Frank M. Midgley

Anticoagulation therapy in children with mechanical prosthetic cardiac valves

From 1980 through 1984, 28 children younger than 19 years (mean 7.9) underwent cardiac valve replacement with 30 mechanical prostheses. Patients were followed for a total of 471 months (mean 15.7) and received either warfarin (mean 0.16 mg/kg/day) or acetylsalicylic acid and dipyridamole (mean 6.1 and 1.9 mg/kg/day, respectively) as thromboembolism prophylaxis. The frequency and incidence of thromboembolism and hemorrhage were compared. Warfarin-treated patients were at increased risk of hemorrhage (5 of 20 [25%], or 22 per 100 patient-years, vs 0 of 10 [0%], or 0 per 100 patient-years, p less than 0.05). Three of the 5 hemorrhagic episodes were mild, and in no case was hemorrhage life-threatening. Patients who did not receive warfarin had a greater risk of thromboembolism (2 of 10 [20%], or 12 per 100 patient-years, vs 0 of 20 [0%], or 0 per 100 patient-years, p less than 0.05). Both episodes of thromboembolism were life-threatening and necessitated emergency valve replacement. Although warfarin is associated with greater risk of hemorrhage than is acetylsalicylic acid and dipyridamole, warfarin is better than antiplatelet drugs in thromboembolism prophylaxis and is indicated for anticoagulation therapy in children with mechanical cardiac prostheses.

Long-Term Results After Surgical Repair of Incomplete Endocardial Cushion Defects

Since 1964, 56 children (mean age, 6.7 years) underwent repair of incomplete endocardial cushion defects. Forty patients had isolated ostium primum defects. Additional congenital defects were present in 17 patients (30%). All patients underwent patch closure of the ostium primum defect and 47 of 56 patients (84%) underwent mitral valvuloplasty. Hospital mortality was 1.8% (one death). Arrhythmias developed in 7 other patients in the early postoperative period, of which six were transient and resolved completely. One patient required early pacemaker placement for complete heart block. Cumulative follow-up was 378 patient-years. There were three late deaths (5.7%), and additional operations were required in 12 patients (22.6%). Seven of these 12 patients required mitral valve replacement for severe mitral regurgitation. The mean interval between initial repair and mitral valve replacement was 4.2 years, with only three valves needing replacement within 12 months. There was a significant correlation between the severity of mitral regurgitation before initial repair and subsequent need for mitral valve replacement. Late onset atrial arrhythmias have developed in 6 patients. Current functional status has been evaluated in 50 of 52 surviving patients and 88.5% are in NYHA class I, with the remainder in class II.

A retrospective review of the role of transesophageal echocardiography in aortic and cardiac trauma in a level I Pediatric Trauma Center.

This study examined the role of transesophageal echocardiography in blunt aortic and cardiac trauma in a Pediatric Level I Trauma Center. In a > 5-year retrospective review, we identified 10 children with blunt cardiac (n = 4; tricuspid valve in two; mitral valve in one; aortic valve in one) and aortic (n = 6; aortic rupture in five, subintimal flap in one) trauma. Diagnosis of the cardiac injuries was made with transthoracic echocardiography, with transesophageal echocardiography providing additional anatomic detail and postoperative assessment in three of four children who required surgical intervention. Diagnosis of the aortic injuries was made with transesophageal echocardiography in five of six patients; one patient underwent aortography before transfer. Transesophageal echocardiography also identified depressed myocardial function in one child and aided in surgical management of the five aortic ruptures. In blunt chest trauma, transesophageal echocardiography provides accurate evaluation of cardiovascular structure and function and guides operative repair.

Role of echocardiography in the diagnosis and surgical management of accessory mitral valve tissue causing left ventricular outflow tract obstruction

We report an unusual case of left ventricular outflow tract obstruction caused by accessory mitral valve tissue. This case illustrates the importance of transthoracic echocardiography in preoperative evaluation and the usefulness of transesophageal echocardiography for intraoperative assessment. If the accessory mitral valve has no functional significance it may be surgically excised, thereby relieving the outflow tract obstruction.

Subclavian Steal Syndrome in the Pediatric Age Group

Four pediatric patients with subclavian steal syndrome (SSS) are described. One patient with congenital SSS had persistence of the lesion following surgical repair of coarctation of the aorta due to a gradient across a hypoplastic aortic arch. In 3 patients SSS developed on an acquired basis as a sequel to corrective operation, for coarctation in 1 patient, and interrupted aortic arch in 2 patients. Contributory factors included hypoplasia of the aortic arch, anatomical variation of the origin of the vertebral artery, and discrete recoarctation involving the ostium of the subclavian artery. Treatment was by vertebral artery ligation in 3 patients and by prosthetic patch arterioplasty in the patient with recoarctation. The 4 patients remain asymptomatic on follow-up of 16 to 25 months.

Small left atrium and change in contour of the ventricular septum in total anomalous pulmonary venous connection: A morphometric analysis of 22 infant hearts

Morphometric measurements of 22 hearts with total anomalous pulmonary venous connection (TAPVC) were compared with measurements of 8 matched control specimens without heart disease. Each of the TAPVC specimens had a shorter left atrium, smaller left atrial surface area and larger diameter of the fossa ovalis. In addition to increased length of the right ventricle and larger circumferences for tricuspid and pulmonary valve anuli, the left ventricular contour of the ventricular septum was flat or convex in 18 of the 22 hearts; the septum was significantly longer than normal in these specimens and wider at its midportion. Because mitral and aortic valve anuli were normal in circumference, the data suggest that left ventricular volume is not decreased despite change in ventricular shape.

Experience with Repair of Complete Atrioventricular Canal

Twenty-nine patients at out institution have undergone repair of complete atrioventricular canal since 1969. There were 3 operative and 5 late deaths, 4 of which were of infectious etiology. Age at operation ranged from 2 months to 12 years (mean, 50 months). Weight ranged from 3.6 kg to 30 kg (mean, 12 kg). Before repair, catheterization studies revealed pulmonary hypertension in all patients with unobstructed pulmonary arteries. Pulmonary to systemic flow ratio ranged from 1.5 to 10.6 (mean, 3.5). Pulmonary vascular resistance (PVR) ranged from 0.7 to 21.7 (mean, 5.3) Wood units/m2. At repair, 14 patients had Rastelli type A anatomy, 14 had type C, and 1 patient had a variant with crossing chordae and double-outlet right ventricle (DORV). Postoperative catheterization has been done in 16 patients 2 months to 8 years (mean, 30 months) after repair. One patient had residual ventricular shunting and later underwent successful repair. A 2-year-old patient had severe mitral regurgitation and died following mitral valve replacement. One patient required a permanent pacemaker. The 21 surviving patients have been followed from 7 months to 10 years 7 months and have excellent hemodynamic status. Long-term studies are needed to assess the ultimate effect on patients with high PVR.

Persistent left fifth aortic arch with complex coarctation.

Abstract Persistent fifth aortic arch is a rare anomaly, with only 22 cases reported. 1,2 Its recognition and successful management when associated with coarctation is even rarer. We present a child with persistent left fifth aortic arch and complex coarctation successfully diagnosed and repaired.

Focal cardiomyopathy and ectopic atrial tachycardia in Beckwith syndrome

Abstract The Beckwith syndrome was expanded in 1969 from Weidemanns report by Beckwith1 to include the presence of macroglossia, omphalocele, adrenal cytomegaly, gigantism and hyperplastic visceromegaly. Increased growth at a cellular and organ level is characteristic of the syndrome, as is increased oncogenic potential.2 Most neoplasms reported in the syndrome are intraabdominal; cardiac involvement is usually cardiomegaly.3 The child described herein is unique in 2 aspects: He has a focal cardiomyopathy that contains giant myocar dial cells in the absence of inflammatory changes, and the cardiomyopathic changes are located in regions of ectopic atrial tachycardia.

Repair of anomalous origin of the left coronary artery in the infant and small child

Anomalous origin of the left coronary artery from the pulmonary artery is associated with myocardial infarction, left ventricular dysfunction, mitral valve dysfunction and, occasionally, intracardiac congenital abnormalities. A technique that utilizes a flap of the anterior wall of the pulmonary artery to serve as a neocoronary artery to direct aortic flow from a created aortopulmonary window to the pulmonary artery orifice of the anomalous left coronary artery was used in five patients aged 2.5 months to 4.75 years. Two patients were less than 4 months of age at operation. There was one death 2 days after operation and one late death. The two youngest patients required mitral valve replacement. Two of the three surviving patients are well at follow-up at 7 to 44 months. One patient has been lost to follow-up study. One patient had postoperative catheterization which showed an intact repair. The pulmonary artery neocoronary procedure is applicable to infants and small patients with anomalous origin of the left coronary artery from the pulmonary artery.