Medtronic first-generation Revo MRI SureScan Pacing System has some significant limitations.
1. The MRI-pacemaker is for new heart patients. Patients who already have a pacemaker can not get this new model unless they undergo the risky procedure of having their old pacemaker completely removed. Usually, when it comes time to replace the battery in a pacemaker (about 5-7 years), the metal case containing battery and circuitry is detached from the leads, and a new model device is hooked up to the leads. But doctors generally consider it too risky to remove the old leads from the heart for fear of tearing the heart or the veins through which the leads are inserted into the heart. Part of the design of the Revo pacemaker is its new leads and so they must be the leads that connect the pacemaker to the patient’s heart.
2. Patients must have the Revo pacemaker implanted for 6 weeks before receiving an MRI.
3. The Revo pacemaker requires a certain position of the patient inside the MRI tube so as to avoid most chest scans. This is to prevent overheating the metal tips of the leads that are attached to the heart. So heart scans are forbidden with this first generation model.
4. And Owen Faris, senior scientific reviewer for the FDA, explains that the new pacemaker won’t work for all types of MRI scans and won’t work in all MRI scanners. In his words:
In addition to the chest scan exclusion, there is a restriction on how much radio-frequency energy can be deposited into the body by the scanner. MRI scanners have two operating modes for most clinical applications. ‘Normal operating mode’ is how the scanner is normally programmed and that mode restricts the scanner to lower-energy scans (less than 2 Watts per kilogram). This is sufficient energy for most clinical MRI scans. However, for some patients and for certain scans, more power is needed. In those cases, the MRI scanner is placed in ‘First level control’ mode, which allows for greater energy deposition (up to 4 Watts per kilogram). For patients implanted with the REVO MRI pacemaker, those patients are not allowed to have these higher energy scans.
MRIs for these patients are also restricted to only allow use of 1.5 tesla MRI systems. "Tesla" is a measure of the strength of the magnetic field.
5. Medicare does not now pay for MRI scans on a patient who has a pacemaker. Medtronic spokesperson Wendy Dougherty says that the company will not speculate on whether Medicare will cover MRIs done on patients wearing the new Revo pacemaker. The federal agency is considering a petition from a physician to cover MRIs done during an investigational study to determine the risk of MRIs involving pacemakers already in use. During the comment period for this request, Medtronic asked Medicare to restrict MRI payment to patients wearing pacemakers approved by the FDA for use with MRIs. Medicare’s decision is due by March 1. Patients on Medicare would be wise to check on whether their plan will pay for an MRI before getting the test, which costs between $1,600 and $3,500 at different medical centers and offices.
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