Aortic aneurysm after patch aortoplasty for coarctation: analysis of patch size and wall growth.

Aortic aneurysm may develop after surgery for coarctation of aorta especially patch aortoplasty. The size of patch and of adjacent native aortic wall was analyzed to determine whether aortic dilatation represents a true aneurysm. Electron beam tomography (EBT) was done on 19 patients, three months to 17.5 years after patch aortoplasty. Tomograms of aorta were obtained in 6-mm slices, and maximal cross-sectional area was digitized to obtain: total circumference (Ct), patch component (Cp), and aortic wall component (Cw). Ct, Cp, and Cw were normalized to the circumference of distal aorta (Cda) as: isthmus/distal aorta (Ct/Cda), patch segment/distal aorta (Cp/Cda), wall segment/distal aorta (Cw/Cda). Ct/Cda ranged from 109% to 260%. In 12 patients (group A), it varied from 168% to 260%; and in seven (group B), 109% to 133%. There was strong correlation (r = 0.92) between Ct/Cda and Cp/Cda. Ct/Cda, Cp/Cda, and Cp/Cw were higher in group A than B (p <0.001) but Cw/Cda did not differ. Cw/Cda was greater than the coarctation/distal aorta diameter ratios of preoperative angiograms, consistent with accelerated aortic wall growth postsurgery. No definite aneurysm was seen. Localized dilatation of aorta following patch aortoplasty in children is primarily due to a large synthetic patch and, partly, to increased aortic wall growth. Serial EBT or magnetic resonance imaging is indicated to monitor aortic wall growth and occurrence of aneurysm.

Use of an optical fiber scope to confirm endotracheal tube placement in pediatric patients.

OBJECTIVE: To determine the efficacy of a portable optical fiber scope to confirm endotracheal tube (ETT) placement. DESIGN: A prospective, nonrandomized, blinded study. SETTING: Pediatric intensive care unit in a children's hospital. PATIENTS: Thirty mechanically ventilated patients with an ETT in place. INTERVENTIONS: Patients entered into the study underwent ETT placement determination by chest roentgenogram (CXR) and by the optical fiber scope. MEASUREMENTS AND MAIN RESULTS: Thirty patients were entered into the study, for a total of 46 measurements (n = 46). ETT size ranged from 3.0 to 6.0 mm internal diameter. Distance from the ETT and the carina was determined by the scope and compared with the distance measured on the CXR. No statistical difference was found between the two methods. None of the patients experienced clinically significant side effects from the procedure. On three occasions, the presence of secretions in the ETT did not allow for the visualization of the carina by the scope. CONCLUSION: The use of a flexible optical fiber scope is an accurate, fast, and practical method to determine ETT placement in pediatric patients on mechanical ventilation.

Surgical techniques in partial anomalous pulmonary veins to the superior vena cava.

Over a 12-year period, 40 patients underwent repair of partial anomalous pulmonary veins (PAPV) draining to the superior vena cava (SVC) proximal to the sinus node. Mean age was 6 +/- 2 years. In all patients, the SVC was cannulated superior to the PAPV, which were baffled with pericardium to left atrium. Six patients had associated defects repaired. In 18 patients (group I), an incision was made at the crest of the right atrial appendage (RAA) and extended upward through the sinus node and to the SVC. After rerouting of the PAPV, the SVC was enlarged using the RAA (atriocavoplasty). In 17 patients (group II), rerouting of the PAPV was accomplished through a right atriotomy. Superior vena caval enlargement was not done. Drainage of the PAPV was close to the right atrium in 14 patients (low) and to the azygos vein (high) in 3. In 5 patients (group III), an incision was made on the SVC and RAA sparing the sinus node. After rerouting of the PAPV, the RAA was anastomosed to the SVC (end to side), providing another outlet for SVC flow. There was no early or late death. Two patients (10%) in group I had late sinus bradycardia. Obstruction of the SVC and PAPV developed in 1 patient in group II with high drainage. Intermittent complete heart block developed in 1 patient in group III who also had ventricular septal defect repair. We conclude that atriocavoplasty is effective for rerouting of the PAPV and enlarging the SVC, but may predispose to sinus node disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Advantages of early relief of subaortic stenosis in single ventricle equivalents.

Thirteen patients with single ventricle equivalents and subaortic stenosis underwent relief of the stenosis and subsequent Fontan operation. Nine patients, group 1, had the obstruction relieved at 3.6 +/- 1.6 years of age whenever the pressure gradient became apparent. Four patients, group 2, had the subaortic stenosis operated on at the neonatal period, 10.5 +/- 10 days old, before hemodynamic evidence of obstruction. Preoperative pressure gradient across the outflow tract was 44.2 +/- 4.7 mm Hg in group 1 versus 4.7 +/- 5 mm Hg in group 2 (p = 0.002). Ventricular muscle mass was 186% +/- 18% in group 1 versus 114% +/- 5% of normal in group 2 (p = 0.0001), and mass/volume ratio was 1.12 +/- 0.62 in group 1 versus 0.62 +/- 0.16 in group 2 (p = 0.003). Relief of subaortic stenosis was achieved by proximal pulmonary artery to ascending aorta or aortic arch anastomosis and by systemic to distal pulmonary artery shunt. There was no hospital mortality or complication related to the procedure. At evaluation before Fontan operation, 4.3 +/- 1.6 years after relief of subaortic stenosis in group 1 and 3.2 +/- 0.9 years in group 2, the pressure gradient across the ventricular outflow tract was 4 +/- 3 mm Hg in group 1 versus 3 +/- 2 mm Hg in group 2 (p = not significant), ventricular muscle mass was 184% +/- 31% in group 1 versus 114% +/- 5% of normal in group 2 (p = 0.003), and the mass/volume ratio was 1.17 +/- 0.2 in group 1 versus 0.62 +/- 0.2 in group 2 (p = 0.003).(ABSTRACT TRUNCATED AT 250 WORDS)

Extended aortic valvuloplasty: a new approach for the management of congenital valvar aortic stenosis.

A new technique for the treatment of congenital valvar aortic stenosis is described. It consists of augmenting the aortic cusp by extending the commissurotomy incision into the aortic wall around the leaflet insertion, mobilizing the valve cusp attachment at the commissures, and freeing the aortic insertion of the rudimentary commissure. The results of standard valvotomy performed on 48 patients (group 1) were compared with those of the new extended valvuloplasty carried out on 16 patients (group 2). The two groups were comparable in age at operation (2.7 +/- 2.1 years for group 1 versus 2.1 +/- 1.7 years for group 2; p = not significant) and in preoperative pressure gradient (58 +/- 25 mm Hg for group 1 versus 61 +/- 36 mm Hg for group 2; p = not significant). There was no operative mortality in either group. Follow-up is available on all patients, with a mean of 4.3 +/- 2.6 years for group 1 versus 1.7 +/- 0.5 years for group 2 (p = 0.05). There was one late death in group 1. Postoperative gradient was 47 +/- 13 mm Hg in group 1 versus 19 +/- 13 mm Hg in group 2 (p = 0.05). Moderate or severe regurgitation was present in 18 patients (38%) in group 1 and 2 patients (13%) in group 2 (p = not significant). Reoperation was needed in 8 patients (17%) in group 1 versus 2 patients (13%) in group 2 (p = not significant). The described valvuloplasty procedure addresses the unique pathological features of valvar aortic stenosis and provides better relief of the obstruction than the presently available techniques. Longer follow-up is needed to determine the late results of this approach.

Tilt test for diagnosis of unexplained syncope in pediatric patients.

Thirty-five teenage patients with a history of presyncope or syncope underwent a passive head-up tilting to reproduce symptoms of syncope. If tilting alone did not induce syncope, isoproterenol infusion was given to increase heart rate to 150 to 160 beats per minute. In 80% of patients with a history of syncope, identical symptoms could be reproduced during tilting: an abrupt fall in blood pressure combined with profound nodal bradycardia, ranging from 32 to 86 beats per minute. These symptoms were quickly reversed by returning the patient to the supine position. For patients with frequent occurrences of syncope, especially when there was a history of trauma sustained during these episodes, a therapeutic regimen of either beta blockers or 9 alpha-fluorocortisol was begun. The mechanisms of this common cause of syncope in childhood is neurocardiogenic in response to venous pooling and catecholamine-induced tachycardia. The tilt test is an excellent and cost-effective test for the workup of unexplained syncope in childhood.

Choreoathetosis after deep hypothermia without circulatory arrest.

In 8 of 758 patients undergoing an intracardiac operation under cardiopulmonary bypass and hypothermia, choreoathetosis developed 3 to 7 days postoperatively. Before the onset of choreoathetosis, varying degrees of neurological dysfunction were noted. Electroencephalography and neuroimaging failed to detect any responsible functional or structural changes. Six patients are alive 1 to 3 years postoperatively, and their condition is improving. Two patients died of aspiration or sepsis. All patients were grouped based on factors identified as being possibly causative: depth of hypothermia, cooling time, flow rate, and repeated hypothermia. The incidence of choreoathetosis was significantly different in group A (rectal temperature greater than 25 degrees C) compared with group B (rectal temperature less than or equal to 25 degrees C) (0/295 versus 8/463; p = 0.02). Based on cooling time, the incidence of choreoathetosis was significantly different in group B1 (cooling time less than 1 hour) compared with group B2 (cooling time greater than or equal to 1 hour) (1/220 versus 7/243; p = 0.05). Based on flow rate during cooling, group B2 was further divided into the low-flow group (less than 1,500 mL.min-1.m-2) and the high-flow group (greater than or equal to 1,500 mL.min-1.m-2). Although not significant, the incidence of choreoathetosis was higher in the high-flow group (6/153 versus 1/90; p = 0.22). In group B patients having reoperation, the incidence of choreoathetosis was higher than in patients operated on for the first time (5/54 versus 3/409; p less than or equal to 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Premortem assessment of myocardial area at risk with the use of intracoronary technetium macroaggregated albumin and gated nuclear imaging.

The purpose of this study was to develop a clinically applicable system for quantifying premortem myocardial area at risk. Coronary artery occlusion was performed in 18 closed-chest dogs (11 left anterior descending and seven circumflex). 99mTc (15 mCi)-labeled macroaggregated albumin was then injected through an angiographic catheter into the left main coronary artery. Gated nuclear images were obtained in the left anterior oblique view in dogs with left anterior descending occlusions and in right anterior oblique views in dogs with circumflex artery occlusions. The corresponding end-diastolic images were analyzed. The percent area at risk was determined as the planimetric ratio between the hypoperfused area and that of the total left ventricular myocardium. At the completion of the study the heart was excised and the autoradiographic area at risk for the left ventricle was determined. The theoretic advantage of the use of gated acquisition for determination of area at risk over the use of nongated acquisition was assessed. For each study a time-integrated nongated image was produced by summating all frames of the gated study. The area at risk on this composite image was analyzed in the same manner as for the gated study and compared with the postmortem area at risk. Studies in five control dogs in which concomitant left atrial and intracoronary injection of different radioactive-labeled macroaggregates were used revealed no false-positive defects and similar and relatively homogenous radionuclide distribution. Postmortem autoradiographic area at risk ranged from 3.8% to 36.3% of the left ventricular mass. End-diastolic areas at risk in vivo correlated well with those determined by the postmortem autoradiographic method (r = .95, y = 0.86x + 2.7). The regression equations relating interobserver and intraobserver variance for analysis of the end-diastolic image areas at risk were small (r = .98, y = 1.06x - 0.66 and r = .96, y = 1.06x - 0.50, respectively). The interobserver and intraobserver differences for determinations of autoradiographic area at risk were represented by r = .99, y = 1.04x - 0.54 and r = .95, y = 0.88x + 2.79. Finally, comparison of the area at risk in vivo for the nongated image with the postmortem area at risk yielded a correlation of r = .79, y = 0.80x - 2.2. Nongated imaging was less sensitive and accurate than gated imaging and resulted in three false-negative studies, as well as a poorer correlation with results of postmortem autoradiography.(ABSTRACT TRUNCATED AT 400 WORDS)