Abstract 268: Patients >65 Years of Age With Acute Myocardial Infarction Are Less Likely to Undergo Percutaneous Coronary Intervention and Have a Higher In-hospital Mortality
Authors: Rzechorzek Wojciech , Bhatia Kirtipal , Skaf Michel , Lopes Jan , Herzog Eyal 
Published: April 2019

Background:
Studies have shown that patients >65 years of age with ST-elevation myocardial infarction are less likely to undergo a percutaneous coronary intervention (PCI) and are more likely to have a delayed door-to-balloon time above 90 minutes despite proven efficacy in these population. We investigated current outcomes and therapeutic approach in a large unselected population of patients.

Methods:
In a retrospective study, using the 2014 Nationwide Inpatient Sample (NIS), we analyzed patients >65 years of age presenting with acute myocardial infarction (AMI). We performed univariate analysis of age, sex, race, hospital location, hospital teaching status, insurance type, hospital bed size, Charlson Comorbidity Index and other relevant comorbidities and we included variables with p<0.2 in the multivariate logistic regression model.

Results:
A total of 115,042 patients with AMI were identified. Patients >65 years of age (54%) had mean age of 78+/_0.04, vs 55 +/_ 0.04, p<0001 and a higher percentage of them were female (45% vs 30%, p<0.001). Patients >65 years of age were were more likely to have hypertension (78% vs 69%, p<0.001), chronic kidney disease (26% vs 9%, p<0.001), heart failure (0.8% vs 0.5%, p<0.001) and diabetes mellites (32% vs 29%, p<0.001). Patients >65 years of age were less likely to receive a PCI including angioplasty (OR=0.66, 95%CI =0.46-0.94, p<0.02) and stent placement (OR=0.64, 95%CI =0.62-0.67, p<0.001). They also had less timely stent implantation (stent within 48 hours: OR=0.66, 95%CI =0.63-0.68, p<0.001). There was no difference in utilization of thrombolysis and CABG surgeries. Patients >65 years of age with AMI had higher incidence of cardiac arrest (OR=1.21, 95%CI =1.06-1.37, p=0.004) as well as higher in-hospital mortality (OR=2.32, 95%CI =2.11-2.56, p<0.001). There was no difference in implantation of cardioverter-defibrillator. Patients >65 years of age were more likely to have shock (OR=1.28, 95%CI = 1.06-1.54, p-=0.009), heart failure (OR=1.62, 95%CI = 1.54-1.71, p<0.001), and were more likely to require mechanical ventilation (OR=0.15, 95%CI = 1.07-1.25, p<0.001). The use of short-term mechanical circulatory support was similar in patients >65 years of age. Despite increased length of stay in patients >65 years of age (Coef. =0.56, 95% CI= 0.45-0.66, p<0.001), the total charges were smaller (Coef. = -3231$, 95% CI=- 5237$ - -1224$, p=0.002).

Conclusion:
Patients >65 years of age and AMI had worse outcomes and were treated with a different therapeutic approach. They were less likely to be treated with a PCI and receive a timely intervention, which might explain lower total charges. Yet, they had a higher incidence of cardiac arrest and in-hospital mortality as well as higher incidence of shock, heart failure exacerbations and required higher utilization of mechanical ventilation, which could have contributed to the increased length of stay.