The incidence of vascular access site related complications ranges between 0.8 % to 1.8 % of diagnostic cardiac catheterization and up to 9 % of percutaneous coronary interventions (PCI) [1]. The femoral vessels at the groin are used as the access site for the majority of percutaneous coronary, peripheral arterial and venous, and electrophysiologic interventions. With emergence of endovascular abdominal aortic aneurysm repair (EVAR), thoracic endovascular aneurysm repair (TEVAR), and transcatheter aortic valve replacement (TAVR), larger access sheaths (up to 18Fr-24Fr) are required, which further increases the potential for access site complications. The true incidence of access site complications arising from non-coronary interventions is unknown; hence it is likely that the total incidence of vascular access site complications is greatly underestimated. Vascular closure devices (VCDs), radial artery access, fluoroscopic guidance, and ultrasound guidance have all been used with a hope to minimize these complications. Despite these attempts, vascular access complications have not been eliminated. Cardiovascular specialists must promptly identify these complications and manage them appropriately.

A 40-year-old Caucasian male with prior history of hypertension, dyslipidemia, and coronary artery disease was admitted with severe right lower extremity swelling and tightness. An magnetic resonance venogram (MRV) confirmed acute deep venous thrombosis (DVT) of the right common femoral, common iliac and external iliac veins along with femoro-popliteal, tibial and peroneal vein DVT. Pharmacomechanical thrombectomy and thrombolysis (PMTT) was offered, given his young age and severe symptoms. An initial venogram was performed via right popliteal access. An EKOS (Ekos Corporation, Bothell, WA, USA) catheter was then inserted to achieve accelerated thrombolysis.The EKOS catheter is a mechanical thrombolysis catheter that uses acoustic microstreaming and ultrasonic agitation to alter thrombus structure and allow the thrombolytic therapy to be more effective. The catheter consists of a series of ultrasound transducer elements spaced approximately 1.0 cm apart along its leading tip to deliver ultrasound energy radially along with the coaxial infusion.A venous duplex was ordered 6 hours after the initiation of PMTT to assess the extent of thrombolysis. The images demonstrated an interesting finding of frequency interference artifact from the interaction of a linear ultrasound transducer (9-3 MHz) and the low frequencies emitted from the EKOS transducer elements (1.1 MHz, 0.45 W) at a pulse repletion frequency of 30 Hz and a duration of 2.5 ms.1,2 This interference artifact is well demonstrated on the spectral Doppler tracing obtained within the common femoral vein (CFV) (Panel A). In addition, the B-mode image of the CFV demonstrated diamond-shaped and spotlight-like artifacts arising from the bottom of the screen (Panel B). Frequency interference artifact is a type of susceptibility artifact that normally is caused by an external source such as a radio signal, television signal or a pulse oximeter. 3 In this case, the artifact originated from within the CFV owing to the ultrasound pulsations of the EKOS catheter.Panel A

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Venous duplex scanning can be divided into two different subcategories: (1) scanning to diagnose thrombus and (2) scanning to diagnose incompetence. Venous incompetence testing is used to assess the physiology of the superfi cial and deep venous systems, making it a much more complex and time-consuming test, primarily because sonographers need to take into consideration the great number of anatomical variations of the superfi cial venous system, venous fl ow patterns, as well as physiology. To perform these examinations effi ciently and to obtain consistent results, it is imperative to standardize protocols and to break down these examinations into manageable components.

In-stent restenosis is complex, difficult to treat and has led to a ‘leave less metal behind’ approach to femoropopliteal intervention. Postangioplasty dissection often requires scaffolding to maintain patency. The Tack Endovascular System provides minimal-metal dissection repair that preserves future treatment options. Tack implants are designed to minimise the inflammation and neointimal hyperplasia that lead to in-stent restenosis. An independent angiographic core laboratory evaluated the restenosis patterns in clinically driven target lesion revascularisation (CD-TLR) during the 12 months following the index procedure in the Tack Optimized Balloon Angioplasty (TOBA) II study and compared these results to those published for nitinol stent implantation. Of the 213 patients in TOBA II, 31 (14.6%) required a CD-TLR. Of these, 28 had angiograms that were evaluated by the core laboratory, and 45.2%, 16.1%, and 29% were graded as Tosaka class I, II and III, respectively. There were no significant differences (p>0.05) in lesion length, degree of calcification or dissection class between the three groups. Tack restenotic lesion classification and analysis show a prevalence of both class I and shorter lesions relative to in-stent restenosis, which may be beneficial to long-term patient outcomes.