Asian Paclitaxel-Eluting Stent Clinical Trial - ASPECT

Description:

The goal of the Asian Paclitaxel-Eluting Stent Clinical Trial ASPECT was to compare the safety and effectiveness of paclitaxel-eluting stents with uncoated stents of the same type.

Hypothesis:

Use of the paclitaxel-eluting stent will result in a reduction in percent stenosis at four- to six-month angiographic follow-up.

Study Design

Study Design:

Patients Enrolled: 177
Mean Follow Up: Six months
Mean Patient Age: Mean age 60 years
Female: 24

Patient Populations:

Age ≥18 years and discrete coronary lesion (<15 mm in length, 2.25 to 3.5 mm in diameter)

Exclusions:

Ejection fraction <35%; coagulopathy; intractable hypersensitivities; the performance of other studies within the previous 30 days; pregnancy; a life expectancy <1 year; MI within the previous 72 hours; other revascularization procedures within one month; the presence of coronary thrombus; severe calcification; total occlusion; another stenosis of >50% in the target vessel; a lesion length >15 mm; multiple stents; proximal tortuosity; angulation >45%; unprotected left-main coronary lesions; and poor distal runoff

Primary Endpoints:

Percentage stenosis at four- to six-month angiographic follow-up

Secondary Endpoints:

Late loss, the rate of restenosis (defined as stenosis >50%), in-stent minimal lumen diameter, incidence of death, acute and subacute thrombosis, the need for coronary bypass surgery or intervention to treat clinical ischemia due to restenosis of the target lesion, and MI due to restenosis of the target lesion

Drug/Procedures Used:

Patients underwent angiography prior to enrollment. After meeting the angiographic inclusion criteria, patients were randomized double-blind to either paclitaxel-eluting stents (3.1 µg per mm2, n=60; or 1.3 µg per mm2, n=58) or bare stents (n=59).

Concomitant Medications:

The protocol recommended aspirin and clopidogrel or ticlopidine before the procedure; heparin during the procedure; and aspirin, ticlopidine, or clopidogrel following the procedure.

Principal Findings:

The primary end point of percent diameter stenosis decreased in both the low- and high-dose paclitaxel-eluting stent arms (39% in the control group vs. 23% in the low-dose group and 14% in the high-dose group; p<0.001). Late lumen loss was also reduced in a dose-dependent manner in the eluting-stent arm (1.04 mm in controls, 0.57 mm in the low-dose group, and 0.29 mm in the high-dose group; p<0.001).

Binary restenosis occurred more frequently in the bare stent arm compared with the eluting stent arms (27% in the control arm, 12% in the low-dose arm, and 4% in the high-dose arm; p<0.001). Neointimal hyperplasia at follow-up was higher in the bare stent arm compared with the eluting stent arms (31 mm3 in the controls, 18 mm3 in the low-dose group, and 13 mm3 in the high-dose group; p<0.001) in the 81 patients in the intravascular ultrasound substudy.

Three patients in the high-dose arm had a subacute thrombosis compared with only one in the low-dose arm and none in the bare stent arm. Event-free survival at six months was 90% in the high-dose arm, 93% in the low-dose arm, and 95% in the bare stent arm.

Interpretation:

Among patients with discrete coronary lesions, treatment with paclitaxel-eluting stents was associated with a reduction in the primary end point of percent diameter stenosis at six-month angiographic follow-up compared with bare stents.

The ASPECT trial continues to add to the growing body of evidence along with the TAXUS trials that paclitaxel-eluting stents reduce restenosis and late lumen loss compared with bare stents. The eluting-stents were nonpolymeric, as with the recent DELIVER trial, which did show a reduction in late lumen loss, but did not show a significant reduction in the primary end point of target vessel failure defined as death, myocardial infarction (MI), or target lesion revascularization.

Longer follow-up is needed to determine if the restenotic process is delayed, as well as to determine the clinical implications. As with other drug-eluting stent trials, there was no difference between the drug-eluting and bare stent arms with regard to mortality or MI.

References:

Park SJ, Shim WH, Ho DS, et al. A paclitaxel-eluting stent for the prevention of coronary restenosis. N Engl J Med. 2003;348:1537-45.

Clinical Topics: Invasive Cardiovascular Angiography and Intervention, Atherosclerotic Disease (CAD/PAD), Interventions and Coronary Artery Disease

Keywords: Paclitaxel, Coronary Artery Disease, Myocardial Infarction, Follow-Up Studies, Thrombosis, Drug-Eluting Stents, Disease-Free Survival, Constriction, Pathologic, Hyperplasia


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