Catheterization and Cardiovascular Diagnosis 37:73-75 (1996)

Technical Considerations in Deploying the Sheathed Palmaz-Schatz Stent in Distal Coronary Artery and Bypass Graft Lesions

Rajiv Agarwal, MD, DM, Upendra Kaul, MD, DM, and Pradeep Jain, MD, DM

The deliverable catheter length of the Palmaz-Schatz stent de- livery system is significantly limited by the protective sheath and clamshell device. This limitation must be considered when planning distal stent placement, especially in bypass gralt le- sions. A technique for shortening the guide catheter without losing guidewire position is described.

Key words: percutaneous transluminal coronary angioplasty, guide catheter, guidewire, balloon catheter

o 1996 Wiley-Liss, Inc.

INTRODUCTION

Standard length guide catheters and balloon catheters for percutaneous transluminal coronary angioplasty (PTCA) may not be able to reach distal lesions, espe- cially in long venous and arterial grafts [l]. Various modifications have been proposed to overcome this prob- lem, including shorter guide catheters and balloon cath- eters with longer shafts made to order. Alternatively, the guide catheter may be cut to reduce its length. This prob- lem is especially relevant to the Palmaz-Schatz stent pre- mounted on a stent delivery system (SDS), where the protective sheath and clamshell device reduce the actual usable length. We report one such case and our approach to its management.

CASE REPORT

A 65-yr-old man developed unstable angina 10 yr after coronary artery bypass surgery. He was taken for PTCA followed by elective stent placement for a complex ste- nosis in a sequential vein graft to the diagonal and obtuse

From the Department of Cardiology, All India Institute of Medical Sciences, New Delhi, India.

Received February 16, 1995; revision accepted May 1 , 1995

Address reprint requests to Rajiv Agarwal, M.D., Department of Car- diology, All India Institute of Medical Sciences, New Delhi 110 029, India.

marginal arteries beyond the diagonal anastomosis (Fig. 1 a). Written informed consent was obtained before per- forming the procedure.

An 8 French JR4 guide catheter (Illumen, USCI Di- vision, CR Bard, Billerica, MA) (100 cm long) was used to engage the graft. The lesion was dilated with a 2.75 mm Miniprofile balloon over a 0.014” Hi-Per Flex guidewire (both from CR Bard, Ireland, Galway, Ire- land). The balloon catheter had a usable length of 135 cm and reached the lesion easily. We then changed the guidewire to a 0.014”. Hi-Torque extra support wire (ACS, Temecula, CA) and elected a 3.5 mm Palmaz- Schatz sheathed stent (Johnson and Johnson Interven- tional Systems Co., Warren, NJ). The usable catheter length mentioned on the stent package was also 135 cm. However, the stent balloon catheter, with its protective sheath and clamshell device, was found to be too short to reach the lesion.

We then withdrew the stent system and cut the guide catheter with a scalpel blade 5 cm outside the femoral puncture site. Care was taken not to damage the guidewire, which was kept across the lesion throughout the procedure. An 8 French valved sheath (Bard Hema- quet I1 SV, CR Bard) was cut 2 cm from the hub, and the valved portion inserted over the guidewire to fit snugly over the guide catheter (Fig. 2). The stent system was then introduced over the guidewire directly through the valved sheath dispensing with the Tuohy Borst hemo- static valve. The lesion was reached easily and the stent deployed uneventfully and without complications. Post- procedure angiograms through the side arm of the valved sheath revealed an excellent result (Fig. lb).

DISCUSSION

The distance that a balloon catheter can travel down a coronary artery (deliverable catheter length) is deter- mined by the difference between the length of the guide catheter and the usable length of the balloon catheter. The Tuohy Borst hemostatic valve (7-9 cm long from various manufacturers) further reduces the deliverable catheter length. The Palmaz-Schatz stent delivery system is labeled as having a usable catheter length of 135 cm, which is similar to most balloons. However, this is po- tentially misleading since the combination of the protec- tive sheath and clamshell device reduce the usable length of the stent balloon catheter by another 15 cm (Fig. 3a). Thus the stent balloon cannot travel as far distally as a balloon with equivalent catheter length. This may create problems while placing stents in distal lesions, especially in bypass grafts. In the present case, the deliverable cath-

0 1996 Wiley-Liss, Inc.

74 Agarwal et al.

Fig. 1. (a) Complex thrombus containing stenosis in a sequential vein graft to the diagonal and obtuse marginal arteries (arrow). (b) Excellent angiographic result after PTCA and placement of a stent (arrow).

eter length of the balloon catheter used was 27 cm as compared with only 12 cm for the sheathed stent. Extra deliverable stent catheter length was gained by cutting the guide catheter and dispensing with the Tuohy Borst hemostatic valve as described earlier by Stratienko et al. [2] (Fig. 3b). Chan et al. [3] have described an alterna- tive technique for shortening the guide catheter using a prefabricated adaptor device. Such a device may not al- ways be available. The present method is simple and effective without requiring special equipment.

This case also demonstrates that the sheathed Palmaz- Schatz stent can be safely introduced through hemostatic valves without distortion. This was subsequently con- firmed in vitro by passing another sheathed Palmaz-

Fig. 2. Close-up view showing the cut end of the guide cathe- ter and a shortened valved sheath inserted over the guidewire.

Fig. 3. (a) Sheathed Palmaz-Schatz stent inserted through a Tuohy Borst hemostaic valve and guide catheter. The protective sheath and clamshell device reduce the deliverable catheter length of the stent delivery system (arrows). (b) Modified sys-

tem for stent delivery. By cuttlng the guide catheter and replac- ing the hemostatic valve with a shortened valved sheath, the deliverable catheter length (arrows) is greatly increased.

Schatz stent through a hemostatic valve without any damage. Such a manoeuver is certainly not recom- mended for bare stents mounted on balloon catheters.

The use of a valved sheath fitting snugly over the guide catheter prevented backbleed. The side arm al- lowed accurate pressure monitoring as there was no leak although the tracing was damped after introduction of the stent assembly. Excellent angiographic pictures could be obtained by contrast injection through the side arm of the sheath (Fig. lb). Slight flaring of the cut end of the guide catheter may enhance the tightness of this interface be- tween the cut ends of the guide catheter and hemostatic sheath, although it was not required in the present case.

SUMMARY

The severe curtailment of the deliverable catheter length of the Palmaz-Schatz stent delivery system on

Stent Placement in Distal Coronary Lesions 75

account of the protective sheath and clamshell device needs to be appreciated when planning stent placement. Package labeling of the Palmaz-Schatz stent should also reflect this limitation. A technique for shortening the guide catheter to gain extra length without losing guidewire position is described.

REFERENCES

Rozenbaum EA, Topaz 0, Wysham DG: Balloon catheter sys- tems for PTCA: The importance of the catheter length. Cathet Cardiovasc Diagn 28:252-255, 1993. Stratienko AA, Ginsberg R, Schatz RA, Tierstein PS: Technique for shortening angioplasty guide catheter length when therapeutic catheter fails to reach stenosis. Cathet Cardiovasc Diagn 30:33 I- 333, 1993. ChanRC, Rihal CS, Menke KK, Winter SJ, Holmes DR: Adaptor device for shortening guide catheters to access distal lesions in coronary angioplasty. Cathet Cardiovasc Diagn 30:249-25 I , 1993.