Transesophageal Echocardiography, 3-Dimensional and Speckle Tracking Together as Sensitive Markers for Early Outcome in Patients With Left Ventricular Dysfunction Undergoing Cardiac Surgery

Left ventricular global longitudinal strain and cardiac surgical outcomes

Global longitudinal strain (GLS) has emerged as a valuable diagnostic and prognostic tool for evaluating left ventricular (LV) function. GLS has been shown to be a more sensitive marker of LV dysfunction than LV ejection fraction alone and have prognostic impact in non-surgical cardiac populations. GLS, is validated, reproducible, and easily obtained from 2-dimensional speckle-tracking echocardiography. While there is strong evidence for using GLS in clinical decision-making in non-surgical populations, there is less summarized evidence on using GLS in the cardiac surgical population. This review combines the evidence on the implications of using baseline transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) GLS in cardiac surgical populations including ischemic and structural heart disease to determine surgical outcomes. We found that results seem promising on the prognostic utility of LV strain in cardiac surgical populations. However due to the variability of study populations and outcomes, and modalities (TTE versus TEE), further research on normal versus abnormal values for different surgical populations, as well potential treatment options that may modify and potentially decrease surgical risk for those with abnormal GLS are needed.

Global longitudinal strain is a better metric than left ventricular ejection fraction: lessons learned from cancer therapeutic-related cardiac dysfunction

PURPOSE OF THE REVIEW

This review aims to highlight the utility of global longitudinal strain (GLS) in cancer therapeutic-related cardiac dysfunction (CTRCD), with an attempt to stipulate that GLS might be a better measure than left ventricular ejection fraction (LVEF).

RECENT FINDINGS

Increasingly, GLS quantification has been employed in various cardiovascular diseases especially with its ability to detect left ventricular dysfunction subclinically, even before a change in LVEF is visualized. In fact, several studies reveal that GLS may be a superior predictor of mortality and morbidity than LVEF in this context. A recent metaanalysis supported the prognosticating value of GLS in CTRCD, however, endorsed the need for larger multicenter studies to establish the value of this metric. Studies in other cardiovascular disease processes showed GLS as a better metric than LVEF.

SUMMARY

GLS has been heralded as a new echocardiographic measure that can detect subclinical cardiac disease. At a minimum, GLS can provide incremental value in prognosticating, diagnosing, and predicting LVEF recovery and at best, a better measure of left ventricular dysfunction.

Regional Left Ventricular Myocardial Dysfunction After Cardiac Surgery Characterized by 3-Dimensional Strain

BACKGROUND

Three-dimensional (3D) strain is an echocardiographic modality that can characterize left ventricular (LV) function with greater accuracy than ejection fraction. While decreases in global strain have been used to predict outcomes after cardiac surgery, changes in regional 3D longitudinal, circumferential, radial, and area strain have not been well described. The primary aim of this study was to define differential patterns in regional LV dysfunction after cardiac surgery using 3D speckle tracking strain imaging. Our secondary aim was to investigate whether changes in regional strain can predict postoperative outcomes, including length of intensive care unit stay and 1-year event-free survival.

METHODS

In this prospective clinical study, demographic, operative, echocardiographic, and clinical outcome data were collected on 182 patients undergoing aortic valve replacement, mitral valve repair or replacement, coronary artery bypass graft, and combined cardiac surgery. Three-dimensional transthoracic echocardiograms were performed preoperatively and on the second to fourth postoperative day. Blinded analysis was performed for LV regional longitudinal, circumferential, radial, and area strain in the 17-segment model.

RESULTS

Regional 3D longitudinal, circumferential, radial, and area strains were associated with differential patterns of myocardial dysfunction, depending on the surgical procedure performed and strain measure. Patients undergoing mitral valve repair or replacement had reduced function in the majority of myocardial segments, followed by coronary artery bypass graft, while patients undergoing aortic valve replacement had reduced function localized only to apical segments. After all types of cardiac surgery, segmental function in apical segments was reduced to a greater extent as compared to basal segments. Greater decrements in regional function were seen in circumferential and area strain, while smaller decrements were observed in longitudinal strain in all surgical patients. Both preoperative regional strain and change in regional strain preoperatively to postoperatively were correlated with reduced 1-year event-free survival, while postoperative strain was not predictive of outcomes. Only preoperative strain values were predictive of intensive care unit length of stay.

CONCLUSIONS

Changes in regional myocardial function, measured by 3D strain, varied by surgical procedure and strain type. Differences in regional LV function, from presurgery to postsurgery, were associated with worsened 1-year event-free survival. These findings suggest that postoperative changes in myocardial function are heterogeneous in nature, depending on the surgical procedure, and that these changes may have long-term impacts on outcome. Therefore, 3D regional strain may be used to identify patients at risk for worsened postoperative outcomes, allowing early interventions to mitigate risk.

Use of speckle-tracking strain in preload-dependent patients, need for cautious interpretation!

BACKGROUND

In critical patients, left ventricular ejection fraction and fractional shortening are used to reflect left ventricular systolic function. An emerging technique, two-dimensional-strain echocardiography, allows assessment of the left ventricle systolic longitudinal deformation (global longitudinal strain) and the speed at which this deformation occurs (systolic strain rate). This technique is of increasing use in critical patients in intensive care units and in the peri-operative period where preload constantly varies. Our objective, in this prospective single-center observational study, was to evaluate the effect of fluid resuscitation on two-dimensional-strain echocardiography measurements in preload-dependent critically ill patients. We included 49 patients with preload dependence attested by an increase of at least 10% in the left ventricular outflow track velocity-time integral measured by echocardiography during a passive leg raising maneuver. Echocardiography was performed before fluid resuscitation (echocardiography 1) and after preload independency achievement (echocardiography 2).

RESULTS

Two-dimensional-strain echocardiography was feasible in 40 (82%) among the 49 patients. With preload dependence correction, the absolute value of global longitudinal strain and systolic strain rate was significantly increased from, respectively, - 13.3 ± 3.5 to - 18.4% ± 4.5 (p < 0.01) and - 1.11 s^-1 ± 0.29 to - 1.55 s^-1 ± 0.55 (p < 0.001). The fluid resuscitation affects GLS and SSR in preload-dependent patients, with a shift, for GLS, from pathological to normal values.

CONCLUSION

In critically ill patients, the assessment of the systolic function by two-dimensional-strain echocardiography needs prior evaluation of preload dependency, in order to adequately interpret this variable. Future studies should assess the ability of global longitudinal strain to guide fluid management in the critically ill patients.