Preoperative Point-of-Care Ultrasound to Identify Frailty and Predict Postoperative Outcomes: A Diagnostic Accuracy Study.

BACKGROUND: Frailty is increasingly being recognized as a public health issue, straining healthcare resources and increasing costs to care for these patients. Frailty is the decline in physical and cognitive reserves leading to increased vulnerability to stressors such as surgery or disease states. The goal of this pilot diagnostic accuracy study was to identify whether point-of-care ultrasound measurements of the quadriceps and rectus femoris muscles can be used to discriminate between frail and not-frail patients and predict postoperative outcomes. This study hypothesized that ultrasound could discriminate between frail and not-frail patients before surgery. METHODS: Preoperative ultrasound measurements of the quadriceps and rectus femoris were obtained in patients with previous computed tomography scans. Using the computed tomography scans, psoas muscle area was measured in all patients for comparative purposes. Frailty was identified using the Fried phenotype assessment. Postoperative outcomes included unplanned intensive care unit admission, delirium, intensive care unit length of stay, hospital length of stay, unplanned skilled nursing facility admission, rehospitalization, falls within 30 days, and all-cause 30-day and 1-yr mortality. RESULTS: A total of 32 patients and 20 healthy volunteers were included. Frailty was identified in 18 of the 32 patients. Receiver operating characteristic curve analysis showed that quadriceps depth and psoas muscle area are able to identify frailty (area under the curve-receiver operating characteristic, 0.80 [95% CI, 0.64 to 0.97] and 0.88 [95% CI, 0.76 to 1.00], respectively), whereas the cross-sectional area of the rectus femoris is less promising (area under the curve-receiver operating characteristic, 0.70 [95% CI, 0.49 to 0.91]). Quadriceps depth was also associated with unplanned postoperative skilled nursing facility discharge disposition (area under the curve 0.81 [95% CI, 0.61 to 1.00]) and delirium (area under the curve 0.89 [95% CI, 0.77 to 1.00]). CONCLUSIONS: Similar to computed tomography measurements of psoas muscle area, preoperative ultrasound measurements of quadriceps depth shows promise in discriminating between frail and not-frail patients before surgery. It was also associated with skilled nursing facility admission and postoperative delirium.

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.

Preoperative Three-Dimensional Strain Imaging Identifies Reduction in Left Ventricular Function and Predicts Outcomes After Cardiac Surgery.

BACKGROUND: Echocardiography-based speckle-tracking strain imaging is an emerging modality to assess left ventricular function. The aim of this study was to investigate the change in left ventricular systolic function after cardiac surgery with 3-dimensional (3D) speckle-tracking strain imaging and to determine whether preoperative 3D strain is an independent predictor of acute and long-term clinical outcomes after aortic valve, mitral valve, and coronary artery bypass grafting operations. METHODS: In total, 163 adult patients undergoing aortic valve, mitral valve, and coronary artery bypass surgeries were enrolled prospectively and had complete data sets. Demographic, operative, and outcome data were collected. 3D transthoracic echocardiograms were preformed preoperatively and on second to fourth postoperative day. Blinded off-line analysis was performed for left ventricular 2-dimensional (2D) ejection fraction (EF2D) and 3D ejection fraction (EF3D) and global peak systolic area, longitudinal, circumferential, and radial strain. RESULTS: 3D global strain correlated well with EF3D. Ventricular function as measured by strain imaging decreased significantly after all types of cardiac surgery. When preoperative EF3D was used, receiver operating characteristic curves identified reference values for 3D global strain corresponding to normal, mildly reduced, and severely reduced ventricular function. Normal ventricular function (EF3D ≥ 50%) corresponded to 3D global area strain -25%, with area under curve = 0.86 (0.81-0.89). Patients with reduced preoperative 3D global area strain had worse postoperative outcomes, including length of intensive care unit stay (4 vs 3 days, P = .001), major adverse events (27% vs 11%, P = .03), and decreased 1-year event-free survival (69% vs 88%, P = .005). After we controlled for baseline preoperative risk models including European System for Cardiac Operative Risk Evaluation score and surgery type, preoperative strain was an independent predictor of both short- and long-term outcomes, including length of intensive care unit stay, postoperative inotrope score, and 1-year event-free survival. CONCLUSIONS: This study shows that cardiac surgery was associated with an acute reduction in postoperative left ventricular function, when evaluated with 3D strain imaging. In addition, preoperative 3D strain was demonstrated to be an independent predictor of acute and long-term clinical outcomes after cardiac surgery. The use of noninvasive 3D transthoracic echocardiogram strain imaging before cardiac surgery may provide added information to aid in perioperative risk stratification and management for these high-risk patients.

Speckle-Tracking Strain Imaging Identifies Alterations in Left Atrial Mechanics With General Anesthesia and Positive-Pressure Ventilation.

OBJECTIVES: The primary aim of this study was to use speckle-tracking strain imaging to evaluate the effect of general anesthesia (GA) and positive-pressure ventilation (PPV) on left atrial (LA) mechanics. The authors hypothesized that GA and PPV would be associated with a decrease in LA strain. The secondary aims were to investigate the effects of GA and PPV on traditional Doppler-derived measures of LA function and Doppler echocardiographic grade of diastolic function. DESIGN: A prospective observational study. SETTING: A university hospital. PARTICIPANTS: Adult patients undergoing cardiac surgery. INTERVENTIONS: Transthoracic echocardiography was performed at baseline and under GA with PPV. MEASUREMENTS AND MAIN RESULTS: Changes in LA function associated with GA and PPV were assessed using LA speckle-tracking strain imaging. A reduction was observed in LA peak longitudinal strain (24% v 18%, p<0.001) and preatrial contraction strain (13% v 8%, p<0.001). No difference was seen in LA contraction strain or atrial ejection fraction. Indexed LA volume and Doppler diastolic indices also were reduced significantly, and 39% of patients had a change in measured diastolic grade under GA with PPV. CONCLUSIONS: Speckle-tracking strain imaging of the left atrium demonstrated that GA and PPV had a significant impact on LA mechanics by decreasing strain measures of LA preload, with a lesser effect on LA contractility.

Left ventricular endocardial and epicardial strain changes with apical myocardial ischemia in an open-chest porcine model.

Early detection of acute myocardial ischemia is critical to prevent permanent myocardial damage. The impact of apical ischemia on global left ventricular (LV) function can be difficult to characterize using traditional volume-based echocardiography measures. Myocardial strain imaging is a sensitive, quantitative marker of myocardial deformation that can measure ventricular function. Recent advances allow layer-specific measurement of endo- and epicardial strain, enhancing the ability to evaluate myocardial ischemia. This study investigates the effects of apical ischemia on LV function using epi- and endocardial strain. We hypothesize that myocardial strain will identify changes in regional and global myocardial function associated with focal apical ischemia as compared to ejection fraction (EF), and that longitudinal strain will be a better indicator of myocardial dysfunction compared to circumferential or radial strain. In a porcine model (n = 9), acute ischemia was induced by left anterior descending coronary artery occlusion. Echocardiograms were performed at baseline, during 15-min ischemia, and after reperfusion. Global longitudinal strain decreased with acute focal ischemia of the left ventricular apical region (baseline: -16.4% vs. ischemia: -12.2%; P = 0.010), with no change observed in global circumferential and radial strain or EF Both endocardial and epicardial longitudinal strain decreased by 68% (P < 0.001) in the ischemic and peri-ischemic zone, while circumferential and radial strain only decreased in endocardium of the ischemic zone. Longitudinal strain was more sensitive to ischemia, being able to detect changes in global LV function and thus may confer clinical diagnostic advantage in the evaluation of acute LV apical ischemia.

Novel techniques of mechanical circulatory support for the right heart and Fontan circulation.

BACKGROUND: Currently available ventricular assist devices are designed primarily for use in patients with left sided heart failure. This study evaluated the efficacy of the Jarvik 2000 ventricular assist device (VAD) as a pulmonary pump to power a Fontan circuit in a large animal model. METHODS: Without the use of cardiopulmonary bypass, Fontan circulations were surgically created in 4 pigs (50 kg) using synthetic grafts from the inferior and superior vena cavas to the main pulmonary artery. Subsequently, the VAD was implanted within the common Fontan graft to provide a pulmonary pump. Direct chamber pressures and epicardial Doppler images were taken during the various phases of the experiment. Heart rate, femoral artery blood pressure, oxygen saturation, and aortic flow rate were continuously recorded. The outflow cannula of the VAD was then partially banded by 50% and then 75% to mimic increased afterload. RESULTS: Fontan and VAD implantation was successfully performed in all 4 animals. Arterial pressure and aortic flow decreased dramatically with institution of the Fontan but were restored to baseline upon activation of the VAD. The pressure within the systemic venous circulation rose precipitously with institution of the Fontan circulation and improved appropriately with activation of the VAD. Adequate perfusion was maintained during increased afterload. CONCLUSIONS: An axial flow VAD can restore normal hemodynamics and cardiac output when used as a pulmonary pump in a Fontan circulation. A VAD can rescue a failing Fontan as a bridge to transplant or recovery, even in the setting of high pulmonary resistance.