Comparative Feasibility of Myocardial Velocity and Strain Measurements Using 2 Different Methods With Transesophageal Echocardiography During Cardiac Surgery

A comparative study between transthoracic and transesophageal echo modalities in evaluation of left ventricular deformation

BACKGROUND

2D strain imaging has been proved as an accurate technique for the assessment of left ventricular (LV) function using transthoracic echocardiography (TTE). Transesophageal echocardiography (TEE) has become a standard and essential technique in clinical practice especially when TTE is inconclusive. Adding 2D strain imaging to TEE might be valuable in the evaluation of cardiac performance. The aim of the present study was to compare 2D strain imaging using TTE and TEE in the assessment of left ventricular deformation in patients with cardiovascular diseases.

RESULTS

This study was conducted on sixty patients, who were referred for TEE for various clinical indications. All patients were examined with both TTE and TEE 2D strain imaging. Global and regional strain parameters including longitudinal (LS), circumferential (CS), and radial (RS) were examined. Analysis of 2D strain using TTE was time sparing than TEE (16 ± 1 vs 19 ± 2 min, P < 0.001). From 1020 segments explored using TTE, 97% (LS) and 93% (CS and RS) of the segments were fully analyzed versus 90% and 88% using TEE respectively (P < 0.01). TEE longitudinal strain has an excellent agreement with TTE-derived measurements and a modest agreement in circumferential strain but a notable disparity in radial strain values. Both regional and global LS and RS measured by TTE showed higher values (P < 0.01, < 0.03) compared with its corresponding values measured by TEE. Whereas segmental and global values of CS were higher using TTE modes, the difference with the analogous TEE values did not reach statistical significance. LS and CS measured by TTE and TEE showed excellent but similar correlation with LV EF and wall motion score index.

CONCLUSION

2D strain using TTE is user friendly compared to TEE. However, because of the good agreement, TEE 2D strain might represent an appropriate alternative in the evaluation of global LV deformation.

Instantaneous Decrease in Left Ventricular Afterload during Transcatheter Aortic Valve Implantation Results in Immediate Changes in Left Ventricular Strain

Severe aortic stenosis causes chronic increased afterload on the left ventricle (LV) resulting in myocardial hypertrophy and ultimately dysfunction if left untreated. Transcatheter aortic valve implantation (TAVI) immediately decreases the afterload on the LV by reducing the pressure gradient through the aortic valve. In our study, we aim to evaluate immediate changes in LV mechanics using intra-procedural transesophageal echocardiography (TEE) to assess circumferential and radial strain via speckle tracking. Intra-operative TEE was performed during TAVI for 53 patients (mean age 84 ± 8 years). Two-dimensional images in the transgastric view were acquired at the level of the papillary muscle. Circumferential and radial strain was calculated using speckle tracking with Philips Qlab software. Global LV afterload was measured by calculating valvulo-arterial impedance (Zva). Immediately post-TAVI, there was a change in both radial strain rate (Pre: 0.73 ± 0.04 vs. Post: 0.88 ± 0.04 per second, P < 0.001) and circumferential strain rate (-0.53 ± 0.04 (pre) vs. -0.74 ± 0.04 (post) per second, P < 0.001). There was also an immediate improvement in circumferential global strain parameters (-14.5 ± 5% (pre) vs. -16.0 ± 4.7% (post), P < 0.05), whereas there was no significant change seen in global radial strain (15.6 ± 0.8% (pre) vs. 15.2 ± 0.9% (post), P = 0.69). No significant change was seen in LV ejection fraction (51.5 ± 14.2% (pre) vs. 52.1 ± 14.0% (post), P = 0.77). Speckle tracking using TEE images is feasible and identifies significant improvements in LV strain and strain rate immediately following TAVI that is not detected by conventional measure of LV function.

Point of care cardiac ultrasound applications in the emergency department and intensive care unit--a review

The use of point of care echocardiography by non-cardiologist in acute care settings such as the emergency department (ED) or the intensive care unit (ICU) is very common. Unlike diagnostic echocardiography, the scope of such point of care exams is often restricted to address the clinical questions raised by the patient's differential diagnosis or chief complaint in order to inform immediate management decisions. In this article, an overview of the most common applications of this focused echocardiography in the ED and ICU is provided. This includes but is not limited to the evaluation of patients experiencing hypotension, cardiac arrest, cardiac trauma, chest pain and patients after cardiac surgery.