High-Dose Intracoronary Irradiation after De Novo Stent Implantation

PURPOSE: This randomized study was designed to compare the efficacy of high-dose coronary beta-radiation after intravascular ultrasound-(IVUS-)guided direct stenting with sham treatment in patients with de novo lesions. PATIENTS AND METHODS: 32 patients were enrolled in the study protocol. Following angioplasty procedure, intracoronary brachytherapy was performed with the Novoste Beta-Cath System. The prescribed dose was 24 Gy referred to the lamina elastica externa. Quantitative coronary angiography and IVUS were performed to analyze the treated coronary vessel. RESULTS: Angiographic results revealed a significantly smaller minimal lumen diameter compared with the pos-tprocedural minimal lumen diameter within the stented segment (p = 0.004) in the nonirradiated group. The same significant result was observed in the injured segment of the nonirradiated patients (p = 0.011). The IVUS data revealed a significant increase of the plaque volume after 8 months in the nonirradiated group compared to the post-procedural value (irradiated 5.41 +/- 8.83 mm(3) vs. nonirradiated 21.11 +/- 16.08 mm(3); p = 0.001). Late luminal loss was significantly greater in the nonirradiated group (p = 0.004). The primary clinical endpoint (death, myocardial infarction, repeat target lesion revascularization, percutaneous revascularization, coronary artery bypass surgery) was reached by seven irradiated (33.3%) and four (18.2%) nonirradiated patients (p = 0.623). Late stent thrombosis was observed in one irradiated patient. CONCLUSION: The EVEREST trial has demonstrated the feasibility of high-dose intracoronary brachytherapy in de novo coronary lesions. There is a significant reduction of neointimal proliferation within the stented segment. Nevertheless, this benefit is vitiated by an increase of restenotic lesions outside the stent segment.     

Enhanced external counterpulsation: a new technique to augment renal function in liver cirrhosis.

BACKGROUND: Advanced liver cirrhosis is characterized by cardiovascular changes, such as low arterial blood pressure, peripheral vasodilation and renal vasoconstriction. As a consequence, renal hypoperfusion, impaired diuresis and natriuresis and eventual hepatorenal syndrome may ensue. Previous studies using head-out water immersion to increase central blood volume have demonstrated the functional nature of the renal abnormalities. Enhanced external counterpulsation (EECP) is a new non-invasive cardiac assist device to augment diastolic blood pressure by electrocardiogram-triggered diastolic inflation and deflation of cuffs wrapped around the lower extremities. We investigated whether EECP would improve renal dysfunction of liver cirrhosis. METHODS: Twelve healthy controls and 19 patients with liver cirrhosis were observed during 2 h of baseline followed by 2 h of EECP. The following parameters of renal and cardiovascular function were measured: renal plasma flow by para-aminohippurate clearance, glomerular filtration rate (GFR) by inulin clearance, urine flow rate, urinary excretion rates of sodium and chloride, mean arterial blood pressure (MAP), renal vascular resistance (RVR) and plasma concentrations of renin, atrial natriuretic peptide (ANP), endothelin-1, antidiuretic hormone, epinephrine and N-epinephrine. RESULTS: EECP was well tolerated by healthy controls and cirrhotic patients alike. EECP increased MAP (cirrhotic patients: from 74+/-18 to 88+/-20 mmHg, P<0.01; controls: from 89+/-8 to 94+/-5 mmHg, P = NS) and ANP (cirrhotic patients: from 23+/-18 to 30+/-20 ng/l, P<0.05; controls: from 11+/-4 to 16+/-5 ng/l, P<0.01). The plasma renin concentration decreased (cirrhotic patients: from 98+/-98 to 58+/-57 ng/l, P<0.01; controls: from 4.6+/-1.6 to 3.4+/-1.1 ng/l, P<0.01). This was associated with improvement of the urinary flow rate (cirrhotic patients: from 3.6+/-1.8 to 4.6+/-0.7 ml/min, P<0.05; controls: from 1.8+/-1.5 to 2.8+/-1.9 ml/min, P<0.05), as well as of the sodium and chloride excretion rates in both groups. However, in contrast to healthy controls, GFR and renal plasma flow in cirrhotic patients failed to rise significantly. Renal vascular resistance fell numerically in healthy controls (68+/-5 vs 55+/-4 mmHg . min/l; P = NS). In contrast, RVR showed a significant increase by approximately 20% in cirrhosis (67+/-4 vs 80+/-8 mmHg . min/l; P<0.05). Endothelin-1 levels fell in controls (0.38+/-0.42 vs 0.31+/-0.35; P<0.05), whereas they remained statistically unchanged in cirrhotic patients. Epinephrine, N-epinephrine and vasopressin were not altered by EECP in either group. CONCLUSIONS: EECP is an effective procedure to augment renal excretory function in healthy volunteers as well as in patients with cirrhosis. In healthy volunteers, GFR and renal plasma flow increased during EECP. In contrast, these parameters remained unchanged in the patients and their renal vascular resistance increased during EECP. Therefore, EECP improves diuresis, but does not influence the vasoconstrictive dysregulation of the kidneys in liver cirrhosis.     

On the Formation Mechanism of Column Damage Within Modular Taper Junctions

BackgroundColumn damage is a unique degradation pattern observed in cobalt-chromium-molybdenum (CoCrMo) femoral head taper surfaces that resemble column-like troughs in the proximal-distal direction. We investigate the metallurgical origin of this phenomenon.MethodsThirty-two severely damaged CoCrMo femoral head retrievals from 7 different manufacturers were investigated for the presence of column damage and chemical inhomogeneities within the alloy microstructure via metallographic evaluation of samples sectioned off from the femoral heads.ResultsColumn damage was found to affect 37.5% of the CoCrMo femoral heads in this study. All the column-damaged femoral heads exhibited chemical inhomogeneities within their microstructures, which comprised of regions enriched or depleted in molybdenum and chromium. Column damage appears as a dissolution of the entire surface with preferential corrosion along the molybdenum and chromium depleted regions.ConclusionMolybdenum and chromium depleted zones serve as initiation sites for in vivo corrosion of the taper surface. Through crevice corrosion, the degradation spreads to the adjacent non-compositionally depleted areas of the alloy as well. Future improved alloy and processing recipes are required to ensure no chemical inhomogeneity due to segregation of solute elements are present in CoCrMo femoral heads.     

A Farewell from the Editor

CardioVascular and Interventional Radiology -     

Characterization of the grinding behaviour in a single particle impact device: Studies on pharmaceutical powders

The grinding behaviour of different materials can be described by the two material parameters f_Mat and W_m,min [Vogel, L., Peukert, W., 2003. Breakage behaviour of different materials—construction of a mastercurve for the breakage probability. Powder Technol. 129, 101–110]. f_Mat describes the resistance of particulate material against fracture in impact comminution, W_m,min characterizes the specific energy which a particle can take up without comminution. The material parameters are determined experimentally by single particle impact tests. This concept is also applicable to pharmaceutical powders, as will be shown in this work. A device is presented for the characterization of particles with sizes down to a few 10 μm. Particles are dispersed and accelerated in an air stream which is flowing against an impact plate. The impact velocity is controlled by the air flow. An LDA system enables the measurement of particle velocities. The results obtained with this jet mill are in accordance to those obtained from another single particle impact device used by Vogel and Peukert, in which the influence of fluid flow is completely avoided. Since the new device is especially designed for finer powders, it will allow a more detailed analysis of the material parameters at smaller particle sizes. Additionally, a new analysis method has been developed in order to determine the breakage probability not from sieve analysis but from laser light diffraction (LLD) data by using a population balance.     

Drug-Eluting Stent Versus Drug-Coated Balloon Revascularization in Patients With Femoropopliteal Arterial Disease

Background

Randomized trials of drug-eluting stents (DES) and drug-coated balloons (DCB) for femoropopliteal interventions reported superior patency rates for both strategies compared to standard balloon angioplasty. To date, head-to-head comparisons are missing.

Effect of two different neuroprotection systems on microembolization during carotid artery stenting

OBJECTIVES: This study sought to compare the efficacy of two different cerebral protection systems for the prevention of embolization during carotid artery stenting (CAS) using a transcranial Doppler (TCD) monitoring with the detection of microembolic signals (MES). BACKGROUND: Despite the introduction of cerebral protection systems, neurologic complications during CAS cannot completely be prevented. Transcranial Doppler and detection of MES may aid in assessing the efficacy of different neuroprotection systems. METHODS: A total of 42 patients with internal carotid artery stenoses were treated by CAS using either a filter (E.P.I. FilterWire, Boston Scientific Corp., Santa Clara, California) (n = 21) or a proximal endovascular clamping device (MO.MA system, Invatec s.r.l., Roncadelle, Italy) (n = 21). Microembolic signal counts were compared during five phases: placement of the protection device, passage of the stenosis, stent deployment, balloon dilation, and retrieval of the protection device. RESULTS: There were no significant differences in clinical or angiographic outcomes between the two groups. Compared to the filter device, the MO.MA system significantly reduced MES counts during the procedural phases of wire passage of the stenosis, stent deployment, balloon dilation, and in total (MES counts for the filter device were 25 +/- 22, 73 +/- 49, 70 +/- 31, and 196 +/- 84 during the three phases and in total, MES counts for the MO.MA system were 1.8 +/- 3.2, 11 +/- 19, 12 +/- 21, and 57 +/- 41, respectively; p < 0.0001). CONCLUSIONS: In comparison to a filter device the MO.MA system led to significantly lower MES counts during CAS. The detection of MES by TCD may facilitate the evaluation and comparison of different neuroprotection systems.