European Journal of Cardiovascular Medicine

Chronic kidney disease (CKD) is a public health problem worldwide with a global prevalence of 11 to 13%¹. It is a pathophysiological process with multiple etiologies, resulting in inexorable attrition of nephron number and function leading to end stage renal disease.

More than 2 million people worldwide are estimated to be receiving treatment with dialysis or transplantation for chronic kidney failure, and this population has been growing at an approximate rate of 7% per year².

Cardiovascular diseases (CVD) are becoming the major cause of morbidity and mortality in most of the developing countries; including India in patients of chronic kidney disease³. Angina pectoris, myocardial infarction, arrhythmias, cardiac failure, stroke and peripheral vascular disease are common in end stage renal disease.

Four main structural abnormalities of the heart have been described in patients of CKD: Left ventricular hypertrophy (LVH), expansion of the non-vascular cardiac interstitium leading to inter-myocardiocytic fibrosis, changes in vascular architecture & myocardial calcification. All these abnormalities promote systolic as well as diastolic dysfunction which predisposes to symptomatic heart failure, which is a risk factor for premature death⁴.

Left ventricular (LV) dysfunction is a frequent occurrence in uremic patients and is an important adverse prognostic indicator. Echocardiographically proven LV hypertrophy, systolic dysfunction and dilatation are independent predictors of mortality in these individuals^5,6,7. The cardiovascular mortality in these individuals is 10 to 20-fold more frequent than that in general population⁸.

Although patients with CKD have a high prevalence of many traditional factors such as diabetes mellitus, hypertension & left ventricular hypertrophy; they are also exposed to non-traditional or uraemia related risk factors that increase in prevalence as the kidney function declines eg; anemia, hyperparathyroidism, hyper-homocysteinemia, proteinuria, hypoalbuminemia, activated renin angiotensin system, oxidative stress, elevated lipoproteins & lipoprotein remnants. The relative importance of non- traditional risk factors for cardiovascular disease (CVD) in CKD patients is not well understood⁴. Most of the patients with CKD succumb to CVD before reaching end stage CKD⁹.

Echocardiography is a non-invasive & easily reproducible tool for assessing the cardiac structural & functional abnormalities; having no adverse effects on the patient.

   In the present study, an attempt has been made to study the left ventricular systolic& diastolic functional status in CKD patients with the help of   echocardiography as very few Indian studies have been conducted on this subject. Any correlation of severity of CKD with left ventricular dysfunction will also be assessed. As CVD is the single most important cause of death among patients receiving long term dialysis (44% of total mortality¹⁰); echocardiography may help us to detect cardiac dysfunction in CKD patients at an earlier stage which may help in better monitoring & management of these patients.

AIM

To assess left ventricular functional status on echocardiography in chronic kidney disease

patients.

OBJECTIVES

1. To study the prevalence of Left ventricular Diastolic dysfunction on echocardiography in chronic kidney disease patients.
2. To study the prevalence of Left ventricular Systolic dysfunction on echocardiography in chronic kidney disease patients.
3. To assess any correlation between severity of chronic kidney disease and left ventricular dysfunction.

STUDY AREA: Deen Dayal Upadhyay Hospital, New Delhi.

STUDY POPULATION: Cases of chronic kidney disease admitted under medicine department & those attending the medical OPD of Deen Dayal Upadhyay Hospital, New Delhi.

TIME FRAME: The study is conducted for a period of 2 years from November 2017 to November 2019.

STUDY DESIGN: Observational Cross-sectional study.

        SAMPLE SIZE:

The study of Satish Sachdeva¹¹, observed that diastolic and systolic dysfunction was

present in 38.33% and 21.67% of CKD cases respectively. Taking this value as

reference, the minimum required sample size with 10% margin of error and 5% level of

significance is 91 patients. To reduce margin of error, total sample size taken is 100.

Formula used is: -

n ≥ {(p(1 -p)}/ (ME/

Where  is value of Z at two-sided alpha error of 5%, ME is margin of error and p

is proportion of diastolic and systolic dysfunction in CKD cases.

Calculations: -

1) Diastolic dysfunction

n >= {(.3833*(1-.3833)}/ (.1/1.96)² =90.81=91(approx.)

2) Systolic dysfunction

n>={(.2167*(1-.2167)}/(.1/1.96)²=65.21=66(approx.)

INCLUSION CRITERIA:

Patients of CKD admitted under the department of medicine & those attending the medical OPD of DDU Hospital.

SELECTION OF CKD PATIENTS: (Either of the following)

1. Azotemia for >3 months
2. Presence of broad casts in urinary sediment
3. Ultrasonography suggestive of chronic kidney disease (reduced renal cortical thickness <6mm, reduced renal length, increased cortical echogenicity, cysts)
4. GFR < 60 ml/min/1.73m² for > 3 months^12-14.

EXCLUSION CRITERIA:

1. Documented congenital heart disease
2. Valvular heart disease
3. Chronic alcoholics
4. HIV positive patients
5. Patients with AKI
6. Non sinus rhythm
7. Previous h/o MI
8. Cardiomyopathies
9. Pericardial effusion > 10 mm
10. Rheumatic heart disease

METHOD

CKD patients were selected on basis of selection criteria as mentioned above. All patients were subjected to complete relevant history and physical examination. The preliminary details and diagnosis were recorded in a case record form. After taking informed consent, these individuals were subjected to the following investigations: complete haemogram, renal function test (Blood urea, serum creatinine, GFR estimation) ; serum electrolytes, blood sugar level, urine routine microscopic examination for broad casts, HIV serology, Chest X-Ray, USG abdomen with KUB, ECG & Echocardiography.

GFR Estimation:

The CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equation is the most widely used estimating equation.

GFR estimation in this study was done using CKD-EPI equation

eGFR = 142 x min (standardized S.cr/K,1) ^α * max (standardized S.cr/K,1) ^-1.200 * 0.9938 ^{age in years} * 1.012 [if female]

where:

• cr = serum creatinine in mg/dL
• K = 0.7 (females) or 0.9 (males)
• α = -0.241 (females) or -0.302 (males)
• min (standardized S.cr/K,1) = the minimum of S.cr/K or 1
• max (standardized S.cr/K,1) = the maximum of S.cr/K or 1

Severity of CKD was assessed on basis of GFR estimation done using above mentioned formula & staging of CKD was done on basis of GFR as per kidney disease: Improving Global Outcomes (KDIGO) guidelines.

Staging Of Chronic Kidney Disease

In this study; stage 1-3 was considered as mild to moderate CKD group & stage 4-5 was considered as severe CKD group.

Echocardiography:

All the patients &controls were subjected to transthoracic echocardiographic examination using 2D, pulse Doppler and tissue Doppler mode. The study was carried out in Apical - four chamber & two chamber views. The echocardiography machine used for the study was Philips Envisor C1.5.

Method of evaluation of diastolic & systolic function:

1. Diastolic function:

Determined by measuring  E/A ratio by Pulse  Doppler  inflow velocity by keeping sample volume at the tip of mitral valve leaflets during end expiration(E is peak early diastole velocity & A is peak atrial filling velocity of left ventricle across mitral valve) and E/e’ ratio (e′ is the mitral annulus early diastolic velocity which is dependent on LV relaxation and as e′ corrects for the effect of LV relaxation on E, E/e′ ratio co-relates directly to LA pressure.)

An average value of three consecutive beats was taken.

2. Systolic function:

Determined by measuring left ventricular ejection fraction (LVEF) by using the biplane method of disks (Modified Simpsons Rule). LV volume was assessed in apical four chamber & two chamber window in systole & diastole.

LVEF was measured by using the following formula:

LVEF = LVVd - LVVs x 100

                     LVVd

Here, LVVd: Left ventricular volume in diastole

LVVs: Left ventricular volume in systole

Measurement of outcomes of interest:

1. It was considered as diastolic dysfunction when

• E/A ratio was less than 0.8 or more than 2 on 2D Echocardiography.
• OR E/e’ ratio >10 when the E/A ratio was pseudo-normal (0.8 to 2)

2. It was considered as systolic dysfunction when LVEF was less than 50 % on 2D echocardiography.

STATISTICAL ANALYSIS

Categorical variables were presented in number and percentage (%) and continuous variables were presented as mean ± SD and median. Normality of data was tested by Kolmogorov-Smirnov test. If the normality was rejected then non parametric test was used.

Statistical tests were applied as follows-

1. Quantitative variables were compared using independent t test/Mann-Whitney Test (when the data sets were not normally distributed) between the two groups.
2. Qualitative variables were correlated using Chi-Square test/Fisher’s Exact test.

A p value of <0.05 was considered statistically significant.

The data was entered in MS EXCEL spreadsheet and analysis was done using Statistical Package for Social Sciences (SPSS) version 21.0.

Out of 100 patients included in the study, maximum patients were between 41-50 years(30%) followed by 31-40 (28%),>60 (15%), 51-60 (14%) and <30 (13%).

50 patients each were included in mild/moderate CKD and severe CKD groups.

Out of 50 patients included in mild/moderate CKD group, maximum was between 41-50 years (34%) followed by 31-40 (32%), <30 (18%), >60 (10%) and 51-60 (6%). Out of 50 patients included in severe CKD group, maximum was between 41-50 years (26%) followed by 31-40 (24%), 51-60 (22%), >60 (20%) and <30 (8%).

More than half the patients were males (62%) & females were 38%. Out of 50 patients included in mild/moderate CKD group, 86% were males & 14% were females. Out of 50 patients included in severe CKD group, 62% were females & 38% were males.

Table 1 Stagewise distribution of CKD patients

Table 1 show stagewise distribution of CKD patients. Out of 100 CKD patients included in the study; maximum patients were in stage 3 (44%) followed by stage 4 (35%), stage 5 (15%) and stage 2 (6%).

Table 2

Table 2 depicts the mean, standard deviation, median & interquartile range of the various parameters of study viz. age, blood urea, e/a ratio, eGFR, LVEF and serum creatinine in CKD patients included in the study.

Table 3

Table 3 depicts the mean, standard deviation, median & interquartile range of the various parameters of study viz. age, blood urea, e/a ratio, eGFR, LVEF and serum creatinine in mild/moderate CKD and severe CKD groups.

Table 4 Prevalence of systolic dysfunction in CKD patients

Table 4 depict the prevalence of systolic dysfunction in CKD patients. Systolic dysfunction was present in 24% of CKD patients.

Table 5 Distribution of CKD patients having systolic dysfunction according to the severity of systolic dysfunction

Table 5 shows the distribution of CKD patients having systolic dysfunction according to the severity of systolic dysfunction. Majority of the patients fell in the category of moderate systolic dysfunction (41.67%) ;while  29.17 % patients fell in each of mild & severe systolic dysfunction categories.

Table 6 Prevalence of systolic dysfunction in mild/moderate CKD and severe CKD groups

Figure 1 Prevalence of systolic dysfunction in mild/moderate CKD and severe CKD groups

Table 6 & figure 1 depict the prevalence of systolic dysfunction in mild/moderate CKD and severe CKD groups. Systolic dysfunction was present in 6% mild/moderate CKD patients & in 42% severe CKD patients. The association of systolic dysfunction between these two groups was statistically significant.

Table 7 Prevalence of diastolic dysfunction in mild/moderate CKD & severe CKD groups

X² = 2.716Df = 1

Figure 2 Prevalence of diastolic dysfunction in mild/moderate CKD & severe CKD groups

Diastolic dysfunction was present in 58% CKD patients. Diastolic dysfunction was present in 46% mild/moderate CKD patients & in 70% severe CKD patients. The association of diastolic dysfunction between these two groups was statistically significant.

Table 8 E/A ratio in mild/moderate CKD & severe CKD groups

Table 8 depicts E/A ratio in mild/moderate CKD & severe CKD groups. E/A ratio <0.8 was seen in 34% of mild/moderate CKD group patients & in 24% of severe CKD group patients and the association between these two groups was statistically not significant. E/A ratio of 0.8-2 with an E/e’ ratio >10 was seen in 30% of severe CKD group patients & in 10% of mild/moderate CKD group patients and the association between these two groups was statistically significant.

E/A ratio > 2 was seen in 16% of severe CKD group patients & in 2% of mild/moderate CKD group patients and the association between these two groups was statistically significant.

Overall chi-square statics is 9.2184. the p- value is 0.00996, so result is significant (p<0.05).

Chronic kidney disease (CKD) is an important global public health problem. More than 2 million people worldwide are estimated to be receiving treatment with dialysis or transplantation for chronic kidney failure, and this population has been growing at an approximate rate of 7% per year. However, poor outcomes from CKD are not limited to kidney failure but also include a wide array of morbidity and mortality related to complications, particularly from decreased kidney function and cardiovascular diseases (CVD).

Many prospective and cross-sectional studies were done in the past to establish increased risk of cardiovascular mortality and morbidity in chronic kidney disease patients. Comparatively less studies were done on left ventricular haemodynamics & dysfunction. Older studies provided estimates based on serum creatinine cut-offs or the Cockroft–Gault (CG) equation to define CKD all of which are proved to be less accurate than the currently recommended CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equation-based estimations of glomerular filtration rate (GFR). In the present study we aimed to left ventricular function in CKD patients and assessed the correlation between severity of CKD and left ventricular dysfunction.

Age & gender Distribution

Out of 100 patients included in the study, maximum patients were between 41-50 years (30%) followed by 31-40 (28%), >60 (15%), 51-60 (14%) and <30 (13%); with mean age± SD 44.32 ± 12.64. More than half the patients included in the study were males (62%) & females were 38%. Out of 50 patients included in mild/moderate CKD group, 86% were males & 14% were females. Out of 50 patients included in severe CKD group, 62% were females & 38% were males.

In accordance with the previous studies, it can be concluded that that the prevalence of CKD is higher in males as compared to females in Indian population.

Stagewise distribution of CKD patients:

Table 1 shows that out of 100 CKD patients included in the study; maximum patients were in stage 3 (44%) followed by stage 4 (35%), stage 5 (15%) and stage 2 (6%). Thus, majority of the patients belonged to stage 3 & stage 4 CKD.

Blood Urea:

The mean blood urea among CKD patients included in this study was 89.14 ± 24.28mg/dl. The mean blood urea of mild/moderate CKD group patients was 74.18 mg/dl while that of severe CKD group patients was 104.1 mg/dl. The association between the two groups was statistically significant (p < 0.0001). In Agarwal et al²² study, the mean blood urea of mild/moderate CKD group patients was 80.1 ± 16.3mg/dl   while that of severe CKD group patients was 136.5 ± 30.2 mg/dl. In the study conducted by Laddha et al⁴, the mean blood urea level among ESRD patients was 151.7 ± 51.37 mg%.

Serum Creatinine:

The mean serum creatinine among CKD patients included in this study was 3.14 ± 1.46mg/dl. The mean serum creatinine of mild/moderate CKD group patients was 2.18 ± 0.38mg/dl while that of severe CKD group patients was 4.09 ± 1.51mg/dl. The association between the two groups was statistically significant (p < 0.0001). In the study conducted by Shivendra Singh et al²⁵, the mean serum creatinine level among ESRD patients was 8.13 ± 2.27mg/dl. In the study conducted by Shah Harsh et al²⁴, the mean serum creatinine of mild/moderate CKD group patients was 1.44 ± 0.43 mg/dl while that of severe CKD group patients was 5.89 ± 2.87 mg/dl. The mean serum creatinine in the study done by Gromadzinski et al²⁶ was 1.43 mg/dl in patients having eGFR 30 – 60 mL/min/1.73 m²& 2.95 mg/dl in patients having eGFR< 30 mL/min/1.73 m².

eGFR:

The mean eGFR among CKD patients included in this study was 26.96 ± 13.31 mL/min/1.73 m². The mean eGFR of mild/moderate CKD group patients was 37.48mL/min/1.73 m²; while that of severe CKD group patients was 16.44 mL/min/1.73 m². The association between the two groups was statistically significant (p < 0.0001). In the study conducted by Shah Harsh et al²⁴, the mean eGFRof mild/moderate CKD group patients was 70.02 ± 26.41 mL/min/1.73 m²while that of severe CKD group patients was 15.03 ±7.79mL/min/1.73 m².

LVEF & Systolic Dysfunction:

The mean LVEF among CKD patients included in this study was 49.92 ± 9.23 %.  The mean LVEF among mild/moderate CKD group patients was 55.5 ± 3.41% while that among severe CKD group patients was 44.34 ± 9.84%. The association between the two groups was statistically significant (p < 0.0001).

In the study conducted by Laddha et al⁴ , the mean LVEF among ESRD patients was54.91 ± 9.62. Ayus et al (1981)³⁰ found that pre-dialysis mean LVEF in end stage renal disease (ESRD) patients was 56 ± 2%. In Agarwal et al²² study, the mean LVEF among mild/moderate CKD group patients was 58.1 ± 6.9 while that among severe CKD group patients was 55.4 ± 9.8. In Shah Harsh et al²⁴ study, the mean LVEF among mild/moderate CKD group patients was 56.18 ±7.36 while that among severe CKD group patients was 51.17 ± 10. Thus, these studies suggest that LVEF is well maintained in patients with CKD which was also observed in the present study. In the study done by Debnath et al³¹, the mean LVEF among mild/moderate CKD group patients was 56 ± 7.57 while that among severe CKD group patients was 43.71 ± 9.24.

Systolic dysfunction was present in 24% of CKD patients in our study.

Foley et al⁹ had found that abnormalities of left ventricular structure and functions were very frequent on baseline echocardiography in ESRD patients &14.8%of them had systolic dysfunction. In the study conducted by Shivendra Singh et al²⁵, systolic dysfunction was present in 28% of patients. Echocardiographic findings in other studies have also observed presence of systolic dysfunction in 20% patients^,76. Agarwal S. et al²² had observed systolic dysfunction in 30% patients with severe CKD (S. Cr. >6 mg %). The study conducted by LaddhaM et al⁴ in 2014, reported systolic dysfunction in 24.3% of ESRD patients on hemodialysis. Zoccali C et al²³ had reported incidence of systolic dysfunction of 22% in ESRD population on hemodialysis. The above findings were consistent with our study.

Thus, in the present study, systolic function was well preserved in majority of patients with CKD which is in concordance with the previous studies done by Agarwal et al²², Greaves et al²¹, Colan et al³³, and Raj et al³⁴.

In our study systolic dysfunction was present in 6% of mild/moderate CKD patients & in 42% of severe CKD patients. The association of systolic dysfunction between these two groups was statistically significant (p = <0.0001).

In the study conducted by Agarwal et al²², systolic dysfunction was present in 3.3% of mild/moderate CKD patients & in 30% of severe CKD patients. The association between these two groups was statistically significant. In the Shah Harsh et al²⁴ study, systolic dysfunction was present in 3.7% of mild/moderate CKD patients & in 34.7% of severe CKD patients. The association of systolic dysfunction between these two groups was statistically significant (p = 0.013). In the study done by Debnath et al³¹,systolic dysfunction was present in 15% of  mild/moderate CKD patients & in 48% of severe CKD patients. The association of systolic dysfunction between these two groups was statistically significant (p =0.0261).

Diastolic Dysfunction & e/a Ratio:

The mean E/A ratio among CKD patients included in this study was 1.13± 0.53.  The mean E/A ratio among mild/moderate CKD group patients was 0.96±0.3 while that among severe CKD group patients was 1.29±0.64. The association between these two groups was statistically significant (p =0.033).

In the study conducted by Laddha et al⁴ , the mean E/A ratio among ESRD patients was0.95 ± 0.35. In Agarwal et al²² study, the mean E/A ratio among mild/moderate CKD group patients was 0.92 while that among severe CKD group patients was 0.96. In a study of ESRD patients by Virtanen et al³⁷, mean E/A ratio was 1.5 ± 0.5.

In our study diastolic dysfunction was present in 58% CKD patients.

In the study conducted by Shivendra Singh et al²⁵, diastolic dysfunction was detected in 51.42% of patients. Echocardiographic findings in other studies have also observed presence of diastolic dysfunction in about 50% patients. Agarwal et al²² had observed diastolic dysfunction in 53.2% patients with severe CKD (S. Cr. >6 mg %). The study conducted by Laddha M etal⁴ in 2014, reported diastolic dysfunction in 61.4% of ESRD patients on hemodialysis. The above findings were consistent with our study.

The above findings were consistent with our study.

In our study diastolic dysfunction was present in 46% of mild/moderate CKD patients & in 70% of severe CKD patients. The association of diastolic dysfunction between these two groups was statistically significant (p = 0.026).

In the study conducted by Agarwal et al²² diastolic dysfunction was present in 66.6% of mild/moderate CKD patients & in 53.2 % of severe CKD patients. The association between these two groups was statistically not significant. In the Shah Harsh et al²⁴ study, diastolic dysfunction was present in 51.85% of mild/moderate CKD patients & in 82.6% of severe CKD patients. The association between these two groups was statistically significant. The findings of our study were in concordance with the above-mentioned study.

In this study E/A ratio < 0.8 was seen in 34% of mild/moderate CKD group patients & in 24% of severe CKD group patients and the association between these two groups was statistically not significant (p= 0.841). E/A ratio of 0.8-2 with an E/e’ ratio >10 was seen in 30% of severe CKD group patients & in 10% of mild/moderate CKD group patients and the association between these two groups was statistically significant.

E/A ratio > 2 was seen in 16% of severe CKD group patients & in 2% of mild/moderate CKD group patients and the association between these two groups was statistically significant.

Thus, it shows that diastolic dysfunction is present in majority of CKD patients. There is a significant correlation between the prevalence of diastolic dysfunction between mild/moderate and severe CKD patients. The diastolic dysfunction present in mild/moderate CKD patients was almost entirely grade 1(impaired ventricular relaxation); while that seen in severe CKD patients comprised of mainly grade 2 (pseudo normal pattern- 30%), grade 1 in 24% patients along with some grade 3 dysfunction (restrictive pattern- 16%). Almost all patients of stage 5 CKD had diastolic dysfunction & nearly half of them had a restrictive pattern (grade 3). 

Left ventricular systolic and diastolic dysfunctions are significantly prevalent among chronic kidney disease patients.

The prevalence of systolic dysfunction increases with progressive decline in renal function. Also, systolic function is relatively well preserved in majority of mild/moderate CKD patients.

Also, the prevalence of diastolic dysfunction increases with the increase in severity of chronic kidney disease and significantly higher proportion of severe CKD patients have relatively higher grades of diastolic dysfunction in comparison to the corresponding mild/moderate CKD patient group. This emphasizes that the severity of LV diastolic dysfunction increases proportionately with the increase in the severity of CKD.

In comparison to systolic function, diastolic function was deranged in more number of patients suggesting that diastolic dysfunction is first to appear in patients with chronic kidney disease.

Echocardiography is a cost effective, noninvasive and easily reproducible diagnostic test which can detect early changes in the cardiac parameters. This is important for risk stratification and early preventive measures. Thus, echocardiographic screening of CKD patients has both therapeutic and prognostic implications. All asymptomatic CKD patients should undergo a routine echocardiographic evaluation.

Limitations of study:

• -Small study population
• -Single center study

1. Hill NR, Fatoba ST, Oke JL, Hirst JA, O’Callaghan CA, Lasserson DS, et al. Global Prevalence of Chronic Kidney Disease - A Systematic Review and Meta-Analysis. PLoS ONE. 2016;11(7):e0158765.
2. Lysaght, M. J. (2002). Maintenance dialysis population dynamics: current trends and long-term implications. J Am SocNephrol, 13, S37–40.
3. Lesaffre F, Wynckel A, Nazeyrollas P, Rieu P, Metz D. Echocardiography to predict adverse cardiac and vascular events in patients with severe chronic kidney disease (stage 4): A prospective study. Archives of Cardiovascular Diseases. 2013 Apr 1;106(4):220–7.
4. Laddha M, V Sachdeva, PM Diggikar, PK sapathy, AL Kakrani (2014) Echocardiographic assessment of cardiac dysfunction in patients of end stage renal disease on hemodialysis. JAPI 62: 28-32.
5. Foley RN, Parfrey PS, Harnett JD, Kent GM, Murray DC, Barre PK. The prognostic importance of left ventricular geometry in uremic cardiomyopathy. J Am SocNephrol1995;5:2024-2031
6. Parfrey PS, Foley RN, Harnett JD, Kent GM, Murray DC,Barre PE. Outcome and risk factors for left ventricular disorders in chronic uraemia. Nephrol Dial Transplant 1996;11:1277-1285.
7. London GM, Fabiani F. Left ventricular dysfunction in endstage renal disease: echocardiographic insights. In: Parfrey PS, Harnett JD, editors. Cardiac dysfunction in chronic uremia. Basel: Kluwer Academic Publishers, 1992:117-137.
8. Barberato SH, Pecoits – Filho R. Echocardiographic alternation in patients with chronic kidney failure undergoing haemodialysis. Arq Bras Cardiol2010 ; 94(1) : 131-7.
9. Foley RN, Parfrey PS, Harnett JD, Kent GM, Martin CJ, Murray DC, et al. Clinical and echocardiographic disease in patients starting end-stage renal disease therapy. Kidney Int. 1995 Jan;47(1):186–92.
10. US renal data system : USRDS 2005 Annual Data Report . The National Institute of  health , National Institute of Diabetes & Digestive & Kidney Diseases, Bethesda, MD, 2005.
11. Sachdeva S, Khurana T, Kaur S, Kamalpreet K, Aggarwal R, Kaur A, et al. ECG and Echo changes in CKD. AIMDR . 2017 Sep ;2(5).
12. Levey, A. S., Eckardt, K. U., Tsukamoto, Y., et al. (2005). Definition and classification of chronic kidney disease: a position statement from Kidney Disease: Improving Global Outcomes (KDIGO). Kidney Int, 67, 2089–100.
13. Levey, A. S., Stevens, L. A. and Coresh, J. (2009a). Conceptual model of CKD: applications and implications. Am J Kidney Dis, 53, S4–16.
14. Joanne M. Bargman, Karl L. Skorecki. Chronic Kidney Disease. In: Jameson, Fauci, Kasper, Hauser, Longo, Loscalzo, editors, Harrison’s Principles of Internal Medicine, 20^th New Delhi: McGraw Hill Education; 2018 p.2111-2113.
15. Delgado C, Baweja M, Crews DC, et al. A unifying approach for GFR estimation: Recommendations of the NKF-ASN Task Force on Reassessing the Inclusion of Race in Diagnosing Kidney Disease. Am J Kidney Dis. 2021;78(1):103-115.
16. Kramer HJ, Jaar BG, Choi MJ, et al,; National Kidney Foundation Kidney Disease Outcomes Quality Initiative. An Endorsement of the Removal of Race From GFR Estimation Equations: A Position Statement From the National Kidney Foundation Kidney Disease Outcomes Quality Initiative. Am J Kidney Dis. 2022;80(6):691-696
17. Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group (2013). KDIGO 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney IntSuppl, 3, 1–150.
18. Ritz E, Koch M. Morbidity and mortality due to hypertension in patients with renal failure. Am J Kidney Dis 1993; 21:113-118.
19. Rodby RA, Vonesh EF, Korbet SMK. Blood pressures in hemodialysis and peritoneal dialysis using ambulatory blood pressure monitoring. Am J Kidney Dis 1994;23:401-411.
20. Kunz K, Dimitrov Y, Muller S, Chantrel F, Hannedouche T. Uraemic cardiomyopathy. Nephrol Dial Transplant 1998; 13 Suppl4 :39-43.
21. Greaves SC, Gamble GD, Collins JF, Whalley GA, Sharpe DN. Determinants of Left Ventricular Hypertrophy and Systolic Dysfunction in Chronic Renal Failure. American Journal of Kidney Diseases. 1994 Nov 1;24(5):768–76.
22. Agarwal S, Dangri P, Kalra O, Rajpal S. Echocardiographic Assessment of Cardiac Dysfunction in Patients of Chronic Renal Failure. 2003;4(4):8.
23. Zoccali C, Benedetto FA, Tripepi G, Mallamaci F, Rapisarda F, Seminara G, et al. Left Ventricular Systolic Function Monitoring in Asymptomatic Dialysis Patients: A Prospective Cohort Study. JASN. 2006 May 1;17(5):1460–5.
24. Shah H, Rathod R, Ghodasara K. Assessment of cardiac dysfunction by 2D echocardiography in patients of chronic kidney disease. JPBMS. 2012 Jan 1;17.
25. Shivendra S. Echocardiographic Changes in Patients with ESRD on Maintenance Hemodialysis-A Single Centre Study. J Cardiovasc Dis Diagn. 2014 ;2(4).
26. Gromadziński L, Pruszczyk P. Echocardiographic Changes in Patients with Stage 3-5 Chronic Kidney Disease and Left Ventricular Diastolic Dysfunction. Cardiorenal Med. 2014 Dec;4(3–4):234–43.
27. Singh AK, Farag YM, Mittal BV, Subramanian KK, Reddy SRK, Acharya VN, et al. Epidemiology and risk factors of chronic kidney disease in India – results from the SEEK (Screening and Early Evaluation of Kidney Disease) study. BMC Nephrology. 2013 May 28;14(1):114.
28. Dharmaraj C, Antony TA, Prasannan G. A Study on Prevalence of Left Ventricular Dysfunction and Its Correlation with Estimated Glomerular Filtration Rate (eGFR) in CKD patients. In 2017.
29. Chronic Kidney Disease in the United States, 2019 [Internet]. Available from: https://www.cdc.gov/kidneydisease/publications-resources/2019-national-facts.html
30. Ayus JC, Frommer P, Olivero JJ, Young JB. Effect of long term dialysis on left ventricular ejection fraction in end stage renal disease. Kidney Int 1981; 19: 142A.
31. Debnath A, Chaudhury SR, Chaturvedi AN, Sarkar S, Mandal S et al. Echocardiographic Assessment of Left Ventricular Systolic Dysfunction in Chronic Kidney Disease Patients of a Rural Tertiary Medical Care Centre in West Bengal. IOSRJDMS. 2014;13(1):69–73.
32. McMurray JV, McDonagh TA, Davie AP, Cleland JG, Francis CM, et al. (1998)Should we screen for asymptomatic left ventricular dysfunction to prevent heart failure? Eur Heart J 19: 842-846.
33. Colan SD, Sanders SP, Ingelfinger JD, Harmon W. Left ventricular mechanics and contractile state in children and young adults with end- stage renal disease: Effect of dialysis and renal transplantation. J Am CollCardiol 1987; 10: 1085-94.
34. Raj DSG, D’Mello S, Soniah S et al. Left ventricular morphology in chronic renal failure by echocardiography. Renal Failure 1997; 19 (6): 799-806.
35. Schroeder AP, Kristensen BO, Neilsen CB, Pedersen EB. Heart function in patients with chronic glomerulonephritis and mildly to moderately impaired renal function. Blood Pressure 1997; 6: 286-93.
36. Appleton CP, Hatle LK. The natural history of left ventricular filling abnormalities: assessment by two dimensional and Doppler echocardiography. Echocardiography 1992; 9: 437- 57.
37. Virtanen VK, Saha HH, Groundstroem KW, Seppälä ES, Pasternack AI. Calcium infusion and left ventricular diastolic function in patients with chronic renal failure. Nephrol Dial Transplant. 1998 Feb;13(2):384–8