Abstract
Reliance on angiographic detection of peripheral embolic events during endovascular treatment of peripheral arterial disease not only underestimates its true incidence but is the leading cause for underdeveloped embolic protection strategies during peripheral arterial interventions. Detection of distal embolic signals especially during percutaneous treatment of infra-inguinal chronic total occlusions (CTO) remains unknown. We report Doppler ultrasound detection of distal embolic signals, during phases of percutaneous intervention involving recanalization of a superficial femoral artery CTO.
1
Introduction
Chronic total occlusion (CTO) comprises a significant portion of infra-inguinal peripheral arterial lesions, is a marker of more extensive peripheral arterial disease (PAD) and occurs most commonly in the superficial femoral artery (SFA) distribution . Endovascular CTO recanalization has gained increasing acceptance over surgical bypass; however, the risk of peripheral embolization (PE) during percutaneous treatment of SFA CTO remains undefined. PE during endovascular revascularization of SFA CTO can potentially lead to worsening ischemia or even limb loss. Currently, angiographic detection of PE merely documents it in retrospect. Angiography underestimates the true incidence and has potentially contributed to the lack of awareness to this serious complication leading to underdevelopment of peripheral embolic protection strategies. There are few reports which have demonstrated detection of distal embolic signals (ES) with continuous transcutaneous Doppler ultrasound , however not during endovascular treatment of SFA CTO. As presence of an infra-inguinal CTO is associated with more extensive PAD and incremental risk of limb ischemia or loss from PE, knowledge of ES during SFA CTO interventions may allow operators to include strategies that mitigate this risk. In this report, we describe, for the first time, detection of ES with Doppler ultrasound during phases of an endovascular recanalization of SFA CTO: crossing, atherectomy/debulking, pre-dilation, stent implantation, and post-dilation.
2
Case presentation
A 55-year-old man with a history of coronary artery disease and severe PAD status post aorto-bi-femoral bypass was referred for percutaneous treatment of a left SFA CTO for lifestyle-limiting claudication (Fontaine class II). Ankle brachial indices of the right and left lower extremity were 0.70 and 0.58, respectively. Diagnostic angiography revealed occluded lower extremity bypass grafts, left SFA ostial occlusion with mid SFA reconstitution ( Fig. 1 A ), and diffuse disease two vessels below the knee runoff.
During the intervention, a 2-MHz transcranial Doppler ultrasound probe was secured in the ipsilateral popliteal fossa with synthetic adhesive tape to continuously record ES during each phase of the procedure. A 6-dB intensity threshold above peak background intensity was considered indicative of an ES ( Fig. 2 ). Through a 6F 45-cm arterial sheath placed through the contralateral common femoral artery, a Crossboss crossing catheter (BridgePoint Medical, Plymouth, MN, USA) was advanced and manually torqued and spun to traverse the CTO through to the distal reconstitution site true lumen ( Fig. 1 B). The proximal cap of the SFA was initially crossed with a treasure wire and a quick cross support catheter. Laser atherectomy was then performed with a 2.0 Turboelite laser (Spectranetics, Colorado Springs, CO, USA) ( Fig. 1 C). Post-laser debulking ( Fig. 1 D), the residual lesion was then pre-dilated with a 5×60 mm Proteus balloon (Angioslide, Herzliya, Israel) ( Fig. 1 E). Following balloon dilation, two overlapping nitinol self-expanding Smart stents (6×60 and 6×100 mm; Cordis, Miami, FL, USA) were deployed and subsequently post-dilated with a 6×150 mm Cryoplasty balloon (Boston Scientific, Natick, MA, USA) ( Fig. 1 F), with an excellent angiographic result ( Fig. 1 G and H) and preserved distal flow. Doppler ultrasound ES were recorded during each phase of the SFA recanalization, namely, crossing, atherectomy/debulking, pre-dilation, stent deployment, and stent post-dilation ( Table 1 ).
| Number of embolic signals at various phases of procedure | |
|---|---|
| Phases | ES |
| Baseline, pre-treatment | 0 |
| Transversal of CTO with Crossboss catheter | 31 |
| Laser atherectomy | 12 |
| Pre-dilation with Angioslide balloon | 7 |
| Distal stent placement | 18 |
| Proximal stent placement | 34 |
| Post-dilation | 17 |
| Post-recanalization | 4 |
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