Aortic Dissection: Warning Signs
One of the more commonly misdiagnosed cardiac conditions is an aortic dissection. An aortic dissection is a tear or partial tear in the lining of the largest blood vessel in the body, the aorta. The aorta is comprised of three layers: intima (inner-most layer), media (middle layer) and adventitia (outer layer). An aortic dissection begins with the formation of a tear in the aortic intima that directly exposes the medial layer to the pulse force of the blood. The blood then penetrates the medial layer and cleaves (propagates) the media longitudinally, thereby dissecting the aortic wall. The blood-filled space between the dissected layers of the aortic wall becomes the false lumen (channel within a tubular vessel). Eventually, the shear forces associated with the pumping blood cause the aorta/false lumen to expand to such a point that it ruptures, much like an aneurysm, causing a person to exsanguinate. Not surprisingly, therefore, hypertension (high blood pressure) is the single largest risk factor for aortic dissection given the shear forces associated with the increased rate of blood flow in the vessels.
Patients who have an acute aortic dissection have a true surgical emergency. Although it is a statistically rarer event in younger patients, aortic dissections are generally regarded as the most common acute aortic condition requiring emergent intervention. In patients who present with a sudden onset of severe chest pain, regardless of a patient’s age, the 3 potential coronary diagnoses that are imminently life threatening, and therefore must be immediately ruled out, are myocardial infarction, pulmonary embolism and aortic dissection. It is undisputed that the survival rate increases dramatically the sooner a person is treated for an aortic dissection. In fact, leading medical literature states that aortic dissection carries with it a mortality rate in excess of 1% per hour after its onset if appropriate medical management and treatment is not undertaken.
Aortic dissections are classified based on the location and extent of aortic involvement. Generally speaking, there are two types of aortic dissections: Type A (ascending) and Type B (descending). Type A dissections occur when the tear originates in the ascending aorta (coming out of the heart) and propagates either backwards toward or away from the heart into the aortic arch. Type B dissections occur when the tear originates in the aortic arch and/or the descending aorta and propagates exclusively away from the heart, downward toward the blood vessels branching off the aorta, including the renal arteries, resulting in organ dysfunction and/or organ ischemia.
The leading medical textbooks and literature are uniform when it comes to delineating the classic signs and symptoms associated with aortic dissection. By far, the most common initial symptom of acute aortic dissection is pain, which is found in up to 96% of reported cases. The pain is typically of sudden onset and is as severe at its inception as it ever becomes. In fact, the pain of aortic dissection has often been described as excruciating and/or unbearable, forcing the patient to writhe in agony, fall to the ground, or pace restlessly in an attempt to gain relief. The pain is also most often described as 10/10 by the patient. This is in contrast to the pain generally associated with myocardial infarction (heart attack) which usually has a crescendo-like onset and is not as intense. The subjective description of the pain is often eerily accurate to the actual event with most patients describing the pain with such adjectives as “sharp,” “stabbing,” “tearing,” or “ripping.”
Another important characteristic of the pain associated with aortic dissection is its tendency to migrate from its point of origin to other areas, generally tracking the path of dissection as it extends through the aorta. The presence of pain in the anterior (front) chest, neck, or throat strongly suggests the presence of an ascending (Type A) dissection. Conversely, the hallmark of a descending (Type B) dissection is pain occurring in the back or abdomen.
As noted above, a history of chronic hypertension is the most common predisposing risk factor for aortic dissection. Most patients who present with an acute aortic dissection present with severe hypertension. Importantly, severe hypertension is more predominately found in patients with a descending (Type B) dissection, occurring in 70% of cases. Yet another common symptom of aortic dissection is aortic regurgitation; i.e., when the valve between left ventricle and aorta does not close properly, resulting in blood flowing backwards through it into the heart. Aortic regurgitation occurs in up to 32% of patients.
Lastly, patients with descending aortic dissections that have compromised the blood flow to branch vessels off of the aorta may present with evidence of organ dysfunction. For example, in instances in which the dissection has propagated to the level of renal arteries, a patient may experience renal dysfunction, evidenced by a rise in creatinine and BUN laboratory values.
Based upon these classic signs and symptoms, a physician should consider aortic dissection among his/her differential and begin immediate, definitive diagnostic testing to rule in/out aortic dissection. At STSW, our lawyers have successfully resolved cases involving a failure to timely diagnose an aortic dissection. If a loved one has been the victim of a medical negligence in that an aortic dissection was negligently missed or never diagnosed, please give our lawyers at call at (410) 385-2225 for a free consultation.