It has been reported that there are over 8,000 incidents a year of aortic ruptures and tears occur in car crashes. The vast majority of people who sustain this type of injury do not survive. Aortic tears/ruptures from auto accidents are the #2 cause of death at the scene of an accident — second only to head injuries — accounting for up to 15% of all deaths in auto accidents. Even though this type of injury happens quite frequently throughout the country, it is still a small percentage of all injuries from auto accidents, only about 6%. As a result, most individuals are not familiar with this type of injury and it is rarely discussed, unless it happened to you or to someone you know. Because this type of injury is usually fatal, it is important to understand what the aorta is, what can happen to it in a car crash, and what mechanisms can cause it to tear or rupture.
Anatomically, the aorta is the largest artery in the body. Blood leaves the heart through the aorta and is disbursed to the rest of the body (see diagram). The aorta rises up out of the top of the heart, bends at a certain part — called the isthmus — and then descends downward. There are smaller blood vessels at the top of the aorta that distribute blood to the brain and potentially to the upper extremities (arms, hands and shoulders). The isthmus is about 40% weaker than the rest of the aorta. As such, it is much more prone to ruptures or tearing. In fact, in certain types of crashes, 95% of people suffering aortic tears have them in the isthmus region. The top of the aorta is relatively unattached to the body, except for the vessels that distribute blood to the upper extremities and brain. Also, there is a ligament that attaches part of the aorta to the body just under the isthmus region. This area is highly susceptible to a sheering or tearing effect when put under pressure by a sudden change in velocity, such as the abrupt slowing or stopping that can occur in a car crash, which engineers call the Delta V.
The shape and bending of the thoracic aorta can cause it to act like a fulcrum or hinge point in a crash. During an auto accident, it can be placed under tremendous pressure in a very short period of time. That pressure, along with a twisting effect, can cause the aorta to rupture, especially at the isthmus. Other types of stresses can occur easily on the thoracic aorta, because part of it is free and part of it is attached to the body. This characteristic can cause a sheering effect during an auto crash, which can rupture the aorta.
Furthermore, additional and different pressures are placed on the aortic isthmus during a lateral or side crash. The pressure exerted on the thorasic aorta during a lateral or side crash is particularly damaging because a twisting effect and sheering forces often take place simultaneously. This is why approximately 95% of all aortic isthmus lacerations result from lateral or side impacts.
Aortic lacerations can occur in people of all ages. However, about 69% of all aortic lacerations that happen in auto crashes, happen to individuals under the age of 55. This group also has a much poorer chance of reaching a hospital alive after receiving this injury. Only 30% of this group reaches the hospital alive, as compared with 45% for the over 55-year-old group. However, younger individuals, once they reach a hospital, have a 50% chance of survival, while older patients have only a 20% survival rate.
If you or someone you know has suffered from an aorta rupture, laceration or tear as a result of a car crash, please call Christopher Ligori & Associates at 813-223-2929 for a free consultation.