Author + information
- Sameer Aroraa,b,
- Jacob Misenheimera,b,
- Paula D. Strasslea,b,
- Arman Qamara,b,
- Matthew Cavendera,b and
- Prashant Kaula,b
Background: Type 2 Myocardial Infarction (MI) is attributed to an imbalance between myocardial oxygen demand and supply leading to myocardial necrosis. In comparison, type 1 MI is caused by plaque rupture and coronary thrombosis. The International Classification of Disease (ICD) coding does not differentiate these MI subtypes and classifies all of them under the general umbrella of Non-ST segment Elevation MI (NSTEMI).
Methods: We conducted a retrospective analysis of 894 consecutive patients discharged with a diagnosis of NSTEMI between July 2013 and June 2014. Type 1 MI was defined as a rise or fall in troponin along with one of the other MI criteria per The Third Universal Definition. Type 2 MI was also defined per the Third Universal Definition with the presence of a condition other than coronary artery disease with potential to cause demand/supply mismatch. Weighted Kaplan-Meier survival curves were used to estimate the 30-day and 1-year risk of mortality.
Results: 724 patients met the inclusion criteria for MI. Overall, 30-day mortality was 11.1% and one-year mortality was 25.8%. 168 patients (23.2%) were classified as type 2 MI and 556 patients (76.8%) as type 1 MI. Compared to type 1 MI, patients with type 2 MI were more likely to be older (age 74 vs. 65, p<0.0001), have chronic kidney disease (28.3% vs. 18.8%, p=0.01), and have lower body mass indexes (26 vs. 29, p<0.0001). Patients with type 2 MI had longer length of stay (8 days vs. 4 days, p<0.0001) and had higher inpatient mortality (13.1% vs. 3.8%, p<0.0001). After weighting for baseline demographics and comorbidities, 30-day mortality was over 3 times higher (22.3% vs. 6.7%; RR 3.34, 95% CI 2.09, 4.94) among patients with type 2 MI compared to patients with type 1 MI, and 1-year mortality was over 2 times higher (43.3% vs. 19.6%; RR 2.21, 95% CI 1.67, 2.88).
Conclusions: Type 2 MI carries a significantly higher risk of mortality than type 1 MI and given that both are classified under the umbrella term “NSTEMI”, the higher mortality rates associated with type 2 MI are likely responsible for the overall high mortality rates of NSTEMI. Type 2 MI should be recognized separately in the ICD coding system, since it may not be appropriate to group these patients with type 1 MIs.
Poster Hall, Hall C
Sunday, March 19, 2017, 9:45 a.m.-10:30 a.m.
Session Title: Unusual Presentations of ACS
Abstract Category: 2. Acute and Stable Ischemic Heart Disease: Clinical
Presentation Number: 1297-317
- 2017 American College of Cardiology Foundation