Lipoprotein(a) and Benefit of PCSK9 Inhibition in Emergency Complex Higher-risk and Indicated Patients

There is a large population of patients classified as complex higher-risk and indicated patients (CHIPs) in China with a poor prognosis. The treatment of these patients is complex and challenging, especially when acute cardiac events occur, such as acute coronary syndrome (ACS) or heart failure. Pharmacotherapy and some mechanical circulatory support (MCS) therapeutic devices can provide stable hemodynamic support for CHIPs-percutaneous coronary intervention (PCI). LDL-C is an important pathogenic factor in atherosclerosis, and the target of blood lipid control. Recent studies have revealed that lipoprotein(a) [Lp(a)], which is formed when a covalent bond between apolipoprotein(a) and apolipoprotein B-100 is made, produces an LDL-like particle. This particle is an independent risk factor for the development of atherosclerosis, and is closely correlated to stent thrombosis and restenosis. Furthermore, this requires active intervention. PCSK9 inhibitors have been used in lipid-lowering treatment, and preventing atherosclerosis. The present study explores the efficacy of PCSK9 inhibitors in CHIPs-ACS, and the association between the change in Lp(a) and survival after 2 years of follow-up.

The present real-world, prospective control study enrolled 321 CHIPs-ACS who underwent emergency PCI from August 2019 to November 2020, and these patients were followed up for 2 years. These patients were divided into two groups: PCSK9 group (n=161) given the combined PCSK9 inhibitor (140 mg of evolocumab every 2 weeks) and statins-based therapy, and SOC group (n=160) treated with statin-based lipid-lowering therapy alone. Then, the change in lipid index was measured, and the cardiovascular (CV) event recurrence rate was evaluated after one month and 2 years. Afterwards, the contribution of serum lipid parameters, especially the Lp(a) alteration, in patients with earlier initiation of the PCSK9 inhibitor to the CV outcome was analyzed.

The LDL-C level was significantly reduced in both groups: 52.3% in the PCSK9 group and 32.3% (P<0.001) in the SOC group. It is noteworthy that the Lp(a) level decreased by 13.2% in the PCSK9 group, but increased by 30.3% in the SOC group (P<0.001). Furthermore, the number of CV events was not significantly different between the PCSK9 and SOC groups after the 2-year follow-up period. In the PCSK9 group, the Lp(a) reduction was associated with the baseline Lp(a) levels of the patients (r² =-0.315, P<0.001). Moreover, the decrease in Lp(a) contributed to the decline in CV events in patients who received ACS CHIPs-PCI, and the decrease in Lp(a) level was independent of the LDL-C level reduction.

The early initiation of PCSK9 inhibitors can significantly reduce the LDL-C and Lp(a) levels in ACS CHIPs-PCI. However, further studies are needed to confirm whether PCSK9 inhibitors can reduce the incidence of CV disease in CHIPs.