Platelet-rich plasma (PRP) is an autologous concentration of human platelets in a small volume of plasma.

Because it is an autogenous preparation, PRP is inherently safe and therefore free from concerns over transmissible diseases such as HIV and hepatitis.

Its power of regeneration already proved by orthopedics and dentists in their trials to regenerate cartilages .We will use it to know its ability to enhance healing of sternum in vulnerable patients to sternal dehiscence after open heart surgery .

1. INTRODUCTION Successful healing of the sternum after open heart surgery is a complicated phenomenon because of the natural body ability often fails to efficiently repaired of the sternum in patients after open cardiac surgery (Everts 2006). Recent evidence based data suggested new modalities to increase the quality and accerelate sternal healing in high risk patients after open heart surgery vulnerable for early sternal dehiscence (Liu 2002) . PRP considers as an attractive alternative option in that manner. Marx and associates demonstrated the positive influence of PRP on bone regeneration and healing since 1998 (Marx 1998 ) . Autologous PRP carries minimal risk of infectious diseases transmission, immunologic reactions, and rejection. PRP with concentrations 4 to 5 folds of the normal average platelet (1,100,000 platelets/μl ) proved to have a remarkable increase in bone mineral density and regeneration . the market for PRP grows from $45 million in 2009 to more than $120 million by 2016 (Dawood 2018 ). Multiple factors affect the PRP efficacy in sternal bone healing and regeneration process. Platelet preparation before surgical application is an area of concern with PRP. For this issue, an appropriate anticoagulant must be used to prevent the early spontaneous activation of the platelets (Kassolis 2000 ). Several anticoagulants have been employed for PRP preparation including heparin, citrate, acid-citrate-dextrose solution A or anticoagulant citrate dextrose-A ,citrate-phos phate-dextrose ,citrate-theophylline-adenosine- dipyrimadole and ethylene diamine tetra- acetic acid moreover, several manual or automated systems have been designed for preparing PRP including clinical laboratory methods and kits (Carlson 2002). PRP produced by single- or double-step centrifugation technology via platelet-pheresis (autologous selective filtration )and the cell separators,However, these methods are rarely used nowadays, due to several factors including high cost, large volume of peripheral blood should be harvested from the patients, and potentially damage to the platelet (Dhurat 2014) . Commercially available PRP kits and devices differ in ease of use, one or two step centrifugation protocols, centrifugation speed, final PRP volume, platelet count and activation, platelet and growth factor concentrations, and final RBCs' and WBCs' count.Nevertheless, the cost of the commercial kits for PRP processing is still a challenge (Trebinjac 2020) .

2. AIM/ OBJECTIVES :

   To study the Effect of platlet rich plasma on sternal healing post median sternotomy in Patients undergoing open heart surgery

3. METHODOLOGY:

   • Type of Study: prospective clinical trial propensity matched comparative study

   • Study Setting: Patients refered to our Cardiothoracic department, Faculty of medicine, Ain Shams University and ain shams specialized hospital to perform open heart surgery who fulfill our inclusion charateria.

   • Study Period: It will be performed between march 2020 and january2022

   • Study Population:

     - Inclusion Criteria: Patients with one of which

     1. patients will under go open heart surgery with BMI >30 or
     2. diabetic patients
     3. patients with history of chest wall radiotherapy exposure or
     4. bilateral internal mammary artery harvesting .
     5. age > 70 years old -Exclusion Criteria:
     1. patient with history of open heart surgery
     2. patients with preoperative HB level <11
     3. All emergency and urgency cardiothoracic surgery

   • Sampling Method: prospective clinical trials propensity matched comparative study.

   • Sample Size: 50 patients

   • Ethical Considerations: All the patients will sign an informed consent for operation and for being involved in the research and follow up process .

   • Study Tools: platlets rich plasma

   • Preparation technique : ultra centrifuge technique

   • Study Procedures:

Patient data will be collected preoperatively and intraoperatively and these risk factors will be studied Patients will be distributed to two equal groups. Demographic data : Age - gender - weight - BMI-DM-hist. of radiotherapy exposure -BIMA

Intraoperative :

We will apply 10cm plasma contain 1 million platlets on the sternal edge of only one group of them before sternal closure.

post-operative The patients will be followed till being discharged from hospital and after the first 3 months after surgery sternal stability and absence of dehiscence will be primary out come measure

Secondary end point :

Severe form of sternal deheiscence After 3months: stability of sternum will be assessed By CT chest with 3D bone reconstruction and the value of bone density as aconfirmatory test

• Statistical Analysis:using the arithmetic mean, standard deviation using hypothesis student's "t" tests for quantitative data analysis, while qualitative data (ordinal, categorical) will be analyzed using The chi-square test (x2) (Fisher's Exact Test). For all statistical comparisons, a P value of <0.05 will be considered significant and a P value of <0.01 will be considered highly significant.
• Statistical Package:Data will be statistically analyzed using statistical package of social science (SPSS)

Inclusion Criteria:

• Patients with one of which

  1. patients will under go open heart surgery with BMI >30 or
  2. diabetic patients
  3. patients with history of chest wall radiotherapy exposure or
  4. bilateral internal mammary artery harvesting .
  5. age > 70 years old

Exclusion Criteria:

• patient with history of open heart surgery 2- patients with preoperative HB level <11 3-All emergency and urgency cardiothoracic surgery

planning to make IPD available to other researchers

data will be available after 3 YEARS and for 2 years.

IPD sharing access criertia including clinical researcher cardiac surgeons postgraduate investigator