Aortic root asymmetry in marfan patients; evaluation by magnetic resonance imaging and comparison with standard echocardiography

Management of aortic disease in children with FBN1-related Marfan syndrome

Marfan syndrome (MFS) is a hereditary connective tissue disorder with an estimated prevalence of 1:5000-1:10 000 individuals. It is a pleiotropic disease characterized by specific ocular, cardiovascular, and skeletal features. The most common cardiovascular complication is aortic root dilatation which untreated can lead to life-threatening aortic root dissection, mainly occurring in adult patients. Prompt diagnosis, appropriate follow-up, and timely treatment can prevent aortic events. Currently there are no specific recommendations for treatment of children with MFS, and management is greatly based on adult guidelines. Furthermore, due to the scarcity of studies including children, there is a lack of uniform treatment across different centres. This consensus document aims at bridging these gaps of knowledge. This work is a joint collaboration between the paediatric subgroup of the European Network of Vascular Diseases (VASCERN, Heritable Thoracic Aortic Disease Working Group) and the Association for European Paediatric and Congenital Cardiology (AEPC). A group of experts from 12 different centres and 8 different countries participated in this effort. This document reviews four main subjects, namely, (i) imaging of the aorta at diagnosis and follow-up, (ii) recommendations on medical treatment, (iii) recommendations on surgical treatment, and (iv) recommendations on sport participation.

Marfan Syndrome beyond Aortic Root-Phenotyping Using Cardiovascular Magnetic Resonance Imaging and Clinical Implications

Marfan syndrome (MFS) is an inherited autosomal-dominant connective tissue disorder with multiorgan involvement including musculoskeletal, respiratory, cardiovascular, ocular, and skin manifestations. Life expectancy in patients with MFS is primarily determined by the degree of cardiovascular involvement. Aortic disease is the major cardiovascular manifestation of MFS. However, non-aortic cardiac diseases, such as impaired myocardial function and arrhythmia, have been increasingly acknowledged as additional causes of morbidity and mortality. We present two cases demonstrating the phenotypical variation in patients with MFS and how CMR (Cardiovascular Magnetic Resonance) could serve as a "one stop shop" to retrieveS all the necessary information regarding aortic/vascular pathology as well as any potential underlying arrhythmogenic substrate or cardiomyopathic process.

Magnetic resonance angiography derived predictors of progressive dilatation and surgery of the aortic root in Marfan syndrome

BACKGROUND

To identify magnetic resonance (MR) angiography derived predictors of progressive dilatation and surgery of the aortic root in Marfan syndrome.

MATERIAL AND METHODS

We retrospectively included 111 patients (32.7±16.5 years, range: 7-75 years) with a total of 446 MR angiographies. Aortic diameter growth rates of the entire thoracic aorta and Z-scores were estimated from annual diameter measurements. Aortic root shape was subdivided into three different types: (T0) normal; (T1) localized dilatation; (T2) generalized aortic root dilatation. Aortic diameter, Z-score, age, and aortic root shape at baseline were tested as predictors of aortic root dilatation using a multivariate logistic regression model.

RESULTS

The highest aortic growth rate was observed at the level of the sinuses of Valsalva. Higher aortic root diameters and Z-scores at baseline predicted an increased growth of the aortic root (p = 0.003 and p<0.001). Young age (<30 years) was a predictor for the increase of Z-scores when compared to patients ≥30 years (p = 0.019). 25/111 patients (22.5%) had a T0 aortic root shape, 59/111 patients (53.2%) had a T1 aortic root shape, and 27/111 patients (24.3%) had a T2 aortic root shape. Aortic root shape did not predict further aortic growth (p>0.05). However, significantly more patients undergoing surgery had a generalized aortic dilatation (19/28, 76.9%) than a localized aortic root dilatation (9/28, 32.1%) (p = 0.001).

CONCLUSION

Larger baseline aortic root diameter and Z-score as well as young age predict solely progressive aortic root dilatation in Marfan patients. MR angiography derived type of aortic root shape does not predict aortic growth, but patients with generalized aortic root dilatation are referred more frequently for aortic surgery.

No beneficial effect of general and specific anti-inflammatory therapies on aortic dilatation in Marfan mice

Aims

Patients with Marfan syndrome have an increased risk of life-threatening aortic complications, mostly preceded by aortic dilatation. In the FBN1^C1039G/+ Marfan mouse model, losartan decreases aortic root dilatation. We recently confirmed this beneficial effect of losartan in adult patients with Marfan syndrome. The straightforward translation of this mouse model to man is reassuring to test novel treatment strategies. A number of studies have shown signs of inflammation in aortic tissue of Marfan patients. This study examined the efficacy of anti-inflammatory therapies in attenuating aortic root dilation in Marfan syndrome and compared effects to the main preventative agent, losartan.

Methods and Results

To inhibit inflammation in FBN1^C1039G/+ Marfan mice, we treated the mice with losartan (angiotensin II receptor type 1 inhibitor), methylprednisolone (corticosteroid) or abatacept (T-cell-specific inhibitor). Treatment was initiated in adult Marfan mice with already existing aortic root dilatation, and applied for eight weeks. Methylprednisolone- or abatacept-treated mice did not reveal a reduction in aortic root dilatation. In this short time frame, losartan was the only treatment that significantly reduced aorta inflammation, transforming growth factor-beta (TGF-β) signaling and aortic root dilatation rate in these adult Marfan mice. Moreover, the methylprednisolone-treated mice had significantly more aortic alcian blue staining as a marker for aortic damage.

Conclusion

Anti-inflammatory agents do not reduce the aortic dilatation rate in Marfan mice, but possibly increase aortic damage. Currently, the most promising therapeutic drug in Marfan syndrome is losartan, by blocking the angiotensin II receptor type 1 and thereby inhibiting pSmad2 signaling.

Pregnancy outcomes among women with Marfan syndrome

OBJECTIVE

To determine cardiac and obstetric outcomes among women with Marfan syndrome (MS) whose pregnancies were managed in accordance with the French national guidelines.

METHODS

A descriptive analysis was conducted for a prospective cohort of 18 women with MS who gave birth in the maternity unit of Bichat-Claude Bernard Hospital, Paris, France, between January 1, 1998, and May 31, 2011. The study hospital was the national referral center for MS and related diseases.

RESULTS

A total of 22 pregnancies were recorded among the study cohort. Of these, 21 were managed according to the national guidelines. One woman who was referred to the study hospital during late pregnancy was not managed according to the national guidelines; this patient experienced aortic dissection at 37 weeks. In the cohort, aortic diameter did not increase significantly during pregnancy. Vascular fetal growth restriction was observed in 7 (31.8 %) of the pregnancies. Cesarean delivery was planned for 17 (77.3%) of the pregnancies.

CONCLUSION

Risk of aortic dissection was low among a cohort of pregnant women with MS who were managed according to the French national guidelines.

Cardiovascular magnetic resonance in Marfan syndrome

This review provides an overview of Marfan syndrome with an emphasis on cardiovascular complications and cardiovascular imaging. Both pre- and post-operative imaging is addressed with an explanation of surgical management. All relevant imaging modalities are discussed with a particular focus on cardiovascular MR.

Circulating transforming growth factor-β as a prognostic biomarker in Marfan syndrome

BACKGROUND

Patients with Marfan syndrome (MFS) are at risk for cardiovascular disease. Marfan associated mutations in the FBN1 gene lead to increased transforming growth factor-β (TGF-β) activation. The aim of this study was to investigate the role of plasma TGF-β as a biomarker for progressive aortic root dilatation and dissection.

METHODS

Plasma TGF-β level and aortic root diameter by means of echocardiography were assessed in 99 MFS patients. After 38 months of follow-up measurement of the aortic root was repeated and individual aortic root growth curves were constructed. Clinical events were evaluated. The primary composite endpoint was defined as aortic dissection and prophylactic aortic root replacement.

RESULTS

TGF-β levels were higher in MFS patients as compared to healthy controls (109 pg/ml versus 54 pg/ml, p<0.001). Higher plasma TGF-β levels correlated with larger aortic root dimensions (r=0.26, p=0.027), previous aortic root surgery (161 pg/ml versus 88 pg/ml, p=0.007) and faster aortic root growth rate (r=0.42, p<0.001). During 38 months of follow-up, 17 events were observed (four type B dissections and 13 aortic root replacements). Patients with TGF-β levels above 140 pg/ml had a 6.5 times higher risk of experiencing the composite endpoint compared to patients with TGF-β levels below 140 pg/ml (95% CI: 2.1 to 20.1, p=0.001) with 65% sensitivity and 78% specificity.

CONCLUSION

Elevated TGF-β level in patients with Marfan syndrome is correlated with larger aortic root diameters and faster aortic root growth. Level of plasma TGF-β predicts cardiovascular events and might serve as a prognostic biomarker in MFS.

Impact of image analysis methodology on diagnostic and surgical classification of patients with thoracic aortic aneurysms

BACKGROUND

For patients with thoracic aortic aneurysms (TAA), aortic size on imaging is widely used to guide clinical decision making. This study examined the impact of methodological variance on aortic quantification.

METHODS

We studied enrollees in the National Registry of Genetically Triggered Thoracic Aortic Aneurysms and Cardiovascular Conditions. Aortic size on computed tomography was quantified by 2 linear methods; cross-sectional dimensions in axial (AX) and double oblique (DO) plane. Calculated area was compared to planimetry. Established cutoffs (area/height>10 cm2/m, diameter≥5 cm) for prophylactic TAA repair were used to compare surgical eligibility by each method.

RESULTS

Fifty subjects were studied. Aortic size differed between AX and DO at all locations (p≤0.001), with magnitude greatest at the sinotubular junction (4.8±1.1 vs 4.0±1.0 cm, p<0.001). The difference between AX and DO correlated with aortic angular displacement (r=0.37, p<0.01), which was threefold larger at the sinotubular junction (37±12 degrees) than the ascending aorta (12±5 degrees; p<0.001). At all locations, aortic area calculated using DO yielded smaller differences with planimetry than AX (p<0.05). DO and planimetry yielded equal prevalence (24%) of subjects eligible for prophylactic TAA repair based on area-height cutoff, whereas AX prevalence was higher (44%; p=0.006). Using a linear cutoff, AX yielded over a twofold greater prevalence of surgically eligible subjects (56%) than did DO (24%; p<0.001).

CONCLUSIONS

Established linear methods for aortic measurement yield different results that impact surgical eligibility. DO yielded improved agreement with planimetry and differed with AX in proportion to aortic geometric obliquity. Findings support DO measurements for imaging evaluation of subjects with TAA.

Quantitative assessment of the entire thoracic aorta from magnetic resonance images

OBJECTIVES

Although magnetic resonance imaging is a primary modality for following patients with connective tissue diseases, only a limited amount of the image data is utilised. The purpose of this study was to show the clinical applicability of an automated four-dimensional analysis method of magnetic resonance images of the aorta and develop normative data for the cross-sectional area of the entire thoracic aorta.

STUDY DESIGN

Magnetic resonance imaging was obtained serially over 3 years from 32 healthy individuals and 24 patients with aortopathy and a personal or family history of connective tissue disorder. Graph theory-based segmentation was used to determine the cross-sectional area for the thoracic aorta. Healthy individual data were used to construct a nomogram representing the maximum cross-sectional area 5th-95th percentile along the entire thoracic aorta. Aortic root diameters calculated from the cross-sectional area were compared to measured diameters from echocardiographic data. The cross-sectional area of the entire thoracic aorta in patients was compared to healthy individuals.

RESULTS

Calculated aortic root diameters correlated with measured diameters from echo data - correlation coefficient was 0.74-0.87. The cross-sectional area in patients was significantly greater in the aortic root, ascending aorta, and descending aorta compared to healthy individuals.

CONCLUSION

The presentation of the dimensional data for the entire thoracic aorta shows an important clinical tool for following patients with connective tissue disorders and aortopathy.

Critical appraisal of the revised Ghent criteria for diagnosis of Marfan syndrome

Marfan syndrome (MFS) is a connective tissue disorder with major features in cardiovascular, ocular and skeletal systems. Recently, diagnostic criteria were revised where more weight was given to the aortic root dilatation. We applied the revised Marfan nosology in an established adult Marfan population to define practical repercussions of novel criteria for clinical practice and individual patients. Out of 180 MFS patients, in 91% (n = 164) the diagnosis of MFS remained. Out of 16 patients with rejected diagnosis, four patients were diagnosed as MASS (myopia, mitral valve prolapse, borderline non-progressive aortic root dilatation, skeletal findings and striae) phenotype, three as ectopia lentis syndrome and in nine patients no alternative diagnosis was established. In 13 patients, the diagnosis was rejected because the Z-score of the aortic root was <2, although the aortic diameter was larger than 40 mm in six of them. In three other patients, the diagnosis of MFS was rejected because dural ectasia was given less weight in the revised nosology. Following the revised Marfan nosology, the diagnosis of MFS was rejected in 9% of patients, mostly because of the absence of aortic root dilatation defined as Z-score ≥2. Currently used Z-scores seem to underestimate aortic root dilatation, especially in patients with large body surface area (BSA). We recommend re-evaluation of criteria for aortic root involvement in adult patients with a suspected diagnosis of MFS.

Marfan's syndrome: an overview

Marfan's syndrome is an autosomal dominant condition with an estimated prevalence of one in 10,000 to 20,000 individuals. This rare hereditary connective tissue disorder affects many parts of the body. The diagnosis of Marfan's syndrome is established in accordance with a review of the diagnostic criteria, known as the Ghent nosology, through a comprehensive assessment largely based on a combination of major and minor clinical manifestations in various organ systems and the family history. Aortic root dilation and mitral valve prolapse are the main presentations among the cardiovascular malformations of Marfan's syndrome. The pathogenesis of Marfan's syndrome has not been fully elucidated. However, fibrillin-1 gene mutations are believed to exert a dominant negative effect. Therefore, Marfan's syndrome is termed a fibrillinopathy, along with other connective tissue disorders with subtle differences in clinical manifestations. The treatment may include prophylactic β-blockers and angiotensin II-receptor blockers in order to slow down the dilation of the ascending aorta, and prophylactic aortic surgery. Importantly, β-blocker therapy may reduce TGF-β activation, which has been recognized as a contributory factor in Marfan's syndrome. The present article aims to provide an overview of this rare hereditary disorder.

Cardiovascular manifestations in men and women carrying a FBN1 mutation

AIMS

In patients with Marfan syndrome and other type-1 fibrillinopathies, genetic testing is becoming more easily available, leading to the identification of mutations early in the course of the disease. This study evaluates the cardiovascular (CV) risk associated with the discovery of a fibrillin-1 (FBN1) mutation.

METHODS AND RESULTS

A total of 1,013 probands with pathogenic FBN1 mutations were included, among whom 965 patients [median age: 22 years (11-34), male gender 53%] had data suitable for analysis. The percentage of patients with an ascending aortic (AA) dilatation increased steadily with increasing age and reached 96% (95% CI: 94-97%) by 60 years. The presence of aortic events (dissection or prophylactic surgery) was rare before 20 years and then increased progressively, reaching 74% (95% CI: 67-81%) by 60 years. Compared with women, men were at higher risk for AA dilatation [≤ 30 years: 57% (95% CI: 52-63) vs. 50% (95% CI: 45-55), P = 0.0076] and aortic events [≤ 30 years: 21% (95% CI: 17-26) vs. 11% (95% CI: 8-16), P < 0.0001; adjusted HR: 1.4 (1.1-1.8), P = 0.005]. The prevalence of mitral valve (MV) prolapse [≤ 60 years: 77% (95% CI: 72-82)] and MV regurgitation [≤ 60 years: 61% (95% CI: 53-69)] also increased steadily with age, but surgery limited to the MV remained rare [≤ 60 years: 13% (95% CI: 8-21)]. No difference between genders was observed (for all P> 0.20). From 1985 to 2005 the prevalence of AA dilatation remained stable (P for trend = 0.88), whereas the percentage of patients with AA dissection significantly decreased (P for trend = 0.01).

CONCLUSION

The CV risk remains important in patients with an FBN1 gene mutation and is present throughout life, justifying regular aortic monitoring. Aortic dilatation or dissection should always trigger suspicion of a genetic background leading to thorough examination for extra-aortic features and comprehensive pedigree investigation.

Automated analysis of four-dimensional magnetic resonance images of the human aorta

The purpose of the study was to demonstrate the accuracy and clinical utility of an automated method of image analysis of 4D (3D + time) magnetic resonance (MR) imaging of the human aorta. Serial MR images of the entire thoracic aorta were acquired on 32 healthy individuals. Graph theory based segmentation was applied to the images and cross sectional area (CSA) was determined for the entire length of thoracic aorta. Mean CSA was compared between the 3 years. CSA values at the level of sinuses of Valsalva and sino-tubular junction were used to calculate average diameters for comparison to Roman-Devereux norms. A robust automated segmentation method was developed that accurately reproduced CSA measurements for the entire length of thoracic aorta in serially acquired scans with a 1% error compared to expert tracing. Calculated aortic root diameters based on CSA correlated with Roman-Devereux norms. Mean CSA for the aortic root agreed well with previously published manually derived values. Automated analysis of 4D MR images of the thoracic aorta provides accurate and reproducible results for CSA in healthy human subjects. The ability to simultaneously analyze the entire length of thoracic aorta throughout the cardiac cycle opens the door to the calculation of novel indices of aortic biophysical properties. These novel indices may lead to earlier detection of patients at risk for adverse events.

The distal aorta in the Marfan syndrome

Prolonged survival of patients with Marfan syndrome after aortic root replacement has led to an increased number of patients with aortic complications beyond the root. Elective replacement of the aortic root removes the most important predilection site for aneurysms, but the distal aorta remains at risk. Predictors for aortic growth and adverse events in the distal aorta include aortic diameter, aortic distensiblity, previous aortic root replacement, hypertension and aortic regurgitation. After aortic dissection, the initial false lumen diameter is an independent predictor for late aneurysm formation. Although there are a few reports of short-term success after endovascular stent grafting of the descending thoracic aorta, stent grafting in patients with Marfan syndrome is not recommended unless intervention is clearly indicated and the risk of conventional open surgical repair is deemed prohibitive. Optimal long-term outcome demands lifelong radiographic follow-up and medical treatment with beta-blocker therapy. After aortic dissection rigorous antihypertensive medication is of utmost importance. Losartan, an angiotensin II type I receptor antagonist, might offer the first potential for primary prevention of clinical manifestations in Marfan syndrome, but the results of clinical trials have to be awaited. (Neth Heart J 2008;16:382-6.).

A critical analysis of minor cardiovascular criteria in the diagnostic evaluation of patients with Marfan syndrome

PURPOSE

The prevalence of most minor cardiovascular manifestations in Marfan syndrome (MFS) is unknown. We assessed the prevalence of minor cardiovascular manifestations in MFS to evaluate their usefulness in a diagnostic setting.

METHODS

Seventy-seven patients with MFS (aged 4 months to 55 years) underwent echocardiography to assess the presence of mitral valve prolapse and the diameter of the main pulmonary artery. A subset of 29 adult patients with MFS also underwent magnetic resonance imaging evaluation of the diameters of the thoracoabdominal aorta.

RESULTS

Mitral valve prolapse was encountered in 66% of patients with MFS, with an equal distribution of classic and nonclassic mitral valve prolapse. The main pulmonary artery diameter was significantly larger in patients with MFS at all ages when compared with controls. In the adult group (> or = 14 years), we were able to provide a cutoff value of 23 mm to define pulmonary artery dilatation. The descending aorta was enlarged, but with substantial overlap with controls, thus precluding the use of a cutoff value.

CONCLUSIONS

Mitral valve prolapse and main pulmonary artery dilatation are common findings in MFS patients at all ages and are easy to assess with echocardiography. Cutoff values to define dilatation of the descending aorta are hard to define, making them of limited value in the diagnostic evaluation. We recommend echocardiographic evaluation of mitral valve prolapse and main pulmonary artery diameter in patients referred for cardiovascular diagnostic assessment for MFS.

Cardiovascular magnetic resonance in the follow-up of patients with corrected tetralogy of Fallot: a review

Cardiovascular magnetic resonance (CMR) is becoming an important tool in the clinical management of patients with congenital heart disease. Because of the diverse problems patients may face after initial correction for tetralogy of Fallot and the large amount of CMR techniques that can be applied, creating a patient-orientated imaging protocol is a difficult issue. Although it is still not certain what the impact of some parameters, provided by CMR, should be on clinical decision making, new techniques are being developed and applied. In this report, we review the current clinical issues in patients with tetralogy of Fallot and review the current implication and limitations of CMR in this patient category.

[Three-dimensional echocardiography in congenital heart disease]

The introduction of real time three-dimensional (3D) echocardiography has led to its use in everyday clinical practice. The 3D matrix probe enables the instantaneous acquisition of transthoracic volumes. Several modes of 3D are available: 3D volume, biplan and 3D color Doppler. Real time 3D echocardiography gave more accurate description of various congenital heart diseases as well as valvulopathy, shunt and aorta pathology. Fetal 3D echocardiography is available. Quantitative measurement of ventricular volumes could be obtain by 3D echocardiography. The facility of utilisation of the matrix probe should lead to routine usage of 3D echocardiography as with 2D and Doppler method. Its values should be decisive in many congenital cardiac lesions requiring surgery or interventional catheterisation.

Aortic root growth in men and women with the Marfan's syndrome

The leading cause of premature death in patients with Marfan's syndrome (MS) is type A aortic dissection or rupture due to progressive aortic root dilation. The aim of this study was to analyze aortic root growth in 113 men and 108 women with MS. All patients were prospectively followed with serial echocardiograms of the native aortic root. At baseline, women had on average a 5-mm smaller aortic root diameter adjusted for age than men. Average aortic root growth was 0.42 mm/year (SE 0.05) in men and 0.38 mm/year (SE 0.04) in women. On the basis of aortic root growth rates, the men and women could be divided into 2 normally distributed subgroups: fast and slow growers. Approximately 1 in 7 men (1.5 mm/year, SE 0.5) and approximately 1 in 9 women (1.8 mm/year, SE 0.3) had fast-growing aortic root diameters. Significantly more type A dissections (25% vs 4%, p <0.001) were observed in fast growers than in slow growers; this was found in men and women. Type A dissections were observed in 4 men and 9 women. By reducing the cut-off value by 5 mm for elective aortic root replacement in women, type A dissections could have been prevented in 3 women. In conclusion, guidelines should take gender differences into account, and therefore, the investigators propose reducing the threshold for elective aortic root replacement in women with MS by 5 mm.

Pregnancy and aortic root growth in the Marfan syndrome: a prospective study

AIMS

In women with Marfan syndrome pregnancy presents an increased risk of dilatation, dissection, and rupture of the aorta. The aim of this study was to investigate the influence of pregnancy on growth of the aortic root.

METHODS AND RESULTS

Between 1993 and 2004 127 women with Marfan syndrome were prospectively followed; 61 women had one or more children; in 23 women, 33 pregnancies could be followed prospectively for aortic dimensions. Only one woman had suffered an aortic complication, a type A dissection (limited to the ascending aorta), before pregnancy. Out of 66 childless women a comparison group of 22 women was selected and individually matched. Mean initial aortic root diameter just before pregnancy was 37+/-5 mm (range 25-45). Before, during, and after pregnancy the overall individual aortic root diameter change (in 31 pregnancies) was not significant (P=0.77). Only the woman with a previous type A dissection developed an aortic complication (type B dissection) during her second pregnancy. No cardiac complications occurred in the other 22 women during their pregnancies. During a median follow-up of 6.4 years, no significant difference in growth of the aortic root was observed between the pregnancy group and the matched childless group (0.28 vs. 0.19 mm/year, P=0.08, respectively).

CONCLUSION

Pregnancy in women with Marfan syndrome seems to be relatively safe up to an aortic root diameter of 45 mm, at least as far as our observed diameter range of 25-45 mm is concerned.

What is new in the Marfan syndrome?

The Marfan syndrome is an autosomal dominant disorder of connective tissue, caused by mutations in the FBN1 gene on chromosome 15. More than 500 mutations have been identified and almost all are unique to an affected individual or family. Genotype--phenotype correlations in the Marfan syndrome have been complicated by the large number of unique mutations reported, as well as by clinical heterogeneity among individuals with the same mutation. A relatively unknown cardiovascular manifestation of Marfan syndrome is dilatation of the main pulmonary artery. Of 50 patients with Marfan syndrome, MR imaging showed in 74% patients an enlarged pulmonary artery root above the upper limit of normal. Aortic elasticity determined by measurement of local distensibility and flow wave velocity with MR imaging is decreased in non-operated patients with Marfan syndrome. Aortic distensibility of the thoracic descending aorta appeared to be the strongest predictor for descending aortic complications. Over the past 30 years improvement of diagnostic modalities and aggressive medical and surgical therapy, have resulted in considerable improvement of life expectancy of patients with Marfan syndrome. Further studies are needed to investigate the role of modulating genes and genotype--phenotype correlations. Long-term follow-up studies may reveal the prognostic significance of aortic elasticity and may identify patients at risk of aortic complications.

Role of MRI in clinical cardiology

Rapid progress has been made in cardiac MRI (CMRI) over the past decade, which has firmly established it as a reliable and clinically important technique for assessment of cardiac structure, function, perfusion, and myocardial viability. Its versatility and accuracy is unmatched by any other individual imaging modality. CMRI is non-invasive and has high spatial resolution and avoids use of potentially nephrotoxic contrast agent or radiation. It has been extensively studied against other established non-invasive imaging modalities and has been shown to be superior in many scenarios, particularly with respect to assessment of cardiac and great vessel morphology and left ventricular function. Furthermore, its clinical use continues to expand with increasing experience and proliferation of CMRI centres. As worldwide prevalence of cardiovascular disease continues to rise, CMRI provides opportunity for improved and cost-effective non-invasive assessment. Continued progress in CMRI technology promises to further widen its clinical application in coronary imaging, myocardial perfusion, comprehensive assessment of valves, and plaque characterisation.

Magnetic resonance imaging of the main pulmonary artery: reliable assessment of dimensions in Marfan patients on a simple axial spin echo image

OBJECTIVE

To investigate if a simple axial spin echo (SE) image can be used for reliable assessment of pulmonary artery dimensions in patients with Marfan syndrome.

METHODS

Fifty Marfan patients (mean age 33 +/- 10 years; 34 men, 16 women) and 15 normal subjects (mean age 28 +/- 4 years; nine men, six women) underwent cardiac magnetic resonance imaging (MRI). Pulmonary artery dimensions were obtained on axial SE images at two different levels: (1) the level of the pulmonary artery root, and (2) the level of the pulmonary artery bifurcation. To evaluate the accuracy of axial plane measurements 10 Marfan patients also underwent contrast-enhanced MR angiography (CE-MRA).

RESULTS

In the 10 Marfan patients who also underwent CE-MRA, the mean diameter at the pulmonary bifurcation assessed with CE-MRA (31.5 +/- 3.6 mm) was almost equal to mean diameter assessed with axial SE (30.7 +/- 3.6 mm). Agreement of methodology according to Bland and Altman analysis showed a 95% confidence interval ranging from -2.6 to + 4.4 mm for all distances of the pulmonary artery root. In Marfan patients the mean right-left diameter measured on both axial SE images and CE-MRA was approximately 2.5 mm larger than the anterior-right and anterior-left diameters (p < 0.001).

CONCLUSIONS

Axial SE MRI is a reliable and easy acquisition to measure pulmonary artery dimensions in patients with Marfan syndrome, and could be used for follow-up, especially in patients with severe involvement of the cardiovascular system. Not only the pulmonary artery trunk but also the asymmetric pulmonary root should be measured, although the clinical relevance of the asymmetric root is not yet known.

Magnetic resonance microscopy quantifies the disease progression in Marfan syndrome mice

PURPOSE

To use noninvasive magnetic resonance microscopy (MRM) to examine aneurysmal disease in the mouse model of Marfan syndrome (MFS).

MATERIALS AND METHODS

A total of eight wild-type (WT) and MFS mice were imaged using MRM; four of them at three different time points over an 8-week period and the remaining animals were imaged at one time point. The maximal cross-sectional area of the aorta was measured by manual tracing and by automated means from combined cardiac and respiratory-gated bright-blood images. Relationships between aortic size and age and the differences between WT and mutant mice aortic size were established.

RESULTS

Maximal cross-sectional aortic areas differed significantly (P < 0.05) between WT and mutant mice for all time points, with MFS mice having larger aortic size. There was a positive correlation between aortic size and age in MFS mice (r = 0.80) with a significant increase from the 14th to the 22nd week (P < 0.05).

CONCLUSION

MRM detected the differences in aortic size between WT and mutant mice over time, demonstrating a potential for noninvasive technique for the assessment of potential therapies in MFS mice.

Current insights in diagnosis and management of the cardiovascular complications of Marfan's syndrome

Marfan's syndrome is an inherited disorder of connective tissue, caused by mutations in the fibrillin-1 gene located on chromosome 15. Diagnosis is still based on a combination of major and minor clinical features. Prognosis is mainly determined by the cardiovascular complications. Advances in surgical and medical treatment for these complications have dramatically improved the prognosis of the syndrome.