Prognostic significance of dobutamine stress echocardiography in patients with chronic kidney disease and known or suspected coronary artery disease: a 5-year follow-up study.

Dobutamine stress echocardiography (DSE) is an effective noninvasive modality for evaluating coronary artery disease (CAD), with high accuracy. However, data on the prognostic value of DSE in patients with chronic kidney disease (CKD) are limited. This study aims to assess the prognostic significance of DSE in patients with CKD and known or suspected CAD. We included consecutive patients with CKD stage 3 or higher and known or suspected CAD who underwent clinically indicated DSE between 2007 and 2017. The primary endpoint was all-cause mortality at 5 years. Univariable and multivariable analyses were conducted to identify predictors of all-cause mortality, with a p value < 0.05 considered statistically significant. A total of 274 patients were included in the study. The mean age was 64.0 ± 13.1 years, with 54% being male and 13.1% having known CAD. Among the patients, 64.6% had advanced CKD (≥ stage 4). Abnormal DSE was observed in 62 patients (22.6%). During a follow-up period of 7.0 ± 3.5 years, 78 patients (28.5%) died. The mortality rate was significantly higher in patients with abnormal DSE compared to those with normal DSE (48.4% vs. 22.6%, p < 0.001). Multivariable analysis identified age (hazard ratio [HR] 1.03, 95% confidence interval [CI] 1.008-1.05, p = 0.005), New York Heart Association (NYHA) functional class (HR 1.60, 95% CI 1.05-2.43, p = 0.03), and chronotropic index < 0.73 (HR 2.61, 95% CI 1.60-4.25, p < 0.001) as independent predictors of mortality. Conversely, a normal DSE result was found to be a protective factor (HR 0.49, 95% CI 0.30-0.81, p = 0.005). In conclusion, DSE demonstrated significant prognostic value in patients with CKD and known or suspected CAD. Age, NYHA functional class, and a chronotropic index < 0.73 were identified as independent predictors of all-cause mortality.

Three-dimensional anatomic features of the mitral valve that predict systolic anterior motion occurring during dobutamine stress echocardiography.

BACKGROUND/AIM: Left ventricular outflow tract obstruction related to systolic anterior motion (SAM) of the mitral valve is a common complication of dobutamine stress echocardiography (DSE). However, the mechanisms underlying SAM have not been fully characterized. The objective of the present study was to use three-dimensional echocardiography to identify anatomic features of the mitral valve that predispose to SAM during DSE. METHODS: We retrospectively evaluated consecutive patients included prospectively in our database and who had undergone 3D echocardiography (including an assessment of the mitral valve) before DSE. Patients who had developed SAM during DSE (the SAM+ group) were matched 2:3 with patients who did not (the SAM- group). RESULTS: One hundred patients were included (mean age: 67 ± 10). Compared with SAM- patients (n = 60), SAM+ patients (n = 40) had a lower mitral annular area, a smaller perimeter, and a smaller diameter (p < .01 for all, except the anteroposterior diameter). The SAM+ group had also a narrower mitral-aortic angle (126 ± 12° vs. 139 ± 11° in the SAM- group; p < .01) and a higher posterior mitral leaflet length (1.4 ± .27 cm vs. 1.25 ± .29, respectively; p < .01). Furthermore, the mitral annulus was more spherical, more flexible, and more dynamic in SAM+ patients than in SAM- patients (p < .05 for all). In a multivariate analysis of anatomic variables, the mitral-aortic angle, the mitral annular area, and posterior leaflet length were independent predictors of SAM (p ≤ .01 for all). In a multivariate analysis of standard echo and hemodynamic variables, the presence of wall motion abnormalities at rest (p < .01) was an independent predictor of SAM. CONCLUSION: SAM during DSE is multifactorial. In addition to the pharmacologic effects of dobutamine on the myocardium, 3D echocardiographic features of the mitral valve (a smaller mitral annulus, a narrower mitral-aortic angle, and a longer posterior leaflet) appear to predispose to SAM.

Prognostic value of transvalvular flow rate in patients with low-gradient severe aortic stenosis: A dobutamine stress echocardiography study.

BACKGROUNDS: There are limited data on the clinical relevance of transvalvular flow rate (Qmean ) at rest (Qrest) and at peak stress (Qstress ) during dobutamine stress echocardiography (DSE) in patients with low-gradient severe aortic stenosis (LG-SAS). METHODS: We retrospectively analyzed the clinical data of patients with LG-SAS who underwent DSE. LG-SAS was defined as an aortic valve (AV) area index of < .6 cm2 /m2 and a mean AV pressure gradient (AVPG) of < 40 mm Hg. The primary endpoint included all-cause death and heart failure hospitalization. RESULTS: Of 100 patients (mean age 79.5 ± 7.3 years; men, 45.0%; resting left ventricular ejection fraction [LVEF] 52.1% ± 15.9%; resting stroke volume index 35.8 ± 7.7 mL/m2 ; Qrest 171.8 ± 34.9 mL/s), the primary endpoint occurred in 51 patients during a median follow-up of 2.84 (interquartile range 1.01-5.21) years. When the study patients were divided into three subgroups based on Qrest and Qstress , the multivariate analysis showed that Qrest < 200 mL/s and Qstress ≥200 mL/s (hazard ratio 3.844; 95% confidence interval 1.143-12.930; p = .030), as well as Qrest and Qstress < 200 mL/s (hazard ratio 9.444; 95% confidence interval 2.420-36.850; p = .001), were significantly associated with unfavorable outcomes with Qrest and Qstress ≥200 mL/s as a reference after adjusting for resting LVEF, resting mean AVPG, chronic kidney disease, New York Heart Association functional class III/IV, and AV replacement. CONCLUSIONS: Flow conditions based on the combination of Qrest and Qstress are helpful for risk stratification in LG-SAS patients.

Quantitative evaluation of myocardial perfusion in coronary heart disease by myocardial contrast and dobutamine stress echocardiography.

OBJECTIVE: We aimed to investigate how combining myocardial contrast echocardiography (MCE) with dobutamine stress echocardiography (DSE) could help evaluate myocardial perfusion in coronary heart disease patients and understand changes in microcirculation across different levels of coronary artery blockage. METHODS: We conducted MCE and DSE tests on 53 coronary heart disease patients, categorizing ischemic myocardium into four groups: A (<50%), B (50%-69%), C (70%-89%), and D (≥90%). Dynamic myocardial perfusion images were captured during rest and peak dobutamine stress from various angles, analyzing parameters like plateau value A, slope ß, and the product A × ß, reflecting different aspects of myocardial blood flow. RESULTS: Parametric values of myocardial perfusion (PVMPs) were significantly lower in group D at rest compared with other groups (p < 0.001). PVMPs increased notably at peak dobutamine stress in groups A, B, and C (p < 0.001). Groups A and B had higher PVMPs than groups C and D, with group D significantly lower (p < 0.001). ß reserve values decreased gradually from group A to D, with significantly lower values of A and A × ß in groups C and D compared with A and B (p < 0.001). Sensitivity and specificity for predicting >70% coronary artery blockage was 80%, 66%, and 74%, 80%, respectively, using specific thresholds. CONCLUSION: Combining MCE with DSE is highly sensitive and accurate in diagnosing obstructive coronary artery blockages. It also helps assess myocardial microcirculation perfusion and left ventricular reserve function, which decline with increasing severity of coronary artery blockage.

Major impact of vitamin D3 deficiency and supplementation on left ventricular torsional mechanics during dobutamine stress in uncomplicated type 2 diabetes.

BACKGROUND AND AIMS: Hypovitaminosis D is associated with the risk of diabetic complications. Its role in diabetic-related cardiac abnormalities remain poorly understood. We aimed therefore to evaluate the effect of vitamin D deficiency and supplementation on early left ventricular (LV) dysfunction in vitamin D deficient patients with uncomplicated T2D. METHODS AND RESULTS: Sixty-three consecutive T2D patients who had a diagnosis of vitamin D3 were prospectively recruited and allocated into 2 groups (25(OH)D < 20 ng/mL: VDD, >20 ng/mL VDND). Twenty-eight of them with 25(OH)D < 20 ng/mL benefited from a 3-month supplementation. At baseline and follow-up, after conventional echocardiography including evaluation of epicardial adipose tissue (EAT), both LV longitudinal (LS) and circumferential (CS) strains and rotation/twist mechanics were evaluated at rest and during dobutamine (DOB) stress. After treatment, T2D patients successfully normalized their 25(OH)D levels. The strongest associations between vitamin D deficiency and supplementation with LV myocardial function were noticed for torsional mechanics indexes under DOB. EAT correlated significantly (p < 0.01) with baseline 25(OH)D and was reduced after supplementation. Significant correlations were obtained between these 2 parameters with twist or apical rotation at baseline (p < 0.01) and between their delta changes at follow-up (p < 0.01) under DOB. Significant improvements in LS and CS (p < 0.05) under DOB were also underlined at follow-up, with major enhancements noticed in the apical region (p < 0.01) of the LV. CONCLUSIONS: This study provides the first evidences of the potential of vitamin D supplementation as an efficient prophylactic strategy to alleviate the progression of myocardial dysfunction in asymptomatic patients with uncomplicated T2D. CLINICALTRIALS: NCT03437421.

Prognostic value of extended cardiac risk assessment before elective open abdominal aortic surgery.

BACKGROUND: Major vascular surgery is associated with a high perioperative risk and significant mortality. Despite advances in risk stratification, monitoring, and management of perioperative complications, cardiac complications are still common. Stress echocardiography is well established in coronary artery disease diagnostics; however, its prognostic value before high-risk aortic surgery is unknown. This prospective, single-center study compared the outcome of patients undergoing extended cardiac risk assessment before open abdominal aortic surgery with the outcome of patients who had received standard preoperative assessment. METHODS: The study included patients undergoing elective open abdominal aortic surgery. Patients who underwent standard preoperative assessment before the start of a dedicated protocol were compared with patients who had extended cardiac risk assessment, including dobutamine stress echocardiography, as part of a stepwise interdisciplinary cardiovascular team approach. The combined primary endpoint was cardiovascular death, myocardial infarction, emergency coronary revascularization, and life-threatening arrhythmia within 30 days. The secondary endpoint was acute renal failure and severe bleeding. RESULTS: In total, 77 patients (mean age 68.1 ± 8.1 years, 70% male) were included: 39 underwent standard and 38 underwent cardiac risk assessment. The combined primary endpoint was reached significantly more often in patients before than after implementation of the extended cardiac stratification procedure (15% vs. 0%, p = 0.025). The combined secondary endpoint did not differ between the groups. CONCLUSIONS: Patients with extended cardiac risk assessment undergoing elective open abdominal aortic surgery had better 30-day outcomes than did those who had standard preoperative assessment.

Physical and physiological effects of dobutamine stress echocardiography in low-gradient aortic stenosis.

Dobutamine stress echocardiography (DSE) is a useful tool for assessing low-gradient significant aortic stenosis (AS) and contractile reserve (CR), but its prognostic utility has become controversial in recent studies. We evaluated the impact of DSE on aortic valve physiological, structural, and left ventricular parameters in low-gradient AS. Consecutive patients undergoing DSE for low-gradient AS evaluation from September 2010 to July 2016 were retrospectively studied, and DSE findings were divided into four groups: with and without severe AS and/or CR. Relationships between left ventricular chamber quantification, CR, aortic valve Doppler during DSE, and calcium score [by computerized tomography (CT)] were analyzed. There were 258 DSE studies performed on 243 patients, mean age 77.6 ± 10.8 yr and 183 (70.1%) were males. With increasing dobutamine dose, apart from systolic blood pressure, left ventricular ejection fraction, flow, cardiac power output, and longitudinal strain magnitude, along with aortic valve area and mean aortic gradient were all significantly increased (P < 0.05). Flow and mean gradient increased in both the presence and absence of CR, whereas stroke volume and aortic valve area increased mainly in those with CR only. The aortic valve area increased in both patients with low and high calcium scores; however, the baseline area was lower in those with a higher calcium score. During DSE, aortic valve area increases with increase in aortic valve gradient. Higher calcium score is associated with lower baseline aortic valve area, but the aortic valve area still increases with dobutamine even in presence of a high calcium score.NEW & NOTEWORTHY We show that even in most severe aortic stenosis, there is some residual valve pliability. This suggests that a complete loss of pliability is not compatible with survival.

Assessing the future risks of subsequent pregnancies in peripartum cardiomyopathy.

Peripartum cardiomyopathy is a myocardial disease process which occurs in young women either in late pregnancy or the early postpartum period. Due to the young age of women effected by this disease, many of these patients elect to pursue a subsequent pregnancy after their initial diagnosis. Currently, echocardiography is used to better elucidate the cardiovascular risks these young patients face when undergoing a subsequent pregnancy; however, the most accurate modality to determine these risks is debatable. In this review, we explore the current literature regarding the use and accuracy of resting transthoracic echocardiography, exercise stress echocardiography, and dobutamine stress echocardiography in risk stratification of a subsequent pregnancy in a patient with peripartum cardiomyopathy.

Prognostic implication of myocardial perfusion and contractile reserve in end-stage renal disease: A direct comparison of myocardial perfusion scintigraphy and dobutamine stress echocardiography.

BACKGROUND: We aimed to compare the prognostic value of myocardial perfusion scintigraphy (MPS) and dobutamine stress echocardiography (DSE) in patients with end-stage renal disease (ESRD) without known coronary artery disease. METHODS: Two-hundred twenty-nine ESRD patients who applied for kidney transplantation at our centre were prospectively evaluated by MPS and DSE. The primary endpoint was a composite of myocardial infarction (MI) or all-cause mortality. The secondary endpoint included MI or coronary revascularization (CR) not triggered by MPS or DSE at baseline. RESULTS: MPS detected reversible ischemia in 31 patients (13.5%) and fixed perfusion defects in 13 (5.7%) patients. DSE discovered stress-induced wall motion abnormalities (WMAs) in 28 (12.2%) and at rest in 18 (7.9%) patients. MPS and DSE results agreed in 85.6% regarding reversible defects (κ = 0.358; P < .001) and in 90.8% regarding fixed defects (κ = 0.275; P < .001). Coronary angiography detected relevant stenosis > 50% in only 15 of 38 patients (39.5%) with pathological findings in MPS and/or DSE. At a median follow-up of 8 years and 10 months, the primary endpoint occurred in 70 patients (30.6%) and the secondary endpoint in 24 patients (10.5%). The adjusted Cox hazard ratios (HRs) for the primary endpoint were 1.77 (95% CI 1.02-3.08; P = .043) for perfusion defects in MPS and 1.36 (95% CI 0.78-2.37; P = ns) for WMA in DSE. The secondary endpoint was significantly correlated with the findings of both modalities, MPS (HR 3.21; 95% CI 1.35-7.61; P = .008) and DSE (HR 2.67; 95% CI 1.15-6.20; P = .022). CONCLUSION: Perfusion defects in MPS are a stronger determinant of all-cause mortality, MI and the need for future CR compared with WMAs in DSE. Given the complementary functional information provided by MPS vs DSE, results are sometimes contradictory, which may indicate differences in the underlying pathophysiology.

Utility of dobutamine stress echocardiography in aortic valve regurgitation and reduced left ventricular function.

OBJECTIVE: Predictors for post-operative reverse remodeling in patients with severe aortic regurgitation (AR) and reduced left ventricular ejection fraction (LVEF) are unknown. We performed low-dose dobutamine stress echocardiography (DSE) in patients with severe AR and reduced LVEF to evaluate the relationship between contractile reserve (CR) and reverse remodeling after surgery. METHODS: In 31 patients with chronic severe AR and reduced LVEF (LVEF < 50%), we performed pre-operative DSE, assessed CR, and examined whether changes in preoperative DSE were associated with improvement of post-operative LVEF after aortic valve surgery. RESULTS: The pre-operative echocardiographic findings were as follows: left ventricular (LV) end-diastolic dimension: 67 ± 10 mm, LV end-systolic dimension: 52 ± 13 mm, and LVEF: 42 ± 8%. All patients underwent aortic valve surgery. Patients with pre-operative LVEF of ≥45% exhibited a significant increase in LVEF; however, patients with pre-operative LVEF of <45% showed no significant change. When we examined the results of DSE performed in patients with pre-operative LVEF of <45%, ΔLVEF of ≥6% (with CR) during DSE was related to an improvement in post-operative LVEF; ΔLVEF of ≥6% during DSE predicted an improvement in post-operative LVEF, with sensitivity 100%; specificity 78%; and area under curve (AUC) .92. CONCLUSIONS: DSE might be a helpful tool for predicting post-operative reverse remodeling in patients with severe AR and moderately reduced LVEF.

Comparative feasibility of dobutamine stress echocardiography performed with and without intravenous contrast in patients with class III obesity.

BACKGROUND: Concern exists regarding adequacy of visualization of stress echocardiograms performed without intravenous contrast in persons with Class III obesity (body mass index ≥ 40 kg/m2 ). METHODS: Dobutamine stress echocardiography (DSE) was performed on 128 candidates for bariatric surgery with class III obesity without chest pain or pre-existent coronary artery disease (CAD). DSE without intravenous contrast was initially performed on 62 patients with class III obesity, then was subsequently was performed with intravenous contrast on 66 patients with class III obesity. Left ventricular (LV) regional wall motion was assessed at baseline and peak stress using the 16-segment model. RESULTS: In the intravenous contrast group, 1046 of 1056 LV segments studied (99.1%) were well-visualized and interpretable at baseline and 1044 of 1056 LV segments studied (98.9%) were well-visualized and interpretable at peak stress. In the non-contrast group, 905 of 992 segments studied (91.2%) were well-visualized and interpretable at baseline and 886 of 992 segments studied (89.3%) were well-visualized and interpretable at peak stress. A significantly greater number of LV segments were well-visualized and interpretable in the intravenous contrast group than in the group compared to the non-contrast group, at baseline and at peak stress (p < 0.00001 for both). DSE was positive for ischemia in one patient. All patients underwent bariatric surgery without cardiovascular complications. Six months after surgery, all patients were alive; none developed cardiovascular events. CONCLUSION: The use of intravenous contrast during DSE significantly improves visualization and interpretability of LV segments in patients with class III obesity.

Unequivocal interpretation of dobutamine stress echocardiography in low-flow, low-gradient aortic stenosis by right parasternal view.

We present the case of a 77-years-old man with aortic valve stenosis (AS) and reduced left ventricular ejection fraction, in whom right parasternal view provided the best hemodynamic evaluation of AS severity during dobutamine stress echocardiography.

Usefulness of Stress Echocardiography in Assessment of Dynamic Left Ventricular Obstructions: Case Series and Review of the Literature.

Dynamic left ventricular outflow tract obstruction (DLVOTO) or midcavity obstruction in patients with structurally normal hearts is not uncommon in routine clinical practice and can cause significant symptoms mimicking coronary artery disease or heart failure. Although exercise echocardiography is the gold standard for assessing DLVOTO, dobutamine stress echocardiography (DSE) may be valuable diagnostic modality in patients who are unable to exercise or have an uninterpretable 12-lead electrocardiogram. We provide an updated overview of the relevant literature regarding prevalence, pathophysiology, clinical significance, and prognostic impact of DLVOTO and midcavity obstruction in structurally normal hearts. We also present a clinical series of 4 cases of DLVOTO and midcavity obstruction documented by DSE and discuss the value of different kinds of modern stress imaging modalities involving: (1) contrast-enhanced DSE to assess myocardial perfusion and inducible ischemia; (2) adenosine stress echocardiography to assess coronary flow reserve/microvascular dysfunction; and (3) functional imaging with deformation echocardiography to assess subclinical myocardial dysfunction in patients with structurally normal heart and without significant coronary disease. Based upon our own experiences and a critical review of the current literature, we will then present a practical guidance for management of DLVOTO and midcavity obstruction.

Resting echocardiographic predictors for true-severe aortic stenosis in patients with low-gradient severe aortic stenosis: A dobutamine stress echocardiography study.

OBJECTIVE: Dobutamine stress echocardiography (DSE) is not always feasible in patients with low-gradient severe aortic stenosis (LG-SAS), and there are limited data available on the resting echocardiographic predictors for true-severe aortic stenosis (TSAS). This study investigated resting echocardiographic predictors for TSAS. METHODS: Clinical data of 106 LG-SAS patients who underwent DSE were retrospectively analyzed. LG-SAS was defined as an aortic valve area index (AVAi) < .6 cm2 /m2 , and a mean AV pressure gradient < 40 mm Hg. The velocity ratio (VR) was calculated as the peak left ventricular outflow tract velocity/peak AV velocity. TSAS was defined as a projected AVAi < .6 cm2 /m2 . RESULTS: The mean age was 79.3 ± 7.3 years, and 45 (42.5%) were men. The resting AV data were as follows: AVAi, .50 ± .07 cm2 /m2 ; mean AV pressure gradient, 23.0 ± 7.4 mm Hg; and VR, .25 ± .05. The projected AVAi was .58 ± .09 cm2 /m2 , and TSAS was documented in 65 (61.3%) patients. In multivariate analysis, the independent predictors of TSAS were AVAi (p = 0.012) and VR (p = 0.004) with respective best cut-off values of .52 cm2 /m2 and .25 on receiver-operating characteristic curve analysis. According to incremental numbers of the predictors, correct classification percentages of TSAS significantly increased with the Cochran-Armitage trend test (16.2% in no predictors, 65.2% in one predictor, and 95.7 % in two predictors; p < 0.001). CONCLUSIONS: Resting AVAi and VR were independent predictors of TSAS in LG-SAS patients. The true severity might be predictable using the combination of resting parameters.

Safety and feasibility of dobutamine stress echocardiography in symptomatic high gradient aortic stenosis patients scheduled for transcatheter aortic valve implantation.

PURPOSE: We aimed to study the safety and feasibility of low-dose dobutamine stress echocardiography in a symptomatic high gradient aortic stenosis population scheduled for transfemoral transcatheter aortic valve implantation (TAVI) and to quantify left ventricular (LV) flow reserve. METHODS: Fifty patients underwent dobutamine stress echocardiography with 5 minutes increments of 5 µg/kg/min up to 20 µg/kg/min until the heart rate increased ≥20 beats/min from baseline or exceeded 100 beats/min. Other criteria for discontinuing the infusion were major adverse events: ventricular arrhythmia, persistent supraventricular arrhythmia, pulmonary edema, chest pain with significant ST-changes, or minor events: ST-changes, drop in systolic blood pressure >30 mmHg, mild chest pain, and/or dyspnea. LV flow reserve was defined as an increase in stroke volume ≥20% during the test. RESULTS: Of 50 patients, 45 completed the test according to protocol. No patient had major adverse event. Five patients experienced minor side effects: mild chest pain/dyspnea in three, self-terminating atrial flutter in one, and decrease in blood pressure in one. Significant LV flow reserve was observed in 20 patients (40%). CONCLUSION: Low-dose dobutamine stress test appeared safe and feasible patients with high gradient aortic stenosis, and showed LV flow reserve in a minority of them.

Intravascular ultrasound-guided selection for early noninvasive cardiac allograft vasculopathy screening in heart transplant recipients.

BACKGROUND: Noninvasive screening for cardiac allograft vasculopathy (CAV) instead of invasive coronary angiography (ICA) within the first 3 to 5 years after heart transplantation (HTx) is controversial. We evaluated a strategy of intravascular ultrasound (IVUS)-guided conversion to early noninvasive screening post-HTx. METHODS: A single-center study of 103 consecutive HTx recipients from 2008 to 2018 undergoing ICA at 1 year post-HTx. Of 88 patients with normal 1-year ICA, sixty-six patients underwent IVUS examination for risk stratification by maximal intimal thickness (MIT) into (i) low-risk group (MIT < 0.5 mm) (n = 41, 62%) followed noninvasively versus (ii) high-risk group (MIT ≥ 0.5 mm) (n = 25, 38%) followed with yearly ICA. Both groups underwent ICA at year 5 post-HTx. We evaluated a combined endpoint of angiographic CAV and death at 5-year follow-up post-HTx. RESULTS: Median (IQR) age was 51 (33-60) years, and 62% were male. Follow-up was 1443 (1125-1456) days. Survival free from angiographic CAV (Kaplan-Meier) differed significantly between groups (log-rank p < .0001). A subgroup of 27 patients completed ICA at year 5, and the proportion of angiographic CAV was significantly lower in low-risk patients (p < .0001). CONCLUSION: IVUS-guided selection for early noninvasive CAV screening appears to be safe and holds promise as a novel strategy for early risk stratification and CAV surveillance post-HTx.

The clinical significance of the incorporation of tissue Doppler imaging into low-dose Dobutamine stress echocardiography in patients with aortic stenosis prior to Transcatheter aortic valve implantation.

BACKGROUND: Low-dose dobutamine stress echocardiography (DSE) is indicated in patients with low flow (stroke volume index [SVi] < 35 ml/m2) low gradient (mean pressure gradient < 40 mmHg) and left ventricular ejection fraction (LVEF) < 50% aortic stenosis (AS) to assess LV contractile reserve (> 20% increase in SVi) and severity grade of AS. Severe AS is defined by a mean pressure gradient of 40 mmHg occurring at any time during the test when aortic valve area remains < 1.0 cm2. CASE PRESENTATION: This case report highlights the utility of mitral annular systolic velocity (S') by tissue Doppler imaging and peak LV outflow tract (LVOT) velocity as markers of LV intrinsic contractile function during DSE in a patient with low flow low gradient AS and reduced EF prior to transcatheter aortic valve implantation (TAVI). CONCLUSIONS: Mitral annular S' and peak LVOT velocities are reliable markers of LV intrinsic contractile function and should be incorporated into routine low-dose DSE.

Regional myocardial strain analysis via 2D speckle tracking echocardiography: validation with sonomicrometry and correlation with regional blood flow in the presence of graded coronary stenoses and dobutamine stress.

BACKGROUND: Quantitative regional strain analysis by speckle tracking echocardiography (STE) may be particularly useful in the assessment of myocardial ischemia and viability, although reliable measurement of regional strain remains challenging, especially in the circumferential and radial directions. We present an acute canine model that integrates a complex sonomicrometer array with microsphere blood flow measurements to evaluate regional myocardial strain and flow in the setting of graded coronary stenoses and dobutamine stress. We apply this unique model to rigorously evaluate a commercial 2D STE software package and explore fundamental regional myocardial flow-function relationships. METHODS: Sonomicrometers (16 crystals) were implanted in epicardial and endocardial pairs across the anterior myocardium of anesthetized open chest dogs (n = 7) to form three adjacent cubes representing the ischemic, border, and remote regions, as defined by their relative locations to a hydraulic occluder on the mid-left anterior descending coronary artery (LAD). Additional cardiac (n = 3) and extra-cardiac (n = 3) reference crystals were placed to define the cardiac axes and aid image registration. 2D short axis echocardiograms, sonometric data, and microsphere blood flow data were acquired at baseline and in the presence of mild and moderate LAD stenoses, both before and during low-dose dobutamine stress (5 µg/kg/min). Regional end-systolic 2D STE radial and circumferential strains were calculated with commercial software (EchoInsight) and compared to those determined by sonomicrometry and to microsphere blood flow measurements. Post-systolic indices (PSIs) were also calculated for radial and circumferential strains. RESULTS: Low-dose dobutamine augmented both strain and flow in the presence of mild and moderate stenoses. Regional 2D STE strains correlated moderately with strains assessed by sonomicrometry (Rradial = 0.56, p < 0.0001; Rcirc = 0.55, p < 0.0001) and with regional flow quantities (Rradial = 0.61, Rcirc = 0.63). Overall, correspondence between 2D STE and sonomicrometry was better in the circumferential direction (Bias ± 1.96 SD: - 1.0 ± 8.2% strain, p = 0.06) than the radial direction (5.7 ± 18.3%, p < 0.0001). Mean PSI values were greatest in low flow conditions and normalized with low-dose dobutamine. CONCLUSIONS: 2D STE identifies changes in regional end-systolic circumferential and radial strain produced by mild and moderate coronary stenoses and low-dose dobutamine stress. Regional 2D STE end-systolic strain measurements correlate modestly with regional sonomicrometer strain and microsphere flow measurements.

Role of strain imaging for assessment of myocardial viability in symptomatic myocardial infarction with single vessel disease: An observational study.

PURPOSE: To study and evaluate the predictive value of strain imaging parameters in patients undergoing viability assessment postmyocardial infarction (MI) in comparison with Dobutamine stress echocardiography (DSE) alone. METHODS: This was a prospective observational study (October, 2016-March, 2018), which recruited 100 symptomatic patients with MI, and angiographically proven single vessel disease, LV dysfunction with severe hypokinesia/akinesia on 2D echocardiography and viability proven by baseline DSE. Patients undergoing primary PCI were excluded. Patients were recruited in two groups: DSE alone (first group) and strain imaging with DSE (second group). Revascularization was done in all patients. Patients were assessed at 3 months for functional recovery by 2D echocardiography. RESULTS: On 3 month follow-up after revascularization, 37 patients (74%) in first group and 33 patients (66.67%) in second group had functional recovery. Dobutamine-stimulated strain parameters such as circumferential strain (CS; P = .005), radial velocity (RV; P < .001), longitudinal strain (LS; P < .001), and longitudinal strain rate (LSR; P < .001) were found to be a significant predictor of viability. The greatest area under the curve (AUC) for the ROC curves was obtained for low dose dobutamine RV (AUC = 0.92), low dose dobutamine LS (AUC = 0.94), and low dose dobutamine LSR (AUC = 0.88). Positive predictive value of the combination of low dose DSE with strain parameters (RV-97.2%, LS-97.4%, and LSR-87.5%) for myocardial viability was significantly higher than low dose DSE positive/low dose strain parameters negative patients as well as low dose DSE group alone. CONCLUSION: Evaluation of strain parameters with low dose DSE is clinically feasible for the detection of myocardial viability and adds incremental value to the subjective and semiquantitative wall-motion scoring. LS at low dose DSE with WMSI was found to have the highest positive predictive value.

Additional diagnostic accuracy of global longitudinal strain at peak dobutamine stress in patients with moderate pretest probability of coronary artery disease.

BACKGROUND: Previous studies confirmed the feasibility of 2D speckle tracking echocardiography (2D STE) during dobutamine stress echocardiography (DSE) in assessing myocardial ischemia in patients with previous myocardial infarction. It is unknown whether it improves the diagnostic accuracy in young patients with intermediate pretest probability for coronary artery disease (CAD) and no prior cardiovascular events. METHODS: We prospectively studied 101 patients by DSE and STE, followed by coronary angiography within 1 month. Significant CAD was defined as diameter stenosis ≥ 50%. Receiver operating characteristic analysis obtained global longitudinal strain (GLS) cutoff values of significant area under the curve (AUC). RESULTS: Mean age: 53 ± 8 years, 56% females, 49 had significant CAD (group 1) and 52 had normal/mild CAD (group 2); no significant baseline differences except more males in group 1 (P: .002). DSE sensitivity and specificity for CAD were 79.6% and 92.3%, respectively, positive predictive value (PPV): 90.6%, negative predictive value (NPV): 82.7%, and diagnostic accuracy: 86%. At peak stress, all strain parameters were significantly lower in group 1. However, GLS had the highest AUC: 0.88, P: <.001. GLS cutoff value ≤ -20.5 had 89.8% sensitivity, 84.6% specificity, 84.6% PPV, 89.8% NPV, and 87% diagnostic accuracy. Combining GLS cutoff with DSE had higher AUC than either alone (0.9, P < .001): 95.9% sensitivity, 84.6% specificity, 85.5% PPV, 95.7% NPV, and 90% diagnostic accuracy. CONCLUSION: 2D-STE-derived GLS increases DSE precision to detect CAD in intermediate pretest probability patients: It improves DSE sensitivity, NPV, and accuracy. It is reproducible and has comparable specificity.