Prevalence and clinical characteristics of venous thromboembolism at the Aga Khan University hospital, Nairobi
Date of Award
Master of Medicine (MMed)
Internal Medicine (East Africa)
Aim: To determine the prevalence of venous thromboembolism in patients presenting to the Aga Khan University Hospital, Radiology Department for lower limb compression ultrasonography with doppler and CT pulmonary angiography. In those found to have venous thromboembolism, the distribution of risk factors as described by Wells, the pattern of clinical presentation, the pattern of initial therapy, the length of hospital stay, major bleeding episodes and in hospital mortality were described.
Design: Prospective survey
Background: Venous Thromboembolism is a major cause of morbidity and mortality worldwide and its occurrence locally, as well as its clinical characteristics needs to be described in order to inform policy on prevention and treatment.
Patients and Settings: Patients presenting to the Aga Khan University Hospital, Nairobi, Radiology Department for CT Pulmonary Angiography and Lower Limb compression ultrasonography with Doppler formed the study population.
Methodology: All eligible patients undergoing CT pulmonary angiography and compression ultrasonography during the study period were entered into a database. In those found to have venous thromboembolism, a questionnaire was administered to assess risk factors, presentation, treatment and outcome of venous thromboembolism, with subsequent analysis. The prevalence of venous thromboembolism amongst those undergoing CT pulmonary angiography and compression ultrasonography was calculated as a proportion with 95% confidence interval.
Results: Four hundred and ninety one patients had CT pulmonary angiography and lower limb compression ultrasonography with Doppler of which 55 were found to have venous thromboembolism. The prevalence of venous thromboembolism was 11.2% (95% C.I 8.41-13.99). Twenty eight patients (50.9%) had risk factors as described by Wells, with the most common being malignancy, the bedridden state and a previous history of venous thromboembolism, each occurring in 7 (12.7%) of the patients with risk factors. The most common clinical presentations were dyspnoea (73.3%), chest pain (40%) and tachycardia (53.3%) for pulmonary embolism, and lower limb swelling (88%) and lower limb pain (88%) for deep vein thrombosis .Eighteen (33%) of the 55 patients with venous thromboembolism were initiated on low molecular weight heparin which was the most common initial therapy used. In contrast the most common discharge anticoagulant was rivaroxaban used in 19 (44%) of hospitalized patients at discharge. Mean length of hospital stay was 4.2 days (SD±2.1 days, range 1-11 days). Admission to critical care units occurred in 22 (48.9%) of admitted patients. Two patients (4.4%) had major bleeding episodes while 2 patients (4.4%) died in the course of the admission.
Conclusion: Based on these results we concluded that the prevalence of venous thromboembolism in patients undergoing lower limb compression ultrasonography with doppler, and CT pulmonary angiography at the Aga Khan University Hospital was 11.2% (95% CI 8.41-13.94). Half of the patients with venous thromboembolism did not have risk factors as described by Wells. Dyspnoea, chest pain, tachycardia and lower limb pain and swelling were common presenting symptoms and signs. The most common discharge medication was a novel oral anticoagulant. There was a high rate of admission to critical care, though overall hospital stay was short. Major bleeding and in hospital mortality was rare.
Riunga, F. M. (2014). Prevalence and clinical characteristics of venous thromboembolism at the Aga Khan University hospital, Nairobi (Unpublished master's dissertation). Aga Khan University, East Africa.
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