Kathryn E. Glas, MD, FASE

Scott T. Reeves, MD, FASE

The Intraoperative Council (IOC) produced guideline documents related to both epicardial echocardiography and epiaortic ultrasonography in the past 2 years. The epicardial imaging planes were developed to correlate with existing transthoracic imaging planes to maximize global ability to interpret the findings. Epiaortic imaging planes are based on those already in use in the cardiac surgical arena. Many practicing perioperative physicians do not have experience with epicardial imaging due to the widespread availability of TEE and the low incidence of need for alternative imaging modalities. These same physicians also do not have experience with TTE imaging, though that is changing as more individuals understand the value of TTE and are attending courses to learn the technique. Uniquely, anesthesiologists learn TEE preferentially in our training due to the widespread use in cardiac surgical operating rooms. It has been uncommon for individuals in our field to learn transthoracic echocardiography (TTE) simultaneously.

Two distinct skill sets are needed to master this ‘new’ technique of epicardial imaging: understanding of TTE images, and surface probe placement/manipulation. The guidelines recommend performance of 25 examinations, in addition to advance echocardiography certification, for independent practice. We have found concomitant use of TEE and epicardial imaging to be a useful initial training tool for this practice. By viewing TEE images and epicardial images simultaneously, trainees can directly compare the data and reinforce epicardial learning with baseline TEE skills. Having a heart model nearby is also helpful in learning anatomic correlations for surface exams.

The epicardial guidelines provide detailed description of probe manipulations to assist with performance of the exam. Although the surgical retractor impedes left ventricular views on occasion, a new surgical trainee, with assistance, can complete a complete exam in less than 10 minutes. Image quality is better than TTE since a high resolution probe can be used. One issue we have had with these images is the difficulty in aligning the transducer correctly, since the probe marker isn’t visible through the sterile sheath. When you see images that are backwards, it is because we are short on time, not short on knowledge of proper image orientation.

Epiaortic imaging has been in use at many institutions for almost as long as TEE and epicardial imaging, and can easily be accomplished with preexisting equipment (TEE machine and a high resolution probe). Epiaortic ultrasound guidelines are similar to epicardial ones in that advanced echocardiography certification is required in addition to 25 personally performed examinations. The procedure itself takes less than 5 minutes and requires a limited number of images. Overwhelming evidence in the anesthesiology and cardiac surgery literature support the enhanced visualization of atheromatous burden in the aortic root, ascending aorta and proximal aortic arch, identified by epiaortic imaging over TEE acquired views. Despite this improved atheromatous burden identification, there is as yet no data to confirm that management changes impact outcome. A prospective, randomized trial is not an option due to wide variations in practice and ethical objections to standardized management schemes that include blinding surgeons to results or manipulating through disease felt to be high risk for embolism. A common catch-22 exists with epiaortic imaging. There isn’t enough data to support a common grading scale that could lead to multicenter trials of outcomes. There aren’t enough financial or personnel resources to decipher current multicenter data to determine if further study is even warranted. But those of us who are believers think it may prevent weeks of intensive care time by identifying and avoiding atheroma that would otherwise embolize to the brain. Our sole regret with this technology is that federal regulators do not recognize its importance enough to provide financial remuneration to those of us who utilize resources in an attempt to minimize untoward patient outcomes. Maybe pay for performance metrics will encourage more use of this valuable technique.

At the 2010 ASE annual meeting in San Diego, the Intraoperative Council will be hosting an all-day valve session on Saturday, June 12 that should not be missed. The summit will include a porcine heart dissection by a prominent surgeon and cardiac anesthesiologist. Common and rare valve pathology will be presented in a case-based format by an intraoperative team of surgeons, CT anesthesiologists, cardiologists and sonographers. Cases will have surgical footage as well as preoperative and intraoperative imaging studies. This will be an exciting session; please make plans now to attend. As the leaders of the IOC, we all look forward to seeing you in San Diego.