Recent animal studies suggest that cardiac hypertrophy compromises the coronary circulation. Although flow per gram of ventricle in most animal models of hypertrophy is normal, coronary vasodilator responses to pharmacological or physiological stimuli are mildly impaired. Studies of regional perfusion indicate that the limitation of coronary vasodilator capacity in hypertrophied ventricles primarily affects the endocardium. In contrast to studies in animals, measurements of coronary reactive hyperemia in man suggest that coronary dilator responses are profoundly depressed in patients with severe left ventricular hypertrophy secondary to aortic stenosis. These studies in man demonstrate that alterations in the coronary circulation secondary to cardiac hypertrophy are of sufficient magnitude to contribute to the development of angina and heart failure (secondary to endocardial fibrosis) in patients with aortic stenosis.

Animals↗

PubMedDate not supplied

Medtronic Freestyle aortic root bioprosthesis: Implant techniques.

BACKGROUND: The Medtronic Freestyle aortic root bioprosthesis is a complete porcine aortic root to allow implantation (1) as a subcoronary valve replacement by removing graft sinus aorta, (2) as a cylinder with the sinotubular junction intact within the aorta (root inclusion), or (3) as a complete aortic root replacement. The choice among the three implant techniques depends on surgeon preference or upon the pathology encountered. The advantages and differences among the three implant techniques are examined. METHODS: The Medtronic Freestyle bioprosthesis was implanted in 1163 patients in a Food and Drug administration (FDA) clinical trial between August 1992 and October 1997. There were 21 centers in the international trial using a single data repository. Clinical data was collected prior to and at operation, at 3 to 6 months and annually. The data were compiled and statistical analysis performed at the data center. RESULTS: Patients having subcoronary valve implants were older (80% > 65 years) and aortic occlusion time was about 20 minutes less than the other methods. Patients having aortic root replacement presented with more aortic valve insufficiency (20%). Pathology of the aortic root and ascending aorta requiring repair was 26%, and larger (27 mm) valves were used in 40% of patients. Risk of operation was lowest (5.0%) with subcoronary valve implants and highest (11.7%) with root replacement technique. Thromboembolism was higher, early and late, with root inclusion (3.0, 3.9%/patient per year) and root replacement (3.2, 3.0%/patient per year) than for subcoronary implants (1.8, 1.6%/patient per year). There were more patients taking warfarin at the 4-year point with root inclusion (20%) or root replacement techniques (24%) than among patients having subcoronary implants (14%). Explants of the valve occurred in 2% of patients, none of whom had aortic root replacement. CONCLUSIONS: The Medtronic Freestyle bioprosthesis is an effective and versatile device for replacement of the aortic valve. It offers implant techniques that can treat the aortic root pathology encountered at surgery and allows the operation to proceed according to surgeon preference.

Aged↗

PubMedDate not supplied

Cardiac valve operations using a partial sternotomy (lower half) technique.

BACKGROUND AND AIM: Operations on cardiac valves are being performed more frequently through smaller incisions than traditional midline sternotomy. A variety of alternate incisions have been used, but most of the interest appears to focus on partial sternotomy. The purpose of the study was to review results using a partial lower sternotomy for cardiac valve operations. METHODS: A standard partial lower one-half or two-thirds sternotomy was used for cardiac valve operations in 112 patients. The sternum was divided transversely in the third or second intercostal space and vertically from that point through the xyphoid process. Standard instruments and retraction devices were used. This incision provided adequate exposure for even complex operations to be performed. Small cannulae were placed into the aorta and heart through the primary incision for cardiopulmonary bypass. Vacuum-assisted venous drainage was used. RESULTS: Seventy-four single valve operations were performed. There were 35 double valve and 5 triple valve operations (35.4%) performed. Operative mortality (5.3%) and major complication rates were comparable to full the sternotomy approach. CONCLUSIONS: Partial sternotomy (lower half) provides a smaller incision through which virtually all cardiac valve operations may be performed. Results achieved with this approach are similar to those associated with full sternotomy. The smaller incision is appreciated by patients.

Adolescent↗

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↗

PubMedDate not supplied

Vascular rejection and its relationship to allograft coronary artery disease.

We have prospectively monitored 268 patients by our previously described method of routine immunofluorescence of endomyocardial biopsy specimens. We have classified these patients according to their rejection pattern: cellular, vascular, and mixed. The criteria for these designations have been previously described. In this study we retrospectively reviewed coronary angiograms of these patients to assess the presence and time-course of developing allograft coronary artery disease. All available explanted hearts and postmortem hearts were also assessed by light microscopic examination for acute coronary vasculitis and allograft coronary artery disease and by immunofluorescent microscopy for vascular immune complex deposition in a manner identical to immunofluorescent microscopic examination of endomyocardial biopsy specimens. Patients were also monitored for sensitization to immunoprophylactically administered murine monoclonal CD3 antibody (OKT3) and those demonstrated to be sensitized were separately analyzed. Clinical features and treatment of patients were retrospectively reviewed. We found that 141 patients could be classified as having cellular rejection, 76 as having vascular rejection, and 52 as having a mixed rejection pattern. The allograft survival in vascular rejection patients was significantly worse than in allografts of patients with cellular or mixed rejection, confirming our earlier results. Most importantly, we found a significant difference in the time to the development of allograft coronary artery disease based on the rejection pattern. This difference existed whether or not patients sensitized to OKT3 were excluded from evaluation. Patients with mixed rejection had an intermediate time to the development of allograft coronary artery disease between that of patients with cellular and vascular rejection.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Disease↗

PubMedDate not supplied

Fibrinoid necrosis of a temporal artery complicating the treatment of refractory cardiac allograft rejection with murine monoclonal CD3 antibody (OKT3).

The murine monoclonal CD3 antibody (OKT3) is effective in the treatment of refractory renal and cardiac allograft rejection and holds promise for improving rejection prophylaxis in heart transplantation. Although the administration of OKT3 is associated with many side effects, arteritis has not been previously reported. We report the development of acute necrotizing temporal arteritis associated with the deposition of mouse immunoglobulin G in a heart transplant recipient receiving OKT3 treatment of refractory rejection.

Antibodies, Monoclonal↗

PubMedDate not supplied

Hypercholesterolemia after heart transplantation: amelioration by corticosteroid-free maintenance immunosuppression.

Most heart transplant recipients develop hypercholesterolemia, the cause of which is poorly understood. To test the hypothesis that corticosteroids contribute to the hypercholesterolemia, we reviewed 117 consecutive heart transplant recipients who survived more than 4 months, of whom 51 (44%) required and 66 (56%) did not require maintenance corticosteroids, chronic immunosuppression maintained with cyclosporine and azathioprine only. Fasting serum cholesterol levels were measured every 3 months and were found to be 21% to 26% lower during the first 18 months after heart transplantation in the group that did not require chronic corticosteroid administration (p less than 0.001). Beginning 3 months after transplantation, average serum cholesterol levels ranged from 199 +/- 8 mg/dl to 211 +/- 9 mg/dl in the corticosteroid-free group compared with 262 +/- 8 mg/dl to 272 +/- 8 mg/dl in patients requiring corticosteroid maintenance immunosuppression. Because serum cyclosporine levels did not differ between the groups, a contribution by cyclosporine to posttransplant hypercholesterolemia could not be substantiated. Although the hypercholesterolemia that occurs after heart transplantation is undoubtedly multifactorial, corticosteroid administration contributes importantly to its development.

Adrenal Cortex Hormones↗