Alternatives to today’s drug-eluting stents

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By David Smith

Drug-eluting stents are a very effective therapy for minimising the problems of basic ischaemic complications within the coronary artery in the short to medium term. If an artery has been blocked, these stents are good for keeping it open and free of problems. The trouble, however, comes when we have to balance that benefit against the safety precautions in specific groups of patients. For these individuals, it is important that we find alternative options for stenting.

 

In most of the challenging cases, the safety concerns with drug-eluting stents are related to the need for patients to take blood thinning agents, usually dual-antiplatelet therapy, for one year after the stents have been implanted.

Unfortunately, our focus for too long was on preventing ischaemic complications by using more potent blood thinning drugs, whether it was an antiplatelet agent or antithrombotic drugs. There is a price to pay, and that price is bleeding. If patients bleed post-angioplasty procedure, it is not good, and their outcomes are compromised. In the last few years, this focus has changed as we realised this fact.

 

There are many patients who may be unable to tolerate a year’s worth of two different blood thinning agents for a variety of reasons. For example, we are presented with challenging cases by those patients who may need to undergo surgery for non-cardiac reasons within the next year. We can effectively treat their coronary artery, but in the process condemn them to the prolonged blood thinning treatment that may have a hazardous effect on their planned surgery. In some cases, the blood thinners may even preclude them from having their planned surgery.

 

Diabetic patients present particularly challenging cases for other reasons. Not only are they more prone to coronary disease, they also have comorbid health problems that place them at a higher risk than non-diabetics of developing complications with their stents.

 

These risks are particularly alarming as we look at the growing percentage of people diagnosed with type 2 diabetes. Recent studies have shown that it is a pandemic in the USA, and we are seeing the same in Europe. We also know that not only is this a real problem at the current time, it is a problem that is going to grow with time.

 

Early on, diabetics were seen to have a higher rate of renarrowing of the coronary arteries when bare metal stents were used. For this reason, drug-eluting stents were used heavily to try and improve outcomes. However, these did not improve safety by much, and the patients have shown problems with tolerance of the medications.

 

Hyperglycemia and any form of formal diabetes also cause problems because low blood sugar impairs the healing process. As a result, we are being forced to move away from a purely mechanical approach to stenting and realise the importance of the vessel healing following intervention. We have to think of both the mechanical and bio-mechanical approach to coronary intervention by optimising and improving the healing of the vessel.

 

Technology that uses advanced methods of healing is demonstrating great results in treating these patients without raising the same safety concerns. For example, technology that can capture endothelial progenitor cells, or EPCs, offers promise to treating these challenging cases. In my practice, I have used this type of technology for approximately three and a half years with tremendous results in these challenging cases.

 

This approach relies on speeding re-endothelisation to improve the healing process. In doing so, the need for dual-antiplatelet therapy and risks associated with the healing process are minimised. It is not only very attractive theoretically, but we have seen results from studies that seem to hold the premise true. This rapid re-endothelisation of the stented portion of the coronary artery is translating into improved short-, medium- and long-term results.

 

The ability to reduce the duration of dual-antiplatelet therapy is very important. In many cases, this course of therapy is reduced from one year to one month. Having an option for the duration of the treatment is a major win for patients and physicians. This reduces the risks for patients who may need additional surgeries or have problems with bleeding. As a result, the outcomes for these patients improve.

 

In my practice, I have had very few patients implanted with this technology return due to a failure of the artery to remain open or an inability to tolerate the shortened course of dual-antiplatelet therapy. The ability to select an appropriate technology based on the patient’s needs truly presents us with a win-win situation.

David­­­­ Smith is a consultant cardiologist at Morriston Hospital, Swansea, UK.