Clinical management of continuous-flow left ventricular assist devices in advanced heart failure

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Continuous-flow left ventricular assist devices (LVAD) have emerged as the standard of care for advanced heart failure patients requiring long-term mechanical circulatory support. Evidence-based clinical management of LVAD-supported patients is becoming increasingly important for optimizing outcomes. In this state-of-art review, we propose key elements in managing patients supported with the new continuous-flow LVADs. Although most of the presented information is largely based on investigator experience during the 1,300-patient HeartMate II clinical trial, many of the discussed principles can be applied to other emerging devices as well. Patient selection, pre-operative preparation, and the timing of LVAD implant are some of the most important elements critical to successful circulatory support and are principles universal to all devices. In addition, proper nutrition management and avoidance of infectious complications can significantly affect morbidity and mortality during LVAD support. Optimizing intraoperative and peri-operative care, and the monitoring and treatment of other organ system dysfunction as it relates to LVAD support, are discussed. A multidisciplinary heart failure team must be organized and charged with providing comprehensive care from initial referral until support is terminated. Preparing for hospital discharge requires detailed education for the patient and family or friends, with provisions for emergencies and routine care. Implantation techniques, troubleshooting device problems, and algorithms for outpatient management, including the diagnosis and treatment of related problems associated with the HeartMate II, are discussed as an example of a specific continuous-flow LVAD. Ongoing trials with other continuous-flow devices may produce additional information in the future for improving clinical management of patients with these devices.

Section snippets

Table of Contents

  • I

    Introduction and Overview of Continous-flow Left Ventricular Assist SystemsS2

    • I.A

      Continuous-Flow LVASsS3

  • II

    Patient Selection and Preoperative Considerations S4

    • II.A

      Patient Selection for LVAD Support: Illness Assment for Operative RiskS4

    • II.B

      Patient Mortality Risk for Undergoing LVAD ImplantationS5

      • II.B.1

        Overall Risk Factors for Operative MortalityS6

      • II.B.2

        Obesity ParadoxS7

      • II.B.3

        Assessment of Right Ventricular FunctionS7

    • II.C

      Preoperative Assessment and OptimizationS8

  • III

    Intraoperative ConsiderationsS12

    • III.A

      Managing Valvular Heart DiseaseS13

      • III.A.1

Introduction and overview of continuous-flow left ventricular assist systems

Key Points

Continuous-flow left ventricular assist systems are new-generation devices with a number of major advantages over previous pulsatile technology:

  • Continuous-flow, rotary blood pumps eliminate the need for a blood pumping chamber and volume compensation.

  • A lighter, smaller pump is better suited for patients with a smaller body size.

  • Simple designs include only 1 internal moving part, the rotor, and no internal valves. This affords markedly enhanced device durability.

  • They are silent in

Patient selection and preoperative considerations

Key Points

  • The highest risk of death after LVAD implant is before hospital discharge. Thus, patient selection and the timing of implant are two of the major determinants of success.

  • Key selection criteria include assessment of the patient's severity of illness and ability to successfully undergo the implant procedure.

  • The trend at many centers is toward earlier use of a LVAD to avoid progressive end-organ dysfunction.

  • Pre-implant optimization of comorbid conditions is very important in minimizing

Intraoperative considerations

Key Points

  • Moderate to severe aortic insufficiency and mitral stenosis must be corrected during LVAD implant.

  • Inflow cannulas must be directed posteriorly toward the mitral valve. Obstruction may result if the cannula is directed or angled toward the septum or free wall or due to changes in position as the LV chamber size is reduced over time.

  • Proper placement of the percutaneous lead is of utmost importance for long-term prevention of infection and damage to wires. Tunnel the percutaneous lead to

Post-operative patient management

Key Points

  • A patient's RV function can be affected by pump speed. Avoid setting the pump speed too high or too low.

  • To avoid severe post-operative bleeding, anti-coagulation should be completely reversed after CPB. Routine use of heparin is not indicated immediately after the LVAD is implanted. Patients are usually anti-coagulated with warfarin and anti-platelet agents (aspirin) when they are able to take oral medications.

  • Mean arterial blood pressure should be maintained between 70 and 80 mm Hg

Post-operative device management

Key Points

  • Continuous-flow LVADs do not contain valves. If the pump stops, there may be back flow that can have severe consequences (similar to aortic insufficiency). Avoid power interruption or inadvertent power lead disconnection that would lead to loss of support.

  • Continuous-flow pumps can generate large negative pressures at the pump inlet, which may result in septal shift or ventricular collapse. Consequently, pump-speed optimization and device monitoring present unique challenges compared

Diagnosing and managing post-operative complications

Key Points

  • Perform physical examinations and laboratory testing regularly throughout LVAD support.

  • Teach patients and family member(s)/caregiver(s) how to identify and respond to signs and symptoms of the most common problems.

  • Echocardiography is very useful in diagnosing problems with the patient-pump interface. Echocardiography can assess:

    • Adequacy of pump speed and support by determining ventricular size.

    • Valvular function.

    • Inflow and outflow abnormalities.

  • Left and right-heart catheterization may

Outpatient management

Key Points

  • Successful long-term LVAD support depends on comprehensive care from a multidisciplinary team, including the patient and his or her family member(s)/caregiver(s).

  • Effective patient education and support are key components of successful outpatient support.

  • The target INR for patients receiving the HeartMate II is 1.5 to 2.5 with warfarin therapy, and aspirin at 81 to 325 mg daily for anti-platelet therapy.

  • Stabilize the INR before discharge from the hospital.

  • Over-anti-coagulation should

Troubleshooting

As has been described, each LVAS provides a number of parameters that can be used to monitor patient and pump conditions specific to each device. The authors' experience in the clinical trial with the HeartMate II LVAS has been used to write this chapter specifically for patients with that device. These parameters and their significance in troubleshooting are listed in Table 14.

Pump operating parameters are not surrogates for monitoring the patient's clinical status. The changes in all

Results from completed clinical trials

The first continuous-flow LVAD to complete FDA clinical trials for BTT and for DT is the HeartMate II. Other devices are in ongoing trials and results will be published after those trials are completed. The BTT clinical trial for the HeartMate II resulted in FDA market approval in April 2008. Of the 489 patients in the BTT trial, the results in the initial 133 patients were published,7 and an 18 month follow-up analysis has been completed in 281 patients.8 The Kaplan-Meier survival at 12 months

Disclosure Statement

This supplement was supported by Thoratec.

The authors disclose the following: Dr Slaughter, grant support from Thoratec and HeartWare; Dr Pagani, grant support from Terumo, HeartWare, and Thoratec; Dr Rogers, consulting fees and grant support from Thoratec; Dr Miller, grant support and paid speaking from Thoratec; Dr Sun, consulting fees from Thoratec, ABIOMED, HeartWare, CardioMEMS, and Sunshine Heart; Dr Russell, consulting fees and grant support from Thoratec; Dr Starling, consulting fees

References (115)

  • K. Holdy et al.

    Nutrition assessment and management of left ventricular assist device patients

    J Heart Lung Transplant

    (2005)
  • K.L. Lockard et al.

    Lack of improvement in prealbumin at two weeks predicts a poor outcome after mechanical circulatory support

    J Heart Lung Transplant

    (2009)
  • O.H. Frazier et al.

    Multicenter clinical evaluation of the HeartMate vented electric left ventricular assist system in patients awaiting heart transplantation

    J Thorac Cardiovasc Surg

    (2001)
  • D.J. Farrar et al.

    Preoperative and postoperative comparison of patients with univentricular and biventricular support with the Thoratec ventricular assist device as a bridge to cardiac transplantation

    J Thorac Cardiovasc Surg

    (1997)
  • J.R. Fitzpatrick et al.

    Risk score derived from pre-operative data analysis predicts the need for biventricular mechanical circulatory support

    J Heart Lung Transplant

    (2008)
  • J.C. Matthews et al.

    The right ventricular failure risk score a pre-operative tool for assessing the risk of right ventricular failure in left ventricular assist device candidates

    J Am Coll Cardiol

    (2008)
  • S. Schenk et al.

    Duration of inotropic support after left ventricular assist device implantation: risk factors and impact on outcome

    J Thorac Cardiovasc Surg

    (2006)
  • S. Haj-Yahia et al.

    Bridging patients after salvage from bridge to decision directly to transplant by means of prolonged support with the CentriMag short-term centrifugal pump

    J Thorac Cardiovasc Surg

    (2009)
  • D.J. Farrar

    The Thoratec ventricular assist device: a paracorporeal pump for treating acute and chronic heart failure

    Semin Thorac Cardiovasc Surg

    (2000)
  • J.R. Fitzpatrick et al.

    Early planned institution of biventricular mechanical circulatory support results in improved outcomes compared with delayed conversion of a left ventricular assist device to a biventricular assist device

    J Thorac Cardiovasc Surg

    (2009)
  • C.T. Klodell et al.

    Effect of sildenafil on pulmonary artery pressure, systemic pressure, and nitric oxide utilization in patients with left ventricular assist devices

    Ann Thorac Surg

    (2007)
  • S.E. Sandner et al.

    Renal function and outcome after continuous flow left ventricular assist device implantation

    Ann Thorac Surg

    (2009)
  • J. Butler et al.

    Relationship between renal function and left ventricular assist device use

    Ann Thorac Surg

    (2006)
  • K.D. Aaronson et al.

    Patient selection for left ventricular assist device therapy

    Ann Thorac Surg

    (2003)
  • A.J. Boyle et al.

    Low thromboembolism and pump thrombosis with the HeartMate II left ventricular assist device: analysis of outpatient anti-coagulation

    J Heart Lung Transplant

    (2009)
  • O. Reinhartz et al.

    Importance of preoperative liver function as a predictor of survival in patients supported with Thoratec ventricular assist devices as a bridge to transplantation

    J Thorac Cardiovasc Surg

    (1998)
  • B. Radovancevic et al.

    End-organ function in patients on long-term circulatory support with continuous- or pulsatile-flow assist devices

    J Heart Lung Transplant

    (2007)
  • G.V. Letsou et al.

    Continuous axial-flow left ventricular assist device (Jarvik 2000) maintains kidney and liver perfusion for up to 6 months

    Ann Thorac Surg

    (2003)
  • T.E. Warkentin et al.

    Heparin-induced thrombocytopenia in patients with ventricular assist devices: are new prevention strategies required?

    Ann Thorac Surg

    (2009)
  • R.L. Kormos et al.

    Pre-VAD implant risk factors influence the onset of adverse events (AEs) while on VAD

    J Heart Lung Transplant

    (2009)
  • J.O. Mudd et al.

    Fusion of aortic valve commissures in patients supported by a continuous axial flow left ventricular assist device

    J Heart Lung Transplant

    (2008)
  • J.C. Matthews et al.

    Aortic insuffciency—trends over time in LVAD supported patient

    J Heart Lung Transplant

    (2009)
  • D. Haghi et al.

    Aortic regurgitation during left ventricular assist device support

    J Heart Lung Transplant

    (2007)
  • S.J. Park et al.

    Management of aortic insufficiency in patients with left ventricular assist devices: a simple coaptation stitch method (Park's stitch)

    J Thorac Cardiovasc Surg

    (2004)
  • J.C. Stringham et al.

    Patch closure of the aortic anulus in a recipient of a ventricular assist device

    J Thorac Cardiovasc Surg

    (2000)
  • V. Rao et al.

    Surgical management of valvular disease in patients requiring left ventricular assist device support

    Ann Thorac Surg

    (2001)
  • C.M. Feldman et al.

    Management of aortic insufficiency with continuous flow left ventricular assist devices: bioprosthetic valve replacement

    J Heart Lung Transplant

    (2006)
  • J. Butany et al.

    Early changes in bioprosthetic heart valves following ventricular assist device implantation

    Int J Cardiol

    (2007)
  • K. Nakashima et al.

    Off-pump replacement of the INCOR implantable axial-flow pump

    J Heart Lung Transplant

    (2009)
  • O.H. Frazier et al.

    Initial experience with non-thoracic, extraperitoneal, off-pump insertion of the Jarvik 2000 Heart in patients with previous median sternotomy

    J Heart Lung Transplant

    (2006)
  • B.C. Sun et al.

    Placement of long-term implantable ventricular assist devices without the use of cardiopulmonary bypass

    J Heart Lung Transplant

    (2008)
  • J.G. Augoustides et al.

    Pro: inhaled prostaglandin as a pulmonary vasodilator instead of nitric oxide

    J Cardiothorac Vasc Anesth

    (2005)
  • C.J. De Wet et al.

    Inhaled prostacyclin is safe, effective, and affordable in patients with pulmonary hypertension, right heart dysfunction, and refractory hypoxemia after cardiothoracic surgery

    J Thorac Cardiovasc Surg

    (2004)
  • M.L. Dickstein

    Con: inhaled prostaglandin as a pulmonary vasodilator instead of nitric oxide

    J Cardiothorac Vasc Anesth

    (2005)
  • A.J. Tector et al.

    Transition from cardiopulmonary bypass to the HeartMate left ventricular assist device

    Ann Thorac Surg

    (1998)
  • I.D. Gregoric et al.

    Clinical experience with sternotomy versus subcostal approach for exchange of the HeartMate XVE to the HeartMate II ventricular assist device

    Ann Thorac Surg

    (2008)
  • S. La Francesca et al.

    Replacement of a malfunctioning HeartMate II left ventricular assist device in a 14-year-old after a sudden fall

    J Heart Lung Transplant

    (2006)
  • A.J. Lodge

    Clinical experience with sternotomy versus subcostal approach for exchange of the HeartMate XVE to the HeartMate II ventricular assist deviceInvited commentary

    Ann Thorac Surg

    (2008)
  • G.V. Letsou et al.

    Is native aortic valve commissural fusion in patients with long-term left ventricular assist devices associated with clinically important aortic insufficiency?

    J Heart Lung Transplant

    (2006)
  • R. John et al.

    Low thromboembolic risk for patients with the HeartMate II left ventricular assist device

    J Thorac Cardiovasc Surg

    (2008)
  • Cited by (0)

    Conflict of Interest: See Disclosure Statement on page S36.

    Drs. Slaughter, Pagani, Rogers, Miller, Sun, Russell, and Starling contributed equally to this article

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