Long-Term Paracorporeal Ventricular Support Systems: A Single-Center Experience M. Ozbaran, T. Yagdi, C. Engin, S. Erkul, O. Balcioglu, B. Baysal, S. Nalbantgil, and S. Ertugay ABSTRACT Background. The Berlin Heart EXCOR is a first-generation paracorporeal, pneumatic ventricular assist device that creates pulsatile flow. It can be used for long-term support of the left and/or right ventricule during end-stage heart failure. The aim of this study was to share our clinical experience in 54 patients. Methods. Between April 2007 and August 2012, 54 patients with end-stage heart failure underwent Berlin Heart EXCOR ventricular assist device implantation, including 5 females and 9 children. Twenty-four patients (44%) were in Intermacs level 1, 11 (21%) in level 2, and 19 (35%) in level 3. Biventricular support was applied to 13 patients. Device implantation was performed with an “on pump” beating heart technique while 6 other patients underwent intervention operations while the aortic valve has under cross-clamp. Tricuspid annuloplasty was performed in 6 patients. Results. There was no peroperative death. Nine patients (17%) underwent re-exploration because of hemorrhage in the early postoperative period. Heart transplantation was performed in 32 patients (59%), while 10 (19%) are still under pump support with a mean follow-up of 13 months. Although 1 was successfully weaned from the system, 11 patients (20%) died during the support. Pump-head exchange was required 19 times in 17 patients because of visible thrombus or fibrin deposit in the pump head or due to membrane rupture. Discussion. The use of long-term paracorporeal assist devices has decreased in recent years because of the increased popularity of implantable devices that permit longer survival and a better quality of life. We believe that the Berlin Heart EXCOR has a special role because it can be used in pediatric patients and especially in critical conditions like Intermacs levels 1 and 2. ND-STAGE heart failure is one of the important causes for morbidity and mortality. A number of illnesses cause this desperate situation including coronary artery disease and its complications, idiopathic dilated cardiomyopathy, and congenital heart defects. Heart transplantation is still the gold standard treatment for patients with end-stage heart failure.1 As a result of donor scarcity, mechanical circulatory support (MCS) using ventricular assist devices (VAD) has developed as an innovative rescuer for patients with end-stage heart failure.2 Mechanical circulatory support substantially improves vital functions. Compared with conventional therapy MCS seeks to keep the patient alive until transplantation, and to provide greater exercise tolerance, superior quality of life and recovery of organ malfunction.3 Today, more than 35% of
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patients a waiting transplantation are undergoing.1 VAD can be also used for recovery, or destination therapy in carefully chosen patients who require left ventricular, right ventricular, or biventriculars support.2 The Berlin Heart EXCOR (Berlin Heart AG, Berlin, Germany) is a first-generation device that contains a paracorporeal, pneumatic compressor-drived diaphragm pump with a tilting disk or polyurethane flexible trileaflet valves, silicone cannulas, and a stationary driving unit. The pump From the Departments of Cardiovascular Surgery and Cardiology, Ege University Medical Faculty, Izmir, Turkey. Address reprint requests to Tahir Yagdi, Department of Cardiovascular Surgery, Ege University Medical Faculty, 35100, Izmir, Turkey. E-mail:
[email protected]
© 2013 by Elsevier Inc. All rights reserved. 360 Park Avenue South, New York, NY 10010-1710
0041-1345/–see front matter http://dx.doi.org/10.1016/j.transproceed.2013.02.073
Transplantation Proceedings, 45, 1013–1016 (2013)
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head holds a polyurethane blood pump with a multilayer flexible membrane that separates the blood and air chambers. The system has adult pumps available in 50, 60, and 80 mL sizes; pediatric pump sizes are 10, 25, and 30 mL. This device provides left, right, or biventricular support for adult and pediatric patients.4 The worldwide popularity of EXCOR in pediatric patients has increased dramatically in the last decade.5 Herein we have presented implantations in 54 patients of the Berlin Heart EXCOR VAD in our department. METHODS Between April 2007 and October 2012, 54 patients (48 males and 6 females) with acute or chronic end-stage heart failure underwent Berlin Heart EXCOR VAD implantation, including 9 children younger than 16 years of age. The patients’ ages spanned 1.5 to 63 years (mean, 38 ⫾ 18), mean height 165 ⫾ 22 cm (range, 77–189), weight 69 ⫾ 22 kg (range, 8 –107 kg), and body surface area 1.74 ⫾ 0.41 m2 (range, 0.45–2.2 m2). The etiologies of heart failure among patients undergoing EXCOR implantation were dilated cardiomyopathy (n ⫽ 45; 83%) and ischemic cardiomyopathy (n ⫽ 9; 17%). Before VAD implantation, 24 patients (44%) were Intermacs level 1, 11 (21%) were level 2, and 19 (35%) were level 3.
Operative Technique After performing a midline sternotomy incision and delivering systemic heparinization, arterial cannulation was achieved via the ascending aorta or femoral artery. Venous cannulation was performed using a bicaval right atrial technique. After initiation of cardiopulmonary bypass, the patient was placed in the head down position. A circular hole was created at the left ventricular apex with suitable numbers of polypropylene 3/0 or 4/0 sutures supported with Teflon pledgets placed around the hole. An apical cannula was introduced with close-fitting polypropylene sutures already placed around the hole. An additional circular continuous purse-string suture was placed around the apical cannula to prevent bleeding. The apical cannula was passed through the abdominal wall. The heart was defibrillated if necessary. During this period deairing was performed carefully. A side clamp was inserted into the ascending aorta. After making a longitudinal aortotomy incision, the aortic outflow cannula was placed in the ascending aorta with 4/0 or 5/0 continuous or mattress polypropylene sutures supported with Teflon pledgets. The outflow cannula was tunneled to exit the abdominal skin. When the biventricular support mode was needed, a right atrial inflow cannula was placed into the right atrial wall with 4/0 or 5/0 continuous or mattress polypropylene sutures reinforced with Teflon pledgets. The right-sided outflow cannula was anastomosed to the main pulmonary artery using the same technique as the aortic anastomosis. After deairing, the left-sided pump was connected to the left ventricular apical and aortic outflow cannulae. The same procedure was accomplished for the right-sided pump and right-sided cannulas. Visible air bubbles were aspirated with a deairing needle. The pump was connected to the driving unit and the assisted circulation initiated; cardiopulmonary bypass flow was decreased gradually to be finally stopped. An additional valvular procedure was performed under x-clamp in 12 patients (22%). In 3 subjects with significant aortic regurgitation, primary coaptation stitches at the 3 leaflet centers were
OZBARAN, YAGDI, ENGIN ET AL applied to approximate the fibrous nodules of Arantius. The mechanical aortic valve was replaced with a stentless bioprosthesis in 3 patients; in 6, a tricuspid valve repair was performed using an annuloplasty ring. During postoperative follow-up, judicious right ventricular support and anticoagulation regimen were established, particularly for patients with poor right ventricular systolic functions employing inhaled nitric oxide (NO), milrinon, and catecholamines in the early postoperative period. We started fluid restriction and inhaled iloprost treatment in these patients after extubation. After 12–24 hours postoperative anticoagulation with unfractioned heparin infusions kept the activated partial thromboplastin time (aPTT) between 60 and 80 seconds as tested every 4 – 6 hours. Target aPTT levels were determined by the platelet count, fibrinogen level, and thromboelastography results. In addition to heparin, diyridamol was begun on postoperative day 3. Subsequently warfarin Na was given as an anticoagulant to keep the international normalized ratio (INR) at 2.7–3.5. Acetylsalicylic acid was started around day 5 to 6 after the operation after removal of the mediastinal drains. In some patients clopidogrel added as an antiaggregant according to the results of platelet aggregation tests. The transparent polyurethane pump chamber was regularly checked using light to detect possible thrombus and fibrin depositions.
RESULTS
Among 54 patients supported with the VAD, 13 received biventricular support. In all patients the Berlin Heart EXCOR was used for MCS. There was no peroperative death. The mean length of intensive care unit stay was 12 ⫾ 9 days (range, 5– 42). The mean support was 256 ⫾ 200 days (range, 3–704). The mean support time in pediatric cases was 384 ⫾ 207 days (range, 30 – 670). Ten (19%) patients are still on circulatory support. Thirty-two (59%) patients underwent heart transplantation. One subject who was managed with left VAD implantation and coronary artery bypass grafting was weaned from the system. The overall survival rate until transplantation or after weaning was 80% (n ⫽ 43). Nine patients (17%) underwent re-exploration because of postoperative hemorrhage or cardiac tamponade in the early postoperative period. Ten cerebrovascular complications occurred in 9 patients (17%), including 2 pediatric cases. Thromboembolic cerebral complications, including transient ischemic events and prolonged reversible ischemic neurological deficits, were observed in 4 patients, 1 of whom experienced a severe stroke and concomitant intracranial bleeding on postoperative day 420. Another subject displayed intracerebral hemorrhage, whereas 2 patients had nonfatal cerebral hemorrhages without neurological sequelal. Two pediatric patient died due to thromboembolic cerebrovascular complications after more than 400 days of support. Thrombus formations that caused pump dysfunction were encountered 17 times in 15 cases (28%), requiring pump head exchange. The mean support time to pump head exchange was 223.6 days (range, 30 – 414). Pump exchange was easily performed as soon as possible without anesthesia or adverse event. Cannula infection observed in 5 patients was controlled with local antiseptic dressings.
PARACORPOREAL VENTRICULAR SUPPORT SYSTEMS
Eleven patients (20%) died during mechanical circulatory support: 5 during the early postoperative period because of multi-organ failure or sepsis; 2 from hemorrhagic neurological complications; 1 from respiratory failure, and 1 from a skin malignancy with multiple-organ metastases during the late follow-up period. Two pediatric patients who could not find suitable donors for more than 450 days of support died from cerebrovascular events. DISCUSSION
Heart transplantation remains the gold standard treatment for end-stage cardiac failure. Many patients on the waiting list die due to the scarcity of donors. Mortality for small children during the waiting period is greater than that of adults, due to the relative inadequacy of pediatric donors. The 2-patients who died during the waiting period for transplantation among our pediatric group were younger than 3 years of age and we could not find a suitable donor for more than 450 days. The decision to establish mechanical support is critically important in patients with severe heart failure who may decompensate rapidly. Mechanical support can be a life-saving intervention for waiting list patients with worsening clinical status who otherwise would die before transplantation. Bridging to transplantation with MCS is sometimes the only option for patients with endstage heart failure who fail to respond adequately to inotropic support. Extending the waiting time to find a suitable donor and the possibility to restore vital organ functions are significant benefits of VADs. Various devices—paracorporeal pulsatile flow pumps, implantable continuous flow pumps, or total artificial heart– can be used for long-term support of adult patients. In small children there are limited options as a bridge to transplantation. The Berlin Heart EXCOR Pediatric pump is available in a large number of sizes.6 It can be implanted easily even in newborns and small-sized pediatric patients. Preoperative optimization has reduced mortality and morbidity during VAD support. Discharge from the hospital become feasible upon return of organ functions. The cost of hospitalization and the risk of hospital infections are lessened and the functional and psychological state of the patients are improved. Left ventricular end-diastolic pressure normally decreases after starting LVAD. Especially upon early postoperative follow-up, right ventricular support is one of the main issues. Appropriate support in the early postoperative period with inhaled NO, milrinon, and catecholamines eliminates the need for VAD for the right ventricle. The need for biventricular support is one of the main factor associated with early mortality and morbidity after VAD implantation.7 In our series, right-sided heart failure, sepsis, and multi-organ disease were the predominant complications among patients who died in the early postoperative period. The perioperative management to prevent surgical bleeding is essential especially for patients with preoperative hepatic dysfunction with defective coagulation profiles.8
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The bleeding tendency may be augmented as a result of the combined use of anticoagulation and antiplatelet therapy requiring careful anastomotic and hemostatic techniques. Our modification of the apical anastomosis places requiring an additional circular purse string suture around the inflow cannula. We believe that it alleviates the stress on the separate pledget sutures around the inflow cannula placed during fixation to the ventricular apex, decreasing the risk of bleeding. We also employ a variation to perform the aortic anastomosis: First, we place a sufficient number of 4/0 or 5/0 pledgeted polypropylene sutures between the aorta and rigid outflow cannula during aortic side-clamping, and second, we release the side-clamp and tie all sutures under a stress-free condition. We believe that by this method we prevent unwanted stress and tearing of the aorta while tying the rigid cannula to the delicate aorta. Our results showed that concomitant valvular surgery during EXCOR implantation is a good option that can be performed safely for patients with valvular problems. Thrombus formation is one of the major complications causing pump failure. Fortunately, in our series the severity and frequency of thromboembolic complications were reasonable. Tendencies toward an increased frequency of preoperative and postoperative cardiac arrhythmias as well as preoperative internal cardiac defibrillator requirements were observed among our study population. Regular examination of the pump chambers is important to detect small fibrin deposits before they become large enough to threaten the patient. Bigger thrombi harassed exchange of the pump, while is usually fast, easy, and safe. Close monitoring is required to achieve adequate anticoagulation, keeping the INR levels at acceptable levels. Thromboembolic or hemorrhagic cerebral problems occurred among 17% of our patients. Balanced management of anticoagulation can decrease the incidence of cerebral hemorrhage and thromboembolic events.9,10 Infection is a life-threatening complication for VAD patients. The need for an external cannula is one of the main causes of infectious complications. In our series, the frequency and severity of significant device-related infections were reasonable. In conclusion, the Berlin Heart EXCOR was an effective and safe device. The implantation procedure and perioperative management were relatively easy. The system generated sufficient flow and cardiac output to achieve an acceptable level of quality of life and exercise capacity. Vital organ function could be protected for long support periods. Importantly, it can be used in patients of all ages, especially those in critical conditions like Intermacs levels 1 and 2. Our experience with EXCOR revealed important progress in the management of heart failure patients. REFERENCES 1. Stehlik J, Edwards LB, Kucheryavaya AY, et al. The registry of the International Society for Heart and Lung Transplantation: 29th Official Adult Heart Transplant Report—2012. J Heart Lung Transplant. 2012;31:1052–1064.
1016 2. Kirklin JK, Naftel DC, Kormos RL, et al. The Fourth INTERMACS Annual Report: 4,000 implants and counting. J Heart Lung Transplant. 2012;31:117–126. 3. Mikus E, Stepanenko A, Krabatsch T, et al. Reversibility of fixed pulmonary hypertension in left ventricular assist device support recipients. Eur J Cardiothorac Surg. 2011;40(4):971–977. 4. Ayik F, Oguz E, Engin C, et al. Surgical therapy of end-stage heart failure in pediatric patients. Transplant Proc. 2011;43:935– 937. 5. Fraser CD Jr, Jaquiss RD, Rosenthal DN, et al. Prospective trial of a pediatric ventricular assist device. N Engl J Med. 2012; 367:532–541.
OZBARAN, YAGDI, ENGIN ET AL 6. Schmid C, Tjan T, Etz C, et al. The excor device - revival of an old system with excellent results. Thorac Cardiovasc Surg. 2006;54:393–399. 7. Aggarwal S, Pagani FD. Bridge to transplantation: current outcomes. J Card Surg. 2010;25:455– 461. 8. Ramakrishna H, Jaroszewski DE, Arabia FA. Adult cardiac transplantation: a review of perioperative management (part-II). Ann Card Anaesth. 2009;12:155–165. 9. Birks EJ. Left ventricular assist devices. Heart. 2010;96:63–71. 10. Yagdi T, Oguz E, Engin C, et al. Changing face of heart failure surgery. Transplant Proc. 2012;44:1729 –1731.
