Feasibility of Percutaneous Ultrasound Guided Intervention with Direct Access in Failing Infrainguinal Vein Bypass Grafts.

BACKGROUND: Patients with infrainguinal venous bypass grafts are at risk of graft stenosis leading to thrombosis and failure of the graft conduit. When primary assisted reintervention is needed, a common first choice of treatment is percutaneous angioplasty using fluoroscopy and digital subtraction angiography (DSA). We investigated whether percutaneous ultrasound-guided intervention (PUSGI) is feasible for such endovascular reinterventions. METHODS: In this retrospective observational study (feasibility study), we included patients with ultrasound evidence of significant stenosis in below-the-knee vein grafts in the lower extremities. Inclusion period was 18 months. Reinterventions were disrupted by performing PUSGI in between traditional DSA. Perioperative success was defined as no sign of residual stenosis, stenosis at the access point in the vein, or need for further fluoroscopy guided intervention. Patient follow-up was conducted 6 weeks after the intervention. Patency of the procedure was defined as no disease recurrence or signs of ultrasonographic restenosis at follow-up. RESULTS: PUSGI was performed in 17 patients referred for reintervention with imminent failing grafts (12 men, 5 women, age range 52-82 years). PUSGI alone was performed successfully in 10 out of 17 patients (59%). The remaining 7 patients underwent successful revascularization with PUSGI in combination with DSA-guided angioplasty. Periprocedural complications occurred in 4 patients. Two of 17 patients had occluded grafts at 6 weeks of follow-up. No PUSGI access site stenoses in grafts were observed. CONCLUSIONS: Percutaneous ultrasound-guided reintervention in peripheral vein bypass disease is feasible for selected patients. The study provides insight to qualitative criteria of eligibility for PUSGI in such reinterventions with direct conduit access.

Flow Complexity Estimation in Dysfunctional Arteriovenous Dialysis Fistulas using Vector Flow Imaging.

Non-invasive assessment is preferred for monitoring arteriovenous dialysis fistulas (AVFs). Vector concentration assesses flow complexity, which may correlate with stenosis severity. We determined whether vector concentration could assess stenosis severity in dysfunctional AVFs. Vector concentration was estimated in four stenotic phantoms at different pulse repetition frequencies. Spectral Doppler peak velocity and vector concentration were measured in 12 patients with dysfunctional AVFs. Additionally, 5 patients underwent digital subtraction angiography (DSA). In phantoms, vector concentration exhibited an inverse relationship with stenosis severity and was less affected by aliasing in severe stenoses. In nine stenoses of 5 patients undergoing DSA, vector concentration correlated strongly with stenosis severity (first stenosis: r = -0.73, p = 0.04; other stenoses; r = -0.69, p = 0.02) and mid-stenotic diameter (first stenosis: r = 0.87, p = 0.006; other stenoses: r = 0.70, p = 0.02) as opposed to peak velocities (p > 0.05). Vector concentration is less affected by aliasing in severe stenoses and correlates with DSA in patients with dysfunctional AVF.

Gigantic Ruptured Aneurysm of the Gastroduodenal Artery Successfully Treated by Coiling.

INTRODUCTION: Visceral aneurysms are rare and a life threatening condition in the case of rupture. REPORT: A 78 year old woman presented with sudden brief loss of consciousness and complained of abdominal tenderness on examination. Computed tomography revealed a gigantic 100 × 130 × 200 mm ruptured true aneurysm of the gastroduodenal artery, which was successfully treated by endovascular coiling. Post-operative observation was uneventful and the six week follow up duplex ultrasound confirmed absence of luminal flow in the aneurysm. DISCUSSION: The treatment threshold of visceral aneurysms and treatment modalities are reviewed.

A near infrared spectroscopy-based test of calf muscle function in patients with peripheral arterial disease.

Background The study aims to test a new, simple, and reliable apparatus and procedure for the diagnostics and treatment evaluation of peripheral arterial disease (PAD). The test apparatus involves near infrared spectroscopy (NIRS) of a main part of the lower leg muscles during isometric flexion and extension of the ankle joint performed with the foot strapped in a specially designed pedal ergometer. Design To evaluate the reproducibility of the new test compared with an existing testing method of treadmill walking. Methods Eleven patients participated in the study: nine patients with claudication and two age-matched patients without claudication. Each patient was tested with an isometric ergometer pedal test and a treadmill test applying NIRS measurements of the anterior tibial and the gastrocnemius muscles (GAS). Tests were repeated three times with randomly selected intervals between individual test runs. Intraclass correlation constant (ICC) was used to describe reproducibility. The ICC was calculated using the area under the NIRS oxygenated hemoglobin (Hbox) curve, the initial velocity of the Hbox recovery curve, force measurements, and walking time. Results The ICC of the GAS was between 0.92-0.95 (foot-pedal) and 0.70-0.98 (tread mill) and of the anterior tibial muscle was between 0.87-0.96 (foot-pedal) and 0.67-0.79 (tread mill). Conclusion In this study, we contribute a new apparatus and test protocol for peripheral arterial disease (PAD) applying NIRS technique and controlled physical activity to evaluate the degree of muscle oxygenation under specific functionally relevant conditions. Thus, we have developed a clinically applicable "easy-to-do" exercise test of patients with chronic PAD which show high reproducibility.

Hygroma following endovascular femoral aneurysm exclusion: A case report.

INTRODUCTION: Endovascular treatment of aneurysms in the superficial femoral artery (SFA) and popliteal segments is a suggested alternative to open surgical repair. Careful selection of patients for endovascular treatment of SFA aneurysms is mandatory. PRESENTATION OF CASE: A complication due to endovascular stent-graft treatment in an 80-year old male with a 6 cm aneurysm in the SFA is presented. Hygroma developed after a partially unintended extravascular placed stent-graft. Two consecutive explorations resulted in a femoro-popliteal Polytetrafluoro-ethylene (PTFE) by-pass graft as the final solution. DISCUSSION: Several explanations for the patient's complications are suggested. CONCLUSION: A primary femoral-femoral/popliteal by-pass might be the best solution in SFA aneurysms due to risk of stent complications.

Metabolism of perfused pig intercostal muscles evaluated by 31P-magnetic resonance spectroscopy.

This study presents a perfused preparation for evaluation of metabolism in pig intercostal muscle in vitro. Preserved vessels and nerves to an intercostal segment including two adjacent ribs allowed for tissue perfusion and electrical stimulation with measurement of contraction force, oxygen consumption and 31P-magnetic resonance spectroscopy (31P-MRS). When perfused at rest with Krebs-Ringer buffer, the preparation maintained physiological levels of phosphocreatine (PCr), inorganic phosphate (Pi), ATP and pH at a stable oxygen consumption of 0.51 +/- 0.01 micromol min(-1) g(-1) for more than 2 h. Tonic stimulation of the nerve caused anaerobic energy consumption as PCr and pH decreased, and both variables recovered after the contraction with half-time values of approximately 7 min. Force increased to 0.040 N g(-1) (range, 0.031-0.103 N g(-1)) and it gradually decreased by about 70% during the subsequent 5 min of stimulation. The calculated free ADP concentration increased from 7.4 +/- 2.1 nmol g(-1) at rest to 28 +/- 12 nmol g(-1) (mean +/- s.d.) by the end of the stimulation. Thus anaerobic ATP turnover was zero at rest, 6.1 +/- 2 micromol min(-1) g(-1) during the first minute of stimulation and 3.5 +/- 0.5 micromol min(-1) g(-1) during the two last minutes, corresponding to the drop in force. When the preparation was left unperfused, anaerobic ATP turnover averaged 0.40 +/- 0.15 micromol min(-1) g(-1) for the first 10 min. The preparation can also be applied to human intercostal muscles, as demonstrated in one preliminary experiment. The results demonstrate a stable and functional in vitro preparation of intact perfused intercostal muscles in the pig.