Preliminary clinical experience with the pullback atherectomy catheter andthe study of proliferation in coronary plaques

BACKGROUND: Clues to the biology of coronary artery disease can be obtained through the study of proliferation in human coronary artery plaques. Previ ously, immunocytochemistry has been used to detect the proliferating cell n uclear antigen to demonstrate low levels of proliferation in directional co ronary atherectomy tissue fragments resected from human coronary arteries. OBJECTIVES: To describe the proliferative profile of coronary artery tissue by using a more sensitive marker for cell replication. PATIENTS AND METHODS: Ten patients with unstable or stable angina pectoris underwent coronary atherectomy with a newer coronary atherectomy device, th e Arrow-Fischell pullback atherectomy catheter. The histological features o f the specimens were studied by using light microscopy, and cell proliferat ion was assessed with the use of in situ hybridization for the S phase-spec ific mRNA species, histone H3. RESULTS: Pullback coronary atherectomy immediately followed by percutaneous transluminal coronary angioplasty resulted in angiographic improvement in the lumen diameter in all but one patient, who required insertion of a sten t. The atherectomy specimens consisted of a combination of atheromatous pla que and media. Four specimens had a small amount of adventitia. Five of the 10 specimens had no proliferating cells. Three specimens had between one a nd five proliferating cells per slide, while two specimens had relatively h igh proliferation indexes (2.5% and 4.2% of all cells per atherectomy cross -section). Both smooth muscle cells and macrophages were identified in area s with proliferating cells. The histology and proliferation profiles of the tissue resected from patients with stable and unstable angina were similar . CONCLUSIONS: Pullback atherectomy can be used effectively to debulk coronar y artery lesions. By using a sensitive marker for cell replication, it was determined that the majority of the tissue specimens have low proliferation indexes.