What is Abdominal Aortic Aneurysm Rupture?
The rupture of an abdominal aortic aneurysm, also known as rAAA, is a serious emergency situation. If not identified and treated quickly, it can lead to severe health issues and even death, with the death rate reaching almost 100% if care is not provided. Having said that, an abdominal aortic aneurysm can be identified and fixed before it ruptures, significantly reducing the risk of death. These aneurysms can be asymptomatic until they rupture, which is a catastrophic event. Sadly, about half of the people who have aortic aneurysms experience rupture as the first sign. While it’s tough to calculate the exact death rate from ruptured aortic aneurysms, it has been reported to be as high as 90% in the past and up to 75% with current surgical techniques.
Abdominal aortic aneurysms are often found in men between 65-85 years old. The exact cause of aneurysm expansion can vary – it might be due to a severe injury or different types of infections or inflammatory diseases. Damage to the aorta, the body’s main artery, due to atherosclerosis, which is the hardening and narrowing of the arteries, has been identified as a major risk factor for abdominal aortic aneurysms. However, recently this conventional understanding has been called into question.
What Causes Abdominal Aortic Aneurysm Rupture?
Abdominal aortic aneurysms, a type of swollen blood vessel in the stomach, can burst when too much stress is put on the wall of the vessel. It’s not always easy to predict this stress because it depends on many factors like the position of the aneurysm and any blood clots inside of it.
The risk of an aneurysm bursting is closely tied to how big the aneurysm is and how quickly it’s growing. Usually, bigger aneurysms are more likely to burst, so they should be treated surgically. The best way to handle smaller aneurysms, those between 4.0 cm to 5.5 cm, is not universally agreed upon. Some studies found similar survival rates for people who got early surgery compared to those who waited until the aneurysm was larger than 5.5 cm. One study showed that there were fewer surgery complications when patients were treated early.
Rapidly growing aneurysms can also tear or burst, regardless of their initial size. Interestingly, people with a family history of aneurysms are more likely to experience a burst. The age of rupture is also lower, at 65, in these individuals, compared to 75 in those without a family history of rupture.
Risk Factors and Frequency for Abdominal Aortic Aneurysm Rupture
Abdominal aortic aneurysm (AAA) is a condition that has been decreasing in commonality over time, especially in men over 65. The rate fell from a range of 4% to 8% to just over 2% recently, typically because people quit smoking and started making healthier lifestyle choices. Most of the time, the aneurysms detected are small, less than 5.5 cm. It’s worth noting that aneurysms that grow beyond 5.5 cm have nearly a 10% chance of bursting within a year, so doctors usually recommend surgery if the aneurysm is that size or if it grows more than half a centimeter.
Between 2005 and 2012, both England and the U.S saw a decreased number of AAA cases that led to rupture, probably due to better monitoring and early intervention. The chance of rupture in the U.S was 7.29 per 100,000 people. But it’s estimated that 4% to 5% of sudden deaths are due to ruptured AAA. Only about half of the people with these ruptures even make it to the hospital, and there’s a 50% chance of dying from surgery after a rupture. However, these numbers aren’t completely conclusive.
Signs and Symptoms of Abdominal Aortic Aneurysm Rupture
An aneurysm, which is a bulge in a blood vessel, can be influenced by several risk factors. These risk factors can increase the likelihood of developing an aneurysm. They include being older, being male, having high blood pressure, having a smoking history, and having a close family member with a history of an aneurysm. After reaching the age of 50 in men and 60 in women, the chance of developing an aneurysm grows with each passing decade. Being a male or having a close family member with an aneurysm can increase the risk four times. The most significant risk factor that can be addressed is smoking, which influences not only the likelihood of developing an aneurysm but also how fast it grows.
Oftentimes, over half of patients suffering from aneurysm rupture were not aware they had an aneurysm, with as many as 30% initially given the wrong diagnosis. The classical symptoms of aneurysm rupture, such as low blood pressure, back pain, and a pulsating mass, show up in 25-50% of patients. Other symptoms like groin pain, leg pain, blood in urine, and gastrointestinal bleeding can also occur. Hence, doctors need to be very vigilant and ready to evaluate potential cases, as this is a condition that can present in many different ways.
When a person with an aneurysm arrives at the hospital, the severity of their condition can vary depending on the size of aneurysm, the place it ruptured, and how long it took them to seek treatment. If the anterior part of the aneurysm ruptures, it could result in immediate death. However, if the rupture occurs on the posterior side, it can result in less severe consequences. Smaller aneurysms leak less blood compared to bigger ones, while minor ruptures can sometimes even seal themselves, limiting the blood loss.
- Old age
- Male gender
- High blood pressure
- History of smoking
- A family history of aneurysm
- Low blood pressure
- Back pain
- A pulsating mass
- Groin pain
- Leg pain
- Blood in urine
- Gastrointestinal bleeding
Physical exam can be valuable in diagnosing an aneurysm, with the detection rate ranging from 51% to 100% for a pulsating mass. In cases of aneurysms between 3.0 cm and 3.9 cm, the detection rate is 29%, for aneurysms between 4.0 cm and 4.9 cm, it’s 50%, and for aneurysms larger than 5.0 cm, it increases to 76%. Being overweight can reduce the accuracy of detection. Rarely, some patients can show the Grey-Turner’s sign, which is bruising on the flank due to blood leaking into the layer of fat under the skin, but firmness of the lateral abdominal wall may be noticed in some cases.
Testing for Abdominal Aortic Aneurysm Rupture
If a patient is suspected of having a ruptured abdominal aortic aneurysm (rAAA), there are several important steps that should be taken. In patients who are not stable, they might need to be taken to the operating room based merely on symptoms, such as low blood pressure, flank or back pain, and a pulsating mass in the abdomen. The diagnosis can be confirmed with a bedside ultrasound.
Although there aren’t specific studies on the reliability of bedside ultrasound for rAAA, a review of available studies showed that they are incredibly accurate – they can correctly identify rAAA around 98 to 100% of the time and give false positives only about 6 to 0% of the time. These stats are similar to ultrasounds performed in radiology departments.
For patients who are in a stable condition, the best way to confirm the presence of rAAA is a CT scan conducted with intravenous (IV) contrast. This method can provide invaluable information about the location and shape of the aneurysm, as well as any potential involvement of the renal arteries.
Treatment Options for Abdominal Aortic Aneurysm Rupture
For patients who come to the emergency department with suspected rAAA, quick evaluation and action are critical. The first steps usually involve setting up two large IV lines for quick fluid and medication delivery, constant monitoring of vital signs, and blood tests to check for baseline levels of hemoglobin, kidney function, and blood clotting status. The healthcare team also needs to prepare for possible blood transfusion by matching the patient’s blood type and getting the necessary blood components like packed red blood cells, fresh frozen plasma, and platelets ready.
Studies suggest that maintaining slightly low blood pressure levels (between 80-100 mmHg) before surgery could improve patient outcomes. However, these are based on animal studies and retrospective studies, without randomized controlled trials to support this strategy. Blood transfusion is often necessary in rAAA patients. Studies have shown better outcomes when using the patient’s own blood for transfusion and maintaining balanced ratios of fresh frozen plasma and packed red blood cells in transfusion.
If rAAA is not treated, it is almost always deadly within a few hours to a week. Deciding between open surgery or a less invasive endovascular repair can be complex. This decision has to take into account factors like the patient’s age, other health issues, current vital signs, as well as factors related to the aneurysm like its location, size, and shape. The surgeon’s experience and available resources also play a role. Studies have shown lower complications and deaths with endovascular repair, but these benefits were not observed when controlling for the patient’s vital signs. A detailed review of clinical trials comparing open versus endovascular repair found neither method superior to the other.
What else can Abdominal Aortic Aneurysm Rupture be?
- Sudden inflammation of the stomach lining (Acute gastritis)
- Inflammation of the appendix (Appendicitis)
- Inflammation or infection of the diverticula in your digestive tract (Diverticulitis)
- Immediate treatment needed for pancreatic inflammation (Pancreatitis)
- Hardened deposits in gallbladder (Gallstones or Cholelithiasis)
- Blockage in the large intestine (Large bowel obstruction)
- Hearty attack (Myocardial infarction)
- Sores in the stomach lining or upper part of small intestine (Peptic ulcer disease)
- Blockage in the small intestine (Small bowel obstruction)
- Urinary tract infection or inflammation of the bladder, common in women (UTI and Cystitis)
