Abstract 515 Accuracy of shear wave elastography in detection of limb perfusion deficits in ICU patients with VA-ECMO and antegrade limb perfusion- a pilot study

Clin Res Cardiol (2023). https://doi.org/10.1007/s00392-023-02180-w
Accuracy of shear wave elastography in detection of limb perfusion deficits in ICU patients with VA-ECMO and antegrade limb perfusion- a pilot study
M. Maslarska¹, S. Piepenburg¹, A. Supady², C. Hehrlein¹
¹Innere Medizin III, Kardiologie und Angiologie, Universitäts-Herzzentrum Freiburg - Bad Krozingen, Freiburg im Breisgau; ²Interdisziplinäre Internistische Intensivmedizin (IMIT), Universitäts-Herzzentrum Freiburg - Bad Krozingen, Freiburg im Breisgau;
Background: Patients with VA-ECMO often suffer from ischemia at the cannulated leg, which is associated with a higher mortality. Near-infrared spectroscopy (NIRS) is currently the only method for continuous monitoring of oxygen saturation and indirect parameter for blood perfusion deficits in the subcutaneous connective tissue of the lower limbs. In this way, shear wave elastography (SWE) presents a novel, sensitive and non-invasive ultrasound method in the diagnosis of ischemia related muscle contraction deficits. Purpose: In this explorative, first-in-men study we analysed whether shear wave elastography during passive stretch of the peripheral lower limb muscles is a sensitive ultrasound method that could improve detection of early limb ischemia during VA-ECMO with or without antegrade limb perfusion. Methods: Eleven intensive care unit patients with VA-ECMO were included in this pilot study. All patients recovered from a cardiac arrest due to myocardial infarction, rhythm abnormalities or respiratory failure. Seven patients obtained antegrade limb perfusion during or after implantation of the VA-ECMO. Both lower limbs and the head in all patients were monitored with NIRS. We performed an ultrasound examination of the medial gastrocnemius muscle as a region of interest (ROI) using shear wave elastography at resting state and during passive stretch. The latter was achieved via maximal dorsal flexion of the foot assisted by the same examiner in all cases. Furthermore, we also performed a color-coded duplexsonography assessing blood flow velocity of the peripheral arteries in these patients. Results: We found a significant difference in muscle SWE-values during stretch between the cannulated (58.9 ±13.5 kPa) and cannula-free limb (95.7 ±27.9 kPa: p< 0.001). No significant SWE difference between both limbs was detected at a resting state of the muscle. Moreover, there was no correlation between NIRS measurements and SWE values (kPa) of both lower limbs depicted by ANOVA testing and linear regression analysis. However, we observed a strong correlation between the blood flow level generated by the VA-ECMO and our peripheral SWE measurements. Our results support the hypothesis that SWE offers a more sensitive evaluation and monitoring of peripheral muscle function at early stages of ischemia compared to NIRS. Conclusion: SWE is an easy to apply ultrasound technique providing early information about ischemia related muscle contractility loss and ongoing limb ischemia in VA-ECMO patients. This novel method might be helpful being more accurate than NIRS in detecting ischemic muscle contractility deficits caused by reduced lower limb blood flow due to the arterial ECMO cannulation. Larger trials are needed to confirm these early results of our pilot study.
https://dgk.org/kongress_programme/jt2023/aP1717.html