7.3 Heart Failure & Anticoagulation Management

HFrEF: The Four Pillars

Heart failure with reduced ejection fraction (HFrEF) — left ventricular ejection fraction ≤40% — is treated with four disease-modifying drug classes that should all be started promptly and up-titrated to target or maximally tolerated doses:

1. ARNI/ACE inhibitor/ARB: sacubitril/valsartan is preferred where tolerated and affordable; otherwise an ACE inhibitor (ramipril, enalapril, perindopril) or, if cough/intolerance, an ARB. When switching from an ACE inhibitor to sacubitril/valsartan, observe a mandatory 36-hour washout to minimize angioedema risk.
2. Evidence-based beta-blocker: only bisoprolol, carvedilol, metoprolol succinate, or nebivolol carry HFrEF outcome data — start low, go slow, and ensure the patient is euvolemic before initiation.
3. Mineralocorticoid receptor antagonist (MRA): spironolactone or eplerenone for patients remaining symptomatic; counsel about gynecomastia with spironolactone.
4. SGLT2 inhibitor: dapagliflozin or empagliflozin 10 mg daily, beneficial across the ejection fraction spectrum and in patients with or without diabetes.

Loop diuretics (furosemide, bumetanide) relieve congestion and improve symptoms but do not improve survival — they are for fluid management, not a prognostic pillar.

Up-Titration Monitoring

Pharmacists anchor the titration clinic. At each dose increase (typically every 2–4 weeks, doubling toward target), check blood pressure, heart rate, potassium, creatinine, and eGFR:

• Symptomatic hypotension: first reduce or space non-prognostic agents (loop diuretic if not congested) before sacrificing pillar drugs.
• Accept a creatinine rise up to 30% after RAAS blockade; investigate beyond that.
• Start an MRA only if potassium is <5.0 mmol/L and eGFR adequate (>30 mL/min/1.73 m²); recheck potassium and creatinine within 1–2 weeks of starting and after each increase. Stop or halve for potassium ≥5.5–6.0 mmol/L per local protocol.
• Beta-blocker titration requires resting heart rate above ~55–60 bpm and no symptomatic hypotension.

Self-Care Counseling, Classification, and Red Flags

Teach every patient: weigh each morning after voiding, before breakfast, on the same scales, and report a gain of more than 2 kg (about 3–5 lb) in 3 days; restrict fluid to roughly 1.5–2 L/day if congested or hyponatremic; limit salt (avoid salt substitutes containing potassium chloride when on an MRA or RAAS blocker); keep vaccinations current (influenza, pneumococcal, COVID-19); and maintain activity or cardiac rehabilitation.

The New York Heart Association (NYHA) classification grades symptoms: class I, no limitation; II, symptoms on ordinary exertion; III, symptoms on minimal exertion; IV, symptoms at rest. It guides therapy (e.g., MRA and ARNI decisions) and tracks trajectory. Heart failure with preserved ejection fraction (HFpEF, EF ≥50%) lacks the broad prognostic drug base of HFrEF: manage congestion with diuretics, control comorbidities aggressively (hypertension, AF, diabetes, obesity), and note that SGLT2 inhibitors reduce HF hospitalization across this group too.

Exacerbation red flags requiring urgent review: new or worsening orthopnea or paroxysmal nocturnal dyspnea, rapid weight gain, increasing peripheral edema or ascites, and confusion in the elderly. Counsel patients and prescribers to avoid NSAIDs (sodium retention, renal harm), thiazolidinediones (fluid retention), and non-dihydropyridine calcium channel blockers verapamil and diltiazem (negative inotropy) in HFrEF — a classic pharmacist-intervention question.

Anticoagulation in Atrial Fibrillation: Risk Assessment

Stroke prevention in AF starts with the CHA2DS2-VASc score: congestive heart failure, hypertension, age ≥75 (2 points), diabetes, prior stroke/TIA/thromboembolism (2 points), vascular disease, age 65–74, and female sex category. Anticoagulation is generally recommended at ≥2 in men and ≥3 in women, and should be considered at 1 in men and 2 in women; patients at genuinely low risk (0 in men, 1 in women) need none. HAS-BLED (hypertension, abnormal renal/liver function, stroke, bleeding history, labile INR, elderly >65, drugs/alcohol) identifies modifiable bleeding risks — uncontrolled hypertension, interacting drugs, NSAID/antiplatelet overuse, alcohol — but a high score is a prompt to mitigate risk and monitor, not a reason to withhold anticoagulation. Aspirin is not an acceptable substitute for stroke prevention in AF.

Warfarin Clinic Workflow

Warfarin remains relevant for mechanical heart valves and moderate-to-severe rheumatic mitral stenosis (where DOACs are contraindicated) and severe renal impairment. Target INR 2.0–3.0 for AF and most VTE (2.5–3.5 for mechanical mitral valves). Workflow essentials:

• Test frequently during initiation (every few days), then at lengthening intervals once stable — at most every 12 weeks; aim for time in therapeutic range above ~65–70%.
• Counsel consistency, not avoidance, of vitamin K–rich foods (green leafy vegetables); sudden dietary shifts destabilize INR.
• Vigilance for interactions: antibiotics (metronidazole, trimethoprim-sulfamethoxazole, macrolides), amiodarone, and antifungals raise INR; carbamazepine, rifampicin, and St John's wort lower it. Recheck INR within days of any interacting drug start or stop.
• Missed dose: take it the same day when remembered; never double the next dose; record the miss and inform the clinic.
• Concomitant antiplatelets and NSAIDs sharply increase bleeding — deprescribe unless clearly indicated.

DOAC Counseling

Direct oral anticoagulants — apixaban, rivaroxaban, dabigatran, edoxaban — are first-line for non-valvular AF and VTE. Core counseling:

• Adherence is critical: half-lives are around 12–17 hours, so even one missed dose erodes protection. There is no routine INR safety net.
• Take rivaroxaban 15/20 mg with food for absorption; keep dabigatran in its original bottle (moisture-sensitive) and warn about dyspepsia.
• Dosing depends on renal function, age, and weight — check creatinine clearance at baseline and at least annually (more often in the elderly or CKD). Dabigatran is avoided when CrCl is below 30 mL/min; DOACs generally are not used below CrCl 15 mL/min.
• Missed-dose rules: for twice-daily agents, take within about 6 hours of the scheduled time; for once-daily rivaroxaban, within about 12 hours — otherwise skip and resume the next dose without doubling.

VTE Duration, Bridging, and Bleeding Management

A provoked deep vein thrombosis or pulmonary embolism (surgery, immobilization, estrogen) is treated for 3 months; unprovoked or cancer-associated events usually warrant extended therapy beyond 3–6 months after reassessing bleeding risk. Peri-procedurally, warfarin patients at high thrombotic risk (mechanical valves, recent VTE, high CHA2DS2-VASc) may need bridging with a parenteral anticoagulant around interruption, whereas DOACs — with their rapid on/offset — are simply withheld for 24–48 hours (longer in renal impairment) without bridging. For bleeding: minor bleeds are managed with local measures and review of interacting drugs; major bleeding means stopping the agent and urgent referral, with reversal available — vitamin K plus prothrombin complex concentrate for warfarin, idarucizumab for dabigatran, and andexanet alfa (or PCC) for factor Xa inhibitors. Any fall on anticoagulation with head injury, black stools, or hematuria warrants immediate medical assessment.