# Video research-update insert: LDL Particle Concentration as a Causal Driver of Atherosclerotic Cardiovascular Disease

Editorial script and storyboard insert, 5 October 2026. No rendered video. Read alongside the original review; no new grade is announced.

## Narration

Human genetics, multiple drug classes and experimental retention evidence support a causal role for atherogenic lipoprotein exposure. Remaining gaps concern the best exposure metric, lifetime treatment timing and populations in which lowering does not reduce the measured outcome.

In the 1994 study, simvastatin reduced coronary events and improved survival in established coronary disease. A drug effect is not an isolated manipulation of particle count versus cholesterol content. [P7968073]

In the 2015 study, adding ezetimibe lowered LDL further and improved cardiovascular outcomes. The achieved exposure changes multiple correlated lipid measures. [P26039521]

In the 2025 study, evolocumab reduced first events in high-risk people without previous myocardial infarction or stroke. Atherosclerosis or diabetes eligibility is not unrestricted low-risk primary prevention. [P41211925]

The next discriminating question is: When does LDL cholesterol cease to represent the causal exposure adequately? Particle number, particle type and cholesterol content may diverge while conventional LDL-C remains correlated. Prospective discordance analyses and orthogonal instruments with conditional-strength checks; measure apoB, LDL-C, remnants and lipoprotein(a).

The timeline shows selected changes in evidence, not inevitable progress or proof of a single cause. The review’s archived grade remains unchanged; the depth of source reading is documented in the update.

## Storyboard and source locks

| Insert | Visual | Narration anchor | Sources |
|---|---|---|---|
| Opening | Claim and bounded update statement | First paragraph | Review claim and source ledger |
| Timeline 1994 | Dated study card with design, result and limit | Simvastatin reduced coronary events and improved survival in established coronary disease. | [P7968073](https://pubmed.ncbi.nlm.nih.gov/7968073/) |
| Timeline 2015 | Dated study card with design, result and limit | Adding ezetimibe lowered LDL further and improved cardiovascular outcomes. | [P26039521](https://pubmed.ncbi.nlm.nih.gov/26039521/) |
| Timeline 2025 | Dated study card with design, result and limit | Evolocumab reduced first events in high-risk people without previous myocardial infarction or stroke. | [P41211925](https://pubmed.ncbi.nlm.nih.gov/41211925/) |
| G1 | Question → competing explanation → discriminating test | When does LDL cholesterol cease to represent the causal exposure adequately? | [P32203549](https://pubmed.ncbi.nlm.nih.gov/32203549/), [P16554528](https://pubmed.ncbi.nlm.nih.gov/16554528/), [P26039521](https://pubmed.ncbi.nlm.nih.gov/26039521/), [P28304224](https://pubmed.ncbi.nlm.nih.gov/28304224/) |
| G2 | Question → competing explanation → discriminating test | Why do advanced dialysis populations differ? | [P16034009](https://pubmed.ncbi.nlm.nih.gov/16034009/), [P7968073](https://pubmed.ncbi.nlm.nih.gov/7968073/), [P28304224](https://pubmed.ncbi.nlm.nih.gov/28304224/) |
| G3 | Question → competing explanation → discriminating test | How much benefit comes from earlier and longer exposure reduction? | [P16554528](https://pubmed.ncbi.nlm.nih.gov/16554528/), [P41211925](https://pubmed.ncbi.nlm.nih.gov/41211925/), [P36876740](https://pubmed.ncbi.nlm.nih.gov/36876740/) |
| G4 | Question → competing explanation → discriminating test | Which residual risks are not mediated by LDL lowering? | [P12066187](https://pubmed.ncbi.nlm.nih.gov/12066187/), [P32203549](https://pubmed.ncbi.nlm.nih.gov/32203549/), [P28304224](https://pubmed.ncbi.nlm.nih.gov/28304224/) |

## Editorial constraints

- Use the primary-source links shown above and keep the inference limit on screen with each milestone.
- Do not narrate an abstract check as complete-paper examination, a model result as human proof, or an unresolved inference as absence of all research.
- Preserve trial endpoint hierarchy, cohort reuse, correction notices and online/issue dates.
- Use original graphics made from this ledger. Publisher figure imagery has not been cleared or supplied for video reuse.
- Confirm any change in verdict through a separate documented HSEF review; this insert makes none.