Current status of myocardial perfusion imaging after percutaneous transluminal coronary angioplasty

AbstractControversy exists with regard to the diagnostic accuracy and optimal technique of myocardial perfusion imaging after coronary angioplasty. Exercise treadmill testing is inexpensive, with adequate predictive value for restenosis and clinical events in patients with single vessel coronary angioplasty with a normal rest electrocardiogram (ECG). Myocardial tomography has advantages for assessing patients with multivessel coronary angioplasty. Exercise stress imaging is generally preferable to pharmacologic stress in patients without physical limitations after angioplasty. Delayed thallium-201 imaging and reinjection protocols may be useful to reconcile whether residual ischemia exists in “fixed” perfusion defects. Appropriately timed stress myocardial perfusion imaging 2 to 4 weeks after procedurally successful coronary angioplasty can document improved cardiac functional capacity and reduced ECG and imaging evidence of myocardial ischemia. Although routine serial postangioplasty evaluations cannot be recommended, stess myocardial imaging may be valuable in subjects with defective anginal nocioception or extensive myocardium at risk in the area subtended by the angioplasty vessel

Adenosine Thallium-201 Tomography in Evaluation of Graft Patency Late After Coronary Artery Bypass Graft Surgery

AbstractObjectives. We sought to ascertain the utility of adenosine thallium-201 tomography for assessing graft stenoses late after coronary artery bypass graft surgery.Background. Although pharmacologic perfusion imaging has been increasingly used in the assessment of patients with coronary artery disease, the value of this stress modality for detecting coronary artery bypass graft stenosis late after surgery is unknown.Methods. We studied 109 patients who underwent both adenosine thallium-201 tomography and coronary angiography at 6.7 ± 4.8 (mean ± SD) years after coronary artery bypass graft surgery. Adenosine thallium-201 tomography was assessed quantitatively by computer-generated polar maps of the myocardial thallium-201 activity.Results. On coronary angiography, significant graft stenoses were present in 68 patients, 65 of whom had a corresponding perfusion defect as shown by thallium-201 tomography (sensitivity 96%). Significant stenoses were present in 107 (37.8%) of 283 grafts. The overall specificity by quantitative tomography was 61%. Seventy percent of the apparently false positive perfusion defects could be explained on the basis of unbypassed native disease or by the presence of fixed defects in patients with previous myocardial infarction.Conclusions. Thus, results of adenosine thallium-201 tomography are nearly always abnormal in patients with late coronary graft stenosis. Most of the false positive defects appear to be due to either unbypassed native disease or a previous myocardial infarction.(J Am Coll Cardiol 1997;29:1290–5

Identification of Hibernating Myocardium: Comparative Accuracy of Myocardial Contrast Echocardiography, Rest-Redistribution Thallium-201 Tomography and Dobutamine Echocardiography

AbstractObjectives. We sought to evaluate the comparative accuracy of myocardial contrast echocardiography (MCE), quantitative rest-redistribution thallium-201 (Tl-201) tomography and low and high dose (up to 40 μg/kg body weight per min) dobutamine echocardiography (DE) in identifying myocardial hibernation.Background. Myocardial contrast echocardiography can assess myocardial perfusion and may therefore be useful in predicting myocardial hibernation. However, its accuracy in comparison to myocardial perfusion scintigraphy and to that of high dose DE remains to be investigated.Methods. Eighteen patients (aged [±SD] 57 ± 10 years) with stable coronary artery disease and ventricular dysfunction underwent the above three modalities before coronary revascularization. Myocardial contrast echocardiography was achieved with intracoronary Albunex. Rest echocardiographic and Tl-201 studies were repeated ≥6 weeks after revascularization.Results. Of 109 revascularized segments with severe dysfunction, 46 (42%) improved. Left ventricular ejection fraction increased from 38 ± 14% to 45 ± 13% at follow-up (p = 0.003). Rest Tl-201 uptake and the ratio of peak contrast intensity of dysfunctional to normal segments with MCE were higher (p < 0.01) in segments that recovered function compared with those that did not. Myocardial contrast echocardiography, thallium scintigraphy and any contractile reserve during DE had a similar sensitivity (89% to 91%) with a lower specificity (43% to 66%) for recovery of function. A biphasic response during DE was the most specific (83%) and the least sensitive (68%) (p < 0.01). The best concordance with MCE was Tl-201 (80%, kappa 0.57). Changes in ejection fraction after revascularization related significantly to the number of viable dysfunctional segments by all modalities (r = 0.54 to 0.65).Conclusions. In myocardial hibernation, methods evaluating rest perfusion (MCE, Tl-201) or any contractile reserve have a similar high sensitivity but a low specificity for predicting recovery of function. A limited contractile reserve (biphasic response) increases the specificity of DE. Importantly, the three techniques identified all patients who had significant improvement in global ventricular function.(J Am Coll Cardiol 1997;29:985–93)© 1997 by the American College of Cardiolog

End-diastolic wall thickness as a predictor of recovery of function in myocardial hibernation Relation to rest-redistribution Tl-201 tomography and dobutamine stress echocardiography

AbstractOBJECTIVESThe study assessed whether end-diastolic wall thickness (EDWT), measured with echocardiography, is an important marker of myocardial viability in patients with suspected myocardial hibernation, and it compared this index to currently established diagnostic modalities of dobutamine stress echocardiography (DSE) and rest-redistribution thallium-201 (Tl-201) scintigraphy.BACKGROUNDBecause myocardial necrosis is associated with myocardial thinning, preserved EDWT may provide a simple index of myocardial viability that is readily available from the resting echocardiogram.METHODSAccordingly, 45 patients with stable coronary artery disease and ventricular dysfunction underwent rest 2D echocardiograms, DSE and rest-redistribution Tl-201 tomography before revascularization and a repeat resting echocardiogram ≥2 months later.RESULTSGlobal wall motion score index decreased from 2.38 ± 0.73 to 1.94 ± 0.82 after revascularization (p < 0.001). Thirty-eight percent of severely dysfunctional segments recovered resting function. Compared to segments without recovery of resting function, those with recovery had greater EDWT (0.94 ± 0.18 cm vs. 0.67 ± 0.22 cm, p ≤ 0.0001) and a higher Tl-201 uptake (78 ± 13% vs. 59 ± 21%; p < 0.0001). An EDWT >0.6 cm had a sensitivity of 94% and specificity of 48% for recovery of function. Similarly, a Tl-201 maximal uptake of ≥60% had a sensitivity of 91% and specificity of 50%. Receiver operating characteristic curves for prediction of recovery of regional and global function were similar for EDWT and maximum Tl-201 uptake. Combination of EDWT and any contractile reserve during DSE for recovery of regional function improved the specificity to 77% without a significant loss in sensitivity (88%).CONCLUSIONSEnd-diastolic wall thickness is an important marker of myocardial viability in patients with suspected hibernation, and it can predict recovery of function similar to Tl-201 scintigraphy. Importantly, a simple measurement of EDWT ≤0.6 cm virtually excludes the potential for recovery of function and is a valuable adjunct to DSE in the assessment of myocardial viability

ACC/AHA/ASNC Guidelines for the Clinical Use of Cardiac Radionuclide Imaging—Executive Summary: A Report of the American College of Cardiology/American HeartAssociation Task Force on Practice Guidelines (ACC/AHA/ASNC Committee to Revise the 1995 Guidelines for the Clinical Use of Cardiac Radionuclide Imaging)

The American College of Cardiology (ACC)/American Heart Association (AHA) Task Force on Practice Guidelines regularly reviews existing guidelines to determine when an update or full revision is needed. Guidelines for the Clinical Use of Cardiac Radionuclide Imaging were originally published in 1986 and updated in 1995. Important new developments have continued to occur since 1995, particularly in the areas of acute and chronic ischemic syndromes and heart failure. The Task Force therefore believed the topic should be revisited de novo and invited the American Society for Nuclear Cardiology (ASNC) to cosponsor the undertaking, which represents a joint effort of the 3 organizations