Inferior STEMI in cardiogenic shock with recent apixaban and a delayed catheter lab
A 58-year-old man with type 2 diabetes and permanent atrial fibrillation on apixaban 5 mg twice daily presents 9 hours after the onset of severe central chest pain. Blood pressure is 88/54 mmHg, pulse 118/min irregular, extremities cool, lactate 4.1 mmol/L, urine output 20 mL/h. ECG shows 3 mm ST elevation in II, III and aVF with reciprocal depression in I and aVL; right-sided leads have not been recorded. Troponin I is 42 ng/L (upper reference 14). Creatinine is 2.4 mg/dL (eGFR 32 mL/min/1.73 m²) and the last apixaban dose was 6 hours ago. Bedside echocardiography shows inferior wall hypokinesia, ejection fraction 40%, no pericardial effusion, and the right ventricle is inadequately seen. The catheterisation laboratory is functioning, but the on-call interventionalist is 70 minutes away; a spoke hospital 25 minutes away offers fibrinolysis. The patient is confused and only marginally cooperative.
1. Which reperfusion strategy would you choose, and how do the timing, the haemodynamics and the recent apixaban dose interact in that decision?
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Choose primary PCI; fibrinolysis is not a viable option here.
Three constraints converge on the same answer:
- Anticoagulant exposure. A DOAC taken 6 hours ago is a strong relative contraindication to fibrinolysis. Guidelines permit lysis only when the last DOAC dose was more than ~48 hours earlier with normal renal function. With eGFR 32 the apixaban effect is prolonged, so intracranial haemorrhage risk is unacceptable.
- Cardiogenic shock. Fibrinolysis has poor and unpredictable efficacy in low-output states (reduced absorption, low coronary flow, higher re-occlusion), and observational and trial data show clearly worse outcomes when lysis is used as the primary strategy in shock. Shock itself is an argument for mechanical reperfusion.
- Timing is still acceptable for PCI. The 70-minute interventionalist delay keeps first-medical-contact-to-device time within the ~120-minute threshold that justifies transfer for PCI; a 25-minute transfer to a spoke hospital for lysis buys a therapy you cannot safely give.
Practical plan: dual antiplatelet loading and parenteral anticoagulation immediately, resuscitate en route, and transfer directly to the PCI centre. If PCI became genuinely unavailable within the window, the correct alternative is urgent transfer or rescue lysis only after reversal/offset considerations - not immediate lysis at the spoke hospital.
2. Outline the antithrombotic regimen for PCI and the oral regimen afterwards. Does the creatinine of 2.4 mg/dL change the apixaban dose?
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Loading: aspirin 300 mg chewed plus a P2Y12 inhibitor. Because you plan triple therapy in a patient with a fresh DOAC load and high bleeding risk, clopidogrel 600 mg is the more defensible choice; ticagrelor 180 mg is acceptable only if the triple-therapy phase is kept to about a week.
Periprocedural anticoagulation: unfractionated heparin 70–100 U/kg IV bolus (no glycoprotein IIb/IIIa planned) is preferred over enoxaparin in shock with eGFR ~30, where enoxaparin dosing is awkward and accumulation unpredictable. Avoid fondaparinux, which is not a PCI anticoagulant. Radial access reduces access-site bleeding if the operator and haemodynamics allow.
Apixaban dosing - the trap: dose reduction to 2.5 mg twice daily requires two of three criteria: age ≥80 years, weight ≤60 kg, creatinine ≥1.5 mg/dL. This man meets only the creatinine criterion, so he should receive the full 5 mg twice daily dose. Reducing on a single criterion is a common error and leaves him under-anticoagulated for AF.
Long-term regimen: shortest possible triple therapy (1 week to 1 month, dictated by bleeding risk), then apixaban plus clopidogrel to 6–12 months, then apixaban alone. Add a proton pump inhibitor, avoid NSAIDs, and document a plan to reassess the HAS-BLED modifiable factors.
3. Two hours later he remains hypotensive at 84/50 mmHg despite 500 mL of crystalloid, and repeat ECG shows 2 mm ST elevation in V4R. Explain the mechanism and state how this changes your drug and device choices.
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Diagnosis: right ventricular infarction complicating inferior STEMI. V4R elevation with hypotension, clear lungs and raised JVP is the classic triad; the right ventricle is a volume-dependent, low-compliance chamber that fails when its free wall infarcts, so cardiac output becomes preload-dependent and the septum shifts.
What this changes:
- Withhold nitrates, diuretics and beta-blockers. Nitrates in RV infarction can precipitate profound hypotension by abolishing the preload the RV depends on. This is the single most examinable error in this scenario.
- Fluids are the first haemodynamic manoeuvre but only as small boluses (250–500 mL) with reassessment. He has already failed a 500 mL challenge and has an EF of 40%, so further blind fluid loading risks pulmonary oedema - switch to inotropes (dobutamine) for RV contractility plus norepinephrine to maintain coronary perfusion pressure (MAP ≥65 mmHg).
- Maintain sinus rhythm and avoid AV-nodal blocking drugs; RV ischaemia often produces bradyarrhythmias and AV block that worsen output - be ready to pace.
- Device choices: the lesion to treat is the right coronary artery, and reperfusion of the RV branch is therapeutic. An intra-aortic balloon pump does not support the right ventricle and should not be used for isolated RV failure; if refractory, consider ECMO or a right-sided mechanical support device in a centre that offers it.
- Echocardiography again to confirm RV dilatation and exclude a ventricular septal rupture or papillary muscle complication, and to exclude tamponade before escalating support.