Objectives: The aim of the present study was to determine whether troglitazone reduces neointimal tissue proliferation after coronary stent implantation in patients with non-insulin dependent diabetes mellitus (NIDDM).
Background: Increased in-stent restenosis in patients with diabetes mellitus is due to accelerated neointimal tissue proliferation after coronary stent implantation. Troglitazone inhibits intimal hyperplasia in experimental animal models.
Methods: We studied 62 stented lesions in 52 patients with plasma glucose levels (PG) > or = 11.1 mmol/liter at 2 h after 75 g oral glucose load. The study patients were randomized into two groups: the troglitazone group of 25 patients with 29 stents, who were treated with 400 mg of troglitazone, and the control group of 27 patients with 33 stents. All patients underwent oral glucose tolerance tests before and after their six-month treatment period. The sum of PG (sum of PG) and the sum of insulin levels (sum of IRI) were measured. Serial (postintervention and at six-month follow-up) intravascular ultrasound studies were performed. Cross-sectional images within stents were taken at every 1 mm, using an automatic pullback. Stent areas (SA), lumen areas (LA), and intimal areas (IA = SA - LA) were measured and averaged over a number of selected image slices. The intimal index was calculated as intimal index = averaged IA/averaged SA x 100%.
Results: There were no differences between the two groups before treatment in sum of PG (31.35 +/- 3.07 mmol/liter vs. 32.89 +/- 4.87 mmol/liter, respectively, p = 0.2998) and sum of IRI (219.6 +/- 106.2 mU/liter vs. 209.2 +/- 91.6 mU/liter, respectively, p = 0.8934). However, reductions in sum of PG at the six-month follow-up in the troglitazone group were significantly greater than those in the control group (-21.4 +/- 8.8% vs. -4.5 +/- 7.4%, respectively, p < 0.0001). Likewise, decreases in sum of IRI were greater in the troglitazone-treated group (-31.4 +/- 17.9% vs. -1.9 +/- 15.1%, respectively, p < 0.0001). Although, there were no differences between the two groups in SA at postintervention (7.4 +/- 2.2 mm2 vs. 7.3 +/- 1.7 mm2, respectively, p = 0.9482) and at follow-up (7.3 +/- 2.3 mm2 vs. 7.3 +/- 1.8 mm2, respectively, p = 0.2307), the LA at follow-up in the troglitazone group was significantly greater than that in the control group (5.3 +/- 1.7 mm2 vs. 3.7 +/- 1.7 mm2, respectively, p = 0.0002). The IA at follow-up in the troglitazone group was significantly smaller than that in the control group (2.0 +/- 0.9 mm2 vs. 3.5 +/- 1.8 mm2, respectively, p < 0.0001). This was also true for intimal index (27.1 +/- 11.5% vs. 49.0 +/- 14.4%, respectively, p < 0.0001).
Conclusions: Serial intravascular ultrasound assessment shows that administration of troglitazone reduces neointimal tissue proliferation after coronary stent implantation in patients with NIDDM.