title: Platelet-to-lymphocyte ratio as a novel marker of in-hospital and long-term adverse outcomes among patients with acute pulmonary embolism: A single center large-scale study.
abstract: BACKGROUND
  The interaction of platelets with leukocytes is a well-known process both in progression and prognosis of acute pulmonary embolism (PE). Recently, platelet to lymphocyte ratio (PLR) is emerged as an indirect inflammatory indicator which was shown to be associated with adverse cardiovascular events in various clinical conditions, including acute PE. However, the long-term prognostic value of PLR in acute PE has not been investigated thoroughly. Therefore, we aimed to assess the impact of PLR on both in-hospital and long-term adverse outcomes in acute PE.
  
  
  METHODS
  A total of 459 patients with definite diagnosis of acute PE between January 2009 and January 2016 were enrolled. On admission, blood sampling to calculate PLR and detailed clinical data were obtained. Patients were divided into tertiles according to the admission PLR levels. Simplified PE severity index (sPESI) score and computerized tomography (CT) based pulmonary artery obstruction index were calculated for each patient.
  
  
  RESULTS
  Mean sPESI score of the study population was 1.6. A total of 34 patients (7.4%) died during index hospitalization. At median 28.8months follow-up, all-cause mortality was observed in 81 patients (1.9%). Patients in the highest tertile of PLR revealed a higher rate of in-hospital adverse events including cardiogenic shock, the necessity for thrombolytic therapy and in-hospital mortality as well as long-term all-cause mortality. In multivariate analysis, the PLR was found to be a significant predictor of both in-hospital adverse events (OR: 1.588, 95% CI:1.116-2.154, p=0.004) and long-term all-cause mortality (OR:1.746, 95% CI:1.211-2.865, p=0.001).
  
  
  CONCLUSIONS
  The PLR, as a simple, inexpensive and available marker of inflammatory and prothrombotic status, seemed to be a novel predictor of in-hospital and long-term adverse outcomes in patients with acute PE.
authors.affiliation: Turkey Yuksek Ihtisas Training and Research Hospital, Cardiology Department, Ankara, Turkey. Electronic address: dr.elifhande@gmail.com.
authors.forename: Elif Hande
authors.initials: EH
authors.lastname: Ozcan Cetin
authors.affiliation: Turkey Yuksek Ihtisas Training and Research Hospital, Cardiology Department, Ankara, Turkey.
authors.forename: Mehmet Serkan
authors.initials: MS
authors.lastname: Cetin
authors.affiliation: Hacettepe University Faculty of Medicine, Department of Cardiology, Ankara, Turkey.
authors.forename: Ugur
authors.initials: U
authors.lastname: Canpolat
authors.affiliation: Turkey Yuksek Ihtisas Training and Research Hospital, Cardiology Department, Ankara, Turkey.
authors.forename: Ahmet
authors.initials: A
authors.lastname: Akdi
authors.affiliation: Turkey Yuksek Ihtisas Training and Research Hospital, Cardiology Department, Ankara, Turkey.
authors.forename: Dursun
authors.initials: D
authors.lastname: Aras
authors.affiliation: Turkey Yuksek Ihtisas Training and Research Hospital, Cardiology Department, Ankara, Turkey.
authors.forename: Ahmet
authors.initials: A
authors.lastname: Temizhan
authors.affiliation: Turkey Yuksek Ihtisas Training and Research Hospital, Cardiology Department, Ankara, Turkey.
authors.forename: Sinan
authors.initials: S
authors.lastname: Aydogdu
mesh_terms: D000208:Acute Disease; D000368:Aged; D001792:Blood Platelets / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D017052:Hospital Mortality; D006801:Humans; D008214:Lymphocytes / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D011651:Pulmonary Artery / Q000473:pathology; D011655:Pulmonary Embolism / Q000097:blood / Q000175:diagnosis* / Q000401:mortality / Q000473:pathology
keywords: Platelet-to lymphocyte ratio; Prognosis; Pulmonary embolism