Carlos Leon

Accuracy of Physical Examination in the Detection of Arteriovenous Fistula Stenosis

BACKGROUND AND OBJECTIVES Physical examination has been highlighted to detect vascular access stenosis; however, its accuracy in the identification of stenoses when compared with the gold standard (angiography) has not been validated in a systematic manner. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS A prospective study was conducted of 142 consecutive patients who were referred for an arteriovenous fistula dysfunction to examine the accuracy of physical examination in the detection of stenotic lesions when compared with angiography. The findings of a preprocedure physical examination and diagnosis were recorded and secured in a sealed envelope. Angiography from the feeding artery to the right atrium was then performed. The images were reviewed by an independent interventionalist who had expertise in endovascular dialysis access procedures and was blinded to the physical examination, and the diagnosis was rendered. Cohens kappa was used as a measurement of the level of agreement beyond chance between the diagnosis made by physical examination and angiography. RESULTS There was strong agreement between physical examination and angiography in the diagnosis of outflow (agreement 89.4%, kappa = 0.78) and inflow stenosis (agreement 79.6%, kappa = 0.55). The sensitivity and specificity for the outflow and inflow stenosis were 92 and 86% and 85 and 71%, respectively. There was strong agreement beyond chance regarding the diagnosis of coexisting inflow-outflow lesions between physical examination and angiography (agreement 79%, kappa = 0.54). CONCLUSIONS The findings of this study demonstrate that physical examination can accurately detect and localize stenoses in a great majority of arteriovenous fistulas.

Physical Examination of Arteriovenous Fistulae by a Renal Fellow: Does It Compare Favorably to an Experienced Interventionalist?

Physical examination (PE) has been highlighted to detect vascular access stenosis with high degree of accuracy when performed by an interventional nephrologist (IN) with expertise in physical examination. This study examines the accuracy of PE compared with angiography when performed by a nephrology fellow (NF). It also compares NF results to that of IN. Didactic and hands‐on PE training was provided to a renal fellow for 1 month during an interventional nephrology rotation. Forty‐five and 142 consecutive cases of arteriovenous fistula dysfunction were examined by the NF and IN, respectively. Preprocedure PE was performed by the NF and IN and the finding secured in a sealed envelope. Angiography from the feeding artery to the right atrium was then performed. The images were reviewed by an independent interventionalist with expertise in endovascular dialysis access procedures and the diagnosis was rendered. The reviewer was blinded to the physical examination. Cohen’s Kappa was used as a measurement of the level of agreement beyond chance between the diagnosis made by physical examination and angiography. Outflow stenosis: NF [strong agreement (81%), Kappa value = 0.63]; IN [strong agreement (89%), Kappa score = 0.78]. Inflow stenosis: NF [strong agreement (80%), Kappa value = 0.56]; IN [strong agreement (83%), Kappa score = 0.55]. These differences between NF and IN were not significant. NF performed significantly better than the IN regarding central vein stenosis. NF [strong agreement (79%), Kappa value = 0.44]; IN [weak agreement (11%), Kappa value = 0.17]. An NF can be trained in physical examination and accurately detect and localize stenoses in a great majority of arteriovenous fistulae when compared with an IN. We suggest that nephrology training programs should place more emphasis on this aspect of vascular access education.

Accuracy of physical examination in the detection of arteriovenous graft stenosis.

Physical examination has recently been demonstrated to detect vascular access stenosis in patients with arteriovenous fistulae. However, its accuracy in the identification of stenoses when compared with the gold standard (angiography) in patients with arteriovenous grafts has not been studied in a systematic fashion. We conducted a prospective study to examine the accuracy of physical examination in the detection of stenotic lesions when compared with angiography. Forty‐three consecutive cases referred for an arteriovenous graft dysfunction were included in this analysis. Preprocedure physical examination was performed. The findings of the examination and diagnosis were recorded and secured in a sealed envelope. Angiography from the feeding artery to the right atrium was performed. The images were reviewed by an independent interventionalist with expertise in endovascular dialysis access procedures and the diagnosis was rendered. The reviewer was blinded to the physical examination. Cohen’s Kappa was used as a measurement of the level of agreement beyond chance between the diagnosis made by physical examination and angiography. There was a strong agreement between the physical examination and the angiography in the diagnosis of vein‐graft anastomotic stenosis (kappa = 0.52). The sensitivity and specificity for this lesion was 57% and 89%, respectively. There was a moderate agreement beyond chance regarding the diagnosis of intragraft (kappa = 0.43) and inflow stenoses (kappa = 0.40). The sensitivity and specificity for the intragraft and inflow stenosis was 100%, 73% and 33%, 73%; respectively. The findings of this study demonstrate that physical examination can assist in the detection and localization of stenoses in arteriovenous grafts.

Strategies to Minimize Tunneled Hemodialysis Catheter Use

While the use of arteriovenous grafts has recently declined, there has been an astronomical increase in hemodialysis patients dialyzing with tunneled dialysis catheters (TDCs). Recent data have indicated that over 70% of the patients with end-stage renal disease initiate dialysis with a catheter. Additionally, up to 27% of the end-stage renal disease patients in the US are using TDCs as their permanent access, with placement rates having doubled since 1996. Although most modern catheters claim to provide adequate blood flow for dialysis, they are associated with the highest incidence of complications, morbidity and mortality when compared with other types of vascular access. It is for these reasons that the National Kidney Foundation Dialysis Outcomes Quality Initiative guideline 30 as well as the Fistula First Change Concept 7 emphasize limiting the use of catheters and fostering the creation of arteriovenous fistulae. Early referral has clearly been shown to minimize the use of TDCs and maximize fistulae. This report focuses on the role of additional measures that minimize TDC use, such as dialysis modality presentation and peritoneal dialysis, vascular access education, preoperative vascular mapping and salvage of early failure and thrombosed fistulae.

Salvage of Problematic Peritoneal Dialysis Catheters

Peritoneal dialysis (PD) is a markedly underutilized modality for permanent renal replacement therapy in the United States owing to a low rate of patient referral and high rate of patient dropout or transfer to hemodialysis. One cause for patient loss from PD is problematic PD catheters that often are removed rather than being subjected to simple surgical salvage procedures. We report three patients with problematic catheters and our approach to their management. The first patient developed erosion of the skin overlying the portion of the catheter between the deep and superficial cuffs after 6 months of PD. The second patient developed extrusion of the superficial cuff after 4 years of PD. The third patient demonstrated a localized abscess at the incision site for catheter insertion after 3 years of PD. Other than a mild superficial exit site infection and localized abscess in the second and third patient, respectively, there were no associated infections of the catheter tunnel and cuff or of the peritoneal cavity as determined by either clinical examination, ultrasound evidence of fluid collection, or cultures and white blood cell counts. All three cases were managed successfully by interventional nephrology on an outpatient basis and under local anesthesia without either catheter removal or placement of a new PD catheter. It was possible to continue uninterrupted PD in the first and third patients, while the second patient had temporary hemodialysis to allow for complete healing of the surgical wound. We conclude that in selected cases simple interventions can salvage problematic PD catheters and maintain patients on PD.

ASDIN Clinical Case Focus: Optimal Timing for Secondary Arteriovenous Fistula Creation: Devastating Effects of Delaying Conversion

A chronic hemodialysis patient was referred to interventional nephrology for evaluation of arteriovenous access dysfunction. The patient had been receiving hemodialysis using a left forearm brachiobasilic loop graft for the past 3 years. Physical examination revealed a hyperpulsatile graft. Angiography documented a critical stenosis at the vein–graft anastomosis and a well‐developed basilic vein from the elbow to the axillary region. Central veins were patent all the way to the right atrium. All attempts to navigate the wire across the stenosis failed. The patient was educated and counseled regarding the possibility of surgical creation of a secondary arteriovenous fistula (AVF). The images obtained were shared and discussed with the surgeon. A plan to create a secondary AVF using the basilic vein in the arm was made. A few months later the patient was referred to interventional nephrology, this time for thrombectomy of the same left arm loop graft. Thrombectomy could not be performed and a right internal jugular tunneled catheter was inserted. The patient again was referred to the surgeon for AVF creation. Six weeks later the patient was seen in the interventional laboratory for removal of the right internal jugular tunneled catheter. It was noted that instead of a fistula, the patient had received a right forearm brachiocephalic loop graft. Devastating consequences, such as the lost opportunity to create a fistula, insertion of a tunneled dialysis catheter, arteriovenous graft placement, exhaustion of available sites for fistula creation, and exposure to increased morbidity and mortality associated with grafts and catheters, can result if the opportunity to create a secondary AVF is not availed in a timely manner. This concept must be understood by every member of the vascular access team.

Optimal timing for secondary arteriovenous fistula creation: devastating effects of delaying conversion.

A chronic hemodialysis patient was referred to interventional nephrology for evaluation of arteriovenous access dysfunction. The patient had been receiving hemodialysis using a left forearm brachiobasilic loop graft for the past 3 years. Physical examination revealed a hyperpulsatile graft. Angiography documented a critical stenosis at the vein–graft anastomosis and a well‐developed basilic vein from the elbow to the axillary region. Central veins were patent all the way to the right atrium. All attempts to navigate the wire across the stenosis failed. The patient was educated and counseled regarding the possibility of surgical creation of a secondary arteriovenous fistula (AVF). The images obtained were shared and discussed with the surgeon. A plan to create a secondary AVF using the basilic vein in the arm was made. A few months later the patient was referred to interventional nephrology, this time for thrombectomy of the same left arm loop graft. Thrombectomy could not be performed and a right internal jugular tunneled catheter was inserted. The patient again was referred to the surgeon for AVF creation. Six weeks later the patient was seen in the interventional laboratory for removal of the right internal jugular tunneled catheter. It was noted that instead of a fistula, the patient had received a right forearm brachiocephalic loop graft. Devastating consequences, such as the lost opportunity to create a fistula, insertion of a tunneled dialysis catheter, arteriovenous graft placement, exhaustion of available sites for fistula creation, and exposure to increased morbidity and mortality associated with grafts and catheters, can result if the opportunity to create a secondary AVF is not availed in a timely manner. This concept must be understood by every member of the vascular access team.

ASDIN Clinical Case Focus: Optimal Timing for Secondary Arteriovenous Fistula Creation: Devastating Effects of Delaying Conversion: SECONDARY AVF CREATION

A chronic hemodialysis patient was referred to interventional nephrology for evaluation of arteriovenous access dysfunction. The patient had been receiving hemodialysis using a left forearm brachiobasilic loop graft for the past 3 years. Physical examination revealed a hyperpulsatile graft. Angiography documented a critical stenosis at the vein–graft anastomosis and a well‐developed basilic vein from the elbow to the axillary region. Central veins were patent all the way to the right atrium. All attempts to navigate the wire across the stenosis failed. The patient was educated and counseled regarding the possibility of surgical creation of a secondary arteriovenous fistula (AVF). The images obtained were shared and discussed with the surgeon. A plan to create a secondary AVF using the basilic vein in the arm was made. A few months later the patient was referred to interventional nephrology, this time for thrombectomy of the same left arm loop graft. Thrombectomy could not be performed and a right internal jugular tunneled catheter was inserted. The patient again was referred to the surgeon for AVF creation. Six weeks later the patient was seen in the interventional laboratory for removal of the right internal jugular tunneled catheter. It was noted that instead of a fistula, the patient had received a right forearm brachiocephalic loop graft. Devastating consequences, such as the lost opportunity to create a fistula, insertion of a tunneled dialysis catheter, arteriovenous graft placement, exhaustion of available sites for fistula creation, and exposure to increased morbidity and mortality associated with grafts and catheters, can result if the opportunity to create a secondary AVF is not availed in a timely manner. This concept must be understood by every member of the vascular access team.