lipoprotein(a)

Lp(a) is a genetically determined (~90%, LPA gene), LDL-like particle causally linked to ASCVD and calcific aortic stenosis (Mendelian randomisation). Levels are stable over a lifetime → measure once (exceptions: menopause transition, new CKD/nephrotic syndrome/hypothyroidism, pregnancy). CCS (2021, reaffirmed 2026) and ACC/AHA (2026, Class I) both recommend one-time measurement in all adults — yet no completed outcomes trial has shown that lowering Lp(a) reduces events. Statins do not lower Lp(a); PCSK9 inhibitors lower it ~15–30%. Management = intensify conventional risk factor control, not chase the Lp(a) number. In the CCS framework, Lp(a) is a risk modifier applied to the FRS (alongside family history, hs-CRP, CAC) — it does not replace or override it. Always frame in absolute risk: risk is dose-dependent and multiplicative — ~40% relative increase at ≥125 nmol/L, ~2× at ~200–250 nmol/L, ~4× at ≥430 nmol/L (FH-equivalent).

what is Lp(a)

apolipoprotein(a) covalently bound to an LDL-like particle; carries oxidised phospholipids
pro-atherogenic, pro-inflammatory, pro-thrombotic (inhibits fibrinolysis via homology to plasminogen)
unaffected by diet, exercise, or statins
distribution highly skewed — elevated in ~20% of the population; more prevalent in Black and South Asian populations

guideline recommendations

All major guidelines now recommend one-time measurement in every adult — CCS 2021 (strong recommendation, reaffirmed in the CCS 2026 framework), ACC/AHA 2026 (Class I), ESC/EAS 2019 (Class IIa). “Elevated” is essentially the same everywhere: ≥50 mg/dL / ≥100–125 nmol/L (parallel cutpoints, not conversions). ESC adds a very-high tier at >180 mg/dL (~430 nmol/L), treated as FH-equivalent.

Canadian risk stratification uses the FRS — not PREVENT (US, used by ACC/AHA 2026 with different thresholds: borderline 3–5%, intermediate 5–10%) or SCORE2 (Europe). FRS does not incorporate Lp(a); apply it as an external risk modifier.

management by risk stratum

Elevated Lp(a) + low FRS (<10%)

can be helpful to counsel in absolute terms: “your 10-year cardiovascular risk remains low; Lp(a) adds a small amount to that”
no statin indication on Lp(a) alone if otherwise low risk; if FRS 5–9.9% with elevated cholesterol, elevated Lp(a) can tip toward statin via shared decision-making
reinforce modifiable risk factors (diet, exercise, smoking, BP, glycaemia); recheck standard risk factors in 3–5 years
consider CAC (see below) if the result would change management

Elevated Lp(a) + intermediate FRS (10–19.9%)

Lp(a) supports statin initiation in patients not otherwise meeting LDL/apoB treatment thresholds — the threshold to treat is already low; CAC can further refine but often unnecessary
optimise LDL-C to CCS targets (LDL <2.0 mmol/L or >50% reduction; apoB <0.8 g/L); some advocate more aggressive targets when Lp(a) is elevated, though trial evidence for that specific strategy is lacking
PCSK9 inhibitors lower Lp(a) ~15–30%; in ODYSSEY OUTCOMES (Bittner, 2020), alirocumab-mediated Lp(a) reduction was independently associated with MACE reduction after adjusting for LDL-C change — suggestive, not proven

All elevated Lp(a)

intensify standard ASCVD risk factor management
cascade screening of first-degree relatives
low-dose aspirin: open question — post-hoc primary-prevention data suggest benefit at high Lp(a) (Lacaze, JACC 2022), but no prospective evidence. Shared decision-making if bleeding risk is low
no Lp(a)-specific pharmacotherapy outside trials. (Lipoprotein apheresis lowers Lp(a) ~30–35%/session; FDA-approved for Lp(a) ≥60 mg/dL with FH + documented CAD/PAD; registry data only, and availability in Canada is very limited.)

Elevated Lp(a) + aortic stenosis

causal link to calcific AS, but no therapy slows progression; standard AS surveillance — Lp(a) does not change monitoring intervals or echo criteria

CAC — risk reclassification

CCS endorses CAC in intermediate-risk (FRS 10–20%) asymptomatic adults ≥40 when treatment is unclear; may be considered in low-risk adults >40 with genetic indicators (elevated Lp(a), FH). Best use case: elevated Lp(a) + borderline/intermediate risk + patient unsure about a statin.

CAC	Interpretation with elevated Lp(a)	Action
0	strong negative reclassifier — substantially lowers but may not fully neutralise Lp(a)-attributable risk	reasonable to defer statin in most; lifestyle; recheck CAC in 5–10 yrs (shorter if diabetes, heavy smoking)
1–99	early atherosclerosis — Lp(a) may be contributing	strengthens case for statin; shared decision-making
≥100 or ≥75th percentile	established subclinical disease	statin indicated; consider aggressive LDL-C targets

A 2026 multicohort analysis (Bhatia, JACC 2026; n>11,000) found elevated Lp(a) raises ASCVD risk across all CAC strata including CAC = 0 — though absolute event rates with CAC = 0 remain low. CAC = 0 reassures; it does not erase Lp(a) risk.
CAC is least reliable in patients <45–50 (especially pre-menopausal women) — atherosclerosis may be non-calcified. CAC = 0 in a 35-year-old with Lp(a) >300 nmol/L is far less reassuring than in a 55-year-old; here the decision rests on clinical judgement.

Other tests: CIMT — abandoned for individual prediction, not guideline-recommended. CT coronary angiogram — no role in asymptomatic low-risk patients (incidental-finding harms likely outweigh benefit). hs-CRP — marginal added reclassification; no specific interaction with Lp(a).

treatment landscape

statins: no Lp(a) lowering (may trivially raise it) — still first-line for overall risk
PCSK9 inhibitors: ~15–30% Lp(a) reduction (see above); not designed to test Lp(a)-lowering per se
niacin: lowers Lp(a) ~25–40% but no event reduction (AIM-HIGH (2011), HPS2-THRIVE (2014)) — do not use for this indication

Pipeline (none proven; status mid-2026):

Agent	Mechanism	Lp(a) ↓	Trial
pelacarsen	antisense oligonucleotide	~55–80%	HORIZON, phase III ongoing (n≈8,000)
olpasiran	siRNA	~90–98%	OCEAN(a)-OUTCOMES, phase III ongoing (n≈6,000)
others (lepodisiran, zerlasiran, muvalaplin)	siRNA / oral small molecule	~45–98%	phase II–III, earlier

Even with positive trials, an open question remains whether short-term pharmacological reduction offsets lifelong genetic exposure.

measurement pitfalls

units: nmol/L (molar, preferred) vs mg/dL (mass); the ×2.5 conversion is approximate because apo(a) isoform size varies
assays: older isoform-sensitive assays overestimate Lp(a) with small apo(a) isoforms; isoform-insensitive immunoassays preferred but not universal
Lp(a) cholesterol is included in reported LDL-C → with very high Lp(a), true LDL-C is lower than reported (corrected LDL-C ≈ LDL-C − [Lp(a) mg/dL × 0.3]; correction factor approximate and debated)