Norman N. Musewe

Transcatheter occlusion of the persistently patent ductus arteriosus. Forty-month follow-up and prevalence of residual shunting.

BackgroundPercutaneous closure of the persistently patent ductus arteriosus with the Rashkind prosthesis is an established effective therapeutic modality, although some patients are left with residual shunting. To evaluate this, a retrospective study of the prevalence of persistent shunting over a 40-month period in the first 190 patients was undertaken. Methods and ResultsAll patients (male 45, female 145; mean age, 3.9 % 3.6 years; range, 5 months to 20 years) had serial clinical and color-flow echocardiographic follow-up at 6–12-month intervals (range, 6–40 months). Four patients required surgical removal of an embolized device, leaving a cohort of 186 patients in whom 196 procedures were performed, resulting in successful placement of 195 devices (43 17-mm [22%] and 152 12-mm [78% o]). Complications occurred in seven of 195 procedures (3.6%). Nine of 10 attempted reocclusions (all with 12-mm devices) were successful. The prevalence of residual shunting was 38% o at 1 year, 18% at 2 years, and 8% at 40 months. Patients with ductus measuring less than 4 mm had a higher success of initial occlusion. Thirty-four patients were left with residual shunting determined by color-flow Doppler study, but no anatomic or echocardiographic features were found predictive for residual shunting. All remain asymptomatic with 26 (76%) having no detectable murmur, two (6%) a continuous murmur, and six (18%) a systolic murmur. ConclusionsCatheter occlusion will obviate the need for surgery in the majority of patients presenting with persistently patent ductus arteriosus. Reocclusion has been found feasible in those with continuous murmurs (nine of nine) and should be offiered early because it is unlikely for spontaneous closure to occur in this group. It appears prudent to follow those with small residual shunting because further spontaneous closure can occur.

Echocardiographic follow-up of atrial septal defect after catheter closure by double-umbrella device.

BackgroundTranscatheter device occlusion of atrial septal defects is an attractive approach, but its efficacy and place in patient management remain to be determined. Methods and ResultsTo evaluate the medium-term results of atrial septal defect device occlusion and factors influencing residual shunting, transesophageal and transthoracic echocardiograms of 49 patients were reviewed. Transesophageal echocardiograms on 48 patients immediately following surgical closure revealed residual shunting in 2% compared with 91% after device occlusion; this proportion decreased to 53% after a mean follow-up of 10 months. The actuarial analysis suggests a progressive resolution of shunting with time. One patient had residual shunting by transesophageal echocardiography immediately after surgical closure compared with 29 after a mean follow-up of 10 months after device occlusion. Residual shunting was not influenced by (1) dimension, location, or position with relation to the device as assessed by transesophageal echocardiography; (2) location of the defect; or (3) device size relative to the stretched dimension of the defect. In 15 patients, a poor correlation existed between transesophageal and transthoracic echocardiographic findings. Variability in serial transthoracic echocardiographic findings was observed in 14. Right ventricular dimension, heart size, and presence of a murmur at follow-up did not correlate with the presence or size of residual shunting after device occlusion. ConclusionThese results suggest that ongoing spontaneous resolution of residual shunting occurs after device insertion. Factors related to the defect or device could not predict eventual resolution of residual shunting. Transthoracic echocardiography in the follow-up of these patients may not be reliable in determining presence of residual shunting.

Spectrum of cardiovascular anomalies in Williams-Beuren syndrome

SummaryThis study is presented to identify and characterize the spectrum of the cardiovascular anomalies in children presenting with Williams-Beuren syndrome and cardiovascular anomalies at The Hospital for Sick Children, Toronto from 1966 to 1988. Forty-nine children were diagnosed and followed. The female to male ratio was 1.2∶1. The age ranged from 1 month to 14 years at the time of diagnosis (mean 39 months), and follow-up periods were from 9 months to 20 years (mean 10 years). All patients having the typical features were also evaluated by geneticsts. Based on cardiovascular findings four groups were identified. Group 1 had isolated supravalvular aortic stenosis (SVAS) (28 patients). There was follow-up in 24 of these children. Six had worsening of supravalvular narrowing and underwent surgery. One showed an increased gradient from 10–40 mmHg during 7 years. Seventeen had mild narrowing and showed no progression over a period of 75 months. Group 2 had isolated pulmonary artery branch stenosis (8 patients). Seven had mild narrowing which remained unchanged over a mean period of 16 months and one underwent surgery. Group 3 had combined lesions (11 patients). Six showed increased left-side narrowing, while right-side obstruction remained static or improved. Five showed improvement in narrowing in both outflow tracts. Five underwent surgery. Additional cardiovascular anomalies included peripheral artery stenosis in two patients, coronary artery abnormalities in three, mitral valve prolapse in three, and coarctation of the aorta in two. Group 4 had isolated lesions. One patient had isolated coarctation of the aorta and one isolated mitral prolapse. In conclusion, supravalvular aortic stenosis was the most common lesion, whereas pulmonary artery stenosis improved in most patients. The role of coronary artery abnormalities has yet to be defined.

Doppler echocardiographic measurement of pulmonary artery pressure from ductal Doppler velocities in the newborn

The ductal flow velocities in 37 newborns (group 1: persistent pulmonary hypertension [n = 16], transient tachypnea [n = 3], other [n = 2]; group 2: respiratory distress syndrome [n = 16]) were prospectively evaluated by Doppler ultrasound for the purpose of deriving systolic pulmonary artery pressures. Maximal tricuspid regurgitant Doppler velocity in 21 of these patients was used to validate the pulmonary artery pressures derived from ductal flow velocities. There was a significant linear correlation between tricuspid regurgitant Doppler velocity and pulmonary artery systolic pressure derived from ductal Doppler velocities in patients with unidirectional (pure left to right or pure right to left) ductal shunting (p less than 0.001, r = 0.95, SEE 8) and in those with bidirectional shunting (p less than 0.001, r = 0.95, SEE 4.5). Systolic pulmonary artery pressure in group 1 (67 +/- 13 mm Hg) was significantly higher than that in group 2 (39 +/- 10 mm Hg) (p less than 0.001). In those with bidirectional shunting, duration of right to left shunting less than 60% of systole was found when pulmonary artery pressure was systemic or less, whereas duration greater than or equal to 60% was associated with suprasystemic pulmonary artery pressures. Serial changes in pulmonary artery systolic pressure, reflected by changes in ductal Doppler velocities, correlated with clinical status in persistent pulmonary hypertension of the newborn. Persistently suprasystemic pulmonary artery pressure was associated with death in five group 1 patients. It is concluded that ductal Doppler velocities can be reliably utilized to monitor the course of pulmonary artery systolic pressures in newborns.

Ambulatory blood pressure monitoring and left ventricular mass and function after successful surgical repair of coarctation of the aorta

Late cardiovascular morbidity and mortality remain significant despite apparently successful surgical repair of aortic coarctation. Alterations in cardiac function have been reported in normotensive patients who have had successful repair, the reasons for which remain unclear. This study addresses the relation between ambulatory blood pressure measurements and alterations in left ventricular performance in 20 patients with normotension at rest after successful repair of aortic coarctation. Exercise testing, ambulatory blood pressure monitoring and two-dimensional echocardiographic studies in 13 boys and 7 girls (mean age 14.2 +/- 2.31 and 14.7 +/- 3 years, respectively) who had no evidence of recoarctation were compared with the findings in 20 matched control subjects. No difference was found in systolic blood pressure at rest or peak exercise between patients and control subjects. Male patients developed a significant arm/leg gradient at peak exercise. Systolic ambulatory blood pressure was higher throughout the day in the male group. In the female group, systolic blood pressure was higher only during sleep. No difference was found in diastolic blood pressure or heart rate. The transverse aortic arch was smaller and the left ventricular mass greater in all patients. The relation of wall stress to rate-corrected velocity of shortening was 2 SD above normal in 8 of the 20 patients, suggesting that some have enhanced contractility. The E/A ratio on the atrial echocardiogram was significantly reduced in the patient group. Successfully treated patients who are normotensive at rest after operation are still at risk for developing end organ damage, which is probably explained by incipient mild hypertension documented by ambulatory blood pressure monitoring.

Two-dimensional echocardiographic and color flow Doppler evaluation of ductal occlusion with the Rashkind prosthesis.

To evaluate the results of ductal occlusion with the Rashkind prosthesis, 78 children (group 1, 19 boys and 59 girls; mean age at occlusion, 4.5 +/- 4.0 years) with isolated patent ductus arteriosus (n = 73) or in association with other lesions (n = 5) were evaluated by pulsed and color flow Doppler 9 +/- 7 months (range, 2-26 months) after occlusion. Thirty children who had undergone patent ductus arteriosus ligation (group 2, 9 boys and 21 girls; mean age at study, 5.7 +/- 4.9 years; mean follow-up after ligation, 44 +/- 58 months) were evaluated in the same way. The prevalence of residual ductal shunting and the main pulmonary arterial flow patterns were recorded. Residual ductal shunting in group 1 was 38% on day 1, decreasing slowly to 31% at 3 months, 27% at 6 months, and 19.7% at 1 year or more due to further spontaneous shunt resolution. The residual shunting rate in group 2 (6%) was significantly lower than that at 1 year or more in group 1 (p less than 0.001). Successful reocclusion in 5 of 6 in a subset of patients in group 1 followed for 1 year or less reduced further the prevalence of residual shunting. Residual shunting after patent ductus arteriosus occlusion is more common than after ligation, but continues to decrease during follow-up.

Echocardiographic evaluation of the spectrum of cardiac anomalies associated with trisomy 13 and trisomy 18

To investigate the role that cardiac anomalies play in the early death frequently seen in the trisomy 13 and the trisomy 18 syndromes, two-dimensional and Doppler echocardiograms from 31 newborn infants with cytogenetic confirmation of these syndromes seen at one institution over a 4.5 year period (1983 to 1988) were reviewed. The mean age at echocardiography was 1.5 days, and the median age at death was 14 days. Significant cyanosis was present in 58%. Cardiac anomalies that would be considered lethal within the neonatal period were present in only 19% of patients. The most common lesions were atrial septal defect (81%), ventricular septal defect (61%) and patent ductus arteriosus (85%). Most ventricular septal defects and patent ductus arteriosus were large. Valvular dysplasia of one or more valves, graded as mild in most cases, was found in 68%, but was not associated with Doppler evidence of significant regurgitation or stenosis in any subject. Of the four valves, the pulmonary valve, followed by the tricuspid valve, was the most commonly dysplastic. Doppler evidence suggestive of elevated pulmonary artery pressure (low velocity bidirectional flow across the ventricular septal defect and patent ductus arteriosus), although expected, was accompanied by greater than normal mean right ventricular cavity and free wall dimensions in these patients. Thus, although the cardiac anomalies most frequently encountered in trisomy 13 and trisomy 18 are nonlethal, the combined findings of frequent cyanosis and increased right ventricular dimensions suggest that other factors such as pulmonary hypertension, perhaps related to maldevelopment of the pulmonary vasculature, may contribute to early death in some of these infants.

Extent of myocardial noncompaction: comparison between MRI and echocardiographic evaluation

Background: Noncompaction of the left ventricular myocardium is an important cause of cardiomyopathy. There is no clear consensus about its diagnostic criteria or the diagnostic test of choice. MRI is increasingly used in the pediatric cardiac field because of its superior and objective image quality. Objective: To compare the echocardiographic and MRI findings in four patients with recently diagnosed ventricular noncompaction. Materials and methods: We compared the extent of myocardial involvement shown at MRI and echocardiography in four individuals, two patients with echocardiographic diagnosis of left ventricular noncompaction, and two family members of one of the patients. Results: In all patients, MRI showed wider area of involvement than echocardiography. A definite diagnosis was entertained in only two patients by echocardiography but in all by MRI. Cine imaging was diagnostic of the disease in all patients. Black-blood pool imaging with double-inversion recovery sequence also helped to visualize the abnormal areas by showing slow flow artifacts in the four- and two-chamber images. Conclusion: MRI provided better delineation of the extent of the abnormal trabeculation in patients with noncompaction of the left ventricular myocardium. It was particularly useful when the myocardial involvement was subtle, as in the asymptomatic family members.

Validation of Doppler-derived pulmonary arterial pressure in patients with ductus arteriosus under different hemodynamic states.

Twenty-nine patients with a patent ductus arteriosus (PDA) in isolation (n = 17) or in combination with other lesions (n = 12) underwent simultaneous hemodynamic assessment and evaluation of PDA flow velocity by the Doppler method. The accuracy with which Doppler velocity across the PDA predicted pulmonary arterial pressure and the influence of PDA size and shape on the Doppler velocity-pressure relationship were examined. Seventy percent had a cone-shaped PDA (narrowest at the pulmonary artery end), and the remainder were tubular. Narrowest PDA diameter ranged from 1.5 to 9 mm (mean 3.5 mm). Peak systolic and mean pulmonary arterial pressure ranged from 10 to 116 and 8 to 72 mm Hg, respectively. Twenty-one patients (group 1) had left-to-right shunting only. The following variables showed significant correlation in this group: peak instantaneous systolic aortic-to-main pulmonary arterial (MPA) pressure gradient and maximum Doppler velocity across the PDA (slope = 1.03, SEE = 13 mm Hg, r = .94, p less than .001), mean aortic-to-MPA pressure gradient and mean Doppler velocity (slope = 1.06, SEE = 10 mm Hg, r = .95, p less than .001), and end diastolic aortic-to-MPA pressure gradient and minimum Doppler velocity (slope = 1.12, SEE = 8 mm Hg, r = .96, p less than .001). Eight patients (group 2) had bidirectional shunting. In this group peak instantaneous aortic-to-MPA pressure gradient significantly correlated with maximum Doppler velocity measured from the left-to-right shunt (slope = .70, SEE = 2 mm Hg, r = .92, p less than .002) and mean pressure gradient correlated with mean Doppler velocity (slope = .83, SEE = 3 mm Hg, r = .78, p less than .003). Right-to-left Doppler velocities showed no correlation with pressures. In six patients with pulmonary hypertension Doppler velocity changes accurately predicted the effect of pulmonary vasodilation on pulmonary arterial pressure. Doppler velocity of PDA flow reliably predicts pulmonary arterial pressure over a wide range of pressures and PDA shapes and sizes.

Echocardiographic and Doppler evaluation of the aortic arch and brachiocephalic vessels in cerebral and systemic arteriovenous fistulas

Congenital arteriovenous fistulas presenting in the newborn period pose difficult diagnostic problems and simulate structural heart disease. Angiocardiography, when performed, demonstrates enlarged brachiocephalic vessels and rapid cerebral venous return. The value of echocardiographic imaging and measurement of the aortic arch and brachiocephalic vessels, and evaluation of the Doppler flow profile in these vessels as a means of making a rapid diagnosis of cerebral or thoracic arteriovenous fistula, was therefore assessed in 10 infants with these diagnoses seen over a 4 year period (1983 to 1987). Twenty-nine infants (median age 6 weeks) undergoing two-dimensional echocardiography but with no significant lesions were prospectively selected as controls. Nine of the 10 patients had congestive heart failure at presentation (mean age 2 days). A cranial bruit was heard in three and arteriovenous fistula was suspected in five patients. Aortic arch segments and brachiocephalic vessel dimensions expressed as ratios of the abdominal aorta showed significantly larger values in patients for the ascending aorta (p = 0.01), innominate artery (p less than 0.001), right and left subclavian arteries (p less than 0.001) and left common carotid artery (p less than 0.05). The thoracic descending aorta was, however, significantly smaller in patients (p less than 0.002). Retrograde diastolic Doppler flow in the descending aorta proximal to the ductus arteriosus and anterograde diastolic flow with a mean spectral flow-time integral 27% of systolic were present in patients only, whereas Doppler diastolic flow in brachiocephalic vessels, present in 5 of 29 control infants, was less than 15% of systolic flow and not accompanied by dilation of these vessels.(ABSTRACT TRUNCATED AT 250 WORDS)