Management of Post-Void Residual After Aquablation
Immediate Recommendation
Repeat the PVR measurement 1–2 additional times before making any treatment decision, as a single PVR of 250 mL at 48 hours post-Aquablation does not mandate immediate intervention. 1, 2
This patient's pre-operative PVR ranged from 50–250 mL, demonstrating significant baseline variability, and the current 250 mL reading may simply reflect normal test-retest variation rather than true retention. 1, 3
Why Repeat Measurement is Critical
- PVR measurements show marked intra-individual variability, and basing treatment decisions on a single measurement is a critical pitfall to avoid. 1, 2, 3
- In one study of urogynaecologic patients, the prevalence of PVR ≥100 mL declined from 14% to only 1.3% when measurements were repeated. 3
- Confirm the finding with 2–3 repeat measurements (ideally using ultrasound within 30 minutes of voiding) before committing to any catheterization strategy. 1, 2
- This patient's pre-operative variability (50–250 mL) makes repeat testing even more essential to establish whether 250 mL represents true post-operative dysfunction or normal variation. 1, 4
Expected Post-Aquablation Course
- Failure of initial void trial occurs in 40% of men with pre-operative acute retention and 12.5% with chronic retention (PVR >300 mL), compared to only 7.2% without retention. 5
- This patient's pre-operative PVR of up to 250 mL places them in an intermediate risk category. 5
- Despite initial void trial failures, 98% of men achieve spontaneous voiding by mean 5-month follow-up after Aquablation, regardless of pre-operative urodynamic findings. 5
- The 48-hour timepoint is very early in the recovery process, and transient elevation in PVR is common due to post-operative edema and inflammation. 5
Management Algorithm Based on Repeat PVR Results
If Repeat PVR Measurements Remain >200–250 mL:
- Initiate intermittent catheterization every 4–6 hours to prevent bladder volumes from exceeding 500 mL. 1, 2, 6
- Intermittent catheterization is first-line intervention and dramatically reduces UTI risk compared to indwelling Foley catheters. 1, 2
- Each catheterization volume should be kept <500 mL to maintain physiologic bladder capacity and reduce infection risk. 2, 6
- Implement behavioral modifications: scheduled voiding every 3–4 hours, double-voiding technique (especially morning and night), adequate hydration, and optimized voiding posture. 2, 6
If Repeat PVR Measurements Are <200 mL:
- Continue observation with scheduled voiding every 3–4 hours. 2
- Repeat PVR measurement in 4–6 weeks to assess improvement as post-operative edema resolves. 1, 2
- Monitor for symptoms of incomplete emptying, recurrent UTIs, or worsening voiding function. 2, 6
Critical Pitfalls to Avoid
- Never place an indwelling Foley catheter for convenience when intermittent catheterization is feasible—indwelling catheters dramatically increase UTI risk, particularly beyond 48 hours. 1, 2
- Do not base treatment decisions on a single PVR measurement at 48 hours post-operatively—always confirm with repeat testing given the high test-retest variability and expected post-operative inflammation. 1, 2, 3
- Do not assume this PVR indicates treatment failure—the Aquablation literature shows that initial void trial failures do not predict long-term outcomes, with 98% ultimately voiding spontaneously. 5
- If a Foley catheter was placed and must remain temporarily, remove it within 48 hours to minimize infection risk, and use silver alloy-coated catheters if available. 1
Follow-Up Monitoring
- Repeat PVR measurement 4–6 weeks after initiating any intervention to assess response as post-operative inflammation resolves. 1, 2
- Maintain voiding diaries and symptom assessments to track improvement. 2, 6
- Monitor for recurrent UTIs, which may indicate persistent elevated PVR requiring continued intermittent catheterization. 2, 6
- No single PVR threshold alone mandates re-intervention—decisions must incorporate symptoms, quality of life impact, and complication risk, not just the PVR number. 1, 2, 6