Speaking during an innovation session at TVT 2019 (12-15 June, Chicago, USA), Mark Hensey (Centre for Heart Valve Innovation, St Paul’s Hospital, University of British Columbia, Vancouver, Canada) outlined the early experience with a purpose-designed temporary pacing guidewire (Wattson, Teleflex). He said the wire delivered “safe and effective pacing” for both aortic and tricuspid positions.
Hensey reported that a temporary transvenous pacemaker (TVP) is “commonly utilised to allow burst and back-up pacing” during transcatheter heart valve procedures. However, he said that TVP placement is “not without risks”–commenting that it can lead to vascular injury, bleeding and thrombosis among other complications. “Tricuspid valve-in-valve procedures, in particular, offer challenges because traditional placement of the wire in the right ventricle is not possible and you have to look at other options, such as the left ventricle or the coronary sinus,” Hensey commented.
He added that studies have demonstrated that a guidewire placed in the left ventricle could be used to provide unipolar pacing during transcatheter heart valve procedures but that this was also not without problems. Hensey explained that it “requires modification of the wire and technical expertise” and unipolar pacing “results in high thresholds and, potentially, loss of capture”. “If there is a need for back-up pacing, you cannot pace without the delivery system in place,” he added.
Therefore, the Wattson temporary pacing guidewire was developed. The wire is 0.035 inches in diameter and 280cm in length, with Hensey noting it was slightly than longer than standard guidewires to allow removal of the transcatheter heart valve system if pacing was required post deployment. The guidewire also has multiple exposed electrodes to allow consistent capture, connects to a standard external pacemaker, and provides bipolar pacing.
At present, the guidewire has been used in five patients–of whom, two underwent transcatheter tricuspid valve-in-valve interventions. All patients received a Sapien 3 valve (Edwards Lifesciences), the mean threshold was 2.2±0.45mA with no loss of capture in any case, and no patients required pacing after implantation. There were no complications.
Overall, according to Hensey, the advantages of the Wattson guidewire is that it avoids the need for a transvenous pacemaker, which reduces the risk of complications, reduces procedural time, and reduces radiation exposure. Also, it provides “reliable bipolar pacing”.
“In our early experience, the Wattson wire delivered safe and effective pacing along with excellent rail support in both aortic and tricuspid positions. It does have the potential to make transcatheter heart valve implantation safer and more efficient,” Hensey concluded. However, he added that further clinical experience was required and that an “early feasibility study was underway”.
Hensey and colleagues recently published their early experiences with the guidewire in EuroIntervention.