Suspected pulmonary embolism in advanced chronic kidney disease

Wells score. PE more likely than an alternative diagnosis = 3; heart rate >100 = 1.5; no clinical signs of DVT, no immobilisation or surgery, no previous VTE, no haemoptysis, no active malignancy → 4.5, i.e. 'PE likely'.

D-dimer. It is uninterpretable here for decision-making. Age-adjusted cut-off (58 × 10 = 580 µg/L) is exceeded and, more importantly, above a Wells score of 4 a negative D-dimer cannot safely exclude PE. He needs imaging whatever the D-dimer.

Imaging. CTPA remains the investigation of choice: it is sensitive, specific and gives alternative diagnoses. An eGFR of 19 is a relative, not absolute, contraindication - the risk of contrast-associated nephropathy is far smaller than the risk of missing a potentially fatal PE. Mitigate by using the lowest contrast volume, pre- and post-hydration with isotonic saline, and withholding nephrotoxins. If CT cannot be done promptly, V/Q SPECT today is a reasonable alternative (no iodinated contrast, good sensitivity when reported as a SPECT study), accepting a higher chance of a non-diagnostic scan, in which case CTPA follows. What must not happen is a 24-hour delay in diagnosis with no treatment.

Yes - start therapeutic anticoagulation immediately, provided there is no bleeding contraindication, because imaging may be delayed and clinical probability is high.

Renal calculation. Cockcroft–Gault: (140−58) × 82 / (0.815 × 300) ≈ 27 mL/min.

Options.

• Unfractionated heparin by weight-adjusted intravenous infusion with APTT or anti-Xa monitoring is the safest first choice: it does not accumulate in renal failure and is rapidly reversible if he needs thrombolysis or a procedure. It also avoids subcutaneous accumulation before you know whether renal function is stable or worsening.
• Enoxaparin 1 mg/kg once daily (82 mg) is an accepted reduced regimen at this creatinine clearance; the standard 1 mg/kg twice daily dose accumulates and causes major bleeding in severe renal impairment.
• Avoid fondaparinux (contraindicated below 30 mL/min), and avoid starting a DOAC acutely in an unstable patient with creatinine clearance under 30 who may need thrombolysis.

Give the first dose before he leaves the department, and document a plan for the result - do not leave anticoagulation contingent on the scan.

This is high-risk (massive) PE with haemodynamic instability - an indication for reperfusion, not for more investigation.

Immediate steps.

1. Call for senior and critical-care help; give oxygen, continuous monitoring, and a cautious fluid challenge (250–500 mL crystalloid) rather than large volumes, which can worsen right ventricular failure.
2. Systemic thrombolysis: alteplase 10 mg IV bolus then 90 mg over 2 hours (or weight-banded tenecteplase as a single bolus). Stop the heparin infusion during thrombolysis, then restart when APTT is <2× normal.
3. Screen for absolute contraindications (recent intracranial surgery or haemorrhage, active bleeding, recent ischaemic stroke) - if present, escalate to catheter-directed therapy or surgical embolectomy rather than abandoning reperfusion.
4. If he arrests, prolonged CPR with rescue thrombolysis is appropriate; consider extracorporeal support in a centre that offers it.

After stabilisation. Confirm the diagnosis with bedside echo (right ventricular dilatation, impaired function) and complete imaging when safe; then continue anticoagulation for at least three months, review whether the long-haul flight plus obesity represent transient risk factors, and involve nephrology about his renal trajectory.