Myocardial preservation.

The principles used to develop techniques for myocardial preservation in cardiac surgery have been successfully applied to the protection of the donor heart in transplant surgery. This article reviews the latest advances in myocardial preservation during cardiac surgery and shows how they have been adopted in current cardiac transplant techniques.

Cardiac transplantation: indications, procurement, operation, and management.

Between July 1982 and April 1984, 22 patients underwent cardiac transplantations at the Texas Heart Institute with a cumulative follow-up of 188 patient-months (mean of 8.6 months and a range of 0.5 to 21). The actuarial survival rate at 20 months was 72%. Strict selection criteria for potential recipients and donors, optimal perioperative management, which includes endomyocardial biopsy, and most important the introduction of cyclosporine are the major factors that led to these increasing survival rates. The high incidence of cyclosporine-related complications, especially hypertension and myocardial fibrosis, will require long-term evaluation to adequately assess the therapeutic effectiveness of this new immunosuppressive agent.

Laser-assisted microvascular anastomoses: angiographic and anatomopathologic studies on growing microvascular anastomoses: preliminary report.

A low-powered carbon dioxide laser was used to perform end-to-end anastomoses of growing femoral arteries (mean diameter 1.6 mm) in miniature swine. Five microvascular conventional anastomoses were performed with 10-0 monofilament interrupted sutures. Nine laser-assisted vascular anastomoses were performed. The mean duration of each anastomosis was 30 +/- 3 minutes for the conventional anastomosis and 20 +/- 2 minutes for the laser-assisted vascular anastomosis (p less than 0.05). All anastomoses were patent at the completion of the procedure. Each laser-assisted anastomosis required an average of eight laser pulses of 2 to 4 seconds. After 13 weeks the external diameters of the conventional anastomoses were 1.8 mm (+15%), while the laser-assisted anastomoses averaged 3.0 mm (+81%) (p less than 0.05). All nine laser-assisted anastomoses were patent, functional, and free of stenosis compared with one out of five conventional anastomoses. Histologically the laser induced minimal or no fibrosis, allowing normal physiologic healing and growth patterns. Electron microscopy confirmed that the integrity of the arterial layers had been restored. These findings suggest that a low-energy carbon dioxide laser has potential clinical application for anastomosis of small growing vessels.

Cardiac transplantation at the Texas Heart Institute: comparative analysis of two groups of patients (1968-1969 and 1982-1983).

Two groups of heart transplant recipients were studied. Patients in Group 1 underwent heart transplantation from May, 1968, to November, 1969. They were compared with Group 2, a series begun in July, 1982, when the current cardiac transplantation program was renewed at the Texas Heart Institute, and terminated in December, 1983. Patient selection, management, and results were compared. With a cumulative follow-up of 64 patient-months (Group 1) versus 93 patient-months (Group 2), the actuarial 18-month survival was 0 in Group 1 versus 70% in Group 2. Nine of the 18 patients in Group 1 died of rejection versus 4 of the 18 patients in Group 2. There were 6 infection-related deaths in Group 1 and none in Group 2. Using linearized rates based on 100 patient-months, the incidences of rejection and infection were, respectively, 23 versus 10.7 (p less than 0.05) and 64 versus 34 (p less than 0.05) between Groups 1 and 2. Incidence, pattern, and severity of these major complications have been reduced significantly. Over the last decade, there have been improvements in the selection of potential candidates, better management of donors, improved graft preservation, and the introduction of more selective immunosuppression.

Surgical treatment of mitral systolic click syndrome: results in 37 patients.

From 1974 to 1983, 37 symptomatic patients with mitral systolic click (Barlow's syndrome) underwent mitral valve repair. In 11 patients (30%), the click syndrome was associated with minor mitral regurgitation. Thirty-two patients (86%) had chest pain, 20 had arrhythmia (54%), and 20 had dyspnea as a major complaint. In 5 patients, the arrhythmia was serious, and in 2 of them, it was potentially life threatening. Mitral annuloplasty using a collar prosthesis was performed in 33 patients with posterior leaflet plication in 2, shortening of the chordae in 1, and commissural plication in 2. In 4 patients, commissural plication was performed. One of these patients also required cusp plication and shortening of the chordae, and another required repair of ruptured chordae. There were no operative or late cardiac-related deaths at a mean follow-up of 4.7 years (range, 1 to 10 years). Sixty-two percent of patients with prolapse alone and 91% of those with associated regurgitation were improved by at least one New York Heart Association Functional Class, with 60% of patients obtaining relief of one or more symptoms. In the presence of major symptoms, mitral annuloplasty offers symptomatic relief for some patients with mitral systolic click syndrome without valve incompetence, but it gives substantially better results in patients with mitral regurgitation.

Experimental technique of laser coronary endarterectomy and its immediate effects on atherosclerotic plaques in cadaver hearts.

The immediate effects of carbon dioxide laser radiation were assessed in the normal canine aorta, the human atherosclerotic aorta, and 24 human coronary arteries from nine cadaver hearts. The parameters needed for precise control of laser energy were identified. Penetration of a 1-mm thick arterial wall required a minimum power (5 watts), power density (781 watts cm(2)), and radiant energy (1.5 joules). Use of an optimal pulse duration (30 msec or less) resulted in less thermal injury to the adjacent arterial wall. Laser radiation relieved stenosis and reopened totally occluded vessels in 21 of 24 coronary arteries. Coronary stenoses were not relieved in two heavily calcified arteries, and perforation occurred in another artery. In successfully treated arteries, laser coronary endarterectomy increased the luminal diameter from 25 to 100%.

Epicardial cryoablation of the bundle of His. An experimental study.

An extracardiac, transepicardial approach to the atrioventricular junction, allowing selective cryoablation of the bundle of His, was performed in 10 mongrel dogs. This technique appears to minimize dissection complications, the risk of endocardial damage, and injury to the tricuspid valve, which are reported with endocardial cryoablation. All dogs survived this experiment, and no morbidity was reported. Cryodestruction of the atrioventricular junction is histologically selective and permanent, as was shown at the 3 month follow-up pathological examination.

Infection after cardiac transplantation: treatment and prognosis.

Since July 1982, 18 patients have undergone orthotopic cardiac transplantation at the Texas Heart Institute with steroid and cyclosporine immunosuppression. There have been no deaths from infection despite 15 bacterial, 8 viral, 6 fungal and 1 protozoal infection episodes. With a total follow-up of 90 patient months (mean follow-up, 5.0 months; range 0.1 to 18 months), the incidence of infection is 33 episodes per 100 patient months (1.7 episodes per patient). Only 23 episodes (77%) required drug treatment. Compared to conventional immunosuppressive regimes, cyclosporine treatment is associated with a substantial reduction in the incidence and severity of infection in cardiac allograft recipients.

Evolution of the Texas Heart Institute Distant Organ Procurement Program.

Between August and December 1983, the Texas Heart Institute Transplantation Service performed 10 cardiac transplants. All hearts were removed at outside hospitals and transported to the Heart Institute. Adequate return of cardiac function occurred in all groups after ischemic times of 58.5 minutes for hearts procured within Houston (range, 56-62 minutes) and 152 minutes for those procured in other cities (range, 130-179 minutes). Eight of the transplant patients are alive and well following operation. Distal procurement has more than doubled the number of suitable organs, and offers considerable potential for expansion of the transplant program.

Total disconnection of the right ventricular free wall: surgical treatment of right ventricular tachycardia associated with right ventricular dysplasia.

Arrhythmogenic right ventricular dysplasia is a myopathy that affects the right ventricular free wall (RVFW) and gives rise to recurrent reentrant ventricular tachycardia (VT). Because the entire right ventricle is potentially arrhythmogenic, ablating a single site of VT may not eliminate the arrhythmia. We developed an operation to confine any arrhythmic activity arising from the right ventricle to that chamber: total disconnection of the RVFW from the left ventricle. We performed RVFW disconnection in two patients with refractory VT associated with arrhythmogenic right ventricular dysplasia. At least two sites or origin of morphologically distinct VT were identified in the RVFW in each patient. RVFW disconnection was carried out under normothermic cardiopulmonary bypass. An encircling incision was made along the attachment of the RVFW to the aortoventricular unit and the tricuspid annulus; the right coronary artery and its RVFW branches were left intact. Electrical activity of the two chambers became dissociated, and VT arising from the RVFW was confined to that chamber. Postoperatively, there was no clinical evidence of hemodynamic impairment (follow-up 4 months and 3 months). Left ventricular function was unchanged and right ventricular flow was maintained by atrial contraction and motion of the septum toward the RVFW during left ventricular systole. One patient had incessant right ventricular tachycardia confined to the RVFW for 3 weeks. We conclude that RVFW disconnection is feasible and applicable to patients with refractory VT originating in the diffusely diseased RVFW.

Chronic in vivo evaluations of a long-term, implantable left ventricular assist system.

Total THI/Gould LVAS experience includes 59 pneumatically and electrically-actuated blood pump evaluations (in calves, goats and sheep), including 23 studies with the Gould Model V energy converter. This experience has resulted in greater than 8 cumulative years of actuation, in vivo, including electrically-actuated LVAS durations up to 6 mos.

Surgical treatment of annuloaortic ectasia.

Twenty-two patients with annuloaortic ectasia (an aneurysm of the ascending aorta and aortic valve incompetence) due to cystic medionecrosis underwent surgical repair between 1967 and 1979. Twelve patients had Marfan's syndrome and 4 had a forme fruste. The use of a valved conduit and improved techniques of myocardial protection have reduced the perioperative risks and may improve the survival of these patients. Between July 1, 1967 and June 30, 1978, 12 patients had supracoronary repair of the aneurysm and replacement of the aortic valve (group 1); the mortality was 17% (2 of 12). Between July 1, 1978 and Aug. 31, 1979, 10 patients underwent insertion of a valved conduit with implantation of the coronary arteries (modified Bentall procedure, group 2); the operative mortality was 10%. In five group 1 patients (42%) and two group 2 patients (20%) technical problems resulted in bleeding in the early postoperative period. Evidence of a recurrent aneurysm in the diseased segment of the proximal aorta developed in 2 of the 10 group 1 survivors, at 2 and 4 years after operation, respectively. Use of the modified Bentall procedure and cold potassium cardioplegia reduced operative complications from 58% (7 of 12 in group 1) to 20% (2 of 10 in group 2). Because of the low risk of the current procedure and the high risk associated with its natural history, operative intervention should be considered for asymptomatic patients with annuloaortic ectasia.