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Disorders of the arterial system

Disorders of the arterial system. Dr. Amanj Kamal F.I.C.M.S. Cardiovascular Surgery. Turn the mobile off. Questions at the end. Anatomy. Main function of the arteries. Sizes; L, M, S. and Arteriols Wall composition according to sizes. (more elastic in large ones). Collaterals .

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Disorders of the arterial system

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  1. Disorders of the arterial system Dr. Amanj Kamal F.I.C.M.S. Cardiovascular Surgery

  2. Turn the mobile off Questions at the end

  3. Anatomy • Main function of the arteries. • Sizes; L, M, S. and Arteriols • Wall composition according to sizes. (more elastic in large ones)

  4. Collaterals • They are; • Most organs got it • Some not, (heart, kidney, retina). End arteries. • Eg. Subclavian artery • Time and chronicity

  5. Physiology Lamina

  6. Intima as organ? 1%, surface area • Growth promotion and inhibition, • Vasoconstriction and vasodilation, • Blood cell adherence and nonadherence, • Anticoagulation and procoagulation. Smooth muscle cells • Major bulk • Mechanical and structural support • Proteoglycans.

  7. Maintenance of vascular tone. Nitric oxide (NO), oxygen free radicals, endothelins, angiotensins • Coagulation. Protien S, factor V, tissue factor, plasminogen activators (and inhibitors)(PAs)(PAIs) • Inflammatory and immunologic response. The process of cell adherence, cell activation, and cell migration • Vascular wall modeling. platelet-derived growth factor (PDGF), and insulin-like growth factor 1 (IGF-1).

  8. Arterial Substitutes

  9. Introduction • Last 5o years of increased vascular surgery. • In US: 350,000 synthetic, 200,000 autogenous vein/yr.

  10. The optimal arterial substitute should be: • Strong, inexpensive, and lasting for the life of the patient; • Easily and permanently attachable to the host vessel; • Biocompatible, and nonthrombogenic luminal surface; • Resist infection; • Available in appropriate sizes; • Remain patent without intervention; • Have viscoelastic properties similar to those of a normal artery.

  11. The optimal arterial substitute should not: • Leak blood or serous fluid • Degenerate chemically or physically with time; • Undergo abnormal proliferative response • Promote thrombus formation or be a source of emboli • Occlude when flexed. • Damage blood components.

  12. Arterial substitute evaluation • Primary patency, • Secondary patency, • Assisted primary patency, effectiveness of follow up.

  13. Allografts

  14. Arterial allografts • Were the first widely used. • Early results were encouraging. • viability was not essential for successful grafting. • With ages (few yr.s loss of collagen, elastin …) • Disappointing long term. • High incidence of compoications. (abandond)

  15. Saphenous Vein Allografts • Human cadavers. • Antigenic; immunologic rejection response • Cryopreservation alone. • Advances in immunosuppression • No significant clinical application

  16. Umbilical Vein Allografts • From human umbilical cords. • Glutaraldehyde, ethanol, polyester mesh tube. • High pressure and nonantigenic. • Patency rates of 70% and 50% at 1 and 5 years. • Degenerative changes, aneurysms, difficult to implant, • No longer

  17. Xenografts

  18. Xenografts • Unmodified arterial xenografts 1950s • Prominent immunologic reaction • Treating bovine carotid arteries • Modified xenografts 1960s • Poor long-term patency rates, 40% 3 to 6 years • aneurysms occurred in 3% to 6% • infection rate of 3% to 7% • Hemodialysis

  19. Autografts

  20. Arterial Autografts • Advantages: no infection, flexible, no aneurysm, blood supply, … • Disadvantage: short • CABG • Radial and internal mammary • Patency rate. And spasm. • Internal iliac artery for renal.

  21. Venous Autografts • Most successful and most clinically used. • Saphenous vein, cephalic and brachial veins, and superficial femoral and internal jugular veins • GSV; 70-80 cm, from to, valves, caliber… • Types; Reverse, and In situ. • patency of reversed 80-90% at 1 year, 55-86% at 5 years • reversed vein grafting is applicable to larger numbers of patients, • Occur; clamp stenosis, valve fibrosis, narrow anast.

  22. Prosthetic grafts

  23. Textile Grafts • Concept of :Mesh fabric would result in similar healing • Woven and knitted. • Major differences • Porosity • Preclotting

  24. Polytetrafluoroethylene (PTFE) Grafts • Flexible • All sizes • For extra anatomical bypass.

  25. So grafts’ types: • Allografts: - Artery - Saphenous vein - Umbelical vein • Xenografts: • Autografts: - Artery - Vein • Prosthetic grafts - Textile - PTFE

  26. Complications of Prosthetic Grafting • Anastomoticneointimal hyperplasia, • Graft infection, • Graft failure caused by fiber disruption or stretching, • Perigraftseromas, • Anastomotic false aneurysms.

  27. PTFE

  28. PTFE

  29. Dacron

  30. Dacron

  31. Dacron

  32. Graft infection

  33. Any questions?

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