The expected value of perfect information: cardiac catheterization after thrombolysis-is the value added greater than the cost?

To test the use of the concept of expected value of perfect information (EVPI), the role of catheterization after thrombolysis was addressed since this topic remains controversial. A decision tree was made to compare a strategy of catheterization to a strategy, of exercise testing followed by catheterization if the treadmill test was abnormal. The EVPI for both arms was similar at 0.95 years and represents the uncertainty in life expectancy between 1, 2, and 3 vessel disease. The catheterization arm cost an additional $232000 per year of life saved. In subtree analysis, the EVPI in the catheterization arm was 0.07 years, and increased to 0.13 years for an abnormal treadmill. If 1 life treadmill was normal, the EVPI was 0.01 years. If 1 life-year equals $35000 then one would be willing to spend only $300 to learn if he has 3 vessel disease after a normal treadmill test after thrombolysis