The Randomized Freeway Stent Study: Drug-Eluting Balloons Outperform Standard Balloon Angioplasty for Postdilatation of Nitinol Stents in the SFA and PI Segment.

PURPOSE: The prospective randomized multicenter Freeway study evaluated the possible hemodynamic and clinical benefits of primary stent insertion followed by percutaneous transluminal angioplasty (PTA) with drug-eluting balloons (DEB) over post-stent insertion PTA with standard balloons in the treatment of symptomatic femoropopliteal arteriosclerotic lesions. METHODS: In total, 204 patients in 13 centers in Germany and Austria were enrolled and randomized to primary stenting followed by either FREEWAY™ drug-eluting balloon or standard PTA balloon angioplasty. The primary endpoint was the rate of clinically driven target lesion revascularization (TLR) at 6 months; the secondary endpoints include TLR rate at 12 months and primary patency, shift in Rutherford classification, ankle-brachial index (ABI) and major adverse events (MAE) at 6 and 12 months. Lesion characteristics and vessel patency were analyzed by an independent and blinded corelab. RESULTS: At 6-month and 12-month follow-up, TLR rate was lower in the DEB arm compared to standard PTA but did not reach statistical significance (4.1% vs. 9.0% p = 0.234 and 7.9% vs. 17.7% p = 0.064, respectively). Primary patency was significantly better for patients treated with the DEB at 6 months (90.3% vs. 69.8% p = 0.001) and 12 months (77.4% vs. 61.0% p = 0.027). Improvement in Rutherford classifications was likewise significantly better for patients in the DEB group at 6 (94.9% vs. 84.3% p = 0.027) and 12 months (95.5% vs. 79.9% p = 0.003). The percentage of patients with an improved ABI of 1.0-1.2 was significantly higher in the DEB group compared to the PTA group at 6 months (55.3% vs. 35.3%; p = 0.015) but without significant difference at 12 months (48.2% vs. 32.9%; p = 0.055). At 6 months, rate of major adverse events (MAE) was 1% in both arms, and at 12 months 2.2% for the DEB and 3.8% for the PTA group. CONCLUSION: The Freeway Stent Study shows that the usage of DEB as a restenosis prophylaxis seems to be safe and feasible. The 12-month follow-up results give a clear sign in favor of the DEB group.

Patient radiation dose in percutaneous biliary interventions: recommendations for DRLs on the basis of a multicentre study.

OBJECTIVE: Percutaneous biliary interventions (PBIs) can be associated with a high patient radiation dose, which can be reduced when national diagnostic reference levels (DRLs) are kept in mind. The aim of this multicentre study was to investigate patient radiation exposure in different percutaneous biliary interventions, in order to recommend national DRLs. METHODS: A questionnaire asking for the dose area product (DAP) and the fluoroscopy time (FT) in different PBIs with ultrasound- or fluoroscopy-guided bile duct punctures was sent to 200 advanced care hospitals. Recommended national DRLs are set at the 75th percentile of all DAPs. RESULTS: Twenty-three facilities (9 interventional radiology depts. and 14 gastroenterology depts.) returned the questionnaire (12%). Five hundred sixty-five PBIs with 19 different interventions were included in the analysis. DAPs (range 4-21,510 cGy·cm2) and FTs (range 0.07-180.33 min) varied substantially depending on the centre and type of PBI. The DAPs of initial PBIs were significantly (p < 0.0001) higher (median 2162 cGy·cm2) than those of follow-up PBIs (median 464 cGy·cm2). There was no significant difference between initial PBIs with ultrasound-guided bile duct puncture (2162 cGy·cm2) and initial PBIs with fluoroscopy-guided bile duct puncture (2132 cGy·cm2) (p = 0.85). FT varied substantially (0.07-180.33 min). CONCLUSIONS: DAPs and FTs in percutaneous biliary interventions showed substantial variations depending on the centre and the type of PBI. PBI with US-guided bile duct puncture did not reduce DAP, when compared to PBI with fluoroscopy-guided bile duct puncture. National DRLs of 4300 cGy·cm2 for initial PBIs and 1400 cGy·cm2 for follow-up PBIs are recommended. KEY POINTS: • DAPs and FTs in percutaneous biliary interventions showed substantial variations depending on the centre and the type of PBI. • PBI with US-guided bile duct puncture did not reduce DAP when compared to PBI with fluoroscopy-guided bile duct puncture. • DRLs of 4300 cGy·cm2for initial PBIs (establishing a transhepatic tract) and 1400 cGy·cm2for follow-up PBIs (transhepatic tract already established) are recommended.

Case study of hepatic radiofrequency ablation causing a systemic inflammatory response under total intravenous anesthesia.

OBJECTIVE: To investigate the effects of hepatic radiofrequency ablation (RFA) in patients with malignant liver disease with respect to inflammation activation and stress response. MATERIALS AND METHODS: In an observational trial, we investigated the physiologic parameters of 17 patients (20 interventions) who underwent percutaneous RFA under general anesthesia after applying total intravenous anesthesia. TNFα, IL-6, IL-8, IL-10, adrenaline and noradrenaline, liver enzymes, lactate and creatine kinase were determined pre-interventionally after induction of anesthesia (T1), 90 minutes after initiation of RFA (T2), immediately after the conclusion of the procedure (T3), and 24 hours after the procedure (T4). RESULTS: A significant increase in body temperature (p < 0.001), and mean arterial pressure (p = 0.001) were measured intraoperatively (T2) and the day after the procedure (T4). Increased levels of IL-6 were measured at T3 and T4 (p = 0.001). IL-10 increased immediately after the procedure (T3; p = 0.007). IL-6 levels correlated well with the total energy applied (r = 0.837). Significant increases in the levels of adrenaline and noradrenaline were present at T3 and T4 (p < 0.001). The RFA-induced destruction of hepatic tissue was associated with increased levels of AST, ALT, GLDH and LDH. CONCLUSION: Percutaneous RFA of hepatic malignancies causes an inflammatory and endocrine activation, similar to the systemic inflammatory response syndrome. These effects have to be taken in account when dealing with patients susceptible to sepsis or multi-organ failure.

Functional cervical MRI within the scope of whiplash injuries: presentation of a new motion device for the cervical spine.

PURPOSE: Frequently following a whiplash injury of the cervical spine, patients suffer from persistent pain symptoms. The MRI will in some of these cases show changes consistent with disk pathology or spinal stenosis, although in most instances the imaging studies will offer no adequate explanation for the described symptoms. The goal of our research was to develop and test a new MRI compatible device that will allow functional imaging of the cervical spine. METHODS: A total of 30 patients with whiplash injuries were evaluated during the first 6 weeks following trauma with the functional MRI. The examination was carried out with a T2-weighted turbo spin-echo sequence utilizing a new apparatus consisting of an inflatable air bag contained in a Plexiglas housing. Thanks to a valve placed outside of the examination room, it was possible to individually regulate the amount of air used to fill the pillow, thereby obtaining a full range of motion between flexion and extension. RESULTS: In 25 cases no pathology was found during this examination. Two patients presented with scarring of the alar ligaments, indicative of a traumatic lesion. In two other instances the images in reclination revealed a bulging disk, while in one case a widening of the disk space was found as a sign for a rupture of the anterior longitudinal ligament. CONCLUSION: Our study was able to demonstrate the applicability of the new functional testing device, which permits a standardized, continuous and dynamic evaluation of the cervical spine in a closed MRI.

Molecular magnetic resonance imaging of deep vein thrombosis using a fibrin-targeted contrast agent: a feasibility study.

PURPOSE: To evaluate the value of a fibrin-specific MR contrast agent (EP-2104R; EPIX Pharmaceuticals) for detection of deep vein thrombosis (DVT) and monitoring of percutaneous intervention for treatment. MATERIALS AND METHODS: In 6 domestic swine, DVT was induced in an iliac/femoral vein using an occlusion-balloon catheter and subsequent injection of thrombin. The occluded vessels were recanalized by mechanical thrombectomy using a Fogarty catheter and an Arrow rotating thrombectomy device. Magnetic resonance imaging of the pelvis and lung was repeated 4 times (before and after DVT induction, after contrast agent administration, and after intervention) using a 1.5-T whole-body XMR system (ACS-NT, Philips Medical Systems, Best, NL). The visualization of the thrombi and contrast-to-noise ratio (CNR) was assessed. RESULTS: EP-2104R allowed selective visualization of thrombi with accurate determination of the extent of DVT with high contrast (CNR: 65.3 +/- 17.2). After intervention, dislodged thrombus fragments were selectively visualized in the lung (CNR: 27.9 +/- 9.3). CONCLUSIONS: Molecular magnetic resonance imaging using fibrin-specific MR contrast agent EP-2104R allowed for selective visualization of DVT and monitoring of percutaneous intervention.

A porcine deep vein thrombosis model for magnetic resonance-guided monitoring of different thrombectomy procedures.

PURPOSE: To establish a porcine model of deep iliac vein thrombosis, which allows monitoring of thrombectomy and thrombolytic procedures by magnetic resonance imaging (MRI). MATERIALS AND METHODS: Deep iliac vein thrombosis was induced in 12 domestic swine using an occlusion-balloon catheter and subsequent injection of thrombin distal to the occluded vessel site. Thrombosis induction was successfully achieved in all animals after 1 hour as verified by MRI. In addition, x-ray fluoroscopy was performed for comparison. Subsequently, thrombectomy was performed using a Fogarty catheter, an Arrow-Trerotola percutaneous thrombolytic device as well as electrical discharge-induced shock waves. The latter procedure was carried out with and without additional administration of Actilyse. MRI and x-ray fluoroscopy were repeated to monitor therapy. RESULTS: After successful thrombosis induction within the deep iliac veins in all cases, thrombus material could be completely removed using the Fogarty catheter and the Arrow-Trerotola percutaneous thrombolytic device, whereas electrical discharge-induced shock wave failed to recanalize the occluded vessel even if additional Actilyse was administered. The actual burden of thrombotic material could be reliably visualized using MRI. CONCLUSIONS: A porcine model of deep iliac vein thrombosis model is presented, which permits reliable visualization of thrombotic material. This model might be a useful tool to compare different thrombectomy devices or to evaluate the effectiveness of new thrombolytic approaches.

Radiofrequency ablation of osteoid osteoma: initial results with a bipolar ablation device.

PURPOSE: To report the initial results with percutaneous radiofrequency (RF) ablation of osteoid osteomas with a bipolar ablation device. MATERIALS AND METHODS: Twelve patients (seven male patients and five female patients; mean age, 17.3 years; age range, 6-36 y) with clinically and radiologically suspected osteoid osteoma were treated with computed tomography-guided percutaneous bipolar RF ablation. The procedure was performed with the patients under general anesthesia. After localization of the nidus, an 11-gauge hollow drill was introduced into the nidus through a 9-F introducer sheath. A bipolar 18-gauge RF probe with a 9-mm active tip was inserted through the introducer sheath and connected to the RF generator. Energy application was started at 2 W and subsequently increased to a maximum of 5 W. The procedure was terminated if a resistance of 900 Omega was reached. RESULTS: Mean duration of energy deposition was 8.3 +/- 4.0 minutes, with a mean energy application of 1.8 +/- 2.9 kJ (range, 0.3 - 7 kJ). In one patient, the intervention had to be repeated twice to achieve total pain relief. Eleven of 12 patients (92%) remained free of symptoms at a follow-up time of 15.1 +/- 9.5 months (range, 5 - 31 months). One patient had recurrence of pain 16 months after the procedure and was treated surgically. No complications occurred. Patients resumed normal activity within 24 hours. CONCLUSIONS: Percutaneous bipolar RF ablation is an efficient and safe treatment of osteoid osteoma. Short-term efficacy of bipolar RF ablation may rival the results of monopolar RF ablation. Further studies are needed to address the long-term efficacy of this technique.

Radiofrequency ablation of renal tumors.

Percutaneous thermal ablation is increasingly applied in the therapy of renal tumors. Various techniques are available, allowing a safe and accurate therapy of renal tumors either using hyperthermia such as radiofrequency ablation (RFA), laser-induced thermotherapy (LITT) and microwave ablation (MW) or by hypothermia (cryoablation). As thermal ablation is a minimally invasive and nephron-sparing procedure, it is ideally suited for patients with a single kidney, multiple tumors or contraindications for resective surgery. Although cryotherapy is the most extensively studied technique, RFA has become the most accepted thermal ablation technique over the last years. Modern RFA probes allow ablation volumes between 2 and 5 cm in diameter. A major advantage of RFA is the ability to avoid tract bleeding and tumor seeding by coagulating the puncture channel during RF probe withdrawal. The increasing number of clinical reports on RFA of the kidney show the promising potential of renal RFA for minimally invasive tumor treatment. Due to its technical benefits, RFA seems to be advantageous when compared to cryoablation or laser ablation. However, there are no long-term follow-up or comparative data proving an equal effectiveness to surgery.

MR-guided radiofrequency ablation of hepatic malignancies at 1.5 T: initial results.

PURPOSE: To assess the feasibility of magnetic resonance (MR)-guided radiofrequency ablation (RFA) of hepatic malignancies using a high-field MR scanner. MATERIALS AND METHODS: A total of 10 patients with 14 primary (N = 1) or secondary (N = 13) hepatic malignancies underwent MR-guided RFA using a closed-bore 1.5 T MR scanner. Lesion diameters ranged from 2.0 cm to 4.7 cm. RFA was performed using a 200-W generator in combination with a 3.5-cm LeVeen electrode applying a standardized energy protocol. RESULTS: RFA was technically feasible in all patients. Necrosis diameter ranged from 2.5 cm to 6.8 cm. The mean follow-up period is 12.2 (1-18) months. In nine out of 10 patients, local tumor control was achieved. For this purpose, a second CT-guided RFA was required in two patients. In four patients, multifocal hepatic tumor progression occurred, with the treated lesion remaining tumor-free in three of these patients. Two patients showed extrahepatic tumor progression. Four patients remained tumor-free. No major complications occurred. CONCLUSION: MR-guided RFA of hepatic malignancies in a closed-bore high-field MR scanner is technically feasible and safe. It can be advantageous in locations considered unfavorable for CT-guided puncture or in patients in which iodinated contrast material is contraindicated.

Noninvasive extracorporeal thrombolysis using electrical discharge-induced shock waves: in vitro experiments.

RATIONALE AND OBJECTIVES: Many thrombectomy approaches have been developed for the treatment of venous thrombosis; however, no reference standard exists at this time. The aim of this study was to evaluate the efficacy of the transcutaneous application of electrical discharge-induced shock waves for thrombolysis in an in vitro model. METHODS: Shock waves were applied on a thrombus positioned in a plasma-containing silicon tube using 2 different energy flux densities (0.53 and 2.26 mJ/mm). Depending upon the specific experiment, the thrombus was slightly moved to mimic pulsatory motions or/and additional Actilyse was added. Plasma samples were taken to determine the d-dimers before and after the application of shock waves. RESULTS: Energy of 0.53 mJ/mm was insufficient for thrombolysis whereas the energy of 2.26 mJ/mm yielded a removal rate of up to 76.4% when the thrombus was slightly moved during the procedure. The amount of d-dimers correlated well with the addition of Actilyse. However, this did not affect the removal rate significantly. CONCLUSION: The results demonstrate the potential of electrical discharge-induced shock waves for thrombolysis.

Regional thermoablation of local or metastatic renal cell carcinoma.

The objective of the study was to elucidate thermal based ablation techniques for local tumor control. Seven lesions of renal cell carcinoma (2 renal, 1 adrenal, 2 muscle, 1 hepatic, 1 bone) were treated under local (n=2) or general (n=6) anaesthesia with percutaneous cryoablation (CRA): CryoHit device or radiofrequency (RF) ablation (RFA): RF 3000). Treatment was palliative in 4 patients with progression after systemic therapies, and with curative intention in one organ confined tumor (patient with active HCV and HIV infection). Mean power for RFA was 165 watts. Duration of treatments was 10-91 min. No bleeding or urinary leakage was observed; no drainage or indwelling catheters necessary. Pain relief was sufficiently achieved by tramadol and novaminesulfon. Inpatient period on average was 4.25 days. CRA led to complete tumor destruction (CTD) of an adrenal mass (time to progression, 15+ months) and partial tumor destruction (PTD) of a lumbar lesion (19 months); RFA resulted in CTD of 3 lesions (liver, 9+ months; kidney, 1+, 13+ months) and PTD in 2 lesions (muscle and bone, 3 months). In conclusion, it was found that CRA and RFA are safe and effective methods to destroy metastatic RCC. Such minimal invasive techniques are favorable for palliative treatment (low performance status, surgical preconditions) and in conjunction with immunochemotherapy; A decreased risk of bleeding, the shorter duration of hospitalization and a faster recovery of the patient encourage minimal invasive percutaneous thermal based therapies due to life-quality and economic aspects. Treatment of primary renal cell carcinoma is currently under investigation.