Primary systemic amyloidosis is a multisystemic disorder secondary to a plasma cell dyscrasia. Dispenzieri et al developed a risk score for predicting survival in these patients, which can help stratify patients by risk and identify patients who may require more aggressive management. The authors are from the Mayo Clinic.
Parameters:
(1) serum cardiac troponin T in µg/L
(2) urine monoclonal (M) protein concentration in g per 24 hours
(3) age in years
(4) left ventricular ejection fraction
Parameter
Finding
Points
serum troponin T
<serum troponin>
urine M protein
<urine M protein>
age of the patient
< 65 years of age
<age in years>
>= 65 years of age
65
left ventricular ejection fraction
>= 55%
0
< 55%
1
R score =
= (3.19 * SQRT(serum troponin in µg/L)) + (0.52 * SQRT(urine M protein in g per day)) + (0.025 * (points for age)) + (0.34 * (points for left ventricular ejection fraction))
Interpretation:
• minimum R score in study: 0.77
• maximum R score: 5.2
• The higher the score the shorter the survival.
R Score
Median Survival
5 Year Survival
1
21.7 months
35%
2
15.8 months
15%
3
3.2 months
2%
4
1.4 months
0%
5
< 1 month
0%
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