Value of covered stents to improve patency of long-segment SFA revascularization.

Endovascular treatment has become first-line approach for revascularization of long and complex femoropopliteal lesions in many centers. This development urges the need for endovascular approaches with a sustainable success in terms of patency. In several recently published trials the Viabahn® endoprosthesis by Gore (W.L. Gore Inc, Flagstaff, AZ, USA) has shown promising patency rates comparable or even better than traditional surgical bypass procedures with prosthetic material.

Combination of mechanical atherectomy and drug-eluting balloons for femoropopliteal in-stent restenosis.

Mechanical atherectomy for instent restenosis (ISR) seems to be limited by a low patency rate. This might be due to the mechanical trauma that induces an inflammatory response leading to recurrent ISR. Addition of drug eluting balloon angioplasty could overcome these challenges while preserving the advantages of a better acute result. Due to lack of clinical data combination of atherectomy and DEB remains an experimental procedure for ISR treatment.

Acute and long-term outcome of Silverhawk assisted atherectomy for femoro-popliteal lesions according the TASC II classification: a single-center experience.

BACKGROUND: Directional atherectomy (DA) has become popular in some centers to remove atherosclerotic plaques in femoro-popliteal lesions. Although immediate and also short - term outcome data are promising, solid long-term data are warranted to justify the widespread use in daily practice. PATIENTS AND METHODS: In this prospective study de novo and restenotic lesions of the femoro-popliteal segments were treated with the Silverhawk device. 161 consecutive patients (164 lesions) with peripheral artery disease (PAD) Rutherford classes 2 to 5 were included from June 2002 to October 2004 and October 2006 to June 2007 (59 % male, mean age 67 +/- 11 years, range 40 to 88) and the outcome analyzed according to the TASC II classification. RESULTS: DA alone was performed successfully in 28 % (n = 46), adjunctive balloon angioplasty in 65 % (n = 107) and stenting in 7 % (n = 11). The overall technical success rate was 76 % (124 / 164) and the procedural success rate 95 % (154 / 164). At 12 months primary patency rate was 61 % (85 / 140) and the secondary patency rate was 75 % (105 / 140) in the entire cohort, being less favourable in TASC D compared to TASC A to C lesions (p = 0.034 and p < 0.001, respectively). Furthermore the restenosis rate differed trendwise (p = 0.06) between de novo and restenotic lesions. Changes in the ABI and the Rutherford classes were significantly in favour of TASC A to C lesions compared to TASC D after 12 months (p = 0.004). The event free survival (MI, TIA, or restenosis) was 48 % at 12 months and 38.5 % at 24 months. Predictor for restenosis in the multivariable analysis was only male gender (p=0.04). CONCLUSIONS: The results in TASC D lesions are inferior to those in the lesser stages. DA of femoro-popliteal arteries leads shows a trend to better long-term technical and clinical outcome in de novo lesions compared to restenotic lesions.

Percutaneous iliac vein recanalization 17 years after thrombotic occlusion.

Persistent venous outflow obstruction of the iliac veins is one of the mechanisms that seem to portend the greatest risk for late development of severe complications. We report the case of a 42-year-old male with postthrombotic occlusion of the left external iliac artery since the age of 25. We managed to recanalize the obstructed vessel and establish a good flow into the inferior vena cava by venous stenting. After successful intervention the patient reported instant symptom relief and was free from venous claudication and leg heaviness at the 6 month follow-up examination. Even after long history of postthrombotic syndrome, venous stenting can be an option for patients with chronic outflow obstructions of the iliac veins.

Long term outcome after balloon angioplasty and stenting of subclavian artery obstruction: a single centre experience.

INTRODUCTION: Percutaneous transluminal angioplasty is an accepted and successful treatment strategy in obstructive disease of the subclavian artery. The purpose of this study was to evaluate the technical and clinical long-term outcome following endovascular therapy. PATIENTS AND METHODS: We retrospectively analyzed 99 patients (mean age of 65 +/- 10 years) with 100 interventions of the subclavian arteries and the brachiocephalic trunk with different aetiologies [atherosclerosis (90%); Takayasu's arteritis (5%); thromboembolism (2%); external compression (1%); iatrogenic dissection (1%) and occlusion after graft implantation in type B dissection (1%)]. RESULTS: Primary success rate was 97% (100% for stenoses and 90% for total occlusions). Treatment modalities included balloon angioplasty (PTA) alone (16%), stent implantation (78%), rotational thrombectomy (2%) and atherectomy (1%). The primary 1-year patency rate of the whole study cohort was 87% being not significantly lower after PTA (75%) compared to stent assisted angioplasty (89%). After thrombectomy and atherectomy no relevant restenosis were found. Multivariable analysis of 1-year restenosis-free survival revealed younger age (p = 0.03) and stenting (p = 0.04) as independent predictor. The blood pressure difference between both limbs at baseline was 42 +/- 24 mmHg and dropped to 10 +/- 14 mmHg after the intervention and 15 +/- 20 mmHg after 12 months, respectively (p = 0.01). CONCLUSIONS: Endovascular therapy of subclavian artery obstructions of various aetiologies offers good acute success rates even in total occlusions. Long-term patency rate is in favour of stent placement.

Properties and function of KCNQ1 K+ channels isolated from the rectal gland of Squalus acanthias.

KCNQ1 (KVLQT1) K+ channels play an important role during electrolyte secretion in airways and colon. KCNQ1 was cloned recently from NaCl-secreting shark rectal glands. Here we study the properties and regulation of the cloned sKVLQT1 expressed in Xenopus oocytes and Chinese hamster ovary (CHO) cells and compare the results with those obtained from in vitro perfused rectal gland tubules (RGT). The expression of sKCNQ1 induced voltage-dependent, delayed activated K+ currents, which were augmented by an increase in intracellular cAMP and Ca2+. The chromanol derivatives 293B and 526B potently inhibited sKCNQ1 expressed in oocytes and CHO cells, but had little effect on RGT electrolyte transport. Short-circuit currents in RGT were activated by alkalinization and were decreased by acidification. In CHO cells an alkaline pH activated and an acidic pH inhibited 293B-sensitive KCNQ1 currents. Noise analysis of the cell-attached basolateral membrane of RGT indicated the presence of low-conductance (<3 pS) K+ channels, in parallel with other K+ channels. sKCNQ1 generated similar small-conductance K+ channels upon expression in CHO cells and Xenopus oocytes. The results suggest the presence of low-conductance KCNQ1 K+ channels in RGT, which are probably regulated by changes in intracellular cAMP, Ca2+ and pH.

Carbachol activates a K+ channel of very small conductance in the basolateral membrane of rat pancreatic acinar cells.

Secretion of Cl- requires the presence of a K+ conductance to hyperpolarize the cell, and to provide the driving force for Cl- exit via luminal Cl- channels. In the exocrine pancreas Cl- secretion is mediated by an increase in cytosolic Ca2+ ([Ca2+]i). Two types of Ca2+-activated K+ channels could be shown in pancreatic acinar cells of different species. However, there are no data on Ca2+-activated K+ channels in rat pancreatic acini. Here we examine the basolateral K+ conductance of freshly isolated rat pancreatic acinar cells in cell-attached and cell-excised patch-clamp experiments. Addition of carbachol (CCH, 1 micromol/l) to the bath led to the activation of very small conductance K+ channels in cell-attached patches (n=27), producing a noisy macroscopic outward current. The respective outward conductance increased significantly by a factor of 2.1+/-0.1 (n=27). Noise analysis revealed a Lorentzian noise component with a corner frequency (f(c)) of 30.3+/-3.5 Hz (n=19), consistent with channel activity in these patches. The estimated single-channel conductance was 1.5+/-0.4 pS (n=19). In cell-excised patches (inside out) from cells previously stimulated with CCH, channel activity was only observed in the presence of K+ in the bath solution. Under these conditions f(c) was 47.6+/-11.9 Hz (estimated single-channel conductance 1.1+/-0.2 pS, n=20). The current/voltage relationship of the noise showed weak inward rectification and the reversal potential shifted towards E(K+) when Na+ in the bath was replaced by K+. Channel activity in cell-excised patches was slightly reduced by 10 mmol/l Ba2+ (23.6+/-2.1% of the total outward current) and was completely absent when K+ in the bath was replaced by Na+. Reduction of the [Ca2+]i from 1 mmol/l to 1 micromol/l in cell-excised experiments decreased the current by 52.3+/-12.3% (n=5). Expression of K(v)LQT1, one of the possible candidates for a small-conductance K+ channel in rat pancreatic acinar cells, was shown by reverse transcriptase polymerase chain reaction (RT-PCR). In fact, a K(V)LQT-blocker (chromanol 293B) reduced channel activity in seven excised patches. These data suggest that CCH activates very small conductance K+ channels in rat pancreatic acinar cells, most likely via an increase in [Ca2+]i.