Discussion:
After disappointing results of intra-aortic balloon pumping1-3, va-ECMO has been the preferred option of the
mechanical circulatory support for sustained CS. However, va-ECMO does
not unload LV, and by increasing the afterload, it may lead to LV
congestion, pulmonary edema, and secondary right heart failure.
Recently, Impella (2.5, CP, and 5.0) has evolved as another valid
catheter-guided mechanical circulatory device for left heart failure.
Impella can produce antegrade flow and additionally unload LV, i.e.,
reduce myocardial oxygen demand and increase the coronary circulation4-7.
Back to this case, a sequential combination of different systems allowed
for successful step-wise recovery of a patient initially at a very
marginal state with sustained biventricular failure. Impella CP saved
the patient in primary low-output and served as a
bridge-to-revascularization. Termination of the heart-lung machine was
only possible after implantation of va-ECMO. With no sign of relevant LV
recovery on 7th POD, Impella 5.0 was implanted to
terminate va-ECMO, and the Impella was inserted through the femoral
artery as the axillar access was impractical. Retrospectively, we
speculate that 1) either the prosthesis was sewn in a region not
allowing flexible manipulation and introduction of the big caliber of
Impella 5.0 (the pump size is max. 21 Fr; or 2) due to a vertical angle
between the prosthesis and the artery (ideally 45 to 60 degree); or 3)
due to additional borderline diameter of the axillary artery. In a
retrospective view, both the inadequate flow of Impella 5.0 and the
impossibility of va-ECMO weaning were most likely consequences of RV
dysfunction. Actually, Impella 5.0 delivered 5.0 L/min flow after
implantation of TandemHeart ProtekDuo. TandemHeart ProtekDuo is a
percutaneous device for RV support and a valid alternative to surgically
implanted RV assisted device, avoiding additional operative steps. In
our opinion, a stepwise strategy and adaptive weaning pattern with
switch from va-ECMO to Impella 5.0 for the LV support with implantation
of TandemHeart ProtekDuo for the RV support and consecutive weaning of
either univentricular support under differentiated pharmacological
conditioning and close TEE monitoring is a favorable approach for
successful stabilization of critically unstable patients in CS such as
in the present case.