“There is no disease more conducive to clinical humility than aneurysm of the aorta.”   William Osler, 1849-1919

    John Ritter, star of television’s Three’s Company, died unexpectedly at age fifty-four from aortic dissection, a catastrophic event which starts as a small tear in the lining of the aorta, the largest blood vessel in the body. His tear, like most aortic dissections, occurred in the part of the aorta that exits the heart and ascends toward the head, but dissections can anywhere along the course of the aorta as it turns and then descends along the back wall of the chest and abdomen. Actor Alan Thicke’s recent death has also been attributed to an aortic tear. In neither case was the cause of death confirmed by autopsy, presumably because diagnosis was made clinically and by imaging studies once the men reached medical care. Diagnosis in both cases came too late for their lives to be saved. The first step in saving the life of someone with an aortic dissection is recognition of the symptoms. As Osler accurately stated, this is not necessarily easy. 

Upper Aortic Symptoms 
Symptoms of aortic tears vary according to the part of the aorta involved. In the upper aorta, as in Ritter’s case, the tear appears without warning. The first symptoms, such as severe chest pain, confusion, dizziness, nausea and vomiting, come from blood tunneling its way into the tear and under the aortic lining, separating it from the thick outer wall of the blood vessel. Heartbeat by heartbeat, the tunnel enlarges and a growing clot of blood extends around the inner circumference of the aorta and along its length, stretching from the ascending part of the thoracic aorta into the curved aortic arch branches where large arteries branch off and carry blood to the head and arms. 

The differences between dissection and heart attack symptoms

    Sadly, like John Ritter, almost 40 percent of people with upper aortic dissection who get to medical attention are not diagnosed in time for doctors to attempt surgical repair. Within forty-eight hours, half of them are dead. Diagnosis depends on recognition of subtle and qualitative characteristics of symptoms that differ from similar heart attack symptoms. Chest pain is severe from the beginning and sometimes described as ripping or tearing. Its most distinctive quality is sudden onset of maximally severe pain . Often people report a sense of impending doom. The pain may radiate up the neck or into the back, as it can in a heart attack. As the dissection progresses, clotting blood can block the openings to the aortic arch branches and even work its way backwards to damage the coronary arteries that nourish the heart. The aortic valve may be damaged and begin to leak. 

Symptoms From the Descending Aorta

     While the involvement of so many other structures in an upper aortic dissection can produce a host of symptoms that manifest themselves in the heart, the brain, the neck, the face, and the extremities, sometimes confusing physicians, descending aortic symptoms are more straightforward. Pain from dissection in the descending thoracic aorta bores through to the back. In the abdominal aortic segment dissection pain may be felt in the flank, lower back, or groin. Because the descending aorta is more tightly bound to surrounding structures, tears may be more confined and symptoms less severe. 

Dissections and Aneurysms

   Sometimes a dissection begins in an aortic wall already weakened enough to have ballooned out into an aneurysm, which is a distended spot in an artery wall. Ninety-five percent of aortic aneurysms are located in the abdominal aorta, and aortic dissections in the abdomen are often triggered by the prior development of an aneurysm. A tear in the wall of an aneurysm can cause the aorta to rupture completely causing internal bleeding, with mortality rates between 75 percent and 90 percent of aortic aneurysms Fortunately, aneurysms are often found incidentally on imaging tests for other problems, or as part of an investigation of vague abdominal or back pain or of a pulsating sensation in the lower abdomen allowing time for surgical repair of the damaged artery before rupture occurs. 

Who’s at Risk
    Most upper aortic dissections occur in people between the ages of forty and seventy, with men affected three times as often as women. In otherwise healthy and relatively young people like John Ritter, the tear begins because the aortic wall is weakened by genetic processes that are often poorly understood. Pregnancy and cocaine use are also risk factors below age 40. In older people and in smokers high blood pressure, atherosclerosis are responsible for the breakdown in the aortic lining, but even in these patients, dissections tend to run in families. 

     While smoking, hypertension, and atherosclerosis are risk factors in all types and locations of aortic disease, the abdominal aorta is particualry susceptible to their degenerative effects. Abdominal aortic disease is far more common than the forms of aortic disease that affect younger people and most aneurysms of the abdominal aorta reflect age-related (over age sixty) vascular degeneration. An estimated 5 percent of men over age sixty-five have some degree of degenerative abdominal aortic dilatation. 

The importance of family history
Assessment of a patient’s family history is very important in diagnosing aortic diseases like aortic dissection because genes control the proteins that make up the connective tissue of the thick aortic wall, and there can be a hereditary predisposition to dissection and aneurysm formation, particularly in younger people like John Ritter. One relatively common condition (1 in 5000 people), which can affect the connective tissue and lead to aortic dissection, is Marfan’s syndrome. The Olympic volleyball star Flo Hyman had Marfan’s syndrome, which accounted for her six feet five stature and long arms and fingers. She died at age thirty-two of aortic dissection. Dissections can also occur in people with congenital heart abnormalities, particularly those that affect the aortic valve.  

Treatment
Surgical repair of aortic aneurysms and dissections is a serious and complicated undertaking. Incidentally discovered abdominal aneurysms and aneurysms found by screening programs should be followed carefully with ultrasound or computerized tomography scans because the risk of rupture is correlated with the size of an aneurysm. Surgical repair is far less dangerous when done before dissection or rupture but carries risk enough to warrant waiting if the aneurysm is less than five centimeters in diameter. 

    Once a dissection has begun, the outcome of surgical repair rests heavily on the condition of the patient going into surgery, on the experience of the surgical team and hospital involved, and on the complexity of the procedure required. In recent years, radiologists and cardiologists have developed procedures to repair the inside of the aorta by deploying stents and grafts via catheters inserted though the arms or legs and guided by x-ray. Initially, these procedures were only used on patients who were too frail or sick to undergo the rigors of open surgery. Increasingly, though, these less invasive procedures are gaining favor and are even being used to repair dissections of the descending thoracic aorta, which have traditionally been treated by careful control of blood pressure. More research will have to be done to assess the long-term outcome of stent and graft treatments. 

Not even recent technological advances would have helped John Ritter, however, because the proper diagnosis was not made prior to his death. His family has since set up an educational foundation called the John Ritter Foundation for Aortic Health (http://johnritterfoundation.org/your-aortic-health/) with the goal of increasing knowledge and awareness about a disease which is still a very humbling clinical problem for the medical professio