Coronary artery dissection: a fatal complication following blunt chest trauma

Abstract

A 21-year-old male driver of a Suzuki motorcycle going at low speed (speed upon impact 40 km/h) grazed the wire fencing of a house tangentially. He then went off the road, hit a small tree, drove into a stream bed, and ended up lying on its bank. When the ambulance arrived at the scene of the accident, the rider had no obvious signs of injury, but was somnolent. His blood pressure was 85/50 mmHg, his pulse was 50 beats per minute, his respiratory rate was 16 per minute, and his oxygen saturation was 75 %. The man was intubated immediately. With pharmacological support of noradrenalin, the patient was transported to hospital by air. Chest and abdomen ultrasounds ruled out any internal injuries. The heart ultrasound showed left ventricular hypokinesis. An initial ECG showed ST elevation for the anterior leads. Shortly after hospitalization the man went into cardiac arrest. Despite 40 min of continuous CPR with repeated defibrillation, the heart could not be restarted and the patient was pronounced dead. The time between the accident and death was 2 h. An autopsy was performed 8 h after his death. The deceased male was 175 cm tall and weighed 81 kg. On external examination, abrasions of the skin at the knees and the lower limbs were found and a contused lacerated wound extending into the dermis was found above the inner ankle of the right foot, surrounded by bruising. Internal examination revealed swelling of the brain, soft tissue contusion of the anterior thoracic wall, thoracic bone fracture, a fracture of the 2nd and 3rd ribs in the midclavicular line on the left, contusion of both lungs, and a shallow lacerated wound at the lower pole of the spleen. Cardiac autopsy showed traumatic dissection of the left main and the proximal left anterior descending coronary artery with complete obstruction of their lumen in a total length of 4 cm (Figs. 1, 2). Macroscopically, the cardiac muscle did not show any changes. There were only small hemorrhages underneath the endocardium of both cardiac atria. Histological examination of the heart confirmed interstitial swelling in the area of anterior and anteroseptal part of the left ventricle. In this area, stretching and ruffling of a group of muscle fibers was found as one of the first signs of ischemia of the cardiac muscle (Fig. 3a, b). Nevertheless, cardiomyocyte necrosis or leukocyte infiltration of the cardiac muscle was not found. The cardiac muscle architecture was normal. Histological examination of the coronary arteries in the range of the common trunk of the left coronary artery and in the initial section of the descending segment of the left coronary artery demonstrated traumatic dissection (level 4/5–5/5 tunica media) with evident external compression of the artery lumen with intramural hematoma (Fig. 3c, d). The walls of the coronary arteries, including their elastic lamellae, were of normal structure. There were no signs of mural (medial or adventitial) or periadventitial M. Dobias Faculty of Medicine and University Hospital in Olomouc, Institute of Forensic Medicine and Medical Law, Palacky University in Olomouc, I. P. Pavlova 6, Olomouc, Czech Republic