Echocardiographic Assessment of Systolic Time Intervals in Hemodialysis Patients with Normal Ejection Fraction.

INTRODUCTION : Chronic Kidney Disease (CKD) and Cardiovascular Disease (CVD) have been inextricably linked since the earliest days of chronic dialysis. Several statistics accrued since that time attest to the impact of cardiovascular disease in renal patients. Approximately one half of all deaths in end stage renal disease patients are attributable to cardiovascular disease, a proportion that is remarkably similar throughout the world. Several factors are thought to contribute to this high burden of cardiac disease in chronic kidney disease patients. First, the prevalence of many traditional risk factors for Cardiovascular disease such as diabetes, hypertension is higher among CKD patients than in general population. Second, several metabolic and hemodynamic disturbances that occur and progress in relation to declining renal function may modify cardiovascular risk. There is growing evidence that, uremia-related risk factors (Anemia, hypercholesterolemia, hyperhomocystinemia, divalent ion abnormalities, oxidative stress) contribute to the excess burden of cardiovascular disease in chronic kidney disease patients. The frequency of fatal and non-fatal cardiovascular events is increased even in the earliest stages of chronic kidney disease. It appears that uremia acts to amplify the incidence of fatal ischemic heart disease by a constant factor irrespective of the baseline incidence in the general population. OBJECTIVES : The objectives of this controlled study are: i) Evaluate latent systolic dysfunction and ii) Its relation with diastolic dysfunction in hemodialysis patients with normal ejection fraction, using Doppler derived systolic time intervals. MATERIALS AND METHODS : The study population included 25 hemodialysis patients (21 male, 4 female, mean age 36+ years) and 25 healthy controls (15male, 10 female, mean age 37+ 10 years). Patients who were on dialysis longer than three months were included in this study. Eighteen patients were dialysed thrice weekly and the remaining seven patients received dialysis twice weekly. Patients with systolic and diastolic blood pressures above 140 and 90mm Hg were grouped as hypertensive. According to this classification, 44% of patients were hypertensive. The control group comprised of healthy normotensive persons with no cardiovascular complaints, normal electrocardiogram (ECG) and normal blood chemistries. CONCLUSION : 1. The most common features of uremic cardiomyopathy namely left ventricular hypertrophy, diastolic dysfunction and systolic dysfunction were present in 40%, 24%, and 40% of our hemodialysis patients respectively. 2. The diastolic dysfunction and latent systolic dysfunction (STI>0.4) were randomly distributed. 3. Impaired STI index and prolonged Isovolumetric relaxation time are independent of the presence of hypertension or left ventricular hypertrophy. 4. 90% of patients with systolic dysfunction had normal Isovolumetric relaxation time. 5. 84.4% of patients with diastolic dysfunction (IVRT >100 m sec) had normal STI index. 6. Combined systolic and diastolic dysfunction were present in 12% of our hemodialysis patients. 7. Isovolumetric relaxation time is more sensitive than E/A ratio in the diagnosis of diastolic dysfunction in our hemodialysis patients.