Dual Coil leads are still on the top line but single coil ones are rapidly approaching.
Posted: January 6, 2014 Filed under: eHealthCare, Medical Devices Leave a commentWith NayaMed you are a winner in both cases.
The new NayaMed single coil leads with DF-4 connector
One of the objectives of NayaMed is to offer to physicians a streamlined offer of devices and leads, bringing to market the products covering all the needs of the big majority of patients. In this respect the initial focus was on the high voltage leads with DF-1 connection and on the dual coil leads with DF-4 connector.
There is no doubt in the last 20 years dual coil leads have been preferred and until recently in most part of the world the usage of single coil leads were not more than 25% [1]. Probably the 1st reason in choosing by default the dual coil system is the results of some studies performed in the nineties, where it appears a lower DFT was demonstrated in ICD systems with 2 coils [2][3][4].
Except those early trials, there are recently more and more evidence showing that no difference was found between single coil vs. dual coil for the 1st shock arrhythmia termination for VT / VF and there is clinically equivalency in the 1st shock efficacy [5] especially if we think about the new devices on the market with 35 Joules delivered energy.
In 2003 already, Rinaldi and all. concluded there is no significant difference in DFTs between single coil and dual coil leads in the same population. The article is also enquiring about the disadvantages a dual coil lead could eventually have; promoting more fibrosis, leading to more risky and difficult extractions [6].
So we can ask why implanters worldwide are still using mostly dual coil leads despite this recent evidence. First of all, I think changing habits is not easy, than when you have good experience and no problems with an ICD lead you are used to stick to it. Then when you implant a dual coil lead you always have more options in case of a higher DFT and this is actually true as a dual coil lead gives you the option of 3 shocking vectors (RV to SVC + CAN, RV to CAN, SVC to CAN) while a single coil gives you only one option (RV to CAN). Who can do more, can do less also…
Also, there is generally no (or no more) diameter size difference between the single coil and the dual coil leads from the same family and probably most of all, when you are implanting a lead you don’t really think at its extraction.
In the last 10 years, the number of ICD implants significantly increased [7] passing in Europe from 38 implants per million in 2000 to 252 implants per million in 2010, thus more and more people being actually saved from dying due to Sudden Cardiac Death (SCD).
This big increase in the number of implants brought an increase in the number of technical issues related to the ICD system, more precisely issues with the high voltage leads, those one being considered the “weakest link” of the ICD system [8]. Who says lead problems says lead extractions and this is the moment when potential disadvantages of a dual coil lead start to be more visible bringing the fibrosis and the increase risk extraction on the table. The centers performing lead extractions started to implant more and more single coil leads.
This year, Aoukar and all. published an article called “No benefit of a dual coil over a single coil ICD lead: Evidence from the Sudden Cardiac Death in Heart Failure Trial” and to our knowledge it is the only article where other aspects than the arrhythmia termination were analysed. The base of the article is the SCD-heft trial and in this specific analyse the authors compared different clinical aspects between the populations with single vs. dual coil ICD leads implants. The results are the following: no statistical difference in SCD risk, in the rate of inappropriate shocks, in the 1st shock efficacy, in DFT test energies and above all no statistical difference in mortality between patients implanted with a single coil versus a dual coil lead [9].
Following those evidences that are completing the ones founded since 10 years it is normal and expected that the number of implants with single coil leads to increase. In 2012, in Sweden 59.4% of all the ICD leads were single coil.
This is why, in the ease of their offer NayaMed decided to freshly add a DF-4 Single coil lead to their portfolio; ND X4 01. It is an active fixation lead with silicone insulation and polyurethane overlay.
Earlier I was mentioning the ICD lead is probably the weakest link on the ICD system. Well with this in mind we decided to have a stronger link. Similar to its “older sister”, ND X4 02 (dual coil lead with DF-4 connector), the ND X4 01 is based on a lead model with more than 10 years of proven performance.
They are both meant to be implanted with any standard ICD with DF-4 header on the market, specifically with our dual or single chamber defibrillators, ND X4 DR and ND X4 VR.
Dr. Paolo Diotallevi
Eng. Alexandru Trif
NayaMed 