Speckle tracking echocardiography: imaging insights into the aorta

Structural and Functional Disturbances of the Thoracic Aorta in Atherosclerosis of Various Gradations

Aim      To study global aortic circumferential strain in normal conditions and in atherosclerosis of various grades and to determine its role in prediction of structural and functional disorders of the thoracic aorta (TA) and coronary atherosclerosis using 2D speckle-tracking transesophageal echocardiography.Material and methods  182 patients with typical or probable angina were examined. The control group consisted of 11 healthy volunteers. TA was visualized along its entire length. The height of each atheroma was measured, and the total number of plaques in the TA was determined. Five stages of TA atherosclerosis were identified. In the descending TA, the global peak systolic circumferential strain (GCS, %) and the global peak systolic circumferential strain normalized to pulse arterial pressure (PAP) (GCS / PAP∙100) were calculated. All patients underwent coronary angiography. The number of coronary arteries (CAs) with >50 % stenosis was determined, and the SYNTAX Score was calculated.Results TA atherosclerosis was not detected in the control group. Among 182 patients, stage 1-5 TA atherosclerosis was found in 23 (12.6 %), 103 (56.6 %), 43 (23.6 %), 7 (3.8 %), and 6 (3.4 %) cases respectively. GCS and GCS / PAD decreased as the ultrasound stage of TA atherosclerosis increased as compared with the control group: 9.2 % and 15.3 for the control group; stage 1, 5.6 % and 8.9 (p<0.001); stage 2, 4.1 % and 5.9 (p<0.001); stage 3, 4 % and 5.8 (p<0.001); stage 4, 3.7 % and 4.9 (p<0.01); and stage 5, 2.6 % and 3.3 (p<0.01), respectively. ROC analysis showed that GCS ≥5.9 % (area under the curve, AUC, 0.94±0.03; p<0.001) and GCS / PAD ≥11.4 (AUC, 0.97±0.02; p <0.001) were predictors of intact TA. Also, GCS ≤4.85 % (AUC, 0.82±0.04; p<0.001) and GCS / PAD ≤8.06 (AUC, 0.87±0.03; p<0.001) were predictors of hemodynamically significant TA atherosclerosis (stages 3-5). GCS ≤4.05 % (AUC, 0.62±0.04; p=0.007) and GCS / PAD ≤5.95 (AUC, 0.61±0.04; p=0.018) were predictors of hemodynamically significant (>50 %) stenosing atherosclerosis of at least one CA. Furthermore, GCS ≤3.75 % (AUC, 0.67±0.07; p=0.039) and GCS / PAD ≤5.15 (AUC, 0.64±0.07; p=0.045) were predictors of severe and advanced coronary atherosclerosis (SYNTAX Score ≥22).Conclusion      GCS and GCS / PAD are new diagnostic markers of structural and functional disorders of TA in atherosclerosis of various grades. GCS and GCS / PAD are independent predictors of high-grade TA atherosclerosis (stages 3-5) with GCS / PAD demonstrating the highest level of significance. GCS and GCS / PAD are non-invasive predictors of severe and advanced CA atherosclerosis.

Distal aortic biomechanics after transcatheter versus surgical aortic valve replacement: a hypothesis generating study

BACKGROUND

Biomechanical effects of transcatheter (TAVR) versus surgical (SAVR) aortic valve interventions on the distal aorta have not been studied. This study utilized global circumferential strain (GCS) to assess post-procedural biomechanics changes in the descending aorta after TAVR versus SAVR.

METHODS

Patients undergoing TAVR or SAVR for aortic stenosis were included. Transesophageal (TEE) and transthoracic (TTE) echocardiography short-axis images of the aorta were used to image the descending aorta immediately before and after interventions. Image analysis was performed with two-dimensional speckle tracking echocardiography and dedicated software. Delta GCS was calculated as: post-procedural GCS-pre-procedural GCS. Percentage delta GCS was calculated as: (delta GCS/pre-procedural GCS) × 100.

RESULTS

Eighty patients, 40 TAVR (median age 81 y/o, 40% female) and 40 SAVR (median 72 y/o, 30% female) were included. The post-procedure GCS was significantly higher than the pre-procedural GCS in the TAVR (median 10.7 [interquartile range IQR 4.5, 14.6] vs. 17.0 [IQR 6.1, 20.9], p = 0.009) but not in the SAVR group (4.4 [IQR 3.3, 5.3] vs. 4.7 [IQR 3.9, 5.6], p = 0.3). The delta GCS and the percentage delta GCS were both significantly higher in the TAVR versus SAVR group (2.8% [IQR 1.4, 6] vs. 0.15% [IQR - 0.6, 1.5], p < 0.001; and 28.8% [IQR 14.6%, 64.6%] vs. 4.4% [IQR - 10.6%, 5.6%], p = 0.006). Results were consistent after multivariable adjustment for key clinical and hemodynamic characteristics.

CONCLUSIONS

After TAVR, there was a significantly larger increase in GCS in the distal aorta compared to SAVR. This may impact descending aortic remodeling and long-term risk of aortic events.

Aortic Biomechanics and Clinical Applications

The aorta contributes to cardiovascular physiology and function. Understanding biomechanics in health, disease, and after aortic interventions will facilitate optimization of perioperative patient care.

Evaluation of Ascending Aortic Longitudinal Strain Via Two-Dimensional Speckle Tracking Echocardiography in Hypertensive Patients Complicated by Type A Aortic Dissection

OBJECTIVE

To explore the value of ascending aortic longitudinal strain (LS) in identification of hypertensive (HP) patients with a high risk of type A aortic dissection (AAD).

METHODS

Total 40 primary HP patients with AAD (group C), 80 selected age- and sex-matched primary HP patients (group A, normal-sized ascending aorta (AA), n = 40; group B, dilated AA, n = 40) and 40 healthy volunteers were enrolled in this study. Brachial blood pressures were measured, and the aortic stiffness index (β) determined by M-mode analysis was calculated as a conventional parameter of arterial stiffness. The LS of the anterior and posterior ascending aortic wall (AW-LS and PW-LS) were determined.

RESULTS

Compared to the control group (34.21 ± 5.25%), the mean LS of AA in HP patients (group A 28.6 ± 5.95%; group B 23.64 ± 4.98%; group C 17.93 ± 3.96%; P < .001) were significantly reduced. Multivariate logistic regression analysis showed that the mean LS (OR 0.719, 95% CI 0.615-0.839, P < .001) and pulse pressure (PP) (OR 1.055, 95% CI 1.006-1.106, P = .028) were identified as independent predictors of AAD in HP patients. The AUC of mean LS combined with PP reached 0.926 (sensitivity, 95.0%; specificity, 82.5%), which was higher than the mean LS, PP, stiffness index, and ascending aortic diameter (AAd) separately. Besides, the AW-LS and PW-LS were negatively correlated with the AAd, stiffness index, stroke volume, systolic blood pressure, and PP, respectively (P < .001).

CONCLUSION

The LS of AA evaluated by two-dimensional speckle tracking echocardiography decreased significantly along with the expansion of aortic lumen and the occurrence of AAD in HP patients. It is also an independent predictor of AAD in HP patients.

Assessment of the Global and Regional Circumferential Strain of Abdominal Aortic Aneurysm with Different Size by Speckle-Tracking Echocardiography

OBJECTIVES

We aimed to use speckle-tracking echocardiography (STE) to quantify circumferential aortic strain of abdominal aortic aneurysms (AAA) with different size.

METHODS

A total of 87 AAA patients were included. The morphological variables, including aortic maximum diameter (MD), end systolic area (ESA), end diastolic area (EDA), and thickness and area of intraluminal thrombus (ILT), were measured by ultrasound. STE was applied to calculate circumferential strain (CS) at 6 equally divided segments of the aorta at MD. We evaluated the mean value of peak strain along the 6 segments as global circumferential strain (GCS).

RESULTS

Large AAA (≥5.5 cm) patients had higher MD, ESA, EDA, AAA length, ILT thickness, and area, but lower fractional area change, GCS, and segmental CSs than small AAA (<5.5 cm) subjects (all P < .05). Compared with AAA <4.5 cm group, AAA patients ≥4.5 cm possessed increased MD, ESA, EDA, AAA length, ILT thickness, and area, which results were also reflected in the comparison between AAA <6.5 and ≥6.5 cm group. In small AAA patients, GCS and regional strains in CS1, CS3, and CS5 segments were lower in AAA subjects ≥4.5 cm than those <4.5 cm (all P<.05). However, no significant differences in the GCS and regional CS between ≥6.5 and <6.5 cm group were found. Correlation analysis revealed a significant negative association of GCS with MD, ESA, and EDA, even after adjusting the potential confounding factors (all P < .05).

CONCLUSIONS

Our findings may yield insight into the structural strain characteristics of AAA wall with different size, which adds the benefit of using simple echocardiography-derived biomechanics to stratify AAA patients.

The Progress of Advanced Ultrasonography in Assessing Aortic Stiffness and the Application Discrepancy between Humans and Rodents

Aortic stiffening is a fundamental pathological alteration of atherosclerosis and other various aging-associated vascular diseases, and it is also an independent risk factor of cardiovascular morbidity and mortality. Ultrasonography is a critical non-invasive method widely used in assessing aortic structure, function, and hemodynamics in humans, playing a crucial role in predicting the pathogenesis and adverse outcomes of vascular diseases. However, its applications in rodent models remain relatively limited, hindering the progress of the research. Here, we summarized the progress of the advanced ultrasonographic techniques applied in evaluating aortic stiffness. With multiple illustrative images, we mainly characterized various ultrasound techniques in assessing aortic stiffness based on the alterations of aortic structure, hemodynamics, and tissue motion. We also discussed the discrepancy of their applications in humans and rodents and explored the potential optimized strategies in the experimental research with animal models. This updated information would help to better understand the nature of ultrasound techniques and provide a valuable prospect for their applications in assessing aortic stiffness in basic science research, particularly with small animals.

Differential Effects of Aortic Valve Replacement on Aortic Circumferential Strain in Aortic Stenosis and Aortic Insufficiency

OBJECTIVES

Aortic valve replacement (AVR) potentially can modify pulse-wave propagation to the distal aorta. Echo-derived global circumferential strain (GCS) was used to test whether AVR for aortic stenosis (AS) or aortic insufficiency (AI) resulted in differential aortic biomechanics in the descending thoracic aorta.

DESIGN

This was a prospective observational study of patients who underwent cardiac surgery between 2016 and 2019.

SETTING

Weill Cornell Medicine, a single large academic medical center.

PARTICIPANTS

The population comprised 48 patients undergoing AVR (62 ± 15 y/o, 79% male; 22 with AI and 26 with AS) and 11 patients undergoing coronary bypass surgery as controls.

INTERVENTIONS

Elective cardiac surgery, transesophageal echocardiography (TEE), pulmonary artery catheter.

MEASUREMENTS AND MAIN RESULTS

Pre- and postprocedural TEEs were collected. Descending aorta short-axis images were analyzed for GCS, time-to-peak strain, aortic end-diastolic, end-systolic area, and fractional area changes. Pulse pressure (PP) and stroke volume were quantified. Preprocedural GCS significantly differed between patients with AI and AS, with AI patients having greater GCS (median/interquartile range, 9.6 95.3,13.6) than patients with AS (4.3 [3.4-5.1]). After AVR, in AI patients, strain significantly decreased (5.5 [3.8,8.2], p = 0.001), along with PP (mean ± standard deviation) (66.4 ± 0.8 to 54.1 ± 13.7, p < 0.001), and PP corrected strain did not (GCS/PP = 14.8 [6.9-19.9] v 12.7[8.2-18.6], p = 0.34). In AS patients, GCS significantly increased after AVR to (5.45 [4.2-6.8], p = 0.003), as did PP-corrected strain (6.9 [5.8-9.2] v 9.7 [6.5-13.4], p = 0.016). Surgical AVR produced decrements in time-to-peak strain in AI and AS groups (both p < 0.001).

CONCLUSIONS

After AVR for AI and AS, the direction of change in distal aortic strain from baseline depends on valve pathology. This finding may have important clinical implications in terms of indication for surgery and postoperative surveillance, especially in patients with aortopathies.

Descending aortic strain quantification by intra-operative transesophageal echocardiography: Multimodality validation via cardiovascular magnetic resonance

BACKGROUND

Whereas cardiac magnetic resonance (CMR) imaging provides high temporal resolution imaging of aortic distensibility (strain), transesophageal echocardiography (TEE) is widely used for intra-operative aortic imaging and provides a clinical alternative for aortic assessment. We tested intra-operative global circumferential aortic strain (GCS) measured on TEE in relation to the reference of CMR-derived strain among patients undergoing surgical graft repair of ascending aortic aneurysms.

METHODS

CMR (3T) was prospectively performed in patients scheduled for aortic repair. TEE was performed intra-operatively; images were co-localized with MRI. GCS on CMR and TEE was quantified independently, blinded to results of the other modality.

RESULTS

25 patients (54 ± 10 year-old, 88% male) were studied, inclusive of 13 genetically mediated and 12 degenerative aneurysms: CMR and TEE were performed within 12 ± 9 days. Pulse pressure (PP)-adjusted descending aortic TEE-derived GCS strongly correlated with cine-CMR-derived GCS (r = .75, P = .002) though absolute GCS and PP-adjusted values were slightly lower (5.40 ± 1.11 vs 6.49 ± 1.43% and 11.55 ± 3.04 vs 13.99 ± 4.53%, respectively). Similarly, TEE yielded slightly lower end-diastolic area (EDA [5.1 ± 1.7 cm² vs 5.8 ± 1.3 cm² , P = .004]) and end-systolic area (ESA [6.1 ± 1.9 cm² vs 6.5 ± 1.7 cm² , P = .10]), with significant correlations between the two modalities (r = .73, .76, P < .05 for all).

CONCLUSIONS

This exploratory study supports feasibility of TEE for assessing aortic GCS in a surgical at-risk population, as well as magnitude of agreement between intra-operative TEE and preoperative CMR. We found that there is a significant correlation between GCS and EDA and ESA aortic areas, but that TEE-derived parameters underestimated CMR values by a small but significant amount.