Antiplatelet Therapy Use after Discharge among Acute Myocardial Infarction Patients with In-hospital Bleeding

1. Antiplatelet Therapy Use after Discharge among Acute Myocardial Infarction Patients with In-hospital Bleeding Tracy Y. Wang, MD, MHS, Lan Xiao, PhD, Karen P. Alexander, MD, Sunil V. Rao, MD, Mikhail N. Kosiborod, MD, John S. Rumsfeld, MD, PhD, John A. Spertus, MD, MPH, and Eric D. Peterson, MD, MPH Wang TY et al, Circulation 2008

2. Background • Antithrombotic therapies are important in the management of patients with acute myocardial infarction (AMI), but incur an increased risk of bleeding complications • Prior studies have established an association between bleeding during AMI and worse short- and long-term outcomes • One potential explanation may be that bleeding during the AMI hospitalization reduces the patient’s subsequent likelihood of receiving secondary prevention antiplatelet therapies after hospital discharge

3. Methods Total AMI Population in PREMIER Registry N=2498 In-hospital bleeding or transfusion? (TIMI major/minor bleeding or non-CABG transfusion with baseline Hct ≥28) yes no Bleeding N = 301 No Bleeding N = 2,197 Patient Follow-up • 1 month • 6 months • 1 year

4. No Bleeding N = 2,197 Bleeding N = 301 P-value Baseline characteristics In-hospital procedures

5. Adjusted Discharge Medication Use Adjusted OR 95% CI † 0.45 0.31 – 0.64 Discharge Aspirin 0.68 0.50 – 0.92 1 month 0.63 0.46 – 0.87 6 months 0.94 0.66 – 1.34 1 year Discharge 0.62 0.42 – 0.91 0.83 0.59 – 1.17 1 month Thienopyridine 1.06 0.78 – 1.45 6 months 1.12 0.81 – 1.55 1 year 0.76 0.54 – 1.08 Discharge 1.05 0.76 – 1.44 1 month Beta-blocker 1.09 0.79 – 1.51 6 months 1 year 0.87 0.63 – 1.20 Discharge 0.81 0.60 – 1.10 1 month Statin 0.65 0.48 – 0.87 6 months 0.80 0.59 – 1.09 0.81 0.58 – 1.12 1 year 0 1 2 Less use More use

6. Antiplatelet Use Stratified by Follow-up Type1 month P<0.001 P=0.03 P<0.001 P=0.006 Thienopyridine Use at 1 month Aspirin Use at 1 month

7. Antiplatelet Use Stratified by Follow-up Type6 months P<0.001 P<0.001 P<0.001 P<0.001 Thienopyridine Use at 6 months Aspirin Use at 6 months

8. Antiplatelet Use Stratified by Follow-up Type12 months P<0.001 P=0.003 P<0.001 P<0.001 Thienopyridine Use at 12 months Aspirin Use at 12 months

9. Limitations • Small sample size limited power to assess how timing of antiplatelet medication resumption influences long-term outcomes • PREMIER did not capture detailed clinical rationale behind medication adjustments after discharge • Outpatient follow-up (type/intensity) was not pre-specified. • Observational analysis subject to unmeasured confounders despite multivariable adjustment

10. Conclusions • A significant proportion (12%) of patients with AMI experience bleeding complications or require non-CABG related transfusions during their AMI hospitalization • Patients who bleed are older and more likely to have comorbidities which can contribute to their worse long-term outcomes • Yet, another explanation for these worse outcomes might be that these patients are less aggressively treated with guidelines-recommended AMI therapies

11. Conclusions • In the setting of a recent bleed, post-AMI patients are less likely to be discharged on antiplatelet therapies such as aspirin or thienopyridines • Clinicians may defer re-initiation until “safe” from further bleeding • However, this treatment gaps persists even up to 6 months after the initial in-hospital event • Patients seen in follow-up by a cardiology specialist are more likely to be treated with antiplatelet agents than those seen in follow-up by a primary care practitioner or those with no clinical follow-up

12. Implications • While the decision to treat AMI patients with antiplatelet medications after bleeding is largely based on clinical intuition, continuity of care is critical as patients without post-discharge follow-up miss the opportunity to be evaluated for possible re-initiation of guidelines recommended secondary prevention therapies. • Clinicians should continuously reassess the opportunity to safely re-initiate these medications after resolution of the bleeding event.