Introduction: A dipyridamole induced stress myocardial perfusion scintigraphy with Tc-99m Sestamibi is utilized for diagnosing coronary artery diseases. The use of dipyridamole as form of pharmacologic stressor has expected hemodynamic changes. Objective: The objective of this study was to determine the association of these changes with the scan parameters in patients with suspected coronary artery disease (CAD). Methodology: A total of 101 patients, with suspected CAD, who underwent a dipyridamole-induced stress myocardial perfusion scintigraphy using Tc-99m Sestamibi from January 2019 to March 2020 were included in this study. The patient databases, monitoring sheets, and scan results were reviewed . Results: The blood pressure responses had no significant association with the scan parameters and results. The normal (> 1.2) and abnormal (<1.2) heart rate ratios (HRR), which is the peak HR/baseline HR, likewise had no significant association with the scan results. However, in terms of the median HRR, the higher ratio of 1.29 (normal scan results) against the ratio of 1.25 (abnormal scan results) was determined to be significant (p-value of 0.032). The HRR also had a direct and indirect weak correlation with stress and rest Left Ventricular Ejection Fraction (LVEF) values (p-values of 0.09 and 0.011) and Summed Rest Score (p-value of 0.007), respectively. For the 12-L ECG, only the baseline normal (P-value of 0.018) and infarct findings (p-value of 0.017) were similarly associated with normal and abnormal scan results, respectively. Conclusion For patients with suspected CAD, the higher HRRs and baseline 12-L ECG of normal and infarct findings relates to the expected scan result. For scan parameters, the higher HRRs were also correlated with higher stress and rest LVEF values, and normal SRS, albeit a weak correlation. Notably, the blood pressure and post-infusion 12-L ECG changes had no significant association. In summary, the higher HRRs indicates normal scan results, normal SRS, and better LVEF values which increases the diagnostic confidence in the interpretation and management, especially in some equivocal cases.
Dipyridamole ; Myocardial perfusion scintigraphy

PURPOSE: Phosphodiesterase (PDE) inhibitors increase matrix metalloproteinase (MMP) production by inhibiting re-uptake of adenosine and may potentiate nitric oxide (NO) activity. This study was performed to investigate the effects and mechanisms of PDE inhibitors on trabecular outflow in cultured human trabecular meshwork cells (HTMCs). METHODS: Primary HTMC cultures were exposed to 0, 20, and 50 µM dipyridamole (DPD) or theophylline (TPN). Permeability through the HTMC monolayer was assessed using carboxyfluorescein. The production of NO was assessed using the Griess assay and MMP-2 levels were measured via Western blotting. RESULTS: DPD significantly increased permeability accompanied with increased nitrite concentration and MMP-2 levels (all p < 0.05). TPN increased nitrite but did not affect permeability or MMP-2 levels significantly (p > 0.05). When treated with DPD and TPN together, both permeability and nitrite production were increased; however, MMP-2 levels showed no difference compared to DPD exposure alone (p > 0.05). CONCLUSIONS: DPD increased trabecular permeability accompanied with increased nitrite production and MMP-2 levels. PDE inhibitors may increase trabecular outflow by increasing MMP-2 levels and by potentiating NO activity through cyclic GMP in HTMC.
Adenosine ; Blotting, Western ; Cyclic GMP ; Dipyridamole ; Humans ; Matrix Metalloproteinases ; Nitric Oxide ; Permeability ; Phosphodiesterase Inhibitors ; Theophylline ; Trabecular Meshwork

OBJECTIVE: To provide information about the effectiveness and safety of Ginkgo Leaf Extract and Dipyridamole Injection (GD) as one adjuvant therapy for treating angina pectoris (AP) and to evaluate the relevant randomized controlled trials (RCTs) with meta-analysis. METHODS: RCTs concerning AP treated by GD were searched in China Biology Medicine Disc (SinoMed), PubMed, the China National Knowledge Infrastructure Database (CNKI), the Chinese Scientifific Journals Database (VIP), Wanfang Database, Embase, and the Cochrane Library, from inception to February, 2017. The Cochrane Risk Assessment Tool was adopted to assess the methodological quality of the RCTs. The Review Manager 5.3 software was utilized to conduct the meta-analysis. RESULTS: A total of 41 RCTs involving 4,462 patients were included in the meta-analysis. The results indicated that the combined use of GD and Western medicine (WM) against AP was associated with a higher total effective rate [risk ratio (RR)=1.25, 95% confifidence interval (CI): 1.21-1.29, P<0.01], total effective rate of electrocardiogram (RR=1.29, 95% CI: 1.21-1.36, P<0.01). Additional, GD combined with WM could decrease the level of plasma viscosity [mean difference (MD)=-0.56, 95% CI:-0,81 to-0.30, P<0.01], fifibrinogen [MD=-1.02, 95% CI:-1.50 to-0.54, P<0.01], whole blood low shear viscosity [MD=-2.27, 95% CI:-3.04 to-1.49, P<0.01], and whole blood high shear viscosity (MD=-0.90, 95% CI: 1.37 to-0.44, P<0.01). CONCLUSIONS Comparing with receiving WM only, the combine use of GD and WM was associated with a better curative effect for patients with AP. Nevertheless, limited by the methodological quality of included RCTs more large-sample, multi-center RCTs were needed to confifirm our fifindings and provide further evidence for the clinical utility of GD.
Angina Pectoris ; drug therapy ; Blood Viscosity ; drug effects ; Dipyridamole ; administration & dosage ; adverse effects ; Drug Combinations ; Humans ; Injections ; Plant Extracts ; administration & dosage ; adverse effects ; Randomized Controlled Trials as Topic ; Western World

Background: Left ventricular (LV) eccentricity index (EI) is a measure of the LV shapre obtained with a commonly used quantitative software for mycardial perfusion scintigraphy (MPS). However, there are limited studies evaluating its correlation with other MPS parameters, for which this study was done. Methodology: All patients who underwent 99mTc-sestamibi stress MPS from 2013 to 2015 were screened. A total of 353 patients, 228 (65%) males and 125 (35%) females, met the inclusion criteria. One hundred twenty-nine (37%) underwent exercise stress while 224 (63%) were given dipyridamole. Spearman's rho correlation was used to determine the correlation of rest and post-stress EI with the other study variables. Results: Among males, rest EI showed negative correlation with summed stress score (SSS) (rs = -0.182, p<0.005), transient ischemic dilatation (TID) (rs=-0.172, p=0.009), rest LV end-diastolic volume (EDV) (rs=-0.291, p < 0.001), rest LV end-systolic volume (ESV)(rs=-0.316, p < 0.001), p0-st-streSS LVEDV (rs= -0.218, p < 0.001), and post-stress LVESV (rs= -0.331, p < 0.001). There was positive correlation with rest LV ejection fraction (EF) (rs= 0.291,p < 0.001) and post-stress LVEF (r5 = 0. 336, p < 0. 001). No sig11ifico11t relationship with any of the MPS parameters was observed among females. For both exercise and dipyridamole groups. EI exhibited negative correlation with SSS, and rest and stress LVESV; and positive cotrelation with rest and post-stress LVEF. Significant relationship with rest and stress LVEDV was only observed in the dipyridamole group. Conclusions This study shows that EI is correlated with most, if not all, of the MPS parameters with different levels of association depending on the patient's sex and the type of stress employed. More spherical LV is correlated with more severe perfusion defects, larger LV cavity volumes and poorere LV systolic function.
Technetium Tc 99m Sestamibi ; Dipyridamole

We performed real-time myocardial contrast echocardiography on a patient with cardiac amyloidosis and previous normal coronary angiography presenting with atypical chest pain to assess myocardial blood flow reserve (MBFR). Myocardial contrast echocardiography was performed and flash microbubble destruction and replenishment analysis was used to calculate myocardial blood flow. Dipyridamole was used to achieve hyperemia. MBFR was derived from the ratio of peak myocardial blood flow at hyperemia and rest. The results show a marked reduction in MBFR in our patient. Previous reports of luminal obstruction of intramyocardial rather than epicardial vessels by amyloid deposition may be causing microvascular dysfunction.
Amyloidosis* ; Chest Pain ; Coronary Angiography ; Dipyridamole ; Echocardiography ; Humans ; Hyperemia ; Microbubbles ; Phenobarbital ; Plaque, Amyloid

OBJECTIVES: Impairment of coronary flow reserve (CFR) precedes preclinical atherosclerosis. However, data are lacking regarding its prognostic utility using SPECT imaging. Thus, this study aimed to determine the clinical utility of CFR by sestamibi imaging in predicting future cardiac events in patients with normal and abnormal myocardial perfusion scan (MPS).

METHODS: This was a prospective cohort study of 54 consecutive adult patients with suspected coronary artery disease referred to Nuclear Medicine Division, Philippine Heart Center for dipyridamole technetium-99m sestamibi SPECT MPS from August 2012 to September 2013. Patients with normal (summed stress score, SSS <3) and abnormal (SSS> 4) perfusion scans were further subdivided based on their CFR whether normal (CFR> 2) or abnormal (CFR < 2). Using a validated 2-day protocol, estimated CFR was computed from the ratio of dipyridamole myocardial blood flow (MBE) to resting MBF. MBF was obtained by dividing the global myocardial counts with the arterial input function. Global myocardial counts were derived from the average of the mean counts/pixel of two representative short-axis tomograms at the mediobasal and medioapical views. For the arterial input function, first-pass analysis of the pulmonary artery was performed to generate the time-activity curve (TAC). The mean counts/pixel of the area under the curve represented the input junction. Patients were monitored for major adverse cardiac events (MACE) through phone contact by patient and by review of hospital and physician's record six months after scintigraphy (mean follow-up 9+3 months). Major cardiac events include cardiac death, acute coronary syndrome, unstable angina, and revascularization.

RESULTS: A prospective cohort of 54 consecutive patients with no known CAD, were enrolled in the study. Abnormal MPI revealed significantly lower CFR (1.64 + 0.47 vs. 1.19 + 0.36, p=0.005). The annual cardiac event rate increased in the presence of reduced CFR in spite of a normal MPI (from 0% to 6.9%), and was even higher when both MPI and CFR were abnormal (from 0% to 34.7%). In Kaplan-Meier analysis, patients with abnormal perfusion revealed-significantly higher incidence of cardiac events compared with normal perfusion (chi-square 4.93, p=0.027). There was a trend towards increased incidence of cardiac events in patients with abnormal CFR; however, this did not reach statistical significance (chi-square 0.61, p=0.434).

CONCLUSION: A low CFR was associated with an increased incidence of MACE, particularly in the presence of abnormal perfusion findings.

Human ; Male ; Female ; Adult ; Technetium Tc 99m Sestamibi ; Dipyridamole ; Acute Coronary Syndrome ; Kaplan-meier Estimate ; Heart ; Angina, Unstable ; Myocardium

OBJECTIVES: Impairment of coronary flow reserve (CFR) precedes preclinical atherosclerosis. However, data are lacking regarding its prognostic utility using SPECT imaging. Thus, this study aimed to determine the clinical utility of CFR by sestamibi imaging in predicting future cardiac events in patients with normal and abnormal myocardial perfusion scan (MPS).

METHODS: This was a prospective cohort study of 54 consecutive adult patients with suspected coronary artery disease referred to Nuclear Medicine Division, Philippine Heart Center for dipyridamole technetium-99m sestamibi SPECT MPS from August 2012 to September 2013. Patients with normal (summed stress score, SSS <3) and abnormal (SSS> 4) perfusion scans were further subdivided based on their CFR whether normal (CFR> 2) or abnormal (CFR < 2). Using a validated 2-day protocol, estimated CFR was computed from the ratio of dipyridamole myocardial blood flow (MBE) to resting MBF. MBF was obtained by dividing the global myocardial counts with the arterial input function. Global myocardial counts were derived from the average of the mean counts/pixel of two representative short-axis tomograms at the mediobasal and medioapical views. For the arterial input function, first-pass analysis of the pulmonary artery was performed to generate the time-activity curve (TAC). The mean counts/pixel of the area under the curve represented the input junction. Patients were monitored for major adverse cardiac events (MACE) through phone contact by patient and by review of hospital and physician's record six months after scintigraphy (mean follow-up 9+3 months). Major cardiac events include cardiac death, acute coronary syndrome, unstable angina, and revascularization.

RESULTS: A prospective cohort of 54 consecutive patients with no known CAD, were enrolled in the study. Abnormal MPI revealed significantly lower CFR (1.64 + 0.47 vs. 1.19 + 0.36, p=0.005). The annual cardiac event rate increased in the presence of reduced CFR in spite of a normal MPI (from 0% to 6.9%), and was even higher when both MPI and CFR were abnormal (from 0% to 34.7%). In Kaplan-Meier analysis, patients with abnormal perfusion revealed-significantly higher incidence of cardiac events compared with normal perfusion (chi-square 4.93, p=0.027). There was a trend towards increased incidence of cardiac events in patients with abnormal CFR; however, this did not reach statistical significance (chi-square 0.61, p=0.434).

CONCLUSION: A low CFR was associated with an increased incidence of MACE, particularly in the presence of abnormal perfusion findings.

Human ; Male ; Female ; Adult ; Technetium Tc 99m Sestamibi ; Dipyridamole ; Acute Coronary Syndrome ; Kaplan-meier Estimate ; Heart ; Angina, Unstable ; Myocardium

Aged ; Aged, 80 and over ; Anticoagulants ; therapeutic use ; Aspirin ; therapeutic use ; Atrial Fibrillation ; complications ; drug therapy ; Brain Ischemia ; etiology ; prevention & control ; Dabigatran ; therapeutic use ; Dipyridamole ; therapeutic use ; Female ; Guideline Adherence ; statistics & numerical data ; Humans ; Male ; Middle Aged ; Platelet Aggregation Inhibitors ; therapeutic use ; Practice Guidelines as Topic ; Primary Prevention ; statistics & numerical data ; Pyrazoles ; therapeutic use ; Pyridones ; therapeutic use ; Rivaroxaban ; therapeutic use ; Stroke ; etiology ; prevention & control ; Ticlopidine ; analogs & derivatives ; therapeutic use ; Warfarin ; therapeutic use

OBJECTIVETo investigate the effect of the anticoagulants on PRP quality, so as to clarify the appropriate anticoagulant used in PRP production.

METHODSThe microstructure change of platelets collected via heparin, citrate, acid citrate dextrose (ACD) and citrate-theophylline-adenosine-dipyridamole ( CTAD) was observed by TEM following time course. The extent of spontaneous activation of platelets in four groups was detected by measuring sP-selectin in plasma. The TGF-β1 release amount of activated PRP of four groups was measured.

RESULTSCTAD is superior to other anticoagulants in maintaining the integrity of platelet structures for a long time and preventing platelet spontaneous activation. ACD slightly surpassed heparin and citrate in above two aspects. ACD-PRP and CTAD-PRP released significantly more TGF-β1 compared with heparin and citrate.

CONCLUSIONSThe PRP quality and biological effects were strongly associated with the type of Anticoagulants. ACD and CTAD are optimal anticoagulants in PRP production for they can maintain platelet viability at a high level.

Adenosine ; pharmacology ; Anticoagulants ; pharmacology ; Blood Platelets ; drug effects ; physiology ; Citrates ; pharmacology ; Citric Acid ; pharmacology ; Dipyridamole ; pharmacology ; Drug Combinations ; Glucose ; analogs & derivatives ; pharmacology ; Heparin ; pharmacology ; Platelet Activation ; drug effects ; Platelet-Rich Plasma ; Theophylline ; pharmacology ; Transforming Growth Factor beta1 ; metabolism

BACKGROUND: Blunting of coronary flow reserve (CFR) may precede overt ischemia. The study aimed to correlate CFR with perfusion findings and risk factors for coronary artery disease (CAD).
METHODS: Fifty-four consecutive patients underwent dipyridamole-rest technetium-99m sestamibi single photon emission computed tomography (SPECT) on two separate days. CFR was computed as the quotient of myocardial blood flow (MBF= global tissue perfusion divided by arterial input function) at stress and at rest.
RESULTS: CFR was significantly lower in patients with abnormal perfusion vs normals (p=0.005). Reduced CFR was noted in 83% of patients with normal SPECT. Lower CFR was seen in hypertensive patients with left ventricular hypertrophy (LVH) compared to those without LVH (p=0.029); likewise in DM vs no DM (p=0.121). Independent predictors of reduced CFR were age and extent of ischemia.
CONCLUSION: Abnormal perfusion is associated with reduced CFR. In those with normal perfusion, there is a high prevalence of reduced CFR, which may be attributed to the presence of risk factors for CAD and LVH.

Human ; Male ; Female ; Arteries ; Coronary Artery Disease ; Dipyridamole ; Hypertrophy, Left Ventricular ; Risk Factors ; Technetium Tc 99m Sestamibi ; Tomography, Emission-computed, Single-photon