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

To develop a less-invasive method for creating coronary stenosis in an animal model for the study of myocardial perfusion defects by using magnetic resonance imaging (MRI) and single-photon-emission computed tomography (SPECT).

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 outer diameter of 3 mm, and drilled to a specified inner diameter (depending on the degree of coronary stenosis desired). The flow-reducing fittings were delivered over a coronary guidewire and advanced to a wedge position in the proximal LAD with an angioplasty catheter via a carotid artery approach. Perfusion determined by contrast-enhanced MRI at peak dipyridamole stress was compared with that obtained by 99mTc sestamibi SPECT. Radiolabeled microspheres were injected at rest, after stenosis implantation, and at peak pharmacological stress to establish the severity of the coronary lesion.

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 coronary flow-reducing fittings was observed in four animals, leading to sudden death in three animals and myocardial infarction in one animal.

This method of angioplasty-guided, LAD coronary stenosis creation in a swine model presents a less-invasive alternative to open-chest techniques such as hydraulic occluders and ameroid constrictors.