Transthoracic echocardiography can play a vital role in device implantation procedures, from preparation to follow-up.
Professor of Anaesthesiology at the Duke University Health System, Madhav Swaminathan, explained that the imaging modality had the ability to avert complications at every stage.
Devices
He started his talk with an overview of the role of mechanical circulatory devices (MCS) in advanced heart failure (HF).
People might be treated with a long-term MCS as a bridge to orthotopic heart transplantation (OHT) or if they are illegible for OHT. Those in acute shock or whose OHT status is unknown will usually have a short-term MCS, Prof Swaminathan explained.
The appropriate choice of device will depend on its purpose, he added (see table 1).
| Purpose |
Duration |
Devices |
| LV failure |
Temporary |
IAMP, Impella, Centrimag |
| Durable |
HM3, Heartware, Thoratec |
| RV failure |
Temporary |
Protek Duo, Centrimag, Rotaflow |
| BiV failure |
Temporary |
VA ECMO, Thoratec, Bilateral Centrimag, Bilateral Rotaflow |
| Durable |
Bilateral HM3, HM3+Heartware |
|
| Table 1: Implantable devices by purpose |
Imaging goals
Explaining what to look for on imaging, Prof Swaminathan highlighted the importance of excluding relative contraindications to implantation ahead of the procedure. These include aortic regurgitation, patent foramen ovale (PFO), and mitral stenosis, which may need to be addressed prior to implantation.
Echo can also be used to ensure cannulae positions are correct, both during and after the implant. Look at the right atrium (RA), right ventricle (RV), and pulmonary artery (PA) for right sided procedures, and at left ventricle (LV) and the ascending aorta for left sided interventions, Prof Swaminathan told the conference.
Utilising imaging to guide positioning either during or after implantation is especially important with extracorporeal membrane oxygenation (ECMO) and left ventricular assist devices (LVAD). If the inflow cannula is tilted to the left, it can suck the septum in and significantly impact RV function, for example.
“Then you want to look for other complications, such as air, especially when the patient is coming off cardiopulmonary bypass (CPB),” said Prof Swaminathan, adding that potentially dangerous air bubbles are very easy to see on imaging.
Assessing complications is another important imaging goal in this setting. RV failure, hypovolemia, worsening aortic regulation (AR) and worsening mitral regurgitation (MR) can all occur while a patient is coming off CPB and immediately afterwards.
Post-op
Tamponade and thrombus are very important in the post-operative period on the ICU, said Prof Swaminathan.
“Sometimes the thrombus issue is more common in ECMO devices, where you have more stagnant flow either in the LV or through the pulmonary circuits,” he said, adding that this can be very dangerous.
Echo’s role
Summarising, Prof Swaminathan said transesophageal echo can be used to confirm cannula positions and device function and to guide cannula repositioning and de-airing. “Be sure to look out for RV failure, tamponade, worsening regurgitation, device failure, and thrombus formation,” he said.
BSEcho 2020 presentations are available on our website for members of the Society.
View the presentations