Aissaoui, Nadia

Börgermann, Jochen

Gummert, Jan

Morshuis, Michiel

Elsevier - Publisher Connector 

HeartWare continuous-flow ventricular assist device thrombosis: The Bad Oeynhausen experience 

Case Reportsreaction within the vein that results in adhesion formation.
The proximity of great vessels allows scarring between ad-
jacent artery and vein. Laser extraction in thin-walled veins
may involve removal or tearing of the venous wall, thus cre-
ating a communication with the adjacent artery.CONCLUSIONS
Laser-assisted lead extraction has significantly improved
the success and efficiency of lead removal. Arteriovenous
fistula formation is a rare but potentially catastrophic com-
plication. Success with endovascular techniques has pro-
vided an effective and less invasive management option.
These cases stress the importance of judicious application
of extraction guidelines, meticulous technique, and promptFrom the Heart & Diabetes Center North Rhine-Westphalia, Bad Oeynhausen,
Germany.
Disclosures: Authors have nothing to disclose with regard to commercial support.
HeartWare is manufactured by HeartWare International, Inc, Framingham, Mass.
Received for publication Dec 5, 2011; accepted for publication Dec 14, 2011;
available ahead of print Jan 16, 2012.
Address for reprints: Nadia Aissaoui, MD, Department of Thoracic and Cardiovascu-
lar Surgery, Heart & Diabetes Center North Rhine-Westphalia, Georgstrasse 11,
32545 Bad Oeynhausen, Germany (E-mail: nadia.aissaoui@sat.aphp.fr).
J Thorac Cardiovasc Surg 2012;143:e37-9
0022-5223/$36.00
Copyright  2012 by The American Association for Thoracic Surgery
doi:10.1016/j.jtcvs.2011.12.035
The Journal of Thoracic and Cadiagnosis and management of these potentially catastrophic
complications.References
1. Bracke FA, van Gelder B, Meijer A. Arteriovenous fistula after injury of the left
Internal mammary artery during extraction of pacemaker leads with a laser sheath.
Pacing Clin Electrophysiol. 1999;2:833-4.
2. Kumins NH, Tober JC, Love CJ, Culbertson TA, Gerhardt MA, Irwin RJ, et al. Ar-
teriovenous fistulae complicating cardiac pacemaker lead extraction: recognition,
evaluation, and management. J Vasc Surg. 2000;32:1225-8.
3. Milla F, Mack CA, Girardi LN. Arteriovenous fistula after laser-assisted pace-
maker lead extraction. Ann Thorac Surg. 2006;81:2304-6.
4. Lawton JS, Moon MR, Curci JA, Rubin BG, Smith TW, Gleva MJ, et al. Manage-
ment of arterial injuries caused by laser extraction of indwelling venous pace-
maker and defibrillator leads. Pacing Clin Electrophysiol. 2006;29:917-20.
5. O’Connor DJ, Gross J, King B, SuggsWD, Gargiulo NJ 3rd, Lipsitz EC. Endovas-
cular management of multiple arteriovenous fistulae following failed laser-
assisted pacemaker lead extraction. J Vasc Surg. 2010;51:1517-20.HeartWare continuous-flow ventricular assist device thrombosis: The
Bad Oeynhausen experienceNadia Aissaoui, MD, Jochen B€orgermann, MD, PhD, Jan Gummert, MD, PhD, and Michiel Morshuis, MD,
Bad Oeynhausen, GermanyThe HeartWare (HeartWare International, Inc, Framing-
ham, Mass), ventricular assist device (VAD) is a small,
third-generation, implantable continuous-flow VAD.1 De-
spite this system’s advantages, the rates of thrombus forma-
tion and thromboembolic events are not negligible and can
reach 8%.1
Pump thrombus requires emergency treatment to restore
an adequate flow and to avoid life-threatening complica-
tions. The therapeutic options are few: thrombolytic ther-
apy, either systemic or local,2,3 with the accompanying
risks of recurrence and bleeding, and surgical device
exchange, which is associated with the problems typical
of an urgent reoperative procedure.4
There are currently no specific recommendations con-
cerning the management of pump thrombosis. This reportaims to summarize the Bad Oeynhausen experience with
the management of HeartWare VAD thrombus.CLINICAL SUMMARY
Patients
Between August 2009 and May 2011, 98 patients re-
ceived HeartWare VADs (88 left VADs and 10 biventricular
VADs) in Bad Oeynhausen, Germany. Six patients showed
development of clinical signs of pump thrombosis associ-
ated with device malfunction. One patient had pump throm-
bosis develop on 2 separate occasions (within 6 months of
each other) as a result of noncompliance with the anticoagu-
lation regimen.Diagnosis of Device Thrombosis
The diagnosis of thrombosis was most often made by in-
direct evidence. Clinical suspicion was raised in the cases of
patients 1, 2, 3, and 4 because of documented subtherapeu-
tic international normalized ratio values (patient 3), history
of a transitory ischemic attack (patient 1), or icterus and
dark urine on examination (patients 1, 2, 3, and 4). Pump
checks revealed in all patients an increase of power con-
sumption plus abnormally increased flow values differing
from baseline. Laboratory tests always showed high
lactate dehydrogenase and free hemoglobin levels. Demo-
graphic data are summarized in Table 1.rdiovascular Surgery c Volume 143, Number 4 e37
TABLE 1. Patient characteristics and treatment
Case Age (y) VAD Sex Treatment at event Power demand (W) Flow rate (L/min) INR PTT (s) Free Hb (mg/dL) LDH (IU/L)
1 57 LVAD M Heparin 6.5 10 1 50 71 1040
2 50 LVAD F Phenprocoumon plus ASA 7.6 7.8 4.1 45 561 5160
3 50 LVAD M Phenprocoumon plus ASA 19.3 10 2.7 32 203 2340
4* 48 LVAD F None 13.9 10 1.2 24 404 3660
48 LVAD F Phenprocoumon plus ASA 9.1 10 1.6 32 854 9600
5 36 RVAD M Heparin 8.9 10 1.9 68 141 2390
6 59 RVAD M Heparin 6.9 6.0 1.3 48 69 683
VAD,Ventricular assist device; INR, international normalized ratio; PTT, partial thromboplastin time;Hb, hemoglobin; LDH, lactate dehydrogenase; LVAD, left ventricular assist
device; ASA, aspirin [INN acetylsalicylic acid]; RVAD, right ventricular assist device. *Patient 4 had pump thrombosis develop on 2 occasions (within 6 months) as a result of
noncompliance with the anticoagulation regimen. These occasions are listed in chronologic order.
Case ReportsThe echocardiography was helpful because it showed in-
direct signs of pump malfunction in all patients with left
VADs, such as left ventricular dilatation and intermittent
opening of the aortic valve, but a left ventricular thrombus
was identified in 1 patient (patient 1).
It was not possible to perform computed tomographic ex-
aminations, because the clinical status was often unstable.
The diagnosis was always confirmed by the examination
of the explanted devices showing thrombotic material in-
side the HeartWare VAD or the inflow cannula (Figure 1).Management
Pump exchange. The pump exchange procedure was per-
formed off pump or with cardiopulmonary bypass support
through a median sternotomy.4 A small dose of heparin
(only half of the usual dose) was used in case of off-pump
surgery to avoid stasis during the exchange. In our center,
off-pump surgery was preferred when the hemodynamic
status of the patient was unstable.
Thrombolytic therapy. Tenecteplase was used in our 2
cases of thrombolytic therapy. Thrombolytic treatment
was standardized and administered on the basis of body
weight, with a maximum dose of 10,000 units (50 mg) as
a single intravenous bolus given in 5 to 10 seconds.5FIGURE 1. Right ventricular assist device after explantation. Fibrin and
the clot can be seen inside the pump.
e38 The Journal of Thoracic and Cardiovascular SurgBecause partial thromboplastin time frequently increases
during lysis with recombinant tissue plasminogen activator,
the heparin dose was lowered. Intravenous infusion of hep-
arin was titrated to maintain an activated partial prothrom-
bin time of 50 to 60 seconds, and coagulation parameters
were monitored every 4 hours. After lysis, antiplatelet ther-
apy was continued.Outcomes
Pump exchange was successfully performed in 5 patients
(patients 1, 2, 4, 5, and 6), in 3 cases with the off-pump tech-
nique (patients 1, 5, and 6). No severe bleeding or tampo-
nade occurred in the patients treated by surgery.
Patient 3 was initially treated with thrombolytic therapy,
but this failed on day 4. Surgery was needed because there
was severe bleeding at the driveline and administration of
an additional dose of thrombolytic agent was not feasible.
Because of poor compliance and discontinuation of anti-
coagulation therapy, patient 4 had a second episode of pump
thrombosis 6 months after the first. He was treated with
thrombolytic therapy, which was successful and free of
complications.
All patients were discharged from the intensive care unit.
Patient 6 died of sepsis 1 month after pump exchange.DISCUSSION
Pump exchange, unlike thrombolytic therapy, was always
successful in our series. Thrombolytic therapy potentially
induces fast thrombolysis. Tenecteplase is a third-
generation thrombolytic agent with a longer plasma
half-life, better fibrin specificity, and higher resistance to in-
hibition by plasminogen activator than previous thrombo-
lytic agents.5 In our study, thrombolytic therapy was
unsuccessful in 1 of 2 patients. In the largest literature study,
by Rothenburger and colleagues,2 thrombus recurred after
thrombolysis 3 times in 8 patients. In fact, thrombolytic ther-
apy cannot completely eradicate the thrombus, which may
immediately or quickly rebuild after thrombolysis. Further-
more, systemic thrombolysis leads to a secondary hyperco-
agulable state, which may persist for 3 days.5 Finally,ery c April 2012
Case Reportsthrombolysis has adverse effects, including hemorrhage,
such as occurred in patient 3 in whom thrombolysis failed.
Some authors have reported cases of successful local
thrombolysis in cases of pump thrombosis.3 Such beneficial
effects might be explained by high local concentrations of
the thrombolytic agent.We do not think that local thrombol-
ysis will improve the results of thrombolysis, because it still
has systemic effects and is associated with bleeding compli-
cations. Moreover, the use of catheters may be dangerous in
the vicinity of the continuous inflow cannula, and the exam-
ination requires the use of contrast agent and irradiation.
Pump exchange permits complete replacement of the de-
vice. No thrombus remains. Pump replacement does have
the shortcomings of all reoperative procedures,4 exposing
patients on antithrombotic therapy to the risk of major
bleeding complications, right ventricular failure and infec-
tion. Off-pump implantation of the VAD, however, greatly
shortens the duration of the procedure and may avoid the
adverse effects of cardiopulmonary bypass, such as need
for transfusions and systemic inflammation.4 We performed
off-pump surgery in 3 cases. Despite difficulty sometimes in
seeing inside the ventricle in the absence of cardiopulmo-
nary bypass, we could always in our patients evacuate theThe Journal of Thoracic and Cathrombotic material in the ventricle. Successful use of off-
pump surgery for implanting VADs has been reported in
the literature4 but requires further confirmation.
Pump exchange is an effective treatment for HeartWare
VAD thrombosis. The associated risk is acceptable. Off-
pump surgery may reduce the risks observed with reopera-
tive surgery.
We thank Daniela Roefe, VAD coordinator, and Ellen von
Roessing for their contributions.
References
1. Strueber M, O’Driscoll G, Jansz P, Khaghani A, LevyWC,Wieselthaler GM, et al.
Multicenter evaluation of an intrapericardial left ventricular assist system. J Am
Coll Cardiol. 2011;57:1375-82.
2. Rothenburger M, Wilhelm MJ, Hammel D, Schmidt C, Tjan TD, B€ocker D, et al.
Treatment of thrombus formation associated with the MicroMed DeBakey VAD
using recombinant tissue plasminogen activator. Circulation. 2002;106(12 Suppl.
1):189-92.
3. Kiernan MS, Pham DT, Denofrio D, Kapur NK. Management of HeartWare left
ventricular assist device thrombosis using intracavitary thrombolytics. J Thorac
Cardiovasc Surg. 2011;142:712-4.
4. Gregoric ID,LaFrancescaS,MyersT,CohnW,LoyalkaP,KarB, et al.A less invasive
approach to axial flow pump insertion. J Heart Lung Transplant. 2008;27:423-6.
5. Dunn CJ, Goa KL. Tenecteplase: a review of its pharmacology and therapeutic ef-
ficacy in patients with acute myocardial infarction. Am J Cardiovasc Drugs. 2001;
1:51-66.rdiovascular Surgery c Volume 143, Number 4 e39


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HeartWare continuous-flow ventricular assist device thrombosis: The Bad Oeynhausen experience

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