Updates from American College of Cardiology Pertinent to Primary Care Physicians

Tyler Gluckman, MD, Medical Director, Clinical Transformation, Providence St. Vincent Heart and Vascular Institute, Portland, OR, presented updates from the American College of Cardiology (ACC) Scientific Sessions outlining topics significantly impacting the work of primary care physicians (PCPs) for their patients with cardiovascular disease (CVD).

Notable among these issues is the use of newly approved PCSK9 inhibitors in managing patients atâ€risk for hypercholesterolemia and new recommendations for transcatheter aortic valve replacement (TAVR) in aortic stenosis versus surgical replacement.

After reviewing various lifestyle interventions that are known to lower low-density lipoprotein (LDL), Gluckman concluded that even if all of these interventions were pursued by individual patients (resulting in a projected 30% to 45% reduction in LDL), this would still not bring LDL levels down low enough, and that cholesterol-lowering medications (statins) would be required to mitigate the risk of CVD.

According to Gluckman, “The thing that all of us know, though, is it is very hard to do even one of these interventions, let alone all of these together,” which mandates the use of medications to lower LDL to safe levels. Upon reviewing a meta-analysis of 8 randomized statin trials, lowering LDL levels always translated to improved hazard ratios. In his practice, Gluckman has attempted to get LDL levels as low as possible in his patients, with some patients in single digits of mg/dl.

There was no minimum level of LDL that he would consider inherently dangerous, citing the LDL level of newborns (30 to 35 mg/dl) as support for this view. Regarding a subgroup analysis of the meta-data, Gluckman said, “The data suggest that 40% or more of individuals on even high-dose statins might not be able to get their LDL below 70 mg/dl.”

Gluckman provided background on how PCSK9 promotes the degradation of the LDL receptor and prevents it from recycling to the cell membrane. Fewer LDL receptors on cell surfaces result in more LDL remaining in the bloodstream. Inhibitors of PCSK9 include monoclonal antibodies that bind to PCSK9 and prevent its association with LDL receptor molecules, thereby providing more LDL receptors to help remove LDL from the blood.

Gluckman also reviewed data from trials on which the ACC based new recommendations for repair of aortic stenosis.

Approximately 30,000 surgical aortic valve replacement (SAVR) procedures are performed each year in the US. Now the ACC is recommending that severe aortic stenosis patients at high- or intermediate surgical risk undergo TAVR instead of SAVR, which are characterized as mainstay treatments for severe, symptomatic aortic stenosis, because they improve symptoms and survival.

In differentiating the 2 procedures, Gluckman said the key advantage of TAVR is that the device is introduced via the femoral artery instead of requiring sternotomy, resulting in lower mortality and only overnight hospital stays versus multiple days for SAVR.

Although safer than SAVR, Gluckman listed the potential TAVRâ€related postâ€procedure complications, which included paravalvular aortic regurgitation, conduction defects, thromboembolic events, and reduced prosthesis durability.

Regarding extending the recommendation of the safer, less expensive procedure (TAVR) to low-risk patients with severe aortic stenosis, Gluckman concluded, “For those at low surgical risk, the current guideline recommendations are still to proceed with SAVR. However, studies are underway asking whether TAVR the way that we should proceed with those at low surgical risk.”