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Biomedical subjects

C S Weldon

Publications and source records attributed to C S Weldon.

At least 19 recordsLinked to original sources
PubMed1988

Preoperative three-dimensional reconstruction of the heart and great vessels in patients with congenital heart disease. Technique and initial results.

Magnetic resonance images have been obtained preoperatively in six patients with congenital heart disease. Contiguous sequences of electrocardiogram-triggered spin-echo images have been reconstructed in three-dimensional form to define the size and anatomic relationships to the great vessels and internal cardiac structures. Findings of magnetic resonance imaging were corroborated by angiographic and sector-scan echocardiographic studies and at operation. Individual scan slices were manually edited to separate the heart and great vessels from the blood within them and from extracardiac structures. Surface reconstruction software originally developed for craniofacial and orthopedic surgical planning was adapted for processing of cardiac magnetic resonance image sequences. Preoperative three-dimensional magnetic resonance imaging reconstructions were obtained in patients with aortic coarctation with ventricular septal defect, hypoplastic left ventricle, pulmonary artery atresia with ventricular septal defect, atrial septal defect, partial atrioventricular canal defect with anomalous pulmonary venous drainage, and tetralogy of Fallot with peripheral pulmonary artery stenosis. The reconstructions showed anatomic findings consistent with two-dimensional magnetic resonance imaging, echocardiography, cineangiography, and intraoperative findings. The three-dimensional images have a format that is familiar and consistent with the gross intraoperative appearance of the heart and great vessels. These three-dimensional images can facilitate the interpretation of magnetic resonance scan findings for cardiac surgeons without the sacrifice of significant clinical information.

Adolescent↗
PubMed1984

Surgical management of hypoplastic right ventricle with pulmonary atresia or critical pulmonary stenosis and intact ventricular septum.

Our experience with the surgical management of hypoplastic right ventricle with intact ventricular septum includes 26 patients with pulmonary atresia and 4 with critical pulmonary stenosis. Group 1 consisted of 8 neonates managed initially by transventricular valvotomy; 6 later required a secondary procedure, with 100% survival. Group 2 had 11 neonates managed by aorta-pulmonary artery shunting without operative death. However, only 3 have survived over the long term and 1 has required an additional shunt procedure. Group 3 had 9 infants who underwent concomitant valvotomy and shunting. There were 4 operative deaths and 1 late death. Finally, Group 4 included 2 infants managed by primary repair at 3 days and 6 days old with prosthetic enlargement of the right ventricle; 1 required the addition of a shunt. Both are alive. Seven of the 15 patients in Groups 1, 2, and 3 who survived neonatal palliative procedures have undergone reparative operations. Two had no growth of the right ventricle and underwent repair after conversion to tricuspid atresia, by a Fontan procedure. Five had prosthetic enlargement of the right ventricle in childhood with 1 late death. Findings of this review were as follows: (1) effective palliation of pulmonary atresia and intact ventricular septum or critical pulmonary stenosis with cavitary hypoplasia of the right ventricle is rare unless transventricular flow can be established; (2) establishment of transventricular flow produces a high incidence of cavitary "growth," which permits later repair; (3) the Fontan operation is available for repair in patients who have no cavitary growth; and (4) when all three portions of the right ventricular cavity can be identified by angiography, a primary repair can be performed in the neonatal period with a good long-term prognosis.

Aorta↗
PubMed1983

Current management of transposition of the great arteries: immediate septostomy, occasional prostaglandin infusion, and early Senning operations.

Between January, 1979, and September, 1982, 30 infants with dextro(D)-transposition of the great arteries were managed with the Senning procedure for transposition of ventricular inflow. In 11 infants under 6 months of age, there were no associated cardiac malformations and no hospital deaths. Among 17 infants operated on between the ages of 6 and 12 months, 6 had associated cardiac malformations, and there were 2 hospital deaths. Two infants in the series were over 12 months of age; 1 had an associated malformation, and there were no hospital deaths. Analysis of cardiac rhythms in the postoperative period demonstrates that the first 2 patients operated on continue to have persistent junctional escape rhythm, while the remaining 26 survivors are in sinus rhythm. Twenty-four-hour Holter monitoring performed in 24 patients showed only 9 patients to be in sinus rhythm throughout the entire recording period. Seven patients had occasional atrial and ventricular premature contractions; the remainder had episodes of sinus arrest with junctional escape rhythm. Evidence of pulmonary caval or pulmonary venous obstruction has not appeared in any patient. Recently introduced technical modifications to the Mustard procedure have improved the results of that operation in regard to rhythm disturbances and baffle obstruction to venous return. This series, therefore, does not demonstrate superiority of the Senning procedure over the Mustard procedure. However, since results comparable to those of the Mustard procedure can be obtained in very young infants using the Senning operation along with deep hypothermia and circulatory arrest, the Senning procedure is deemed preferable to the Mustard procedure for this age group because of the ease with which it can be performed and because the procedure eliminates surgical judgment, and thereby surgical error, in the location of suture lines.

Cardiac Catheterization↗
PubMed1983

Dysrhythmias following the Senning operation for dextro-transposition of the great arteries.

Twenty-nine patients have undergone the Senning operation for repair of dextro-transposition of the great arteries (TGA) since 1979 at St. Louis Children's Hospital. The early mortality has been comparable to that reported for the Mustard operation (10%). Electrocardiograms (ECGs) following the Senning operation reveal abnormalities similar to those noted after the Mustard operation; 63% of survivors were in normal sinus rhythm 1 week postoperatively, and 86% demonstrated normal sinus rhythm at a mean of 15 months after operation. Twenty-four hour ambulatory monitoring revealed normal sinus rhythm in 35% and occasional premature atrial or ventricular contractions in another 30%. No cases of sudden unexpected death have been noted, and no pacemakers have been inserted. Possible mechanisms for rhythm disturbances following venous transposition operations are discussed.

Arrhythmias, Cardiac↗
PubMed1982

Improvement of left ventricular function after ligation of the anomalous left coronary artery during infancy.

Considerable controversy surrounds the optimal management of symptomatic infants with anomalous origin of the left coronary artery from the pulmonary artery; this includes the timing and type of surgical intervention. Long-term follow-up was obtained on three patients who had simple ligation of the anomalous left coronary artery at or before 8 months of age; long-term follow-up on an adolescent treated with a saphenous vein bypass graft from the aorta to the coronary artery was available for comparison. Remarkable increase in left ventricular contractility was observed in the three patients treated only by simple ligation of the anomalous left coronary artery during infancy. Thallous chloride T1 201 exercise studies disclosed no perfusion abnormalities in any of the patients despite angiographically demonstrable wall-motion abnormalities in two of the four patients. Our study suggests that simple ligation of the anomalous left coronary artery near its origin in patients with angiographically detectable left-to-right shunting can provide long-term survival with good left ventricular function and minimal clinical complaints.

Adolescent↗
PubMed1981

Treatment of d-transposition of the great arteries: management of hypoxemia after balloon atrial septostomy.

Between 1975 and 1979, a group of 43 patients with d-transposition of the great arteries were diagnosed and underwent Rashkind balloon atrial septostomy at the time of initial catheterization. Thirty-six (88 percent) survived to the time of intraatrial baffle repair, and 31 (72 percent) are long-term survivors, 2 of them now awaiting repair. Palliative operations were performed in nine patients before definitive surgery; four of these patients are long-term survivors. Prostaglandin E1 infusion improved oxygenation and relieved acidosis in four patients. It is concluded that most patients with d-transposition of the great arteries will survive to elective intraatrial baffle repair between 6 and 12 months without surgical palliation in spite of significant hypoxemia. Prostaglandin E1 infusion may be lifesaving and provide sufficient palliation in patients with persistent hypoxemia and acidosis after balloon atrial septostomy.

Female↗
PubMed1981

Laboratory and initial clinical studies of nifedipine, a calcium antagonist for improved myocardial preservation.

This report summarizes five years of laboratory investigations and the initial six-month clinical experience with a calcium antagonist, nifedipine, added to a cold hyperkalemic cardioplegic solution for enhancement of myocardial protection. Regional ischemia was created in 112 dogs and global ischemia in 98 dogs, under normothermic and two hyperthermic states. Control solutions, two clinical cardioplegic solutions, and nifedipine solutions were compared. Infusion of nifedipine during regional ischemia and reperfusion intervals resulted in a two-to-threefold reduction in injury volume and maintenance of normal left ventricular function in contrast infusion of nitroprusside. Nifedipine solutions (0.2 microgram/ml) provided superior preservation of left ventricular function in comparison to the two cardioplegic solutions after one hour of global ischemia at 37 degrees C and two hours at 18 C. In a clinical trial of nifedipine in cold potassium cardioplegia, 38 high risk patients with poor ventricular function have been treated; 22 of which were intensively studied serially with radionuclide ventriculography and pyrophosphate scans, myocardial isoenzyme determinations, 24 hour EKG recordings and intra- and postoperative hemodynamic studies. Of the 35 patients admitted to the intensive care unit (ICU), 33 have survived. Stroke work and cardiac indices return promptly to near normal levels after operation. The time-isoenzyme activity curves are low and radionuclide determined ejection fractions show no change for the study group. Death from acute postischemic cardiac failure did not occur in treated patients and the usage of intra-aortic balloon pump (IABP) has decreased threefold in comparison with 40 similar high risk patients treated concurrently with cardioplegic solution alone. It is concluded that nifedipine is a potent adjunct to cold hyperkalemic cardioplegic solution in high risk patients.

Adult↗
PubMed1980

Thymectomy for myasthenia gravis in the young adult. Long-term results.

An 8 year experience with a prospective treatment program for patients with myasthenia gravis is reviewed with particular focus on the results in patients less than 35 years of age. Twenty myasthenic young adults with an average age of 24 years and a duration of symptoms of 22 months, excluding two with the juvenile form, had thymectomy followed by short-term anticholinesterase and long-term prednisone therapy. All of the 18 patients with a short duration of symptoms are in markedly improved condition and 61% of them are in remission after a mean postoperative period of 32 months. The longest follow-up period is 7.3 years. Two patients have mild improvement. There was no correlation between thymic disease and clinical result. Complete en bloc extirpation of all thymic and adjacent tissue through a median sternotomy is advocated. The patients were treated postoperatively with prednisone, 100 mg/day, a regimen which gradually is changed to every other day medication and finally a gradual reduction of dosage. There have been no operative or late deaths and no serious complications of therapy. The effects have been long lasting, with not a single instance of significant recurrence of symptoms of myasthenia gravis 6 months after thymectomy.

Adolescent↗
PubMed1979

Use of saphenous vein to extend and relocate coronary arteries: clinical experience during extensive reconstructive operations of the aortic root.

Eight patients with advanced disease of the aortic root involving the origins of the coronary arteries have been operated on with resection of the entire aortic root including the ostia of the coronary arteries. Reconstruction was performed by insertion of a composite prosthesis; extension and relocation of the proximal portion of the coronary arteries was accomplished with saphenous vein segments. Two patients had infected aortic valve prostheses, three patients had acute aortic dissection and three had annuloaortic ectasia. Seven of eight patients survived the operation, the only operative death occurring in a patient submitted to an operation in a shock state following rupture of the aorta. There was, however, a high incidence of subsequent late deaths resulting from continued infection and from central circulatory failure. An analysis of this series of patients suggests the possibility that a reconstruction that relocates and extends the proximal portion of the coronary circulation may provide a total blood flow that is inadequate or inappropriate, and further suggests that the methods used in the reconstruction of the proximal circulation may be critical to the prevention of myocardial hypoperfusion.

Adult↗
PubMed1979

Comparison of bubble and membrane oxygenators in short and long perfusions.

Eighty patients had cardiopulmonary bypass (CPB), half having short (109 +/- 11 minutes) perfusions and half having long (188 +/- 14 min) perfusions. Twenty patients in each group were perfused with bubble oxygenators (Bentley, Harvey, or Galen) and 20 with membrane oxygenators (Modulung or Teflo). Hemodilution to a hematocrit value of 22.5% +/- 1.4% and hypothermia to 28 degrees +/- 2 degrees C were used in all patients. Complete hemograms, sequential multiple analyzer 18 tests, coagulation profiles, blood gases and pH, three immunoglobulins, and two complement fraction proteins were sampled as follows: three times before perfusion, one to ten times during perfusion, 1 hour immediately after perfusion, and 4, 24, and 48 hours postoperatively. Data in concentration terms were compared statistically and reported as mean and standard error for each subset. Additionally, rates of gain or loss were calculated in terms of quantity per liter of blood pumped per minute. During perfusion for both duration sets, use of a membrane oxygenator resulted in greater pump flows (4.55 +/- 0.15 L/min versus 3.75 +/- 0.11 L/min), lower total peripheral resistances (1,125 +/- 63 dynes.sec.cm-5 versus 1,652 +/- 115 dynes.sec.cm-5), and greater urinary outputs (9.4 +/- 1.1 ml/min versus 2.2 +/- 0.6 ml/min) than in the bubble oxygenator subsets. Comparisons of measured and calculated data in the immediate postperfusion interval showed no differences between bubble and membrane oxygenator subsets for short perfusions. In long perfusions, the membrane subset had lower plasma hemoglobin and white cell concentrations and generation rates, smaller (3 to 8 1/2 times) losses of IgG, IgM, C3 and shed blood necessitating less transfusion, and greater C4 losses. The membrane oxygenator systems used were more complex and costly and offered no advantages for short perfusion in adults. In anticipated long perfusions or where bleeding may be a problem, a membrane oxygenator appears more efficacious than bubble systems. For perfusions of less than 2 hours, membrane oxygenators had no biochemical or hematologic advantage over the bubble devices used in this study.

Blood Cell Count↗