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Biomedical subjects

P A Ebert

Publications and source records attributed to P A Ebert.

At least 55 records · Page 3Linked to original sources
PubMed1983

Evaluation of early postoperative coronary artery bypass graft patency by contrast-enhanced computed tomography.

Fifty patients with 117 coronary bypass grafts were studied by contrast-enhanced computed tomography at an average of 5 +/- 4 days after surgery to determine if this technique was a feasible method for detecting early postoperative graft occlusion. The study was limited in only three patients because of incisional chest pain (one patient) or multiple metal clips attached to the graft (two patients). The distal patency of sequential grafts cannot be determined by current techniques. There was a lower graft patency rate (70%) in the 10 patients with perioperative myocardial infarction than in the 40 (95%) without (p less than 0.025), but most regions of infarcted myocardium were perfused by patent grafts. There were eight graft occlusions in eight patients. The graft occlusion rate (30%) was significantly higher (p less than 0.025) in grafts with intraoperative flows less than 45 ml/min. The postoperative complications of myocardial dysfunction, arrhythmia and coronary artery spasm did not correlate with graft occlusion. Early graft occlusion is uncommon (7%) and usually occurs in grafts with low flows or severe distal disease (seven of eight grafts), or both. Thus, the need for early reoperation is very infrequent. It is concluded that contrast-enhanced computed tomography is feasible for the assessment of coronary bypass graft patency. Because early graft occlusion is unusual the technique may be an ideal noninvasive screening method.

Aged↗
PubMed1982

Second operations for pulmonary stenosis or insufficiency after repair of tetralogy of Fallot.

Twenty-four patients with previous surgery for repair of tetralogy of Fallot were in need of subsequent operative procedures for either residual pulmonary stenosis or pulmonary valve incompetence. The second operation was performed 1 to 21 years after the initial repair. The patients with pulmonary valve incompetence had evidence of marked right ventricular dysfunction and required pulmonary valve replacement. The patients with residual pulmonary stenosis had modifications of their pulmonary outflow tract to reduce the gradient. Five of the 15 patients with stenosis required pulmonary valve replacement. Clinical improvement has been good, but objective reversal of right ventricular dysfunction has been difficult to document.

Adult↗
PubMed1982

Technical accuracy and clinical efficacy of thoracic computed tomography.

The technical accuracy and clinical efficacy of thoracic CAT scans in 302 surgical patients were retrospectively reviewed. We conclude that thoracic CAT scans should be ordered selectively since the technical accuracy of existing radiographic studies in detecting disease is equally high (greater than 90 percent) and the clinical efficacy does not differ substantially (less than 16 percent). The accuracy of CAT scans in staging carcinoma (the extent of the lesion or nodes) is only 58 percent. The technical limitations of these scans include (1) a lack of specificity because of the high incidence of false-positive lymph nodes, (2) a low or unreliable yield from needle aspiration, and (3) unreliable findings due to altered anatomy by previous treatment or associated disease. Surgical treatment regarding operability and resectability should not be solely based on CAT scans. These scans appear to be a useful screening test for chronic vascular disease and localization of obscure thoracic infections.

False Positive Reactions↗
PubMed1982

Preliminary experience with aspirin for anticoagulation in children with prosthetic cardiac valves.

Twenty-four children (ages 1 to 18 years, mean 12.2 years) underwent 27 operations for aortic, mitral, or combined aortic and mitral valve replacement. There was 1 operative death. Of the 23 operative survivors (12 aortic, 8 mitral, 3 combined valve replacement), only 5 were given warfarin for long-term anticoagulation. The remaining 18 (10 aortic, 8 mitral valve replacement) were given aspirin (plus dipyridamole in 5). Twelve of the 18 had at least one mechanical valve (11 Björk-Shiley and Beall valves; 1 Björk-Shiley valve was replaced with a Beall disc valve as the child grew). These 18 patients were followed for 1 to 59 months (mean, 20.4 months). There was no thrombotic, embolic, or bleeding complications. There were 2 late deaths (one cardiac). Review of the available literature indicates that in children with prosthetic cardiac valves, aspirin (with or without dipyridamole) provides adequate protection against thromboemboli and avoids the hemorrhagic complications associated with warfarin.

Adolescent↗
PubMed1982

Intrauterine cardiothoracic surgery: the fetal lamb model.

We have developed fetal lamb models of congenital cardiothoracic lesions that have been allowed to progress through birth for physiological study. Simulated lesions, simulated repairs, actual lesions, and actual repairs have been performed in this model. Sixty-two fetal lambs comprised the study group, including 48 in which models were created and 14 controls. Models included pulmonary stenosis, aortic stenosis, and diaphragmatic hernia. Gestational age ranged from 90 to 120 days (0.6 of normal gestation). In each pregnant ewe, laparotomy and hysterotomy were performed under general anesthesia, with care taken to avoid placental vessels. The foreleg was exposed, the appropriate anterior chest wall was isolated, and a thoracotomy was done. Thoracic or cardiac procedures then were performed under controlled transplacental anesthesia and perfusion. Following completion of the procedure, the fetal thoracotomy was closed, sterile antibiotic solution was placed in the amniotic sac, and the hysterotomy and laparotomy were closed. Subsequently the fetus either was allowed to progress to birth and infant study or underwent subsequent intrauterine repair and then was allowed to progress to birth and neonatal study. This fetal lamb model provides reproducible anatomical and pathophysiological lesions to facilitate the development of techniques for repair of such lesions in early infancy. Further, it offers the potential for developing methods of intrauterine cardiothoracic surgical repair.

Animals↗
PubMed1982

Evaluation of infradiaphragmatic total anomalous pulmonary venous connection with two-dimensional echocardiography.

In three newborn infants with infradiaphragmatic total anomalous pulmonary venous connection, the common pulmonary vein was visualized with two-dimensional echocardiography and validated with saline contrast injections. The transducer was placed in the subcostal region in a sagittal body plane so as to image the descending aorta and the vertebral column. The common pulmonary vein, which connected the pulmonary veins to a systemic vein in the abdomen, was seen lying parallel and anterior to the descending aorta and to the left of the inferior vena cava. With peripheral venous contrast injections, contrast echoes first filled the inferior vena cava and then the descending aorta because of obligatory right-to-left atrial shunting. The common pulmonary vein was the only structure that remained free of contrast echoes. Thus, contrast echocardiography provided a method for identifying the site of pulmonary venous drainage and for distinguishing the common pulmonary vein from other structures such as the inferior vena cava. In cyanotic infants with respiratory distress, two-dimensional contrast echocardiography permits a rapid diagnosis of infradiaphragmatic total anomalous pulmonary venous connection.

Diaphragm↗
PubMed1982

Left ventricular outflow enlargement by the Konno procedure.

The optimal management of patients with small aortic anulus or left ventricular outflow tract obstruction remains unclear. Between 1976 and March, 1982; 18 patients have undergone enlargement of their left ventricular outflow tract by means of the Konno or a modification of the Konno procedure. Fourteen of these 18 patients had previous operations for aortic stenosis or tunnel left ventricular outflow tract, and two patients had undergone three previous operations. All 18 patients had symptoms of either heart failure of chest pain, or had electrocardiographic evidence of strain. They ranged in age from 4 years to 58 years, with 13 of the 18 patients being less than 20 years of age. A Dacron patch was used to enlarge the left ventricular outflow tract after incising down the ventricular septum. In all patients, at least a 21 mm valve could be placed, with between 50% and 65% of the valve anulus being made up of natural tissue. The remaining portion of the valve anulus was constructed from the Dacron patch. The patch was extended up to enlarge the ascending aorta, and a pericardial patch was used to close the defect in the right ventricular outflow tract. In all 18 patients the gradient was obliterated at the time of operation. There was one early death in a patient who had previous insertion of a left ventricular apical-aortic conduit in which the heterograft valve had degenerated. There has been one late death because of bacterial endocarditis in a child who also had a parachute mitral valve and evidence of pulmonary hypertension. The remaining 16 patients are functioning well after the Konno procedure. Three are receiving warfarin sodium, and 13 are receiving aspirin. These results suggest that this is an acceptable method of treating patients with small aortic anulus or left ventricular outflow tract obstructions and would appear to have advantages over a left ventricular apical-aortic conduit.

Adolescent↗
PubMed1982

Assessment of saphenous vein graft patency by contrast-enhanced computed tomography.

Early saphenous vein coronary bypass graft patency has been found to range from 82% to 94%. Recent advances in computed tomography have led to the development of a safe, effective, and "relatively noninvasive" means of assessing early graft patency. We designed a prospective study using contrast-enhanced computed tomography (CECT), postulating that selected grafts might be redone prior to the development of pericardial adhesions if early closure was demonstrated. Forty-three random patients undergoing elective coronary artery bypass comprise the study group. All patients underwent CECT study of graft patency an average of 6 days postoperatively (range 1 to 17 days). Ninety of 96 grafts were open, for an early patency rate of 94%. Three of the grafts were closed because of poor run-off or extensive distal coronary atherosclerosis. Two additional grafts were closed, one in a patient with severe atherosclerosis of the ascending aorta and one in a patient having triple vessel bypass using cephalic vein because of limited conduit material. Only one graft was closed without apparent cause and judged potentially suitable for reoperation. CECT was found to be a safe and potentially useful means of assessing early graft patency, particularly in patients sustaining untoward clinical events.

Aged↗
PubMed1982

Surgical management of complete atrioventricular canal.

Successful correction of complete atrioventricular (AV) canal depends on accurate assessment of surgical anatomy and preservation of valve tissue to avoid postoperative valvular insufficiency. From 1975 to 1980 there were 68 patients aged 2 months to 17 years (median age 12 months) who underwent correction for the complete form of AV canal. Forty-six percent had associated anomalies which included patent ductus arteriosus, right aortic arch, pulmonic stenosis, and ostium secundum defect. Two types of repairs were employed: group I-Teflon patch closure of the ventricular septal defect (VSD) by division of the common leaflets into mitral and tricuspid components: Group II-Teflon patch closure of the VSD without division of common leaflets by fashioning the patch between the chordae tendineae and under the common leaflets. The atrial septal defect component was closed separately with pericardium or Teflon. Overall mortality is related to presence of (1) elevated pulmonary vascular resistance (Wood units greater than 4), (2) prior palliative operations, or (3) associated cardiovascular anomalies. Repair of complete AV canal without splitting the common leaflets preserves valve tissue. The act of splitting the common leaflets and reattaching the mitral and tricuspid components to the VSD patch by necessity sacrifices valve tissue. Although this may not be significant in older children, it becomes important in infants, for the sacrificed valve tissue comprises a greater proportion of the whole. Moreover, patch disruption of the reattached mitral and tricuspid components can be avoided if the common leaflets are not split.

Adolescent↗
PubMed1982

Repair of congenital cardiac lesions during the first week of life.

Repair of congenital cardiac defects in the neonatal period has been associated with a high operative mortality thought to be due to the adverse effects of cardiopulmonary bypass. This has prompted the use of closed palliation in such patients. Between 1957 and 1981, 195 of 988 patients (20%) operated in the first year of life were critically ill neonates ages 1-7 days. Fifty-six underwent repair using cardiopulmonary bypass. These included l29 operations at the arterial level, five for aortic stenosis, 19 for pulmonary stenosis and five for transposition of the great arteries using the switch procedure; 25 at the atrial level, eight for transposition of the great arteries, 16 for total anomalous pulmonary venous connection, and one for combined total anomalous pulmonary venous connection and anomalous systemic venous connection; and two at the ventricular level, one for tetralogy of Fallot and one for double-outlet right ventricle. The hospital survival rate in this group was 91%. Palliations using cardiopulmonary bypass were performed in an additional 27 patients, including right ventricular outflow tract patches in 20. The survival rate in this group was 73%. The survival rate was 100% for closed repairs and 76% for palliations. These results demonstrate that cardiopulmonary bypass per se is not a determinant of survival in the neonate; an effective repair combined with proper diagnostic techniques and postoperative management are probably the critical factors.

Cardiopulmonary Bypass↗
PubMed1981

Reduction of myocardial wall tension during cold pressor stress after myocardial revascularization.

The effects of myocardial revascularization on cardiac function remain controversial despite clinical improvement. A study was designed to determine the effects of revascularization on the myocardial response to stress. Stress was induced using the cold pressor (CP) test in which th patient places his arm in ice water for one minute. All patients were tested before and one week and six months after surgery. Ejection fraction and cardiac index were determined with a noninvasive nuclear technique. Fifteen patients were studied (five patients received propranolol hydrochloride therapy after surgery, and ten patients did not receive this therapy). Cuff systolic blood pressure (BP) was obtained simultaneously with the nuclear study. The double product (heart rate x systolic BP) was calculated and used as an index of stress induced by the CP test. The results indicate that, during stress, myocardial wall tension is significantly reduced after adequate revascularization (565 dynes/cm from a preoperative value of 458 dynes/cm [P less than .001].) Patients achieved a higher cardiac index (3.58 L/min/sq m as compared with a preoperative value of 2.51 L/min/sq m) and double product (13,600 as compared with a preoperative value of 11,900) while, at the same time, tension was reduced. This suggest that increasing coronary blood flow through bypass surgery reduces myocardial wall tension during stress. This may be the reason myocardial revascularization achieves a lower incidence in late myocardial infarction when compared with medical therapy.

Blood Pressure↗
PubMed1981

Repair of combined total anomalous pulmonary venous connection and anomalous systemic connection in early infancy.

A simple intraatrial reconstruction can be utilized in infants to simultaneously correct both the systemic and pulmonary venous returns. Two infants with polysplenia syndrome treated in the first months of life are presented. One had levocardia and combined total anomalous pulmonary venous connection (type II-Cardiac) and anomalous systemic venous connection. The other had dextrocardia L-loop, L-normal great arteries, and combined total anomalous pulmonary venous connection (type II-Cardiac) and anomalous systemic venous connection. The posterior position of the systemic atrioventricular valve and systemic ventricle in both patients allowed the use of this reconstructive technique. The extensive size and transverse position of this patch when used in the infant may require both continued postoperative controlled ventilation until it stiffens and prolonged attention to postoperative cardiac care until adaptation of the infant heart to the new atria can occur. Early restudy and reoperation should be performed if signs of stenosis develop.

Dextrocardia↗
PubMed1981

Superior vena caval obstruction after Mustard's operation: detection by two-dimensional contrast echocardiography.

To assess superior vena caval (SVC) obstruction after the Mustard operation for transposition of the great arteries, we performed two-dimensional contrast echocardiography (2-D contrast echo) in 18 patients, ages 1-9 years. Sterile saline was injected into a peripheral scalp or arm vein while the junction of the inferior vena cava (IVC) and the systemic venous atrium (SVA) was imaged from the subcostal long-axis plane. The results of 2-D contrast echo were compared with those obtained at cardiac catheterization. In nine patients, contrast passed from the SVC to the SVA and the IVC remained free of contrast echoes. At catheterization, these patients had no SVC obstruction by angiography and minor SVC-SVA mean pressure differences (0-4 mm Hg). In five patients, contrast passed from the SVC into the SVA. Within a few cardiac cycles, contrast from azygos-IVC collateral vessels flowed in the IVC toward the SVA. At catheterization, these patients had partial SVC obstruction by angiography and SVC-SVA mean pressure differences of 9-13 mm Hg. In four patients, the SVA was filled only by contrast arriving from the IVC by way of azygos-IVC collateral vessels. At catheterization, these patients had complete SVC obstruction and SVC-SVA mean pressure differences of 14-20 mm Hg. Two-dimensional contrast echocardiography is a simple, accurate, noninvasive method for detecting SVC obstruction after Mustard's operation and allows differentiation of complete from partial SVC obstruction.

Cardiac Catheterization↗
PubMed1981

Persistent stenosis and deformity of the right pulmonary artery after correction of the Waterston anastomosis.

Between July, 1975, and July, 1979, 16 patients with cyanotic heart disease and previously constructed ascending aorta-right pulmonary artery (AA-RPA) shunts underwent subsequent operations. Fourteen of the 16 had significant physiological and anatomic problems associated with the shunts. Eight had kinking and preferential flow to the right pulmonary artery (RPA), four had preferential flow without kinking, and two had small pulmonary arteries bilaterally. Various techniques were used to close the RPA after Waterston takedown: direct suture in four, pericardial patch in five, prosthetic patch in four, and conduit in three. Five patients required reoperation 3 months to 3 years after Waterston dismantling because of persistent deformity of the RPA. Four patients had pericardial patch reconstruction of the RPA and one had direct closure of the opening in the RPA when the Waterston shunt was dismantled. All five patients received prosthetic patch enlargment of the RPA either alone or with a conduit. The four surviving patients are doing well 7 to 15 months following repair. Three have been studied angiographically and have been found to have no pulmonary artery deformity.

Angiography↗
PubMed1981

Repair of dissection of the thoracic aorta. Evaluation of false lumen utilizing computed tomography.

During the period 1975 to 1980, 21 patients with thoracic aortic dissections underwent surgical treatment. The operative technique was resection and tube graft replacement of the segment of the aorta containing the entry point into the false channel. Eleven Type A and 10 Type B dissections were resected. The hospital survival rate was 95%. The single operative death occurred in a patient with an acute Type A dissection. Three patients had total resection of the dissected segment; three had clotted false lumina; five had distal anastomosis to true and false lamina; and 10 had distal anastomosis to the true lumen only, with proximal entry into the false lumen obliterated by incorporating both intimal and adventitial walls in a single suture line. The late survival rate was 95% (mean 32 months, range 8 to 63 months). No late ruptures occurred. Computed tomography (CT) with contrast enhancement was used to evaluate the aorta and any residual false lumen at follow-up. Seven of eight patients in whom obliteration was attempted and CT scans performed demonstrated persistence of false lumen perfusion; in six of the eight, preoperative angiograms were adequate for evaluation of false lumen runoff. Major vessels arose from the false lumen in all cases, except in the one patient in whom obliteration was later successful. This report demonstrates that there is persistence of false lumen perfusion in patients in whom obliteration is attempted, and the mechanism of this persistence is the presence of major vessel runoff. It suggests that the mechanism by which long-term survival is achieved is by resection of the segment of aorta containing the entry site, which is frequently the site of subsequent enlargement and rupture, rather than obliteration of the false channel.

Adult↗
PubMed1980

Atrial repairs of infant complex congenital heart lesions. Emphasis on the first 3 months of life.

From 1975 to 1980, 106 infants in the first year of life with complex cardiac anomalies underwent isolated intra-atrial repair; 70 were in the first 3 months of life. Of these 70, 39 were 1 to 3 months old, 15 were 1 week to 1 month old, and 16 were less than 1 week old. The median age was 70 days, the range, 1 to 360 days. These infants included 74 with transposition of the great arteries, 28 with total anomalous pulmonary venous connection, and four with complex lesions (cor triatriatum and combined total anomalous pulmonary venous connection and anomalous systemic connection). Overall survival was 95%; for those in the first 3 months of life, 96%; for those in the first month, 94%; and for those in the first week, 100%. Age was not a determinant of survival. Attempts to delay surgical intervention once symptoms appear only results in clinical deterioration and interim mortality.

Age Factors↗