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
  patients subsequent likelihood of receiving
  secondary prevention antiplatelet therapies after
  hospital discharge

3
Methods
Total AMI Population in PREMIER Registry N2498
In-hospital bleeding or transfusion? (TIMI
major/minor bleeding or non-CABG transfusion
with baseline Hct 28)
yes
no
No Bleeding N 2,197
Bleeding N 301

• Patient Follow-up
• 1 month
• 6 months
• 1 year

4
No Bleeding N 2,197
Bleeding N 301
P-value
Baseline characteristics
Age (yrs) 60.3 12.8 65.1 13.7 lt.001
Women () 31.1 43.2 lt.001
Hypertension () 62.7 70.4 .01
Diabetes mellitus () 28.7 29.6 .76
Prior MI () 21.4 22.3 .73
Prior PCI () 17.8 18.9 .62
Prior CABG () 13.0 12.6 .87
Prior CHF () 11.2 18.3 lt.001
Baseline CrCl (mg/dL) 74.4 29.8 65.6 40.4 lt.001


In-hospital cath 87.2 85.4 .39
In-hospital PCI 61.3 57.8 .24
In-hospital CABG 11.4 12.0 .79
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
1
2
0
Less use
More use
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Antiplatelet Use Stratified by Follow-up Type1
month
Plt0.001
P0.03
Plt0.001
P0.006
Thienopyridine Use at 1 month
Aspirin Use at 1 month
7
Antiplatelet Use Stratified by Follow-up Type6
months
Plt0.001
Plt0.001
Plt0.001
Plt0.001
Thienopyridine Use at 6 months
Aspirin Use at 6 months
8
Antiplatelet Use Stratified by Follow-up Type12
months
Plt0.001
P0.003
Plt0.001
Plt0.001
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

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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

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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.