Sylvia Sm Chen

Outcome in adult patients after arterial switch operation for transposition of the great arteries

BACKGROUND The arterial switch operation (ASO) is currently the treatment of choice in neonates with transposition of the great arteries (TGA). The outcome in childhood is encouraging but only limited data for long-term outcome into adulthood exist. METHODS AND RESULTS We studied 145 adult patients (age>16, median 25 years) with ASO followed at our institution. Three patients died in adulthood (mortality 2.4/1000-patient-years). Most patients were asymptomatic and had normal left ventricular function. Coronary lesions requiring interventions were rare (3 patients) and in most patients related to previous surgery. There were no acute coronary syndromes. Aortic root dilatation was frequent (56% patients) but rarely significant (>45 mm in 3 patients, maximal-diameter 49 mm) and appeared not to be progressive. There were no acute aortic events and no patient required elective aortic root surgery. Progressive neo-aortic-valve dysfunction was not observed in our cohort and only 1 patient required neo-aortic-valve replacement. Many patients (42.1%), however, had significant residual lesions or required reintervention in adulthood. Right ventricular outflow tract lesions or dysfunction of the neo-pulmonary-valve were frequent and 8 patients (6%) required neo-pulmonary-valve replacement. Cardiac interventions during childhood (OR 3.0, 95% CI 1.7-5.4, P<0.0001) were strong predictors of outcome (cardiac intervention/significant residual lesion/death) in adulthood. CONCLUSIONS Adult patients with previous ASO remain free of acute coronary or aortic complications and have low mortality. However, a large proportion of patients require re-interventions or present with significant right sided lesions. Life-long cardiac follow-up is, therefore, warranted. Periodic noninvasive surveillance for coronary complications appears to be safe in adult ASO patients.

The shape and function of the right ventricle in Ebstein's anomaly

BACKGROUND Ebsteins anomaly involves both the right ventricle (RV) and tricuspid valve. METHODS The functional RV and tricuspid orifice were traced from magnetic resonance images in 29 adult Ebstein patients and 9 normal subjects and reconstructed for visualization and measurement of regional RV size, function, and shape at 20 cross sections, and inlet and outflow tract ejection fractions (EFs). RESULTS The RV in Ebsteins had RV dilation (end diastolic volume index 179 ± 69 vs. 84 ± 22 ml/m(2) in normals, p<0.001) and global dysfunction (EF 45 ± 8 vs. 55 ± 5% in normals, p<0.001). Longitudinal contraction was preserved (26 ± 13 vs. 26 ± 4 mm in normals) and correlated more weakly with EF than short axis fractional shortening (r=0.44 vs. r=0.71, p<0.05 for both). The apical region in Ebsteins RV was enlarged, rounded and contributed more than normal to the global stroke volume. However this contribution correlated inversely with global EF. In contrast slices in the basal region had normal cross sectional area and their function correlated directly with global EF. Inlet EF was depressed (46 ± 8% vs. 55 ± 6 in normals, p=.002); outflow tract EF was even more depressed (39 ± 14, p=0.019). CONCLUSION The three dimensional shape of the RV in adult Ebstein patients was demonstrated. The Ebsteins RV remodels in diverse regional patterns rather than following a shape continuum. Changes at the apex and base had opposing effects on function. Global EF was supported more by short axis than longitudinal contraction.

Prevalence and prognostic implication of restenosis or dilatation at the aortic coarctation repair site assessed by cardiovascular MRI in adult patients late after coarctation repair

BACKGROUND Cardiovascular magnetic resonance (CMR) is ideal for assessing patients with repaired aortic coarctation (CoA). Little is known on the relation between long-term complications of CoA repair as assessed by CMR and clinical outcome. We examined the prevalence of restenosis and dilatation at the repair site and the long-term outcome in patients with repaired CoA. METHODS AND RESULTS CMR imaging and clinical data for adult CoA patients (247 patients aged 33.0 ± 12.8 years, 60% male), were analyzed. The diameter of the aorta at the repair site was measured on CMR and its ratio to the aortic diameter at the diaphragm (repair site-diaphragm ratio, RDR) was calculated. Restenosis (RDR≤70%) was present in 31% of patients (and significant in 9% [RDR<50%]), and dilatation (RDR>150%) in 13.0%. A discrete aneurysm at the repair site was observed in 9%. Restenosis was more likely after resection and end-end anastomosis, whereas dilatation after patch repair. Systemic hypertension was present in 69% of patients. Of the hypertensive patients, blood pressure (133 ± 20/73 ± 10 mm Hg) was well controlled in 93% with antihypertensive therapy. Mortality rate over a median length of 5.9 years was low (0.69% per year, 95% CI: 0.33-1.26), but significantly higher than age-matched healthy controls (standardised mortality ratio 2.86, CI 1.43-5.72, p<0.001). CONCLUSION Restenosis or dilatation at the CoA repair site as assessed by CMR is not uncommon. Medium term survival remains good, however, albeit lower than in the general population. Life-long follow-up and optimal blood pressure control are likely to secure a good longer term outlook in these patients.

Cardiovascular magnetic resonance tagging of the right ventricular free wall for the assessment of long axis myocardial function in congenital heart disease

BackgroundRight ventricular ejection fraction (RV-EF) has traditionally been used to measure and compare RV function serially over time, but may be a relatively insensitive marker of change in RV myocardial contractile function. We developed a cardiovascular magnetic resonance (CMR) tagging-based technique with a view to rapid and reproducible measurement of RV long axis function and applied it in patients with congenital heart disease.MethodsWe studied 84 patients: 56 with repaired Tetralogy of Fallot (rTOF); 28 with atrial septal defect (ASD): 13 with and 15 without pulmonary hypertension (RV pressure > 40 mmHG by echocardiography). For comparison, 20 healthy controls were studied. CMR acquisitions included an anatomically defined four chamber cine followed by a cine gradient echo-planar sequence in the same plane with a labelling pre-pulse giving a tag line across the basal myocardium. RV tag displacement was measured with automated registration and tracking of the tag line together with standard measurement of RV-EF.ResultsMean RV displacement was higher in the control (26 ± 3 mm) than in rTOF (16 ± 4 mm) and ASD with pulmonary hypertension (18 ± 3 mm) groups, but lower than in the ASD group without (30 ± 4 mm), P < 0.001. The technique was reproducible with inter-study bias ± 95% limits of agreement of 0.7 ± 2.7 mm. While RV-EF was lower in rTOF than in controls (49 ± 9% versus 57 ± 6%, P < 0.001), it did not differ between either ASD group and controls.ConclusionsMeasurements of RV long axis displacement by CMR tagging showed more differences between the groups studied than did RV-EF, and was reproducible, quick and easy to apply. Further work is needed to assess its potential use for the detection of longitudinal changes in RV myocardial function.

Physiologic determinants of exercise capacity in patients with different types of right-sided regurgitant lesions: Ebstein's malformation with tricuspid regurgitation and repaired tetralogy of Fallot with pulmonary regurgitation

BACKGROUND Exercise capacity relates to right ventricular (RV) volume overload in congenital heart disease and may improve after surgery. We herewith investigate the relation between exercise capacity, cardiac index, and RV volume overload due to tricuspid regurgitation (TR) in Ebsteins malformation and pulmonary regurgitation (PR) after repair of tetralogy of Fallot (rToF). METHODS We measured cardiac index and tricuspid/pulmonary regurgitant fraction by cardiovascular magnetic resonance in patients with Ebsteins malformation (n = 40) or rTOF (n = 53) with at least moderate TR/PR and 24 healthy controls. Exercise tolerance was determined by peak oxygen consumption (peak VO2) during cardiopulmonary exercise testing. RESULTS TR and PR fraction were similar in Ebstein and rTOF patients (43 ± 17% versus 39 ± 12%, respectively). Cardiac index was reduced in Ebstein (2.7 ± 0.6L/min/m(2) compared to controls 3.5 ± 0.9L/min/m(2), p < 0.001) but not in rToF patients (3.2 ± 0.5L/min/m(2)). Multiple regression analysis revealed a significant correlation between peak VO2 and cardiac index in Ebstein. Furthermore, peak VO2 correlated with peak heart rate in both groups but not with regurgitation fraction. CONCLUSIONS Despite comparable amounts of regurgitation from a right sided heart valve in patients with Ebstein and rToF, reduction of cardiac index was observed only in the former group. Greater physiologic complexity and adverse ventricular interaction with chronotropic incompetence in Ebsteins malformation may account for this.

Sudden cardiac death in Ebstein's malformation due to a cardiac haemangioma

A previously well 22-year-old man suddenly collapsed during a football game. Prolonged resuscitation of 50 min was unsuccessful. Pathological examination demonstrated Ebsteins malformation with apical displacement by 30 mm of the septal and posterior tricuspid valve leaflets ( Panel A ), and rotation of the septal leaflet into the right ventricular outflow tract (RVOT). The anterior …

Unilateral pulmonary artery branch stenosis: Diastolic prolongation of forward flow appears to maintain flow to the affected lung if the pulmonary valve is competent

BACKGROUND We sought to improve understanding of the diastolic prolongation of forward flow seen through a unilateral branch pulmonary artery (PA) stenosis. METHODS AND RESULTS Of patients studied by cardiovascular magnetic resonance (CMR) for congenital heart disease, we reviewed right and left PA flow to find 10 cases with a diastolic prolongation of flow in a stenosed branch PA. They were aged 20 years (median, range = 14-40 years, 7 males). Seven had transposition of the great arteries corrected by arterial switch (TGA-AS) and 3 had repaired tetralogy of Fallot (rToF). All had at least moderate unilateral stenosis and competent pulmonary valves. For comparison, we identified 10 patients with unilateral stenosis and at least moderate pulmonary regurgitation, 9 rTOF and 1 TGA-AS, aged 23.5 years (range = 14-42 years, 6 males). Flow in each PA was measured, and in 10 healthy volunteers aged 27 years (range = 20-42 years, 5 males). The curves of flow through stenosed and non-stenosed arteries were averaged for each patient group and compared with those from controls. In competent pulmonary valve patients, the minimum diameters of the stenosed versus non-stenosed branches were as follows (median [range]): 4 [3-8] mm versus 13.5 [10-28] mm, p<0.001, although their flows differed a little: 2.5 [1.5-6.8] L/min versus 3.2 [1.2-8.8] L/min, p=0.6. No diastolic tail was identifiable in the patients with unilateral PA stenosis and pulmonary regurgitation, where stenosed versus non-stenosed diameters were 7 [4-12] mm versus 20.5 [13-33] mm, p<0.001, and flows differed: 1.3 [0.4-2.9] L/min versus 3.8 [3.0-5.0] L/min, p<0.001. No controls showed stenosis or diastolic tail. CONCLUSIONS Beyond a competent pulmonary valve, flow through a unilateral PA stenosis, although limited in systole, can continue into diastole, maintaining flow to the lung.

Late Stenosis After Repair of Anomalous Pulmonary Venous Drainage and the Value of Cardiovascular Magnetic Resonance for Assessment of This Important Complication

A 25-year-old woman presented with hemoptysis and breathlessness. She had undergone previous surgical repair in 1983 for total anomalous pulmonary venous connection (APVC), with ligation of the vertical vein, anastomosis of the pulmonary venous confluence to the left atrium, and closure of a secundum atrial septal defect. Pulmonary embolism was excluded on multislice computed tomography. Echocardiography showed continous pulmonary venous flow on color Doppler (Fig. 1a, b), suggesting stenosis at the previous repair site, although a definite location could not be identified. Subsequent cardiovascular magnetic resonance (CMR) study showed drainage of all four pulmonary veins into a pulmonary venous confluence at the superior aspect of the left atrium and confirmed significant stenosis at the anastomosis of this chamber with the left atrium (Fig. 1c, d, Movie 1). The peripheral pulmonary veins were dilated but without stenosis (Fig. 1e). Flow analysis at the site of anastomosis (Fig. 2a) showed continous flow consistent with significant stenosis, a peak recorded velocity of 2.3 m/s (normal, \1 m/s), and an orifice diameter of 6 9 9 mm. No pulmonary hypertension or residual atrial septal defect was identified. Biventricular size and function were normal. The patient underwent successful transseptal puncture and balloon dilation of the stenosis (Fig. 2a, b). Follow-up CMR showed patent pulmonary venous confluence to left atrial connection and phasic flow (Fig. 2c, d, Movie 2).

Diastolic prolongation of forward flow in branch pulmonary artery stenosis

Summary Diastolic prolongation of forward flow, or diastolic tail is present in unilateral branch pulmonary artery stenosis in patients after the arterial switch operation for transposition of the great arteries and after repair for tetralogy of Fallot. Interestingly, as a result of a diastolic tail, flow through the stenosed artery is comparable to that in the non-stenosed artery and therefore the impact of stenosis may be relieved. Background Diastolic prolongation of forward flow, or diastolic tail, is known as an indicator of the hemodynamic impact of aortic coarctation or recoarctation. We have observed similarly tailed flow curves in unilaterally stenosed branch pulmonary arteries (PA) of patients with transposition of the great arteries corrected by arterial switch (TGA-AS) and after repair of tetralogy of Fallot (rToF). We are not aware that this has been described before. We aimed to improve understanding of the nature and possible clinical implications of this pathophysiological finding. Methods Our clinical cardiovascular magnetic resonance (CMR) reports on TGA-AS and rTOF patients of the last five years (200 and 350, respectively) were searched for the above finding. It had been noticed from the appearances of cine images and through-plane velocity acquisitions aligned with or transecting, respectively, the right and left PAs. Diastolic tail was confirmed by clear discrepancy between the curves of stenosed and non-stenosed PA flow (Figure 1A). CMRtools was used to measure the volume of flow through each branch PA. The branch PA flow curves of 10 healthy volunteers aged 28 ±5 years, 6 male, were studied for comparison. Results

The relation between significant stenosis or dilatation at the repair site and outcome in a contemporary cohort of patients with repaired aortic coarctation as assessed using Cardiovascular Magnetic Resonance.

Summary Complications of restenosis or dilatation at the site of repair may occur late after initial repair of coarctation of the aorta (CoA). Cardiovascular magnetic resonance (CMR) is becoming the choice of imaging of patients after CoA. Using CMR, we studied the relation between these complications and outcome inn patients with previous CoA repair, and found that significant stenosis or dilatation at the repair site is a predictor of adverse outcome. Background Cardiovascular magnetic resonance (CMR) is becoming the method of choice for assessing repaired CoA patients, especially for identifying important long-term sequelae of restenosis or dilatation at the repair site. We examined the prevalence of restenosis and dilatation at the site of aortic coarctation (CoA) repair and their relation to long-term outcome in patients with repaired CoA.