Interventional Radiology And Cardiology

Glimpse about Interventional Radiology And Cardiology

1. INTERVENTIONAL RADIOLOGY AND CARDIALOGY By M. Vharshini 4 th year Biomedical Sciences

2. Introduction Interventional Radiology is a medical subspecialty of radiology. It provides minimally invasive diagnosis and/or treatment using imaging to target and show the results of the intervention. Interventional Cardiology is the subspecialty of cardiology that uses intravascular catheter-based techniques with fluoroscopy to treat various heart diseases.

3. Interventional Cardiology and Radiology Procedures Radiofrequency ablation Coronary artery angioplasty and stent placement Transjugular intrahepatic portosystemic shunt (TIPS) placement Coronary angiography

4. Cardiac Radiofrequency Ablation Radiofrequency ablation (RF ablation) is a minimally invasive treatment for cancer that is approved by the FDA. It is used to treat primary lung cancers, liver and kidney cancer and to manage pain resulting from small bone cancers. RFA utilizes frictional energy transmitted by oscillating ions within tissue to heat and treat tumors.

5. PRINCIPLE: Cells undergo coagulation necrosis when heated to more than 50°C for more than 5 minutes. At temperatures above 60 ° C, intracellular proteins are denatured (killed) rapidly. The AC current (350-500 kHz) of RF waves passing down from an un-insulated electrode tip into the surrounding tissues generates changes in the direction of ions and creates ionic agitation and frictional heating.

6. The tissue heating then dehydrates the tissue, resulting in tissue destruction by coagulative necrosis . Cell membranes are destroyed through dissolution and the melting of lipid bilayers , and lastly, cell death is inevitable.

7. EQUIPMENT: The RF ablation setup is a simple electrical circuit wherein the current loop comprises a generator, cabling, electrodes and tissue as the resistive element. Catheter: Single (monopolar) electrode radiofrequency catheters emit radiofrequency energy from a single point at the catheter tip.

8. Multi electrode radiofrequency catheters have several electrodes, each of which can deliver radiofrequency energy. These catheters can ablate a larger area of tissue than single point radiofrequency energy catheters, which could decrease procedure time. These catheters can also deliver superficial bipolar radiofrequency energy, which my reduce injury to deeper tissues in certain areas of the heart.

9. Irrigated tip catheters: Closed Irrigation: Saline is perfused via a pump mechanism through the catheter tip, turns around within the catheter tip, and returns back to the pump. Open Irrigation: Open irrigation overcomes the limitations of non-irrigated ablation by lowering electrode and tissue surface temperature. The efficacy of power delivery is increased along with the safety of reduced char formation.

10. Three types of RF electrodes are currently available commercially : Two brands of Multi polar retractable needle electrodes: RITA Medical Systems , Mountain View, CA; LeVeen needle electrode , Boston Scientific, Boston, MA Internally cooled electrode: Cool-Tip RF electrode ; Radionics , Burlington, MA

11. Generator and ground pads: The RF ablation generator provides three essential functions: power generation, control, and user interface. The ground pad closes the electrical current path and is designed to disperse energy over a large surface area to reduce the likelihood of thermal injury to the skin.

12. WORKING: The procedure can be done in a variety of ways. RFA can be performed percutaneously . In this technique, under ultrasound guidance the LeVeen ® Electrode is inserted through a small puncture in the chest and positioned within the tumor and opened allowing the multiple tines to spread out.

13. Then, the generator is turned on and the radiofrequency energy is passed from the tines of the electrode into the tumor. The energy creates heat which destroys the cells in the area. The result is destruction (ablation) of the tumor.

14. APPLICATIONS: RF ablation is used in recurrent atrial flutter (AFL), atrial fibrillation (AF), Supraventricular Tachycardia (SVT). It is used in the treatment of varicose veins . RFA is used to treat severe chronic pain the lower (lumbar) back. RFA is also used in radio frequency lesioning, for vein closure in areas where intrusive surgery is contraindicated by trauma. RFA is used in liver resection to control bleeding (homeostasis) and facilitate the transaction process. RFA is also used to ablate tumors in patients where surgery is not possible due to health condition.

15. Coronary Angioplasty And Stent Placement Coronary angioplasty is a procedure used to open blocked coronary arteries (caused by coronary artery disease). It restores blood flow to the heart muscle without open-heart-surgery. Coronary angioplasty is also known as Percutaneous transluminal coronary angioplasty (PICA). The combination of coronary angioplasty with stenting is usually referred to as Percutaneous Coronary Intervention ( PCI).

16. EQUIPMENT: The most commonly used PCI equipment consists of four basic elements: a guiding catheter, a balloon catheter, a coronary guidewire, a stent.

17. Guiding Catheter: A special large lumen catheter is used to deliver the coronary balloon catheter and other interventional devices to the vessel that contains the lesion to be dilated. Function: A guiding catheter serves three major functions during angioplasty: Balloon/Stent catheter delivery and guidance Backup support for balloon/Stent advancement Pressure monitoring and contrast injections (1)Stiffer body ( 2)variable softer primary curve (3) wire braiding (4) atraumatic tip (5) large lumen(6) lubrious coating 

18. Balloon Dilatation Catheter System: When a  stent  is placed inside of a coronary artery, it acts as a support or scaffold, keeping the vessel open. Stent  procedures are usually used along with balloon catheters. There are three types of PCI balloon catheters: Over-the-wire (OTW) Monorail Fixed-wire

19. Stents: A Stent is a tiny, expandable, metal mesh coil that is put into the newly-opened area of the artery to help keep the artery from narrowing or closing again. It helps re-narrowing of the blood vessel.

20. PROCEDURE: PCI uses fluoroscope to find the blockages in the coronary arteries as a contrast dye moves through the arteries. The step by step procedure of percutaneous coronary intervention: The artery is filled with atherosclerotic material, compromising the lumen. A guidewire is positioned past the stenosis through the lumen A balloon catheter is advanced over the guidewire

21. The balloon is inflated The balloon catheter is exchanged for a stent (on a balloon) The stent is expanded The expanded stent remains in place after the deflated balloon is withdrawn.

22. APPLICATIONS: Percutaneous coronary intervention (PCI) is used to treat narrowing (stenosis) of the coronary arteries of the heart found in coronary artery disease.

23. Transjugular Intrahepatic Portosystemic Shunt (TIPS) Transjugular Intrahepatic Portosystemic Shunt (TIPS) is a procedure that uses imaging guidance (fluoroscopy) to percutaneously create connection between the portal and systemic circulations within the liver . A TIPS is placed to reduce portal pressure in patients with complications related to portal hypertension. TIPS connects the vein which brings blood from the gastro-intestinal tract and intra abdominal organs to the liver, and the vein from the liver to the right part of heart.[

24. EQUIPMENT: In this procedure, x-ray or ultrasound equipment, a stent, and a balloon-tipped catheter are used. The equipment used for this examination consists of Radiographic table, one or two x-ray tubes and a television like monitor that is located in the examining room. Fluoroscopy, which converts x-rays into video images, is used to watch and guide progress of the procedure.

25. A catheter is a long, thin, plastic tube that is approximately 1/8 inch in diameter. The Stent used in this procedure is a small wire mesh tube , often covered with a fabric made of GORE-TEX®. Other equipment that may be used during the procedure includes an intravenous line ( IV), ultrasound machine and devices that monitor heart beat and blood pressure

26. PROCEDURE: With the use of Fluoroscopy guidance and an injection of contrast material containing iodine, the location of the hepatic vein is identified. From the hepatic vein, a connection through the liver is made into the portal vein using guiding catheter. Once the connection is made to the portal vein, fluoroscopy guidance is utilized to dilate the connection and place a stent

27. APPLICATION: The TIPS procedure is usually performed in patients with liver cirrhosis . The TIPS may successfully reduce internal bleeding in the stomach and esophagus in patients with cirrhosis.

28. Coronary Angiography An angiogram is an x-ray image of blood vessels after they are filled with a contrast material. An angiogram of the heart, a coronary angiogram, is the “Gold Standard” for the evaluation of coronary artery disease (CAD). A coronary angiogram can be used to identify the exact location and severity of CAD.

29. EQUIPMENT : The equipments needed for coronary angiogram are Angiogram needle, vascular sheath, Guidewires, Catheters, Fluoroscopic machine, Power injector The catheter inserted into angiogram needle.

30. PROCEDURE: Coronary angiography is performed with the use of local anesthesia and IV sedation, and is generally not significantly uncomfortable. In performing a coronary angiogram, a small catheter is inserted through the skin into an artery in either the groin or the arm.

31. Under fluoroscopy guidance, the catheter is then advanced to the opening of the coronary arteries. A small amount of radiographic contrast, is injected into each coronary artery. The images that are produced are called angiogram After the procedure, the catheter is removed and the artery in the leg or arm is sutured, sealed to prevent bleeding

32. APPLICATION: Coronary Angiography procedure is used to diagnose coronary heart disease and coronary micro-vascular disease after chest pain, sudden cardiac arrest, or abnormal results from tests such as an electrocardiogram (EKG) of the heart or an exercise stress test.

33. Bibbliography Yasunori Minami and Masatoshi Kudo , “Radiofrequency Ablation of Hepatocellular Carcinoma: A Literature Review,” International Journal of Hepatology , vol. 2011, Article ID 104685, 9 pages, 2011. doi:10.4061/2011/104685 http://www.rfalung.com/rfa_brochure.pdf

34. Thank you!