Transaortic repair of mitral regurgitation.

BACKGROUND: In the operative management of mitral regurgitation (MR) associated with aortic valve disease, a transaortic approach combining the bowtie mitral valve repair with replacement of the aortic valve appears to offer a less invasive and technically simple, expeditious alternative to conventional left atriotomy and Carpentier style repair. METHODS: Between February 1997 and December 1999, four patients underwent a bowtie repair of the mitral valve via the aortic root with concomitant aortic valve replacement. The diagnosis of MR was established and followed postoperatively by echocardiogram. The operative technique involved a transaortic annular approach to the mitral valve with a single edge-to-edge suture approximating the prolapsing posterior mitral leaflet to a normal segment of the anterior leaflet. RESULTS: There were no operative mortalities. Mean cross-clamp time for both valve procedures was 104 +/- 24 min and cardiopulmonary bypass was 155 +/- 31. Mean postoperative cardiac output was 5 +/- 1 L/min. Semiquantitative estimation of mitral regurgitation by doppler improved from a mean of 3.2 +/- 0.5 preoperatively to a mean of 0.25 +/- 0.5 (p = 0.0052) postoperatively, while ejection fraction (EF) remained stable (48 +/- 9% preoperatively and 49 +/- 9% prior to discharge). One patient with rheumatic mitral pathology had a mild increased mitral gradient which did not resolve with takedown of the bowtie repair. Mitral stenosis was not evident in any of the other patients. CONCLUSIONS: Our initial experience with the combined transaortic bowtie repair and aortic valve replacement has demonstrated that this approach is very quick, feasible, effective, and technically simple with gratifying midterm results.

Endarterectomy for preventing stroke in symptomatic and asymptomatic carotid stenosis. Review of clinical trials and recommendations for surgical therapy.

BACKGROUND: Multicenter, randomized trials have demonstrated advantages for surgery over medical therapy in both symptomatic and asymptomatic carotid stenosis of greater than 70%. Controversial interpretations of these trials are debated between medical and surgical camps. The goal of this review is to summarize the current state of knowledge in carotid stenosis and the role of surgery and several advances in operative management. METHODS: Summaries of seven major controlled trials of carotid endarterectomy versus medical therapy are presented along with supportive data from over 90 related publications. Criticisms, deficiencies as well as strengths are offered. RESULTS: All studies in which trial design, clinical variables, case selection, complication definition, and patient follow-up were well conceived and performed showed statistically significant advantages for surgical therapy within a remarkable short interval of follow-up (less than 3 years). Carotid endarterectomy demonstrated a two to four fold reduction in the late incidence of stroke when compared to optimum medical management (risk factor reduction and initiation of antiplatelet therapy). Reduction in stroke risk over time remains stable in surgically treated patients whereas medically treated patients clearly show progression of stenosis and evolution of new neurologic events with time. Several studies indicate that diabetes is a risk factor for stroke with medical therapy that is eliminated by surgical therapy. Advantages were more clearly demonstrated when symptomatic patients (TIAs, stroke, or amaurosis) were studied, but asymptomatic patients received significant benefit as well. The degree of benefit measured was in direct balance to the perioperative risk. Perioperative stroke and death rates must be low (less than 3% combined for asymptomatic patients) in order for statistically significant differences to be detected. However, most centers now can perform carotid endarterectomy within these outcome parameters. CONCLUSIONS: Randomized trials support the safety and efficacy of carotid endarterectomy for stenosis greater than 70% (with or without symptoms). Advantages of surgery over medical therapy were found in less than three years and there is ample evidence to suggest that the differences between these groups would have been even more pronounced had longer follow-up been obtained. Thus for patients who face many years of risk after diagnosis of a carotid lesion, early surgery is the most important and effective intervention for preventing stroke. The results of these trials raised initial concern over increasing health care expenditures from rising surgical case volumes. However, studies of cost effectiveness confirmed that surgery saves health care dollars when compared to the long term care of stroke victims.

Coronary grafting using a temporary intraluminal shunt instead of heart-lung bypass.

The application of a temporary intraluminal shunt is presented as a technique to prevent ischemia when coronary grafting is performed without cardiopulmonary bypass. This simple maneuver expands the indications for coronary grafting without cardiopulmonary bypass.

Platelet and fibrin metabolism in recipients of the Jarvik 7 total artificial heart.

Recipients of the total artificial heart are at risk for device-related thrombus formation and thromboembolism. Platelet and fibrin metabolism was studied in four patients who received the Jarvik 7 total artificial heart as a bridge to transplantation and in eight patients after orthotopic heart transplantation. Platelet activation was assessed by measurement of plasma levels of beta-thromboglobulin, fibrin formation by fibrinopeptide A, and fibrinolysis by cross-linked fibrin degradation products. These markers were increased after surgery with only minimal differences between the two patient groups for the first 3 days. In comparison to heart transplant patients, these markers remained elevated in artificial heart recipients despite anticoagulation therapy. beta-Thromboglobulin levels did not decrease in two artificial heart recipients who received aspirin. Markers of platelet and fibrin activity were greatly increased in one artificial heart recipient who had impaired inflow into the device, was not anticoagulated because of bleeding, and had extensive device-related thrombus on explantation. Plasma markers of platelet and fibrin metabolism provide biochemical assessment of in vivo thrombus activity in artificial heart recipients. Monitoring these markers may provide an additional means of guiding anticoagulation therapy in patients with artificial hearts and assessing interventions designed to reduce device-related thrombus formation.

Infectious complications in four long-term recipients of the Jarvik-7 artificial heart.

This article describes the infectious complications that occurred among four of the longest-term recipients of the Jarvik-7 artificial heart. Infection arising from the drive lines, with spread to the mediastinal periprosthetic space, was the major limiting factor in long-term use of the device in these patients. Periprosthetic infections were due to coagulase-negative staphylococci, Staphylococcus aureus, Pseudomonas aeruginosa, and other Pseudomonas species. Other infectious complications incurred by some of the patients included pneumonia, empyema, urinary tract infection, and intravascular line sepsis with Candida. Intensive antimicrobial therapy for prolonged periods seemed to suppress but not to eradicate infection and was accompanied by the appearance of multiresistant bacterial strains. Complications of antimicrobial therapy included diarrhea secondary to overgrowth with Clostridium difficile in two patients. Use of the current device for more than 30 days should be considered extraordinary and should be reserved for patients for whom no other form of life support is available.

Technical aspects of total artificial heart implantation for temporary applications.

Temporary use of the Jarvik-7 artificial heart in critically ill patients awaiting transplantation has prevented death in greater than 60% of attempts. Success is very dependent on meticulous surgical technique. Failures in the operating room cascade into enlarging problems postoperatively. Appropriately selected patients implanted without bleeding or fit problems recover quickly and are suitable candidates for transplantation within a few days. Even acute renal failure or pulmonary insufficiency from end-stage cardiac disease rapidly reverses upon restoration of normal hemodynamics. Anticoagulation is mandatory to prevent thromboembolism and continuous heparin plus oral dipyridamole is the most successful regimen to date. Primary intraoperative security of all suture lines or potential bleeding foci is thus essential. Bleeding has been associated with tamponade, pulmonary complications, and transfusion stimulated anti-HLA antibodies which can prevent subsequent transplantation. The length and suturing technique of the aortic conduit are critical. Compression of the mediastinal structures by the device can impede systemic or pulmonary venous return, with disastrous results. Displacement of the blood pumps away from the midline, usually into the pleural space, allows for more room when closing the sternum. The 100 cc blood pump fits best in patients greater than 85 kg, while the 70 cc model can be implanted in patients as small as 50-60 kg.

Selection of patients for cardiac transplantation.

Selection of potential cardiac recipients is not a simple process. Identification of patients who are declining from end-stage cardiac disease and may be expected to die within 12 months or less and deciding which of a number of cardiac invalids are reasonable candidates for cardiac transplantation involves prognostication as well as a working knowledge of the expected benefits and survival rates in cardiac transplantation. Screening by means of the currently accepted contraindications for cardiac transplantation is somewhat more difficult in 1986 than it was 10 years ago when these contraindications were changing less rapidly. However, for optimal use of the limited supply of donor organs and maintenance of reasonable survival rates such screening is absolutely necessary. A second area of restriction that is less approachable by the physician is that of financial limitations. It would appear that the working poor and lower middle class may be deprived of the opportunity for cardiac transplantation much as they are deprived of the opportunity for optimal medical care in our society today.

The total artificial heart as a bridge to transplantation. A report of two cases.

In 1985, at the University of Arizona, Tucson, two attempts were made to "bridge" patients from impending death to heart transplantation, using orthotopically positioned total artificial hearts. The first attempt, using an unapproved device on an emergency basis, failed after transplantation because of severe pulmonary edema and Pseudomonas pneumonia and the apparent transmission of a Pseudomonas infection from donor to recipient. The second experience, using a Jarvik-7 device, led to stable support for nine days with one major complication, a reversible neurologic deficit with no associated computed tomographic scan abnormality. This patient survived cardiac transplantation and, after being successfully treated for complications, has made a full recovery and returned to full-time work.

Use of pericardial fat pad flap to prevent bronchopleural fistula.

Use of the pericardial fat pad flap to cover the bronchial stump following pulmonary resection can minimize the occurrence of bronchopleural fistula, a serious complication. The surgical technique as shown is safe and easily accomplished.

Cardiac transplantation in patients over 50 years of age.

Sixty-two patients underwent cardiac transplantation at the University of Arizona from March 1979 to March 1985. Thirteen patients (11 men and 2 women) were over 50 years of age at the time of transplantation and 49 were under the age of 50. The mean age (+/- SEM) of the patients over 50 was 53 +/- 1 years. Eight of these patients were treated with conventional immunosuppressive therapy (azathioprine, prednisone and rabbit antithymocyte globulin) and five, beginning in January 1983, were treated with cyclosporine, prednisone and rabbit antithymocyte globulin. Early mortality (0 to 90 days) was 16% in the group over 50 versus 18% for those under 50. The late mortality (greater than 90 days) was 36 and 33%, respectively. In both groups, rejection and infection were the principal causes of death. The incidence of infection was 1.9 +/- 0.5 episodes per patient in those patients over 50 and 1.9 +/- 0.4 in those under 50. The incidence of rejection was 1.3 episodes per patient-year in patients over 50 and 1.7 episodes per patient-year in those under 50. Actuarial survival at 1 year was 72 +/- 14% in the group over 50 and 66 +/- 7% in the group under 50 years of age. These data indicate that the results of cardiac transplantation for patients over 50 do not differ significantly from those for patients under 50. Therefore, it is concluded that a rigidly defined age criterion for cardiac transplant recipients is not acceptable. Each potential recipient must be evaluated in terms of individual risk and benefit from the procedure.

Cardiac transplant patient at one year. Cyclosporine vs conventional immunosuppression.

From March 1, 1979 thru September 30, 1984 we performed 56 cardiac transplants (Tx). The first 32 patients received conventional immunosuppression therapy consisting of azathioprine/prednisone (I/P), while the subsequent 24 patients received cyclosporine/prednisone (C/P). Twenty-one of 32 I/P patients ages 39 +/- 3 years (SEM), and 16 of 24 eligible C/P patients ages 36 +/- 3 years, survived one year with follow-up through September 30, 1985. The one year post-transplant course of these 37 patients was evaluated by chart review. While donor ages are similar, ischemic time was shorter in the conventionally treated patients. The initial hospital stay for I/P vs C/P was 67 +/- 6 vs 33 +/- 3 days (p less than .05), at a total cost of $49,900 +/- $5,800 vs $53,800 +/- $10,000. During the first year following transplantation, the I/P patients required an additional 34 +/- 7 days of hospitalization, while C/P patients required 16 +/- 10 days. Over the first year, the number of infections and rejections differed at 2.8 +/- 0.6 per I/P patient vs 1.2 +/- 0.3 per C/P patient, and 2.5 +/- 0.4 per patient vs 1.5 +/- 0.3 per patient respectively (p less than .05). Renal function test results were better in the I/P group. Results of cardiac catheterization performed at one year were similar except for cardiac index and stroke volume index, both being higher in the C/P group. Coronary anatomy was considered normal in all. These data indicate that while overall survival is similar, a shortened post-transplant hospital course with fewer necessary hospitalizations, rejection episodes and infection episodes characterizes the first year in survivors receiving C/P immunosuppression. While both groups had multiple hemo-dynamic abnormalities as compared to normal subjects, cardiac index and stroke volume index were improved in the C/P group. Therapy with C/P represents an advance in immunosuppression for cardiac transplantation as compared to I/P; however, decreased renal function and diastolic hypertension were problems in the C/P group.

Thromboembolic complications of the Jarvik-7 total artificial heart: case report.

The Jarvik-7 total artificial heart (TAH) has now been implanted in seven patients, with four (57%) suffering cerebral embolic events. Functional recovery in two patients was impaired by subsequent intracranial hemorrhage from anticoagulant therapy. The findings of a Jarvik-7 TAH explanted following a cerebral embolus are reported here. Thrombotic deposition was seen in the inner crevice formed between the two components of the aortic quick connector. In addition, deposition was seen around all four valves in the crevice formed between the valve ring and the plastic valve housing. On the atrioventricular valves, the deposition in this crevice was most severe on the outflow surface adjacent to the minor flow orifice. On the pulmonic valve, deposition was seen around the entire circumference of both the inflow and the outflow crevices. No thrombi were seen on the diaphragm, the diaphragm-housing junction, or the housing of the left ventricle. Hypercoagulability of the patient's blood gradually developed during implant, reaching a maximum on the evening before the clinical embolus. Increasing resistance to heparin was also demonstrated by in vitro testing.

Surgical positioning of the Jarvik-7 artificial heart.

The Jarvik-7 total artificial heart has been implanted in 18 patients at the time of this writing. Eleven patients received the 100 ml heart, and the remaining seven were treated with the 70 ml device. To date, five patients have been implanted for permanent use with an average survival in excess of 9 months, and the longest survival is more than 1 1/2 years following implantation of the heart. Complications related to positioning were a contributing factor in the death of one patient. Thirteen patients have received the Jarvik-7 heart as a bridge to transplant. Three died before transplant, and the remaining ten have been transplanted. To date, all are alive, several are home and in excellent condition, and several are still hospitalized but are expected to be released shortly. Three patients have experienced serious complications after transplantation. One patient rejected her heart transplant, was reimplanted with the artificial heart, and now has been sustained for more than 3 months. At this time she is in good condition awaiting a second donor. Selection of the appropriate size Jarvik-7 artificial heart for the individual patient can best be made based on measurements of thoracic dimensions obtained from a computed tomography scan and calculation of body surface area. The appropriate medial or lateral positioning can be determined and decisions concerning the lengths of the grafts and cuffs, excision or nonexcision of the left pericardium, and air drive line position can be made. The Jarvik-7 heart can be successfully used in patients from 50 kg. However, at the lower size limit in patients from approximately 50 to 65 kg, the risk of fit complications is the greatest and availability of an even smaller model heart would be desirable.

Indexes of hemolysis in human recipients of the Jarvik-7 total artificial heart: a cooperative report of fifteen patients.

The degree of red cell destruction in human recipients of the total artificial heart has not previously been described. Fifteen patients implanted with a Jarvik-7 total artificial heart for either temporary or permanent heart replacement were reviewed. Clinically significant elevations of plasma free hemoglobin and serum lactate dehydrogenase were demonstrated in patients receiving the standard (100 ml) Jarvik-7 containing Medtronic-Hall valves and powered by pulses of compressed air delivered at a dP/dT of 6000 mm Hg/sec to 8000 mm Hg/sec. Reduction of the dP/dT by drive unit modification greatly reduced the plasma free hemoglobin and lactate dehydrogenase in subsequent patients. Introduction of the smaller (70 ml) total artificial heart was not associated with greater hemolysis once dP/dT had been reduced. With the current driver delivering systolic pulses at less than 4500 mm Hg/sec, both size hearts are free of clinically relevant hemolysis. In addition, it appears that attempts to eliminate hemolysis completely by lowering heart rates, cardiac outputs, or driving pressures are potentially dangerous. The eventual development of embolic cerebrovascular accidents is associated statistically with heart rates below 80 beats/min. These data reassure implanting physicians that the updated Jarvik-7 total artificial heart system does not induce worrisome hemolysis. In addition, this study has uncovered a link between eventual cerebrovascular accident and low heart rate, implying that purposeful application of heart rates around 100 beats/min may provide a significant margin of protection against cerebrovascular accident during implantation.