title: Risk stratification, systematic classification, and anticipatory management strategies for stent fracture after percutaneous pulmonary valve implantation.
abstract: BACKGROUND
  We analyzed the incidence, risk factors and treatment options for stent fracture after percutaneous pulmonary valve (PPV) implantation (PPVI).
  
  
  RESULTS
  After PPVI, 123 patients had chest x-ray in anteroposterior and lateral projection, echocardiography, and clinical evaluation during structured follow-up. Of these 123 patients, 26 (21.1%) developed stent fracture 0 to 843 days after PPVI (stent fracture-free survival at 1 year, 85.1%; at 2 years, 74.5%; and at 3 years, 69.2%). Stent fracture was classified as type I: no loss of stent integrity (n=17); type II: loss of integrity with restenosis on echocardiography (n=8); and type III: separation of fragments or embolization (n=1). In a multivariate Cox regression, we analyzed various factors, of which 3 were associated with a higher risk of stent fracture: implantation into "native" right ventricular outflow tract (P=0.04), no calcification along the right ventricular outflow tract (judged with fluoroscopy, P=0.02), recoil of PPV (qualitatively, PPV diameter in frontal or lateral plane with fully inflated balloon > diameter after balloon deflation, P=0.03). Substernal PPV location, high-pressure post-PPVI dilatation of PPV, pre-PPVI right ventricular outflow tract gradients, and other indicators of PPV compression or asymmetry did not pose increased risk. Patients with type I fracture remain under follow-up. Patients with type II fracture had 2nd PPVI or are awaiting such procedure, and 1 patient with type III fracture required surgical explantation.
  
  
  CONCLUSIONS
  Stent fracture after PPVI can be managed effectively by risk stratification, systematic classification, and anticipatory management strategies. Serial x-ray and echocardiography are recommended for surveillance.
authors.affiliation: University College London Institute of Child Health and Great Ormond Street Hospital for Children, Great Ormond Street, London WC1N 3JH, United Kingdom.
authors.forename: Johannes
authors.initials: J
authors.lastname: Nordmeyer
authors.forename: Sachin
authors.initials: S
authors.lastname: Khambadkone
authors.forename: Louise
authors.initials: L
authors.lastname: Coats
authors.forename: Silvia
authors.initials: S
authors.lastname: Schievano
authors.forename: Philipp
authors.initials: P
authors.lastname: Lurz
authors.forename: Giovanni
authors.initials: G
authors.lastname: Parenzan
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Taylor
authors.forename: James E
authors.initials: JE
authors.lastname: Lock
authors.forename: Philipp
authors.initials: P
authors.lastname: Bonhoeffer
mesh_terms: D000293:Adolescent; D004452:Echocardiography; D005260:Female; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects* / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D008297:Male; D011183:Postoperative Complications / Q000145:classification / Q000453:epidemiology / Q000628:therapy; D016016:Proportional Hazards Models; D011475:Prosthesis Failure; D011664:Pulmonary Valve / Q000002:abnormalities / Q000601:surgery; D011665:Pulmonary Valve Insufficiency / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000601:surgery*; D012189:Retrospective Studies; D012307:Risk Factors; D015607:Stents / Q000009:adverse effects* / Q000706:statistics & numerical data; D018497:Ventricular Dysfunction, Right / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000601:surgery