Dobutamine Stress Echocardiography Research Articles

Abstract 4115015: Hyperpolarized Carbon-13 Metabolic Imaging Detects Changes in Cardiac Mitochondrial Metabolism in Patients Before and After Coronary Artery Bypass Graft Surgery

Background: Coronary Artery Disease (CAD) is a significant global health issue, necessitating improved diagnostic tools for visualizing cardiac energetics. Traditional imaging methods such as PET and dobutamine stress echocardiography do not directly assess mitochondrial metabolism. Hyperpolarized Carbon-13 metabolic magnetic resonance imaging (HP- 13 C MRI) offers a promising non-invasive method for investigating mitochondrial function in CAD. This study utilizes HP- 13 C MRI to detect changes in mitochondrial metabolism in patients undergoing Coronary Artery Bypass Graft (CABG) surgery (Fig.1). Methods: We conducted HP- 13 C MRI examinations on two patients with advanced CAD before and (~4-6 months after CABG surgery and one healthy subject (Fig. 2 A,B). Participating subjects provided informed consent according to a protocol approved by the Institutional Review Board and Protocol Review Committee. Baseline blood samples were analyzed for pyruvate, triglycerides, free fatty acids, and insulin levels. Post-glucose load, patients received an intravenous injection of an IND-approved metabolic probe, [1- 13 C] pyruvic acid, prepared under Good Manufacturing Practice regulations. The HP solution was administered after polarization in a clinical polarizer (SPINlab™, GE Healthcare). Imaging was performed using a GE MR750 MR system with a Helmholtz loop-pair 13 C coil (PulseTeq Limited, UK). Data were reconstructed and analyzed with MATLAB scripts. Results and Discussion: Baseline blood measurements were normal for the healthy subject, but those with advanced CAD showed variable and abnormal values (Fig. 2C). HP- 13 C MRI safely assessed cardiac metabolism in patients with advanced CAD. Patients with advanced CAD exhibited reduced pyruvate metabolism compared to healthy controls, shown by lower myocardial bicarbonate/(bicarbonate+lactate) ratios (Bic/(Bic+Lac)). Following CABG, only Patient 2 showed improved Bic/(Bic+Lac), while Patient 1 did not (Fig. 3A-B). This variability may be influenced by differences in nutrition, hormonal status, medication regimens, or other factors. Changes in % Bic/(Bic+Lac) across different coronary artery segments were observed post-CABG in CAD patients (Fig. 3C). Conclusion: HP- 13 C MRI non-invasively assesses cardiac metabolism in CAD patients, demonstrating the potential to evaluate post-CABG metabolic changes. Our efforts continue to recruit large cohort to understand individual variability.

Double product derived from exercise stress echocardiography (ESE) or dobutamine stress echocardiography (DSE) in patients with a history of breast cancer and radiotherapy (RXT) exposure and MACE

Abstract Background Breast cancer survivorship has markedly improved in the last two decades due to improved therapies. Among these, adjuvant chest radiotherapy stands out as an integral part of the current treatment. Chest radiotherapy can trigger accelerated atherosclerosis, which, coupled with cardiovascular (CV) risk factors common to this population, can lead to increased rates of coronary artery disease (CAD). ESC 2022 guidelines have established both Exercise Stress Echocardiography (ESE) and Dobutamine Stress Echocardiography (DSE) as cost-efficient and reliable tools for screening this patient population. Recommendations include ESE or DSE 5 years after radiotherapy as a screening tool. Double product (DP), an index common to both tests, parallels myocardial oxygen consumption. It has been used to predict major adverse cardiovascular events (MACE) in other cohorts. Purpose We sought to evaluate if DP could be used as a prognostic indicator for MACE (myocardial infarction, stroke, cardiovascular death, and heart failure) in this population. Methods Breast cancer patients treated with adjuvant radiotherapy from 2000 to 2022 were included. ESE or DSE was done after a mean of 5.4 years (1Q-2.2, 3Q-7.5) post-radiotherapy. Uni and multivariable adjusted Cox regression models were performed to evaluate the association between DP quartiles achieved and the risk of MACE in DSE and ESE groups. MACE-free survival among different quartiles was plotted with the Kaplan Meier method. Results 696 patients were included, with a mean age of 65 (SD 10.0) and 72 (SD 9.4) in ESE and DSE respectively. 61% of patients had ESE. In ESE, we observed increased rates of MACE in the 1st quartile when compared to the other quartiles (Figure 1a). On the other hand, univariate and multivariate Cox models established that for every increase of 1000 units of DP achieved during ESE, there is a risk-reduction of 9% [HR=0.91 (0.86-0.95); p=<0.01] in the future incidence of MACE, thus establishing DP as a protective marker. Additionally, advanced age was shown to be a major risk factor as well [HR=4.58 (1.91-10.9); p=<0.01]. In the DSE cohort however, the development of MACE was equally distributed across DP quartiles even after adjusting for existing comorbidities (Figure 1b). Cox analysis did not establish DP as a prognostic tool in this cohort (Table 1). Conclusion DP is established as an excellent prognostic tool for the detection of MACE in patients who underwent ESE. Patients who achieve higher DP quartiles during these tests have lower future rates of MACE. Regarding DSE, DP is not a good prognostic tool. This could be explained by higher burden of cardiovascular risk factors in this patient population. ESE should be recommended when possible.

Time to target heart rate in dobutamine stress echocardiography is shortened by using dynamic, but not isometric handgrip

Abstract Background Dobutamine stress echocardiography (DSE) is widely used for the detection of obstructive ischaemic heart disease. In our previous study we demonstrated that the magnitude of myocardial injury measured by hsTnT is associated with DSE duration. Shortening of DSE time is therefore desirable. Use of hangrip (HG) during DSE is generally recommended. However, there are no published studies comparing the efect of dynamic and isometric HG on the length of DSE. Purpose To compare the effect of dynamic and static HG on DSE duration. Methods 211 patients undergoing DSE for ischaemia assessment were randomised into no HG (noHG, n=74), isometric HG (isoHG, n=68) and gynamic HG (dynHG, n=69) groups. All patients taking rate limiting medication were instructed to stop it 48 hours prior the test. DSE was performed according to the standard protocol (dobutamine infusion 5, 10, 20, 30, 40 ug/kg/min., increased in 3 min. intervals). HG was applied at the level of 40% maximum isometric muscular effort from the dobutamine dose of 20ug/kg/min. and atropine was administered in 1 min. intervals in 100 ug increments from the dose of 30 ug/kg/min. Patients who did not achieve their target heart rate (HR) or suffered from dobutamine side effects were excluded from the study. Results There were no differences in the groups characteristics (gender p=0.187, known ischaemic heart disease p=0.361, age p=0.128, basal HR p=0.367, target HR p=0.107, achieved HR p=0.257, positive test for ischaemia p=0.583). There was a significant difference in the time to target HR between dynHG and noHG groups (9.97±2.34 vs 11.96±3.02 min., p< 0.001) but not between isoHG and noHG groups (10.76±3.12 vs 11.96±3.02 min., p=0.058). Also, the was a similar difference in the length of dobutamine infusion between dynHG and noHG, but not between isoHG and noHG groups (11.76±2.37 vs 13.78±3.09 min., p< 0.001 and 13.34±4.90 vs 13.78±3.09 min., p=0.308, respectively). No significant correlation was found between the time to target HR and basal (r=0.43) or target HR (r=0.38). Conclusion Dynamic, but not isometric handgrip shortens the length of dobutamine stress echocardiography.

Diagnostic value of low dose dobutamine stress echocardiography in paradoxical low flow low gradient aortic stenosis

Abstract Background In aortic stenosis with low-gradient scenarios distinguishing between fixed and pseudo-severe stenosis becomes challenging. Low-dose dobutamine stress echocardiography (DSE) is recommended for classical low-flow low- gradient stenosis with reduced ejection fraction. Doubts of DSE's utility in paradoxical low-flow low-gradient (PLFLG) stenosis when ejection fraction is preserved are partially reasoned by proposed inefficiency in generating a contractile reserve 1. Guidelines advocate an integrated approach, combining various clinical and imaging aspects 2. Purpose This study aimed to investigate usefulness of DSE in PLFLG stenosis, identifying specific features to predict the possibility of generating significant stroke volume augmentation and distinguishing fixed aortic stenosis. Methods We identified patients with aortic stenosis who underwent DSE and multi-modality imaging at our centre between 2020 and 2023. Among them, those with PLFLG situations were used for detailed analysis. Multiple linear regression analysis was performed to identify parameters predictive of significant contractile reserve, defined as 20% stroke volume increase from baseline. For patients demonstrating contractile reserve we assessed predefined parameters by receiver operating characteristics (ROC) analysis to predict fixed stenosis defined as final aortic valve area < 1cm² and valve area change <0.2cm² or final mean pressure gradient >40mmHg. For predictive value of Agatston score we conducted post-hoc analysis. Results Among 256 DSE cases, 67 were conducted for PLFLG stenosis. Patients were 82 years of median age and mostly female (63%). Symptoms included dyspnea in 90% and angina in 40% of cases. Baseline echo showed median aortic valve area (indexed to body surface area) of 0.8cm² (0.44cm²/m²) with mean pressure gradient of 20mmHg. Contractile reserve was inducible in 70% of patients, of which 74% showed criteria of fixed stenosis. Higher left ventricular end-diastolic diameter (LVESD) and lower baseline systolic flow-rate were predictive for contractile reserve (p<0.05). Among patients with contractile reserve ROC for baseline mean pressure gradient, acceleration time (median 0.08s; range 0.04-0.11s) and acceleration time to ejection time index (0.28; range: 0.148-0.458) revealed good prediction of fixed stenosis in DSE meanwhile Agatston calcium score (median 1076; range: 301-8821) did not (figure 1). No correlation was found between Agatston score probability of severe stenosis and aortic valve pressure gradient behavior with increased stroke volume (figure 2). Conclusion DSE proves to be a useful a method in the differentiation between fixed and pseudo-severe stenosis in PLFLG situation. Our findings question the predictive value of Agatston score for aortic valve behavior with increase of stroke volume and warrant further investigations regarding value of acceleration time and acceleration time to ejection time index in those patients.Receiver operating characteristicsPost-hoc analysis of Agatston score

The prognostic value of contrast stress echocardiography in a real-world population of symptomatic patients without known coronary artery disease

Abstract Background Coronary artery disease (CAD) is the leading cause of mortality and morbidity worldwide. In addition to diagnosis, non-invasive tests may also provide prognostic information useful in the risk stratification and management of CAD patients. Stress echocardiography (SE) is an accurate, non-invasive method for the detection of obstructive CAD. However, in real-world clinical practice the test performance may vary among different centres, depending on availability, local protocols, and operator expertise. Purpose To evaluate the prognostic value of contrast SE in a real-world population of symptomatic patients without known CAD. Methods This was a cohort follow-up study of patients without known CAD and symptoms of atypical chest pain, unexplained dyspnoea or palpitations who were referred to the echocardiography lab of a tertiary hospital for SE between January 2020 and December 2021. Patients with resting regional wall motion abnormalities were excluded. All patients underwent treadmill exercise stress echocardiography (ESE) or dobutamine stress echocardiography (DSE) if unable to exercise. Contrast agents were used in almost all patients (99%). The study population was followed-up for at least 2 years after SE by phone and/or electronic hospital records. Cardiac outcome was defined as anatomically or functionally significant stenosis on angiography, revascularization, acute coronary syndrome (ACS), or cardiac-related death. Results The study comprised 266 patients (mean age 58±12 years, 63% male) who underwent either ESE (58%) or DSE (42%). The patients' details are reported in Table 1. The most common indication for the exam was atypical chest pain, with a prevalence of 73%. SE exams were positive for inducible ischaemia in 14 (5%) patients. Symptoms during the exam were present in 3 (21%) patients with positive SE and 4 patients (2%) with negative SE (p=0.004). No serious complications (sustained ventricular tachycardia, myocardial infarction, or death) were recorded. During the follow-up (median 30, IQR 23–38 months), 264 patients (99%) were successfully contacted. Cardiac outcome occurred in 10 patients. Among 14 patients with positive SE, 8 underwent revascularization due to significant coronary artery stenosis. Among 250 patients with negative SE, 1 underwent revascularization due to significant coronary artery stenosis and 1 presented with ACS 13 months after the test (both patients underwent DSE). Negative predictive value was 99% over a median follow-up of 30 months, corresponding to an annualized event rate of 0.32% per year. A positive SE was significantly associated with cardiac outcome (log-rank test p<0.0001, Figure 1). Conclusion Contrast SE carries significant prognostic implications in symptomatic patients without known CAD. A positive test is strongly associated with the need for revascularization, while a normal test result has an excellent negative predictive value regarding cardiovascular morbidity and mortality.Figure 1

Functional correlates of ischemic electrocardiographic changes during stress echocardiography. data form stress echo 2030 survey

Abstract Background/Introduction Cardiac stress tests are carried out in populations with a low probability of ischemic heart disease (IHD) much more frequently than in the past. Stress ECG remains a frequently used modality for the diagnosis of IHD in vast areas of the world with limited facilities. Purpose To assess the diagnostic value of stress ECG for diagnosing IHD using inducible regional wall motion abnormalities (RWMA) on stress echocardiography (SE) as the gold standard method of diagnosis. Methods The 12-lead ECG response was retrospectively analyzed in 4317 patients (age 64±13 years, 59.6% males) undergoing SE for chronic coronary syndromes who were prospectively recruited from 39 cardiac centers between March 2021 and February 2024. Exclusion criteria were left bundle branch block or pacemaker rhythm. ECG response was considered ischemic according to standard criteria (if ST-segment deviated >1.0 mm from baseline in ≥2 contiguous leads at 80 ms from J point) during an exercise (n=2980, 69.8%), dobutamine (n = 766, 18.0%), or vasodilator (n=519, 12.2%) SE. All patients underwent a comprehensive SE protocol with an assessment of wall motion score index (WMSI), B-lines (4-site simplified score), left ventricular contractile reserve (LVCR) based on force, coronary flow velocity reserve (CFVR) in the mid-distal left anterior descending artery (LAD), and heart rate reserve (HRR). Results ECG changes occurred in 641 patients (14.8%, Group 1) for the overall studied population. Compared to patients without ECG changes (Group 2, n=3676, 85.2%), patients with ECG changes showed higher values of peak WMSI and lower values of CFVR and LVCR (see table).Amongst patients without inducible RWMA (n=3553), there were 392 (11%) patients with an ischemic ECG at stress (89% specificity). Of 764 patients with inducible RWMA during SE, 249 had an ischemic ECG trace (sensitivity 33%). In patients without inducible RWMA, those with ischemic ECG changes showed similar abnormal stress B-lines (23% vs. 21%, p=0.719), LVCR (61% vs. 63%, p=0.602), CFVR (31% vs 33%, p=0.607) and HRR (37% vs 41%, p=0.097) compared to those without ECG changes. Amongst patients with inducible RWMA and ECG changes, CFVR was significantly lower in patients with ECG changes (39.2% and 60.8%, respectively, p<0.001). Conclusions Simple standard stress ECG diagnostic value in the current era in populations with a low probability of IHD seems to be low. However, during SE, stress-induced ischemic ECG changes are associated with more extensive RWMA and blunted global LVCR, with reduced CFVR in the LAD. Therefore, analysis of ST segment changes during stress imaging studies can offer additional, significant information.

Dobutamine-induced transient cardiomyopathy during dobutamine stress echocardiography

Abstract: Takotsubo cardiomyopathy is a syndrome characterized by transient left ventricular (LV) dysfunction in the absence of significant coronary artery disease. We report a rare case of dobutamine-induced transient cardiomyopathy during dobutamine stress echocardiography, whose coronary angiography was suggestive of noncritical coronary artery disease. The patient was managed conservatively and was discharged after 7 days in a hemodynamically stable condition with improved LV function. Anticoagulation was not pursued due to improvement in LV function. We also herein aim to review the epidemiology, various accepted mechanisms of etiopathogenesis, clinical features, complications, diagnostic criteria, and currently practiced guidelines on the management of stress-induced cardiomyopathy.

ST Elevation during Dobutamine Stress Echocardiography: Important Diagnostic and Prognostic Marker

ST Elevation during Dobutamine Stress Echocardiography: Important Diagnostic and Prognostic Marker

Prognostic value of dobutamine stress echocardiography for the long-term outcomes in kidney transplant candidates.

Cardiovascular disease is a primary cause of morbidity and mortality in kidney transplant (KT) candidates. Dobutamine stress echocardiography (DSE) is an effective noninvasive modality for evaluating coronary artery disease with high accuracy. However, long-term data in KT candidates are still lacking. This study aims to assess the prognostic value of DSE in predicting long-term outcomes in KT candidates. This study retrospectively included consecutive KT candidates who underwent preoperative DSE between 2007 and 2017 at Siriraj Hospital, Bangkok, Thailand. Normal DSE was characterized by the absence of wall motion abnormalities both at rest and during stress. The primary endpoint was all-cause mortality. Univariable and multivariable analyses were conducted to determine predictors of all-cause mortality, with a P value of <0.05 considered statistically significant. Among 269 patients (mean age 51 years, 58% male), 34 (12.6%) had abnormal DSE results, and 63 (23%) underwent kidney transplantation after DSE. During a median follow-up period of 7.6 (4.5, 10.1) years, 129 (48%) patients died. Patients with abnormal DSE had a significantly higher mortality rate than those with normal DSE (73.5% vs. 44.2%, P=0.003). Univariable analysis demonstrated that male gender [hazard ratio (HR) 1.50, 95% confidence interval (CI): 1.04-2.16, P=0.03], resting systolic blood pressure (HR 1.006, 95% CI: 1.00-1.01, P=0.04), abnormal DSE (HR 1.95, 95% CI: 1.25-3.05, P=0.003), higher delta wall motion score index (HR 2.57, 95% CI: 1.24-5.35, P=0.01), abnormal stress left ventricular end-systolic volume (HR 2.05, 95% CI: 1.11-3.82, P=0.02), and post-KT status (HR 0.48, 95% CI: 0.30-0.79, P=0.004) were associated with mortality. In the multivariable analysis, male gender and abnormal DSE were independent predictors of mortality [adjusted HR (aHR) 1.65, 95% CI: 1.06-2.20, P=0.02 and aHR 1.88, 95% CI: 1.20-2.93, P=0.006, respectively], while post-KT status emerged as an independent predictor of better outcomes (aHR 0.47, 95% CI: 0.29-0.77, P=0.003). In KT candidates, preoperative assessment with DSE provides valuable prognostic information for long-term outcomes, particularly regarding all-cause mortality.

Randomised study for the Optimal Treatment of symptomatic patients with low-gradient severe Aortic valve Stenosis and preserved left ventricular ejection fraction (ROTAS trial)

BackgroundThe best management of symptomatic patients with low-gradient (LG) severe aortic stenosis (AS) and preserved left ventricular ejection fraction (LVEF) has not been established. The Randomised study for the Optimal...

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

AbstractObjectiveWe 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.MethodsWe conducted MCE and DSE tests on 53 coronary heart disease patients, categorizing ischemic myocardium into four groups: A (&lt;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 β, and the product A × β, reflecting different aspects of myocardial blood flow.ResultsParametric values of myocardial perfusion (PVMPs) were significantly lower in group D at rest compared with other groups (p &lt; 0.001). PVMPs increased notably at peak dobutamine stress in groups A, B, and C (p &lt; 0.001). Groups A and B had higher PVMPs than groups C and D, with group D significantly lower (p &lt; 0.001). β reserve values decreased gradually from group A to D, with significantly lower values of A and A × β in groups C and D compared with A and B (p &lt; 0.001). Sensitivity and specificity for predicting &gt;70% coronary artery blockage was 80%, 66%, and 74%, 80%, respectively, using specific thresholds.ConclusionCombining 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.

Right parasternal view in dobutamine stress echocardiography for aortic stenosis assessment.

Dobutamine stress echocardiography is an integral part of the evaluation of aortic stenosis (AS) severity in low-gradient AS. In transthoracic echocardiography, in 20% of the patients, the highest aortic valve peak transvalvular velocity and mean gradient are achieved with continuous wave Doppler, from the suprasternal or right parasternal view. We present a case of a 79-year-old-male, with low-gradient aortic stenosis, where the highest peak aortic valve velocity and mean gradient, were consistently obtained from the right parasternal view, during all stages of a dobutamine stress echocardiogram. Use of the right parasternal view was important in avoiding overestimation of aortic valve area and underestimation of aortic valve mean gradients and therefore AS severity at rest. Furthermore, it correctly identified significant increase of aortic valve mean gradients during stress and therefore confirmed the diagnosis of severe AS. This case report highlights the importance of routinely attempting right parasternal view, in patients undergoing stress echocardiography to ensure the maximum possible aortic valve gradient is obtained.

The effects of myocardial bridging on two-dimensional myocardial strain during dobutamine stress echocardiography.

Myocardial bridging (MB) is a common anatomic variant in coronary arteries with unclear functional significance. We evaluated regional myocardial strain by speckle tracking during dobutamine stress echocardiography (DSE) in patients with MB in the left anterior descending coronary artery (LAD). We studied 11 patients with MB in the LAD and no obstructive coronary artery disease (CAD), 7 patients without MB, but obstructive CAD in the LAD, and 12 controls without MB or obstructive CAD. MB was defined as either > 1mm (superficial) or > 2mm (deep) intramyocardial course of the LAD in coronary CT angiography. Regional longitudinal, radial and circumferential strains and strain rates as well as post-systolic strain index (PSI) were measured at rest, peak stress, and early recovery (1min after stress). Strain parameters during DSE were similar in the myocardium distal to MB and other myocardial regions of the same patients as well as the LAD territory in controls. However, patients with obstructive CAD showed impaired LS and strain rate as well as increased PSI at peak stress. None of the MB was associated with systolic compression in invasive coronary angiography and strain parameters were similar between superficial and deep MB. Stress myocardial blood flow by positron emission tomography correlated with LS and RS at peak stress in the myocardium distal to MB (r = -0.73, p = 0.03, and r = 0.64, p = 0.04, respectively). Myocardial strain is not reduced during DSE in patients with MB in the LAD and no significant systolic compression.

Dobutamine stress echocardiography after positive CCTA: diagnostic performance using fractional flow reserve and instantaneous wave-free ratio as reference standards

AimsTo assess the diagnostic accuracy of dobutamine stress echocardiography (DSE) in symptomatic patients with a low to intermediate pretest probability of obstructive coronary artery disease (CAD) and a positive coronary...

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

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. 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). 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±.27cm 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. 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.

Acute ST elevation myocardial infarction (STEMI) in a patient with leptospirosis; a therapeutical dilemma – A case report

A 45-year-old previously healthy farmer was seen at the Emergency Department with ischemic type chest pain. He had a history of an acute febrile illness for four days. The ECG showed an acute anterior myocardial infarction. His laboratory investigations revealed thrombocytopenia, a raised serum creatinine level and significantly raised high-sensitive cardiac Troponin I. A provisional diagnosis of acute STEMI with co-existing leptospirosis was made. The patient was managed conservatively with antibiotics, statins, and aspirin. Neither thrombolysis nor primary coronary intervention was attempted due to high risk of bleeding. Diagnosis of leptospirosis was confirmed later by markedly elevated leptospira antibodies. After recovery, he underwent coronary angiogram which revealed a totally occluded left anterior descending artery and is awaiting myocardial viability assessment with dobutamine stress echocardiography before PCI. We report this uncommon presentation of acute myocardial infarction in a patient with leptospirosis, as it causes a considerable therapeutic dilemma especially in a resource-poor setting.

Dobutamine Stress Echocardiography in Low-Gradient Aortic Stenosis

Guidelines recommend the use of dobutamine stress echocardiography (DSE) in patients with low-gradient aortic stenosis (AS) and left ventricular ejection fraction (LVEF)<50%. However, a paucity of DSE data exists when LVEF >35%. To examine the diagnostic accuracy of DSE in patients with low-gradient AS with a wide range of LVEF and to examine the interaction between the diagnostic accuracy of DSE and LVEF. Patients with mean gradient <40mm Hg, aortic valve area <1.0cm2, and stroke volume index ≤35mL/m2 undergoing DSE and cardiac computer tomography (C-CT) were identified from 3 prospectively collected patient cohorts and stratified according to LVEF: LVEF<35%, LVEF 35% to 50%, and LVEF>50%. Dobutamine stress echocardiography and C-CT were performed on patients with low-gradient AS. Severe AS was defined as aortic valve calcification score ≥2,000 arbitrary units (AU) among men and ≥1,200 AU for women on C-CT. Of 221 patients included in the study, 78 (35%) presented with LVEF <35%, 67 (30%) with LVEF 35% to 50%, and 76 (34%) with LVEF >50%. Mean-gradient and aortic valve peak velocity during DSE showed significant diagnostic heterogeneity between LVEF groups, being most precise when LVEF <35% (both areas under the curve [AUC]=0.90), albeit with optimal thresholds of 30mm Hg and 377cm/sec and a limited diagnostic yield in patients with LVEF ≥35% (AUC=0.67 and 0.66 in LVEF 35% to 50% and AUC=0.65 and 0.60 in LVEF ≥50%). Using guideline thresholds led to a sensitivity/specificity of 49%/84% for all patients with LVEF <50%. While DSE is safe and leads to an increase in stroke volume in patients with low-gradient AS regardless of LVEF, the association between DSE gradients and AS severity assessed by C-CT demonstrates important heterogeneity depending on LVEF, with the highest accuracy in patients with LVEF <35%.

Assessment of Myocardial Viability in Ischemic Cardiomyopathy With Reduced Left Ventricular Function Undergoing Coronary Artery Bypass Grafting.

We aim to provide a comprehensive review of the current state of knowledge of myocardial viability assessment in patients undergoing coronary artery bypass grafting (CABG), with a focus on the clinical markers of viability for each imaging modality. We also compare mortality between patients with viable myocardium and those without viability who undergo CABG. A systematic database search with meta-analysis was conducted of comparative original articles (both observations and randomized controlled studies) of patients undergoing CABG with either viable or nonviable myocardium, in EMBASE, MEDLINE, Cochrane database, and Google Scholar, from inception to 2022. Imaging modalities included were dobutamine stress echocardiography (DSE), cardiac magnetic resonance (CMR), single-photon emission computed tomography (SPECT), and positron emission tomography (PET). A total of 17 studies incorporating a total of 2317 patients were included. Across all imaging modalities, the relative risk of death post-CABG was reduced in patients with versus without viability (random-effects model: odds ratio: 0.42; 95% confidence interval: 0.29-0.61; p < 0.001). Imaging for myocardial viability has significant clinical implications as it can affect the accuracy of the diagnosis, guide treatment decisions, and predict patient outcomes. Generally, based on local availability and expertise, either SPECT or DSE should be considered as the first step in evaluating viability, while PET or CMR would provide further evaluation of transmurality, perfusion metabolism, and extent of scar tissue. The assessment of myocardial viability is an essential component of preoperative evaluation in patients with ischemic heart disease undergoing surgical revascularization. Careful patient selection and individualized assessment of viability remainparamount.

Prognostic Impact of High-Molecular-Weight von Willebrand Factor Multimer Ratio in Classical Low-Flow Low-Gradient Aortic Stenosis.

High-molecular-weight (HMW) von Willebrand factor (VWF) multimer deficiency occurs in classical low-flow, low-gradient (LF/LG) aortic stenosis (AS) due to shear force-induced proteolysis. The prognostic value of HMW VWF multimer deficiency is unknown. Therefore, we sought to evaluate the impact of HMW VWF multimer deficiency on clinical outcome. In this prospective research study, a total of 83 patients with classical LF/LG AS were included. All patients underwent dobutamine stress echocardiography to distinguish true-severe (TS) from pseudo-severe (PS) classical LF/LG AS. HMW VWF multimer ratio was calculated using densitometric Western blot band quantification. The primary endpoint was all-cause mortality. Mean age was 79 ± 9 years, and TS classical LF/LG AS was diagnosed in 73% (n = 61) and PS classical LF/LG AS in 27% (n = 22) of all patients. Forty-six patients underwent aortic valve replacement (AVR) and 37 were treated conservatively. During a mean follow-up of 27 ± 17 months, 47 deaths occurred. Major bleeding complications after AVR (10/46; 22%) were more common in patients with HMW VWF multimer ratio &lt;1 (8/17; 47%) in comparison to patients with a normal multimer pattern (2/29; 7%) at baseline (p = 0.003). In a multivariable Cox regression analysis, HMW VWF multimer deficiency was a predictor of all-cause mortality (HR: 3.02 [95% CI: 1.31-6.96], p = 0.009) in the entire cohort. This association was driven by higher mortality rates in the AVR group (multivariable-adjusted HR: 9.4; 95% CI 2.0-43.4, p = 0.004). This is the first study to demonstrate the predictive value of HMW VWF multimer ratio for risk stratification in patients with classical LF/LG AS. HMW VWF multimer deficiency was associated with an increased risk of all-cause mortality and major bleeding complications after AVR.

Impact of Stress Echocardiography on Aortic Valve Stenosis Management.

Rest and stress echocardiography (SE) play a fundamental role in the evaluation of aortic valve stenosis (AS). According to the current guidelines for the echocardiographic evaluation of patients with aortic stenosis, four broad categories can be defined: high-gradient AS (mean gradient ≥ 40 mmHg, peak velocity ≥ 4 m/s, aortic valve area (AVA) ≤ 1 cm2 or indexed AVA ≤ 0.6 cm2/m2); low-flow, low-gradient AS with reduced ejection fraction (mean gradient < 40 mmHg, AVA ≤ 1 cm2, left ventricle ejection fraction (LVEF) < 50%, stroke volume index (Svi) ≤ 35 mL/m2); low-flow, low-gradient AS with preserved ejection fraction (mean gradient < 40 mmHg, AVA ≤ 1 cm2, LVEF ≥ 50%, SVi ≤ 35 mL/m2); and normal-flow, low-gradient AS with preserved ejection fraction (mean gradient < 40 mmHg, AVA ≤ 1 cm2, indexed AVA ≤ 0.6 cm2/m2, LVEF ≥ 50%, SVi > 35 mL/m2). Aortic valve replacement (AVR) is indicated with the onset of symptoms development or LVEF reduction. However, there is often mismatch between resting transthoracic echocardiography findings and patient's symptoms. In these discordant cases, SE and CT calcium scoring are among the indicated methods to guide the management decision making. Additionally, due to the increasing evidence that in asymptomatic severe aortic stenosis an early AVR instead of conservative treatment is associated with better outcomes, SE can help identify those that would benefit from an early AVR by revealing markers of poor prognosis. Low-flow, low-gradient AS represents a challenge both in diagnosis and in therapeutic management. Low-dose dobutamine SE is the recommended method to distinguish true-severe from pseudo-severe stenosis and assess the existence of flow (contractile) reserve to appropriately guide the need for intervention in these patients.