Balloon uncrossable and balloon undilatable lesions

23.1.1

Small balloon

• The first step when trying to cross a balloon uncrossable lesion is to use a small balloon ( Section 30.9.2 ).

• Use single marker, rapid exchange compliant balloons with a low crossing profile (1.0, 1.20, 1.25, and 1.5 mm in diameter) and long length (20–30 mm). The balloon profile is highest at the marker segment, hence longer balloons may allow for deeper lesion penetration with the lower profile segment of the balloon before the balloon marker reaches the uncrossable segment of the lesion. The Blimp Balloon (IMDS, not available in the United States) may also help crossing such lesions.

• The Sapphire Pro 1.0 mm (OrbusNeich), the Ryurei 1.0 mm (Terumo, not available in the United States), the Ikazuchi Zero (Kaneka, not available in the United States) and the NIC Nano 0.85 mm balloon (SIS, not available in the United States) are the lowest-profile balloons currently available and are, thus, the first choice for balloon uncrossable lesions.

• Other options are the Threader (1.2 mm, Boston Scientific) and the Takeru (Terumo) balloon that have low crossing profiles and stiff shafts to facilitate advancement though challenging lesions.

• The Threader (Boston Scientific) has a hydrophilic coating and 0.017 in. lesion entry profile. The Threader is available in both rapid exchange and over-the-wire versions. The rapid exchange Threader is preferred to the over-the-wire version for balloon uncrossable lesions, as it has more penetrating capacity (likely due to stiffer shaft). However, the over-the-wire Threader allows guidewire changes and contrast injection.

• The Glider balloon (Teleflex) has a beveled tip and was developed to cross through the struts of stents during bifurcation stenting, but can also be useful in difficult to cross lesions, as it can be torqued to present alternative tip configurations to the lesion.

• The Blimp balloon ( Section 30.9.3.4 ) may also help cross some of the balloon uncrossable lesions.

• If the balloon stops advancing, it can be inflated while maintaining forward pressure. This may dilate the entry to the lesion and allow lesion crossing, sometimes even with the same balloon (“balloon wedge” technique).

• If the balloon fails to advance, consider balloon rotation. Avoid rotating more than two to three times in each direction so as to prevent the balloon from getting “stuck” on the guidewire.

• If the balloon fails to advance after inflation, the operator can reshape it using his or her fingers while applying vacuum, or try a new small balloon (balloons lose their original profile after inflation), or one manufactured by another company, as different crossing profile and tip characteristics may assist in crossing. Rapid exchange balloon catheters allow more pushability into the lesion.

• Alternatively, one can attempt crossing with a larger 2.5–3.0 mm diameter rapid exchange balloon. Sometimes inflation with a larger diameter balloon just proximal to the lesion will disrupt the architecture of the lesion entry enough to allow subsequent passage of a small profile balloon or microcatheter.

What can go wrong ?

• 1.

  Guide catheter and guidewire position can be lost during attempts to advance the balloon or microcatheter. Carefully monitor the guide catheter position and stop advancing if the guide catheter starts backing out of the coronary ostium or if the distal guidewire position is being compromised. Forceful back and forth balloon manipulation can cause ostial dissection, especially if there is a preexisting ostial lesion.

• 2.

  Injury of the distal target vessel can occur (dissection or perforation) due to significant distal guidewire movement (“see-saw” action of wire with forward push and retraction of the balloon), especially when stiff (such as Confianza Pro 12, Asahi) or polymer-jacketed (such as the Pilot 200, Abbott Vascular) guidewires are used.

• 3.

  Balloon entrapment can occur within the lesion, although this is highly unlikely.

23.1.2

Grenadoplasty (intentional balloon rupture; also called “balloon assisted microdissection” or “BAM”)

This is a simple, safe, and often effective technique, that is increasingly being used in the treatment algorithm for balloon uncrossable lesions .

How ?

A small (usually 1.0–1.5 mm) balloon is advanced as far as possible into the lesion and inflated at high pressure until it ruptures ( Fig. 23.2 ) . When the balloon ruptures, suction should immediately be applied through the inflating device to avoid unnecessary barotrauma to the vessel. The balloon rupture can often sufficiently modify the plaque, resulting in subsequent successful crossing with a new balloon.

What can go wrong ?

• 1.

  Proximal vessel dissection and perforation. This is extremely unlikely when small (1.0–1.5 mm) balloons are used. Larger balloons (≥ 2.0 mm) should NOT be used for grenadoplasty.

• 2.

  The balloon should be meticulously prepared to empty all air and hence minimize the risk of air embolism.

• 3.

  Watching the indeflator rather than the screen allows more rapid deflation of the balloon immediately upon rupture. This will reduce the chance of pinhole contrast-induced vessel injury from the rupture site of the balloon.

• 4.

  One may encounter difficulty removing the ruptured balloon. In some cases, the ruptured balloon becomes entangled with the guidewire, requiring removal of both, hence losing guidewire position.

23.1.3

Increase support

Increasing support is critical for crossing a balloon uncrossable lesion and is discussed in detail in Section 9.5.8. Key elements for increasing support are the guide catheter and the guidewire.

23.1.4

Microcatheter advancement

How ?

• 1.

  The concept behind use of a microcatheter is that advancement of a microcatheter through the lesion can modify the occlusion, enabling subsequent crossing with a balloon.

• 2.

  There are several microcatheters that can be utilized as described in Section 30.6 .

• 3.

  The following microcatheters are especially designed for balloon uncrossable lesions ( Section 30.6.5 ):

  • The Tornus catheter (Asahi Intecc) was designed for advancing through calcified and difficult to penetrate lesions and should be advanced using counterclockwise rotation and withdrawn using clockwise rotation .

  • The Turnpike Spiral and Turnpike Gold catheters (Teleflex) were also designed with threads to “screw into the lesion” and modify it. In contrast to the Tornus catheter, they are advanced by turning clockwise and withdrawn by turning counterclockwise.

• 4.

  Standard microcatheters can also be used:

  • The Corsair Pro and Corsair XS microcatheters (Asahi Intecc) ( Section 30.6.1 ) can be advanced by rotating in either direction (in contrast to the Tornus catheter).

  • The Turnpike and Turnpike LP catheters (Teleflex) ( Section 30.6.1 , Section 30.6.2 ) can also be rotated in either direction.

  • Similarly, the Finecross (Terumo) or MicroCross 14 (Boston Scientific) ( Section 30.6.2 ) can be rotated in either direction, although rotation may be challenging and there is a risk of tip dislodgement if aggressively torqued.

  • The Caravel (Asahi Intecc) is a low-profile microcatheter, but is not designed for aggressive torquing as is often done with the Corsair and Turnpike family of microcatheters and should generally not be used in balloon uncrossable lesions to minimize the risk of tip fracture and separation.

• 5.

  If successful advancement of a microcatheter is achieved, a balloon can often subsequently cross the lesion. Alternatively, the guidewire can be exchanged for a more supportive guidewire or an atherectomy wire ( PCI Manual Online case: 64 ), if the latter is planned as the next lesion preparation step.

What can go wrong ?

• 1.

  Guide catheter and guidewire position may be lost with aggressive pushing of the microcatheters.

• 2.

  Distal vessel injury can occur from uncontrolled guidewire movement during microcatheter advancement attempts.

• 3.

  The microcatheter can get damaged if overtorqued, leading to catheter tip entrapment or tip/shaft fracture. If the tip of the microcatheter breaks off it can become entrapped in the lesion. Rotation should not exceed 10 turns before allowing the catheter to “unwind.” A guidewire should always be kept within the microcatheter lumen to prevent kinking and possible entrapment. If the tip of the microcatheter breaks off it can become entrapped in the lesion.

• 4.

  Rarely, excessive manipulation of the microcatheter can disrupt the device and/or the guidewire and lock both devices together, requiring withdrawal of both. A polymer-jacketed guidewire can sometimes be advanced through the track that has been established, allowing the crossing attempts to restart.