Left ventricular hypertrophy in chronic kidney disease

Introduction: Cardiovascular disease is a major cause of death in patients with chronic kidney disease (CKD). Mortality due to cardiovascular events is ten to twenty times greater than in general population. Left ventricular hypertrophy (LVH) is an independent predictor of mortality in chronic kidney disease patients. There are only a few studies which have looked at cardiovascular disease in Indian chronic kidney disease patients. Materials and Methods: This was a cross-sectional study of 100 consecutive chronic kidney disease patients in the nephrology department of our hospital. They were divided into mild, moderate and severe chronic kidney disease. The various parameters were then compared between these three groups using the Tukey’s test. A P value <0.05 was considered signifi cant. Results: Out of the 100 patients, 69 had LVH. In the severe disease category, 39 patients (88.63%) had LVH. In the moderate group, 18 patients (51.42%) had LVH. In the mild group, 12 patients (57.14%) had LVH. Only anemia was found to correlate with the presence of LVH. Conclusion: A signifi cant number of CKD patients had LVH and the highest numbers of LVH were found in the severe CKD group.


INTRODUCTION
Cardiovascular disease is a major cause of death in patients with chronic kidney disease (CKD).According to literature the mortality due to cardiovascular events is ten to twenty times greater than in general population. [1]Left ventricular hypertrophy (LVH) is an independent predictor of mortality in CKD patients. [2]Though there are many studies on cardiovascular disease in CKD patients, there are few studies which have looked at cardiovascular disease in Indian CKD patients.Datta in a study in Chennai estimated the prevalence of LVH to be around 78% in CKD patients. [3]Hence, we undertook this study to look at LVH, an important marker of cardiovascular disease in CKD patients in south western part of India.All subjects underwent a detailed history and physical examination.The following investigations were done for all the patients.Complete hemogram, serum creatinine, urine routine, ultrasound of the abdomen, serum sodium, potassium, calcium, phosphorus, electrocardiogram and echocardiography.CKD was classifi ed as mild [glomerular fi ltration rate (GFR) >60 ml/min per 1.73 m 2 ], moderate (GFR: 30-60 ml/min per 1.73 m 2 ) and severe (GFR < 30 ml/min per 1.73 m 2 ). [4]The GFR was calculated using the method that was given by Modifi cation of Diet in the Renal Disease study group. [5]Echocardiography: Measurements were performed using two-dimensional guided M-mode as recommended by American society of echocardiography. [6]Left ventricular mass was calculated using the Devereux-modifi ed method. [7]Left ventricular mass index (LVMI) was calculated by dividing the left ventricular mass by body surface area.LVH was defi ned when LVMI exceeded 134 g/m 2 and 110 g/m 2 for men and women, respectively. [8]atistics: The CKD patients were divided into mild, moderate and severe categories.The various factors were then compared between these three groups using Tukey's test, which is the test used for intergroup comparisons.A P value of <0.05 was taken as signifi cant.

RESULTS
There were 33 female and 67 male patients.All the patients in the study belonged to the age group of 41-80 years.Most of the patients i.e., 41 patients belonged to the age group of 61-70 years.As shown in Table 1, maximum number of patients belonged to the severe CKD group.Out of the total 100 patients, 69 patients had LVH.In the severe CKD group, 39 patients (88.63%) had LVH.In the moderate CKD group, 18 patients (51.42%) had LVH.In the mild CKD group, 12 patients (57.14%) had LVH.Table 2 shows the comparison of various parameters between the mild, moderate and severe CKD patients.Statistically significant differences were observed only for hemoglobin and serum creatinine values.Hemoglobin was signifi cantly lower in the severe CKD group when compared to the moderate and mild categories.Serum creatinine was signifi cantly higher in the severe CKD group when compared to the moderate and mild CKD groups.There was no statistically signifi cant difference seen in the age, blood pressure and serum calcium between the three categories of CKD patients.

DISCUSSION
There are many risk factors for LVH in CKD patients.Anemia, hypertension, extra-cellular fl uid expansion, arterio-venous fi stulas and abnormalities of calcium phosphate homeostasis are some of the common mechanisms described. [9]Zocalli et al. had shown a 50% mortality risk and more than 85% cardiovascular event risk at 3 years in the patients who had signifi cant increase in left ventricular mass while undergoing dialysis. [10]In our study, we found LVH to increase with the severity of CKD.In the severe CKD group, 88.63% had LVH.Similar observations were noted by Paoletti et al., who found a steady increase in the LVH as the renal dysfunction progressed during the predialysis stage of CKD.In their study they found that 70% to 80% of the severe CKD patients had LVH before the initiation of dialysis. [11]In our study, statistically signifi cant difference was seen only with the hemoglobin values which were found to decrease as the severity of CKD progressed.However, the blood pressure and the serum calcium values of the various degrees of CKD did not vary signifi cantly.But a study done in Chennai found that the severity of anemia and hyperparathyroidism correlated well with the severity of LVH. [12]Londen et al. who followed up a cohort of patients on hemodialysis for 5 years found that a 10% decrease in left ventricular mass resulted in 28% decrease in mortality risk from cardiovascular causes. [13]Hence, early identifi cation and treatment aimed at regressing the LVH can result in better outcomes in CKD patients.This is important as LVH by itself is known to predispose to ischemic heart disease, arrhythmias and congestive cardiac failure. [14]

Limitation
In order to see the exact relation between factors such as blood pressure, anemia, age, calcium and LVH in CKD patients, a study with a larger sample size would be needed.

Table 1 : Severity of chronic kidney disease and left ventricular hypertrophy
*CKD: Chronic kidney disease