STEMI reperfusion — structured written assessment

SAQ 1 (10 marks)

Practice scenario. A 64-year-old man weighing 72 kg arrives at a rural hospital without a catheterisation laboratory 90 minutes after chest pain began. The ECG shows new 3 mm J-point ST elevation in II, III and aVF. The retrieval service estimates that wire crossing at the nearest PCI centre would be about 150 minutes after this ECG. He has no contraindication to fibrinolysis.^[1][2]

1. State the ST-elevation criteria he meets under the 2023 ESC ACS guideline. (2) ^[1]
2. State the primary PCI time limits in the 2023 ESC and 2025 ACC/AHA guidelines, and choose his reperfusion strategy. (3) ^[1][2]
3. Write the fibrinolytic and adjunctive antithrombotic prescription using the 2025 ACC/AHA dose tables. (3) ^[2]
4. Outline what happens after the bolus, with one supporting trial. (2) ^[1][5]

Model answers

1. New J-point ST elevation in at least two contiguous leads, 1 mm or more in leads other than V2–V3, in the absence of LV hypertrophy or LBBB. He has 3 mm in three inferior leads.^[1]
2. ESC 2023: a primary PCI strategy is recommended over fibrinolysis if the anticipated time from diagnosis to PCI is under 120 min (Class I, Level A). If not feasible, give immediate fibrinolysis and transfer without waiting for signs of reperfusion.^[1] ACC/AHA 2025: primary PCI if FMC-to-first-device is 90 minutes or less, or 120 minutes or less in transfer patients. At a non-PCI-capable hospital, transfer for primary PCI is recommended if device activation can reasonably be predicted within 2 hours of FMC; if not, and symptoms began under 12 hours ago, fibrinolytic therapy is recommended.^[2] His expected time exceeds 120 min and he is within 12 h, so he should have fibrinolysis now. ESC 2023 aims to start it within 10 min of diagnosis.^[1]
3. Tenecteplase: single IV weight-based bolus, 40 mg for 70–79 kg. Aspirin loading 162–325 mg orally, chewed when possible. Clopidogrel 300 mg loading dose (age 75 or younger). Enoxaparin (age under 75): 30 mg IV bolus, then 1 mg/kg SC every 12 h starting 15 min later, maximum 100 mg for the first 2 doses.^[2] ESC 2023 names weight-adjusted tenecteplase, low-dose aspirin, oral clopidogrel and enoxaparin as the most extensively studied pharmaco-invasive regimen.^[1]
4. Transfer to the PCI centre immediately after starting lysis. Rescue PCI if ST resolution is under 50% within 60–90 min, or with haemodynamic or electrical instability, worsening ischaemia or persistent chest pain. Otherwise routine angiography within 2–24 h.^[1] In STREAM (patients with STEMI within 3 h of symptom onset who could not have primary PCI within 1 hour), prehospital tenecteplase then angiography gave a similar 30-day composite to primary PCI: 12.4% vs 14.3% (RR 0.86, 95% CI 0.68–1.09; P=0.21).^[5][1]

SAQ 2 (10 marks)

Practice scenario. Seventy-five minutes after tenecteplase, the man in SAQ 1 still has chest pain. ST elevation has resolved by 40%. His BP is 84/56 mmHg, his lungs are clear and his JVP is raised.^[1][30]

1. Give the ESC 2023 criterion for failed fibrinolysis and the ACC/AHA 2025 signs that can indicate failed reperfusion, and the next step, with trial evidence. (4) ^[1][2][7]
2. Name the complication suggested by his haemodynamics, the ECG leads you would record, and the immediate treatment. (3) ^[30]
3. On day 3 after PCI he becomes suddenly hypotensive with a new systolic murmur. Give your approach. (3) ^[1][2]

Model answers

1. ESC 2023: ST resolution under 50% within 60–90 min, or haemodynamic or electrical instability, worsening ischaemia or persistent chest pain, indicates rescue PCI. Repeat lysis is discouraged.^[1] ACC/AHA 2025 lists signs that can indicate incomplete reperfusion: under 50% resolution in anterior leads or under 70% in inferior leads, lack of symptom improvement, or instability. Failed reperfusion means immediate angiography and rescue PCI.^[2] REACT (patients with STEMI in whom reperfusion failed, with less than 50% ST resolution within 90 minutes after thrombolysis): event-free survival at 6 months was 84.6% with rescue PCI, 70.1% with conservative care and 68.7% with repeat thrombolysis.^[7]
2. Right-ventricular infarction, which complicates about 25% of inferior infarcts. LV filling then depends on preload, and nitroglycerin and morphine may worsen hypotension.^[30] Record V3R and V4R; ST elevation there is highly suggestive of RV ischaemia (ESC 2023).^[1] Give IV fluid to support preload, use vasodilators judiciously, and avoid nitrates.^[30][1]
3. Sudden hypotension and a new murmur suggest a mechanical complication (acute mitral regurgitation from papillary muscle rupture, or ventricular septal defect).^[1][32] ESC 2023: immediate echocardiographic assessment is indicated when mechanical complications are suspected.^[1] ACC/AHA 2025 recommends a Heart Team approach as soon as a mechanical complication is diagnosed.^[2] ESC 2023 says IABP should be considered with haemodynamic instability or shock due to a mechanical complication (Class IIa, Level C); ACC/AHA 2025 says MCS devices can be considered as a bridge to surgery when clinical stabilisation is required, although randomised data are lacking.^[1][2] Both guidelines regard surgery as the treatment of choice.^[1][2] In-hospital mortality after STEMI mechanical complications was 42.4% in the National Inpatient Sample (2003 to September 2015).^[31]