Impact of heart failure on outcome after percutaneous coronary intervention: is it the patient or the intervention?

Abstract

This editorial refers to ‘Impact of concomitant heart failure on outcomes in patients undergoing percutaneous coronary interventions: analysis of the Melbourne Interventional Group registry’ by K.J. Lu et al., published in this issue on page 416–422. The prevalence of heart failure (HF) in Western countries is estimated to be around 4%, increases with age and is estimated to be ~10–20% in patients aged >70 years.1 The majority of patients with HF have coronary artery disease (CAD). The prognosis of ischaemic HF patients remains poor, despite significant improvements in invasive and pharmacological therapies. Myocardial revascularization is often considered in HF patients with ischaemic or dysfunctional, but viable, myocardium. However, the impact of HF on outcome in patients undergoing percutaneous coronary intervention (PCI) or coronary artery bypass grafting has not been studied in detail.1,2 In this issue of the European Journal of Heart Failure, Lu et al.3 performed a specific analysis on the impact of prior HF in patients undergoing PCI for acute coronary syndromes (ACS). A total of 5006 patients, enrolled between 2004 and 2006 in the Melbourne (Victoria, Australia) Interventional Group Registry, were analysed. This analysis provides interesting data on the prevalence and impact of prior HF on outcomes and medication utilization in patients undergoing PCI, especially since limited studies have been performed on this topic. Important data on the prevalence of HF in patients undergoing PCI come from general data registries, such as the United States National Cardiovascular Data Registry (NCDR).4 In patients undergoing PCI between 2004 and 2006 in an NCDR participating medical centre (n= 588 398), the prevalence of prior HF was 10%. These data are supported by several other American and European PCI registries. Unfortunately, there are no accurate data on the incidence and prevalence of HF in Australia.5 Based on overseas findings, it is estimated that at least 300 000 Australians have chronic HF (4% of the general population aged ≥45 years).5 Lu et al. found a prevalence of prior HF of 3.8% in patients undergoing PCI for ACS, which is lower than expected in this patient category. As noted in the limitations section, the variability in prevalence reflects that the clinical diagnosis of HF is difficult to analyse in large-scale registries and that the real prevalence of prior HF is easily under- or over-estimated. No specific data are available about the impact of HF on efficacy in contemporary PCI practice. In the analysis of Lu et al., the group with prior HF had significantly more comorbidity and more complex coronary anatomy. Despite this higher risk at baseline, the initial procedural success rate was high and similar to the non-HF group. Although the authors did not supply long-term efficacy outcome, these success rates indicate that PCI is an effective treatment option for CAD in patients with prior HF. Optimization of PCI strategies and use of new medications could further increase the efficacy of PCI in patients with prior HF. Given the high rate of cardiogenic shock, left main lesions and multivessel disease in patients with prior HF, these patients are also likely to benefit from haemodynamic assist devices during PCI.6 Therefore, it would be interesting to investigate the frequency of usage and impact of intra aortic balloon pump and left ventricular assist devices in these high-risk patients. Regarding the safety of performing PCI in patients with HF, the presence of HF has been associated with a higher incidence of adverse events after PCI. In the analysis of the NCDR, prior HF was an independent uni- and multivariate predictor of 30-day mortality after PCI.4 The analysis of Lu et al. certainly underlines that prior HF is a risk factor for adverse events during hospitalization and follow-up after PCI. However, this is not surprising given the high morbidity and mortality rates associated with HF in general.7 It remains unclear as to what extent the higher adverse event rates were directly related to the PCI procedure. Therefore, adding additional data on, for example, incidences of stent thrombosis, contrast-induced nephropathy or urgent revascularizations might offer some clues about the mechanism of the higher incidence of adverse events. The increased likelihood of adverse events in patients with prior HF may also be caused by an underutilization of pharmacological therapies, as was reported in the analysis of Lu et al.. Evaluation of medication utilization to improve adherence to guidelines is of great importance as a method to improve the quality of health care in patients with ischaemic HF8,9 and is likely to lead to a reduction in mortality.10 Lu et al. observed serious underutilization of proven therapies for HF, for example, beta-blockers were only used in 55% of the patients with prior HF. This is interesting, but unfortunately the authors did not manage to clarify the reasons for medication underutilization. Was the medication not prescribed by the physician, or was the prescribed treatment not followed by the patient, for example, due to non-compliance or side effects?11 In addition, the medication may not have been indicated in some of the patients, as the definition of HF used in the study was limited by the fact that it included any HF and did not stratify to diastolic or systolic HF. Further, the authors did not include an analysis of new onset HF. Including new onset HF is important, because of the high rate of new onset HF as a complication of ACS. These limitations make the present analysis less valuable for drawing firm conclusions and providing advice on medication utilization in HF patients. In conclusion, the study of Lu et al. documents that although patients with prior HF have significantly higher-risk baseline characteristics than non-HF patients, the initial lesion success rate after PCI for ACS is high and similar to non-HF patients. During hospitalization and at 12-month follow-up, the rate of adverse events is significantly higher in patients with prior HF. Optimization of invasive and pharmacological therapies could lower the incidence of adverse events in patients with prior HF.