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Loss of Bruit Impending Fistula Thrombosis — ESENeph MCQ

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EasyHaemodialysisLoss of Bruit Impending Fistula ThrombosisESENeph

A 60-year-old man with CKD G5D on HD has a functioning AV fistula with a bruit and thrill. During clinical assessment, the bruit disappears and the thrill becomes weak. What does loss of bruit indicate?

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Correct answer: A — Loss of bruit with weakening thrill suggests impending fistula thrombosis from stenosis – urgent assessment (clinical and Doppler ultrasound) is needed; if thrombosis occurs, surgical thrombectomy or thrombolysis within 24-48 hours may salvage the access

A continuous bruit and palpable thrill are signs of a functioning AV fistula. Loss of bruit (particularly change from continuous to only systolic) and weakening thrill indicate reduced flow – most commonly from developing outflow stenosis leading to impending thrombosis. This is a vascular access emergency requiring urgent Doppler assessment. If stenosis is confirmed, pre-emptive angioplasty can prevent thrombosis. If thrombosis has occurred, surgical thrombectomy or pharmacomechanical thrombolysis within 24-48 hours may salvage the fistula. Beyond 48 hours, salvage rates drop significantly.

Reference: UKKA 2019 – VA; KDOQI 2019 – VA Update