Guide Catheter Selection

For the RCA aorto-ostial lesion, standard right Judkins catheters often cannot provide satisfactory device support. Configurations such as modified Amplatz (left or right), multipurpose, Arani, or El Gamal catheters have been used successfully. Ostial lesions, especially of the RCA, may be occluded during seating of the guide catheter, as seen by damping of arterial pressure. Damping requires guide catheters with side holes to permit some perfusion during equipment maneuvers. While adequate for coronary perfusion after re-establishment of a patent lumen, side holes may limit coronary visualization (contrast escapes through side holes), especially when using large devices (e.g., Rotablator).

Careful engagement of the guide catheter should minimize aortic trauma and avoid an ostial dissection which would complicate an already difficult procedure. The use of Rotablator catheters requires nearly coaxial alignment of the guide catheter upon device entry in the ostium. Significant angulation between the guide catheter and the ostial takeoff will reduce procedure success.

Balloon Catheter Placement

Balloon angioplasty requires seating such that, during inflation, the balloon will not be ejected from, nor compressed forward past (“watermelon seed”), the coronary ostia (Fig. 11-1). Removal of the guide catheter into the aorta immediately before balloon inflation will permit the balloon to be inflated partly in the coronary ostium and the aorta and outside the guide catheter. The lesion will be appropriately spanned by the two ends of the balloon inflating at equal pressure. Inflation in the guide may result in failure of the distal end of the balloon to inflate properly. Stenting the ostial lesion may produce strut “hangout” into the main vessel, a common complication of ostial branch stenting, especially when angiographic angles do not allow good visualization of the takeoff. An anchor wire technique may obviate this problem.

Figure 11-1 A, Effect of squeezing the balloon out of an ostial lesion. The top panels show the balloon being ejected from the ostium, and the lower panels show the balloon advancing inside the artery during inflation. B, Proper guide catheter positioning helps to seat the balloon in an ostial lesion.

(Adapted from Safian R, Freed M, eds. The manual of interventional cardiology, 3 rd ed. Birmingham, MI: Physicians’ Press, 2001, p. 267.)

Figure 11-2 demonstrates good techniques for RCA ostial stenting. Recovering access to the main vessel after ostial stenting can be difficult depending on the angle of the ostium origin and the amount of stent. It may be helpful to leave the stent balloon catheter in place and advance the guide catheter over the balloon to minimize damage or disfiguration of the recently implanted stent.

Figure 11-2 Aorto-ostial lesions: stent technique. A, Position the stent-delivery balloon so 1 to 2 mm of stent extends into the aorta. The guide must be retracted 1 to 2 cm before deploying the stent. B, Remove the delivery balloon while maintaining backward tension on the guide, to prevent it from advancing into the ostium and damaging the stent. C, Perform adjunctive percutaneous transluminal coronary angioplasty with a high-pressure balloon to ensure full stent expansion and apposition. Flaring the proximal end of the stent with a slightly larger balloon is useful. D, Final result.

(From Freed M, Grines C, Safian R, eds. The new manual of interventional cardiology. Birmingham, MI: Physicians’ Press, 1996.)

The Back-Stop Technique

A strategy to prevent strut hangout uses a main vessel balloon inflated at low pressure (balloon:artery ratio 0.7:1), placed prior to branch stent deployment (Fig. 11-3). By pulling the ostial stent back against the inflated balloon and then deploying the stent, one prevents significant strut hangout into the main vessel.

Figure 11-3 A, Back-stop technique for ostial stenting. B, Subtotal ostium of the posterior left ventricular (PLV) branch with an uninvolved posterior descending artery (PDA) at the bifurcation. C, Both vessels wired and undersized balloon is positioned across ostial PLV. D, PLV ostium is predilated. The balloon is then removed, reshaped, and inserted into the PDA for an undersized balloon backstop inflation. E, The undersized balloon is inflated in the PDA at low pressure. The stent is seated in the PLV and gently pulled back until a slight resistance is felt against the balloon in the PDA. The stent is then inflated at optimal atmospheres. The stent is deflated, and following deflation, the balloon is then deflated. F, Ostial PLV stent wall opposition is maximized, while PDA is protected from plaque encroachment. Barotrauma causing neointimal hyperplasia is minimized in the PDA by the undersized balloon at low inflation atm. The proximal RCA was treated by a direct stent.

(Modified from Lunsford C. Advanced stenting strategies for complex coronary artery bifurcation lesions. Cath Lab Digest, June 19, 2008.)

For moderately or severely calcified lesions, rotational atherectomy is the technique of choice, followed by stenting.

The Szabo Technique for Precise Ostial Stent Placement

Precise localization of the edges of the ostium of any coronary artery or branch is among the most challenging of all angiographic image interpretations. Due to the limitations of angiographic imaging, there is commonly unavoidable stent overlap either too far inside or outside the ostium. Stents placed outside the true ostium may obstruct later catheter engagement, whereas stents inserted too deeply may miss the proximal edge of the lesion, resulting in a need for another stent or later restenosis.

In 2005, a technique to accurately place the stent and anchor it from advancing beyond the ostium of a lesion using a second angioplasty guidewire positioned in the aorta or opposing branch was reported. The technique using the most proximal end of a second guidewire passing it through the last cell of the stent inhibiting advancement and anchoring the stent position was first described in an abstract at the Transcatheter Cardiovascular Therapeutics conference by Szabo et al., but never brought forward into full publication. Our lab, and later others, described several cases for anchoring both the distal and proximal portions of the stent with the Szabo wire technique. The Szabo technique for aorto-ostial lesions (Fig. 11-4) and for bifurcation ostial lesions is described below:

Figure 11-4 A, Aorto-ostial stent placement with the Szabo technique. B, Ostial bifurcation stent placement with the Szabo technique. C, LAD-LCX bifurcation stent placement with the Szabo Technique.

While now in use for several years, there are several safety factors related to the use of the anchor wire method that should be considered:

Other methods to assist in the exact ostial stent placement, such as metal spring feet on the end of the guide catheter (Ostial Pro), are emerging but the Szabo anchor wire technique appears to be an easy and cost-effective method for precise ostial lesion stenting.