Assessment of the geometric profile of the Amplatzer and Cardioseal septal occluders by three dimensional echocardiography

OBJECTIVE—To apply three dimensional echocardiography to describe the geometric profile of the Amplatzer and Cardioseal occluders after deployment for closure of atrial septal defect.
METHODS—20 patients (mean (SD) age, 14 (5) years) were enrolled for transcatheter closure of a secundum atrial septal defect with the Amplatzer occluder (10) or with the Cardioseal occluder (10). The two populations were matched for the stretched diameter of the defect (mean 18 (6) mm). The profile of the two occluders was examined.
RESULTS—Transoesophageal echocardiography did not show any residual shunts after Amplatzer occluder deployment, whereas three patients had a small residual leak after Cardioseal deployment. One patient had transient atrioventricular block with the Amplatzer device. The mean surface area of the Amplatzer occluder was 6.9 (2) cm(2), and that of the Cardioseal device 5.4 (3) cm(2) (p = 0.03). The mean volume of the Amplatzer occluder was 9.2( )(1) cm(3), while that of the Cardioseal occluder was 3.5 (1) cm(3) (p < 0.0001). From the three dimensional views, the Cardioseal occluder looked like a flat square after deployment whereas the Amplatzer occluder took up a ball shape in the atrial cavity.
CONCLUSIONS—Three dimensional views by multiplane transoesophageal echocardiography allow a realistic in vivo description of atrial septal occluders. The Amplatzer occluder, with its high geometric profile, allows complete closure of large atrial septal defects but with some risk of mechanical complications. Use of the Cardioseal device, with its small surface coverage and high residual shunt rate, should be limited to transcatheter closure of a patent foramen ovale or small atrial septal defects.


Keywords: atrial septal occluder; three dimensional echocardiograph

Mechanical properties of the common carotid artery in Williams syndrome

OBJECTIVE—To determine whether arterial wall hypertrophy in elastic arteries was associated with alteration in their mechanical properties in young patients with Williams syndrome.
METHODS—Arterial pressure and intima-media thickness, cross sectional compliance, distensibility, circumferential wall stress, and incremental elastic modulus of the common carotid artery were measured non-invasively in 21 Williams patients (mean (SD) age 8.5 (4) years) and 21 children of similar age.
RESULTS—Systolic and diastolic blood pressures were higher in Williams patients (125/66 v 113/60 mm Hg, p < 0.05). The mean (SD) intima-media thickness was increased in Williams patients, at 0.6 (0.07) v 0.5 (0.03) mm (p < 0.001). Normotensive Williams patients had a lower circumferential wall stress (2.1 (0.5) v 3.0 (0.7) mm Hg, p < 0.01), a higher distensibility (1.1 (0.3) v 0.8 (0.3) mm Hg(−1).10(−2), p < 0.01), similar cross sectional compliance (0.14 (0.04) v 0.15 (0.05) mm(2).mm Hg(−1), p > 0.05), and lower incremental elastic modulus (7.4 (2.0) v 14.0 (5.0) mm Hg.10(2); p < 0.001).
CONCLUSIONS—The compliance of the large elastic arteries is not modified in Williams syndrome, even though increased intima-media thickness and lower arterial stiffness are consistent features. Therefore systemic hypertension cannot be attributed to impaired compliance of the arterial tree in this condition.


Keywords: elastin; Williams syndrome; hypertension; complianc

Impaired cardiac adrenergic innervation assessed by MIBG imaging as a predictor of treatment response in childhood dilated cardiomyopathy

OBJECTIVE—To evaluate the prognostic value of metaiodobenzylguanidine (MIBG) imaging in childhood cardiomyopathy.
DESIGN—Prospective cohort study.
SETTING—Tertiary referral centre.
PATIENTS—40 children (21 boys, 19 girls; mean (SD) age, 7.0 (5.6) years) with heart failure resulting from idiopathic dilated cardiomyopathy (n = 23) or various other disorders (n = 17).
METHODS—At the initial examination, cardiac (123)I-MIBG uptake and release, circulating noradrenaline (norepinephrine) concentration, x ray cardiothoracic ratio, and echocardiographic variables were recorded. Cardiac MIBG uptake was obtained by measuring the heart to mediastinum activity ratio on the planar image obtained four hours after MIBG injection. MIBG washout rate was evaluated using relative decrease in cardiac activity measured at 20 minutes and four hours. Patients were treated with angiotensin converting enzyme inhibitors, diuretics, and digitalis, and were followed up for 12 (10) months. Fifteen patients did not respond to medical treatment (12 heart transplants; three deaths), and 25 did respond (improved or stable).
RESULTS—Cardiac MIBG uptake was positively correlated with x ray cardiothoracic index (r = 0.55, p = 0.0008) and echocardiographic left ventricular fractional shortening (r = 0.68, p < 0.0001). Among all the clinical and laboratory variables tested, multivariate discriminant analysis showed that the only independent predictor of an unfavourable outcome was a low MIBG uptake (p < 0.001). Survival curves had a mean threshold value of 1.54 for MIBG uptake.
CONCLUSIONS—Impaired cardiac adrenergic innervation is strongly related to adverse outcome in children with dilated cardiomyopathy, independently of the aetiology. MIBG imaging may help to stratify risk in such patients.


Keywords: noradrenaline; MIBG; single photon imaging; children; cardiomyopath