Abstract: In a method for substantially isolating cardiac circulation from systemic circulation, flow between the coronary sinus and the right atrium is occluded. A venous collection device having a collection lumen and a support structure is located in the coronary sinus. The support structure is used to maintain patency of the coronary sinus during collection of fluid through the collection lumen. An artificial flow path is provided between the collection lumen and the one or more coronary arteries, thus isolating the cardiac circulation. According to the method, cardiac pumping for systemic circulation can be maintained during isolation of the cardiac circulation.

Abstract: A method for treating an occlusion in a coronary artery of a patient includes percutaneously advancing an occlusion treatment tool (such as an angioplasty balloon or stent delivery device) through the vasculature of the patient and into a coronary artery to a site of the occlusion. Following the treatment of the occlusion, a therapeutic agent is admitted into the first coronary artery. The therapeutic agent is selected to treat microvasculature obstructions at a target cardiac tissue site distal to the site of the occlusion.

Abstract: A method for delivering a polynucleotide to cardiac tissue, including substantially isolating the coronary venous circulation from systemic circulation, and introducing a polynucleotide into the isolated coronary venous circulation to effect localized transfection of cardiac tissue. The polynucleotide advantageously produces a therapeutic effect, such as increasing or decreasing the expression level of a protein in the cardiac tissue.