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PubMedDate not supplied

Perioperative mechanical circulatory support for transplantation.

Mechanical circulatory assistance has become a necessary supplement to more conventional means of hemodynamic support as a shortage of donor organs and associated increase in waiting time have contributed to an increased incidence of hemodynamic deterioration in potential transplant recipients. This review summarizes the experience with circulatory support before and after transplantation of the Utah Transplantation Affiliated Hospitals (UTAH) Cardiac Transplant Program and draws conclusions on the efficacy of one program's use of mechanical circulatory support. Between March 1985 and October 1990, 401 patients were accepted for first-time heart transplantation by the UTAH program. One hundred and eighty patients (46%) were supported before transplantation with conventional hemodynamic therapies, 72 patients (18%) with oral enoximone, 96 patients (25%) with intravenous inotropes, and 34 patients (9%) with an intraaortic balloon; nine patients (2%) required centrifugal blood pump circulatory support. Not included in these statistics are 10 patients awaiting transplantation as of October 10, 1990. Thirty-eight candidates (10%) died awaiting transplantation, 329 (84%) received transplantation, and 24 (6%) were removed from the transplantation list for other reasons. Ten patients (3%) required mechanical circulatory support after transplantation with 38% of this group surviving 1 year after after transplantation. No single factor, including either hemodynamic support before transplantation or donor heart ischemic time, was found to be predictive of the need for mechanical circulatory support after transplantation. One-year survival rates after transplantation of patients requiring mechanical circulatory support before transplantation (86%) were not significantly different than for all transplant patients (88%). The experience of the UTAH Cardiac Transplant Program shows that with the judicious use of mechanical circulatory support transplant patients with advanced forms of hemodynamic support can have as equal a probability of survival as patients who undergo elective transplantation.

Adult↗
PubMed1988

Effect of preoperative hemodynamic support on survival after cardiac transplantation.

The accessibility and success of cardiac transplantation promotes transplantation for a broad range of recipients, including those requiring intravenous inotropes or mechanical-assist devices. To determine if survival is dependent on preoperative requirements for hemodynamic support, we studied 230 patients who underwent transplant at the Loyola, Stanford, and UTAH programs from December 1, 1984 through November 30, 1986, and who were followed up for 34 months postoperatively. Group 1 (n = 132 of 230, 57%) patients required only oral medical therapy to maintain hemodynamic compensation; Group 2 (n = 69 of 230, 30%) patients were dependent on intravenous inotropic support; and Group 3 (n = 29 of 230, 13%) patients required mechanical assistance. Pretransplant characteristics showed that dilated cardiomyopathy was more common in Group 2 patients, and lower cardiac index and ejection fraction were more prevalent in Group 3 patients as expected. Although survival was lower in Group 3 only at 1 month (Group 1, 98.5%; Group 2, 92.8%; and Group 3, 86.2%; p less than 0.01), the survival advantage in Groups 1 and 2 was lost by 3 months, with 1-year survival rates of 88.6% in Group 1, 81.2% in Group 2, and 82.8% in Group 3. Allograft survival and cause of death were not different among the three groups. Acute rejection occurred at a lower monthly frequency in the first 4 months in Group 3 (Group 1, 0.47 +/- 0.03; Group 2, 0.47 +/- 0.05; and Group 3, 0.29 +/- 0.06; p less than 0.01), whereas infectious complications occurred at similar frequencies.(ABSTRACT TRUNCATED AT 250 WORDS)

Assisted Circulation↗
PubMedDate not supplied

State of the art. Circulatory support.

Beginning in midlife, chronic congestive heart failure (CCHF) is a major health problem in the United States. For patients over 65, the costs incurred in treating CCHF are vast, accounting for the highest hospitalization charges among all DRG's for Medicare patients. Heart transplants are an important but insufficient solution to the problem. Consistent progress is being made in the development of left ventricular assist devices, and, along with preventive and other therapeutic approaches, left ventricular assist devices have the potential for being a significant part of the solution for CCHF.

Aged↗
PubMedDate not supplied

Bioprosthetic valve calcification and pseudoneointimal proliferation in bovine and ovine models.

Both porcine (PX) and bovine pericardial (BP) valves have been used in the implantable Novacor left ventricular assist system (LVAS). Results from 58 chronic LVAS implants of greater than 7 days in calves and adult sheep are presented: the PX valve was used in 41 and the BP in 17. With PX valves, the maximum and mean assist durations were 161 and 54 days, respectively, in the calf and 279 and 129 days, respectively, in the sheep. The maximum and mean durations for BP valves were 93 and 38 days (calf) and 153 and 69 days (sheep). In bovine studies with PX valves, severe obstructive pseudoneointimal (PNI) proliferation in the Dacron inflow conduit was the primary cause for termination; valves exhibited moderate calcification. With BP valves, both PNI proliferation and severe valve calcification contributed to a declining pump output, leading to termination. In contrast to the bovine experience, PNI proliferation was not observed in ovine implants. BP valves still became calcified, as evidenced by a progressive decline in pump output (from about twelve weeks) and confirmed at termination. Valve calcification was minimal with the PX valves, even at 236 days. These results favor the adult ovine animal model for extended implants.

Animals↗
PubMed1988

[Clinical use of the artificial heart, indications and results].

Clinical experience with the artificial heart now comprises 520 cases. 390 patients had to be supported mechanically when they could not be weaned off cardiopulmonary bypass. 177 (45%) subsequently had their assist devices removed and 100 (25.4%) were discharged. Good functional results were achieved, since 30 of 36 long-term survivors are in NYHA class I or II. 140 underwent two-stage cardiac transplantation. Of 63 patients implanted with a ventricular assist device (VAD) 71% were transplanted and 51% survived. A total artificial heart (TAH) was used in 77 cases, 81% were transplanted and 47% survived. Five patients received TAH implantations as a permanent replacement of the failing heart. Though the clinical courses were complicated by strokes and infections and the patients were tethered to bulky drive units, it was proven that the TAH may sustain human life for up to 622 days, much longer than so far achieved in animal experiments. Improvements of the atrial connectors and valve holding components and of the biocompatibility of the blood contacting surfaces should overcome the complication of thromboembolism. Fully implantable devices which are currently being developed will avoid the problem of drive-line infections and provide fuller mobility to the patient.

Assisted Circulation↗
PubMed1985

Temporary left heart bypass and total artificial replacement.

Research into left heart assistance was initiated in Berlin in the 1960s with a small implantable pump between the left atrium and the aorta with an extracorporeal driving unit. From thereon, different blood pumps were developed from different materials, the latest types being made out of polyurethanes. Similar designs are used for the total artificial heart. Longest function times exceed 200 days, partly with problems similar to those of the artificial heart. Total artificial heart research began in 1962. The present system consists of 2 polyurethane blood pumps divided by 3 membranes into blood and energy transmission chambers. The longest testing function time is now more than 2 years. The outside driving units of different sizes and designs are connected with tubes and special quick connectors to the right and left atrium, aorta and pulmonary artery. Air capsulae for pressure measurements are incorporated. In addition to all the interesting hemodynamic parameters a great deal of analysis on hematology, biochemistry and metabolic function has been done. The longest survival time in animals is over 200 days. Complications and problems are mostly due to the material, in which small lesions, cracks or slight flaws in fabrication or biodegradation are the starting point for thrombosis and later on calcification. The number of patients who should be given temporary cardiac assistance or total replacement is discussed.

Animals↗