Successful IntraventricularThrombolysis During VentricularAssist Device SupportClaudio Russo, MD, Anna Maria De Biase, MD,Giuseppe Bruschi, MD, Salvatore Agati, MD, andEttore Vitali, MD

Departments of Cardiology and Cardiovascular Surgery,Niguarda Hospital, Milan, Italy

Different types of mechanical ventricular assist devicesare available for treating end stage congestive heartfailure. Despite technical improvements, however, vari-ous complications are still reported for patients duringmechanical support. We report our experience with in-traventricular thrombolysis as a treatment for possiblethrombosis of a continuous flow device that had beenimplanted as a bridge to heart transplantation. Thisapproach has been demonstrated to be both effective andsafe.

(Ann Thorac Surg 2002;73:1628–9)© 2002 by The Society of Thoracic Surgeons

The ventricular assist device (VAD) is a realistic optionas a bridge to heart transplantation for patients with

end-stage congestive heart failure. We describe our suc-cessful experience with a case of likely acute thrombosisof a DeBakey VAD that was treated with left ventricle(LV) thrombolysis.

The DeBakey VAD (MicroMed Technology, Inc, Hous-ton, TX) [1] is an electromagnetically actuated, implant-able titanium axial flow blood pump designed for LVsupport. The pump connects the apex of LV to theascending aorta and is smaller compared with otherkinds of VADs. An ultrasonic Doppler flow probe isplaced around the outflow conduit (Fig 1). The device isconnected by a percutaneous cable to an external con-troller. The pump does not have valves and can produceup to 10 L/min continuous flows, with a rotor speed of7,500 to 12,500 rpm. The rotor speed can be adjustedthrough the external unit. The wearable external control-ler continuously displays pump operating indicators:speed, flow, power, and battery charge. Power is suppliedby a central unit, or during patient mobilization, by two12-V rechargeable batteries.

A 54-year-old woman was admitted to the hospital incardiogenic shock secondary to acute myocardial infarc-tion. She underwent successful urgent percutaneoustransluminal angioplasty. Despite optimal medical ther-apy, progressive cardiac insufficiency developed. After 3months, the patient was readmitted to the hospital be-cause of severe heart failure and she was placed on theurgent list for heart transplantation. No hemodynamicimprovement occurred even with maximal intravenous

inotropic therapy (dopamine 10 �g � kg�1 � min�1 anddobutamine 10 �g � kg�1 � min�1): cardiac index was lessthan 2 L � min�1 � m�2, systolic blood pressure was lessthan 90 mm Hg, and left atrial pressure was more than20 mm Hg. LV ejection fraction was less than 20%;neither mitral insufficiency nor endoventricular throm-bus was present. The right ventricle had a mild hypoki-nesia. Because of clinical deterioration and initial renaland hepatic dysfunction, we decided to implant a VAD asa bridge to heart transplantation.

After approval by the ethics committee and the pa-tient’s informed consent, she was enrolled in the De-Bakey VAD European multicenter, nonrandomizedstudy. We decided to implant a DeBakey VAD because ofthe small body surface area (1.4 m2) of the patient. Thedevice was implanted with extracorporeal circulation andcardioplegic arrest. Extracorporeal circulation was dis-continued when the VAD index was more than 2.5 L �min�1 � m�2. The implantation procedure was unevent-ful. A Gore-Tex sheet (W. L. Gore & Associates, Flagstaff,AZ) was wrapped around the device to prevent adhe-sions [2]. At the end of the operation the patient wasstable and the mechanical support was working properly;mixed venous O2 saturation was more than 70% andcardiac index was more than 2.5 L � min�1 � m�2. Theposition of the inflow cannula in the LV and the rightventricle function were assessed by transesophagealechocardiography.

The early postoperative period was uneventful: meanblood pressure was always more than 90 mm Hg andend-organ dysfunction recovered. After a first phase ofintravenous heparin, a combined anticoagulation proto-col was used: dipyridamole, penthoxyfilline, aspirin, war-farin sodium, and low molecular weight heparin [3]. Theinternational normalized ratio and partial thromboplas-tin time were controlled daily and once a week a throm-boelastogram was studied. Ten days after implant, thepatient was discharged from the intensive care unitwithout inotropic medical support; she was confident

Accepted for publication Oct 10, 2001.

Address reprint requests to Dr Russo, Department of Cardiac Surgery “A.De Gasperis,” Niguarda Hospital, Piazza Ospedale Maggiore, 3, 20162Milan, Italy; e-mail: cf.russo@tiscalinet.it.

Fig 1. The DeBakey ventricular assist device human configuration:(A) the titanium axial flow pump connects (B) the apex of the leftventricle to (C) the ascending aorta. The outflow graft to the ascend-ing aorta goes through (D) an intrathoracic Doppler flow probe.

1628 CASE REPORT RUSSO ET AL Ann Thorac SurgTHROMBOLYSIS DURING MECHANICAL VENTRICULAR SUPPORT 2002;73:1628–9

© 2002 by The Society of Thoracic Surgeons 0003-4975/02/$22.00Published by Elsevier Science Inc PII S0003-4975(01)03437-3

with the device and she attended a rehabilitation pro-gram. Laboratory tests and echocardiography were per-formed regularly. No hemolysis occurred.

On the 112th postoperative day, the patient experi-enced increasing dyspnea. The pump controller indi-cated an abnormal increase in current from 0.6 A to 1.4 Aand in power from 7.8 W to 15 W—changes suggestive ofincreasing friction on the pump impeller, possibly due toVAD thrombosis. Despite the patient’s adequate antico-agulation profile (international normalized ratio 3.3, par-tial thromboplastin time 60 seconds), we immediatelystarted intravenous heparin administration. Transtho-racic echocardiography did not demonstrate endoven-tricular thrombus, and no stenosis was observed at theanastomosis of the outflow graft. Contrast computedtomography scan did not show obstruction or kinking ofthe outflow graft. The patient’s condition continued todeteriorate; the pump controller’s current and powerindicators remained higher than normal and flow ratedecreased to 2.1 L/min. The VAD stopped twice but thepump restarted both times, owing to its automatic restartprogram.

We suspected a pump thrombosis. According to themanufacturer’s technical support staff advice, we decidedto perform endoventricular thrombolysis delivering re-combinant tissue plasminogen activator into the LV. Weconsidered low-dose local administration safer than sys-temic thrombolysis. Angiography was not performedbecause we were concerned that radiopaque contrastcould further increase blood viscosity, worsening pumpfriction. Three hours later a 5F pigtail catheter wasinserted through the right femoral artery into the LV,close to the inflow cannula. The aortic valve was easilycrossed by the catheter, which remained stable in the LVdespite the continuous negative pressure caused by theVAD. Three recombinant tissue plasminogen activatorboluses (12, 10, and 10 mg) were administered into the LVover 15 minutes; after the last dose, a 50-mg sodiumheparin bolus was administered. After 20 minutes, pumppower and current values decreased, flow rate increased,and the patient’s clinical status improved. After 3 hoursthe pump indicators were normal, the flow was 4.5 L/min,and there was complete hemodynamic recovery.

No neurologic events occurred; only transient hematu-ria occurred. The pump continued to work properly. Wecontrolled more strictly the coagulation profile but wedid not change our protocol. On the 142nd day after VADimplant, the patient underwent heart transplantation andwas discharged. At VAD explantation, no clot was foundin the LV, in the vascular graft, or at the aortic anasto-mosis. We could not assess the inner part of the pumpbut, considering the effectiveness of thrombolysis, itmade sense that if a clot had been in the device, it wouldnot be possible to find it anymore.

Comment

Thrombosis and thromboembolism have been reportedin patients on mechanical support despite correct antico-agulation management [4, 5]. Testing of the DeBakeyVAD has not identified any areas of blood stasis orturbulence that would promote thrombosis. But accord-

ing to the manufacturer, this complication was previouslyreported in patients with a DeBakey VAD; in some casesthe device was urgently replaced [6].

In our experience, the device dysfunction was appar-ently caused by a VAD thrombus and, indeed, immediateintraventricular thrombolysis fixed the pump failure.This case represents the only adverse event in our seriesof 9 DeBakey VAD implants. The immediate administra-tion of low-dose LV thrombolysis was safe and effective.This approach is justified to avoid the risk of high-dosesystemic thrombolysis or device replacement.

References

1. DeBakey M. A miniature implantable axial flow ventricularassist device. Ann Thorac Surg 1999;68:637–40.

2. Vitali E, Russo C, Colombo T, Lanfranconi M, Bruschi G.Modified pericardial closure technique in patients with ven-tricular assist device. Ann Thorac Surg 2000;69:1278–9.

3. Colombo T, Milazzo F, Agati S, et al. LWMH and throm-boelastography (TEG) for management of anticoagulation inlong term circulatory support. Mechanical Circulatory Sup-port—Today’s Facts and Future Trends. Bad Oeynhausen,Germany, October 12–14, 2000.

4. Stevenson LW, Kormos RL, Bourge RC, et al. Mechanicalcardiac support 2000. Current applications and future trialdesign. J Am Coll Cardiol 2001;37:340–70.

5. El-Banayosy A, Arusoglu L, Kizner L. Novaco left ventricularassist system versus Heartmate vented electric left ventricularassist system as a long-term mechanical circulatory supportdevice in bridging patients: a prospective study. J ThoracCardiovasc Surg 2000;119:581–7.

6. Noon GP, Morley DL, Irwin S, et al. Clinical experience withthe MicroMed DeBakey ventricular assist device. Ann ThoracSurg 2001;71:S133–8.

Retropericardial HematomaComplicating Off-Pump CoronaryArtery Bypass SurgeryToshihiro Fukui, MD, Shigefumi Suehiro, MD,Toshihiko Shibata, MD, Koji Hattori, MD, andHidekazu Hirai, MD

Department of Cardiovascular Surgery, Osaka City UniversityMedical School, Osaka, Japan

We report the case of a retropericardial hematoma aftertriple-vessel off-pump coronary artery bypass grafting.Transesophageal echocardiography demonstrated a ret-ropericardial hematoma that compressed the left atriumanteriorly and suppressed cardiac function. Injury to thepulmonary vein during placement of deep pericardialsutures and postoperative infusion of heparin were thelikely causes of this rare but potentially fatal complica-tion of an off-pump bypass operation.

(Ann Thorac Surg 2002;73:1629–31)© 2002 by The Society of Thoracic Surgeons

Accepted for publication Oct 16, 2001.

Address reprint requests to Dr Fukui, Department of CardiovascularSurgery, Osaka City University Medical School, 1-4-3 Asahi-machi,Abeno-ku, Osaka 545-8585, Japan; e-mail: tm-fukui@gem.hi-ho.ne.jp.

1629Ann Thorac Surg CASE REPORT FUKUI ET AL2002;73:1629–31 RETROPERICARDIAL HEMATOMA AFTER CABG

© 2002 by The Society of Thoracic Surgeons 0003-4975/02/$22.00Published by Elsevier Science Inc PII S0003-4975(01)03461-0