Purpose: We aimed to test for an early post-stress change in several hemodynamic parameters by impedance cardiography and its relation to the severity and extent of myocardial ischemia in patients undergoing exercise stress MPI.
Methods: We prospectively enrolled patients who were referred to the Nuclear Cardiology Center at the Sheba Medical Center for a clinically indicated exercise stress MPI study. All patients underwent testing using the NICaS before exercise and immediately after exercise. The differences between rest and stress hemodynamic parameters were compared with the severity and extent of myocardial ischemia by MPI.
Results: The study population included 198 patients; mean age was 62 years, 26% were women, 54% had hypertension, and 29% diabetes mellitus. 188 patients had =10% of ischemic myocardium and 10 patients had >10% of ischemic myocardium. In the first group, compared to rest, there was a significantly greater increase in post-exercise stroke index, stroke work index, cardiac index and cardiac power index (19.2%, 29.1%, 90.5% and 107%, respectively) when compared to the second group (-2.7%, 3.8%, 43.7% and 53.5%, respectively) as well as a significantly greater decrease in total peripheral resistance index (-38.7%) when compared to the second group (-16.3%), with corresponding p values of 0.015, 0.017, 0.040, 0.016, and <0.001, respectively.
Conclusions: Our data suggest that the immediate post-stress changes in several hemodynamic parameters as detected by the NIcAS can be used as an important adjunct to SPECT MPI for the early detection of myocardial ischemia.