Minimally invasive method for creating coronary stenosis in a swine model for MRI and SPECT imaging

RATIONALE AND OBJECTIVES. To develop a less-invasive method for creating co ronary stenosis In an animal model for the study of myocardial perfusion de fects by using magnetic resonance imaging (MRI) and single-photon-emission computed tomography (SPECT). METHODS. Eleven farm pigs were instrumented with an MR-compatible coronary flow-reduction fitting in the left anterior descending coronary artery (LAD ). These fittings were turned from a nylon rod, tapered from a maximum oute r diameter of 3 mm, and drilled to a specified inner diameter (depending on the degree of coronary stenosis desired). The how-reducing fittings were d elivered over a coronary guidewire and advanced to a wedge position in the proximal LAD with an angioplasty catheter via a carotid artery approach. Pe rfusion determined by contrast-enhanced MRI at peak dipyridamole stress was compared with that obtained by Tc-99m sestamibi SPECT, Radiolabeled micros pheres were injected at rest, after stenosis implantation, and at peak phar macological stress to establish the severity of the coronary lesion. RESULTS. Coronary stenosis was successfully created in seven animals. Mild coronary stenoses (<60%) were created in four animals, Significant coronary stenoses (80%-90%) were created in three animals. Thrombosis of the corona ry flow-reducing fittings was observed in four animals, leading to sudden d eath in three animals and myocardial infarction in one animal. CONCLUSIONS. This method of angioplasty-guided, LAD coronary stenosis creat ion in a swine model presents a less-invasive alternative to open-chest tec hniques such as hydraulic occluders and ameroid constrictors.