Atrial Redirection Surgery Research Articles

32 year follow up of patients following atrial redirection surgery for transposition of the great arteries.

A significant body of patients who have undergone Mustard or Senning procedure require lifelong follow up. In this retrospective review, we examined the cohort of such patients currently attending our center. Patients who had undergone either Mustard or Senning procedure were identified. We retrospectively reviewed medical records, recorded demographic information and data regarding the clinical state, NHYA class, cardiopulmonary exercise testing, NT-proBNP measurement, and recent cardiac MRI findings. Forty-six patients were identified, the mean age was 32.2years (± 6.1years), 67.4% were male. Thirty-two patients (69.6%) had undergone a Senning procedure. The median length of the follow-up was 32years. Thirty-two patients (69.6%) were NHYA class 1. The mean VO2max achieved was 24.2±5.8mL/min/kg. The mean NT-proBNP was 266.4pg/mL (± 259.9pg/mL). The mean right ventricular end-diastolic volume (RVEDV) was 212.4mL±73.1mL (indexed 114.2mL/m2 ±34.4mL/m2 ). The mean right ventricular ejection fraction (RVEF) was 53.7% ± 7.9%. The mean left ventricular end-diastolic volume (LVEDV) was 161.5mL±73.7mL (indexed 87.8mL/m2 ±41.1mL/m2 ). The mean left ventricular ejection fraction (LVEF) was 59.8% ± 5.7%. There was a significant correlation between right ventricular (RV) size on MRI and NT-proBNP level. We present a relatively well cohort of patients with overall favorable long-term outcome. The majority of patients are NHYA class 1 and the systemic right ventricular function appears to be well preserved as assessed by MRI. The exercise tolerance is reduced, with the majority of patients achieving around 60% of the estimated VO2max . Regular specialist follow-up and assessment with advanced imaging at regular intervals remain important for this group.

Role of myocardial collagen degradation and fibrosis in right ventricle dysfunction in transposition of the great arteries after atrial switch

BackgroundHeart failure is a serious event in patients with transposition of the great arteries (D-TGA) after atrial redirection surgery. We aimed to determine the association between myocardial fibrosis and systolic and diastolic systemic right ventricle (sRV) dysfunction. MethodsDiastolic and systolic function of sRV was prospectively assessed using echocardiography and cardiac magnetic resonance imaging (CMR) in 48 patients with atrially switched D-TGA and 26 healthy subjects. Diastolic function of the subaortic ventricle was assessed by echocardiography Doppler and DTI. In CMR, ejection fraction of sRV and wall stress defined as the product of the systolic blood pressure and volume/mass ratio were assessed. Fibrosis extent within sRV myocardium was evaluated using gadolinium-enhanced magnetic resonance and serum collagen turnover biomarkers. ResultsLate gadolinium enhancement (LGE) was found in 35% of D-TGA patients, and the collagen degradation biomarker pro-MMP1:TIMP1 ratio was significantly increased in D-TGA patients compared to healthy subjects (1.0 × 10−2vs. 2.5 × 10−2, p = 0.04). Increase in sRV wall stress was significantly associated with LGE (p = 0.01) and pro-MMP1:TIMP1 ratio (r = 0.77, p < 0.01). After adjustment for age, sex, BMI, blood pressure and cardiac treatment, pro-MMP1:TIMP1 ratio was the strongest determinant of sRVEF (R2 = 0.85, p < 0.01). Pro-MMP1:TIMP1 ratio was also significantly correlated with the early diastolic filling parameter E/E′ (r = 0.53, p = 0.02), but this was not anymore the case after adjustment. ConclusionsDiastolic and systolic sRV dysfunction is related to myocardial collagen degradation and fibrosis. Research in medical therapies that reduce systemic sRV afterload and limit collagen degradation is warranted in this setting.

Stress Echocardiographic Evaluation for D-Transposition of the Great Arteries after Atrial Redirection: Unmasking Early Signs of Myocardial Dysfunction and Baffle Stenosis

The authors used semisupine cycle ergometry stress echocardiography to assess cardiac function and unmask baffle stenosis in patients with d-transposition of the great arteries after atrial redirection surgery. This was a retrospective review of semisupine cycle ergometry stress echocardiography performed in 53 patients (64% male; mean age, 24.0years; 90% Mustard procedure) and 56 healthy control subjects. Incremental exercise to volitional fatigue was performed. Hemodynamic data, echocardiographic cardiac dimensions, area change, tissue Doppler velocities, strain, ventricular synchronization, and superior vena cava flow velocities before and immediately after exercise are reported. Patients had lower exercise capacity (870 vs 1,854 J/kg, P<.001) and peak heart rates (132 vs 167 beats/min, P<.001). Stroke volume index did not increase with exercise (45 vs 47mL/m2, P=.400). Cardiac index increased in both groups with exercise (3.0 vs 6.1 and 2.9 vs 7.0L/min/m2, P<.001) and was higher in control subjects (P=.006). Right ventricular diastolic and systolic areas decreased significantly with exercise in both the short-axis and four-chamber views. Right and left ventricular contraction time shortened with exercise (405 vs 247 and 338 vs 217msec, P<.001) and remained synchronous (ratio of right ventricular to left ventricular contraction time=0.080). Doppler velocities in patients with baffle obstruction were higher in the lower superior vena cava with exercise compared with nonobstructed patients (1.87 vs 1.46m/sec, P=.020) and normalized after catheter intervention (1.49 vs 1.46m/sec, P=.800). Patients with d-transposition of the great arteries have lower exercise capacity and peak heart rates. The systemic right ventricle presents a lesser but qualitatively normal systolic response and decreased diastolic filling. Semisupine cycle ergometry stress echocardiography unmasked SVC obstruction.

Cardiac magnetic resonance imaging characteristics and pregnancy outcomes in women with Mustard palliation for complete transposition of the great arteries

BackgroundWomen with transposition of the great arteries (TGA) following atrial redirection surgery are at risk of pregnancy-associated arrhythmia and heart failure. The cardiovascular magnetic resonance imaging (CMR) characteristics of these women and the relationship of CMR findings to pregnancy outcomes have not been described. MethodsWe included 17 women with atrial redirection surgery and CMR within 2years of delivery. ResultsAll women were asymptomatic at baseline (New York Heart Association Class 1). CMR studies were completed pre-pregnancy in 3, antepartum/peripartum in 2, and postpartum in 12 women. Three women (3/17, 18%) experienced major cardiovascular events related to pregnancy: cardiac arrest (n=1) and symptomatic atrial arrhythmia (n=2). Median gestational age at delivery was 38weeks (24–39weeks) and birth weight was 2770g (2195–3720g). Complications were seen in 3 offspring (3/17, 18%): death (n=1) and prematurity (n=2). CMR characteristics included median right ventricular end diastolic volume 119mL/m2 (range 85–214mL/m2) and median right ventricular ejection fraction (RVEF) 37% (range 30–51%). All women with cardiovascular complications had an RVEF <35% (range 32–34%). The association between RVEF <35% and cardiovascular complications trended towards statistical significance (p=0.05). No statistically significant differences in CMR measurements were found between those with and without neonatal complications. ConclusionsWhile the majority of women in this cohort had successful outcomes following pregnancy, important cardiovascular complications were seen in a significant minority, all of whom had an RVEF <35%. The preliminary findings of our study provide impetus for a larger prospective study to evaluate the prognostic role of CMR in pregnant women with atrial redirection surgery.

Prognostic Value of NT-proBNP after Atrial Redirection Surgery

After atrial redirection surgery NT-proBNP correlates with NYHA-class, ventricular function and subaortic AV-valve regurgitation (TR). The impact on adverse clinical outcome is unknown.

Systemic right ventricular fibrosis detected by cardiovascular magnetic resonance is associated with clinical outcome, mainly new-onset atrial arrhythmia, in patients after atrial redirection surgery for transposition of the great arteries.

We hypothesized that fibrosis detected by late gadolinium enhancement (LGE) cardiovascular magnetic resonance predicts outcomes in patients with transposition of the great arteries post atrial redirection surgery. These patients have a systemic right ventricle (RV) and are at risk of arrhythmia, premature RV failure, and sudden death. Fifty-five patients (aged 27±7 years) underwent LGE cardiovascular magnetic resonance and were followed for a median 7.8 (interquartile range, 3.8-9.6) years in a prospective single-center cohort study. RV LGE was present in 31 (56%) patients. The prespecified composite clinical end point comprised new-onset sustained tachyarrhythmia (atrial/ventricular) or decompensated heart failure admission/transplantation/death. Univariate predictors of the composite end point (n=22 patients; 19 atrial/2 ventricular tachyarrhythmia, 1 death) included RV LGE presence and extent, RV volumes/mass/ejection fraction, right atrial area, peak Vo(2), and age at repair. In bivariate analysis, RV LGE presence was independently associated with the composite end point (hazard ratio, 4.95 [95% confidence interval, 1.60-15.28]; P=0.005), and only percent predicted peak Vo(2) remained significantly associated with cardiac events after controlling for RV LGE (hazard ratio, 0.80 [95% confidence interval, 0.68-0.95]; P=0.009/5%). In 8 of 9 patients with >1 event, atrial tachyarrhythmia, itself a known risk factor for mortality, occurred first. There was agreement between location and extent of RV LGE at in vivo cardiovascular magnetic resonance and histologically documented focal RV fibrosis in an explanted heart. There was RV LGE progression in a different case restudied for clinical indications. Systemic RV LGE is strongly associated with adverse clinical outcome especially arrhythmia in transposition of the great arteries, thus LGE cardiovascular magnetic resonance should be incorporated in risk stratification of these patients.

Myocardial T1 mapping in pediatric and congenital heart disease.

In addition to the depiction of anatomy and function, tissue characterization of the myocardium has emerged as an important asset of cardiac magnetic resonance (CMR). Among the tissue properties that are quantifiable by CMR is diffuse myocardial fibrosis. Diffuse fibrosis is regarded to be the common pathological pathway toward loss of myocardial function in many cardiac conditions, including congenital heart disease.1–4 As fibrosis seems to have a major role in myocardial failure and may be reversible,5–8 its assessment by CMR has the potential to transform the way we monitor and treat our patients.9 In this review, we describe the technical aspects of fibrosis quantification with CMR and outline past and potential applications in congenital and pediatric heart disease. Diffuse myocardial fibrosis, which is present to a varying degree in children with acquired and congenital heart disease, has been attributed to abnormal loading conditions, cyanosis, and genetic predisposition.1,7,10,11 Myocardial fibrosis manifests in the pressure-loaded left ventricle of infants and children with aortic stenosis and coarctation.1 In patients with tetralogy of Fallot right ventricular myofiber disorganization and interstitial fibrosis have been demonstrated histologically.2,12 Interestingly, right ventricular fibrosis not only occurs in late adult survivors, but is already present in infants with this condition.12 The changes in myocardial architecture observed with fibrotic remodeling can be detrimental to heart function: Fibrous endocardial thickening of the right ventricular infundibulum is a predictor of poor right ventricular function in patients after tetralogy of Fallot repair.3 In patients with tricuspid atresia myocardial fibrosis is associated with systolic ventricular dysfunction early in life.4,13 In addition to being a mediator of cardiac dysfunction, diffuse fibrosis is the substrate for electric instability and a risk factor for life-threatening ventricular arrhythmia.14 Antifibrotic drugs have …

Systemic right ventricular fibrosis detected by CMR predicts adverse clinical outcome in patients after atrial redirection surgery for transposition of the great arteries

Background The cross-sectional nature of our previous study by late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) in systemic right ventricle (RV) patients limited our ability to make conclusions about the prognostic predictive value of LGE in this population. Therefore, we performed this larger prospective study to determine whether fibrosis detected by LGE CMR would predict adverse outcomes in patients treated for transposition of the great arteries by atrial redirection surgery with RV in the systemic position and at risk of arrhythmia, premature RV failure, and sudden death. Methods Fifty-five patients (aged 27±7 years) underwent LGE CMR and were followed for a mean of 6.5±3.2 years in a single-centre study. The pre-specified composite clinical endpoint consisted of new-onset sustained atrial/ventricular tachyarrhythmia or decompensated heart failure admission/transplantation/death. Results RV LGE was present in 31 (56%) patients. In 8 out of 9 (89%) patients with more than one event, atrial tachyarrhythmia, itself a known risk factor for mortality, occurred first. Univariate predictors of the composite endpoint (n=22 patients; 19 atrial/2 ventricular tachyarrhythmia, 1 death) included RV LGE presence and extent, RV volumes/mass/ejection fraction, right atrial area, peak VO2 and age at repair. In bivariate analysis, RV LGE presence was independently associated with the composite endpoint, and remained significant (hazard ratio (HR) 4.95[95% confidence interval (CI) 1.60-15.28], p=0.005) when compared with the second independent predictor, percent predicted peak VO2 (HR 0.80[95% CI 0.68-0.95],p=0.009 per 5%). When fibrosis status was added to peak VO2%, risk prediction for cardiac events was further refined. There was clear agreement between location and extent of RV LGE at in vivo CMR and histologically documented focal RV fibrosis in an explanted heart from one of the study patients. Lastly, RV LGE appeared progressively extended in another patient from our cohort restudied for clinical indication. Conclusions

Aerobic training in adults after atrial switch procedure for transposition of the great arteries improves exercise capacity without impairing systemic right ventricular function

BackgroundExercise training safely and efficiently improves symptoms in patients with heart failure due to left ventricular dysfunction. However, studies in congenital heart disease with systemic right ventricle are scarce and results are controversial. In a randomised controlled study we investigated the effect of aerobic exercise training on exercise capacity and systemic right ventricular function in adults with d-transposition of the great arteries after atrial redirection surgery (28.2±3.0years after Mustard procedure). Methods48 patients (31 male, age 29.3±3.4years) were randomly allocated to 24weeks of structured exercise training or usual care. Primary endpoint was the change in maximum oxygen uptake (peak VO2). Secondary endpoints were systemic right ventricular diameters determined by cardiac magnetic resonance imaging (CMR). Data were analysed per intention to treat analysis. ResultsAt baseline peak VO2 was 25.5±4.7ml/kg/min in control and 24.0±5ml/kg/min in the training group (p=0.3). Training significantly improved exercise capacity (treatment effect for peak VO2 3.8ml/kg/min, 95% CI: 1.8 to 5.7; p=0.001), work load (p=0.002), maximum exercise time (p=0.002), and NYHA class (p=0.046). Systemic ventricular function and volumes determined by CMR remained unchanged. None of the patients developed signs of cardiac decompensation or arrhythmias while on exercise training. ConclusionsAerobic exercise training did not detrimentally affect systemic right ventricular function, but significantly improved exercise capacity and heart failure symptoms. Aerobic exercise training can be recommended for patients following atrial redirection surgery to improve exercise capacity and to lessen or prevent heart failure symptoms. (Clinical Trial Registration: ClinicalTrials.gov #NCT00837603)

Prognostic value of NT-proBNP in patients with systemic morphological right ventricles: A single-centre experience

In systemic morphological right ventricles after atrial redirection surgery, NT-proBNP is correlated with NYHA-class, ventricular function and subaortic AV-valve regurgitation (TR). The impact of NT-proBNP on adverse clinical outcomes is, however, unknown. MethodsThis prospectively designed, longitudinal, observational study evaluated NT-proBNP in 116 patients (24.9±4.2years old, NYHA class I/II/III=97/18/1, 71 men) relative to all cardiac causes of hospitalisation, heart failure, transplantation and death. ResultsThe mean observation time was 7.3±2.4years. In univariate Cox proportion analysis, the predictors for all causes of hospitalisation (n=41; 35.5%) were NT-proBNP (HR: 5.99; 95%CI: 3.21–11.18), NYHA class (HR: 2.98; 95%CI: 1.62–5.5), ventricular function (HR: 1.96; 95%CI: 1.27–3.02), TR (HR: 2.39; 95%CI: 1.48–3.59), ventricular septal defect repair (HR: 1.29; 95%CI: 1.08–1.53) and a history of supraventricular tachycardia (SVT) (HR: 7.13; 95%CI: 3.74–13.59). In multivariate Cox proportion analysis, NT-proBNP (HR: 3.71; 95%CI: 1.82–7.57), SVT (HR: 4.27; 95%CI: 2.03–8.94) and ventricular septal defect repair (HR: 1.41; 95%CI: 1.15–1.72) remained independently associated with all causes of hospitalisation.For heart failure, transplantation and death, the single predictors were NT-proBNP (HR: 20.67; 95%CI: 4.69–91.78), NYHA class (HR: 6.45; 95%CI: 2.75–15.14), ventricular function (HR: 2.70; 95%CI: 1.48–4.92), TR (HR: 4.11; 95%CI: 1.99–8.47), QRS duration (HR: 2.09; 95%CI: 1.06–4.12) and SVT (HR: 8.00; 95%CI: 2.82–22.69). Multivariate Cox proportion analysis identified NT-proBNP (HR: 6.82; 95%CI: 1.32–35.04) and NYHA class (HR: 6.79; 95%CI: 1.75–26.28). Using ROC curves, the ability of NT-proBNP to detect patients at risk was greater for heart failure, transplantation and death (AUC: 0.944; 95%CI: 0.900–0.988) than for all causes of hospitalisation (AUC: 0.8; 95%CI: 0.713–0.887). ConclusionIn systemic right ventricles, NT-proBNP is a useful risk predictor for all causes of hospitalisation and, in particular, for heart failure, transplantation and death. It therefore might be a useful tool for risk assessment in this patient population.

Diffuse myocardial fibrosis in the systemic right ventricle of patients late after Mustard or Senning surgery: an equilibrium contrast cardiovascular magnetic resonance study

After atrial redirection surgery (Mustard-Senning operations) for transposition of the great arteries (TGA), the systemic right ventricle (RV) suffers from late systolic failure with high morbidity and mortality. Mechanisms of late RV failure are poorly characterized. We hypothesized that diffuse interstitial expansion representing diffuse fibrosis is greater in systemic RVs of patients following Mustard-Senning surgery and that it would be associated with other markers of heart failure and disease severity. We used equilibrium contrast cardiovascular magnetic resonance (CMR) imaging to quantify extracellular volume (ECV) in the septum and RV free wall of 14 adults presenting to a specialist clinic late after surgery for TGA (8 Mustard, 6 female, median age 33). These were compared with 14 age-and sex-matched healthy volunteers. Patients were assessed with a standardized CMR protocol, NT-brain natriuretic peptide (NT-proBNP), and cardiopulmonary exercise (CPEX) testing. The mean septal ECV was significantly higher in patients than controls (0.254 ± 0.036 vs. 0.230 ± 0.032; P = 0.03). NT-proBNP positively related to septal ECV (P = 0.04; r = 0.55). The chronotropic index (CI) during CPEX testing negatively related to the ECV (P = 0.04; r = -0.58). No relationship was seen with other CMR or CPEX parameters. R.V free wall ECV was difficult to measure (heavy trabeculation, sternal wires, blood pool in regions of interest) with high and poor inter-observer reproducibility: this analysis was abandoned. Septal interstitial expansion is seen in adults late after atrial redirection surgery for TGA. It correlates well with NT-proBNP and CI and may have a role in the development of RV systolic impairment. Measuring interstitial expansion in the RV free wall is difficult using this methodology.

Squeezing better function out of the systemic right ventricle by optimizing its pacing site

The morphologic right ventricle (RV) is the systemic pumping chamber predominantly in 2 types of biventricular congenital heart disease: congenitally corrected transposition of the great arteries and following repair of transposition of the great arteries (TGA) using a Senning or Mustard atrial switch procedure. In both conditions, the systemic RV is prone to fail. Indeed, after the atrial switch procedure for TGA, long-term systemic RV function is a major concern and profoundly affects patient outcomes. Roos-Hesselink et al 1 Roos-Hesselink J.W. Meijboom F.J. Spitaels S.E. et al. Decline in ventricular function and clinical condition after Mustard repair for transposition of the great arteries (a prospective study of 22–29 years). Eur Heart J. 2004; 25: 1264-1270 Crossref PubMed Scopus (198) Google Scholar found that while all patients had good RV function 14 years after undergoing an atrial switch procedure, almost two-thirds showed moderate-to-severe systemic RV dysfunction after 25 years. RV dysfunction was associated with QRS prolongation, a decline in exercise capacity and clinical status and presumably increased need for heart transplant. Reduced myocardial strain and other indices of RV performance form the basis for systemic RV failure in this setting. 2 Eyskens B. Weidemann F. Kowalski M. et al. Regional right and left ventricular function after the Senning operation: an ultrasonic study of strain rate and strain. Cardiol Young. 2004; 14: 255-264 Crossref PubMed Scopus (56) Google Scholar Conversely, RV dysfunction is not commonly seen in the subpulmonary RV when TGA is treated with an arterial switch operation. Therefore, it is the systemic position of the RV that predisposes it to failure. Acute hemodynamic benefits of biventricular and single-site systemic ventricular pacing in patients with a systemic right ventricleHeart RhythmVol. 10Issue 5PreviewPatients treated by atrial redirection surgery (Senning or Mustard procedure) for transposition of the great arteries (TGA) have an important risk for heart failure caused by dysfunction of the systemic right ventricle. Conventional nonsystemic ventricular pacing (non-systVP) may even further increase this risk. Full-Text PDF

Acute hemodynamic benefits of biventricular and single-site systemic ventricular pacing in patients with a systemic right ventricle

Patients treated by atrial redirection surgery (Senning or Mustard procedure) for transposition of the great arteries (TGA) have an important risk for heart failure caused by dysfunction of the systemic right ventricle. Conventional nonsystemic ventricular pacing (non-systVP) may even further increase this risk. We investigated the effects of endocardial non-systVP, biventricular pacing (BiVP), and single-site systemic ventricular pacing (systVP) on systolic cardiac pump function in patients with TGA and status post atrial redirection surgery (SenningMustardTGA). During clinically indicated catheterization in 9 patients with SenningMustardTGA, endocardial ventricular stimulation (overdrive DDD mode; 80-90 beats/min) was applied with temporary pacing leads at the nonsystemic and the systemic ventricle. Acute changes in the maximal rate of pressure rise (dP/dtmax) and systolic pressure of the systemic ventricle, as induced by non-systVP, systVP, and BiVP compared to reference, were assessed with a pressure wire within the systemic ventricle. Reference was AAI pacing with a similar heart rate (n = 7) or non-systVP at a lower heart rate than that during stimulation at experimental sites (85 beats/min vs 90 beats/min; n = 2). Systemic dP/dtmax and systolic ventricular pressure were significantly higher during systVP (+15.6% and +5.1%, respectively) and BiVP (+14.3% and +4.9%, respectively, compared with non-systVP). In 6 of 7 patients, systemic dP/dtmax was higher during BiVP and systVP than during AAI pacing. In a population of patients with SenningMustardTGA, acute hemodynamic effects of endocardial systVP and BiVP were significantly and equally better than those of non-systVP. In some patients, systVP and BiVP might even be better than ventricular activation by the intrinsic conduction system.

Assessment of right ventricular volumes and function using cardiovascular magnetic resonance cine imaging after atrial redirection surgery for complete transposition of the great arteries

Cardiovascular magnetic resonance (CMR) imaging is the reference standard for measurement of right ventricular (RV) volumes and function. To date, no study has compared methods of data acquisition and analysis by CMR for adults with a systemic RV. Our objective was to evaluate RV size and function using axial and short axis views in adults post atrial switch (Mustard) surgery. A total of 34 adults (20 male, mean age at CMR 32 ± 6 years) were identified at our centre. Volumes, RV end-diastolic (EDV) and end-systolic (ESV) were measured in short axis and axial orientations by two independent experienced readers, blinded to clinical and CMR data. Intra and interobserver measurements in each view were compared using Bland-Altman plots and intraclass correlation coefficients (ICC). Although mean volumes were larger in the axial as compared with the short axis view [RVEDV 247 ± 67 vs. 233 ± 54 ml (p = 0.002) and RVESV 148 ± 54 vs. 136 ± 50 ml (p = 0.001)], mean RV ejection fractions (EF) were similar [41 ± 9 % vs. 43 ± 12 % (p = 0.13)]. Bland-Altman plots demonstrated better agreement for axial measures of RVEDV and right ventricular ejection fraction (RVEF) within and between observers. Similarly, ICC values were stronger for axial as compared with short axis volumes and function-intraobserver RVEDV 0.99 (0.98-0.99) versus 0.96 (0.92-0.98) and RVEF 0.96 (0.93-0.98) versus 0.90 (0.82-0.95); interobserver RVEDV 0.97 (0.94-0.98) versus 0.90 (0.73-0.95) and RVEF 0.85 (0.53-0.94) versus 0.82 (0.67-0.90). Axially derived measurements of RV volumes and function have better agreement and reproducibility as compared with short axis values; whereas axial volumes tend to be larger, RVEF is not significantly different between the two methods.

Effect of Transcatheter Closure of Baffle Leaks Following Senning or Mustard Atrial Redirection Surgery on Oxygen Saturations and Polycythaemia

The aim of this study was to describe the clinical importance and methods of transcatheter closure of systemic venous baffle leaks after atrial redirection procedures for transposed great vessels. Until the late 1970s, atrial redirection surgery was the principal surgical palliative approach to manage transposed great vessels. Baffle leaks are among the many long-term complications of this type of surgery, and their prevalence increases over time. The clinical consequences of baffle leaks in this population are poorly understood, and the indications for closure are incompletely defined. During outpatient follow-up of 126 patients after atrial redirection surgery, 15 baffle leaks were detected in 11 patients. All underwent transcatheter closure using either an occluding device or a covered stent if there was concomitant baffle obstruction. The average age at the time of the procedure was 26 years (range 6 to 42). Ten of 11 patients were cyanosed at rest or on a simple walk test (median oxygen saturation level 80%, range 65% to 96%). Six of 11 patients were polycythemic before leak closure (median hemoglobin concentration 19 g/dl, range 13.8 to 23). After closure, there was a significant improvement in saturation (median 97%, p <0.0001) and a significant reduction in hemoglobin concentration at 6 months after the procedure (median 14.8 g/dl, p <0.05). There were no procedural adverse events. One patient experienced late device embolization necessitating surgical removal. In conclusion, transcatheter closure of baffle leaks is a technically feasible although frequently complex and lengthy procedure. Closure is associated with an improvement in oxygen saturations and a reduction in polycythaemia.

Equilibrium contrast cardiovascular magnetic resonance shows increased interstitial expansion in the systemic right ventricle of adults late after Mustard or Senning surgery for transposition of the great arteries

Summary In this study, we have used equilibium contrast CMR (EQ-CMR) to assess the interstium volume of patients after atrial redirection surgery, finding higher amounts than in healthy volunteers and correlations with known clinical markers of disease. Background After atrial redirection surgery (the Mustard and Senning operations) for transposition of the great arteries (TGA) the systemic right ventricle (RV) suffers from late systolic failure with resultant high morbidity and mortality. The mechanisms of late systemic RV failure are poorly characterised. We hypothesised that diffuse interstitial expansion representing diffuse fibrosis would be greater in the right ventricles of patients following Mustard or Senning surgery and that it would be associated with other markers of heart failure and disease severity in these patients. Methods

Optimal assessment of right ventricular function using cardiac magnetic resonance cine imaging after Mustard palliation for transposition of the great arteries

Background The most common cause of a systemic right ventricle is atrial redirection surgery (Mustard repair) in the setting of complete TGA. Decreased RVEF is common and is a predictor of morbidity and mortality. Cardiac magnetic resonance (CMR) cine imaging is the reference standard for assessment of right heart size and function. However, the optimal method of RV planimetry using CMR in patients with Mustard palliation for complete TGA remains unclear.

A hybrid form of cardiac resynchronisation therapy in patients with failing systemic right ventricles

Late systemic right ventricular (RV) dysfunction after atrial redirection surgery is common. Patients may require cardiac transplantation in early adulthood. We undertook cardiac resynchronisation (CRT)/defibrillator therapy in two patients as a bridge to transplantation. Two males (aged 24, 110 kg and 26 years, 106 kg); having undergone a Mustard procedure for dextro-transposition of the great arteries at 7 and 6 months of age respectively, presented with impaired systemic RV function and New York Heart Association III symptoms. Both patients had dual chamber pacemakers in-situ for sinus bradycardia. Upgrade to CRT was performed by conserving the existing endocardial leads and placement of epicardial electrodes. One demonstrated sustained improvement over a 24 month follow-up period. A hybrid CRT strategy is feasible in patients with failing systemic RVs and pre-existent endocardial dual chamber pacemakers. Appropriate patient selection criteria and optimum lead placement, however, still needs further evaluation in this population.

Non-contact mapping guided cardiac resynchronization therapy for a failing systemic right ventricle

Progressive systemic right ventricular (sRV) dysfunction, atrial and ventricular arrhythmias and sudden cardiac death are well-recognized late sequelae of atrial redirection surgery in which the right ventricle is left connected to the systemic circulation. Although cardiac resynchronization therapy (CRT) poses an attractive therapeutic option, little is known about indications, patient selection, and technical aspects of best lead placement. We undertook CRT in a 27-year-old female patient post-Mustard correction for d-transposition (d-TGA) with New York Heart Association (NYHA) grade III disability with QRS duration measuring 130 ms. There was also echocardiographic (TTE) evidence of severe sRV dysfunction. Non-contact mapping (NCM) was used to define sites of late activation within the sRV and the acute intra-arterial blood pressure (BP) response was assessed during implantation of a 4 french (F) lead onto the endocardial surface of the sRV. At 4 weeks post-implant sRV lateral wall motion had improved and the ejection fraction (EF) rose from 23 to 33%. The patient has been successfully anticoagulated and improved to NYHA II status after 6 months. The use of NCM proved safe and effective and provided a qualitative assessment of electrical viability of the sRV complimenting the measurement of mechanical function provided by TTE. The favourable clinical response in the above case justifies a prospective evaluation of this strategy.

Cardiac defibrillation therapy for at risk patients with systemic right ventricular dysfunction secondary to atrial redirection surgery for dextro-transposition of the great arteries

To review techniques of implantable cardioverter-defibrillators (ICD) in patients after Mustard surgery for arterial transposition. Retrospective analysis of all Mustard patients receiving ICDs at our institution. Five patients (median age 24 years, range 19-35, 3 male) with systemic right ventricular dysfunction (sRV) dysfunction and New York Heart Association (NYHA) II and III, received ICDs. Implantation was performed transvenously in three patients, epicardial patches and subcutaneous arrays at surgery in two patients. Two patients required lead extraction and baffle stent angioplasty before ICD implantation. Defibrillation vectors incorporating the anterior sRV mass [i.e., sub-pulmonary left ventricle (pLV) to generator can, and between epicardial defibrillator patches], consistently achieved a minimum 10 joule(J) safety margin during defibrillation threshold (DFT) testing. Subcutaneous arrays and endocardial vectors that included a superior vena cava (SVC) electrode were less effective. One patient developed pulmonary oedema post-procedure. At a median 20 months, all patients were alive and in NYHA class II. Follow-up over 24 months documented multiple non-sustained ventricular tachycardia (VT) in the group and one patient had recurrent VT with aborted device therapy. Defibrillator implantation in Mustard patients is challenging. Sub-optimal defibrillation should be anticipated and can be overcome using vectors which integrate the RV mass and high-energy devices. A staged procedure involving pre-implant interventions or separate DFT tests, where indicated, may be better tolerated by patients.