Age-associated changes in regional aortic pulse wave velocity

OBJECTIVES This study was designed to determine noninvasively the age-assoc iated changes in regional mechanical properties in normals using phase-cont rast magnetic resonance imaging (PC-MIR). BACKGROUND It has been well documented that there is a progressive increase in aortic pulse wave velocity (PWV) with age. Previously, PWV has been mea sured at a single aortic location, or has compared arterial waves between c arotid and femoral points to determine PWV. METHODS Applanation tonometry (TONO) and in-plane PCMR was performed in 24 volunteers (12 men) ranging in age from 21 to 72 years old. The PCMRI PWV w as measured in three aortic segments. As validation, TONO was performed to determine PWV between the carotid and femoral artery. RESULTS When PCMRI PWV was averaged over the three locations, it was not di fferent from TONO (7.9 +/- 2.3 vs. 7.6 +/- 2.4 m/s, respectively). When the volunteers were divided into groups of < 55 and greater than or equal to 5 5 years old, the younger group showed similar PWV at each aortic location. However, the older group displayed significantly increased PWV in the regio n spanning the ascending and proximal descending aorta compared with the mi d-thoracic or abdominal segments (10.6 +/- 2.5 m/s, 9.2 +/- 2.8 m/s, and 7. 1 +/- 1.7 m/s, respectively, p < 0.001, analysis of variance). CONCLUSIONS In-plane PCMRI permits determination of PWV in multiple aortic locations in a single acquisition. Progressive fragmentation of elastic fib ers and alterations in the regulation of vascular tone may result in an age -related, regional increase in PWV primarily affecting the proximal aorta. (C) 2001 by the American College of Cardiology.