Do indices of coronary conductance after reperfusion reflect the extent of salvaged myocardium?
Existing indices of coronary conductance (hyperemic flow-versus-pressure slope index, FPSI, and zero flow pressure, Pzf) have been developed as measures of microcoronary resistance. These indices, however, refer to cases of normal hearts, and there are no reports studying these indices following acute myocardial infarction. In this study, we investigated whether FPSI and Pzf truly measure the extent of myocardial salvage after successful reperfusion therapy. We also developed a new index of zero pressure flow, Fzp. Nineteen patients who underwent successful reperfusion therapy to the proximal portion of the left anterior descending artery (LAD) were studied. After successful reperfusion therapy, a Doppler wire was placed into the LAD. Aortic pressure was recorded in real time. Results from the aortic pressure and flow meter were combined to produce FPSI, Pzf, and Fzp. All cases underwent a resting thallium (Tl) and BMIPP scintigram within five days of successful reperfusion therapy. In
