Cardiac Catheterization and Angiography
Heart and Coronary Vessels
Vessels that supply heart’s muscle tissue are called “coronary vessels”. Atherosclerosis is formation of plagues (produced by fatty accumulation and calcification) in the blood vessel wall. These plagues may result in obstruction or stenosis of the vessels. Stenosis or obstruction of coronary arteries might cause chest pain and heart attack (myocardial infarction) in the patient.
The basic principle to prevent stenosis of coronary arteries is to improve risk factors.
Measures are the essential for treatment, e.g. regular checks of diabetes mellitus, loss of weight, treatment of hypertension, improvement of high cholesterol and triglyceride values, cessation of smoking, and regular exercises.
Coronary Angiography and Cardiac Catheterization
Despite preventive measures taken, if complaints are present suggesting stenosis of coronary arteries, or if any abnormalities are detected by pre-tests (e.g. effort test, thallium test, etc.), cardiac catheterization and coronary angiography are performed to identify location and size of this stenosis. In case the stenosis is critical, the treatment options can be balloon angioplasty-stent or bypass operation. Both of these treatment options are performed safely in our day.
Cardiac catheterization is a diagnostic method that has been used for people since 1930s, and has been widely utilized since 1953. At the present time femoral artery is often used while arm vessels are rarely used. Cardiac catheterization and coronary angiography are diagnostic methods not treatment. It is based on imaging of cardiac cavities and coronary arteries with injection of contrast material and also measuring the pressure of the cardiac cavities and associated vessels.
The patient is delivered a tranquilizer and transferred to catheter laboratory after signing informed consent form. Femoral or arm section is anaesthetized to place a cannula in the vessel. The thin catheter made of plastic-like material is guided through cardiac cavities first to record the pressure then contrast material is injected for taking pictures. Then coronary arteries are displayed and recorded. This procedure takes approx 15 -30 minutes.
The First Few Hours After The Procedure
The cannula in the groin is removed after completion of procedure; compression is applied on the relevant area for 15 to 20 minutes. A tight bandage is placed after bleeding has stopped. Also, a sand bag of 3 to 4 kg. is placed on the bandage for around 6 hours. This sand bag is removed later and the first bandage is replaced with a smaller one. It is ensured that the patient drinks 1.5 to 2 liters of water in 4 hours after catheterization. Femoral area, volume of urine, and electrocardiogram (ECG) are periodically checked. The patient must keep the relevant arm or leg still as much as possible during this period. Total monitoring time for the patient is 6 to 8 hours. ECG is taken and the patient is asked to stand up and walk after doctor control. If the patient has no problems during this procedure, they will be discharged. However, if any findings of severe coronary or heart disease, or findings preventing patient from discharging are detected during catheterization-angiography, the patient and family will be informed to change the procedure.
There may rarely be problems with the placement area of heart, groin, or arm during or after cardiac catheterization.
It is a low possibility that you have pain, mild swelling and bruising (hematoma, ecchymosis, pseudoaneurism) for a few days after catheterization and angiography procedures. Occurrence frequency of this is approx 0,22% to 2,0% with experienced catheter laboratories. At our clinic, the rate of complications is around 1,2 after angiography, balloon angioplasty and stent procedures. Allergic reactions (urticaria, angioneurotic edema, anaphylaxis) and renal dysfunction to contrast material injected for imaging during procedure might rarely occur. Thus, it is important to report, in advance, predisposition to allergic reactions in particular and known renal diseases for taking necessary measures.
Enlargement of Narrowed Coronary Arteries by Balloon Catheter and Stent
It is a procedure to enlarge narrowed coronary arteries at a catheter laboratory using a balloon and/or stent placed in the vessel, or rarely by other invasive methods.
In The World and In Our Country
Enlargement of stenosis by balloon started implementing in 1977 in the world; however modern implementation was after 80s. Over 4 millions of patients around the world had a balloon and stent procedure in 2005. This is known to increase each year. In our country, around 150.000 patients had coronary angiography and cardiac catheterization in 2003 while 35.000 patients had balloon and stent procedure. At our hospital, around more than 5000 patients receive coronary angiography, more than 1000 patients receive balloon angioplasty-stent, and 2500 patients undergo a bypass operation each year.
In balloon angioplasty-stent procedure, a thin but pressure-resistant balloon catheter is placed and inflated in the narrowed section of coronary artery. The plague narrowing the vessel formed by fat, lime and various materials is partly crushed and opened.
The vital risk is lower than 0,5% during a balloon procedure. The need for an urgent bypass operation is less than 1%. This is rare but to be prepared for such possibility, two persons should be available who have the same blood type as the patient and have been previously tested. Our heart surgery department is fully prepared for a need for an emergency operation during a balloon procedure.
Metal meshes called stent have been used since 1994 to improve the success of balloon angioplasty procedure and to reduce the possibility of re-narrowing of vessels. Stents are currently used in almost all balloon angioplasty procedures. The success rate of our clinic in balloon angioplasty-stent as well as other techniques is around 98%. The rate of patients is 1% who required a bypass operation because of a failed balloon angioplasty-stent procedure while vital risk is only 0,2%
The possibility of re-narrowing of the same area is 20% to 30% within the first 6 months following a stent and balloon procedure. “Drug-eluting stents”, sterted to use in 2001, are known to reduce the possibility of re-narrowing by 5-10%. Drug-covered stents are increasingly used in our country too and considered an important development in the treatment. Drug-covered stents that are currently used in clinical practice contain sirolimus, paclitaxel, zotarolimus, everolimus and other new drugs within the thin polymer layer on the metal stent, and affect by release of such drugs.
Drug-eluting stents are significantly more advantageous than conventional stents because they reduce the re-narrowing, obstruction and the need for an intervention on the associated vessel. However, they somewhat differ among them for the abovementioned matters. The polymer layer on some new generation drug-eluting stents is able to melt away completely.
Melt-away stents “Abbott – Vascular Scaffold”
A melt-away stent, which has been largely in use for a year, is based on polymer structure. It is completely melted away within around one and a half year. The possibility of re-narrowing is same as the new generation drug-eluting stents. The rate of re-narrowing in three years is reported to be 10%.
Additional Methods Used in Diagnosis and Treatment
Sometimes, additional methods, e.g. Intravenous Ultrasonography (IVUS) and Pressure Wire, might be required to determine whether a moderate stenosis of coronary vessels requires an invasive intervention. IVUS is coronary intravascular ultrasonography and allows a more substantial evaluation of characteristics of the plague and severity of stenosis.
Pressure wire calculates the pressure rate on the front and back part of the stenosis to determine whether stenosis in the vessel severely impairs coronary blood flow. We apply both of these methods and controversial patients for who whether a coronary intervention is required can be easily differentiated.
If the plague causing stenosis is highly rough and has clots or if the veins (undergone a bypass operation) extracted from the leg have become narrowed or obstructed, a balloon angioplasty and stent procedure can be performed with a protective device. So, even very small clots and particles (emboli), which might be produced during the procedure, are prevented from travelling to the ends of vessel.
If the stenosis area in the vessel is tortuous, long, and rough and has a non-uniform wall, there are other methods, other than balloon, to enlarge the stenosis. These methods include “rotablators”, which rotate at a high revolution (160-180.000 revolution per second) and opens the stenosis with a drill capped with an abrasive diamond-studded burr; “atherectomy” which cuts and clears the rough structures of stenosis; “laser catheter” which melts and enlarges the stenosis; and “radiation” therapy.
Devices for Closing the Vessels
Recently, devices for closing the vascular access have been developed and applied successfully for patients to recover earlier. These devices are used to close vascular access by means of sutures, collagen tampons, or clips. So, there is no need for exerting compression or placing a sand bag after the procedure and the recovery time is reduced.
The first few days after the procedure
The cannula in the groin is removed in 4-5 hours after successful completion of invasive methods, e.g. balloon and stent. The bandage and the sand bag placed on are kept for 6 hours. Then the patient is assisted to stand up and walk. The patient is usually discharged in 2 days.
An appointment is made with “Balloon-Stent Polyclinic” for checks on the months 1, 3, and 6 after the procedure. The patients, who are considered necessary, have an effort test, and a blood test to assess blood lipids and revise medication during these checks.
Balloon and stent interventions in cardiac veins and non-cardiac veins
Balloon and stents procedure is safely performed for stenosis of vessels in legs, arms, kidneys, carotid, and brain other than cardiac vessels.
During a heart attack (Acute Myocardial Infarction);
EMERGENCY (PRIMARY) CORONARY BALLOON AND STENT PROCEDURE
A heart attack (Acute Myocardial Infarction) occurs when a coronary vessel supplying heart’s muscular tissue is instantly clogged. Heart muscular tissue becomes damaged by clogged coronary vessel. In order to minimize this damage, anticoagulant drugs (thrombolytic) are immediately administrated, or balloon and stent procedure is performed. If patients who are having a myocardial infarction present within the first 6-12 hours, clogged coronary arteries or coronary arteries about to clog are possible to enlarge by balloon angioplasty and stent procedure.
This procedure provides successful results in patients who are having a “myocardial infarction” and who are considered suitable after a cardiologic assessment. If the patients apply to a hospital as soon as they feel coronary complaints, they will have optimum outcomes. Applications during the first 6 hours in particular are critical.
“The earlier the intervention is performed, the greater gain a patient achieves.”