Thrombus Localization and Accompaying Disorders and Risk Factors
Condition: Pulmonary Embolism
MeSH terms: Pulmonary Embolism; Embolism
Study type: Observational

Summary: 
      ABSTRACT Pulmonary embolism shows a wide spectrum ranging from clinically asymptomatic
      thrombus to massive thrombus, leading to cardiogenic shock. The purpose of this study was to
      determine the association between thrombus localization and risk factors, accompanying
      disorders, D-dimer and the red blood cell distribution width (RDW) in patients with pulmonary
      embolism.
    

Detailed description: 
      Background Pulmonary embolism shows a wide spectrum ranging from clinically asymptomatic
      thrombus to massive thrombus, leading to cardiogenic shock. The purpose of this study was to
      determine the association between thrombus localization and risk factors, accompanying
      disorders, D-dimer and the red blood cell distribution width (RDW) in patients with pulmonary
      embolism.

      Material/Methods In 148 patients diagnosed with pulmonary embolism, the presence and
      anatomical localization of the thrombus were assessed with Computed tomographic pulmonary
      angiography. The accompanying disorders, risk factors, serum D-dimer, and the RDW in the
      patients were retrospectively evaluated.

      Background Pulmonary embolism (PE) is a serious cardiopulmonary disorder caused by partial or
      complete obstruction of the pulmonary arterial bed by a thrombus formed in systemic veins.
      Pulmonary embolism is thought to be a result of the interaction between the patient and risk
      factors 1-3. In case of suspected PE, clinical, laboratory, and radiological findings should
      be carefully studied. Since the clinical findings in PE are non-specific, objective
      diagnostic tests are required for the diagnosis 4. Computed tomographic pulmonary angiography
      (CTPA) is increasingly being used as the first investigation for suspected PE. The extent of
      PE is commonly expressed by indicating the anatomical level of the most proximal vessel
      affected by a thrombus 5. For the definite diagnosis of suspected PE, one of the tests to be
      used is the determination of the D-dimer level. Plasma D-dimer measurement provides
      information about fibrin-degradation fragment following fibrinolysis. D-dimer assays have low
      specificity, but high sensitivity and negative predictive value in most patients with
      suspected thromboembolism 6. The red cell distribution width (RDW) is a quantitative
      indicator of the size variability of red blood cells. This parameter can be easily obtained
      from a full blood count and is accepted as an indicator of ineffective red cell production 7.
      Some studies have suggested that RDW may be associated with cardiovascular and pulmonary
      diseases including PE 8-13.

      The purpose of this study was to determine the association between thrombus localization and
      risk factors, accompanying disorders, D-dimer and red blood cell distribution width (RDW) in
      patients with pulmonary embolism.

      Material and Methods Study design The data confirmed on 148 patients having PE by CTPA in the
      Clinic of Chest Diseases, Medical School, Yüzüncü Yıl University, Van, Turkey, in the period
      between January 2012 and August 2014 were retrospectively studied. The patients' accompanying
      disorders, risk factors, and the dosing of D-dimer performed on the same day of the CTPA and
      RDW levels were noted. The patients who had a story of hospitalising for reasons other than
      surgery such as Pneumonia, apses, brucella, encephalitis and the bedridden patients such as
      hemiplegia and long-term immobilised patients (>72 hours) after surgery were listed in the
      immobilisation group.

      Patients receiving the diagnosis of PE with no CTPA performed and 6 patients whose
      haemoglobin values were below 11 were not included in this study.

      Computed tomographic pulmonary angiography A thoracic CT scan was performed using a
      16-detector multi-sectional CT scanner (Somatom Emotion 16-slice; CT2012E-Siemens AG, Berlin
      and München-Germany) by injecting contrast agents intravenously, while the patient held her
      breath. Contrast-enhanced images were obtained 50-70 sec after IV administration of 120 ml of
      ionic iodinated contrast agent, iodiksanol (Visipaque 320 mg/100 ml, Opakim) using a power
      injector at a rate of 2 ml/sec.

      The parameters used were 120-130 (Kv), 80-120 (Ef-Mass), 0.6 sec (rotation time), 16 mm×1.2
      mm (acquisition), 1.2 mm (slice collimation), 5.0-3.0 (slice width), 0.80 (pitch factor), 5.0
      mm (increment), and 512×512 (matrix).

      D-dimer test The patients' blood specimens were evaluated in the Clinical Hematology
      Laboratory. The D-dimer levels were measured with a latex-enhanced photometric method ( Sta
      compact, Dade Behring, Marburg, Germany) using D-dimer kits.

      Red blood cell distribution width (RDW) The red cell distribution width (RDW) was determined
      in whole blood specimens. The hematological analysis was performed with a Coulter LH 750
      Complete Blood Count device (Beckman Coulter, Fullerton, California, USA).

      The study was planned according to the Declaration of Helsinki and rules of the Hospital
      Ethics Committee.

      Statistical analysis Descriptive statistics were presented with frequency and percent for
      categorical data, and with mean and standard deviation for numerical data. Comparisons
      between 2 independent groups were conducted with Mann-Whitney U test, and Chi-Square test for
      non-normally distributed numerical, and categorical variables, respectively. Pairwise Pearson
      correlation was executed to estimate linear relationship between characteristics. Receiver
      operating characteristic (ROC) curve analysis was utilized to determine the optimum cutoff
      level of the association of RDW with MPA. All statistical calculations were performed using
      SAS version 9.3 (SAS, 2014). The results were considered statistically significant when the p
      value was <0.05.
    

Intervention name(s): Pulmonary embolism
Intervention type(s): Radiation
Intervention description(s): the thrombus were assessed with Computed tomographic pulmonary angiography
Other intervention name(s): Red cell distribution width
Observational model: Case-Control
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        The data confirmed on 148 patients having PE by CTPA in the Clinic of Chest Diseases,
        Medical School, Yüzüncü Yıl University, Van, Turkey, in the period between January 2012 and
        August 2014 were retrospectively studied. The patients' accompanying disorders, risk
        factors, and the dosing of D-dimer performed on the same day of the CTPA and RDW levels
        were noted. The patients who had a story of hospitalising for reasons other than surgery
        such as Pneumonia, apses, brucella, encephalitis and the bedridden patients such as
        hemiplegia and long-term immobilised patients (>72 hours) after surgery were listed in the
        immobilisation group.

        Patients receiving the diagnosis of PE with no CTPA performed and 6 patients whose
        haemoglobin values were below 11 were not included in this study.
      
Keywords: Pulmonary embolism, Computed tomographic pulmonary