P67 Unreliable Pulse Wave Velocity Values Provided by Algorithm-Based Device: A Study in Marfan Syndrome

Abstract

Objective

To evaluate the reliability of algorithm-based aortic pulse wave velocity (PWV) estimated by the Mobil-O-Graph (IEM, Germany) compared to a standard non-invasive measurement of aortic PWV (carotid-femoral PWV), in a population of patients with a genetic disorder causing premature stiffening of the arterial wall: Marfan syndrome.Methods:In this study, 107 patients with confirmed Marfan syndrome were enrolled (mean age 37.7 ± 15.1 years, males 50.4%, blood pressure 117.8 ± 13.6/ 69.0 ± 8.8 mmHg). PWV estimated by Mobil-O-Graph (which uses an algorithm based mainly on age and pressure acquired by oscillometric method) was compared with carotid-femoral PWV measured by PulsePen tonometer (DiaTecne, Italy). For each method, two measurements were performed simultaneously, in a single session.

Results

Mean values of PWV (±SD) of Marfan patients were 6.1 ± 1.3 m/s by Mobil-O-Graph and 8.8 ± 3.1 m/s by carotid-femoral PWV, with a weak correlation between the two (r = 0.34). The average underestimation by the Mobil-O-Graph was −2.7 ± 5.7 m/s. The values provided by Mobil-O-Graph may be derived in this population from the age square and the brachial systolic pressure (r2 = 0.98) according to the formula:PWV = age2/1000 + 0.038 * systolic blood pressure.

Conclusions

The Mobil-O-Graph provides PWV values of an ideal subject for a given age and pressure, but may not be able to evaluate the cardiovascular risk expressed by aortic PWV in patients with specific alterations of aortic wall properties, as demonstrated in this population with Marfan syndrome. The use of algorithms for the evaluation of PWV should therefore be discouraged in special populations at high cardiovascular risk.