Molecular basis for ATPase-powered substrate translocation by the Lon AAA+ protease.

The Lon AAA+ (adenosine triphosphatases associated with diverse cellular activities) protease (LonA) converts ATP-fuelled conformational changes into sufficient mechanical force to drive translocation of a substrate into a hexameric proteolytic chamber. To understand the structural basis for the substrate translocation process, we determined the cryo-electron microscopy (cryo-EM) structure of Meiothermus taiwanensis LonA (MtaLonA) in a substrate-engaged state at 3.6 Å resolution. Our data indicate that substrate interactions are mediated by the dual pore loops of the ATPase domains, organized in spiral staircase arrangement from four consecutive protomers in different ATP-binding and hydrolysis states. However, a closed AAA+ ring is maintained by two disengaged ADP-bound protomers transiting between the lowest and highest position. This structure reveals a processive rotary translocation mechanism mediated by LonA-specific nucleotide-dependent allosteric coordination among the ATPase domains, which is induced by substrate binding.

Outcome of Tricuspid Valve Plasty in Norwood Stage I Operation.

BACKGROUND: Significant tricuspid valve regurgitation (TR) is considered a poor prognosis factor for patients with hypoplastic left heart syndrome (HLHS). Performing a tricuspid valve plasty (TVP) during Norwood Stage I palliation (S1P) has rarely been reported. We report mid-term results of performing TVP during Norwood S1P. METHODS AND RESULTS: Between December 2004 and July 2013, 48 patients with HLHS or variants underwent Norwood S1P and of them 11 (23%) with TR of a moderate degree or above underwent TVP. The estimated 1- and 5-year survival rates for Norwood S1P were 61% and 54%, respectively. Among the 11 patients with TVP, there were 2 early deaths. Nine patients had a Stage II operation and 3 of them died late. Four patients completed a Fontan operation, and 2 were waiting. Using Cox regression analysis, lower body weight, presence of intact atrial septum, and preoperative cardiopulmonary resuscitation were factors associated with increased risk for death. Patients with significant TR and undergoing TVP during Norwood S1P had a similar survival curve to those without significant TR. CONCLUSIONS: Our results for TVP performed during Norwood S1P were encouraging. They suggested that aggressive TVP is warranted in Norwood S1P when primary heart transplantation is not available. Further study is required to determine if the strategy does improve the results for patients with HLHS and TR initially. (Circ J 2016; 80: 1362-1370).

The Concept of the Arch Window in the Spiral Switch of the Great Arteries.

When the arterial switch operation includes the Lecompte maneuver, the arterial trunks are reconnected in parallel, rather than the spiral fashion observed in the normal heart. Thus, although the ventriculo-arterial connections are hemodynamically corrected, the anatomic arrangement cannot be considered normal. We hypothesized that, if feasible, it would be advantageous to restore a spiral configuration for the arterial trunks. In 58 patients, we reconstructed the arterial trunks such that, postoperatively, the pulmonary channel spirals round the aorta, passing to either the right or the left, and branches posteriorly. We compared the outcomes with those in 95 patients undergoing a standard non-spiraling operation over the same period. Average follow-up was 8.2 ± 4.5 years. The estimated 10-year survival was similar in the cohorts, at 94.7 % for those with spiraling trunks, as compared to 90.4 % for those with parallel outflow tracts. Reoperation-free survival at 10 years was not significantly different (87.6 vs. 90.5 %). Supravalvar pulmonary stenosis, aortic neo-coarctation, or left bronchial stenosis, however, was encountered in one-eighth of those undergoing a standard operation. None of these complications occurred in those patients who, postoperatively, had spiraling outflow tracts (P = 0.002). Reconstruction of spiraling trunks after the arterial switch has, thus far, avoided the complications of supravalvar pulmonary stenosis, neo-aortic kinking, or bronchial stenosis. The spiraling arrangement prevents compression of the pulmonary vessels and bronchial tree by the aorta, since it provides a wide window in the new aortic arch.

Endocytotic routes of cobra cardiotoxins depend on spatial distribution of positively charged and hydrophobic domains to target distinct types of sulfated glycoconjugates on cell surface.

Cobra cardiotoxins (CTX) are a family of three-fingered basic polypeptides known to interact with diverse targets such as heparan sulfates, sulfatides, and integrins on cell surfaces. After CTX bind to the membrane surface, they are internalized to intracellular space and exert their cytotoxicity via an unknown mechanism. By the combined in vitro kinetic binding, three-dimensional x-ray structure determination, and cell biology studies on the naturally abundant CTX homologues from the Taiwanese cobra, we showed that slight variations on the spatial distribution of positively charged or hydrophobic domains among CTX A2, A3, and A4 could lead to significant changes in their endocytotic pathways and action mechanisms via distinct sulfated glycoconjugate-mediated processes. The intracellular locations of these structurally similar CTX after internalization are shown to vary between the mitochondria and lysosomes via either dynamin2-dependent or -independent processes with distinct membrane cholesterol sensitivity. Evidence is presented to suggest that the shifting between the sulfated glycoconjugates as distinct targets of CTX A2, A3, and A4 might play roles in the co-evolutionary arms race between venomous snake toxins to cope with different membrane repair mechanisms at the cellular levels. The sensitivity of endocytotic routes to the spatial distribution of positively charged or hydrophobic domains may provide an explanation for the diverse endocytosis pathways of other cell-penetrating basic polypeptides.

Total Synthesis of Hispidulin and the Structural Basis for Its Inhibition of Proto-oncogene Kinase Pim-1.

A new method is applied to synthesize hispidulin, a natural flavone with a broad spectrum of biological activities. Hispidulin exhibits inhibitory activity against the oncogenic protein kinase Pim-1. Crystallographic analysis of Pim-1 bound to hispidulin reveals a binding mode distinct from that of quercetin, suggesting that the binding potency of flavonoids is determined by their hydrogen-bonding interactions with the hinge region of the kinase. Overall, this work may facilitate construction of a library of hispidulin-derived compounds for investigating the structure-activity relationship of flavone-based Pim-1 inhibitors.

Ventricular geometric characteristics and functional benefit of mild right ventricular outflow tract obstruction in patients with significant pulmonary regurgitation after repair of tetralogy of Fallot.

BACKGROUND: Right ventricular (RV) outflow tract obstruction (RVOTO) might protect the RV from adverse remodeling caused by significant pulmonary regurgitation (PR) in patients with repaired tetralogy of Fallot (rTOF), but the underlying mechanisms and influences on exercise tolerance remain unclear. This study sought to investigate the impacts from mild RVOTO on ventricular remodeling and exercise capacity in rTOF. METHODS: Eighty-five rTOF patients with a PR fraction ≥20% were assessed with cardiac magnetic resonance, cardiopulmonary exercise test, and echocardiography. Patients with a peak RVOT pressure gradient 20-50 mmHg were considered to have mild RVOTO (n = 29), while those with a gradient <20 mmHg had isolated PR (n = 56). RESULTS: Comparing to patients with isolated PR, patients with combined PR and mild RVOTO had smaller RV and RVOT dimension, better RV and left ventricular (LV) ejection fraction (EF), and superior exercise capacity. PR severity and RV mass/volume ratio were similar between these 2 groups. LVEF coupled with RVEF only in patients with isolated PR. In multivariate analysis, smaller RVOT dimension was independently related to smaller RV dimension (P < .001) and higher RVEF (P = .005). Furthermore, mild RVOTO was independently associated with higher peak oxygen consumption (P = .014) and oxygen uptake efficiency slope (P = .005). CONCLUSIONS: Patients with combined PR and mild RVOTO had better RV remodeling and exercise capacity compared to those with isolated PR. Our findings confirm the benefits from mild residual RVOTO support a policy of conservative RVOTO relief at repair.

Risk stratification and outcome of cardiac surgery for patients with body weight <2 ,500g in an Asian center.

BACKGROUND: Cardiac surgery performed in patients with low body weight is a challenge for surgeons. Currently, such outcomes are mainly reported from European or North American centers. In this study, we review our cardiac surgery experience with neonates and infants weighing <2,500g. METHODS AND RESULTS: We included patients with a body weight <2,500g who received cardiac surgery between January 2008 and December 2012. The survival outcome was compared to that of patients with large body weight, and then the Risk Adjusted Classification for Congenital Heart Surgery (RACHS-1) categorization was used for operative risk stratification. In the 1,245 index operations, 53 patients (4.3%) were <2,500g. The mean body weight was 2,232g (range 1,320-2,500g). The hospital mortality rate was 20.7% (11/53). Most (85%) of the procedures were in RACHS-1 category ≥3. The risk ratio was significantly higher in RACHS-1 category 3 (relative risk [RR]:6.2; 95% confidence interval [CI]:1.6-23.9) and 4 (RR:4.6; 95% CI:1.4-15.0), respectively, while it was not significantly different in category 2 (RR:1.02; 95% CI:1.01-1.02) and category 6 (RR:2.9; 95% CI:0.36-13.3). CONCLUSIONS: Cardiac surgery performed on infants with low body weight is generally a complex procedure, but the results are acceptable. The risk was higher than that for patients with higher body weight in RACHS-1 category 3 and 4. Further investigation to improve the outcome of this high-risk group is needed.

Clinical Applications of Extracorporeal Membranous Oxygenation: A Mini-Review.

UNLABELLED: The clinical usage of extracorporeal membranous oxygenation began more than 40 years ago. Although the indications for its use have expanded over the years, it has been challenging to conduct randomized controlled trials to prove that extracorporeal membranous oxygenation is more effective than traditional approaches. Through a review of retrospective reports and data from registries, we attempted to evaluate the appropriateness of its application for acute respiratory distress syndrome, cardiopulmonary resuscitation, postcardiotomy cardiogenic shock, and sepsis. Our investigation revealed that using extracorporeal membranous oxygenation when readily available is appropriate for all patients with cardiopulmonary resuscitation or postcardiotomy cardiogenic shock, and for selected patients with acute respiratory distress syndrome or sepsis. KEY WORDS: Acute respiratory distress syndrome; Cardiopulmonary resuscitation; Extracorporeal membranous oxygenation; Postcardiotomy cardiogenic shock; Sepsis.

Structural basis for recruitment of peptidoglycan endopeptidase MepS by lipoprotein NlpI.

Peptidoglycan (PG) sacculi surround the cytoplasmic membrane, maintaining cell integrity by withstanding internal turgor pressure. During cell growth, PG endopeptidases cleave the crosslinks of the fully closed sacculi, allowing for the incorporation of new glycan strands and expansion of the peptidoglycan mesh. Outer-membrane-anchored NlpI associates with hydrolases and synthases near PG synthesis complexes, facilitating spatially close PG hydrolysis. Here, we present the structure of adaptor NlpI in complex with the endopeptidase MepS, revealing atomic details of how NlpI recruits multiple MepS molecules and subsequently influences PG expansion. NlpI binding elicits a disorder-to-order transition in the intrinsically disordered N-terminal of MepS, concomitantly promoting the dimerization of monomeric MepS. This results in the alignment of two asymmetric MepS dimers respectively located on the two opposite sides of the dimerization interface of NlpI, thus enhancing MepS activity in PG hydrolysis. Notably, the protein level of MepS is primarily modulated by the tail-specific protease Prc, which is known to interact with NlpI. The structure of the Prc-NlpI-MepS complex demonstrates that NlpI brings together MepS and Prc, leading to the efficient MepS degradation by Prc. Collectively, our results provide structural insights into the NlpI-enabled avidity effect of cellular endopeptidases and NlpI-directed MepS degradation by Prc.

The N-terminal substrate-recognition domain of a LonC protease exhibits structural and functional similarity to cytosolic chaperones.

The Lon protease is ubiquitous in nature. Its proteolytic activity is associated with diverse cellular functions ranging from maintaining proteostasis under normal and stress conditions to regulating cell metabolism. Although Lon was originally identified as an ATP-dependent protease with fused AAA+ (ATPases associated with diverse cellular activities) and protease domains, analyses have recently identified LonC as a class of Lon-like proteases with no intrinsic ATPase activity. In contrast to the canonical ATP-dependent Lon present in eukaryotic organelles and prokaryotes, LonC contains an AAA-like domain that lacks the conserved ATPase motifs. Moreover, the LonC AAA-like domain is inserted with a large domain predicted to be largely α-helical; intriguingly, this unique Lon-insertion domain (LID) was disordered in the recently determined full-length crystal structure of Meiothermus taiwanensis LonC (MtaLonC). Here, the crystal structure of the N-terminal AAA-like α/ß subdomain of MtaLonC containing an intact LID, which forms a large α-helical hairpin protruding from the AAA-like domain, is reported. The structure of the LID is remarkably similar to the tentacle-like prong of the periplasmic chaperone Skp. It is shown that the LID of LonC is involved both in Skp-like chaperone activity and in recognition of unfolded protein substrates. The structure allows the construction of a complete model of LonC with six helical hairpin extensions defining a basket-like structure atop the AAA ring and encircling the entry portal to the barrel-like degradation chamber of Lon.

Structures of an ATP-independent Lon-like protease and its complexes with covalent inhibitors.

The Lon proteases are a unique family of chambered proteases with a built-in AAA+ (ATPases associated with diverse cellular activities) module. Here, crystal structures of a unique member of the Lon family with no intrinsic ATPase activity in the proteolytically active form are reported both alone and in complexes with three covalent inhibitors: two peptidomimetics and one derived from a natural product. This work reveals the unique architectural features of an ATP-independent Lon that selectively degrades unfolded protein substrates. Importantly, these results provide mechanistic insights into the recognition of inhibitors and polypeptide substrates within the conserved proteolytic chamber, which may aid the development of specific Lon-protease inhibitors.

Long-Term Outcomes of Native Coarctation of the Aorta after Balloon Angioplasty or Surgical Aortoplasty in Newborns and Young Infants Less Than 3 Months of Age.

BACKGROUND: Balloon angioplasty of native coarctation of the aorta, though effective, is frequently associated with early restenosis, repeated interventions and aneurysm formation, especially in very young patients. However, available long-term data are limited. METHODS: From Jan. 1986 to Dec. 2007, eighty-eight patients with simple aortic coarctation, isolated or associated with patent ductus arteriosus or ventricular septal defect, and survived angioplasty (n = 17) or surgery (n = 71) within 3 months of age in National Taiwan University Hospital were enrolled. RESULTS: The average length of follow-up was 10.1 ± 5.1 years. The long-term outcomes between these two groups were comparable in hypertension, left ventricular outflow tract obstruction, and aortic aneurysm. Patients in the angioplasty group had a greater likelihood of reintervention (64.7% vs. 42.3%, p = 0.096) and repeated reintervention (29.4% vs. 7.0%, p = 0.027) as compared with surgery group. The 10-year freedom from reintervention was 35.3% and 59.2% in the angioplasty and surgery group, respectively (p = 0.046); there were no deaths reported in that 10-year span. Patients with angioplasty and those with patent ductus arteriosus were more likely to require surgical aortoplasty at reintervention. CONCLUSIONS: The long-term outcomes of aortic coarctation in newborns and young infants after balloon angioplasty were effective and beneficial. However, those outcomes were accompanied by concomitant higher risks of reintervention and surgical reintervention, particularly in those with patent ductus arteriosus. KEY WORDS: Aortic operation; Coarctation; Infant; Outcomes.

Results and Complications After Single-Stage Repair of Aortopulmonary Window and Interrupted Aortic Arch in a 32-Week Preterm and a Full-Term Neonate.

BACKGROUND An aortopulmonary window (APW) is an uncommon congenital defect of the septation between the ascending aorta and pulmonary trunk. The combination of APW and interrupted aortic arch (IAA) is even rarer, with the hallmark characteristics of high peri-operative mortality and postoperative obstruction of the aortic arch, pulmonary artery, and left main bronchus. These complications often need re-interventions. CASE REPORT We present 2 cases with diagnoses of APW and IAA that were treated with single-stage repair. Case 1: A male 32-week premature newborn (weight 1789 g) had APW type I and IAA type A. He had severe postoperative aortic arch obstruction on postoperative day 1, and we re-intervened promptly. He was still asymptomatic after 6 years. Case 2: A male term neonate had APW type III and IAA type A. He had left vocal cord paralysis and left bronchial compression postoperatively. We applied prolonged noninvasive respiratory supports. The complications resolved without re-intervention on postoperative day 66. Progressive arch stenosis at anastomosis after operation required close follow-up with echocardiography. CONCLUSIONS These 2 reports highlight the feasibility of single-stage surgical repair while addressing 2 challenges: (1) Recurrent arch stenosis: Lower body weight and direct end-to-side anastomosis without patch augmentation could be risk factors for re-intervention. (2) Bronchial compression: Presentation of the second reported case implied that bronchial compression may not warrant immediate re-intervention unless there is complete obstruction, persistent atelectasis, or recurrent infection. Further studies on long-term outcomes of different surgical procedure would help us to clarify the proper way to avoid re-intervention.

Associated factors with parental pregnancy decision-making and use of consultation after a prenatal congenital heart disease diagnosis.

BACKGROUND: Prenatal diagnosis of congenital heart disease (CHD) often leads affected families to experience psychological stress. Pediatric cardiology consultation is important in providing parents with sufficient information and reducing their anxiety to make an informed pregnancy decision. Involving a fetal nurse coordinator may optimize fetal anomaly care. Our study aimed to identify factors associated with parental decision-making for choosing to use pediatric cardiology consultations and pregnancy termination. METHODS: From September 2017 to December 2018, all fetal CHD cases diagnosed in the second trimester from a primary screening clinic in Taiwan were included (n = 145). Univariate and multivariate logistic regression were performed to analyze maternal, fetal, and medical factors for predictors of parental decisions for consultation use and pregnancy termination. RESULTS: Acceptance for fetal nurse coordinator care and pediatric cardiology consultation were 84.8% (n = 123) and 83.4% (n = 121), respectively. Predictors for termination of pregnancy included the following: multiple anomalies (OR: 10.6; 95% CI: 3.6-35.7), chromosomal/genetic abnormalities (OR: 20.2; 95% CI: 3.1-395.8), severe CHDs (OR: 9.8; 95% CI: 4.3-23.4), CHDs that required surgery (OR: 32.4; 95% CI: 11.4-117.8), and physiological single-ventricle (OR: 47.3; 95% CI: 12.4-312.5). Parents who had pediatric cardiology counseling were less likely to terminate the pregnancy (OR: 0.1; 95% CI: 0.0-0.7). Parents with fetal diagnosis having multiple anomalies (OR: 0.2; 95% CI: 0.1-0.7) or chromosomal/genetic abnormalities (OR: 0.1; 95% CI: 0.03-0.9) were less likely to make use of cardiology consultation. Parents who accepted fetal nurse coordinator care were more likely to have pediatric cardiology consultation before pregnancy decision (OR: 149.5, 95% CI: 37.8-821.5). CONCLUSIONS: Anomaly complexity appeared to be a strong predictor for termination of pregnancy beyond non-acceptability of prenatal cardiology consultation. Prenatal cardiology counseling may help support the parental decision to continue with the pregnancy. Incorporation of a fetal nurse coordinator care into the multidisciplinary fetal medicine team improved the acceptability of prenatal consultation.

Clinical outcomes of handmade polytetrafluoroethylene trileaflet-valved conduit used for pulmonary valve replacement.

OBJECTIVES: To mitigate the shortage of homograft sources, the use of handmade trileaflet expanded polytetrafluoroethylene valves in pulmonary valve replacement has shown excellent results from multicentre studies conducted in Japan. However, world-wide data outside Japan are relatively insufficient. This study presents the long-term results of a single surgeon's use of flipped-back trileaflet method in a 10-year case series. METHODS: We have developed an efficient way to make a trileaflet-valved conduit utilizing flipped-back method for pulmonary valve replacement and have employed the technique since 2011. Retrospective data were studied between October 2010 and January 2020. Echocardiography, electrocardiogram, Pro-Brain Natriuretic Peptide and Magnetic Resonance Imaging data were analysed. RESULTS: Fifty-five patients were reviewed and median follow-up duration was 2.9 years. The majority of diagnoses was Tetralogy of Fallot (n = 41), and these patients subsequently underwent secondary pulmonary valve replacement at a median age of 15.6 years. Survival was 92.7% with the longest follow-up period being 10 years. There was no need for reoperation, and freedom from reintervention was 98.0% at 10 years. There were 4 deaths (3 in-hospital and 1 outpatient). One patient eventually received transcatheter pulmonary valve implantation. Postoperative echocardiography showed mild or less pulmonary stenosis and pulmonary regurgitation degree in 92.2% and 92.0% of patients, respectively. Comparable magnetic resonance imaging data (n = 25) showed significant reduction in right ventricular volumes but not in ejection fractions. CONCLUSIONS: Our series showed satisfactory long-term function of handmade flipped-back trileaflet-valved conduit used in our patients. The simple design is efficiently reproducible without complex fabrication process.

Structural basis for the hydrolytic activity of the transpeptidase-like protein DpaA to detach Braun's lipoprotein from peptidoglycan.

IMPORTANCE: Cross-linking reaction of Braun's lipoprotein (Lpp) to peptidoglycan (PG) is catalyzed by some members of the YkuD family of transpeptidases. However, the exact opposite reaction of cleaving the Lpp-PG cross-link is performed by DpaA, which is also a YkuD-like protein. In this work, we determined the crystal structure of DpaA to provide the molecular rationale for the ability of the transpeptidase-like protein to cleave, rather than form, the Lpp-PG linkage. Our findings also revealed the structural features that distinguish the different functional types of the YkuD family enzymes from one another.

A 5+1 assemble-to-activate mechanism of the Lon proteolytic machine.

Many AAA+ (ATPases associated with diverse cellular activities) proteins function as protein or DNA remodelers by threading the substrate through the central pore of their hexameric assemblies. In this ATP-dependent translocating state, the substrate is gripped by the pore loops of the ATPase domains arranged in a universal right-handed spiral staircase organization. However, the process by which a AAA+ protein is activated to adopt this substrate-pore-loop arrangement remains unknown. We show here, using cryo-electron microscopy (cryo-EM), that the activation process of the Lon AAA+ protease may involve a pentameric assembly and a substrate-dependent incorporation of the sixth protomer to form the substrate-pore-loop contacts seen in the translocating state. Based on the structural results, we design truncated monomeric mutants that inhibit Lon activity by binding to the native pentamer and demonstrated that expressing these monomeric mutants in Escherichia coli cells containing functional Lon elicits specific phenotypes associated with lon deficiency, including the inhibition of persister cell formation. These findings uncover a substrate-dependent assembly process for the activation of a AAA+ protein and demonstrate a targeted approach to selectively inhibit its function within cells.

Detection of pulmonary arterial morphology in tetralogy of Fallot with pulmonary atresia by computed tomography: 12 years of experience.

UNLABELLED: Our aim was to evaluate the feasibility of using computed tomography (CT) to define the pulmonary artery anatomy in patients with tetralogy of Fallot and pulmonary atresia (TOF-PA). We retrospectively reviewed 110 patients with TOF-PA between 1995 and 2008. Those who received cardiac catheterization and surgery within 3 months of their CT examinations were enrolled. Based on Dr. Somerville's classification, the pulmonary arterial pattern was determined, including identifiable pulmonary trunk (type I), the presence of both left and right pulmonary arteries without trunk (II), only left or right pulmonary artery present (III), and absent intrapericardial pulmonary arteries (IV). The accuracy of both imaging modalities was evaluated with operation findings as the golden standard. The effective radiation doses and adverse events were also recorded. In the 64 eligible patients (median age, 23 months), CT and catheterization demonstrated accurate pulmonary arterial morphology in 60 (60/64) and 53 (53/64) TOF-PA patients, respectively. Thirty-two of 35 type I patients were correctly identified by CT, whereas 26 were correctly identified by catheterization (p = 0.03). Of the 20 type II TOF-PA patients, 19 were diagnosed by CT, whereas 18 were diagnosed by catheterization. CT and catheterization both successfully defined six type III and three type IV patients. The median calculated radiation doses caused by CT and catheterization were 4.5 and 5.6 mSv, respectively (p > 0.05). CONCLUSIONS: For patients with TOF-PA, CT could accurately delineate pulmonary arterial morphology with the same level of accuracy as cardiac catheterization. Therefore, CT can be considered a reasonable diagnostic alternative for such patients.

Successful deployment of an iliac limb graft to repair acute aortic rupture after balloon aortoplasty of recoarctation in a child with Turner syndrome.

Aortic rupture is a rare but potentially catastrophic complication following a balloon aortoplasty for recoarctation. The treatment of aortic ruptures remains challenging. We present here a 9-year-old girl with Turner syndrome who experienced a life-threatening rupture in her aorta after a balloon aortoplasty for recoarctation. She was successfully rescued by the antegrade deployment of a commercially available iliac limb extension stent-graft via an ascending aortic conduit. Prudent balloon aortoplasty for recoarctation in patients with Turner syndrome is important due to their inherent aortopathy and previous surgical repairs. Possible reasons for an aortic rupture are oversized ballooning and the choice of balloon diameter based only on an angiographic measurement. In agreement with earlier reports, our case also confirms the importance of keeping a commercially available stent graft available to treat this complication that has potentially fatal consequences.

Natural and unnatural history of tetralogy of Fallot repaired during adolescence and adulthood.

Surgical repair of tetralogy of Fallot (TOF) in countries with sound medical care systems is seldom delayed until adolescence. This study investigated the clinical profile and the surgical outcomes in such a population from Taiwan. Between 1970 and 2009, 179 TOF patients (56% male) received total repair at 19.2 ± 8.3 (10-49) years of age. We reviewed the medical records and interviewed the patients concerning their current status. The survival was ascertained in all by a link to our national health database. Major morbidities before cardiac repair included atrial arrhythmia (1.1%), ventricular arrhythmia (3.9%), infective endocarditis (6.7%), brain abscess (4.6%) and pulmonary tuberculosis (3.3%). Ventricular arrhythmia and pulmonary tuberculosis occurred mainly after 20 years of age. Thirty patients (16.8%) received a palliative shunt. The preoperative QRS duration increment was 0.6 ms/year. Early mortality occurred in 4 (2.2%) and was related to previous shunt surgery (OR = 16.5, p < 0.05) and coronary artery crossing RVOT (OR 17.6, p < 0.05). After repair, the functional class improved in all patients. The median age at latest follow-up was 31.8 (32.8 ± 12.3) years. The survival was 92.7 and 89.3% at 20 and 30 years after operation, respectively. Late cardiovascular death could be predicted by the length of postoperative intensive care unit stay (OR = 1.3, p < 0.001). The freedom from ventricular arrhythmia 30 years after repair was 84.1% and was associated with a final QRS longer than 160 ms. Unrepaired TOF patients were at high risk of infective endocarditis, brain abscess, pulmonary tuberculosis and arrhythmias during their adolescence and adulthood. Cardiac repair in this age group was still safe and effective.