Thrombosis in small and medium-sized pulmonary arteries in Wegener s granulomatosis: A confocal laser scanning microsc

1. Thrombosis in small and medium-sized pulmonary arteries in Wegener�s granulomatosis: A confocal laser scanning microscopy studyJ Bras Pneumol.2010;36(6):724-730 Lisa Lewis

2. Wegener�s Granulomatosis (WG) Multi-system disease Inflammation of the blood vessels which affects blood flow to organs/tissues causing damage Respiratory tract & kidneys mainly affected Cause unknown � auto-immune � ANCA (Anti-neutrophil cytoplasmic antibodies) Over 90% of patients with WG exhibit ANCA Response to immunosuppressive therapy supports auto-immune link

3. Wegener�s Granulomatosis (WG) Diagnosis based on clinical features, raised ANCA titre, histopathology FBC, ESR, ANCA, renal function tests, chest X-ray, CT scan, lung biopsy, kidney biopsy Early diagnosis important so early treatment can prevent pulmonary & renal damage Aggressive immunosuppressive therapy required If untreated 80% of patients die within 1 year, mean survival 6 months

4. Diagnostic Techniques for WG

5. INTRODUCTION WG � ANCA-associated vasculitis causing inflammation and necrosis of small and medium-sized arteries Severe clinical presentation commonly seen � kidney failure & lung haemorrhage Thromboembolic events have only recently been seen in WG patients Few histopathological findings of thrombi in patients with ANCA-associated vasculitis Study conducted to determine presence of fibrin thrombi in pulmonary arteries using confocal laser scanning microscopy

6. AIMS OF STUDY To study pulmonary microcirculation � small & medium-sized pulmonary arteries in patients with WG To quantify fibrin thrombi in pulmonary arteries of patients with WG To provide evidence for benefit of anticoagulant therapy in treatment of patients with WG

7. METHODS All patients tested to diagnose pulmonary diseases All patients had abnormal chest X-ray & abnormal lung biopsy & positive ANCA 6 patients diagnosed with WG 4 patients without WG (control group) 4 arteries were analyzed in each patient (24 WG & 16 control samples) Calculated size of three main areas of vessel total vessel area / free lumen area / thrombotic area Calculated the thrombotic index (thrombus area divided by the total vessel area as a percentage)

8. METHODS Endothelial cell marker CD34 and confocal laser scanning microscopy used to detect intravascular fibrin thrombi Tissue sections incubated with monoclonal antibody Anti-CD34 Sections were revealed with a secondary antibody linked to fluorescein isothiocynate Sections mounted with an aqueous mounting medium A confocal laser scanning microscope with three lasers, magnification of x40 & fluorescence microscope Argon (488 nm), HeNe1 (543 nm), HeNe2 (633 nm) used to obtain 1 mm thick serial images of each vessel

9. RESULTS Mean total vessel area was similar in WG and non-WG groups Thrombi present in 92% of 24 WG patient samples and in 0% of the 16 non-WG patient samples Mean thrombotic area significantly greater in WG group than non-WG group Mean free lumen area significantly smaller in WG group than non-WG group Mean vessel wall area significantly larger in WG group than non-WG group

10. RESULTS

11. RESULTS

12. CONCLUSIONS Confocal laser scanning microscopy revealed a significant association between pulmonary microvascular thrombosis and WG Microvascular thrombosis may play a role in pathophysiology of pulmonary WG Thrombosis may cause strokes, deep vein thrombosis (DVT), pulmonary embolisms (PE) in WG patients Anti-coagulant therapy could be used - to treat thrombosis in patients with pulmonary WG - as prophylaxis of thromboembolism in WG patients - as an anti-inflammatory therapy

13. CONCLUSIONS Study has limitations Sample size small Only small & medium-sized pulmonary arteries studied No coagulation studies performed Further studies needed to confirm findings Randomised clinical trials needed to test role of anticoagulant therapy in these patients