Dipyridamole Stress Test Research Articles

Relation between high-sensitivity troponin i serum levels and myocardial ischemia in patients with suspected chronic coronary syndrome: the RESET-MI study

Abstract Background Previous studies showed that exercise may increase cardiac troponin serum levels; however, whether exercise-induced myocardial ischemia influences the exercise-induced increase of troponin levels remains debatable. Methods We prospectively enrolled consecutive patients undergoing an elective stress myocardial perfusion scintigraphy (MPS) because of a clinical suspicion of obstructive coronary artery disease (CAD). Patients were divided into 3 groups according to the evidence and degree of stress-induced myocardial ischemia at MPS: 1) Group 1, no ischemia (≤4% of myocardium); 2) Group 2, mild ischemia (5-10%); 3) Group 3, moderate-to-severe myocardial ischemia (≥10%). High-sensitivity cardiac troponin I (cTnI) was measured immediately before (T0) and 1 hour (T1) and 4 hours (T2) after the stress test. A successive evaluation of patients was performed at 24 months. Results One-hundred consecutive patients (64 males; age 65.5±9.5 years) were enrolled in the study. An exercise stress test and a dipyridamole stress test were performed in 81 and 19 patients, respectively. Serum hs-cTnI concentrations significantly increased after stress test, compared to baseline, in the whole population, from (median, interquartile range) 3.9 (2.5-6.1) ng/L at T0, to 4.2 (2.8-7.3) ng/L at T1 (p<0.001) and 6.7 (3.8-14.1) ng/L at T2 (p<0.001 vs. both T0 and T1). The increase in hs-cTnI did not significantly differ between the 3 groups (p=0.35; Figure). The increase was significant after both exercise (+54.5%) and dipyridamole (+18.2%), although the increase was greater after exercise (p=0.002). Heart rate achieved during the test was the strongest determinant of cTnI increase after the stress test (p < 0.001). Conclusions In patients with suspected CAD, stress MPS induces an increase of cTnI that is independent of the induction and severity of myocardial ischemia and is mainly related to myocardial work, as indicated by heart rate achieved during the stress test.Figure

Diagnosis of cardiovascular disease in patients with chronic kidney disease.

Patients with chronic kidney disease (CKD) are at high risk of cardiovascular disease (CVD) and cardiovascular death. Identifying and monitoring cardiovascular complications and hypertension is important for managing patients with CKD or kidney failure and transplant recipients. Biomarkers of myocardial ischaemia, such as troponins and electrocardiography (ECG), have limited utility for diagnosing cardiac ischaemia in patients with advanced CKD. Dobutamine stress echocardiography, myocardial perfusion scintigraphy and dipyridamole stress testing can be used to detect coronary disease in these patients. Left ventricular hypertrophy and left ventricular dysfunction can be detected and monitored using various techniques with differing complexity and cost, including ECG, echocardiography, nuclear magnetic resonance, CT and myocardial scintigraphy. Atrial fibrillation and other major arrhythmias are common in all stages of CKD, and ambulatory heart rhythm monitoring enables precise time profiling of these disorders. Screening for cerebrovascular disease is only indicated in asymptomatic patients with autosomal dominant polycystic kidney disease. Standardized blood pressure is recommended for hypertension diagnosis and treatment monitoring and can be complemented by ambulatory blood pressure monitoring. Judicious use of these diagnostic techniques may assist clinicians in detecting the whole range of cardiovascular alterations in patients with CKD and enable timely treatment of CVD in this high-risk population.

INOCA: Non-Invasive Assessment of the Pathophysological Mechanisms Using CZT-SPECT

Background: One of the causes of INOCA (Ischemia with Non- Obstructive Coronary Arteries) is microvascular dysfunction (MVD), which can be noninvasively assessed through the quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR). Dynamic myocardial perfusion imaging (MPI) by CZT-SPECT at rest, with dipyridamole stress test and cold pressor test (CPT) can establish the presence of two different pathophysiological mechanisms of MVD: endothelium-independent or endothelium-dependent, respectively. Objectives: The aim of this study was to evaluate the usefulness of CZT-SPECT for the diagnosis of MVD and the different mechanisms involved in patients with INOCA. Materials and Methods: A total of 93 consecutive INOCA patients were prospectively included and underwent dynamic MPI with CZT-SPECT at rest and with dipyridamole stress test and CPT. THe MBF was quantified using 4DM® software. A MFR response to dipyridamole <2, and changes in MBF (ΔMBF) <1.5 with CPT were considered abnormal responses. MVD was defined in the presence of one abnormal response or both. Results: CZT-SPECT detected MVD in 85% (n = 79) of the patients with INOCA. Forty-two percent had an abnormal response to both stressors while 43% presented an abnormal response of MBF only with CPT. Conclusion: The use of CZT-SPECT with both stress tests allowed the evaluation of different possible pathophysiological mechanisms of MVD present in most patients with INOCA

Reduced Heart Rate Response during Drug-Induced Stress Is Related to the Severity of Perfusion Defect

Introduction: During the pharmacological stress test with dipyridamole, a normal hemodynamic response is slightly reduced blood pressure and raised heart rate (HR). However, sometimes the HR response is reduced. This study investigated the relationship between the HR response during the dipyridamole stress test and the severity of the perfusion defects using Thallium 201 myocardial perfusion imaging. Methods: We enrolled 50 patients undergoing dipyridamole stress at the nuclear cardiology Lab, Main University Hospital of Alexandria. Standard dipyridamole protocol (infusion over 4 min) and standard thallium 201 protocol (2 min after dipyridamole infusion) were followed. If the heart rate (HR) ratio (peak HR/rest HR) was 1.20 or less, it was considered a reduced response. Total perfusion defect (TPD), summed stress score (SSS), summed rest score (SRS), and summed difference score (SDS) for myocardial perfusion were calculated. Patients with reduced HR response and normal HR responses were compared and independent predictors of reduced HR response were determined. Results: About 56% of patients had reduced HR response; which included a high number of patients with a history of dyslipidemia and diabetes mellitus. The reduced HR response group showed lower SSS, SRS. The analysis showed that the independent predictors of reduced HR response were rest HR, SSS, and diabetes mellitus. Conclusions: Reduction in the HR response during the dipyridamole-induced stress test is related to the severity of perfusion defect, diabetes mellitus, and Dyslipidemia.

Guidance and Best Practices for Nuclear Cardiology Laboratories During the COVID-19 Pandemic: An Information Statement From ASNC and SNMMI.

Guidance and Best Practices for Nuclear Cardiology Laboratories During the COVID-19 Pandemic: An Information Statement From ASNC and SNMMI.

Myocardial strain indices and coronary flow reserve are only mildly affected in healthy hypertensive patients.

To investigate changes in two-dimensional myocardial strain echocardiography (2DSTE) indices following a dipyridamole stress test (DIPSE) in relatively healthy hypertensive patients and healthy controls. Forty-seven male hypertensive patients (aged 57±9years) with normal ejection fraction and without left ventricular (LV) hypertrophy and 20 healthy male subjects were studied with conventional and 2DSTE echocardiography at rest and post DIPSE. Coronary flow reserve (CFR) in the left anterior descending artery following DIPSE was also evaluated. Global longitudinal strain (GLS) and TWIST were higher while UNTWIST rate was lower in hypertensives versus controls (p < 0.05 for all); TWIST remained higher in hypertensives (p = 0.021) after adjustment for differences in age and body mass index (BMI) between the groups. CFR was higher in controls compared to hypertensives even after adjustment for confounders (4.14 vs. 2.53, p = 0.001). DIPSE-induced changes did not differ between the groups after adjustment for age and BMI (p > 0.05 for all). DIPSE-induced improvement in GLS was associated with higher CFR only in hypertensive patients (r - 0.372, p = 0.010). The current study showed that well controlled hypertensive patients have only mild echocardiographic differences compared to controls; some of these differences appear to depend on age and BMI. A 'hyper-rotation' phenomenon (i.e. higher TWIST) early in hypertension may be a compensatory mechanism to preserve global systolic LV function. Coronary microcirculatory function was impaired in hypertensive patients, albeit within normal range, and was associated with DIPSE-induced changes in myocardial long-axis systolic function.

Considerations for Stress Testing Performed in Conjunction with Myocardial Perfusion Imaging.

For myocardial perfusion imaging (MPI), the best test to evaluate hemodynamic changes during stress is an exercise treadmill test. It provides independent prognostic value, including evaluation of total exercise time, performance, and capacity; heart rate response during exercise, with ischemia, and in recovery; blood pressure response; myocardial oxygen demand; and assessment of symptoms. Combining these exercise data with perfusion imaging provides the best prognostic value and risk stratification for patients. Although exercise stress testing accompanied by MPI is preferential, it is not always possible since an increasing number of patients cannot exercise to a maximal (symptom-limited) level. Further, there is much evidence in the literature demonstrating a suboptimal, non-symptom-limited (not achieving at least 4-6 min or <85% of maximum predicted heart rate) exercise test performed as part of an MPI study may result in a false-negative outcome. Therefore, pharmacologic stress agents provide an excellent alternative for those patients who cannot achieve an adequate heart rate response or adequately perform physical exercise. This article focuses on considerations for performing stress (exercise and pharmacologic) testing in conjunction with MPI. It is meant to provide a basic overview of the principles of exercise stress testing; discuss the indications, contraindications, patient preparation, and protocols for exercise stress testing; discuss the contraindications, administration protocols, and side effects for vasodilator (adenosine, dipyridamole, and regadenoson) stress testing; and discuss the contraindications, administration protocols, and side effects for dobutamine stress testing.

Heart rate reserve during dipyridamole stress test applied to potential heart donors in brain death

A blunted heart rate reserve (HRR) during dipyridamole stress echocardiography (DSE) is a prognostically unfavorable sign of cardiac autonomic dysfunction. Short-term adjustments of heart rate (HR) are thought to rise from changes in neural input to the heart. DSE is applied in potential heart donors to rule out underlying coronary artery disease and left ventricular dysfunction. The aim of this study is to assess HRR during DSE in brain death. We enrolled two groups: group 1 (N.=49, 22 men, 54.6±8.8 years) with patients in brain death enrolled in the nationwide marginal donor heart recruiting program; group 2 (N.=49, 18 men, 66.4±12.0 years) referred to DSE for suspected or known coronary artery disease. All underwent DSE (0.84 mg/kg in 6') by quality-controlled readers certified via web-based training (1487/CE Lazio-1). We assessed left ventricular contractile reserve (LVCR) as stress/rest ratio of force (systolic blood pressure/end-systolic volume). HRR was calculated as the peak/rest HR ratio from 12-lead EKG. The two study groups were similar for prevalence of inducible ischemia (4/49 vs. 9/49, P=NS). Group 1 showed higher resting HR (group 1: 88.1±15.5 bpm vs. group 2: 66.5±11.5 bpm, P<0.01) and similar peak HR (group 1: 94.7±15.3 bpm vs. group 2: 89.5±19.3 bpm, P=0.144), with blunted HRR (group 1: 1.08±0.10 bpm vs. group 2: 1.36±0.31 bpm, P<0.01). HRR was unrelated to LVCR. HRR is almost abolished and unrelated to LVCR in brain-dead patients during DSE. The modulation of neural input to the heart is essential to determine HRR, and plays no significant role in determining the inotropic response during DSE.

The prognostic role of myocardial strain indices and dipyridamole stress test in renal transplantation patients.

Renal transplantation (RT) increases survival in end-stage kidney disease patients but cardiovascular diseases remain the leading cause of morbidity and mortality. We evaluated the role of myocardial strain (2DSTE) indices and dipyridamole-induced (DIPSE) changes in echocardiographic parameters at baseline for the prediction of clinical events and echocardiographically assessed deterioration of cardiac function in a RT population. Forty-five RT patients underwent an echocardiographic study at baseline including 2DSTE and DIPSE. If no cardiovascular/renal event occurred, patients were investigated at 3-year follow-up; eight patients presented a clinical event while 37 patients were re-evaluated. Coronary flow reserve (CFR) was abnormal in 24% of the population. DIPSE induced improvements in classic and 2DSTE systolic and diastolic echocardiographic indices including TWIST, UNTWIST, global longitudinal strain (GLS), and circumferential strain (P<.05 for all). Compared to baseline, deteriorations in E/E', LVEF, E', and TWIST were observed at follow-up (P<.05 for all). DIPSE-induced changes in GLS, global radial strain, and LVEF were associated with changes in these indices at follow-up (P<.05 for all). Higher LV mass index, E/E', and lower MAPSE, E', and CFR at baseline were associated with the occurrence of clinical events at follow-up (P<.05 for all). In RT patients, coronary vascular dysfunction (ie, low CFR) was associated with the occurrence of adverse events. DIPSE-induced changes in myocardial strain and classic echocardiographic indices could identify individuals with a subclinical deterioration in cardiac function at follow-up. This may indicate that DIPSE could serve as a means to assess myocardial reserve in this population.

Exercise and pharmacologic stress-induced interlead T-wave heterogeneity analysis to detect clinically significant coronary artery stenosis

BackgroundDespite widespread use of ETT and vasodilator-stress with myocardial perfusion imaging (MPI) for noninvasive detection of flow-limiting coronary artery disease, there is continued need to improve diagnostic accuracy. We examined whether measurement of interlead T-wave heterogeneity (TWH) during exercise tolerance testing (ETT) or pharmacologic stress testing improves detection of stenoses in large epicardial coronary arteries. MethodsAll 137 patients at our institution who underwent diagnostic coronary angiography within 0 to 5 days after ETT (N = 81) or dipyridamole IV infusion (N = 58) in 2016 were studied, including 2 patients with both tests. Cases (N = 93) had angiographically significant stenosis (≥50% of left main or ≥ 70% of an epicardial coronary artery ≥2 mm in diameter); controls (N = 44) did not. TWH, i.e., interlead splay of T waves, was determined by second central moment analysis from precordial leads by an investigator blinded to angiographic results. ResultsAt rest, TWH levels were similar for cases and controls. ETT and dipyridamole stress testing increased TWH by 69% (p < 0.0001) and 27% (p < 0.0001), respectively, in cases. In controls, TWH did not change. Areas under the ROC curves for TWH increase for any flow-limiting coronary artery stenosis were 0.737 (p < 0.0001) for ETT and 0.818 (p < 0.0001) for dipyridamole stress testing. By contrast, neither ST-segment changes during ETT (p = 0.12) nor MPI during dipyridamole stress testing (p = 0.60) discriminated cases from controls. ConclusionsTWH measurement is a novel method that improves detection of angiographically confirmed flow-limiting stenoses in large epicardial coronary arteries during both ETT and MPI during pharmacologic stress testing with dipyridamole.

Predictive and prognostic value of left ventricular mechanical dyssynchrony assessed by myocardial perfusion single photon emission computed tomography in asymptomatic patients under hemodialysis.

Patients under hemodialysis (HD) have an increased risk of major adverse cardiac events (MACEs). In these patients, myocardial perfusion scintigraphy (MPS) provides useful prognostic information. Left ventricular mechanical dyssynchrony (LVD) has been proven to predict all-cause death in patients under HD. It remains unclear, whether the same prognostic value pertains also to the prediction of MACEs. Ninety patients under HD (duration range: 2-216 months) with neither history nor symptoms of coronary artery disease at the time of MPS were retrospectively evaluated. All underwent clinical evaluation and MPS with dipyridamole stress test. MPS was reprocessed to derive left ventricular ejection fraction (EF), perfusion scores [summed stress score (SSS) and summed difference score (SDS)] and LVD (phase histogram bandwidth and phase SD).ResultsMACEs were reported in 10 (11.1%) patients as assessed at more than 2 years of follow-up (median 29 months). At univariate analysis, a correlation was demonstrated between MACEs and LVD (P<0.001), BMI (P=0.04), ECG changes during stress (P=0.03), dyspnea (P=0.02), SSS (P=0.04) and SDS (P=0.02). At stepwise multivariate analysis, only LVD (P<0.001), SSS (P=0.01) and SDS (P=0.001) were independent predictors of MACEs. No thresholds of SSS or SDS showed predictive value (P=0.79 for SSS ≥4, P=0.10 for SSS >8 and P=0.66 for SDS ≥2). At survival analysis, patients with LVD had a significantly shorter MACE-free survival (P<0.001). This predictive value held true even in patients with an unremarkable pattern of perfusion. In asymptomatic patients without known coronary artery disease under HD, LVD is highly predictive of the onset of MACEs at more than 2 years of follow-up and provides incremental value over perfusion scores alone. A phase analysis on gated MPS should be routinely performed in these patients to yield useful prognostic information.

Validation of early image acquisitions following Tc-99 m sestamibi injection using a semiconductors camera of cadmium-zinc-telluride

BackgroundCadmium-zinc-telluride (CZT) cameras allow to decrease significantly the acquisition time of myocardial perfusion imaging (MPI), but the duration of the examination is still long. Therefore, this study was performed to test the feasibility of early imaging following injection of Tc-99 m sestamibi using a CZT camera. MethodsSeventy patients underwent both an early and a delayed image acquisition after exercise stress test (n = 30), dipyridamole stress test (n = 20), and at rest (n = 20). After injection of Tc-99 m sestamibi, the early image acquisition started on average within 5 minutes for the exercise and rest groups, and 3 minutes 30 seconds for the dipyridamole group. Two independent observers evaluated image quality and extracardiac uptake on four-point scales. The difference between early and later images for each patient was scored on a five-point scale. ResultsThe image quality and extracardiac uptake of early and delayed image acquisitions were not different for the three groups (P > .05). There was no significant difference between early and delayed image acquisitions in the exercise, dipyridamole, and rest groups, respectively, in 63%, 40%, and 80% of cases. In the exercise group and rest group, a defect was only present in early MPI, respectively, in 13% and 20% of cases. A defect was only present in delayed images in 10% of cases in the exercise group and in 45% of cases in the dipyridamole group. ConclusionsThere was no difference between early and later image acquisitions in terms of quality. This protocol reduces the length of the procedure for the patient. Beginning with early image acquisitions may help to overcome the artifacts that are observed at the delayed time.

Heart Rate Response to Dypiridamole Stress in Relation to Perfusion and Function during Gated Technetium Tc99 M Sestamibi Spect Study

Objectives: A mild decrease in blood pressure and increase in heart rate (HR) are considered normal hemodynamic responses to dipyridamole. In this study, we tried to investigate the relation between the responses of heart rate to dipyridamole stress test with left ventricular perfusion and function data obtained from myocardial perfusion scintigraphy. Methods: Forty consecutive patients undergoing dipyridamole stress Technetium - 99m (Tc 99m) Sesta MIBI gated myocardial perfusion single photon emission computed tomography (SPECT) at the nuclear cardiology Lab of the cardiology department of the main university hospital of Alexandria University were prospectively enrolled from July 2013 for 6 months. Dipyridamole was infused over 4 min and TC 99m Sesta MIBI was injected 2 min after the end of infusion. Blunted heart rate response to dipyridamole considered if the HR ratio (peak HR/rest HR) was 1.20 or less. Summed stress score (SSS), summed rest score (SRS), and summed difference score (SDS) for myocardial perfusion in addition to total perfusion defect TPD, ejection fraction and territory of perfusion defect were obtained.Patients were grouped according to HR response and groups were compared. A logistic regression analysis was used to determine independent predictors of reduced HR response. Results: Blunted heart rate response was found in 67.5 % of patients. Patients with abnormal heart rate response were more frequently had a history of diabetes mellitus (X2 = 4.01). High baseline heart rate (t = 1.9), low post stress ejection fraction (t = 3.21) and perfusion defect in left circumflex territory (X 2 = 4.01) was found in blunted heart rate response group more than normal group. Conclusion: Severe perfusion defectis associated with blunted heart rate group as left ventricular dysfunction is associated with reduced chronotropic response to dipyridamole.Diabetes mellitus and cardiac autonomic neuropathy may reflect higher baseline heart rate.

Dipyridamole Stress Echocardiography Does Not Trigger Release of Highly-Sensitive Troponin I and T

Summary Background: The patients with episodes of chest pain and no electrocardiographic or biomarker abnormalities are currently monitored and subjected to non-invasive testing. Stress echocardiography is one of the most often used provocative tests, being the most cost- and risk-effective imaging technique. Some concerns about this technique have been raised regarding potential drug-induced myocardial injury. Our study hence aimed to establish whether or not dipyridamole stress echocardiography elicits release of troponin I (TnI) and T (TnT), as reliable bio-markers of myocardiocyte injury. Methods: Thirty-two patients, after exclusion of ongoing acute coronary syndrome (ACS) during evaluation in the emergency department (ED), were studied with echocar-diography both at the baseline and after pharmacological stress with dipyridamole. Results: All subjects had biomarkers assessment immediately before the stress-test (T1), 1 h from conclusion of the test (T2), and 6 h afterwards (T3). Cardio specific troponins were assessed with one contemporary-sensitive (TnI) and two highly-sensitive (HS) methods (HS-TnI and HS-TnT). The concentration of TnI, HS-TnI and HS-TnT did not differ throughout the three time points. At no time point the concentration of either HS-TnI or HS-TnT was significantly different among patients with negative or positive stress test. Conclusions: The data shows that dipyridamole stress testing does not trigger release of troponin in patients with and without inducible reversible ischemia.

Influence of dipyridamole stress echocardiography on galectin-3, amino-terminal B-type natriuretic peptide (NT-proBNP) and high-sensitivity troponin T

Objective Non-invasive assessment using a pharmacological provocative test is an essential part of the workup of patients admitted to the emergency department with chest pain. Some doubts, however, remain about the safety of dipyridamole stress echocardiography in patients with non-diagnostic troponin and ECG.Methods and results Twenty-nine consecutive patients admitted to the emergency department with chest pain and no evidence of acute coronary syndrome were subjected to standard dipyridamole stress echocardiography. Blood samples for measurement of galectin-3, NT-proBNP and high-sensitivity troponin T (HS-TnT) were collected at the baseline and after provocative testing. The provocative test was positive in 7/29 patients. As compared with baseline measurements, no signifi cant diff erences were observed in 1-h values of HS-TnT (10.7 versus 10.5 ng/L; P= 0.085) and galectin-3 (14.3 versus 13.7 ng/mL; P= 0.128), whereas values of NT-proBNP were slightly higher (126 versus 111 ng/L; P= 0.002). The 1-h delta variation of patients with a positive provocative test was signifi cantly higher than that of patients with negative provocative testing for galectin-3 (1.12 versus 1.00; P< 0.001), but not for HS-TnT (0.98 versus 1.00; P= 0.184) and NT-proBNP (1.10 versus 1.04; P= 0.344). The 1-h delta variation of galectin-3 was > 1 in all patients with a positive provocative test as compared with 50% of patients with a negative provocative test (P = 0.018).Conclusions Dipyridamole stress testing did not trigger clinically meaningful injuries to the myocardium. Galectin-3 testing may hence be preliminarily regarded as a complementary means for enhancing the diagnostic value of provocative testing. It is also worthwhile investigating whether patients with abnormal response to a provocative test and increased galectin-3 values may be targeted with specifi c therapy.

PROGNOSTIC SIGNIFICANCE OF ABNORMAL ELECTROCARDIOGRAPHIC CHANGES DURING REGADENOSON STRESS TESTING IN PATIENTS UNDERGOING MYOCARDIAL PERFUSION IMAGING

Ischemic electrocardiographic (IECG) changes during Regadenoson stress testing are uncommon but its clinical significance is unclear. Recent studies with dipyridamole and adenosine stress testing have reported a benign prognosis in the setting of IECG and normal myocardial perfusion imaging (NMPI).

Association of hemodynamic response during dipyridamole stress testing with 99mTc-MIBI SPET myocardial perfusion image findings.

The aim of this study was to assess whether there is an association between changes in the heart rate and blood pressure after dipyridamole stress and abnormal scan findings detected with gated technetium-99m methoxy isobutylisonitrile (99mTc-MIBI) myocardial perfusion imaging (MPI). A total of 200 consecutive patients with known or suspected coronary artery disease underwent MPI using a 2 days stress/rest protocol. Heart rate (HR), blood pressure and electrocardiogram were monitored during the stress study. Dipyridamole-induced increase in HR ratio (peak HR/baseline HR) of more than 1.20 and decrease in systolic blood pressure (SBP) of 10 mmHg or more were defined as a normal response. Low ejection fraction (EF) was defined as EF less than 45%. Semi-quantitative measures used include summed stress score (SSS), summed difference score (SDS), end systolic volume (ESV) and left ventricular ejection fraction (LVEF). Chi-square-and regression analysis was used to assess associations between the various hemodynamic parameters and MPI abnormalities. Our results showed that 75% of patients had abnormal scans. Statistically significant associations were observed between each of the following factors and abnormal scan findings: abnormal SBP response to dipyridamole (P=0.011), increased SSS (P=0.040) and low LVEF (P=0.012). A significant association was also observed between decreased HR response and low LVEF (P=0.012). In conclusion, this study demonstrated that an abnormal hemodynamic response during dipyridamole stress test was associated with abnormal myocardial perfusion imaging scan findings, low LVEF and SSS.

Impact of caffeine ingestion on dipyridamole myocardial perfusion gated SPECT study

IntroductionDipyridamole is increasingly used for vasodilatation stress test. Caffeine diminishes its effect. At present, there is still no consensus as to whether and how long caffeine should be interrupted. We hypothesized that caffeine impacts the dypyridamole gated MPS findings in patients with coronary artery disease. MethodsThirty-six patients who had >50% stenosis in at least one vessel on coronary angiography (CAG) were included in our study. Gated MPS with standard dipyridamole stress test was used to assess myocardial perfusion defects and LVEF values before and after caffeine ingestion. Myocardial perfusion images and gated analyses were assessed visually and quantitatively. The results were analyzed by the t test for paired observations. ResultsThe mean serum caffeine levels were significantly higher 1 h after caffeine ingestion (1.10 ± 0.05 mg/L vs. 5.82 ± 1.80 mg/L) (p < 0.05). Heart rates and blood pressures changed significantly at both baseline and caffeine dipyridamole stress tests (p ≤ 0.05). The percentage of total perfusion defects (62%) at baseline gated MPS images was significantly higher than gated MPS with caffeine (34%) (p < 0.05). The LVEF was not significantly different between baseline dipyridamole (67.25 ± 2.61) and caffeine dipyridamole (63.81 ± 2.41) gated MPS studies. The mean transient ischemic dilatation (TID) was significantly lower at dipyridamole stress MPS (0.98 ± 0.01) than caffeine dipyridamole stress MPS (1.05 ± 0.02) (p ≤ 0.05). ConclusionsWe demonstrated that caffeine may cause attenuation of extent and severity of myocardial perfusion abnormalities during dipyridamole stress gated MPS study. Thus, patients should refrain from caffeine at least 1 day before the test.

Comparison of Sulfur Hexafluoride Microbubble (SonoVue)-Enhanced Myocardial Contrast Echocardiography With Gated Single-Photon Emission Computed Tomography for Detection of Significant Coronary Artery Disease: A Large European Multicenter Study

The purpose of this study was to compare sulfur hexafluoride microbubble (SonoVue)-enhanced myocardial contrast echocardiography (MCE) with single-photon emission computed tomography (SPECT) relative to coronary angiography (CA) for assessment of coronary artery disease (CAD).Small-scale studies have shown that myocardial perfusion assessed by SonoVue-enhanced MCE is a viable alternative to SPECT for CAD assessment. However, large multicenter studies are lacking.Patients referred for myocardial ischemia testing at 34 centers underwent rest/vasodilator SonoVue-enhanced flash-replenishment MCE, standard (99m)Tc-labeled electrocardiography-gated SPECT, and quantitative CA within 1 month. Myocardial ischemia assessments by 3 independent, blinded readers for MCE and 3 readers for SPECT were collapsed into 1 diagnosis per patient per technique and were compared to CA (reference standard) read by 1 independent blinded reader.Of 628 enrolled patients who received SonoVue (71% males; mean age: 64 years; >1 cardiovascular [CV] risk factor in 99% of patients) 516 patients underwent all 3 examinations, of whom 161 (31.2%) had ≥70% stenosis (131 had single-vessel disease [SVD]; 30 had multivessel disease), and 310 (60.1%) had ≥50% stenosis. Higher sensitivity was obtained with MCE than with SPECT (75.2% vs. 49.1%, respectively; p < 0.0001), although specificity was lower (52.4% vs. 80.6%, respectively; p < 0.0001) for ≥70% stenosis. Similar findings were obtained for patients with ≥50% stenosis. Sensitivity levels for detection of SVD and proximal disease for ≥70% stenosis were higher for MCE (72.5% vs. 42.7%, respectively; p < 0.0001; 80% vs. 58%, respectively; p = 0.005, respectively).SonoVue-enhanced MCE demonstrated superior sensitivity but lower specificity for detection of CAD compared to SPECT in a population with a high incidence of CV risk factors and intermediate-high prevalence of CAD. (A phase III study to compare SonoVue® enhanced myocardial echocardiography [MCE] to single photon emission computerized tomography [ECG-GATED SPECT], at rest and at peak of low-dose Dipyridamole stress test, in the assessment of significant coronary artery disease [CAD] in patients with suspect or known CAD using Coronary Angiography as Gold Standard-SonoVue MCE vs SPECT; EUCTR2007-003492-39-GR).

The research on endothelial function in women and men at risk for cardiovascular disease (REWARD) study: methodology

BackgroundEndothelial function has been shown to be a highly sensitive marker for the overall cardiovascular risk of an individual. Furthermore, there is evidence of important sex differences in endothelial function that may underlie the differential presentation of cardiovascular disease (CVD) in women relative to men. As such, measuring endothelial function may have sex-specific prognostic value for the prediction of CVD events, thus improving risk stratification for the overall prediction of CVD in both men and women. The primary objective of this study is to assess the clinical utility of the forearm hyperaemic reactivity (FHR) test (a proxy measure of endothelial function) for the prediction of CVD events in men vs. women using a novel, noninvasive nuclear medicine -based approach. It is hypothesised that: 1) endothelial dysfunction will be a significant predictor of 5-year CVD events independent of baseline stress test results, clinical, demographic, and psychological variables in both men and women; and 2) endothelial dysfunction will be a better predictor of 5-year CVD events in women compared to men.Methods/DesignA total of 1972 patients (812 men and 1160 women) undergoing a dipyridamole stress testing were recruited. Medical history, CVD risk factors, health behaviours, psychological status, and gender identity were assessed via structured interview or self-report questionnaires at baseline. In addition, FHR was assessed, as well as levels of sex hormones via blood draw. Patients will be followed for 5 years to assess major CVD events (cardiac mortality, non-fatal MI, revascularization procedures, and cerebrovascular events).DiscussionThis is the first study to determine the extent and nature of any sex differences in the ability of endothelial function to predict CVD events. We believe the results of this study will provide data that will better inform the choice of diagnostic tests in men and women and bring the quality of risk stratification in women on par with that of men.