Motivation: If you listen closely enough, you will hear a murmur. That has been my feeling about listening to murmurs over the aortic valve. Almost everyone has a "soft ejection murmur." The question, of course, is how tight is the aortic valve. We have all heard cautionary tales about the lack of correlation of murmur intensity with aortic valve area. During morning rounds, an attending suggested using the physical exam sign of "brachioradial delay" as a measure of severity of aortic stenosis. How good is the sign?
For background, brachioradial delay is assessed by gently palpating the brachial and radial pulses simultaneously. If there is a palpable delay between the brachial and radial pulses, then "brachioradial delay" is present. From a pathophysiology viewpoint, the quicker the upstroke of the arterial pulse the quicker the pulse pressure wavefront spreads through the arterial tree. In aortic stenosis, the upstroke of the arterial pulse is slower allowing some of the energy to be absorbed by circumferential stretch of the arteries. Consequently, with a slow upstroke, there is a palpable delay in the spread of the pulse upstroke between proximal and distal arteries.
Paper: Leach, R.M. and McBrien, D.J. "Brachioradial delay: a new clinical indicator of the severity of aortic stenosis." Lancet (1990); 335: 1199-201.
Methods: Patients presenting at echocardiography clinic at Worthington Hospital (U.K.) were prospectively assessed by four clinicians about the presence of brachioradial delay. Subjects were not preselected by any diagnosis. The sign was counted positive if all four clinicians agreed. Subsequently, for all the patients, the delay between the brachial and radial pulses was timed, and echocardiography was done in all patients. In the paper, severe aortic stenosis was defined as aortic valve area of 0.5-0.75 sqcm.
Results:
Patient selection: Among the patients assessed, there were 33 patients with aortic stenosis and 25 patients with other heart diseases (9 heart failure, 4 MR, 3 post MI, 3 HOCM, 2 aortic regurg, 2 afib, 1 bicuspid aortic valve, 1 heart transplant). Of the 33 patients with aortic stenosis, 17 had severe aortic stenosis (valve area between 0.5-0.75 sqcm). The authors also reported on 27 controls without heart disease who were age and sex matched.
Control Subjects: For none of the 27 control subjects was a brachioradial delay palpable. On measurement by pressure transducers, the mean brachioradial delay was 24.3 msec below age 55 and 21.7 msec for those over age 75. None of these delays were palpable.
Aortic Stenosis: In the 17 patients with "severe" aortic stenosis (valve area 0.5-0.75 sqcm), the brachioradial delay was palpable in all patients. For 16 patients with mild aortic stenosis (valve area > 0.75 sqcm), brachioradial delay was palpable in only 6 out of 16 patients.
Other Heart Conditions: In 25 patients with other heart conditions, brachioradial delay was palpable in one patient with hypertrophic obstructive cardiomyopathy. In no other patient was brachioradial delay palpable.
Discussion: This paper is remarkable in many ways. I was surprised to see a novel physical exam sign for aortic stenosis described in the relatively recent past (1990). Also surprising is the 100% sensitivity of this sign for aortic stenosis with valve area <0.75 sqcm. The physical exam sign is also good because to determine a positive sign, you do not need to have many years of experience examining normal subjects. The sign is a relative palpable delay between brachial and radial arteries. Of note, the sensitivity of the sign falls off rapidly as the valve area increases above 0.75 sqcm (only 6/16 positive).
The paper, however, also has many weaknesses. First of all, there are relatively few subjects examined. Secondly, the specificity of the sign is very poorly established. The group with "other" heart diseases was heterogeneous with few representatives of each type of cardiac pathology. Finally, of note, what is called "severe" aortic stenosis (valve area <0.75 sqcm) would likely be termed critical aortic stenosis now (at least in the U.S.) while the mild aortic stenosis in the paper would be severe aortic stenosis at present (valve area 0.75 to 1 sqcm). Despite these weakness, I think that the brachioradial delay is a good test to assess for critical AS in a patient with classic AS murmur.
For background, brachioradial delay is assessed by gently palpating the brachial and radial pulses simultaneously. If there is a palpable delay between the brachial and radial pulses, then "brachioradial delay" is present. From a pathophysiology viewpoint, the quicker the upstroke of the arterial pulse the quicker the pulse pressure wavefront spreads through the arterial tree. In aortic stenosis, the upstroke of the arterial pulse is slower allowing some of the energy to be absorbed by circumferential stretch of the arteries. Consequently, with a slow upstroke, there is a palpable delay in the spread of the pulse upstroke between proximal and distal arteries.
Paper: Leach, R.M. and McBrien, D.J. "Brachioradial delay: a new clinical indicator of the severity of aortic stenosis." Lancet (1990); 335: 1199-201.
Methods: Patients presenting at echocardiography clinic at Worthington Hospital (U.K.) were prospectively assessed by four clinicians about the presence of brachioradial delay. Subjects were not preselected by any diagnosis. The sign was counted positive if all four clinicians agreed. Subsequently, for all the patients, the delay between the brachial and radial pulses was timed, and echocardiography was done in all patients. In the paper, severe aortic stenosis was defined as aortic valve area of 0.5-0.75 sqcm.
Results:
Patient selection: Among the patients assessed, there were 33 patients with aortic stenosis and 25 patients with other heart diseases (9 heart failure, 4 MR, 3 post MI, 3 HOCM, 2 aortic regurg, 2 afib, 1 bicuspid aortic valve, 1 heart transplant). Of the 33 patients with aortic stenosis, 17 had severe aortic stenosis (valve area between 0.5-0.75 sqcm). The authors also reported on 27 controls without heart disease who were age and sex matched.
Control Subjects: For none of the 27 control subjects was a brachioradial delay palpable. On measurement by pressure transducers, the mean brachioradial delay was 24.3 msec below age 55 and 21.7 msec for those over age 75. None of these delays were palpable.
Aortic Stenosis: In the 17 patients with "severe" aortic stenosis (valve area 0.5-0.75 sqcm), the brachioradial delay was palpable in all patients. For 16 patients with mild aortic stenosis (valve area > 0.75 sqcm), brachioradial delay was palpable in only 6 out of 16 patients.
Other Heart Conditions: In 25 patients with other heart conditions, brachioradial delay was palpable in one patient with hypertrophic obstructive cardiomyopathy. In no other patient was brachioradial delay palpable.
Discussion: This paper is remarkable in many ways. I was surprised to see a novel physical exam sign for aortic stenosis described in the relatively recent past (1990). Also surprising is the 100% sensitivity of this sign for aortic stenosis with valve area <0.75 sqcm. The physical exam sign is also good because to determine a positive sign, you do not need to have many years of experience examining normal subjects. The sign is a relative palpable delay between brachial and radial arteries. Of note, the sensitivity of the sign falls off rapidly as the valve area increases above 0.75 sqcm (only 6/16 positive).
The paper, however, also has many weaknesses. First of all, there are relatively few subjects examined. Secondly, the specificity of the sign is very poorly established. The group with "other" heart diseases was heterogeneous with few representatives of each type of cardiac pathology. Finally, of note, what is called "severe" aortic stenosis (valve area <0.75 sqcm) would likely be termed critical aortic stenosis now (at least in the U.S.) while the mild aortic stenosis in the paper would be severe aortic stenosis at present (valve area 0.75 to 1 sqcm). Despite these weakness, I think that the brachioradial delay is a good test to assess for critical AS in a patient with classic AS murmur.
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