Rapid Rise in Cardio-Ankle Vascular Index as a Predictor of Impending Cardiovascular Events -Smooth Muscle Cell Contraction Hypothesis for Plaque Rupture

Kazuhiro Shimizu,1 Mao Takahashi,1 Shuji Sato,1 Atsuhito Saiki,1 Daiji Nagayama,1,2 Takashi Hitsumoto,3 Akira Takahara,4 Kohji Shirai1,5 1Department of Internal Medicine, Toho University Sakura Medical Center, Sakura, Chiba, Japan; 2Department of Internal Medicine, Nagayama Clinic, Oyama, Tochigi, Japan; 3Hitsumoto Medical Clinic, Shimonoseki, Yamaguchi, Japan; 4Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba, Japan; 5Department of Internal Medicine, Seijinkai Mihama Hospital, Chiba, Chiba, JapanCorrespondence: Kazuhiro Shimizu, Department of Internal Medicine, Toho University Sakura Medical Center, 561-4 Shimoshizu, Sakura, Chiba, 285-8741, Japan, Tel +81-43-462-8811, Fax +81-43-462-8820, Email k432@sakura.med.toho-u.ac.jpAbstract: Predictive factors for vascular events have not been established. The vasculature of the atheroma is supplied by penetration of the vasa vasorum through the smooth muscle cell layer from the adventitia. Smooth muscle cell contraction induces compression of the vasa vasorum, resulting in ischemia in intimal atheromatous lesions. Cardio-ankle vascular index (CAVI) has become known as an index of arterial stiffness of the arterial tree from the origin of the aorta to the ankle. CAVI reflects the progress of arteriosclerosis, and a rapid rise in CAVI indicates arterial smooth muscle cell contraction. We hypothesized that rapidly increased arterial stiffness evaluated by CAVI may be a predictor of impending cardiovascular events.Keywords: arterial stiffness, stress, plaque rupture, CAVI