CLEVELAND, OHIO. Angioplasty (percutaneous coronary intervention) is a surgical technique used to free up blocked arteries. It is associated with a fairly significant mortality rate depending on the complexity of the blockage, the presence of unstable angina, and the use of stenting. Researchers at the Cleveland Clinic Foundation now report that the extent of active inflammation in the arteries at the time of surgery is an extremely important additional risk factor for death or heart attack within 30 days after angioplasty.
Their study involved 727 patients who underwent angioplasty between January and July 2000. The patients all had their level of C-reactive protein (CRP) measured prior to the procedure. CRP is a measure of systemic inflammation with higher levels indicating a more severe inflammation. The researchers found that patients with a CRP level greater than 1.01 mg/dL had 3.6 times greater risk of dying or having a heart attack within 30 days than did patients with a CRP level of less than 0.16 mg/dL. The actual rate of death or heart attack among patients with the lowest CRP level was 3.9 per cent as compared to 14.2 per cent for those with the highest level.
The adverse effect of active inflammation was even more pronounced in people with diabetes. Here those with the highest CRP had a 20.3 per cent risk of dying or having a heart attack within 30 days of undergoing angioplasty. The researchers have combined all the known risk factors associated with angioplasty (including CRP levels) into a mathematical model which is quite accurate in predicting the risk of dying or having a heart attack within 30 days of the procedure. The model predicts a death/heart attack rate of anywhere between 1 and 22 per cent depending on the risk factors.
Researchers at the University of Texas include their comments about the findings and suggest it may be desirable to postpone angioplasty in patients with high CRP levels until the underlying inflammation is under control.
Chew, Derek P., et al. Incremental prognostic value of elevated baseline C-reactive protein among established markers of risk in percutaneous coronary intervention. Circulation, Vol. 104, August 28, 2001, pp. 992-97
Yeh, Edward, T.H., et al. C-reactive protein: linking inflammation to cardiovascular complications. Circulation, Vol. 104, August 28, 2001, pp. 974-75 (editorial)