Aortic dissection is a severe medical emergency requiring immediate attention. This life-threatening condition arises suddenly. Recognizing its signs quickly and seeking prompt medical care are crucial for survival and improving outcomes.
Understanding Aortic Dissection
An aortic dissection occurs when there is a tear in the innermost lining of the aorta, which is the body’s largest artery carrying oxygen-rich blood from the heart to the rest of the body. This tear allows blood to surge through the damaged lining, splitting the layers of the aortic wall apart. As a result, a new, false channel forms within the aortic wall alongside the normal blood pathway.
This process can compromise the normal flow of blood, potentially reducing or stopping it to various parts of the body. The aorta extends from the heart, arches through the chest, and then descends through the chest and abdomen. A dissection can occur in any part of this large vessel, affecting blood supply to organs and limbs.
The Blood Pressure Discrepancy Between Arms
A noticeable difference in blood pressure readings between the two arms is a significant indicator of an aortic dissection. Specifically, a systolic blood pressure difference of 20 mmHg or more between the arms is a concerning sign. This discrepancy means that one arm will show a higher blood pressure reading compared to the other. In some cases, a pulse might even be diminished or entirely absent in one arm.
This observation is an important diagnostic clue, though it does not occur in every case of aortic dissection. When present, it strongly suggests a disruption in blood flow to one of the upper extremities. Measuring blood pressure in both arms is therefore a standard part of assessing a patient with suspected aortic dissection.
Why Blood Pressure Differs
The difference in blood pressure between arms in aortic dissection stems from the mechanical obstruction of blood flow. When the tear in the aorta extends, the false channel created by the dissection can expand. This expansion can compress or directly block the origin of arteries that branch off the aorta to supply the arms, such as the subclavian arteries.
If the subclavian artery leading to one arm is affected, the blood flow to that arm will be reduced. This diminished flow results in a lower blood pressure reading in the affected arm. Meanwhile, the other arm, whose blood supply remains unobstructed, will maintain a normal or relatively higher blood pressure. The “higher” blood pressure is typically the true systemic pressure, while the lower reading in the affected arm is a consequence of the obstruction. This phenomenon is termed pseudohypotension in the limb with the compromised artery.
Immediate Medical Attention is Crucial
Aortic dissection requires immediate medical care. If an individual experiences sudden, severe chest or back pain, often described as a tearing or ripping sensation, urgent evaluation is warranted. Other accompanying symptoms might include dizziness, shortness of breath, or a noticeable difference in arm blood pressure.
Delay in seeking treatment can lead to severe complications, including organ damage or aortic rupture. Call emergency services, such as 911, without delay if these symptoms arise. Prompt diagnosis and intervention can significantly improve outcomes for individuals experiencing an aortic dissection.