Ultrasonic plaque character and outcome after lower limb angioplasty

Residual Vein Thrombosis Echogenicity Is Associated to the Risk of DVT Recurrence: A Cohort Study

Although deep vein thrombosis (DVT) recurrence is a common late complication of the disease, there are few predictive markers to risk-stratify patients long-term after the thrombotic event. The accuracy of residual vein thrombosis (RVT) in this context is controversial, possibly due to a lack of a standardized methodology. The objective of the study was to evaluate the accuracy of RVT echogenicity as a predictive marker of late DVT recurrence. To evaluate the accuracy of RVT echogenicity as a predictive marker of late DVT recurrence. This prospective study included patients with history of DVT in the past 33 months. Ultrasound examination was performed to detect the presence of RVT, and its echogenicity was determined by calculating the grayscale median (GSM) of the images. Blood samplings were taken for plasma D-dimer levels. Patients were followed-up for 28 months and the primary end point was DVT recurrence. Deep vein thrombosis recurrence was confirmed or excluded by ultrasound during the follow-up. Fifty-six patients were included, of which 10 presented DVT recurrence during the follow-up. D-dimer levels above 630 ng/mL conferred higher risk for recurrence with a negative predictive value of 94%. The absence of RVT was a protective marker for recurrence with a negative predictive value of 100%. Also, the presence of hypoechoic RVT, determined by GSM values below 24, positively predicted 75% of DVT recurrences. Our results suggest that the persistence of RVT and, particularly, the presence of hypoechoic thrombi (GSM < 24) are predictive markers of the risk of DVT recurrence. Residual vein thrombosis echogenicity, by GSM analysis, could represent a new strategy for the evaluation of recurrence risk in patients with DVT.

The Role of Hemodynamic Measurements in the Management of Venous and Ischemic Ulcers

There is a need for quantitative investigations in the vascular laboratory to manage lower extremity ulcers. The majority of leg ulcers are of venous (45%-60%) or arterial origin (10%-20%). Despite the increasing complexity of new devices used in vascular surgical practice, the anklebrachial pressure index (ABPI) remains the cornerstone for the differential diagnosis of ischemic ulcers. The toe-brachial pressure index and the pole test represent attractive alternative tests especially in patients with diabetes. Color flow Doppler imaging (CFDI) is advantageous over ABPI in cases in which wounds and ulcers prevent the use of a cuff by virtue of their size or location; additionally CFDI technology can detect nonflow limiting lesions, lesions to nonaxial arteries such as the deep femoral artery, or lesions limited to a single tibial artery. Continued improvements in the accuracy of CFDI have prompted some vascular surgeons to replace contrast arteriography in distal bypass procedures. Transcutaneous partial oxygen tension measurement (TcPO2) is another noninvasive method that is reliable to select the level of amputation and recommended to determine tissue viability in critically ischemic limbs and in the management of the diabetic foot. CFDI has revolutionized the diagnostic approach to venous disorders and it is considered the gold standard for the assessment of the venous system of the lower limb, causes minimal inconvenience to patients, and is easily repeatable, but it is considered highly operator dependent. Various plethysmography techniques are of limited application in ulcer investigations, because of their difficulty to calibrate signal, unless time measurements such as the postexercise refilling time are used.

Assessment of deep venous thrombosis by grayscale median analysis of ultrasound images

AIM

This study aimed to determine whether grayscale median (GSM) ultrasound (US) analysis could differentiate acute from subacute femoropopliteal deep venous thrombosis (DVT) classified based on (a) the time of symptoms onset and (b) sonographers' evaluation of US images.

METHODS

Patients who had US because of suspected DVT were included. Patients with history of previous DVT, with normal US results or US with findings of isolated calf thrombosis were excluded. A total of 128 venous segments of 63 patients were analyzed. Thrombosed veins and adjacent arteries images were recorded. Thrombi GSM were calculated. Grayscale median was compared with (a) the time of symptoms onset and (b) US image thrombi classification as acute or subacute done by 2 sonographers blinded to patient information. Statistical analysis included GSM Pearson intraobserver variability and t test comparisons of GSM means for (a) short versus long onset periods and (b) acute versus subacute US class, χ comparison between onset history and US class, creation of GSM accuracy, predictive values, and sensitivity curves for acute versus subacute DVT.

RESULTS

Intraobserver variability correlation varied between 0.92 and 0.95. Thrombus mean GSM was 23 ± 12 versus 31 ± 16 if symptoms onset was shorter or longer than 2 weeks (P = 0.004). Mean GSM was 20 ± 11 versus 35 ± 14 for acute versus subacute thrombi (P < 0.001). Acute thrombi correlated with onset shorter than 2 weeks (P < 0.001). Grayscale median less than 13, equal to 22, or 33 or less had 85% positive predictive value (17/20), 77% accuracy (98/128), and 90% sensitivity (53/59) to differentiate acute from subacute thrombi.

CONCLUSIONS

Grayscale median of US images documenting femoropopliteal DVT correlated with (a) the time between symptoms onset and US examination and (b) the sonographers' interpretation of acute versus subacute thrombosis.

Predictive factors of femoropopliteal patency after suboptimal duplex-guided balloon angioplasty and stenting: is recoil a bad sign?

Currently, the value of stenting during femoropopliteal balloon angioplasty (FPBA) remains unclear. Herein we evaluate the patency rates of successful duplex-guided balloon angioplasty (DAGBA) alone versus suboptimal DAGBA followed by stenting and the prestenting dissection versus recoil as potential indicators of stent success or failure. Over a period of 27 months, we performed 291 duplex-guided FPBAs (194 stenoses; 97 occlusions) on 244 limbs in 220 patients. Disabling claudication was the indication in 67%. Critical limb ischemia was the indication in the remaining 33%. Self-expanding nitinol stents were used when plaque dissection and/ or recoil caused diameter reduction > or = 40%. Serial follow-up duplex scans were obtained. Severe restenosis (> 70%) was measured by B-mode imaging and a peak systolic velocity ratio > 3. Follow-up ranged from 1 to 41 months (mean 10 +/- 8.3 months). The overall mean interval for restenosis and occlusion was 6.5 +/- 4.2 months and 5.6 +/- 6.1 months, respectively. Stents did affect overall patency results compared with not using stents. Reasons for stenting were plaque recoil, dissection, or both in 98 (53%), 44 (24%), and 42 (23%) cases, respectively. Six-month patency was 59%, 94%, and 69%, respectively. The difference between plaque recoil and dissection was significant (p<.04). The use of stents during FPBA may be associated with balloon angioplasty site failure in the femoropopliteal segment. To our knowledge, this is the first report ever to document plaque recoil as a predictor of balloon angioplasty site failure notwithstanding stent placement.

Color Doppler US findings in the diagnosis of arterial occlusive disease of the lower limb

Peripheral arterial occlusive disease (PAOD) of the lower limb is a widely spread disease at the present time. After clinical examination, which includes a comprehensive history of the patient, different imaging modalities are competitive in the exact assessment of PAOD. Besides digital subtraction angiography and MR -angiography, color Doppler US is an established imaging modality in the diagnosis of PAOD. This article illustrates the typical color Doppler US findings in PAOD of the lower limb. Duplex images of normal and pathological findings are presented, and the limitations of the method are pointed out. Color Doppler US examination strategies in patients suffering of PAOD are outlined.

Possible impact of iridium-192 source centering on restenosis rate after femoro-popliteal angioplasty and endovascular brachytherapy in Vienna-2 study

PURPOSE

Endovascular brachytherapy (EVBT) has been proven to significantly reduce restenosis after percutaneous transluminal angioplasty (PTA). The object of this analysis was to assess the possible correlation between iridium-192 source non-centering and angiographic-determined restenosis.

MATERIALS AND METHODS

A total of 113 patients with long-segment lesions of the superficial femoro-popliteal artery (SFA) were randomized to receive either PTA alone or PTA followed by EVBT in the Vienna-2 study. This analysis was performed on a subgroup of 34 out of 57 patients, who received PTA+EVBT. Angiographic restenosis was defined as lumen reduction of more than 50%. Angiograms taken immediately after PTA (34 patients) and at follow-up (25 patients) were analyzed. The distance between the vessel wall and the actual position of the source at the time of EVBT was measured (in mm) and correlated with the follow-up vessel lumen diameter. Measurements were performed at points at a distance of 10 mm from each other. The dose was determined at the luminal surface and at the reference depth of 2 mm into the vessel wall for different distances from the source.

RESULTS

Among the 622 measured points, 62 (10.0%) were within restenotic areas; 560 (90.0%) were in arterial segments without proven angiographic restenosis. As far as source centering is concerned, 7.9% of restenotic points were observed when the maximum distance to the arterial wall was <3 mm and 9.6% for 4 mm, respectively. The percentage of restenotic points increased up to 15.9% when the maximum distance to the arterial wall was 5 mm and reached 22.2% when it was >5 mm.

CONCLUSIONS

The proportion of restenotic points significantly increased with source non-centering. This observation was interpreted as being related to a decrease in dose at the target. When the maximum distance between the source and the vessel surface was >5 mm, the dose at the reference depth (2 mm into the vessel wall) decreased to values lower than 5 Gy.

Real-time spatial compound imaging: application to breast, vascular, and musculoskeletal ultrasound

Real-time spatial compound imaging (SonoCT) is an ultrasound technique that uses electronic beam steering of a transducer array to rapidly acquire several (three to nine) overlapping scans of an object from different view angles. These single-angle scans are averaged to form a multiangle compound image that is updated in real time with each subsequent scan. Compound imaging shows improved image quality compared with conventional ultrasound, primarily because of reduction of speckle, clutter, and other acoustic artifacts. Early clinical experience suggests that real-time spatial compound imaging can provide improved contrast resolution and tissue differentiation that is beneficial for imaging the breast, peripheral blood vessels, and musculoskeletal injuries. Future development of real-time spatial compound imaging will help address the bulk of general imaging applications by extending this technology to curved array transducers, tissue harmonics, panoramic imaging, and three-dimensional sonography.

Mid-term follow-up after percutaneous hydrodynamic thrombectomy in lower limb ischemia: initial experience with two-dimensional MR imaging and three-dimensional MR angiography

PURPOSE

To assess noninvasively mid-term patency, reocclusion, and mid-term changes of the arterial wall after percutaneous hydrodynamic thrombectomy in patients with acute lower limb ischemia using magnetic resonance (MR) imaging/MR angiography (MRA).

MATERIALS AND METHODS

Arterial wall and luminal changes were evaluated in 16 patients (10 men, six women; mean age, 70 years), with a minimum follow-up of 12 months after percutaneous thrombectomy with a hydrodynamic catheter for acute lower limb ischemia (embolic, n = 5; thrombotic, n = 11). Adjunctive PTA was performed in 44%. The mean follow-up was 23 months +/- 7.6 (range, 12-33 months). MR imaging and MRA were performed on a 1.0 T system using an extremity coil and two-dimensional (2D) time-of-flight, turbo spin echo, 2D gradient echo, and contrast enhanced three-dimensional (3D) gradient echo sequences.

RESULTS

In one patient, a complete reocclusion was noted and, in two patients, a hemodynamically insignificant restenosis (< or = 50%) was identified with MR imaging. This was in accordance with color flow duplex sonography, physical examination, ankle/brachial index measurements, and the treadmill test. The MR morphometry documented an increase of the entire vessel area from 48.9 mm2 +/- 3.3 (control segments) to 55.5 mm2 +/- 2.8 at the treated segments (+13.3%; P < .05). The vessel wall area increased from 31.7 mm2 +/- 1.8 to 39.4 mm2 +/- 2.3 (+24.4%; P < .05). The mean area stenosis grade was 12%.

CONCLUSION

MR imaging with use of morphometric analysis is a possible tool to noninvasively determine the mid-term patency and restenosis/reocclusion and remodeling process after percutaneous thrombectomy and other interventional procedures.