Technical Considerations and Discussion:
We report three cases of Micra implantation following 52mm EVOQUE TTVR.
Based on our experience, MICRA leadless pacemaker following EVOQUE TTVR
is feasible via either a femoral or jugular venous approach, though the
jugular approach tends to force the Micra to the apex, an undesirable
position. The primary technical consideration during MICRA delivery was
atraumatic placement of the delivery sheath across the valve prosthesis.
Multiple fluoroscopic views were used. The MICRA delivery catheter was
directed toward the ventricle in a right anterior oblique view (RAO),
prior to advancing the system across the valve. A steep left anterior
oblique (LAO) view (typically greater or equal to 45 degrees) providing
an appropriate oblique angle for alignment of the delivery catheter with
the lumen of the EVOQUE TTVR centrally was then obtained (See figure 1
b). We then utilized an RAO view to advance the MICRA delivery system to
the interventricular septum in a position where it would not interact
with the ventricular anchors of the EVOQUE TTVR (See figure 1c and
supplemental videos). During the first two cases there was significant
interaction between the tether and the valve prosthesis (See figure 1d).
Due to this experience, in the third case the delivery cone was not
retracted beyond the valve prosthesis, which resolved the issue. Early
experience placing leadless pacemakers across recently implanted
surgical bioprosthetic tricuspid valves suggested similar fluoroscopic
approaches[17]. MICRA implant for each of the patients in our case
series was completed while the patient was on full dose anti-coagulation
without any significant bleeding complications recognized. The
procedural time from vessel puncture to closure was short (14 minutes)
for the two cases that were accomplished from the femoral vein. The case
that involved switching to a jugular approach obviously took longer (54
minutes). Electrical data for each of the devices implanted was
excellent, with a predicted device longevity of at least 7 years with a
100% pacing burden. In one case Micra AV was utilized and, at least
early after implant, AV synchrony was achieved.
The use of percutaneous tricuspid valve interventions is predicted to
grow significantly in the coming years as there continues to be no class
I indication for surgical treatment of isolated TR[1-3]. Conduction
system abnormalities post-TTVR will continue to be an important
consideration for patients[6]. Given the lack of short-term or
long-term data regarding pacemaker leads across TTVR implants, leadless
pacemakers may offer an ideal solution for pacing support in this
population by preventing interaction with the valve leaflets and
structure. Additionally, given the usual age, frailty, and
co-morbidities of patients undergoing TTVR, reducing infection risk is a
primary concern and may be further reduced with leadless pacing[15].