This is the first episode in a series of short videos that cover important MLA syllabus topics with mention of the diagnostic and interventional radiology aspects of care. The MLA is a national standardised exam that will be in place next year but many medical schools are gearing up for its implementation. Therefore its syllabus is relevant to all ongoing medical school examinations.


Hi Everyone

Welcome to the first episode of our MLA Revision Series!

We hope you enjoy this episode on AAAs and look forward to posting the rest of our topics, one week at a time :)

We have also attached a summary poster with all the information included in the video.

Please consider giving us feedback as it allows us to continually update our approach in order to make content more useful

All the best,

IR Juniors Education Team

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Learning objectives

1. How AAAs present (signs and symptoms) 2. Pathophysiology 3. How AAAs are diagnosed 4. How they are treated 5. Learning summary of key points


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The following transcript was generated automatically from the content and has not been checked or corrected manually.

Everyone and welcome to this talk on abdominal aortic aneurysms, also known as AAA. This is one of the first talks in a series of MLA revision lectures which will be given for medical students by medical students. We will be covering topics in the MLA syllabus and focusing on the entirety of those topics ranging from diagnosis and presentation to prognosis and management covering the most important points. Let's start off with a case presentation. We have a 78 year old male patient who presents to ed with a three day history of persistent abdominal pain. This is a very nonspecific presentation. And so we have to keep a very open mind about what might be going on. If we can consider our differential diagnosis, we can think about our surgical s considering things that might kill the patient first and are at the top of our list and things that might be less acute and not to worry about at the moment. Let's start off with our vascular causes such as a AAA or an aortic dissection, which you would be very, very worried about. Then we can think about infection such as appendicitis or gastroenteritis. We can think about trauma such as musculoskeletal pain or even an internal bleed as a result of trauma. And then there might be a neoplasm in the abdomen which is causing this pain. But we wouldn't think of this so much in such an acute setting. We consider that a AAA was the cause of the patient's symptoms. In the previous case, we might think about how AAAS present. Otherwise the main symptom of an acute ruptured AAA is pain that is rather nonspecific in the abdomen. It can start in the umbilicus and irradiate to the back or to the flanks and doesn't really have a specific pattern. Also, the patient can present in physiological shock as a result of hypotension due to blood loss. Another rare symptom on presentation but worth considering is peripheral limb ischemia as a result of a clot embolize and occluding a distal artery that can no longer receive its blood supply. We can also detect aaa's as part of the NHS screening program which would be a bit more incidental as part of the NHS screening program. Men, over 65 years old are offered a one off ultrasound scan for AAAS depending on the results of that scan, different actions will be taken. A small AAA that is detected that is either between, that is between 3 to 4.4 centimeters will require the patient to come back for yearly scans. A medium size AAA, 4.5 to 5.4 centimeters will require three monthly scans. Whereas a large AAA which is classified as anything over 5.5 centimeters will require a two week surgery referral due to the acute risk that is posed to the patient. Let's consider the pathophysiology of AAA S and how they arise. We have a weakening of the middle layer of the arterial wall called the tunica media. And this is a gradual weakening which leads to a continual dilation of the vessel as it could no longer maintain its tension. And this leads to the lumen of the artery becoming larger and larger. If that artery ruptures as a result of it being too weak, this can be fatal and it's a very dangerous situation in which there is an 80 to 90% mortality preadmission. Another complication of AAA as mentioned before is acute limb ischemia as a result of a thrombus or embolus occluding an artery supplying a limb. Let us also consider the risk factors which allow this process to take place. If we think about our non modifiable risk factors, these relate to our cardiovascular risk factors as well and involve being a male, being of older age and having a family history of vascular events such as this one modifiable risk factors. On the other hand, include hypertension being the most important as it is, it really weakens the artery wall and smoking and COPD can, can lead to hypertension. And then we have hyperlipidemia as well as a history of other vascular events. All being major risk factors. The diagnosis, we use imaging techniques to diagnose AAA. The Gold Standard technique is an abdominal ultrasound, which is also used in the NHS screening program. As we can see on the image on the left, we have an ultrasound image of the abdominal aorta that is massively dilated and that has a thrombus in the lumen ct angiography is also used but not as widely and readily. Due to time constraints, it comes to the management of AAA S. There's two techniques that are usually used. I'll discuss the first one now, which is called open repair. Open repair is a definitive surgical treatment which involves physically suturing on the graft onto your artery to bypass the aneurysm and then suturing the artery closed. The advantages of this technique is that it is definitive. So you know that you actually have a good passageway of blood and that this the graft has been put in the correct location and there's better long term outcomes as a result of this also as a result, you don't need to do any long term surveillance because you know that everything is in the right place. However, the major disadvantages are that it is, it requires a major surgery that is very invasive and has a high perioperative mortality compared to our second technique. Nonetheless, this option is recommended in patients who are deemed able to tolerate the surgery because of how good the outcomes are in the long term. The second technique is called endovascular aneurysm repair or evar. It is a minimally invasive technique which involves going through the femoral arteries and placing a catheter in and inserting the graft which bypasses the aneurysm through the femoral artery towards the abdominal aorta. Due to the fact that it is normally invasive, we have a lower perioperative mortality and good short term outcomes. However, it is not definitive. And as a result, there are poor long term survival outcomes and higher reintervention rates. Also long term surveillance is needed because the graft may not sit in place and might require and may need to be replaced. If we think back to our case presentation at the beginning of this presentation, we might be able to see to think about how A AAA might present in a history, examination and investigation of a patient. So let's think back to our case. You end up clerking the patient in ed in the history. You find out that he has a past medical history of hypertension. Previous mi and COPD, as we mentioned, those are some of our modifiable risk factors for AAA. On examination, we have normal sort of cardiovascular examination and um respiratory abdominal except for an expand cell pulsatile abdominal mass. This is almost pathognomonic for AAA. When we think about exam questions on our investigations, we do a bedside ecg which is normal, but the BP is high further examinations we would use is our gold standard technique which is an abdominal ultrasound and that reveals a AAA. Our patient becomes more hypotensive and his pain worsens. And we would take them straight to theater as we are very worried about a rupture AAA which needs acute treatment to avoid them losing all their circulating blood volume. Having spoken about AAAS in detail from presentation, diagnosis, management, and prognosis. Let's have a quick summary slide and some of these important points that we've covered and things to take home today. Some of the MLA presentations from the syllabus that we've covered today is acute abdominal pain, cold, painful, pale, pulseless leg slash foot, which relates to acute limb ischemia and also hypertension. As we mentioned, this is a major risk factor for AAA. With regards to the pathophysiology, we discussed that it is a weakening of the arterial muscle layer which occurs over time and leads to gradual ballooning of the vessel. Risk factors for this process are being male over 65 and having a past medical history or family history of vascular or cardiovascular events. We mentioned that Triple A's are diagnosed with ultrasound scans. And this is the technique that is used in the NHS National Screening Program. Lastly, we mention that the management of A AAA is either through open surgical repair by a vascular surgeon or through evar, which is done routinely by interventional radiologists