Efficacy of the internal mammary artery in combined aortic valve replacement-coronary artery bypass grafting.

BACKGROUND: While internal mammary artery (IMA) use predicts improved survival after coronary bypass grafting (CABG), it remains unknown whether patients undergoing concomitant aortic valve replacement (AVR) realize a similar benefit. METHODS: All patients at a single teaching institution, undergoing combined AVR-CABG, which included a graft to the left anterior descending coronary artery (LAD) from 1984 to 1994 (n = 227) were examined retrospectively. RESULTS: Patients receiving an IMA graft (yesIMA, n = 135) and patients receiving only saphenous vein grafts (nonIMA, n = 92) were not different in their presenting symptoms, or in their incidence of preoperative risk factors. The patients with IMA were more likely to be male, have a later year of operation, be younger, and have a greater body surface. Morbidity was not different between groups. IMA use did not affect 30-day mortality. Long-term actuarial survival was greater in the group with IMA (63% +/- 7% vs 42% +/- 6% at 5 years, p < 0.01). A multivariate Cox proportional hazards model demonstrated that use of an IMA graft improved survival, while recent myocardial infarction, diabetes, earlier year of operation, and lower ejection fraction diminished long-term survival. The relative risk of IMA grafting was 0.570. CONCLUSIONS: Within the limits of a retrospective analysis, patients in a modern era of cardiac operation, who undergo combined AVR-CABG, do not suffer increased morbidity from IMA use, and may realize a survival benefit from use of the IMA as a conduit for bypass of the LAD coronary artery.

Collagen subtypes III and IV expression in human vein graft atherosclerosis.

This study examined the expression of collagen subtypes III and IV in a series of freshly excised human venous coronary artery bypass grafts. The results of this study demonstrate that these collagen subtypes are differentially expressed in vein graft atherosclerosis.

In-hospital and long-term outcome after porcine tricuspid valve replacement.

Porcine bioprostheses are often used for tricuspid valve replacement, yet the long-term outcome after this procedure is not well documented. Therefore, the records of 129 patients undergoing tricuspid valve replacement with Carpentier-Edwards (n = 88) or Hancock (n = 41) prostheses between 1975 and 1993 were reviewed. The operation required a repeat median sternotomy in 66 of 129 (51%) patients, whereas 67 of 129 (52%) underwent double or triple valve replacement. Operative mortality was 14% (2/14) in patients undergoing first-time isolated tricuspid valve replacement and 27% (35/129) overall. Survival at 5, 10, and 14 years was 56% +/- 5%, 48% +/- 5%, and 31% +/- 9%, and freedom from tricuspid reoperation at 5, 10, and 14 years was 96% +/- 3%, 93% +/- 4%, and 49% +/- 17%. No valve thrombosis was observed. In this largest reported series of porcine bioprostheses in the tricuspid position, long-term freedom from valve-related events was excellent because of a low incidence of valve thrombosis and a valve durability of 13 to 15 years in a population with limited life expectancy.

Comparison of anticoagulation regimens after Carpentier-Edwards aortic or mitral valve replacement.

BACKGROUND: To identify the optimal use of anticoagulants after Carpentier-Edwards valve replacement, a retrospective study of all patients undergoing Carpentier-Edwards aortic (N = 378) or mitral (N = 370) valve replacement was done. METHODS AND RESULTS: At the time of hospital discharge, 103 patients were managed with warfarin, 509 with aspirin alone, and 136 with no anticoagulation or antiplatelet therapy. Over the first 90 days after aortic or mitral valve replacement, the linearized rate of hemorrhage was greater for warfarin than for aspirin or no therapy (16.7 +/- 7.6%, 3.4 +/- 1.7%, and 3.1 +/- 3.1% per patient-year, respectively; P = .03). After aortic valve replacement, aspirin provided a low rate of thromboembolism (0.8 +/- 0.2% per patient-year), not significantly different from warfarin or no treatment (2.9 +/- 1.6% and 1.5 +/- 0.6% per patient-year) (P = .07). After mitral valve replacement, no single treatment was most advantageous because the rate of hemorrhage over the first 90 days for warfarin was equivalent to the 90-day rate of thromboembolism with aspirin or no therapy. CONCLUSIONS: Anticoagulation after Carpentier-Edwards mitral valve replacement may be best guided by individual patient characteristics. Within the limits of a retrospective analysis, these data support the routine use of aspirin alone after Carpentier-Edwards aortic valve replacement, both in the first 90 days and long-term.

Topical thrombin and acquired coagulation factor inhibitors: clinical spectrum and laboratory diagnosis.

Topical bovine thrombin preparations are used extensively in cardiovascular, neurosurgical, and otolaryngologic procedures. Patients who are treated with these topical thrombin preparations may develop antibodies to bovine coagulation factors that may cross-react with the endogenous human clotting proteins. We have identified four patients with acquired factor inhibitors following exposure to topical thrombin at Duke University Medical Center and summarize these cases in addition to 13 patients previously reported in the literature. In most cases, the inhibitor developed following a second (or subsequent) exposure to topical thrombin. The clinical course was extremely variable, ranging from totally asymptomatic to life-threatening hemorrhage. The most consistent laboratory abnormality was a prolonged bovine thrombin clotting time, which corrected, at least partially, when human thrombin was substituted for bovine thrombin. Some of these patients also developed factor V inhibitors with prolonged prothrombin and activated partial thromboplastin times. Although these patients have prolonged clotting times, they should not be considered "autoanticoagulated," since thromboembolic complications can still occur. Therapeutic intervention is largely empirical and depends on the clinical manifestations of the individual patient.

Determinants of early versus late cardiac death in patients undergoing coronary artery bypass graft surgery.

Most analyses of risk factors affecting survival after coronary artery bypass graft surgery have not differentiated among factors that influence early and late survival. For this reason, a multiphase model was applied to survival data from 2,967 patients undergoing a first coronary artery bypass graft at the Duke University Medical Center between 1969 and 1984. There were 709 deaths during follow-up to 19.6 years. The data were analyzed using a multivariable survival model that separates the underlying hazard function into as much as three different phases, each incorporating separate risk factors. Two distinct phases were detected. One phase dominated early survival (0-1 year), and the second phase dominated late survival (greater than 1 year). Surgery performed earlier in our experience was associated with elevated risk of dying in both phases but with different magnitudes, whereas lower ejection fraction, greater extent of coronary disease, older age, conduction abnormality, and history of hypertension were associated with elevated risk of dying similarly in both phases (p less than 0.05). Severity of angina symptoms and lower weight were associated with an elevated risk of dying only in the early phase (p less than 0.05; because few of the patients were obese, estimates of the relative risk of morbid obesity could not be estimated), whereas vascular disease, diabetes, and extent of myocardial damage were associated with an elevated risk of dying only in the late phase (p less than 0.05). These data illustrate both the differential influence of risk factors over time and the importance of multiphase models.

Candida mediastinitis after a cardiac operation.

Candida mediastinitis is a rare condition characterized by a high mortality and chronic morbidity, Including the present review, only 39 cases have been described, 67% occurring after a cardiac operation. Candida mediastinitis has a 55% mortality in the postoperative setting and a mortality of 92% among patients without a prior cardiac procedure. Although no patient survived Candida mediastinitis without surgical drainage of the mediastinum, survival was 85% among 13 patients who underwent operative mediastinal drainage. Chronic wound infection developed in 6 survivors of operative drainage without muscle flap closure, but in all patients closed with vascularized flaps, healing ultimately occurred. Aggressive surgical management with mediastinal drainage, sternal debridement, and early wound closure with vascularized flaps are essential to minimize the otherwise high morbidity and mortality of Candida mediastinitis.

The Blalock-Taussig shunt: an analysis of trends and techniques in the fourth decade.

The original description of the Blalock-Taussig shunt was published in 1945 and represented the first direct surgical procedure for the treatment of cyanotic congenital heart disease. The present study analyzes the results of Blalock-Taussig shunts performed at Duke University Medical Center during the fourth decade since the original description of the procedure. From 1975 to 1984, 53 classic and 24 modified Blalock-Taussig shunts were performed with a hospital mortality of 8%. These deaths occurred in critically ill patients with either pulmonary atresia or complex congenital cardiac lesions. The results of the early group (1975-1979) were compared to the late group (1980-1984) of patients. There was a greater proportion of infants less than 1 week of age in the late group, and the actuarial event-free shunt survival following operation was significantly better in the late group. This improvement in the late group was apparent both in patients receiving classic and modified Blalock-Taussig shunts and probably represents the effects of advances in microsurgical technique as well as improvement in the support of critically ill infants at the time of surgery by pediatric anesthesiologists and neonatologists. The data in the present study indicate that the mortality associated with Blalock-Taussig shunting is related to the condition of the patient at the time of surgery and the underlying cardiac pathology rather than the age of the patient at the time of shunting. The efforts to further reduce morbidity and mortality associated with Blalock-Taussig shunting should therefore be directed primarily to the support of infants during the preoperative and intraoperative phases of care.

The evolution of medical and surgical therapy for coronary artery disease. A 15-year perspective.

To elucidate the factors associated with improved survival following coronary artery bypass surgery, we studied 5809 patients receiving medical or surgical therapy for coronary artery disease. Three factors were associated with a significant surgical survival benefit: more severe coronary disease, a worse prognosis with medical therapy, and a more recent operative date. Patients with more extensive coronary obstruction had the greatest improvement in survival. Patients with a poor prognosis because of factors such as older age, severe angina, or left ventricular dysfunction had a reduction in risk that was proportionate to their overall risk on medical therapy. Survival with surgery progressively improved over the study period and by 1984 surgery was significantly better than medical therapy for most patient subgroups. Thus, contemporary coronary revascularization is associated with improved longevity in many patients with ischemic heart disease, especially in those with adverse prognostic indicators.

Changing efficacy of coronary revascularization. Implications for patient selection.

To evaluate the potential impact of patient selection for coronary artery bypass graft surgery on long-term survival, the outcomes of 5,809 consecutive patients with symptomatic coronary disease documented by angiography at Duke University Medical Center were examined. Over the entire study period (1969-1984), surgical therapy was associated with improved survival compared with medical therapy whether or not adjustment was made for imbalances in baseline prognostic factors. When patients were categorized according to coronary anatomy and left ventricular function, patients with multivessel disease and poor left ventricular function had a greater long-term survival benefit with surgery than did patients with less coronary artery disease and better left ventricular function. When 5-year survival rates were examined as a function of operative risk, a direct relation was found between estimated operative risk and the medical-surgical survival difference. For patients with an operative risk of 1%, the expected 5-year mortality with surgical therapy was 3% versus 8% with medical therapy (an absolute survival difference at 5 years of 5%). In comparison, for patients with an operative risk of 5%, the expected 5-year mortality with surgery was 10% versus 23% with medical therapy (an absolute survival difference at 5 years of 13%). Over 50% of patients with significant coronary artery disease undergoing cardiac catheterization have an estimated operative mortality risk under 2.5%. These patients would be expected to have a small survival advantage treated surgically. As operative mortality rates are subjected to increasing public scrutiny, selection of low-risk patients will reduce the overall benefit of the operation to the population.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of cardiopulmonary bypass on eicosanoid metabolism during pediatric cardiovascular surgery.

Cardiopulmonary bypass in children with congenital heart disease is associated with significant morbidity manifested by increased complement degradation products, heightened pulmonary vascular activity, and coagulopathy. In adults with cardiac disease, the prostaglandins (eicosanoids) have been shown to contribute to the pathophysiologic response to extracorporeal circulation. This study assessed the effect of cardiopulmonary bypass in infants and children on two potent eicosanoids: thromboxane, a vasoconstrictor and platelet aggregating agent, and prostacyclin, a vasodilator and platelet disaggregating agent. The biochemical profiles of thromboxane and prostacyclin were evaluated in temporal relationship to selected parameters of platelet loss and pulmonary vascular hemodynamics during and after cardiopulmonary bypass. Twenty-one children, aged 3 days to 9 years, with congenital heart defects who were undergoing repair with cardiopulmonary bypass were studied. Nine pediatric patients undergoing palliative heart operations with no cardiopulmonary bypass served as the control group. In the group having cardiopulmonary bypass, the thromboxane concentration significantly increased during bypass (195 +/- 10 to 910 +/- 240 pg/ml, +/- standard error of the mean, p less than 0.005), whereas the control group demonstrated no significant change in thromboxane concentration. The highest thromboxane values were seen in the youngest patients (p less than 0.002). There was no significant correlation between thromboxane changes with alterations in pulmonary vascular resistance, platelet loss, duration of cardiopulmonary bypass or aortic cross-clamping. Prostacyclin levels rose significantly in both the bypass group (100 +/- 20 to 570 +/- 80 pg/ml, p less than 0.01) and in the control group (109 +/- 44 to 589 +/- 222 pg/ml, p less than 0.01), which apparently is due to surgical manipulation of vascular endothelium. These data show that eicosanoid production is significantly altered in children during cardiopulmonary bypass. Although thromboxane, a potent vasoconstrictor, is produced in significant amounts during and after cardiopulmonary bypass, our data show that thromboxane does not directly mediate changes in pulmonary artery hypertension and is not quantitatively related to platelet loss during pediatric cardiovascular operations.

The changing survival benefits of coronary revascularization over time.

Previous comparisons of medical and surgical therapy for coronary artery disease were performed in the 1970s and may need to be updated to reflect current treatment efficacy. The purpose of this investigation was to determine the impact on long-term patient survival of changes over time in medical and surgical therapy. Among 5125 patients referred for catheterization between 1969 and 1984, 2261 underwent surgery, and 2864 received medical therapy. Survival in both medically and surgically treated patients improved over time. The improvement in medical patients was due to less sick patients being treated (a decreasing baseline risk), while that observed in surgical patients was due to refinements in care. The rate of improvement in survival over time was much greater in surgical patients, and the difference as compared with medical therapy was highly significant (treatment interaction with time p less than .0001). Estimates of 5 year survival adjusted for baseline risk factors for a patient in 1977 with one-, two-, or three-vessel disease and an ejection fraction of 0.40 were 0.88, 0.80, and 0.64 in medically treated, and 0.88, 0.87, and 0.80 in surgically treated patients. Corresponding projected estimates for 1984 were unchanged for medical patients but improved for surgical patients (0.93, 0.92, and 0.90). Thus, the projected survival benefits of surgery in 1984 appear more significant for all categories of coronary artery disease because of a differential improvement in surgical therapy. These data are relevant to therapeutic decision making for current patients and emphasize the importance of continued analysis of this topic as treatment efficacies change over time.

Primary cysts and neoplasms of the mediastinum: recent changes in clinical presentation, methods of diagnosis, management, and results.

Major changes have recently occurred in the clinical presentation, diagnosis, and management of primary lesions of the mediastinum. New diagnostic techniques and improved therapy have led to more objective preoperative diagnoses as well as better long-term results. These features are clearly demonstrated in a series of 400 consecutive patients with primary lesions of the mediastinum seen at Duke University Medical Center. Of these, 99 (25%) had a primary cystic lesion. The primary tumors included thymic neoplasms (17%), neurogenic tumors (14%), lymphoma (16%), germ cell tumors (11%), and a miscellaneous group. Malignant neoplasms were present in 166 patients (42%). The anterosuperior mediastinum was the most commonly involved site of a primary cyst or neoplasm (54%), followed by the posterior mediastinum (26%) and the middle mediastinum (20%). Symptoms were present in 62% of the patients and included chest pain (30%), dyspnea (16%), fever and chills (20%), and cough (16%). Of the lesions found on routine chest roentgenograms, 83% were benign. In contrast, 57% of the lesions in symptomatic patients were malignant. Prior to 1967, 94% of asymptomatic lesions were benign, but this figure has now decreased to 76%. Fifty percent of symptomatic patients had a malignant neoplasm before 1967 compared with 62% after that year. Newer diagnostic techniques have greatly enhanced the accuracy of the preoperative diagnosis. They include radioisotopic scanning, monoclonal antibodies, hormonal assay, electron microscopy, fine-needle aspiration biopsy, computed tomographic scans, and magnetic resonance imaging. Each has a definite role and is specifically illustrated as being quite important in this series.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway obstruction by vascular anomalies. Importance of telescopic bronchoscopy.

This review of 28 cases of airway obstruction by vascular anomalies in the past 6 years emphasizes the importance of these anomalies as causes of obstruction, stridor, and apnea in infants as well as the important contribution of telescopic bronchoscopy to the recognition of these lesions, especially compression of the trachea by the innominate artery. There were 20 patients with compression by the innominate artery; four were surgically corrected. Seven vascular ring anomalies were all corrected by operation as was an enlarged left atrium and malformed mitral valve in one patient. Vascular anomalies caused 26% of the obstructive airway lesions in a series of infants who had bronchoscopy for obstruction, stridor, or apnea. Failure to diagnose and treat these entities may result in progressive respiratory embarrassment and even death. Barium esophagogram and aortic arch arteriogram, the traditional modalities for diagnosing vascular rings, may fail to identify tracheal compression by enlarged cardiac chambers or the more common "anomalous" innominate artery. Telescopic bronchoscopy will identify tracheal compression by the innominate artery; furthermore, it will identify the area of compression by the vascular ring. Observation of the compressed area during corrective surgery ensures that the operative manipulations are appropriate and successful in relieving the obstruction. This observation can be facilitated by televised monitoring and videotaping.

Prognostic effect of bundle branch block related to coronary artery bypass grafting.

The incidence and prognostic effect of the development of new perioperative ventricular conduction abnormalities were examined in all patients undergoing coronary artery bypass surgery at Duke University Medical Center between 1976 and 1981. Of the 913 patients included, transient (resolved before discharge) ventricular conduction abnormalities developed in 156 (17%) and persistent (until discharge) changes developed in 126 (14%). Complete right bundle branch block (BBB) was the most frequent type of new ventricular conduction abnormality, followed by left anterior hemiblock and incomplete right BBB (found in 60%, 26%, and 9%, respectively, of all patients with transient changes and 29%, 33% and 26% of all patients with persistent changes). Development of new ventricular conduction abnormalities was most strongly related to date of operation (p less than 0.0001, univariate chi 2 = 122), increasing from 2% transient and 7% persistent in 1976 to 36% transient and 22% persistent in 1981. The incidence was also higher in older patients. Preoperative ejection fraction and number of diseased vessels were related to development of perioperative ventricular conduction abnormalities but were not independently related after adjustment for other baseline characteristics. Contrary to findings in other studies, development of new perioperative ventricular conduction abnormalities, including isolated new left BBB, did not worsen the survival rate in patients followed up to 3 years after surgery.

Spinal cord infarction following intraaortic balloon support.

Infarction of the lumbar and sacral spinal cord was demonstrated at autopsy of a 72-year-old man in whom acute paraplegia developed following coronary artery bypass grafting and atrial septal defect repair with intraoperative insertion of an intraaortic balloon. Autopsy findings showed that infarcts of the spinal cord and other key organs were caused by critical occlusion of small arterioles by cholesterol emboli. These emboli apparently arose as a result of the fragmentation of atheromatous plaques within the aorta during use of the intraaortic balloon pump with subsequent embolization and occlusion of small blood vessels.

Physiological rationale for a bidirectional cavopulmonary shunt. A versatile complement to the Fontan principle.

The original Fontan procedure included a classic superior vena cava-to-right pulmonary artery (Glenn) shunt. Subsequent experience demonstrated that this anastomosis was not essential and was an unnecessary commitment of the larger right pulmonary circulation to the smaller blood volume of the superior vena caval return. With application of the Fontan principle to more complex cardiac malformations, there has been a reconsideration of possible benefits of a cavopulmonary shunt in selected patients. A modified shunt from the divided end of the superior vena cava to the side of the undivided right pulmonary artery utilized in 21 patients is described. This shunt is designed to allow bidirectional pulmonary arterial distribution of both superior vena caval inflow and right atrial outflow after completion of the Fontan procedure. Twelve patients had the bidirectional shunt performed prior to a Fontan operation; five of these had a subsequent atriopulmonary connection and seven await operation. Eight patients had construction of this shunt at the time of their Fontan procedure. One patient had a bidirectional shunt constructed following atriopulmonary anastomosis to help relieve right atrial outflow obstruction. Two patients with univentricular heart undergoing simultaneous Fontan procedure and a bidirectional shunt died while in the hospital. The remaining 19 patients have been followed up for 2 months to 9 years with one late sudden death at 9 years. There have been no bidirectional cavopulmonary shunt failures, stenoses, kinks, or recognized pulmonary arteriovenous malformations. Postoperatively, eight patients had assessment of pulmonary distribution of shunt blood flow by angiography. Seven of these patients were also evaluated by radionuclide angiography. Superior vena caval blood flow via the bidirectional cavopulmonary shunt tended to be greater to the right lung, but bilateral pulmonary flow was documented in all but one patient. After Fontan operation, six of seven patients tested also demonstrated bilateral distribution of atriopulmonary flow. We concluded from our experience that this modified shunt provides excellent relief of cyanosis, allows bidirectional pulmonary distribution of both superior vena caval return and also the right atrial blood flow after atriopulmonary connection, and may be done before, with, or after a Fontan procedure and is compatible with all currently recommended modifications. Perioperative hemodynamic adjustments to the Fontan procedure may be improved by reducing atrial volume, and this may also be of potential benefit in the long-term adaptation to Fontan physiology by minimizing atrial distention.