Thorac Cardiovasc Surg 2016; 64 - OP242
DOI: 10.1055/s-0036-1571672

Digital Stethoskope System-VADoskope: A New Diagnostic Tool to Detect Thrombus Formation

E. Deniz 1, G. Röper 2, N. Reiss 3, S. Rojas Hernandez 1, S.-J. Hanke 1, S. Cebotari 1, J. Optenhöfel 1, M. Avsar 1, T. Schilling 1, A. Haverich 1, J.-D. Schmitto 1
  • 1Medizinische Hochschule Hannover, Hannover, Germany
  • 2Magdeburg, Germany
  • 3Schüchtermann-Schiller'sche Kliniken Bad Rothenfelde GmbH & Co.KG, Bad Rothenfelde, Germany

Objectives: Ventricular assist devices (LVAD) have become a standard in the treatment of heart failure. Nonetheless, some hurdles in LVAD surgery remain, such as complications due to thrombus formation, which could lead to stroke, reoperation or death. The high hospitalization costs must also be addressed.Currently CT, Echo and VAD parameters as well as hemolysis signs are the only available tools for thrombus formation in VADs. The aim of this study was to test a novel diagnostic tool to detect thrombosis in VAD.

Methods: In-vivo evaluation of acoustic signals is performed with a novel device called digital stethoscope system-VADoskope. We performed an analysis of 7 VAD patients (HVAD, Heartware) who had signs of suspected thrombus formation in the VAD (group A) and compared the results of 7 patients who were free from thrombosis (group B). For each patient, the acoustic signal (Hz,dB,harmonics,spectral lines), pump-speed (rpm), power consumption (watts), flow (L/min), laboratory as well as clinical or apparative thrombus-signs were recorded.

Results: Baseline characteristics of group A and group B are presented in Table 1. In the case of a clean referenz-spektogram, that means no thrombus is inside, the fundamental frequency is f1 = ∼ 50Hz (depending on the adjusted pump speed), Due to the construction of HVAD (impeller with four “wings”) the detectable spectral line in a clean HVAD is f2 = 4f1 and the 1. harmonic is visible. Additionally, the number of disk hitting the pump house is < 4 and the recorded dB scale between (-)20 and (-) 60. This characteristics were found in all patients of group B. In comparison to group B, all patients of group A presented additional spectral lines. Also, the second and / or third harmonics, and their multiples were visible which are not visible during normal function as well as significant higher (P <  0.005) dB and number of disk hitting the pump housing were detected in group A.

Conclusions: This study present that the Digital Stethoscope System-VADoskope is able to detect thrombus formation in VAD.Our results indicate that acoustic monitoring might become a useful future tool for next generation VADs.

Table 1 Baseline characteristics