Can you calculate the Mayo Clinic Risk Score (MCRS) for me?

Mayo Clinic Risk Score (MCRS) Calculation

The Mayo Clinic Risk Score (MCRS) is a validated tool that predicts in-hospital mortality following percutaneous coronary intervention (PCI) using seven simple clinical variables available before the procedure.

MCRS Calculation Formula

To calculate the MCRS, you need to add points for each of the following risk factors:

1. Age:

   • Add 1 point for each 5-year increment above 30 years
   • Example: 65 years = (65-30)/5 = 7 points

2. Cardiogenic shock:

   • Add 7 points if present

3. Renal failure (serum creatinine >2.5 mg/dL or on dialysis):

   • Add 3 points if present

4. NYHA class III-IV heart failure:

   • Add 3 points if present

5. Left main coronary artery disease:

   • Add 5 points if present

6. Multi-vessel coronary disease:

   • Add 2 points if present

7. Urgent/emergent procedure:

   • Add 2 points if procedure is urgent or emergent

8. Pre-procedure myocardial infarction ≤24 hours:

   • Add 2 points if present

Risk Stratification Based on MCRS

The total score corresponds to the following risk categories:

• Very low risk: MCRS < 5 (0% mortality)
• Low risk: MCRS 6-8 (0.9% mortality)
• Moderate risk: MCRS 9-11 (3.2% mortality)
• High risk: MCRS 12-14 (10.7% mortality)
• Very high risk: MCRS 15-25 (25.1% mortality)

Clinical Utility of MCRS

The MCRS has excellent discrimination for predicting in-hospital mortality following PCI with a c-statistic of 0.884 1. This makes it a valuable tool for:

1. Pre-procedure risk assessment: Provides evidence-based estimates of procedural risk before coronary angiography
2. Informed consent: Helps in discussing individualized risk with patients
3. Resource allocation: Identifies high-risk patients who may need more intensive monitoring

Validation and Performance

The MCRS has been externally validated in multiple large datasets:

• National Cardiovascular Data Registry (NCDR) with over 309,000 patients 1
• New York State PCI reporting system with 3,005 patients undergoing primary angioplasty 2
• Society of Thoracic Surgeons database with 370,793 patients undergoing CABG 3

While the MCRS was originally developed for PCI, it has shown moderate discriminatory ability (c-statistic = 0.715-0.784) in predicting outcomes after CABG surgery as well 3.

Important Considerations

• The MCRS should be calculated using pre-procedure variables only
• For primary PCI patients, all are considered to have intracoronary thrombus and undergoing urgent/emergent procedures 2
• The score performs well across various subgroups including gender, diabetes, renal failure, and different age groups 1

Limitations

• While excellent for PCI risk prediction, the MCRS performance is inferior to the Society of Thoracic Surgeons model when applied to CABG patients 3
• Some recalibration may be needed when applying the score to different populations 1

Remember that risk scores are tools to guide clinical decision-making but should not replace clinical judgment in individual patient care.