What is a drug-eluting balloon?
In recent years, balloon models coated with special medication like stents have been developed. These are briefly called “drug-coated balloon” (DCB: Drug-Coated Balloon). When the balloon is inflated, the drugs on its surface penetrate the vessel wall and thus prevent excessive amount of tissue growth which plays an important role in re-occlusion of the vessel. Drug-coated balloons, unlike drug-eluting stents (DES: Drug-Eluting Stent) do not leave a metal structure inside the vessel. Thanks to this, the vessel, does not lose its elasticity; that is, it can continue its function of being able to contract and expand when needed. Additionally, they allow for a shorter duration of use of additional blood-thinning medication. However, even if drug-coated balloon application was planned, immediately after balloon angioplasty as a result in average 1 out of 4 cases the vessel’s re-closure after being opened (collapse/recoil) or unexpected excessive cracks in the vessel (dissection) may occur, therefore a scaffold (stent) must be placed after balloon angioplasty, it must be emphasized.
Which is better: a drug-eluting balloon or a drug-eluting stent?
When we do not have sufficient data, the most healthy and scientific approach to be applied is to continue with treatments whose results are known and established. Because science works with evidence. For example, biodegradable stents were very popular a few years ago. Although there were no comparative scientific studies conducted with non-biodegradable (metallic) drug-eluting stents, the fact that these stents could dissolve and leave no material behind seemed theoretically very appealing to the mind. In fact, it even seemed more logical than drug-coated balloons. For this reason, most patients and doctors thought that using biodegradable stents was more correct compared to non-biodegradable stents. But when the results of quality comparative scientific studies were published, it was seen that this was not the case at all. It was understood that biodegradable stents did not fit properly to the vessel wall in some patients, fractures occurred in the stent structure, and some parts did not dissolve completely. Because of these problems, it was understood that patients with biodegradable stents had a higher risk of sudden vessel occlusion-related heart attack and death compared to patients with drug-eluting stents. As a result, biodegradable stents were withdrawn from use. Let us keep this information in a corner of our mind and see what the currently available scientific data says about drug-coated balloons, which have been increasingly used in recent years:
- Drug-coated balloons are better than drug-free balloons.
- Drug-coated balloons are equally effective as drug-eluting stents in thin vessels. In narrow-diameter (≤2.75 mm) vessels, there is not enough space for tissue growth that would cover the stent, so occlusion develops more frequently compared to larger vessels. However, even in these thin vessels, drug-coated balloons are not better than drug-eluting stents, but they are not worse either; that is, they are equally effective. Thin vessels are the group in which drug-coated balloons should be most appropriately used; in these situations, I (Prof. Dr. Şükrü Akyüz) use them frequently.
- If a possible bypass surgery is needed in the future, drug-coated balloons are preferred over drug-eluting stents for narrowings located at the anastomosis site where the graft vessel will be attached. Because the stent may prevent the graft from being attached to the vessel.
- In cases where a certain portion of the vessel courses within muscle tissue rather than on the surface of the heart (intramyocardial course), using a drug-coated balloon is theoretically more logical than using a stent. Because if a stent is placed, every time the heart contracts it may squeeze the stent, eventually causing the stent to fracture and subsequently occlude.
- If a previously placed stent narrows over time due to excessive tissue growth (ISR: In-stent restenosis), placing another drug-eluting stent in this area (stent within stent) is generally better than applying a drug-coated balloon. We say “generally” because some studies presented at scientific conferences have reported that some drug-coated balloons are as effective as drug-eluting stents in both large vessels and in-stent occlusions (For details, we have to wait for these studies making such claims to be published and interpreted in quality scientific journals). In recurrent in-stent occlusions (recurrent ISR), drug-coated balloon application is preferred; because it is theoretically thought that a third stent layer would further occlude the vessel.
- For other vessel types [main vessels 3 mm and wider in diameter (including LMCA), bifurcating vessels requiring two stents, completely occluded vessels (CTO)…] quality (large, randomized and controlled) scientific studies comparing drug-coated balloons with drug-eluting stents do not yet exist. For this reason, their routine use is not recommended in these situations. The results of future scientific studies will determine their ultimate effectiveness and safety. Perhaps even in these situations, drug-coated balloons will truly yield results as good as or even better than drug-eluting stents and will enter routine use. Or perhaps in most situations they will be seen to not provide better results than drug-eluting stents and will continue to remain in limited use (See References).
Can a drug-coated balloon save the patient from a stent or bypass?
Current scientific guidelines recommend bypass surgery or complex stenting for LMCA or 3-vessel occlusions. Drug-coated balloons also generally open these vessels; but the issue is not just “opening the vessel.” Yes, when the vessel is partially opened with a balloon (for example, when 90% narrowing regresses to 50%), blood flow will increase and the patient’s symptoms will initially resolve. But the question “Will the vessel remain open in the long term?” is much more important. However, unfortunately, in some social media accounts and websites, albeit rarely, it is claimed that vessels are opened with the help of drug-coated balloons without even placing a stent, that is, without leaving metal behind, and thus patients are saved from complex stenting procedures or bypass surgery. This is contrary to scientific guideline recommendations and is medically incorrect; because it potentially carries the risk of error. That is, are we sure that the outcome of applying drug-coated balloons in these cases will not result in long-term disappointment like the outcome of biodegradable stents experienced in the past? If it should happen that comparative quality scientific studies to be conducted in the future prove that drug-coated balloons are as good as drug-eluting stents in complex cases, of course, most interventional cardiologists, including myself, will prefer drug-coated balloons over drug-eluting stents. Because applying a drug-coated balloon is many times easier than complex stenting procedures. Ultimately, balloon application is fundamentally a balloon inflation action; it is not as dependent on the doctor’s knowledge, experience, manual skill, and special material requirements as stent procedures are.
For serious decisions such as treatment selection, we recommend that you get a second opinion from a different physician. It is important that you request the most current scientific evidence for the recommended treatment to be presented in understandable language, along with references.