Evaluation of the Metricath Gemini System, a Device Intended to Make Arterial Measurements and Perform Angioplasty Dilations.

Inclusion Criteria: * Patients in whom coronary artery angiography is indicated and angioplasty and stenting is being considered. * Single vessel disease of an artery with a lesion assessable to standard coronary guidewires and are scheduled or indicated for percutaneous coronary intervention. * A maximum of one lesion requiring treatment (angioplasty +/- stenting) to an intended arterial diameter of 2.5 mm - 4.0 mm. * Target stent length of 15 mm - 32 mm, where a single stent can adequately cover the lesion. * Stenotic de novo lesions in native coronary arteries. Exclusion Criteria: * Women who are pregnant. * Participation in a study involving investigational drugs or devices during the last six months. * Patients with previous stenting in the target vessel area. * Patients who experienced a myocardial infarction, Braunwald Class C, and very unstable Braunwald Class B3 within 6 weeks prior to the procedure or have unstable angina pectoris. * Patients who are experiencing TIA's or minor or major strokes within six months prior to procedure. * Contraindicated for antiplatelet and/or anticoagulation medications. * Symptoms of cardiogenic shock. * Patients who underwent a staged procedure 30 days prior to enrolment and/or were scheduled to have a staged procedure 14 days after treatment. * Significant liver or kidney disease or malignancy. * Patients scheduled for any other surgery or other procedure within 30 days. * Severe peripheral vascular disease preventing femoral access. * Left ventricle ejection fraction of \< 35%. * Total occlusion of target vessel. * A blood pressure in excess of 180 mmHg at the time of the angiography. * Visible thrombus, filling defect, or ulceration in the target artery. * Severely calcified lesions which suggest that balloon pre-dilatation will not achieve adequate luminal diameter to allow successful stent delivery and deployment. * The target lesion is beyond a left main artery stenosis \> 50%. * Contraindicated for CABG. * Coronary spasm in the absence of a significant stenosis. * Requiring treatment of more than two lesions. * Requiring treatment with atherectomy. * Lesions in surgical conduits - saphenous vein grafts, internal mammary arteries, or radial arteries. * Unprotected left main coronary artery. * Diffuse disease. * Excessive tortuosity of proximal segment. * Extremely angulated segments \> 90°.