Translation: “世界上，治疗心脏病最好的方式就是不要开刀。”
The epitaph is probably


  "I would like to think that I've left the world of cardiovascular surgery better than when I found it. That would be a suitable epitaph." — C. Walton Lillehei, 1995.


materials


C. Walton Lillehei, the “Father of Open Heart Surgery”. This article proves Mr. Lillehei has the title "心脏病之父", and he is an American.
State of the Heart: The Practical Guide to Your Heart and Heart Surgery. This book quotes what he said as


However I cannot find that epitaph on his tombstone.



So, the statement "在他的墓碑上面，刻了..." seems not true.