Efficacy and safety of low-dose clopidogrel in Japanese patients after drug-eluting stent implantation: a randomized pilot trial.

In Japan, a lower maintenance dose of ticlopidine is used than in the United States and Europe. Therefore a lower maintenance dose of clopidogrel may also be considered appropriate in Japanese patients. The present randomized pilot study evaluated the efficacy and safety of 50 mg clopidogrel in Japanese patients who underwent drug-eluting stent (DES) implantation. A total of 200 patients with 277 lesions who underwent intravascular ultrasound-guided DES implantation were enrolled. The subjects were allocated to the 50- or 75-mg clopidogrel group. All patients received 100 mg aspirin daily before the procedure, and this continued indefinitely. The duration of clinical follow-up was 21.8 ± 5.7 months in the 75-mg group and 21.9 ± 6.1 months in the 50-mg group (P = 0.96). During follow-up, no cardiac death, myocardial infarction, or stent thrombosis was observed in either group. Side effects of clopidogrel were observed in 4 patients (4.0 %) in the 75-mg group and in 4 patients (4.0 %) in the 50-mg group. Following this randomized pilot study, it may be justified to perform a large-scale randomized study comparing 50- and 75-mg dosing of clopidogrel in Japanese patients undergoing coronary stent implantation.

Effects of stem cell mobilization by granulocyte colony-stimulating factor on endothelial function after sirolimus-eluting stent implantation: a double-blind, randomized, placebo-controlled clinical trial.

BACKGROUND: Stem cell mobilization by granulocyte colony-stimulating factor (G-CSF) has been shown to enhance endothelial healing after spontaneous or iatrogenic arterial disruption. Granulocyte colony-stimulating factor treatment might attenuate endothelial dysfunction after sirolimus-eluting stent (SES) implantation that may be associated with adverse cardiac events during follow-up. This prospective, double-blind, randomized, placebo-controlled study investigated whether G-CSF improved endothelial dysfunction after SES implantation. METHODS: One hundred patients who underwent SES implantation were randomly assigned to the G-CSF (n = 50) or the placebo group (n = 50). They received daily subcutaneous injection of 300 µg G-CSF or saline for 5 days. Endothelial function was estimated by measuring the coronary vasoreactivity in the segments 15 mm proximal and distal to SES in response to intracoronary infusion of acetylcholine (10(-8) and 10(-7) mol/L) at 9-month follow-up. RESULTS: Follow-up angiography was performed in 41 G-CSF patients (82%) and 46 placebo patients (92%) (P = .14). Changes in coronary diameter in response to acetylcholine infusion in the proximal segment were not significantly different between the 2 groups. However, vasoconstriction in the distal segment in response to 10(-8) mol/L (-3.9% ± 6.4% vs -7.0% ± 8.1%, P < .05) and 10(-7) mol/L (-8.8% ± 11.0% vs -15.2% ± 7.6%, P < .01) acetylcholine infusion was attenuated in the G-CSF group. Endothelium-independent vasodilatation after nitrate infusion did not differ between the 2 groups. CONCLUSION: Granulocyte colony-stimulating factor attenuates endothelial dysfunction after SES implantation.

Recovery of endothelial function after sirolimus-eluting stent implantation: a pilot study.

Whether endothelial dysfunction after sirolimus-eluting stent (SES) implantation is persistent has not been fully evaluated. Endothelial function was evaluated in 152 lesions that underwent follow-up coronary angiography after SES implantation. Lesions were classified into 2 groups according to the duration between SES implantation and follow-up: ≤12 months (n = 95) and >12 months (n = 57). Changes in coronary diameter in response to 10(-8) mol/L (-2.4% ± 6.3% vs -4.9% ± 3.8%, P < .01) and 10(-7) mol/L acetylcholine (Ach; -4.6% ± 7.6% vs -10.7% ± 9.1%, P < .001) in segment proximal to SES were significantly attenuated in the >12-month group than in the ≤12-month group. There were less changes in coronary diameter in response to 10(-8) mol/L (-2.3% ± 4.6% vs -6.9% ± 5.0%, P < .001) and 10(-7) mol/L Ach (-6.5% ± 11.4% vs -16.8% ± 10.5%, P < .001) in segment distal to SES in the >12-month group. Endothelial dysfunction may diminish long after SES implantation.

Incidence of side-effects of dual antiplatelet therapy with clopidogrel and aspirin after coronary stent implantation.

There is little information about the incidence of the side-effects of clopidogrel in Japanese patients undergoing coronary stent implantation. The present study included 334 consecutive patients who were given clopidogrel (75 mg daily) after coronary stent implantation. Aspirin (100 mg daily) was used indefinitely. Clopidogrel was prescribed for at least 4 weeks in patients with bare metal stents and indefinitely in those with drug-eluting stents (DES). The duration of clinical follow-up was 164.7 ± 139.0 days. Half of the patients underwent stenting because of acute myocardial infarction. DES were used in 38% of the patients. Definite early stent thrombosis occurred in one patient (0.31%). There was one definite late stent thrombosis (0.31%). Side-effects of the clopidogrel were observed in 16 patients (4.9%). Liver dysfunction occurred in seven patients (2.1%), skin rash in six (1.8%), and bleeding in three (0.9%). There was no neutropenia or thrombocytopenia. The results of this study show that prescribing clopidogrel as well as aspirin is a safe treatment for Japanese patients undergoing coronary stenting.

Long-term safety and efficacy of low-dose clopidogrel in Japanese patients undergoing coronary stenting: a preliminary study.

This study evaluated long-term safety and efficacy of low-dose (50-mg) clopidogrel in Japanese patients undergoing coronary stenting. A total of 126 patients with 153 lesions who consented to take a 50-mg maintenance dose of clopidogrel to prevent stent thrombosis were enrolled. The duration of clinical follow-up was 13.9 ± 9.7 months. There was one early stent thrombosis (0.65%). Neither late nor very late stent thrombosis was observed in patients on clopidogrel plus aspirin. Side effects of clopidogrel were observed in 9 patients (7.1%). This preliminary study shows that 50-mg maintenance dose of clopidogrel may be acceptable in Japanese patients undergoing coronary stenting.

Damage to polymer of paclitaxel-eluting stent.

The polymer of paclitaxel-eluting stents (PES) plays an important role in controlling the release of paclitaxel. Damage to the polymer of a PES that is used in a patient has not been demonstrated, although in-vitro studies report disruption of it. The present case report describes damage to a PES as delivery through a calcified coronary artery was being attempted.