Color flow and conventional echocardiography of the Marfan syndrome

Marfan syndrome: current perspectives

Marfan syndrome (MFS) is a pleiotropic connective tissue disease inherited as an autosomal dominant trait, due to mutations in the FBN1 gene encoding fibrillin 1. It is an important protein of the extracellular matrix that contributes to the final structure of a microfibril. Few cases displaying an autosomal recessive transmission are reported in the world. The FBN1 gene, which is made of 66 exons, is located on chromosome 15q21.1. This review, after an introduction on the clinical manifestations that leads to the diagnosis of MFS, focuses on cardiovascular manifestations, pharmacological and surgical therapies of thoracic aortic aneurysm and/or dissection (TAAD), mechanisms underlying the progression of aneurysm or of acute dissection, and biomarkers associated with progression of TAADs. A Dutch group compared treatment with losartan, an angiotensin II receptor-1 blocker, vs no other additional treatment (COMPARE clinical trial). They observed that losartan reduces the aortic dilatation rate in patients with Marfan syndrome. Later on, they also reported that losartan exerts a beneficial effect on patients with Marfan syndrome carrying an FBN1 mutation that causes haploinsufficiency (quantitative mutation), while it has no significant effect on patients displaying dominant negative (qualitative) mutations. Moreover, a French group in a 3-year trial compared the administration of losartan vs placebo in patients with Marfan syndrome under treatment with beta-receptor blockers. They observed that losartan decreases blood pressure but has no effect on aortic diameter progression. Thus, beta-receptor blockers remain the gold standard therapy in patients with Marfan syndrome. Three potential biochemical markers are mentioned in this review: total homocysteine, serum transforming growth factor beta, and lysyl oxidase. Moreover, markers of oxidative stress measured in plasma, previously correlated with clinical features of Marfan syndrome, may be explored as potential biomarkers of clinical severity.

Cardiovascular manifestations in Marfan syndrome and related diseases; multiple genes causing similar phenotypes

Cardiovascular abnormalities are the major cause of morbidity and mortality in Marfan syndrome (MFS) and a few clinically related diseases that share, with MFS, the pathogenic contribution of dysregulated transforming growth factor β (TGFβ) signaling. They include Loeys-Dietz syndrome, Shprintzen-Goldberg syndrome, aneurysm-osteoarthritis syndrome and syndromic thoracic aortic aneurysms. Unlike the causal association of MFS with mutations in an extracellular matrix protein (ECM), the aforementioned conditions are due to defects in components of the TGFβ pathway. While TGFβ antagonism is being considered as a potential new therapy for these heritable syndromes, several points still need to be clarified in relevant animal models before this strategy could be safely applied to patients. Among others, unresolved issues include whether elevated TGFβ signaling is responsible for all MFS manifestations and is the common trigger of disease in MFS and related conditions. The scope of our review is to highlight the clinical and experimental findings that have forged our understanding of the natural history and molecular pathogenesis of cardiovascular manifestations in this group of syndromic conditions.

The economic impact of Marfan syndrome: a non-experimental, retrospective, population-based matched cohort study

Background

Marfan syndrome is a rare disease of the connective tissues, affecting multiple organ systems. Elevated morbidity and mortality in these patients raises the issue of costs for sickness funds and society. To date, there has been no study analysing the costs of Marfan syndrome from a sickness fund and societal perspective.

Objective

To estimate excess health resource utilisation, direct (non-)medical and indirect costs attributable to Marfan syndrome from a healthcare payer and a societal perspective in Germany in 2008.

Methods

A retrospective matched cohort study design is applied, using claims data. For isolating the causal effect of Marfan syndrome on excess costs, a genetic matching algorithm was used to reduce differences in observable characteristics between Marfan syndrome patients and the control group. 892 patients diagnosed with Marfan syndrome (ICD-10 Q87.4) were matched from a pool of 26,645 control individuals. After matching, we compared health resource utilisation and costs.

Results

From the sickness fund perspective, an average Marfan syndrome patient generates excess annual costs of €2496 compared with a control individual. From the societal perspective, excess annual costs amount to €15,728. For the sickness fund, the strongest cost drivers are inpatient treatment and care by non-physicians. From the sickness fund perspective, the third (25–41 years) and first (0–16 years) age quartiles reveal the greatest surplus in total costs. Marfan syndrome patients have 39% more physician contacts, a 153% longer average length of hospital stay, 119% more inpatient stays, 33% more prescriptions, 236% more medical imaging and 20% higher average prescription costs than control individuals. Depending on the prevalence, the economic impact from the sickness fund perspective ranges between €24.0 million and €61.4 million, whereas the societal economic impact extends from €151.3 million to €386.9 million.

Conclusions

Relative to its low frequency, Marfan syndrome requires high healthcare expenditure. Not only the high costs of Marfan syndrome but also its burden on patients’ lives call for more awareness from policy-makers, physicians and clinical researchers. Consequently, the diagnosis and treatment of Marfan syndrome should begin as soon as possible in order to prevent disease complications, early mortality and substantial healthcare expenditure.

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.

Association between psychiatric disorders and Marfan's syndrome in a large Sardinian family with a high prevalence of cardiac abnormalities

BACKGROUND

Marfan's syndrome is an inherited disorder of connective tissue associated with characteristic abnormalities of the skeletal, ocular, and cardiovascular systems. Marked clinical variability and age dependency of all manifestations of Marfan's syndrome may render the unequivocal diagnosis difficult in mildly affected, young subjects.

HYPOTHESIS

The study and care of a 32-year-old woman with evidence of Marfan's syndrome, several cardiac abnormalities, and paranoid schizophrenia led to an investigation of her consenting relatives to verify the penetrance of Marfan's syndrome and the degree of comorbidity between the disease and psychiatric disorders.

METHODS

The patient and 12 subjects belonging to three generations of her family underwent cardiovascular, skeletal, ophthalmologic, and psychiatric examinations. Two-dimensional and Doppler echocardiography were performed.

RESULTS

One female index patient and six of her first-degree relatives were found to be affected by Marfan's syndrome. All seven patients were found to have mitral valve prolapse associated with other cardiac abnormalities. Four of these patients were affected by the following psychiatric disorders: generalized anxiety disorder, major depressive disorder, paranoid schizophrenia (two cases). Six more relatives without Marfan's syndrome showed mitral valve prolapse in association with other echocardiographic features. Two of these were found to be affected by a major depressive disorder.

CONCLUSIONS

The present data support the hypothesis that a psychiatric condition, associated with a significantly high frequency of cardiac involvement, may be part of the phenotype of Marfan's syndrome.

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

BACKGROUND

Patients with Marfan syndrome may develop aortic root dissection despite only mild aortic root dilation as shown by standard echocardiography, which may be due to aortic root asymmetry. Purpose of the present study was to investigate aortic root asymmetry by magnetic resonance (MR) imaging in patients with Marfan syndrome and to compare these measurements with standardly performed echocardiography.

METHODS

Eighty-seven Marfan patients (mean age 31 +/- 8 years) underwent MR imaging. From this population, 15 patients (mean age 29 +/- 3 years) were selected in whom both echocardiography and MR imaging had been performed within 3 months. With echocardiography, the aortic root was measured according to the recommendations of the American Society of Echocardiography. With MR imaging, a short axis view of the aortic root was obtained to measure distances between the noncoronary, right coronary and left coronary cusps and the aortic root area. Correlations between aortic root area and diameters were assessed, and 95% confidence intervals (95% CIs) calculated.

RESULTS

No difference in the standardly measured noncoronary to right coronary cusp diameter between MR imaging and echocardiography was shown (42 +/- 6 mm). Largest aortic root diameter on the MR images was the right to left coronary cusp diameter (46 +/- 7 mm, p < 0.02). For a given noncoronary to right coronary cusp diameter, 95% confidence intervals revealed a variation of -20 to +20% in the aortic root area.

CONCLUSIONS

The majority of Marfan patients show asymmetric dilation of the aortic root by MR imaging. This phenomenon may go unnoticed when standard echocardiography is performed. The asymmetry of the aortic root might be of clinical importance in unexpected aortic root dissection.

Aneurysms in the left ventricular outflow tract: clinical presentation, causes, and echocardiographic features

We present a descriptive compendium of anatomically interrelated aneurysms and aneurysmal-like structures arising in and around the left ventricular outflow tract. Images selected from the Mayo Clinic echocardiography database illustrate classic or typical examples of each entity. Essential morphologic features of each lesion are described. Clinical presentation, causes, and diagnostic echocardiographic features taken together can improve recognition and clinical management of this diverse group of anomalies.

Role of echocardiography in perioperative management of patients undergoing open heart surgery

TEE has assumed a pivotal role in the perioperative management of patients undergoing open-heart surgery. The information obtained influences important therapeutic decisions in thoracic aortic surgery, valvular surgery, and coronary artery bypass surgery. TEE also assists in determining the reason for failure to wean from cardiopulmonary bypass and allows rapid detection of the etiology of hypotension in the patient after surgery. Advances in technology have resulted in three-dimensional images of cardiac structures, and this will further enhance the usefulness of echocardiography for the surgeon. TEE should no longer be regarded as an imaging tool available only in academic centers, but should be routinely used by qualified operators in centers performing open-heart surgery.