**2. Venous thromboembolism and chronic kidney disease**

Pulmonary embolism and Deep Vein Thrombosis are a wide spectrum of a single disease defined as Venous Thromboembolism, and it occurs for the first time in approximately 100 persons per 100,000 each year in the United States and rises exponentially from less than 5 cases per 100,000 persons at 15 years and less to approximately 500 cases per 100,000 persons at age 80 years (White, 2003; Ageno, 2006; Heit, 2008).

An understanding of the risk factors for venous thrombosis is necessary in order to increase the prevention of this disease in high risk individuals and groups of patients.

The major risk factors for thrombosis include endogenous pattern characteristics like obesity and genetic factors, and triggering factors such as surgery, immobility or pregnancy. Venous thrombosis tends to occur due to additive effects of endogenous, genetic and environmental risk factors present simultaneously (Cushman, 2007).

Venous Thromboembolism in Neonates, Children and

Patients with Chronic Renal Disease – Special Considerations 43

was 149.9/100,000 dialysis patients, compared with 24.6/100,000 persons in the general population. In this study the younger dialysis patients had the greatest relative risk for pulmonary embolism (Tveit, 2002). Similar results by Allen et al, that showed an incidence

Several studies consider Nephrotic Syndrome as a risk factor for venous thromboembolism. In one of the largest studies, Kayali el al, studied 925,000 patients discharged from hospitals in the United States with the diagnosis of nephrotic syndrome, 0.5% had pulmonary embolism, 6.5% had deep vein thrombosis and less than 0.5% had renal vein thrombosis. The relative risk of pulmonary embolism (in patients with the nephrotic syndrome) was 1.39 and for deep vein thrombosis was 1.72. Among patients aged 18-39 years the relative risk of

Another prospective study of 298 patients with nephrotic syndrome, with a mean follow up of 10±9 years, the annual incidence of venous thromboembolism was 1.02%, over the first 6 months of follow up; the rate of venous thromboembolism was 9.85. In this group of patients, proteinuria and serum albumin levels tended to be related to venous tromboembolism, however, only the predictive value of the ratio of proteinuria to serum albumin was significant but not the estimated glomerular filtration rate.(Bakhtawar, 2008) For instance, estimated glomerular filtration rate using cystatin C, albuminuria and ratio proteinuria to serum albumin have predictive value for venous thromboembolism in

In renal transplantation, few studies had evaluated the risk of venous thromboembolism, the largest one used the United States Renal Data System database to study 28,924 patients receiving a kidney transplant, the rate of VTE occurring 1.5 to 3 years after transplantation was 2.9 episodes/1,000 person-years. Estimated glomerular filtration rate less than 30 mL/min/1.73 m2 versus higher at the end of the first year after renal transplantation was associated with significantly increased risk for later venous thromboembolism (adjusted hazard ratio, 2.05; 95% confidence interval, 1.08 to 3.89). Patients with severe chronic kidney disease, after renal transplantation should be regarded as high risk for late venous tromboembolism, which is a potentially preventable cause of death in this population

A prospective study of a cohort of 578 patients with renal transplantation, reports 9.1 % incidence of deep vein thrombosis of the lower limbs, 39.5% were asymptomatic and the diagnosis was made during routine ultrasound examination. Those patients, who experience venous thromboembolism, were at high risk of recurrence after

Co-morbilities like diabetes mellitus could increase the risk of venous thromboembolism, in a prospective study the frequency of deep vein thrombosis during the first 3 weeks after kidney transplantation has been evaluated using the combination of thermography and strain-gauge plethysmography for objective diagnosis. 83 consecutive

of 8.3% of venous thromboembolism in dyalisis patiens (Allen, 1987).

**2.1.3 Nephrotic syndrome and venous thromboembolism** 

deep vein thrombosis increases to 6.81 (Kayali, 2008).

**2.1.4 Renal transplantation and venous thromboembolism** 

patients with chronic renal disease.

thromboprophylaxis withdrawal (Poli, 2006).

(Abbott, 2004).

Chronic kidney disease is common in the general population, affecting 13% of adults in the United States between 1999 and 2004 (Coresh 2007).

There are several questions about the relation between venous thromboembolism and chronic kidney disease. Is the chronic kidney disease a risk factor for venous thromboembolism? What are the mechanisms involved in these diseases? And finally how to treat these patients?
