Implications of preoperative administration of aspirin in patients undergoing coronary artery bypass grafting. Department of Veterans Affairs Cooperative Study on Antiplatelet Therapy.

The perioperative consequences of preoperative aspirin administration were assessed in a large prospective cooperative study of 772 patients undergoing coronary artery bypass grafting. The 772 patients were randomized to receive either aspirin (325 mg once a day), aspirin (325 mg three times a day), aspirin plus dipyridamole (325 and 75 mg together three times a day) (aspirin group), sulfinpyrazone (267 mg three times a day) or placebo (nonaspirin group). The therapy, except in the aspirin group, was started 48 h before the operation. In all aspirin subgroups, one 325 mg aspirin dose was given 12 h before surgery and maintained thereafter according to the assigned regimen. Patients in the aspirin group had significantly more postoperative bleeding and received more packed blood cells and blood products than did patients in the nonaspirin group. Although total operative duration and cardiopulmonary bypass duration were not different, the interval between completion of cardiopulmonary bypass and wound closure was significantly longer (p = 0.035) in the aspirin group. Thirty-one (6.6%) of 471 patients in the aspirin group and 5 (1.7%) of 301 patients in the nonaspirin group also required reoperation for control of postoperative bleeding (p = 0.002). The site of bleeding found at reoperation was not different between the two groups. There was no difference in operative mortality rates, incidence of other bleeding complications or occurrence of other post-operative complications between the two groups. Thus, antiplatelet regimens involving preoperative initiation of aspirin therapy, which has been shown to improve graft patency, increase the risk of abnormal postoperative bleeding and the need for reoperation.(ABSTRACT TRUNCATED AT 250 WORDS)

Outcomes 15 years after valve replacement with a mechanical versus a bioprosthetic valve: final report of the Veterans Affairs randomized trial.

OBJECTIVES: The goal of this study was to compare long-term survival and valve-related complications between bioprosthetic and mechanical heart valves. BACKGROUND: Different heart valves may have different patient outcomes. METHODS: Five hundred seventy-five patients undergoing single aortic valve replacement (AVR) or mitral valve replacement (MVR) at 13 VA medical centers were randomized to receive a bioprosthetic or mechanical valve. RESULTS: By survival analysis at 15 years, all-cause mortality after AVR was lower with the mechanical valve versus bioprosthesis (66% vs. 79%, p = 0.02) but not after MVR. Primary valve failure occurred mainly in patients <65 years of age (bioprosthesis vs. mechanical, 26% vs. 0%, p < 0.001 for AVR and 44% vs. 4%, p = 0.0001 for MVR), and in patients > or =65 years after AVR, primary valve failure in bioprosthesis versus mechanical valve was 9 +/- 6% versus 0%, p = 0.16. Reoperation was significantly higher for bioprosthetic AVR (p = 0.004). Bleeding occurred more frequently in patients with mechanical valve. There were no statistically significant differences for other complications, including thromboembolism and all valve-related complications between the two randomized groups. CONCLUSIONS: At 15 years, patients undergoing AVR had a better survival with a mechanical valve than with a bioprosthetic valve, largely because primary valve failure was virtually absent with mechanical valve. Primary valve failure was greater with bioprosthesis, both for AVR and MVR, and occurred at a much higher rate in those aged <65 years; in those aged > or =65 years, primary valve failure after AVR was not significantly different between bioprosthesis and mechanical valve. Reoperation was more common for AVR with bioprosthesis. Thromboembolism rates were similar in the two valve prostheses, but bleeding was more common with a mechanical valve.

Six month postoperative hemodynamics of the Hancock heterograft and the Björk-Shiley prosthesis: results of a Veterans Administration cooperative prospective randomized trial.

In a Veterans Administration Cooperative Study involving 13 medical centers, 575 patients undergoing single valve replacement were prospectively randomized to receive either the standard Björk-Shiley prosthesis or the Hancock porcine heterograft (with a modified orifice for sizes 23 and smaller). The hemodynamic data in the 268 patients who underwent cardiac catheterization an average of 6 months (range 3 to 12) postoperatively are reported. Statistical analyses were performed on valve sizes 23, 25 and 27 in the aortic position, and 29, 31 and 33 in the mitral position. A wide variation was observed in mean pressure gradient and calculated orifice area in both valve types within all sizes in both the aortic and the mitral positions. In the aortic position, the Björk-Shiley prosthesis tended to have a lower pressure gradient and larger calculated orifice area than the Hancock heterograft, but the differences in gradient between the two valve types were significant only in the larger-sized valves. The difference in calculated area between the two valve types was not significant within each valve size. In the mitral position, there were no differences in gradient and calculated orifice area between the two types of prostheses. The postoperative cardiac index, regurgitant volume, pulmonary artery systolic and mean pressures, left ventricular end-diastolic pressure, left ventricular ejection fraction and left ventricular end-diastolic volume index did not differ in patients receiving the Björk-Shiley prosthesis from values in patients receiving the Hancock heterograft. Hence, the overall hemodynamic performance of both types of valves is remarkably similar. The choice between these two prostheses should, therefore, be governed not by the hemodynamic performance, but by other factors such as valve durability, risk of anticoagulation and incidence of valve-related complications.

Left atrial dimension and risk of systemic embolism in patients with a prosthetic heart valve. Department of Veterans Affairs Cooperative Study on Valvular Heart Disease.

The relation between left atrial dimension measured by M-mode echocardiography and systemic embolization after valve replacement was examined prospectively among 397 patients with a prosthetic valve enrolled in the Department of Veterans Affairs Cooperative Study on Valvular Heart Disease. Baseline characteristics including several measures of left atrial enlargement were compared for 31 patients who developed systemic embolism and 366 who did not develop embolism during a 5 year follow-up period. Variables that were significantly related to left atrial dimension or systemic embolization in univariate analyses were included with several others in a multiple logistic regression model. The incidence rate of systemic embolism was more than three times higher after mitral valve replacement than after aortic valve replacement (4.4 and 1.3 per 100 patient-years, respectively); this difference persisted after adjustment for other factors. Univariate analysis indicated a threefold higher incidence of systemic embolism in patients with a left atrial dimension greater than or equal to 4 cm compared with that in patients with a dimension less than 4 cm (3 versus 1 per 100 patient-years, respectively). However, when the effect of valve location (mitral versus aortic) was taken into account using either univariate or multivariate techniques, left atrial dimension was found not to be associated with systemic embolism. In multivariate analysis, atrial fibrillation, age, ejection fraction and location of the prosthetic valve were significantly associated with embolism. Results of this multicenter study suggest that left atrial dimension is not independently related to the development of systemic embolism in patients undergoing valve replacement.

Comparison of outcome after valve replacement with a bioprosthesis versus a mechanical prosthesis: initial 5 year results of a randomized trial.

The Veterans Administration Cooperative Study on Valvular Heart Disease was organized to compare survival and incidence of valve-related complications between patients receiving a bioprosthesis (the Hancock porcine heterograft) and a mechanical prosthesis (the Björk-Shiley spherical disc valve). Five hundred seventy-five patients undergoing single aortic or mitral valve replacement were randomized at surgery to one of the two valve types. At an average follow-up of 5 years (range 3 to 8) there are no statistically significant differences in survival between patients with the two valve types in the aortic valve replacement group. There is a statistically nonsignificant trend toward improved survival in patients undergoing mitral valve replacement with a bioprosthesis compared with a mechanical prosthesis (5 year survival probability was 0.70 +/- 0.05 and 0.58 +/- 0.06, respectively). Fatal and nonfatal valve-related complications occurred significantly less frequently in patients with a bioprosthesis compared with a mechanical prosthesis for both mitral and aortic valve replacement. Five year complication-free probability was 0.67 +/- 0.05 and 0.45 +/- 0.06, respectively, for patients with mitral valve replacement and 0.63 +/- 0.04 and 0.53 +/- 0.04, respectively, for those with aortic valve replacement. The difference in overall complication rates was largely due to the increased number of clinically significant but nonfatal bleeding episodes in patients receiving a mechanical prosthesis. Adjustment for differences in baseline characteristics between patients receiving a mitral mechanical prosthesis and a mitral bioprosthesis reduced the statistical significance of the difference in both mortality and complications.

Inadequacy of the Gorlin formula for predicting prosthetic valve area.

A total of 135 patients with normally functioning prosthetic aortic valves who were catheterized 6 months after placement of Hancock, modified Hancock or Bjork-Shiley prostheses were studied to determine the magnitude of error in Gorlin formula estimates of prosthetic aortic valve area. All patients were male, selected from 13 participating hospitals and routinely followed after valve replacement for 5 years. Hemodynamically determined Gorlin valve areas were compared with independently verified actual valve areas. Actual Hancock areas were measured from videotapes of valves exercised in a pulse duplicator flow model. Actual Bjork-Shiley areas were calculated directly from the valves' inner ring radius. Gorlin valve areas correlated poorly with actual valve areas (r = 0.39). The mean Gorlin formula error was 0.36 cm2 (standard deviation = 0.32). Gorlin areas overestimated actual areas by greater than 0.25 cm2 in 43 patients (32%) and underestimated actual areas by greater than 0.25 cm2 in 29 (21%). It was concluded that the Gorlin formula inaccurately predicts prosthetic valve area in the aortic position. Overreliance on this formula in assessing aortic stenosis could lead to errant clinical decisions.

Mild renal failure is associated with adverse outcome after cardiac valve surgery.

The present study was performed to ascertain whether the presence of mild renal failure (defined as a serum creatinine concentration of 1. 5 to 3.0 mg/dL) is an independent risk factor for adverse outcome after cardiac valve surgery. An extensive set of preoperative and postoperative data was collected in 834 prospectively evaluated patients undergoing cardiac valve surgery at 14 Veterans Affairs Medical Centers. Univariate and multivariable analyses were performed to determine whether an independent association of mild renal dysfunction with adverse outcomes was present. Patients with mild renal failure had significantly greater 30-day mortality rates (P = 0.001; 16% versus 6%) and frequency of postoperative bleeding (P = 0.023; 16% versus 8%), respiratory complications (P = 0.02, 29% versus 16%), and cardiac complications (P = 0.002; 18% versus 7%) than patients with normal renal function (serum creatinine <1.5 mg/dL) when controlling for multiple other variables. The presence of a serum creatinine concentration of 1.5 to 3.0 mg/dL is significantly and independently associated with adverse outcomes after cardiac valve surgery.

Extrathoracic bypass for stenosis of innominate artery.

Stenosis of the innominate artery usually occurs in older patients in whom the risks of conventional, corrective procedures such as transthoracic endarterectomy or aorto-innominate arterial bypass grafting are quite high. An axillo-axillary bypass procedure was performed in a high-risk patient with innominate arterial stenosis who had repeated episodes of transient cerebral ischemia due to decreased blood flow through the right carotid artery and reversal of blood flow through the right vertebral artery. Postoperatively, he has had dramatic improvement in his symptoms. Because of its simplicity, avoidance of major thoracotomy, avoidance of temporary occlusion of the carotid artery, and excellent late results, axillo-axillary bypass grafting is being proposed as the procedure of choice for stenosis of the innominate artery.

Iatrogenic coronary artery stenosis following aortic valve replacement.

Until recnetly, coronary arterial perfusion was one of the best methods to protect myocardium during aortic valve replacement. However, the insertion of perfusion cannulas may produce immediate traumatic lesions and late stenosis of the coronary arteries, with grave consequences. Two patients with normal coronary arteries prior to operation developed obstruction of the maximal left main coronary artery following aortic replacement. One of these patients represents the first case of iatrogenic coronary arterial stenosis in which the aortic valve was replaced with a porcine bioprosthesis. Accelerating angina pectoris and ventricular arrhythmias were the presenting clinical manifestations. Aorta-coronary bypass grafting to the left anterior descending and circumflex coronary arteries was successfully performed in one patient, while the other patient died before investigative procedures could be undertaken. Any patient whose aortic valve has been replaced and who develops angina pectoris a few months after operation should be suspected of having developed stenosis of the proximal coronary artery. Coronary angiography should be perfomed promptly. Once the lesion is recognized, the operaiton should be performed posthaste because these lesions are life threatening owing to their proximal location and rapid evolution.

Impact of resident training on postoperative morbidity in patients undergoing single valve replacement. Department of Veterans Affairs Cooperative Study on Valvular Heart Disease.

As one of the requirements of the Department of Veterans Affairs cooperative study on valvular heart disease, operative and postoperative data were prospectively collected in 964 patients undergoing single valve replacement. The procedure was performed either by a resident under the direct supervision of an attending surgeon (49.5%) or by an attending surgeon (50.5%). There was no difference in operative mortality between the two groups of surgeons when adjusted for patient-related and disease-related risk factors. The proportion of patients who had at least one postoperative complication was slightly but not significantly higher in the attending group (35.8% versus 30.4% for aortic valve replacement, 38% versus 28% for mitral valve replacement, and 36% versus 30% for all single valve replacement procedures). As the significance of each complication varies, we weighted each complication to the associated operative mortality to formulate the morbidity score. An expected complication rate for each group was derived from a multivariate logistic model, and the ratio of observed to expected morbidity was calculated to adjust observed morbidity according to the risk of patients. There was no difference in the observed/expected morbidity ratio between the two groups of surgeons. We conclude that currently used teaching techniques and philosophy to educate cardiac surgical residents, which allow them to take progressive responsibility for cardiac surgical procedures, are well justified, and patient care does not suffer when resident training is enhanced.

Management of coarctation with multiple calcified aneurysms of the intercostal arteries in adults.

Coarctation of the aorta in adult patients carries an increased but acceptable surgical risk. Our experience emphasizes the technical advantage of an alternative, simpler surgical procedure, such as bypass grafting between the subclavian artery and descending aorta, when one is faced with a friable aorta and concomitant large aneurysms of the intercostal arteries.

Pulmonary hemorrhage associated with balloon flotation catheters: report of a case and review of the literature.

The development of the flow-directed balloon catheter has greatly facilitated the monitoring of seriously ill patients. As the use of this catheter has increased, so have the reports of complications, the most serious of which is fatal pulmonary hemorrhage. Eleven cases of pulmonary hemorrhage have been described in the literature, and we have reported an additional case. The presenting symptom in 10 patients was hemoptysis, and the course of eight of these patients was rapidly fatal. The most frequent significant finding at autopsy was a laceration of a small peripheral pulmonary artery, usually at a bifurcation. The pathogenesis, prophylaxis, and management of this complication are discussed.

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.

Futility of yearly heart biopsies in patients undergoing heart transplantation.

Three hundred thirty-eight endomyocardial biopsies, performed as part of the routine annual evaluation at 1 or more years after transplantation in 211 patients, were reviewed. In only two instances (0.6%) were the histologic findings suggestive, but not pathognomonic, of acute rejection. Both patients were treated for rejection and are doing well at 4 and 6 years postoperatively. On the basis of the results of this study, we believe that routine yearly heart biopsies in asymptomatic patients are not necessary for long-term care of patients after heart transplantation, and we believe they should be performed only if there is clinical suspicion of rejection or as part of a research protocol.

Obstructive sleep apnea in heart transplant patients. A report of five cases.

Clinically significant obstructive sleep apnea syndrome (OSAS) was diagnosed in five patients who had undergone heart transplantation and they represent 2.5 percent of our transplantation series. To determine if these individuals had unique clinical features that would have suggested the presence of OSAS, we reviewed their case histories. Although four of five patients had symptoms of OSAS prior to transplant, none was suspected of having the diagnosis before their surgery. Excessive daytime sleepiness and loud snoring were noted in all patients, and there were no unusual clinical features that characterized these individuals. Our data indicate that the occurrence of OSAS in heart transplant recipients approximates the prevalence in the general population. Because OSAS may adversely affect cardiac function, we recommend that heart transplantation candidates be screened for a history suggestive of OSAS, and that polysomnography be performed if it is present.

Clinical significance of weight difference between donor and recipient in heart transplantation.

A standard and important criterion for donor acceptance is to match the donor's body weight to within 20% of the recipient's body weight. However, to meet the increasing demand of patients who need heart transplantation, frequently a heart that is below the standard criteria for donation is accepted. Of the 200 consecutive patients who underwent heart transplantation at the University of Arizona, 27 patients received a heart from a smaller donor with a weight difference of more than 30% (range 30% to 46%). The early mortality and late survival of these 27 patients were not different when compared with those of the patients who received transplants from donors with a weight difference of less than 30%. The probability of freedom from rejection and infection and postoperative ejection fraction were also similar between the two groups. Therefore, we believe that the widely accepted donor-recipient weight-match criterion of 20% can be safely extended.

Clinical, hemodynamic, and angiographic predictors of operative mortality in patients undergoing single valve replacement. Veterans Administration Cooperative Study on Valvular Heart Disease.

Preoperative characteristics of 964 patients in the Veterans Administration Cooperative Study on Valvular Heart Disease undergoing single valve replacement were examined to determine predictors of operative mortality. The operative mortality rate was 8.3% in 661 patients having isolated aortic valve disease and 7.5% in 239 patients having isolated mitral valve disease, but 12.5% in 64 patients with multivalve disease undergoing single valve replacement. For the aortic valve replacement subgroup, three-vessel coronary artery disease, left ventricular systolic pressure, prior cardiac operation, body surface area, and cardiac index were related to operative mortality. In the mitral valve replacement group, there was a strong association of operative mortality with advanced age, exertional dizziness, reduced cardiac index, left ventricular contraction grade, ST segment depression on the resting electrocardiogram, and pleural effusion. The risk of operative death for an individual patient undergoing aortic or mitral valve replacement may be estimated with the use of independent risk factors.

Heart-lung transplantation: the initial Arizona experience.

Since November 1985, cardiopulmonary transplantation has been performed at the University of Arizona heart transplant program. Seven patients, five women and two men, have undergone heart-lung transplantation. Five patients had primary pulmonary hypertension, and two patients had Eisenmenger's complex. The mean age was 31 years (range, 17 to 43 years). Average follow-up was 15 months (range, 3 to 34 months), with a total of 115 patient-months. There have been no operative or late deaths. Immunosuppression consisted of rabbit antithymocyte globulin, cyclosporine (Cyclosporin A), azathioprine, methylprednisolone, and prednisone. Our first five patients were aggressively diagnosed and treated for rejection by endomyocardial biopsy, with each patient having one or several treatments for acute rejection. These five patients had one or several episodes of severe infection, particularly cytomegalovirus. In our last two patients we omitted routine heart biopsies. Only those rejection episodes diagnosed by chest x-ray films are considered significant. Our last two patients have not been treated for acute rejection and have had no infections. Presently our immunologic surveillance consists only of careful clinical examination and frequent chest x-ray films. Any changes in the patient's condition are aggressively investigated, searching for infection or rejection. Two patients have been used as domino donors of their native heart.

Rabbit antithymocyte globulin. A 10-year experience in cardiac transplantation.

Rabbit antithymocyte globulin, a "custom-made" pan-anti-T-cell antibody produced in rabbits, is currently being evaluated in the United States and may, within several years, become approved by the Food and Drug Administration. Because we have used this agent for induction of immunosuppression for 10 years in cardiac recipients and because the results appear to be more favorable than those obtained with other agents (horse antithymocyte globulin, antilymphocyte globulin, OKT3), we have reviewed our experience. For the purpose of analysis, all non-bridge-to-transplant cardiac recipients have been divided into three groups on the basis of immunosuppression protocol: group I (March 1979 to January 1983), 28 patients treated with rabbit antithymocyte globulin, steroids, and azathioprine; group II (January 1983 to March 1985), 29 patients treated with rabbit antithymocyte globulin, cyclosporine, and steroids; and group III (March 1985 to January 1989), 98 patients treated with rabbit antithymocyte globulin, cyclosporine, steroids, and azathioprine. Actuarial data showed advantage for group III in survival rate (1 year 94%, 2 years 91%, 3 years 88%), freedom from rejection (30% free at 1 year), freedom from infection (50% free at 1 year), freedom from death from rejection (99% free at 1 year), and freedom from death from infection (97% freedom at 1 year). Actuarial survival rates and freedom from death from rejection and infection are comparable for any of our groups with contemporary published data. In the past 3 years, we have had no death from acute rejection or from posttransplant infection. Time-related rates of infection by etiologic agents have shown a significant reduction in early bacterial, viral, and nocardial infections between groups I and III. With rabbit antithymocyte globulin 200 mg intramuscularly every day for 3 days, our current protocol, T-cells are significantly reduced and local and systemic toxicity is almost unnoticeable. A progressively increasing cyclosporine dose along with rapid tapering steroid and maintenance azathioprine immunosuppressive induction appears to be the therapy of choice in cardiac transplantation.

Heart transplantation in patients with treated breast carcinoma.

Since 1987, five women with end-stage cardiomyopathy and a history of treated breast carcinoma have undergone transplantation at our institution. All patients underwent extensive multidisciplinary pretransplantation evaluation to rule out metastatic disease. Disease-free interval before heart transplantation ranged from 5 to 11 years (mean, 7.6 years). All patients received immunosuppression in accordance with a standard protocol of rabbit antithymocyte globulin, cyclosporine, prednisone, and azathioprine. Mean postoperative follow-up is 49 months. All patients are alive and have no symptoms 18 to 73 months after transplantation. In carefully selected patients with a history of breast carcinoma, heart transplantation can be performed with good functional results and satisfactory late survival.