A sword threatening the heart: The scimitar syndrome

Abstract

Central MessageThis review deals with the natural and surgical history of patients with scimitar syndrome, describing the clinical presentation and possible results based on the choice of treatment.See Commentary on page 81. This review deals with the natural and surgical history of patients with scimitar syndrome, describing the clinical presentation and possible results based on the choice of treatment. See Commentary on page 81. Scimitar syndrome (SS) is a rare congenital heart anomaly consisting of anomalous venous drainage of part or the entire right lung into the upper portion of the inferior vena cava (IVC), right lung hypoplasia, and a variable systemic arterial blood supply to the right lung.1Vida V.L. The Complete Reference for Scimitar Syndrome. Academic Press, London2017Google Scholar,2Opotowsky A.R. Webb G.D. A battle in the crusade to understand scimitar syndrome.Eur Heart J. 2018; 39: 1012-1014Crossref PubMed Scopus (5) Google Scholar This malformation has been described by many pathologists over time. In an article published in 1956 by Halasz and colleagues,3Halasz N.A. Halloran K.H. Liebow A.A. Bronchial and arterial anomalies with drainage of the right lung into the inferior vena cava.Circulation. 1956; 14: 826-846Crossref PubMed Scopus (95) Google Scholar the word scimitar was used for the first time to describe the shape of this anomalous pulmonary venous connection. However, it was only in 1960 that Catherine Neill and colleagues4Neill C.A. Ferencz C. Sabiston D. Sheldon H. The familial occurrence of hypoplastic right lung with systemic arterial supply and venous drainage “scimitar syndrome.”.Bull Johns Hopkins Hosp. 1960; 107: 1-21PubMed Google Scholar named the syndrome, characterizing it and linking it to the radiologic appearance of a sword adjacent to the edge of the right heart that can sometimes be found at diagnosis. The incidence of SS is relatively low, representing 3% to 6% of the partial anomalous venous connections.1Vida V.L. The Complete Reference for Scimitar Syndrome. Academic Press, London2017Google Scholar Previous studies were based on single-center experiences or rather small, multicenter studies.5Wang C.C. Wu E.T. Chen S.J. Lu F. Huang S.C. Wang J.K. et al.Scimitar syndrome: incidence, treatment, and prognosis.Eur J Pediatr. 2008; 167: 155-160Crossref PubMed Scopus (58) Google Scholar, 6Vida V.L. Speggiorin S. Padalino M.A. Crupi G. Marcelletti C. Zannini L. et al.The scimitar syndrome: an Italian multicenter study.Ann Thorac Surg. 2009; 88: 440-444Abstract Full Text Full Text PDF PubMed Scopus (37) Google Scholar, 7Vida V.L. Padalino M.A. Boccuzzo G. Tarja E. Berggren H. Carrel T. et al.Scimitar syndrome: a European Congenital Heart Surgeons Association (ECHSA) multicentric study.Circulation. 2010; 122: 1159-1166Crossref PubMed Scopus (94) Google Scholar, 8Dupuis C. Charaf L.A.C. Brevière G.M. Abou P. Rémy-Jardin M. Helmius G. The “adult” form of the scimitar syndrome.Am J Cardiol. 1992; 70: 502-507Abstract Full Text PDF PubMed Scopus (167) Google Scholar, 9Dupuis C. Charaf L.A.C. Breviere G.M. Abou P. “Infantile” form of the scimitar syndrome with pulmonary hypertension.Am J Cardiol. 1993; 71: 1326-1330Abstract Full Text PDF PubMed Scopus (109) Google Scholar, 10Dusenbery S.M. Geva T. Seale A. Valente A.M. Zhou J. Sena L. et al.Outcome predictors and implications for management of scimitar syndrome.Am Heart J. 2013; 165: 770-777Crossref PubMed Scopus (33) Google Scholar, 11Vida V.L. Padrini M. Boccuzzo G. Agnoletti G. Bondanza S. Butera G. et al.Natural history and clinical outcome of “uncorrected” scimitar syndrome patients: a multicenter study of the Italian Society of Pediatric Cardiology.Rev Española Cardiol (Engl Ed). 2013; 66: 556-560Crossref PubMed Scopus (21) Google Scholar, 12Brink J. Yong M.S. d'Udekem Y. Weintraub R.G. Brizard C.P. Konstantinov I.E. Surgery for scimitar syndrome: the Melbourne experience.Interact Cardiovasc Thorac Surg. 2015; 20: 31-34Crossref PubMed Scopus (17) Google Scholar, 13Wang H. Kalfa D. Rosenbaum M.S. Ginns J.N. Lewis M.J. Glickstein J.S. et al.Scimitar syndrome in children and adults: natural history, outcomes, and risk analysis.Ann Thorac Surg. 2018; 105: 592-598Abstract Full Text Full Text PDF PubMed Scopus (19) Google Scholar However, our group was recently able to conduct a multicenter study on behalf of the European Pediatric Cardiology Association and the European Congenital Heart Surgeons Association.14Vida V.L. Guariento A. Milanesi O. Gregori D. Stellin G. Scimitar Syndrome Study GroupThe natural history and surgical outcome of patients with scimitar syndrome: a multi-centre European study.Eur Heart J. 2018; 39: 1002-1011Crossref PubMed Scopus (21) Google Scholar This led to the collection of nearly 500 patients with SS from 51 centers, the largest series of patients with SS evaluated so far. In this review, we arbitrarily divided patients into 3 groups according to their age at diagnosis: neonates/infants (<1 year), children (between 1 and 10 years), and adolescents/adults (Table 1).Table 1Overall demographic, clinical, and instrumental data and outcomes according to the age of patients at diagnosis of a series of patients with a diagnosis of scimitar syndrome (n = 485)Adapted with permission from Vida and colleagues.14Vida V.L. Guariento A. Milanesi O. Gregori D. Stellin G. Scimitar Syndrome Study GroupThe natural history and surgical outcome of patients with scimitar syndrome: a multi-centre European study.Eur Heart J. 2018; 39: 1002-1011Crossref PubMed Scopus (21) Google ScholarOverallAge groups (at diagnosis)P valueNeonate/infants (0-1 y)Children (≥1-10 y)Adolescents/adults (≥10 y)Number of patients∗Number of patients and percentage.485 (100%)n = 282 (58%)n = 113 (23%)n = 90 (19%)Sex, male∗Number of patients and percentage.180 (37%)116 (41%)43 (38%)21 (23%).03Heart position.05 Dextrocardia∗Number of patients and percentage.240 (49%)148 (52%)61 (54%)31 (34%) Mesocardia∗Number of patients and percentage.83 (17%)48 (17%)19 (17%)16 (18%) Levocardia∗Number of patients and percentage.163 (33%)86 (30%)33 (29%)43 (48%)Isolated forms∗Number of patients and percentage.186 (38%)81 (29%)57 (50%)48 (53%).003Associated CHD∗Number of patients and percentage.299 (62%)199 (71%)60 (53%)40 (44%).003 Simple CHD∗Number of patients and percentage.198 (41%)116 (41%)49 (43%)33 (37%) Complex CHD∗Number of patients and percentage.101 (21%)83 (29%)11 (9.7%)7 (7.8%) Atrial septal defect∗Number of patients and percentage.243 (50%)156 (55%)56 (46%)35 (39%)Right pulmonary hypoplasia∗Number of patients and percentage.346 (71%)220 (78%)76 (67%)50 (55%).003Degree of right pulmonary hypoplasia.003 Mild∗Number of patients and percentage.204 (59%)115 (52%)50 (66%)39 (78%) Moderate∗Number of patients and percentage.96 (28%)65 (30%)21 (28%)10 (20%) Severe∗Number of patients and percentage.46 (13%)40 (18%)5 (6%)1 (2%)Symptoms at diagnosis∗Number of patients and percentage.353 (73%)220 (78%)73 (65%)60 (67%).047Cardiac symptoms∗Number of patients and percentage.227 (47%)168 (60%)29 (27%)30 (33%).006Respiratory symptoms∗Number of patients and percentage.243 (50%)140 (50%)59 (52%)44 (49%).99Dilated RV at diagnosis (at 2D echo)∗Number of patients and percentage.332 (68%)186 (66%)84 (74%)62 (69%).99Cardiac catheterization∗Number of patients and percentage.276 (57%)154 (55%)75 (66%)47 (52%).24 Qp/Qs†Median and interquartile range.2.1 (1.5-2.6)2.1 (1.4-2.7)1.8 (1.5-2.3)2.1 (1.6-2.2).99 mPAP, mm Hg†Median and interquartile range.24 (18-34)26 (20-40)20.5 (17-30)24 (18.5-28).006 Pulmonary hypertension∗Number of patients and percentage.157 (32%)112 (40%)28 (25%)17 (19%).006 SAS to the right lung∗Number of patients and percentage.248 (51%)182 (65%)49 (43%)17 (19%).006 Embolization of SAS∗Number of patients and percentage.177 (71%)132 (47%)33 (29%)12 (13%).006STPs∗Number of patients and percentage.279 (58%)142 (51%)78 (69%)59 (66%).03CMPs∗Number of patients and percentage.206 (42%)140 (49%)35 (31%)31 (43%)Time to last follow-up, y†Median and interquartile range.7.2 (2.2-14.0)6.4 (1.8-12.7)9.9 (3.7-17.0)7.5 (2.3-12).02Overall mortality∗Number of patients and percentage.41 (8.7%)37 (13%)4 (3.5%)–.01 STPs hospital mortality∗Number of patients and percentage.29 (10%)25 (17%)4 (5%)–.08 STPs late mortality∗Number of patients and percentage.11 (3.9%)10 (7%)1 (1.3%)–.08 CMPs mortality∗Number of patients and percentage.13 (6.3%)13 (9.3%)––.14Symptoms at follow-up∗Number of patients and percentage.172/451 (37%)109 (42%)33 (31%)30 (35%).24CHD, Congenital heart disease; RV, right ventricle; 2D, 2-dimensional; Qp/Qs, pulmonary-systemic flow ratio; mPAP, mean pulmonary artery pressure; SAS, systemic arterial supply; STPs, surgically treated patients; CMPs, clinically monitored patients.∗ Number of patients and percentage.† Median and interquartile range. Open table in a new tab CHD, Congenital heart disease; RV, right ventricle; 2D, 2-dimensional; Qp/Qs, pulmonary-systemic flow ratio; mPAP, mean pulmonary artery pressure; SAS, systemic arterial supply; STPs, surgically treated patients; CMPs, clinically monitored patients. The embryological origin of the syndrome is still unknown and may be related to a right/left disturbed signaling.15Gudjonsson U. Brown J.W. Scimitar syndrome.Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu. 2006; 9: 56-62Abstract Full Text Full Text PDF Scopus (86) Google Scholar The typical scimitar vein (SV) usually provides drainage for the entire lung in 60% of cases. This vein may be stenotic in 20% of patients with a supra or infradiaphragmatic course, representing an important factor of poor prognosis.15Gudjonsson U. Brown J.W. Scimitar syndrome.Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu. 2006; 9: 56-62Abstract Full Text Full Text PDF Scopus (86) Google Scholar Right lung hypoplasia (70% of cases) of varying degrees can be identified and is typically associated with dextrocardia (50% of cases) and systemic arterial supply (50% of cases) (Table 1). Atrial septal defect is present in 50% of the patients, but other complex congenital heart diseases (CHDs) may occur in up to 20% of patients. The remaining patients have isolated SS forms (approximately 40% of cases).14Vida V.L. Guariento A. Milanesi O. Gregori D. Stellin G. Scimitar Syndrome Study GroupThe natural history and surgical outcome of patients with scimitar syndrome: a multi-centre European study.Eur Heart J. 2018; 39: 1002-1011Crossref PubMed Scopus (21) Google Scholar The anomalous venous return inevitably leads to a left-to-right shunt, with an increase in the pulmonary-systemic flow (Qp/Qs) ratio and consequent right ventricular overload and dilation. Pulmonary arterial hypertension may occur in 30% of cases and is observed mainly in neonates/infants, in patients with CHD, and more rarely in isolated SS forms. This factor is widely recognized as one of the main determinants of poor prognosis.8Dupuis C. Charaf L.A.C. Brevière G.M. Abou P. Rémy-Jardin M. Helmius G. The “adult” form of the scimitar syndrome.Am J Cardiol. 1992; 70: 502-507Abstract Full Text PDF PubMed Scopus (167) Google Scholar,9Dupuis C. Charaf L.A.C. Breviere G.M. Abou P. “Infantile” form of the scimitar syndrome with pulmonary hypertension.Am J Cardiol. 1993; 71: 1326-1330Abstract Full Text PDF PubMed Scopus (109) Google Scholar,14Vida V.L. Guariento A. Milanesi O. Gregori D. Stellin G. Scimitar Syndrome Study GroupThe natural history and surgical outcome of patients with scimitar syndrome: a multi-centre European study.Eur Heart J. 2018; 39: 1002-1011Crossref PubMed Scopus (21) Google Scholar The diagnosis generally includes an echocardiographic evaluation in almost all patients, catheterization in more than 50% of them and, more rarely, computed tomography and magnetic resonance imaging (30% of cases). Catheterization also allows the occlusion of aberrant systemic arterial supply by embolization coils, if required by hemodynamic conditions. From an electrocardiographic point of view, 50% of cases show right ventricular hypertrophy, in the form of a right bundle branch block. Pulmonary scintigraphy may be performed and usually shows that the left lung is hyperperfused compared with the right one (76% vs 24%). The clinical presentation of SS varies and is closely related to the associated CHDs. In about 60% of cases, the diagnosis is made in children/neonates younger than the first year of age. This form, previously known as “infantile form”9Dupuis C. Charaf L.A.C. Breviere G.M. Abou P. “Infantile” form of the scimitar syndrome with pulmonary hypertension.Am J Cardiol. 1993; 71: 1326-1330Abstract Full Text PDF PubMed Scopus (109) Google Scholar is more frequently characterized by symptoms at diagnosis, such as congestive heart failure (60% of patients), failure to thrive, and tachypnea.14Vida V.L. Guariento A. Milanesi O. Gregori D. Stellin G. Scimitar Syndrome Study GroupThe natural history and surgical outcome of patients with scimitar syndrome: a multi-centre European study.Eur Heart J. 2018; 39: 1002-1011Crossref PubMed Scopus (21) Google Scholar In addition, 50% of these patients have respiratory symptoms, such as difficulty breathing, recurrent upper respiratory tract infections, cyanosis, and pneumonia. This group is also frequently affected by the presence of collateral arteries that supply the right lung and by associated CHDs. For this reason, these patients are more likely to be diagnosed early in life and treated surgically. In contrast, an “adult form” has been identified as a milder manifestation of the syndrome.8Dupuis C. Charaf L.A.C. Brevière G.M. Abou P. Rémy-Jardin M. Helmius G. The “adult” form of the scimitar syndrome.Am J Cardiol. 1992; 70: 502-507Abstract Full Text PDF PubMed Scopus (167) Google Scholar In our case series, we have divided this spectrum into 3 different subcategories based on age: neonates within 1 year, children from 1 to 10 years, and adolescents/adults older than 10 years. Fewer children were asymptomatic at diagnosis (65% of cases), with a very low percentage of cardiac symptoms (27% of cases) and pulmonary hypertension (25% of cases) (Table 1). Interestingly, we have confirmed that in more than 50% of adolescents/adults, SS appears as an isolated form, with a slight degree of right pulmonary hypoplasia, absence of symptoms in 33% of patients, or history of recurrent upper respiratory tract infections in 50% of them.14Vida V.L. Guariento A. Milanesi O. Gregori D. Stellin G. Scimitar Syndrome Study GroupThe natural history and surgical outcome of patients with scimitar syndrome: a multi-centre European study.Eur Heart J. 2018; 39: 1002-1011Crossref PubMed Scopus (21) Google Scholar Medical treatment in patients who are not directed at surgery (ie, clinically monitored patients [CMPs]) depends on the presence and type of symptoms at diagnosis. Cardiac symptoms are generally managed with diuretics and Na+/K+ ATPase inhibitors, whereas respiratory symptoms may require drugs such as beta-agonist and ipratropium bromide, antibiotics, and cortisonics. As mentioned previously, patients may present with an abnormal systemic supply to the right lung that can be treated with coil embolization, to reduce the Qp/Qs ratio. More than one half of patients (57%) are treated surgically (ie, surgically treated patients [STPs]), with an average age of about 10 years at surgery. Neonates patients are diagnosed earlier (51% of cases), particularly in the presence of cardiac symptoms and associated CHDs14Vida V.L. Guariento A. Milanesi O. Gregori D. Stellin G. Scimitar Syndrome Study GroupThe natural history and surgical outcome of patients with scimitar syndrome: a multi-centre European study.Eur Heart J. 2018; 39: 1002-1011Crossref PubMed Scopus (21) Google Scholar (Tables 1 and 2). Pulmonary hypertension (defined as a the presence of a mean pulmonary artery pressure >25 mm Hg at rest or 50% above systemic level) is often present before surgery (38% of patients) and must always be addressed before surgery, either by medical treatment or by reducing the Qp/Qs ratio by coil embolization. Therefore, isolated forms of SS are generally treated in the case of a Qp/Qs ratio >1.5:1 or Qp/Qs ratio <1.5:1 with a clinically treated pulmonary hypertension. However, the right choice for this particular group of patients remains controversial.Table 2Demographics and surgical data of a series of patients with scimitar syndrome undergoing surgery (n = 279)Mean ± SEM or nDemographics Male patients109/279 (39%) Age at surgery, mo10.2 ± 0.9 Group of age at diagnosis<1 y142/279 (51%)>1 y; <10 y78/279 (28%)> 10 y59/279 (21%)Characteristics Symptoms at diagnosis210/279 (76%)Cardiac symptoms at diagnosis147/279 (53%)Respiratory symptoms at diagnosis142/279 (51%) Need for medications at diagnosis48/279 (17%) Pulmonary hypertension at diagnosis105/279 (38%) mPAP at diagnosis, mm Hg29.2 ± 0.1 Associated CHDs194/279 (69%)Atrial septal defect168/279 (60%)Complex CHDs63/279 (23%) SAS to the right lung130/279 (47%) Coil embolization of SAS93/279 (33%) Degree of right pulmonary hypoplasiaMild110/279 (39%)Moderate61/279 (22%)Severe18/279 (6%)Operative data Type of procedureCorrective surgery254/279 (91%)Resective25/279 (9%) Type of corrective surgeryIntracardiac baffle176/254 (69%)Direct scimitar vein reimplantation78/254 (31%) Type of resective surgeryLobectomy18/25 (72%)Pneumectomy7/25 (28%) Associated surgical procedure101/279 (36%) CBP time, min127.2 ± 5.4 Aortic crossclamp time, min62.5 ± 3.2 Circulatory arrest time, min28.3 ± 6.4SEM, Standard of the mPAP, mean pulmonary artery pressure; CHD, congenital heart disease; SAS, systemic arterial supply; Open table in a new tab Standard of the mPAP, mean pulmonary artery pressure; CHD, congenital heart disease; SAS, systemic arterial supply; treatment includes of abnormal venous drainage in patients but right lung may be required in more forms. In the abnormal systemic supply to the right lung be and all associated be for the of the anomalous in the left can of of cases) or of cases).14Vida V.L. Guariento A. Milanesi O. Gregori D. Stellin G. Scimitar Syndrome Study GroupThe natural history and surgical outcome of patients with scimitar syndrome: a multi-centre European study.Eur Heart J. 2018; 39: 1002-1011Crossref PubMed Scopus (21) Google Scholar are surgical corrective for the pulmonary venous return S. M. Y. S. Scimitar syndrome: the Thorac Cardiovasc Surg Pediatr Card Surg Annu. Full Text Full Text PDF PubMed Scopus Google Scholar can be a right or 1). of the first described the of a flow from the of the at the of the the right and the of the to the of the septal P. of anomalous pulmonary venous Surg. PubMed Google Scholar includes the of the with a of the and in the left and S. Scimitar syndrome: surgical to an of the scimitar Pediatr Cardiol. 9: PubMed Scopus Google Scholar Brown and J.W. M. P. C.A. et management of scimitar syndrome: an Thorac Cardiovasc Surg. Full Text Full Text PDF PubMed Scopus Google Scholar described a of the with of the of the and a to the new have been such that by and A new surgical to scimitar Thorac Surg. Full Text Full Text PDF PubMed Scopus (17) Google Scholar in the pulmonary venous return is widely to the left a with the in The shows the Scimitar septal inferior vena left the of a right pulmonary or more rarely a right pulmonary has been to the presence of right pulmonary hypoplasia, recurrent upper respiratory tract infections to medical treatment, or corrective surgery. occur in 33% of the patients and usually respiratory failure (39%) and congestive heart failure The hospital is generally low and for patients undergoing corrective surgery rather than resective is at a mean of years, with an of of the patients. at years of age is and is in patients with associated and pulmonary hypertension. In the STPs, of the are by congestive heart failure but also by pulmonary hypertension and respiratory failure STPs are asymptomatic at the last clinical and only 20% of patients still medications (Table In contrast, is a slight increase in patients in clinically monitored patients to for cardiac and respiratory of the asymptomatic patients at diagnosis symptoms surgical V.L. Guariento A. Milanesi O. Gregori D. Stellin G. Scimitar Syndrome Study GroupThe natural history and surgical outcome of patients with scimitar syndrome: a multi-centre European study.Eur Heart J. 2018; 39: 1002-1011Crossref PubMed Scopus (21) Google of a series of scimitar syndrome patients undergoing surgery (n = 279)Mean ± SEM or outcomes heart in case of corrective in case of resective outcomes heart Symptoms at symptoms at symptoms at Need for medications at Scimitar vein in case of corrective from ± Standard of the Open table in a new tab Standard of the almost one of the STPs present drainage a corrective This in of cases or rarely occlusion in of patients. This diagnosis is not related to the type of corrective V.L. Guariento A. Milanesi O. Gregori D. Stellin G. Scimitar Syndrome Study GroupThe natural history and surgical outcome of patients with scimitar syndrome: a multi-centre European study.Eur Heart J. 2018; 39: 1002-1011Crossref PubMed Scopus (21) Google Scholar used and is more in neonates/infants (33%) than in either children (20%) or adolescents/adults In addition, we found that is an age at and of the scimitar drainage younger the the the incidence of V.L. Guariento A. Milanesi O. Gregori D. Stellin G. Scimitar Syndrome Study GroupThe natural history and surgical outcome of patients with scimitar syndrome: a multi-centre European study.Eur Heart J. 2018; 39: 1002-1011Crossref PubMed Scopus (21) Google Scholar For this reason, an is usually in younger patients whereas is in older these patients with an cardiac catheterization or to the with average of more than years from the time of the first surgery In patients with of the a is and is often the first of this The clinical presentation of patients with SS mainly on age at diagnosis and associated CHDs. Pulmonary hypertension and the presence of associated are in of

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