Popliteal artery entrapment syndrome: ultrasound imaging, intraoperative findings, and clinical outcome.

OBJECTIVES: The purpose of this study was to report our experience with popliteal artery entrapment syndrome (PAES) with special emphasis on the applicability of duplex ultrasound scanning (DUS) when diagnosing PAES. In addition to examining the correlation between DUS and intraoperative findings in symptomatic limbs, the ultrasonic effect of plantar flexion in healthy volunteers were also evaluated. METHODS: During a 12-month period, 11 symptomatic limbs in 8 patients with a mean age of 29 years were referred with suspected PAES and enrolled consecutively. The popliteal artery was studied preoperatively with DUS in rest and during active plantar flexion. The popliteal artery was explored in all symptomatic limbs, and the intraoperative findings served as gold standard. Additionally, the popliteal arteries in 11 healthy volunteers (22 limbs) were evaluated with DUS during rest and plantar flexion. RESULTS: Intraoperative findings confirmed PAES in all 11 symptomatic limbs in accordance with the preoperative DUS examination. Surgical release of the popliteal artery was performed in 11 limbs. At a median follow-up of 15 months, all 11 limbs were free of ischemic symptoms and regained normalized popliteal flow on DUS. In the 22 symptom-free limbs, DUS showed normal popliteal flow during both rest and plantar flexion. CONCLUSIONS: In this series of patients with surgically confirmed PAES, we found preoperative DUS to have perfect agreement with the intraoperative findings in diagnosing PAES. The applicability of the method seems to be emphasized by the restoration of popliteal flow and relief of arterial insufficiency after surgical release in all patients, and by the fact, that none of the healthy volunteers were able to compress the popliteal artery during plantar flexion.

Balloon occlusion of the internal iliac arteries in the multidisciplinary management of placenta percreta.

OBJECTIVE: To evaluate our experience with prophylactic balloon occlusion of the internal iliac arteries as a part of a multidisciplinary algorithm for the management of placenta percreta. DESIGN: Consecutive case series. Setting. Rigshospitalet, Copenhagen University Hospital, Denmark. Sample. Seventeen women with placenta percreta. METHODS: Demographic characteristics, intraoperative data and outcomes are summarized and discussed. MAIN OUTCOME MEASURES: Feasibility of local resection, intraoperative blood loss and transfusion requirements. RESULTS: The multidisciplinary management allowed for local resections in nine of the 11 women who requested preservation of fertility. The mean intraoperative blood loss was 4050 mL (range 450-16 000 mL, median 2500 mL). Adhesions to the bladder or the parietal peritoneum were associated with an intraoperative blood loss >6000 mL. CONCLUSIONS: Prophylactic balloon occlusion of the internal iliac arteries as part of a multidisciplinary algorithm allowed for a safe management of all cases in our consecutive series of 17 women with placenta percreta. However, intraoperative blood loss and transfusion requirements were significant. We have therefore decided to modify our multidisciplinary algorithm to include balloon occlusion of the common iliac arteries rather than the internal iliac arteries.

Endovascular treatment of hemodialysis arteriovenous fistulas: is immediate post-interventional blood flow a predictor of patency.

PURPOSE: The purpose of this study was to investigate if the immediate hemodynamic outcome of an endovascular intervention on a dysfunctional hemodialysis arteriovenous fistula is a prognostic factor for primary patency. METHODS: This was a prospective observational study including 61 consecutive patients with dysfunctional arteriovenous fistulas referred to our endovascular unit. Patients were treated in accordance with institutional standard protocol including immediate pre- and post-interventional blood flow measurements using an intravascular catheter system. The primary endpoint was primary patency at 12 months in patients with an immediate post-interventional blood flow above or below 600 ml/min. Primary patency was estimated using the Kaplan-Meier method with the standard error of the estimate. Multivariate Cox regression analysis was used to study the effect of blood flow and other potential predictor variables. RESULTS: Post interventional flow did not significantly influence primary patency (p = 0.76). Primary patency was found to be affected by having a history of previous intervention(s) (p = 0.008, hazard ratio 2.9) or low fistula age (P=.038, hazard ratio 0.97 [one-month increase]). Primary patency in group 1 (previous intervention(s)) was 34% ± 13% at 12 months. In group 2 (no previous intervention), primary patency at 12 months was 62% ± 9%. CONCLUSIONS: The results of this study do not provide scientific support for using the immediate hemodynamic outcome of an intervention as a prognostic factor for primary patency. Low fistula age and a history of previous intervention in particular were found to reduce primary patency significantly.

Catheter-based flow measurements in hemodialysis fistulas - bench testing and clinical performance.

PURPOSE: The purpose of this study was to perform bench and clinical testing of a catheter-based intravascular system capable of measuring blood flow in hemodialysis vascular accesses during endovascular procedures. METHODS: We tested the Transonic ReoCath Flow Catheter System which uses the thermodilution method. A simulated vascular access model was constructed for the bench test. In total, 1960 measurements were conducted and the results were used to determine the accuracy and precision of the catheters, the effects of external factors (e.g., catheter placement, injection duration), and to test for systematic bias. In the clinical study, two interventional radiologists conducted a total of 250 measurements in 14 patients with arteriovenous fistulas to determine clinical precision and enable testing for bias between measurers. RESULTS: Accuracy was excellent for both catheters with a high level of agreement between results from the ReoCath Flow Catheter System and the reference flowmeter. Clinical precision, expressed as the mean coefficient of variation, was 5.9% and 4.7% for the antegrade and retrograde catheters, respectively. Flow measurements were significantly affected by the distance between a stenosis and the tip of a retrograde catheter with the effect being proportional to the degree of stenosis. There was no systematic bias between measurers. CONCLUSIONS: The Reocath Flow Catheter System was found to be accurate and precise. Reliable results require careful attention to catheter placement. Blood flow measurements provide unique information on the hemodynamic status of a vascular access and have the potential to optimize results of interventions.

Blood flow measurements during hemodialysis vascular access interventions--catheter-based thermodilution or Doppler ultrasound?

PURPOSE: To test the clinical performance of catheter-based thermodilution and Doppler ultrasound of the feeding brachial artery for blood flow measurements during hemodialysis vascular access interventions. METHODS: Thirty patients with arteriovenous fistulas who underwent 46 interventions had access blood flow measured before and after every procedure. Two methods, catheter-based thermodilution and Doppler ultrasound, were compared to the reference method of ultrasound dilution. Catheter-based thermodilution and Doppler ultrasound were performed during the endovascular procedures while flow by ultrasound dilution was determined within three days of the procedure. The methods were compared using regression analysis and tested for systematic bias. RESULTS: Failure to position the thermodilutional catheter correctly was observed in 8 out of 46 (17%) pre-intervention measurements. Post-intervention measurements and ultrasound measurements were feasible in all patients. The average level of agreement was good when comparing catheter-based thermodilution to ultrasound dilution. However, blood flow by ultrasound dilution may differ by ±130 mL/min (±22%) at a flow level of 600 mL/min by thermodilution. Results from Doppler ultrasound displayed a moderate level of agreement on average when compared to ultrasound dilution. Blood flow by ultrasound dilution may differ by ±160 mL/min (±27%) at a flow level of 600 mL/min by Doppler ultrasound. No systematic bias was detected by either method. CONCLUSIONS: On average, results from catheter-based thermodilution were more in agreement with results from the ultrasound dilution technique compared to Doppler ultrasound. However, considering the cost and the high technical failure rate of the thermodilutional system, we recommend the use of ultrasound.

Cephalic arch stenosis in autogenous brachiocephalic hemodialysis fistulas: results of cutting balloon angioplasty.

PURPOSE: Cephalic arch stenosis is a known cause of hemodialysis access failure in patients with brachiocephalic fistulas (BCFs). Outcomes of endovascular treatment are affected by resistance of the stenosis to balloon dilation, a high vein rupture rate and the development of early restenosis. The purpose of this retrospective study was to report outcomes after cutting balloon angioplasty (CBA) of cephalic arch stenosis. METHODS: In our vascular access database we identified 74 dysfunctional BCFs of which 30 (41%) were caused by cephalic arch stenosis. Seventeen fistulas in 17 patients (13 males and four females; median age 62 yrs; range 52-86) were treated with CBA (June 2005 to January 2008). Twenty-five procedures were performed. In 15 procedures, a cutting balloon was used alone and in 10 procedures CBA was followed by standard or high-pressure balloon angioplasty. Restenosis rates were calculated and patency rates were estimated with the Kaplan-Meier method. RESULTS: Primary patency rates (+/-SEE) at 3, 6, 12 and 15 months were 94% (+/-6%), 81% (+/-10%), 38% (+/-14%) and 22% (+/-15%), respectively. Assisted primary patency rates (+/-SEE) at the same intervals were 100% (+/-0%), 94% (+/-6%), 77% (+/-12%) and 63% (+/-13%), respectively. The mean interval between radiological interventions was 13 months (SD=8) and the mean number of interventions required per patient-year of dialysis was 0.9. CONCLUSION: Treatment of cephalic arch stenosis with CBA did not improve patency compared to published results of conventional PTA, but our results indicate that CBA may lower the frequency of required re-interventions.

Whole-body MR angiography with body coil acquisition at 3 T in patients with peripheral arterial disease using the contrast agent gadofosveset trisodium.

RATIONALE AND OBJECTIVES: Whole-body magnetic resonance angiography (WB-MRA) at 3 T with body coil acquisition has not previously been investigated. In this study, WB-MRA was performed in this manner using the blood pool contrast agent gadofosveset trisodium. MATERIALS AND METHODS: Eleven consecutive patients (five men, six women) with symptomatic peripheral arterial disease (two with critical limb ischemia, nine with claudication) were examined. Conventional digital subtraction angiography (DSA) of the aorta and the inflow and runoff arteries was used as the reference method. WB-MRA was performed using four slightly overlapping stations covering the arteries from the neck to the ankles. The arterial system was divided into 42 segments that were analyzed for the presence of significant arterial disease (> or =50% luminal narrowing or occlusion) by two blinded observers. RESULTS: Sensitivities for detecting a significant arterial lesion with WB-MRA using gadofosveset as the contrast agent were 0.66 (95% confidence interval [CI], 0.49-0.79) and 0.68 (95% CI, 0.52-0.81) for the two observers. Specificities were 0.82 (95% CI, 0.74-0.88) and 0.93 (95% CI, 0.87-0.96), respectively. Intermodality agreement between WB-MRA and DSA was moderate to good, with overall kappa values of 0.44 (95% CI, 0.29-0.59) and 0.63 (95% CI, 0.5-0.77) for the two observers. Interobserver agreement for WB-MRA was good, at kappa = 0.60 (95% CI, 0.50-0.71). CONCLUSION: WB-MRA at 3 T with body coil acquisition in patients with peripheral arterial disease showed good reproducibility but only moderate to good agreement with DSA. Further assessment of the method's clinical application is warranted.