Pharmacological stress test for myocardial ischemia when Adenosine is contraindicated: prospective documentation of side effects in over 700 patients with COPD or bronchial asthma

Background In the face of an increasingly elder population, physical exercise tests become less feasible with an increasing need for pharmacological stress tests, preferably with imaging techniques. For myocardial stress tests provoking myocardial ischemia, vasodilator stress is most frequently used. Whereas Dipyridamole should be obsolete, the predominant drug applied within this context is Adenosine for myocardial scintigraphy, magnetic resonance imaging and FFR. Adenosine, however, is contraindicated in patients with COPD or bronchial asthma, predominantly due to a possible exacerbation of bronchospasm or other pulmonary side effects. In contrast, Regadenoson, was especially developed as a highly selective A2A receptor agonist to circumvent these problems. Methods Regadenoson was applied with the standard injection dose of 400 μg in 780 consecutive patients with a history of COPD or bronchial asthma for SPECT myocardial perfusion scintigraphy. 12% of the patients had a preexisting first degree AV-block. Blood pressure, heart rate and possible side effects were prospectively monitored and documented for 10 minutes after the injection. Results The mean age was 70.8±8.9 years, 52% of the patients were female, 48% were male. 69% had a history of COPD and 31% of bronchial asthma. The maximum increase in heart rate was significant from 66.1±8.1 to 98.3±17.4 bpm. The maximum decrease in systolic blood pressure was significant from 124.3±12.9 to 117.3±24.7 mmHg. Most frequent side effects were a feeling if increased breathing (73%), headache (22%), feeling of warmth (22%), pressure in the stomach (17%) and pressure in the chest (16%). Complications: only 1 patient (without preexisting first degree AV-block) developed a systolic drop in blood pressure from 107 to 60 mmHg with transient severe dyspnoea. No induction of bronchospasm or other pulmonary side effects were observed. Conclusion In patients with COPD or bronchial asthma undergoing a pharmacological stress test, Adenosine is contraindicated due to its – potentially severe – pulmonary side effects, Regadenoson is the vasodilator of choice in these patients. In our series, no severe complication was observed – even not in patients with a preexisting first degree AV-block. Funding Acknowledgement Type of funding source: None

Myocardial Perfusion SPECT 2018 in Germany: Results of the 8th Survey

Aim This paper presents the results of the 8th survey of myocardial perfusion SPECT (MPS) from the reporting year 2018. Methods 291 questionnaires (184 practices (PR), 77 hospitals (HO), 30 university hospitals (UH)) were evaluated. Results of the last survey from 2015 are set in squared brackets. Results MPS of 145 930 [121 939] patients were reported (+ 19.6 %). 76 % [78 %] of all patients were studied in PR, 16 % [14 %] in HO, and 8 % [8 %] in UH, mostly with a 2-day-protocol 48 % [50 %]. 99.96 % [98 %] of all MPS were performed with Tc-99 m radiopharmaceuticals and in 0.04 % with Tl-201.A pharmacological stress test was applied in 49 % [43 %] (23 % [22 %] adenosine, 26 % [20 %] regadenoson, dipyridamole or dobutamine together < 1 % [1 %]). Attenuation correction was performed in 26 % [25 %] of all MPS, gated SPECT in 86 % [80 %] of stress MPS, in 87 % [78 %] of rest and in 83 % [76 %] of all stress and rest MPS. 67 % [53 %] of the departments performed MPS scoring by default, whereas 16 % [24 %] did not apply this feature at all.69 % [60 %] reported an increase or no changes in their MPS patient numbers. One hundred twenty-six departments which participated in the surveys from 2009 to 2018 reported an increase in MPS by 44 %. 69 % [70 %] of the MPS were requested by ambulatory care cardiologists. Conclusion The 2018 MPS survey reveals a high-grade adherence of routine MPS practice to current guidelines. The positive development in MPS performance and MPS numbers observed since 2012 remains ongoing.

Theophylline and Caffeine as Alternatives During an Aminophylline Shortage

The latest aminophylline shortage has prompted a need for alternative reversal agents for pharmacological stress testing. Cardiac stress testing is common for diagnosis and prognosis in patients with coronary heart disease. Options for pharmacological stress test agents include adenosine, regadenoson, dipyridamole, and dobutamine, whereas aminophylline is the recommended reversal agent. Adenosine and dobutamine can be used as alternatives to regadenoson and dipyridamole to decrease or eliminate the use of aminophylline. Alternatives to aminophylline include theophylline and caffeine. It is important to efficiently identify alternatives during a drug shortage to maintain optimal patient outcomes.

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 MP44: Assessment and Comparison of Six minute Walk Distance in Patients Undergoing Pharmacological Stress Test

Background: Stress testing is widely used for diagnosis, risk stratification and prognosis of patients (pts). Although a normal stress study identifies pts at low risk, compared to exercise stress (Ex), those undergoing pharmacological stress test (PST) are at a higher risk of mortality. We studied the feasibility of a six minute walk test (SMWT) and compared the six-minute walk distance (SMWD) among Ex and PST. Methods: 328 consecutive patients [Ex=186 (57%); PST= 142 (43%)] referred for stress testing at our hospital were enrolled. Demographic and clinical information was collected. Each patient underwent a SMWT according to American Thoracic Society guidelines. Results: Patients in PST were older (62±14 vs. 57±12; p=0.001), had a higher BMI (36±30 vs. 29±6; p0.01), diabetes (46% vs. 25%; p<0.001) and hyperlipidemia (55% vs. 38%; p=0.01). We found a low SMWD achieved in PST (209 m ± 131) vs. Ex (366 m ± 107; p<0.001). When compared to age-gender matched healthy volunteer data, we found a significantly lower predicted SMWD in all patients suspected of CAD, with the lowest predicted SMWD in PST. (Figure) On multivariate analyses, patients undergoing PST had the highest risk (HR=10.1) of achieving lowest tertile of percent predicted SMWD, followed by female gender (HR=2.0), history of CHF, higher BMI. Only patients above 80 yrs of age had significant higher likelihood of undergoing pharmacological stress mode (OR = 7.2; 95CI =1.7 - 30.1; p=0.008). After including the interaction term for age and pharmacological stress mode, low SMWD among PST was seen in both older and young patients (p for interaction=0.46). Conclusion: SMWT is feasible in patients referred for PST. Patients with known or suspected CAD achieve a low percent predicted SMWD. This is the first study to show objective evidence of deconditioning in PST irrespective of co-morbidities. Future studies are needed to evaluate the prognostic significance of SMWT in patients undergoing pharmacological stress test.

Study of efficacy and safety of pharmacological stress tests in nuclear cardiology

Background/Aim. Treadmill test combined with myocardial perfusion scintigraphy (MPS) is a commonly used technique in the assessment of coronary artery disease. Many patients who cannot adequately perform exercise stress testing may nevertheless undergo pharmacological tests, most commonly with the vasodilator agents (adenosine and dipyridamole), as well as the positive inotropic agent dobutamine. Patients undergoing vasodilators stress testing with either dipyridamole or adenosine also perform simultaneous low-intensity exercise. The aim of this study was to compare various pharmacological stress tests alone or in combination with low intensity exercise as preparation for MPS in reagard to incidence of adverse effects, quality of diagnostic image and the acquisition initial time. Methods. A total of 2 205 patients underwent pharmacological stress tests. Pharmacological stress test with adenosine was applied in 493 patients. In 405 of them we performed concomitant low level exercise (50 W) by bicycle ergometar (AdenoEX). In 88 of them we performed adenosine abbreviated protocol (AdenoSCAN). In 1 526 patients we performed pharmacological stress test with dipyridamole. In 871 of them we performed concomitant low level exercise (50 W) by bicycle ergometar (DipyEX), and in 775 we used only dipyridamole protocol (DipySCAN). In 186 patients we used pharmacological stress test with dobutamine. We followed side effects of adenosine, dipyiridamole and dobutamine, compared results between protocols with concomitant low level exercise and vasodilatators only. We also compared image quality, and suggested time of acquisition after stress test. Results. We found numerous side effects especially with adenosine, but these effects were short-lived and not required active interventions. Benefit with concomitant exercise in booth AdenoEX and DipyEX included decreased side effects (AdenoEX vs AdenoSCAN 62% vs 87%, respectively, and DipyEX vs DipySCAN 37% vs 59%, respectively) improved safety and patients tolerance, improved target-to-background ratios because of less subdiaphragmal activity, and earlier acquisition time. Because of producing a lot of arrhythmias (in 49% of patients) dobutamin was considered a last choice for pharmacological stress testing. Conclusion. Safety and efficacy of vasodilatators (adenosine, dipyridamole) pharmacological stress tests are good, but with concomitant exercise even better. The safety and efficacy of adenosin are better than those of dipyridamole. AdenoEX protocol provides good safety and patients tolerance. In light of these benefits we recommend AdenoEX whenever possible. Dobutamine is the last pharmacological toll for MPS.