Cardiovascular Prevention and Rehabilitation

The answer first

Prevention is absolute-risk medicine: you treat a person's probability of an event, not a number on a lipid panel. Four rules carry you through almost every DWE question, every DCE long case, and every prevention clinic decision [1]:

1. Treat the risk, not the number. A statin is prescribed against calculated absolute cardiovascular risk — or against established disease, familial hypercholesterolaemia, or another condition that makes the patient high-risk by definition. The LDL value alone never answers "should I treat?" [1] [5].
2. LDL lowering is dose-dependent, additive and boringly reliable. Each 1.0 mmol/L fall in LDL cuts major vascular events by about a fifth, whatever drug achieves it — statin, ezetimibe, or PCSK9 antibody. Start high-intensity statin, then climb the ladder to target [5] [8] [9].
3. Secondary prevention is a bundle, and rehabilitation is part of it. Post-ACS, the statin, the antiplatelet, the beta-blocker, the ACE inhibitor and the cardiac rehabilitation referral each carry event-reduction evidence. Forgetting the referral is forgetting a mortality intervention [15] [22] [23].
4. Primary prevention in the elderly and low-risk is where harm hides. Aspirin for primary prevention in people over 70 causes more bleeding than benefit; statin decisions in low-risk people need absolute numbers, not relative ones [16].

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Treat the risk, not the number

Absolute risk is the probability of a cardiovascular event over a defined period, computed from the whole risk-factor profile rather than any single factor. It is the only honest way to decide preventive treatment, because the benefit of a statin is proportional to baseline risk while the harms are roughly constant — the same drug that saves one in twenty high-risk patients over a decade does almost nothing measurable for a low-risk one [1] [5].

Who to assess. The 2023 Australian guideline recommends assessing absolute risk in all adults from 45 years (from 30 years for Aboriginal and Torres Strait Islander adults, and from 35 years for people with diabetes), using the AusCVDRisk calculator — a PREDICT-derived, Australian-recalibrated equation that replaced the old Framingham-derived NVDPA charts [1]. QRISK3 does the same job in the UK and adds inputs the older tools lacked — chronic kidney disease, atrial fibrillation, corticosteroids, severe mental illness and erectile dysfunction — validated in more than ten million patients [2].

The bands. Australia now uses three five-year risk categories: low (below 5%), intermediate (5% to below 10%), and high (10% or more). High risk earns blood-pressure and lipid-modifying treatment alongside lifestyle; intermediate risk earns a full discussion with reclassification factors (coronary artery calcium, Lp(a), family history, ethnicity, social deprivation) before deciding [1]. NICE expresses the same logic through QRISK3: offer atorvastatin 20 mg when ten-year risk reaches 10% [2].

Communicating risk is half the consultation. Percentages mean little to patients; "of 100 people like you, about 12 will have a heart attack or stroke in the next ten years — this tablet brings that to about 9" lands better. Shared decision-making around that number is a formal recommendation of the Australian guideline, not a courtesy [1].

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Lipids: the treatment ladder

Lifestyle is the foundation for everyone; drugs are layered on by risk. The ladder has four rungs, and each rung has a named trial behind it [5] [8] [9].

Rung 1 — statins, at the right intensity. Statins block HMG-CoA reductase, upregulate hepatic LDL receptors, and remain the cheapest, most proven cardiovascular drug after aspirin in secondary prevention. High-intensity dosing (atorvastatin 40–80 mg or rosuvastatin 20–40 mg daily) lowers LDL by 50% or more and is the default after ACS and in very-high-risk patients; moderate intensity (atorvastatin 10–20 mg, rosuvastatin 5–10 mg, simvastatin 20–40 mg) lowers LDL by roughly a third and suits many primary-prevention patients [6] [7]. More intensive regimens win: in the CTT 2010 meta-analysis, pushing LDL a further 0.5 mmol/L down with intensive versus standard statin dosing cut major vascular events a further 15% [6].

Targets give the ladder its direction. The ESC prevention framework sets LDL goals by risk tier: very high risk — below 1.4 mmol/L and at least a 50% reduction from baseline; high risk — below 1.8 mmol/L; moderate risk — below 2.6 mmol/L. Australian practice tracks the same logic, checking lipids 6–8 weeks after starting or changing therapy [1] [6].

Rung 2 — ezetimibe. IMPROVE-IT randomised 18,144 post-ACS patients to simvastatin 40 mg with or without ezetimibe 10 mg: median LDL fell to 1.4 versus 1.8 mmol/L, and the composite endpoint fell with it (absolute benefit about 2% over seven years). The trial matters beyond its modest effect size — it proved that a non-statin LDL-lowering drug reduces events in proportion to LDL lowering, validating LDL as the causal target [8] [5].

Rung 3 — PCSK9 monoclonal antibodies. Evolocumab 140 mg every two weeks (FOURIER, 27,564 patients with established ASCVD on statins) drove median LDL to 0.78 mmol/L and cut the key composite of cardiovascular death, MI or stroke by 20% [9]. Alirocumab after recent ACS (ODYSSEY OUTCOMES) cut the primary composite by 15% with a suggestion of mortality benefit in those treated longest and with baseline LDL at or above 2.6 mmol/L [10]. These drugs are for the patient still above target — or with recurrent events — despite maximally tolerated oral therapy; cost and access criteria keep them behind ezetimibe in the queue [9] [10].

Bempedoic acid is the rung for the statin-intolerant: an oral ATP-citrate lyase inhibitor (180 mg daily) that is inactive in skeletal muscle and so largely spares it. CLEAR Outcomes randomised 13,970 statin-intolerant patients and found a 13% relative reduction in the four-component MACE composite — the first outcomes evidence for a drug built specifically for this population [11].

[6] [9]

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The evidence spine — how we know LDL is causal

Prevention examiners expect you to quote trials, not vibes. Four studies form the spine [3] [4] [5] [6]:

The primary-versus-secondary distinction is about absolute benefit. Secondary prevention treats a population whose event rate is several per cent per year, so the number needed to treat is small and every high-risk patient benefits. In primary prevention the same relative reduction applies to a much smaller absolute risk, which is why the risk calculation — not the cholesterol — is the gatekeeper for treatment [1] [5].

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Statin intolerance — and the nocebo elephant

Statin-associated muscle symptoms (SAMS) are the commonest reason prevention fails in practice. The pivotal modern evidence is SAMSON: a crossover n-of-1 trial in 60 patients who had abandoned statins through side effects, randomising months on atorvastatin 20 mg, placebo, and no treatment. Symptom intensity on statin and placebo was statistically indistinguishable — the nocebo effect accounted for about 90% of the symptom burden — and half the patients were able to restart statins within six months of seeing their own data [13].

This does not mean symptoms are imaginary; it means the attribution is usually wrong, and the physician's job is a structured workup rather than a reflex cessation [13] [5].

[11] [13]

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Beyond LDL: triglycerides, Lp(a) and familial hypercholesterolaemia

Triglycerides. Moderate hypertriglyceridaemia marks residual risk in statin-treated patients. REDUCE-IT randomised 8,179 statin-treated patients (established CVD, or diabetes plus risk factors) with fasting triglycerides 1.5–5.6 mmol/L to icosapent ethyl 2 g twice daily — purified EPA, not fish-oil shop omega-3 — versus mineral-oil placebo: the primary composite fell 25% and cardiovascular death fell 20%. This is the only triglyceride-directed therapy with hard outcomes evidence; mixed fish oils and fibrates do not share it [12].

Lipoprotein(a) is a genetically determined LDL-like particle whose level is barely moved by lifestyle or statins. The EAS consensus flags concentrations above about 50 mg/dL (roughly the 80th percentile) as a risk-enhancing finding. Measure it once in adults with premature CVD, familial hypercholesterolaemia, a strong family history, or borderline risk decisions — a high result upgrades risk, tightens every other factor, and strengthens the case for aggressive LDL lowering while targeted therapies complete their trials [20].

Familial hypercholesterolaemia is the prevention diagnosis you must not miss: autosomal dominant, roughly 1 in 250–500 people, LDL very high from birth, and coronary disease a decade or more early if untreated. The EAS consensus makes three points every physician should carry: it is common and underdiagnosed; cascade screening of first-degree relatives is the most cost-effective case-finding in preventive cardiology; and treatment starts early with high-intensity statins, escalating to ezetimibe and PCSK9 antibodies to reach targets [19].

Score 6 or more makes probable-to-definite FH; 3–5 is possible and triggers family screening regardless [19].

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Lifestyle — with numbers, not slogans

Lifestyle advice fails when it is vague. The evidence-backed prescription has quantities attached [14] [24] [25].

• Mediterranean diet. PREDIMED randomised about 7,400 high-risk Spaniards without CVD to a Mediterranean diet supplemented with extra-virgin olive oil or nuts versus low-fat control; major cardiovascular events fell by about 30%. The republished analysis (after randomisation corrections) preserved the result. Prescribe the pattern — olive oil, nuts, legumes, fish, vegetables, minimal processed food — not a supplement [14].
• Exercise. At least 150 minutes of moderate aerobic activity weekly (or 75 vigorous) plus resistance work is the guideline floor. The dose-response is real: each 1-MET increment in cardiorespiratory fitness tracks with about 13% lower all-cause mortality and 15% fewer cardiovascular events in meta-analysis [25].
• Smoking cessation is the single biggest intervention. In the Lung Health Study's 14.5-year follow-up, a sustained cessation intervention cut all-cause mortality — the rare lifestyle trial with a survival endpoint. Every prevention consult to a smoker starts here, combining behavioural support with pharmacotherapy (varenicline, NRT, bupropion) rather than advice alone [24].
• Alcohol. There is no cardiovascular indication for alcohol; keep within national low-risk limits and do not "prescribe" red wine for the heart — the PREDIMED benefit belongs to the dietary pattern, not the bottle [14].

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Blood pressure and diabetes — the risk multipliers

Hypertension and diabetes rarely appear in the prevention exam as themselves; they appear as the factors that push a borderline risk calculation over the treatment line [1] [21].

SPRINT randomised 9,361 non-diabetic adults at high cardiovascular risk to systolic targets below 120 versus below 140 mmHg: the intensive target cut the primary composite by 25% and all-cause death by 27%, at the cost of more hypotension, syncope, electrolyte disturbance and acute kidney injury. The lesson for prevention is that blood pressure targets, like lipid targets, tighten as risk rises — and that intensive treatment trades absolute benefit against monitoring burden [21].

For diabetes, the statin evidence is unambiguous: CTT included large diabetic cohorts and found the same proportional LDL benefit as in non-diabetics, which is why most adults with diabetes over 40 earn a statin on risk grounds even when lipids look unremarkable [5]. What diabetes no longer earns by default is aspirin — see the controversy section below [17].

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The post-ACS secondary prevention bundle

Secondary prevention is where the bundle lives. Each component has its own trial lineage, and the DCE examiner wants to hear you prescribe all five deliberately [22] [23] [26]:

Add the surrounding work: influenza vaccination, depression screening (post-MI depression is common and worsens outcomes), driving and return-to-work advice, and explicit smoking-cessation pharmacotherapy for smokers [15] [24].

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Cardiac rehabilitation

Cardiac rehabilitation is a structured, multidisciplinary secondary-prevention program — and the Cochrane evidence says it works: across 63 trials and nearly 15,000 patients, exercise-based rehabilitation reduced cardiovascular mortality by about 26% (relative risk 0.74) and hospital readmissions, with improved quality of life, even in the modern statin-and-PCI era [15].

[15]

Who gets referred: every post-ACS patient, post-revascularisation (PCI or CABG), stable angina, and heart failure with reduced ejection fraction. The scandal is utilisation — referral and attendance rates sit far below eligibility everywhere, with women, rural patients, the elderly and the socioeconomically deprived least likely to attend. Naming those barriers, and offering home-based or telehealth models, is the consultant-level answer to "is rehab worth it?" [15].

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Primary prevention controversies — where guidelines moved

Aspirin has left primary prevention. Three 2018 trials closed the era: ASPREE (19,114 healthy people aged 70 and over) found aspirin 100 mg gave no cardiovascular benefit and more major haemorrhage, with a signal of higher all-cause mortality [16]; ASCEND (15,480 people with diabetes and no CVD) found vascular benefits roughly cancelled by major bleeding [17]; and ARRIVE (12,546 moderate-risk adults) found no event reduction with doubled gastrointestinal bleeding [18]. The current rule: aspirin is for secondary prevention; in primary prevention it is an individualised exception for selected high-risk, low-bleeding-risk younger adults — never routine, and essentially never after 70 [16] [18].

Coronary artery calcium scoring is the tiebreaker for the undecided middle: a CAC of zero downgrades an intermediate-risk estimate enough to defer a statin in many patients, while a high score upgrades. It appears in the Australian guideline as a reclassification tool for intermediate risk — use it when the result will genuinely change the decision [1].

How low should LDL go? FOURIER achieved median LDL 0.78 mmol/L with no new safety signal over its follow-up, and the CTT analyses show a log-linear benefit with no floor — the exam-safe statement is "lower is better, at least down to the levels achieved in the outcomes trials" [6] [9].

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The DCE angles

Long case. The classic defence is the post-ACS patient with multimorbidity — CKD, diabetes, hypertension — complicated by statin-associated muscle symptoms. The examiner watches three things: whether you defend the whole bundle rather than the drug of the moment; whether your statin plan is a protocol (exclude mimics, dechallenge, rechallenge, alternate-day dosing, ezetimibe or bempedoic acid backbone) rather than capitulation; and whether rehabilitation, smoking, depression and adherence feature as seriously as the pharmacology [11] [13] [15].

Short case. The risk-factor examination: blood pressure done properly, BMI and waist circumference, eyes for xanthelasma and corneal arcus, tendons for xanthomata (Achilles and extensor tendons of the hands), hands for nicotine staining, and pulses for established disease. Tendon xanthomata are the highest-value physical sign in preventive cardiology — near-pathognomonic of FH and worth 6 Dutch Lipid Clinic points on their own [19].

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Exam traps, collected

References

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