What is the best management approach for a patient with a history of MI, metastatic prostate cancer, sleep apnea, AAA, and recent central chest pain, who has impaired renal function, recent urosepsis, and an elevated D-Dimer?

Management of Acute Chest Pain in a Patient with Complex Comorbidities and Renal Impairment

The most appropriate management for this 73-year-old male with recent central chest pain, history of MI, metastatic prostate cancer, and severe renal impairment requires urgent cardiology consultation and consideration for a V/Q scan rather than CTPA due to his significantly impaired renal function (eGFR 16).

Clinical Assessment and Risk Stratification

This patient presents with several concerning features:

• Sudden onset central chest pain at rest, described as heavy pressure
• Pain unrelieved by GTN spray and aspirin
• Associated symptoms of sweating and dizziness
• Duration of 1.5 hours
• Pain worse on inspiration
• Significant cardiovascular risk factors: previous MI with stents, AAA, sleep apnea
• Metastatic prostate cancer
• Severe renal impairment (creatinine 318 μmol/L, eGFR 16 mL/min)
• Elevated D-dimer (523)

Differential Diagnosis

1. Acute Coronary Syndrome (ACS)

   • Serial troponins are reassuring (5.7 → 6.7 ng/L, well below the cutoff of 53 ng/L)
   • ECG shows known RBBB without new changes
   • Pain characteristics somewhat atypical (worse on inspiration)

2. Pulmonary Embolism (PE)

   • Elevated D-dimer (523)
   • Pain worse on inspiration
   • Low Wells score (1)

3. Pericarditis

   • Recent urosepsis
   • Pain worse on inspiration
   • Not improved with position changes

4. Aortic pathology (dissection/aneurysm)

   • Known AAA
   • Sudden onset severe chest pain

Management Approach

Immediate Management

1. Renal Function Management 1

   • The patient has severe renal impairment (eGFR 16 mL/min, Stage 4 CKD)
   • This represents acute kidney injury (AKI stage 1) from baseline creatinine of 178 (eGFR 33)
   • Careful IV hydration with isotonic saline
   • Monitor fluid status closely to avoid volume overload
   • Target urine output of 100-150 mL/hour

2. Diagnostic Workup for PE

   • Despite low Wells score, elevated D-dimer requires further investigation
   • V/Q scan is the appropriate choice rather than CTPA due to severe renal impairment
   • D-dimer has high sensitivity but decreased specificity in renal impairment 2, 3
   • The scheduled V/Q scan is appropriate to avoid contrast-induced nephropathy

3. Cardiac Assessment

   • Serial troponins have been reassuring
   • Cardiology consultation has already been obtained
   • ECG monitoring for any dynamic changes

Special Considerations for Renal Impairment

• Medication Adjustments 1

  • Adjust all medication doses according to eGFR of 16 mL/min
  • Avoid nephrotoxic medications
  • Use caution with anticoagulants if needed

• Contrast Studies 4, 1

  • Avoid iodinated contrast if possible
  • If contrast is absolutely necessary:
    • Use iso-osmolar contrast agents
    • Limit contrast volume based on formula: Maximum contrast volume = 5 mL × body weight (kg)/serum creatinine (mg/dL)
    • Ensure adequate hydration before and after procedure

• Nephrology Consultation 1

  • Indicated due to eGFR <30 mL/min with acute decline from baseline
  • May need to consider renal replacement therapy if further deterioration occurs

Follow-up and Ongoing Management

1. Cardiovascular Risk Management 4, 1

   • Continue appropriate secondary prevention medications adjusted for renal function
   • Ensure optimal management of sleep apnea with CPAP
   • Blood pressure control with appropriate agents

2. Renal Function Monitoring 1

   • Daily monitoring of renal function
   • Careful fluid balance assessment
   • Avoid further nephrotoxic insults

3. Cancer Management Considerations

   • Coordinate with oncology regarding management of metastatic prostate cancer
   • Recent axillary lymph node evaluation showed no evidence of metastases

Potential Pitfalls and Caveats

1. D-dimer Interpretation in Renal Impairment

   • D-dimer levels are often elevated in patients with renal impairment regardless of PE status 2, 3
   • Standard D-dimer cutoffs have lower specificity in renal impairment
   • Do not exclude PE based solely on marginally elevated D-dimer in this population

2. Contrast-Induced Nephropathy Risk

   • This patient is at extremely high risk for contrast-induced nephropathy with eGFR 16 mL/min 4, 5
   • Avoid iodinated contrast if possible; V/Q scan is preferred over CTPA

3. Troponin Interpretation

   • Troponin levels may be chronically elevated in patients with renal impairment
   • Serial measurements showing minimal change are reassuring

4. Medication Management

   • Careful dose adjustment of all medications based on renal function
   • Consider nephrology consultation for medication management

This patient requires a careful balance between diagnostic thoroughness and avoiding further renal injury. The scheduled V/Q scan is appropriate, and continued monitoring of both cardiac and renal status is essential.