|Adjunctive devices in primary or rescue PCI: a meta-analysis of randomized trials
|Burzotta F, Testa L, Giannico F, Biondi-Zoccai G G, Trani C, Romagnoli E, Mazzari M, Mongiardo R, Siviglia M, Niccoli G, De Vita M, Porto I, Schiavoni G, Crea F
The authors concluded that adjunctive devices, particularly thrombectomy devices, during mechanical reperfusion in ST-elevation acute myocardial infarction patients, may be associated with reduction of angiographically evident distal embolisation and improved myocardial blush grade <3 rates compared to standard percutaneous coronary interventions. The authors' conclusions reflected the evidence presented and are reliably derived, although some studies might have been missed.
To evaluate the effectiveness of adjunctive devices (AD) with theoretical anti-embolic properties in patients with ST-elevation acute myocardial infarction (STEMI) undergoing percutaneous coronary interventions (PCI).
MEDLINE was searched without language restriction (search dates not reported). Search terms were reported. The literature search was conducted according to a modified strategy described elsewhere (Biondi Zoccai et al, 2005, see Other Publication of Related Interest). TCT, EuroPCR, ACC, AHA and ESC websites were also searched for relevant abstracts or presentations between October 2003 and June 2006.
Randomised controlled trials (RCTs) comparing any AD with standard PCI (SP) in patients with STEMI were eligible for inclusion in the review. Two types of AD were included in the studies; thrombectomy and distal protection. Where stated pre-coronary time limit ranged from <6 to <24 hours and the timing for ST-segment resolution (STR) assessment ranged from immediately after PCI up to 180 minutes. The following post-procedural electrocardiographic and clinical end-points were sought: rate of angiographically-evident distal embolisation; rate of post-PCI thrombolysis in myocardial infarction (TIMI) flow grade <3; rate of post-PCI myocardial blush grade (MBG) <3; rate of failure to achieve STR >70% (or 50% if 70% not available); early (up to 30 days) rate of death or myocardial infarction (MI), including cases of sub-acute stent thrombosis; early (up to 30 days) rate of major adverse coronary and cardiovascular events (MACCE) (i.e. death, MI, target vessel revascularisation, stroke). Selected trials were required to have randomised treatment allocation, intention-to-treat (ITT) analysis, and unequivocal treatment allocation process to be included in the review.
The authors did not state how papers were selected for the review or how many reviewers performed the selection process.
Assessment of study quality
The authors did not state how the validity of the studies was assessed or how many reviewers performed the validity assessment.
Data on a list of pre-specified end-points were extracted. When only percentages were available, the raw number of events was calculated. Definitions of MI compromised Q-wave and non-Q MI were as described by the individual studies. Odds ratio (ORs) and their associated 95% confidence intervals (CI) were calculated for these binary outcomes.
Three reviewers independently extracted data for the included studies. Any disagreements were resolved by consensus.
Methods of synthesis
Studies were pooled in a meta-analysis using both fixed and random effects models for each end-point. However, as significant heterogeneity was found, all presented results are from the random effects model. In order to obtain a two-tailed 'P', a "z" test was carried out. Statistical heterogeneity was assessed using the Cochran Q test and the I2 statistic (values of 25%, 50% and 75% were taken to represent low, moderate and high levels of heterogeneity respectively). Sensitivity analyses were performed, restricting studies published as full papers and mode of action of AD. Publication bias was assessed using a funnel plot for the outcome 'failure to achieve STR', as well as with Egger's test.
Results of the review
Eighteen prospective RCTs (n=3,180) were included in the review; 10 single-centre studies and 8 multi-centre studies.
No study reported angiographic follow-up, and only a minority provided data on six-month follow-up for clinical outcomes. Pooled analyses for these outcomes were not performed.
AD was associated with lower rates of angiographically evident distal embolisation (OR 0.54, 95% CI: 0.37, 0.81) (10 RCTs, n=2,251). Better results for angiographic and electrocardiographic reperfusion were found with AD on MGB<3 (OR 0.53, 0.37, 0.76) (14 RCTs, n=2,744) and absence of STR (OR 0.60, 95% CI: 0.45, 0.78) (17 RCTs, n=3,042). No statistically significant between group difference was found for TIMI<3 (OR 0.76, 95% CI: 0.51, 1.12) (14 RCTs, n=2,614). Evidence of significant heterogeneity was found for all these analyses. No statistically significant between group difference was found for early acute myocardial infarction or death (OR 0.85, 95% CI: 0.54, 1.33) (13 RCTs, n=2,818).
Subgroup analysis, according to type of AD, found a statistically significant effect in favour of treatment with thrombectomy for angiographically evident distal embolism (OR 0.51, 95% CI: 0.28, 0.92) (7 RCTs, n=1,281), absence of STR (OR 0.46, 95% CI: 0.32. 0.66) (12 RCTs, n=1,934) and MGB<3 (OR 0.42, 95% CI: 0.23, 0.75) (9 RCTs, n=1,562). Evidence of significant heterogeneity was found for MGB<3 and not STR. A statistically significant effect of treatment in favour of distal protection was found for MGB<3 (OR 0.72, 95% CI: 0.55, 0.96) (5 RCTs, n=1,182). Similar results were found when analysis was restricted to published papers.
Evidence of publication bias was found on Egger's test (p=0.006) for the end-point post-procedural ST-segment resolution.
AD may be associated with reduced rate of angiographic distal embolism and improved MBG<3 and STR rates compared with SP, although efficacy may differ with the type of device employed. Early clinical outcomes (acute MI or death) were similar between groups. Larger studies are needed to assess the clinical impact of AD.
The review question was supported by broad inclusion criteria. Several sources were used to locate relevant articles without language restriction and the authors attempted to locate unpublished studies. Publication bias was found. Methods used to extract data were likely to minimise the possibility of reviewer error or bias but it is unclear whether similar methods were used to select studies. Aspects on internal validity were assessed as part of the review study selection process and only studies that met pre-specified criteria were included, thus all included studies were deemed to have acceptable quality. Standard statistical methods were used to pool the data and some potential sources of heterogeneity were assessed (type of device). The authors' conclusions reflect the evidence presented and are reliably derived, although some studies might have been missed.
Implications of the review for practice and research
Practice: the authors did not state any implications for practice.
Research: the authors stated that further research into the use and mechanism of AD devices is warranted.
Burzotta F, Testa L, Giannico F, Biondi-Zoccai G G, Trani C, Romagnoli E, Mazzari M, Mongiardo R, Siviglia M, Niccoli G, De Vita M, Porto I, Schiavoni G, Crea F. Adjunctive devices in primary or rescue PCI: a meta-analysis of randomized trials. International Journal of Cardiology 2008; 123(3): 313-321
Other publications of related interest
Biondi Zoccai GG, Agostoni P, et al. A simple hint to improve Robinson and Dickensin's highly sensitive PubMed search strategy for controlled clinical trials. Int J Epidemiology 2005; 34: 224-5.
Subject indexing assigned by NLM
Angioplasty, Balloon, Coronary /instrumentation /methods; Cardiac Catheterization; Coronary Angiography; Coronary Circulation /physiology; Coronary Thrombosis /prevention & control; Electrocardiography; Female; Follow-Up Studies; Humans; Male; Meta-Analysis as Topic; Myocardial Infarction /diagnosis /mortality /therapy; Prospective Studies; Prostheses and Implants; Randomized Controlled Trials as Topic; Risk Assessment; Severity of Illness Index; Stents; Survival Analysis; Treatment Outcome; Vascular Patency
Database entry date
This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.