Resumo (PT):
Objective: Age and hypertrophy are major determinants of diastolic function. Diastolic dysfunction (DD) is the result of increased myocardial stiffness and extracellular factors like fibrosis. Our aim was to determine if age was an independent predictor of DD in aortic stenosis (AS) and to explore its pathophysiology. Methods: Prospective study of 55 patients with isolated AS undergoing aortic valve replacement (AVR). Exclusion criteria: other significant valve lesions (>mild), significant coronary artery disease (>50%), atrial fibrillation. Demographic, clinical and echocardiographic data were analyzed before and 6 months after AVR. The percentage of interstitial fibrosis (n=11), individual cardiomyocyte passive tension (n=15), and the relation between titin isoforms N2BA/NAB (n=7) was determined from myocardial biopsies collected during surgery, after patient consent. Continuous variables were summarized as median (interquartile range (P25-75)). Results: In this sample 58.2% were female (n=32), median age 66.0 years (P25-75: 59.5-73.0yrs). History of hypertension in 52.7% (n=29) and diabetes mellitus in 16.4% (n=9). Median relative mass regression after AVR was 19.1% (P25-75: 7.6-29.3). Median percentage of interstitial fibrosis was 11.5% (P25-75: 10.7-12.7), median passive tension was 2.75 (P25-75: 2.01-3.82) and median N2BA/N2B was 0.5 (P25-75:0.42-0.63). Patients with DD at baseline were older (no DD: 49.0, P25-75: 29.3-49yrs; with DD: 67, P25-75: 60.0-67.0yrs; p=0.03). Older patients had lower baseline E/A (r=-0.25, p=0.043), higher E/e´ (r=0.39, p=0.001) and larger left atrium diameter (r=0.27, p=0.06). Older age was also associated with lower E/A (r=-0.46, p<0.001) and lower e´ (r=0.31, p=0.02) at six months. The relative expression of rigid N2B titin isoform increased with age (N2BA/ N2B: r=-0.95, p=0.001), with no significant change in fibrosis or cardiomyocyte passive tension. Conclusions: Our results suggest that older age is related with DD in patients with isolated aortic stenosis before and 6 months after AVR. Higher expression of the rigid N2B titin isoform in older patients may, at least partially, account for these diastolic differences.
Language:
English
Type (Professor's evaluation):
Scientific
Notes:
XXX Congresso Português de Cardiologia, publicado na Rev. Port. Cardiol. 2009; Vol.28:(Supl.I):I-28