Author + information
- Attila Nemes, MD, PhD* (, )
- Miklós Csanády, MD, PhD and
- Tamás Forster, MD, PhD
- ↵*2nd Department of Medicine and Cardiology Center, Medical Faculty, University of Szeged, H-6720 Szeged, P.O. Box 427, Korányi fasor 6, Hungary
We read the report by Boonyasirinant et al. (1) with great interest. The major finding of this study was that increased aortic stiffness, as indicated by increased magnetic resonance imaging (MRI)-derived pulse wave velocity (PWV), is evident in hypertrophic cardiomyopathy (HCM) patients and is more pronounced in those with myocardial fibrosis. The results are impressive, but we feel that a few additional comments are necessary.
Boonyasirinant et al. (1) used MRI-PWV analysis to quantify aortic stiffness in their clinical study. Measurement of PWV by different tonometric, piezoelectronic, oscillometric, and MRI methods are widely used scientific tools. However, there is another way to evaluate aortic stiffness, for which 2 important variables should be noted: 1) the change in volume due to blood injection into the aorta; and 2) the pressure change caused by this volume change (2). Together with measurement of forearm systolic blood pressure (SBP) and diastolic blood pressure (DBP) changes, aortic systolic diameter (SD) and diastolic diameter (DD) or cross-sectional areas at different levels of aorta can be measured with echocardiography, computed tomography, or MRI. Using these parameters, indexes or moduli can be calculated characterizing aortic elasticity (3). The most important parameters are listed here:
• Aortic strain = (SD – DD)/DD
• Aortic stiffness index (beta) = ln (SBP/DBP)/[(SD – DD)/DD], where SBP and DBP are the systolic and diastolic blood pressures, and ln is the natural logarithm
• Aortic distensibility = 2 × (SD – DD)/[(SBP – DBP) × DD]
• Aortic elastic modulus E(p) = (SBP – DBP)/[(SD – DD)/DD]
• Young's circumferential static elastic modulus E(s) = E(p) × DD/2h, where h indicates diastolic intima-media thickness
Boonyasirinant et al. (1) were the first to demonstrate alterations in aortic distensibility in HCM. However, further investigations are warranted to examine the previously mentioned parameters in HCM, especially with versus without left ventricular outflow gradients. Moreover, correlations between PWV and echocardiography-derived parameters should be confirmed in HCM as well.
- American College of Cardiology Foundation