Repair of common arterial trunk: palliation and delayed correction as a viable alternative strategy in selected patients.

OBJECTIVES: Primary repair of common arterial trunk (CAT) is burdened by high mortality rates, especially in the presence of multiple risk factors. Timing, possible palliative methods, optimal management of associated cardiac lesions and handling of a poor preoperative state are still under discussion. METHODS: We retrospectively analysed all patients who underwent surgery for CAT in our institution between 2008 and November 2020. We included 22 patients, 11 of whom received primary correction (PC) and 11 of whom underwent initial palliation by partial repair, leaving the ventricular septal defect open and connecting the right ventricle to the pulmonary arteries with a small valveless right ventricle-to-pulmonary artery conduit. A delayed correction (DC) was performed after 11.5 ± 3.6 months. RESULTS: The overall operative mortality was 4.5%; 1 patient (affected by severe truncal valve stenosis and presenting in a poor state preoperatively) in the DC group died after palliation. The incidence of postoperative pulmonary hypertensive crisis was significantly higher in the PC group (P = 0.027). No patient from either group required postoperative extracorporeal support. Survival rates after 6 years differed slightly (PC group, 90%; DC group, 70%; log-rank = 0.270). CONCLUSIONS: PC of CAT remains an optimal surgical approach for patients with an expected low mortality. However, our data support palliation and DC as a suitable alternative strategy, especially in the presence of significant risk factors like interrupted aortic arch, poor preoperative condition or complex surgical anatomy.

Reduction of exposure to plasticizers in stored red blood cell units.

INTRODUCTION: Plastic can be toxic and hazardous to an organism's health, but it is being widely used in our daily lives. Di-2-ethylhexyl-phthalate is the most common plasticizer in medical devices made of polyvinylchloride and is commonly found in soft bags storing red blood cell units. Di-2-ethylhexyl-phthalate and its degradation product mono-2-ethylhexyl-phthalate can migrate into human body fluids, for example, blood and tissues. The aim of the study was to assess the concentration of plasticizers in red blood cell units according to storage time and after mechanical rinsing using a cell salvage device. METHODS: Levels of di-2-ethylhexyl-phthalate and mono-2-ethylhexyl-phthalate were analysed in 50 unwashed red blood cell units using liquid chromatography coupled with tandem mass spectrometry. In addition, phthalate concentrations were measured before and after mechanical rinsing in six more washed red blood cell units with storage times ranging between 36 and 56 days. A linear regression model was determined by the daily increase of di-2-ethylhexyl-phthalate and mono-2-ethylhexyl-phthalate in the stored red blood cell units subject to their storage time (range = 4-38 days), and the effect of mechanical rinsing on their phthalate concentration was calculated. RESULTS: A linear correlation was found between storage time of unwashed red blood cell units and the concentration of di-2-ethylhexyl-phthalate (p < 0.001) or mono-2-ethylhexyl-phthalate (p < 0.001). Stored red blood cell units older than 14 days had significantly higher concentrations of both contaminants than red blood cell units of shorter storage time (p < 0.001). Mechanical rinsing in washed red blood cell units attained a reduction in the di-2-ethylhexyl-phthalate and mono-2-ethylhexyl-phthalate concentration by a median of 53% (range = 18-68%; p = 0.031) and 87% (range = 68-96%; p = 0.031), respectively. CONCLUSION: Leaching of di-2-ethylhexyl-phthalate and mono-2-ethylhexyl-phthalate into red blood cell units depends on the duration of storage time. Plasticizers can be significantly reduced by mechanical rinsing using cell salvage devices, and thus, red blood cell units can be regenerated with respect to chemical contamination.

Deep hypothermic circulatory arrest or tepid regional cerebral perfusion: impact on haemodynamics and myocardial integrity in a randomized experimental trial.

OBJECTIVES: Organ protective management during aortic arch surgery comprises deep hypothermic (18°C) circulatory arrest (DHCA), or moderate hypothermia (28°C/ 'tepid') with regional cerebral perfusion (TRCP). The aim of this experimental study was to evaluate the effect of distinct organ protective management on hemodynamic performance and myocardial integrity. METHODS: Ten male piglets were randomized to group DHCA (n = 5) or TRCP (n = 5) group and operated on cardiopulmonary bypass (CPB) with 60 min of aortic cross-clamping. Blood gas analysis was performed throughout the experiment. Haemodynamic assessment was performed using a thermodilution technique before and after CPB. Myocardial biopsies were taken 2 h after CPB and evaluated using terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick-end labelling assay and western blot analysis. RESULTS: At reperfusion, levels of central venous saturation were significantly higher (P = 0.016) and levels of lactate significantly lower (P = 0.029) in the DHCA group. After CPB, thermodilution measurements revealed higher stroke volume and lower peripheral resistance in the TRCP group (P = 0.012 and 0.037). At the end of the experiment, no significant differences regarding laboratory and haemodynamic parameters were evident. All specimens showed enrichment of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick-end labelling-positive cells exclusively at the left ventricular subendocardium with no difference between groups and equal concentrations of cyclo-oxygenase-2. CONCLUSIONS: TRCP is associated with decreased peripheral resistance and higher stroke volume immediately after CPB. However, this beneficial effect is contrasted by signs of lower body hypoperfusion, which is expressed by lower central venous saturations and higher lactate levels. Distinct strategies of organ protection did not seem to affect apoptotic/necrotic and inflammatory changes in the left ventricular myocardium.

Comparable Cerebral Blood Flow in Both Hemispheres During Regional Cerebral Perfusion in Infant Aortic Arch Surgery.

BACKGROUND: Cerebral protection during aortic arch repair can be provided by regional cerebral perfusion (RCP) through the innominate artery. This study addresses the question of an adequate bilateral blood flow in both hemispheres during RCP. METHODS: Fourteen infants (median age 11 days [range, 3 to 108]; median weight, 3.6 kg [range, 2.8 to 6.0 kg]) undergoing RCP (flow rate 54 to 60 mL · kg-1 · min-1) were prospectively included. Using combined transfontanellar/transtemporal two- and three-dimensional power/color Doppler sonography, cerebral blood flow intensity in the main cerebral vessels was displayed. Mean time average velocities were measured with combined pulse-wave Doppler in the basilar artery, and both sides of the internal carotid, anterior, and medial cerebral arteries. In addition, bifrontal regional cerebral oximetry (rSO2) was assessed. Comparing both hemispheres, measurements were performed at target temperature (28°C) during full-flow total body perfusion (TBP) and RCP. RESULTS: A regular circle of Willis with near-symmetric blood flow intensity to both hemispheres was visualized in all infants during both RCP and TBP. In the left internal carotid artery, blood flow direction was mixed (retrograde, n = 5; antegrade, n = 8) during TBP and retrograde during RCP. Comparison between sides showed comparable cerebral time average velocities and rSO2, except for higher time average velocities in the right internal carotid artery (TBP p = 0.019, RCP p = 0.09). Unilateral comparison between perfusion methods revealed significantly higher rSO2 in the right hemisphere during TBP (82% ± 9%) compared with RCP (74% ± 11%, p = 0.036). CONCLUSIONS: Bilateral assessment of cerebral rSO2 and time average velocity in the main great cerebral vessels suggests that RCP is associated with near-symmetric blood flow intensity to both hemispheres. Further neurodevelopmental studies are necessary to verify RCP for neuroprotection during aortic arch repair.

Goal-directed-perfusion in neonatal aortic arch surgery.

Reduction of mortality and morbidity in congenital cardiac surgery has always been and remains a major target for the complete team involved. As operative techniques are more and more standardized and refined, surgical risk and associated complication rates have constantly been reduced to an acceptable level but are both still present. Aortic arch surgery in neonates seems to be of particular interest, because perfusion techniques differ widely among institutions and an ideal form of a so called "total body perfusion (TBP)" is somewhat difficult to achieve. Thus concepts of deep hypothermic circulatory arrest (DHCA), regional cerebral perfusion (RCP/with cardioplegic cardiac arrest or on the perfused beating heart) and TBP exist in parallel and all carry an individual risk for organ damage related to perfusion management, chosen core temperature and time on bypass. Patient safety relies more and more on adequate end organ perfusion on cardiopulmonary bypass, especially sensitive organs like the brain, heart, kidney, liver and the gut, whereby on adequate tissue protection, temperature management and oxygen delivery should be visualized and monitored.

Myocardial Protection During Aortic Arch Repair in a Piglet Model: Beating Heart Technique Compared With Crystalloid Cardioplegia.

BACKGROUND: Selective myocardial perfusion enables repair of congenital aortic arch obstruction without cardiac arrest. This study was inspired by the lack of prospective controlled studies of the beating heart (BH) technique compared with cold crystalloid cardioplegia (CC) regarding effects on myocardial performance, ischemic damage, and serum electrolyte levels. METHODS: In a prospective study, 20 male piglets weighing 11.1 ± 1.3 kg were operated on using cardiopulmonary bypass (CPB) and underwent 60 minutes of aortic cross-clamping. According to prospective randomization, myocardial protection included either a BH modification with selective myocardial perfusion using an individual roller pump or CC. Hemodynamic performance was evaluated by a conductance catheter technique before and after CPB and calculated in relation to baseline levels. Laboratory analysis included blood levels of troponin T and serum electrolytes. RESULTS: Eighteen piglets entered analysis. There were significantly higher slopes of end-systolic pressure-volume relations (168% ± 92% versus 89% ± 16%; p = 0.046) and preload-recruitable stroke work (PRSW) (139% ± 37% versus 103% ± 31%; p = 0.040) in BH piglets compared with those who underwent CC. Laboratory analysis during reperfusion revealed higher levels of troponin T (1.31 ± 0.28 ng/mL versus 0.49 ± 0.17 ng/mL; p < 0.01) and sodium (131 ± 4 mmol/L versus 120 ± 8 mmol/L; p = 0.003) and lower levels of potassium (4.8 ± 0.4 mmol/L versus 6.4 ± 1.0 mmol/L; p = 0.001) with BH compared with CC, whereas no significant differences were calculated at the end of the experiment. CONCLUSIONS: The BH technique is associated with improved contractility compared with standard CC. There is comparable ischemic damage in both groups, with an earlier rise in blood levels of troponin T after BH and more fluctuation of serum electrolytes with CC. Evidence of ischemic changes should dissuade one from using the BH technique imprudently.

Aortic arch obstruction neonates with biventricular physiology: left-open compared to closed inter-atrial communication during primary repair--a retrospective study.

BACKGROUND: Leaving an inter-atrial communication (IAC) open for left atrial decompression is often recommended in neonates with aortic arch obstruction undergoing primary repair. In this study, outcomes in these patients were compared to those with intact atrial septum after repair. METHODS: Between 2000 and 2013, 53 consecutive neonates with severe aortic arch obstruction (hypoplasia: n = 45, interruption: n = 8) underwent primary repair from an anterior approach. Median age and weight were 8 days (range: 2-30) and 3.2 kg (range: 2.4-4.4), respectively. Cardiac morphology included a ventricular septal defect (VSD, large: n = 28, small: n = 7), malposition of great arteries (n = 10), and severe left ventricular outflow tract obstruction (LVOTO, n = 10). During corrective surgery IAC was closed (group-I, n = 37) or partially left-open (group-II, n = 16). Primary endpoints were hospital death, and re-intervention (surgery and/or balloon) due to aortic arch re-coarctation or recurrent LVOTO. Statistically significant variables by univariate analysis were incorporated in the corresponding multivariable regression model. RESULTS: Regarding morphological discrepancies more patients in group-II presented with LVOTO (p = 0.05), or the combination of arch hypoplasia, intact ventricular septum and normal ventriculo-arterial connection (p = 0.017). Hospital mortality was 8.1% in group-I and 37.5% in group-II (p = 0.016). Re-intervention was performed in 13 patients (group-I: n = 6 vs. group-II: n = 7) due to aortic arch re-coarctation (n = 12) and/or recurrent LVOTO (n = 3), and resulted in a Kaplan-Meier freedom from re-intervention of 87 ± 6% and 79 ± 8% in group-I, and 64 ± 14% and 64 ± 14% in group-II after 1 and 5 years, respectively (p = 0.016). Multivariate analysis revealed LVOTO as an independent risk factor for hospital death (p = 0.042), whereas both LVOTO and left-open IAC (p = 0.001 and 0.01) were independent risk factors for re-intervention. CONCLUSIONS: A left-open IAC increases risk of re-intervention at the left heart aorta complex. Sustained left-to-right shunting on atrial level seems to induce preload reduction of the often restrictive left ventricle leading to decreased aortic blood flow.

Aortic Arch Reconstruction in Neonates with Biventricular Morphology: Increased Risk for Development of Recoarctation by Use of Autologous Pericardium.

BACKGROUND: The aim of this study was to analyze risk factors promoting development of recoarctation (Re-CoA) in neonates who survived aortic arch repair from an anterior approach. METHODS: Fifty consecutive neonates with biventricular morphology and ductal-dependent lower body perfusion who were discharged home following aortic arch repair with cardiopulmonary bypass between 2000 and 2012 were retrospectively reviewed. Arch anatomy was either interruption (n = 10) or hypoplasia with coarctation (n = 40). Aortic arch reconstruction was performed by using patch material (bovine pericardium, n = 30, homograft, n = 10, or glutaraldehyde-treated autologous pericardium, n = 7), and three patients underwent direct end-to-side anastomosis. Antegrade cerebral and continuous myocardial perfusion was performed in 39 and 21 patients, respectively. Kaplan-Meier freedom from Re-CoA was calculated. Morphologic and perioperative data indicating increased risk of Re-CoA by univariate analysis were included in multivariate Cox regression analysis. RESULTS: Mean follow-up was 5.3 ± 4.1 years. Re-CoA occurred in 13 patients and was treated successfully by balloon dilatation (n = 6) or surgery (n = 7). Freedom from Re-CoA after 1 and 5 years was 83 ± 5 and 79 ± 6%, respectively. Two patients died early after surgical repair of Re-CoA. The use of autologous pericardium for aortic arch augmentation was the only independent risk factor for development of Re-CoA (hazard ratio: 4.3 [95% confidence interval: 1.2-16.1]; p = 0.028). CONCLUSION: Re-CoA following neonatal aortic arch surgery can be treated by balloon dilatation or surgery, if adequate. In this study, the risk for development of Re-CoA was independently increased by the use of autologous pericardium during initial arch repair.

Improved contractility with tepid modified full blood cardioplegia compared with cold crystalloid cardioplegia in a piglet model.

OBJECTIVES: Experience regarding warm blood cardioplegia according to Calafiore results from its broad use in adult patients. In this experimental study, tepid (28°C) modified full blood cardioplegia (MBC) was adopted for paediatric use and compared with cold crystalloid cardioplegia (CCC). METHODS: Twenty male piglets (mean weight: 11.1 ± 1.0 kg) were operated on cardiopulmonary bypass (CPB) in moderate hypothermia (28°C) and randomized to MBC (n = 8) or CCC (n = 12) for 60 min aortic cross-clamping. Blood levels of myocardial proteins [N-terminal pro-brain natriuretic peptide (NT-pro-BNP), myoglobin, creatine kinase type MB and troponin-I] were investigated at the beginning of the experiment and after CPB. Haemodynamic measurements included thermodilution and conductance-catheter technique inserted through the left ventricle-apex. Pressure-volume loop analysis was performed with dobutamine-stress test and inflow occlusion, enabling preload independent evaluation of myocardial performance. Changes of measured data post-CPB were calculated in relation to baseline-levels (%). RESULTS: Baseline and operative data in both groups were similar. During the experiment, cardiac markers showed no significant variations between groups. Pressure-volume loop analysis during stress test revealed a significantly higher preload independent contractility (slope of end-systolic pressure-volume relation: Ees) with MBC compared with CCC (MBC: 123 ± 35% [confidence interval (CI95): 93-153] vs CCC: 78 ± 34% [CI95: 54-102]; P = 0.042), whereas cardiac output was not significantly different between groups {MBC: 122 ± 16% [95% confidence interval (CI95): 109-135] vs CCC: 105 ± 17% [CI95: 93-116]; P = 0.069}. CONCLUSION: This randomized animal study proves feasibility and safety of MBC for paediatric use. Haemodynamic evaluation and cardiac markers did not show inferiority to standard CCC. Moreover, MBC seems to be associated with superior contractility post bypass, which encourages us to use MBC in paediatric patients in the near future.

Troponin I levels in extracorporeal membrane oxygenation following congenital heart surgery.

BACKGROUND: Correlating postcardiotomy extracorporeal membrane oxygenation (ECMO) troponin I (TnI) levels and outcomes. METHODS: Between January 2006 and August 2010, 34 patients needed postcardiotomy ECMO for low cardiac output. Bailout ECMO was required either after unsuccessful weaning from bypass (n = 17, 50%), postoperatively from prolonged hemodynamic failure (n = 8, 23.5%), or following resuscitation (n = 9, 26.5%). The TnI levels were measured following surgery or resuscitation during 10 days and compared between survivors (group I) and non-survivors (group II). RESULTS: Median support duration was seven days (range: 0-31). Surgery involving hypoplastic aortic arch repair (Norwood palliation; n = 7, 20.6%, or biventricular repair; n = 11, 32.4%) led to most ECMO runs. Successful weaning from ECMO and hospital survival were 76.5% and 50%, respectively. In group I, peak TnI levels were reached by 24 hours postoperatively, comparable to levels in group II (36 ± 34 vs 49 ± 38 ng/mL; P = .98). However, in group II, TnI levels formed a plateau by the second postoperative day, whereas group I showed a steep decline in TnI levels, suggesting myocardial recovery (P = .028). All patients (n = 4) who reached or maintained peak TnI levels at 48 hours died. On days 8, 9 and 10, TnI levels were significantly higher in group II (P = .024, .019, and .013, respectively). CONCLUSIONS: Postcardiotomy ECMO was most commonly required after aortic arch repair. In the absence of ongoing myocardial insult due to ECMO hardware issues, coronary insufficiency or residual lesions, plateau TnI levels at 48 hours may seem to indicate an unfavorable outcome due to irreversible myocardial damage.

Mid-term experience with the Hancock porcine-valved Dacron conduit for right ventricular outflow tract reconstruction.

OBJECTIVES: Surgical reconstruction of the right ventricular outflow tract (RVOT) often requires implantation of a valved conduit. A single-centre 10-year experience with the Hancock porcine-valved Dacron conduit was retrospectively assessed. METHODS: The records of 63 patients who underwent RVOT reconstruction with Hancock conduit implantation between August 2000 and July 2010 were retrospectively reviewed. The median age was 13 years (range, 4 months to 64 years) and the median weight 44 kg (range, 6.5-75 kg). Fifty-one patients (83%) had previous cardiac surgery, and conduit replacement was performed in 31 patients (49%). Patient and conduit survivals with respect to factors precipitating conduit degeneration were analysed. Conduit failure was defined as severe conduit regurgitation or stenosis with a main pulmonary artery systolic gradient over 60 mmHg. RESULTS: Early mortality was 4.8% and not related to conduit failure. Follow-up was complete with a mean duration of 3.5 ± 2.6 years. Patient survival after conduit implantation was 93 [95% confidence interval (CI), 87-100], 90 (95% CI, 81-100) and 85% (95% CI, 74-98) after 1, 3 and 5 years, respectively. Conduit failure occurred in six patients after a median of 5.6 years (range, 2.7-9.0 years). Freedom from conduit failure was 100, 96 (95% CI, 89-100) and 83% (95% CI, 62-100%) after 1, 3 and 5 years, respectively. Mean systolic gradient over the stenotic conduit valve was 87 ± 11 mmHg. Neither RVOT-aneurysm formation nor distal conduit stenosis occurred. Univariate analysis revealed younger age and absent pulmonary valve syndrome as risk factors for conduit failure (P = 0.01 and P < 0.01). Stepwise logistic regression identified higher white blood cell count at postoperative day 8 as a significant risk factor for conduit failure (odds ratio, 0.7; 95% CI, 0.52-0.89; P < 0.01). CONCLUSIONS: The Hancock conduit is a valuable option for pulmonary valve replacement. It is not associated with RVOT-aneurysm formation or distal conduit stenosis. A persisting perioperative inflammatory reaction may be a predictor for later conduit failure.

Early failure of xenogenous de-cellularised pulmonary valve conduits--a word of caution!

OBJECTIVE: The longevity of valved right ventricle to pulmonary artery (RV-PA) conduits is limited due to calcification and degeneration of non-viable structures. Xenografts are commonly used because of the restricted availability of cryopreserved homografts. Tissue-engineered (de-cellularised) pulmonary valves (TEPVs) were thought to be a valuable alternative to cryopreserved pulmonary homografts due to postoperative seeding with viable autologous vascular endothelial cells. METHODS: From July 2007 to December 2008, xenogenous TEPV (Matrix P plus) were implanted in 16 patients in the right ventricular outflow tract for different indications, related to congenital heart disease. Mean age at operation was 14+/-11 years, including three patients younger than 1 year. The median conduit size was 22 mm (range: 13-26 mm). RESULTS: The early and late survival rates were 100%. At a median follow-up of 10 months (range: 2-17 months), six patients (38%) had to be re-operated upon due to obstructed grafts. Five of these patients were older than 13 years (range: 13-26 years); one patient was younger than 1 year. On echocardiography before re-operation, mean systolic gradient in the main PA was 66+/-18 mmHg. In explanted conduits, we found a predominantly peripheral conduit narrowing without leaflet calcification. Histological examination revealed stenosis formation, due to inflammatory infiltration and severely fibrogenic pseudo-intimal reaction. CONCLUSIONS: On the basis of our short-term results, the Matrix P plus de-cellularised tissue-engineered pulmonary valve cannot be regarded as an ideal conduit for right ventricular outflow tract reconstruction, as the widespread use of these grafts may increase the possibility of frequent early conduit failures.