Biomedical subjects

Mark D Rodefeld

Publications and source records attributed to Mark D Rodefeld.

22 records · Page 2Linked to original sources

PubMed2003

Cavopulmonary assist: circulatory support for the univentricular Fontan circulation.

BACKGROUND: Following Fontan palliation, the univentricular circulation is notable for coexisting systemic venous hypertension and pulmonary arterial hypotension. Assisted cavopulmonary blood flow to overcome this pressure gradient would restore the circulation to one more closely resembling normal two-ventricle physiology. We hypothesized that mechanical augmentation of cavopulmonary blood flow would provide physiologic stability in a model of cavopulmonary diversion and univentricular circulation. METHODS: Yearling sheep (n = 13, mean weight 56.5 kg) underwent total cavopulmonary diversion on cardiopulmonary bypass. The superior and inferior vena cavae were anastomosed directly to the right pulmonary artery. Axial flow pumps were positioned within both vena cavae to assist blood flow from the systemic venous circulation into the pulmonary vasculature. Baseline ventilation was resumed, cardiopulmonary bypass was weaned, and pump support was titrated to obtain normal physiologic measurement. Cardiopulmonary data were collected for 6 hours. RESULTS: All animals demonstrated hemodynamic stability without need for volume loading, inotropic support, or pulmonary vasodilator therapy. Cardiac output, pulmonary vascular resistance, pulmonary arterial pressure, inferior vena caval pressure, and arterial pCO(2) and pO(2) values 6 hours after intervention were similar to baseline values. Arterial lactate levels steadily decreased throughout the cavopulmonary assist period. CONCLUSIONS: Cavopulmonary assist with a percutaneous pump provides physiologic stability in a model of total cavopulmonary diversion and univentricular Fontan circulation without altering regional volume distribution or cardiac output. This mode of circulatory support may have potential to benefit patients with marginal Fontan hemodynamics in both the early and late time periods.

Animals↗

PubMed2003

Surgery for aortic stenosis in children: a 40-year experience.

BACKGROUND: Aortic stenosis (AS) is encountered in approximately 5% of children with heart disease. The indications for surgery and the surgical techniques for AS are well established. This report focuses on the early and long-term outcomes in children with AS over a 40-year period. METHODS: Included in this study were 508 patients ranging in ages from 1 day to 19 years, who were operated on for AS between 1960 and 2002. Eighty-one percent (414 of 508) of the patients had left ventricular outflow tract obstruction (LVOTO) at a single level: 40 supravalvar, 242 valvar (critical AS in 85 neonates and young infants and in 157 older children), and 132 subvalvar. Nineteen percent (94 of 508) of the patients had LVOTO at more than one level. Associated congenital cardiac defects were found in 32% of the patients. RESULTS: The overall hospital mortality rate was 8% (40/508) with neonates with critical AS having the highest mortality (33%). The late mortality was 4% for the entire group. Follow-up was 95% complete. The mean follow-up was 8.5 +/- 7.1 years. In the subgroup with multilevel LVOTO (n = 94), the average intraoperative peak systolic left ventricular-aortic gradient decreased from 80 to 22 mm Hg after repair but increased progressively to 74 +/- 36 mm Hg (p < 0.05) before reintervention was required. One hundred twenty-one patients (24%) underwent 151 reoperations for recurrent or residual LVOTO or aortic regurgitation. Actuarial curves predict a 20-year survival of 88% and 62% freedom from reoperation for all patients with AS. Symptomatic improvement in survivors was excellent (90% New York Heart Association class I). CONCLUSIONS: Surgical relief of LVOTO in infants and children can be accomplished with low mortality and morbidity. Neonates with critical AS have significantly higher mortality and morbidity due to their complex anatomy and their critical presentation that affects outcome. Aortic valvotomy delays valve replacement in a significant percentage of children. The Ross procedure and mechanical aortic valve replacements have had a low mortality and morbidity in our series. Valve replacement will eventually be required in most children presenting with valvar AS and multilevel LVOTO while repair of discrete subaortic stenosis and supravalvar AS may not require reoperation in most patients. Children with LVOTO should have lifetime follow-up.

Adolescent↗

PubMed2002

Neonatal truncus arteriosus repair: surgical techniques and clinical management.

Truncus arteriosus is now ideally repaired in the neonatal period with low morbidity and mortality. Published reports have documented mortality rates in the range of 4% to 5% with mean age at repair as low as 11 days. The physiologic basis for improved outcomes with earlier repair is the avoidance of damaging sequelae of pulmonary overcirculation and heart failure. Data show that baseline mean pulmonary artery pressure is lower in infants undergoing earlier repair. Improved operative outcomes also have been achieved with aggressive truncal valve repair versus replacement in the presence of truncal valve dysfunction, right ventricular outflow tract reconstructive techniques that are patient anatomy-specific, and use of regional perfusion techniques for repair of associated interrupted aortic arch. In addition, a heightened awareness of anomalies of coronary artery ostial location, number, angle of takeoff, and degree of patency can result in avoidance of inadvertent injury to the artery and associated myocardial insult.

Cardiac Surgical Procedures↗

PubMed2002

Surgical creation of aortopulmonary window in selected patients with pulmonary atresia with poorly developed aortopulmonary collaterals and hypoplastic pulmonary arteries.

OBJECTIVE: The morphologic characteristics of the pulmonary circulation vary widely in patients with pulmonary atresia, ventricular septal defect, and major aortopulmonary collaterals. Although we favor single-stage unifocalization and complete repair as the procedure of choice, a subgroup of patients who meet specific criteria have been treated with initial surgical creation of an aortopulmonary window. METHODS: Eighteen patients who were considered unsuitable candidates for single-stage repair underwent surgical creation of an aortopulmonary window. Selection criteria included the following: (1) presence of centrally confluent true pulmonary arteries 1.0 to 2.5 mm in diameter, with a well-developed peripheral arborization pattern; (2) multiple small aortopulmonary collateral vessels, most of which communicated with the true pulmonary arterial system; and (3) the presence of marked cyanosis. RESULTS: There were no early deaths, and the 2 late deaths were both unrelated to the procedure. Follow-up angiography (n = 17) demonstrated good growth of true pulmonary arteries in 15 of 17 cases (88%). Mean pulmonary artery diameter increased from 1.76 mm to 3.45 mm. Subsequent operations have been performed in 15 of 18 cases (83%). Intracardiac repair with or without additional unifocalization was achieved in 8 of these 15 (53%). Seven patients (47%) have undergone staged unifocalization as the next procedure; of these, 3 were able to have intracardiac repair. Thus 11 of the 15 patients who have undergone second operations (73%) have had complete intracardiac repair. CONCLUSIONS: The initial surgical creation of an aortopulmonary window in carefully selected patients can increase the size of the true pulmonary arteries, making these patients better candidates for eventual intracardiac repair. The procedure should be avoided in patients with pulmonary overcirculation, a predominance of isolated supply collaterals, or true pulmonary arteries larger than 2.5 mm in diameter, and it is not applicable without a true pulmonary artery central confluence.

Aorta↗