Letter from the Editor

Hot topics for 2006: Where to focus your attention

Morton Kern, MD, Clinical Editor
Morton Kern, MD, Clinical Editor
The methodologies for this fast-growing group of procedures have been well described. For both ASD and PFO, the equipment is generally operator-friendly and the technique for placement relatively straightforward for those performing coronary interventions. However, unlike routine cath lab procedures, in most cases the cath physicians and staff must coordinate with other physicians and associates involved in general anesthesia and the transesophageal echocardiography (TEE) used in guidance of the procedure. In some centers, intracardiac echo has replaced general anesthesia and TEE, but it requires more experienced operators and interpreters for the imaging of device placement. On a personal note, I have found that it is difficult to manipulate the PFO sheath and also position the imaging catheter to see where the device needs to go. An extra pair of experienced hands is not always available. Intracardiac (IC) echo is probably suitable for PFO placement, but its use may make it more difficult to assess a satisfactory ASD placement. The difficulty lies in the need to identify and confirm the surrounding tissue dimensions of the secundum ASD, such as size of the inferior rims of primum septum and distance from the right superior pulmonary vein, as well as any secondary small ASDs.
What does this mean for the cath lab? The PFO/ASD procedure itself is not complex, but staff will need to become familiar with the anatomy of the heart, specifically, the interatrial septum, its defects and nearby structures, a task both challenging and stimulating. Bringing echo into the cath lab is rare for routine procedures, but should be viewed as an opportunity to broaden everyone’s knowledge base in order to help with the patient’s care and their understanding of what is happening. It would behoove all involved to have one of the physicians knowledgeable in the procedure review the landmarks and pitfalls with the staff beforehand, so all can become engaged in the technique.
The bigger issue with regard to PFO closure is the indication in patients with a transient ischemic attack (TIA)/cerebrovascular accident (CVA) or refractory migraine headaches. Currently, no conclusive study exists to demonstrate that the PFO closure is superior to medical therapy (consisting of ASA and coumadin). The Humanitarian Device Exemption (HDE) indication for placement of an Amplatzer PFO-occluding device (AGA Medical Corp., Golden Valley, MN) is a recurrent neurological event (presumed to be microembolic event without other source of stroke/TIA), which is refractory to medical therapy. Although this sounds reasonable, imagine how difficult it is to say to the patient, We’ll have to wait until your second stroke on therapy before we close your PFO, the only identified possible source of the event. Physicians are dealing with this situation in a variety of ways, reviewing in more detail the clinical presentations and multiple imaging studies.
As for PFOs and refractory migraine headaches, no randomized data regarding closure for this reason exist. A large-scale, multi-center trial is underway. If this study is shown to be positive, the number of PFO closures could increase dramatically, providing improved therapy to the thousands of migraine suffers. We should wait for this data before implanting PFO devices without demonstrated benefit.
What should the cath lab be thinking about? As with all implantable devices, the consequences of a breach in sterility are serious. As compared to routine stent implantation, I would recommend a heightened level of vigilance regarding sterility, including masks and hats for all personnel, using only a single-use immersion bath for the device and a change of gloves (if not gowns for the operators) before device implantation. Some centers are routinely using antibiotics following implantation. As for the patient in the post-procedure period, the device is a potential source of infection until it is fully endothelialized, which takes a minimum of 6 months.

Plavix for 6 months and ASA for life are currently recommended. On the cautious side, antibiotic prophylaxis is a good idea for at least the first year, if not longer, since we cannot know when the device is completely covered.
Over the next few months, I hope to expand on other issues of interest, such as contrast-induced nephrotoxicity, role of peripheral vascular and carotid interventions in the cath lab, the best sources of information for staff and patients, and new approaches to cath lab education as the digital era takes over the lab. Contact CLD with your needs. I look forward to your feedback.