What are the chances of kidney function improvement in an older adult with a history of cardiovascular disease undergoing ablation for atrial fibrillation (AFib)?

Kidney Function Improvement After Atrial Fibrillation Ablation

Catheter ablation for atrial fibrillation offers a significant chance of kidney function improvement, particularly in patients who maintain sinus rhythm after the procedure, with the greatest benefit seen in those with pre-existing chronic kidney disease stages 2-3B.

Evidence for Renal Function Improvement

The likelihood of kidney function improvement after AF ablation is substantial and well-documented:

• Patients with CKD stage 2 (eGFR 60-89 mL/min/1.73m²) experience an average eGFR increase from 74±9 to 80±23 mL/min/1.73m² at median 115 days post-ablation 1
• Patients with CKD stage 3A (eGFR 45-59 mL/min/1.73m²) show even more dramatic improvement, with eGFR rising from 53±5 to 69±24 mL/min/1.73m² 1
• Patients with CKD stage 3B (eGFR 30-44 mL/min/1.73m²) demonstrate the most substantial gains, with eGFR increasing from 40±4 to 71±28 mL/min/1.73m² 1
• Over 5-year follow-up, AF catheter ablation significantly improves renal function compared to medical therapy alone, with ablation independently associated with improved eGFR (adjusted OR 2.02,95% CI 1.67-2.46) 2

Critical Determinant: Rhythm Control Success

The magnitude of kidney function improvement is directly tied to maintaining sinus rhythm:

• Freedom from AF/atrial tachycardia recurrence after ablation is independently associated with improved 5-year eGFR (adjusted OR 1.44,95% CI 1.01-2.04) 2
• This benefit is particularly pronounced in patients without diabetes mellitus (adjusted OR 1.78,95% CI 1.21-2.63) 2
• Patients with recurrent AF have significantly higher rates of worsening renal function compared to those maintaining sinus rhythm (21.6% versus 8.7% at 5 years) 3
• Recurrent AF is an independent risk factor for worsening renal function (adjusted HR 1.89,95% CI 1.27-2.81) 3

Type of Atrial Fibrillation Matters

Persistent AF patients derive greater renal benefit than paroxysmal AF patients:

• In persistent AF, eGFR improves from 68.7±18.7 to 71.8±18.9 mL/min/1.73m² at 6 months post-ablation 4
• Persistent AF at baseline independently predicts increased eGFR (OR 2.13,95% CI 1.35-3.40) 4
• Urinary albumin-to-creatinine ratio also improves in persistent AF patients (ln-UACR decreases from 3.1±1.6 to 2.8±1.5) 4
• Paroxysmal AF patients show no significant change in these renal markers 4

Mechanism and Clinical Implications

The bidirectional relationship between AF and CKD is well-established in guidelines:

• AF at baseline predicts new renal dysfunction or proteinuria, suggesting a bidirectional relationship between CKD and AF 5
• Among adults with confirmed CKD, incident AF is associated with a 67% increased rate of kidney failure over 5 years 5
• CKD is an independent predictor of stroke/thromboembolism risk in AF patients (RR 1.62,95% CI 1.40-1.87) 5
• Conversely, AF is associated with increased risk of CKD (RR 1.64,95% CI 1.41-1.91) 5

Important Caveats and Pitfalls

Several factors can limit renal improvement or predict worse outcomes:

• Pre-existing diabetes mellitus significantly attenuates the renal benefit of maintaining sinus rhythm after ablation 2
• Patients with more advanced CKD (eGFR 30-59.9 mL/min/1.73m²) have substantially higher AF recurrence rates (46%) compared to those with better renal function (7-12%) 6
• Impaired renal function is associated with increased non-pulmonary vein ectopic beats, which predict worse ablation outcomes 6
• Worsening renal function after ablation strongly predicts adverse clinical outcomes including all-cause death (adjusted HR 3.46) and heart failure hospitalization (adjusted HR 3.67) 3

Procedural Considerations

Catheter ablation is feasible in CKD patients with specific precautions:

• Particular attention must be paid to fluid balance when using irrigated radiofrequency catheters in patients with CKD 5
• Baseline renal dysfunction does not affect AF ablation rhythm outcomes 2
• Atrial fibrosis burden does not differ significantly across CKD stages and does not predict worse outcomes 1

Anticoagulation Management Remains Essential

Successful ablation does not eliminate the need for anticoagulation based on stroke risk:

• Long-term anticoagulation should be based on CHA₂DS₂-VASc thromboembolic risk profile, regardless of whether sinus rhythm has been restored via ablation 7
• Approximately 50% of patients experience AF recurrence at 1 year after cardioversion, and strokes often occur during documented sinus rhythm in paroxysmal AF patients 7