The failing Fontan: what's NEXT...?

The Fontan procedure represents the final stage of the transition to single ventricle physiology. Conversion of very complex congenital heart anatomy, such as hypoplastic left heart syndrome, double-outlet right ventricle or double-inlet left ventricle, to a single ventricle has grown in popularity as morbidity and mortality have improved. As these patients grow, survivors are at risk for impaired ventricular dysfunction, plastic bronchitis, protein-losing enteropathy and late failure. Late failing Fontan patients represent a particularly vexing scenario for clinicians, as the only durable treatment option is cardiac transplantation. However, in the short-term, some of these patients require support beyond medical management, with mechanical circulatory support via extracorporeal life support or a ventricular assist device. We report the successful bridge of an adolescent female post-Fontan conversion with late severe cardiac failure. The patient was initially resuscitated with extracorporeal life support, transitioned to a single Berlin Heart EXCOR® ventricular assist device and, subsequently, underwent successful cardiac 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.

Errors in pressure gradient measurement by continuous wave Doppler ultrasound: type, size and age effects in bioprosthetic aortic valves.

The accuracy of continuous wave Doppler ultrasound in deriving pressure gradients across bioprosthetic heart valves was evaluated in an in vitro pulse duplicator. Simultaneous pressure transducer and Doppler measurements were made in new and explanted aortic bioprosthetic valves of several sizes and four types: Carpentier-Edwards, Ionescu-Shiley, Hancock standard and Hancock modified. The mean and peak gradients calculated by the modified Bernoulli equation from Doppler velocity measurements were always greater than those measured manometrically, despite corrections for location dependence of the manometric gradient (or pressure recovery). The relation between manometric and ultrasonically determined gradient was found to be statistically dependent on the valve type (mean gradient p less than 0.0001; peak gradient p = 0.0003) and size (mean gradient p = 0.0089; peak gradient p = 0.0107). Effects of implantation were observed, but were not shown to be significant. It is concluded that the continuous wave Doppler velocity data overestimated prosthetic valve pressure gradient in all cases, even when pressure recovery was taken into account. Clinicians should be wary of Doppler data when making major diagnostic or therapeutic decisions.

Management of complications of Sideris transcatheter devices for atrial septal defect closure.

Various devices that can be inserted transvenously to close an ostium secundum atrial septal defect are undergoing clinical trials. Although these are safe and effective in most instances, they may occasionally dislodge or fail to "button" properly, causing migration and embolization. We report two cases in which the occluder and counteroccluder of the Sideris device for transvenous atrial septal defect occlusion (Custom Medical Devices, Amarillo, Tex.) failed to "button" appropriately, migrating in the right atrium in one patient and embolizing to the pulmonary artery in the second patient. An emergency operation was required to retrieve the device and repair the atrial septal defect.

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.

Correlation of clinical embolic events with coagulability in a patient with a total artificial heart.

A 46-year-old female patient was supported for 185 days with a total artificial heart, underwent successful transplantation, and survived for over 1 year with no clinical residual findings suggestive of embolic events. Daily observation, analysis of a large battery of coagulation tests, and eight serial computed tomographic scans suggest that she had 12 embolic events while receiving mechanical support. Furthermore, it appears that the events were associated temporally with several mild infections and that coagulation was stimulated several days to 1 week before we detected the events.

Blood loss and transfusion requirements in patients implanted with a mechanical circulatory support device undergoing cardiac transplantation.

Patients implanted with mechanical circulatory support devices (MCSD's) are at high risk for post-operative bleeding at cardiac transplantation. However, the magnitude of the risk and transfusion requirements for MCSD patients at the time of transplantation have not been previously reported. The purpose of this study was to characterize and compare the bleeding characteristics and transfusion requirements of 3 sub-groups of cardiac transplant patients: primary (n = 45), redo (n = 26), and MCSD (n = 23) patients.

Bridge to transplantation with the CardioWest total artificial heart: the international experience 1993 to 1995.

BACKGROUND: After reapproval by the Food and Drug Administration of the CardioWest total artificial heart for clinical investigation, an international study was started in January 1993 to ascertain the safety and efficacy of this device for bridging to heart transplantation. To date, 40 devices have been implanted in five centers. METHODS: Retrospective data collection from participating centers provided enough material for analysis of patient selection, patient survival, adverse events, and comparison with contemporary devices used for bridge to transplantation. RESULTS AND CONCLUSIONS: Twelve patients (30%) died after implantation and before transplantation after an average of 10.6 +/- 10 days of support. The major cause of death in this group was multiorgan failure. Twenty-eight patients (70%) were supported 36 +/- 36 days before transplantation. There were two deaths after transplantation (1 rejection, 1 multiorgan failure) leaving 26 patients (65% of the total patients and 93% of those who were transplanted) who survived to discharge from the hospital. There was one late death from rejection at one month post discharge. The mean survival time of the 25 surviving patients is 12 months. These results compare favorably with those of other contemporary devices used for bridge to transplantation.

Is it necessary to perform surveillance endomyocardial biopsies in heart transplant recipients?

BACKGROUND: Routine surveillance endomyocardial biopsies to diagnose unsuspected rejection are performed at 3- to 12-month intervals after heart transplantation. From 1979 to 1989, surveillance biopsies were routinely performed as a part of the yearly evaluation. METHODS: A retrospective analysis of the follow-up data showed that "routine surveillance biopsies" had an extremely low yield, and, on the basis of the results of this study, we discontinued to perform surveillance biopsies beyond 6 months after transplantation. To validate these results, we compared the outcome of two groups of patients who had similar demographics and identical immunosuppression, except that in one group the surveillance biopsies were not performed. RESULTS: No difference was found in either actuarial survival rate or freedom from late rejection between the two groups. CONCLUSIONS: These findings confirm that routine surveillance heart biopsies beyond 6 months after transplantation are not necessary and they should be performed only if there is clinical suspicion of rejection or as part of a research protocol.

Implantation technique for the CardioWest total artificial heart.

The CardioWest total artificial heart is a pneumatically driven device that totally replaces the failing ventricles. It is currently undergoing clinical investigation as a bridge to heart transplantation in several centers throughout the world. A bilateral ventriculectomy is performed and the device is implanted. Blood flows are usually maintained at 6-8 L/min. Approximately 130 patients have undergone bridge to transplant with this device. Patient selection and excellent surgical technique are required for a successful outcome. A detailed description of the implantation technique is presented to facilitate the use of this technology.

Bridge to transplantation with a Thoratec left ventricular assist device in a 17-kg child.

A Thoratec left ventricular assist device (LVAD) was used to support a 7-year-old 17-kg boy with viral cardiomyopathy for 23 days before heart transplantation. The boy is still living more than 1 year posttransplant, and functional except for some spastic paresis of the left hand, a residual from a stroke during device support. He is the smallest person to be supported with this device. We discuss techniques for using the Thoratec in children.

Endomyocardial biopsy in the heterotopic heart transplant patient.

We present a technique for rapid and easy endomyocardial biopsy of the heterotopic transplanted heart. With a recent resurgence in heterotopic heart transplantation, we believe that ours is a sound technique in obtaining both routine surveillance biopsies as well as evaluating "right-sided pressures" in the "piggy-back" heart.

Biventricular cannulation for the Thoratec ventricular assist device.

The Thoratec biventricular assist device has been used extensively as a bridge to heart transplantation. Right atrial cannulation has always been used during right ventricular support, however diminished filling and output of the right ventricular assist device have been noticed when compared with filling and output of the left ventricular assist device. We describe a technique to directly cannulate the right ventricle to maximize filling and output of the right ventricular assist device.

Incidence and recurrence of gastrointestinal cytomegalovirus infection in heart transplantation.

Cytomegalovirus (CMV) infection of the upper gastrointestinal tract is a major cause of morbidity in heart transplant recipients. Since April 1985, 201 patients underwent heart transplantation at our institution. Immunosuppressive therapy was with a triple drug regimen of cyclosporin A, prednisone, and azathioprine. Fifty-three of these patients had upper gastrointestinal symptoms, which primarily consisted of abdominal pain or nausea and vomiting despite prophylactic treatment with antacids, H2 blockers, or both. A total of 79 esophagogastroduodenoscopies were performed in this group; 15 patients required more than one esophagogastroduodenoscopy for recurrent symptoms. Of these 53 patients with persistent gastrointestinal symptoms, 16 (30.2%) had diffuse erythema or ulceration of the gastric mucosa (14), esophagus (1), and duodenum (1) with biopsy results that were positive for CMV on viral cultures (incidence, 8%). All patients with positive biopsy results were treated with intravenous ganciclovir at a dose of 10 mg.kg-1.day-1 in two divided doses for a period of 2 weeks. Recurrence developed in 6 patients (37.5%) and necessitated repeated therapy with ganciclovir. None of the 16 patients died as a result of gastrointestinal CMV infection. Patients who were seronegative for CMV and received a seropositive heart experienced earlier clinical manifestation of CMV infection. Infection of the upper gastrointestinal tract with CMV is a major cause of morbidity in cardiac transplant patients that may progress to a life-threatening complication if left untreated. Early diagnosis with esophagogastroduodenoscopy and biopsy for viral cultures is essential for documentation and proper management.

Simplified technique of heart-lung transplantation.

Well-known complications of heart-lung transplantation include mediastinal bleeding and phrenic nerve injury. Conventional technique places the hila behind the phrenic nerves. We have placed the hila in front of the phrenic nerve in our last 10 patients, using direct caval anastomoses when feasible. This minimizes traction on and dissection around the phrenic nerves, and allows anterior rotation of the heart-lung block for easier hemostasis of the posterior mediastinum after implantation.

The CardioWest total artificial heart bridge to transplantation: 1993 to 1996 national trial.

BACKGROUND: We performed a controlled study of a total artificial heart in bridge to transplantation. We hypothesized that the CardioWest total artificial heart used in a selected population of decompensating cardiac transplantation candidates would result in improved survival compared with matched controls. METHODS: The CardioWest trial started in 1993 in six United States institutions under an investigational device exemption from the Food and Drug Administration. Four centers contributed 27 implant and 18 matched retrospective control patients. RESULTS: Of the implant patients, 25 (93%) received a transplant, 24 (89% of the total, 96% of those transplanted) were discharged and are currently surviving. In the control group, 10 patients died awaiting transplantation, 8 received a transplant, and 7 were discharged with 6 surviving (p = 0.00001). All adverse events were documented with respect to time. Thirteen serious adverse events occurred, 11 of which occurred in the 2 patients that died during implant. CONCLUSIONS: In a selected group of patients with endstage heart disease, use of the CardioWest total artificial heart is lifesaving. When compared with the series of matched retrospective controls, a significant improvement in survival was found in the CardioWest implant group.

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.

Heart-lung transplantation in situs inversus.

Reconstruction was accomplished in a 2 heart-lung recipients with situs inversus resulting in a left-sided systemic venous atrium. We created a large common atrium that was closed on the left side, leaving an atrial cuff on the inferior right quadrant. To this we anastomosed the donor right atrium, which had been opened laterally between the cavae. This resulted in some clockwise rotation of the ventricles and anterior positioning of the apex. The right pulmonary veins passed superior to the atrial anastomosis and posterior to the donor right atrium. Cardiopulmonary function was excellent in both cases.

Comparison of the CardioWest total artificial heart, the novacor left ventricular assist system and the thoratec ventricular assist system in bridge to transplantation.

BACKGROUND: Device selection has historically been supported by minimal comparative data. Since 1994, we have implanted 43 patients with the CardioWest Total Artificial Heart (CW), 23 with the Novacor Left Ventricular Assist System (N), and 26 with the Thoratec Ventricular Assist System (T). This experience provides a basis for our device selection criteria. METHODS: We reviewed retrospectively the results for survival, stroke, and infection in the CW, N, and T groups. Statistical methods included the Student's t-test, chi2 analysis, and Kaplan-Meier actuarial survival curves. RESULTS: The T group patients were younger and smaller sized than the CW or N group. The CW group had the highest mean central venous pressure (CVP) and lowest mean cardiac index. Survival to transplantation was 75% for CW, 57% for N, and 38% for T. Multiple organ failure postimplant caused most deaths in the CW and T groups. Right heart failure and stroke caused most N deaths. Linearized stroke rates (event/patient-month) were 0.03 for CW, 0.28 for N, and 0.08 for T. Serious infections were found in 20% of CW, 30% of N, and 8% of T patients, but linearized rates showed little difference and death from infection was rare. CONCLUSIONS: The N device should be used in "stable" patients with body surface area (BSA) greater than 1.7 m2 and with minimal right heart failure. Unstable patients with biventricular failure should receive a CW if the BSA is greater than 1.7 m2 or a T if they are smaller.

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.