INTRODUCTION: Repetitive, brief coronary artery occlusions produce collateral development in experimental animals. This model causes coronary collateralization in a highly reproducible fashion, but the process is very labor intensive. We report the design and use of a fully automated hydraulic coronary occlusion device capable of producing repetitive coronary occlusions and enhancement of coronary collateral development in dogs. METHODS: The device consists of analog electronics that allow adjustment of occlusion number, frequency, pressure and duration, and mechanical components responsible for the coronary occlusion. The motor and piston of the device are coupled to a chronically implanted hydraulic vascular occluder placed around the left anterior descending coronary artery (LAD) of dogs instrumented for measurement of systemic and coronary hemodynamics. One group of dogs (n = 6) underwent brief (2 min) LAD occlusions once per hour, eight times per day, 5 days/week for 3 weeks to stimulate collateral development (measured using radioactive microspheres). Another group of dogs (n = 6) that did not receive repetitive occlusions served as controls. RESULTS: The device reproducibly produced repetitive LAD occlusions for the duration, frequency, and time interval initially programmed. A time-dependent increase in transmural collateral blood flow was observed in dogs undergoing repetitive occlusions using the device. Collateral blood flow was unchanged in dogs that did not undergo occlusions. DISCUSSION: The automated occluder device reliably produces repetitive coronary occlusions and may facilitate further study of coronary collateral development in response to chronic myocardial ischemia.
INTRODUCTION: Repetitive, brief coronary artery occlusions produce collateral development in experimental animals. This model causes coronary collateralization in a highly reproducible fashion, but the process is very labor intensive. We report the design and use of a fully automated hydraulic coronary occlusion device capable of producing repetitive coronary occlusions and enhancement of coronary collateral development in dogs. METHODS: The device consists of analog electronics that allow adjustment of occlusion number, frequency, pressure and duration, and mechanical components responsible for the coronary occlusion. The motor and piston of the device are coupled to a chronically implanted hydraulic vascular occluder placed around the left anterior descending coronary artery (LAD) of dogs instrumented for measurement of systemic and coronary hemodynamics. One group of dogs (n = 6) underwent brief (2 min) LAD occlusions once per hour, eight times per day, 5 days/week for 3 weeks to stimulate collateral development (measured using radioactive microspheres). Another group of dogs (n = 6) that did not receive repetitive occlusions served as controls. RESULTS: The device reproducibly produced repetitive LAD occlusions for the duration, frequency, and time interval initially programmed. A time-dependent increase in transmural collateral blood flow was observed in dogs undergoing repetitive occlusions using the device. Collateral blood flow was unchanged in dogs that did not undergo occlusions. DISCUSSION: The automated occluder device reliably produces repetitive coronary occlusions and may facilitate further study of coronary collateral development in response to chronic myocardial ischemia.