| (Part 1)Long-term Natural History of Ascending Aorta after Surgical Valve Replacement:Echocardiographic Follow-upBackground Surgical valve replacement (SVR) is the recommended and most effective treatment of valvular heart disease (VHD), which is often referred to rheumatic heart disease (RHD) in China. To date, many studies demonstrated that patients referred for valve replacement often have accompanying ascending aortic dilatation. Unfortunately, there is little information about the postoperative evolution of ascending aorta (AAo) after SVR in China.Objective The present clinical study was aimed to demonstrate the natural history of AAo following aortic valve replacement (AVR) or double valve replacement (DVR).Methods We studied population who underwent SVR at our institution between Jan.1998 and Dec.2010. Clinical and echocardiographic data was obtained by merging and searching our institutional echocardiographic database with the medical record system of Cardiovascular Disease & Fuwai Hospital database. The etiology of the SVR was divided into three groups:rheumatic heart disease (RHD), degenerative aortic valve (DAV) and aortic valve prolapse (AVP). In order to observe the dimensions of the AAo at different time, the follow-up periods were split into 4 subgroups:≤3 year,<3 year～≤6 year,＜6 year～≤9 year,＞9 year. Additionally, the baseline ascending aorta diameter is classified into three groups:≤30mm,＞ 30mm～≤35mm, and>35mm, to observe the changes of the diameter of the AAo. All data were collected and analyzed with Microsoft Excel and SPSS 16.0. Probability values<0.05 were considered significant.Results Data from 1665 patients (the mean age was 47.0 ± 10.8 years and was predominately 877 female) with 10763 echocardiographic imaging were analyzed. The mean duration of follow-up was 7.59 ± 3.38 years. At baseline, AAo diameter ranged from 20mm-53mm with a mean of 31.97 ± 4.95mm. The mean AAo expansion rate in the entire study was 0.45 ± 3.75mm. The baseline AAo was significantly wider in various etiologies (31.21 ± 4.62mm vs.35.36 ±5.08mm vs. 33.45±4.90mm, P<0.05). During follow-up examination, the dimensions of the AAo at different follow-up stage were more than the baseline. After valve replacement, the postoperative AAo diameter showed a trend of overall growth and mean values of the AAo in each group were higher than the baseline (P<0.05). The broadening rate of the AAo was 17.89%～44.27% after SVR. The proportion of AAo diameter≥40 mm in the DAV group accounted for the proportion to 27.08%, followed by AVP group was 16.87%. RHD only a few displayed an increase in diameter exceeding 40 mm. The increase tendency of the baseline AAo diameter> 35mm is higher than≤30mm and>30mm～35mm. The proportion of dilation RHD, DAV, and AVP in>35mm group was 57.74%,67.14 and 68.00%, respectively.Conclusion With the extension of follow-up study, there is an increase in the dimensions of AAo following SVR, either the inner diameter, or the proportion, all showed a gradual increase. The average diameter in degenerative aortic valve disease patients was greater than those in aortic valve prolapse and rheumatic heart disease. Furthermore, degenerative aortic valve disease has the biggest growth trend. However, the average diameter of rheumatic heart disease was the smallest and the growth trend was also minimal. Therefore, the increase rate of RHD was significantly lower than that of AVP and DAV. A significant dilatation of the AAo diameter>35mm was observed after SVR, in patients when a cut-off diameter of 40mm or greater was considered.(Part 2)Risk Factors for Dilatation of Ascending Aorta in Rheumatic Heart Disease Following Valve ReplacementBackground Rheumatic heart valve disease is one of the most common heart diseases in China. Surgical valve replacement is the most effective and reliable treatment for this disease at present. To date, many studies demonstrated that patients referred for valve replacement often have accompanying ascending aortic dilatation.However, there is much controversy about the natural history of ascending aorta following valve replacement.Objective We sought to identify the risk factors for dilatation of ascending aorta in RHD and to assess the predictors.Methods Data were analyzed from 1230 consecutive RHD patients underwent SVR between Jan.1998 and Dec.2010. Clinical and echocardiographic data were obtained by merging and searching our institutional echocardiographic database with the medical record system of Cardiovascular Disease, Fuwai Hospital database. Therefore, subgroups-analysis of the RHD were performed. All data were collected and analyzed with Microsoft Excel and SPSS 16.0. Probability values<0.05 were considered significant. Binary logistic regression analysis model was used to evaluate contribution of several factors for the dilatation of ascending aorta in RHD.Results Retrospective study of 1230 cases with heart valve replacement demonstrated that there was an increase in the mean AAo diameter. At baseline, ascending aorta (AAo) diameters ranged from 20mm-52mm with a mean of 31.21 ± 4.62mm. The mean AAo expansion rate in the entire study was 0.41±3.64 mm. During follow-up examination, there was a significant increase in the mean AAo diameter and the proportion of dilated AAo in RHD. The proportion of AAo diameter ≥40 mm in the aged, male, high degree of aortic incompetence/steonos were more significantly higher than those in young, female, low degree of aortic incompetence/ steonos. Logistic regression analysis suggested that the size of prosthetic valve, the degree of arotic insufficiency, hypertension, the degree of arotic steonos, gender, NYHA and age were risky factors of the dilatation of ascending aorta in RHD following surgical valve replacement (with odds ratios respectively:2.235,2.067, 1.687,1.667,1.666,1.362,1.030, P<0.05).Conclusions As the follow-up visit increasing, there is an increase in AAo dilatation occurs frequently following SVR. The size of prosthetic valve, the degree of arotic insufficiency, hypertension, the degree of arotic steonos, gender, NYHA and aged are the risk factors of the expansion of the ascending aorta. Compared with aortic stenosis, aortic regurgitation is likely to be strong predictors for the dilation of AAo. There was a high frequency of aortic events in patients with AAo＞35mm subgroup, which need close postoperative follow-up. In order to avoid adverse events and choosing the proper time of surgery again. Preoperative AAo diameter may be important reference factors of operation choice.
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