Aortic Stenosis

In Rapid Referral Clinic this week we had a patient presenting with worsening pedal edema, our differential diagnosis including her short-course of prednisone (following an asthma exacerbation), and a possible mild exacerbation of her congestive heart failure. 

Of note in her past medical history, she also had moderate aortic stenosis, for which she was followed by a Cardiologist. 

During my focused assessment, I spent most of the time characterizing her present symptoms in relation to her heart failure, and conducting a complete volume assessment. When listening to her heart, I noted her Grade 3/6 systolic ejection murmur, loudest over the right sternal border.  Upon completion of the exam, I reviewed the case with my staff, and we returned to the clinic room to meet with the patient. My staff introduced himself and asked a few questions, and then pulled out his stethoscope, placing it gently over the patient's right clavicle. As he moved to her carotid artery, distant memories of exam maneuvers floated into my mind. I took out my own stethoscope, to listen once again over her upper sternal borders, and followed my staff in placing my hands over her brachial and radial arteries, closing my eyes and holding my breath to hone in on the subtle delay between the pulses.   

After the appointment, we sat down together to review the clinical approach to aortic stenosis, an approach I've worked through a few times in the last two years, but often have to return to to recall the specific exam maneuvers (and the significance of each). When it comes to aortic stenosis (and valve diseases generally), I feel confident in my ability to think through the pathophysiology and symptomatology of the disease (i.e. ideas about forward flow and perfusion, and back flow, remodeling, and ultimate congestion); over this past year I've worked to try and relate these processes to physical exam findings, and even more so, discern which exam findings are the most pertinent in evaluation (which has necessitated continued review on my part as a trainee). 

Etchells et al. (1998) provide a straightforward approach to evaluating suspected aortic stenosis on history and exam; for the exam, they ask a few questions:

1. Does the patient have a systolic ejection murmur that radiates to the right clavicle?

If no, chances are this patient does not have moderate-severe aortic stenosis (LR 0.1).

If yes, we look for a few other pertinent findings: 

- Is the murmur heard loudest over the right upper sternal border?
- Is the second heart sound diminished?
- Is the carotid pulse weaker than expected?
- Is the carotid upstroke delayed?

3-4 positive findings yield a likelihood ratio of 40, for a diagnosis of moderate-severe aortic stenosis.
0-2 findings = indeterminate (LR 1.76). 

In my most recent review of the clinical exam guidelines, I found it particularly helpful to understand the details of how to perform specific maneuvers; for instance, listening for murmurs over the clavicle, with practical tips on how to alter your approach for different patients (i.e. in thinner patients, using the bell instead of the diaphragm, etc.)   

I was glad to have this opportunity to review the clinical examination for aortic stenosis, and also prompt further reading on how best to follow our patients, reduce risk and prescribe appropriately given different clinical stages, and when to consider surgical management.  

-AS

Link to publication (Etchells et al. 1998): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1500900/