Abstract
Availability of dedicated equipment and familiarity with its use are critical for successfully and safely performing chronic total occlusion (CTO) percutaneous coronary interventions (PCIs). CTO PCI equipment can be grouped into 12 categories: (1) sheaths, (2) guide catheters and guide catheter extensions, (3) microcatheters and support catheters, (4) guidewires, (5) dissection/reentry equipment, (6) snares, (7) equipment for balloon-uncrossable and balloon-undilatable lesions, (8) intravascular imaging, (9) equipment for managing complications, (10) equipment for minimizing operator radiation exposure, (11) balloons/stents, and (12) hemodynamic support devices. CTO crossing should always be performed by advancing a guidewire through a microcatheter (preferred) or over-the-wire balloon, with careful selection of guidewires based on the lesion characteristics. Specialized equipment can facilitate dissection/reentry, and snares may be needed for retrograde guidewire externalization. Guide catheter extensions can increase support and also facilitate retrograde CTO PCI. Small balloons, various microcatheters, laser, atherectomy, and scoring balloons are often needed for balloon-uncrossable and balloon-undilatable lesions. Intravascular ultrasonography and/or optical coherence tomography can assist with CTO crossing and stenting optimization, whereas covered stents and coils with appropriate delivery microcatheters are necessary for treating perforations, which is the most common complication of CTO PCI. Radiation scatter shields can minimize operator radiation exposure. Long, noncompliant balloons are often needed for lesion preparation after crossing and second-generation drug-eluting stents are used in CTO PCI to minimize the risk for restenosis. Hemodynamic support devices should be considered prophylactically in selected high-risk cases or used if a patient develops hemodynamic compromise during the procedure.
Keywords
Balloon, Coils, Complications, Covered stents, Drug-eluting stents, Equipment, Guide catheter extensions, Guide catheters, Guidewire, Intravascular ultrasonography, Laser, Microcatheter, Optical coherence tomography, Radiation, Rotational atherectomy, Sheaths, Snares
2.1
Introduction
One of the most frequently asked questions about chronic total occlusion (CTO) percutaneous coronary intervention (PCI), especially from programs early in the learning curve, is, “what equipment do I really need?”
Although many operators would like to have everything available, the reality is that equipment cost and space limitations require prioritization. Here are some criteria to use when deciding the must-haves for CTO PCI:
- 1.
At least one item that fulfills each of the requisite steps in CTO PCI (e.g., septal crossing, wire externalization, snaring, etc.) should be available.
- 2.
The operator should be familiar with the equipment, understand its strengths and limitations, and be willing to actually use it when required (otherwise it will expire on the shelf). In some cases, such as covered stents and coils, equipment expiration is to some extent expected given the low frequency of complications requiring their use ( Chapter 12 ).
Table 2.1 shows a must-have and a good-to-have checklist for CTO PCI, classifying equipment into 12 categories.
| Category No. | Equipment | Must Have | Good to Have |
|---|---|---|---|
| 1. | Sheaths | 6–8 French standard sheaths |
|
| 2. | Guides—guide catheter extensions |
|
|
| 3. | Microcatheters/support catheters |
|
|
| 4. | Guidewires a |
|
|
| 5. | Dissection/reentry equipment |
| |
| 6. | Snares | Ensnare or Atrieve 18–30 mm or 27–45 mm | Amplatz Gooseneck snares |
| 7. | Balloon uncrossable/ undilatable lesion equipment |
| Angiosculpt |
| 8. | Intravascular imaging | IVUS (any) |
|
| 9. | Complication management |
|
|
| 10. | Radiation protection |
| |
| 11. | Balloons and Stents |
|
|
| 12. | Hemodynamic support |
| ECMO |
a For radial operators, 300-cm wires may be required because the trapping technique ( Section 3.7 ) cannot be used in a 6 Fr guide catheter for trapping over-the-wire balloons, the CrossBoss catheter, and the Stingray LP balloon. In such cases, using a 6 Fr Trapliner can be useful. Alternatively, guidewire extensions (for the Asahi and Abbott guidewires) are needed. However, trapping can be performed for the Finecross, SuperCross, TwinPass, Turnpike (including Turnpike LP, Spiral, and Gold), Corsair, and the Tornus 2.1 microcatheter through a 6 Fr guide catheter with 0.071 inch internal diameter (such as Medtronic Launcher).
2.2
Sheaths
Many high-volume hybrid CTO operators routinely use bilateral femoral 45 cm long sheaths, which provide better guide catheter support and torquability compared with shorter sheaths. Long sheaths straighten iliac vessel tortuosity, facilitating guide catheter and wire manipulation and reducing the risk for guide catheter kinking. The 45 cm length usually allows the tip of the sheath to reach the level of the diaphragm ( Fig. 2.1 ). Although there is increased risk of thrombus formation within longer sheaths, this is rarely an issue, especially for retrograde CTO PCI, given the high ACTs (>350 s) achieved for this procedure.
If radial access is obtained, 6 Fr is the most commonly used sheath, although 7 or 8 Fr can often be used in larger radial arteries. The 7 Fr Slender sheath (Terumo) has 2.79 mm outer diameter, which is not much larger than the outer diameter of a 6 Fr standard sheath (2.62 mm), and allows use of 7 Fr guide catheters. Although radial access and smaller sheath size can reduce the risk for vascular access complications, disadvantages of 6 Fr guides for CTO PCI include:
- 1.
Weaker support as compared with larger guide catheters.
- 2.
Inability to use the trapping technique ( Section 3.7 ) for various key CTO PCI equipment, such as over-the-wire balloons and the CrossBoss catheter.
- 3.
Inability to use simultaneously a balloon and a covered stent (block and deliver technique, Section 12.1.1.2.3 ) in case of perforation.
A sheathless guide system (Eaucath, Asahi Intecc) allows CTO PCI with 7.5 Fr guides through an arterial puncture equivalent to that created by a 5 Fr sheath. An alternative approach is using regular 8 Fr guides delivered with a sheathless approach or using a short 8 Fr sheath. It offers all the advantages of regular 8 Fr catheters and the safety of the transradial approach. The inner and outer diameters of an 8 Fr guide are similar to a 6 Fr sheath. The technique involves introducing a long 110 cm dilator that comes with a 6 Fr 90 cm long Cook Shuttle sheath into a regular 8 Fr guide. Once the guide is inserted in the radial artery, the 0.035″ guidewire is removed, Rotaglide or a radial “cocktail” (60 mg lidocaine and 5 mg verapamil) is injected through the dilator, the wire is reintroduced, and the guide is advanced to the ascending aorta. Alternatively the balloon-assisted tracking technique can be used for sheathless placement of an 8 Fr guide catheter.
2.3
Guide Catheters, Y-Connectors, Guide Catheter Extensions
2.3.1
Diameter, Length, and Shapes
Dual 8 Fr guides are most commonly used for CTO PCI in the United States, whereas 7 Fr guides are most commonly used in Europe. Compared with smaller caliber guide catheters, 8 Fr guides provide enhanced support and improve vessel visualization.
In the donor vessel, 6 Fr guides can usually provide adequate support for delivering retrograde gear and may reduce the risk of donor artery dissection. Therefore, many operators use 6 Fr catheters from either the femoral or radial approach for retrograde access. This combination of a 6 Fr radial guide for the retrograde side and an 8 Fr femoral guide for the antegrade side is becoming increasingly popular. To maintain consistency and minimize the chance of accidental injections made through the wrong guide catheter during a case, many operators employ a standard approach of placing the right coronary artery guide catheter in the right femoral artery and the left coronary artery guide catheter in the left femoral artery.
Using at least one 90 cm long guide is often helpful for the retrograde approach, as it shortens the distance that a retrograde wire needs to cover to be externalized. It can also facilitate intraprocedural strategy change to a retrograde approach and allow the retrograde microcatheter to reach the antegrade guide for subsequent wire externalization, although 100 cm guides can also be used in most cases if the RG3 or R350 guidewires are available. Shorter (80 cm long) guides may not reach the coronary ostia in some patients and are not commonly used. The must-have guides are those with supportive shapes, such as the XB and EBU for the left coronary artery and AL for the right coronary artery.
Occasionally a vessel may not be able to be engaged despite using various guide catheters, requiring primary retrograde crossing (see Online Case 18 ).
2.3.2
Shortening the Guide Catheter
With availability of long externalization guidewires, such as the RG3 and R350, shortening of the guide catheter is seldom required, but may sometimes be needed for retrograde cases via bypass grafts or apical collaterals.
If manufactured short guide catheters are not available, a 100 cm long guide can be shortened using the following technique ( Fig. 2.2 ) (see online video: ” How to shorten a coronary guide catheter “).
- a.
The guide catheter is inserted into the body to engage the target coronary artery and the length of the guide that is outside the femoral sheath is marked.
- b.
The guide is removed from the body and the marked segment is cut and removed ( Fig. 2.2A ).
- c.
A sheath (1 Fr size smaller than the guide catheter; i.e., 6 Fr sheath for a 7 Fr guide catheter, etc.) is cut to create a 3–4 cm connecting segment for the two guide pieces ( Fig. 2.2B and C ). Both ends of this connecting segment are flared with a dilator (of equal size to the guide) to facilitate insertion ( Fig. 2.2D ).
- d.
This connecting sheath segment is used to reconnect the proximal and distal guide catheter pieces minus the portion that was removed to shorten the guide ( Fig. 2.2E and F ; final result in Fig. 2.2G ). Placing a Tegaderm (3M) over the connection site may help prevent accidental disconnection.
A limitation of shortened guide catheters is that they have poor torque transmission during vessel engagement and guide manipulations (especially during long procedures).
2.3.3
Side Holes
For right coronary artery CTOs guide catheters with side holes ( Fig. 2.3 ) are commonly used (especially for proximal occlusions), because they can prevent pressure dampening, may allow antegrade flow into the vessel, and may decrease the risk for hydraulic dissection during antegrade contrast injection. In contrast, unprotected left main coronary arteries should not be engaged with side-hole guide catheters (with the exception of ostial left main CTOs), because suboptimal guide catheter position may not be recognized and may lead to decrease in antegrade left main flow, global ischemia, and hemodynamic collapse. Side-hole guides, may provide a false sense of security, as hydraulic dissections can still occur upon injection. Moreover, dampening of the pressure ensures that minimal antegrade flow is allowed, when antegrade dissection/reentry techniques are used, minimizing expansion of subintimal hematoma. Side holes also increase contrast volume and potentially degrade angiographic image quality. A strategy of thoughtful active guide manipulation is often chosen over use of side-hole guide catheters, depending on the preference and comfort of the operator.
If no side-hole guides are available, an 18G needle or a scalpel can be used to create side holes in the guide catheter, followed by careful flushing with saline before use. However, side holes made by hand may prevent advancement of a guide catheter extension within the modified guide and can also weaken the guide and lead to kinking.
2.3.4
Y-Connectors With Hemostatic Valves
CTO PCIs can be lengthy procedures and result in significant blood loss from the Y-connector. Using a Y-connector with a hemostatic valve (such as the Co-pilot, Abbott Vascular or Guardian, Vascular Solutions; Fig. 2.4 ) can help minimize blood loss from back bleeding (which is particularly important for larger guide catheters, such as 8 Fr) and is easier to use compared with standard rotating hemostatic valves.
2.3.5
Guide Catheter Extensions
Three guide catheter extensions are currently available in the United States: the GuideLiner V3 catheter (Vascular Solutions, Fig. 2.5 ), the Trapliner (Vascular Solutions, Fig. 2.6 ) and the Guidezilla II (Boston Scientific, Fig. 2.7 ). The Trapliner is a rapid exchange guide catheter extension with a guidewire trapping balloon. Another guide catheter extension, the Guidion (Interventional Medical Device Solutions, Fig. 2.8 ) is available in Europe ( Table 2.2 ).
| Name | Sizes (Fr) | Internal Diameter | Total Length (cm) | Distal Cylinder Length |
|---|---|---|---|---|
| GuideLiner V3 | 5 5.5 6 7 8 | 0.046″ (1.17 mm) 0.051″ (1.30 mm) 0.056″ (1.42 mm) 0.062″ (1.57 mm) 0.071″ (1.80 mm) | 150 | 25 cm XL: 40 cm |
| Trapliner | 6 7 8 | 0.056″ (1.42 mm) 0.062″ (1.57 mm) 0.071″ (1.80 mm) | 150 | 13 cm |
| Guidezilla II | 6 7 8 | 0.057″ (1.45 mm) 0.063″ (1.60 mm) 0.072″ (1.83 mm) | 145 | 25 cm XL: 40 cm |
| Guidion | 5 6 7 8 | 0.041″ (1.04 mm) 0.056″ (1.42 mm) 0.062″ (1.57 mm) 0.071″ (1.80 mm) | 150 | 25 cm |
All guide catheter extensions consist of a push rod and a distal cylinder (25 cm in the GuideLiner V3 and the Guidezilla II, and 13 cm in the Trapliner) that are advanced into the coronary vessel. They are manufactured in various sizes ( Table 2.2 ) to fit various guide catheters, resulting in an inner diameter that is approximately 2 Fr smaller than that of the guide catheter. In addition to the rod and cylinder, the Trapliner also has a balloon proximal to the proximal collar that allows trapping of equipment ( Fig. 2.6 ).
- 1.
To minimize the risk of the guidewire wrapping around the guide catheter extension shaft, after inserting the guide catheter extension the external push rod should be placed into a towel at the side of the Y-connector ( Fig. 2.9 ).
Figure 2.9
(A) Guide catheter extension manipulation to minimize the risk for guidewire wrap-around. (B) Photo from Chad Kugler showing how to angle the guideliner away from the wire in a stationary position to avoid wire wrap inhibiting balloon/stent entry into the back of the guideliner.
- 2.
Advancing the guide catheter extension may be easier to achieve by inflating a balloon halfway inside the distal part of guide catheter extension cylinder and the vessel ( Fig. 2.10 ). The guide catheter extension is then advanced upon balloon deflation. Advancement over a balloon catheter or microcatheter is preferred to advancement over a 0.014″ coronary wire to minimize the risk of catching a plaque edge and causing a dissection (see Online Case 44 ).
Figure 2.10
Delivery of a guide catheter extension to the target coronary segment using a balloon.
- 3.
Guide catheter extension advancement may also be facilitated by use of a dedicated dilator (GuideLiner Navigation catheter, Vascular Solutions, Figs. 2.11 and 2.12 ).
Figure 2.11
Illustration of the Navigation catheter.
Figure 2.12
Delivery of a guide catheter extension to the target coronary segment using the Navigation catheter (Vascular Solutions).
- 4.
Deformation of guidewires, stents, or other equipment can occur during advancement through the guide catheter extension collar ( Fig. 2.13A ). To avoid this, it may be necessary in some cases to advance the stent or other equipment into the guide extension catheter outside the body and then introduce everything as a single unit into the guide catheter, or use fluoroscopic guidance to visualize the stent as it enters the guide catheter extension collar.
Figure 2.13
Complications of stent delivery through guide catheter extensions. (A) Stent deformation while attempting to deliver it through a GuideLiner catheter. (B) Stent deformation while attempting to retrieve an undeployed stent into the distal tip of a Guidezilla catheter. The tip of the Guidezilla prolapsed on itself ( arrow ) during attempted stent retrieval, resulting in catching the proximal edge of the stent and causing deformation ( arrowhead ).
(A) Reproduced with permission from Papayannis AC, Michael TT, Brilakis ES. Challenges associated with use of the GuideLiner catheter in percutaneous coronary interventions. J Invasive Cardiol 2012; 24 :370–71; (B) Courtesy of Dr. William Nicholson.
- 5.
Deformation of stents or other equipment can also occur while withdrawing the equipment back into the distal tip of the catheter after a failed attempt to advance to the target lesion, as shown in Fig. 2.13B .
- 6.
Attempts to advance guidewires through a guide that contains a guide catheter extension smaller than the size of the guide (e.g., a 6 Fr extension within an 8 Fr guide) should be avoided, as the wire is likely to advance between the guide catheter extension cylinder and the guide catheter wall.
- 7.
Deep advancement of the guide catheter extension may cause coronary dissection.
- 8.
During retrograde interventions, a guide catheter extension can be advanced through the antegrade guide catheter to facilitate the reverse controlled antegrade and retrograde tracking and dissection (CART) technique (“GuideLiner Reverse CART,” as described in Chapter 6 , Fig. 6.27 ). Guide catheter extensions can also be used from the retrograde side to increase support for retrograde gear delivery.
- 9.
Every effort should be undertaken to minimize pressure dampening, but if dampening occurs, it is important to verify that adequate antegrade flow is preserved and no vessel injury has occurred before proceeding with the intervention. Injection through a guide catheter extension with dampened pressure waveform may cause dissection that can propagate either antegrade or retrograde ( Fig. 2.14 ). It is important to hold the guide catheter extension shaft during forceful contrast injection to minimize the risk of ejecting the guide catheter extension!
Figure 2.14
Retrograde dissection caused by contrast injection through a guide catheter extension with dampened waveform (also video is provided, click here). (A) Guide catheter extension with its tip ( arrow ) deep-seated into the circumflex artery. (B) Retrograde dissection into aortic root ( arrow ) from contrast injection through the deep seated guide catheter extension.
- 10.
Although distal to proximal stenting is preferred, proximal to distal stenting can be done if needed, followed by insertion of the guide catheter extension through the proximal stent to allow distal stent delivery.
- 11.
Although coaxial alignment of the guide catheter is ideal, the guide catheter extension may be particularly effective in facilitating vessel engagement and equipment delivery when guide coaxial alignment is not possible, for example in anomalous coronary arteries ( Fig. 2.15 ). Distal anchoring (or use of the balloon technique shown in Fig. 2.10 or the Navigation catheter shown in Fig. 2.12 ) may be needed to deliver the guide catheter extension in such cases.
Figure 2.15
Use of the GuideLiner catheter for treating a CTO of an anomalous right coronary artery. (A) Chronic total occlusion ( arrow ) of an anomalous right coronary artery arising from the left sinus of Valsalva. (B) A GuideLiner catheter was placed over a Fielder guidewire with the support of an uninflated balloon kept in the proximal right coronary artery for better support. (C) The CTO was crossed with Confianza Pro 9 wire with the support of the GuideLiner. (D) Successful recanalization of the right coronary artery with TIMI 3 flow.
Reproduced with permission from Senguttuvan NB, Sharma SK, Kini A. Percutaneous intervention of chronic total occlusion of anomalous right coronary artery originating from left sinus – use of mother and child technique using GuideLiner. Indian Heart J 2015; 67 (Suppl. 3):S41–42, Elsevier Publication.
- 12.
The proximal collar of the guide catheter extension should not be advanced outside the guide catheter.
- 13.
Because the guide catheter extension decreases the original guide size by 2 Fr, special attention to pressure dampening and to activated clotting time (ACT) is needed to decrease the risk of thrombus formation.
- 14.
Trapping of equipment using a guide extension is difficult: (a) the trap balloon needs to be placed proximal to the proximal collar and (b) the equipment needs to be retracted to this location in order for successful trapping to occur. The Trapliner provides a clever solution to this problem by incorporating the trapping balloon into its push rod.
- 15.
Guide catheter extensions are very flexible and can advance even through highly tortuous lesions.
- 16.
Two guide catheter extensions can be used simultaneously in a mother–daughter–granddaughter configuration (i.e., a 6 Fr extension through an 8 Fr extension) when multiple extreme bends need to be navigated, for example when performing PCI through angulated saphenous vein grafts ( Fig. 2.16 ) ( Online Case 87 ).
Figure 2.16
Illustration of the “mother–daughter–granddaughter” technique. (A) Diagnostic angiography demonstrating lesions in the distal right coronary artery (arrows), which was very tortuous. (B) A 6 Fr GuideLiner (arrowhead) is advanced inside an 8 Fr GuideLiner (arrow) into the guide catheter. (C) The 6 Fr GuideLiner (arrowhead) and the 8 Fr GuideLiner (arrow) are advanced into the right coronary artery. (D) The 6 Fr GuideLiner (arrowhead) is advanced past the distal right coronary artery lesion. (E) A stent (arrow) is delivered through the “mother–daughter–granddaughter” system to the distal right coronary artery. (F) Excellent final result after stent implantation.
Courtesy of Dr. William Nicholson.
2.4
Microcatheters and Support Catheters
Antegrade CTO crossing should always be attempted using an over-the-wire system, i.e., a microcatheter or an over-the-wire balloon, because such a system:
- a.
Provides better support and increases wire tip stiffness, enhancing its penetration capacity ( Fig. 2.17 ).
Figure 2.17
Change in guidewire tip stiffness with various guidewire lengths extending past a microcatheter tip.
Reproduced with permission from Waksman, Saito. Chronic total occlusions: a guide to revascularization. Wiley-Blackwell; 2013.
- b.
Allows reshaping of the guidewire tip.
- c.
Allows easy guidewire exchanges.
- d.
Protects the proximal part of the vessel from guidewire-induced injuries.
Microcatheters are preferred to over-the-wire balloons as they allow accurate visualization of their tip location (because the marker is located at the tip, whereas in small balloons (1.20–1.50 mm in diameter) the marker is located in mid-shaft and the tip is not angiographically visible ( Fig. 2.18 ).
Several microcatheters and support catheters are commercially available ( Table 2.3 ). Some of the more commonly used microcatheters in CTO PCI are the following: Corsair, Corsair Pro, and Caravel (Asahi Intecc); Turnpike, Turnpike LP, Turnpike Spiral, and Turnpike Gold (Vascular Solutions); Finecross (Terumo); and Micro 14 (Roxwood Medical). Support catheters, such as the MultiCross and CenterCross (Roxwood Medical) are also available to increase the support of the guidewire and/or microcatheter during antegrade crossing attempts.
| Manufacturer | Catheter | Length | Distal Shaft Outer Diameter |
|---|---|---|---|
| Microcatheters | |||
| Asahi Intecc | Tornus | 135 cm | 2.1 and 2.6 Fr |
| Corsair and Corsair Pro a | 135 cm, 150 cm | 2.6 Fr | |
| Caravel a | 135 cm, 150 cm | 1.9 Fr | |
| Boston Scientific | Renegade 18 | 105 cm, 115 cm, 135 cm | 2.5 Fr |
| Mamba | 135 cm | 2.3 Fr | |
| Mamba Flex | 135 cm, 150 cm | 2.1 Fr | |
| Cordis | Transit | 135 cm | 2.5 Fr |
| Prowler | 150 cm | 1.9 Fr | |
| IMDS | NHancer Rx b (dual lumen) | 135 cm | |
| NHancer ProX b | 135 cm, 155 cm | 2.3 Fr | |
| Kaneka | Crusade b (dual lumen) | 140 cm | 1.3 Fr distal tip 3.1 Fr crossing profile |
| Mizuki b | 135 cm, 150 cm | 1.8 Fr distal tip 2.5 Fr shaft | |
| Mizuki FX b | 135 cm, 150 cm | 1.7 Fr distal tip 2.5 Fr shaft | |
| Roxwood | MicroCross 14 and MicroCross 14 es | 155 cm | 1.6 Fr |
| Spectranetics | Quick Cross | 135 cm, 150 cm | 2.0 Fr |
| Terumo | Progreat | 110 cm, 130 cm | 2.4 and 2.7 Fr |
| Finecross MG a | 130 cm, 150 cm | 1.8 Fr | |
| FineDuo b (dual lumen) | 140 cm | ||
| Vascular Solutions | Minnie | 90 cm, 135 cm, 150 cm | 2.2 Fr |
| SuperCross | 130 cm, 150 cm With preformed tip angle options of straight, 45, 90, or 120 degrees | 2.1 Fr | |
| Venture | 145 cm (rapid exchange) 140 cm (over-the-wire) | 2.2 Fr | |
| Twin Pass and Twin Pass Torque (dual lumen) | 140 cm | 1.9 Fr distal tip 3 Fr crossing profile | |
| TurnPike a | 135 cm 150 cm | 2.6 Fr | |
| TurnPike LP a | 135 cm 150 cm | 2.2 Fr | |
| Turnpike Spiral a | 135 cm 150 cm | 3.1 Fr | |
| Turnpike Gold | 135 cm | 3.2 Fr | |
| Volcano | Valet | 135 cm 150 cm | 1.8 Fr shapeable distal tip |
| Support Catheters | |||
| Roxwood Medical | MultiCross | 135 cm | |
| Roxwood Medical | CenterCross | 135 cm | |
| Radius Medical | Prodigy | 125 cm | |
| Nitiloop | NovaCross | 135 cm | |
2.4.1
Over-the-Wire Balloons
Either a microcatheter or an over-the-wire balloon can be used to support antegrade CTO PCI. In general microcatheters are preferred because:
- a.
They allow better understanding of distal tip position (a marker is placed at the microcatheter tip, whereas in small balloons the marker is located in the middle of the balloon) ( Fig. 2.18 ).
- b.
Are more flexible and track better than over-the-wire balloons.
- c.
Have less tendency to kink than over-the-wire balloons (kinking of balloon shaft prohibits future wire exchanges and often necessitates balloon catheter and wire removal and replacement with new gear, losing the crossing progress achieved). Over-the-wire balloons, however, may provide better support than many microcatheters.
2.4.2
Corsair and Corsair Pro
The Corsair microcatheter (Asahi Intecc, Fig. 2.19 ) was developed as a septal channel dilator to facilitate retrograde CTO PCI. The Corsair proprietary Shinka shaft is constructed with eight thin wires wound with two larger wires, which facilitate torque transmission ( Fig. 2.19 ). The inner lumen is lined with a polymer that enables contrast injection and facilitates wire advancement. The distal 60 cm of the catheter are coated with a hydrophilic polymer to enhance crossability. The tip is tapered and soft and is loaded with tungsten powder to enhance visibility. A platinum marker coil is placed 5 mm from the tip.
In the Corsair Pro ( Fig. 2.20 ) the distal radiopaque marker band was removed, the tip flexibility was increased, and the hub was redesigned to encompass the proximal section of the catheter, reducing the likelihood for wire kinking and entrapment.
- 1.
Two Corsair lengths are currently available (135 cm long with light blue proximal hub and 150 cm long with dark blue proximal hub).
- 2.
The Corsair can be used in the antegrade direction for wire support and exchange (usually the 135 cm length).
- 3.
The Corsair is initially advanced by pushing; if difficulty in advancement is encountered then rotation of the catheter starts. Rotation of the catheter should be avoided when not needed, to reduce the risk for Corsair fatigue.
- 4.
The Corsair catheter can be advanced by rotating in either direction, although it is braided to have better torque transmission with counterclockwise rotation. If resistance is encountered, a counterclockwise rotation combined with forward push is the most powerful maneuver. However, the Corsair should not be overrotated (>10 consecutive turns without release), as overrotation could cause catheter deformation and entrapment, fracture proximal to the catheter tip, or result in the wire binding to the microcatheter (Corsair fatigue) ( Fig. 2.21 ).
Figure 2.21
Images of the tip of a Corsair catheter permanently bound to a Pilot 200 guidewire with destruction of the wire’s polymer jacket and entanglement of the wire coil by the tip of the Corsair catheter.
Courtesy of Dr. William Nicholson.
- 5.
Rotation of the catheter with both hands and gentle antegrade pressure while the guidewire is kept in stable position allows for displacement of friction and tracking along the guidewire. This maneuver should be performed with pinning of the guidewire with the little finger to avoid inadvertent advancement. Advancing a Corsair retrogradely across a septal collateral may take several minutes (see Chapter 6 , step 6 on options when a microcatheter does not advance through a collateral channel).
- 6.
Contrast can be injected through the Corsair for distal vessel visualization, but the catheter should subsequently be flushed to minimize the risk for guidewire stickiness. Rarely the wire may get stuck, requiring removal of both Corsair and guidewire.
- 7.
If difficulty is encountered while attempting to advance the Corsair catheter after prolonged use, the cause may be Corsair fatigue, and you should consider exchanging for a new Corsair. Also the Corsair tip may become flared and advance poorly, also requiring exchange for a new catheter ( Chapter 6 , step 6).
- 8.
After wire externalization and during antegrade gear delivery, the tip of antegrade equipment (such as balloons and stents) should never come in contact with the tip of the retrograde Corsair catheter over the same guidewire to avoid interlocking and equipment entrapment (as described in Chapter 6 Step 9 and in Chapter 12 ).
2.4.3
Caravel
The Caravel microcatheter ( Fig. 2.22 ) was developed to advance through small and tortuous collaterals. It has a very low distal tip profile (1.4 Fr) and low distal shaft profile (1.9 Fr) with a hydrophilic coating. It also has a braided shaft. It was designed to advance with forward push, but could also be rotated to cross challenging collaterals. However, the Caravel was not designed to withstand aggressive rotation and advancement. Such an approach can strain the distal tip connection to the shaft of the microcatheter and result in fracturing off its tip ( Fig. 2.23 ) ( Online Case 87 ).
2.4.4
Finecross
The Finecross (Terumo) microcatheter is very flexible and has a low crossing profile (1.8 Fr distal tip). The Finecross catheter has a stainless steel braid (to enhance torquability) and a distal marker located 0.7 mm from the tip ( Fig. 2.24 ).
- 1.
The Finecross catheter is very flexible and navigates well through tortuosity.
- 2.
Although this catheter is mainly advanced using forward push, many operators are using a combination of push and rotation to facilitate advancement.
- 3.
The Finecross catheter (as well as the Corsair, Caravel, and Turnpike microcatheters) cannot be used for delivering 0.018 inch coils ( Section 2.10.2 ). Delivery of such coils requires a larger microcatheter, such as the Progreat (2.4 Fr, Terumo), Renegade (2.5 Fr, Boston Scientific), and Transit (2.5 Fr, Cordis).
- 4.
The Finecross is particularly useful when gear has been successfully advanced retrogradely to the target vessel, but progression of the initial microcatheter is unsuccessful within the body of the CTO vessel. The lower profile of the Finecross may be successful in advancing past the fibro-calcific obstacle impeding advancement of the initial microcatheter.
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