This study is enrolling participants with risk factors for heart or blood vessel events (e.g. heart attack, stroke, etc) who also have an elevated lipoprotein a (Lp(a)), which is a sticky particle in the blood that carries cholesterol. The first part of the study involves testing the Lp(a) level and if elevated then participants will be invited to be a part of a study testing the investigational medication olpasiran. Investigational means it has not been approved for commercial use by the Food and Drug Administration. The study medication is given as a shot just under the skin every 3 months. This study is a randomized study meaning participants are assigned by chance to either receive olpasiran or placebo. Placebo looks like the real medication but has no active ingredients. Participants have a 50:50 chance of being assigned to either group but will not know which group they are in. Study related procedures include physical exams, blood work, vital signs, electrocardiogram (ECG - a tracing of the heart's electrical activity) and study medication administration. This study is expected to last about three and a half to five and a half years and involve between 16 to 28 visits.