Abstract and Introduction
Abstract
Background Application of percutaneous coronary intervention (PCI) in patients with acute coronary syndromes (ACS) is suboptimal in older frail individuals. This study was conducted to verify if background risk is a risk factor for underuse and diminished effectiveness of PCI in older patients.
Methods An observational cohort study was conducted using data from the Acute Myocardial Infarction in Florence 2 registry, including all ACS hospitalised in 1 year in the area of Florence, Italy. Patients aged 75+ years were selected, whose background risk was stratified with the Silver Code (SC), a validated tool predicting mortality based upon administrative data. Multivariable OR for PCI application and HR for 1-year mortality by PCI usage were calculated.
Results In 698 patients (358 women, mean age 83 years), of whom 176 had ST-segment elevation myocardial infarction (STEMI), for each point increase in SC score the odds for application of PCI decreased by 11%, whereas the hazard of 1-year mortality increased by 10%, adjusting for positive and negative predictors. PCI reduced 1-year mortality progressively more with increasing SC, with HR (95% CI) of 0.8 (0.19 to 1.21), 0.41 (0.18 to 0.45), 0.41 (0.23 to 0.74) and 0.26 (0.14 to 0.48) for SC of 0–3, 4–6, 7–10 and 11+.
Conclusions Application of PCI in older ACS patients decreased with increasing background risk. This therapeutic attitude could not be justified by decreasing effectiveness of PCI in more compromised patients: conversely, application of PCI was associated with a long-term survival advantage that increased progressively with background risk, as expressed by SC.
Introduction
Percutaneous coronary intervention (PCI) has remarkably decreased mortality from acute coronary syndromes (ACS) and its favourable effects, observed in randomised clinical trials, have been confirmed in observational studies. Based on this evidence, practice guidelines prescribe PCI as a class I recommendation, at least in ST-segment elevation myocardial infarction (STEMI), with no mention of age as a possible limiting factor. Older persons, in whom ACSs are common and have poorest outcomes, might benefit the most from widespread availability of PCI. Yet, in clinical practice they are frequently denied PCI, to an extent not justified by contraindications or fear of adverse events and in spite of studies demonstrating that the procedure is safe and effective even in late life. It has been demonstrated that comorbidity, a well-known negative predictor of prognosis in STEMI, is independently associated with underuse of PCI, but does not limit its effectiveness: in the Acute Myocardial Infarction in Florence (AMI-Florence) registry study of all cases of STEMI admitted to hospitals in the area of Florence, Italy, in 2000, the reduction of long-term mortality with primary PCI was progressively greater in patients with more severe comorbidity.
In AMI-Florence, PCI was applied to only 58% of STEMI patients admitted within 12 h from symptom onset. In a new wave of the study (AMI-Florence 2), conducted 8 years later and enrolling also cases with non ST-segment elevation myocardial infarction (NSTEMI), the proportion of STEMI patients receiving early PCI increased to 77%. We therefore deemed as important to investigate, using the AMI-Florence 2 database: (1) if advanced age and clinical complexity remain risk factors for a systematic underuse of PCI even with such a substantial expansion of PCI application and (2) how global health status modulates the prognostic advantage of PCI when NSTEMI is the most common form of ACS. Unlike the previous investigation, in the present study, health status was not assessed solely on the basis of comorbidity, but was expressed in terms of background risk of death using the Silver Code (SC), a thoroughly validated prognostic tool that summarises in a numeric score data obtained from administrative archives.