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Logo of bmcmedicineBioMed Centralsearchsubmit a manuscriptregisterthis articleBMC Medicine
BMC Med. 2012; 10: 62.
Published online Jun 21, 2012. doi:  10.1186/1741-7015-10-62
PMCID: PMC3386894
Coronary collaterals and risk for restenosis after percutaneous coronary interventions: a meta-analysis
Pascal Meier,corresponding author#1 Andreas Indermuehle,#2 Bertram Pitt,3 Tobias Traupe,4 Stefano F de Marchi,5 Tom Crake,1 Guido Knapp,6 Alexandra J Lansky,7 and Christian Seiler4
1The Heart Hospital London, University College London Hospital Trust, London, UK
2St Thomas' Hospital, Department of Cardiology, King's College London, UK
3University of Michigan Medical Center, Department of Cardiology, Ann Arbor, MI, USA
4University Hospital Bern, Department of Cardiology, Bern, Switzerland
5University of Oslo, Department of Cardiology, Oslo, Norway
6TU University Dortmund, Department of Statistics, Dortmund, Germany
7Yale University Medical Center, Department of Cardiology, New Haven, CT, USA
corresponding authorCorresponding author.
#Contributed equally.
Pascal Meier: pascalmeier74/at/; Andreas Indermuehle: andreas.indermuehle/at/; Bertram Pitt: bpitt/at/; Tobias Traupe: tobias.traupe/at/; Stefano F de Marchi: stefano.demarchi/at/; Tom Crake: tom.crake/at/; Guido Knapp: guido.knapp/at/; Alexandra J Lansky: alexandra.lansky/at/; Christian Seiler: christian.seiler/at/
Received August 17, 2011; Accepted June 21, 2012.
The benefit of the coronary collateral circulation (natural bypass network) on survival is well established. However, data derived from smaller studies indicates that coronary collaterals may increase the risk for restenosis after percutaneous coronary interventions. The purpose of this systematic review and meta-analysis of observational studies was to explore the impact of the collateral circulation on the risk for restenosis.
We searched the MEDLINE, EMBASE and ISI Web of Science databases (2001 to 15 July 2011). Random effects models were used to calculate summary risk ratios (RR) for restenosis. The primary endpoint was angiographic restenosis > 50%.
A total of 7 studies enrolling 1,425 subjects were integrated in this analysis. On average across studies, the presence of a good collateralization was predictive for restenosis (risk ratio (RR) 1.40 (95% CI 1.09 to 1.80); P = 0.009). This risk ratio was consistent in the subgroup analyses where collateralization was assessed with intracoronary pressure measurements (RR 1.37 (95% CI 1.03 to 1.83); P = 0.038) versus visual assessment (RR 1.41 (95% CI 1.00 to 1.99); P = 0.049). For the subgroup of patients with stable coronary artery disease (CAD), the RR for restenosis with 'good collaterals' was 1.64 (95% CI 1.14 to 2.35) compared to 'poor collaterals' (P = 0.008). For patients with acute myocardial infarction, however, the RR for restenosis with 'good collateralization' was only 1.23 (95% CI 0.89 to 1.69); P = 0.212.
The risk of restenosis after percutaneous coronary intervention (PCI) is increased in patients with good coronary collateralization. Assessment of the coronary collateral circulation before PCI may be useful for risk stratification and for the choice of antiproliferative measures (drug-eluting stent instead bare-metal stent, cilostazol).
Keywords: coronary collateral circulation, meta-analysis, restenosis, therapy failure
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