Prophylactic effect of angiotensin receptor blockers in children with genetic aortopathies: the early bird catches the worm

AIMS

In genetic aortopathies (GA) particular attention is paid to aortic root dilatation which has an impact on morbidity and mortality. This study focuses on the effects of therapy with angiotensin-II-receptor-blockers (ARB) or beta-blockers (BB) on aortic root growth and the question which therapy should be initiated at which dosage and at what age.

METHODS

Since 1998 we diagnosed 208 patients with GA (170 FBN-1). 81 patients between 5 months and 18 years receiving either ARB or BB therapy were included. We retrospectively analyzed the progression of the dilatation of Sinus Valsalva aortae (SV) using calculated z-scores before and after therapy initiation and compared BB and ARB treatment.

RESULTS

Both ARB and BB (p < 0.05) therapy showed significant improvement in aortic root growth, while the effect is significantly more pronounced in ARB (p < 0.01) independent of age and genetic cause. A detailed comparison of the two drug groups showed a more sustained effect in limiting the progression of the dilatation of the aortic root in patients treated with ARB. Progression of dilatation of the SV was significantly lower in children treated with ARBs compared to BB (delta z-score, p < 0.05). In addition, ARBs were better tolerated and had a significantly lower discontinuation rate (3%) compared to BB (50%) (p < 0.01). Independently of age at initiation all children and adolescents were able to reach the target dose under ARB.

CONCLUSION

We demonstrated a significant change in both treatment options, with the effect of ARB being more pronounced while being better tolerated throughout the treatment period.

[Vascular surgery in old people]

The age pyramid in Germany is upside down. According to the Federal Statistical Office this development will continue in the coming years, which presents a challenge for surgeons to surgically treat increasingly more and increasingly older people. Particularly in vascular surgery, which is a surgery of old people, this fact represents a special challenge. The frailty of old people is, among other things, due to a series of comorbidities, which must be taken into consideration within the framework of surgical treatment. They can have an important influence on the perioperative planning, the operation, the postoperative treatment and the outcome of the patient. This treatment planning becomes more and more challenging, because due to the progress in endovascular surgery there will soon be no limits to what is feasible; however, the question arises whether the feasible is also reasonable? Within the scope of this article the authors try to give answers to the treatment of old patients in vascular surgery and to find strategies for planning and to establish an individualized optimal treatment.

[Medical care of adults with congenital heart diseases : Present and future]

Congenital heart diseases (CHD) are the most common types of congenital organ defects. Thanks to medical progress in congenital cardiology and heart surgery, most children with CHD reach adulthood. Despite primarily successful treatment residual and subsequent conditions as well as (non)cardiac comorbidities can influence the chronic course of the disease and lead to a higher morbidity and mortality. Adults with congenital heart disease (ACHD) in Germany are not tied to the healthcare structure despite the great need for aftercare. According to the results of the medical care of ACHD (MC-ACHD) study, ACHD centers and specialists in Germany are insufficiently perceived despite increased complication rates and the great need for specialist guidance. General practitioners and patients are not adequately informed about existing ACHD facilities. A better awareness of the ACHD problem should be created at the level of primary medical supply in order to optimize care and to reduce morbidity and mortality. Improved future-oriented patient care includes lifelong regular follow-up and the possibility of interdisciplinary, integrated medical care of CHD.

Does statin therapy impact the proximal aortopathy in aortic valve disease?

BACKGROUND

Studies have demonstrated that statin therapy decreases the growth rate of abdominal aneurysms. However, the effect of statin therapy on the proximal aortic disease has not been sufficiently elucidated.

AIM

We aimed to analyse the association between statin treatment and the severity of proximal aortopathy in patients with aortic valve disease.

DESIGN

Cross-sectional study.

METHODS

We prospectively identified 458 patients who were referred for aortic valve surgery from 2008 to 2014. Pre-operative measurement of the proximal aorta was performed by TEE, CT or MRT scan. Data of dyslipidemia treatment was obtained by questionnaire.

RESULTS

The mean ascending aortic diameter in the whole study population was comparable in patients with vs. without statin therapy (i.e. 42.7 mm vs. 43.6 mm, P = 0.46). Logistic regression analysis showed no significant association between statin therapy and proximal aortopathy ≥ 40 mm in the whole study group (OR = 0.69, P = 0.10). For the BAV sub-group, HDL (OR = 0.54, P = 0.038) and cholesterol levels (OR = 2.00, P = 0.038) were found significantly associated with the proximal aortic disease. In the BAV cohort, the statin users with target HDL levels presented a significantly smaller proximal aortic diameter (40.1 mm vs. 46 mm, P = 0.02).

CONCLUSION

Pre-operative statin therapy demonstrated no significant association with the expression of proximal aortopathy. However, more than 40% of the statin users presented uncontrolled lipid levels at the time of the study. In the BAV sub-group, the statins users with target HDL levels showed a significantly smaller ascending aorta diameter. Target HDL and cholesterol levels were strongly associated with proximal aortic dilation in BAV patients.

[Genetics and prevention of genetic aortic syndromes (GAS) and of the Marfan syndrome]

BACKGROUND

Genetic aortic syndromes are autosomal-dominantly heritable aneurysms of the thoracic aorta, which carry a high risk of aortic rupture or acute thoracic aortic dissection at young age.

OBJECTIVES

We introduce the reader to the principles of genetic diagnostics and the medical and surgical prevention of thoracic aortic dissection in patients with genetic aortic syndromes.

METHODS

A cardiologist, a health economist, a patient representative, a heart surgeon, and a molecular geneticist teamed up to elucidate their perspective on major aspects of genetics and prevention of genetic aortic syndromes.

RESULTS

Genetic aortic syndromes reflect a broad spectrum of diverse disease entities comprising the Marfan syndrome, the Loeys-Dietz syndrome or the vascular Ehlers-Danlos syndrome. The diagnosis of each respective disease entity requires combined assessment of phenotype and genotype information. A medical prevention of aortic complications such as dissection is mandatory although a curative therapy currently appears unlikely in humans. The single most important measure against acute aortic dissection is the preventive replacement of the aortic root, where valve preserving techniques appear preferable. Comprehensive prophylaxis including molecular diagnostics seem reasonable also from an economic point of view.

DISCUSSION

Optimal prevention requires individualization of concepts, which entail a detailed diagnostic characterization of each specific genetic aortic syndrome including characterization of the genotype.

[Transcardiac Access Routes for Endovascular Treatment of Ascending Aortic Pathologies]

Gold standard for treatment of pathologies of the ascending aorta is still open surgery with extracorporal circulation in moderate to deep hypothermia. These procedures are associated with high morbidity and mortality, especially if performed in older patients or after previous cardiac surgery. Thoracic endovascular aortic repair (TEVAR) has become the preferred treatment option for thoracic aortic pathologies of the descending aorta even in high-risk patients with severe comorbidities resulting in reduced morbidity and mortality compared to open repair. Despite the continuous development of endograft technology an adequate arterial access still poses a relevant limitation of this treatment option accentuated in the proximal segments of the aorta. The transfemoral access may be limited due to severe kinking or arteriosclerotic plaque stenosis of femoral or iliac vessels. Furthermore, the long distance between femoral access vessels and the aortic lesion impairs device torsibility and exact deployment of the stent graft. To provide a practical alternative endovascular access to the ascending aorta, antegrade transcardiac access routes including transapical or transseptal techniques have recently gained increasing interest.

Acute aortic syndromes: definition, prognosis and treatment options

Acute aortic syndromes (AAS) are life-threatening vascular conditions of the thoracic aorta presenting with acute pain as the leading symptom in most cases. The incidence is approximately 3-5/100,000 in western countries with increase during the past decades. Clinical suspicion for AAS requires immediate confirmation with advanced imaging modalities. Initial management of AAS addresses avoidance of progression by immediate medical therapy to reduce aortic shear stress. Proximal symptomatic lesions with involvement of the ascending aorta are surgically treated in the acute setting, whereas acute uncomplicated distal dissection should be treated by medical therapy in the acute period, followed by surveillance and repeated imaging studies. Acute complicated distal dissection requires urgent invasive treatment and thoracic endovascular aortic repair has become the treatment modality of choice because of favorable outcomes compared to open surgical repair. Intramural hematoma, penetrating aortic ulcers, and traumatic aortic injuries of the descending aorta harbor specific challenges compared to aortic dissection and treatment strategies are not as uniformly defined as in aortic dissection. Moreover these lesions have a different prognosis. Once the acute period of aortic syndrome has been survived, a lifelong medical treatment and close surveillance with repeated imaging studies is essential to detect impending complications which might need invasive treatment within the short-, mid- or long-term.

Dural ectasia in Loeys-Dietz syndrome: comprehensive study of 30 patients with a TGFBR1 or TGFBR2 mutation

The purpose of this study was to assess the frequency, severity, and clinical associations of dural ectasia (DE) in Loeys-Dietz syndrome (LDS). Database analysis of three German metropolitan regions identified 30 patients with LDS and TGFBR1 mutation in 6 and a TGFBR2 mutation in 24 individuals (17 men; mean age: 31 ± 19 years), as well as 60 age and sex-matched control patients with Marfan syndrome carrying a FBN1 mutation. DE was present in 22 patients with LDS (73%), and it related to skeletal score points (p = 0.008), non-skeletal score points (p < 0.001), and to the presence of ≥7 systemic score points (p = 0.010). Similarly, the severity of DE was related to body height (p = 0.010) and non-skeletal score points (p = 0.004). Frequency (p = 0.131) and severity of DE (p = 0.567) was similar in LDS and Marfan syndrome. DE is a manifestation of LDS that occurs with similar frequency and severity as in Marfan syndrome. Severity of DE may serve as a marker of the overall connective tissue disease severity. LDS may be considered in patients with DE.

Comprehensive analysis of dural ectasia in 150 patients with a causative FBN1 mutation

The purpose of this study was to perform a comprehensive study of dural ectasia (DE) related to FBN1 mutations. We performed a database analysis of two German metropolitan regions of 150 patients (68 men, 82 women; mean age 35 ± 16 years). All patients had a FBN1 mutation and underwent dural magnetic resonance imaging. Age was <16 years in 20, 16-25 in 27, 26-35 in 67, and >35 in 36 patients. Prevalence of dural ectasia was 89% with criteria of Oosterhof and Habermann, 83% with Fattori, 78% with Lundby, and 59% with Ahn. DE was less frequent in patients <16 years with Ahn and Fattori. DE related to skeletal manifestations with all criteria, to aortic Z-scores and mitral valve prolapse with criteria of Habermann and Lundby, and to age with criteria of Fattori. The Fattori-grade of DE increased with age, aortic Z-scores, and skeletal score points. There was no consistent relationship of DE with any type of FBN1 mutation. DE is frequent in patients with FBN1 mutations irrespective of age and its severity increases during life. Criteria of Oosterhof and Habermann yielded most consistent diagnostic results. DE relates to skeletal involvement, aortic Z-scores, and mitral valve prolapse.

Pediatric patients with Marfan syndrome: frequency of dural ectasia and its correlation with common cardiovascular manifestations

PURPOSE

Marfan syndrome (MFS) is a genetic disorder of the connective tissue. Aortic root dilation is a main criterion of the Ghent Nosology. Dural ectasia and the presence of mitral valve prolapse (MVP) contribute to its systemic score. The purpose of this study was to investigate the frequency of dural ectasia and its correlation with cardiovascular manifestations in a pediatric study population.

PATIENTS AND METHODS

119 pediatric patients with confirmed or suspected MFS were examined in the local Marfan Clinic. 31 children with MFS who underwent magnetic resonance imaging (MRI) were included. Each patient was evaluated according to the Ghent nosology. Echocardiography was used to measure the aortic root diameter and assess the presence of MVP and mitral regurgitation. Z-scores were calculated for the evaluation of the aortic root diameters. MRI was performed to determine the dural sac ratio (DSR).

RESULTS

The prevalence of dural ectasia was 90.3 %, of aortic root dilation 32.2 %, of MVP 64.5 % and of mitral regurgitation 51.6 %. DSR at L5 correlated with the intraindividual z-scores (slope, 3.62 ± 1.5 [0.56; 6.68]; r = 0.17; p = 0.02; F = 5.84). Z-scores ≥ 2 were accompanied by dural ectasia in 100 %, MVP in 95 % and mitral regurgitation in 100 % of cases. MVP was accompanied by mitral regurgitation in 70 % of cases.

CONCLUSION

As the examined cardiac manifestations show a coincidence with dural ectasia in 95 - 100 % of cases, MRI for diagnostic dural sac imaging should be reserved for MFS suspicions with the absence of those manifestations in order to establish the diagnosis according to the Ghent criteria. Thus, the present study supports the recent downgrading of dural ectasia to a contributor to the systemic score.

A simple clinical model to estimate the probability of Marfan syndrome

BACKGROUND

Marfan syndrome is a heritable connective tissue disease. Definitive diagnosis is complex, and requires sequencing of a large gene, FBN1.

AIM

We aimed to develop a simple model to estimate the pre-test probability of Marfan syndrome.

DESIGN

Prospective cross-sectional study.

METHODS

We applied diagnostic standards for definitive diagnosis or exclusion of Marfan syndrome in 329 consecutive persons. In 208 persons with random assignment to our derivation group, we performed multivariate logistic regression to assess 14 clinical variables for inclusion in a prediction model with derivation of score points from the estimated coefficients. We created cut-offs to classify low, moderate and high probability of Marfan syndrome. For validation, we applied the model to the remaining 121 persons.

RESULTS

We identified seven variables for inclusion in the final model, where we assigned four score points to ectopia lentis, two points to a family history of Marfan syndrome, and one point to previous thoracic aortic surgery, to pectus excavatum, to a wrist and thumb sign, to previous pneumothorax, and to skin striae. In the derivation group 12, 42 and 92% of persons with low (≤1 point), moderate (>1-3.5 points) or high pre-test probability (>3.5 points) had Marfan syndrome, compared to 12, 57 and 91%, respectively, in the validation group. Positive likelihood ratios were 13.96 and 8.54 in the high probability group of the derivation and validation group, respectively.

CONCLUSION

A simple prediction model provides evidence for Marfan syndrome. This model can be used to identify patients who require definitive diagnostic work-up.

Analysis of phenotype and genotype information for the diagnosis of Marfan syndrome

Marfan syndrome is considered a clinical diagnosis. Three diagnostic classifications comprising first, Marfan genotype with a causative FBN1 gene mutation; second, Marfan phenotype with clinical criteria of the original Ghent nosology (Ghent-1); and third, phenotype with clinical criteria of its current revision (Ghent-2) in 300 consecutive persons referred for confirmation or exclusion of Marfan syndrome (150 men, 150 women aged 35 ± 13 years) were used. Sequencing of TGBR1/2 genes was performed in 128 persons without FBN1 mutation. Marfan genotype was present in 140, Ghent-1 phenotype in 139, and Ghent-2 phenotype in 124 of 300 study patients. Marfan syndrome was confirmed in 94 and excluded in 129 persons consistently by all classifications, but classifications were discordant in 77 persons. With combined genotype and phenotype information confirmation of Marfan syndrome was finally achieved in 126 persons by Ghent-1 and in 125 persons by Ghent-2 among 140 persons with Marfan genotype, and exclusion was accomplished in 139 persons by Ghent-1 and in 141 persons by Ghent-2 among 160 persons without Marfan genotype. In total, genotype information changed final diagnoses in 22 persons with Ghent-1, and in 32 persons with Ghent-2. It is concluded that genotype information is essential for diagnosis or exclusion of Marfan syndrome.

Dural ectasia in individuals with Marfan-like features but exclusion of mutations in the genes FBN1, TGFBR1 and TGFBR2

Mutations in the genes FBN1, TGFBR1, and TGFBR2 can result in heritable connective tissue disorders comprising the Marfan syndrome and the Loeys-Dietz syndrome. Dural ectasia is a characteristic manifestation of both syndromes. However, dural ectasia has not yet been investigated in connective tissue disorders that are unrelated to mutations in the FBN1, TGFBR1 or TGFBR2 genes. Here, we assessed dural ectasia in 33 individuals both with typical manifestations of heritable connective tissue disease and in whom mutations in all three genes had been excluded. We identified 19 individuals with dural ectasia (58%), who exhibited major skeletal manifestations of the Marfan syndrome more frequently than the remaining 14 persons without dural ectasia (p = 0.06). Moreover, only persons with dural ectasia fulfilled clinical criteria of the Marfan syndrome (p = 0.01). Conversely, aortic aneurysm (12 patients; p = 0.8), aortic dissection (five patients; p = 0.1), spontaneous dissection of the carotid arteries (five patients; p = 1), and mitral valve prolapse (13 patients; p = 0.4) were similarly frequent irrespective of dural ectasia. We conclude that dural ectasia is a marker for connective tissue disease which coincides with skeletal rather than with cardiovascular manifestations, and which may involve currently uncharacterized pathogenetic mechanisms and syndromes.

Marfan syndrome and the evolving spectrum of heritable thoracic aortic disease: do we need genetics for clinical decisions?

Marfan syndrome (MFS) is a disorder of the connective tissue that is inherited in an autosomal dominant fashion and that is classically caused by mutations in the gene coding for fibrillin-1, FBN1. The high mortality of untreated MFS results almost exclusively from aortic complications such as aortic dissection and rupture. However, more than half of patients with Marfan-like features do not have MFS, but have other diseases including inherited aortic aneurysms and dissections (TAAD). We elucidate the increasing spectrum of syndromes associated with Marfan-like features and discuss the clinical implications of these diseases. We performed a systematic review to tabulate all known inherited diseases and syndromes carrying a risk for thoracic aortic disease. We discuss evidence that different syndromes with different causative genes and mutations have different prognoses and profiles of cardiovascular manifestations. We conclude that future decisions for optimized management of patients with inherited TAAD require a comprehensive clinical and genetic work-up.

Neuro-kardio-fazio-kutane Syndrome

Neuro-kardio-fazio-kutane („neuro-cardio-facio-cutaneous“: NCFC) Syndrome wurden in den letzten Jahren als eine Gruppe von angeborenen Erkrankungen definiert, deren phänotypische Überschneidungen eine gemeinsame pathogenetische Grundlage haben. Erkrankungen aus diesem phänotypischen Spektrum gehen mit einer Überfunktion des RAS-MAPK-Signalwegs (RAS: „rat sarcoma“, MAPK mitogenaktivierte Proteinkinase) einher. Zu den neuro-kardio-fazio-kutanen Erkrankungen gehören das Noonan-, das LEOPARD-, das kardio-fazio-kutane („cardio-facio-cutaneous“: CFC) und das Costello-Syndrom, die Neurofibromatose Typ 1 sowie das Legius-Syndrom. Für eine sachgerechte medizinische Diagnostik und Behandlung sowie die notwendige psychosoziale Betreuung von Betroffenen und deren Familien ist das Zusammenwirken verschiedener Fachdisziplinen notwendig.

Aneurysms of the ascending aorta: diagnostic features and prognosis in patients with Marfan's syndrome versus hypertension

BACKGROUND

In Marfan's syndrome progressive dilation of the sinuses of Valsava, the supra-aortic ridge and the ascending aorta are well characterized abnormalities likely to set the stage for severe aortic sequelae accounting for 70% of lethal complications. However, the specific anatomical, clinical, and prognostic profiles of aortic pathology are less well characterized in the setting of patients with Marfan's syndrome symptomatic from aortic complications.

HYPOTHESIS

The study was designed to characterize the spectrum of anatomical, clinical, and prognostic profiles of thoracic aortic disease in symptomatic patients with Marfan's syndrome compared with patients with arterial hypertension. Noninvasive imaging techniques were used for comprehensive mapping of aortic pathology associated with Marfan's syndrome.

METHODS

Thirty-five consecutive patients with Marfan's syndrome (16 women, 19 men; mean age 35 +/- 12 years) were imaged by transthoracic (TTE; n = 26) and transesophageal echocardiography (TEE; n = 11), contrast enhanced computed tomography (XCT; n = 16), or magnetic resonance techniques (MRI; n = 14). Diagnostic results were compared with both intraoperative or angiographic findings and also with a group of 85 consecutive patients with aortic pathology associated with arterial hypertension.

RESULTS

Aortic pathology was more frequently confined to the ascending aorta (p < 0.05) and aortic regurgitation was more prevalent in Marfan's syndrome than in arterial hypertension (p < 0.05). In 23 cases (66%) of dissection and 12 cases (34%) of nondissecting aneurysms, no Marfan-specific aortic macropathology was identified when compared with arterial hypertension. Diagnostic results of TEE, XCT, and MRI were all excellent; however, in contrast to the transesophageal ultrasound approach, transthoracic ultrasound was not useful in the detection of aortic dissection and intramural hemorrhage. Both 30-day (100 vs. 70%; p < 0.05) and 5-year survival rates (91 vs. 57%; NS) were higher in patients with Marfan's syndrome than in those with arterial hypertension. Repeat surgery, however, was more frequently required in patients with Marfan's syndrome (25% vs. none in aortic aneurysm; p < 0.05).

CONCLUSIONS

There are no macropathologic findings of the aorta specific for Marfan's syndrome. In patients with Marfan's syndrome with an inherently high rate of aortic complications, serial noninvasive imaging should be encouraged, preferably utilizing TEE or MRI.

Predicting severity of haemophilia A and B splicing mutations by information analysis

Bleeding symptoms and clotting activity vary among mutations that alter mRNA splicing of either the factor VIII or factor IX genes. We analyzed splicing mutations in both genes for changes in individual information (R(i), in bits) involving both donor or acceptor sites. Mutations with low or negative R(i) values (<2.4 bits) or significant changes in R(i) (DeltaR(i) > or = 7 bits) exhibited either reduced protein activity, increased clotting time and bleeding frequency and were predictive of severe disease. Thus, information analysis of splicing mutations may be useful in predicting phenotypes in hemophilia.

Coronary artery anomalies. Part I: Recent insights from molecular embryology

Congenital anomalies of the coronary arteries occur in 0.2-1.2% of the general population and may cause substantial cardiovascular morbidity and mortality. We review some of the advances that have been made both, in the understanding of the embryonic development of the coronary arteries (part I) and in the clinical diagnosis and management of their anomalies (part II). In this first part of our review we elucidate basic mechanisms of coronary vasculogenesis, angiogenesis and embryonic arteriogenesis. Moreover, we review the role of cellular progenitors such as epicardium-derived cells, cardiac neural crest cells and cells of the peripheral conduction system. Then we discuss the role of growths factors (such as FGV, HIF 1, PDGF B, TGFbeta1, VEGF, and VEGFR-2) and genes (such as FOG-2, VCAM-1, Bves, and RALDH2) at different states of coronary development. and we discuss the role of the cardiac neural crest in the concurrence of coronary anomalies with aortic root malformations. This part of the article is designed to review major determinants of coronary vascular development to provide a better understanding of the multiplicity of options and mechanisms that may give rise to coronary anomaly. To this end, we highlight results from experiments that provide insight in mechanisms of coronary malformation.

Coronary artery anomalies Part II: recent insights from clinical investigations

Congenital anomalies of the coronary arteries occur in 0.2-1.2% of the general population; they cause 12% of sports-related sudden cardiac deaths and 1.2% of non-sports-related deaths. We review some of the substantial advances that have been made both, in the understanding of the embryonic development of the coronary arteries and in the clinical diagnosis and management of their anomalies. In this second part of our review we elucidate recent approaches to defining coronary anomalies and provide information on their incidence and prognosis. In addition, we discuss the options for screening large populations for potentially lethal coronary malformations and elucidate the role of invasive diagnostic modalities such as intravascular ultrasound, flow wire and pressure wire. The clinical relevance of coronary anomalies is discussed particularly for the ill-defined group of anomalies that only occasionally cause severe clinical events comprising anomalous origination of a coronary artery from the opposite sinus (ACAOS), coronary artery fistulae and myocardial bridging. Finally, we provide an update on current diagnostic and therapeutic recommendations.

[Clinical diagnosis of acute aortic dissection]

Despite the availability of modern imaging technology, 35% of aortic dissections remain undiagnosed in vivo because clinical criteria for aortic dissection are not available to date. The present study analyzed 250 patients with acute chest and/or back pain, absence of an established differential diagnosis of the pain syndrome and clinical suspicion of acute aortic dissection for presence of 26 clinical variables. Multivariate analysis identified an aortic pain syndrome with immediate onset and/or tearing or ripping character (P < 0.0001), mediastinal and/or aortic widening on chest radiography (P < 0.0002) and pulse- and/or blood pressure differentials (P < 0.0001) as predictors of acute aortic dissection. Probability of dissection was low (7%) with absence of all three variables, intermediate (31 and 39%, respectively) with isolated findings of "aortic pain" or "mediastinal widening", and high (> 83%) with either isolated "pulse- and/or blood pressure differentials" or any combination of the three variables. This model appears useful to improve selection of patients for emergency imaging of the thoracic aorta.

[Splice site mutations and atherosclerosis: mechanisms and prediction models]

Nucleotide variants in genes of the lipid metabolism influence the risk of premature atherosclerosis. Ten percent of all single nucleotide substitutions in these genes involve splice sites. The effects of these changes on mRNA splicing and phenotypic severity, however, are not inherently obvious from the nucleotide sequence. This review presents various genes of lipid metabolism with splicing mutations known to influence the risk of premature atherosclerosis. Mechanisms of pre-mRNA splicing are illustrated and different models for prediction of the effect of nucleotide substitutions on splice-site function are presented. The role of information theory-based models is emphasized along with its role for prediction of splice-site function and phenotypic severity of atherosclerosis.

Proximal aortic dissection late after aortic valve surgery: 119 cases of a distinct clinical entity

BACKGROUND

Besides systemic hypertension and Marfan syndrome, only previous aortic valve replacement (AVR) is independently associated with proximal (type A) aortic dissection. Little, however, is known to date about the characteristic features of this clinical entity.

METHODS

Clinical, prognostic and predisposing profiles in 119 cases of dissection and/or aneurysm occuring 1 month to 16 years after routine AVR were analyzed comprising 62 cases from our database and 57 reported cases.

RESULTS

Dissection after AVR has been observed in 0.6% of all routine AVR procedures in the past four decades. With clinical signs, symptoms and anatomical features different from classic aortic dissection post-AVR dissection is a distinct clinical entity with a high intraoperative mortality of 44% and a 30-day and 5-year survival of 62% and 43%, respectively. Aortic regurgitation and a thin and/or fragile aortic wall at AVR, however, predict late dissection. Using a prediction model, the risk of late dissection can be stratified based on information obtained during AVR surgery.

CONCLUSIONS

Aortic dissection following AVR is likely to represent a distinct clinical entity which can be predicted and possibly prevented at AVR.

Clinical prediction of acute aortic dissection

BACKGROUND

Clinical criteria for aortic dissection are poorly defined. Thus, 35% of aortic dissections remain unsuspected in vivo, and 99% of suspected cases can be refuted.

OBJECTIVE

To identify independent predictors of acute aortic dissection and create a prediction model for facilitated estimation of the individual risk of dissection.

METHODS

Two hundred fifty patients with acute chest pain, back pain, or both; absence of an established differential diagnosis of the pain syndrome; and clinical suspicion of acute aortic dissection were evaluated for the presence of 26 clinical variables in a prospective, observational study. Multivariate analysis was performed to create a prediction model of aortic dissection.

RESULTS

Aortic pain with immediate onset, a tearing or ripping character, or both; mediastinal widening, aortic widening, or both on chest radiography; and pulse differentials, blood pressure differentials, or both (P<.001 for all) were identified as independent predictors of acute aortic dissection. Probability of dissection was low with absence of all 3 variables (7%), intermediate with isolated findings of aortic pain or mediastinal widening (31% and 39%, respectively), and high with isolated pulse or blood pressure differentials or any combination of the 3 variables (> or = 83%). Accordingly, 4% of all dissections were assigned to the low-probability group, 19% to the intermediate-probability group, and 77% to the high-probability group of aortic dissection.

CONCLUSIONS

Assessment of 3 clinical variables permitted identification of 96% of the acute aortic dissections and stratification into high-, intermediate-, and low-probability groupings of disease. With better selection for prompt diagnostic imaging, this prediction model can be used as an aid to improve patient care in aortic dissection. Arch Intern Med. 2000;160:2977-2982

Clustering of mutations associated with mild Marfan-like phenotypes in the 3' region of FBN1 suggests a potential genotype-phenotype correlation

Mutations in the gene for fibrillin-1 (FBN1) cause Marfan syndrome, a dominantly inherited disorder of connective tissue that primarily involves the cardiovascular, ocular, and skeletal systems. There is a remarkable degree of variability both within and between families with Marfan syndrome, and FBN1 mutations have also been found in a range of other related connective tissue disorders collectively termed type-1 fibrillinopathies. FBN1 mutations have been found in almost all of the 65 exons of the FBN1 gene and for the most part have been unique to one affected patient or family. Aside from the "hot spots" for the neonatal Marfan syndrome in exons 24-27 and 31-32, genotype-phenotype correlations have been slow to emerge. Here we present the results of temperature-gradient gel electrophoresis analysis of FBN1 exons 59-65. Six mutations were identified, only one of which had been previously reported. Two of the six mutations were found in patients with mild phenotypes. Taken together with other published reports, our results suggest that a sizable subset (ca. 40%) of mutations in this region is associated with mild phenotypes characterized by the lack of significant aortic pathology, compared with about 7% in the rest of the gene. In two cases, mutations affecting analogous positions within one of the 43 cbEGF modules of FBN1 are associated with mild phenotypes when found in one of the 6 C-terminal modules (encoded by exons 59-63), but are associated with classic or severe phenotypes when found in cbEGF modules elsewhere in the gene.

Predictors of proximal aortic dissection at the time of aortic valve replacement

BACKGROUND

Type I aortic dissection develops in 0.6% of patients late after aortic valve replacement (AVR), and 13% of patients with type I aortic dissections have a history of AVR. Predictors of aortic dissection at AVR, however, have not been characterized.

METHODS AND RESULTS

A study group of 33 patients with type I aortic dissection had aortic surgery 49+/-55 months after routine AVR. A group of 101 controls, who did not have morphological progression of aortic diameters >/=6 years after AVR, was used to identify predictors of postsurgical dissection. Multivariate analysis identified aortic regurgitation (P<0.002) and fragility (P<0.001) or thinning of the aortic wall (P<0.007) at AVR as predictors, associated with a 14%, 22%, and 7% probability of late aortic dissection, respectively. Clamping times, types of valve prostheses, concomitant coronary artery bypass grafting, and mean ascending aortic diameters of 43+/-10 mm at AVR did not predict late dissection. A separate analysis of 29 nondissecting aneurysms of the ascending aorta developing 104+/-64 months after routine AVR revealed younger age at AVR (P<0.003) and congenitally bicuspid aortic valves (P<0.03) as predictors of late aneurysm formation.

CONCLUSIONS

Aortic regurgitation combined with fragile and thinned aortic walls in patients with moderate aortic dilation may reflect aortic root disease, with a high risk for postsurgical aortic sequelae if it is treated incompletely by isolated valve replacement.

Comparison of heteroduplex analysis, direct sequencing, and enzyme mismatch cleavage for detecting mutations in a large gene, FBN1

Analysis of large genes for mutations of clinical relevance is complicated by intragenic heterogeneity, sensitivity, and cost of the methods available, and in the case of many conditions, specificity of the genetic alterations detected. We examined the FBN1 gene for mutations in people who had Marfan syndrome using three methods: single-chain polymorphism analysis (SSCP) with heteroduplex (HA) analysis, enzyme-mediated cleavage (EMC) of heteroduplexes, and direct sequencing. We also used these methods to search for mutations in the P53 gene in patients with hepatocellular carcinoma. The results showed that EMC was most efficient for detecting mutations. However, the cost favored SSCP with heteroduplex analysis, provided conditions did not need to be optimized to detect a mutation. Until more cost-effective and sensitive methods are developed to detect unknown mutations in large genes, diagnosis of many genetic disorders will depend on the willingness of an investigator who is studying a particular disorder to perform clinical molecular testing and have the laboratory accredited.

Importance of dural ectasia in phenotypic assessment of Marfan's syndrome

BACKGROUND

Early identification of Marfan's syndrome is fundamental in the prevention of aortic dilatation, but the wide phenotypic expression of the disorder makes the clinical diagnosis very difficult. Dural ectasia has been classified as a major diagnostic criterion; however, its prevalence is not known. We aimed to identify the true prevalence of dural ectasia in Marfan's syndrome, and to investigate its relation to aortic pathology.

METHODS

A magnetic-resonance-imaging (MRI) study of the thoracic aorta and of the lumbosacral spine was done in an inclusive series of 83 patients with Marfan's syndrome to assess the presence and degree of dural ectasia and aortic involvement; 12 patients were younger than 18 years. 100 individuals who underwent MRI of the lumbar spine for routine clinical indications represented the control group; none of them had any potential causes for dural ectasia.

FINDINGS

Dural ectasia was identified in 76 (92%) patients and none of the control group. The severity of dural ectasia was related to age; the mean (SD) age of patients with mild dural ectasia was 26 years (14) whereas that of those with severe disease (meningocele) was 36 years (9) (p=0.038). 11 of 12 patients younger than 18 years had dural ectasia. No association was found between aortic dilatation and dural ectasia.

INTERPRETATION

Dural ectasia is a highly characteristic sign of Marfan's syndrome, even at an early age.