Percutaneous coronary intervention versus coronary artery bypass grafting: clinical outcomes in multivessel coronary artery disease

Revascularization with percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) is superior to medical management in reducing symptoms and prolonging exercise duration in patients with coronary artery disease (CAD). Ten randomized trials have compared the outcomes in percutaneous and surgically treated patients with multivessel CAD. The purpose of this article was to summarize the results of those trials to make recommendations regarding appropriate revascularization strategy.     

Comparison of percutaneous transluminal coronary angioplasty versus coronary artery bypass grafting for multivessel coronary artery disease.

Percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass grafting (CABG) are both widely performed in the treatment of multivessel coronary artery disease. Little data directly compare the outcomes of patients treated with these 2 techniques. We examined the characteristics and outcomes of 152 patients who underwent multivessel PTCA and 134 patients who had multivessel CABG. Patients who had prior PTCA or CABG were excluded. Baseline characteristics such as age, sex, and prior myocardial infarction were similar in the 2 groups. Ejection fraction was significantly lower in the CABG group (48 +/- 14%) versus the PTCA patients (53 +/- 15%) (p = 0.002). Narrowing distribution when analyzed by major vascular beds (left anterior descending, circumflex and right coronary arteries) as well as by individual arteries was not significantly different between the groups when left main stenosis was excluded. The surgical group received a larger number of bypasses per patient (3.9) when compared with narrowings dilated in the angioplasty group (3.7) (p less than 0.001). The left internal mammary artery was used in 75% of patients as one of the grafts. Angioplasty success was 95% by standard criteria. Over a mean follow-up of 110 weeks for PTCA patients and 134 weeks for CABG patients the occurrence of death was similar (10 and 14%, respectively) as was myocardial infarction (4 and 2%, respectively). However, all other cardiac events including subsequent cardiac catheterization (49 vs 10%), PTCA (30 vs 2%) and CABG (23 vs 2%) occurred significantly more often in the PTCA group (all p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Outcomes of coronary artery bypass grafting versus percutaneous coronary intervention and medical therapy for multivessel disease with and without left ventricular dysfunction

Multiple randomized trials support the treatment of patients with multivessel coronary artery disease (CAD) and relatively normal left ventricular (LV) ejection fraction (EF) by either percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG). However, there has been a paucity of trials in the recent literature that have compared the outcomes of patients with multivessel CAD and low EF who undergo PCI or CABG. This review examines some of the clinical trials and series in this subgroup of patients and also compares the outcome of patients undergoing either procedure in the absence and presence of LV dysfunction. These trials and series support the notion that PCI can be successfully performed in patients with low EF with relatively low mortality, but that CABG is associated with greater freedom from repeat revascularization and from angina or congestive heart failure symptoms. In addition, most of the data published thus far indicate a long-term survival advantage among patients with ventricular dysfunction who have undergone CABG. Further studies, including randomized trials incorporating the evolving techniques of CABG and the recent advances in PCI, will be needed to assess the proper role and outcome of these two interventions.     

Meta-analysis of percutaneous coronary intervention versus coronary artery bypass graft surgery in patients with diabetes and left main and/or multivessel coronary artery disease

The optimal coronary revascularization strategy for patients with diabetes and left main and/or multivessel disease is undetermined. The aim of our study was to evaluate percutaneous coronary intervention (PCI) versus coronary artery bypass graft (CABG) in those patients. We identified 13 articles, published before October 2011, enrolling 6992 patients, whose follow-up period ranged from 1 to 5 years. Patients with PCI had a significant reduction in cerebral vascular attack (CVA) (OR, 0.29; 95 % CI, 0.16–0.51; p < 0.0001, I ² = 0 %) as compared with CABG, whereas there was a fourfold increased risk of repeat revascularization associated with PCI even using drug-eluting stent (OR, 4.44; 95 % CI, 3.42–5.78; Χ² = 4.92, p < 0.00001, I ² = 0 %). The overall mortality (OR, 0.97; 95 % CI, 0.81–1.15; p = 0.70, I ² = 0 %) was comparable between the PCI and CABG. However, in subgroup analysis, the composite outcome (death/myocardial infarction/CVA) was significantly reduced in favor of DES implantation (OR, 0.79; 95 % CI, 0.63–0.99; Χ² = 1.07, p = 0.04, I ² = 0 %). Our study confirmed the cerebral vascular benefits of PCI by significantly reducing CVA risks, and the composite outcome was better in patients undergoing PCI with drug-eluting stent, despite a higher repeat revascularization rate. It poses imperative demands for future prospective randomized studies to define the optimal strategy in patients with diabetes and left main and/or multivessel disease.     

Cost-effectiveness of bypass surgery versus stenting in patients with multivessel coronary artery disease

PURPOSE: To compare the cost-effectiveness of surgical and angioplasty-based coronary artery revascularization techniques, in particular, angioplasty with primary stenting. METHODS: We used data from the Study of Economics and Quality of Life, a substudy of the Bypass Angioplasty Revascularization Investigation (BARI), to measure the outcomes and costs of angioplasty and bypass surgery in patients with multivessel coronary artery disease who had not undergone prior coronary artery revascularization. Using a Markov decision model, we updated the outcomes and costs to reflect technology changes since the time of enrollment in BARI, and projected the lifetime costs and quality-adjusted life-years (QALYs) for the two procedures from the time of initial treatment through death. We accounted for the effects of improved procedural safety and efficiency, and prolonged therapeutic effects of both surgery and stenting. This study was conducted from a societal perspective. RESULTS: Surgical revascularization was less costly and resulted in better outcomes than catheter-based intervention including stenting. It remained the preferred strategy after adjusting the stent outcomes to eliminate the costs and events associated with target lesion restenosis. Among angioplasty-based strategies, primary stent use cost an additional 189,000 US dollars per QALY gained compared with a strategy that reserved stent use for treatment of suboptimal balloon angioplasty results. CONCLUSION: Bypass surgery results in better outcomes than angioplasty in patients with multivessel disease, and at a lower cost.     

Meta-analysis of 14 trials comparing bypass grafting vs drug-eluting stents in diabetic patients with multivessel coronary artery disease

Background and aimClinical trials have reported lower mortality and repeated revascularization rate in diabetic patients treated with coronary artery bypass grafting (CABG) as compared to percutaneous revascularization. However, these studies were conducted in the era of bare-metal stents. Therefore, we performed a meta-analysis to compare CABG to PCI with drug-eluting stents (DES) in diabetic patients with multivessel and/or left main disease.Methods and resultsThe literature was scanned by formal search of electronic databases (Medline, EMBASE, and Cochrane databases), and major international scientific session abstracts from 2000 to 2013. Primary endpoint was mortality. A total of 14 (4 randomized and 10 non-randomized) trials were finally included, with a total of 7072 patients. Up to 5 years follow-up, CABG was associated with a reduction in mortality (7.3% vs 10.4%, OR[95%CI] = 0.65[0.55–0.77], p < 0.0001; phet = 0.00001), with similar results in both RCTs (OR[95%CI] = 0.64[0.50–0.82], p = 0.0005) and NRCTs (OR[95%CI] = 0.75[0.6–0.94)], p = 0.01) (p int = 0.93). A significant relationship was observed between risk profile and benefits in mortality with CABG (p < 0.001). CABG reduced target vessel revascularization (TVR; 5.2% vs 15.7%, OR[95%CI] = 0.30[0.25–0.36], p < 0.00001, p het = 0.02), with a relationship between risk profile and the benefits from CABG as compared to DES (p < 0.0001). CABG was associated with a lower rate of MACCE (14.9% vs 22.9%, OR[95%CI] = 0.59[0.51–0.67], p < 0.00001, p het<0.00001) but higher risk of CVA (3.6% vs 1.4%, OR[95%CI] = 2.34[1.63–3.35], p < 0.00001, p het = 0.71).ConclusionsThe present meta-analysis demonstrates that among diabetic patients with multivessel disease and/or left main disease, CABG provides benefits in mortality and TVR, especially in high-risk patients but it is counterbalanced by a higher risk of stroke. Future trials are certainly needed in the era of new DES and improved antiplatelet therapies.     

Coronary artery bypass surgery versus percutaneous coronary intervention with drug-eluting stent implantation in patients with multivessel coronary disease

BACKGROUND: Drug-eluting stents (DES) constitute a major breakthrough in restenosis prevention after percutaneous coronary intervention (PCI). This study compared the clinical outcomes of PCI using DES versus coronary artery bypass graft (CABG) in patients with multivessel coronary artery disease (MVD) in real-world. METHODS: From January 2003 to December 2004, 466 consecutive patients with MVD underwent revascularization, 235 by PCI with DES and 231 by CABG. The study end-point was the incidence of major adverse cardiovascular events (MACEs) at the first 30 days after procedure and during follow-up. RESULTS: Most preoperative characteristics were similar in the two groups, but left main disease (24.7% vs 2.6%, P<0.001) and three-vessel disease (65% vs 54%, P = 0.02) were more prevalent in CABG group. The number of coronary lesions was also greater in CABG group (3.7 +/- 1.1 vs 3.3 +/- 1.1, P<0.001). Despite higher early morbidity (3.9% vs 0.8%, P = 0.03) associated with CABG, there were no significant differences in composite MACEs at the first 30 days between the two groups. During follow-up (mean 25+/-8 months), the incidence of death, myocardial infarction, or cerebrovascular event was similar in both groups (PCI 6.3% vs CABG 5.6%, P = 0.84). However, bypass surgery still afforded a lower need for repeat revascularization (2.8% vs 10.4%, p = 0.001). Consequently, overall MACE rate (14.5% vs 7.9%, P = 0.03) remained higher after PCI. CONCLUSION: PCI with DES is a safe and feasible alternative to CABG for selected patients with MVD. The reintervention gap was further narrowed in the era of DES. Aside from restenosis, progression of disease needs to receive substantial emphasis.     

Long term outcomes of new generation drug eluting stents versus coronary artery bypass grafting for multivessel and/or left main coronary artery disease. A Bayesian network meta-analysis of randomized controlled trials

BackgroundMost data guiding revascularization of multivessel disease (MVD) and/or left main disease (LMD) favor coronary artery bypass grafting (CABG) over percutaneous coronary intervention (PCI). However, those data are based on trials comparing CABG to bare metal stents (BMS) or old generation drug eluting stents (OG-DES). Hence, it is essential to outcomes of CABG to those of new generation drug eluting stents (NG-DES).MethodsWe searched PUBMED and Cochrane database for trials evaluating revascularization of MVD and/or LMD with CABG and/or PCI. A Bayesian network meta-analysis was performed to calculate odds ratios (OR) and 95% credible intervals (CrI). Primary outcome was major adverse cardiovascular events (MACE) at 3–5 years. Secondary outcomes were mortality, cerebrovascular accidents (CVA), myocardial infarction (MI) and repeat revascularization.ResultsWe included 10 trials with a total of 9287 patients. CABG was associated with lower MACE when compared to BMS or OG-DES. However, MACE was not significantly different between CABG and NG-DES (OR 0.79, CrI 0.45–1.40). Moreover, there were no significant differences between CABG and NG-DES in mortality (OR 0.78, CrI 0.45–1.37), CVA (OR 0.93 CrI 0.35–2.2) or MI (OR 0.6, CrI 0.17–2.0). On the other hand, CABG was associated with lower repeat revascularization (OR 0.55, CrI 0.36–0.84).ConclusionsOur study suggests that NG-DES is an acceptable alternative to CABG in patients with MVD and/or LMD. However, repeat revascularization remains to be lower with CABG than with PCI.     

Multi-vessel versus culprit-vessel and staged percutaneous coronary intervention in STEMI patients with multivessel disease: a meta-analysis of randomized controlled trials

IntroductionPercutaneous coronary intervention (PCI) is preferred in patients with acute ST-elevation myocardial infarction (STEMI). In patients with acute STEMI with multivessel disease (MVD), the guidelines recommend culprit vessel PCI (CV-PCI) in the absence of hemodynamic instability. We performed a meta-analysis of all randomized controlled trials (RCTs) comparing multi-vessel PCI (MV-PCI) with CV-PCI or staged PCI (S-PCI) in patients with acute STEMI and MVD.MethodsPubMed, EMBASE and CENTRAL were searched for publications since inception to December 2013. Random effects model was used to compute summary effects.ResultsFour RCTs (840 patients) were identified. MV-PCI compared to CV-PCI significantly reduced the risks of major adverse cardiac events (MACE)—a composite of MI, revascularization and all-cause mortality (RR: 0.46, 95% CI: 0.35–0.60, P < 0.00001) by reducing the risks of MI (0.35, 0.17–0.71, P = 0.004) and revascularization (0.35, 0.24–0.52, P < 0.00001). The risk of all-cause mortality was not different (0.69, 0.39–1.21, P = 0.19). S-PCI and MV-PCI had similar risks of MACE (0.96, 0.59–1.57, P = 0.87), MI (0.60, 0.20–1.78, P = 0.36), revascularization (0.86, 0.47–1.54, P = 0.60) and all-cause mortality (1.50, 0.44–5.07, P = 0.57).ConclusionsMV-PCI compared to CV-PCI resulted in lower risks of MACE driven by lower MI and revascularization in patients with STEMI and multi-vessel disease.     

Patient preferences for coronary artery bypass graft surgery or percutaneous intervention in multivessel coronary artery disease

Objectives: Determine if patients prefer multivessel percutaneous coronary intervention (mv‐PCI) over coronary artery bypass graft surgery (CABG) for treatment of symptomatic multivessel coronary artery disease (mv‐CAD) despite high 1‐year risk. Background: Patient risk perception and preference for CABG or mv‐PCI to treat medically refractory mv‐CAD are poorly understood. We hypothesize that patients prefer mv‐PCI instead of CABG even when quoted high mv‐PCI risk. Methods: 585 patients and 31 physicians were presented standardized questionnaires with a hypothetical scenario describing chest pain and medically refractory mv‐CAD. CABG or mv‐PCI was presented as treatment options. Risk scenarios included variable 1‐year risks of death, stroke, and repeat procedures for mv‐PCI and fixed risks for CABG. Participants indicated their preference of revascularization method based on the presented risks. We calculated the odds that patients or physicians would favor mv‐PCI over CABG across a range of quoted risks of death, stroke, and repeat procedures. Results: For nearly all quoted risks, patients preferred mv‐PCI over CABG, even when the risk of death was double the risk with CABG or the risk of repeat procedures was more than three times that for CABG (P < 0.0001). Compared to patients, physicians chose mv‐PCI less often than CABG as the risk of death and repeat procedures increased (P < 0.001 and P = 0.004, respectively). Conclusion: Patients favor mv‐PCI over CABG to treat mv‐CAD, even if 1‐year risks of death and repeat procedures far exceed risk with CABG. Physicians are more influenced by actual risk and prefer mv‐PCI less than patients despite similarly quoted 1‐year risks. © 2013 Wiley Periodicals, Inc.     

Comparing mortality between coronary artery bypass grafting and percutaneous coronary intervention with drug-eluting stents in elderly with diabetes and multivessel coronary disease

Coronary artery disease is a critical issue that requires physicians to consider appropriate treatment strategies, especially for elderly people who tend to have several comorbidities, including diabetes mellitus (DM) and multivessel disease (MVD). Several studies have been conducted comparing clinical outcomes between percutaneous coronary intervention (PCI) and coronary artery bypass graft (CABG) in patients with DM and MVD. However, elderly people were excluded in those clinical studies. Therefore, there are no comparisons of clinical outcomes between CABG and PCI in elderly patients with DM and MVD. We compared all-cause mortality between PCI with drug-eluting stents (DES) and CABG in elderly patients with DM and MVD. A total of 483 (PCI; n = 256, CABG; n = 227) patients were analyzed. The median follow-up period was 1356 days (interquartile range of 810–1884). The all-cause mortality rate was not significantly different between CABG and PCI with DES groups. The CABG group had more patients with complex coronary lesions such as three-vessel disease or a left main trunk lesion. Older age, hemodialysis, and reduced LVEF were associated with increased long-term all-cause mortality in a multivariable Cox regression analysis. The rate of all-cause mortality was not significantly different between the PCI and CABG groups in elderly patients with DM and MVD in a single-center study.     

老年多支血管病变患者置入药物洗脱支架与冠状动脉旁路移植术后近远期临床结果

目的:本研究旨在比较老年(年龄≥75岁)稳定性冠心病合并多支血管病变患者行经皮冠状动脉介入治疗(PCI)置入药物洗脱支架(DES)与冠状动脉旁路移植术(CABG)的近远期临床结果。方法:本研究于2003年7月至2006年12月,连续入选年龄≥75岁稳定性冠心病合并多支血管病变患者363例,在我院行PCI置入DES(n=269)或CABG(n=94)治疗。主要终点为24个月时主要不良心脑血管事件(MACCE),次要终点为24个月时全因死亡及非致死性心肌梗死(MI)、脑血管事件和再次血运重建以及全因死亡、非致死性MI和脑血管事件复合终点事件。结果:住院期间,CABG组的病死率(7.4%vs.1.9%,P=0.023)和非致死性MI的发生率(3.2%vs.0,P=0.023),明显高于DES组,CABG组的MACCE的发生率也明显高于DES组(10.6%vs.1.9%,P=0.001)。多因素回归分析结果显示:24个月时,CABG组和DES组的主要终点事件的风险未见明显差异[22.3%vs.15.2%,风险比(HR)=1.62,95%CI 0.63～3.31,P=0.379],两组的全因死亡、心源性死亡、非致死性MI、脑血管事件和再次血运重建的风险也没有明显差异;CABG组全因死亡、非致死性MI和脑血管事件复合终点事件的风险明显高于DES组(19.1%vs.8.2%,HR 3.87,95%CI:1.24～12.37,P=0.009)。结论:本研究提示,与DES相比,CABG可能会增加75岁以上多支血管病变患者的远期全因死亡、非致死性MI和脑血管事件复合终点事件的风险,而未降低再次血运重建和MACCE。     

Meta-analysis of randomized controlled trials on effect of cilostazol on restenosis rates and outcomes after percutaneous coronary intervention

Cilostazol is a generic drug with antiplatelet and antiproliferative effects. It is unclear whether adding cilostazol to standard dual antiplatelet therapy (aspirin and clopidogrel) after percutaneous coronary intervention reduces restenosis and improves the outcomes. We, therefore, conducted a systematic review and meta-analysis. We systematically searched the Cochrane Library, EMBASE, and MEDLINE databases for randomized controlled trials comparing dual antiplatelet therapy with and without cilostazol after percutaneous coronary intervention. The data were pooled using random-effects models and stratified into short-term (1-month), midterm (1- to 12-month), and long-term (≥12-month) follow-up durations. Twelve randomized controlled trials involving 5,655 patients met our inclusion criteria. The addition of cilostazol to dual antiplatelet therapy was not associated with a significant change in target lesion revascularization (TLR) and target vessel revascularization (TVR) at short-term follow-up. However, TLR and TVR were significantly reduced at midterm follow-up (relative risk 0.57, 95% confidence interval 0.39 to 0.84, and relative risk 0.62, 95% confidence interval 0.47 to 0.83, respectively). Data regarding TLR and TVR at long-term follow-up were limited and inconclusive. We did not find a difference in myocardial infarction, mortality, or major bleeding at any follow-up duration. In conclusion, the addition of cilostazol to dual antiplatelet therapy after percutaneous coronary intervention has favorable effects on TLR and TVR at 1 to 12 months, with no differences in adverse outcomes at any follow-up duration.     

无保护左主干病变合并急性冠状动脉综合征介入与手术治疗对比研究

目的:探讨急性冠状动脉综合征(ACS)合并无保护左主干病变患者经桡动脉介入治疗(TRI)与冠状动脉旁路移植术(CABG)二者的疗效。方法:连续入选2008年3月至2010年12月,于北京安贞医院行经桡动脉介入治疗(n=236)或冠状动脉旁路移植术(n=354)的无保护左主干病变合并ACS患者。对于患者的临床基线特征及冠状动脉病变特征纳入倾向性评分模型进行匹配,得到154对患者。结果:平均随访时间27个月。经过倾向性评分模型进行校正,两组患者的基线资料及病变特征无显著差异。结果显示TRI与CABG两组全因病死率(4.5%vs.6.5%;P=0.454)及心肌梗死发生率(5.2%vs.7.8%;P=0.355)并差异无统计学意义。CABG组患者脑卒中发生率显著增加(零vs.2.6%;P=0.044),而TRI组靶血管重建率(TVR)显著增加(13.0%vs.5.2%;P=0.017)。两组患者复合终点(死亡/心肌梗死/靶血管重建),差异无统计学意义(7.1%vs.12.3%;P=0.124)。结论:对于ACS合并无保护左主干病变患者TRI与CABG的临床复合终点事件风险相似,然而尽管应用药物洗脱支架CABG组患者靶血管重建率仍显著低于介入治疗组。     

Minimally invasive coronary artery bypass grafting versus stenting for patients with proximal left anterior descending coronary artery disease

The purpose of this study was to compare the clinical outcomes of stenting and minimally invasive coronary artery bypass grafting (MIDCAB) in patients with proximal left anterior descending (LAD) coronary artery disease. The Patency, Outcome, Economics of Minimally invasive direct coronary bypass (POEM) study demonstrated that MIDCAB had similar safety and long-term efficacy for LAD revascularization compared with conventional coronary artery bypass grafting. Although LAD stenting is superior to conventional balloon angioplasty, whether it is comparable to MIDCAB is not known. We identified a matched population of 429 consecutive patients with 1-vessel disease who underwent elective proximal LAD stenting and compared their clinical outcomes with those of the 152 patients in the MIDCAB group of the POEM study. The in-hospital event rate was similar in both groups, except for a shorter length of hospital stay with LAD stenting compared with MIDCAB (2.68 vs 4.07 days, p <0.0001). At 6-month follow-up, the incidence of death and Q-wave myocardial infarction or that of cerebrovascular accident was not significantly different between these 2 groups. However, target vessel revascularization was significantly higher with LAD stenting than MIDCAB (13.3% vs 6.6%, p = 0.045). In the subgroup of patients without diabetes, all clinical events were similar in both groups, and the benefit of a shorter hospital stay associated with stenting was maintained. Compared with MIDCAB, LAD stenting is associated with higher repeat revascularization rates but offers the advantage of shorter hospitalization. For nondiabetics with proximal LAD disease, stenting may be the revascularization strategy of choice.     

One-stop hybrid coronary revasculartization versus coronary artery bypass grafting and percutaneous coronary intervention for the treatment of multivessel coronary artery disease: 3-year follow-up results from a single institution

Objectives This study sought to compare midterm clinical outcomes of 1-stop hybrid coronary revascularization (HCR) with coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) for the treatment of multivessel coronary artery disease.     

Coronary artery bypass grafting versus percutaneous coronary intervention in patients with noninsulin treated type 2 diabetes mellitus: A meta‐analysis of randomized controlled trials

Background

The outcomes and prognosis of revascularization by either coronary artery bypass grafting (CABG) surgery or percutaneous coronary intervention (PCI) in patients with noninsulin‐treated type 2 diabetes mellitus (NITDM) have not yet been well established.

Methods

Randomized controlled trials (RCTs) were identified by searching Pubmed, EMBASE, and Cochrane library from inception until May 2016. Heterogeneity was evaluated, and the pooled hazard ratio (HR) was calculated by using a fixed‐effect model. A random‐effect model was used when statistically significant heterogeneity was observed (I² ≥ 50%). All data analyses were carried out by using RevMan 5.3 and STATA software 12.0.

Results

A total of 4 RCTs involving 5 studies, consisting of 2270 patients with noninsulin‐treated type 2 diabetes mellitus, were identified. Compared with CABG‐treated patients, PCI‐treated patients had significantly higher all‐cause mortality (HR 1.39; 95% CI 1.01 to 1.91; P = .04), myocardial infarction (HR 2.14; 95% CI 1.40 to 3.27; P = .0004), repeated revascularization (HR 2.52; 95% CI 1.77 to 3.57; P < .00001), and major adverse cardiovascular and cerebrovascular events (HR 1.50; 95% CI 1.20‐1.87; P = .0004). However, PCI was associated with lower incidence of stoke (HR 0.47; 95% CI 0.24 to 0.90; P = .02).

Conclusions

In NITDM patients, our study suggests that CABG surgery is associated with reduced risk of mortality and morbidity, although with increased incidence of stroke compared with percutaneous coronary intervention. The decision if to have percutaneous coronary intervention or CABG surgery should factor the risk for stroke of the patients when considering CABG over percutaneous coronary intervention. Adequately powered RCTs are needed to confirm the results of this meta‐analysis.