Discussion
In the present study, the cumulative rate of progressive TR ranged from
1.3% in the first year to 18.4% in the sixth year. Higher pre-implant
TRPG and larger post-implant LA dimension were positively associated
with progressive post-implant TR, which was associated with a trend
toward HF hospitalization.
TR occurs mainly due to annular dilation and right ventricular
enlargement, often secondary to LV dysfunction from myocardial or
valvular causes, right ventricular volume and pressure overload, and
cardiac chamber dilations 11. Lead-related TR is an
underdetermined problem and may be caused by lead-related tricuspid
leaflet injury or perforation or lead entanglement, impingement, or
adherence to the tricuspid valve 6. However,
lead-related tricuspid valve injury could not be fully detected and was
only observed in 12% of patients with PPM-related severe TR by
transthoracic echocardiography 6. Kim et al. reported
that abnormal TR developed in 21.2%, worsened TR by ≥1 grade in 24.2%,
and progressed to severe TR in 3.9% of patients with initially normal
TR 4. However, Al-Bawardy et al. reported a small but
significant increase in the prevalence of moderate and severe TR, both
acutely and chronically after a cardiac device implantation5. Arabi et al. reported that TR was worsened by 1
grade in 70.8% and 2 grades in 17.1% of patients, and 19.5% of
patients without baseline TR developed new-onset TR after the lead
implantation in the follow-up period 12. In this
study, the cumulative rate of progressive post-implant TR (increased TR
grade of ≥2 degrees and/or TRPG of >30 mmHg) was from 1.3%
in the first year to 18.4% in the sixth year. Moreover, higher
pre-implant TRPG and larger post-implant LA dimension were independent
predictors of progressive post-implant TR. Pacing-induced electrical and
mechanical dyssynchrony of LV can also result in TR and MR13. However, in this study, pacing percentage and
pacing QRS length was not associated with the development of progressive
post-implant TR. In this study, larger post-implant LA size was an
independent predictor of progressive post-implant TR. Our previous study
showed that right and left atrial sizes were larger in patients with
atrioventricular dyssynchrony after pacing 14. Atrial
enlargement is a well known predictor of atrial fibrillation. Utsunomiya
et al reported that functional TR with a structurally normal tricuspid
valve may occur secondary to chronic atrial fibrillation and is
associated with advanced age and right atrial enlargement15.
In one small retrospective cohort study, significant lead-induced TR was
associated with a significantly increased incidence of all-cause
mortality and HF events in patients after PPM implantation16. Other studies also reported post-implant TR to be
an independent risk factor for late death 5, 13.
However, a significant proportion of patients in previous studies
included patients with HF and receiving ICD and cardiac
resynchronization therapy (CRT). Patients with ICDs and/or CRT devices
usually have poor LVEF and advanced HF and consequently, higher incident
HF hospitalization and mortality. In our study, we only enrolled
patients receiving PPM implantation and excluded patients receiving ICD
or CRT and those with prior history of HF, valvular heart disease and
preexisting abnormal (mild-moderate, moderate or severe) TR and abnormal
(>30 mmHg) TRPG. In this large cohort study, progressive
post-implant TR was significantly associated with HF hospitalization in
univariate analysis and was associated with a non-significant trend
toward HF hospitalization (p = 0.070) in multivariate analysis (Table
5), and progressive post-implant TR was not associated with
cardiovascular and all-cause mortality. Therefore, patients with
preserved LV function and without valve disease underwent transvenous
ventricular-based pacemaker implantation should have baseline
echocardiography evaluation before implant and those with higher
pre-implant TRPG should have more vigorously echocardiographic follow-up
for the development of progressive post-implant TR.