LIMITATIONS
While we attempted to obtain imaging on all patients, 7% lacked CTs.
Patients implanted urgently may not have preoperative imaging, while
patients who expire or are transplanted during the index hospitalization
may not have postoperative CTs. We also did not serially assess IFC
position at pre-specified intervals. Follow-up scans were only obtained
if patients had pump-related complications potentially related tode novo or worsening malposition. Shih13 found
no major change in Heartmate 3 pump-spine angle on x-ray during 12-month
follow-up.
We also did not assess LV unloading using invasive hemodynamics. Our
center does not routinely obtain these studies outside of the initial
hospitalization. We used LVAD FI as a surrogate for cardiac output, but
did not have a similar measure for LV filling pressures. We also did not
have serial echoes at pre-specified time points, and instead used two
broad intervals: early (1-3 months post-LVAD) and late (6-12 months).
Finally, while the population studied (N = 114) is one of the largest
malposition series presented, these are single-center, single-device
data covering a ten-year timespan. We chose to only include the HVAD in
this series because we had extensive experience with and a
well-established surgical protocol for that device. During the study
period, only six Heartmate 3 patients met criteria, and we were still in
the learning stages of using the LTHS technique for it. However, both
pumps have similar profiles and similar-size integral IFCs so there is
no reason to think our results would not apply to that device as well.