Normal IMT progression is approximately 0.01mm annually. There was no statistical difference between the Simvastatin (Zocor) arm and the Simvastatin/Ezetimibe (Vytorin) arm in IMT values at the end of the two year trial. There were no safety concerns revealed in the study regarding treatment with the two drugs. The population selected for the study included a very unique heterozygous familial hyperlipidemia group that had baseline LDL levels > 316mg/dL. This is a rare condition that affects approximately 0.2percent of the overall population and encompasses a very difficult lipid issue. As we know, the complexity of lipid abnormalities goes beyond an isolated LDL problem. Statin therapy has pleotrophic benefits that go beyond LDL reduction, including reducing intimal inflammation and endothelial inflammation, decreased WBC adherence to the artery wall (endothelium), reduced LDL oxidation, and a decreased prothrombotic state. Ezetimibe’s (Zetia’s ) value has been long known to simply decrease the LDL load, without any documented additive affects, as noted with statins. As documented in the ENHANCE trial, the addition of zetia did effectively pull the LDL down further without any apparent harm. Further analyses of inflammatory markers remains pending.
Statin therapy remains an essential element in the treatment and stability of vascular disease. Zetia remains an additional therapy to further lower LDL, if needed. Neither statins nor zetia have the ability to impact the many other important lipid parameters, such as HDL, ApoB, and triglycerides. Therefore, other agents are often necessary to treat the complex lipid issues associated with atherosclerosis. Niacin ER is the only drug that treats all of the lipid parameters in a positive way.
For those who are currently taking Zetia, based on the ENHANCE data, I find no safety concerns to date that advocate going off this medication. This trial suggests what we have long known; the atherosclerotic process goes well beyond an isolated LDL issue. If someone has a difficult to treat LDL issue, Zetia continues to be an option to pull down LDL if the combination of statin and niacin ER are unable to reach optimal goals.
Please see the attached statement by the National Lipid Association regarding the ENHANCE trial. Please do not hesitate to call if you have any questions regarding your current treatment plan.
Amy Doneen ARNP
The Heart Attack & Stroke Prevention Center