Kristof Vandekerckhove

Reference Values for Echocardiographic Assessment of the Diameter of the Aortic Root and Ascending Aorta Spanning All Age Categories

Thoracic aortic dilatation requires accurate and timely detection to prevent progression to thoracic aortic aneurysm and aortic dissection. The detection of thoracic aortic dilatation necessitates the availability of cut-off values for normal aortic diameters. Tools to evaluate aortic dimension above the root are scarce and inconsistent regarding age groups. The aim of this study was to provide reference values for aortic root and ascending aortic diameters on the basis of transthoracic echocardiographic measurements in a large cohort of children and adults. Diameters at the level of the sinuses of Valsalva (SoV) and ascending aorta (AA) were assessed with transthoracic echocardiography in 849 subjects (453 females, age range 1 to 85 years, mean 40.1 ± 21.3 years) and measured according to published guidelines. Linear regression analysis was applied to create nomograms, as well as equations for upper limits of normal and z-scores. SoV and AA diameters were strongly correlated with age, body surface area (BSA), and weight (r = 0.67 to 0.79, p <0.001 for all). Male subjects had significantly larger aortic dimensions at all levels in adulthood, even after BSA correction (p ≤0.004 for all age intervals). Gender-, age-, and BSA-specific upper limits of normal and z-score equations were developed from a multivariate regression model, which strongly predicts SoV and AA diameters (adjusted R(2) for SoV = 0.84 and 0.67 and for AA = 0.82 and 0.74, for male and female subjects, respectively). In conclusion, this study provides widely applicable reference values for thoracic aortic dilatation screening purposes. Age, BSA, and gender must be taken into account when assessing an individual patient.

Pleural effusions, water balance mediators and the influence of lisinopril after completion Fontan procedures

OBJECTIVE To investigate whether the duration of pleural drainage after Fontan completion operations can be influenced by postoperative lisinopril administration or can be related to water balance hormone levels. METHODS In a prospective trial 21 patients scheduled for total cavopulmonary connection were randomized into two groups, with group I receiving lisinopril postoperatively, and group II receiving no angiotensin converting enzyme inhibitor. Plasma levels of antidiuretic hormone, renin and aldosteron were analyzed preoperatively and at four-time points postoperatively. Groups were comparable for age, preoperative saturation and pulmonary pressure, cardiopulmonary bypass time, cross-clamp time and preoperative hormone levels. RESULTS Mean duration of pleural drainage was comparable for both groups (group I: 9.6+/-8 days vs group II: 10+/-7 days; p=0.78). The hormone profiles in each group changed significantly at 1 and 24h postoperatively compared to preoperative values (p<0.05), with no significant differences between the treatment groups. The duration of pleural drainage correlated significantly with hormone levels at 24h postoperatively, and with longer bypass times. At multivariate analysis only aldosteron and antidiuretic hormone level at 24h came out as factors reaching significance for prolonged pleural drainage. CONCLUSIONS The Fontan completion induces significant changes in the levels of antidiuretic hormone, aldosteron and renin. Prolonged drainage correlates significantly with elevated levels of aldosteron, renin and antidiuretic hormone postoperatively, and with longer bypass time, but is not influenced by lisinopril. The eventual adjunct therapy with aldosteron antagonists warrants further study.

Disease-specific outcome analysis of palliation with the modified Blalock-Taussig shunt.

Background: Albeit being a simple surgical procedure, adverse outcomes with the modified Blalock-Taussig shunt (MBTS) are commonly reported in generalizing terms, independent of the underlying heart disorder. Methods: From August 1995 to December 2013, a total of 150 children underwent an MBTS for tetralogy of Fallot (TOF; n = 44, 29%), pulmonary atresia with ventricular septal defect (PA/VSD; n = 28, 19%), pulmonary atresia with intact ventricular septum (PA/IVS; n = 17, 11%), transposition of the great arteries with ventricular septal defect (TGA/VSD) with pulmonary stenosis (PS; n = 12, 8%), Ebstein malformation (n = 2, 1%), and complex univentricular anomalies (n = 47, 31%). Outcome analysis focused on operative mortality and survival until shunt takedown, adjusted to the underlying disease. Results: In-hospital mortality was 8.7% (n = 13), and interstage mortality was 5.1% (n = 7), resulting in 86.1% survival to the next surgery. Hospital mortality was 14% in PA/VSD, 13% in univentricular heart, and 18% in PA/IVS, while no mortality was observed in TOF, TGA/VSD/PS, and Ebstein disease. A shunt-related complication was observed in 18% (n = 27) of the children, including acute thrombosis (n = 7, 5%), shunt stenosis (n = 3, 2%), overshunting (n = 7, 5%), and pulmonary artery stenosis (n = 10, 7%). Multivariate analysis of shunt-dependent time survival identified a shunt complication occurring in a univentricular circulation (hazard ratio [HR] 4.10, 95% confidence interval [CI] = 1.05-17.43, P = .01) and increased shunt size-to-weight ratio (HR 2.72, 95% CI = 0.80-9.18, P = .04) as risk factors. Shunt thrombosis was also a negative outcome predictor in PA/VSD, when requiring associated unifocalization (P = .05). Conclusion: This study shows that the outcome of palliation with the MBTS is importantly affected by the occurrence of a shunt-related complication, whose circulatory effect is even more dismal in single ventricle hearts. Since an increased shunt size-to-weight ratio additionally compromises the shunt-dependent survival, it emphasizes that the choice of the shunt with regard to size as well as surgical approach remains critical.

Univentricular heart and Fontan staging: analysis of factors impacting on body growth

OBJECTIVES The optimal timing of the Fontan staging for a univentricular heart and its impact on growth remains debateable. In a Fontan cohort, the influence of staged interventions and patient factors on somatic development was explored. METHODS We reviewed 64 total cavopulmonary connection (TCPC) patients treated since 1992. Serial anthropometric parameters recorded from birth to the latest follow-up (mean 12.5 ± 6.1 years) and at each intervention [neonatal surgery, bidirectional cavopulmonary anastomosis (BCPA), TCPC, catheter treatment] were converted to z-scores. The influence of saturation, heart failure treatment and surgery intervals on growth was determined. RESULTS The mean z-scores for weight and height changed significantly at each surgery up to the TCPC (-0.3 ± 1.2 and 0 ± 1 at birth, -1.3 ± 1.9 and -0.9 ± 1.7 at neonatal surgery, -2.1 ± 1.2 and -1.6 ± 1.3 at the BCPA, -1.2 ± 1.3 and -0.7 ± 1.4 at the TCPC for weight and height, respectively; P < 0.05 for each interval), with the largest decline before the BCPA, and the most marked improvement before the TCPC. Z-scores did not change significantly after the TCPC. Younger age at the BCPA had a positive influence on the weight z-score at the TCPC (P < 0.05); somatic growth at the latest follow-up (FU) was negatively influenced by heart failure treatment (P < 0.05). CONCLUSIONS Body growth is severely impaired in Fontan patients. A close interstage follow-up between the first surgery and the BCPA must be targeted at optimizing nutritional support to counter the important growth retardation occurring before the BCPA. The better catch-up growth at the TCPC when the BCPA is performed earlier in life supports the current trend to perform the BCPA at a younger age. Heart failure treatment after a Fontan completion is independently associated with decreased late somatic development.

Functional analysis of the anatomical right ventricular components: should assessment of right ventricular function after repair of tetralogy of Fallot be refined?

OBJECTIVE Follow-up after tetralogy of Fallot (ToF) repair is directed to detect timely right ventricular (RV) dysfunction by following pulmonary regurgitation and global RV size, with little attention for the effective contribution of regional RV dysfunction. This study investigates the contribution of regional RV dysfunction on exercise capacity after ToF repair. METHODS Forty-two patients were investigated with cardiac magnetic resonance imaging for regional RV dysfunction in relation to global RV function by functional quantification of the sinus and outflow part of the RV. The impact of regional and global RV dysfunction on clinical status was studied by exercise testing. RESULTS Global RV function was lower than sinus function (ejection fraction (EF) 52±12% vs 58±10%, P<0.001), attributable to the adverse influence of right ventricular outflow tract (RVOT) dysfunction (EF 34±17%). Percent predicted peak VO2 correlated better with the RV sinus ejection fraction compared with the global RV ejection fraction (r=0.51, P=0.001 vs r=0.44, P=0.004). Multivariate analysis revealed the EF of RV sinus (β=0.34, 95% CI 0.07-0.61, P=0.013) and the extent of RVOT akinesia (β=-0.28, 95% CI -0.50; -0.06, P=0.015) as significant determinants of exercise capacity. Impaired exercise performance occurred in 43% of the patients, and was independently determined by the type of repair (transventricular vs transatrial: OR 6.0, 95% CI 1.31-17.3, P=0.02) by associating greater sinus and RVOT dysfunction. CONCLUSION Functional analysis of the RV components shows that exercise capacity after repair of ToF is better predicted by systolic function of the RV sinus as the extent of RVOT dysfunction commonly leads to underestimation of global RV function. This method of differential quantification of regional RV function might be more appropriate than assessment of global RV function during the long-term follow-up of repaired ToF patients.

The fate of the aortic root after early repair of tetralogy of Fallot

OBJECTIVE Late aortic root dilatation is a growing concern in patients operated on for tetralogy of Fallot (ToF). This longitudinal follow-up study sought to evaluate the changes in the aortic root dimensions in relation to body growth, assuming that early repair of tetralogy of Fallot might prevent late aortic dilatation. METHODS A retrospective analysis of the aortic root dimensions was performed in 88 patients repaired early for tetralogy of Fallot by echocardiographic measurement of aortic annulus, sinus of Valsalva and sinotubular junction, adjusted for body surface area and expressed as z-scores. Mean age at repair was 9.7 + or - 7.4 months. Median age was 7.3 months (range 45 days-29 months). RESULTS At the time of repair, all root dimensions were enlarged: z-score of the annulus 3.32 + or - 1.66; sinus 3.54 + or - 1.49; sinotubular junction 2.74 + or - 1.19. Within a mean follow-up of 6.9 + or - 4.4 years, the mean z-scores of both annulus and sinotubular junction significantly decreased to normal size at 7 years postoperatively: z-score of annulus 0.95 + or - 0.7 (p=0.006), z-score of sinotubular junction 0.99 + or - 1.47 (p=0.006). The z-score of the aortic sinuses appeared to regress slower to 2.78 + or - 1.26 (p=0.262). The indexed sinus diameter however regressed significantly from a mean of 51.4 + or - 13.4 mmm(-2) at correction to 28.9 + or - 7.2 mmm(-2) (p=0.0001) at latest follow-up. Evolution of aortic root size after repair was independent of aortic arch side, sex, age at repair or previous shunt palliation. CONCLUSIONS The initially dilated aortic root in tetralogy of Fallot normalises in size at the level of the annulus and sinotubular junction within 7 years after early repair. This process seems delayed at the level of the aortic sinuses, although the indexed root diameter shows significant regression over time. These results suggest that early repair of ToF abrogates the enlargement of the aortic root, validating one aspect of the need for tetralogy correction at a young age.

Role of myocardial hypertrophy on acute and chronic right ventricular performance in relation to chronic volume overload in a porcine model: relevance for the surgical management of tetralogy of Fallot.

OBJECTIVES The age for correction of tetralogy of Fallot has progressively declined to the postnatal period, often despite an increased rate of transannular patch repair. However, the long-term effect of premature exposure to chronic pulmonary insufficiency on the right ventricle remains unknown. On the basis of the relationship between the duration of pressure overload and age, the role of previous pressure load-related hypertrophy on right ventricular (RV) performance after chronic volume overload was investigated in a porcine model. METHODS RV hypertrophy (RVH), induced by pulmonary artery banding, was studied in pigs with (RVH plus pulmonary insufficiency [PI]) and without (RVH) subsequent PI. The effect of volume overload was compared between these 2 groups and pigs without RVH but with PI and controls (sham). Both acute and chronic effects on RV function were studied using conductance technology and validated using echocardiography. RESULTS After chronic volume overload, the end-systolic and end-diastolic volumes were smaller in the RVH+PI group than in the PI group, including a lower pulmonary regurgitation fraction (25% ± 5% vs 35% ± 5%; P = .002). RVH resulted in better preserved systolic function, confirmed by an increased preload recruitable stroke work slope (14.7 ± 1.8 vs 9.3 ± 1.3 Mw.s/mL; P = .025) and higher RV ejection fraction (51% ± 3% vs 45% ± 4%; P = .05). Myocardial stiffness was impaired in the RVH+PI group versus the PI group (β, 0.19 ± 0.03 vs 0.12 ± 0.02 mL(-1); P = .001), presenting restrictive physiology only in the condition associating RVH and PI. CONCLUSIONS The results of the present study have demonstrated that RVH attenuates the RV remodeling process related to chronic PI. It enables better preservation of contractility but at the cost of sustained diastolic impairment. These findings might help to determine the timing and strategy for repair of tetralogy of Fallot when RV outflow tract morphology indicates a definite need for transannular reconstruction.

Dilated cardiomyopathy caused by a novel TNNT2 mutation-added value of genetic testing in the correct identification of affected subjects.

Diagnosing familial dilated cardiomyopathy requires careful family history taking and clinical evaluation in first degree relatives. Based on the results of these findings the diagnosis may be established in the proband. However, due to the age-dependent expression of the disease, doubt may persist regarding the exact status of other family members, especially in young individuals. Here we present a family with DCM in whom we identified an underlying cardiac troponin T (TNNT2) mutation. Genetic testing was essential for the detection of asymptomatic carriers as well as for exclusion of the disease in other family members.

Increased aortic stiffness in prepubertal girls with Turner syndrome

BACKGROUND Aortic dilation and dissection contribute highly to the increased mortality of Turner syndrome (TS) but the exact pathophysiology is not completely understood. DESIGN Prospective case - control study. METHODS 15 prepubertal TS girls (median age 10.64, IQ 8.31-11.04) with a tricuspid (TAV, n=9) or a bicuspid (BAV, n=6) aortic valve, and 31 sex-, age-, and height-matched healthy controls underwent a cardiac and vascular ultrasound to evaluate aortic dimensions and elastic properties of the aortic wall. RESULTS TS BAV had significantly larger ascending aortic diameters than controls for absolute diameter, 22.2±5.1mm vs. 18.6±1.9mm (p=0.014) and z-score 1.7±2.1 vs. 0.1±0.7 (p=0.008). Distensibility of the ascending aorta was lower in the TS than in controls (40.2×10-3kPa-1, IQ 31.3-56.2 vs. 62.9×10-3kPa-1, IQ 55.5-76.5, p=0.003), both for TS TAV (p=0.014) and BAV (p=0.005). Stiffness index was higher in TS than in controls (5.26, IQ 3.34-5.26 vs. 3.23, IQ 2.55-3.24, p=0.005), both for TS TAV (p=0.028) and TS BAV (p=0.006). Pulse wave velocity was not different between groups. There was no correlation between stiffness and z-score of the ascending aortic diameter. CONCLUSIONS In prepubertal TS girls, stiffness of the ascending aorta is increased in patients with a BAV and TAV while dilation of the ascending aorta is more frequent in BAV. This suggests an intrinsic aortic wall abnormality making all TS patients at increased risk for severe aortic complications although the risk is the highest for TS with BAV.

Current outcomes of the bi-directional cavopulmonary anastomosis in single ventricle patients: analysis of risk factors for morbidity and mortality, and suitability for Fontan completion

OBJECTIVES The bi-directional cavopulmonary anastomosis forms an essential staging procedure for univentricular hearts. This review aims to identify risk factors for morbidity, mortality, and suitability for Fontan completion. METHODS A total of 114 patients undergoing cavopulmonary anastomosis between 1992 and 2012 were reviewed to assess primary - mortality and survival to Fontan completion - and secondary outcome endpoints - re-intubation, new drain, and ICU stay. Median age and weight were 8 months and 6.9 kg, respectively. In 83% of patients, 1-3 interventions had preceded. Norwood-type procedures became more prevalent over time. RESULTS Extubation occurred after a median of 4 hours, median ICU stay was 2 days; 10 patients (8.8%) needed re-intubation and 18 received a new drain. Higher central venous pressure and transpulmonary gradient were risk factors for new drain insertion (p<0.01). Higher pre-operative pulmonary pressure correlated with increased inotropic support and prolonged intubation (p=0.01). Need for re-intubation was significantly affected by younger age at operation (p=0.01). Hospital and pre-Fontan mortality were 11.4 and 5.3%, respectively. Operative mortality was independently affected by younger age (p=0.013), lower weight (p=0.02), longer bypass time (p=0.04), and re-intubation (p=0.004). Interstage mortality was mainly influenced by moderate ventricular function (p=0.03); 82% of survivors underwent or are candidates for Fontan completion. CONCLUSION The cavopulmonary anastomosis remains associated with adverse outcomes. Age at operation decreases with rising prevalence of complex univentricular hearts. Considering the important impact of re-intubation on hospital mortality, peri-operative management should focus on optimising cardio-respiratory status. Once this selection step is taken, successful Fontan completion can be expected, provided that ventricular function is maintained.