Simvastatin improves arterial compliance in the lower limb but not in the aorta

Several cardiovascular risk factors adversely affect arterial compliance or the distensibility of large arteries. The role of raised low-density lipoproteins (LDL) cholesterol is uncertain, most studies having shown little effect. We, therefore, investigated whether lowering LDL would improve arterial compliance. Twenty hypercholesterolemic subjects (LDL cholesterol 4.95±1.11 mmol/l) were randomized to simvastatin (20 or 40 mg daily) or placebo, each for 4 weeks. Arterial function was assessed at the end of the placebo and simvastatin periods, systemic arterial compliance (SAC) and pulse wave velocities (PWV) centrally (aorto-femoral) and peripherally (femoral-posterior tibial). Results: Lipoproteins (LDL) cholesterol was reduced similarly with 20 and 40 mg simvastatin (ten subjects each dose) and data were pooled. Lipoproteins (LDL) cholesterol fell 39%, plasma triglyceride fell 18% and high-density lipoprotein (HDL) cholesterol rose 12%, all significant. Systemic arterial compliance (SAC) and central PWV did not change significantly but peripheral PWV showed evidence of greater compliance after simvastatin (10.1±1.3 vs. 9.4±1.3 m/s with placebo and simvastatin, P<0.03), distensibility being inversely related to PWV. Improvement in PWV was greatest in those with poorest baseline values, r=0.50; P<0.02. Conclusion: Peripheral PWV was alone improved with LDL lowering probably because of the muscularity of that arterial bed; central PWV and SAC (in the elastic aorta) were not influenced.