Implantation technique for the CardioWest total artificial heart

Current and future options for adult biventricular assistance: a review of literature

In cardiogenic shock various short-term mechanical assistances may be employed, including an Extra Corporeal Membrane Oxygenator and other non-dischargeable devices. Once hemodynamic stabilization is achieved and the patient evolves towards a persisting biventricular dysfunction or an underlying long-standing end-stage disease is present, aside from Orthotopic Heart Transplantation, a limited number of long-term therapeutic options may be offered. So far, only the Syncardia Total Artificial Heart and the Berlin Heart EXCOR (which is not approved for adult use in the United States unlike in Europe) are available for extensive implantation. In addition to this, the strategy providing two continuous-flow Left Ventricular Assist Devices is still off-label despite its widespread use. Nevertheless, every solution ensures at best a 70% survival rate (reflecting both the severity of the condition and the limits of mechanical support) with patients suffering from heavy complications and a poor quality of life. The aim of the present paper is to summarize the features, implantation techniques, and results of current devices used for adult Biventricular Mechanical Circulatory Support, as well as a glance to future options.

A heart transplant after total artificial heart support: initial and long-term results

OBJECTIVES

At our centre, the SynCardia temporary Total Artificial Heart (TAH-t) (SynCardia Systems, LLC, Tucson, AZ, USA) is used to provide long-term support for patients with biventricular failure as a bridge to a transplant. However, a heart transplant (HT) after such support remains challenging. The aim of this retrospective study was to assess the immediate and long-term results following an HT in the cohort of patients who had a TAH-t implant.

METHODS

A total of 73 patients were implanted with the TAH-t between 1988 and 2019 in our centre. Of these 73 consecutive patients, 50 (68%) received an HT and are included in this retrospective analysis of prospectively collected data.

RESULTS

In the selected cohort, in-hospital mortality after an HT was 10% (n = 5). The median intensive care unit stay was 33 days (range 5-278). The median hospital stay was 41 days (range 28-650). A partial or total pericardiectomy was performed during the HT procedure in 21 patients (42%) due to a severe pericardial reaction. Long-term survival rates after an HT at 5, 10 and 12 years were 79.1 ± 5.9% (n = 32), 76.5 ± 6.3% (n = 22) and 72.4 ± 7.1% (n = 12), respectively, which was similar to the long-term survival for a primary HT without TAH-t during the same period (n = 686). An HT performed within 3-6 months post-TAH-t implantation appeared to provide the best survival (P = 0.007). Eight (16%) patients required chronic dialysis during the subsequent follow-up period, with 3 patients requiring a kidney transplant.

CONCLUSIONS

The long-term outcomes with the SynCardia TAH-t as a bridge to transplant in patients with severe biventricular failure are very encouraging. Our review noted that an HT following TAH-t can be technically challenging, especially in the case of a severe pericardial reaction, with potential pitfalls that should be recognized preoperatively.

Insertion of the total artificial heart in the Fontan circulation

Though the Fontan circulation provides long-term palliation for patients with univentricular hearts, failure of the circulation may ensue, leaving heart transplantation as the only definitive treatment. For Fontan patients awaiting transplant, both "right-sided" and "left-sided" symptoms may be present and severe, hence, biventricular mechanical circulatory support may be indicated. This can be provided by implantation of the total artificial heart (TAH), a procedure which is performed slightly differently than in patients with biventricular hearts. In this article, the unique aspects of implantation of this device in a patient with a Fontan operation are reviewed, with specific attention to the most commonly encountered anatomic variants of importance to the implanting surgeon.

Experience with the SynCardia total artificial heart in a Canadian centre

BACKGROUND

The SynCardia total artificial heart (TAH) provides complete circulatory support by replacing both native ventricles. Accepted indications include bridge to transplantation and destination therapy. We review our experience with TAH implantation during a period when axial flow pump became available.

METHODS

We retrospectively analyzed the demographics, clinical characteristics and survival of all patients receiving the TAH.

RESULTS

From September 2004 to November 2016, 13 patients (12 men, mean age 45 ± 13 yr) received the TAH for refractory cardiogenic shock secondary to idiopathic (56%) or ischemic (17%) cardiomyopathy and to other various causes (33%). Before implantation, mean ejection fraction was 14% ± 4%, 7 (54%) patients had previous cardiac surgery, 4 (31%) were on mechanical ventilation, and 3 (23%) patients were on dialysis. The mean duration of TAH support was 46 ± 40 days. Three (23%) patients died while on support after a mean of 15 days. Actuarial survival on support was 77% ± 12% at 30 days after implantation. Complications on support included stroke (n = 1, 8%), acute respiratory distress syndrome requiring prolonged intubation (n = 5, 38%) and acute renal failure requiring temporary dialysis (n = 5, 38%). Ten (77%) patients survived to be transplanted after a mean of 52 ± 42 days of support. Actuarial survival rates after transplant were 67% ± 16% at 1 month and 56% ± 17% at 1 year after transplantation.

CONCLUSION

The TAH provides an alternative with low incidence of neurologic events in extremely fragile and complex patients waiting for heart transplantation. Complex and unusual anatomic conditions explained the current use of TAH.

Pulmonary arteriovenous extracorporeal membrane oxygenation to avoid pulmonary overflow during total artificial heart implantation

Total artificial hearts (TAH) can be used as a bridge to transplant or, occasionally, as destination therapy for patients with severe biventricular dysfunction. Not infrequently TAHs are placed in patients with severe low flow states, in which the lungs of these patients are unable to adjust rapidly to the "normal" right ventricular output of a TAH. These patients may develop variable degrees of pulmonary edema secondary to stress failure of the pulmonary capillaries requiring increased respiratory support, which can occasionally be fatal. In this "how to do it" article, we describe the technique for a pulmonary arteriovenous extracorporeal membrane oxygenation with TAH to avoid sudden pulmonary overflow and gradually expose the lungs to increasing flow.

Perioperative Care of the Patient With the Total Artificial Heart

Advanced heart failure continues to be a leading cause of morbidity and mortality despite improvements in pharmacologic therapy. High demand for cardiac transplantation and shortage of donor organs have led to an increase in the utilization of mechanical circulatory support devices. The total artificial heart is an effective biventricular assist device that may be used as a bridge to transplant and that is being studied for destination therapy. This review discusses the history, indications, and perioperative management of the total artificial heart with emphasis on the postoperative concerns.

Results with SynCardia total artificial heart beyond 1 year

Mechanical circulatory support devices have been increasingly used for long-term support. We reviewed outcomes in all patients supported with a SynCardia total artificial heart (TAH) for more than 1 year to assess its safety in long-term support. As of December 2011, all 47 patients who received the TAH from 10 centers worldwide were included in this retrospective study. Clinical data were collected on survival, infections, thromboembolic and hemorrhagic events, device failures, and antithrombotic therapy. The mean age of patients was 50 ± 1.57 years, the median support time was 554 days (range 365-1373 days). The primary diagnosis was dilated cardiomiopathy in 23 patients, ischemic in 15, and "other" in 9. After a minimum of 1 year of support, 34 patients (72%) were successfully transplanted, 12 patients (24%) died while on device support, and 1 patient (2%) is still supported. Five patients (10%) had a device failure reported. Major complications were as follows: systemic infections in 25 patients (53%), driveline infections in 13 patients (27%), thromboembolic events in 9 patients (19%), and hemorrhagic events in 7 patients (14%). SynCardia TAH has proven to be a reliable and effective device in replacing the entire heart. In patients who reached a minimum of 1 year of support, device failure rate is acceptable and only in two cases was the leading cause of death. Infections and hemorrhagic events were the major causes of death. Patients who remain supported beyond 1 year are still likely to survive to transplantation.

Cardiac Assist Devices and Hemodialysis Catheter Procedures - What Do the Nephrologists Need to Know?

The use of ventricular assist devices (VAD) and total artificial heart (TAH) is increasing rapidly, and a large proportion of these device recipients already have or will develop severe renal dysfunction at the time of device implantation. As a consequence, nephrologists are becoming more and more involved in the care of this challenging population. As nephrologists take upon themselves many aspects of dialysis vascular access care, they need to be familiar with the special circumstances of performing hemodialysis catheter procedures in these patients. This review describes the important characteristics of these devices that have serious implications for the technique of placing or replacing dialysis catheters. These implications apply for both tunneled and nontunneled dialysis catheters and so concern all nephrologists, not only the interventionalists. We describe the important anatomical factors, anticoagulation management, device management, vascular access management and technical considerations of placing or replacing tunneled and nontunneled hemodialysis catheters from the perspective of a nephrologist establishing and maintaining lifesaving dialysis vascular access. Without a good understanding of these devices, serious consequences such as VAD rotor damage or blockage, or artificial heart valve blockage or damage can occur. These artificial devices are lifesaving, and any such complication is unacceptable. This review describes steps to minimize the risks.

Implantation of the syncardia total artificial heart

With advances in technology, the use of mechanical circulatory support devices for end stage heart failure has rapidly increased. The vast majority of such patients are generally well served by left ventricular assist devices (LVADs). However, a subset of patients with late stage biventricular failure or other significant anatomic lesions are not adequately treated by isolated left ventricular mechanical support. Examples of concomitant cardiac pathology that may be better treated by resection and TAH replacement includes: post infarction ventricular septal defect, aortic root aneurysm / dissection, cardiac allograft failure, massive ventricular thrombus, refractory malignant arrhythmias (independent of filling pressures), hypertrophic / restrictive cardiomyopathy, and complex congenital heart disease. Patients often present with cardiogenic shock and multi system organ dysfunction. Excision of both ventricles and orthotopic replacement with a total artificial heart (TAH) is an effective, albeit extreme, therapy for rapid restoration of blood flow and resuscitation. Perioperative management is focused on end organ resuscitation and physical rehabilitation. In addition to the usual concerns of infection, bleeding, and thromboembolism common to all mechanically supported patients, TAH patients face unique risks with regard to renal failure and anemia. Supplementation of the abrupt decrease in brain natriuretic peptide following ventriculectomy appears to have protective renal effects. Anemia following TAH implantation can be profound and persistent. Nonetheless, the anemia is generally well tolerated and transfusion are limited to avoid HLA sensitization. Until recently, TAH patients were confined as inpatients tethered to a 500 lb pneumatic console driver. Recent introduction of a backpack sized portable driver (currently under clinical trial) has enabled patients to be discharged home and even return to work. Despite the profound presentation of these sick patients, there is a 79-87% success in bridge to transplantation.

Total artificial heart in the pediatric patient with biventricular heart failure

Mechanical circulatory support emerged for the pediatric population in the late 1980s as a bridge to cardiac transplantation. The Total Artificial Heart (TAH-t) (SynCardia Systems Inc., Tuscon, AZ) has been approved for compassionate use by the Food and Drug Administration for patients with end-stage biventricular heart failure as a bridge to heart transplantation since 1985 and has had FDA approval since 2004. However, of the 1,061 patients placed on the TAH-t, only 21 (2%) were under the age 18. SynCardia Systems, Inc. recommends a minimum patient body surface area (BSA) of 1.7 m(2), thus, limiting pediatric application of this device. This unique case report shares this pediatric institution's first experience with the TAH-t. A 14-year-old male was admitted with dilated cardiomyopathy and severe biventricular heart failure. The patient rapidly decompensated, requiring extracorporeal life support. An echocardiogram revealed severe biventricular dysfunction and diffuse clot formation in the left ventricle and outflow tract. The decision was made to transition to biventricular assist device. The biventricular failure and clot formation helped guide the team to the TAH-t, in spite of a BSA (1.5 m(2)) below the recommendation of 1.7 m(2). A computed tomography (CT) scan of the thorax, in conjunction with a novel three-dimensional (3D) modeling system and team, assisted in determining appropriate fit. Chest CT and 3D modeling following implantation were utilized to determine all major vascular structures were unobstructed and the bronchi were open. The virtual 3D model confirmed appropriate device fit with no evidence of compression to the left pulmonary veins. The postoperative course was complicated by a left lung opacification. The left lung anomalies proved to be atelectasis and improved with aggressive recruitment maneuvers. The patient was supported for 11 days prior to transplantation. Chest CT and 3D modeling were crucial in assessing whether the device would fit, as well as postoperative complications in this smaller pediatric patient.

Use of a Totally Artificial Heart for a Complex Postinfarction Ventricular Septal Defect

The incidence of cardiac rupture complicating myocardial infarction has declined since the introduction of thrombolytic therapy. Despite the advances in the management of myocardial infarction, cardiac rupture remains an important cause of death among infarction-related fatalities. We discuss a patient who presented to our hospital with myocardial infarction and who subsequently developed a complex ventricular septal rupture, for which surgical repair was not feasible. Implantation of a CardioWest Total Artificial Heart (SynCardia Systems) allowed for immediate hemodynamic stabilization and served as a bridge to transplantation.

CardioWest temporary total artificial heart

BACKGROUND

The CardioWest temporary total artificial heart (TAH-t) replaces both native ventricles of the heart and is more beneficial for a select group of patients than most other typical ventricular assist devices (VADs). This review will expand on the current literature and highlight the chronology of this device. The CardioWest TAH-t has been implanted in over 715 patients at 30 multiple institutional centers worldwide as a bridge-to-transplant (BTT) since 1993. The mechanical flow dynamics of the device are manufactured and designed differently from other traditional VADs, allowing increased outputs and normal filling pressures, allowing for sufficient organ and tissue perfusion and dramatic recoveries, allowing patients to return to an almost normal quality of life.

RESULTS

There was a 79% survival to transplant achievement in the protocol group who received the TAH-t versus a 46% in the control group (P < 0.001). Furthermore, there was a 70% survival rate at one year in the protocol group versus 31% in the control group (P < 0.001). The one- and five-year survival rates after transplantation were 69% and 34%, respectively, in the control group and 86% and 64%, respectively, in the protocol group.

CONCLUSION

It is evident that the advancement of modern engineering and medicine has made way for a reliable and durable device that provides a promising future in the field of end-stage heart failure.

Total artificial heart--concepts and clinical use

End-stage congestive heart failure remains the leading cause of death in the United States. Despite advances in medical treatment, it also remains the most common reason for admission to the hospital. The gold standard of treatment for the failing heart, orthotopic heart transplantation, is limited by a shortage of donor hearts. There are also a significant number of patients who are not transplant candidates due to comorbid conditions and/or inability to tolerate immunosuppressive therapy. To meet the need for this latter group, the medical field has embraced ventricular assist device (VAD) therapy to extend survival and improve quality-of-life for the end-stage cardiac patient. This therapy, however, has been currently limited to the failing left ventricle and is still fraught with complications that limit long-term and widespread use. The total artificial heart, as currently available with two devices, is rapidly becoming the treatment of choice for biventricular failure.

Implantation of Cardio West Total Artificial Heart for Irreversible Acute Myocardial Infarction Shock

Patients who develop cardiogenic shock after acute myocardial infarction have a very high mortality rate despite early reperfusion therapy. Hemodynamic stabilization can often only be achieved by implanting a mechanical circulatory support system. When, in cases representing expansive myocardial impairment without any chance of recovery, pharmacological therapy and the use of percutaneous assist devices have failed, the implantation of a total artificial heart is indicated. We report our first experiences with this extensive and innovative method of managing irreversible cardiogenic shock patients. The CardioWest total artificial heart was implanted in 5 patients (male; mean age, 50 years). All patients were in irreversible cardiogenic shock despite maximum dosages of catecholamines, an intra-aortic balloon pump and/or a femoro-femoral bypass. In all patients early reperfusion therapy was performed. After implantation of the Cardio West system, all dysfunctional organ systems rapidly recovered in all patients. Four of 5 patients underwent successful heart transplantation after a mean support time of 156 days. One patient died because of enterocolic necroses caused by an embolic event after termination of dicumarol therapy. In summary, our first experiences justify this extensive management in young patients who would otherwise have died within a few hours.

CardioWest Total Artificial Heart in a Moribund Adolescent With Left Ventricular Thrombi

Bridge to transplant is a well-known strategy to enable patients with congestive heart failure to live until transplant. A 15-year-old boy with Beckers' muscular dystrophy and cardiomyopathy was accepted for heart transplantation. He suffered a cardiac arrest and was placed on extracorporeal membrane oxygenator. A paracorporeal biventricular assist device and a total artificial heart were considered for bridge to transplant. A CardioWest total artificial heart was chosen because of the patient's size. Multiple left ventricular thrombi were identified at the time of the ventriculectomy. The patient did well with the total artificial heart was transplanted and discharged home. The unknown presence of significant left ventricular thrombi raises the question of outcome with a paracorporeal ventricular assist device.

Patients With a Body Surface Area Less Than 1.7 m2 Have a Good Outcome With the CardioWest Total Artificial Heart

BACKGROUND

A body surface area (BSA) of 1.7 m2 was considered as the lower limit to implant a CardioWest Total Artificial Heart (TAH). We reviewed our experience with the TAH in patients with a BSA of less than 1.7 m2.

METHODS

From April 1986 to May 2003, among 149 patients implanted with a TAH in our institution, 30 had a BSA of less than 1.7 m2 (Group I). Results were compared with the remaining 119 patients (Group II).

RESULTS

One patient in Group I experienced a fitting problem and was left with the chest open. Otherwise, in this group, the Day 1 cardiac index averaged 3.6 +/- 0.6 liter/min/m2, which was significantly higher than the 2.8 +/- 0.36 liter/min/m2 observed in Group II. Post-implantation central venous pressure and mean arterial pressure were similar in both groups: 14.7 +/- 3.8 mm Hg vs 14.5 +/- 4 mm Hg and 87 +/- 23 mm Hg vs 88 +/- 19 mm Hg, respectively. In Group I, survival on the device dramatically increased from 9% before 1992, to 36% between 1992 and 1997 and finally reached 75% after then. In the meantime, for the same time periods, global survival to hospital discharge increased from 9% to 36% and reached 50% after 1997. In Group II, global survival to hospital discharge was 25.5% before 1992, 34.6% between 1993 and 1997, and reached 52% thereafter.

CONCLUSION

The CardioWest TAH can be used in patients with a BSA between 1.5 m2 and 1.7 m2 with few fitting problems. In this group of patients, results are similar to those obtained in patients with a BSA greater than 1.8 m2.

Total artificial heart bridge to transplantation: a 9-year experience with 62 patients

BACKGROUND

The SynCardia CardioWest total artificial heart (CardioWest TAH) is a biventricular, orthotopic, pneumatic, pulsatile blood pump driven by an external console. For each ventricle, the length of the blood-flow path is shorter and the inflow and outflow valves are larger than in any other bridge-to-transplant device, resulting in greater blood flow at smaller pre-load. Such a device should be optimal for bridging transplant candidates who have biventricular failure and for whom all other therapies have failed.

METHODS

From January 1, 1993, to April 1, 2002, we prospectively studied 62 consecutive CardioWest TAH implant recipients to document safety and efficacy in bridge to transplantation. We used multisystem monitoring and multidrug therapy for anti-coagulation in 58 patients starting September 1, 1994.

RESULTS

Before implantation, patients were critically ill with biventricular heart failure. Mortality in this group from the time of implantation until transplantation was 23%. Causes of death during device support included multi-organ failure (6), sepsis (3), and valve entrapment (2). Forty-eight patients underwent transplantation (77%). Forty-two survived to hospital discharge (68% of the total, 88% of those undergoing transplantation). Adverse events included bleeding (20%), device malfunction (5%), fit complications (3%), mediastinal infections (5%), visceral embolus (1.6%), and stroke during support (1.6%). The linearized stroke rate was 0.068 events per patient-year.

CONCLUSIONS

Sixty-eight percent of critically ill transplant candidates for whom medical therapy failed were bridged to transplantation with the CardioWest TAH and survived long-term. Most deaths that occurred during device support were related to pre-implant problems. Infection and stroke were rare events. Therefore, we recommend the CardioWest TAH as the biventricular bridge-to-transplant device of choice.

Improved Early Survival with the Total Artificial Heart

We report our experience with the total artificial heart (TAH) to determine if outcomes have improved. Thirty-one patients received the TAH as a bridge to transplant and were divided into the two groups A (eighteen implanted in the first eight years) and B (thirteen implanted in the last eight years). Changes in management included immediate sternal closure, early extubation, delayed transplant listing, early rehabilitation, and measurement of preformed antibodies. The infection rate in B was lower than in A, both during support (31% versus 39%) and following transplant (38% versus 72%), and rejection was lower in B than in A (0% versus 44%). There was no difference in neurological events between groups; however, reopening was more frequent in B (61% versus 28%). Hospital survival increased from 61% in A to 85% in B; however, this was not statistically significant. We hypothesize that this improvement was likely due to changes in patient management.

Successful management of empyema in a patient with a total artificial heart

A description of successful management of a patient who developed an empyema as a postoperative complication following the insertion of a CardioWest total artificial heart (TAH) as a bridge to cardiac transplantation is presented. By using traditional methods of management, the patient recovered and went on to transplant.

Surgical treatment for chronic heart failure

Advances in the surgical treatment of chronic heart failure including ventricular re-modeling, artificial heart technology and bridge to recovery have revolutionized cardiac surgical management. This article summarizes the most popular surgical treatment of heart failure with experiences from various institutes.

Total artificial hearts: bridge to transplantation

The CardioWest TAH was created and initially tested at the same time as the Thoratec, Novacor, and HeartMate devices. It was designed as a permanent artificial heart and was the first-ever mechanical circulatory device to be used as destination therapy. Twenty years have passed since that early experience. Pneumatic technology is still current and being developed as in existing or new implantable Thoratec VADs the pneumatic HeartMate, and the Abiomed BVS 5000 pumps. Portable pneumatic drivers have been available since 1982, and in recent times have allowed discharge to home of substantial numbers of patients, thus reducing the length of hospital stays and making mechanical device support less expensive to society and more tolerable to patients. Within months, a portable driver for the CardioWest will be available. The documented benefits of the CardioWest TAH include rescue of: critically ill patients with advanced heart failure; patients with biventricular failure especially those with significant right heart failure, elevated pulmonary vascular resistance, or pulmonary edema; patients with renal or hepatic failure secondary to low cardiac output; patients with massive myocardial damage such as those with post-\infarction VSD or irreversible cardiac graft rejection; patients with mechanical valves or native valve disease; and patients with intractable arrhythmias and heart failure. High device outputs with restoration of normal filling pressures result in high perfusion pressures that have led to dramatic recoveries, convalescence, and return to levels of activity compatible with normal life. The average device output with the CardioWest TAH is higher than any other approved or investigational device. The reason for this resides in design simplicity this device has the shortest and largest inflow pathway. Stroke, in the authors' own series, is rare with a linearized rate of 0.068 events per patient year. If the experiences of La Pitie and the University of Arizona are combined, there has been one stroke in 25 patient years (0.04 events/patient year). Serious infections have been rare (12% of patients). No clinical mediastinitis has occurred. Drivelines have healed in tightly and never caused an "ascending" infection. There has not been a case of device endocarditis. Using a broad definition of bleeding, including takeback reoperation for bleeding, bleeding more than 8 units in the first postoperative 24 hours or 5 units over any other 48-hour period, a 25% to 36% incidence has been documented. No cases of fatal exsanguination have resulted, as there have been with the HeartMate. The incidence of bleeding as an adverse event is about 17% lower than the rate reported for the HeartMate VE LVAD, and it is about the same as that reported for Novacor and for Thoratec. Implantation of this device is relatively easy and often done (with attending help) by the authors' residents. If one follows the guidelines for fitting the device, and takes the recommended advice for implantation, hemostasis is excellent and restoration of immediate cardiac function with high flows is nearly automatic. Use of a neopericardium of 0.1 mm EPTFE at the time of implantation assures atraumatic and relatively quick re-entry for transplantation and prevents the normal inflammatory mediastinal reaction that might be desirable in a destination application. In selected patients the CardioWest TAH is the device of choice for bridge to transplantation. When a portable driver becomes available, out of hospital management of CardioWest TAH patients will be feasible and consideration of use of this device for longer term applications, (e.g., "destination therapy,") will be reasonable. A wearable driver, even smaller than a portable, will improve quality of life and expand the patient population that may be therapeutically served with this system. In short, the CardioWest TAH has come nearly full circle. It was first used as a destination device. It has since been used as a bridge to transplantation in nearly 200 patients as the Jarvik-7/Symbion TAH and, since 1993, in over 225 patients as CardioWest. The results have improved with time. Thromboembolism and infection rates have been competitive with currently available devices. Device reliability and durability have been excellent. Survival rates have been very high in a group of perhaps the sickest patients to be supported with any pulsatile device. Pneumatic technology has improved with portability and miniaturization, and there is reason to believe that it will become even better. Application of modern manufacturing techniques to this very simple device raises the possibility of significant manufacturing cost reduction, in an era of prohibitive cost for other devices. All of this establishes the CardioWest as a valuable device for any program that is seriously interested in end-stage heart disease and a likely device for permanent use in appropriately selected patients.

Synthetic membrane neo-pericardium facilitates total artificial heart explantation

BACKGROUND

In the past, explantation of the Cardio West total artificial heart (TAH) has been technically challenging because of the presence of dense adhesions and extremely thickened pericardium. To prevent this, we constructed a synthetic neo-pericardium in 14 patients.

METHODS

Using expanded polytetrafluoroethylene (e-PTFE) membrane, we constructed a pericardium within the pericardium, or "neo-pericardium," completely covering the Cardio West TAH separating the native atria from the native pericardium, and wrapping the ascending aorta from the outflow conduit distally for about 5 to 7 cm.

RESULTS

Of the 14 patients, 9 were transplanted and could be evaluated, 3 died on device support, and 2 are currently on device support. In each case, we attained faster (by 25 minutes) and easier reentry through the sternum. Surgical planes around the aorta, over the right and left atria, and throughout the pericardial space became apparent immediately after e-PTFE membrane removal. The pericardium and related tissues although slightly thickened (<2 mm) were pliable compared with our previous 36 patients, with very thick adherent pericardium over the device and native atria.

CONCLUSIONS

The plastic materials forming the ventricular housing and drivelines of the Cardio West TAH and the Dacron outflow conduits have in the past caused profound local inflammatory reactions, resulting in extremely dense adhesions and thickened adherent pericardium. Using e-PTFE membrane to fashion a complete neo-pericardium and to wrap the ascending aorta at the time of Cardio West implantation dramatically reduces adhesions and pericardial thickening and facilitates explantation.

Update on the total artificial heart

There has been a quest for an artificial organ that can replace the heart for decades. Remarkable advances were made in the second half of the twentieth century in the fields of medicine and engineering that led to the development of several devices with the intention of totally replacing the human heart. Some of these devices, like the Jarvik artificial heart, were utilized initially as a permanent replacement for the failing heart. It became more successful as a bridge to heart transplantation (BTT) in the years that followed its introduction. Currently the CardioWest total artificial heart (TAH) is the only device in clinical use with the intention of bridging patients to heart transplantation. Two new TAHs are being developed with the intention of being used as an alternative to transplantation (ATT) or on a permanent basis. The next 100 years will bring revolutionary new designs and advances in the field of end stage heart disease that may only be ideas at the present time.

Surgical treatment of chronic heart failure. What to tell patients about heart-saving options

Patients with severe, chronic heart failure can be managed by several surgical techniques that lead to cure for some or provide a bridge to heart transplantation for others. Although transplantation is currently the only proved curative therapy for end-stage heart failure, the supply of donor hearts has not kept pace with the demand. Therefore, procedures such as reduction ventriculoplasty, transmyocardial laser revascularization, or dynamic cardiomyoplasty and the use of assist devices or artificial hearts hold promise for helping patients maintain heart function until a cure can be offered.

The CardioWest total artificial heart as a bridge to transplantation

The CardioWest total artificial heart (TAH), formerly known as the Jarvik-7 and then the Symbion heart, is the only TAH in current clinical use. A new study, approved by the Food and Drug Administration (FDA), was initiated in 1993 with the goal of approving this pump for commercial release. Since then, 145 CardioWest TAHs have been implanted, including 37 pumps in 36 patients at our center. Our 36 patients were studied prospectively according to the investigational device exemption protocol approved by the FDA. Clinical and hemodynamic data obtained upon patients' entry into the study identified this group as mortally ill. After receiving a CardioWest TAH, 29 of the 36 patients (81%) survived to heart transplantation, and 26 (72% of the total group and 90% of the transplant recipients) have survived for up to 7 years (average, 24 months). Multicomponent anticoagulation, based on readily available tests, and the intrinsic properties of the TAH have resulted in a low linearized stroke rate of 0.48 event per patient-year. There have been no device-related mediastinal infections. In dying patients with nonexistent or severely compromised biventricular function, the CardioWest TAH has proved safe and effective, allowing a 72% survival rate for an average of 24 months.

Arizona experience with CardioWest Total Artificial Heart bridge to transplantation

BACKGROUND

We hypothesized that bridge to transplantation with the CardioWest Total Artificial Heart would succeed in a large percentage of patients. Further, we hypothesized that this success rate would not be significantly decreased by infection or thromboembolism.

METHODS

From 1993 to March 1999, 24 patients received implants with the intention of bridge to transplantation. Data were collected prospectively. Heparin, coumadin, aspirin, ticlopidine, dipyridamole, and pentoxifylline were used for anticoagulation.

RESULTS

Four patients died while on device support. Nineteen of 23 patients (83%) were transplanted. All 19 survived long term. One patient remains on CardioWest Total Artificial Heart support 6 weeks after implant. There was one stroke on the day of transplantation. There was a second stroke on the day of implantation. Neither stroke caused significant residual deficits. Both were in close relationship to an operative procedure. There were no serious device-related infections.

CONCLUSIONS

The CardioWest Total Artificial Heart salvaged 20 of 24 critically ill patients. Neither infections nor neurologic problems were significant. We believe it is the device of choice for decompensating patients with biventricular failure who have adequate body and heart size.