| Bcakgroud and ObjectionAortic valve stenosis (AS) is a hemodynamically significant narrowing of the outlet of the left ventricle with multiple potential etiologies,which is commonly caused by rheumatism,congenital heart defect,senile aortic valve calcification and so on.According to a relative report,the prevalance of AS is approximately 2% in the population aged over 65 years, and 4% in those between 75 to 85,and 6% in those over 85. Data by Chinese National Statistical Bureau in 2012 shows that the number of peole aged over 65 in China were about 127.14 million.A normal aortic valve area is approximately 3-4 cm2 and symptoms of AS tend to develop when the aortic valve area is 1 cm2 or less.It has reached the level of ’severe’according to the guidelines of American Heart Association/American College of Cardiology (AHA/ACC) and European Association of Echocardiography /American Society of Echocardiography (EAE/ASE).For a long time, surgical aortic valve replacement under extracorporeal circulation was consider as the’golden standard’for the treatment of severe AS. However, nearly 30% to 60% of senior patients with severe AS are denied by SAVR because of the comorbidities and expected with poor surgical outcome. Though interventional balloon aortic valvularplasty (BAV) and aortic valve replacement under thoracoscope may bring some help, their obvious disadvantages are still difficult to swallow.The introduction of transcatheter aortic valve implantation (TAVI) in 2002, which make it possible to implant a heart valve through interventional treatment in human being, provided a new therapy for AS.Among different accesses of TAVI, tranfemoral AVI (TF-AVI) and transapical AVI (TA-AVI) are the most widely usages.Moreover,TF-AVI is as’first choice’in majorty of medical centers for its’obvious minimally invasive’, and doctors turn for another access unless TF-AVI is impossible for poor peripheral vessel conditions.However, some other scientists propose opposite opinions. Compared with TF-AVI, TA-AVI per se offers plenty of advantages as it is antegrade, is very close to the target, gains less dislocation, allows a very controlled implantation. Besides the above, TA-AVI also requires nothing from peripheral vessles, noninterference to aortic orch, and leads to less incidence of vascular injury or stroke.To date, no consensuses on the outcomes of TF-AVI and TA-AVI have been established, though there have been several published studies of registered clinical trials comparing TF-AVI and TA-AVI for treating patients with severe AS. Furthermore, a few meta-analyses were conducted to explore the answer, but may be insufficient for the reasons as follows:(1) a small mount of studies;(2) no results of more than one year after procedure;(3) no comparison after kicking or reducing the effects of learning curve. We wish our study could make a supplement to previous ones, and offer more evidence to the treating of severe AS.Methods and MaterialsOur meta-analysis was conducted in compliance with recommendations from PRISMA (preferred reporting items for systematic reviews and meta-analyses).The major inclusion criteria were as follows:(1) patients diagnosed with severe AS, and no limitations on comorbidities;(2) assessing TF-AVI versus TA-AVI specifically, or SAVR versus TAVI with outcome details of both TF-AVI and TA-AVI; (3) containing original data sufficient for calculating the relative ratio (RR) or p value,and published in English, while with no restrictions on publication types;(4) reporting at least one pertinent clinical outcome of all-cause mortality (ACM), stroke/TIA, major vascular events (MVE),major bleeding events (MBE) and myocardial infarction (MI).Studies were excluded according to the following criteria: (1) unreasonable design; (2) not reporting the outcomes of both TF-AVI and TA-AVI simultaneously; (3) irretrievable or insufficient data for statistical analysis; (4) duplication; (5) unavailable full text of original articles.Medline (PubMed interface), Embase and the Cochrane Library were searched without any restrictions on publication status, type, date. The last search was conducted on December 31th,2014.Each outcome complied the criteria of VARC (Valve Academic Research Consortium). We extracted not only the outcomes but also the baseline of characteristics of the studies included. When comparing ACM between the two groups, we conducted different time points including in-hospital,30-day, 1-year,and 2-year after the procedure. And due to the lack of data, we only performed the 30-day results of stroke/TIA, MVE, MBE and MI. For non-randomized cohort studies, the Newcastle-Ottawa scale (NOS) was used for assessing the methodological quality of the observational studies. Quality evaluation of the included randomized controlled trials (RCTs) were performed according to the Cochrane Collaboration’s tool for assessing risk of bias (5.1.0).The final relative ratio (RR) across all studies with the corresponding 95% confidence interval (CI) was calculated for each end point for dichotomous outcomes, respectively. Heterogeneity was measured by using the chi-squared test and calculating the I2 and Phet statistic.Heterogeneity of the studies was assessed for each end point. Studies that were homogenous (I2= 50%) for an end point were analyzed by using the Mantel-Haenszel fixed-effect model, and studies that were heterogenous (I2>50%) for an end point were analyzed by using the random-effect model.And sensitivity analyses were performed by deselecting studies one by one to detect the influence of each study on I2 and the pooled RR. Publication bias were also analyzed using a funnel-plot method in combined results with more than 5 studies included. All P values were 2-sided, of which except Phet the significance level was set at 0.05. All calculations and figures were conducted by using Review Manager 5.3.Results26 eligible studies with acceptable quality met the inclusion criteria. They were all observational studies and included for the analysis, containing 15 single-center studies and 11 multi-central ones. Further more, there were also 7 studies of large singl-center defined as that the number of TF-AVI and TA-AVI were both more than 40. When taken together,10062 patients were included, of which 6968 patients underwent TF-AVI and 3094 patients underwent TA-AVI.1. ACM8 studies were involved for analyzing in-hospital ACM. In all of these studies, a total of 1645 patients with AS underwent TF-AVI (n=1195) or TA-AVI (n=450) were included. The cumulative incidences of in-hospital ACM of TF-AVI was lower than TA-AVI,with RR [CI]= 0.56 [0.39,0.81] (P= 0.002; 12= 0%, Phet= 0.47). Similar result was obtained in subgroup of 3 large single-centers, with RR[CI]=0.51 [0.28,0.92] (P=0.02; 12=0%, Phet= 0.56).24 studies were involved for analyzing 30-day ACM. In these all studies, a total of 9105 patients with AS underwent TF-AVI (n=6124) or TA-AVI (n=2981) were included. The cumulative incidences of 30-day ACM of TF-AVI was lower than TA-AVI,with RR [CI]= 0.59 [0.51,0.68](P< 0.00001; I2= 0%,Phet= 0.60). However, significant difference was not detected in 7 large single-centers with a total of 1465 patients between TF-AVI and TA-AVI at 30 days after procedures, with RR[CI]=0.741[0.53,1.03] (P=0.07; I2=0%, Phet=0.73).With the extend of follow-up, similar consequence was found in 1-year ACM between TF-AVI and TA-AVI.14 studies were involved to compare 1-year ACM with a number of 6728 patients treated by TAVI, and a higher mortality was detected in TA-AVI, RR[CI]=0.71 [0.61,0.83] (P< 0.0001,I2=52%, Phet= 0.01). However, the statistical difference disappeared at 1 year after TAVI, with RR[CI]=0.98[0.75,1.29] (P=0.90; I2=41%, Phet=0.17.Only 3 studies was included to combine and analyse for 2-year ACM between TF-AVI and TA-AVI. No statistical difference was detected,with RR[CI]=0.98[0.68,1.43] (P=0.93; I2= 82%, Phet=0.004). There was 1 study of large single-center with RR[CI]=1.52[0.98,2.53].2.30-day stroke/TIA19 studies were involved for analyzing 30-day stroke/TIA, containing a total of 6093 patients with AS underwent TF-AVI (n=3890) or TA-AVI (n=2203). The cumulative incidences of 30-day stroke/TIA of TF-AVI was similar to TA-AVI in all centers and the subgroup of large singl-centers,with RR[CI] of 1.07[0.79,1.44] (P =0.66; I2=0%, Phet=0.67),and 1.58[0.88,2.82] (P=0.12; I2-13%, Phet=0.33), respectively.3.30-day MVE13 studies were involved for analyzing 30-day MVE, and 4 came from large single-centers. No matter in all centers or large single-centers, more than 2 times of incidence of 30-day MVE was found in TF-AVI comparing to TA-AVI, with RR[CI] of 2.66[1.94,3.63](P<0.00001;I2=12%, Phet=0.32), and 2.63[1.45,4.75] (P=0.001; I2= 15%, Phet=0.32) respectively.4.30-day MBE7 studies with 1602 patients from all centers were combined and analysed for 2-year ACM between TF-AVI and TA-AVI. No statistical difference was detected,with RR[CI]=0.84[0.67,1.07] (P=0.16;I2=45%, Phet=0.09). There were only 2 studies of large single-centers, and it was insufficient to perform combination and analysis.5.30-day MI11 studies were involved to compare 1-year ACM with a number of 6728 patients treated by TAVI, but 3 studies reported no MI at 30 days atfer procedure. A lower incidence of MI was identified in TA-AVI, RR[CI]=0.46[0.24,0.88](P=0.02; I2= 0%, Phet=0.87). It could not conduct subgroup analysis due to the lack of data in large single-centers.6. Publication biasFunnel plots were constructed for visual evaluation of publication bias. None except for the meta-analysis of 30-day MBE presented significant publication bias.Conclusion1. When consideration of operational experience was removed, in all centers, during the short- and mid-term (in-hospital,30-day,1-year), TF-AVI presented better outcomes of ACM than TA-AVI, but similar at 2 year after TAVI; Parallel outcomes of 30-day stroke, MBE, MI were gained in the two groups but TF-AVI was more dangerous than TA-AVI on MVE.2. In consideration of operational experience, combined data of large single-centers showed that less in-hospital death may happened in TF-AVI, but the difference disappeared along with follow-up (30-day,1-year); Incidence of 30-day stroke/TIA remained similar in two groups, and TF-AVI still presented poorer than TA-AVI on 30-day MVE.3. Whether TA-AVI might cause more 30-day MBE than TF-AVI remains unclear and requires more investigations. |
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