Clinical endpoints in peripheral endovascular revascularization trials: a case for standardized definitions.

BACKGROUND: Endovascular therapy is a rapidly expanding option for the treatment of patients with peripheral arterial disease (PAD), leading to a myriad of published studies reporting on various revascularization strategies. However, these reports are often difficult to interpret and compare because they do not utilize uniform clinical endpoint definitions. Moreover, few of these studies describe clinical outcomes from a patients' perspective. METHODS AND RESULTS: The DEFINE Group is a collaborative effort of an ad-hoc multidisciplinary team from various specialties involved in peripheral arterial disease therapy in Europe and the United States. DEFINE's goal was to arrive at a broad based consensus for baseline and endpoint definitions in peripheral endovascular revascularization trials for chronic lower limb ischemia. In this project, which started in 2006, the individual team members reviewed the existing pertinent literature. Following this, a series of telephone conferences and face-to-face meetings were held to agree upon definitions. Input was also obtained from regulatory (United States Food and Drug Administration) and industry (device manufacturers with an interest in peripheral endovascular revascularization) stakeholders, respectively. The efforts resulted in the current document containing proposed baseline and endpoint definitions in chronic lower limb PAD. Although the consensus has inevitably included certain arbitrary choices and compromises, adherence to these proposed standard definitions would provide consistency across future trials, thereby facilitating evaluation of clinical effectiveness and safety of various endovascular revascularization techniques. CONCLUSION: This current document is based on a broad based consensus involving relevant stakeholders from the medical community, industry and regulatory bodies. It is proposed that the consensus document may have value for study design of future clinical trials in chronic lower limb ischemia as well as for regulatory purposes.

Evaluation of a modified arrow-trerotola percutaneous thrombolytic device for treatment of acute pulmonary embolus in a canine model.

PURPOSE: Massive pulmonary embolus (PE) is often rapidly fatal. Surgical thrombectomy has a mortality rate as high as 74%. Multiple percutaneous methods have been tested with limited success. The purpose of this study was to evaluate the Arrow-Trerotola percutaneous thrombolytic device (PTD) for (i) the ability to clear pulmonary embolus and (ii) the effect on normal pulmonary vasculature. These were tested in a canine model. MATERIALS AND METHODS: Iatrogenic unilateral massive PEs were created in nine canines. These PEs were then treated with the PTD. The device was also activated in the normal pulmonary artery. Immediately after treatment, six animals were killed. Three animals were allowed to recover and underwent pulmonary arteriography 1 month later to evaluate pulmonary hypertension, stenosis, or occlusion; they were then killed. Autopsy specimens were evaluated for histologic evidence of acute or chronic vascular injury. RESULTS: Acutely, the PTD effectively thrombolysed the PE in all animals. Histologically, there was moderate intimal injury, but no evidence of pulmonary artery disruption. There was one device failure. One month after treatment, there was no radiographic evidence of pulmonary stenosis at device activation sites, no pulmonary hypertension, and only mild histologic evidence of scar formation. CONCLUSION: In preliminary animal testing, the PTD is safe and effective for treating large central pulmonary emboli. Human clinical trials are warranted.

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.

Treatment of thrombosed hemodialysis access grafts: Arrow-Trerotola percutaneous thrombolytic device versus pulse-spray thrombolysis. Arrow-Trerotola Percutaneous Thrombolytic Device Clinical Trial.

PURPOSE: To evaluate a percutaneous thrombolytic device (PTD) designed for treating thrombosed hemodialysis access grafts. MATERIALS AND METHODS: To compare the PTD with pulse-spray pharmacomechanical thrombolysis (PSPMT) by using urokinase, 122 randomly chosen patients with synthetic, thrombosed hemodialysis access grafts from multiple centers prospectively underwent thrombolysis with the PTD (5-F, low-speed rotational mechanical device) or PSPMT. Major outcome variables included the procedure time, the immediate technical patency rate, the complication rate, and the 3-month patency rate. RESULTS: Sixty-four PTD and 58 PSPMT procedures were performed with intent to treat. The immediate technical patency rate was 95% (61 of 64 [PTD] and 55 of 58 [PSPMT]) in both procedures. Median procedure times were 75 minutes in the PTD group (range, 25-209 minutes) and 85 minutes in the PSPMT group (range, 50-273 minutes; P < .04). Major complications occurred in 8% (five of 64) of PTD procedures (none related to the PTD) and 9% (five of 58) PSPMT procedures (not significant). Two devices broke (one during training) with no clinical sequela. The 3-month primary patency rate was 39% (25 of 64) in the PTD group and 40% (23 of 58) in the PSPMT group (not significant). CONCLUSION: The PTD is safe and effective for treating thrombosed hemodialysis access grafts. The technical and long-term success rates are similar to those of PSPMT; procedure times are shorter.

Experience with 100 consecutive central venous access arm ports placed by interventional radiologists.

PURPOSE: This study reports the authors' experience with long-term follow-up of 100 consecutive peripherally inserted, subcutaneous arm ports for central venous access. MATERIALS AND METHODS: One hundred patients with subcutaneous arm ports inserted by interventional radiologists were retrospectively studied. Data were collected from the patients' medical records and from telephone canvassing. Using each insertion period as an observation, the complication rates per 100 catheter days were determined with 95% confidence intervals (CIs). RESULTS: One hundred subcutaneously implanted ports were placed in 98 patients; three devices (three patients) were lost to follow-up, leaving 97 devices in 95 patients. Total exposure time was 23,842 days (mean, 246 days; range, 2-865 days). Seven infectious and two noninfectious complications occurred with seven (7.2%) devices in six patients (6.3%), yielding 0.038 complications per 100 catheter days at risk (95% CI; 0.011-0.069) and 0.029 infections per 100 catheter days at risk (95% CI; 0.008-0.058). A successful clinical outcome was defined as a functional port at removal, time of death, or at study closure (minimum of 6 months of follow-up), which was not removed because of a complication. This successful outcome was achieved in 91 ports (93.8%). Procedural-related complications, defined as those occurring up to 30 days after insertion, occurred in only one port (thrombophlebitis and catheter tip infection-day 9). All other patients received several months of service from their port. Fifteen devices were placed in 13 patients with HIV for 3,486 days, with a total complication rate of 0.11 per 100 catheter days (95% CI; 0.0-0.28), all of which were infections. Devices in HIV-positive patients were associated with higher total complication (20% vs 4.9%) and infection rates (20% vs 3.7%) than devices in patients without HIV infection. This gives a relative risk 8.17 x (P = .04) greater for infectious complications for devices placed in HIV-infected individuals. CONCLUSIONS: Subcutaneous arm ports placed by interventional radiologists are effective for central venous access with excellent functionality (93.8% achieved a successful long-term outcome) and a very low procedural complication rate. Although infections were more frequent in HIV-infected individuals, these devices are associated with a very low incidence of both immediate and long-term complications, including infection, for all patients.

Radiographic detection of single-leg fracture in Björk-Shiley Convexo-Concave prosthetic valves: a phantom model study.

Cineradiography can identify patients with single-leg fractured Björk-Shiley Convexo-Concave valves, although little is known about the sensitivity and specificity of this technique. We evaluated three normal and six (0 microm gap) single-leg fractured Björk-Shiley valves that were placed in a working phantom model. Valves were randomly imaged a total of 33 times and duplicated into a 120-valve series with a 1:9 ratio of abnormal/normal valves. Six reviewers independently graded each valve and demonstrated markedly different rates of identifying the fractured valves. Average sensitivity at the grade that clinically results in valve explanation was 47%. Among the normal valves, a correct identification was made 96% (range 91% to 99%) of the time. Present radiographic technology may have significant difficulty in identifying true single-leg fracture in Björk-Shiley valves with limb separations that are common among clinically explanted valves.

Experimental nonsurgical transcervical sterilization with a custom-designed platinum microcoil.

PURPOSE: Investigation of a technique for nonsurgical female sterilization. MATERIALS AND METHODS: A custom designed platinum microcoil with Dacron fibers was placed unilaterally into a fallopian tube and uterine horn of 10 rabbits after transcervical selective tubal catheterization with use of fluoroscopic guidance. The contralateral uterus and fallopian tube served as controls. After the rabbits were bred, pregnancy was determined by palpation and confirmed at autopsy. Postmortem histopathologic evaluation of uteri and fallopian tubes was performed. RESULTS: Nine of the 10 rabbits became pregnant. None of the animals had embryos on the microcoil side. Nine rabbits had a total of 45 embryos on the control side. One animal failed to become pregnant on either side. The microcoil remained in good position in all 10 rabbits. There was a microcoil-associated, mild inflammatory tissue response in the uteri and fallopian tubes. CONCLUSION: A platinum occlusion microcoil placed in a utero-tubal location has potential as a means for nonsurgical female sterilization.

PIP: At Milton S. Hershey Medical Center in Hershey, Pennsylvania, researchers used fluoroscopy to guide transcervical selective tubal catheterization in order to correctly insert a custom-designed platinum microcoil with Dacron fibers 1.5-6 cm into a fallopian tube and 1.5-5.5 cm into a uterine horn of 10 rabbits. The fallopian tube and uterine horn on the opposite side were the controls. The researchers sacrificed the rabbits to conduct histopathologic examination of the uteri and fallopian tubes in order to determine the presence or absence of embryos. One rabbit had no embryos on either side, even after 4 breeding attempts. Among the remaining 9 rabbits, there were no embryos on the microcoil side and 45 embryos on the control side. The position of the microcoil did not change in any rabbit. The microcoil caused a mild inflammatory tissue response in the uteri and fallopian tubes. Longer-term studies in more animals are necessary to confirm the efficacy and safety of this sterilization method as well as to determine the potential for retrievability of the microcoil and reversibility of the sterilization effect. In conclusion, a uterotubal coil may someday be a safe, effective, minimally invasive means of female sterilization.

Cumulative experience with 1,273 peripherally inserted central catheters at a single institution.

PURPOSE: To compare bedside insertion of peripherally inserted central catheters (PICCs) by specially-trained nurses with insertion by cardiovascular and interventional radiologists. MATERIALS AND METHODS: Nurses performed 327 bedside insertions with a palpatory, through-the-needle technique in 301 patients. Radiologists performed 542 insertions with a venographic-fluoroscopic direct puncture and sheath technique in 354 patients. RESULTS: A total of 869 PICCs were inserted in 655 patients. Compared with the first interval of the study (reported previously), bedside technical success improved from 74% to 82.6%, technical success decreased from 98.6% to 98.2%, and the service interval for a given PICC decreased from 72.7 to 28.1 days (because PICCs were used instead of peripheral intravenous lines). Rates of thrombophlebitis and infection remained low. Device failure continued to be a problem. About 25% of patients needed insertion of more than one PICC to complete therapy. CONCLUSION: Bedside insertion by specially trained nurses is less costly than insertion by radiologists, but radiologists are needed for difficult initial insertions, PICC salvage, and PICC exchange.

Development of a model angiography informed consent form based on a multiinstitutional survey of current forms.

PURPOSE: To develop an informative consent form for angiography that can be read and understood by a patient with an eighth-grade level of education. MATERIALS AND METHODS: Consent forms from 125 medical centers were evaluated with RightWriter 4.0 software. The readability index, a measure of educational grade level needed to understand a document, was determined for each form. Features of forms and discussion of complications were evaluated. A model consent form was developed. RESULTS: Analysis of 27 consent forms revealed a mean readability index of 14.2; to adequately understand the documents, an average of 2.2 years of college were required. Alternatives to the procedure were listed in 14 forms (52%). All consent forms listed potential complications, but only 15 (56%) identified specific numeric risks, and attempts to classify complications according to severity were made in only five (18%). CONCLUSION: An angiography consent form has been developed that can be understood with an eight-grade level of education. It should allow patients to more easily understand the procedure and its risks, benefits, and alternatives. It remains the obligation of the physician to tailor the discussion for each procedure to meet the needs of each patient.