Assessment of occlusion of the vascular access in patients on chronic hemodialysis: Comparison of physical examination with continuous-wave Doppler ultrasound

Background: Dialysis access occlusion is the most common cause of hospitali zation and a frequent indirect cause of mortality in patients on chronic he modialysis. The clinical assessment of an arteriovenous shunt is presently the most widely adopted method for the diagnosis of vascular access occlusi on in hemodialysis patients, but no studies have yet investigated objective ly its sensitivity and positive predictive value (PPV). Continuous-wave (CW ) Doppler ultrasound is a simple, inexpensive, and noninvasive technique fo r the assessment of arterial blood flow. We have carried out a prospective evaluation of the PPV of CW Doppler for the diagnosis of vascular access oc clusion in hemodialysis patients and compared it with clinical investigatio n. Methods: Fourty-one hemodialysis patients with clinical diagnosis of occ lusion of their fistula were studied, and in 23 of them the diagnosis of oc clusion was objectively validated. Results: CW Doppler in the patients in w hom occlusion was objectively validated showed PPV of 86 and 83% under basa l conditions and after fistula compression, respectively, with sensitivitie s of 95 and 100%, respectively. Clinical diagnosis, under the same conditio ns, showed a PPV of 83% and a sensitivity of 100%. Conclusions: CW Doppler and clinical examination have a similar high sensitivity for the diagnosis of occlusion of the dialysis access; thus, there is no need to use routinel y Doppler CW examination, unless objective documentation is required.