Looking beyond angioplasty: the importance of left ventricular dysfunction.

The study by Mamas et al. is an observational analysis of 230 464 cases entered into the British Cardiovascular Intervention Society (BCIS) angioplastydatabasefor theyears2006–2011.The influenceof left ventricular ejection fraction (LVEF) on early and late mortality after percutaneous coronary intervention (PCI) was studied. The authors reported a three-fold increase of 30-day mortality after PCI in patients with moderately impaired LVEF (30–49%) and a seven-fold increase in patients with poor LVEF (,30%) when compared with patients with preserved LVEF (≥50%). You may say that it is not such a novel and revolutionary message, but the sheer size of the database, the universal patient inclusion, and the similar findings in an equally large previous US study make the conclusions compelling and widely applicable. Well-conducted large national databases have become a welcome source of scientific information complementing dedicated studies, and their reliability is gradually improving.Datacompletenessof compulsory national databases is one of the parameters used to determine the level of NHS funding to hospitals in the UK, and the outcome data come from the National Institute of Statistics, tracking 100% of patients at least for mortality. It is somewhat annoying that data on LV function were collected in less than half of the almost half million PCIs performed in England, Wales, and Northern Ireland in the study period. You can be sure that this is going to improve in the next iteration of this analysis. Data on operator and hospital mortality coming from this database are now available to the public (www.bcis.org.uk), and quite sophisticated correction parameters ensure that the mortality of operators and hospitals performing more complex procedures in higher risk patients is properly adjusted. Based on this study, I am sure that the BCIS will ask that data on LV function are also introduced among the correction factors, prompting operators to enter the data more consistently. There is another limitation more difficult to overcome, but important to ensure we make the correct changes in our treatment policy to address the problem of a higher mortality in patients with poor LV function. The definition of the cause of death is difficult and reliability is low, even when the individual death certificates are reviewed. In this study no attempt is made to distinguish cardiovascular and non-cardiovascular causes of death, let alone more subtle differences among sudden death, new ischaemic events, cancer, etc. This article tells us that a successful PCI is not sufficient to revert the trend to higher mortality in patients with low LVEF, but does not tell you whether this is correctable and how. Preventable deaths can be caused by an inadequate treatment of heart failure, an insufficient use of implantable cardioverter defibrillators (ICDs), a poor angioplasty technique leading to high incidences of restenosis and stent thrombosis, or an incomplete initial revascularization. Let us focus on the deaths caused by the last two interventional pitfalls that can be potentially prevented by improving the quality of the work done during the initial PCI. The study probably used a mixture of firstand second-generation drug-eluting stents (DESs), with some bare metal stents still used in patients with acute myocardial infarction, as suggested in the old National Institute of Health and Care Excellence (NICE) recommendations for ST-segment elevation myocardial infarcion (STEMI) treatment (www.nice.org.uk/). There is overwhelming evidence from single studies, meta-analyses, and large registries that secondgeneration DESs have a lower thrombosis and restenosis rate than first-generation DESs. 5 Bare metal stents should not be used unless there is an absolute specific indication for a super short period of double antiplatelet treatment because they lead to a much greater risk of restenosis which often manifests itself as a new acute coronary syndrome. There is also a greater early stent thrombosis rate andnodemonstrable advantage for late stent thrombosis when compared with second-generation DESs, and this has been specifically demonstrated in patients with STEMI . –8 Stent thrombosis is higher in the presence of a low EF, and an acute