Placenta Accreta New Detection Procedure by Rapid Assessment of Serum BNP
Condition: Placenta Accreta; Placenta Previa; Normal Pregnancy
MeSH terms: Placenta Accreta; Placenta Previa
Study type: Observational [Patient Registry]

Summary: 
      The placenta accreta is defined as a placenta that is abnormally adherent to the myometrium.
      It can thus invade the entire thickness of the myometrium (placenta increta) or even exceed
      the serosa and invade neighboring organs (placenta percreta). It is a rare obstetric
      pathology with significant morbidity, and its management most often requires hemostatic
      hysterectomy. Its frequency has increased significantly in recent decades due to the
      increased rate of caesareans.

      The maternity center of Tunis ( CMNT ) is a level 3 maternity center, supporting over 12 000
      births yearly, where the caesarean section's rate is very high, close to 45% of deliveries.
      Recently we noted an increase in abnormal placental invasion incidence : in 2018, we report
      over 60 cases of placenta accreta,increta and percreta.

      Early detection of these patients can help reduce potential risks. Ultrasound and MRI are the
      main diagnostic tools, but each one has weaknesses. Biological approch of this diagnosis is
      not well studied. Recently, BNP has been shown to be associated with increased angiogenesis.
      Because placenta accreta is characterized by abnormal uteroplacental neovascularization, it
      has been hypothesized that serum BNP levels may be related to abnormal invasion of the
      placenta.

      In the literature, only one study investigated the relationship between cardiac biomarkers
      (Pro-BNP, CK, CK-MB and troponins) and abnormalities of placental adhesion. The main
      conclusion was that the Pro-BNP could predict placental accretisation.

      Thus, the BNP as a mean of screening, could enrich our diagnostic arsenal. The purpose of our
      study is to determine whether or not BNP can predict abnormal placental invasion during
      pregnany.
    

Detailed description: 
      The investigators will conduct a monocentric , prospective, observational study, including 60
      pregnant women, with history of at least one previous uterine scar, and scheduled for
      cesarian delivery. The participants will be divided into 3 equal groups according to the
      imaging data obtained by a senior ultrasonographer , and the MRI data when necessary :

      Ultrasonography will be performed in all participants. If placenta previa is diagnosed,
      without any suggestive signs of abnormal placental invasion, the patient is assigned to group
      P.

      If placenta previa is diagnosed, and associated to suggestive signs of abnormal placental
      invasion,the patient is assigned to group I and an MRI will be performed.

      If the ultrasonography is free of any suggestive signs of placenta previa, the patient is
      assigned to group N.

      Finally :

        -  group P : pregnant women with placenta previa on ultrasound and no suggestive signs of
           abnormal placental invasion

        -  group I : pregnant women with placenta previa on ultrasound, and suggestive signs of
           abnormal placental invasion on ultrasound .

        -  group N : pregnant women without suggestive signs of placenta previa or abnormal
           placental invasion on ultrasound

      After written and informed consent are obtained, a standard battery of blood tests including
      serum BNP will be runned.

      For every patient, the following will be recorded : anthropometric measurements, previous
      obstetric and medical history, emergency or elective surgery, anesthetic technique,
      per-operative findings (placenta previa, placenta previa with abnormal placental invasion
      (accreta, increta, percreta), placenta normally located), amount of blood products
      transfused, nature of haemostasis procedures, complications.

      Patients will be excluded, if their condition may cause a rise in serum BNP during the sample
      collection, those being: preterm premature rupture of membranes, acute anaemia or
      metrorrhagia, active labor, severe infections, arterial hypertension, known pulmonary
      hypertension, symptoms of heart failure, known hypertrophic or restrictive cardiomyopathy,
      history of valvular or congenital heart disease, atrial and ventricular tachyarrhythmias,
      pulmonary embolism, chronic obstructive pulmonary disease, kidney failure or renal
      dysfonction, liver dysfonction, severe metabolic and hormone abnormalities ( thyrotoxicosis
      or diabetic ketosis ), drug use possibly affecting cardiovascular system ( beta-blocker or
      other cardiovascular drug).

      ANESTHETIC MANAGEMENT:

      The timing of delivery is usually between 36 and 37 weeks for group P and I, and after 38
      weeks for group N.

      General anesthesia will be performed in pregnant women from group I and P. Regional
      anesthesia will be performed in pregnant women from group N.

      Hemodynamic management during anesthesia for group I will require placement of 2 peripheral
      large-bore venous access, a desilet catheter in the femoral vein, and an arterial line
      preoperatively.

      In patients from group P, 2 peripheral large-bore venous access will be placed
      preoperatively. A desilet catheter and arterial line will be obtained if necessary upon the
      anesthesiologist judgment.

      In patients from group N, 1 peripheral large-bore venous access will be placed prior to the
      beginning of surgery.

      Blood transfusion requirements will be based on the hemodynamic status, the amount of blood
      loss, the need of catecholamines and the anesthesiologist's experience.

      Peroperatively, final diagnosis will be made according to surgical findings. If placenta is
      completely and easily removed, the diagnosis of abnormal placental invasion will not be
      retained.

      If placenta could not be easily and completely removed, the diagnosis of abnormal placental
      invasion in established, and the case is carried out according to our surgical and anesthetic
      standards of management.

      After collecting all groups, blood samples will be analysed for BNP, in a unique serie of
      tests.
    

Intervention name(s): serum BNP assessment
Intervention type(s): Diagnostic Test
Intervention description(s): serum BNP assessment in pregnant women with placenta previa, associated or not to a suspected abnormal placental invasion, compared to a control group
Observational model: Case-Control
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        60 parturients free from any exclusion criteria , devided equally into 3 groups :

          -  group P : parturients with placenta previa on ultrasound and no suggestive signs of
             placenta accreta

          -  group A : parturients with placenta previa on ultrasound, and suggestive signs of
             placenta accreta on ultrasound and / or MRI

          -  group C : parturients without suggestive signs of placenta previa or accreta on
             ultrasound
      
Biospecimen description: 
      blood serum
    
Keywords: placenta previa; placenta accreta; BNP; cesarean section; pregnancy