Periprocedural Doppler coronary blood flow predictors of myocardial perfusion abnormalities and cardiac events after successful coronary interventions

From research to clinical practice: current role of intracoronary physiologically based decision making in the cardiac catheterization laboratory

Decisions regarding coronary interventions should be combined with objective evidence of myocardial ischemia. The most common physiologic approach utilizes hospital facilities outside the catheterization laboratory, requiring additional time and cost. With the introduction of sensor-tipped angioplasty guide wires, distal coronary flow velocity and pressure can be obtained in the cardiac catheterization laboratory, facilitating physiologically based decisions regarding the need for intervention. In the catheterization laboratory, physiologically significant stenoses can be characterized as having impaired post-stenotic coronary flow reserve < 2.0 and pressure-derived fractional flow reserve < 0.75, both variables related strongly to positive ischemic perfusion imaging or stress testing results. Deferring coronary interventions on the basis of normal translesional physiology is safe and is associated with a low rate (< 10%) of lesion progression over a 10-month follow-up period. Preliminary data indicate that excellent physiologic and anatomic end points after balloon angioplasty are associated with low (< 20%) restenosis rates at 6-month follow-up. Clinically relevant relations of in-laboratory physiology support the insight that physiologic, as much as or more than anatomic variables, ultimately determine the functional status of a patient. Current data suggest that an intracoronary physiologic approach complements coronary lumenology and appears to have important clinical and economic implications for patients undergoing invasive evaluation and treatment of coronary artery disease.

Practical coronary physiology. Clinical application of the Doppler flow velocity guide wire

Coronary angiography incompletely delineates the physiologic consequences of many epicardial stenoses. Intracoronary translesional flow velocity measurements using the Doppler flow wire during cardiac catheterization provide immediate data discriminating the physiologic significance of coronary stenoses. The validity and accuracy of the flow wire for analyzing lesion hemodynamic significance have been confirmed in multiple studies. Flow velocity analysis provides objective criteria for refining the selection of cases for revascularization, and prospective clinical data have confirmed the safety of deferring intervention on lesions with normal physiologic assessment. Translesional and distal coronary flow velocity dynamics during procedures also provide immediate data assessing the physiologic adequacy of intervention. Impaired postintervention distal coronary flow velocity and vasodilator reserve can predict subsequent clinical events, and comparisons of flow velocity indices prestenting and poststenting suggest that physiologically inadequate results of angioplasty may be improved by additional intervention. Flow velocity assessment may also have utility in profiling the adequacy of infarct artery reperfusion following acute myocardial infarction. Evidence has been accumulated to support use of Doppler flow velocity analysis as a clinically relevant technique for improving both diagnostic and therapeutic aspects of cardiovascular medicine.