Page 12 - Read Online

Tummala et al. Vessel Plus 2022;6:17 https://dx.doi.org/10.20517/2574-1209.2021.114 Page 5 of 15

[26]
linked with POAF .

TAVR
Similar to the explanation of POAF after SAVR procedures, a systemic inflammatory response is considered
why atrial fibrillation develops following TAVR procedures. Inflammation and atrial oxidative stress lead to
slower atrial conduction and shorter refractoriness. These changes induce re-entry and ectopic activity,
which lead to atrial remodeling and tissue fibrosis, which ultimately result in atrial fibrillation
development .
[28]
In predicting POAF following TAVR, key risk factors include hemodynamic instability, atrial size, and
procedural access site. Hemodynamic instability during the procedure has been shown to be one of the
strongest predictors, with a ninefold increase in the risk of POAF (OR = 9.3; 95%CI: 1.5-59) . A left atrial
[25]
size ≥ 27 mm/m on echocardiography has shown the highest sensitivity (67%) and specificity (61%) for
2
predicting POAF in patients following TAVR . Transapical access TAVR has been associated with a
[29]
[25]
fivefold increase in POAF risk compared to a transfemoral approach (OR = 4.96; 95%CI: 1.9-13.2) . While
the patients undergoing transapical TAVR generally have more pre-existing comorbidities than those
undergoing transfemoral TAVR, the increased incidence of POAF with the transapical approach may be
attributed to epicardial and pericardial injury caused by the procedure approach [28,30] . In comparison to
transfemoral procedures, transapical procedures are more associated with systemic inflammatory responses,
similar to those seen after SAVR. In addition, the onset of a majority of POAF episodes occurs during the
[30]
first 48 to 96 postprocedural hours, which matches the timing of peak inflammatory responses . Not only
does transapical TAVR increase POAF risk, but transaortic TAVR also increases the risk of POAF in
comparison with a transfemoral approach. While subclavian TAVR is associated with a slightly higher risk
[31]
of POAF than transfemoral TAVR, it is not statistically significant . Other risk factors of POAF following
TAVR include age, low left ventricular ejection fraction, previous cerebrovascular events, worse functional
status (New York Heart Association classes III or IV), chronic lung disease, balloon aortic valvuloplasty,
and periprocedural complications such as cardiac tamponade .
[30]
Similarities in POAF risk factors following SAVR and TAVR include age, low left ventricular ejection
fraction, increased left atrial size, and inflammatory responses. However, TAVR POAF is associated with
many more studies examining predictive risk factors. In addition, multiple diagnostic approaches using
anatomical or electrocardiograph parameters to predict POAF following TAVR are currently being
[28]
investigated . Given the scarcity of articles on the predictive risk factors of POAF following SAVR,
compared to the list of studies on the risk factors of TAVR POAF, there should also be more exploration
into the prediction of POAF after SAVR. It is essential to effectively predict the risk of POAF after SAVR or
TAVR so that patients can be better protected and managed.

NEW-ONSET POAF RATES
SAVR and TAVR
New-onset postoperative atrial fibrillation is a known complication of various cardiac procedures, with
overall incidence usually ranging from 20%-50%. Specifically focusing on SAVR and TAVR, new-onset
atrial fibrillation is a significant postoperative complication and has been shown to impact both short-term
and long-term outcomes dramatically. The incidence rates of SAVR and TAVR differ based upon both
follow-up time and type of procedure. Despite this, several studies have indicated significantly increased
rates of POAF following SAVR when compared to TAVR. The rates for POAF following SAVR procedures
have been noted to range from 11.1%-84% [Table 3]; the rates for POAF following TAVR procedures range
from 3.0% to 55.6% [Table 4]. Further, Tanawuttiwat et al. reported the incidence of new-onset atrial
[32]