Aortic Stenosis
1) Quiz Link
It is true that agreement on murmurs has been found sub-optimal (i.e. κ = 0.19 for if a systolic murmur is even present; κ = 0.59 if a systolic murmur is > 2/6 for non-cardiologists [1, 2, 3]) and a concerning murmur is likely lead to an echocardiogram, regardless of its defining characteristics, Yet there is still utility in understanding murmur characteristics unique to varying pathology or structural changes.
Triad
The classic triad of AS is angina, dyspnea and exertional syncope. In reality, angina and dyspnea in a patient with a systolic murmur do not help much in ruling AS in or out. Extertional syncope on the other hand does suggest AS when present with +LR 3.1 but is not helpful if absent.
Table 1. Clinical Findings to Detect AS
(if a systolic murmur is present, adapted from [3])
| Finding in pts with systolic murmurs | LR+ | LR- |
| Exertional syncope | 3.1** | 0.9 |
| Angina | 0.9 | 1.3 |
| Dyspnea | 1.4 | 0.8 |
**The JAMA Rational Exam article on systolic murmurs [4] cited an article with a LR+ of ∞ with 95% CI (1.3-∞). Those authors rated the study grade C so we do not include it here.
Diagnosing AS with Exam
The classic murmur of aortic stenosis (AS) is “diamond shaped”, heard best at the right upper sternal boarder (2nd right intercostal space) and radiates to the right clavicle and right carotid. This characteristic AS murmur, if present has an LR+ of 5.9 and if absent LR- 0.1 [3].
In practice, the AS murmur can radiate widely in a “broad apical-base pattern” [3, 5]: all along the precordium, to the apex (a pattern described as a shash over the R shoulder), and can be heard above the sternum and in both carotids, especially if severe [4]. The AS murmur has also been described to sound like “clearing the throat” [5]. Such a pattern is highly suggestive of AS with a LR of 9.7.
Contrast AS with the MR murmur which is broad apical, a pattern that, if present, lowers the likelihood of AS with an LR of 0.2.
The best finding, however, may be an inaudible S2, which has a LR of 12.7!
Table 2. Clinical Findings to Diagnose AS
(i.e. AV peak velocity ≥ 2.5 m/s, adapted from [3])
| Clinical Finding | LR+ |
| Characteristic AS murmur | 5.9 (LR- 0.1) |
| Murmur pattern: – Broad apical-base – Broad apical | 9.7 0.2 |
| S2 Inaudible | 12.7 |
| Radiation to neck | 2.4 |
A delayed carotid upstroke is somewhat to very helpful in AS assessment, depending on the source [3, 4]. This exam maneuver we fear is a lost art. We commend those who can still regularly and accurately differentiate the normal rate or ‘sharp tap’ compared the a ‘nudge’ or ‘push’ of a delayed upstroke. But as we think it is not in general practice or an easily obtained skill, we do not include it here.
Assessing AS severity with Exam
Determining if a murmur is an AS murmur clinically is perhaps more straightforward than assessing if that murmur represents severe AS.
Observations that argue against severe AS are: a blowing quality murmur, with LR+ 0.1, or a murmur that does not radiate to the neck, with LR- 0.1,
Findings suggestive of severe AS include an absent or diminished S2 (LR+ 3.8, LR- 0.4), especially at the upper left sternal border, and a sustained apical impulse (LR+4.1, LR- 0.3) – an abnormal outward movement starting at S1 and extending to or past S2.
Table 2. Clinical Findings of Severe AS (adapted from [3])
| Clinical Finding | LR+ | LR- |
| Absent / Diminished S2 | 3.8 | 0.4 |
| Radiation to neck | 1.4 | 0.1 |
| Blowing quality | 0.1 | 1.4 |
| Loudest @ RUSB | 1.8 | 0.6 |
| Sustained apical impulse | 4.1 | 0.3 |
But don’t forget, the intensity of aortic stenosis depends on cycle length: the longer previous diastole (e.g., after a premature beat or pause), the louder the murmur.
Echo Assessment of AS severity
Recall that AS severity is assessed with ultrasound based on the following from AHA/ACC guidelines [7]:
| Aortic Sclerosis | Mild | Moderate | Severe | |
| Aortic jet velocity (m/s) | ≤2.5 m/s | 2.6-2.9 | 3-4 | >4 |
| Mean gradient (mmHg) | – | <20* | 20-40* | >40* |
| AVA (cm2) | – | >1.5 | 1-1.5 | <1 |
| Indexed AVA (cm2/m2) | >0.85 | 0.6-0.85 | <0.6 | |
| Velocity ratio | >0.5 | 0.25-0.5 | <0.25 |
*AHA/ACC recommendations, ESC values differ with <30, 30-50, >50 mmHg replacing above mean gradients for mild, mod, severe AS, respectively.
But this can be done at the point of care (see video below) and intervention is symptom, not purely severity based!
- E Etchells, et al. A bedside clinical prediction rule for detecting moderate or severe aortic stenosis. J Gen Intern Med. 1998 Oct;13(10):699-704.
- S Reichlin, et al. Initial clinical evaluation of cardiac systolic murmurs in the ED by noncardiologists. Am J Emerg Med. 2004 Mar;22(2):71-5.
- Stephen McGee’s Evidenced Based Physical Diagnosis, 4th ed, Elsevier, Philadelphia, PA, 2018.
- Etchells E, Bell C, Robb K. Does this patient have an abnormal systolic murmur? JAMA. 1997 Feb 19;277(7):564-71.
- McGee S. Etiology and diagnosis of systolic murmurs in adults. Am J Med. 2010 Oct;123(10):913-921.e1
- W. Proctor Harvey. Clinical Heart Disease, 1st Ed., Laennec, Fairfield, NJ. 2009.
- H Baumgartner, et al. Echocardiographic assessment of valve stenosis: EAE/ASE recommendations for clinical practice. J Am Soc Echocardiogr. 2009 Jan;22(1):1-23.
