Studies of blood flow in aorta-to-coronary venous bypass grafts in man.

Pressure-flow measurements were obtained from the vein graft of 57 patients undergoing a single aorta-to-coronary bypass procedure. The flow contour was similar to phasic left coronary artery flow in dogs except for a transient increase during systole possibly related to elongation of the graft. Flow was highest during bypass and decreased to a stable value 30 min after bypass. In 42 patients, flow at this time was 35+/-2 cm(3)/min (mean+/-sem).NO CORRELATIONS WERE DEMONSTRATED BETWEEN FLOW AND THE FOLLOWING: left vs. right grafts, presence or absence of collaterals, total vs. partial block, or the presence or absence of ventricular dyskinesis. In 32 patients, no correlation between these anatomic findings and the presence of reactive hyperemia was demonstrated. In 17 patients, occlusion of the graft for 10 sec resulted in a mean 51.5% flow debt repayment. In nine patients, injection of 0.3 mug of isoproterenol into the graft increased flow from 45+/-6 to 69+/-9 cm(3)/min within 4-7 sec without changes in rate, pressure, time derivative of left ventricular pressure (LV dp/dt), or left ventricular end diastolic pressure (LVEDP). Maximum increases to 87+/-10 cm(3)/min occurred 12-20 sec after injection with concomitant changes in these parameters. Intravenous infusion of norepinephrine did not change vascular resistance, whereas phenylephrine did. In six patients, injection of 0.2 mug of norepinephrine into the graft decreased flow from 49+/-6 to 25+/-5 cm(3)/min within 5-8 sec. Intravenous infusion of 0.15 mg of nitroglycerin decreased coronary vascular resistance from 2.7+/-0.4 to 2.3+/-0.3 mm Hg/cm(3) per min. In five patients, 0.12 mg of nitroglycerin injected into the graft increased flow from 46+/-7 to 71+/-13 cm(3)/min and lasted 20-40 sec.

Absent pulmonary valve syndrome in infancy: surgery reconsidered.

Congenital absence of the pulmonary valve leaflets is generally associated with ventricular septal defect, anular pulmonary stenosis and aneurysmal dilatation of the pulmonary arteries: the absent pulmonary valve syndrome. Symptomatic infants with this syndrome suffer primarily from respiratory insufficiency caused by bronchial compression by the dilatated pulmonary arteries, and have a high mortality rate. Asymptomatic infants are thought to do well, and may have elective surgery late in childhood. Findings in four infants with absent pulmonary valve syndrome are reviewed. One symptomatic infant was successfully treated with closure of a ventricular septal defect and pulmonary arterial plication. One previously asymptomatic infant had a fatal respiratory arrest revealing the complexity of management of infants with absent pulmonary valve syndrome.

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.

Ventricular aneurysm with ventricular tachycardia. Report of a case with epicardial mapping and successful resection.

A case of ventricular aneurysm with refractory ventricular tachycardia is presented. Epicardial mapping was used to localize the site of earliest epicardial activity to the margin of the aneurysm, and subsequent resection of this area abolished the rhythm disturbance.

Aortocoronary bypass surgery: Correlation of angiographic symptomatic and functional improvement at 1 year.

Angiographic changes in the coronary circulation were evaluated in 60 patients 1 year after aortocoronary bypass surgery, and their relation to the postoperative clinical status was examined. Of 124 grafts implanted, 26 were closed, 7 stenotic and 91 (74 percent) patent at 1 year. Progression of occlusive disease occurred in 21 of 57 (37 percent) nongrafted and 78 of 123 (63 percent) grafted vessels. On the basis of location and severity of progression, significant lesions bypassed and patency of grafts, postoperative coronary perfusion was considered optimal in 16 patients (Group I), better in 24 (Group III). Complete freedom from chest pain or lessening of pain (improvement by two New York Heart Association functional classes) occurred in 88 and 79 percent of patients in Group III. Positive preoperative treadmill stress tests became negative after surgery in five of six patients in Group I, five of eight in Grojp II and three of eight in Group III. This study demonstrates that when progression of disease, graft patency and extent of revasculariztion are considered in combination, the postoperative angiographic status of the coronary circulation correlates well with clinical improvement at 1 year. These findings support the hypothesis that improved blood supply to ischemic myocardium is a major factor contributing to relief of angina pectoris after saphenous vein bypass surgery.

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.

Coronary collateral blood flow in acute myocardial infarction.

The evolution and transmural distribution of coronary collateral blood flow in acute myocardial infarction was determined in 24 trained, unanesthetized dogs by injection of radioactive microspheres into the coronary circulation. Acute coronary artery occlusion resulted in a greater decrease in subendocardial flow than subepicardial flow in both the central and marginal zones of the infarct. Coronary collateral blood flow was distributed primarily to the marginal zone and to the subepicardium of the central zone of the infarct. The greatest increase in collateral flow occured between 12 and 18 hours after coronary artery occlusion. By 24 hours after coronary occlusion, blood flow to all areas of the infarct except the subendocardium of the central zone had returned to near control levels. This dispropotionate distribution of coronary collateral blood flow during the early stages of myocardial ischemic injury helps to explain the apparent lack of protection of the subendocardium by collateral flow.

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.

Coronary collateral circulation during stress and the effects of aorta-coronary bypass grafts.

The ability of coronary collateral vessels to supply an adequate volume of blood to the subendocardium during the resting state and during periods of stress was studied. Regional myocardial blood flow was determined by the radioactive microsphere technique. Ameroid constricting devices were placed around the left circumflex coronary artery in 22 adult mongrel dogs. Three months later, regional myocardial blood flow was measured in a normal area of the left ventricle as well as in the area supplied entirely by coronary collateral vessels. Collateral blood flow was sufficient in the resting state to prevent myocardial ischemia distal to a gradually occluded coronary artery. However, in 10 animals (Group I) without aorta-coronary bypass grafts (ACBG), a selective underperfusion of the collateralized subendocardium occurred during periods of stress. In 12 animals (Group II), this selective underperfusion of the collateralized subendocardium with stress was abolished by placing ACBG's distal to the site of the coronary artery occlusion.

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.

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.

Staged correction of pulmonary atresia and absent right pulmonary artery.

Repair of pulmonary atresia with an extra-anatomic conduit has been difficult in patients with absent central pulmonary arteries. Although several methods have been employed successfully, each has inherent problems. Our technique uses a staged approach to complete pulmonary revascularization using the systemic-pulmonary collateral arteries for reconstruction of the involved lung. In our patient, this type of repair was associated with excellent late postoperative symptomatic and hemodynamic results. Complete revascularization of both lungs during correction of pulmonary atresia may improve the surgical management of this condition.

Lengthened intraaortic balloon tubing for intraoperative use.

The intraaortic balloon pump (IABP) is being used with increasing frequency during surgical procedures. The standard length of balloon tubing requires the IABP console to be close to the operating table. This creates a possibility of contamination. A longer balloon tubing is described that permits an increased distance between console and operating table without decreasing effective augmentation.

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)

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.

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.

Early assessment of rest and exercise left ventricular function following coronary artery surgery.

Radionuclide assessment of rest and exercise left ventricular function was performed in 14 patients before, eight days after, and three months after coronary artery bypass grafting (CABG). Resting function was unaltered after operation, although mild increases in heart rate and end-diastolic volume were observed on the eighth postoperative day. In contrast, exercise function was significantly improved at both postoperative time periods. Exercise ejection fraction was 0.54 +/- 0.10 before operation, 0.73 +/- 0.12 at eight days, and 0.64 +/- 0.13 at three months. Before CABG, the exercise-induced increase in stroke volume was achieved by an increase in end-diastolic volume, whereas eight days after CABG this increase was achieved by an increase in contractility (systolic blood pressure/end-systolic volume). By three months, both contractility and end-diastolic volume increased with exercise. Thus, improvement in left ventricular function during exercise can be documented as early as eight days after coronary revascularization. This change may be less pronounced after three months of convalescence, but considerable improvement in ventricular function persists compared to preoperative assessment.

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.

Benign tumors of the lung and bronchus.

Benign tumors of the lung and bronchus are a heterogeneous group of lesions that usually present as asymptomatic, solitary, peripheral lung nodules or, less commonly, as endobronchial lesions causing obstructive symptoms. All endobronchial lesions should be removed surgically to alleviate symptoms and to prevent destruction of distal lung tissue. Parenchymal lesions may present challenging problems in clinical diagnosis and management. Most patients will ultimately require thoracotomy for histologic confirmation of benignity. It is probable that newer diagnostic procedures will allow a more accurate nonoperative diagnosis in certain patients in the near future. At the present time, expeditious limited thoracotomy affords a safe, rapid, and effective treatment for patients with a benign tumor of the lung or bronchus.