Pharmacologic Stress Testing Research Articles

Association Between High-Sensitivity Cardiac Troponin Levels and Myocardial Ischemia During Mental Stress and Conventional Stress

ObjectivesThis study sought to investigate whether patients with mental stress–induced myocardial ischemia will have high resting and post–mental stress high-sensitivity cardiac troponin I (hs-cTnI). BackgroundHs-cTnI is a marker of myocardial necrosis, and its elevated levels are associated with adverse outcomes. Hs-cTnI levels may increase with exercise in patients with coronary artery disease. Mental stress–induced myocardial ischemia is also linked to adverse outcomes. MethodsIn this study, 587 patients with stable coronary artery disease underwent technetium Tc 99m sestamibi–single-photon emission tomography myocardial perfusion imaging during mental stress testing using a public speaking task and during conventional (pharmacological/exercise) stress testing as a control condition. Ischemia was defined as new/worsening impairment in myocardial perfusion using a 17-segment model. ResultsThe median hs-cTnI resting level was 4.3 (interquartile range [IQR]: 2.9 to 7.3) pg/ml. Overall, 16% and 34.8% of patients developed myocardial ischemia during mental and conventional stress, respectively. Compared with those without ischemia, median resting hs-cTnI levels were higher in patients who developed ischemia either during mental stress (5.9 [IQR: 3.9 to 8.3] pg/ml vs. 4.1 [IQR: 2.7 to 7.0] pg/ml; p < 0.001) or during conventional stress (5.4 [IQR: 3.9 to 9.3] pg/ml vs. 3.9 [IQR: 2.5 to 6.5] pg/ml; p < 0.001). Patients with high hs-cTnI (cutoff of 4.6 pg/ml for men and 3.9 pg/ml for women) had greater odds of developing mental (odds ratio [OR]: 2.4; 95% confidence interval [CI]: 1.5 to 3.9; p < 0.001) and conventional (OR: 2.4; 95% CI: 1.7 to 3.4; p < 0.001) stress-induced ischemia. Although there was a significant increase in 45-min post–treadmill exercise hs-cTnI levels in those who developed ischemia, there was no significant increase after mental or pharmacological stress test. ConclusionsIn patients with coronary artery disease, myocardial ischemia during either mental stress or conventional stress is associated with higher resting levels of hs-cTnI. This suggests that hs-cTnI elevation is an indicator of chronic ischemic burden experienced during everyday life. Whether elevated hs-cTnI levels are an indicator of adverse prognosis beyond inducible ischemia or whether it is amenable to intervention requires further investigation.

Abstract P326: Myocardial Ischemia and Mobilization of Circulating Progenitor Cells

Background: Circulating progenitor cells (CPCs) are involved in vascular repair and regeneration. Low levels of CPCs in patients with CAD have been linked to adverse cardiovascular outcomes. The response of CPCs to transient myocardial ischemia in patients with CAD has not been studied before. We aimed to investigate the CPC response to exercise provoked myocardial ischemia (demand ischemia), and compare it to myocardial ischemia detected during pharmacological stress test (flow mismatch). Methods: 570 patients with stable CAD underwent 99mTc sestamibi myocardial perfusion imaging during exercise (69%), or pharmacological stress (31%). myocardial ischemia was defined as a new or worsening impairment in myocardial perfusion using a 17-segment model. CD34+ CPCs were enumerated by flow cytometry at rest and 30 min after stress testing. The change in CPC count was compared between patients with and without myocardial ischemia using mixed linear models. Results: Mean age was 63±9 years, 76% males, 36% with previous myocardial infarction. The incidence of myocardial ischemia was 31% and 41% during exercise and pharmacological stress test, respectively. No difference was observed in resting CPC between patients undergoing exercise vs pharmacological stress test, nor between patients with or without myocardial ischemia. However, patients who developed myocardial ischemia during exercise stress had a significant decrease in CPC with stress in comparison to those without myocardial ischemia (-12% vs 4%, respectively, p=0.006). Furthermore, the change in CPCs was inversely correlated with the magnitude of myocardial ischemia (R=-0.13, p=0.023), suggesting a greater CPC reduction with larger ischemic burden. These findings remained significant even after adjustment for age, gender, race, BMI, previous myocardial infarction, resting levels of CPCs and hematocrit change with stress. No difference was observed in CPC response to pharmacological stress test (change of -1% vs 3%, for patients with and without myocardial ischemia, respectively, p=0.96). Conclusion: Exercise stress-induced myocardial ischemia is associated with a decrease in CPC counts, likely due to increased homing of stem cells to the ischemic myocardium. Whether the extent of CPC uptake has prognostic implication, or whether the CPC response can be altered with intervention needs further investigation.

Abstract 119: Comparison of Gated SPECT, Echocardiography and Angiography Ejection Fractions

Background: Gated stress studies with Thallium previously suggested that SPECT overestimated the ejection fraction obtained with other modalities, limiting its use. Objective: To compare ejection fractions (EF) obtained from post pharmacologic stress gated SPECT using Technicium99m with EFs estimated by transthoracic echocardiography (TTE) or cardiac catheterization (angio). Methods: From a university-based outpatient stress lab, 502 stress tests performed over 14 months were reviewed; 126 gated pharmacologic stress tests were analyzed. Contemporaneous TTEs were available in 114, and angios in 26 of the studies. The stress nuclear protocols included a slow walk and the stress agent was regadenoson in the majority of the studies. Mean EF reported from the post-stress gated SPECT, TTEs, and angios were tested with ANOVA. The absolute variance in EF between each two contemporaneous groups was averaged and compared using a 2-tailed student t-test to the other groups. Results: The mean EFs obtained from SPECT, TTE and angio were 64 ± 12%, 58 ± 9% and 53 ± 6% respectively (P &lt; 0.01). The absolute variance in SPECT-TTE and SPECT-angio were 9.2 ± 6.4% and 10.3 ± 7.7% respectively (P &lt; 0.05 vs TTE-angio); TTE-angio absolute variance was 5.6 ± 4.8%. Discussion: Studies have conflicted with regards to reliability of gated SPECT-derived left ventricular volumes and ejection fractions. Although lack of correlation has been suggested, overestimation of ejection fraction has also been described. In this study we found a tendency for SPECT to overestimate the ejection fraction in post-stress gated studies compared with echocardiography and cath. Although several factors may have contributed to this observation, it is possible that the SPECT EF is augmented by the vasodilator effect of the stress pharmacologic agent. Further studies are needed to better qualify these findings. Meanwhile, given the importance of accurate quantification of a resting ejection fraction, especially as it relates evaluation of significant of valvular abnormalities or device therapy in heart failure, reliance on a SPECT-derived ejection fraction may cause undue delay in therapy.

Myocardial perfusion SPECT 2015 in Germany. Results of the 7th survey.

SummaryAimThe working group Cardiovascular Nuclear Medicine of the German Society of Nuclear Medicine presents the results of the 7th survey of myocardial perfusion SPECT (MPS) of the reporting year 2015.Method268 questionnaires (173 practices [PR], 67 hospitals [HO], 28 university hospitals [UH]) were evaluated. Results of the last survey from 2012 are set in squared brackets.ResultsMPS of 121 939 [105 941] patients were reported. 98 % [95 %] of all MPS were performed with Tc-99m radiopharmaceuticals and 2 % [5 %] with Tl-201. 78 % [79 %] of all patients were studied in PR, 14 % [15 %] in HO, and 8 % [6 %] in UH. A pharmacological stress test was performed in 43 % [39 %] (22 % [24 %] adenosine, 20 % [9 %] regadenoson, 1% [6 %] dipyridamole or dobutamine). Attenuation correction was applied in 25 % [2009: 10 %] of MPS. Gated SPECT was performed in 78 % [70 %] of all rest MPS, in 80 % [73 %] of all stress and in 76 % [67 %] of all stress and rest MPS. 53 % [33 %] of all nuclear medicine departments performed MPS scoring by default, whereas 24 % [41 %] did not apply any quantification. 31 % [26 %] of all departments noticed an increase in their counted MPS and 29 % [29 %] no changes. Data from 89 departments which participated in all surveys showed an increase in MPS count of 11.1 % (PR: 12.2 %, HO: 4.8 %, UH: 18.4 %). 70 % [60 %] of the MPS were requested by ambulatory care cardiologists.ConclusionThe 2015 MPS survey reveals a high-grade adherence of routine MPS practice to current guidelines. The positive trend in MPS performance and number of MPS already observed in 2012 continues. Educational training remains necessary in the field of SPECT scoring.

SINGLE PHOTON EMISSION COMPUTED TOMOGRAPHY IN DIAGNOSTICS OF OBSTRUCTIVE LESION IN CORONARY ARTERIES

Aim. To evaluate the potential of single photon emission computed tomography (SPECT) in diagnostics of obstructive lesion of coronary arteries (CA). Material and methods. The studied group consisted of 107 patients, admitted for diagnostics and treatment in the SRI CICVD during 2012-2015 with former established diagnosis of coronary heart disease (CHD) or hospitalized to rule it out. For hemodynamically significant stenoses, coronary arteriography (CAG) was applied. Data from CAG was compared with SPECT. As a result, four groups were formed: 1 group — with positive results by SPECT and CAG (SPECT“+”/CAG“+”, n=24); 2 group — with positive SPECT and negative CAG (SPECT“+”/CAG“-”, n=6); 3 group — with negative SPECT and positive CAG (SPECT“-”/CAG“+”, n=36); 4 group — negative both SPECT and CAG (SPECT“-”/CAG“-”, n=41). Results. In assessment of the patients with suspected CHD, positive result of pharmacological stress-test in SPECT was revealed in 28% cases, and hemodynamically significant CA lesion was found in 56% of patients. Myocardial infarction in anamnesis predominated in SPECT“+”/CAG“+” (79,2%), SPECT“+”/CAG“-” (83,3%), SPECT“-”/CAG“+” (55,6%) comparing to SPECT“-”/CAG“-” (39%; р=0,007). Also, in the group SPECT“-”/CAG“-” pre-test probability of CHD was the lowest (58%) comparing to other groups — 80,5%; 80,5% and 77% (р=0,002). Hence ejection fraction of the left ventricle was significantly lower in the group of SPECT“+”/CAG“+” (53%; р=0,011). In this group also subocclusion was found in circumflex (29,2%) and right CA (45,8%), respectively, р=0,033 and р=0,054. With the false negative results of SPECT there was association of male gender, former coronary bypass operation, increased cardiac volume. Sensitivity of SPECT in hemodynamically significant CA stenoses diagnostics was 40%, specificity — 87%. Conclusion. The results of current study are important for further elaboration on the approaches to obstructive CHD diagnostics.

Economic Outcomes With Anatomical Versus Functional Diagnostic Testing for Coronary Artery Disease.

Letters20 December 2016Economic Outcomes With Anatomical Versus Functional Diagnostic Testing for Coronary Artery DiseaseWade H. Martin III, MDWade H. Martin III, MDFrom Washington University School of Medicine and the St. Louis Veterans Administration Healthcare System, St. Louis, Missouri.Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/L16-0481 SectionsAboutFull TextPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail TO THE EDITOR:Mark and colleagues' (1) cost analysis of data from PROMISE (PROspective Multicenter Imaging Study for Evaluation of Chest Pain) suggests little or no difference in cost or outcomes with cardiac computed tomography angiography (CTA) versus functional stress testing for assessment of chest pain or other symptoms of coronary artery disease in relatively low-risk patients evaluated in emergency departments. However, this trial and its conclusions have several important caveats.First, whether pharmacologic stress testing legitimately can be termed “functional” is debatable. Truly functional and relevant clinical information, such as exercise capacity; recovery heart rate; and exercise-induced symptoms, dysrhythmias, ...

Abstract 13388: Autonomic Balance And Mental Stress-induced Myocardial Ischemia

Introduction: Although mental stress-induced myocardial ischemia (MSIMI) has been linked to adverse cardiovascular outcomes, its underlying mechanisms remain to be elucidated. We assessed whether autonomic dysfunction was important in precipitating MSIMI with the hypothesis that autonomic function, estimated using heart rate variability (HRV), will be associated with MSIMI. Methods: We examined autonomic function at rest in 168 patients with CAD using the ANSAR method (ANX 3.0, ANSAR Inc. Philadelphia, PA). Sympathetic and parasympathetic tone were assessed using low (LFa) and respiratory (RFa) frequency HRV that was adjusted for respiration using continuous wavelet transform. Sympathovagal balance was calculated as the ratio of LFa/RFa. Patients underwent 99mTc sestamibi myocardial perfusion imaging during both mental stress testing using a public speaking task, and, as a control condition, with conventional (pharmacologic or exercise) stress testing. Ischemia was defined as a new or worsening impairment in myocardial perfusion within each myocardial segment using a 17-segment model. Results: In our population, (age 63 ± 9 years, 70% men), 11% developed MSIMI and 28% developed conventional stress-induced myocardial ischemia (CSIMI). Patients with MSIMI had higher sympathetic tone and increased sympathovagal balance [median (IQR) LFa of 1.1 (0.4-8.2) vs 0.6 (0.3-1.1) bpm2, p=0.017 and LFa/RFa of 1.7 (0.8-3.6) vs 1.0 (0.6-2.0), p=0.02] but not parasympathetic activity [RFa of 0.8 (0.3-2.9) vs 0.5 (0.2-1.3) bpm2, p=0.29] compared to those without MSIMI. Patients with increased LFa/RFa ratio had significantly higher risk of MSIMI [3rd vs 1st tertile OR(95%CI) of 4.4 (1.1 - 17), p=0.03], that remained significant after adjustment for CAD risk factors, beta blockers, rate pressure product and CSIMI. No correlation was found between LFa, RFa or LFa/RFa HRV and CSIMI. Conclusion: Increased resting sympathovagal balance is associated with increased risk of MSIMI but not CSIMI. This suggests that chronic autonomic imbalance with increased symptathetic tone may be an important factor in the pathogenesis of MSIMI, and may have implications on potential therapies.

The Relation of Arm Exercise Peak Heart Rate to Stress Test Results and Outcome.

Arm exercise is an alternative to pharmacologic stress testing for >50% of patients unable to perform treadmill exercise, but no data exist regarding the effect of attained peak arm exercise heart rate on test sensitivity. Thus, the purpose of this investigation was to characterize the relationship of peak arm exercise heart rate responses to abnormal stress test findings, coronary revascularization, and mortality in patients unable to perform leg exercise. From 1997 until 2002, arm cycle ergometer stress tests were performed in 443 consecutive veterans age 64.1 yr (11.0 yr) (mean (SD)), of whom 253 also underwent myocardial perfusion imaging (MPI). Patients were categorized by frequency distributions of quartiles of percentage age-predicted peak heart rate (APPHR), heart rate reserve (HRR), and peak heart rate-systolic blood pressure product (PRPP). Exercise-induced ST-segment depression, abnormal MPI findings, coronary revascularization, and 12.0-yr (1.3 yr) Kaplan-Meier all-cause and cardiovascular mortality plots were then characterized by quartiles of APPHR, HRR, and PRPP. A reduced frequency of abnormal arm exercise ECG results was associated only with the lowest quartile of APPHR (≤69%) and HRR (≤43%), whereas higher frequency of abnormal MPI findings exhibited an inverse relationship trend with lower APPHR (P = 0.10) and HRR (P = 0.12). There was a strong inverse association of APPHR, HRR, and PRPP with all-cause (all P ≤ 0.01) and cardiovascular (P < 0.05) mortality. The frequency of coronary revascularization was unrelated to APPHR or HRR. Arm exercise ECG stress test sensitivity is only reduced at ≤69% APPHR or ≤43% HRR, whereas arm exercise MPI sensitivity and referral for coronary revascularization after arm exercise stress testing are not adversely affected by even a severely blunted peak heart rate. However, both all-cause mortality and cardiovascular mortality are strongly and inversely related to APPHR and HRR.

Feasibility of exercise stress echocardiography for cardiac risk assessment in chronic kidney disease patients prior to renal transplantation.

Pharmacologic stress testing is utilized in preference to exercise stress echocardiography (ESE) for cardiac risk evaluation in potential renal transplant recipients due to the perceived lower feasibility of ESE for achieving adequate workload and target heart rate (THR) in this population. Consecutive patients referred for cardiac risk evaluation prior to potential kidney transplantation were evaluated. All patients attempted ESE before pharmacologic testing was considered. Treadmill ESE utilized BRUCE protocol to maximum capacity. THR was defined as >85% of the maximum predicted heart rate (220-age). Functional capacity was assessed by metabolic equivalents (METs) and the rate pressure product (RPP). Of 535 patients (349 male, age 56±11), 372(70%) reached THR. Mean METs were 10±3 with 531(99%) achieving ≥4METs and 87% ≥7METs. Mean RPP was 25821±5820bpm×mm Hg (83% achieving >20000bpm×mm Hg). On multivariate analysis, independent predictors of failure to reach THR were rate-control medication and diabetes; failure to reach 7METs: females, diabetics, age≥65, and previous cardiac disease; failure to reach RPP>20000: rate-control medication. There were 97% of ESE completed to physiologic endpoints. In unselected potential renal transplant candidates, cardiac assessment by ESE is well tolerated, with 9-in-10 exercising to satisfactory functional capacity. ESE should be considered a feasible alternative to pharmacologic testing in this population.

Effect of Pharmacologic Stress Test Results on Outcomes in Obese versus Nonobese Subjects Referred for Stress Perfusion Echocardiography

Real-time contrast stress echocardiography (RTCSE) permits the simultaneous analysis of myocardial perfusion and wall motion during stress echocardiography, which has resulted in improved coronary artery disease detection. Although several studies have confirmed a protective effect of obesity in coronary artery disease, it is unclear whether this benefit is dependent on the functional significance of the disease. The objective of this study was to compare outcomes in obese versus nonobese subjects referred for pharmacologic RTCSE. A retrospective comparison of wall motion and myocardial perfusion with RTCSE was assessed in 481 obese and 961 nonobese patients matched for age and gender without known coronary artery disease referred for either dobutamine (n=1,056) or dipyridamole (n=386) stress echocardiography at two separate institutions. Outcomes (death or nonfatal infarction) were determined over a median follow-up period of 1,195days. Abnormal myocardial perfusion and/or wall motion was seen in 207 (20%) dobutamine and 61 (16%) dipyridamole studies. Abnormal rates were similar in obese (17%) and nonobese (19%) subjects. Event-free survival was significantly worse only for nonobese subjects referred for dobutamine RTCSE, with obesity (not test result) being an independent predictor of event-free survival on multivariate analysis (P=.001). No protective effect of obesity was observed following dipyridamole RTCSE. Obese subjects in the United States referred for demand stress testing have better outcomes when directly compared with age- and gender-matched nonobese subjects with similar degrees of inducible ischemia.

0005 : Prognostic value of myocardial perfusion SPECT without significant perfusion defect using a dual isotope protocol and a novel CZT camera: interim results of the PROMHETE study

New dedicated cardiac gamma cameras using CZT detectors have shown significant improvement over the Anger camera regarding physical parameters, and their diagnostic performances have been validated in clinical studies. To date, few studies have evaluated the prognostic value of a low to intermediate risk single-photon emission tomography (SPECT) myocardial perfusion imaging (MPI) with these cameras, and only one with a HSDI stress thallium-201/rest Technetium-99m protocol on a CZT camera. The study included patients who had no or minimal perfusion defects (<10% of the LV myocardium) on a HS-DI MPI following a symptom-limited treadmill test or a pharmacological stress testing. These 578 patients were followed for 3.3±0.4 years (95% complete). The main endpoint was the occurrence a hard cardiac event (cardiac death or nonfatal myocardial infarction). 212 patients (37%) underwent exercise stress and 366 (63%) had pharmacological stress (of which 89% had dipyridamole and 11% had dobutamine). Mean summed stress score was 0.95±1.2 [0-5]. During the follow-up period 25 hard cardiac events occurred. Annualized event rate was 1.3%/y. In the subgroup of patients undergoing exercise stress test, annualized event rate was 0.43%/y. Multivariate Cox analysis identified age (HR 1.14 [1.08; 1.20], p<0.0001) and rest LVEF (HR 0.95 [0.92; 0.98], p=0.008) as independent predictors of cardiac death or myocardial infarction. Survival analysis showed that the occurrence of cardiac events was significantly higher in patients who had an altered LVEF compared to patients with a normal LVEF (16% vs. 3.8%, p=0.003). The use of a HS-DI protocol on a CZT camera provides prognostic information, comparable to single-isotope protocols on conventional Anger camera, while reducing imaging time and without increasing the injected activity. The author hereby declares no conflict of interest

Correlation between Transient Ischemic Dilation Index and Endothelin-1 Level in Patients with Type 2 Diabetes Mellitus.

Transient ischemic dilation (TID) is a sensitive and specific marker for detecting the severity and extent of coronary artery disease (CAD), which is closely associated with endothelial dysfunction. TID can be observed on stress-rest myocardial perfusion scan (MPS) due to subendocardial hypoperfusion. Hyperglycemia in type 2 diabetes mellitus (T2DM) could lead to micro- and macrovascular complications and begins with endothelial dysfunction. Endothelin-1 (ET-1), a potent vasocontrictor, increases in endothelial dysfunction. The aim of this study was to examine the correlation between TID index and ET​​-1 levels in T2DM patients without any sign or symptom of cardiovascular complication. An analytic-correlational cross-sectional study was done on T2DM patients who met the inclusion criteria and agreed to participate by signing an informed consent form. The TID index was calculated automatically using standard software provided by the gamma camera GE-Infinia. Stress-rest MPS was done using technetium-99m (99mTc)-tetrofosmin and a pharmacological stress test using adenosine. The ET-1 level was determined by radioimmunoassay. Data distribution was analyzed using the Shapiro-Wilk normality test. The Mann-Whitney test was used to compare the average difference of the variables and Spearman's rank for correlation analysis. A total of 47 subjects consisting of 24 (51%) males and 23 (49%) females were included in this study. The age range was 37-74 years (54.3 ± 8.4). The TID index range was 0.86-1.26 (median = 1.12) and abnormal TID index was found in 23/47 (49%) subjects. ET-1 levels range 8.02-17.91 pg/mL (median = 11.08). The results showed no significant differences in age, ET-1 levels, and TID index based on age and sex (P > 0.05). There was a significant positive correlation between TID index and ET-1 level with r = 0.7 and P < 0.001. There was a positive correlation between TID index and ET-1 plasma level in patients with T2DM.

Validation of a Patient-reported Outcome (PRO) Measure and a Clinician-reported Outcome (CRO) Measure to Assess Satisfaction with Pharmacologic Stress Agents for Single-photon Emission Computed Tomography (SPECT) Myocardial Perfusion Imaging (MPI)

PurposeThe objective of this study was to develop and validate clinician and patient measures of satisfaction for pharmacologic stress agents (PSAs) used in single-photon emission computed tomography myocardial perfusion imaging procedures. MethodsTwo questionnaires were developed: the Clinician Satisfaction and Preference Questionnaire (CSPQ) and the Patient Satisfaction and Preference Questionnaire (PSPQ). Items were developed, and the content validity of the questionnaires was ensured by participants’ involvement in the item generation (5 clinician and 18 patient face-to-face concept elicitation interviews) and item modification phases (5 clinician and 10 patient face-to-face cognitive debriefing interviews). Psychometric validation of the satisfaction component of the questionnaires was conducted in a sample of 9 clinicians and 90 patients. FindingsAfter initial patient interviews and cognitive interviews, two 8-item instruments were developed with each containing an optional PSA preference question. The PSPQ assessed patients’ receptiveness and satisfaction with the PSA that they received. The CSPQ assessed clinicians’ satisfaction with the time and ease of PSA preparation, administration, and monitoring of the PSA. The optional preference question in both instruments assesses preference among PSAs. In a multicenter observational study of 88 patients and 9 clinicians, the PSPQ Preparation and Reaction to Agent scales elicited reliability coefficients of 0.90 and 0.87, respectively. In addition, the test-retest reliability was acceptable for all PSPQ scales (intraclass correlation coefficient range, 0.73–0.86). Concurrent validity with the Treatment Satisfaction Questionnaire for Medication (TSQM) indicates low-to-moderate correlations between the Effectiveness, Convenience, and Global Satisfaction scales of the TSQM with the PSPQ Satisfaction with Administration, Satisfaction with Effects, and Overall Satisfaction items (range, 0.46–0.78). Analysis of the CSPQ found that both the Preparation and Reaction to Agent subscales indicated strong internal consistency (α = 0.98 and 0.99, respectively). ImplicationsThe PSPQ and CSPQ were developed and validated with rigorous methods. The instruments and their domains found strong internal consistency and good test-retest reliability. These questionnaires, when used as measures of treatment satisfaction in clinical trials, real-world observational studies, or by clinicians in their own laboratories, may help patients and clinicians better understand the impact of single-photon emission computed tomography myocardial perfusion imaging pharmacologic stress testing.

Comparison of the current reasons for undergoing pharmacologic stress during echocardiographic and radionuclide stress testing

BackgroundSymptom-limited exercise is the preferred method of cardiac stress testing, but pharmacologic testing has been increasing over time. The exact reasons for pharmacologic stress testing have not been rigorously categorized. Thus, we systematically explored the reasons for pharmacologic stress testing in patients referred for cardiac stress imaging. MethodsWe studied consecutive patients referred for stress imaging [stress echocardiography or radionuclide myocardial perfusion imaging (MPI)] at Mount Sinai St Luke’s hospital between August 2013 and April 2014. Baseline information was obtained using a standardized questionnaire and a trained physician triaged the patient for symptom-limited exercise stress testing or pharmacologic stress testing. ResultsIn total, 551(48%) of our entire stress cohort underwent cardiac imaging following initial exercise testing and 589 (52%) underwent imaging with initial pharmacologic stress testing. Deconditioning and inability to walk (primarily due to musculoskeletal conditions) constituted the top two reasons for performing pharmacologic stress, followed by frailty, left bundle branch block (for MPI), resting wall motion abnormality (for echocardiography), and failed exercise attempts. The reasons for performing pharmacologic stress testing were similar in the MPI and echocardiography patients, despite a much higher level of disease acuity in the MPI group. ConclusionsWe have applied a systematic approach for categorizing the reasons for pharmacologic stress. These reasons are heterogeneous, but similar across MPI and echo stress laboratories.

Dynamic single-photon emission computed tomography as a method of identification of multivessel coronary artery disease

The aim of this study was to determine the informative value of dynamic tomoscintigraphy in detection of multivessel coronary artery disease (CAD). Patients with multivessel CAD (n= 16) and healthy volunteers (n= 9) underwent dynamic cardiac single photon emission computed tomography with 99mТс-MIBI at rest and during pharmacological stress-test. Processing of acquired results involved the formation of regions of interest from the cavity and the myocardium of the left ventricle used to create activity-time curves. Coronary flow reserve index was defined as a quotient of two ratios of the mean counts from the myocardial region to the integral activity in the left ventricular cavity for the studies performed during pharmacological stress test and at rest. The mean values of coronary flow reserve index were 1.86 (1.59; 2.2) in group of healthy volunteers and 1.39 (1.12; 1.69) in patients with multivessel CAD. When the value of this index was less than 1.77, the method allowed for detection of three-vessel CAD with the sensitivity and specificity rates of 81.8% and 66.7%, respectively. Performing the standard myocardial perfusion scintigraphy in combination with the method of coronary flow reserve index assessment allows for enhancement of the diagnostic value of scintigraphic approach in the evaluation of coronary circulation disturbances in multivessel CAD.

Dynamic Single-Photon Emission Computed Tomography Data Analysis: Capabilities for Determining Functional Significance of Coronary Artery Atherosclerosis

The aim of the study was to develop the method for collecting and processing scintigraphic data to determine myocardial flow reserve by using gamma-camera with a new type detector based on Cadmium Zinc Telluride (CZT). Sixteen coronary artery disease patients and nine healthy volunteers received cardiac dynamic single-photon emission computed tomography with technetium 99m methoxyisobutylisonitrile ( 99m Tc-MIBI) at rest and during pharmacologic stress test. Data processing involved a formation of regions of interest from the left ventricular (LV) cavity and myocardial walls to build activity-time curves. Myocardial flow reserve index was determined as a quotient of two ratios of mean myocardial counts to area under a curve peak from LV cavity during stress test and at rest. Mean values of myocardial flow reserve index were 1.86 (1.59; 2.2) in group of healthy volunteers and 1.39 (1.12; 1.69) in patients with multivessel coronary artery disease. When the value of this index was less than 1.77, the method allowed for identification of multivessel disease with sensitivity and specificity of 81.8% and 66.7%, respectively. Standard myocardial perfusion scintigraphy in combination with the method of myocardial flow reserve index determination allows for increasing diagnostic significance of the scintigraphic approach for assessment of coronary microcirculation lesions in multivessel coronary artery disease.

Blepharoptosis: diagnostic tests

The article discusses diagnostic algorithms for blepharoptosis in patients with Horner's syndrome, myasthenia, chronic progressive ophthalmoplegia, myotonic dystrophy, and acute neurovascular events. Basic methods for evaluating the upper eyelid position and ptosis severity as well as special pharmacologic stress tests to reveal the true etiology of the condition and make the best treatment choice are described.

Post-operative myocardial infarction complicating donor hepatectomy: Implications for donor safety.

Sir, A 56-year-old post-menopausal lady was evaluated as a liver donor for her daughter who had fulminant liver failure. Her medical history was unremarkable, and post-menopausal state and age above 50 years were the only associated risks. A 12-lead electrocardiogram and two-dimensional echocardiography were both normal. We identified her as intermediate surgical risk[1] with clinical cardiopulmonary reserve of six metabolic equivalents. Standard protocols for anaesthesia for hepatectomy were performed; however, an epidural catheter was abandoned in view of technical difficulty and analgesia was provided with an intravenous fentanyl infusion. The procedure lasted for 6.5 h with blood loss of 600 ml and the patient was extubated at the end of procedure. Continuous analgesia was provided with an intravenous infusion of fentanyl targeting a pain score <4 on the visual analogue scale. On the 1st post-operative day (POD), the patient was pain-free, ambulant and haemodynamically stable. Her heart rate averaged 65/min, central venous pressure 7–8 mmHg, haemoglobin 10.8 g/dL, serum aspartate aminotransferase 684 IU/L, serum alanine aminotransferase 565 IU/L and international normalised ratio (INR) 1.46. On the second POD, the patient developed sudden hypotension with cardiac arrest. There was no evidence of hypovolaemia or bleeding at the surgical site. Standard cardiopulmonary resuscitation was initiated with successful return of spontaneous circulation after two cycles. The blood pressure was then maintained with infusions of adrenaline and dopamine. A 12-lead electrocardiogram suggested an inferolateral wall ST-elevation myocardial infarction [STEMI, Figure 1]. A coronary angiogram showed 80% stenosis of the distal right coronary artery with normal flow in all other vessels. Percutaneous coronary intervention was performed with a bare metal stent that was exchanged for a covered stent following perforation at the site of stenting. A pigtail catheter was inserted into the pericardial sac [Figure 2]. Infusion of eptifibatide and intravenous heparin were administered at the time of intervention. The patient bled 1.8 L from the abdominal drain and 330 ml from the pericardial sac, for which she was transfused two units of packed red blood cells and two units of fresh frozen plasma (INR was 4.23). She was weaned off the ventilator on the 4th day following intervention and was discharged on the 16th POD. Figure 1 Electrocardiogram showing inferolateral wall ST-elevation myocardial infarction Figure 2 Pigtail catheter in the pericardial sac Despite guidelines for donor selection,[2] emotional factors and donor availability confound the selection in life-threatening situations. Donor deaths range from 0.5% to 2% in right hepatectomy, and myocardial infarction has also been one of the causes.[3] As history suggested a good cardiopulmonary reserve with a revised cardiac risk index[1] score of 0.9%, we did not consider the need for stress testing. An exercise stress testing, dobutamine echocardiogram or assessment of anaerobic threshold may have been predictive of major adverse cardiac events (MACE) in this patient.[1] In contrast to the American College of Cardiology guidelines,[1] the European Society of Cardiology[4] guidelines classify liver resection surgery as high surgical risk for MACE. It is possible that stress of surgery pre-disposed the STEMI following plaque rupture.[4] Percutaneous intervention was the treatment of choice as surgical revascularisation or thrombolysis is associated with increased bleeding post-operatively.[1] Although coagulation disturbances are known after major hepatectomy, epidural analgesia is considered acceptable if performed judiciously.[5] Living donation is a viable option for fulminant liver failure, and marginal donors are accepted in the background of restricted donor availability as a life-saving measure. As the donor undergoes surgery that is not indicated for his well-being, rigorous adherence to standard protocols in donor evaluation[6] even in emergent situations and communication of potential life-threatening complications is necessary for living donor transplants. In the light of our report, exercise stress testing or pharmacological stress testing for prediction of MACE should be considered in high surgical risk procedures including donor hepatectomy. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Abstract 19616: Regadenoson Administration During Pharmacological Stress Test Causes Prolonged Qtc Interval

Background: Post-marketing reports have shown prolongation of QT interval with Regadenoson (Reg). We sought to investigate incidence of corrected QT (QTc) prolongation with Reg and its effect on ventricular arrhythmias in our clinical population. Methods: We conducted a retrospective analysis of 844 consecutive patients who underwent Reg myocardial perfusion imaging. EKG was analyzed for QTc and presence of ventricular ectopy. QTc was measured at baseline, 2 minutes after Reg injection and 3 minutes in recovery. Prolonged QTc interval was defined as &gt;470 milliseconds (ms) in women and &gt;450ms in men. Demographic data, medical history and medications were also obtained from medical records. Results: Mean age was 61 ± 11 years, 53% were females. We noticed statistically significant increase in mean QTc at 2 min (460.2 ± 49) compared to baseline (441.4 ± 41.7) (p &lt;0.0001). QTc interval was also increased at recovery (454.5 ± 42.7) compared to baseline (p &lt;0.001). QTc was prolonged in 231 (27.37%), 327 (38.74%) and 248 (29.38%) at baseline, 2min and recovery respectively. There were no clinically significant ventricular arrhythmias that required intervention in any of our patients. The number of new premature ventricular contractions (PVCs) after Reg injection was not significantly higher when we compared patients who had higher QTc interval at 2min compared to baseline (p=0.3). The number of new PVCs after Reg injection was significantly higher amongst patients whose baseline QTc interval was higher compared to those whose recovery-QTc interval higher (7% vs. 4%, with p=0.03). Conclusion: Qtc interval was prolonged after Reg administration during pharmacological stress testing. Higher baseline QTc and not the post Reg QTc predicted increased PVCs. Caution may be needed in patients undergoing Reg with baseline prolonged QTc.

DDEL-09QUANTIFICATION OF TRANSIENT BLOOD BRAIN BARRIER DISRUPTION FOLLOWING THE SYSTEMIC ADMINISTRATION OF REGADENOSON

BACKGROUND: The blood brain barrier (BBB) makes it difficult for oral or intravenous chemotherapy to achieve therapeutic concentrations in brain parenchyma. Regadenoson is an adenosine receptor agonist which transiently disrupts the BBB, allowing systemically administered high molecular weight dextran (MW 70kD) to enter normal rodent brain. Our recent studies with this compound suggest that temozolomide concentrations in rodent brain are also increased by regadenoson. This FDA approved agent is used routinely for cardiac stress tests in patients unable to exercise along with visipaque and cardiac computed tomography (CT) imaging. Visipaque (MW 1550) typically only enters brain where there is significant disruption of the BBB. This study is being conducted to determine if regadenoson will allow more contrast to enter normal human brain. METHODS: Patients without known intracranial disease who were undergoing clinically indicated pharmacologic cardiac stress tests (visipaque with cardiac CT followed by visipaque with regadenoson and cardiac CT) were eligible. This IRB approved study only added brain CT pre- and post-regadenoson. Contrast delivery was measured in hounsfield units (HU), at the level of the basal ganglia, within the cortex, deep gray and white matter. A total of 27 patients are required to assist in comparison analysis of regional contrast uptake. A matched-pairs t-test was performed to determine if the difference was significant. RESULTS: Five of the 27 patients have been accrued and analyzed. There was no difference in contrast following visipaque alone and visipaque with regadenoson (29.3HU vs 30.2HU respectively, P = 0.06). CONCLUSION: Early results from this ongoing study suggest that even accounting for the additional visipaque dose there is a trend towards increased contrast enhancement following regadenoson administration in patients with presumably normal brains. Transient disruption of the BBB to facilitate drug entry using an FDA approved agent could be of significant importance to the field of neuro-oncology.