Stent thrombosis: evidence from a network meta-analysis Giuseppe Biondi Zoccai, MD Department of Medico-Surgical Sciences and Biotechnologies Sapienza University of Rome

LEARNING GOALS What is stent thrombosis (ST)? What are network meta-analyses (NMA)? NMA of ST – Goals – Methods – Results – Implications

LEARNING GOALS What is stent thrombosis (ST)? What are network meta-analyses (NMA)? NMA of ST – Goals – Methods – Results – Implications

WHAT IS STENT THROMBOSIS D’Ascenzo et al, submitted

DEFINITIONS OF STENT THROMBOSIS Cutlip et al, Circulation 2007

DEFINITIONS OF STENT THROMBOSIS Cutlip et al, Circulation 2007

DEFINITIONS OF STENT THROMBOSIS Cutlip et al, Circulation 2007

TIMING OF STENT THROMBOSIS Cutlip et al, Circulation 2007

totalacutesubacutelate very late INCIDENCE OF DES THROMBOSIS D’Ascenzo et al, Int J Cardiol 2012

PREDICTORS OF STENT THROMBOSIS D’Ascenzo et al, Int J Cardiol 2011

IMPACT OF STENT THROMBOSIS Chechi et al, J Am Coll Cardiol 2008

LEARNING GOALS What is stent thrombosis (ST)? What are network meta-analyses (NMA)? NMA of ST – Goals – Methods – Results – Implications

FAMOUS QUOTES “If I have seen further it is by standing on the shoulders of giants” Isaac Newton “The great advances in science usually result from new tools rather than from new doctrines” Freeman Dyson

FAMOUS QUOTES “I like to think of the meta- analytic process as similar to being in a helicopter. On the ground individual trees are visible with high resolution. This resolution diminishes as the helicopter rises, and in its place we begin to see patterns not visible from the ground” Ingram Olkin

BABY STEPS OF META-ANALYSIS Karl Pearson (UK): correlation between inoculation of vaccine for typhoid fever and mortality across apparently conflicting studies 1931 – Leonard Tippet (UK): comparison of differences between and within farming techniques on agricultural yield adjusting for sample size across several studies 1937 – William Cochran (UK): combination of effect sizes across different studies of medical treatments 1970s – Robert Rosenthal and Gene Glass (USA), Archie Cochrane (UK): combination of effect sizes across different studies of, respectively, educational and psychological treatments 1980s – exponential development/use of meta-analytic methods

MINIMAL GLOSSARY Review: viewpoint on a subject quoting different primary authors Overview: as above Qualitative review: deliberately avoids a systematic approach Systematic review: deliberately uses a systematic approach to study search, selection, abstraction, appraisal and pooling Quantitative review: uses quantitative methods to appraise or synthesize data Meta-analysis: uses specific statistical methods for data pooling and/or exploratory analysis Individual patient data meta-analysis: uses specific stastistical methods for data pooling or subgroup exploration exploiting individual patient data →Our focus: systematic review + meta-analysis

SYSTEMATIC REVIEW AND META-ANALYSES What is a systematic review? –A systematic appraisal of the methodological quality, clinical relevance and consistency of published evidence on a specific clinical topic in order to provide clear suggestions for a specific healthcare problem What is a meta-analysis? –A quantitative synthesis that, preserving the identity of individual studies, tries to provide an estimate of the overall effect of an intervention, exposure, or diagnostic strategy

EBM HIERARCHY OF EVIDENCE 1.N of 1 randomized controlled trial 2.Systematic reviews of homogeneous randomized trials 3.Single (large) randomized trial 4.Systematic review of homogeneous observational studies addressing patient-important outcomes 5.Single observational study addressing patient-important outcomes 6.Physiologic studies (eg blood pressure, cardiac output, exercise capacity, bone density, and so forth) 7.Unsystematic clinical observations Guyatt and Rennie, Users’ guide to the medical literature, 2002

PROS Application to any clinical research question Systematic searches for clinical evidence Explicit and standardized methods for search and selection of evidence sources Thorough appraisal of the internal validity of primary studies Quantitative synthesis with increased statistical power Increased external validity by appraising the effect of an intervention (exposure) across different settings Test subgroup hypotheses (eg with patient-level reviews) Explore clinical and statistical heterogeneity Lau et al, Lancet 1998

REASONS FOR META-ANALYSIS FAILURE Duplicate efforts may lead to discordant results Funding or conflicts of interest may bias Studies/events might not be found Studies may be of low quality/internal validity Studies may be heterogeneous/inconsistent, ie “mixing apples with oranges” provides unreal fruits Studies may not be relevant to current individual practice Selection based on publication may bias Analysis with highly sensitive but unrobust tests may bias LeLorier et al, New Engl J Med 1997; Lau et al, Lancet 1998; Rosen, BMC BMC Health Services Research 2009

ARGUABLY THE MOST IMPORTANT META-ANALYSIS EVER…. Antman et al, JAMA 1992

…SHOWING DISCREPANCIES AMONG EVIDENCE AND EXPERTS

Hsia et al, Ann Surg 2008 P for effect Incosistency P for heterogeneity STANDARD (PAIR-WISE) META-ANALYSES

INDIRECT AND NETWORK META-ANALYSES Biondi-Zoccai et al, HSR Proceedings 2011

PARALLEL HIERARCHY OF CLINICAL RESEARCH

LEARNING GOALS What is stent thrombosis (ST)? What are network meta-analyses (NMA)? NMA of ST – Goals – Methods – Results – Implications

NETWORK META-ANALYSIS (NMA) OF STENT THROMBOSIS (ST)

NMA OF ST: BACKGROUND

NMA OF ST: GOALS

LEARNING GOALS What is stent thrombosis (ST)? What are network meta-analyses (NMA)? NMA of ST – Goals – Methods – Results – Implications

NMA OF ST: DESIGN

NMA OF ST: DESIGN

NMA OF ST: SEARCH AND SELECTION

NMA OF ST: ANALYSIS

NMA OF ST: ANALYSIS

LEARNING GOALS What is stent thrombosis (ST)? What are network meta-analyses (NMA)? NMA of ST – Goals – Methods – Results – Implications

NMA OF ST: PROFILE FDA approved stents (BMS, SES, PES, End-ZES, Res-ZES, CoCr-EES, PtCr-EES) 49 RCTs 50,844 pts 2602 potentially relevant articles 2441 excluded 2117 not a comparison of DES 324 post-hoc, subgroup, follow-up, or pooled analyses Review of title and abstract 161 articles needing full review 112 excluded 84 not an RCT 13 DES not FDA approved 11 no ARC definition 4 DES pooled Full-text review 49 articles meeting criteria

NMA OF ST: NETWORK 9 studies PES BMS SES End-ZES Res-ZESPt-Cr-EES CoCr-EES 1 study 8 studies 1 study 4 studies 9 studies 6 studies 2 studies 5 studies

NMA OF ST: RESULTS Odds Ratio [95%] 30-day definite stent thrombosis CoCr-EES vs BMS CoCr-EES vs PES CoCr-EES vs SES CoCr-EES vs End-ZES CoCr-EES vs Res-ZES PtCr-EES vs BMS PtCr-EES vs PES PtCr-EES vs End-ZES PtCr-EES vs Res-ZES SES vs BMS 0.21 ( ) 0.27 ( ) 0.40 ( ) 0.22 ( ) 0.07 ( ) 0.06 ( ) 0.07 ( ) 0.06 ( ) 0.02 ( ) 0.54 ( ) Favors Stent Favors Stent 2

NMA OF ST: RESULTS Odds Ratio [95%] 30d – 1yr definite stent thrombosis CoCr-EES vs BMS CoCr-EES vs PES CoCr-EES vs End-ZES End-ZES vs SES 0.27 ( ) 0.24 ( ) 0.13 ( ) 4.06 ( ) Favors Stent Favors Stent 2

NMA OF ST: RESULTS Odds Ratio [95%] 1-year definite stent thrombosis CoCr-EES vs BMS CoCr-EES vs PES CoCr-EES vs SES CoCr-EES vs Res-ZES CoCr-EES vs End-ZES SES vs BMS End-ZES vs SES 0.23 ( ) 0.28 ( ) 0.41 ( ) 0.14 ( ) 0.21 ( ) 0.57 ( ) 1.92 ( ) Favors Stent 1Favors Stent

NMA OF ST: RESULTS Odds Ratio [95%] 2-year definite stent thrombosis CoCr-EES vs BMS CoCr-EES vs PES 0.35 ( ) 0.34 ( ) Favors Stent Favors Stent 2

NMA OF ST: RESULTS

NMA OF ST: RESULTS

NMA OF ST: RESULTS

NMA OF ST: RESULTS IV = inverse variance SE = standard error Odds Ratio IV Random, 95% CI Favors CoCr-EESFavors BMS Weight SE Log (odds ratio) Definite stent thrombosis Direct estimate Indirect estimate Total (95% CI) Test for overall effect Z=4.82 (p< ) Definite or probable thrombosis Direct estimate Indirect estimate Total (95% CI) Test for overall effect Z=4.48 (p< ) % 67.6% % 39.4% 60.6% % 0.24 ( ) 0.24 ( ) 0.24 ( ) 0.38 ( ) 0.33 ( ) 0.35 ( ) Statistical inconsistency (I 2 ): 0% for both comparisons

POTENTIAL OF EVEROLIMUS-ELUTING STENTS Verheye et al, J Am Coll Cardiol 2007

POTENTIAL OF EVEROLIMUS-ELUTING STENTS Kolandaivelu et al, Circulation 2011

LEARNING GOALS What is stent thrombosis (ST)? What are network meta-analyses (NMA)? NMA of ST – Goals – Methods – Results – Implications

IMPLICATIONS The largest and most comprehensive study comparing the rates of ARC definite and definite or probable stent thrombosis between different types of DES and between DES and BMS has the following implications: – CoCr-EES were associated with significantly lower rates of 1-year and 2-year definite stent thrombosis than were BMS, a result not present with other DES.

IMPLICATIONS – The reduction in stent thrombosis with CoCr-EES compared with BMS was apparent both early and late (occurring before 30 days and between 31 days and 1 year). – CoCr-EES were also associated with significantly lower 1-year rates of definite stent thrombosis than were other first and second generation DES, including PES, SES, PC-ZES, and Re-ZES.

IS THIS A PARADIGM SHIFT?

THE REPLY IS YOURS… IF YOU NEEDED A STENT TODAY, WHICH STENT WOULD YOU CHOOSE?

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