Dobutamine Test Research Articles

Prevalence of Coronary Microvascular Dysfunction and Epicardial Spasm in Patients With Angina and Myocardial Bridge

BackgroundMyocardial bridges (MB) are prevalent but not universally associated with angina. The mechanisms linking MB and angina are poorly defined. The objective of this study was to determine the prevalence of epicardial spasm, microvascular spasm, and/or endothelium-independent coronary microvascular dysfunction (CMD) in patients with MB which might explain symptoms. MethodsPatients with known MB and chest pain at the University of Chicago Medical Center between 2020-2023 were included. All patients underwent dobutamine testing with measurement of resting full-cycle ratio to determine hemodynamic significance (resting full-cycle ratio ≤0.76). Endothelium-independent CMD was defined as coronary flow reserve <2.0 or index of microvascular resistance ≥25 on adenosine testing. Microvascular spasm was defined as chest pain and electrocardiogram changes with nonischemic fractional flow reserve with acetylcholine. Epicardial spasm was defined as dynamic stenosis of >90% of the epicardial vessel or ischemic fractional flow reserve (≤0.8) with acetylcholine. ResultsA total of 30 patients (mean age, 47 ± 10 years; 60% female) with MB were studied. Endothelium-independent CMD, microvascular spasm, and epicardial spasm occurred commonly in 60%, 29%, and 37% of patients respectively, with 77% having at least one abnormality. The MB was hemodynamically significant in 47% of patients, and the prevalence of these coexisting conditions was not affected by hemodynamic significance. ConclusionsEpicardial spasm, microvascular spasm, and endothelium-independent CMD are prevalent in patients presenting with known MB and chest pain irrespective of the hemodynamic significance of the bridge. Invasive coronary function testing may play an important role in uncovering alternative explanations for angina in patients with known MB.

Myocardial injury in stress echocardiography: Comparison of dobutamine, dipyridamole and dynamic stressors-single center study.

In stress echocardiography (SE), dipyridamole (DIP) and dynamic stress (ExSE) are reported as being safer than dobutamine stress echocardiography (DSE). We investigated whether these commonly used stressors cause myocardial injury, measured by high sensitivity troponin T (hsTnT). One hundred and thirty five patients (DSE n = 46, ExsE n = 46, DIP n = 43) with negative result of SE were studied. The exclusion criteria were known ischaemic heart disease (IHD), baseline wall motion abnormalities, left ventricle systolic dysfunction/regional wall motion abnormalities, septum/posterior wall ≥13 mm, diabetes/pre-diabetes, baseline hsTnT level ≥14 ng/L, baseline blood pressure ≥160/100 mmHg, peak pulmonary pressure ≥45mmHg, eGFR <1ml/s/1.73m2 , more than mild to moderate valvular disease and dobutamine side effects. HsTnT was measured before and 180 minutes after the test. All patients had low pre-test probabilities of having obstructive IHD. HsTnT increased in DSE, less so in ExSE, and was unchanged in the DIP group (∆hsTnT 9.4 [1.5-58.6], 1.1 [-0.9-15.7], -0.1 [-1.4-2.1] ng/L, respectively, p<0.001). In DSE, the ∆hsTnT was associated with peak dobutamine dose (r = 0.30, p = 0.045), test length (r = 0.43, p = 0.003) and atropine use (p<0.001). In ExSE, the hsTnT increase was more likely in females (p = 0.012) and the elderly (>65 years) (r = 0.32, p = 0.03); no association was found between atropine use (p = 0.786) or test length and ∆hsTnT (r = 0.10, p = 0.530). DSE is associated with myocardial injury in patients with negative SE, no injury was observed in DIP and only mild case in ExSE. Whether myocardial injury is causative of the higher reported adverse event rates in DSE remains to be determined.

Identification of Silent Myocardial Ischemia in Patients with Long-Term Type 1 and Type 2 Diabetes

(1) Background: This study aimed to analyze epidemiological data to identify risk factors for silent myocardial ischemia in patients with long-term type 1 and type 2 diabetes. (2) Methods: An analysis was performed on 104 patients with long-term type 1 and type 2 diabetes who had not previously been diagnosed with cardiovascular disease. During hospitalization, patients were subjected to a standard ECG exercise test on a treadmill. If the test could not be performed or the result was uncertain, a pharmacological exercise test with dobutamine was performed. In the case of a positive exercise ECG test or a positive dobutamine test, the patient underwent coronary angiography. (3) Results: Atherosclerotic lesions were found in 24 patients. Patients with silent ischemia were significantly older and had a lower mean left ventricular ejection fraction and a higher incidence of carotid atherosclerosis. The presence of microvascular complications did not increase the risk of silent ischemia. (4) Conclusions: Silent heart ischemia is more common in type 2 than type 1 diabetes. Predisposing factors include older age, coexistence of carotid atherosclerosis, lower left ventricular ejection fraction, and smoking in patients with type 1 diabetes. Concomitant microvascular complications are not a risk factor.

Coronary Flow Velocity Reserve Using Dobutamine Test for Noninvasive Functional Assessment of Myocardial Bridging.

Background: It has been shown that coronary flow velocity reserve (CFVR) measurement by transthoracic Doppler echocardiography (TTDE) during dobutamine (DOB) provocation provides a more accurate functional evaluation of myocardial bridging (MB) compared to adenosine. However; the cut-off value of CFVR during DOB for identification of MB associated with myocardial ischemia has not been fully clarified. Purpose: This prospective study aimed to determine the cut-off value of TTDE-CFVR during DOB in patients with isolated-MB, as compared with stress-induced wall motion abnormalities (VMA) during exercise stress-echocardiography (SE) as reference. Methods: Eighty-one symptomatic patients (55 males [68%], mean age 56 ± 10 years; range: 27–74 years) with the existence of isolated-MB on the left anterior descending artery (LAD) and systolic MB-compression ≥50% diameter stenosis (DS) were eligible to participate in the study. Each patient underwent treadmill exercise-SE, invasive coronary angiography, and TTDE-CFVR measurements in the distal segment of LAD during DOB infusion (DOB: 10–40 μg/kg/min). Using quantitative coronary angiography, both minimal luminal diameter (MLD) and percent DS at MB-site at end-systole and end-diastole were determined. Results: Stress-induced myocardial ischemia with the occurrence of WMA was found in 23 patients (28%). CFVR during peak DOB was significantly lower in the SE-positive group compared with the SE-negative group (1.94 ± 0.16 vs. 2.78 ± 0.53; p < 0.001). ROC analyses identified the optimal CFVR cut-off value ≤ 2.1 obtained during high-dose dobutamine (>20 µg/kg/min) for the identification of MB associated with stress-induced WMA, with a sensitivity, specificity, positive and negative predictive value of 96%, 95%, 88%, and 98%, respectively (AUC 0.986; 95% CI: 0.967–1.000; p < 0.001). Multivariate logistic regression analysis revealed that MLD and percent DS, both at end-diastole, were the only independent predictors of ischemic CFVR values ≤2.1 (OR: 0.023; 95% CI: 0.001–0.534; p = 0.019; OR: 1.147; 95% CI: 1.042–1.263; p = 0.005; respectively). Conclusions: Noninvasive CFVR during dobutamine provocation appears to be an additional and important noninvasive tool to determine the functional severity of isolated-MB. A transthoracic CFVR cut-off ≤2.1 measured at a high-dobutamine dose may be adequate for detecting myocardial ischemia in patients with isolated-MB.

Random Forest Algorithm Construction for the Diagnosis of Coronary Heart Disease Based on Echocardiography Video Data Streams

Background. Recent studies show that cardiovascular diseases, including coronary heart disease, are the leading causes of death and one of the main factors of disability worldwide. The detection of cases of this type of disease over the past 30 years has increased from 271 million to 523 million and the number of deaths – from 12.1 million to 18.6 million. Cardiovascular diseases are the main cause of death among the population of Ukraine and, according to this indicator, the country remains one of the world leaders. Coronary heart disease is the leading factor in the loss of health in Ukraine and modern diagnostic methods, including machine learning algorithms, are increasingly being used for timely detection. Objective. According to the data of speckle-tracking echocardiography using the random forest method, construct classification algorithms for diagnosing violations of the kinematics of left ventricular contractions in patients with coronary heart disease at rest, and when using an echostress test with a dobutamine test. Methods. Speckle-tracking echocardiography was used to examine 40 patients with coronary heart disease and 16 in whom no cardiac pathology was found. Echocardiography was recorded in B mode in three positions: along the long axis, in 4-chamber, and 2-chamber positions. In total, 6245 frames of the video stream were used: 1871 – without cardiac abnormalities, and 4374 – in the presence of pathology during the examination. 56 patients (2509 frames of video data) were examined without the use of a dobutamine test and 38 patients (3736 frames of video data) – using an echostress test with a dobutamine test if no disturbances were found at rest. Dobutamine doses of 10, 20, and 40 mcg were administered under the supervision of an anesthesiologist. The data of texture analysis of images were used as informative features. To build an algorithm for detecting coronary heart disease the random forest algorithm was applied. Results. At the first stage of the study, the diagnostic algorithms norma–pathology for the state of rest and dobutamine doses of 10, 20, and 40 mcg were constructed. Before applying the algorithm the samples were randomly divided into training (70%) and test (30%). The classifiers were evaluated for accuracy, sensitivity, and specificity. According to the test samples, the accuracy of diagnostic conclusions varied from 97 to 99%. At the second stage of the study, to increase the versatility of the models, the classifier was built for all images, without dividing them into dobutamine doses. The accuracy for the test samples also ranged from 96.6 to 97.8%. To construct diagnostic algorithms by the random forest method the data of texture analysis of images were used. Conclusions. High-precision classification models were obtained using the random forest algorithm. The developed models can be applied to the analysis of echocardiograms obtained in B mode on equipment that is not equipped with the speckle tracking technology.

Exercise electrocardiography combined with stress echocardiography for predicting myocardial ischemia in adults.

Myocardial ischemia (MI) has the highest mortality rate in the world. Traditional noninvasive MI examinations include exercise electrocardiography tests (EETs) and stress echocardiography (SE). Treadmill and dobutamine tests are commonly used as stress protocols. In the present study, 278 patients with suspected MI were examined, 66 of whom were diagnosed with MI and 212 did not show evidence of MI by coronary angiography (CAG)/coronary CT angiography (CCTA). All patients underwent clinical EET and SE evaluations prior to CAG/CCTA. All groups were compared based on specific clinical parameters including age, sex, blood pressure, heart rate, blood oxygen saturation, underlying conditions and ejection fraction/fraction shortening. The data indicated superior diagnostic efficiency of the combined EET+SE method for the diagnosis of suspected MI compared with either EET or SE alone. The sensitivity/specificity/positive predictive value and negative predictive value for detecting MI were excellent compared with those of traditional examinations. The diagnostic efficiency of the combination analysis may reduce the prevalence of MI and medical costs. The present study provided novel insight for the development of methods that may be used for MI detection and prediction.

Evaluation of patients with myocardial infarction undergoing percutaneous coronary intervention (PCI) using low dose dobutamine stress echocardiography

Coronary artery disease (CAD) is a spectrum of heart diseases which has the highest mortality in the world. Systolic left ventricular (LV) function is an important predictor of outcome, and its precise assessment remains of great importance for the choice of treatment in populations with myocardial infarction (MI). This study was aimed to assess the function and viability of ischemic myocardium of LV before and after the percutaneous coronary intervention (PCI) by using 2dimentional (2D) STE with LDDSE and to know the usefulness of low dose dobutamine (LDD) test in detecting the viable ischemic LV area. The results of the current study revealed there was a significant decrease (improvement) in GLS before dobutamine from (-10.49±3.4) to (-12.87±3.44) after dobutamine. Then there was a significant increase (deterioration) in GLS from (-12.87±3.44) after giving 5 mg/kg/min dobutamine to (-11.56±3.29) after giving 10 mg/kg/min dobutamine (P value &lt; 0.001). While there were no significant differences in GLS after low dose dobutamine (-12.87±3.44) with the same parameters 3-6 months after PCI (-13.48±3.7). Left anterior descending artery (LAD) is the most common affected artery in our study. The study concluded that GLS provides a sensitive measure of LV function and appears reduced despite preserved LVEF also GLS can detect the viability of ischemic myocardium of LV with using LDD test which then assessed by PCI.

Stress echocardiography. Part I: Stress echocardiography in coronary heart disease.

Stress echocardiography (stress echo) is a method in which various stimuli are used to elicit myocardial contractility or provoke cardiac ischemia with simultaneous echocardiographic image acquisition of left ventricular function and valvular flow, if needed. The technique is a well-recognized, safe and widely available stress test used for the diagnosis and assessment of prognosis in coronary heart disease, but may also prove valuable in valvular heart disease. The stressors used include physical exercise, pharmacological agents (dobutamine, vasodilators) and pacing stress, most often with the use of a permanent pacemaker. Two operators should perform the test: a physician experienced in stress echocardiography (at least 100 tests completed under supervision of an expert) and a trained nurse or another doctor. The laboratory should feature a defibrillator and a resuscitation kit with a set of pharmaceuticals, an intubation kit and an AMBU bag. Pacing stress echo requires an external programmer for the implanted permanent pacemaker. Exercise should be the preferred stressor for the diagnosis of ischemic heart disease with alternative of high-dose dobutamine test in cases of contraindications to physical stress. Pacing stress echo is recommended for patients with pacemakers, and dipyridamole test for the assessment of coronary flow reserve. Chest pain in patients with intermediate probability of coronary artery disease, inability to perform physical exercise and non-diagnostic resting or exercise electrocardiography are indications for stress echo. The test is also used in symptomatic patients after revascularization or patients qualified for revascularization for functional assessment of coronary artery stenosis. Low-dose dobutamine test is usually performed in patients after myocardial infarction or with moderate-to-severe left ventricular dysfunction to assess myocardial viability before potential revascularization.

Reliability of three-dimensional color flow Doppler and two-dimensional pulse wave Doppler transthoracic echocardiography for estimating cardiac output after cardiac surgery

BackgroundThree-dimensional color flow Doppler (3DCF) is a new convenient technique for cardiac output (CO) measurement. However, to date, no one has evaluated the accuracy of 3DCF echocardiography for CO measurement after cardiac surgery. Therefore, this single-center, prospective study was designed to evaluate the reliability of three-dimensional color flow and two-dimensional pulse wave Doppler (2D-PWD) transthoracic echocardiography for estimating cardiac output after cardiac surgery.MethodsPost-cardiac surgical patients with a good acoustic window and a low dose or no dose of vasoactive drugs (norepinephrine < 0.05 μg/kg/min) were enrolled for CO estimation. Three different methods (third generation FloTrac/Vigileo™ [FT/V] system as the reference method, 3DCF, and 2D-PWD) were used to estimate CO before and after interventions (baseline, after volume expansion, and after a dobutamine test).ResultsA total of 20 patients were enrolled in this study, and 59 pairs of CO measurements were collected (one pair was not included because of increasing drainage after the dobutamine test). Pearson’s coefficients were 0.260 between the CO-FT/V and CO-PWD measurements and 0.729 between the CO-FT/V and CO-3DCF measurements. Bland-Altman analysis showed the bias between the absolute values of CO-FT/V and CO-PWD measurements was − 0.6 L/min with limits of agreement between − 3.3 L/min and 2.2 L/min, with a percentage error (PE) of 61.3%. The bias between CO-FT/V and CO-3DCF was − 0.14 L/min with limits of agreement between − 1.42 L /min and 1.14 L/min, with a PE of 29.9%. Four-quadrant plot analysis showed the concordance rate between ΔCO-PWD and ΔCO-3FT/V was 93.3%.ConclusionsIn a comparison with the FT/V system, 3DCF transthoracic echocardiography could accurately estimate CO in post-cardiac surgical patients, and the two methods could be considered interchangeable. Although 2D-PWD echocardiography was not as accurate as the 3D technique, its ability to track directional changes was reliable.

High sensitivity cardiac troponins: Can they help in diagnosing myocardial ischaemia?

Cardiac troponin is the most sensitive marker of myocardial injury, but controversy still exists about its role in detecting ischaemia. To investigate the role of troponin as a marker of stress-induced ischaemia, circulating high sensitivity cardiac troponin T (hs-cTnT) was measured and compared with the MB fraction of creatine kinase (CK-MB) in 125 patients undergoing a stress test (53 electrocardiogram/echo exercise, 42 echo dipyridamole and 30 echo dobutamine tests). Plasma concentrations of hs-cTnT increased after the tests in 90/125 patients, while an increase of CK-MB was seen in 31/125 patients ( p<0.0001). Overall, hs-cTnT significantly increased from 17.5±16.9 ng/l to 25.5±27.9 ng/l ( p<0.0001), without significant changes of CK-MB. Significant increments in hs-cTnT were documented after exercise test (from 15.9±11.9 ng/l to 19.5±13.6 ng/l, p<0.0001) and dobutamine test (from 20.6±20.8 ng/l to 37.8±31.1 ng/l, p=0.0006), in absence of changes in CK-MB according to each stressor. Among the 125 tests, 84 were diagnosed as negative and 41 as positive for myocardial ischaemia. Significant increments in hs-cTnT were detected after both negative (from 18.6±19.2 ng/l to 27.1±32.1 ng/l, p=0.0018) and positive test (from 15.2±10.8 ng/l to 22.3±16.2 ng/l, p=0.0005), without significant changes of CK-MB according to the test result. Despite a positive correlation between stress-induced increase of hs-cTnT and obstructive coronary artery disease, the release of troponin was observed also in a significant proportion of patients without coronary stenoses. Left ventricular hypertrophy markedly enhanced myocardial release of troponin. Circulating troponin increases in most patients undergoing a stress test, irrespective of the test result and of coronary artery disease. Plasma release of troponin depends on multiple pathogenetic mechanisms, making the biomarker a not reliable tool in detecting transient ischaemia.

Left ventricular deformation associated with cardiomyocyte Ca(2+) transients delay in early stage of low-dose of STZ and high-fat diet induced type 2 diabetic rats.

BackgroundIn the early stage of diabetes, the cardiac ejection fraction is preserved, despite the existence of the subclinical cardiac dysfunction to some extent. However, the detailed phenotype of this dysfunction and the underlying mechanism remain unclear. To improve our understanding of this issue, we used low-dose STZ and high-fat diet to induce type 2 diabetic models in rats. The effects and the mechanism associated with the early stages of the disease were analyzed.MethodsThe type 2 diabetic mellitus (T2DM) in SD rats were induced through 30 mg/kg STZ and high-fat diet. Two-dimensional spackle-tracking echocardiography (STE) and the dobutamine test were performed to examine the cardiac function. Calcium transients of left ventricular myocytes were detected and the related intracellular signalling factors were analyzed by western blotting.ResultsAfter 6-weeks, T2DM rats in left ventricular (LV) diastole showed decreased global and segment strain(S) levels (P < 0.05), both in the radial and circumferential directions. Strain rate (Sr) abatement occurred in three segments in the radial and circumferential directions (P < 0.05), and the radial global Sr also decreased (P < 0.05). In the systolic LV, radial Sr was reduced, except the segment of the anterior septum, and the Sr of the lateral wall and post septum decreased in the circumferential direction (P < 0.05). Conventional M-mode echocardiography failed to detect significant alterations of cardiac performance between the two groups even after 12 weeks, and the decreased ejection fraction (EF%), fractional shortening (FS%) and end-systolic diameters (ESD) could be detected only under stress conditions induced by dobutamine (P < 0.05). In terms of calcium transients in cardiac myocytes, the Tpeak in model rats at 6 weeks was not affected, while the Tdecay1/2 was higher than that of the controls (P < 0.05), and both showed a dose-dependent delay after isoproterenol treatment (P < 0.05). Western blot analysis showed that in 6-week T2DM rats, myocardial p-PLB expression was elevated, whereas p-CaMKII, p-AMPK and Sirt1 were significantly down-regulated (P < 0.05).ConclusionA rat model of T2DM was established by low dose STZ and a high-fat diet. LV deformation was observed in the early stages of T2DM in association with the delay of Ca2+ transients in cardiomyocytes due to the decreased phosphorylation of CaMKII. Myocardial metabolism remodeling might contribute to the early LV function and calcium transportation abnormalities.

Assessment of Left Ventricular Mechanics in Patients with Ischemic Heart Disease

The paper presents new ultrasound technology for assessment of left ventricular (LV) strain in the longitudinal, radial, and circumferential directions and the LV area strain at rest and during dobutamine stressechocardiography in patients with intermediate pretest probability of ischemic heart disease (IHD). Analysis was performed for the first time using real-time three-dimensional echocardiography (4D Strain). It was shown that in patients with single-artery left anterior descending artery (LAD) and left circumflex coronary artery (LCX) stenosis of 50% and more, the decreases in the global LV strain in the longitudinal, radial, and circumferential directions as well as in the LV strain area were observed at peak dobutamine stress in 4D Strain mode. Assessment of global LV strain in 4D Strain mode during dobutamine test had low sensitivity, specificity, and diagnostic accuracy in diagnosing single-vessel coronary artery disease.

My paper 20 years later: effects of dobutamine on the VO₂/DO₂ relationship.

Oxygen uptake (VO₂) is independent of oxygen delivery (DO₂) over a wide range of values, because Ov extraction can readily adapt to changes in DO₂. However, VO₂ can become DO₂-dependent in acute circulatory failure. Various methods of evaluating the presence of VO₂/DO₂ dependency were conducted, but criticized because of potential problems with mathematical coupling of data. Some 20 years ago, we proposed using a dobutamine test and showed similar relationships using direct and indirect measurements. Since these studies on the systemic VO₂/DO₂ relationship, investigators have also explored regional alterations. The relationship between VO₂ and DO₂ remains an important concept. Abnormal global VO₂/DO₂ dependency does not exist in stable, critically ill patients, but can exist in circulatory shock of all etiologies. It can also occur regionally in septic patients, and microcirculatory alterations may contribute. Patient management should be titrated individually with careful assessment to identify those who will benefit from increased DO₂.

Long-term risk stratification with low-dose dobutamine testing in asymptomatic low-flow patients with severe aortic stenosis and normal ejection fraction

Long-term risk stratification with low-dose dobutamine testing in asymptomatic low-flow patients with severe aortic stenosis and normal ejection fraction

138 Clinicians’ Referrals for Stress Echocardiography: Are we Compliant with Nice Guidelines?

IntroductionAccurate assessment of patients presenting with suspected cardiac pain is of paramount importance as it determines management strategy. Angina itself is a clinical diagnosis and assessing its prognostic significance may...

Preserved contractile reserve in a dobutamine test for the prediction of a response to resynchronisation therapy in ischaemic and non-ischaemic cardiomyopathy — A multicenter ViaCRT study

Preserved contractile reserve in a dobutamine test for the prediction of a response to resynchronisation therapy in ischaemic and non-ischaemic cardiomyopathy — A multicenter ViaCRT study

Contractile reserve assessed by dobutamine test identifies super-responders to cardiac resynchronization therapy.

IntroductionIn this study, we sought to determine whether myocardial contractile reserve (CR) assessed by dobutamine stress echocardiography (DSE) can identify patients who experience nearly complete normalization of left ventricular (LV) function after the implantation of a cardiac resynchronization therapy (CRT) pacemaker.Material and methodsThe study group consisted of 55 consecutive patients with non-ischemic dilated cardiomyopathy, LV ejection fraction (LVEF) < 35%, and prolonged QRS complex duration, who were scheduled for CRT pacemaker implantation. The DSE (20 µg/kg/min) was performed in all patients. The CR assessment was based on a change in the wall motion score index (ΔWMSI) and ΔLVEF during DSE. Super-response was defined as an increase in LVEF to > 50% and reduction in left ventricular end-systolic dimension to < 40 mm 12 months following the CRT implantation.ResultsA total of 7 patients (12.7%) were identified as super-responders to CRT. When compared to non-super-responders, these patients had significantly higher values of the dobutamine-induced change in ΔWMSI (1.031 ±0.120 vs. 0.49 ±0.371, p < 0.01), and ΔEF (17.9 ±2.2 vs. 8.8 ±6.2, p < 0.01). Receiver operating characteristic analysis showed that dobutamine-induced changes in ΔWMSI ≥ 0.7 and ≥ 14% for ΔEF are the best discriminators for a super-response. Patients with ΔWMSI ≥ 0.7 and ΔEF ≥ 14% are significantly less often hospitalized (p < 0.01) for worsening of heart failure during 28.5 ±3.0 months of the follow-up.ConclusionsContractile reserve assessed by DSE can identify patients with dilated cardiomyopathy who are likely to experience near normalization of LV function following CRT.

Prognostic value of low-dose dobutamine testing in asymptomatic patients with moderate or severe aortic stenosis and preserved ejection fraction

Purpose: In Aortic Stenosis (AS) most Doppler-echocardiographic indices that are used for assessing AS severity are flow dependent. The aim of this study was to assess prognostic value of low-dose Dobutamine Testing (DT) in patients with moderate or severe AS and preserved Ejection Fraction (EF). Method: A total of 126 asymptomatic patients with aortic valve area (AVA) ≤1.5 cm2 and EF >50% were enrolled in this prospective study. The follow-up period was 14±2 months. Mean age was 66.47±10.53; (58.73% males), mean EF was 72,03±6,69%, mean pressure gradient (Pmean) 41.94±11.22 mmHg and mean AVA 0.82±0.22 cm2. Patients with ≥2+ valvular regurgitation or more than mild mitral stenosis were excluded. The dobutamine infusion protocol was begun at 5 μg/kg/min body weight up to 20 μg/kg/min, titrated upwards at steps of 5 μg/kg/min every 3 min. The composite outcome endpoint (MACE) was defined as cardiac death, aortic valve replacement and hospitalization caused by AS symptoms according to patient's medical record. Results: No patient experienced a serious adverse event during or after DT. A total of 70 patients had MACE (55.55%), of which 9 patients (7.14%) have died during follow-up. Out of 70 patients, 56 patients (80%) had an Aortic Valve Replacement (RAV). Patients who had an increase in AVA during DT ≤0.2 cm2 and/or final AVA ≤1 cm2 had more often RAV (hi=9.5311; df=1; p=0.002). The lasso penalized Cox regression, conducted solely on the variables at rest, showed that the greatest predictive capacity has the aortic valve resistance (AVR). At the same time, the AUC for the all analyzed pre-dobutamine variables combined, evaluated at time = 12 months, was 0.76. On the other hand, the L1 procedure, when applied on all variables (pre and during DT), chooses only dobutamine variables as the most valuable in predictive sense, improving AUC by 6% (AUC =0.82, at time = 12 months). The value of the AVR obtained during the DT was the strongest independent one-year MACE predictor (according to bootstrapped p values) of all pre and during DT varaibles, with the value of 195.12 dynes s cm-5 having the highest sensitivity ans specificity in predicting MACE (0.78 and 0.73 respectively). In addition, patients who have experienced symptoms (11/126, 8.73%) during DT had more often MACE comparing to asymptomatic patients (hi=6,7408; p<0,001; df=1). Conclusion: The present study demonstrates that AVR, as well as flow-mediated changes during DT, can provide new, clinically relevant information in terms of outcome and timing of valve replacement in asymptomatic patients with moderate and severe AS and preserved EF.

Screening for the Presence of Coronary Artery Disease

Screening for the Presence of Coronary Artery Disease

Point/Counterpoint

Point/Counterpoint