To the Editor: A major problem in managing patients with hypertension (HTN) is differentiating between patients with true HTN and those with pseudohypertension (PH). Unrecognized PH may lead to unnecessary antihypertensive therapy with possible adverse effects and considerable cost. 1 Furthermore, recent literature has suggested that overtreating HTN in patients with coronary artery disease (CAD) may increase mortality. 2
Historically, William Osler attempted to identify pseudohypertension by palpating arterial elasticity; this technique has been termed Osler's maneuver. 3 Previous attempts to utilize Osler's maneuver to differentiate between HTN and PH have been largely unsuccessful because of interobserver variation. 1 , 4 Osler's maneuver is based on distinguishing between a palpable compared with a nonpalpable artery distal to sphygmomanometer cuff placement. Therefore, in HTN, an occluded downstream artery will not be palpable with an arterial radius of 0. In contrast, PH yields an artifactually high blood pressure due to a noncollapsible artery, most often due to MÖnckeberg's sclerosis, with measurable arterial radius. MÖnckeberg's sclerosis and aging increase arterial wall stiffness and change arterial wall biomechanical behavior during sphygmomanometer cuff compression. 5 , 6 Sphygmomanometer cuff pressure can be divided in 2 parts: (1) cuff pressure overcoming arterial wall stiffness; and (2) cuff pressure overcoming actual blood pressure. Consequently, spuriously high sphygmomanometer cuff pressure may be recorded when additional pressure is required to overcome increased arterial wall stiffness. Arterial wall stiffness can be represented mathematically to explain PH. The stiffness equation is as follows: Stiffness (arterial wall bending resistance) = EI, where E = Young's modulus of elasticity and I = moment of inertia of a rectangular arterial profile (I=wh3/12, where w = artery segment width, h = arterial wall thickness). This equation demonstrates that a greater wall thickness can increase the arterial bending resistance by a power of 3. In addition, MÖnckeberg's sclerosis increases the modulus of elasticity causing greater arterial stiffness as well. 6
METHODS
To increase the accuracy of Osler's maneuver, we adapted it to modern ultrasound techniques. Two‐dimensional images of the brachial artery were used to estimate wall tension in normal controls and in patients with presumed PH before and following inflation of the sphygmomanometer cuff to the point of obliteration of the brachial artery pulse. We applied a technique analogous to that used in ultrasound assessment of the lower extremities for deep venous thrombosis, whereby we applied mild pressure with the transducer on the brachial artery before and following cuff inflation and examined the vessel wall diameter.
RESULTS
Our preliminary findings, based on 5 subjects with clinically suspected diagnoses of PH, demonstrated that the brachial artery readily collapsed with minor transducer pressure after cuff placement in normotensive individuals, but the arterial wall showed a circular profile on ultrasonography in patients with clinically presumed PH. This provided a potential method to identify these patients by ultrasonographic vessel wall measurements. PH was clinically suspected in individuals who demonstrated the following: long‐standing “HTN” in elderly patients; less evidence of end‐organ damage than might be expected from review of their medical records, such as measurements of renal function (24‐hour urine protein, blood urea nitrogen, and creatinine levels), cardiac disease (transthoracic echocardiography for left ventricular thickness), and retinopathy (grade of hypertensive retinopathy utilizing photographic retinal inspection); and extreme refractoriness to antihypertensive agents, including multiagent regimens. At this point, we had no intra‐arterial pressure measurements.
COMMENTS
We are planning to expand the use of our technique with correlative invasive intra‐arterial pressure measurements and apply the technique to a broader patient group. It is possible that the ultrasonographic Osler's maneuver may prove to be a useful tool in evaluation of the hypertensive patient.—Frank Landino, MS, MPH, MSIII, Old Westbury, NY; Scott B. Berger, MD, PhD, New Haven, CT; Henry L. Kamin, MD, Valhalla, NY
References
- 1. Belmin J, Visintin JM, Salvatore R, et al. Osler's maneuver: absence of usefulness for the detection of pseudohypertension in an elderly population. Am J Med. 1995;98:42–49. [DOI] [PubMed] [Google Scholar]
- 2. Messerli FH, Mancia G, Conti C, et al. Dogma disputed: can aggressively lowering blood pressure in hypertensive patients with coronary artery disease be dangerous? Ann Intern Med. 2006;144:884–893. [DOI] [PubMed] [Google Scholar]
- 3. Messerli FH, Ventura HO, Amedeo C. Osler's maneuver and pseudohypertension. N Engl J Med. 1985;312:1548–1551. [DOI] [PubMed] [Google Scholar]
- 4. Tsapatsaris NP, Napolitana GT, Rothchild J. Osler's maneuver in an outpatient clinic setting. Arch Intern Med. 1991;151:2209–2211. [PubMed] [Google Scholar]
- 5. Foran TG, Sheahan NF. Compression of the brachial artery in vivo. Physiol Meas. 2004;25:553–564. [DOI] [PubMed] [Google Scholar]
- 6. Foran TG, Sheahan NF, Cunningham C, et al. Psuedohypertension and arterial stiffness: a review. Physiol Meas. 2004;25:R21–R33. [DOI] [PubMed] [Google Scholar]