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TAVI conferred similar late (≥2 years) all-cause mortality compared to SAVR.
•
All-cause mortality differed significantly from randomized control trial and propensity-matched studies.
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A meta-regression suggested TAVI offered better outcomes with higher age and proportion of coronary artery disease.
Abstract
Introduction
Transcatheter aortic valve implantation (TAVI) has shown non-inferior late mortality in severe aortic stenosis (AS) patients in intermediate to inoperable risk for surgery compared to surgical aortic valve replacement (SAVR). Late outcome of TAVI compared to SAVR is crucial as the number of TAVI continues to increase over the last few years.
Methods
A comprehensive literature search of PUBMED and EMBASE were conducted. Inclusion criteria were that [1] study design was a randomized controlled trial (RCT) or a propensity-score matched (PSM) study: [2] outcomes included >2-year all-cause mortality in both TAVI and SAVR. The random-effects model was utilized to calculate an overall effect size of TAVI compared to SAVR in all-cause mortality. Publication bias was assessed quantitatively with Egger's test.
Results
A total of 14 studies with 6503 (3292 TAVI and 3211 SAVR, respectively) were included in the meta-analysis. There was no difference in late all-cause mortality between TAVI and SAVR (HR 1.17, 95%CI 0.98–1.41, p = 0.08, I2 = 61%). The sub-group analysis of all-cause mortality of RCT (HR 0.93 95%CI 0.78–1.10, p = 0.38, I2 = 40%) and PSM studies (HR 1.44 95%CI 1.15–1.80, p = 0.02, I2 = 35%) differed significantly (p for subgroup differences = 0.002). Meta-regression implicated that increased age and co-existing CAD may be associated with more advantageous effects of TAVI relative to SAVR on reducing late mortality. There was no evidence of significant publication bias (p = 0.19 for Egger's test).
Conclusions
TAVI conferred similar late all-cause mortality compared to SAVR in a meta-analysis of RCT but had worse outcomes in a meta-analysis of PSM.
Since the successful first in man case of transcatheter aortic valve implantation (TAVI) in a patient with inoperable, symptomatic severe aortic stenosis (AS) in 2002 by Cribier et al., the number of TAVI performed worldwide has been dramatically increasing [
Patients at intermediate risk are expected to have the longer life expectancy after TAVI compared to those at high or inoperable risk. The data on late outcomes after TAVI is starting to accumulate. Several studies have reported 3 to 7 years of outcome data after TAVI [
Long-term outcomes after transcatheter aortic valve replacement in high-risk patients with severe aortic stenosis: the U.K. Transcatheter Aortic Valve Implantation Registry.
]. However, a number of studies that have reported comparative late outcomes between TAVI and surgical aortic valve replacement (SAVR) are relatively limited. The United States CoreValve Registry showed all-cause mortality favoring TAVI (p = 0.068) during 3 years follow-up, while the Placement of AorRTic TraNscathetER (PARTNER) valve trial have reported similar 5 years all-cause mortality [
5-year outcomes of transcatheter aortic valve replacement or surgical aortic valve replacement for high surgical risk patients with aortic stenosis (PARTNER 1): a randomised controlled trial.
]. Recent other meta-analyses showed improved mortality in TAVI than SAVR during up to 2 years or median of 2 (range 3 months to 3 years) years follow-up with limited number of studies [
Transcatheter aortic valve implantation vs. surgical aortic valve replacement for treatment of severe aortic stenosis: a meta-analysis of randomized trials.
Transcatheter versus surgical aortic valve replacement in patients with severe aortic stenosis at low and intermediate risk: systematic review and meta-analysis.
]. We have previously published meta-analysis of TAVI vs SAVR using propensity-score analysis and concluded that TAVI had worse outcome compared to SAVR [
ALICE (All-Literature Investigation of Cardiovascular Evidence) Group
Worse survival after transcatheter aortic valve implantation than surgical aortic valve replacement: a meta-analysis of observational studies with a propensity-score analysis.
5-year outcomes of transcatheter aortic valve replacement or surgical aortic valve replacement for high surgical risk patients with aortic stenosis (PARTNER 1): a randomised controlled trial.
A prospective, randomised trial of transapical transcatheter aortic valve implantation vs. surgical aortic valve replacement in operable elderly patients with aortic stenosis: the STACCATO trial.
Transcatheter versus surgical aortic valve replacement in patients with severe aortic valve stenosis: 1-year results from the all-comers NOTION randomized clinical trial.
ALICE (All-Literature Investigation of Cardiovascular Evidence) Group
Worse survival after transcatheter aortic valve implantation than surgical aortic valve replacement: a meta-analysis of observational studies with a propensity-score analysis.
5-year outcomes of transcatheter aortic valve replacement or surgical aortic valve replacement for high surgical risk patients with aortic stenosis (PARTNER 1): a randomised controlled trial.
]. It is of great clinical importance to assess the comparative late outcomes between TAVI and SAVR to better provide physicians and patients the best available evidence to aid their decisions.
Therefore, we aimed to compare further late outcomes (≥2 years) through systematic review and meta-analysis using HR to better estimate the effect size of TAVI versus SAVR.
2. Methods
2.1 Literature search strategy
A systematic literature search of PUBMED and EMBASE was performed by two independent reviewers (T.A. and H.T.). There were no language limitations and conference abstracts were excluded. Search was performed on March 23rd, 2016 from January 1st, 2004. Search terms were “aortic valve” AND (percutaneous OR transcatheter OR transluminal OR transarterial OR transapical OR transaortic OR transcarotid OR transaxillary OR transsubclavian OR transiliac OR transfemoral OR transiliofemoral OR “Transcatheter Aortic Valve Replacement” [Mesh]) AND (mortality OR death OR deaths OR survival) AND (propensity OR randomized control). Titles and/or abstracts were screened based on inclusion and exclusion criteria. Studies were included when 1: All-cause mortality was reported for more than two years follow-up in both TAVI and SAVR cohort represented by survival curve 2: HR for all-cause mortality or OR were able to abstract or calculate for late events from the provided information 3: if the study design were either RCT or propensity-matched (PSM) cohort study. Exclusion criteria were 1: single arm study of either TAVI or SAVR. 2: when TAVI outcomes were compared with sutureless aortic valve replacement outcomes and 3: conference abstracts. When more than one study was reported in the same database, the study with the longest study was selected. When the follow-up duration was the same, the study with the most cohorts was selected. The meta-analysis was performed in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) and MOOSE (Meta-analysis of Observational Studies in Epidemiology) guidelines [
Meta-analysis of observational studies in epidemiology: a proposal for reporting. Meta-analysis of Observational Studies in Epidemiology (MOOSE) group.
]. Disagreements were resolved by a discussion by the 2 authors (T.A. and H.T.) to reach a consensus.
2.3 Statistical analysis
Categorical values were expressed as percentages and continuous values as a mean ± standard deviation. The generic inverse variance was used to calculate the pooled HR/OR and 95% confidence intervals (CI). When HR was not available from the text, first we used methods proposed by Parmar et al. and when crude event rates were not available, methods proposed by Tierney et al. [
] was utilized to estimate the HR and its 95%CI from the Kaplan-Meier curve analysis. Publication bias was assessed visually from the funnel plot and if concern existed for asymmetry, Egger's test was utilized to quantitatively assess the publication bias. Publication bias was not assessed when <10 studies were included in the meta-analysis for each outcome. Meta-regression analysis was performed by unrestricted maximum likelihood method with continuous variables as a moderator. Variables were pre-specified for the meta-regression analysis. A p-value < 0.05 was considered significant. When 95% CI of either OR or HR for TAVI vs SAVR does not cross one, TAVI (upper limit of 95% CI is below one) or SAVR (lower limit of 95% CI is above on) significantly favors reducing clinical outcomes. Meta-analyses were performed with the Review Manager (RevMan) Version 5.3 (Nordic Cochrane Centre, The Cochrane Collaboration, 2012, Copenhagen, Denmark) and Comprehensive Meta-analysis version 2 and 3 (Biostat, Englewood, NJ)
3. Results
Our search result yielded a total of 616 results. Detailed study flow diagram is shown in Table 1. A total of 14 studies including 6503 (3292 TAVI and 3211 SAVR) patients were finally analyzed in this meta-analysis. Four studies [
5-year outcomes of transcatheter aortic valve replacement or surgical aortic valve replacement for high surgical risk patients with aortic stenosis (PARTNER 1): a randomised controlled trial.
Two-year outcomes in patients with severe aortic valve stenosis randomized to transcatheter versus surgical aortic valve replacement: the all-comers Nordic aortic valve intervention randomized clinical trial.
Early and midterm outcome of propensity-matched intermediate-risk patients aged ≥80 years with aortic stenosis undergoing surgical or transcatheter aortic valve replacement (from the Italian Multicenter OBSERVANT Study).
A comparison of conventional surgery, transcatheter aortic valve replacement, and sutureless valves in “real-world” patients with aortic stenosis and intermediate- to high-risk profile.
Propensity matched analysis of longterm outcomes following transcatheter based aortic valve implantation versus classic aortic valve replacement in patients with previous cardiac surgery.
A comparison of transcatheter aortic valve implantation and surgical aortic valve replacement in 1,141 patients with severe symptomatic aortic stenosis and less than high risk.
Transapical transcatheter aortic valve implantation vs conventional aortic valve replacement in high-risk patients with previous cardiac surgery: a propensity-score analysis.
] were reported to be more prevalent in SAVR. Characteristics of patients included in each study for TAVI and SAVR are summarized in table 1. Overall, the patients' baselines were well matched in all studies. The flow of the study selection is summarized in Fig. 1.
Table 1Characteristics summary of included studies.
Two-year outcomes in patients with severe aortic valve stenosis randomized to transcatheter versus surgical aortic valve replacement: the all-comers Nordic aortic valve intervention randomized clinical trial.
Early and midterm outcome of propensity-matched intermediate-risk patients aged ≥80 years with aortic stenosis undergoing surgical or transcatheter aortic valve replacement (from the Italian Multicenter OBSERVANT Study).
5-year outcomes of transcatheter aortic valve replacement or surgical aortic valve replacement for high surgical risk patients with aortic stenosis (PARTNER 1): a randomised controlled trial.
A comparison of conventional surgery, transcatheter aortic valve replacement, and sutureless valves in “real-world” patients with aortic stenosis and intermediate- to high-risk profile.
Propensity matched analysis of longterm outcomes following transcatheter based aortic valve implantation versus classic aortic valve replacement in patients with previous cardiac surgery.
A comparison of transcatheter aortic valve implantation and surgical aortic valve replacement in 1,141 patients with severe symptomatic aortic stenosis and less than high risk.
Transapical transcatheter aortic valve implantation vs conventional aortic valve replacement in high-risk patients with previous cardiac surgery: a propensity-score analysis.
Two-year outcomes in patients with severe aortic valve stenosis randomized to transcatheter versus surgical aortic valve replacement: the all-comers Nordic aortic valve intervention randomized clinical trial.
Early and midterm outcome of propensity-matched intermediate-risk patients aged ≥80 years with aortic stenosis undergoing surgical or transcatheter aortic valve replacement (from the Italian Multicenter OBSERVANT Study).
5-year outcomes of transcatheter aortic valve replacement or surgical aortic valve replacement for high surgical risk patients with aortic stenosis (PARTNER 1): a randomised controlled trial.
A comparison of conventional surgery, transcatheter aortic valve replacement, and sutureless valves in “real-world” patients with aortic stenosis and intermediate- to high-risk profile.
Propensity matched analysis of longterm outcomes following transcatheter based aortic valve implantation versus classic aortic valve replacement in patients with previous cardiac surgery.
A comparison of transcatheter aortic valve implantation and surgical aortic valve replacement in 1,141 patients with severe symptomatic aortic stenosis and less than high risk.
Transapical transcatheter aortic valve implantation vs conventional aortic valve replacement in high-risk patients with previous cardiac surgery: a propensity-score analysis.
Two-year outcomes in patients with severe aortic valve stenosis randomized to transcatheter versus surgical aortic valve replacement: the all-comers Nordic aortic valve intervention randomized clinical trial.
Early and midterm outcome of propensity-matched intermediate-risk patients aged ≥80 years with aortic stenosis undergoing surgical or transcatheter aortic valve replacement (from the Italian Multicenter OBSERVANT Study).
5-year outcomes of transcatheter aortic valve replacement or surgical aortic valve replacement for high surgical risk patients with aortic stenosis (PARTNER 1): a randomised controlled trial.
A comparison of conventional surgery, transcatheter aortic valve replacement, and sutureless valves in “real-world” patients with aortic stenosis and intermediate- to high-risk profile.
Propensity matched analysis of longterm outcomes following transcatheter based aortic valve implantation versus classic aortic valve replacement in patients with previous cardiac surgery.
A comparison of transcatheter aortic valve implantation and surgical aortic valve replacement in 1,141 patients with severe symptomatic aortic stenosis and less than high risk.
Transapical transcatheter aortic valve implantation vs conventional aortic valve replacement in high-risk patients with previous cardiac surgery: a propensity-score analysis.
Because we observed high heterogeneity, we performed sensitivity analysis. First, we performed a subgroup analysis based on study design, RCT or a PSM study. Meta-analysis of only the RCT (1895 TAVI and 1866 SAVR) did not show the difference in all-cause mortality between TAVI and SAVR (HR 0.93, 95%CI 0.78–1.10, p = 0.38, I2 = 40%). However, pooled HR of only the PSM studies (1397 TAVI and 1345 SAVR) showed significantly worse mortality in TAVI (HR 1.44, 95%CI 1.15–1.80, p = 0.002, I2 = 35%). There was significant heterogeneity between subgroup (I2 = 89.3%, p for subgroup differences = 0.002). This resulted in non-significant heterogeneity in both groups.
Second, study with the largest weight (19.4% = 10.8% for transfemoral +8.6% for transthoracic) [
] was removed but did not significantly alter the result (HR 1.23, 95%CI 0.99985–1.51, p = 0.05, I2 = 60%). Third, studies with a cohort of <100 were removed (PMID: 26, 30, 32–34) but the result was consistent (HR 1.19, 95%CI 0.94–1.52, p = 0.16, I2 = 73%). Fourth, every each study was removed once at a time. When a study by Deeb et al. [
] was removed, the overall effect was in favor of SAVR (HR 1.23, 95%CI 1.02–1.48, p = 0.03, I2 = 56%). However, when each study was removed at a time for the each subgroup (RCT only meta-analysis and PSM only meta-analysis), it did not significantly affect the result.
We performed a meta-regression analysis with a pre-specified clinical baseline to further investigate the source of heterogeneity.
As the age or the prevalence of coronary artery disease (CAD) increases, the HR of late mortality (for TAVI vs SAVR) significantly decreases. This result implicates that TAVI was more effective in reducing the HR of late-mortality compared to SAVR in higher age and patients with CAD. The results of meta-regression for other clinical baselines are summarized in Table 2 and were not significant.
Table 2Meta-regression analysis.
Variable
Number of studies
Slope
Lower limit
Upper limit
p-Value
Age
14
−0.091
−0.15
−0.0033
0.0021
Men
14
−0.0088
−0.027
0.0088
0.33
DM
12
−0.0082
−0.031
0.015
0.48
STS
8
0.035
−0.050
0.12
0.18
Logistic EuroSCORE
11
0.015
−0.020
0.038
0.53
Follow up length
14
0.11
−0.017
0.24
0.088
BMI
8
−0.16
−0.40
0.074
0.18
CAD
9
−0.014
−0.0026
−0.0023
0.019
PAD
12
0.0029
−0.012
0.0018
0.70
Publication year
14
−0.054
−0.29
0.089
0.33
DM: diabetes, STS: society of thoracic surgeon, BMI: body mass index, CAD: coronary artery disease, PAD: peripheral artery disease.
Late cardiovascular mortality (1895 and 1866 patients from TAVI and SAVR, respectively, from 4 RCT) did not differ between TAVI and SAVR (OR 1.01, 95%CI 0.78–1.29, p = 0.95, I2 = 43%). From the same 4 RCT studies, late stroke (OR 0.83 95%CI 0.65–1.05, p = 0.13, I2 = 0%) and myocardial infarction (OR 0.83 95%CI 0.57–1.21, p = 0.33, I2 = 0%) were also similar between TAVI and SAVR. There was no significant heterogeneity observed for late cardiovascular mortality, myocardial infarction and stroke. Sensitivity analysis (by omitting one study at a time and recalculating the pooled effect size) did not significantly alter the pooled effect size for cardiovascular mortality, stroke, and myocardial infarction. The results are summarized in Fig. 3.
Fig. 3Random-effects model forest plot for cardiovascular mortality, stroke and myocardial infarction.
Publication bias was assessed for all-cause mortality including 14 studies and did not show significant publication bias (p = 0.19 for Egger's test).
For other outcomes, publication bias was not assessed because the included studies were <10.
Study quality for RCTs showed risk of bias was low for all the studies. Newcastle-Ottawa score showed >7 for all included studies for the PSM studies.
4. Discussion
Our major findings of this meta-analysis were that 1: Late (≥2 years) all-cause mortality of TAVI was comparable to SAVR. However, the all-cause mortality of RCT and PSM studies differed significantly. 2: Meta-regression implicated that as the age or proportion of CAD increased, TAVI was more advantageous in reducing mortality.
Late all-cause mortality in TAVI was comparable to SAVR. However, the all-cause mortality of RCT and PSM studies differed significantly. Siontis et al. reported 13% relative risk reduction in mortality [
Transcatheter aortic valve implantation vs. surgical aortic valve replacement for treatment of severe aortic stenosis: a meta-analysis of randomized trials.
Two-year outcomes in patients with severe aortic valve stenosis randomized to transcatheter versus surgical aortic valve replacement: the all-comers Nordic aortic valve intervention randomized clinical trial.
]. Another recent meta-analysis by Siemieniuk et al. focused mainly on the outcomes of low-intermediate surgical risk cohorts for aortic valve replacement [
Transcatheter versus surgical aortic valve replacement in patients with severe aortic stenosis at low and intermediate risk: systematic review and meta-analysis.
Two-year outcomes in patients with severe aortic valve stenosis randomized to transcatheter versus surgical aortic valve replacement: the all-comers Nordic aortic valve intervention randomized clinical trial.
]. We have included the data of longest follow-up duration in order to assess the late-mortality. This is the reason for discrepancy from previous meta-analysis and what makes our results unique and important. TAVI patients included in the RCT generally have more strict inclusion/exclusion criteria than the real world practice where patient candidacy for TAVI is decided by the “heart team” and would likely be one of the main reasons for the discrepancy. There were some clinical features set for exclusion criteria in the RCTs but not in the PSM studies. Severe renal insufficiency and/or chronic dialysis patients, patients with a pre-existing prosthetic heart valve, prior cardiac surgery were excluded from the included RCTs [
5-year outcomes of transcatheter aortic valve replacement or surgical aortic valve replacement for high surgical risk patients with aortic stenosis (PARTNER 1): a randomised controlled trial.
Two-year outcomes in patients with severe aortic valve stenosis randomized to transcatheter versus surgical aortic valve replacement: the all-comers Nordic aortic valve intervention randomized clinical trial.
] These clinical features were often included in the PSM studies included in this meta-analysis and also may account for the difference observed between RCT and PSM subgroup meta-analysis. Outcome of TAVI is known to improve with operator/center experience. Several data suggest that roughly 30–80 cases of experiences were required to achieve better outcomes [
]. Most of the centers included in the analysis were large volume, highly experienced centers in both TAVI and SAVR. TAVI has increased not only the volume of SAVR but also led to improved outcomes [
] with the largest weight in favor of TAVI was removed, the pooled HR became significant. The authors have considered the favorable outcome in TAVI to low peri-procedural complications, lower patient-prosthesis mismatch and better improvement in health status. Also, patients with a pre-existing prosthetic heart valve, which could negatively affect TAVI outcomes [
Our meta-regression results suggest that the follow-up duration did not affect mortality of TAVI compared to SAVR. This implies that the follow-up duration did not affect the mortality and TAVI could confer similar long-term mortality compared to SAVR. However, the data for long-term valve durability is still limited for the transcatheter prosthetic valves and further longer follow-up duration could affect the outcomes, although the available data up to 5 years shows similar or even better valve performance than bioprostheses of SAVR [
5-year outcomes of transcatheter aortic valve replacement or surgical aortic valve replacement for high surgical risk patients with aortic stenosis (PARTNER 1): a randomised controlled trial.
Recently, a meta-analysis by Gargiulo et al. reported long-term outcomes in TAVI versus SAVR. They defined long-term mortality as >1 year and used OR to summarize and compare the effect size of TAVI and SAVR for long-term mortality. They reported OR 1.03 and 95%CI 0.65–1.62 for the meta-analysis of RCTs, OR 1.70 and 95%CI 1.23–2.35 for PSM cohort studies and OR 1.28 with 95%CI 0.97–1.69 for the total study included [
]. Our study used HR, which better assess, especially outcomes for long-term mortality, and resulted in more narrow 95%CI. In addition, heterogeneity for the meta-analysis for RCT in our study was non-significant as opposed to result by Gargiulo et al. However, the result was the same for both meta-analysis of RCT, PSM, and both study design combined.
Assessment of long-term outcomes in TAVI is crucial to further expand the indication of TAVI to low surgical risk patients as these patients would have longer life expectancy. The Nordic Aortic Valve Intervention (NOTION) trial included patients at low risk and mean surgical risk was lower than the previous RCTs but the 2-year all-cause mortality was similar between TAVI and SAVR [
Two-year outcomes in patients with severe aortic valve stenosis randomized to transcatheter versus surgical aortic valve replacement: the all-comers Nordic aortic valve intervention randomized clinical trial.
Two-year outcomes in patients with severe aortic valve stenosis randomized to transcatheter versus surgical aortic valve replacement: the all-comers Nordic aortic valve intervention randomized clinical trial.
]. However, Rosato et al. reported worse mortality and the higher rate of major cardiac and cerebrovascular events in TAVI compared to SAVR in patients with EuroSCORE II < 4% [
]. Their study did not exclude subjects on dialysis therapy, history of cardiac surgery and prior stroke and that may have led to the difference from the results of NOTION trial.
Valve durability is another issue that requires long-term follow-up data. Gulino et al. reported that there was 4.6% of progression of paravalvular regurgitation from mild to moderate and 3.2% developed prosthetic valve failure (moderate/severe restenosis, endocarditis with severe intraprosthetic aortic regurgitation and moderate transvalvular regurgitation) during 4-year follow-up with the CoreValve [
]. Others reported durability on the Sapien valve. Mack et al. demonstrated similar mean valve area and mean gradient between TAVI and SAVR over 5-years follow-up. In addition, there was no case that required surgical intervention for valve deterioration in both groups [
5-year outcomes of transcatheter aortic valve replacement or surgical aortic valve replacement for high surgical risk patients with aortic stenosis (PARTNER 1): a randomised controlled trial.
]. Although these results appear promising, bioprosthesis used for SAVR have longer durability experience. Bourguignon and colleagues reported 19.7 years of expected valve durability with the Carpentier-Edwards Perimount pericardial bioprosthesis [
Meta-regression implicated that increased age and co-existing CAD may be associated with more advantageous effects of TAVI relative to SAVR on reducing late mortality. Considering the less invasiveness of TAVI over SAVR, especially the transfemoral approach, it is understandable that TAVI could be more advantageous than SAVR in higher-age patients. Age has been reported to be associated with worse outcomes in both TAVI and SAVR [
Long-term outcomes after transcatheter aortic valve replacement in high-risk patients with severe aortic stenosis: the U.K. Transcatheter Aortic Valve Implantation Registry.
Outcome of patients aged ≥80 years undergoing combined aortic valve replacement and coronary artery bypass grafting: a systematic review and meta-analysis of 40 studies.
5-year outcomes of transcatheter aortic valve replacement or surgical aortic valve replacement for high surgical risk patients with aortic stenosis (PARTNER 1): a randomised controlled trial.
Two-year outcomes in patients with severe aortic valve stenosis randomized to transcatheter versus surgical aortic valve replacement: the all-comers Nordic aortic valve intervention randomized clinical trial.
]. This discordance may be partially explained by the difference statistical methods utilized. Also, there could be a difference in other comorbidities between TAVI and SAVR in these older patients because it is an ad-hoc analysis. Few studies have suggested comparable outcomes of TAVI in nonagenarian patients [
Transcatheter aortic valve implantation in the United Kingdom: temporal trends, predictors of outcome, and 6-year follow-up: a report from the UK Transcatheter Aortic Valve Implantation (TAVI) Registry, 2007 to 2012.
Transcatheter aortic valve replacement versus surgical aortic valve replacement in patients with previous coronary artery bypass surgery: a systematic review and meta-analysis.
]. Although our meta-regression analysis suggests that TAVI may be more effective than SAVR in CAD patients with severe AS, heterogeneity of the definition of CAD and lack of information of the peri-operative revascularization make this result hard to interpret. Therefore, this result should be considered hypothesis generating and confirmed in future studies.
Our results should be viewed in with several limitations. First, not all the studies included were RCT and the result of the meta-analysis of RCT and PSM differed significantly. This is likely due to the difference in patient selection between RCT and PSM, which more reflects the “real world” practice. This finding may be utilized to improve the outcomes in TAVI compared to SAVR. Although we only included PSM studies as non-randomized studies, PSM studies are more susceptible to confounders and biases. Indeed, there were several differences in baseline comorbidities between TAVI and SAVR cohorts, which may have potentially affected the result. However, the numbers of studies with difference in baseline characteristics were limited. Therefore, our results should be viewed with caution. Meta-regression results are exploratory and the results should be viewed with caution. Second, only 4 RCT were included for other clinical outcomes besides all-cause mortality, hence the results may not be robust to conclude the findings. Third, although relevant articles were searched rigorously and strict inclusion/exclusion criteria were defined, publication bias could not be completely excluded. However, there was no evidence of publication bias on Egger's test. Forth, data on late cardiovascular mortality, stroke and myocardial infarction were available only from the RCTs and therefore 4 studies were included. However, there was no significant heterogeneity and sensitivity analysis showed consistent result, suggesting robust result.
Lastly, the only maximum of 5 years has been assessed for the follow-up duration and longer TAVI valve durability needs to be observed.
5. Conclusions
In this meta-analysis, TAVR was associated with similar late all-cause mortality compared to SAVR in the RCT but had worse all-cause mortality in a meta-analysis from PMS. Exploratory meta-regression suggested that with an increase in age and proportion of CAD, TAVI may be a better mode of aortic valve replacement for severe AS. These findings need to be confirmed with further studies.
Disclosure
Authors have no disclosures.
Conflict of interest statement
All authors have no conflict of interest to disclose.
Acknowledgements
To my wife and daughter for giving me pleasure every day.
References
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Percutaneous transcatheter implantation of an aortic valve prosthesis for calcific aortic stenosis: first human case description.
Long-term outcomes after transcatheter aortic valve replacement in high-risk patients with severe aortic stenosis: the U.K. Transcatheter Aortic Valve Implantation Registry.
5-year outcomes of transcatheter aortic valve replacement or surgical aortic valve replacement for high surgical risk patients with aortic stenosis (PARTNER 1): a randomised controlled trial.
in: Higgins J.P. Green S. Cochrane handbook for systematic reviews of interventions version 5.1.0. The Cochrane Collaboration. 2011 ([updated March 2011, Chapter 9, Available from: www.cochrane-handbook.org])
Transcatheter aortic valve implantation vs. surgical aortic valve replacement for treatment of severe aortic stenosis: a meta-analysis of randomized trials.
Transcatheter versus surgical aortic valve replacement in patients with severe aortic stenosis at low and intermediate risk: systematic review and meta-analysis.
ALICE (All-Literature Investigation of Cardiovascular Evidence) Group
Worse survival after transcatheter aortic valve implantation than surgical aortic valve replacement: a meta-analysis of observational studies with a propensity-score analysis.
A prospective, randomised trial of transapical transcatheter aortic valve implantation vs. surgical aortic valve replacement in operable elderly patients with aortic stenosis: the STACCATO trial.
Transcatheter versus surgical aortic valve replacement in patients with severe aortic valve stenosis: 1-year results from the all-comers NOTION randomized clinical trial.
Meta-analysis of observational studies in epidemiology: a proposal for reporting. Meta-analysis of Observational Studies in Epidemiology (MOOSE) group.
Two-year outcomes in patients with severe aortic valve stenosis randomized to transcatheter versus surgical aortic valve replacement: the all-comers Nordic aortic valve intervention randomized clinical trial.
Early and midterm outcome of propensity-matched intermediate-risk patients aged ≥80 years with aortic stenosis undergoing surgical or transcatheter aortic valve replacement (from the Italian Multicenter OBSERVANT Study).
A comparison of conventional surgery, transcatheter aortic valve replacement, and sutureless valves in “real-world” patients with aortic stenosis and intermediate- to high-risk profile.
Propensity matched analysis of longterm outcomes following transcatheter based aortic valve implantation versus classic aortic valve replacement in patients with previous cardiac surgery.
A comparison of transcatheter aortic valve implantation and surgical aortic valve replacement in 1,141 patients with severe symptomatic aortic stenosis and less than high risk.
Transapical transcatheter aortic valve implantation vs conventional aortic valve replacement in high-risk patients with previous cardiac surgery: a propensity-score analysis.
Outcome of patients aged ≥80 years undergoing combined aortic valve replacement and coronary artery bypass grafting: a systematic review and meta-analysis of 40 studies.
Transcatheter aortic valve implantation in the United Kingdom: temporal trends, predictors of outcome, and 6-year follow-up: a report from the UK Transcatheter Aortic Valve Implantation (TAVI) Registry, 2007 to 2012.
Transcatheter aortic valve replacement versus surgical aortic valve replacement in patients with previous coronary artery bypass surgery: a systematic review and meta-analysis.
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