Computerized tabulation of cine coronary angiograms. Its implication for results of randomized trials.

Abstract

The quality of cine angiography is excellent in our days, and as a consequence some of the pitfalls encountered in previous randomized trials are not currently present. An example can be found in the CASS analysis of the reproducibility of coronary arteriographic reading by the Quality Control Committee Sessions: "There is an indication that different clinics" involved in the CASS trial "can reduce the variability between their readings by concerted effort to improve both the quality and the completeness of the angiographic examination." The introduction of electronic calipers to judge the severity of the obstruction can eliminate human errors. The computerized protocol has the disadvantage that it takes longer to tabulate cine coronary angiography and it will depend on its pattern, but it certainly will not be as long as filling in the CASS protocol. However, this effort is justified because it will enrich our knowledge of coronary arteriosclerosis. As a result, patients will be divided into proximal (1, 2, 12, 13, and 19), middle (mainly, 3, 14, and 20), and distal (remainder) segments. Sometimes midsegments can be important. For example, in the report from CASS related to the left main equivalent lesions, the 5-year survival rate was 48% if the obstruction on the left anterior descending was proximal and increased to 71% if it was more distal. Several randomized studies to compare PTCA with CABG as suggested by Gruentzig et al in 1979 are underway, and it is hoped that the data will be properly analyzed. However, if cine coronary angiography and the status of the left ventricle are not carefully tabulated (classification of patients into left main trunk or one-, two-, or three-vessel disease is not sufficient), the results of the randomized trials comparing PTCA with CABG will add more confusion instead of clarifying proper therapeutic implications.