Pressure-controlled intermittent coronary sinus occlusion (PICSO)

Pressure-controlled Intermittent Coronary Sinus Occlusion (also known as PICSO), is a procedure utilized to enhance restoration of blood flow to the microcirculation in heart tissue following a myocardial infarction.[1] PICSO has a dual therapeutic potential first for myocardial salvage and second for tissue regeneration. In a meta-analysis of preclinical studies a significant reduction of infarct size of about 30% as compared to controls was observed. Pilot clinical studies of PICSO in acute myocardial infarction confirmed an event free survival of patients indicating a significant risk reduction for reinfarction.
Conventional treatment
Myocardial infarction (MI), or heart attack, occurs when a blood clot forms around a plaque already obstructing flow in coronary arteries preventing proper blood supply.[2] Total occlusion of a coronary artery is the consequence of a plaque rupture and forming a blood clot disrupting blood flow. This leads to a risk zone with rapid loss of oxygen delivery, deprivation of nutritive flow to the heart leading to necrosis of the myocardium known as MI.[2] Myocardial infarctions are graded according to severity: The less severe type is Non ST-segment Elevated Myocardial infarction (NSTEMI) with deprivation of flow occurring only in the subendocardium. ST-Segment Elevation Myocardial Infarction (STEMI) is the severe type. 
The origin of coronary sinus intervention
The coronary sinus collects about 70% of the myocardial outflow. There are early concepts using the coronary sinus to access ischemic myocardium. First clinically useful techniques go back to the 1940s.[5] In early experimental studies the consequences of elevated pressure in cardiac veins have been analyzed. The Beck´s procedure was an operation in patients with severe coronary artery disease long before modern cardiac surgery could be performed.