Normal left ventricular function following pulmonary autograft replacement of the aortic valve in children

To assess growth potential and hemodynamic sequelae of pulmonary autograft valves implanted into aortic outflow tracts of children, we reviewed our experience with 37 patients (2-21 years) from August 1986 to December 1990. Twenty patients had predominantly aortic stenosis (AS), and 17 had aortic insufficiency (AI). Operative mortality was 3%. Two technical failures required reoperation. Of survivors, six (18%) have moderate AI. Pre- and postoperative echocardiograms were reviewed. The AS group showed increased left ventricular (LV) cavity size by greater than 1-year follow-up, and decreased LV wall and interventricular septal thickness. In the AI group, wall and septal thickness increased by 10 days and LV cavity decreased by 10 days, 60 days, and greater than 1 year. Root replacements (n = 14) showed mean increases of 4.3 mm and 5.3 mm, respectively, in diameters of the aortic annulus and aortic sinuses at greater than 1 year. Intraaortic implants increased 3.1 mm (annulus) and 3.9 mm (sinuses) at greater than 1 year. The pulmonary autograft procedure is safe, and successful implantation normalizes LV dimensions and function rapidly. The autograft valve shows evidence of growth at greater than 1 year postoperative. The pulmonary autograft may be the ideal valve replacement in children.

Delayed detection of coarctation in infancy: implications for timing of newborn follow-up

During a recent 5-year period, 74 patients younger than 6 months of age were diagnosed with coarctation of the aorta. Coarctation was correctly diagnosed in only 22% of patients prior to referral despite readily apparent femoral pulse abnormalities in 86%. Infants whose symptoms were detected between 5 and 14 days of age were significantly more ill than infants outside this age range and had a high mortality rate (25%). The number of associated cardiac defects was not related to the severity of clinical illness in this group, suggesting that closure of the ductus arteriosus is the primary determinate of disease severity. Observations in two patients suggested that a detectable pulse discrepancy occurs between 3 and 5 days postnatally. Upper extremity hypertension was found commonly in infants after 5 days of age despite the presence of congestive heart failure. Earlier detection of coarctation in the newborn requires a diligent cardiovascular and peripheral pulse examination between 3 and 7 days of life, upper extremity and lower extremity blood pressure measurement, and a high index of suspicion.

Correction of truncus arteriosus with truncal valvar stenosis or insufficiency using two homografts

Surgical correction of truncus arteriosus requires the creation of right ventricular to pulmonary artery continuity and closure of the ventricular septal defect. A variety of conduits have been used including valved and nonvalved. Despite a significant incidence of truncal valvar stenosis and insufficiency, this valve has seldom been replaced. We present 4 cases of truncus arteriosus with truncal valvar stenosis or insufficiency that were repaired using two valved homografts: one to create the pulmonary outflow tract and the other to replace the abnormal truncal valve. Two of these patients are doing well after 4 months. Another child survived the operation and did well for 2 months when she died suddenly. The last child died 14 hours postoperatively from low cardiac output syndrome secondary to diabetic hypertrophic cardiomyopathy. When truncal valvar abnormalities are present, the primary repair of truncus arteriosus in an infant should include replacement of the truncal valve. Total correction can be successfully achieved using two valved homografts, resulting in long-term palliation and freedom from thromboembolic events and the use of anticoagulants.

Alzheimer's disease amyloid peptide is encoded by two exons and shows similarity to soybean trypsin inhibitor

To better understand the processing of the Alzheimer disease amyloid precursor protein, we have cloned and sequenced that region of the human genome coding for the amyloid peptide. Two exons separated by a 6.2kb intron define this region. Characterization of the A4 peptide amino acid sequence shows similarity to the structure of soybean trypsin inhibitor (Kunitz). Our observation describes a different region of PreA4 than the previously characterized domain of larger amyloid precursor molecules PreA4 751 and 770(2). Moreover, the exon organization, Kunitz domain duplication and transmembrane location of A4 suggest that PreA4 is similar to growth factor precursors and thus may be processed similarly.

Elevated coronary sinus pressure does not alter myocardial blood flow or left ventricular contractile function in mature sheep. Implications after the Fontan operation

The hypothesis that elevation of coronary sinus pressure affects coronary blood flow and ventricular function was tested in this study of seven adult ewes placed under pentobarbital anesthesia. Coronary sinus pressure was elevated by partial balloon occlusion. Right atrial, left atrial, and aortic mean pressures and rate of rise of left ventricular pressure were measured. Coronary blood flow was determined with radioactive microspheres. Studies were performed at control and at moderate (15 to 20 mm Hg) and marked (30 to 35 mm Hg) elevation of coronary sinus mean pressures. Despite increase of coronary sinus pressure from a control value of 2 mm Hg +/- 1 to levels of 19 mm Hg +/- 1 and 34 mm Hg +/- 1, no significant changes were observed in right atrial, left atrial, or aortic mean pressure or rate of rise of left ventricular pressure. Both endocardial and epicardial blood flows were unaffected. The endocardial/epicardial flow ratio at moderate coronary sinus pressure elevation was significantly increased, which suggested local subendocardial vasodilation in the absence of changes in transmural perfusion. The findings suggest that isolated increase in coronary sinus pressure is not a major determinant of myocardial blood flow or ventricular performance in the normal ewe.

Restrictive interatrial communication in total anomalous pulmonary venous connection

Restriction to systemic blood flow at the atrial level in total anomalous pulmonary venous connection (TAPVC) may play a role in the early development of congestive heart failure in some patients. Over a 4-year period, 21 patients with TAPVC without extracardiac obstruction presented from 1 day to 10 months of age (mean 2.6 months). Of 21 patients, 17 (81%) presented after 1 month of age with moderate to severe congestive heart failure. In the first week after birth 4 patients presented with minimal symptoms of congestive heart failure. A small patent foramen ovale (3 mm or less in diameter) was found in 19 of 21 patients (90%) by 2-dimensional echocardiography or angiography. Balloon or blade and balloon atrial septostomy was performed in these 19 patients and resulted in significant decreases in mean right to left atrial pressure gradient (from 2.8 to 0.25 mm Hg, p less than 0.001), systolic pulmonary to femoral artery pressure ratio (from 0.80 to 0.60, p less than 0.001), and systemic arterial oxygen saturation (from 84% to 79%, p less than 0.01). One patient had nonfatal complications. Surgery was performed in 19 patients from 2 weeks to 29 months (mean 12 months) after catheterization, with 1 operative death (5% mortality). Four patients required early total correction because of persistent heart failure; 15 had elective surgical repair. One of 2 unoperated patients died of pneumonia at 2.5 years of age. A restrictive interatrial communication develops after the first month of extrauterine life in most patients with TAPVC. Atrial septostomy results in improved hemodynamic conditions and clinical palliation.(ABSTRACT TRUNCATED AT 250 WORDS)