George X. Szymski

Significant on-call misses by radiology residents interpreting computed tomographic studies: Perception versus cognition

The purpose of this study was to evaluate the etiology of significant false-negative computed tomographic (CT) interpretations by radiology residents on-call. Over a 1-year period, significant on-call false-negative CT interpretations were analyzed to determine whether errors were perceptual (i.e., the resident did not see the finding or findings) or cognitive (i.e., the resident did not recognize the implications or misinterpreted a finding or findings). Significant “misses” were defined as errors that delayed surgical treatment or misdirected management in a potentially life-threatening manner.A total of 12 significant false-negative interpretations occurred over a 1-year period. All head CT misses (extraaxial hemorrhage, pneumocephalus, contusion, subarachnoid hemorrhage due to ruptured aneurysm) were perceptual errors. Misses on thoracic, abdominal, and pelvic CT scans (2 abscesses, abdominal aortic aneurysm rupture, superior vena cava perforation due to catheter placement, ischemic bowel, liver laceration, hypoperfusion syndrome, appendicitis) were mixed (4 cognitive and 4 perceptual errors).Since the diagnostic possibilities of emergency head CT scans are limited, residents missed only subtle, perceptual manifestations and had little difficulty interpreting findings when they were correctly recognized. The gamut of diagnostic possibilities in the thorax, abdomen, and pelvis was more challenging to residents on-call; errors in both perception and interpretation arose with equal frequency, and the significant error rate was higher than that for head CT interpretation. Junior residents, who make most of the significant on-call errors, commonly feel overwhelmed in attempting to assimilate the knowledge required to take call. Prepartion needs to be extensive, yet it should be focused on areas that will engender optimal impact on after-hours performance. When preparing residents to interpret on-call CT studies, perceptual manifestations of neuroradiology should be emphasized, whereas a more comprehensive approach to thoracic, abdominal, and pelvic disorders needs to be stressed.

Limitations of Percutaneous Treatment for Peripheral Arterial Vein Graft Stenoses

Peripheral arterial bypass vein graft stenosis is the leading cause of graft failure within the first 2 years following implantation. These lesions are generally secondary to myointimal hyperplasia and have historically been treated with graft revision or operative patch angioplasty. Unfortunately, graft revision or angioplasty requires reoperation through a scarred incision and usage of additional portions of autologous conduit. The purpose of this study is to assess the effectiveness of percutaneous transluminal angioplasty (PTA) in the treatment of vein graft stenosis. PTA was performed in 17 patent vein grafts in 16 patients for the treatment of perianastomotic and/or midvein graft stenoses occurring 7 ± 1 months (range 0.5-18 months) after graft implantation. Criteria for follow-up and patency adhered to the standards of the Ad Hoc Committee on Reporting Standards of the SVS/NAISCVS. After a mean follow-up of 17 ±3 months (range 2-44 months), the procedure-specific 18-month primary patency, primary-assisted patency, secondary patency, and limb salvage rates were 48 + 17%, 63 + 12%, 67 ± 12%, and 78 ± 15%, respectively. Subgroup analysis revealed favorable lesions (one or two focal lesions, < 1 cm length) in 11 grafts. Life-table analysis for this subgroup revealed primary patency, primary-assisted patency, secondary patency, and limb salvage rates of 68 ±20%, 90 ±9%, 90 ±9%, and 100%, respectively. The overall results of PTA for vein graft stenosis are poor and PTA should not be liberally applied to complex lesions. PTA may be a reasonable alternative to operative repair for focal vein graft stenoses in high-risk patients or in patients with limited remaining autologous conduit.

Cost-effectiveness of angiographic surveillance of dialysis access grafts after complete thrombosis

Cost-Effectiveness of Angiographic Surveil lance of Dialysis Access Grafts After Complete Thrombosis Navraj S. Grewal, MD, University of Chicago Hospitals, Chicago, IL, George X. Szymski, MD, Brian S. Funaki, MD Purpose: To determine the cost-effectiveness of routine angiographic surveillance of dialysis access grafts between episodes of thrombosis. Mater ia ls /Methods: Over a 1-year period, 50 patients presenting with thrombosis of dialysis access grafts were scheduled for routine angiographic surveillance at 1 month. At the time of surveillance, percutaneous angioplasty of venous and arterial stenoses was performed if necessary. The cost of maintaining graft patency in this group was compared to the cost of maintaining graft patency in patients who did not comply with the surveillance protocol. Most patients were included in both groups since compliance with follow-up visits between episodes of thrombosis was inconsistent. Results: In 50 patients, there were 92 cases of thrombosis after appropriate angiographic follow-up. The average cost of maintaining access of functioning grafts in this group was

Radiologic placement of subcutaneous infusion chest ports for long-term central venous access.

3821 per month. In 34 cases of thrombolysis without interval follow-up, the average cost of maintaining graft patency was

Portal vein stenosis in children with segmental liver transplants : treatment with percutaneous transhepatic venoplasty

5629 per month. The average patency of grafts with routine follow-up was 3.8 months; the average patency of grafts without angiographic follow-up was 2.1 months. Conclusion: Angiographic surveillance of dialysis access grafts after an event of thrombosis is cost effective and improves patency rates. Take H o m e Points: Surveillance via angiography is both cost effective and prolongs the patency of dialysis grafts after thrombolysis.