Peter N. Waybill

Venous thrombosis associated with the placement of peripherally inserted central catheters.

PURPOSE Peripherally inserted central catheters (PICCs) have become an essential component of the management of an increasing number of patients, including patients who may require hemodialysis. Reported symptomatic venous thrombosis rates associated with PICC lines are based on clinical signs and symptoms and range from 1% to 4%. The purpose of this study is to evaluate the true rate of thrombosis of upper extremity veins after the placement of PICCs and the potential impact on future access in hemodialysis patients. MATERIALS AND METHODS A retrospective analysis was performed. Patients who had (i) normal findings during initial venography, (ii) PICC placement, and (iii) who underwent subsequent repeated venography were included. Age, sex, vein cannulated, catheter size, location, and incidence of thrombosis were analyzed. RESULTS Three hundred fifty-four PICCs were placed in 119 patients. Of the 144 extremities, 137 had normal findings during initial venography. Of the 137 extremities, 32 developed thrombosis of the cannulated vein (or central veins) after initial PICC placement (23.3%). When all extremities with multiple PICC lines placed were considered, 52 developed thrombosis, for an overall thrombosis rate of 38%. The incidence of thrombosis by site was cephalic 57%, basilic 14%, and brachial 10%. No significant differences were noted in the rates of thrombosis by age, sex, or catheter size. CONCLUSIONS There is a relatively high rate of venous thrombosis associated with PICCs, particularly cephalic thrombus. Because of the high rate of thrombosis associated with these catheters, an alternative mode of access should be considered in current or potential hemodialysis patients. All patients with a history of PICC line placement requiring dialysis access should undergo upper extremity venography prior to the placement of permanent access.

Contrast media-induced nephrotoxicity: identification of patients at risk and algorithms for prevention.

NEARLY 70 years ago, Osborne et al (1) first reported the imaging of the urinary tract using iodinated contrast material. In the last 30 years, there has been a marked increase in diagnostic and interventional procedures in which iodinated contrast is used. The structure of radiocontrast agents has been modified over the last several decades, yielding compounds with significantly less chemotoxicity. Unfortunately, the administration of even the newest radiocontrast agents may cause nephrotoxicity. Contrast media-induced nephropathy (contrast nephropathy; CN) has been reported to be the third-leading cause of acute renal failure in hospitalized patients (2–5), occurring at a rate of 1%–6% in unselected patient populations (4,5), and up to 40%–50% in high-risk patient populations (6–8). Unfortunately, it is frequently this higher-risk group, particularly those with preexisting renal insufficiency and diabetes mellitus, which is encountered by the cardiovascular and interventional radiologist. Based on multiple laboratory and clinical investigations performed over the last decade, the current discussion will focus on the pathogenesis and clinical presentation of CN, identification of patients at higher risk of developing CN, and interventions that may diminish the risk of CN.

Complications of percutaneous transhepatic biliary interventions

Complications of percutaneous transhepatic biliary drainage procedures range from skin discomfort to life-threatening arterial hemobilia. A thorough understanding of biliary anatomy and postprocedure care is essential if such procedures are to be performed. This article summarizes the anatomic, technical, and clinical issues related to biliary interventions and assists the interventional radiologist in the management of complications encountered in patients undergoing biliary interventions.

Deep venous thrombosis after percutaneous insertion of vena caval filters

PURPOSE A large multicenter study has recently questioned the overall clinical efficacy of vena caval filters, especially when inserted prophylactically, because of the subsequent development of deep venous thrombosis (DVT) at the insertion site. We examined the incidence of this complication with newer, smaller diameter percutaneous devices. METHODS We reviewed our vascular surgery and interventional radiology clinical registries to identify patients in whom a femoral percutaneous vena caval filter had been placed from 1993 to 1998. This list was cross referenced with patients who had undergone lower extremity venous ultrasound scan examinations for the diagnosis of DVT in the vascular laboratory within a 60-day period before and after the insertion of the filter device. RESULTS A total of 35 patients during this 5-year period had timely follow-up venous duplex scan studies performed. The indications for filter placement were DVT in 16 patients (46%), pulmonary embolus in 13 patients (37%), DVT and pulmonary embolus in three patients (9%), and prophylactically in three patients (9%) at high risk for thromboembolization. Of the patients with documented thromboembolic events, 91% (29 of 32) had contraindications to anticoagulation therapy, and the remaining 9% (3 of 32) represented failure of anticoagulation therapy. A Greenfield filter was used in 13 patients (37%), a Simon Nitinol filter was used in 11 patients (31%), and a VenaTech filter was used in nine patients (26%). The other two patients (6%) had a Birds Nest filter inserted. At a mean follow-up period of 12 +/- 2 days (median, 6 days), there was a 40% (14 of 35) incidence of proximal DVT in venous segments without evidence of thrombus before filter insertion. The majority (71%; 10 of 14) occurred in the common femoral vein, with three located in the superficial femoral vein and one in the external iliac vein. The lowest incidence of DVT was seen with the Greenfield and Birds Nest filters as compared with the smaller Simon Nitinol and VenaTech filters (20% vs 55%; P < .05). The highest incidence of thrombosis occurred in patients with pre-insertion pulmonary emboli (50%; 8 of 16) as compared with those patients with DVT (38%; 6 of 16) and prophylactic insertion (0%; 0 of 3). However, the subgroups were too small to attain statistical significance. CONCLUSION There is a continuing and significant incidence of new DVT development ipsilateral to the percutaneous femoral insertion site of vena caval filters. The smaller diameter filters are not associated with a lower incidence of femoral thrombosis.

Fractured Bard Recovery, G2, and G2 Express Inferior Vena Cava Filters: Incidence, Clinical Consequences, and Outcomes of Removal Attempts

PURPOSE To increase the understanding of risks of inferior vena cava (IVC) filter fracture and embolization and the safety of removing fractured filters via retrospective review of a prospectively collected database of fractured IVC filters. MATERIALS AND METHODS A total of 63 fractured IVC filters were discovered among 548 patients presenting for retrievable filter removal between April 2004 and November 2010 at a single institution. Device type, duration of implantation, component fracture, and embolization events were recorded. Success rates and techniques for removal of components were recorded. RESULTS A total of 63 fractured Recovery, G2, and G2 Express IVC filters were identified, for an overall fracture rate of 12%. Excluding foot process fractures, the fracture rate for only filter arms and/or legs was 6%. The incidence of fracture increased with longer filter dwell times. Success rates for removal of the nonfractured component (ie, main body) and fractured components (ie, arm or leg) were 98.4% and 53.4%, respectively. The distal embolization rate of fractured filter components was 13%. There were no immediate clinically significant complications associated with fracture component embolization or filter removal. A single patient was encountered with symptoms related to their fractured filter. CONCLUSIONS IVC filter fracture rates increase with longer dwell times; however, removal of fractured filters and fractured components (ie, arms and legs) can be achieved safely and effectively. Clinically significant complications of IVC filter fracture are rare, and there were no immediate clinical sequelae related to embolization of fracture components.

Comparison of the recovery and G2 filter as retrievable inferior vena cava filters.

PURPOSE To compare the technical success of the Recovery and G2 filters as retrievable inferior vena cava (IVC) filters. MATERIALS AND METHODS Recovery (n = 128) and G2 (n = 113) filters were placed in the IVCs of 241 patients with the intent of retrieval. The referring physician and/or patient were contacted at 6-month intervals to ensure filter retrieval when indicated. The Recovery and G2 filter groups were compared regarding technical success of filter placement, technical success of attempted retrieval, filter tilt, filter migration, filter fracture, and filter efficacy. RESULTS Filter placement was technically successful in 95% of Recovery filters (n = 122) and 100% of G2 filters (n = 113). Recovery filter retrieval was attempted in 55% of patients (n = 71) at a mean of 228 days (range, 0-838 d) after filter placement. G2 filter retrieval was attempted in 55% of patients (n = 62) at a mean of 230 days (range, 7-617 d) after filter placement. Technical success rates of filter retrieval were 94% (n = 67) and 97% (n = 60) in the Recovery and G2 filter groups, respectively. The G2 filter group had significantly fewer cases of (i) filter tilt at placement, (ii) filter tilt at attempted retrieval, and (iii) filter fracture than the Recovery filter group. In the G2 filter group, there was a significantly higher technical success rate of filter placement and there were more cases of caudal filter migration than in the Recovery filter group. CONCLUSIONS Compared with the Recovery filter, the G2 filter is associated with significantly less filter fracture and tilt, greater technical success of filter placement, and more caudal filter migration.

Complications and controversies associated with peripherally inserted central catheters.

The placement of peripherally inserted central catheters has grown into one of the most common forms of intravenous access. Although complications associated with peripherally inserted central catheters are low, most healthcare providers will encounter them on a frequent basis. Awareness of these complications will help the clinician manage these issues appropriately.

Arterial and Venous Smooth Muscle Cell Proliferation in Response to Co-culture with Arterial and Venous Endothelial Cells☆

PURPOSE To determine whether definable differences exist between arterial and venous smooth muscle cells (SMCs), as measured by proliferative response to co-culture with arterial or venous endothelial cells (ECs). MATERIALS AND METHODS Human aortic ECs (A-ECs) and saphenous vein ECs (V-ECs) were cultured opposite either aortic SMCs (A-SMCs) or saphenous vein SMCs (V-SMCs). At selected time intervals, SMCs were counted by fluorescence microscopy. RESULTS In the presence of an intact EC monolayer, A-ECs induced a 9%-31% increase in A-SMC (P < or = .001) and a 15%-37% increase in V-SMC (P < or = .001) proliferation. Saphenous vein ECs induced a 50%-71% increase in A-SMC (P < or = .001) and a 40%-62% increase in V-SMC (P < or = .001) proliferation. The small proliferative difference between A-SMCs and V-SMCs was significant for co-culture with A-ECs (P < or = .001) and V-ECs (P < or = .001). Of note, compared to A-ECs, V-ECs induced a significantly greater A-SMC (P < or = .001) and V-SMC (P < or = .001) proliferative response. CONCLUSION A small, but definable, difference exists between A-SMCs and V-SMCs, as measured by proliferative response in co-culture with A-ECs and V-ECs.

Smooth muscle cell proliferation in response to co-culture with venous and arterial endothelial cells.

PURPOSE The critical role of endothelial cells (ECs) in arterial disease is well established, but little is known of their role in venous disease. Previous studies suggest inherent differences between arteries and veins: arterial stenoses demonstrate a large lipid component, whereas hemodialysis-related venous stenoses are characterized by marked smooth muscle cell (SMC) proliferation. This study compares effects of venous versus arterial ECs on SMC proliferation in co-culture. MATERIALS AND METHODS Human saphenous vein ECs (HSV-ECs) or human aortic ECs (HA-ECs) were cultured on the underside of 10-micron, porous polycarbonate membranes and allowed to grow to confluence for 48 hours. After EC confluence, human aortic SMCs (HA-SMCs) were cultured on the membranes opposite the EC (day 0). On days 0, 1, 2, 4, 6, and 8, membranes were harvested (n = 3 per day), stained with Hoechst dye, and HA-SMCs were counted by fluorescence microscopy. Controls were HA-SMCs cultured alone. Comparisons were made by two-way multivariate analysis of variance. RESULTS During the entire 8-day period, there was significant induction of HA-SMC proliferation by both HSV-ECs (P = .0003) and HA-ECs (P = .0012). Maximal inductions were 88% +/- 11% for HSV-ECs (P = .0015) and 24% +/- 6% for HA-ECs (P = .0015). HSV-ECs exhibited a three- to ninefold greater induction than HA-ECs (P = .0003). CONCLUSION HSV-ECs induce adjacent HA-SMC proliferation, possibly in a paracrine manner to a significantly greater extent than HA-ECs.

Determination of inferior vena cava diameter in the angiography suite: Comparison of three common methods

PURPOSE Significant inferior vena cava (IVC) filter migration has been associated with deployment of some filter types in IVCs measuring more than 28 mm in diameter at inferior vena cavography. The purposes of this study were to (a) determine if significant differences exist between IVC measurements obtained using a gold standard technique and two other widely accepted methods, and (b) if differences exist, how often do these differences cause incorrect IVC sizing around a diameter of 28 mm, with its associated filter migration issues. MATERIALS AND METHODS One hundred thirteen consecutive inferior vena cavograms were retrospectively reviewed. The transverse diameter of the infrarenal IVC was determined by using a calibrated intravascular catheter (the gold standard), subtraction of 20% from the measured transverse IVC diameter on a cut-film radiograph, and a radiopaque ruler placed immediately posterior to the patient. RESULTS The concordance correlation of the 20% magnification method versus internal calibration was 0.94. Kappa analysis to determine agreement at a diameter of 28 mm yielded a Kappa coefficient of 0.490. The concordance correlation of an external ruler versus internal calibration was 0.43, with a Kappa coefficient of 0. CONCLUSION The poor Kappa correlations for both methods demonstrate that they are unreliable in identifying megacava. Inferior vena cavography prior to IVC filter placement should be performed with a calibrated intravascular catheter.