Prevalence of acute reactions to iopromide: postmarketing surveillance study of 74,717 patients.

BACKGROUND: Iodinated X-ray contrast media (CM) are recognized worldwide to be among the safest and most widely used injectable drugs. However, adverse drug reactions (ADRs) may still occur, ranging in severity from minor disturbances to severe and potentially fatal complications. PURPOSE: To prospectively determine the incidence and characteristics of acute ADRs during clinical utilization of a single nonionic monomeric contrast agent, iopromide, in routine radiological practice in a large number of nonselected patients. MATERIAL AND METHODS: 74,717 patients were enrolled in a prospective international postmarketing surveillance registry with iopromide (Ultravist; Bayer Schering Pharma AG, Berlin, Germany). A standardized questionnaire was used to collect the following patient information from 762 centers in 27 countries: baseline demographics, risk factors, premedication regimen, type of examination, route of injection, volume and selected concentration of iopromide, and overall tolerance to CM (utilizing specific criteria and descriptors). RESULTS: The overall rate of ADRs, including tolerance indicators (TI) (i.e., heat sensation and pain at the injection site), was 2%; when TIs were excluded, the rate was 1.5%. Fourteen serious adverse reactions were reported (rate 0.02%), of which none were fatal. There was a higher incidence of ADRs among women and for the age group ranging between 18 and 30 years. Patients with established risk factors, such as a history of previous CM reaction or allergic diathesis (7.4% and 4.1%, respectively), were at an increased risk for developing an ADR when compared to patients without risk factors (1.2%). The incidence of ADRs was not altered by the use of premedication. CONCLUSION: The safety of iopromide in routine clinical practice was shown to be comparable to the published safety profiles of other nonionic iodinated contrast agents. Adverse drug reaction rates were affected by age, gender, and risk factors (especially previous CM reactions or allergies), but not by premedication.

Selection of contrast media.

The pathophysiologic mechanisms of contrast-induced nephropathy (CIN) have been reviewed by Persson and Tepel. They focus on the renal response to contrast media (CM). In this section, we focus on the CM itself. Aspects of importance with regard to CIN include the route of administration, the volume of CM, the manner of X-ray attenuation, and the specific chemical structure of the CM.

Assessment of the vasodilator response in primary pulmonary hypertension. Comparing prostacyclin and iloprost administered by either infusion or inhalation.

AIMS: To directly compare the differential effects of oxygen, prostacyclin and iloprost (aerosolized and intravenous) in primary pulmonary hypertension. METHODS AND RESULTS: Twenty-one patients with severe primary pulmonary hypertension underwent right heart catheterization following oxygen inhalation, inhalation of aerosolized iloprost, intravenous prostacyclin or intravenous iloprost. The stability of the iloprost solution was tested for up to 4 weeks. Oxygen slightly decreased pulmonary vascular resistance. Intravenous prostacyclin (7.2+/-3.4 ng kg(-1) min(-1)) reduced pulmonary (1772+/-844 vs 1325+/-615 dyn s cm(-5), P<0.001) and systemic vascular resistance, and arterial and right atrial pressure, while cardiac output increased. Iloprost inhalation diminished pulmonary (1813+/-827 vs 1323+/-614 dyn s cm(-5), P<0.001) and systemic vascular resistance, and pulmonary artery (58+/-12 vs 50+/-12 mmHg,P<0.001) and right atrial pressure, while cardiac output increased. With intravenous iloprost (1.2+/-0.5 ng kg(-1) min(-1), n=8) a decrease in pulmonary (2202+/-529 vs 1515+/-356 dyn s cm(-5), P<0.05) and systemic vascular resistance and right a trial pressure occurred while cardiac output increased. Iloprost solution remained stable for 33 days while losing <10% (4 degrees C) of its active drug concentration.Conclusions Intravenous iloprost and prostacyclin have very similar haemodynamic profiles. In contrast, only inhaled iloprost exerted selective pulmonary vasodilation, reducing pulmonary vascular resistance and pulmonary artery pressure without systemic vasodilation. The longer half-life and extended stability despite lower costs render iloprost an attractive alternative to chronic prostacyclin treatment in primary pulmonary hypertension.

Transjugular intrahepatic portosystemic shunt with an autologous vein-covered stent: results in a swine model.

PURPOSE: To investigate the feasibility, safety, and efficacy of an autologous vein-covered stent (AVCS) to prevent shunt stenosis in a porcine transjugular intrahepatic portosystemic shunt (TIPS) model. MATERIALS AND METHODS: TIPS were created with an AVCS in 12 healthy domestic swine and with a bare stent in 10 additional swine. Tissue response was compared with use of venography, histology, and computerized morphometry analysis 2 weeks after implantation. Differences between AVCS and noncovered stents (established by a t-test), as well as regional differences within a single stent (established by an f test), were considered significant at P <.05. RESULTS: Twenty of 22 TIPS procedures were technically successful. Ten of 12 shunts with an AVCS (83%) and two of 10 with bare stents (20%) remained patent (<50% diameter narrowing) at euthanasia 2 weeks later (P <.01). Histologic evaluation of harvested bare stents showed marked intimal hyperplasia (IH), composed of smooth muscle cells, myofibroblasts, and fibroblasts. In contrast, the AVCS were remarkably free of IH and thromboses. In patent TIPS in both groups, endothelial coverage of the luminal surface was present histologically. IH accounted for 57% (26.27/45.79) of total stent cross-sectional lumen area in the control group and 21% (8.34/39.54) in the AVCS group (P <.01), with no intrashunt differences (P >.05). CONCLUSION: Based on short-term follow-up, AVCS significantly improved TIPS patency by prevention of both IH and in-stent thrombosis. TIPS created with an AVCS was feasible and safe in our porcine model.

Outcomes and performance of the Tesio twin catheter system placed for hemodialysis access.

PURPOSE: To assess the effectiveness of and outcomes with a twin catheter system. MATERIALS AND METHODS: The authors retrospectively reviewed the medical records, hemodialysis records, and clinical information system data from 132 consecutive patients who were referred for placement of a tunneled catheter for hemodialysis access. A commercially available twin catheter system was placed in all patients. Outcomes evaluated included infection rate, complication rate, and catheter malfunction and failure rates. Performance parameters evaluated included blood flow rates, urea reduction percentages, and recirculation percentages. RESULTS: One hundred eighty-four twin catheter systems were placed in 132 patients from January 11, 1996, to October 23, 1997. The initial technical success rate was 100%. There were four immediate procedural complications: Air emboli occurred in two patients, and prolonged bleeding necessitating intervention occurred in two. The total number of days a catheter was in place was 13,200 (mean, 74.6 days). Thirty-one infections occurred in 20 patients (total infection rate, 0.23 episodes per 100 catheter days). Sixty-five catheters malfunctioned during the study period, 19 of which necessitated removal, for a rate of 0.14 episodes per 100 catheter days. The average blood flow rate was 281.4 mL/min (range, 117.1-405.6 mL/min; median, 295.2 mL/min). Mean and median urea reductions were both 61%. Mean and median recirculation was 6.1% and 3.5%, respectively (range, 0%-31%). CONCLUSION: Percutaneous placement of the tunneled twin catheter system can be performed with excellent technical success and safety and acceptable catheter performance and outcomes for effective intermediate- to long-term hemodialysis.

Peripherally inserted central catheters: outcome as a function of the operator.

PURPOSE: To determine the natural history of and outcome involved with peripherally inserted central catheters (PICCs) placed at a single institution and examine potential differences in the natural history of PICCs placed by interventional radiologists (IRs) versus registered nurses (RNs). MATERIALS AND METHODS: A prospective analysis of all patients receiving PICCs at one academic medical center over a period of 6.5 months was conducted. At our institution, PICCs are placed primarily by RN members of the intravenous team. Placement procedures deemed unfeasible or problematic by RNs are referred to an IR for insertion under fluoroscopic guidance. A total of 322 PICCs (130 by IRs, 192 by RNs) were successfully placed in 256 patients. In three patients, placement was attempted but was a technical failure by both RNs and IRS: Seven patients in each group were lost to follow-up. PICCs were classified as successfully completed therapy or as having been prematurely removed, which was further stratified into suspected infection, occlusion, phlebitis, mechanical failure, inadvertent patient removal, and other. RESULTS: Overall rate of premature removal for PICCs placed by IRs versus RNs was not significantly different (30.8% vs 23.4%, respectively). PICCs placed by IRs had an increased rate of occlusion (IRs = 9.2%, RNs = 3.6%; P =.02). Other reasons for premature removal did not differ in incidence. Overall, PICCs were successfully placed in 99.1% of all patients and the course of therapy was completed in 69.3%. CONCLUSION: It is reasonable and cost-effective for trained RNs to place PICCs whenever feasible and refer complicated placements to IRS:

[Studies of cost-effectiveness and cost-usefulness in radiology]. / Etudes de coût-efficacité et coût-utilité en radiologie.

In the current context of significant increase of health care costs over the last decades, and in a system of global budget for health care, the concept of cost-effectiveness is one of the leading elements in the political decision making process for a given strategy. Therefore, it is important for the physician to be able to understand and critically interpret cost-effectiveness and cost-utility analyses. This article tries to illustrate comprehensively some of their key concepts. The perspective and the time horizon of the study should be clearly specified. The cost-effectiveness ratio is a synthetic summary based on a micro-costing approach in order to determine the true costs (numerator), and on an effectiveness (utility) assessment which should take into account the preferences of the community (denominator) in order to allow comparisons between interventions of different natures. Advances in the development of decision analysis softwares and in the standardization of the methodology of these studies have yielded considerable improvement in the reliability of their results. Several persisting methodological problems are the scope of current research, such as the discounting rate and the calculation of the minimal sample size required to reach a statistically significant threshold.

[Decision analysis in radiology]. / Analyse décisionnelle en radiologie.

Decision analysis is a technique which allows to clarify in an explicit, probabilistic and quantitative way the possible answers to a problem and to help the decision making process. The creation of algorithms, graphically displayed as decision trees in most cases, requires the introduction of quantitative information of two types: probabilities of the events that result from answering to the initial question, and utilities of the possible outcomes of these events. The choice of the optimal solution is based on the calculation of combinations of these data. Although the construction of models can be complex and time-consuming, their practical use has been simplified by the ease and user-friendliness of available softwares. To date, the applications of decision analysis in medicine have focused on cost-effectiveness studies and on the simulation of randomized trials. At the individual level, clinical applications of decision analysis could provide in a near future an interesting tool for the clinician involved in patient management. Even when doubts remain regarding the reliability of the data entered into the model, further sensitivity analysis provide a convenient way to test the validity of the drawn conclusions. This article hopefully offers a simplified and practical approach to basic decision analysis.

Comparison of a new stent and Wallstent for transjugular intrahepatic portosystemic shunt in a porcine model.

AIM: To evaluate a new balloon-expandable stainless steel stent (Cordis stent) in a transjugular intrahepatic portosystemic shunt (TIPS) porcine model and compared with Wallstent. METHODS: TIPS was performed in 26 normal domestic pigs weighing 20 kg-30 kg using a Cordis stent or Wallstent (13 pigs in each stent). All pigs were sacrificed at the 14th day after TIPS. The stent deployment delivery system, stent patency, and stent recoil after placement were evaluated. Proliferative response in representative histological sections from the center,hepatic and portal regions of the two stent designs were quantified. RESULTS: The shunt was widely patent in 4 pigs in the Cordis stent group (4/12, premature dead in 1 pig), and in 5 pigs in the Wallstent group (5/13). All remaining stents of both designs were occluded or stenotic. The mean quantified proliferation including thickness of the proliferation and the ratio of proliferation: total area in three assayed regions in Cordis stent and Wallstent was 2.18 mm:2.00 mm, and 59.18 mm2:51.66 mm2, respectively (P > 0.05). The delivery system and mechanical properties of the Cordis stent functioned well. CONCLUSION: The new Cordis stent is appropriate for TIPS procedure.