Dr. George Papaioannou, MD MPHDirector of the Hemodynamic Lab of the Athens Medical Center.
The coronary artery disease is a heart arteries disease and is the main reason of morbidity and mortality to men and women of the western hemisphere. This means that blood vessels (coronary arteries), which provide blood and oxygen to the heart, develop some type of stenosis or blockage, leading either to angina or myocardial infarction (necrosis), even to sudden death. The final diagnostic exam for the verification or not of the diagnosis is coronary angiography, while in many cases, treating the disease includes further invasive techniques (angioplasty – stent placement), if deemed necessary.
Coronary angiography method
Invasive cardiology uses the human circulatory system (arteries) as a «route» for the passing of small catheters (little tubes, shaped like macaroni) of 2 mm diameter or even smaller, which are lead painless to the area of the heart. Those little tubes allow the administration of radiopaque liquid inside the coronary arteries, by which the artery network of the heart is depicted. The insertion of the catheter to the artery is usually done via leg puncture (femoral artery). The puncture could also be done to the arm βραχίονα (humeral artery) or to the wrist (radial arteryαρτηρία). The last one is the ideal approach for the minimally invasive coronary angiography.
Leg puncture is the most frequently used technique for the creation of a route to the circulatory system and the insertion of catheters up to the heart in order to display coronary arteries. This technique, invented back in 1960, is the most widely used, but has some limitations. The femoral artery could have some disease (e.g. a patient with peripheral artery disease), something that does not allow a catheter’s insertion. In other cases, the patient is overweight and the femoral artery is located deeply inside subcutaneous tissue, making the approach quite difficult and also its compression after the end of the surgery even more difficult in order to stop hemorrhaging. Rarely, a potential hemorrhage by the artery after the end of the exam is not visible to the naked eye and could happen to the back of the artery, creating from a simple discoloration to a crucial hematoma. Finally, with the femoral artery puncture there is a small possibility of damaging the femoral nerve, due to the fact that it is located to close proximity. All previous complications, despite the fact of their low number, are the limitations of the femoral approach for coronary angiography.
Most limitations related to the approach by the femoral artery do not exist to the radial approach.
Despite the fact that the radial artery is much smaller in diameter in comparison with the femoral artery, each diameter is sufficient to allow most catheters to pass through it and to reach the coronary arteries. Further improvements of the materials have lead to the creation of special sheaths (the small tubes initially placed initially inside the artery), which are autramatic, as well as special catheters of a smaller diameter for the conduction of the diagnostic coronary angiography as well as of the surgery to the coronary vessels (angioplasty and/or stent placement).
Advantages of the radial approach
Most limitations related to the approach by the femoral artery do not exist to the radial approach. Even for overweight patients, radial approach is close to the skin, making the initial puncture much simpler. For the same reason, when diagnostic coronary angiography has finished, a short compression of the radial artery is sufficient to stop bleeding, even in patients receiving anti-clotting medication, such as after the execution of angioplasty. Finally, the radial artery is not proximal to any large nerve. Thus the possibility of damaging a nerve during surgery is not existent.
Radial approach does not present the risk of bleeding. Thus, the patients do not need the painful pressing of the femoral artery after the end of the exam or to lie down for many hours in order to avoid potential hemorrhage from the femoral artery. After the end to the diagnostic exam they can get up and walk right away. Also, due to the simpler process of healing of the artery wound on the wrist, most patients are able to leave to leave the hospital in a few hours without the need to spend the night.
Are all patients eligible for radial approach?
There are some requirements for a patient to be perfect candidate for the minimally invasive coronary angiography. The first one is to certify that there is a «double» supply of blood in the hand. The radial artery creates a loop in the hand and is united with the ulnar artery. Both arteries supply blood to the hand and fingers (Image 3). This double blood supply of the hand makes the radial approach completely safe. Even if the radial artery for some reason is “blocked” (a very rare complication), the clinical result is not important due to the fact that the hand is still supplied by the ulnar artery. The first step of the invasive cardiologist is to test the normal operation of both radial and ulnar artery. A simple test, which is done by pressing the arteries of the hand, is able to show the double provision of blood to the hand. If the test fails then the femoral approach is the preferred choice. Also, the femoral artery is preferred, when we know in advance the need to use catheters of larger diameter, the presence of bypass grafts and/or the coiling of blood vessels in the neck, which could inhibit the passage of the catheter from the hand to the coronary arteries. In total a high percentage of patients (70%-80%) are eligible for radial approach.
The first step of the invasive cardiologist is to test the normal operation of both radial and ulnar artery.
What are the reasons for the limited use of the radial approach in Greece?
The most common reason that patients are not informed for the radial approach is that that there is a very small number of invasive cardiologists that prefer this technique. Many places in Europe and/or Japan and also the United States of America and Canada have centers that are using either exclusively or mostly the radial approach as the main approach for the conduction of diagnostic coronary angiographies and angioplasties. Other reasons for the low use of radial approach for the conduction of coronary angiography is the lack of financial motive from the part of insurance companies and also hospitals but mainly due to the existing structure of the insurance system, the lack of information by patients and also the reluctance of invasive cardiologists to promote this technique. However this situation changes dynamically. More and more centers and invasive cardiologists begin to see the advantages of radial approach characterized by low implications, increased satisfaction on behalf of the patients, but also lower cost (reduced hospitalization time and low percentage of complications). At the Medical Center of Athens, the radial approach is for the last two the main personal diagnostic approach of patients submitted to coronary exams.
The femoral approach for the conduction of coronary angiography exists and will exist as a main technique for many years. The radial approach, offering a minimally invasive coronary angiography with almost zero percentage of complications and excellent satisfaction on behalf of the patients, requires specialized medical and nurse staff and greater skills. But its advantages are such that will make it the main approach for diagnostic and treatment purposes to the coronary vessels for the next years.
By Georgios Ι. Papaioannou, MD, MPH, FACC, FSCAI Invasive Cardiologist, of the Hemodynamic Lab of the Athens Medical Center.