Development of a Duplex Ultrasound Protocol for Baseline and Follow-Up Imaging of a Branched Aortic Endoprosthesis

Branched endoprostheses for endovascular repair of pararenal and thoracoabdominal aortic aneurysms are undergoing evaluation in prospective clinical trials. Duplex ultrasound has been a cornerstone of surveillance for vascular reconstructions. This paper describes the development and deployment of a standardized duplex imaging protocol to evaluate individuals who have undergone endovascular repair of their thoracoabdominal aortic aneurysm. Ultrasound imaging is performed after an 8 to 12 hour fast to minimize the presence of bowel gas and allow for optimal imaging of abdominal vascular structures. Doppler measurements of peak systolic and end diastolic velocity are made at specific arterial segments in the aorta and the celiac, superior mesenteric, and renal arteries. Resistive indices are also recorded in the segmental and arcuate arteries of both kidneys. Pulsed-wave Doppler is used to record spectral Doppler data and color Doppler is used to image all arterial segments and ensure proper placement of the Doppler sample volume and ensure correct angle of interrogation. Implementation of a standardized duplex ultrasound imaging protocol can be used to image and follow individuals who have received the Thoracoabdominal Branch Endoprosthesis (TAMBE) device and branched endovascular aneurysm repair (BEVAR). Ultrasound may provide complementary findings and may add information to the computed tomography angiography imaging for following these individuals.

Direct oral anticoagulants decrease treatment failure for acute lower extremity deep venous thrombosis

Objective Optimal medical therapy for acute lower extremity deep venous thrombosis (DVT) remains an enigma. While clinical trials demonstrate non-inferiority with an oral anti-Xa inhibitor, or direct oral anticoagulant (DOAC), versus combined low–molecular weight heparin (LMWH) and oral vitamin K antagonist (VKA), the most effective regimen remains to be determined. Methods This study is a single-center retrospective cohort study from October 2014 to December 2015 of patients with a diagnosis of acute DVT and subsequent serial lower extremity venous duplex. Demographics, medical history, medications, serial ultrasound findings, as well as the primary anticoagulant used for treatment were collected and analyzed by two independent data extractors. Treatment failure was defined as any new DVT or progression of an existing DVT within 3 months of diagnosis of the index clot. Risk factors for treatment failure were assessed using standard odds ratios and Fischer’s exact test. Results Among 496 patients with an acute lower extremity DVT, 54% ( n = 266) were men, mean age was 61 years, 35% ( n = 174) involved the popliteal or more proximal segments, and 442 had documentation of the primary treatment for DVT: 20% ( n = 90) received nothing; 20% ( n = 92) received an oral VKA; 34% ( n = 149) received a DOAC; 20% ( n = 90) received LMWH; and 5% ( n = 21) received another class of anticoagulant. Within 3 months, 21% ( n=89 out of 427) had treatment failure defined as any new DVT or progression of prior DVT. Patients treated with a DOAC were less likely to experience treatment failure when compared with any other treatment (odds ratio 0.43; 95% confidence intervals [0.23, 0.79]; p = 0.0069) and when compared with traditional oral VKA (OR 0.44; 95% CI [0.21, 0.92]; p = 0.029). None of prior history of DVT, pulmonary embolism, thrombophilia, renal insufficiency, hepatic insufficiency, cancer, or antiplatelet therapy correlated with treatment failure. Treatment outcome did not correlate with being on any anticoagulation versus none ( p = 0.74), nor did it correlate with the duration of treatment (<3 months versus ≥3 months) ( p = 0.42). Proximal and distal DVTs showed no difference in treatment failure (19% versus 22%, respectively; p = 0.43). Conclusion In summary, the use of a DOAC for acute lower extremity DVT yielded better overall outcomes and fewer treatment failures at 3 months as compared to traditional oral VKA therapy based on serial duplex imaging.

A Review of Current Noninvasive Imaging Surveillance Practices for Deep Venous Arterialization Procedures

Venous arterialization is an increasingly common procedure performed in patients with critical limb-threatening ischemia (CLTI) where there are no open or percutaneous revascularization options. This study aims to review the imaging follow-up for venous arterialization described in the literature. A systematic review was performed on venous arterialization studies for CLTI using the PRISMA methodology. A literature search was performed on 5 databases from inception. We included all original studies, case reports, and reviews regarding venous arterialization for all pathologies. We excluded free standing abstracts, animal studies, other than lower extremity, and foreign language studies. Our search strategy yielded 23 studies that met inclusion criteria, with 16 studies reporting a specific value from at least one surveillance imaging methodology. Most studies used Duplex imaging (16 studies) and TCPo2 (9 studies). Only 9 studies provided any detail regarding the Duplex findings. One study used focal peak systolic velocity (PSV) gradient (PSV at the lesion in the graft divided by PSV in a proximal segment of the graft) above 2.5 as an indicator for flow-inhibiting venous valves or stenosis in the graft. Another study reported a turbulent flow pattern in the graft, elevating peak velocities to 100 to 200 cm/s throughout the bypass. Four studies reported flow volume measurement through the bypass or in pedal vein ranging from 40 to 437 mL/min. Seven studies reported a mean increase of 18.7 mmHg in TCPo2. Eighty-two percent of patients saw an improvement of TCPo2 in 2 studies. To date, no criteria have been identified that are predictive of the success or failure of deep vein arterialization. Venous arterialization is an increasingly common procedure in the “no-option” diabetic patient. Duplex imaging with TCPo2 offers the most appropriate means of surveillance; however, the literature is sparse with no guidance on normal or critical values.

The Feasibility of a Novel Index From a Wireless Doppler Ultrasound Patch to Detect Decreasing Cardiac Output in Healthy Volunteers

ABSTRACT Introduction Early hemorrhage is often missed by traditional vital signs because of physiological reserve, especially in the young and healthy. We have developed a novel, wearable, wireless Doppler ultrasound patch that tracks real-time blood velocity in the common carotid artery. Materials and Methods We studied eight healthy volunteers who decreased their cardiac output using a standardized Valsalva maneuver. In all eight, we simultaneously monitored the velocity time integral (VTI) of the common carotid artery (using the ultrasound patch) as well as the descending aorta (using a traditional pulsed wave duplex imaging system); the descending aortic VTI was used as a surrogate for left ventricular stroke volume (SV). Additionally, in a subset of four, we simultaneously measured SV using a noninvasive pulse contour analysis device. Results From baseline to peak effect of Valsalva, there was a statistically significant fall in descending aortic and common carotid VTI of 37% (P = 0.0005) and 23% (P &lt; 0.0001), respectively. Both values returned to baseline on recovery. Additionally, a novel index from the carotid ultrasound patch (i.e., the heart rate divided by the carotid artery VTI) detected a 10% fall in aortic VTI with high sensitivity and specificity (100% and 100%, respectively); this novel index also accurately detected a 10% decrease in SV as measured by the noninvasive SV monitor. The mean arterial pressure, measured by the noninvasive pulse contour device, did not correctly detect the fall in SV. Conclusion In summary, a novel index from a wireless Doppler ultrasound patch may be more sensitive and specific for detecting decreased cardiac output than standard vital signs in healthy volunteers.

Comparative Study between Conventional Surgery and Radiofrequency Ablation in Treatment of Varicose Vein

Background Varicose veins are a very common problem all over the world. Surgery has been the gold standard treatment for many years, however now other less invasive options are available and sometimes more efficient. Aim of the Work to evaluate the RFA technique in treatment of GSV varicosities and to compare the results, clinical outcome, complications and recurrence rate after RFA and CS of GSV. Patients and Methods This observational retrospective study included 41 patients with varicose vein recruited from general surgery department and vascular surgery unit at Ain Shams Hospitals and in Nasser Institute for Research and Treatment. Results Operative time was significantly less in CS compared to RFA. One , six and twelve months post intervention follow up using clinical examination and duplex imaging were used to asses outcome and detect complications and recurrence rate. No major complications were detected after both techniques; however minor post operative complications like paresthesia and ecchymosis were significantly less after RFA. Post operative pain, duration of analgesia use and time needed to return to normal activity were also significantly less in RFA group than CS group. Recanalization of GSV was not detected after radiofrequency maneuver nor CS. This study proved that radiofrequency ablation technique is a safe and efficient in treating varicose veins however long-term results and cost effectiveness need further evaluation. Conclusion Conventional surgery has been used for a long time for treatment of varicose veins with variable degrees of minor to major complications. Duplex guided radiofrequency ablation is an efficient and a safe modality in the treatment of great saphenous vein varicosities. Of most importance is an adequate Duplex scan to identify accessory channels and double superficial systems.

Dorsalis pedis artery aneurysm

Aneurysm of the pedal arteries is uncommon. Dorsalis pedis aneurysms are a clinically rare phenomenon. We present a case of traumatic fusiform aneurysm of the dorsalis pedis artery in an otherwise well 53-year-old Caucasian man. Initial history was suggestive of micro-embolic disease to the medial toes of the left foot and on examination pulses were palpable throughout the lower limbs with a strong, palpable dorasalis pedis pulse. Ankle brachial pressure indexes were normal but reduced toe pressures to the left toes. Colour flow duplex imaging revealed aneurysmal dilation, involving all layers of artery wall, with irregular intraluminal thrombus across a 16-mm segment. Subsequent CTA run-off revealed all vessels were patent in the left lower limb. Due to concerns over further embolisation, our patient underwent successful ligation of the his dorsalis pedis. He had an uneventful post-operative recovery.

A case of dissection in an ACUSEAL-modified HeRO graft

Background: The use of the HeRO system with the early-access ACUSEAL graft avoids the need for a tunnelled dialysis catheter as a bridge for vascular access. Established complications of this system include thrombosis, graft infection, haematoma, and pseudoaneurysm formation. Case Description: A 72-year-old patient found to have a dissection flap at the venous cannulation point (ACUSEAL component) of a right arm HeRO graft. The ACUSEAL was replaced in theatre and subsequent duplex imaging confirmed satisfactory graft function. Conclusion: This case demonstrates a serious yet previously undescribed complication of cannulation of an ACUSEAL graft. The trilaminar construction of the graft may increase the likelihood of disruption of the luminal layer during repeated needling and predispose it to dissection. Given the consequences of graft failure in such patients, urgent intervention is warranted when graft dissection is suspected.