The Association of Dipyridamole Side Effects with Hemodynamic Parameters, ECG Findings, and Scintigraphy Outcomes

The effects of carvedilol, metoprolol and propranolol on cisplatin-induced kidney injury

The β-adrenoceptor blockers may have anti-oxidant properties or induce β-arrestin recruitment beyond classical desensitization of receptor/G protein coupling, offering potential therapeutic benefits. Here, we investigated the effects of carvedilol, metoprolol and propranolol in an animal model of cisplatin-induced nephrotoxicity. Rats received the β-blockers (3 or 12 mg/kg/day) with or without cisplatin, and kidney function was investigated using renal scintigraphy, histopathology, and serum variables. Metoprolol and propranolol as well as low-dose carvedilol did not alter kidney function, per se. Meanwhile, high-dose carvedilol reduced renal accumulation of Technetium-99m (99mTc)-labeled dimercaptosuccinic acid (99mTc-DMSA) without significant effect on other variables. Furthermore, low-dose carvedilol prevented cisplatin-induced reduction of tracer uptake, but high-dose of this drug aggravated the situation. In this regard, both low and high -doses of carvedilol significantly inhibited cisplatin effects on kidney histology, BUN and creatinine levels. Also, high-dose propranolol inhibited cisplatin adverse effects on radiotracer uptake, histological manifestations, BUN and creatinine levels, while metoprolol failed to cause a notable effect. Taken together, carvedilol and high-dose propranolol may offer potential benefits in cisplatin nephrotoxicity.

Relationship between gated myocardial perfusion SPECT findings and hemodynamic, electrocardiographic, and heart rate changes after Dipyridamole infusion

After dipyridamole infusion, electrocardiographic (ECG), blood pressure and heart rate (HR) changes were seen. We tried to investigate whether there is a relationship between hemodynamic, ECG and HR changes after dipyridamole infusion and gated myocardial perfusion SPECT findings. We studied 206 consecutive patients which underwent a 2-day protocol Dipyridamole Stress/Rest Tc99m-Sestamibi gated myocardial perfusion SPECT. Systolic blood pressure (SBP), diastolic blood pressure (DBP), HR and ECG were recorded. HR was mildly increased while SBP and DBP were mildly decreased after Dipyridamole infusion. There was only statistically significant difference between ECG changes as well as transient ischemic dilation (TID) ratio between normal scans and scans with ischemia (P = 0.02 and P = 0.01 respectively). There was correlation between these variables and summed stress score (SSS) and summed difference score (SDS). Patients with ischemia in their scans, 44.3% had ST depression after Dipyridamole infusion. Also ST depression most frequently was seen in patients with left anterior descending artery disease. From patients with abnormal scan + ST depression after Dipyridamole infusion (33 patient), 27 patient (81.81%) had ischemia. There was an association between TID ratio as well as ECG changes after Dipyridamole infusion and SSS, SDS and coronary artery territory abnormality. Difference between calculated left ventricular ejection fraction using stress and rest images had significant correlation with SSS and SDS. ST depression after Dipyridamole infusion and TID ratio had association with ischemia, SSS and SDS. So in equivocal Gated SPECT findings, they could be very useful for interpretation.

Dipyridamole-induced adverse effects in myocardial perfusion scans: Dynamic evaluation

AIM AND BACKGROUND

Dipyridamole-induced stress myocardial perfusion scans (MPS) has been widely used for management of coronary artery disease. The adverse effects of dipyridamole and other stress agents have been evaluated. The aim of this research is to confirm the dynamic data on dipyridamole side effects during MPS.

METHODS

We collected data of 183 patients who underwent dipyridamole-induced stress MPS by retrospectively reviewing their clinical records, which included the severity of dipyridamole side effects in 3 min, 10 min, and 20 min after infusion. The incidence and severity at all three points, including the effect of age and gender, were obtained.

RESULTS

Adverse effects occurred in 96 patients (69.6%). The most frequent symptoms were dizziness (42.8%), chest tightness (24.6%), abdominal pain (18.1%), and headache (15.2%). Most symptoms were Grade 1 to 2, according to the grading system for common terminology criteria. The median duration of symptom persistence was 36 min, not significantly different among age and gender.

CONCLUSION

This study demonstrates that the adverse effects of dipyridamole were generally minimal and its duration was acceptable for clinical usage.

Effect of Dipyridamole Injected for Myocardial Perfusion Imaging on Blood Glucose Concentration; A Preliminary Study

INTRODUCTION

Dipyridamole inhibits adenosine reuptake and increases cyclic Adenosine Monophosphate (cAMP) levels in platelets, erythrocytes and endothelial cells, all of which influence blood glucose. Acute hyperglycaemia reduces endothelium-dependent vasodilation and suppresses coronary microcirculation; which, in theory, can alter the outcome of a radionuclide scan.

AIM

The present study was conducted with the aim to investigate the changes in blood glucose level of patients receiving dipyridamole for cardiac scan.

MATERIALS AND METHODS

A total of 293 patients (85 men and 208 women, age: 60.59±10.43 years) were included in the study. Fasting Blood Glucose (FBG) was measured before and 8 min after dipyridamole (0.568 mg/kg) injection during myocardial perfusion imaging. The data in different groups were analysed by paired t-test.

RESULTS

There was not a significant difference between first (106.89 ± 19.21mg/dL) and second (107.98 ± 17.57 mg/dL) FBG measurements (p= 0.293). However, when the patients were grouped based on the quartiles of first measurement, there was an increase in FBG following dipyridamole injection in the first quartile (mean difference: 7.15±21.27 mg/dL, p<0.01); in contrast, FBG levels showed a significant decrease after dipyridamole administration in the 4(th) quartile (mean difference: -9.53±18.20 mg/dL, p<0.001). The differences in 2(nd) and 3(rd) quartiles were negligible. The patients were divided into normal, ischemic and fixed lesions based on the outcome of scans, then the possible correlation of dipyridamole-induced FBG alteration and scan results were investigated. There were no significant difference between the FBG values before and after dipyridamole injection and the final outcome of scan.

CONCLUSION

The effects of dipyridamole on blood glucose highly depend on the initial blood glucose level.

New concept of myocardial longitudinal strain reserve assessed by a dipyridamole infusion using 2D-strain echocardiography: the impact of diabetes and age, and the prognostic value

AIMS

Although dipyridamole is a widely used pharmacological stress agent, the direct effects on myocardium are not entirely known. Diabetic cardiomyopathy can be investigated by 2D-strain echocardiography. The aim of this study was to assess myocardial functional reserve after dipyridamole infusion using speckle-tracking echocardiography.

METHODS

Seventy-five patients referred for dipyridamole stress myocardial perfusion gated SPECT (MPGS) were examined by echocardiography to assess a new concept of longitudinal strain reserve (LSR) and longitudinal strain rate reserve (LSRR) respectively defined by the differences of global longitudinal strain (GLS) and longitudinal strain rate between peak stress after dipyridamole and rest. Twelve patients with myocardial ischemia were excluded on the basis of MPGS as gold standard.

RESULTS

Mean LSR was -2.28±2.19% and was more important in the 28 (44%) diabetic patients (-3.27±1.93%; p=0.001). After multivariate analyses, only diabetes improved LSR (p=0.011) after dipyridamole infusion and was not associated with glycaemic control (p=0.21), insulin therapy (p=0.46) or duration of the disease (p=0.80). Conversely, age (p=0.002) remained associated with a decrease in LSR. LSSR was also correlated to age (p=0.005). Patients with a LSR<0% have a better survival after 15 months (log-rank p=0.0012).

CONCLUSION

LSR explored by 2D speckle-tracking echocardiography after dipyridamole infusion is a simple and new concept that provides new insights into the impact of diabetes and age on the myocardium with a potential prognostic value.

Potential role of endogenous adenosine in ticagrelor-induced dyspnea

Ticagrelor, a recently approved platelet antagonist indicated for the reduction of thrombotic cardiovascular events in patients with acute coronary syndrome (ACS), has been reported to cause dyspnea in more than 13% of patients. Dyspnea is not a clinically relevant adverse event with other medications indicated for ACS. One suggested mechanism of ticagrelor-induced dyspnea involves an increase in systemic adenosine concentrations through adenosine deaminase inhibition. Dyspnea, a subjective finding resulting from physiologic and sensory mechanisms, may be a consequence of increased systemic adenosine concentrations, leading to amplified and prolonged receptor activity. Current literature suggests, however, that pulmonary status is not compromised, with no reduction of efficacy seen in patients with ticagrelor-induced dyspnea, thus allowing clinicians to continue therapy without reservation. Still, patients with a history of asthma and chronic obstructive pulmonary disease may be more susceptible to ticagrelor-induced dyspnea, potentially leading to nonadherence and exacerbations of morbidity. Therefore, it is paramount that health care providers continually monitor these patients with the aims of maintaining medication therapy adherence and providing relevant options if dyspnea becomes intolerable.

The utility and prognostic value of dipyridamole technetium-99m sestamibi myocardial perfusion imaging SPECT in predicting perioperative cardiac events following non-cardiac surgery

OBJECTIVE

A perioperative cardiac events is one of the most important medical concerns for both surgeons and patients. The purpose of the current study was to determine the prognostic value of myocardial perfusion imaging (MPI), using dipyridamole 99m Tc-MIBI, for the prediction of perioperative cardiac events.

MATERIALS AND METHODS

This study included 253 patients who were candidates for non-cardiac elective surgery and underwent scanning with dipyridamole 99m Tc-MIBI. Based on normal or abnormal MPI, patients were divided into two groups and all preoperative cardiac events were recorded. Risk factors, including diabetes mellitus, dyslipidemia, hypertension, smoking and age ≥70 years, were compared between patients with normal and abnormal MPI and, also, in patients with or without cardiac events.

RESULTS

There were 197 patients with normal and 56 patients with abnormal MPI. In total, 14 patients had perioperative cardiac events, which included myocardial infarction (MI), hypotension, arrhythmia and death; of the 14 patients with perioperative cardiac events, 12 had abnormal and two had normal MPI. There were statistically meaningful differences between the two groups (p<0.001). Based on these findings, we determined that MPI had a sensitivity of 85.7%, a specificity of 81.6%, an accuracy of 81.8%, a positive predictive value of 21.4 % and a negative predictive value of 98.9%.

CONCLUSION

The incidence of perioperative cardiac events is higher in patients with abnormal MPI. Dipyridamole 99m Tc-MIBI myocardial perfusion imaging can accurately detect the preoperative cardiac risk of patients undergoing major non-cardiac surgery. Based on these findings, the occurrence of perioperative cardiac events in patients with abnormal MPI should be considered, especially in the older age population (age ≥70).

Factors Influencing Non-cardiac Side Effects of Dipyridamole When Used for Myocardial Perfusion Stress Testing

PURPOSE

This study evaluates whether patient demographic information can be used to predict the non-cardiac side effects experienced during myocardial perfusion imaging (MPI) procedures using dipyridamole.

BACKGROUND

Heart disease is a major cause of death in the industrialized world. MPI of coronary blood flow using radiopharmaceuticals is frequently used to assess coronary artery disease. Pharmacological methods can be used to increase coronary blood flow with vasodilators such as dipyridamole or adenosine, or inotropic and chronotropic agents such as dobutamine or arbutamine. The side effects of these agents are recognized, but little is known about the factors that influence their frequency and severity.

METHODS

One hundred and nineteen patients scheduled for myocardial perfusion pharmacological stress testing using dipyridamole participated in the study. Patient demographic data, which included age, sex, body mass index (BMI), diabetic status, smoker status, and daily aspirin usage, were collected before the start of the procedure. Patients underwent a 1-day rest and stress MPI procedure. The radiopharmaceuticals used were ^99mTc-Myoview or ²⁰¹Tl. The pharmacological stress procedure used dipyridamole injections based on body weight. Aminophylline was injected at the end of the stress session. Gated single photon emission computed tomography was performed for both rest and stress images. Once the patients completed the procedure, they were given a questionnaire that asked them to report the severity of any side effects experienced from the dipyridamole. Specific data types determined the statistical test best suited for analysis. The Chi-square test was used to evaluate the nominal scale data (sex, diabetic status, aspirin usage, and smoker status), Mann-Whitney test was used to compare nominal scale data and ordinal scale data (side effect severity), Student's t-test r was used for ratio scale data (age, BMI, and percent of population), and multiple linear regression and multiple logistic regression tests were used to evaluate multiple variables.

RESULTS

A total of 119 patients were surveyed (58 male, 61 female). The average age was 67.7 years (10.7 year standard deviation). There were no statistically significant differences in the male and female demographics except for daily aspirin usage (more common with males). Headaches were the most common side effect (50% of all patients), followed by dizziness (26%), flushing (24%), chest pain (19%), and nausea (18%). Correlations were found between patients experiencing no side effects with age (r = -0.607) and sex (P = .034); headaches with age (r = -0.706) and BMI (r = 0.464); chest pain with diabetic status (P = .017); dizziness with diabetic status (P = .039); and nausea with age (r = -0.612).

CONCLUSION

Side effects of dipyridamole are generally known, but the factors influencing incidence and severity are not. This study has shown that patient demographic information normally gathered before MPI procedures can help determine the frequency and severity of some side effects. Providing more accurate information to a patient on the possible side effects could help reduce patient anxiety and improve patient cooperation.

The association of rate pressure product (RPP) and myocardial perfusion imaging (MPI) findings: a preliminary study

Introduction: The product of heart rate and systolic blood pressure, termed as rate-pressure product (RPP), is a very reliable indicator of myocardial oxygen demand and is widely used clinically. There have been previous attempts to describe the relationship between RPP and the onset of pain in angina pectoris. The current study aimed to evaluate the association between RPP results and scan findings.

Materials and methods: In total, 497 patients with suspected coronary artery disease (CAD) underwent gated, single-photon emission computed tomography (SPECT) imaging with dipyridamole, exercise, or dobutamine stress, and were included in this study. Baseline and maximum heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and electrocardiogram (ECG) results were recorded. The rate-pressure product (RPP) was calculated as the product of heart rate and systolic arterial pressure for both baseline and maximum measures. The difference between the RPP max and the basal RPP is known as the RPP reserve. Researchers also obtained semi-quantitative analyses of myocardial perfusion imaging (MPI), using gated software, demographic information, risk factors of CAD, and pretest likelihoods of CAD using nomograms.

Result: Four hundred and ninety-seven cases, including 426 patients with dipyridamole stress, 59 with exercise stress, and 12 with dobutamine stress, underwent myocardial perfusion imaging. Scan results were positive in 194 (45.5%) and negative in 232 (54.5%) patients with dipyridamole stress. In patients with exercise stress, the scan was positive in 24 (40.7%) cases and negative in 35 (59.3%) cases. In dobutamine stressed patients, the scan was positive in 6 (50%) cases and negative in the 6 remaining cases. Dipyridamole stress resulted in a significant difference between HR at rest and at maximum (28.95 ± 24.53, p-value<0.0001), between systolic BP at rest and maximum (6.75 ± 12.50, p-value<0.0001) and between diastolic BP at rest and maximum (1.45 ± 5.80; p-value<0.0001). There was a significant correlation between sum stress scores (SSS) and reserved RPP (r= −0.12, p-value<0.001) which, in dipyridamole patients, was r=−0.18, p-value=0.0001). In addition, there was a significant association between reserved RPP and risk of CAD (p-value<0.001). In the patients with dipyridamole stress, the ejection fraction (EF) change (odds ratio =0.92; 95% CI: 0.86-0.98; p=0.01), reserve RPP (odds ratio =1.00; 95% CI: 1.00-1.00; p=0.04), risk of CAD (odds ratio =5.80; 95% CI: 3.21-10.50; p<0.0001) and age (odds ratio =0.94; 95% CI: 0.89-0.98; p=0.01) were associated significantly with MPI results, using multiple logistic regressions.

Conclusion. The study demonstrated that RPP is associated with MPI findings using gated SPECT imaging with dipyridamole stress. However, to confirm this preliminary result, further studies are mandatory.

Pharmacological stress cardiovascular magnetic resonance

Over the past decade, cardiovascular magnetic resonance (CMR) has evolved into a cardiac stress testing modality that can be used to diagnose myocardial ischemia using intravenous dobutamine or vasodilator perfusion agents such as adenosine or dipyridamole. Because CMR produces high-resolution tomographic images of the human heart in multiple imaging planes, it has become a highly attractive noninvasive testing modality for those suspected of having myocardial ischemia. The purpose of this article is to review the clinical, diagnostic, and prognostic utility of stress CMR testing for patients with (or suspected of having) coronary artery disease.

Identification of left ventricular myocardial ischemia and cardiac prognosis with cardiovascular magnetic resonance: updates from 2008 to 2010

Noninvasive imaging modalities are often used to manage patients with cardiovascular disease. Cardiovascular magnetic resonance (CMR) is increasingly used for diagnosing and evaluating myocardial ischemia and viability; moreover, stress CMR study results can be used to determine cardiac prognosis. In this article, we review recently published material regarding the performance of stress testing with CMR including a brief update regarding techniques, stress agents, diagnostic accuracy, prognosis, economic implications, and ongoing trials and future developments.