minimally invasive techniques utilized in bypass grafting are disclosed . for instance , a method of implanting an end portion of a graft in the body of a patient during a bypass grafting procedure includes the steps of advancing a medical instrument within a circulatory system of said body , guiding a distal end of said medical instrument out of said circulatory system through an opening defined in said circulatory system after said medical instrument advancing step , advancing said end portion of said graft within said medical instrument after said guiding step , and securing said end portion of said graft to a blood vessel of said circulatory system after said end portion advancing step .