et al. Heart Rhythm 2016;13:

48 Risk for Early VT Garan AR / Uriel N. JACC 2013; 61(25):

49 INTRACTABLE VT IS NOT TOLERATED INDEFINITELY BUN Cr AST ALT

50 Can We Predict Post-op VA? Early Events Often Lack a Clear Reversible Precipitant Electrolyte Ischemia Suction Inotrope None Garan AR / Uriel N. J Heart Lung Transplant 2015; 34(12): LVAD arrhythmias 50

51 Patient Presentation 64 y/o male ICM s/p HMII 6/2012 Presented to the ED with melena, lethargy and multiple ICD shocks

52 PMH Coronary artery disease Hx of complete heart block HeartMate II LVAD

53 Histories Allergies: NKDA Family History: Father: CVA Brothers: DM Social History: EtOH: Occasional Tobacco: Smoked for 40-45y, quit IVDU: Denies

54 Home Medication List Indication Heart History Medication ASA 81 mg PO Daily Metoprolol Succinate 25 mg PO BID Pravastatin 20 mg PO daily Warfarin 1.5 mg PO Qmonday Warfarin 2 mg PO QTuWThFSaSu GERD/GI Bleed Hx Pain Pantoprazole 40 mg PO daily APAP 650 mg PO Q6H PRN Oxycodone 5 mg PO Q6H PRN Constipation Supplements Docusate 200 mg PO daily PRN Multivitamin PO daily Vitamin D 1000 IU PO daily Magnesium Oxide 400 mg PO BID

55 Vitals Admission to ED Weight: 86.5 kg Height: 6 1 BMI: 25.2 BP=MAP: 61 Temp: 36.7 RR: 20

56 Labs: CBC WBC Hgb Hct MCV Plt LABS: BMP Na K Cl CO2 SCr BUN

57 Labs: LFTs AST ALT Alk Phos Bili Albumin LABS: COAGULATION PT INR aptt

58 How do we manage this patient? A. Trend hemoglobin, no need to treat VT/VF as patient is stable and supported with LVAD B. Turn down the LVAD speed, give blood and cardioversion C. Turn up the LVAD speed, give blood and cardioversion D. Start chest compressions

59 Patient Case Continued There were multiple ineffective ICD shocks for both VT and VF noted on device interrogation LVAD speed was turned down from 9400 to 9000 rpm Given IVF followed by 2 units PRBC He required defibrillation with simultaneous internal and external shock under sedation After hemodynamic optimization, DFT remained greater than maximum programmable ICD output He underwent VT ablation and addition of a subcutaneous coil. Post-revision DFT was 36J.

60 Treatment Options for VT Storm Defined as 3 or more sustained episodes of VT/VF or appropriate shocks within 24 hrs Risk factors include: Precipitants include: Acute ischemia Worsening CHF Hypokalemia Hypomagnesemia Arrhythmogenic drugs Hyperthyroidism Infection Fever Bleeding RV Failure Suction Event

61 Cardiac Arrest in LVAD 61

62 Assessment of perfusion Flow and Perfusion and not synonymous The LVAD can be flowing but there may be inadequate perfusion Automated BP cuffs are not a reliable marker of perfusion. Doppler blood pressure is the preferred BP method in LVAD patients Assess skin color, capillary refill Capnography and end-tidal CO2 (PETCO2) Normal PETCO mmhg PETCO2 < 20 mmhg in an unconscious pulseless patient is a marker of inadequate perfusion

63 Unresponsive Patient When terminal rhythms occur audible pump sounds heard and dopplerable arteries or PETCO2 > 20 mmhg, use only: Electrical cardioversion/defibrillation, pacing Vasoagonists (epinephrine etc ) When no audible pump sounds are heard and/or non-dopplerable arteries or PETCO2 < 20 mmhg, compressions may be necessary If trained to do so: Ensure connections to LVAD are secure Perform controller exchange Place on wall power Place on batteries if short to shield is suspected The major risk with chest compressions is dislodgement of: The device The outflow cannula Int J Cardiol Oct 15;168(6): Resuscitation. 2014;85(5): doi:

64 Treatment algorithm for unresponsive LVAD patient Circulation (24):e

65 Eur Heart J: Acute Cardiovasc Care (8):522-6.

66 Vascular collapse with normal LVAD function At times, perfusion to vital organs (assessed by PETCO2 or arterial Doppler) can be insufficient despite normal LVAD function DDx includes: RV Failure Tamponade Tension pneumothorax Chest compressions should be instituted in this setting

67 Abdominal Compressions One case study of performed abdominal resuscitation in an LVAD patient successfully Abdominal compressions can maintain a coronary perfusion pressure of 15 mm Hg At ROSC, care should be taken to support the ischemic RV J Cardiothorac Surg 2011; 6:91.

68 RV Compression The VAD Journal Vol 3, Article 9

69 Conclusion History of LVADs LVAD physiology LVAD management LVAD complications and their management

EMS: Care of the VAD Patient. Brittany Butzler BSN RN VAD Coordinator Froedtert and the Medical College of WI

EMS: Care of the VAD Patient. Brittany Butzler BSN RN VAD Coordinator Froedtert and the Medical College of WI EMS: Care of the VAD Patient Brittany Butzler BSN RN VAD Coordinator Froedtert and the Medical College of WI Disclosure No relevant financial relationships by planners or presenters Left Ventricular Assist