Serial angiographic follow-up after Palmaz-Schatz stent implantation: comparison with conventional balloon angioplasty.

OBJECTIVES

Serial angiographic follow-up study was designed to evaluate the temporal mode of lumen diameter changes after Palmaz-Schatz stent implantation, and the results were compared with those from a cohort of patients undergoing balloon angioplasty.

BACKGROUND

Restenosis remains a major limitation of balloon angioplasty. The Palmaz-Schatz balloon expandable coronary stent is now under clinical investigation to evaluate its efficacy in preventing restenosis.

METHODS

Serial angiographic follow-up study was performed the day after stent implantation and at 1, 3 and 6 months after the procedure. The stent group consisted of 96 patients who had 97 lesions with a single stent. A cohort of 179 patients with 192 lesions were selected as the balloon group by the criteria of final balloon size > or = 3 mm and lesion length < 20 mm.

RESULTS

A significantly larger lumen diameter was obtained immediately after stent implantation (2.9 +/- 0.4 mm [mean +/- SD] in the stent group vs. 2.1 +/- 0.5 mm in the balloon group, p < 0.001). At 3 to 6 months of follow-up, a significantly larger lumen diameter was maintained in the stent group (2.2 +/- 0.6 vs. 1.5 +/- 0.7 mm, p < 0.001). The late restenosis rate according to a binary definition was significantly lower in the stent group (13% vs. 39%, p < 0.001). Stenosis exacerbation, frequently observed within 24 h after balloon angioplasty, was not found after stenting. Between the next day and 1 month, regression was dominant in the balloon group, whereas progression of stenosis was observed in the stent group. The greatest tendency to restenosis was observed in both groups between 1 and 3 months after the procedure. Between 3 and 6 months, significantly greater diameter loss was found in the stent group.

CONCLUSIONS

The Palmaz-Schatz stent was effective in reducing the restenosis rate in this highly selected cohort of patients. Reduction in restenosis rate was dependent on a larger lumen obtained immediately. Late loss of diameter was significantly greater after stenting. The restenosis rate after stenting should be evaluated by follow-up angiography at 6 months rather than at 3 months, which is adequate after conventional balloon angioplasty.