Antiplatelet Therapy (Aspirin & Clopidogrel) in CKD / Dialysis

The Core Challenge: A Double-Edged Sword

• Fuster and Hurst's The Heart, 15th Ed., p. 2153

Aspirin in CKD

• No specific dose adjustment is required in CKD patients
• A meta-analysis of dialysis patients demonstrated a net benefit of aspirin therapy on cardiovascular outcomes
• Standard doses used: 81-162 mg/day for secondary prevention; 160-325 mg for acute MI

Clopidogrel in CKD

• No specific dose adjustment required in CKD
• In the CREDO trial subgroup, clopidogrel benefit at elective PCI was seen only with normal renal function - benefit was attenuated as renal function declined
• In ACS patients, reductions in adverse events with clopidogrel + aspirin (vs aspirin alone) were progressively attenuated as eGFR worsened
• Metabolism: CYP2C19/CYP3A4 to active metabolite; excretion via urine and feces (not renally cleared as active drug)

• Braunwald's Heart Disease, Table 101.1

Dual Antiplatelet Therapy (DAPT) in CKD

• DAPT (aspirin + P2Y12 inhibitor) is recommended for at least 1 year after ACS in the general population
• In CKD, ticagrelor (a more potent P2Y12 inhibitor) showed a 23% reduction in CV death, MI, and stroke vs clopidogrel in the PLATO trial CKD subgroup (n=3,237) - making it preferred over clopidogrel in ACS with CKD
• Paradoxically, clinical use of both ticagrelor and prasugrel decreases as renal function worsens in practice - likely due to clinician concern over bleeding risk outweighing thrombotic benefit

Dialysis-Specific Considerations

• Hemodialysis patients have platelet dysfunction from uremia (impaired platelet aggregation, vWF abnormalities) - this paradoxically increases bleeding risk even as thrombotic risk remains high
• Aspirin is the most studied and has demonstrated cardiovascular outcome benefit in dialysis patients per meta-analysis
• Clopidogrel's benefit is less clear in advanced CKD/dialysis; the CAPRIE subgroup in CKD did not show clear superiority
• AV fistula/graft patency: Some evidence supports antiplatelets for AV graft patency; a 2025 systematic review (PMID: 39801155) examined antithrombotic therapy impact on AV graft patency and bleeding

Summary Table

Practical Guidance

1. Secondary prevention (stable CKD): Low-dose aspirin 81 mg/day is reasonable; weigh GI/bleeding risk vs. CV benefit, especially in older patients or those with prior GI bleeding
2. ACS with CKD: DAPT is indicated - prefer ticagrelor over clopidogrel based on PLATO data; duration typically 12 months
3. Dialysis patients: Aspirin has demonstrated benefit; use with caution given uremic platelet dysfunction and bleeding risk
4. No dose reduction needed for any antiplatelet in CKD, but monitor closely for bleeding
5. Consider PPI co-therapy to reduce GI bleeding risk, especially in dialysis/advanced CKD

Sources: Fuster and Hurst's The Heart 15th Ed., pp. 2153-2154; Braunwald's Heart Disease Table 101.1; PLATO trial CKD subgroup; CREDO trial subgroup analysis

ECG Interpretation - Mr. Ramkumar, 51 yr Male | 15/07/2026, 11:35 AM

Machine Parameters

Diagnoses

1. Sinus Bradycardia (HR 47 bpm)

• Regular sinus rhythm with upright P waves in I, II, aVF - confirmed SA node origin
• Rate 47 bpm = significant bradycardia (normal ≥ 60 bpm)
• Machine auto-diagnosis: 811 - Sinus Bradycardia ✓

2. First-Degree AV Block

• PR interval = 226 ms (prolonged; normal upper limit 200 ms)
• Every P wave is followed by a QRS - so it is NOT second or third degree block
• PR is constant throughout - consistent first-degree block
• Machine auto-diagnosis: 410 - AV Block I ✓

3. No Acute Ischemia

• ST segments are isoelectric in all visible leads
• No pathological T-wave inversions
• No ST elevation or depression
• QTc 395 ms - normal

4. No Bundle Branch Block

• QRS duration 102 ms - narrow (< 120 ms confirms no complete BBB)

Minnesota Code

• 6-3-0 (PR interval prolongation)
• 8-8-8 (rhythm abnormality)
• 5-5-0 (V5) (amplitude criteria)

Clinical Correlation

• Increased vagal tone (most common - athletes, vasovagal, sleep)
• Drug effect - beta-blockers, digoxin, calcium channel blockers, ivabradine, amiodarone (check medication list)
• Inferior MI (past) - the inferior wall supplies the AV node via RCA; check if there are old Q waves in II, III, aVF
• Hypothyroidism, hyperkalemia - metabolic causes
• Degenerative conduction disease (Lev/Lenegre disease)

The first-degree AV block alone does not require treatment, but in combination with symptomatic bradycardia, a 24-hour Holter monitor and echocardiogram would be appropriate next steps.