Validation of Non-Invasive RAMP-Testing for HeartMate 3

Abstract

RAMP-testing in the postoperative period can be used to optimize LVAD speed for optimal left ventricular unloading, cardiac output, right ventricular function, and LV-RV interactions. We tested the hypotheses that a non-invasive echocardiographic RAMP-test post HM3 implantation improves LV unloading immediately after and 1-3 months after as compared to before the test. We also tested a secondary hypothesis that RPM adjustments during echocardiography-guided RAMP-testing does not worsen RV function immediately after and 1-3 months after. We retrospectively reviewed data from patients followed at our Hospital after HM3 implantation between 2017 and 2019, who had gone through an echocardiographic RAMP-test. A total of 14 out of 19 patients were clinically stable and were enrolled. LVAD speed was increased in 100 RPM increments at 1-minute intervals and echocardiographic images were acquired at every step. Adequate LV unloading was defined as no more than mild mitral regurgitation (MR), and intermittent aortic valve (AV) opening or closed AV, and reduction of LVEDD; and for the follow up measurement, decreased NT-proBNP. Median (IQR) time from implantation to RAMP-test was 27 (16-56) days and median time from RAMP-test to follow up echocardiography was 55 (47-102) days. Median pre-RAMP LVAD speed was 4950 (4875-5225) RPM. Median LVAD speed achieved during RAMP-testing was 5550 (5375;6025) RPM, which was significantly higher than pre-RAMP LVAD speed (p=0.001), and median final LVAD speed was 5200 (5000-5425) RPM, which was also significantly higher than pre-RAMP LVAD speed (p=0.003). RAMP-testing resulted in final LVAD speed increase in 11 (79%) patients and a median net change of 200 (200-300) RPM. Speed adjustments after RAMP-testing resulted in optimized final LVAD speed, manifested as improved LVAD unloading that was achieved in 3 (21%) patients who were not originally optimized. RV function did not worsen significantly during RAMP-testing or at final LVAD speed. Echocardiography-guided RAMP-test allowed LVAD speed adjustment and optimization, and improved LV unloading during RAMP-testing and at final speed with no evidence of worsening of RV function. This study adds to the evidence of echocardiographic RAMP-test as an established, non-invasive and safe technique for speed optimization in HM3 patients.