Outcomes of aortic valve repair in children stratified by complexity: Which outcome for which lesion?

OBJECTIVE

Aortic valvuloplasty frequency has significantly increased over the past 15 years. Surgical repair varies in complexity depending on valvular lesions. Our aim is to report results on the whole spectrum of aortic valvuloplasty techniques.

METHODS

All children who consecutively underwent aortic valvuloplasty for aortic stenosis and/or aortic insufficiency between January 2006 and December 2020 at Necker Sick Children's Hospital (Paris, France) were included in a retrospective cohort study. Aortic valvuloplasty techniques were classified into 3 difficulty levels: (1) simple repair, corresponding to commissurotomy and/or shaving in aortic stenosis (AS) in neonates (group 1) and children >1 month (group 2); (2) intermediate-complexity repair, corresponding to commissuroplasty, leaflet resuspension, and fenestration closure in aortic insufficiency (leaflet prolapse in connective tissue disease, isolated leaflet prolapse and Laubry-Pezzi groups); and (3) complex repair requiring a pericardial patch to restore a functional aortic valve in mixed aortic valve disease (bicuspidization with neocommissure and cusp extension groups).

RESULTS

During the study period, 324 children underwent aortic valvuloplasty. Survival and freedom from aortic valve reintervention at 10 years were, respectively, 86.1% and 50.9% in neonates with AS, 95.2% and 71.7% in children >1 month with AS, 93.8% and 79.5% in leaflet prolapse in connective tissue disease, 97.7% and 91.9% in isolated leaflet prolapse, 100% and 88% in those with Laubry-Pezzi syndrome, 97.4% and 84.8% in bicuspidization with neocommissure, and 100% and 54.2% in the cusp extension.

CONCLUSIONS

Durability of aortic valvuloplasty techniques is satisfactory and offers the possibility to delay the Ross procedure, regardless of the lesion's complexity.

Long-term results after the réparation à l'étage ventriculaire procedure for transposition of the great arteries and double-outlet right ventricle with pulmonary stenosis

OBJECTIVES

The purpose of this study is to describe the long-term results of the 'réparation à l'étage ventriculaire' (REV) technique for double-outlet right ventricle and transposition of the great arteries (TGA) with pulmonary stenosis (PS).

METHODS

Between 1980 and 2021, 157 patients underwent a REV procedure (median age and weight: 20.8 months and 7.7 kg). The most frequent anatomical presentation was the association between TGA, ventricular septal defect and PS (n = 116, 73.9%).

RESULTS

Sixty-seven patients (42.7%) underwent a Rashkind procedure, and 67 patients (42.7%) a prior surgical palliation (including 62 systemic-to-pulmonary artery shunts). Resection of the conal septum and/or ventricular septal defect enlargement was performed in 109 patients (69.4%). Thirteen patients (8.3%) died, including 4 during the first postoperative month and 2 after heart transplant. Overall survival at 40 years was 89.3%. Thirty-seven patients (23.6%) required 68 reinterventions on the right ventricular outflow tract (RVOT), including 49 reoperations, with a median delay of 9 years after the REV (8 months to 27 years). Twenty patients (12.7%) underwent RVOT valvulation (16 surgical and 4 interventional). Freedom from RVOT reintervention and reoperation at 40 years were 60.3% and 62.6%, respectively. Four patients (2.5%) required reoperation for left ventricular outflow tract obstruction, with a median delay of 4.8 years.

CONCLUSIONS

The REV procedure is a good alternative for TGA and double-outlet right ventricle with PS patients. Only a quarter of the patients required redo surgery on the RVOT. Reoperations for left ventricular outflow tract obstruction are scarce.

Outcomes of coronary artery obstructions after the arterial switch operation for transposition of the great arteries

OBJECTIVE

Coronary obstruction is a rare but common complication of the arterial switch operation for transposition of the great arteries. The majority of patients remain asymptomatic and no risk factors allow targeting for reinforced surveillance. We aim to review the natural history of patients diagnosed with coronary obstruction after arterial switch operation for transposition of the great arteries and occurrence of coronary-related outcomes.

METHODS

We retrospectively reviewed medical records of the 102 patients diagnosed with coronary obstruction after arterial switch operation for transposition of the great arteries in our institution from 1981 to 2022. Outcomes were anti-ischemic treatment introduction, revascularization (surgical or percutaneous angioplasty), and death; investigations that motivated revascularization were also reviewed.

RESULTS

Twenty-eight out of 102 patients presented with myocardial ischemia during the immediate postoperative phase, 31 were diagnosed when symptomatic, and 43 were identified at the presymptomatic stage, according to our screening policy in preschool-aged children. Stenosis-related event occurrence was, respectively, 29 out of 31 and 32 out of 43 in the latter 2 subgroups. Coronary-related mortality reached 10% in patients diagnosed when symptomatic; no patients died in the presymptomatic subgroup. Of the 28 low-risk patients with no signs of ischemia at diagnosis, 10 developed obstruction warranting reintervention during follow-up. Revascularization was motivated by appearance of symptoms in patients with severe stenosis in normal coronary dispositions, and by clinical symptoms or documented silent ischemia in abnormal coronary patterns.

CONCLUSIONS

Occurrence of stenosis-related events remains significant in patients after arterial switch operation, underlining the importance of early diagnosis for timely intervention. Initial anatomical evaluation identifies stenotic and at-risk patients; this will require periodical function testing. Follow-up modalities can be tailored to a patient's individual anatomic characteristics.

Outcomes after aortic coarctation repair in neonates weighing less than 2000 g

BACKGROUND

Preterm birth is common in children with congenital heart disease. However, data on how to manage low-birth-weight infants with aortic coarctation are scarce and outcomes are poorly reported. Surgery is often delayed in these infants because gaining weight is supposed to improve mortality and to reduce the risk for recoarctation.

METHODS

All infants weighing less than 2000 g who underwent repair for aortic coarctation at our institution between January 2017 and December 2020 were included in a retrospective study. Baseline characteristics, medical and surgical management, and outcomes, including recoarctation, death, and complications of preterm birth, were analyzed.

RESULTS

A total of 15 patients had coarctation repair at a median age of 15 days and at a median weight of 1585 g. Infants with a birth weight <1200 g were operated on later and did not have higher recoarctation rates compared to those with a birth weight >1200 g. The recoarctation rate was 26.6% and one infant died of an extracardiac cause. Concerning prematurity-related complications, we observed 40% of bronchopulmonary dysplasia, 40% of intraventricular hemorrhage, and 27% of retinopathy of prematurity. These complications were more prevalent in children with a birth weight of <1200 g.

CONCLUSION

Delaying surgery beyond 15 days to gain weight does not appear to decrease the risk of recoarctation and may be deleterious in low-birth-weight infants who are exposed for a longer period to risk factors of prematurity-related complications.

Congenital disconnection of the pulmonary arteries

OBJECTIVES

Disconnected pulmonary artery (PA) is a rare anomaly that can be isolated or associated with complex intracardiac malformations. Early reimplantation of the disconnected PA is recommended to allow growth and satisfactory pulmonary perfusion while preventing collateral artery development. The aim of this study was to describe the characteristics of patients with disconnected PA and, for those who had surgical reimplantation, to determine the incidence, delay and predictive factors of reintervention for reconnected PA stenosis.

METHODS

We include patients with the diagnosis of congenitally disconnected PA and surgical repair at our institution.

RESULTS

Retrospective observational study of 55 patients with a disconnected PA. Fifty-one underwent surgical correction and were followed up at our institution between 2000 and 2022. Disconnected PAs were observed in isolation in 31% of the cases. The most frequent form was left PA originating from the arterial duct (58%). The reimplantation was done at the median age of 12 days. Anastomotic stenosis was observed during follow-up in 71% of the patients with 75% of them requiring reintervention (55% of the population). The median delay to reintervention was 3.2 years after reimplantation, and >25% of reinterventions on the reimplanted PA occurred within the first postoperative year. We found more reintervention if associated cardiac defect, without significant statistic difference. Weight at re-confluence, presence of ductal tissue at the origin of the PA and prior shunt placement on the disconnected PA were not found to be risk factors for reintervention.

DISCUSSION

After surgical reimplantation of PA, >50% of patients required reintervention for PA stenosis. Technical improvements should be sought to reduce the incidence of this complication.

Transcatheter patent arterial duct closure in premature infants: A new technique to ease access to the patent arterial duct, with particular benefit for the tricuspid valve

BACKGROUND

Transcatheter patent arterial duct (PAD) closure in premature infants has been shown to be feasible. Since our early transcatheter PAD closure procedures in premature infants at Hôpital Necker Enfants Malades, we have changed our technique several times to advance the guidewire through the right heart to avoid tricuspid valve damage.

AIM

To describe the technique we have been using since May 2019, to report our results with a particular focus on tricuspid leaks and to analyse the potential mechanisms of tricuspid lesion development with previous methods.

METHODS

All premature infants weighing<2kg who underwent transcatheter PAD closure with this new technique were included. Demographic data, procedural data, outcome and procedural complications were reviewed, with particular attention to the occurrence of tricuspid regurgitation.

RESULTS

Between May 2019 and May 2020, 33 patients were included. Median gestational age was 25 weeks. Median birth weight and procedural weight were 690g (range 490-1065g; interquartile range [IQR] 620-785g) and 1160g (range 900-1900g; IQR 1030-1300g), respectively. Median age at procedure was 35 (IQR 30-46) days. PAD anatomy was evaluated on transthoracic echocardiography only. The median duct diameter was 3 (IQR 2.5-3.2) mm at the pulmonary end. Success rate was 100% (defined as successful closure without residual shunt). One patient had a renal vein thrombosis, which fully resolved with low-molecular-weight heparin anticoagulation. No tricuspid regurgitation or stenosis of the left pulmonary artery or the aorta was seen. One patient died of a superior caval vein obstruction with bilateral chylothorax related to a central catheter thrombosis 56 days after the procedure, unrelated to the catheter procedure.

CONCLUSION

In this prospective study, we describe a new technique to avoid tricuspid valve damage and facilitate delivery of the PAD device.

Anomalous aortic origin of coronary arteries: an alternative to the unroofing strategy

OBJECTIVES

Anomalous aortic origin of a coronary artery (AAOCA) is the second leading cause of sudden death in children and young adults. The most threatening anatomy is an interarterial and an intramural course, both probably involved in ischaemic phenomena and sudden death. The treatment of interarterial AAOCA remains controversial. Most of the published studies describe the results of the unroofing technique. Our study aims to evaluate the results of a different surgical approach.

METHODS

From 2005 to 2019, 61 patients were operated on for an interarterial AAOCA (median age 14.7 years). Forty patients had a right AAOCA, and 21 patients had a left AAOCA including 5 patients with intraseptal course. Seventy percent of patients were symptomatic. Five patients had an aborted sudden cardiac death. Two surgical techniques were used: an 'anatomical' repair for 35 patients (15 left and 22 right AAOCA) or a coronary translocation with creation of a neo-ostia in 19 patients (1 left and 18 right AAOCA). The 5 left AAOCA patients with an intra-septal course required a complete release of the coronary artery from the septum.

RESULTS

There was no early or late postoperative death. Three patients had an acute postoperative ischaemic event. Two patients required immediate angioplasty and stenting: 1 patient (7 years) with a hypoplastic right AAOCA and 1 patient (66 years) for inadequate tailoring after septal release. The third patient required an immediate surgical revision (H-2) for left AAOCA thrombosis at the level of the pericardial patch with full myocardial recovery at discharge. During follow-up, 1 patient with right AAOCA translocation and chronic chest pain required subsequent stenting and finally a coronary artery bypass grafting 2 years after initial surgery. One patient who had an asymptomatic mild right coronary stenosis 1 year after anatomical repair was successfully treated by angioplasty alone. All patients but 1 who underwent coronary translocation are totally asymptomatic. All patients with anatomical repair or septal release are free from ischaemic symptoms.

CONCLUSIONS

Anatomical repair might provide a better protective option for these patients. Unlike unroofing, it treats the entire intramural segment, relocates the ostium at the appropriate sinus level and corrects any acute take-off angle.

Ross procedure or complex aortic valve repair using pericardium in children: A real dilemma

OBJECTIVE

Difficult to repair aortic valve lesions, requiring the use of a valve substitute, remain controversial in the face of the Ross procedure, despite undeniable technical advances. This study was undertaken to compare midterm outcomes of children treated using the Ross procedure or aortic valvuloplasty for complex aortic valve lesions.

METHODS

Between January 2006 and December 2017, 126 patients aged younger than 18 years were treated for complex aortic stenosis and/or aortic insufficiency and were included in this retrospective study. Only aortic valve lesions requiring repair with an autologous or heterologous pericardial patch were considered complex lesions. Propensity score framework analyses were used to compare outcomes of the Ross and aortic valvuloplasty groups while controlling for confounders.

RESULTS

Among the 126 patients with complex aortic valve lesions, propensity score matching selected 34 unique pairs of patients with similar characteristics. Survival (aortic valvuloplasty, 94.1%; Ross, 91%; P = .89), freedom from overall reintervention (aortic valvuloplasty, 50.1%; Ross, 69%; P = .32), and freedom from infective endocarditis at 8 years (aortic valvuloplasty, 100%; Ross, 85.9%; P = .21) were similar. However, freedom from reintervention in the left ventricular outflow tract at 8 years was lower after aortic valvuloplasty than after the Ross procedure (50.1% vs 100%, respectively; P = .001).

CONCLUSIONS

Aortic valvuloplasty and the Ross procedure yielded similar 8-year outcomes regarding death, reoperation, and infective endocarditis although aortic valvuloplasty tended to be associated with fewer cases of infective endocarditis. Aortic valvuloplasty using a pericardial patch can be chosen as a first-line strategy for treating complex aortic valve lesions and might offer the possibility of a later Ross procedure.

The effect of lockdown on intentional and nonintentional injury during the COVID-19 pandemic in Cape Town, South Africa: A preliminary report

In response to the coronavirus pandemic, lockdown restrictions and a ban on alcohol sales were introduced in South Africa. Objectives. To investigate the impact of lockdown measures on the number of patients who visited a tertiary urban trauma centre. Methods. The period of investigation was from 1 February to 30 June 2020 and was segmented into three intervals: pre-lockdown (February and March 2020), hard lockdown (April and May 2020) and immediately post lockdown (June 2020). The electronic HECTIS health record registry was interrogated for the total number of patients that were seen per month. These were further categorised according to mechanism of injury (stab, gunshot, blunt assault and road traffic injuries). Penetrating (stab and gunshot) and blunt assault victims were collectively grouped as violent trauma. Results. The mean total number of patients seen decreased by 53% during the hard lockdown period. There was a moderate reduction (15%) in patients with gunshot injuries seen during the hard lockdown phase, but there was an 80% increase in the post-lockdown period. The proportion of patients injured in road traffic collisions pre lockdown, hard lockdown and immediate post lockdown was 16.4%, 8.9% and 11.1%, respectively. Patients injured in road traffic collisions decreased by 74% during the hard lockdown period and maintained a reduction of 32% during the immediate post-lockdown period. The mean total number of patients who visited the trauma unit returned to pre-lockdown levels in June. Conclusions. There was an overall trend of reduced number of patients who visited the trauma unit during the hard lockdown period; however, these numbers returned to pre-lockdown levels during the immediate post-lockdown period. The number of road traffic injury admissions remained reduced during all three phases of lockdown, while the number of gunshot victims increased substantially during the post-lockdown period.

Outcomes after common arterial trunk repair: Impact of the surgical technique

OBJECTIVES

We compared the risk of mortality and reintervention after common arterial trunk (CAT) repair for different surgical techniques, in particular the reconstruction of the right ventricle outflow tract with left atrial appendage (LAA) without a monocusp.

METHODS

The study population comprised 125 patients with repaired CAT who were followed-up at our institution between 2000 and 2018. Statistical analysis included Cox proportional hazard models.

RESULTS

Median follow-up was 10.6 years. The 10-year survival rate was 88.2% (95% confidence interval [CI], 80.6-92.4) with the poorest outcome for CAT type IV (64.3%; 95% CI, 36.8-82.3; P < .01). In multivariable analysis, coronary anomalies (hazard ratio [HR], 11.63 [3.84-35.29], P < .001) and CAT with interrupted aortic arch (HR, 6.50 [2.10-20.16], P = .001) were substantial and independent risk factors for mortality. Initial repair with LAA was not associated with an increased risk of mortality (HR, 0.37 [0.11-1.24], P = .11). The median age at reintervention was 3.6 years [7.3 days-13.1 years]. At 10 years, freedom from reintervention was greater in the group with LAA repair compared with the valved conduit group, 73.3% (95% CI, 41.3-89.4) versus 17.2% (95% CI, 9.2-27.4) (P < .001), respectively. Using a valved conduit for repair (HR, 4.79 [2.45-9.39], P < .001), truncal valve insufficiency (HR, 2.92 [1.62-5.26], P < .001) and DiGeorge syndrome (HR, 2.01 [1.15-3.51], P = .01) were independent and clinically important risk factors for reintervention.

CONCLUSIONS

For the repair of CAT, the LAA technique for right ventricle outflow tract reconstruction was associated with comparable survival and greater freedom from reintervention than the use of a valved conduit.

Cost-effectiveness of Artificial Intelligence for Proximal Caries Detection

Artificial intelligence (AI) can assist dentists in image assessment, for example, caries detection. The wider health and cost impact of employing AI for dental diagnostics has not yet been evaluated. We compared the cost-effectiveness of proximal caries detection on bitewing radiographs with versus without AI. U-Net, a fully convolutional neural network, had been trained, validated, and tested on 3,293, 252, and 141 bitewing radiographs, respectively, on which 4 experienced dentists had marked carious lesions (reference test). Lesions were stratified for initial lesions (E1/E2/D1, presumed noncavitated, receiving caries infiltration if detected) and advanced lesions (D2/D3, presumed cavitated, receiving restorative care if detected). A Markov model was used to simulate the consequences of true- and false-positive and true- and false-negative detections, as well as the subsequent decisions over the lifetime of patients. A German mixed-payers perspective was adopted. Our health outcome was tooth retention years. Costs were measured in 2020 euro. Monte-Carlo microsimulations and univariate and probabilistic sensitivity analyses were conducted. The incremental cost-effectiveness ratio (ICER) and the cost-effectiveness acceptability at different willingness-to-pay thresholds were quantified. AI showed an accuracy of 0.80; dentists’ mean accuracy was significantly lower at 0.71 (minimum–maximum: 0.61–0.78, P < 0.05). AI was significantly more sensitive than dentists (0.75 vs. 0.36 [0.19–0.65]; P = 0.006), while its specificity was not significantly lower (0.83 vs. 0.91 [0.69–0.98]; P > 0.05). In the base-case scenario, AI was more effective (tooth retention for a mean 64 [2.5%–97.5%: 61–65] y) and less costly (298 [244–367] euro) than assessment without AI (62 [59–64] y; 322 [257–394] euro). The ICER was −13.9 euro/y (i.e., AI saved money at higher effectiveness). In the majority (>77%) of all cases, AI was less costly and more effective. Applying AI for caries detection is likely to be cost-effective, mainly as fewer lesions remain undetected. Notably, this cost-effectiveness requires dentists to manage detected early lesions nonrestoratively.

Double orifice and atrioventricular septal defect: dealing with the zone of apposition†

OBJECTIVES

A double orifice of the left atrioventricular valve (LAVV) associated with atrioventricular septal defects (AVSD) can significantly complicate surgical repair. This study reports our experience of AVSD repair over 3 decades, with special attention to the zone of apposition (ZoA) of the main orifice, and presents a technique of hemivalve pericardial extension in specific situations.

METHODS

We performed a retrospective study from 1987 to 2016 on 1067 patients with AVSD of whom 43 (4%) had a double orifice, plus 2 additional patients who required LAVV pericardial enlargement. Median age at repair was 1.3 years. Mean follow-up was 8.2 years (1 month-32 years).

RESULTS

Associated abnormalities of the LAVV subvalvular apparatus were found in 7 patients (5 parachute LAVV and 2 absence of LAVV subvalvular apparatus). ZoA was noted in 4 patients (9%): partially closed in 15 (35%) and completely closed in 24 (56%). Four patients required, either at first repair or secondarily, a hemivalve enlargement using a pericardial patch without closure of the ZoA. The early mortality rate was 7% (n = 3), all before 2000. Two patients had unbalanced ventricles and the third had a single papillary muscle. There were no late deaths. Six patients (14%) required 7 reoperations (3 early and 4 late reoperations) for LAVV regurgitation and/or dysfunction, of whom 4 (9%) required mechanical LAVV replacement (all before 2000). Freedom from late LAVV reoperation was 97% at 1 year, 94% at 5 years and 87% at 10, 20 and 30 years. Unbalanced ventricles (P = 0.045), subvalvular abnormalities (P = 0.0037) and grade >2 LAVV postoperative regurgitation (P = 0.017) were identified as risk factors for LAVV reoperations. Freedom from LAVV mechanical valve replacement was 95% at 1 year, 90% at 5 years and 85% at 10, 20 and 30 years. An anomalous LAVV subvalvular apparatus was identified as a risk factor for mechanical valve replacement (P = 0.010). None of the patients who underwent LAVV pericardial extension had significant LAVV regurgitation at the last follow-up examination.

CONCLUSIONS

Repair of AVSD and double orifice can be tricky. Preoperative LAVV regurgitation was not identified as an independent predictor of surgical outcome. LAVV hemivalve extension appears to be a useful and effective alternate surgical strategy when the ZoA cannot be closed.

Mapping Cell Membrane Organization and Dynamics Using Soft Nanoimprint Lithography

Membrane shape is a key feature of many cellular processes, including cell differentiation, division, migration, and trafficking. The development of nanostructured surfaces allowing for the in situ manipulation of membranes in living cells is crucial to understand these processes, but this requires complicated and limited-access technologies. Here, we investigate the self-organization of cellular membranes by using a customizable and benchtop method allowing one to engineer 1D SiO₂ nanopillar arrays of defined sizes and shapes on high-performance glass compatible with advanced microscopies. As a result of this original combination, we provide a mapping of the morphology-induced modulation of the cell membrane mechanics, dynamics and steady-state organization of key protein complexes implicated in cellular trafficking and signal transduction.

Risk factors of mortality and recoarctation after coarctation repair in infancy

OBJECTIVES

The main challenge of aortic coarctation (CoA) repair in infants is to obtain durable results without morbidity. We aimed to describe predictors of aortic arch reintervention after aortic CoA repair.

METHODS

Between January 2000 and March 2014, we retrospectively included consecutive infants with isolated CoA or CoA with ventricular septal defect (CoA + VSD) who had surgical repair of the aortic arch before 3 months of age.

RESULTS

Five hundred and thirty patients were included: 308 (58%) patients had isolated CoA and 222 (42%) patients had CoA + VSD. Three hundred and eighty-five patients (72.6%) had CoA repair, 51 patients (9.6%) had CoA repair with closure of VSD and 94 patients (17.8%) had CoA repair with pulmonary artery banding. Mean age at operation was 13 ± 1.6 days, with 294 patients (55.5%) operated on before 2 weeks. Median follow-up was 7.57 years. Sixty-one patients (11.5%) needed reintervention on the aortic arch. Freedom from aortic arch reintervention was 90% at 1 year and 88.5% at 5 years. Proportions of aortic arch reintervention were similar in the different surgical strategy groups (P = 0.80). However, in patients receiving prostaglandin E1 (PGE1), the end-to-end repair was at higher risk of recoarctation compared to the extended end-to-side repair (P = 0.033). The risk factors of aortic arch reintervention were age at repair <15 days (P = 0.034) and the need for PGE1 infusion at surgery (P = 0.0043).

CONCLUSIONS

CoA repair in young infants has an overall good outcome. The use of PGE1 may modify the aortic arch anatomy and mask the boundaries of the resection to be performed. PGE1 treatment should be studied more specifically in another study to improve preoperative management.

Ascending aorta and aortic root replacement (with or without valve sparing) in early childhood: surgical strategies and long-term outcomes

OBJECTIVES

Aortic root and ascending aorta replacements (AARs) are rarely required in the paediatric population. We report here a series of AAR performed in young children using different surgical techniques.

METHODS

Between 1995 and 2017, 32 children under the age of 10 years (median age 5.4 years) underwent AAR procedures at our institution. Twenty-two (69%) had a connective tissue disease (infantile Marfan syndrome or Loeys-Dietz syndrome). We performed 11 AAR using a composite graft with a mechanical prosthesis and 21 valve-sparing procedures (10 Yacoub operations and 11 David operations). Median follow-up for operative survivors was 7.7 years (interquartile range 4.2-12.8 years).

RESULTS

The cardiac-related early mortality rate was 6%. Patient survival was 91% at both 1 and 10 years. Eleven survivors (38%), all with a status of post-valve-sparing procedure, required an aortic root reintervention with an aortic valve replacement after a median interval of 4.2 years. Interestingly, only patients with infantile Marfan syndrome tended to be associated with risk of reoperation.

CONCLUSIONS

Aortic root and AARs are safe in young children whatever the surgical procedure. Aortic valve-sparing procedures show good long-term results except in children with infantile Marfan syndrome whose ineluctable aortic annulus dilatation or aortic valve regurgitation requires reintervention after a short period.

Outcomes of palliative right ventricle to pulmonary artery connection for pulmonary atresia with ventricular septal defect

OBJECTIVES

To determine the early, intermediate and long-term outcomes of pulmonary atresia with ventricular septal defect (PA/VSD) Types I, II and III initially palliated by a right ventricle to pulmonary artery (RVPA) connection.

METHODS

We performed a retrospective study from 2000 to 2014 that included 109 patients with PA/VSD who had undergone an RVPA connection (tetralogy of Fallot and PA/VSD Type IV excluded). The end-points of this strategy were adequate pulmonary artery tree post-palliation, second palliation, biventricular repair, right ventricular pressure post-biventricular repair and late reoperation. Mean follow-up was 5.4 years (1 day to 14-78 years).

RESULTS

Early mortality after an RVPA connection was 2.7% (3 of 109). The interstage mortality rate was 6.6% (7 of 106). Eighty-four (77%) patients had a biventricular repair and 8 patients (7%) are awaiting repair. Overall survival was 90% at 1 year and 81% at 10 years. The RVPA connection allowed significant growth of the native pulmonary artery with a Nakata index of 101 mm2/m2 before the RVPA connection and 274 mm2/m2 after (P = 0.001). Twenty-nine reinterventions for restrictive pulmonary blood flow have been done (9 before 2 months and 20 after 2 months). Of the 84 patients who had a repair, 22 patients (26%) initially had a right ventricular pressure greater than 40 mmHg. Twenty-eight patients (33%) required late reoperation.

CONCLUSIONS

Hospital deaths after the RVPA connection were low. The procedure allowed good growth of the native pulmonary artery. Biventricular repair was possible in a large number of cases. The late morbidity rate remains significant. Early reinterventions could be avoided by appropriate calibration. This technique appears to be suitable for any type of PA/VSD with central pulmonary arteries.

Anomalous aortic origin of coronary arteries: 'anatomical' surgical repair

Anomalous aortic origin of coronary arteries (left coronary from right sinus or right coronary from left sinus) is a rare congenital defect, which carries a high risk of sudden cardiac death. The risk is particularly high when the interarterial course between the great arteries has an intramural segment, or is hypoplastic/stenotic, or has an abnormal orifice. Various surgical techniques have been used, including coronary artery bypass grafting, pulmonary artery translocation, partial or complete unroofing of the intramural course and patch enlargement of the interarterial course. We favour 'anatomical' repair that creates an enlarged neo-ostium into the appropriate sinus, eliminates completely the intramural segment and restores a normal angle of take-off. Reimplantation of the anomalous coronary artery may be indicated in variants without an intramural course. Surgical correction is mandatory for symptomatic and asymptomatic patients with evidence of myocardial ischaemia under stress; it is recommended in asymptomatic patients with high-risk variants (anomalous left coronary artery with the intramural course), particularly in young patients with strenuous activities.

Biological monitoring of exposure to di(2-ethylhexyl) phthalate in six French factories: a field study

OBJECTIVE

The aim of this study was to assess, by biological monitoring, workers' exposure to di(2-ethylhexyl) phthalate (DEHP) in the flexible-PVC industry in France to provide additional occupational exposure data, which are particularly scarce.

METHOD

Over 5 days of pre-and post-shift sampling, three urinary metabolites of DEHP, mono (2-ethylhexyl) phthalate (MEHP), mono (5-carboxy-2-ethylpentyl) phthalate (5cx-MEPP) and 2-ethylhexanoic acid (2-EHA) were quantified in 62 workers and 29 controls from six factories. Analyses were performed by high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS) after on-line extraction.

RESULTS

Median concentrations of the pre- and post-shift urinary samples in the exposed workers were 12.6 and 28.7 μg/l for MEHP, 38.6 and 84.4 μg/l for 5cx-MEPP and 20.4 and 70.6 μg/l for 2-EHA, respectively. In the controls, the corresponding values were 4.8 and 4.7 μg/l for MEHP, 15.1 and 12.4 μg/l for 5cx-MEPP and 21.8 and 20.5 μg/l for 2-EHA, respectively. There was a significant increase (Mann-Whitney U-test, P < 0.05) of post-shift excretion in the exposed workers versus the unexposed controls and in the post-shift versus pre-shift concentrations only in the exposed workers. Values of 250 and 500 μg/l (100 and 280 μ/g creatinine) for MEHP and 5cx-MEPP, respectively, are proposed as guidance values.

CONCLUSION

There is clear evidence of occupational exposure of workers in these factories. The guideline values proposed should prevent high exposures in the soft PVC industry, particularly in factories where DEHP compounds or plastisols are employed. An epidemiological survey is needed to complete the DEHP risk assessment.

Quantitative assessment of homograft function 1 year after insertion into the pulmonary position: impact of in situ homograft geometry on valve competence

AIMS

To prospectively evaluate homograft function with cardiac magnetic resonance (CMR) imaging 1 year after insertion into the pulmonary position, and to assess the impact of in situ homograft geometry, surgical factors, and 'intrinsic' homograft properties on early valve incompetence.

METHODS AND RESULTS

A total of 60 patients (mean age 21 +/- 10 years; 35 females) with congenital heart disease underwent pulmonary valve replacement with homograft insertion and were prospectively enrolled into a study protocol that included serial echocardiography and CMR 1 year after surgery. None of the patients had homograft stenosis but 10 (17%) had significant homograft incompetence (i.e. pulmonary regurgitation fraction >20% on CMR). A higher incidence of 'eccentric' pulmonary forward flow pattern (P < 0.001, Fisher's exact test), more acute 'homograft distortion angle' (P < 0.001), larger relative 'annular' size (P < 0.01), and greater pre-homograft right ventricular outflow tract (RVOT) diameters (P = 0.01) at CMR was seen in those with worse homograft function. In a backward multivariate linear regression model, 'eccentric' pulmonary forward flow pattern (r(part) = 0.36, P < 0.001), 'homograft distortion angle' (r(part) = 0.31, P = 0.001), and pre-homograft RVOT diameter (r(part) = 0.19, P = 0.03) were independently associated with the degree of pulmonary regurgitation (in %) at 1 year.

CONCLUSION

Using CMR, in this prospective cohort study, we have shown that significant valve incompetence is present in one-sixth of patients after homograft insertion into the pulmonary position, and that alterations in the in situ homograft geometry were associated with the likelihood of developing valve incompetence. These findings imply that mechanical factors may have an important impact on homograft performance.

N -Nitrosodiethanolamine urinary excretion in workers exposed to aqueous metalworking fluids

OBJECTIVE

This work was intended to clarify the extent of exposure of workers occupationally exposed to N-nitrosodiethanolamine (NDELA), a carcinogenic nitrosamine, while working with aqueous metalworking fluids (MWFs) formulated with ("nitrite-formulated") or without ("nitrite-free") nitrite and to study the relationships between the nitrite and NDELA content of the MWFs as well as between the concentration of NDELA in MWFs and in urine.

METHOD

Pre-shift and post-shift urine samples from 100 workers directly exposed to MWFs in 15 factories were analysed for NDELA with chemiluminescent detection (TEA) according to a previously described analytical procedure. The method was also applied to eight indirectly exposed workers and to 48 unexposed subjects. The NDELA and concentrations in 84 fluids used by the workers were also determined.

RESULTS

No detectable NDELA could be observed in the control group. The mean post-shift NDELA excretion in workers exposed to "nitrite-formulated" and "nitrite-free" MWFs were 44.6 and 0.4 microg/l, with maxima of 277 and 2.7 microg/l, respectively. According to the correlation between the nitrite and NDELA concentrations in "nitrite-free" MWFs, there is a low probability of fluids exceeding 5 mg/l NDELA when the nitrite content does not exceed 20 mg/l. The NDELA concentrations in the fluids and urine were found to be highly correlated, particularly after correction for creatinine (r=0.917 in post-shift samples). Cutaneous contact probably contributes, at least in part, to the overall body uptake of NDELA:

CONCLUSION

Due to clear evidence of urinary NDELA excretion in workers exposed to contaminated MWFs, and despite a lack of knowledge of the human risk following NDELA exposure, levels of NDELA in MWFs should be kept as low as possible. NDELA fluid concentrations of less than 1 mg/l must be considered as the objective to be attained, even if the limit of 5 mg/l is temporarily satisfactory and consistent with a nitrite limit of 20 mg/l that is easy to verify with inexpensive colorimetric tests. "Nitrite-formulated" fluids, still sometimes used, should be prohibited. Meanwhile, the material safety data sheets (MSDS) of commercially available products should be clearly labelled to indicate their nitrite content.

Determination of N-nitrosodiethanolamine in urine by gas chromatography thermal energy analysis: application in workers exposed to aqueous metalworking fluids

OBJECTIVE

The aim of this study was to describe a detailed and validated methodology designed for the analysis of carcinogenic N-nitrosodiethanolamine (NDELA) down to sub-microgram/l levels in urine and its application to a number of workers exposed to NDELA-contaminated aqueous metalworking fluids (MWF).

METHODS

Following a work-up procedure based on solid-phase extraction of NDELA, the urinary extracts were analysed without derivatization by gas chromatography on a polar wide-bore column with chemiluminescent detection using a thermal energy analyser (TEA). N-Nitroso-(2-hydroxypropyl)amine was used as an internal standard. The method was applied to 12 workers using "nitrite-free" or "nitrite-formulated" MWF and to 15 unexposed subjects. The NDELA content of the MWF was also determined using a similar, but simpler method able to easily quantify NDELA down to at least 0.1 mg/l.

RESULTS

Contamination by NDELA traces of some chemicals used for the sample preparation, particularly ethyl formate, must be carefully checked since it can give rise to false-positive results of up to 1 or 2 micrograms/l. The response was linear in the range of 0-500 micrograms/l. Between 0.5 and 10 micrograms/l, the recovery rate was close to 95%, while repeatability ranged from 12.5 to 6.4% (n = 5). The detection limit was 0.3 microgram/l (Signal/noise = 3). No detectable NDELA could be observed in the control workers. There was no significant increase in NDELA levels at the end of shift spot samples from an exposed worker over 1 week. Higher NDELA concentrations were found in two workers (4.3 and 10.7 micrograms/l) exposed to "nitrite-formulated" fluids (contaminated with 65 and 18 mg NDELA per 1, respectively) than in nine workers (range, 0.4-1.3 micrograms/l exposed to "nitrite-free" fluids with lower levels of NDELA (range, 0.5-6.6 mg/l).

CONCLUSION

The detailed methodology described in this work and applied to a limited industrial situation was found to be suitable for monitoring NDELA in the urine of workers exposed to aqueous MWF. A much larger screening has been undertaken with the aim of obtaining better information on the real exposure of workers sometimes exposed to "nitrite-formulated" fluids that are still used.

trans,trans-Muconic acid, a reliable biological indicator for the detection of individual benzene exposure down to the ppm level

trans,trans-Muconic acid (2,4-hexadienedioic acid) (t,t-MA) is a minor benzene metabolite which can be used as a biological indicator for benzene exposure. The purpose of the study was to evaluate the limits of use of t,t-MA for detection and quantification of occupational exposures to benzene, particularly on an individual scale, phenol being used as the metabolite of reference. A simple and sensitive method previously described by the authors was carried out to analyse t,t-MA in 105 end-of-shift urinary samples from 23 workers exposed to benzene used as an extraction solvent for "concretes" recovery in the perfume industry. Good correlations were found between atmospheric benzene and both metabolites (uncorrected or corrected for creatinine) or between the metabolites themselves, with correlation coefficients from 0.81 to 0.91 (P < 0.0001). Correlation- coefficients were not improved after correction for creatinine. The overall individual benzene exposure range, median, and arithmetic mean were respectively 0.1-75, 4.5, and 9.0 ppm with corresponding t,t-MA excretion of 0.1-47.9, 5.2 and 8.9 mg/l (uncorrected) and phenol excretion of 1.4-298, 30.9, and 42.2 mg/l (uncorrected). In the control group (145 determinations for t,t-MA and 76 for phenol from 79 individuals) the range, median, and arithmetic mean were respectively < 0.04-0.66, 0.08, and 0.13 mg/l (uncorrected t,t-MA) and 1.5-42.0, 9.85 and 11.3 mg/l (uncorrected phenol). t,t-MA was far more specific than phenol and could be easily and practically used to estimate with a given probability the upper or lower corresponding benzene concentrations down to around the ppm level.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of the interaction of benzene and toluene on the urinary excretion of t,t-muconic acid in rats

The influence of simultaneous exposure to benzene and toluene on the urine excretion of t,t-muconic acid (t,t-MA) was examined in rats. t,t-MA was measured from 24-h urine of rats subjected to a single 4-h exposure to 5 or 20 ppm benzene and/or 50, 100, 200 or 1000 ppm toluene. Coexposure lowered t,t-MA excretion in a concentration-dependent manner, especially in the 20 ppm benzene group where the decrease averaged 28, 44 and 85% after exposure to 100, 200 and 1000 ppm toluene, respectively, as compared to benzene-exposed groups alone. The data confirm the sensitivity of t,t-MA as an indicator of benzene exposure and point out that measurement of t,t-MA may underestimate the exposure to benzene in the presence of toluene.

Improvement in HPLC analysis of urinary trans,trans-muconic acid, a promising substitute for phenol in the assessment of benzene exposure

Urinary trans,trans-muconic acid (t,t-MA), a minor metabolite of benzene, is a potential candidate for biological monitoring of benzene. A clean-up procedure using SPE extraction cartridges was applied to urinary samples in order to improve the reliability of t,t-MA determinations by HPLC-UV greatly and to carry out convenient analyses on a routine scale, particularly at low levels of t,t-MA concentrations. The detection limit of the method is low enough to measure urinary t,t-MA at a concentration of 0.05-0.1 mg/l. The recovery rates and relative standard deviations from spiked urines (1 mg/l to 20 mg/l) were about 90% and 5%, respectively. t,t-MA was found to be rapidly excreted by rats and humans. In rats the background range never exceeded 0.5 mg/l with a mean concentration around 0.3 mg/l. In 49 human blank urines, t,t-MA average and median-value were respectively around 0.2 and less than 0.1 mg/l with a range of less than 0.1 to 0.5 mg/l. Experimental exposure of rats for 1 h to 10.2 ppm of benzene induced urinary excretion of 13 mg/l of t,t-MA during a 6-h post-exposure period while occupational exposures to 2.6 ppm (mean exposure level during 5 d-8 h) and 7 ppm (4 h) of benzene resulted in urinary excretion of 2.1 (mean excretion level) and 6.5 mg/l respectively at the end of the exposure. In humans, t,t-MA has a similar half-time as phenol. Analysis of urinary t,t-MA seems to be a better indicator than phenol for the assessment of exposure to low levels of benzene. Ingestion of 200 mg of sorbic acid, the only other known precursor of t,t-MA, interfered minimally with the background excretion of t,t-MA.

Guinea pig pulmonary response to sensitization by five preformed monoisocyanate-ovalbumin conjugates

The ability of 5 dissimilar monoisocyanates conjugated to ovalbumin (OA) as a carrier protein to induce pulmonary hypersensitivity towards the hapten specific component was assessed by using a previously described method based on the determination of a respiratory index (RI) in the guinea pig. The test chemicals included the commercially available p-tolyl and hexyl monoisocyanates (TMI and HMI), with 4-isocyanoto-4'-diphenylmethane (IDM), 4-isocyanoato-4'-methyldiphenylmethane (IMDM) and 1-isocyanato-methyl-1,3,3-trimethylcyclohexane (IMTC) as synthetized monoisocyanates. Guinea pigs were exposed daily to an aerosol of the OA conjugate of each monoisocyanate up to day 15. Increases in respiratory rate and/or respiratory collapse occurred in the guinea pigs exposed to TMI-OA and HMI-OA conjugates by days 9 and 15, with RI values of 155 and 177, respectively, being recorded. The greatest mean RI values in guinea pigs exposed to IDM-OA, IMDM-OA and IMTC-OA conjugates up to day 15 were 20, 25 and 22, respectively, and were not indicative of any pulmonary reaction. Guinea pigs exposed in parallel to each test conjugate did not exhibit any pulmonary reaction when they were exposed to OA on the challenge days. All these findings evidence pulmonary hypersensitivity as the result of exposure to TMI-OA and HMI-OA conjugates and suggest a high degree of conjugation and strong linkage of all the monoisocyanates with OA.(ABSTRACT TRUNCATED AT 250 WORDS)

Assessment of occupational exposure to 4,4'-methylene-bis-(2-chloroaniline) "MOCA" by a new sensitive method for biological monitoring

A new specific and sensitive method for the urinary determination of 4,4'-methylene-bis-(2-chloroaniline) ("MOCA"), a known carcinogen in rats, mice and dogs, has been developed. After a brief study on rats to determine some peculiarities in "MOCA" urinary excretion, this method was used to assess occupational exposure in French industrial firms. Both the manufacture of "MOCA" and its use as a curing agent in the production of polyurethane elastomers were surveyed. "MOCA" excretion levels were distributed from non-detectable (less than 0.5 microgram/l) up to 1600 microgram/l. Concentrations of N-acetyl metabolites, when present, were largely lower than "MOCA" levels. The results seemed to reflect workers' overall exposure fairly. Preventive measures following analytical determinations often led to an obvious lowering of excretion levels.

N-nitrosodiethanolamine in antifreeze

Carcinogenic N-nitrosodiethanolamine has been found at concentrations varying from 15 to 5700 mg/liter in several leading French brands of antifreeze. Moreover, mixtures of antifreezes which, separately, are innocuous, can form this nitrosamine which appears to arise from interaction of triethanolamine derivatives with sodium nitrite. It is recommended that sodium nitrite be abandoned as an anticorrosion additive.