Abstract 3665: Coronary Microvascular Resistance Estimated by a Novel Dual-Sensor (Pressure and Doppler Velocity) Guidewire Reflects Myocardial Viability After Acute Myocardial Infarction
[Background] A novel dual-sensor (pressure and Doppler velocity) guidewire has an ability to estimate coronary microvascular resistance. Coronary micro-circulation might be damaged as well as myocardiual damage in AMI. The aim of this study was to evaluate the possibility of the dual-sensor guidewire for predicting myocardial viability after AMI.
[Methods and Results] We enrolled 20 patients (AMI; n=10, angina pectoris (AP); n=10) with a culprit lesion in the left anterior descending coronary artery. A novel 0.014-inch dual-sensor guidewire was placed distal to the lesion to take per-beat averages of pressure and flow velocity simultaneously. Apparent microvascular resistance (MVR) index calculated as a mean pressure divided by averaged peak flow velocity were obtained during maximal hyperemia. At the same time, the peak flow velocity was plotted against the coronary pressure, and the pressure at zero flow (Pzf) was calculated from the slope of the flow-pressure relation in the phase of diastolic flow decrease. Furthermore wall motion score (WMS; normal=1 to dyskinesia=5) indexes were calculated by dobtamine stress echocardiography for the assessment of myocardial viability after successful percutaneous coronary intervention (PCI). The average duration from the onset of symptom to the evaluation of coronary micro-circulation was 4.4 +/- 1.5 hours in AMI. There were no complications caused by procedure. In all patients, MVR index was significantly correlated with Pzf (r=0.92, p<0.01). Before the PCI, MVR index (4.8 +/- 2.1 vs. 1.2 +/- 0.4, p<0.05) and Pzf (54 +/- 31 vs. 11 +/- 5 mmHg, p<0.05) in patients with AMI were significantly higher than those in patients with AP respectively, and they were not changed after executed PCI. MVR index (r=0.89, p<0.01) and Pzf (r=0.87, p<0.01) were correlated with WMS indexes calculated by dobtamine stress echocardiography. In the cases with MVR index >6.0 or Pzf > 80mmHg, the recovery of the wall motion in the infracted area by dobtamine stress echocardiography did not observed.
[Conclusion] A novel dual-sensor guidewire is feasibile and safe to evaluate the damage of coronary micro-circulation, and MVR index and Pzf are useful predictors for myocardial viability in patients with AMI.