Duct Stenting Versus Modified Blalock-Taussig Shunt in Neonates With Duct-Dependent Pulmonary Blood Flow: Associations With Clinical Outcomes in a Multicenter National Study.

BACKGROUND: Infants born with cardiac abnormalities causing dependence on the arterial duct for pulmonary blood flow are often palliated with a shunt usually between the subclavian artery and either pulmonary artery. A so-called modified Blalock-Taussig shunt allows progress through early life to an age and weight at which repair or further more stable palliation can be safely achieved. Modified Blalock-Taussig shunts continue to present concern for postprocedural instability and early mortality such that other alternatives continue to be explored. Duct stenting (DS) is emerging as one such alternative with potential for greater early stability and improved survival. METHODS: The purpose of this study was to compare postprocedural outcomes and survival to next-stage palliative or reparative surgery between patients undergoing a modified Blalock-Taussig shunt or a DS in infants with duct-dependent pulmonary blood flow. All patients undergoing cardiac surgery and congenital interventions in the United Kingdom are prospectively recruited to an externally validated national outcome audit. From this audit, participating UK centers identified infants <30 days of age undergoing either a Blalock-Taussig shunt or a DS for cardiac conditions with duct-dependent pulmonary blood flow between January 2012 and December 31, 2015. One hundred seventy-one patients underwent a modified Blalock-Taussig shunt, and in 83 patients, DS was attempted. Primary and secondary outcomes of survival and need for extracorporeal support were analyzed with multivariable logistic regression. Longer-term mortality before repair and reintervention were analyzed with Cox proportional hazards regression. All multivariable analyses accommodated a propensity score to balance patient characteristics between the groups. RESULTS: There was an early (to discharge) survival advantage for infants before next-stage surgery in the DS group (odds ratio, 4.24; 95% confidence interval, 1.37-13.14; P=0.012). There was also a difference in the need for postprocedural extracorporeal support in favor of the DS group (odds ratio, 0.22; 95% confidence interval, 0.05-1.05; P=0.058). Longer-term survival outcomes showed a reduced risk of death before repair in the DS group (hazard ratio, 0.25; 95% confidence interval, 0.07-0.85; P=0.026) but a slightly increased risk of reintervention (hazard ratio, 1.50; 95% confidence interval, 0.85-2.64; P=0.165). CONCLUSIONS: DS is emerging as a preferred alternative to a surgical shunt for neonatal palliation with evidence for greater postprocedural stability and improved patient survival to destination surgical treatment.

Pseudohyperkalaemia with acute leukaemia: association with pneumatic tube transport of blood specimens.

Falsely elevated serum or plasma potassium level can be the result of mechanical injury to blood cells. We describe pseudohyperkalaemia caused by pneumatic tube transport of blood specimens from a patient with leukaemia. Clinicians should be aware of this possibility when interpreting the clinical significance of hyperkalaemia. In leukaemic patients, pneumatic tube transport of blood specimens for potassium analysis should be avoided.

Transcatheter ablation of atrioventricular junctional re-entrant tachycardia in children and adolescents in Hong Kong: comparison of cryothermal with radiofrequency energy.

OBJECTIVE: To compare the outcome of cryothermal and radiofrequency energy transcatheter ablation of atrioventricular junctional re-entrant tachycardia in children and adolescents. DESIGN: Case series with internal comparison. SETTING: Two hospitals in Hong Kong. PATIENTS: Consecutive transcatheter ablation procedures for atrioventricular junctional re-entrant tachycardia in children and adolescents in our unit from August 2000 to September 2008 were retrospectively reviewed. Radiofrequency ablation was performed from August 2000 to June 2005, and cryoablation from July 2005 to September 2008. MAIN OUTCOME MEASURES: Demographic data, outcome and procedural details. RESULTS: Thirty-eight procedures were reviewed. The radiofrequency ablation group (n=20) and cryoablation group (n=18) had similar demographic characteristics, except that there were more patients with congenital heart disease in the latter group (P=0.03). Acute procedural success rate was 100% in both groups. One patient from the radiofrequency ablation group had recurrence of atrioventricular junctional re-entrant tachycardia. The frequency of post-ablation persistent heart block was higher in the radiofrequency ablation than cryoablation group (10% vs 0%, P=0.17), but this difference was not statistically significant. A shorter fluoroscopy time was noted in the cryoablation group (31 ± 13 vs 38 ± 18 minutes; P=0.03). CONCLUSIONS: Transcatheter cryoablation for atrioventricular junctional re-entrant tachycardia in children and adolescents is as effective as radiofrequency ablation over the medium term. It has an excellent safety profile in terms of avoiding heart block.

Achieving biventricular circulation in patients with moderate hypoplastic right ventricle in pulmonary atresia intact ventricular septum after transcatheter pulmonary valve perforation.

OBJECTIVE: Transcatheter valve perforation for pulmonary atresia intact ventricular septum is the standard of care for patients with mild right ventricular hypoplasia. However, its role in moderate right ventricular hypoplasia has been less well defined. We sought to report the long-term outcome of patients with moderate hypoplastic right ventricle who had undergone the procedure. DESIGN, SETTINGS, AND PATIENTS: We performed a retrospective analysis on patients who had undergone transcatheter pulmonary valve perforation from January 1996 to January 2015 at our institution. The procedures would be carried out irrespective of the right ventricular size, as long as there were no absolute contraindications. INTERVENTION AND OUTCOME MEASURES: Demographic and procedural data were correlated with outcome measures. Outcomes analyzed included procedural success, reintervention rates, final circulation type, and functional class. Multivariate analysis and receiver operator curve were used to identify for parameters in predicting biventricular circulation. RESULTS: The procedural success rate was 92% (33 out of 36) in this group with moderate right ventricular hypoplasia (tricuspid valve z score -4.2 ± 3.0, 69.4% of patients with z score <-2.5). Early reintervention rate was 39%, mostly being insertion of modified Blalock-Taussig shunt. Overall reintervention-free survival was 53%, 30%, and 19% at 1, 6, and 12 months postintervention. Despite no significant catch-up right ventricular growth, majority of survivors (84%) enjoyed a biventricular circulation with good functional status. A tricuspid to mitral valve ratio >0.79 was a good predictor of biventricular outcome. (specificity of 100%, positive predictive value 100%) CONCLUSION: Encouraging long-term results with biventricular circulation and functional status were demonstrated with transcatheter pulmonary valve perforation in patients even with moderate hypoplastic right ventricle, which is comparable to that with mild right ventricular hypertrophy. The baseline tricuspid to mitral valve ratio was identified as a potentially useful tool in predicting biventricular circulation.

Arterial mechanics at rest and during exercise in adolescents and young adults after arterial switch operation for complete transposition of the great arteries.

We sought to determine the arterial mechanics at rest and during exercise in adolescents and young adults with complete transposition of the great arteries after arterial switch operation and their relations with neoaortic complications. Thirty patients (22 men) aged 16.2 ± 2.1 years and 22 controls (15 men) were studied. Central and peripheral arterial pulse wave velocities, carotid and radial augmentation indices, and central systolic blood pressure (cSBP) were determined by oscillometry and applanation tonometry, whereas arterial dimensions were measured by 2-dimensional echocardiography. Arterial strain, distensibility, and stiffness were determined at rest and during supine bicycle exercise testing. At rest, patients had significantly higher heart-carotid pulse wave velocity, carotid and radial augmentation indices, and cSBP than controls. At rest and during submaximal exercise, patients had significantly lower aortic strain and distensibility, greater aortic and carotid stiffness, and higher SBP than controls. Dilated aortic sinus found in 23 (76.7%) patients was associated with lower aortic distensibility, greater aortic stiffness, and higher cSBP at rest and lower aortic distensibility and strain at submaximal exercise. Significant aortic regurgitation found in 20% (6 of 30) of patients was associated with significantly higher neoaortic z scores. Multivariate analysis identified aortic stiffness at rest (ß = 0.46, p = 0.003) and age at operation (ß = 0.44, p = 0.004) as significant determinants of aortic sinus z scores. In conclusion, altered mechanics of the central arteries are present at rest and during exercise in adolescents and young adults after arterial switch operation. These findings may have important implications on progression of neoaortic root dilation, exercise recommendations, and medical therapy.

Left ventricular contractile reserve after arterial switch operation for complete transposition of the great arteries: an exercise echocardiographic study.

AIMS: This study tested the hypothesis that left ventricular (LV) contractile reserve is altered in patients after arterial switch operation (ASO) for complete transposition of the great arteries (TGA) by non-invasive determination of LV force-frequency relationship (FFR). METHODS AND RESULTS: Thirty-two patients aged 16.2 ± 2.1 years and 22 healthy controls were studied. M-mode parameters, transmitral early (E) and late (A) diastolic velocities, and tissue Doppler-derived systolic (sm), early (em), and late (am) diastolic mitral annular velocities were determined at baseline and during submaximal exercise testing. The LV myocardial isovolumic acceleration (IVA) was measured at different heart rates during exercise for derivation of LV FFR and the average slope of IVA increment with heart rate. At baseline, patients had significantly greater E velocity, E/A and E/em ratios, shorter E deceleration time, and reduced mitral annular sm, em, and am velocities (all P < 0.05), but similar IVA (P = 0.29) compared with controls. During exercise, sm and em remained significantly reduced (P < 0.001), and LV IVA became lower (P < 0.001) in patients. The average FFR slope was significantly lower in patients (0.039 ± 0.019 vs. 0.070 ± 0.024 m/s(2) bpm, P < 0.001). The weighted average FFR curve of patients was flattened compared with the reported positive FFR reference curve based on a healthy paediatric cohort (P < 0.0001). Patients with variant compared with those with usual coronary arterial anatomy had significant flattening of FFR (P < 0.001) and a reduced FFR slope (P = 0.007). CONCLUSION: In adolescents and young adults after ASO, exercise stress revealed reduced LV contractile reserve, which is worse in those having variant coronary arterial anatomy.