Apparatus for use in coronary artery bypass surgery

The apparatus comprises a blood flow conduit 10 of T- or L-shape having a first end for insertion into and retention within a wall of a heart chamber 44 containing oxygenated blood and a second end for retention within a coronary artery 30, the conduit defining an open flow blood path during both systole and diastole. The conduit may be such as to bias forward flow of blood from the first towards the second end while not blocking reverse flow and may comprise a deflection surface for blocking flow through the conduit from impinging directly upon the coronary artery. Means may be provided in the conduit for reducing but not blocking blood flow during diastole.