Comparison of Post-Exercise and Post-Vasodilator Stress Myocardial Stunning as Assessed by Electrocardiogram-Gated Single-Photon Emission Computed Tomography

Abstract

lthough stress-induced wall motion abnormalities usually disappear rapidly once myocardial ischemia is eliminated, there are a few cases in which wall motion abnormalities remain, even >30 min after elimination of the ischemia; myocardial stunning is the apparent mechanism in such cases. [1][2][3][4][5][6] The characteristics of technetium-99m ( 99m Tc)-sestamibi, which rarely redistributes, 7 in conjunction with electrocardiogram-gated single-photon emission computed tomography (SPECT) enables assessment of both myocardial ischemia during stress and left ventricular wall motion and function at least 30 min after the stress. 8,9 Although myocardial stunning has been mainly shown after exercise-induced ischemia, 1-6 pharmacologic vasodilation, which induces maldistribution of the blood flow in the intramyocardium, is commonly used as the method of inducing stress during myocardial perfusion imaging. Therefore, the aims of the present study were to evaluate the myocardial stunning induced by standard stress tests in clinical practice, and to compare the development of myocardial stunning with either exercise or pharmacologic stress. Methods SubjectsThe subjects were 179 consecutive patients with known or suspected coronary artery disease (CAD), who underwent exercise or adenosine triphosphate disodium (ATP) stress myocardial perfusion imaging. Patients with a history of coronary angioplasty or bypass graft surgery were considered to have known CAD, whereas those with a clinical risk profile, symptoms or electrocardiographic abnormalities were considered as having suspected CAD. Patients with a history of prior myocardial infarction were excluded. In total, there were 112 men and 67 women, with a mean age of 66±9 years, and 77 of them underwent coronary angiography because of clinical symptoms, electrocardiographic abnormalities or scintigraphic findings. Of those with known CAD, 50 patients had a history of coronary revascularization (coronary angioplasty in 39 patients, coronary artery bypass grafting in 11). Written informed consents were given by all participants. Stress 99m Tc-Sestamibi SPECTStress myocardial SPECT with 99m Tc-sestamibi was performed using a 1-day exercise -rest protocol. 10 Exercise Background Exercise gated single-photon emission computed tomography (SPECT) using technetium-99m ( 99m Tc)-sestamibi evaluates both myocardial perfusion during stress and wall motion >30 min after the stress, which has the potential to assess not only exercise-induced myocardial ischemia but also the development of myocardial stunning. Methods and ResultsTo evaluate the incidence of post-stress myocardial stunning, as well as comparing the effects of different stress methods on the development of stunning, 179 consecutive patients with known or suspected coronary artery disease (CAD) underwent 99m Tc-sestamibi SPECT with either exercise (n=135) or adenosine triphosphate disodium (ATP) (n=44). Electrocardiogram-gated SPECT images were acquired >30 min after the stress and again 4 h later, and perfusion and wall mo...

Preoperative Risk Stratification With Myocardial Perfusion Imaging in Intermediate and Low-Risk Non-Cardiac Surgery

“…[20][21][22] However, we found that a post-stress EF depression was not associated with adverse outcome in terms of perioperative cardiac events. This is probably because we used dipyridamole instead of exercise stress, which increases myocardial oxygen consumption and facilitates the likelihood of post-ischemic stunning.…”

“…The stress LVEF -rest LVEF value was also calculated to obtain an index reflecting post-ischemic stunning. [20][21][22] The presence of wall motion abnormality was defined as the presence of segmental hypokinesis visually diagnosed through the cine mode display of the QGS program.…”

Myocardial Stunning During Gated Spect Indicates Presence of Severe Coronary Artery Disease. Biswas,G.** Shukkur, A.M.* Sayed, M.** Alsayed, Y.** and Masoud, M.** Department of Nuclear Medicine **and Cardiology*, Chest Hospital, Kuwait.

“…Studies have shown that inhibiting leukocyte adhesion or scavenging oxygen free radicals can reduce reperfusion-associated ventricular dysfunction, arrhythmias, and infarct size [7] . Ischemic stunning after dipyridamole stress gated SPECT may be an indicator of severe and extensive CAD [8] . The magnitude of transient wall motion abnormality after exercise was greater in patients with severe ischemia compared to those with mild to moderate ischemia.…”

“…Less extensive CAD was seen in patients with mild to moderate ischemia [SDS 2-6] on coronary angiography. In a landmark study, Hung et al showed the value of ischemic stunning after dipyridamole stress gated SPECT in the detection of severe and extensive CAD [8] . In another study by Tanaka et al (2005) noticed that the magnitude of transient wall motion abnormality after exercise was greater in patients with severe ischemia compared to those with mild to moderate ischemia and significant correlation was found between summed difference score [SDS] and transient wall motion abnormality after exercise [9] .…”

Usefulness of Phase Analysis to Differentiate Ischemic and Non-Ischemic Etiologies of Left Ventricular Systolic Dysfunction in Patients With Heart Failure

“…Although previous studies compared post-stress LV regional wall motion change between exercise and ATP stress, post-stress myocardial change was rarely observed after ATP stress. 46 Whether a sophisticated nuclear cardiology imaging method may have an impact on the detection of a small change in LV regional wall motion and provide further diagnostic utility such as in ischemic cardiomyopathy, however, remains to be determined.…”