AbstractBackground and aim
Cardiovascular disease is the biggest killer in Wales, with non-ST-elevation acute coronary syndrome (NSTEACS) forming the commonest diagnosis. NSTEACS patients are at risk of death, reinfarction and ischaemia, a risk that increases as cardiovascular risk (GRACE) increases. Standard initial medical therapy followed by the consideration of invasive therapy depending on risk is a proven cost-effective therapy. However, data from national registries suggest that at least 60,000 NSTEACS patients per year do not undergo revascularisation, despite being at high risk. The majority of these patients are elderly and thus high risk (in terms of GRACE score), very few of the trials that shape our guidelines include elderly high risk patients. The aim of our study is to identify factors that influence selection for invasive therapy, and to investigate the consequences on net adverse cardiac outcomes (NACE): adjusted mortality, reinfarction, stroke and significant bleeding.Methods
Using the Secure Anonymized Information Linkage (SAIL) databank, we linked hospital data for all patients admitted to hospitals in South Wales (UK) with a first diagnosis of NSTEACS between 2004–2014. Cohorts of patients undergoing medical versus invasive therapy were identified and validated by a combination of ICD-10 codes, operation codes, and linkage to coronary angiography data. Multivariate analysis was performed to investigate the influence of baseline characteristics on treatment decisions. Propensity matching – for a wide variety of baseline characteristics – was carried out with subsequent Cox regression analysis to show the adjusted effects of invasive therapy versus medical therapy only.Results
There were a total of 57,964 NSTEACS patients in the study period. Of these, 20 421 received invasive therapy and 37 543 received medical therapy only. Medical therapy patients were older (mean age± standard deviation 74.9±13.2 vs 65.0±11.7) and more likely to have cancer, anaemia, dementia, heart failure, chronic lung, liver and kidney disease (p<0.05). Likelihood of undergoing invasive therapy was significantly reduced in patients over the age of 70 (OR 0.62 in 70–80, 0.18 in 80–90, 0.03 in 90+, p<0.05). After propensity matching between cohorts, net adverse cardiac events (mortality, stroke, reinfarction, significant bleeding) were significantly improved for the invasively managed patients in all age groups. Reduction in NACE were much larger in the elderly high risk groups that received invasive therapy.Conclusion
Our study suggests that older higher risk patients have very low rates of invasive therapy but appear to have more to gain from this approach (than younger, lower risk patients), in terms of mortality and morbidity. In the older higher risk population these results suggest that increased frequency of invasive therapy will lead to reduced short (1 year) and long (5 year) term mortality and net adverse cardiac events (NACE).