Abstract
Background: The right phrenic nerve is vulnerable to injury
(rPNI) during cryoballoon ablation (CBA) isolation of the right
pulmonary veins. The complication can be transient or persistent. The
reported incidence of rPNI fluctuates from 4.73% to 24.7% depending on
changes over time, CBA generation, and selected protective methods.
Methods: Through September 2019, a database search was
performed on MEDLINE, EMBASE, and Cochrane Database. In the selected
articles, the references were also extensively searched. The study
provides a comprehensive meta-analysis of the overall prevalence of
rPNI, assesses the transient to persistent PNI ratio, the outcome of
using compound motor action potentials (CMAP), and estimated average
time to nerve recovery.
Results: From 2008 to 2019, 10,341 records from 48 trials were
included. Out of 783 eighty- PNI (7.7%), 589 (5.7%) were transient,
and 194 (1.9%) were persistent. CMAP caused a significant reduction in
the risk of persistent PNI from 2.3% to 1.1% (p = 0.05; odds ratio
[OR] 2.13) in all CBA groups. The mean time to rPNI recovery
extended beyond the hospital discharge was significantly shorter in CMAP
group at three months on average versus non CMAP at six months (p =
0.012). CMAP (in contrast to non-CMAP procedures) detects PNI earlier
from 4 to 16 sec (p < 0.05; I2 = 74.53%) and
3 to 9ยบ (p < 0.05; I2 = 97.24%) earlier.
Conclusions: rPNI extending beyond hospitalization is a
relatively rare complication. CMAP use causes a significant decrease in
the risk of prolonged injury and shortens the time to recovery.