Measurement of vessel diameter during angioplasty: are we accurately performing this task?

Vessel diameter is objectively measured by a lead ruler positioned in the fluoroscopic field and software calibration during angioplasty. We conducted a prospective study to evaluate the accuracy of lead ruler determination of vessel diameter. Chronic hemodialysis patients undergoing an angioplasty procedure were included in this study (n = 37). Vessel diameter was determined by calibrating the fluoroscopy machine to a ruler with lead markers placed in the fluoroscopic field. The same calibration was used to measure the fully effaced angioplasty balloon in its intravascular location. We compared the measured balloon diameter with the actual (manufacturer's) diameter. The approximate depth of the ruler from the measured vessel was also determined. Angioplasty balloons appeared 13.75-40.83% (mean 25.8% ± 7.015) smaller than the actual size of the balloon (p < 0.0001) when measured using a calibrated fluoroscopic machine. There was a tendency toward the fact that the bigger the distance between the ruler and the vessel (that contained the angioplasty balloon), the more likely the technique underestimated the size of the angioplasty balloon. Lead ruler method underestimates the diameter of the vessel. Recognizing such a discrepancy is important when determining the size of an angioplasty balloon or endovascular stent.

Balloon cinch deformity during angioplasty procedures: an indication for impending rupture.

Percutaneous transluminal balloon angioplasty (PTA) is a commonly performed procedure for hemodialysis vascular access dysfunction including thrombosis. While PTA is generally safe, balloon rupture during the procedure is a potential complication. Because such a rupture can cause damage to the blood vessel, indication of an imminent balloon rupture might help avoid such a complication. This analysis reports on six PTA procedures that were complicated by balloon rupture. All cases demonstrated terminal (caudal/cranial) cinch deformation. There was a loss of sharp terminal tapering and its replacement with banana silhouette before the balloon rupture. Importantly, the contour deformation and balloon rupture occurred at a pressure that was lower than the rated burst pressure. The cinch deformity can be used as an indication for impending balloon rupture. We suggest deflation of balloons that demonstrate shape deformations to avoid vascular injury.

Renal artery stenosis: to intervene, or not to intervene, "that is the question".

Renal artery stenosis (RAS) due to atherosclerosis continues to be a major cause of secondary hypertension. It can also lead to renal dysfunction due to ischemic nephropathy. While major clinical trials have emphasized that medical management should be preferred over angioplasty and stenting for the treatment of renal artery stenosis, clinical scenarios continue to raise doubts about the optimal management strategy. Herein, we present two cases that were admitted with hypertensive emergency and renal function deterioration. Medical therapy failed to control the blood pressure and in one patient, renal failure progressed to a point where renal replacement therapy was required. Both patients underwent angioplasty (for >90% stenosis) and stent insertion with successful resolution of stenosis by interventional radiology. Postoperatively, blood pressure gradually decreased with improvement in serum creatinine. Dialysis therapy was discontinued. At 4- and 8-month follow-up, both patients continue to do well with blood pressure readings in the 132-145/70-90 mmHg range. This article highlights the importance of percutaneous interventions in the management of atherosclerotic RAS and calls for heightened awareness and careful identification of candidates who would benefit from angioplasty and stent insertion.

Blood pressure recordings during hemodialysis access interventions: implications for acute management.

A retrospective study evaluating the pattern of blood pressure and its related complications before, during, and after percutaneous hemodialysis interventions was performed in patients presenting with asymptomatic hypertension. Hemodialysis patients undergoing percutaneous interventions including tunneled hemodialysis catheter insertion, percutaneous balloon angioplasty and thrombectomy procedure, and stage II hypertension (systolic blood pressure ≥160 mmHg) were included in this analysis. Blood pressure medications were not used while midazolam and fentanyl were routinely administered. Patients were followed for up to 4 weeks to monitor any complications. The mean blood pressure before, during, and after the procedures were 185 ± 18/96 ± 14, 172 ± 22/92 ± 15, and 153 ± 25/87 ± 14, respectively. There was a statistically significant difference between the blood pressure readings before and after the procedure (before = 185 ± 18/96 ± 14, after = 153 ± 25/87 ± 14; p = 0.001). None of the patients had a stroke, myocardial infarction, or acute pulmonary edema before, during, or after the procedure or during the 4-week follow-up period. A significant reduction in blood pressure was observed after the procedure without the administration of any antihypertensive medication. These results suggest that the reduction in blood pressure observed after percutaneous dialysis access interventions (particularly in the presence of midazolam and fentanyl) may make it unnecessary to treat asymptomatic hypertension prior to these procedures.

Radial artery harvest: a potential cause of arteriovenous access-associated hand ischemia.

Hand ischemia has multiple causes. In this article, we report an additional factor that can induce hand ischemia in hemodialysis patients. A 64-year-old white man with coronary artery disease underwent a coronary artery bypass graft procedure using the left radial artery as the bypass graft. Several months later, a left extremity Gracz fistula was created for arteriovenous access. Ever since dialysis was performed via the fistula the patient has experienced a cold hand and pain during dialysis that was somewhat relieved by wearing a woolen glove while on dialysis. Absence of the radial artery in the context of an ipsilateral arteriovenous access was highlighted as a possible etiology. A complete arteriography to determine the presence of stenoses, distal arteriopathy, and true steal was recommended, but the patient refused to undergo any investigation or procedure and instead decided to continue wearing the glove during the treatment. A plan for close follow-up and possible interventions in the event of worsening pain/ulceration was agreed upon. Radial artery harvest can result in hand ischemia if an ipsilateral arteriovenous access is created. We suggest that the contralateral extremity should be considered if an arteriovenous access is required to minimize this risk of this phenomenon.

Prevalence of chronic kidney disease in patients undergoing cardiac rhythm device removal.

Cardiac implantable electronic device (CIED) leads can cause central venous stenosis (CVS). In addition, these devices can get infected. Both are critically important considerations in patients with chronic kidney disease (CKD) for at least two reasons: (i) central veins serve as the final pathway should these patients need an arteriovenous access to provide dialysis therapy; and (ii) the presence of renal failure increases the risk of CIED infection. In this analysis, we investigated the prevalence as well as the degree of chronic kidney disease in patients harboring a CIED. Patients undergoing CIED removal were evaluated from 2001 to 2011. The patients were categorized into CKD stage I-V based on National Kidney Foundation-Dialysis Outcomes Quality Initiative guidelines. A total of 503 patients underwent CIED removal. Demographic characteristics revealed that 30% had hypertension, 44% were diabetics, 77% had coronary artery disease, and 84% suffered from congestive heart failure. Ninety percent (452/503) of the patients had CKD (stage I = I9 [4.2%], stage II = 189 [41.8%], stage III A = 96 [21.2%], stage III B = 59 [13.0%], stage IV = 45 [9.9%], and stage V = 44 [9.7%]). Overall, 148 (32.7%) patients (stage III B, stage IV, and stage V) of 452 had advanced renal failure. The results of this study reveal that one-third of CIED patients undergoing device removal have advanced chronic kidney disease.

High brachial artery bifurcation: clinical considerations and practical implications for an arteriovenous access.

High brachial artery bifurcation (HiBAB) is not a rare occurrence. Recent data have emphasized that HiBAB can have major clinical implications including high failure rate and decreased functional patency of an arteriovenous (AV) fistula. In this retrospective study, we investigated the incidence of HiBAB. Patients with advanced chronic kidney disease and end-stage renal disease on chronic hemodialysis undergoing preoperative vascular mapping for the creation of an AV access were included in this analysis. Ultrasound examination was used to map the arteries of the upper extremities. Four hundred and eighty-one arms in 340 patients were examined (right arm = 181, left arm = 300). Sixty-nine of the 481 (12.3%) demonstrated HiBAB. The internal diameter of the radial and ulnar arteries measured at the elbow region was found to be 2.9 ± 0.8 and 3.6 ± 1.0 mm, respectively (p = 0.0001). There were no statistically significant differences in terms of race, gender, and right versus left arms regarding the incidence of HiBAB. As HiBAB can be present in a significant number of patients and have an impact on the AV access, its presence should be evaluated during vascular mapping prior to an AV access creation.

Stent graft infection and protrusion through the skin: clinical considerations and potential medico-legal ramifications.

Stent grafts have been used for a variety of arteriovenous access associated issues. This article presents three cases of stent graft infection and a case of protruded metal piece of the stent graft through the skin. All four required surgical treatment and three cases required a tunneled dialysis catheter to provide long-term dialysis therapy. This report highlights that stent graft problems can occur that may result in loss of the access. Additionally, strut protrusion can pose a medical hazard to those performing preparation and cannulation of the arteriovenous access.

Contamination of transvenous pacemaker leads due to tunneled hemodialysis catheter infection: a report of 2 cases.

Catheter-related bacteremia is a frequent complication associated with the use of tunneled hemodialysis catheters. Catheter-related bacteremia can lead to metastasis of infection to other sites. This article presents 2 patients with transvenous pacemakers (placed >2 years ago) who were receiving long-term hemodialysis therapy using tunneled hemodialysis catheters. Both were admitted to the hospital with catheter-related bacteremia. Blood cultures showed methicillin-resistant Staphylococcus aureus (MRSA) in both cases. Transesophageal echocardiography was negative for the presence of valvular endocarditis, but showed lead-associated vegetation in both cases. Intravenous antibiotic therapy was initiated, and both the tunneled hemodialysis catheters and cardiac devices were removed by a cardiothoracic surgeon. The catheter tip and leads cultures showed MRSA in both cases. After resolution of bacteremia, both patients received an epicardial cardiac device. Antibiotic therapy was continued for 6 weeks. Renal physicians providing dialysis therapy should be aware that catheter-related bacteremia could cause contamination of transvenous pacemaker leads. Because catheter-related bacteremia is a frequent complication, epicardial leads might be considered as an alternative route to provide cardiac support to catheter-consigned patients. Epicardial leads do not navigate through the central veins, lie in the path of blood flow, or cause central venous stenosis.

Accuracy of ultrasound in the detection of inflow stenosis of arteriovenous fistulae: results of a prospective study.

While vascular ultrasound (US) has been highlighted to detect vascular access stenosis, its accuracy in the identification of inflow stenosis (IS) (anastomosis and/or juxta-anastomotic area) compared with the gold standard (angiography) has not been evaluated. One hundred three consecutive fistulae referred for interventions were included in this study. Preprocedure US of inflow segment was performed. Angiography from the feeding artery to the right atrium was then conducted. US comparison to angiography in the detection of IS (anastomosis and/or juxta-anastomotic area) was evaluated. Additionally, comparison of US to angiography in the assessment of juxta-anastomotic and anastomotic stenosis was reported separately. Data from 103 patients were available for analysis. Overall, US was negative for IS in 52 cases. Of these, 47 did not show a lesion on angiography. Only five cases demonstrated a stenosis on angiography. Fifty-one cases had IS by US, 50 were confirmed by angiography while one case did not show a lesion on angiography. Consequently, US had a sensitivity of 91%, specificity of 98%, and positive and negative predictive values were 98% and 90%, respectively. The sensitivity, specificity, negative, and positive predictive values for juxta-anastomotic and anastomotic lesions evaluated separately were 92%, 98%, 92%, 98% and 79%, 100%, 95%, 100%, respectively. Linear regression analysis showed a significant positive correlation between US and angiography for anastomotic (r2=0.71, p<0.0001; slope=0.63+/-0.098 and intercept=24+/-6) and juxta-anastomotic stenosis (r2=0.71, p<0.0001; slope=0.68+/-0.060 and intercept=23+/-4). These results reveal that US has a high degree of accuracy in the detection of IS.

A novel technique for tethered dialysis catheter removal using the laser sheath.

Traction and cutdown techniques can successfully remove a tunneled dialysis catheter (TDC) in a great majority of patients. However, these methods may not be successful in patients with catheters that are tethered or attached to the central veins or the atrium. A forceful application of traction can lead to catheter breakage with subsequent retention of the broken piece and carries a potential risk of vascular and atrial wall avulsion. Open thoracotomy has been employed to remove an attached TDC. However, this procedure is invasive and bears a significant morbidity. This report presents three cases of tethered TDCs that underwent laser sheath extraction. The TDCs had been in place for an average of 26 months. The patients underwent initial unsuccessful removal attempt using the traction method with surgical exploration all the way to the venotomy site. The laser technique that is used to remove pacemaker/implantable cardioverter defibrillator leads was then applied to these stuck catheters. All three catheters were successfully removed without any damage to the catheter, central veins, or the right atrium. There were no retained catheter fragments left in the central veins or the atrium. One patient demonstrated a significant thrombus that extended from the tip of the catheter all the way to the right ventricle. The external sheath of the laser device successfully aspirated the thrombus. There were no procedure-related complications. In this small series, a laser sheath successfully extracted tethered dialysis catheters. The study found the procedure to be effective, easy to perform, and minimally invasive. We suggest that this approach be considered for the removal of tethered catheters that cannot be removed using traditional approaches.

Impact of surgeon selection on access placement and survival following preoperative mapping in the "Fistula First" era.

According to the "Fistula First Initiative" surgeon selection should be based on best outcomes, willingness, and ability to provide access services. This analysis presents arteriovenous access placement and outcomes in 75 patients when surgery was performed by one of two dedicated high-volume vascular access surgeons (community [surgeon I] and academic medical center [surgeon II]). Preoperative vascular mapping was performed in all the patients. Demographic characteristics were similar except that patients referred to surgeon I (n = 40) were older (52.7 +/- 16.2 years vs. 45.4 +/- 13.7 years; p = 0.04) and tended to have more previously failed accesses (50% vs. 29%; p = 0.06) and black race (65% vs. 43%; p = 0.055) including a history of previously failed accesses (50% for surgeon I and 29% for surgeon II; p = 0.06). Similarly, there was no significant difference in the size of forearm ([surgeon I: 2.0 +/- 1.0 mm], [surgeon II: 1.9 +/- 0.8 mm]; p = 0.45) or upper arm veins (cephalic vein: surgeon I = 3.2 +/- 1.4 mm, surgeon II = 2.9 +/- 1.2 mm, p = 0.34; basilic vein: surgeon I = 5.0 +/- 1.2 mm, surgeon II = 4.7 +/- 1.3 mm, p = 0.25). Fistulae placement occurred in 98% vs. 71% (p = 0.001) for surgeon I and II, respectively. Characteristics predictive of fistula placement over an arteriovenous graft were surgeon selection (odds ratio [OR] = 19.52; p = 0.01) and no history of diabetes (OR = 7.61; p = 0.016). Kaplan-Meier analysis revealed 6 and 12 months overall access survival rates of 82%, 58% and 82% and 47% for surgeon I and II, respectively (p = 0.007). This analysis demonstrates that surgeon selection can have a significant impact on the rate of fistula placement and its overall survival despite similar findings on preoperative vascular mapping.

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.

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. Cohen's 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.

Utility of static pressure ratio recording during angioplasty of arteriovenous graft stenosis.

Intra-access static pressure ratio (SPR) (intra-access pressure/mean arterial pressure) can be measured during angioplasty (PTA) to assess the functional importance of an arteriovenous graft (AVG) stenosis. We used SPR in 70 patients with AVGs who underwent 98 angioplasty procedures. SPR was measured during angioplasty by placing a catheter tip at mid-access. Inflow stenosis (IF) = stenosis proximal to the tip of the catheter. Outflow stenosis (OF) = stenosis distal to the tip of the catheter up to the superior vena cava-atrial junction. Post PTA, access flow (Qa) was assessed within 2 weeks. Complete data sets for both SPR and Qa were available in 83 procedures. Using a normal SPR ratio of 0.3-0.4 at mid-graft, three patterns of SPR were noted. In 63 of 83 (76%) cases SPR was elevated prior to PTA (0.71 +/- 0.13 SD). PTA reduced SPR toward normal range (0.44 +/- 0.12) in 53 cases (84%). In the remaining 10 (16%), SPR decreased to a low value (0.22 +/- 0.03) and normalized (0.40 +/- .0.11) only after PTA of a coexisting inflow stenosis. In 12 of 83 (14%) procedures, the initial SPR was low (0.18 +/- 0.04) and increased toward normal (0.3 +/- 0.08) following IF stenosis PTA in seven (58%) cases. For the remaining five (42%) cases SPR increased to a high value (0.70 +/- 0.21) and decreased toward normal range (0.33 +/- 0.07) only after OF stenosis angioplasty. In 8 of 83 (10%) procedures, initial SPR was normal (0.33 +/- 0.02). Angiography revealed coexisting IF and OF stenoses. SPR remained within the normal range after PTA of these lesions (0.33 +/- 0.02). Qa increased significantly in 74 of 83 (89%) procedures (before = 572 +/- 201, after = 1109 +/- 368 ml/min; p < 0.001). SPR measurements can assist in hemodynamic assessment of an AVG during angioplasty procedure.

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.

Arterial steal syndrome: a modest proposal for an old paradigm.

BACKGROUND: Access ligation has been considered to be the treatment for patients presenting with arterial steal syndrome by many nephrologists. We report results of a prospective study using comprehensive arteriography coupled with percutaneous transluminal balloon angioplasty (PTA) or surgical intervention to evaluate and manage steal syndrome. METHODS: Twelve consecutive patients referred for symptoms of steal syndrome were examined. Comprehensive arteriography of the extremity to diagnose arterial stenoses and delineate anatomy was performed by advancing a diagnostic catheter into the subclavian artery. Findings of arteriography and degrees of stenosis before and after PTA also were documented. Resolution of symptoms after PTA and surgical interventions, as well as complications, were recorded. RESULTS: Angiography showed arterial stenotic lesions in 10 of 12 patients (83%). The degree of stenosis was 66% +/- 14% (SD). Eight patients (80%) with stenotic lesions underwent PTA successfully. The degree of stenosis after PTA was 13% +/- 10%. The remaining 2 patients were not considered candidates for PTA and were referred to surgery with arteriography images. One patient underwent ligation and the other patient required an axillary loop fistula using the same outflow vein. The 2 patients without stenoses showed excessive steal through the anastomosis and underwent lengthening procedures by insertion of a vein segment. All 12 patients are symptom free with a mean follow-up of 8.3 +/- 4 months, and 11 of 12 patients (92%) are dialyzing using the same access. There were no procedure-related complications. CONCLUSION: We suggest that complete imaging of the arterial circulation of the extremity be considered in patients presenting with symptoms of steal syndrome to properly assess the arterial anatomy and develop a treatment strategy.

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.