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

Several recent clinical studies have suggested that proper vascular stent deployment directly affects clinical outcome, and the rate of re-stenosis. These studies suggest that angiography alone is not sufficient to ensure proper vascular stent deployment, and that re-stenosis rates will decline if proper stent apposition has occurred. The importance of proper stent sizing and apposition is further emphasised with the increasing use of drug eluting stents, the drug effects of which are only realized upon contact with the arterial wall.

Angiometrx Inc. developed the Metricath Arterial Measurement System in response to the need for increased stent sizing and deployment. The Metricath System measures the diameter and cross sectional area of arteries using an intravascular balloon catheter attached to a computerized console. Considering the ease and rapidity of obtaining Metricath results, this technique may form an alternative to evaluate vessel area and stent expansion.

The Metricath System was 510(k) cleared in the U.S. in June, 2003, and received European and Canadian market approvals in 2004.

Angiometrx Inc. has now developed the next generation of Metricath System, which incorporates a second balloon on the catheter, intended for angioplasty purposes. The Metricath Gemini System is comprised of a dual balloon catheter which is attached to the same Metricath computerized console as the Metricath System. As with the Metricath System, the Metricath Console operates the inflation and deflation of the Gemini measurement balloon and provides arterial cross-sectional area and diameter. The Metricath Gemini angioplasty balloon is controlled separately in the traditional manner using a hand-held inflation device, attached to a port in the hub of the catheter.

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°.