Abstract
Suboptimal iliofemoral artery access requiring alternative trans-catheter aortic valve replacement (TAVR) access is still encountered in 10–20% of subjects undergoing TAVR. Attempting suboptimal vascular access may result in excessive vessel injury, bleeding and even death. Reported is an innovative procedure to address suboptimal heavily calcified iliofemoral access by using Diamondback 360 peripheral orbital atherectomy (POA) to ablate heavy endoluminal vascular calcifications followed by balloon angioplasty. This approach enabled us to successfully deploy TAVR in extremely challenging iliofemoral anatomies that would otherwise be rendered prohibitive. The technical aspects of this procedure are delineated accompanied by a descriptive case of such procedure.
Highlights
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In the absence of alternative access, in a frail patient with heavily and circumferentially calcified and stenosed iliofemoral vessels, Diamondback 360 POA with adjunct balloon angioplasty should be considered to allow transfemoral TAVR.
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This procedure requires 6F sheath access (either antegrade or retrograde via radial, ulnar or brachial or contralateral access) and requires minimal use of contrast.
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The 2 mm Solid or Classic crowns are the most frequently used crowns, deployed at escalating rotational speeds. POA should be accompanied 7-8 mm balloon angioplasty.
1
Introduction
Iliofemoral stenosis especially when accompanied by circumferential endoluminal calcifications is a major barrier for using femoral access for TAVR. The current use of alternative access varies between 10 and 20%. Alternative accesses have their set of disadvantages and limitations and may not be suitable for certain patient subsets.
The required minimal access for the 3 predominant valves as well as the outer diameter of the corresponding non-expanded and expanded TAVR sheaths are charted in Table 1 . Heavy calcification and especially circumferential calcification can result in inability to advance the TAVR sheath, tear of the TAVR sheath, inability to advance the valve within the TAVR sheath, “nose cone” capsule malalignment with Evolut-R and Evolut R Pro, delivery system dysfunction and vascular injury, bleeding and even death.
| Device | Valve size (mm) | Sheath required | Minimal vessel diameter (mm) | Largest external sheath or expanded sheath diameter (mm) | Valve external capsule diameter |
|---|---|---|---|---|---|
| Edwards S3 | 20 | 14 F eSheath | 5.0 | No data | n/a |
| 23 | 14 F eSheath | 5.5 | 5. 9 ± 0.12 | n/a | |
| 26 | 14 F ± eSheath | 5.5 | 7.65 ± 0.34 | n/a | |
| 29 | 16 F eSheath | 6 | 7.65 ± 0.34 | n/a | |
| Evolut R | 23, 26, 29 | InLine Sheathless 14 F or 18 F sheath | 5 | 6.7 | 6 mm/18 F |
| 34 | InLine Sheathless 16 F or 20 F sheath | 6 | 7.5 | 6.7 mm/20 F | |
| Evolut R Pro | 23, 26, 29 | InLine Sheathless 16 F or 20 F sheath | 6 | 7.5 | 6.7 mm/20 F |
| Lotus | 23 | Lotus sheath small | 6 | 7.4 | n/a |
| 25, 27 | Lotus sheath large | 6.5 | 7.9 | n/a |
2
Iliofemoral POA
Diamondback 360 POA (CSI Minneapolis, MN, USA) was extensively evaluated in >4500 subjects (enrolled in clinical registries and studies) with peripheral vascular disease cohorts and was found to be a relatively safe and efficient tool to employ in heavily calcified vessels as adjunct to balloon angioplasty. Analysis of study and registry data suggests satisfactory outcomes for various arterial locations (Popliteal and infra-popliteal [ ], superficial [ ] and deep femoral [ ] and iliac [ ]). The device performs preferential ablation of highly calcific lesions [ ] with relative sparing of non-calcific sites. The ablation of the endoluminal calcifications was accountable in one study for 86% of luminal gains [ ]. In subjects with calcific lower extremity arterial disease orbital atherectomy reduces the likelihood of suboptimal angiographic outcome and procedural failure and even overall medical cost [ ]. POA also reduces the required inflation pressures for the treated vessels (average 5.2 ± 1.2 atm) and reduces the need for repeat revascularizations along with the frequency of major adverse events associated with interventions including dissection [ ], perforation, bailout stenting, embolization [ ] when compared to balloon angioplasty or even drug coated balloons.
A sub-analysis of the CONFIRM [ ] registries suggested that POA of iliac disease is at least as safe as femoral POA with fewer (2.9% vs. 11.2% p = 0.03) angiographic complication (perforations, flow-limiting dissections, slow flow, vessel closure, spasm, embolism, or thrombosis).
POA is performed using the dedicated 0.014″ stainless-steel silicone coated Viper wires (CSI) most contain a 3-cm radio-opaque spring tip of platinum/tungsten. The relevant crown sizes and POA systems with their range ex-vivo ablation diameters are presented in Table 2 . For iliofemoral POA predominantly the 2 mm Crowns should be employed. Sub-total occluded calcific lesions will be better served by the 2-mm classic crown than by the 2-mm solid crown in view of its more tapered proximal nose-cone. Both crowns require a 6 F sheath or guiding catheters with internal diameter ≥0.079″ (≥2.007 mm). Potential guiding catheters for 2 mm crowns are all 8 F coronary guiding catheters, 7.5 F Eaucath (internal diameter 0.081″) sheathless guide (Asahi Intecc Japan), 7 F (internal diameter 0.081″) Mach 1 guide (Boston scientific, Natick, MA, USA). Gradual increase in the rotational speed (the 3 standard rotational speeds are 60,000, 90,000 and 120,000 or 140,000 RPM) and to some extent the number and duration of the POA runs increases the diameter of the effective ablation. Dedicated lubricant (ViperSlide, CSI) or saline must be administered during POA via a dedicated pump.
| Diamondback 360 Crowns for iliofemoral procedures (catalogue code) | Sheath size (F)/internal diameter (Inches) | Shaft length (cm) | Nose b length (mm) | Maximal lumen diameter at 3 speeds a (mm) | Preferred wires GW 335 mm EL 475 mm |
|---|---|---|---|---|---|
| 2 mm classic (DBP-200CLASS145) | 6 F 0.079 | 145 | 20 | 2.44, 2.63, 2.95 | VPR-GW-14, VPRGWFT14 VPR-GW-17, VPR-GW-FT18 |
| 2 mm solid (DBP-200SOLID145) | 6 F 0.079 | 145 | 30 | 3.18, 4.35, 6.05 | VPR-GW-14, VPRGWFT14 VPR-GW-17, VPR-GW-FT18 |
| 1.75 mm solid (DBP-175SOLID180) | 5 F 0.070 | 180 | 30 | 2.73, 3.52, 4.62 | VPR-GW-EL14 VPR-GW-EL18 |
| 1.5 mm solid (DBP-150SOLID145) | 5 F 0.063 | 145 | 10 | 2.44, 2.98, 3.86 | VPR-GW-14, VPRGWFT14 VPR-GW-17, VPR-GW-FT18 |
| 1.5 mm solid (DBP-150SOLID200) | 5 F 0.063 | 200 | 10 | 2.44, 2.98, 3.86 | VPR-GW-EL14 VPR-GW-EL18 |
| 1.5 mm classic (DBP-150CLASS145) | 5 F 0.063 | 145 | 15 | 1.82, 2.08, 2.34 | VPR-GW-14, VPRGWFT14 VPR-GW-17, VPR-GW-FT18 |
a At three standard rotation speeds 60,000, 90,000 and 120,000 (solid) 140,000 (classic) RPMs for crowns without wire bias.
Wire bias, whether planned or unplanned, can further enhance the extent of directional ablating. Planned wire bias can be performed by ablation via an angled tip guiding catheter or an angled sheath which allows executing directional ablation within the vessel wall without crown escalation. Quantitative measurements and procedural guidance evaluating the effects of POA can be obtained using intra-vascular ultrasound. The full expansion of an 8-mm angioplasty balloon following POA will be a good indication that all frequently used TAVR sheaths and USA commercially available TAVR valves would be able be advance through the treated lesions.
The potential advantages of POA (accompanied by balloon or drug eluting balloon angioplasty) over direct balloon or cutting balloon angioplasty are: a) selective ablation of endoluminal calcium to minimize unfavorable interaction with TAVR sheath or delivery system; b) modifying vessel compliance and consequently reducing inflation pressures, barotrauma and vessel dissection or inability to advance the TAVR sheath or valve; c) predictable luminal gain to reduce restenosis when using adjunct balloon or drug eluting balloon-angioplasty or stenting; d) less suboptimal angiographic results minimizing the need for unplanned use of stents and covered stents (which can result in problematic interactions during TAVR) and e) optimal stent or covered stent delivery, deployment and expansion when unplanned stenting it is required.
2.1
The major downside of POA is the device cost
The cost of the PAO system (2 mm Classic Crown) is ~3195$, the cost of the Viper wire ~195$ and the cost of the optional ViperSlide is ~80$. Potential device related complications are distal embolization (<1%) acute vessel closure or perforation [ ] (1.6%) especially in small diameter vessels [ ].
2
Iliofemoral POA
Diamondback 360 POA (CSI Minneapolis, MN, USA) was extensively evaluated in >4500 subjects (enrolled in clinical registries and studies) with peripheral vascular disease cohorts and was found to be a relatively safe and efficient tool to employ in heavily calcified vessels as adjunct to balloon angioplasty. Analysis of study and registry data suggests satisfactory outcomes for various arterial locations (Popliteal and infra-popliteal [ ], superficial [ ] and deep femoral [ ] and iliac [ ]). The device performs preferential ablation of highly calcific lesions [ ] with relative sparing of non-calcific sites. The ablation of the endoluminal calcifications was accountable in one study for 86% of luminal gains [ ]. In subjects with calcific lower extremity arterial disease orbital atherectomy reduces the likelihood of suboptimal angiographic outcome and procedural failure and even overall medical cost [ ]. POA also reduces the required inflation pressures for the treated vessels (average 5.2 ± 1.2 atm) and reduces the need for repeat revascularizations along with the frequency of major adverse events associated with interventions including dissection [ ], perforation, bailout stenting, embolization [ ] when compared to balloon angioplasty or even drug coated balloons.
A sub-analysis of the CONFIRM [ ] registries suggested that POA of iliac disease is at least as safe as femoral POA with fewer (2.9% vs. 11.2% p = 0.03) angiographic complication (perforations, flow-limiting dissections, slow flow, vessel closure, spasm, embolism, or thrombosis).
POA is performed using the dedicated 0.014″ stainless-steel silicone coated Viper wires (CSI) most contain a 3-cm radio-opaque spring tip of platinum/tungsten. The relevant crown sizes and POA systems with their range ex-vivo ablation diameters are presented in Table 2 . For iliofemoral POA predominantly the 2 mm Crowns should be employed. Sub-total occluded calcific lesions will be better served by the 2-mm classic crown than by the 2-mm solid crown in view of its more tapered proximal nose-cone. Both crowns require a 6 F sheath or guiding catheters with internal diameter ≥0.079″ (≥2.007 mm). Potential guiding catheters for 2 mm crowns are all 8 F coronary guiding catheters, 7.5 F Eaucath (internal diameter 0.081″) sheathless guide (Asahi Intecc Japan), 7 F (internal diameter 0.081″) Mach 1 guide (Boston scientific, Natick, MA, USA). Gradual increase in the rotational speed (the 3 standard rotational speeds are 60,000, 90,000 and 120,000 or 140,000 RPM) and to some extent the number and duration of the POA runs increases the diameter of the effective ablation. Dedicated lubricant (ViperSlide, CSI) or saline must be administered during POA via a dedicated pump.
