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Left ventricular assist device (LVAD)


Mason Shu
Carolyn Glass, M.D., Ph.D.

Last staff update: 20 September 2024 (update in progress)

Copyright: 2023-2024, PathologyOutlines.com, Inc.

PubMed Search: Left ventricular assist device (LVAD)

Mason Shu
Carolyn Glass, M.D., Ph.D.
Table of Contents
Definition / general | Essential features | Terminology | ICD coding | Epidemiology | Sites | Pathophysiology | Etiology | Clinical features | Laboratory | Prognostic factors | Case reports | Treatment | Gross images | Videos | Sample pathology report | Board review style question #1 | Board review style answer #1 | Board review style question #2 | Board review style answer #2
Cite this page: Shu M, Glass C. Left ventricular assist device (LVAD). PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/heartLVAD.html. Accessed December 26th, 2024.
Definition / general
  • Left ventricular assist device (LVAD) is a mechanical pump flow device that helps the left ventricle pump blood to the rest of the body in patients with heart failure, which affects > 6 million Americans (Circulation 2020;141:e139)
  • LVADs are standard of care for medically refractory stage D heart failure as either bridge to transplant or destination therapy (long term or indefinite therapy)
Essential features
  • Serves as a bridge for patients waiting for a heart transplant
  • LVADs not only improve survival but also quality of life; patients experience a significant reduction in New York Heart Association functional class (N Engl J Med 2019;380:1618)
  • LVADs improve survival and quality of life for patients with stage D heart failure, defined as the presence of refractory symptoms after optimal medical, surgical and device therapies (J Card Fail 2015;21:519)
  • First generation LVADs were based on pulsatile flow
  • Subsequent LVADs use continuous flow instead of pulsatile flow, which allows for engineering modifications including smaller size and improved long term survival (J Heart Lung Transplant 2013;32:141, N Engl J Med 2009;361:2241)
Terminology
  • Durable mechanical circulatory support device (MCS)
  • HeartMate II™ (HMII), HeartMate 3™ (HM3)
  • Other ventricular assist devices (VAD)
    • Right ventricular assist device (RVAD)
    • Biventricular assist device (BiVAD); when both LVAD and RVAD are implemented
ICD coding
  • ICD-10: Z95.811 - presence of heart assist device
Epidemiology
  • Between June 2006 and December 2018, nearly 25,000 adult patients received mechanical circulatory support devices; > 2,000 LVADs are still being implanted annually
  • > 580,000 individuals have stage D heart failure in the U.S. with a 1 year survival rate ranging from 6% to 25% (N Engl J Med 2001;345:1435)
  • Men are more likely to receive LVADs due to the increased risk of developing heart failure (BMJ Glob Health 2017;2:e000298)
  • 52% of LVAD recipients are in some form of cardiogenic shock during time of implantation (J Am Coll Cardiol 2022;79:1092)
  • Heart transplant waitlist mortality decreased from 14.6 deaths per 100 waitlist years in 2005 to 9.7 deaths in 2015, due to improvements in medical therapy guidelines, organ donor systems and continuous flow LVADs used as a bridge to transplant (Am J Transplant 2018;18:291)
Sites
  • Heart: left ventricle
  • Left ventricular core (base of the heart)
Pathophysiology
  • Patients with heart failure present with low or reduced ejection fraction (HFrEF: EF < 40%) and also systolic heart failure (Eur Heart J 2016;37:2129)
  • HFrEF hearts undergo eccentric remodeling accompanied with ventricular chamber dilatation, volume overload and activation of the renal angiotensin system (Cardiovasc Diagn Ther 2021;11:263)
  • Patients may present with preserved ejection fraction (HFpEF: EF > 50%) and also diastolic heart failure or mid range ejection fraction (HFmrEF: EF 40 - 49%) (Eur Heart J 2016;37:2129)
  • HFpEF hearts show concentric remodeling accompanied with ventricular hypertrophy, impaired ventricular relaxation or filling, increased ventricular stiffness and elevated filling pressure (Cardiovasc Diagn Ther 2021;11:263)
Etiology
  • Common etiologies associated with HFrEF / systolic dysfunction patients include coronary heart disease (myocardial infarction), valvular heart disease volume overload (aortic stenosis, mitral regurgitation) or uncontrolled hypertension, arrhythmias, inflammatory diseases, idiopathic cardiomyopathy and alcoholic / toxic cardiomyopathy (Cardiovasc Diagn Ther 2021;11:263)
  • Common etiologies associated with HFpEF / diastolic dysfunction include obesity, hypertension, atrial fibrillation, diabetes mellitus, volume overload / pressure overload, hypertrophic cardiomyopathy, restrictive cardiomyopathy, amyloid (Cardiovasc Diagn Ther 2021;11:263)
Clinical features
  • Complications after LVAD implantation include (J Am Heart Assoc 2022;11:e027251, J Clin Med 2022;11:2575)
    • Bleeding (Ann Thorac Surg 2021;111:778)
      • Common in the beginning of the postoperative period (0 - 90 days)
      • Nearly 33% of patients experience 1 episode of bleeding within 1 year of operation; gastrointestinal (GI) bleeding is most common, occurring in 60% of LVAD patients (Hematology Am Soc Hematol Educ Program 2019;2019:88)
    • Infection (Am J Cardiol 2018;122:1021, J Heart Lung Transplant 2019;38:721)
      • Common where driveline exits the abdominal wall
      • ~40% of patients experience major infection
      • Correct driveline management can mitigate infection
      • Most VAD specific infections are localized to the driveline
      • VAD specific infections may affect the LVAD pump, cannula or pocket
      • VAD related infections include endocarditis, bloodstream infections and mediastinitis from sternal wound or pocket infection
      • Non‐VAD infections include pneumonia, urinary tract infection, cholecystitis and Clostridium difficile infection
    • Thrombosis (typically around the inflow cannula) (ASAIO J 2016;62:375, N Engl J Med 2019;380:1618)
      • Continuous innovations lower the risk of thrombosis / need for LVAD exchange (HM3 design associated with less friction, increased intrinsic pulsatility, decreased shear stress and stasis of blood)
      • MOMENTUM 3 (multicenter study of MagLev technology in patients undergoing mechanical circulatory support therapy with HeartMate 3) trial compared HM3 to the HMII, incidence of LVAD thrombosis at 2 years was 1.4% in HM3 versus 13.9% in HMII, p < 0.001
      • < 10% of patients experience pump thrombosis
    • Neurologic events / strokes (N Engl J Med 2017;376:451, Circ Heart Fail 2012;5:241)
      • Both ischemic and hemorrhagic strokes range from 5% to 30%
      • ~13% of patients experience a stroke within 1 year of implantation (J Am Coll Cardiol 2022;79:1092)
      • Ischemic strokes are likely caused by thromboembolism
      • Hemorrhagic strokes can occur from elevated blood pressure (BP), high velocity intracranial flow or hemorrhagic conversion from thromboembolic strokes
    • Right heart failure (J Am Coll Cardiol 2021;78:2294, J Heart Lung Transplant 2017;36:50)
      • Occurs in 53% of patients
      • Divided into 3 phases
        • Early acute: RVAD is necessary at the time of LVAD implantation
        • Early postimplant: RVAD is necessary within 30 days of LVAD implantation
        • Late stage: RVAD is necessary after 30 days of LVAD implantation
Laboratory
  • Divide into routine monitoring and labs to assess complications
  • Recommended tests
    • Technical: power source maintenance (batteries, power module), daily self test, dressing changes
    • Hematocrit and hemoglobin to assess bleeding
      • Lactate dehydrogenase (LDH)
      • Haptoglobin
      • Free hemoglobin
      • Coagulation tests (e.g., complete blood count [CBC])
      • Electrocardiogram (EKG): assess for arrhythmia
      • Computed tomography (CT): assess for deep space soft tissue infection
  • Reference: J Clin Med 2023;12:5216
Prognostic factors
  • Landmark REMATCH (randomized evaluation of mechanical assistance for the treatment of congestive heart failure) trial, 1 year survival with the first generation pulsatile HeartMate XVE LVAD was 52% compared with 25% in the medical therapy group (P = 0.002) (N Engl J Med 2001;345:1435)
  • MOMENTUM 3 trial demonstrated survival with HM3 LVAD reached 79% at 2 years (N Engl J Med 2019;380:1618)
  • Survival (data from 2015 - 2019) (JACC Heart Fail 2022;10:948)
    • 1 year survival: 82.3%
    • 2 year survival: 73.1%
    • Median survival duration: > 4.5 years
  • Unfavorable risk factors (J Am Coll Cardiol 2022;79:1092)
    • Old age
    • Obesity
    • Poor nutritional status
    • Previous cardiac surgery
    • Lower serum sodium
    • Higher blood urea nitrogen (BUN)
    • Small left ventricular size
    • Right atrial pressure to pulmonary capillary wedge pressure ratio > 0.6
Case reports
Treatment
Gross images

Contributed by Carolyn Glass, M.D., Ph.D.
Left ventricular apex with attached LVAD

Left ventricular apex with attached LVAD

LVAD pump and attachments

LVAD pump and attachments

Videos

Overview of the HeartMate II

Sample pathology report
  • Left ventricular apex, VAD core, excision:
    • Replacement fibrosis consistent with healed ischemic injury (see comment)
    • Myocyte hypertrophy, mild to focally moderate
    • Interstitial fibrosis, mild
    • Endocardial fibrosis, mild
    • Myocyte vacuolization suggestive of chronic ischemic injury, focal
    • Comment: No histologic evidence of amyloid, myocarditis, granulomatous inflammation, myocyte disarray, extensive adipocytic infiltration, iron deposition or acute infarction.

  • LVAD:
    • Inflow cannula: a 5.5 x 5.0 cm gray metal medical device with connected outflow cannula tubes is present protruding from the apex of the heart; the device is inscribed with manufacturer number "X"
    • Outflow cannula: a 19.4 cm in length by 1.6 cm in width outflow cannula consisting of ribbed Dacron material is present; there is a 13.7 cm in length by 1.5 cm in width ribbed impression overlying the right aspect of the heart, consistent with the outflow tract
Board review style question #1
 


Which of the following is the most common complication in left ventricular assist device (LVAD) patients?

  1. Bleeding
  2. Infection
  3. Pump thrombosis
  4. Strokes
Board review style answer #1
A. Bleeding is the most common complication in LVAD patients. ~60% of patients experience GI bleeding. Answer C is incorrect because pump thrombosis is a less common complication (~14%). Answer D is incorrect because strokes are also a less common complication (~12 - 28%). Answer B is incorrect because infection is the second most common complication (~40%).

Comment Here

Reference: Left ventricular assist device (LVAD)
Board review style question #2
A 26 year old White man recently received a left ventricular assist device (LVAD) implantation after suffering from sudden heart failure. The patient reported that he had been keeping a healthy diet ever since he suffered a non-ST elevation myocardial infarction at age 19. Which of the following factors heavily contributed to the development of stage D heart failure in the patient?

  1. Age
  2. Gender
  3. Nutrition
  4. Previous cardiac surgery
Board review style answer #2
D. Previous cardiac surgery. Patients who underwent previous cardiac surgery are more susceptible to heart failure than those without a previous history. Answer A is incorrect because the patient is relatively young. Answer B is incorrect because at a young age, gender does not seem to be a contributing factor. Answer C is incorrect because the patient had been eating properly.

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Reference: Left ventricular assist device (LVAD)
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