FBN1 gene mutation characteristics and clinical features for the prediction of mitral valve disease progression.

BACKGROUND: Until today, FBN1 gene mutation characteristics were not compared with clinical features for the prediction of mitral valve disease progression. METHODS: Therefore, we conducted a study of 116 patients (53 men, 63 women aged 33 ± 15 years) with a causative FBN1 gene mutation and ≤ moderate mitral valve regurgitation at baseline. RESULTS: During 7.4 ± 6.8 years 30 patients developed progression of mitral valve regurgitation ≥ 1 grade (primary endpoint), and 26 patients required mitral valve surgery (secondary endpoint). Cox regression analysis identified an association of atrial fibrillation (hazard ratio (HR)=2.703; 95% confidence interval (CI) 1.013-7.211; P=.047), left ventricular ejection fraction (HR=.970; 95%CI .944-.997; P=.032), indexed end-diastolic left ventricular diameter (HR=15.165; 95%CI 4.498-51.128; P<.001), indexed left atrial diameter (HR=1.107; 95%CI 1.045-1.173; P=.001), tricuspid valve prolapse (HR=2.599; 95%CI 1.243-5.437; P=.011), posterior leaflet prolapse (HR=1.075; 95%CI 1.023-1.130; P=.009), and posterior leaflet thickening (HR=3.368; 95%CI 1.265-8.968; P=.015) with progression of mitral valve disease, whereas none of the FBN1 gene mutation characteristics were associated with progression of mitral valve disease. However, Cox regression analysis identified a marginal relationship of FBN1 gene mutations located both in a transforming-growth-factor beta-binding protein-like (TGFb-BP) domain (HR=3.453; 95%CI .982-12.143; P=.053), and in the calcium-binding epidermal growth factor-like (cbEGF) domain (HR=2.909; 95%CI .957-8.848; P=.060) with mitral valve surgery, a finding that was corroborated by Kaplan-Meier analysis (P=.014; and P=.041, respectively). CONCLUSION: Clinical features were better predictors of mitral valve disease progression than FBN1 gene mutation characteristics.

Frequency and age-related course of mitral valve dysfunction in the Marfan syndrome.

Mitral valve (MV) prolapse (MVP) has a high prevalence of 2% to 3% in the general population and thus constitutes the most common cause of severe nonischemic MV regurgitation (MVR). MVP is also common in persons with the Marfan syndrome. However, to date, a large-scale population-based cohort study using modern echocardiographic techniques has not been performed, and the frequency of MVP and the relation of MV dysfunction and age have not been investigated. Therefore, we conducted a population-based cohort study of 204 patients (108 males and 96 females, aged 31.2 ± 16.4 years) with classic Marfan syndrome. We performed echocardiographic follow-up of 174 patients for a mean of 4.4 ± 4.3 years. On the initial or subsequent echocardiographic scan, MVP was present in 82 patients (40%), severe MVR in 25 (12%), and MV endocarditis in 5 patients (2.5%). At 30 years of age, the Weibull cumulative distribution was 42.6% (95% confidence interval [CI] 36% to 50%) for MVP, 56.5% (95% CI 49.3% to 64%) for MVR of any degree, 6.7% (95% CI 3.9% to 11.3%) for severe MVR, and 0.92% (95% CI 0.21% to 3.91%) for MV endocarditis. The cumulative hazard for severe MVR and MV endocarditis was estimated to increase with age. MVP was associated with dural ectasia (p = 0.01), ectopia lentis (p = 0.02), and skeletal involvement (p <0.001). Severe MVR was related to tricuspid valve prolapse (p = 0.002) and to the sporadic form of the Marfan syndrome (p = 0.006). In conclusion, MVP was comparatively frequent in patients with the Marfan syndrome and carries an increased risk of progression to severe MVR and endocarditis, especially in older adults.

Augmentation index and the evolution of aortic disease in marfan-like syndromes.

BACKGROUND: The augmentation index at a heart rate of 75 beats/min (AIx@HR75) and central pulse pressure (CPP) can be measured noninvasively with applanation tonometry (APT). In this observational study, we investigated the relationship between AIx@HR75, CPP and aortic disease in patients with Marfan-like syndromes. METHODS: We performed APT in 78 consecutive patients in whom classic Marfan syndrome (MFS) had been excluded (46 men and 32 women aged 34 +/- 13 years). These patients comprised 9 persons with MFS-like habitus, 6 with a bicuspid aortic valve (BAV), 5 with MASS phenotype, 3 with vascular type of Ehlers-Danlos syndrome (EDS), 3 with familial thoracic aortic aneurysm, 2 with Loeys-Dietz syndrome (LDS), 1 with mitral valve prolapse syndrome, 1 with familial ectopia lentis, and 48 persons with Marfan-like features but no defined syndrome. During 20 +/- 18 months after APT, we observed progression of aortic diameters in 15 patients, and aortic surgery or aortic dissection in 3 individuals. RESULTS: All 11 patients with Marfan-like syndromes and progression of aortic disease exhibited AIx@HR75 > or =11%, including 8 individuals with aortic diameters < or =95th percentile of normal at baseline. Similarly, all 7 individuals without any defined syndrome but progression of aortic diameters exhibited AIx@HR75 >11%, including 6 individuals with aortic diameters < or =95th percentile at the time of APT. Aortic disease did not evolve at AIx@HR75 <11%. CPP is also related to aortic disease progression. CONCLUSIONS: Aortic disease evolution relates to AIx@HR75 and CPP in Marfan like syndromes. Larger studies with comprehensive clinical and echocardiographic follow-up over long time intervals will be required to establish APT for prediction of aortic disease evolution in Marfan-like syndromes.