AbstractBackgroundPenetrating thoracic trauma with coronary artery transection is a lethal injury, but is rare. We report a case of a cardiac stab wound with coronary artery transection that was successfully treated after preoperative diagnosis.Case PresentationA 36‐year‐old man was transferred to our emergency department with a left chest stab wound. A coronary computed tomography‐angiography scan, including coronary angiography, revealed left hemopneumothorax and left anterior descending branch transection, with ischemic changes in the left ventricular myocardium. Given the diagnosis of coronary artery transection and the absence of injury to the surrounding arteries, we were able to perform coronary artery bypass surgery using the left internal thoracic artery. The patient's postoperative course was good, and he was discharged on foot without major complications 18 days after surgery.ConclusionUnless a resuscitative thoracotomy is required, a preoperative computed tomography scan, including coronary angiography, may be useful for accurate preoperative diagnosis for patients at high risk of myocardial or coronary artery injury.