INVESTIGATIONS IN VASCULAR DISEASES
Chairpersons: P. L. ANTIGNANI (Italy), K. JAEGER (Switzerland)
Treatment of postcatheterization femoral false aneurysms: usefulness of color Doppler
The incidence of iatrogenic femoral false aneurysms has risen dramatically in recent years, and is estimated at 0.5% for diagnostic and 9% for therapeutic procedures. This increased incidence related to the increased number of arterial punctures for diagnostic and therapeutic purposes and their major complexity and duration. Risk factors for development of iatrogenic false aneurysms include operator experience, age greater than 60 years, female gender, catheter size greater than 8F, atheromatic plaque presence, and concurrent anticoagulation. Prevention of false aneurysms is based upon an atraumatic arterial puncture, good compression therapy after the procedure, and use of precutaneous arterial closure devices. Contrary to the arterial lesions following severe injuries, the natural evolution of false aneurysms is quite benign, with spontaneous occlusion in the majority of cases. Therefore a mandatory surgical approach is no longer advocated, and alternative therapeutic options have been proposed. These include sonographic surveillance, compression ultrasonography, precutaneous thrombin, or coil embolization. Surgery is clearly indicated in the presence of local nervous or venous compression, associated homolateral lower limb ischemia, large size of aneurysm (>3 cm) and unsuccessful noninvasive treatment. Echographic surveillance has been shown to be safe in hospitalized or ambulatory patients. However, fear of aneurysm rupture and cost of repeated ultrasonographic exams preclude wide utilization. Compression echography is safe, and effectiveness varies between 70% and 100% according to studies. Thrombin injection seems particularly effective, is painless, and has a low rate of complications in expert hands. Severe anaphylactic reactions and severe coagulopathy in reexposed patients have been described, and represent a clear contraindication to thrombin injection. Coil embolization of false aneurysms is as effective as a thrombin injection, and has been reported in a limited number of patients. There is no formal consensus about treatment of the vast majority of nonsurgical false aneurysms. If compression therapy fails, precutaneous injection of thrombin or coil embolization are effective, and associated with a low complication rate. However, these techniques are less widely available, and necessitate an experienced operator.
Chairpersons: H. VAN DAMME (Belgium), D. UBBINK (The Netherlands)
This interesting workshop started with the presentation by M. Koelemay from Amsterdam, on how to study lower leg and foot arteries. He recommended the use of a linear transducer at a frequency of 5 MHz for the proximal track from the knee arch to the calf and a high-frequency transducer (7.5-10 MHz) for the distal part, due to the superficial location of vessels. In cases of superficial, severely calcified vessels, he suggested the use of lower frequencies. A venous preset was used considering the expected low flow in the lower leg arteries and the “Power-Doppler” function; also, the zoom option could facilitate visualization of very-low-flow and small vessels. He stressed the importance of ensuring that the leg is relaxed and not overstretched during the exam. He recommended the use of a good seat with mobile back, and arm and elbow rests in order to protect one’s back. Moreover, he presented a critical appraisal of the literature concerning crural duplex scanning (CDS). Some 29 studies between 1989 and March 2004 were identified, with an overall moderate methodological quality. Evidence from this literature suggests that CDS can safely be used as the sole pre-treatment imaging modality in patients with severe limb ischemia. Afterwards, Professor Albäck from Helsinki presented his experience on intraoperative scanning of infrainguinal autologous vein grafts. The detection and possible correction of these abnormalities early during the primary procedure would be of great importance. The exam should include vessel imaging, velocity spectra analysis, grading of stenotic lesions, and graft hemodynamics. He recommended the study of the whole length of the reconstruction, giving special attention to common sites of defects. Next, he defined the findings and actions recommended: when there are moderate defects (PSV 125-180cm/s or a velocity ratio between 2 and 3) the exam should be repeated under the effects of papaverine, and then repair performed if a severe hemodynamic defect is confirmed. When there is a detection of severe stenosis (PSV>180 cm/s, velocity ratio>3 and spectral broadening) it should always be repaired if possible. Another problem is when no stenosis is detected but there is a low graft flow with PSV< 45 cm/s or EDV< 8 cm/s these could be sings of graft failure, an angiogram should then be performed. Professor Schellong from Dresden presented his protocol for detecting DVT, based on a complete compression ultrasound from the femoral to the crural veins, and the hands,-on session started in which everybody could see the application of duplex scan on studying crural vessels.
Real-time ultrasound evaluation in PTA stenting
A. AMATO (Italy)
Precutanous transluminal angioplasty (PTA) has been used for several years to treat arterial stenosis in short obstructions. The vessels most frequently treated are the iliofemoral arteries, renal arteries, and subclavian arteries. The assessment for endovascular treatment should be not only morphological but clinical and functional, since PTA is not a technique without risks. In the last few years it has become possible, and in some cases recommended, to place endoluminal stents during the angioplasty to favor the maintenance of the dilatation. The PTA-stenting technique has been extended to other vessels such as carotid arteries. The follow-up is based on the color Doppler ultrasonography as the most suitable noninvasive method for early and late evaluation of the stent. It is possible to investigate stent position, relationship with the endoluminal surface, and eventually residual plaque. Besides, it can detect the flow quality, early complications such as thrombosis, or late complications such as restenosis. Compared with angiography the sensitivity and specificity was about 96% to 97%.
Utility of D-dimer in diagnosis of deep vein thrombosis in
hospitalized patients at high risk of venous thromboembolism
F. VERLATO, A. BERTAGNIN, G. CAMPORESE, M. NARDI, G. M. ANDREOZZI (Italy)
The authors of this work aimed to evaluate the utility of D-dimer as a screening tool in populations at high risk of DVT, optimizing the use of noninvasive imaging with ultrasound. They studied a population of patients who had been operated on for neurosurgical pathology. They studied, using ultrasound, 103 patients with high levels of D-dimer, but only 31 patients had DVT. There is not a clear level which indicates patients at greater risk of a DVT. One way of increasing the positive and negative predictive value is to use a two-step screening process involving an initial D-dimer estimation to improve the utility of D-dimer in DVT diagnosis.
The appropriate use of the duplex scan in carotid artery
T. MEHTA, I. CHETTER, A. VENKATASUBRAMA, K. MYLANKAL, B. RAY, P. McCOLLUM (UK)
The authors examinded carotid ultrasound studies of patients with specific and nonspecific symptoms, from several medical specialties, over 25 months. The higher incidence detection of a significant internal carotid artery (ICA) stenosis (higher than 70%) was in patients from the vascular surgery ward (25.4% of scans) and the lowest was from the neurology service (5.9% scans). The authors recommenderedefined protocols for carotid duplex requests to increase efficiency and improve the pick-up rate of significant ICA lesions. It is necessary to develop good protocols, but these protocols must include both symptomatic and asymptomatic patients.
Duplex sonography in obstructive aortoiliac disease:
the diagnostic value of flow reversal in the inferior
M. HAUMER, R. A. BUCEK, M. SCHILLINGER, A. HAUMER, M. REITER, J. LAMMER, E. MINAR
The authors obtained spectral Doppler curves by duplex sonography in the inferior epigastric arteries of 78 patients with aortoiliac arterial pathology. They compared the results with those of conventional angiography. They describe several spectral Doppler curves to define the severity of aortoiliac pathology.
This test could be another tool to study arterial pathology with noninvasive methods, but is probably more useful for studying the spectral curves measured in the common femoral artery. Moreover, it is necessary to consider the influence of superficial femoral artery pathology in the curves registered in the common femoral artery or in the epigastric artery.
Noninvasive foot blood volume measurement
in the assessment of limb ischemia
T. KANETAKA, T. KOMIYAMA, A. ONOZUKA, T. MIYATA, H. SHIGEMATSU (Japan)
The authors have developed a new air chamber to measure blood volume in the foot by an air plethysmography technique.
The results of this work demonstrate that the fee of patients with critical ischemia contain more blood than those of patients with claudication or healthy people, and this might be due to the vasodilation compensating for the decrease of inflow.
The method could be problematic in patients with ischemic lesions, but could be a useful tool in diabetic patients, in whom arterial calcification does not permit the use of cuff pressure.