Tissue Puncture Effectiveness
The RF wire required on average 1.10 ± 0.47 attempts to cross the
septum. The 0.014” electrified guidewire required an overall mean of
2.17 ± 2.36 attempts (2.0 times as many as the RF wire;
p<0.01), and the 0.032” electrified guidewire required an
overall mean of 3.90 ± 2.93 attempts (3.5 times as many as the RF wire;
p<0.01, Figure 3A). Across power output levels, the 0.014”
electrified guidewire required a range of 1.2-2.6 times as many
applications as the RF wire, and the 0.032” electrified guidewire
required 3.4-4.1 times as many attempts as the RF wire to perforate the
septum (Figure 3B). The number of RF applications was significantly more
consistent for the RF wire than both 0.014” and 0.032” electrified
guidewires (p<0.001, Figure 3B). Increase in the power applied
to electrified guidewires, from 20W to 50W, did not significantly
improve the consistency in TSP success. Across all power settings, the
0.014” and 0.032” electrified guidewires failed to puncture the septum
in 6% and 19% of tissues, respectively. The RF wire did not fail to
perforate any of the tissue specimens.
While the dilator-wire tip distance had no measurable effect on the rate
of successful puncture using the RF wire, an increase in distance from
1mm to 5mm reduced TSP effectiveness for both 0.014” and 0.032”
electrified guidewires (Figure 3C). At 1mm dilator-wire tip distance,
all wires perforated the septum on the first attempt. However,
increasing the distance to 3mm and 5mm required more RF attempts and
introduced variability in the TSP effectiveness, especially for
electrified guidewire. At the maximum dilator-wire tip distance tested
(5mm), the 0.014” electrified guidewire required 5.8 ± 3.4 attempts for
TSP and failed to puncture in 40% of the septa after 8 attempts, while
the 0.032” electrified guidewire failed to puncture in all septa after
8 attempts (Figure 3C).