Coronary Artery Radial Deformation and Velocity in Native and Stented Arteries.

Introduction: Coronary arteries are exposed to a variety of complex biomechanical forces during a normal cardiac cycle. These forces have the potential to contribute to coronary stent failure. Recent advances in stent design allow for the transmission of native pulsatile biomechanical forces in the stented vessel. However, there is a significant lack of evidence in a human model to measure vessel motion in native coronary arteries and stent conformability. Thus, we aimed to characterize and define coronary artery radial deformation and the effect of stent implantation on arterial deformation. Materials and Methods: Intravascular ultrasound (IVUS) pullback DICOM images were obtained from human coronary arteries using a coronary ultrasound catheter. Using two-dimensional speckle tracking, coronary artery radial deformation was defined as the inward and outward displacement (mm) and velocity (cm/s) of the arterial wall during the cardiac cycle. These deformation values were obtained in native and third-generation drug-eluting stented artery segments. Results: A total of 20 coronary artery segments were independently analyzed pre and poststent implantation for a total of 40 IVUS runs. Stent implantation impacted the degree of radial deformation and velocity. Mean radial deformation in native coronary arteries was 0.1230 mm ± 0.0522 mm compared to 0.0775 mm ± 0.0376 mm in stented vessels (p=0.0031). Mean radial velocity in native coronary arteries was 0.1194 cm/s ± 0.0535 cm/s compared to 0.0840 cm/s ± 0.0399 cm/s in stented vessels (p=0.0228). Conclusion: In this in vivo analysis of third-generation stents, stent implantation attenuates normal human coronary deformation during the cardiac cycle. The implications of these findings on stent failure and improved clinical outcomes require further investigation.

When an unidentified foreign object appears in the inferior vena cava: recognizing the presence of TIPS stent on transthoracic echocardiographic imaging.

We describe the case of 65-year-old female with a history of hypertension, diabetes, and cirrhosis. In the subcostal view on a routine transthoracic echocardiogram (TTE), she is found to have an unidentified round prosthetic appearing object in the inferior vena cava (IVC). Upon further investigation, the object was identified as a transjugular intrahepatic portosystemic shunt (TIPS) stent, which was seen in cross section in a hepatic vein draining into the IVC. Most echocardiographers are unfamiliar with the appearance of a TIPS on TTE. Being able to recognize this will help avoid misdiagnosis and unnecessary further imaging.

Mobile ascending aortic atheroma diagnosed by transesophageal echocardiography as source of peripheral vascular embolism.

Complex aortic atheromas are an important differential diagnosis to consider in evaluating sources of arterial embolization. Diagnosis of the embolic source is an essential first step, so treatment can then be initiated to prevent further reoccurrence. We report the case of a 36-year-old man, without significant medical history, who presented to the University of Illinois at Chicago with peripheral vascular embolism to the lower extremities. Computed tomography with contrast angiography and transthoracic echocardiography failed to reveal a source of the thromboembolism. A complex mobile atheroma was discovered in the ascending aorta during transesophageal echocardiography. The case presented is noteworthy when considering the following: the relative rarity of complex atheromas of the ascending aorta, the young age of the patient with no history of atherosclerotic disease, and the failure of computed tomography angiography to reveal the embolic source despite literature supporting high sensitivities for aortic plaque detection compared with transesophageal echocardiography.