Background: The Canadian Cardiovascular Society classification (CCSC) remains the standard for grading angina in patients with chronic stable angina. The utility value of this angina grading system in predicting the severity of coronary artery disease is not clear.
Aim: We studied the relationship between the clinical angina grade and the angiographic severity of underlying coronary artery disease.
Materials and methods: The participants in the study were 493 patients with stable angina who had undergone coronary angiography from 1998 to 2001. They were grouped according to their anginal grading and the number of vessels diseased. Significant lesions were defined as 50% narrowing for the left main and 70% for the left and right coronaries and their major branches.
Statistical analysis: The chi2-test was used for statistical analysis and a P-value <0.05 was taken as significant.
Results: There was no significant difference between the four angina class patients and the incidence of single-, double- and triple-vessel involvement. Class 1 patients had less left main trunk disease than class 4 patients. Class 3 and 4 patients had significantly fewer normal coronary angiograms.
Conclusions: There is generally little correlation between coronary artery disease and the CCSC of effort angina except for left main disease. Presence or absence of angina rather than the CCSC should indicate the need for coronary angiography.