cardiac surgery training in the united states is combined with general thoracic surgery and called cardiothoracic surgery or thoracic surgery. a cardiothoracic surgeon in the u.s. is a physician (d.o. or m.d.) who first completes a general surgery residency (typically 5–7 years), followed by a cardiothoracic surgery fellowship (typically 2–3 years). the cardiothoracic surgery fellowship typically spans two or three years, but certification is based on the number of surgeries performed as the operating surgeon, not the time spent in the program, in addition to passing rigorous board certification tests. recently, however, options for an integrated 6-year cardiothoracic residency (in place of the general surgery residency plus cardiothoracic residency) have been established at many programs (over 20). applicants match into these i-6 programs directly out of medical school, and the application process has been extremely competitive for these positions as there were approximately 160 applicants for 10 spots in the u.s. in 2010. as of may 2013, there are now 20 approved programs, which include the following: