Methods for the assessment of PTCA success

Numerous criteria for the assessment of the immediate and late results of percutaneous transluminal coronary angioplasty (PTCA) are currently in use. Here, the values and limitations of the transstenotic gradient (TG), visual qualitative angiogram assessment, quantitative coronary angiography and the coronary flow reserve (CFR) will be discussed. Although measurement of the TG may be clinically useful, current data suggest that it does not accurately reflect the "true" pressure-flow-resistance across coronary lesions. Furthermore, the widely applied method of visual interpretation of coronary angiograms is hampered by several serious shortcomings: large intra- and interobserver variabilities, and lack of correlation with pathologic as well as intraoperative findings. In contradistinction, CFR and minimal luminal cross-sectional area (MLCA) appear to be more reliable parameters for judging the physiologic importance of (residual) coronary obstructions. In fact, given the curvilinear relation between CFR and MLCA (r = 0.92), the available evidence suggests that at the moment quantitative coronary angiography--with measurement of the MLCA immediately after PTCA--is the method of choice in assessing the efficacy of coronary angioplasty.