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Published on: September 15, 2023
Aspirin resistance in off-pump coronary artery bypass grafting
Zanxin Wang1, Fei Gao, Jianlong Men
1Department of Cardiovascular Surgery, Tianjin Medical University General Hospital, Tianjin, PR China.
Insights
Aspirin resistance, the inability of aspirin to prevent clots, is transient in about 30% of patients after off-pump coronary artery bypass grafting (OPCAB). Most patients become sensitive to aspirin within six months post-surgery.
Area of Science:
- Cardiovascular Surgery
- Pharmacology
- Thrombosis Research
Background:
- Aspirin is crucial post-coronary artery bypass grafting (CABG).
- Aspirin resistance can be a clinical or laboratory phenomenon.
- Off-pump CABG (OPCAB) may influence aspirin efficacy due to reduced platelet activation.
Purpose of the Study:
- To assess aspirin efficacy in OPCAB patients.
- To determine the incidence of aspirin resistance after OPCAB.
- To compare aspirin response in OPCAB versus medical therapy for ischemic heart disease.
Main Methods:
- 331 patients studied: 111 OPCAB, 220 medical therapy controls.
- Measured arachidonic acid-induced platelet aggregation and urinary 11-dehydro thromboxane B2 (11-dehydroTxB2).
- Assessments were done at baseline and on days 1, 4, and 10 post-treatment; 6-month follow-up for aspirin-resistant patients.
Main Results:
- On postoperative day 1, 29.7% of OPCAB patients showed aspirin resistance (AR).
- AR patients had higher platelet aggregation and 11-dehydroTxB2 levels than aspirin-sensitive (AS) patients.
- All AR patients became AS by 6 months; control patients were all aspirin sensitive.
Conclusions:
- Aspirin resistance is a temporary condition in the early postoperative phase for nearly 30% of OPCAB patients.
- Aspirin's effectiveness is generally restored within six months after OPCAB.
- OPCAB patients exhibit a transient aspirin resistance pattern.
Objective:
Anti-platelet therapy with aspirin is the cornerstone of treatment after coronary artery bypass grafting (CABG). Aspirin resistance describes the clinical observation of the inability of aspirin to prevent thrombotic complications or the laboratory phenomenon of absence of the effect of aspirin on platelet inhibition tests. Off-pump CABG (OPCAB) is associated with reduced platelet activation and turnover compared to on-pump surgery which may indicate that aspirin is more effective after OPCAB. Our aim was to evaluate the efficacy of aspirin and incidence of aspirin resistance in patients undergoing OPCAB.
Methods:
A total of 331 patients was recruited, of which 111 underwent primary OPCAB (group A) and 220 controls with ischaemic heart disease received medical therapy. Arachidonic acid-induced platelet aggregation and urinary 11-dehydro thromboxane B2 (11-dehydroTxB2) were measured at baseline and following aspirin administration on days 1, 4 and 10. A 6-month follow-up was completed in patients who developed aspirin resistance.
Results:
On the first postoperative day, 78 patients (70.3%) were aspirin sensitive (AS) and 33 (29.7%) were aspirin resistant (AR). Of the latter, 18 (16.2%) and five (4.5%) patients remained resistant on days 4 and 10, respectively. AR patients had significantly greater platelet aggregation and urinary 11-dehydroTxB2 levels at all time points than those in the AS group. All patients in the AR group were AS by 6 months. All controls were sensitive to aspirin with similar platelet aggregation and 11-dehydroTxB2 to those in the AS group.
Conclusions:
Aspirin resistance is a transient phenomenon during the early postoperative period in approximately 30% of patients undergoing OPCAB.
