ABSTRACT: Tortuous or highly angulated vessels can sometimes be a hindrance to successful percutaneous coronary intervention while conferring an increased risk of major adverse events compared to lesions in nonangulated vessels. We present a case demonstrating the benefit of a recently available deflecting tip 0.014 inch guidewire to help negotiate an acute-angled takeoff of the left anterior descending artery from the left main coronary artery. This novel device proved successful, and as such, can complement the armamentarium of the modern-day interventionalist.

       Access to severely angulated coronary vessels and branches can represent a challenge, even for experienced interventionalists, and despite the use of modern highly steerable guidewires. Percutaneous treatment of such lesions also confers a higher chance of failure with increased risks of major adverse events compared to lesions in nonangulated vessels.¹ In the past, a number of deflectable-tip guidewire prototypes were developed such as the Versaflex (Medtronic, Inc., Minneapolis, Minnesota), but these lacked steerability and became too stiff at the tip. More recently, the Niobe guidewire incorporating a magnet at the tip steered by a powerful magnetic field (Stereotaxis, Inc., St. Louis, Missouri) has been used to navigate tortuous and angulated coronary lesions,² however this technique requires a costly large magnet built into the catheterization suite, and the wire mechanical characteristics still remain suboptimal. We present a case of a patient with prior coronary artery bypass grafting (CABG) and recent angina where angiography demonstrated a very angulated lesion in the distal left main (LM) and ostium of the left anterior descending artery (LAD) successfully crossed using the novel Steer-IT™ deflectable-tip guidewire (Cordis Corp., Miami, Florida).

Case Report

       A 73-year-old diabetic male with prior CABG (1987) and re-do CABG (1999) presented with 3 months of escalating angina on

Figure 1A

Figure 1. (A) Coronary angiography of the left anterior oblique with caudal angulation demonstrating a severe stenosis with extreme angulation in the distal left main and left anterior descending arteries.

effort. A thallium scan demonstrated inducible ischemia in the anterior myocardial wall and apex. Diagnostic

Figure 1B

(B) The Steer-IT guidewire (arrow) advancing across the stenosis in the left main and left anterior descending arteries with a combination of gentle pushing and progressive straightening of the distal curve using the handle.

angiography revealed an occluded left internal mammary artery graft to the LAD with a severe stenosis in the left main bifurcation and LAD arising at an acute angle from the left main (LM) artery (Figure 1A). The left circumflex artery (LCx) was occluded beyond the proximal segment with a patent vein graft maintaining perfusion in this territory.
       Using a 6 Fr Extra Back-Up 4.0 Launcher guide (Medtronic), multiple guidewires (Balance Middleweight Universal, Pilot 50, Whisper; Guidant Corp., Indianapolis, Indiana) were used with various primary/secondary curves at the tip, but even if the tip engaged the vessel, gentle pushing with and without rotation did not advance the wire and resulted in immediate prolapse into the LCx. Balloon support was unsuccessful. A Steer-IT deflectable-tip wire was advanced into the LCx immediately distal to the LAD origin and the tip was deflected and steered in the LAD with a combination of gentle pushing and progressive straightening of thedistal curve (Figure 1B). The wire was disconnected from the handle governing tip deflection and used throughout the procedure (predilatation, stent implantation of a 3.5 x 13 mm sirolimus-eluting stent [Cypher Select, Cordis] and postdilatation with a 4.0 mm balloon] (Figure 1C).

Discussion

       Prior attempts to develop deflectable-tip guidewires^3,4 have been met with poor steerability and torqueability, thereby

Figure 1C

(C) Final angiographic result following implantation of a 3.5 x 13 mm sirolimus-eluting stent and postdilatation using a 4.0 mm balloon.

precluding

Figure 1D

(D) The Steer-IT detachable handle. Deflection of the tip is controlled by advancing the actuator back and forth in a smooth motion. The torquer allows gentle rotation and control of the wire.

a more widespread use. The SteerIT device has recently become available for commercial use in Europe and the United States andincorporates a 0.014 inch nitinol Teflon-coated wire. The distal 7 mm tip of the wire can be manipulated to deflect in 2 planes using a detachable handle containing the actuator (Figure 1D). The tip can be directed to negotiate acute angles and tortuosity while maintaining many of the properties intrinsic to modern interventional guidewires including steerability, trackability and torque control (Figure 1E). Such features may also be advantageous in crossing jailed stent struts in bifurcation lesion interventions.
       Other than deflecting tip guidewires, catheter-based systems such as the Venture catheter (St. Jude Medical, Inc., St. Paul, Minnesota) may offer better support to a wire crossing angulated and tortuous vessels, preventing wire prolapse. Such a device also leaves the decision of which guidewire to use up to the operator.^5,6 Flexible over-the-wire catheters can also support the wire, but they are unlikely to track if only the very tip of the wire can be engaged.

Figure 1E

(E) The 7 mm deflectable tip is shown in its straight configuration and at maximum deflection.

       Devices that aid in negotiating difficult segments of a patient’s vasculature can improve the chances of a successful outcome. The device used in this report has the advantage of being bidirectional with its novel deflectable tip, while maintaining many of the properties an interventional cardiologist would expect from a guidewire. Such a device is therefore a useful contributor to the armamentarium of the modern interventional cardiologist.