Accuracy of Physical Examination and Intra‐Access Pressure in the Detection of Stenosis in Hemodialysis Arteriovenous Fistula

Abstract

Both physical examination (PE) and intra-access pressure (IAP) measurements have been used in the identification of stenosis in an arteriovenous access. The aim of this study was to evaluate the accuracy of PE and IAP in the diagnosis of arteriovenous fistula (AVF) stenosis. A total of 84 patients were enrolled in the study (54% men, mean age of 50.7 +/- 12.7 years and mean AVF patency of 24.9 +/- 7.8 months, 52% radiocephalic). Abnormalities of pulse and thrill were used as the diagnostic tools for the detection of stenosis using the physical examination. For IAP, stenosis was suspected when the ratio between IAP at the arterial puncture site and the mean blood pressure was <0.13 or >0.43. The diagnosis of stenosis was confirmed by Doppler ultrasound (DU). Sensitivity (S), specificity (SP), positive predictive value (PPV), negative predictive value (PNV), and accuracy were calculated for the two early detection tests. According to DU, 50 (59%) AVF were considered positive for the presence of stenosis. Fifty-six (66%) AVF were considered positive for the presence of stenosis by PE and 34 (40%) by IAP. S, SP, PPV, and NPV for PE and IAP were 96%, 76%, 86%, and 93% and 60%, 88%, 88%, and 60%, respectively. The accuracy for PE and IAP was 88% and 71%, respectively. PE proved to be an accurate method for the diagnosis of stenosis and should be part of all surveillance protocols of stenosis detection in AVF.

The Society for Vascular Surgery: Clinical practice guidelines for the surgical placement and maintenance of arteriovenous hemodialysis access

“…Clinical monitoring by skilled personnel was shown to have adequate diagnostic accuracy; clinical monitoring has been reported to have positive predictive value of 70% to 90% in prosthetic accesses and a specificity of 90% and a sensitivity of 38% 93% in autogenous accesses. [76][77][78][79] Therefore, in centers with skilled personnel, surveillance may not be as beneficial and produce marginal benefit vs clinical monitoring, as outlined above. However, this is not the practice in the real world, wherein physical examinations are seldom conducted and the first indication of an underlying stenosis is often access thrombosis.…”

Interventional Nephrology

“…This can be done with levels of accuracy that are quite acceptable (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15). In contrast to other approaches to AV access surveillance, it is simple to perform and does not require additional machines, regular calibrations, additional cost, or additional staff.…”

Surveillance and Monitoring of Dialysis Access

“…It also includes review of routine laboratory studies regularly obtained in the dialysis unit, dialysis adequacy (urea reduction ratio or Kt/V), and difficulties in cannulation or achieving hemostasis after needle withdrawal, documented recirculation, and other clinical clues. Physical examination of the access by an experienced individual has high sensitivity and specificity [8–10]. Measurement of dynamic venous pressure (DVP) during dialysis is currently considered as a monitoring strategy rather than a surveillance tool.…”