New hope for an old cure: a pilot animal study on selective venesection in attenuating the systemic effects of ischaemic-reperfusion injury.

INTRODUCTION: Reperfusion of acutely ischaemic tissue may, paradoxically, lead to systemic complications. This phenomenon is believed to be initiated by humoral factors that have accumulated in the ischaemic tissue. The ancient art of venesection may reduce the load of these mediators at the point of reperfusion. The aim of this study is to test if selective venesection, by removing the initial venous return from the ischaemic tissue, can attenuate the systemic effects of the ischaemic-reperfusion injury using a porcine model of acute limb ischaemia. MATERIALS AND METHODS: The right femoral arteries of anaesthetised female pigs were clamped. Twelve pigs were divided into 2 groups (n = 6 per group). In the treatment group, 5% of blood volume was venesected from the ipsilateral femoral vein upon reperfusion; the other arm served as control. The animals were sacrifi ced after 4 days for histological examination. A pathologist, blinded to the experimental groups, graded the degree of microscopic injury. RESULTS: For the control group, the kidneys showed glomeruli and tubular damage. The livers demonstrated architectural distortion with cellular oedema. There was pulmonary oedema as well as extensive capillary congestion and neutrophil infiltration. Such findings were absent or reduced in the venesected animals. Consequently, the injury scores for the kidney, lung, liver and heart were significantly less for the venesected animals. CONCLUSION: Selective venesection reduces the remote organ injuries of the ischaemic-reperfusion phenomenon.

Risk factors and presentation of deep venous thrombosis among Asian patients: a hospital-based case-control study in Singapore.

Deep venous thrombosis (DVT) is perceived to occur less frequently among Asians than Caucasians, although the reason for this has not been fully understood. Hence, there may be differences in risk factors and presentations among Asian patients compared to their Caucasian counterparts. This study examined the association of classical risk factors and presentations among Asian patients with DVT. We retrospectively reviewed 862 symptomatic patients referred to the vascular diagnostic laboratory in a hospital for suspected DVT over a 30-month period. Two hundred and seventy-seven patients (32.1%) tested positive for DVT on duplex ultrasound. After adjusting for age and gender, ethnicity was not a statistically significant demographic factor associated with DVT. Two hundred and seventy-one patients diagnosed as having DVT on ultrasound were matched for age, gender, and ethnicity to negative controls to study the significance of risk factors and presenting symptoms or signs. In multivariate analysis, independent risk factors for DVT included immobility (odds ratio [OR] = 2.61, 95% confidence interval [95% CI] 1.63-4.15], malignancy (OR = 1.77, 95% CI 1.01-3.10), and a history of thrombophilia (OR = 9.95, 95% CI 1.26-78.87). The significant forms of DVT presentation were limb swelling (OR = 2.53, 95% CI 1.41-4.54) and pulmonary embolism (OR = 11.45, 95% CI 3.23-40.59). Fever of more than 37.5 degrees C was a negative predictive factor (OR = 0.42, 95% CI 0.23-0.76). This study shows that the common risk factors of DVT such as surgery and fractures do not affect Asians as much as Caucasians. Instead, thrombophilia and underlying malignancy are prominent risk factors among Asians. Diagnosis of DVT in Asians based on clinical grounds can also be problematic as few presentations are specific.

Extensive upper-extremity venous thrombosis after fluorescein angiography.

PURPOSE: To report a case of extensive cephalic and basilic venous thrombosis after fluorescein angiography. DESIGN: Interventional case report. METHODS: A 38-year-old Chinese male presented with blurring of vision in his left eye. Clinical examination revealed central serous retinopathy, and a routine fluorescein angiography was performed. RESULTS: He developed inflammation over the right arm over 4 days. Duplex scan disclosed extensive superficial venous thrombosis of the right upper limb with occlusion of the basilic vein and cephalic vein in the proximal right upper arm to the level of the midarm. He was treated medically but was subsequently lost to follow-up. CONCLUSIONS: Extensive upper-extremity venous thrombosis is infrequent after single-shot intravenous cannulation. Venous thrombosis occurring after fluorescein angiography has not been reported up to this time. It is possible that proper arm positioning during the procedure may reduce this risk, and ophthalmologists should be vigilant of this potentially unusual complication.