Analysis of the long-term effects of drug-eluting stents on coronary arterial wall morphology as assessed by virtual histology intravascular ultrasound.

BACKGROUND: Animal models show impairment of arterial healing after drug-eluting stents (DES) compared with bare-metal stents (BMS). Virtual histology intravascular ultrasound (VH-IVUS) offers an opportunity to assess lesion morphology in vivo. METHODS: We used VH-IVUS in 80 patients to assess long-term (median = 10 months) native artery vascular responses after 76 implantations of DES compared with 32 BMS. The presence of "necrotic core abutting the lumen" was evaluated at baseline and follow-up. RESULTS: At baseline, necrotic core abutting the lumen through the stent struts was observed in 76% of DES and 75% of BMS. Although the percentage of necrotic core within the plaque behind the stents did not change during follow-up in DES (23% [18%, 28%] to 22% [17%, 27%], P = .57) or BMS (22% [19%, 27%] to 20% [12%, 26%], P = .29), necrotic core abutting the lumen through the stent struts decreased more in BMS (75% to 19%, P < .001) than DES (76% to 61%, P = .036) because of the lack of an overlying, protective neointima in DES-treated lesions. Furthermore, within the adjacent reference segments, the incidence of necrotic core abutting the lumen decreased in BMS-treated lesions (proximal 23% to 0%, P = .023; distal 21% to 0%, P = .023), but not in DES (proximal 22% to 17%, P = .48; distal 23% to 21%, P = .82). CONCLUSIONS: Serial VH-IVUS analysis of DES-treated lesions showed a greater frequency of unstable lesion morphometry at follow-up compared with BMS. The apparent mechanism was a suppression of the protective neointimal hyperplasia layer coupled with a lack of vulnerable plaque resolution at reference segments in DES compared with BMS.

Reestenose de stents coronarianos: resultados imediatos e tardios do tratamento com excimer laser / In-stent restenosis: acute and long-term outcomes after excimer laser coronary angioplasty

Objective - With the increased use of intracoronary stents, in-stent restenosis has become a clinically significant drawback in invasive cardiology. We retrospectively assessed the short-and long-term outcomes after excimer laser coronary angioplasty of in-stent restenosis. Methods - Twenty-five patients with 33 incidents of in-stent restenosis treated with excimer laser coronary angioplasty (ELCA) were analyzed. Sixty-six percent were males, mean age of 73+ 11 years, and 83 per cent were functional class III-IV (NYHA). ELCA was performed using 23 concentric and 10 eccentric catheters with a diameter of 1.6-2.2 mm, followed by balloon angioplasty (PTCA) and untrasound monitoring. The procedure was performed in the following vessels: left anterior descending artery, 10; left circunflex artery, 8; right coronary artery, 6; left main coronary artery; 2 and venous bypass graft, 7. Results - The ELCA was successful in 71 per cent of the cases, and PTCA was 100 per cent successful. The diameter of the treated vessels was 3.44+0.5 mm; the minimal luminal diameter (MLD) increased from 0.30mm pre-ELCA to 1,97mm post-ELCA, and to 2.94mm post-PTA (p<0.001). The percent stenosis was reduced from 91.4+9.5 per cent before ELCA to 42.3+14.9 per cent after ELCA and to 14.6+9.3 per cent after PTCA (P<0.001). Seventeen (68 per cent) patients were asymptomatic at 6 months and 15 (60 per cent) at 1 year. New restenosis rates were 8/33 (24.2 per cent) at 6 months and 9/33 (27.3 per cent) at 12 months. Conclusion - ELCA is safe effective for the treatment of in-stent restenosis. In the present sample, a slight increase in new restenotic lesions between 6 and 12 months was found.