DISCUSSION
In the present study, we investigated the impact of different dialysis
modalities on echocardiographic RV function in ESRD patients with
preserved left ventricular function. We demonstrated that patients on HD
with AVF have poorer RV function compared with the patients undergoing
PD and HD treatment is an independent risk factor for developing RV
dysfunction.
Heart failure is associated with significant morbidity and mortality in
ESRD patients on dialysis, however it remains poorly investigated. RV
dysfunction has been reported as a significant indicator of mortality in
heart failure patients, regardless of left ventricular systolic
dysfunction and valvular disease. 12 A survival
analysis including echocardiographic parameters reported that RV
dysfunction is significantly associated with impaired survival in ESRD
patients. 13 There is data suggesting that RV
dysfunction is more common in patients on HD. 14Several pathophysiological mechanisms may be responsible for the
deterioration of RV function: sympathetic activation, anemia, secondary
hyperparathyroidism, inflammation and left-to-right shunt caused by AVF.15AVF leads to chronic volume overload, causing left
to right shunt. Data from several studies suggest that mortality and
heart failure prevalence may be increased in AVF patients.16,17 In a study by Reddy et al., it was reported that
AVF creation for the initiation of HD in patients with ESRD, is
associated with modest impairment in LV function and remodeling in the
RV. 18 Another study using strain echocardiography,
demonstrated that patients with ESRD and preserved LV EF undergoing HD
have higher prevalence of LV diastolic dysfunction and reduced RV
longitudinal function and deformation parameters, compared with healthy
controls. 19 Sun et al. suggested that patients on HD
endure the deterioration of RV function and demonstrated RV
morphological and dysfunction, compared with control group.20 Karavelioglu et al. also stated that RV functions
were deteriorated in ESRD patients on HD compared to healthy subjects.21
There is, however, a lack of data on the impact of different dialysis
modalities on RV function. In the present study, we compared the
long-term impacts of PD and HD with AVF on RV function in ESRD patients
with preserved LV systolic function and demonstrated the deterioration
of RV function in HD patients, compared with the patients on PD. TAPSE
and tricuspid lateral annulus Sa values, which reflect the systolic
function of RV, were found to decrease; additionally, RV MPI, an
indicator of global RV function, was found to increase in patients on HD
compared with PD patients. Logistic regression analysis demonstrated HD
treatment as an independent predictor of RV dysfunction and also Ea
velocity of tricuspid lateral annulus, as associated with RV
dysfunction. Our results were consistent with a previous, similar study
by Paneni et al., that investigated RV function in different dialysis
modalities. They demonstrated a higher prevalence of RV dysfunction
among HD patients when compared to patients on PD and also noted that RV
dysfunction was more prevalent in brachial AVF patients, compared to the
patients with radial AVF. 22 Different from Paneni’s
study that evaluated RV MPI and tricuspid lateral annulus Sa velocities,
we also investigated TAPSE and RV FAC, and defined a classification
score, indicating RV function of the patients, by using these four
echocardiographic parameters. The results of the present study emphasize
the deterioration of RV function in patients undergoing HD, regardless
of LV function and PASP, compared with the subjects on PD; this suggests
the deterioration of RV independent of LV dysfunction and pulmonary
hypertension.
Considering the vital role of RV dysfunction in the development of heart
failure in ESRD patients, the choice of dialysis treatment modality is
of great importance for patients at high risk for heart failure.
Additionally, close follow-up of HD patients for RV function is
necessary for detection, prevention and early treatment of heart failure
in this patient group.
The lack of gold standards, such as magnetic resonance imaging or strain
echocardiography for the assessment of RV and LV function is the main
limitation of the present study. However, despite the difficulties in
the evaluation of RV due to its complex anatomy and retrosternal
position, transthoracic echocardiography is an accurate, easy, rapid,
reproducible and noninvasive method to assess RV function. Further
larger scale studies are needed to confirm these results and also
evaluate the clinical importance and prognostic value of the results.
In conclusion, this study has demonstrated that RV function assessed by
echocardiography was poorer in patients undergoing HD with AVF compared
to the patients on PD, regardless of LV function and pulmonary
hypertension. Accordingly, HD patients should be evaluated frequently
for the development of RV dysfunction. The echocardiographic parameters
reflecting RV function, should be examined and reported in patients on
HD.