title: Assessment of IVC filter efficacy in prevention of pulmonary thrombo-embolism by 99mTc-MAA lung perfusion scintigraphy--a case series and review of literature.
abstract: BACKGROUND
  Anticoagulant therapy is the standard treatment of venous thrombo-embolism (VTE). Permanent inferior vena cava (IVC) filter is an important adjunctive therapy in these patients to prevent the complications like potentially fatal pulmonary embolism and chronic thrombo-embolic pulmonary hypertension. We studied patients with proximal deep vein thrombosis (DVT) of lower limbs and recurrent pulmonary thrombo-embolism (PTE), who were put on permanent IVC filters for the prevention of further episodes of PTE. The efficacy of filters in prevention of PTE was assessed by clinical history and was supported by follow-up (99m)Tc-MAA lung perfusion scintigraphy.
  
  
  RESULTS
  We prospectively enrolled 7 patients of PTE, who were put on IVC filter from July 2002-April 2005. All patients had (99m)Tc-MAA lung perfusion scan before filter implantation. Percutaneous IVC filter placement in infra-renal position was done. All patients were put on adequate oral anticoagulant treatment with target INR of 2.0-3.0. At follow-up two patients died - one died of intractable right heart failure at 6 months and other died of carcinoma colon metastasis after 16 months. The mean follow-up of rest of five patients was 3.5 years (range 20-54 months), and none of them had clinically evident further episode of DVT or PTE. Their repeat lung perfusion scan at 1 year of follow-up showed marked improvement in perfusion with no evidence of additional fresh/new defects.
  
  
  CONCLUSIONS
  Follow-up (99m)Tc-MAA lung perfusion scan in PTE patients, who are on IVC filter, can demonstrate the significant improvement in lung perfusion secondary to prevention of further pulmonary embolism episodes and resolution of pulmonary thrombus by continued anticoagulant therapy.
authors.forename: Rajesh
authors.initials: R
authors.lastname: Vijayvergiya
authors.forename: Bhagwant Rai
authors.initials: BR
authors.lastname: Mittal
authors.forename: Anil
authors.initials: A
authors.lastname: Grover
authors.forename: Vuppaladadhiam
authors.initials: V
authors.lastname: Hariram
authors.forename: Anish
authors.initials: A
authors.lastname: Bhattacharya
authors.forename: Baljinder
authors.initials: B
authors.lastname: Singh
mesh_terms: D000328:Adult; D015150:Echocardiography, Doppler; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging* / Q000517:prevention & control*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D013668:Technetium Tc 99m Aggregated Albumin; D016896:Treatment Outcome; D016306:Vena Cava Filters
chemical_list: D019275:Radiopharmaceuticals; D013668:Technetium Tc 99m Aggregated Albumin