2014) 247.e13e247.e15 www.onlinecjc.ca

Canadian Journal of Cardiology 30 (

Case Report

Left Ventricular Assist Device Outflow Graft DisconnectionHadi Daood Toeg, MD, MSc, Talal Al-Atassi, MD, Mark Cleland,

Marc Ruel, MD, MPH, FRCSC, and Munir Boodhwani, MD, MMSc, FRCSCDivision of Cardiac Surgery, University of Ottawa Heart Institute, Ottawa, Ontario, Canada

ABSTRACTAlthough serious complications are becoming more rare withcontinuous-flow left ventricular assist devices such as the Heartmate II(Thoratec Corp, Pleasanton, CA), this case series discusses 2 patientswith symptoms of bleeding and syncopal ventricular tachycardiaassociated with an outflow graft bend relief disconnection, which canbe diagnosed by simple chest roentgenography.

Received for publication July 30, 2013. Accepted October 30, 2013.

Corresponding author: Dr Munir Boodhwani, 40 Ruskin Street, OttawaK1Y 4W7, Ontario, Canada. Tel.: þ1-613-761-4720; fax: þ1-613-761-4713.

E-mail: mboodhwani@ottawaheart.caSee page 247.e14 for disclosure information.

0828-282X/$ - see front matter � 2014 Canadian Cardiovascular Society. Publishehttp://dx.doi.org/10.1016/j.cjca.2013.10.022

R�ESUM�EBien que les complications s�erieuses li�ees aux dispositifs d’assist-ance ventriculaire gauche (DAVG) à d�ebit continu comme leHeartmate II (Thoratec Corp, Pleasanton, CA) soient plus rares,cette s�erie de cas consiste en 2 patients ayant des symptômesd’h�emorragie et de tachycardie ventriculaire syncopale secondairesà la disconnection du greffon d’�ejection redresseur, qui peuventêtre diagnostiqu�ees par une simple radiologie diagnostique duthorax.

Therapeutic options in selected patients with end-stage heart and lower gastrointestinal endoscopies were performed, and

failure include the use of a continuous-flow left ventricularassist device (LVAD).1 Although these second-generationdevices have fewer complications, early diagnosis and man-agement can be challenging when they occur.2 The mostcommon LVAD device used is the Heartmate II (HM II;Thoratec Corp, Pleasanton, CA). This device consists of aninflow graft, a central pump with power supply, and anoutflow graft that contains a bend relief portion anchored tothe central pump by a snap/screw ring (Fig. 1B). Discon-nection or kinking of the bend relief mechanism is an un-common device-specific problem that can compromise theoutflow graft, causing unique problems. This case seriesdescribes 2 patients with complete LVAD bend relief systemdisconnection that presented with different clinical mani-festations and intraoperative challenges. On retrospectiveanalysis, this diagnosis can be made with a simple chestroentgenogram.

Case Presentations

Case 1

A 65-year-old man who had an HM II LVAD implanted5 weeks previously was readmitted to the hospital forbleeding, the cause of which was not yet determined. Upper

no source for the continued bleeding was seen. At 10 weeksafter LVAD implantation, there was progressive develop-ment of shortness of breath over 3 weeks, as well as sig-nificant LVAD parameter changes from normal flow tounmeasurable flow readings and increased speed and pul-satility indices; finally, an echocardiogram demonstrated aseverely dilated left ventricle, LVAD dysfunction wasinferred, and the patient’s heart transplant list status wasincreased accordingly. Consequently, the patient under-went heart transplantation and on explantation of theLVAD, it was seen that the bend relief mechanism thatnormally attaches the outflow graft to the LVAD had comeapart and was also impinging on and causing disruption ofthe outflow graft (Fig. 1C). After retrospective analysis, aroutine chest roentgenogram performed during hospitaladmission demonstrated an almost complete disconnectionbetween the outflow graft and the LVAD (Fig. 1, A and B[white arrows]).

Case 2

A 50-year-old man with dilated cardiomyopathy under-went an uneventful LVAD implantation; however, onpostoperative day 10, he experienced symptomatic episodesof ventricular tachycardia only when being positioned in asitting or upright state. These episodes of syncopal ventric-ular tachycardia were refractory to medical treatment,including antiarrhythmic agents and modulation of deviceparameters. Consequently, the patient’s transplant list statuswas increased. The patient received a heart, and duringtransplantation the LVAD was seen to have a bend reliefdisconnection. This device graft complication could have

d by Elsevier Inc. All rights reserved.

Figure 1. (A) Lateral chest roentgenogram of a patient with a leftventricular assist device ( LVAD) demonstrating band relief discon-nection between the LVAD central pump body and the outflow graft(white arrow). (B) HeartMate II (HM II) device with inflow cannula(blue) and other features of the device. (C) Pathology photograph ofthe explanted HM II device with bend relief shifted upward, screwcap, and a region of polyester (Dacron) outflow graft disruption (ar-row). ([B] reprinted with permission from Thoratec Corporation,Pleasanton, CA.)

247.e14 Canadian Journal of CardiologyVolume 30 2014

accounted for this patient’s cause of symptomatic ventriculartachycardia. A routine chest roentgenogram was able todemonstrate the complete disconnection of the HM II bandrelief mechanism (Fig. 2, A and B, arrows) when comparedwith a normal LVAD chest radiograph (Fig. 2, C and D,lines). Alternatively, the normal appearance of the apicalinflow connection between the left ventricular apex and theHM II demonstrates a loss of continuity, because thisportion of the device has a soft radiolucent polymer (Fig. 2,A, C, and D, arrowheads).

DiscussionBend relief disconnection as observed in these 2 cases is

rare but can have varied clinical presentations and maymimic other more commonly observed complications such

as device thrombosis and arrhythmia.2 Furthermore, thisadverse event can be identified by a routine chest roent-genogram rather than at the time of surgical explantation.Ultimately in 2012, Thoratec released a voluntary world-wide medical device recall on their HM II systems becauseof disconnection of the outflow graft bend relief. Theincidence of bleeding related to abrasion or cutting of thegraft was found to be 0.10% (3 cases out of 3200),3 whereasour institution’s incidence was higher at 6.5% (2 of 31).Although another centre previously reported on patientswith bleeding resulting from a partial or complete bendrelief disconnection in HM II devices,4 this case series isunique because it describes the only Canadian experience aswell as the fact that orthostatically mediated ventriculartachycardia in patients with LVADs may also occur fromthis complication. A possible mechanism for these episodesof ventricular tachycardia may have been a transient in-crease in outflow graft kinking with the patient leaningforward (back flexion), causing brief obstruction in the HMII and resultant left ventricular dilatation. Although newHM II models have a redesigned bend relief mechanism,older affected models can be reinforced by either placing aThoratec-developed clip or performing the “Champaignwire correction” with a sternal wire.4

In summary, disconnection of the bend relief can occurearly or late after HM II device implantation. It can havevarying clinical presentations and may be easily diagnosed onroutine chest roentgenography. Clinicians managing thesepatients should have a high index of suspicion for this prob-lem and consider screening patients with quarterly chestroentgenograms focusing on evidence of kinking of the bendrelief outflow graft connection.

DisclosuresThe authors have no conflicts of interest to disclose.

References

1. Holman WL, Naftel DC, Eckert CE, et al. Durability of left ventricularassist devices: Interagency Registry for Mechanically Assisted CirculatorySupport (INTERMACS) 2006-2011. J Thorac Cardiovasc Surg2013;146:437-41.

2. Slaughter MS, Pagani FD, Rogers JG, et al. Clinical management ofcontinuous-flow left ventricular assist devices in advanced heart failure.J Heart Lung Transplant 2010;29(4 suppl):S1-39.

3. US Food and Drug Administration. Thoratec Corporation, HeartMate II leftventricular assist system (LVAS): class 1 recalldoutflow graft may kink ordeform (March, 2012). Available at: http://www.fda.gov/safety/medwatch/safetyinformation/safetyalertsforhumanmedicalproducts/ucm298710.htm.Accessed May 1, 2013.

4. Yuzefpolskaya M, Uriel N, Chow DS, et al. Prevalence and timing ofbend relief disconnection in patients supported by the late versionHeartMate II left ventricular assist device. J Heart Lung Transplant2013;32:320-5.

Figure 2. (A) Posteroanterior and (B) lateral chest roentgenograms in a patient with a left ventricular assist device (LVAD), demonstrating bendrelief disconnection (white arrows). (C) Normal posteroanterior and (D) lateral chest roentgenograms demonstrate an inline, nonkinked bend reliefmechanism (parallel to blue and white lines). Arrowheads indicate the normal appearance of the apical inflow connection between the left ven-tricular cavity and the LVAD.

Toeg et al. 247.e15LVAD Outflow Graft Disconnection