#9 Aortic Stenosis

Before we get into this episode, just to mention, always wash your hands, always gain consent, and aim to ensure that a patient's welfare, safety and comfort is maintained throughout the exam. This podcast is supported by Past Test. Past Test is an excellent resource which has a vast library of photographs, videos and notes which you can use to help prepare for the exam. For ice-based candidates, you can also claim back the cost of the resource using the training support scheme. Hi there. Today I am with Dr. Roshan Gardner who is a cardiology specialist registrar currently working in St. Vincent's Hospital here in Dublin. Roshan, thanks so much for coming on the show. No problem, thanks for having me on. And, delighted to have you. Today we're going to be talking about aortic stenosis as a topic in the relevance of it being a short-case station in the MRCPI clinical exam. We're going to be running through some questions roughly in the structure of clinical science, investigations, management, including a differential diagnosis and then with some relevant potential follow-up questions. If that's okay with you, Roshan. Yeah, sounds good. As you said, it's a very calm station, so it's a very important one to know well. So to get started, Roshan, if you don't mind maybe talking us through some of the clinical signs that you'd expect with aortic stenosis. Yeah, of course. So to begin with, as you commence your exam at the hands and at the wrist, the first major finding would be the slow-rising pulse that's associated with aortic stenosis. And as you take the blood pressure, you would know to narrow pulse pressure. As you move on to the chest and listen to the heart sounds, of course the most important finding in aortic stenosis is the ejection systolic murmur, heard best in the aortic area and often radiating to the crotchets. And then on listening for additional sounds, you may notice an absent or a quiesh second heart sound. You may also notice the presence of a fourth heart sound S4, which is due to the forceful atrial contraction against the hypertrophied non-compliant left ventricle. Some signs that you might find that would be associated with severe aortic stenosis would be things like absent or quiesh second heart sound, mid or late peaking murmur, signs of decompensated heart failure or displacement of the apex-beast due to left ventricular hypertrophy. And Rusheen, can you talk us through the maneuvers that you might do which would accentuate a murmur of aortic stenosis? Yes, so for aortic stenosis being a left-sided murmur, this will be heard loudest on expiration. So it will be important that you demonstrate to the examiner that you're asking the patient to take a deep breath in and out and then to hold their breath. And then you'd hear the murmur loudest on expiration. If you did have a case of an ejection systolic murmur where you suspected this could be aortic stenosis. And then examine us for your differential diagnosis. What was you give? So for an ejection systolic murmur, other differentials could be aortic sclerosis where the aortic valve is calcified but not resulting in a narrow aortic valve. Another differential would be the systolic murmur associated with left ventricular outflow tract obstruction seen in hypertrophic cardiomyopathy. You could also mention that another systolic murmur, however a pan systolic murmur, could be mitro regurgitation. And how would you differentiate between aortic stenosis and aortic sclerosis? So with aortic sclerosis, there would be no radiation of the murmur to the crossheds. The pulse pressure would not be narrowed like you see with aortic stenosis. You would not have any clinical signs associated with heart failure either. Thank you, Rochene, for talking us through there realistically the most common clinical signs, but I guess it's the murmur, which is the main thing, which is you're going to be picking up on and talking about, is that fair to say in your experience? Yeah, I think the murmur is the most important thing not to miss. So it's important to take your time when listening to the heart sounds and to make sure that you move through the exam fluently and leave yourself enough time for ascultation at the end. So in such a case, if you were asked for your investigations, what would you say to the examiner? Yeah, so I think a good way for this exam when you're talking about investigations is to divide it into the bedside investigations, the blood tests, the imaging tests, and then other more invasive testing. So when it comes to bedside testing, the ECG is the most important test on an ECG for patients with the aortic stenosis. You may see evidence of left ventricular hypertrophy or conduction abnormalities. So for the blood tests, we would do the routine bloods, including a BMP. We would also pay particular attention to the hemoglobin because of the association between aortic stenosis and aides syndrome. And what is aides syndrome? Hades syndrome is a multi-system disorder where you get a triad of aortic stenosis, angiodeusplasia, causing GI bleeding, and acquired from Willabran syndrome. Hades syndrome is thought to be due to sheer stress across the narrowed aortic valve. So by far the most common cause of aortic stenosis is calcific degeneration of the valve. This is seen particularly in older patients. The prevalence of aortic stenosis is approximately 7% in patients over 75 and increases at 10% in those over 80. In younger patients with aortic stenosis, we should look out for a congenital bicuspid valves. It's also important to note the association between congenital bicuspid valves and co-rectation of the aorta. And when you're doing your clinical exam, you can check for radio-radial delay to look for a co-rectation. Another rare cause in the developed world, which more common in the developing world, is rheumatic heart disease. Ruchine, what are some of the other investigations that you would consider in a case of aortic stenosis? Because I think we've talked through the blood. So the most important investigation arguably is the echo. On echo, you'd be looking at the aortic valve, looking for is it a bicuspid or tricuspid valve, looking for calcium deposition on the valve, and then taking measurements of the valve to help classify the aortic stenosis into mild, moderate or severe. Other investigations that may be carried out are debutamine stress echoes and coronary angiograms to assess coronary anatomy prior to potential surgery. Ruchine, do you mind talking us through what would be some of the echo findings or the echo-cardiogram findings for severe aortic stenosis? So the three echo parameters to know for defining severe aortic stenosis is number one, a peak velocity of greater than four meters per second. Number two is a mean gradient of greater than 40 millimeters of mercury, and number three is a aortic valve area of less than one centimeter squared. And what would be some of the indications for further intervention? So for intervention for aortic stenosis, the first indication is severe and symptomatic aortic stenosis. A second indication would be severe asymptomatic aortic stenosis in patients who experience symptoms on exercise testing. Another indication would be severe asymptomatic aortic stenosis when the patient needs other cardiac surgery, for example, a bypass or surgery on another valve or the aorta. One last indication would be severe aortic stenosis in asymptomatic patients who have an ejection fraction of less than 50 percent without any other cause identified for this. What would be the main symptoms of aortic stenosis? So there are three main symptoms of aortic stenosis, and these are dyspnea, chest pain, and syncopy. And if a patient did require intervention, what would your options be? So the two main options are surgical aortic valve replacement or transcatheter aortic valve implantation. Otherwise known as Tavi. Do you want to tell us a bit more about who would be more suitable for a surgical valve replacement versus a Tavi? Longer patients generally less than 75 years are usually preferred for surgical. Also, patients with a low surgical risk score, for example, a uroscore to less than 4% are thought to be more suitable for surgery. Patients with a bicuspid valve or patients who are requiring other cardiac surgery, as we said, like a bypass or another valve surgery, they would be favored for surgical aortic valve replacement. And say if you were replacing someone's valve, what would be the factors you'd consider when deciding between a mechanical valve versus a biprocedetic valve? So a mechanical valve replacement is often more suitable for younger patients, so they do not need to have a repeat operation down the line. Biprovolves are also more suitable to patients who, for example, are on hemodialysis or who have hyperparathyroidism as these patients would be more susceptible to early degeneration of a bioproesthetic valve. And Rochy and Jumein, talking us through maybe your thoughts on who would be more suitable for a tavi. Tavi is usually preferred in older and more frail patients, generally over the age of 75. Tavi is also preferred in patients with a higher surgical risk score, so a euro score to of greater than 8%. It's also a good option for patients who have had previous cardiac surgery who have had a midline sternotomy before. What are some of the common complications of aortic stenosis? Some of the complications might be heart failure, pulmonary hypertension due to raised left ventricular filling pressures, conduction, abnormalities, sudden cardiac death, or infective endocardialitis due to the existing valve-wheeler elision. We've gone through some of the clinical signs as well as the potential differential diagnosis, investigations, management as well as some potential follow-up questions. Is there anything else you'd like to add, Rochy? Anything else you can think of? As we know it's a very common station and I think it's very doable. The questions are quite predictable and if you go through the questions that we've gone through here today, I think you'd be very well prepared and confident going into this station. Yeah, wouldn't be a bad one. I ended up having it as part of my station. I had a mixed aortic stenosis and my shallary agitation station, but the line of questioning went down aortic stenosis. Do you remember what you got for your, is it number two, your station two? Yeah, yours sounds like quite a tricky station. Mine was a bit more straightforward. It was a mechanical aortic valve replacement. So again, the line of questioning did go down the aortic stenosis route. So again, it was really important to be well prepared for that question. Excellent. Well, thanks so much, Rochy. I'll let you go. Thanks, Millian. Thanks for having me on. A big thank you again to Stepping on Lego, who provide our amazing show music. If you'd like to get in touch, they can be contacted at Stepping on Lego Band at gmail.com or through social media. And if you want to contact us, you can get in touch via our Instagram @mrcpi bedside, Twitter account, or ex-equent @mrcpi bedside, or email, which is [email protected]. Thanks again and good luck. luck.