Effect of intramyocardial injection of autologous bone marrow-derived mononuclear cells on perfusion, function, and viability in patients with drug-refractory chronic ischemia.

Intramyocardial injection of bone marrow cells has been proposed as a new therapeutic option for patients with chronic ischemic heart disease. We investigated whether autologous bone marrow-derived mononuclear cell injection into the myocardium of patients with drug-refractory ischemia reduces anginal symptoms, improves left ventricular (LV) function, increases myocardial perfusion, and alters the extent of scar tissue. METHODS: In 25 patients (mean age +/- SD, 64 +/- 10 y; 21 male) with drug-refractory angina pectoris (Canadian Cardiovascular Society [CCS] class III-IV), despite optimized medical therapy and without options for conventional revascularization, bone marrow was aspirated from the iliac crest. Mononuclear cell injections were targeted at myocardial regions with stress-induced ischemia on gated (99m)Tc-tetrofosmin SPECT. Anginal symptoms were reassessed at 3- and 6-mo follow-up. At baseline and 3-mo follow-up, gated (99m)Tc-tetrofosmin SPECT and (18)F-FDG SPECT were performed to assess LV function, LV volumes, myocardial perfusion (stress and rest, 17-segment model), and extent of scar tissue. RESULTS: Mean CCS score improved from 3.4 +/- 0.6 at baseline to 2.3 +/- 0.6 at 3 mo (P < 0.01) and remained unchanged at 6 mo (2.3 +/- 0.6; P < 0.01 vs. baseline and P = not significant [NS] vs. 3 mo). Gated (99m)Tc-tetrofosmin SPECT demonstrated an increased LV ejection fraction (from 47.6% +/- 13.5% to 54.1% +/- 16.9%; P < 0.01) and a reduced LV end-systolic volume (from 81 +/- 68 mL to 75 +/- 70 mL; P < 0.01). Segmental regional wall thickening increased from 34% +/- 12% at baseline to 39% +/- 17% at 3-mo follow-up (P = 0.01). The number of segments with stress-inducible ischemia per patient decreased from 4.6 +/- 3.2 to 2.0 +/- 2.6 (P < 0.01). Both segmental stress and segmental rest score improved, although the improvement in stress score was more pronounced (decrease in segmental stress score 0.22 +/- 0.20 vs. decrease in segmental rest score 0.04 +/- 0.06; P < 0.01). Myocardial perfusion improved in 53% of the injected segments and in 13% of the noninjected segments (P < 0.01). The percentage of myocardial segments with some extent of scar remained unchanged at 3-mo follow-up (13% vs. 12%; P = NS). CONCLUSION: Autologous bone marrow-derived mononuclear cell injection in patients with drug-refractory angina and chronic ischemia improves anginal symptoms, increases LV function, and predominantly enhances myocardial stress perfusion in injected segments, whereas the extent of myocardial scar tissue remains unchanged.     

Comparison of contrast-enhanced MRI with (18)F-FDG PET/201Tl SPECT in dysfunctional myocardium: relation to early functional outcome after surgical revascularization in chronic ischemic heart disease.

Revascularization of viable myocardial segments has been shown to improve left ventricular (LV) function and long-term prognosis; however, the surgical risk is comparatively higher in patients with a low ejection fraction (EF). We compared contrast-enhanced MRI with (18)F-FDG PET/(201)Tl SPECT for myocardial viability and prediction of early functional outcome in patients with chronic coronary artery disease (CAD). METHODS: Forty-one patients with chronic CAD and LV dysfunction (mean age +/- SD, 66 +/- 10 y; 32 men; mean EF +/- SD, 38% +/- 13%) referred for (18)F-FDG PET, (201)Tl-SPECT and MRI within 2 wk were included. Twenty-nine subjects underwent coronary artery bypass grafting (CABG), and LV function was reassessed by MRI before discharge (17 +/- 7 d after surgery). Two were excluded from outcome analysis (1 death due to sepsis; 1 perioperative myocardial infarction). The extent of viable myocardium by (18)F-FDG PET/(201)Tl SPECT was defined by the metabolism-perfusion mismatch or ischemia, in comparison with the extent of delayed enhancement (DE) on MRI in a 17-segment model. Segmental functional recovery was defined as improvement in the wall motion score of > or =1 on a 4-point scale. EF and LV volume change were used as global functional outcome. RESULTS: Three hundred ninety-four dysfunctional segments were compared, and the extent of DE on MRI correlated negatively with the viability on (18)F-FDG PET. Of 252 dysfunctional segments that were successfully revascularized, the sensitivity, specificity, positive predictive value, and negative predictive value of PET/SPECT were 60.2%, 98.7%, 76.6%, and 96.7% and of MRI were 92.2%, 44.9%, 72.4%, and 78.6% using the cutoff value of 50% DE on MRI, without significant differences in overall accuracies. In 18 subjects who underwent isolated CABG, improvement of EF (> or =5%) and reverse LV remodeling (> or =10% LV size reduction) was best predicted by the no DE on MRI, and patients with substantial nonviable myocardium on (18)F-FDG/SPECT predicted a poor early functional outcome (all P < 0.001). CONCLUSION: Accurate prediction of early functional outcome by PET/SPECT and contrast-enhanced MRI is possible.     

TI-201 washout rate in remote normal regions in patients with prior myocardial infarction and left ventricular remodeling

BACKGROUND: Myocardial characteristics of remote normal regions in patients with myocardial infarction (MI) and left ventricular (LV) remodeling have not been fully elucidated. Thus, we investigated this issue from the viewpoint of myocardial Tl-201 dynamics. METHODS AND RESULTS: In 14 patients with prior anterior MI, 10 with inferior MI, and 14 age-matched patients with atypical chest pain served as controls; exercise stress Tl-201 SPECT and cardiac catheterization were performed. Tl-201 washout rate was calculated for 8 myocardial segments, and LV end-diastolic volume index was obtained as a parameter of LV remodeling. LV end-diastolic volume index was greater in anterior MI patients than in control patients; in contrast, no significant difference was observed between inferior MI patients and control patients. The washout rate in remote normal regions was significantly less in anterior MI patients than in the corresponding segments in control patients (39.8% +/- 8.7% vs 48.4% +/- 4.4%, P < .01). There was no significant difference between inferior MI patients and control patients (43.6% +/- 6.9% vs 47.8% +/- 4.5%). CONCLUSIONS: Reduced Tl-201 washout rates in remote normal regions are found in patients with anterior MI and LV remodeling. Subclinical myocardial ischemia during exercise in remote normal regions exists and may be related to the pathologic condition of such LV walls.     

Prediction of recovery of left ventricular dysfunction after acute myocardial infarction: comparison between 99mTc-sestamibi cardiac tomography and low-dose dobutamine echocardiography.

The aim of this study was to evaluate the role of 99mTc-sestamibi cardiac imaging and dobutamine echocardiography in detecting myocardial viability early after acute myocardial infarction. METHODS: Forty-nine patients (mean age 52 +/- 10 y) underwent coronary angiography, low-dose dobutamine echocardiography, radionuclide angiography and rest 99mTc-sestamibi imaging within 10 d after myocardial infarction. Of these patients, 19 were revascularized and 30 were treated medically. Resting echocardiogram and radionuclide angiography were repeated 8 mo later to evaluate segmental functional recovery and changes in left ventricular (LV) ejection fraction, respectively. RESULTS: In revascularized patients, 61 of 108 akinetic or dyskinetic segments showed functional recovery. In these patients, sensitivity in predicting segmental functional recovery was 87% for sestamibi imaging and 66% for dobutamine echocardiography (P < 0.001), whereas specificity and accuracy were comparable. Sestamibi activity (> or =55% of peak) was the strongest predictor of segmental functional recovery (P < 0.001) and of LV ejection fraction improvement > or =5% (P < 0.01) after revascularization. In medically treated patients, 60 of 149 akinetic or dyskinetic segments showed functional recovery. In these patients, the majority (94%) of segments with contractile reserve on dobutamine were viable on sestamibi imaging and 86% of them improved function at follow-up. Functional recovery was poor in segments without contractile reserve either with (38%) or without (62%) preserved sestamibi uptake. Inotropic response was the best predictor of segmental (P < 0.001) and global (P < 0.01) LV functional improvement in medically treated patients. CONCLUSION: Dobutamine echocardiography predicts spontaneous functional recovery after acute myocardial infarction. However, sestamibi imaging is useful to identify patients with dysfunctional myocardium without contractile reserve who may benefit from coronary revascularization.     

Evaluation of the clinical value of combination of 99mTc-MIBI myocardial SPECT and 18F-FDG PET in assessing myocardial viability.

PURPOSE: To evaluate the value of 18F-FDG PET metabolic imaging and 99mTc-MIBI SPECT in the identification of myocardial viability in patients with previous myocardial infarction and left ventricular dysfunction. METHODS: 18F-FDG PET (made in China) and 99mTc-MIBI SPECT were performed in 60 patients (pts) (age 54+/-9 yr) with myocardial infarction before revascularization. Before and after revascularization, LVEF and wall motion were measured with echocardiography in 36 pts (Group A), and myocardial perfusion was evaluated in 24 pts (Group B). RESULTS: According to the interpretation of perfusion and metabolic images, myocardial segments were classified into mismatch (MM): reduced myocardial perfusion and normal FDG uptake or match (M): reduced perfusion and FDG uptake. Out of 264 segments with hypoperfusion, 145 (54.9%) were MM, suggesting viable myocardium (G-A1 and G-B1), 119 (45.1%) were M, suggesting necrosis (G-A2 and G-B2). After revascularization, LVEF was increased in G-A1 (49+/-15% vs. 59+/-7%, p<0.05), and in G-B1 (50+/-8% vs. 59+/-12%, p<0.05), but was not improved in G-A2 and G-B2. LVEDD was decreased in G-A1 and G-B1 (p<0.05) and was unchanged in G-A2 and G-B2. The positive predictive value (PPV) of FDG PET for improvement of regional wall motion after revascularization was 88%, and the negative predictive value (NPV) was 72.6%. The PPV for improvement of perfusion was 84.1%, NPV was 85%, and accuracy was 84.4%. CONCLUSION: 18F-FDG imaging with Chinese PET has clinical value for assessing myocardial viability and identifying patients who will benefit from revascularization.     

Relationship between preoperative viability and postoperative improvement in LVEF and heart failure symptoms.

The presence of myocardial viability is predictive of improvement in regional left ventricular (LV) function after revascularization. Studies on predicting improvement in global LV function are scarce, and the amount of viable myocardium needed for improvement in LV ejection fraction (LVEF) after revascularization is unknown. Moreover, whether the presence of viability is associated with relief of heart failure symptoms after revascularization is uncertain. Hence, the aims were to define the extent of viable myocardium needed for improvement in LVEF and to determine whether preoperative viability testing can predict improvement in heart failure symptoms. METHODS: Patients (n = 47) with ischemic cardiomyopathy (mean LVEF +/- SD, 30% +/- 6%) undergoing surgical revascularization were studied with 18F-FDG SPECT to assess viability. Regional and global function were measured before and 3-6 mo after revascularization. Heart failure symptoms were graded according to the New York Heart Association (NYHA) criteria, before and 3-6 mo after revascularization. RESULTS: The number of viable segments per patient was directly related to the improvement in LVEF after revascularization (r = 0.79, P < 0.01). Receiver operating characteristic curve analysis revealed that the cutoff level of four viable segments (representing 31% of the left ventricle) yielded the highest sensitivity and specificity (86% and 92%, respectively) for predicting improvement in LVEF. Furthermore, the presence of four or more viable segments predicted improvement in heart failure symptoms after revascularization, with positive and negative predictive values of 76% and 71%, respectively. CONCLUSION: The presence of substantial viability (four or more viable segments, 31% of the left ventricle) on FDG SPECT is predictive of improvement in LVEF and heart failure symptoms postoperatively.     

Intramyocardial Implantation of bone marrow-derived stem cells enhances perfusion in chronic myocardial infarction: dependency on initial perfusion depth and follow-up assessed by gated pinhole SPECT.

Cell therapy-induced changes in the perfusion of areas of myocardial infarction (MI) remain unclear. This study investigated whether an original pinhole SPECT technique could be applied to a rat MI model to analyze local improvement in myocardial perfusion relating to engraftment sites of bone marrow-derived stem cells (BMSCs). METHODS: Four-month-old MI rats were either untreated (n = 8) or treated (n = 10) by intramyocardial injection of (111)In-labeled BMSCs. Early distribution of (111)In-BMSCs within the MI target was evidenced by dual (111)In/(99m)Tc pinhole SPECT 48 h later. Myocardial perfusion was serially monitored by (99m)Tc-sestamibi pinhole gated SPECT up to 3 mo after transplantation. RESULTS: Forty-eight hours after transplantation, (111)In-BMSCs were observed in all treated rats and in 18 of their 32 underperfused MI segments (<70% sestamibi uptake before transplantation). During the subsequent 3-mo follow-up, the perfusion of MI segments worsened in untreated rats (absolute change in sestamibi uptake, -3% +/- 3%; P < 0.05) but improved in treated rats (+4% +/- 7%; P < 0.05). This perfusion improvement was unrelated to the initial detection of (111)In-BMSCs (+2% +/- 6% in segments with (111)In-BMSCs vs. +5% +/- 7% in those without; not statistically significant) but was strongly associated with less severe perfusion defects before transplantation (+6% +/- 6% in segments with 60%-70% sestamibi uptake [n = 19] vs. -1% +/- 6% in those with <60% uptake [n = 13]; P = 0.003). CONCLUSION: When BMSCs are injected within chronic MI, perfusion enhancement predominates in the MI areas showing a high enough residual perfusion before treatment but not in those of the initial cell engraftment, giving evidence of dependency on the perfusion and metabolic environment at implantation sites.     

Sestamibi SPECT in the detection of myocardial viability in patients with chronic ischemic left ventricular dysfunction: Comparison between visual and quantitative analysis

BACKGROUND: Technetium 99m sestamibi cardiac scintigraphy is widely used as a means of predicting myocardial viability in patients with chronic ischemic left ventricular (LV) dysfunction. No data are available comparing the results of visual and quantitative analysis of tomographic imaging in the assessment of myocardial viability. The aim of this study was to directly compare visual and quantitative analysis of resting sestamibi single photon emission computed tomography in the identification of viable myocardium in patients with chronic LV dysfunction. METHODS AND RESULTS: Sixty-five patients with an earlier myocardial infarction and LV dysfunction that had occurred within 1 week underwent echocardiography and resting sestamibi SPECT. In each patient, regional tracer distribution was visually assessed and quantitatively measured in 13 segments. Regional LV function was evaluated in corresponding segments by means of echocardiography. All patients underwent revascularization, and echocardiography was repeated 12 months later as a means of assessing the recovery of regional LV function. Among all akinetic or dyskinetic revascularized segments, 66 of 112 viable segments (59%) and 85 of 100 nonviable segments (81%) were identified by means of visual analysis. Eighty-two of 112 viable segments (73%; P<.05 vs. visual analysis) and 74 of 100 nonviable segments (74%; P = .3 vs. visual analysis) were identified by means of quantitative analysis, with a threshold of 55%. Receiver operating characteristic curve areas constructed by using visual and quantitative analyses for the detection of myocardial viability in all 212 akinetic or dyskinetic segments were 0.79+/-0.04 and 0.81+/-0.03, respectively (P = not significant). Overall concordance in the detection of myocardial viability between visual and quantitative analysis was observed in 165 of akinetic or dyskinetic dysfunctional segments (78%), with a kappa value of 0.6. CONCLUSIONS: The results of this study demonstrate that, in patients with chronic myocardial infarction and LV dysfunction, visual and quantitative analysis of sestamibi tomographic images at rest have similar overall accuracy in predicting the recovery of LV function after coronary revascularization procedures.     

Acute myocardial infarction: evaluation with first-pass enhancement and delayed enhancement MR imaging compared with 201Tl SPECT imaging

PURPOSE: To evaluate acute myocardial infarction by using first-pass enhancement (FPE) and delayed enhancement (DE) magnetic resonance (MR) imaging compared with thallium 201 ((201)Tl) single photon emission computed tomography (SPECT). MATERIALS AND METHODS: Contrast material-enhanced FPE MR, inversion-recovery DE MR, and rest-redistribution (201)Tl SPECT images were obtained in 60 consecutive patients (53 men, seven women; mean age [+/- SD], 56 years +/- 13; range, 30-78 years) at 6 days +/- 3 after reperfused first myocardial infarction. Presence of microvascular obstruction was determined on FPE MR images. Infarct size was defined on DE MR images as percentage of left ventricular (LV) area and compared with uptake defect on redistribution (201)Tl SPECT images. Differences in continuous data were analyzed with Student t test. Linear regression and Bland-Altman analysis were used to compare measurements of infarct size. RESULTS: Mean infarct size was not significantly different between DE MR imaging (20.7% +/- 11.5% of LV area) and (201)Tl SPECT (19.4% +/- 14.3% of LV area; P =.26); good correlation (r = 0.73; P <.001) and agreement were found, with a mean difference of +1.3% +/- 9.8% of LV area. (201)Tl SPECT failed to depict infarct in six (20%) of 30 patients with inferior myocardial infarction (mean size, 6.4% +/- 5.7% of LV area on DE MR images), whereas DE MR images showed the infarct in all patients (P <.01). FPE MR images depicted microvascular obstruction in 23 (38%) of 60 patients; these patients had larger infarctions at DE MR imaging than did patients without microvascular obstruction (30.4% +/- 9.0% vs 15.1% +/- 8.4% of LV area, P <.001). (201)Tl SPECT showed larger infarcts in patients with microvascular obstruction (26.7% +/- 16.2% vs 15.0% +/- 11.2% of LV area, P <.01). CONCLUSION: Good correlation and agreement with (201)Tl SPECT indicate DE MR imaging may be used to estimate infarct size 6 days after reperfused acute myocardial infarction. DE MR imaging is more sensitive for detection of inferior infarction than is (201)Tl SPECT. Patients with microvascular obstruction on FPE MR images have larger infarcts.     

Estimation of I-123 metaiodobenzylguanidine (MIBG) myocardial washout

A crosstalk from I-123 to Tl-201 (Tl) window was 35 +/- 30% (mean +/- SD) and 30 +/- 10% in a myocardial phantom and the images of 6 patients respectively. However, the crosstalk from Tl to I-123 was approximately 1% in each. I-123 MIBG (MIBG) and Tl myocardial SPECT images were recorded in 3 normal volunteers (N), 10 patients with myocardial infarction (MI), and 4 with dilated cardiomyopathy (DCM). The MIBG and Tl imagings were performed on the other day to avoid the crosstalk. Myocardial washout rates (WR) of Tl and MIBG were derived from 15 min and 4 hour images. WR of Tl was approximately 36% in each group. On the other hand, WR of MIBG in DCM (52 +/- 7%) and MI (41 +/- 14%) groups were statistically higher than in N (24 +/- 7%) group. Thus WR of MIBG would be useful to detect abnormalities in adrenergic nervous system.     

Prediction of myocardial infarction versus cardiac death by gated myocardial perfusion SPECT: risk stratification by the amount of stress-induced ischemia and the poststress ejection fraction.

The combination of myocardial perfusion and poststress ejection fraction (EF) provides incremental prognostic information. This study assessed predictors of nonfatal myocardial infarction (MI) versus cardiac death (CD) by gated myocardial SPECT and examined the value of integrating the amount of ischemia and poststress EF data in risk stratification. METHODS: We identified 2,686 patients who underwent resting (201)Tl/stress (99m)Tc-sestamibi gated SPECT and were monitored for >1 y. Patients who underwent revascularization < or = 60 d after the nuclear test were censored from the prognostic analysis. Visual scoring of perfusion images used 20 segments and a scale of 0--4. Poststress EF was automatically generated. RESULTS: Cox regression analysis showed that after adjusting for prescan data, the most powerful predictor of CD was poststress EF, whereas the best predictor of MI was the amount of ischemia (summed difference score [SDS]). Integration of the EF and SDS yielded effective stratification of patients into low-, intermediate-, and high-risk subgroups. Patients with EF >50% and a large amount of ischemia were at intermediate risk (2%--3%), whereas those with mild or moderate ischemia were at low risk of CD (<1%/y). Patients with EF between 30% and 50% were at intermediate risk even in the presence of only mild or moderate ischemia. In patients with EF <30%, the CD rate was high (>4%/y) irrespective of the amount of ischemia. CONCLUSION: Poststress EF is the best predictor of CD, whereas the amount of ischemia is the best predictor of nonfatal MI. Integration of perfusion and function data improves stratification of patients into low, intermediate, and high risk of CD.     

Evaluation of acute myocardial infarction with late enhancement pattern on MRI compared with 201Tl and 99mTc-hydroxymethylenediphosphonate (HMDP) dual single photon emission computed tomography (SPECT) images

The purpose of this study is to evaluate reperfused acute myocardial infarction with late enhancement (LE) pattern on contrast-enhanced magnetic resonance imaging compared with myocardial single photon emission computed tomography (SPECT) images. MATERIALS AND METHODS: Magnetic resonance and 201Tl and 99mTc-hydroxymethylenediphosphonate SPECT images were obtained from 40 patients within 6 days of reperfused myocardial infarction. We assessed the myocardial LE pattern using the true fast imaging with steady-state free precession sequence after the injection of Gd-DTPA. Patients were classified into 3 groups: group 1 included patients with localized endocardial enhancement; group 2, patients with transmural enhancement; and group 3, patients with LE and a residual defect. RESULTS: There were 9 patients (23%) in group 1, 15 (38%) in group 2, and 15 (38%) in group 3. In 1 patient, LE was not detected (3%). The %201Tl uptake for the infarcted area was 60.7 +/- 7.2 (mean +/- SD) for group 1, 49.5 +/- 12.3 (P < 0.05 vs. group 1) for group 2, and 36.9 +/- 8.2 (P < 0.0001 vs. group 1, P = 0.005 vs. group 2) for group 3. An overlap pattern of 201Tl and 99mTc was observed in 9 of the group 1 patients (100%) and 9 of the group 2 patients (60%), but was not evident in group 3 (0%). CONCLUSIONS: LE with residual defect is an important indicator of microvascular obstruction after reperfusion therapy.     

Serial changes on quantitative myocardial perfusion SPECT in patients undergoing revascularization or conservative therapy

BACKGROUND: Little is known about changes of myocardial perfusion in patients undergoing coronary revascularization or medical therapy. The purpose of this observational study was to assess the long-term effects of revascularization or conservative therapy on serial quantitative myocardial perfusion single photon emission computed tomography (SPECT). METHODS AND RESULTS: The study population consisted of 421 patients who underwent serial rest thallium-201/stress technetium-99m sestamibi dual-isotope myocardial perfusion SPECT with at least a 1-year interval between the 2 studies and who had abnormal quantitative scan results on the first stress SPECT. The mean interval between scans was 32.7 +/- 15.9 months. Patients were divided into 3 groups according to stress defect extent: group 1 had small stress defects (4%-10%, n = 145), group 2 had intermediate stress defects (>10%-20%, n = 144), and group 3 had extensive stress defects (>20%, n = 132) at baseline. Forty patients in group 1, 44 in group 2, and 54 in group 3 underwent coronary revascularization between 2 SPECT studies; the others had conservative therapy. In group 3 patients with revascularization, stress defect extent and reversible defect extent were remarkably reduced (14.5% +/- 13.6% and 13.1% +/- 12.5%, respectively; both P <.0001), with greater improvement in those patients reporting increased use of cardiac medications; resting defect extent was slightly reduced (1.9% +/- 6.4%, P <.05). In group 3 patients with conservative therapy, a small reduction in stress defect extent was noted (2.3% +/- 8.3%, P <.05). In group 2, there were modest, similar reductions in reversible defect extent in both the patients with revascularization (2.7% +/- 7.7%, P <.05) and those with conservative therapy (1.8% +/- 7.3%, P <.05), as well as a small but significant reduction in stress defect extent in those with conservative therapy (2.1% +/- 8.2%, P <.05). In group 1 patients, no significant changes in stress, rest, or reversible defect extent were found with either therapy. CONCLUSIONS: The findings of this study show that improvement in quantitative myocardial perfusion abnormalities over time occurs in some patients with either revascularization or conservative therapy and suggest that, in patients with extensive defects, greater improvement may be seen in those who undergo revascularization.     

Prognostic value of normal exercise 99mTc-sestamibi myocardial tomography in patients with angiographic coronary artery disease

BACKGROUND AND AIM: Previous studies have documented the prognostic value of normal exercise Tl myocardial perfusion imaging in patients with angiographic coronary artery disease (CAD). However, data on exercise Tc-sestamibi myocardial single photon emission computed tomography (SPECT) are scant. Accordingly, the purpose of this study was to investigate the prognostic value of normal exercise Tc-sestamibi SPECT in patients with angiographic CAD. METHODS: We retrospectively investigated 90 consecutive patients who had a normal exercise Tc-sestamibi myocardial SPECT but angiographic CAD. A group of 69 consecutive patients with both normal exercise Tc-sestamibi myocardial SPECT and coronary arteries were included as control. RESULTS: During a mean follow-up of 50+/-19 months, a total of three hard cardiac events (non-fatal myocardial infarction) and seven soft cardiac events (late revascularization) were observed. The annual hard cardiac event rate between the two groups was not significantly different (0.6% vs. 0.3%, chi=0.47, P=NS), nevertheless the annual soft cardiac event rate was higher in patients with angiographic CAD (1.9% vs. 0, chi=5.74, P=0.02). Moreover, the annual hard cardiac events rate in patients with angiographic CAD who were treated medically was also not significantly different from that of the control group (0.8% vs. 0.3%, chi=0.77, P=NS). Among patients with angiographic CAD, the annual hard cardiac event rate was not statistically different between those treated medically and those who underwent revascularization (0.8% vs. 0, chi=0.53, P=NS). CONCLUSIONS: Our data demonstrate that normal exercise Tc-sestamibi myocardial SPECT despite angiographic CAD suggests a low rate of cardiac death or non-fatal myocardial infarction but a relatively high rate of late revascularization during an intermediate term of follow-up.     

Non-invasive detection of ischemic left ventricular dysfunction using rest gated SPECT: expectation of simultaneous evaluation of both myocardial perfusion and wall motion abnormality

OBJECTIVE: Although the accurate detection of ischemic etiology is important in the management of patients with severe left ventricular (LV) dysfunction, it is difficult to determine using a non-invasive strategy. The present study investigates whether perfusion and regional functional abnormalities identified by quantitative electrocardiographic gated single-photon emission computed tomography (QGS) at rest can detect ischemic LV dysfunction in patients with severe LV dysfunction. METHODS: Rest QGS with (99m)Tc-tetrofosmin was performed on 54 consecutive patients with LV ejection fraction of 相似文献   

Impact of endothelial dysfunction on left ventricular remodeling after successful primary coronary angioplasty for acute myocardial infarction —Analysis by quantitative ECG-gated SPECT—

BACKGROUND: We hypothesized that endothelial cell integrity in the risk area would influence left ventricular remodeling after acute myocardial infarction. PATIENTS AND METHODS: Twenty patients (61 +/- 8 y.o.) with acute myocardial infarction underwent 99mTc-tetrofosmin imaging in the subacute phase and three months after successful primary angioplasty due to myocardial infarction. All patients were administered angiotensin-converting enzyme inhibitor after revascularization. Cardiac scintigraphies with quantitative gated SPECT were performed at the sub-acute stage and again 3 months after revascularization to evaluate left ventricular (LV) remodeling. The left ventricular ejection fraction (EF) and end-systolic and end-diastolic volume (ESV, EDV) were determined using a quantitative gated SPECT (QGS) program. Three months after myocardial infarction, all patients underwent cardiac catheterization examination with coronary endothelial function testing. Bradykinin (BK) (0.2, 0.6, 2.0 microg/min) was administered via the left coronary artery in a stepwise manner. Coronary blood flow was evaluated by Doppler flow velocity measurement. Patients were divided into two groups by BK-response: a preserved endothelial function group (n = 10) and endothelial dysfunction group (n = 10). RESULTS: At baseline, both global function and LV systolic and diastolic volumes were similar in both groups. However, LV ejection fraction was significantly improved in the preserved-endothelial function group, compared with that in the endothelial dysfunction group (42 +/- 10% to 48 +/- 9%, versus 41 +/- 4% to 42 +/- 13%, p < 0.05). LV volumes progressively increased in the endothelial dysfunction group compared to the preserved-endothelial, function group (123 +/- 45 ml to 128 +/- 43 ml, versus 111 +/- 47 ml to 109 +/- 49 ml, p < 0.05). CONCLUSION: In re-perfused acute myocardial infarction, endothelial function within the risk area plays an important role with left ventricular remodeling after myocardial infarction.     

Tetrofosmin imaging in the detection of myocardial viability in patients with previous myocardial infarction: comparison with sestamibi and tl-201 scintigraphy

BACKGROUND: Technetium 99m tetrofosmin has been introduced as a myocardial perfusion agent, providing similar results to those of thallium 201 and sestamibi in the identification of patients with coronary artery disease. No data are available comparing tetrofosmin and sestamibi imaging in the identification of reversible left ventricular (LV) dysfunction in the same patients. This study compared the results of tetrofosmin, thallium, and sestamibi single photon emission computed tomography at rest in detection of myocardial viability in patients with previous myocardial infarction. METHODS AND RESULTS: Seventeen patients with previous myocardial infarction who were undergoing coronary revascularization were studied. Echocardiography was performed at baseline and 3 months after revascularization to evaluate recovery of LV function. The optimal threshold cutoffs to separate reversible from irreversible dysfunction, as determined by receiver operating characteristic analysis, were 55% of peak activity for both tetrofosmin and sestamibi and 60% for thallium. In all asynergic segments (n = 77) analyzed, tetrofosmin uptake correlated with both sestamibi (r = 0.90, P <.0001) and thallium (r = 0.85, P <.0001) activity. The sensitivity and specificity for reversible dysfunction were, respectively, 70% and 70% for tetrofosmin, 70% and 66% for sestamibi, and 60% and 68% for thallium imaging (all P = not significant). The areas under the receiver operating characteristic curves constructed for tetrofosmin, thallium, and sestamibi activity were 0.74 +/- 0.06 (mean +/- SD), 0.75 +/- 0.06, and 0.74 +/- 0.06, respectively (all P = not significant). Concordance for detecting myocardial viability between tetrofosmin and thallium imaging was found in 67 regions (87%) (kappa = 0.74), and concordance between tetrofosmin and sestamibi imaging was found in 69 regions (90%) (kappa = 0.79). CONCLUSIONS: The diagnostic performance of quantitative rest tetrofosmin single photon emission computed tomography in predicting functional recovery after revascularization is comparable to that of both thallium and sestamibi scintigraphy in patients with myocardial infarction and chronic LV dysfunction.     

"Doughnut" technetium pyrophosphate myocardial scintigrams. A marker of severe left ventricular dysfunction

The "doughnut" pattern on Tc-99m pyrophosphate (PPi) myocardial scintigraphy is characterized by a border of tracer uptake surrounding a central zone of relatively decreased activity. This pattern is generally associated with large transmural anterior myocardial infarcts (MI) caused by occlusion or critical stenosis of the left anterior descending coronary artery. Such infarcts typically involve a significant portion of the anterior wall and are associated with a complicated clinical course and poor prognosis. In order to evaluate the relationship between the presence of the doughnut pattern and left ventricular (LV) function, radionuclide ventriculography was performed within 15 days after infarction in 58 patients with transmural anterior MI. In patients without previous MI, 15/38 (39.5%) had doughnut scintigrams. These patients demonstrated significant reductions in LV ejection fraction (EF) (28 +/- 10% versus 45 +/- 12%, P less than 0.001) and normalized LV wall motion scores (29 +/- 11% versus 61 +/- 10%, P less than 0.001) when compared with patients with "nondoughnut" scintigrams. Patients with doughnut scintigrams had a significantly greater incidence of severe septal hypokinesis (P less than 0.001) and apical dyskinesis (P less than 0.03). LV end-systolic volumes were also larger in the patients with doughnut scintigrams (73 +/- 32 ml versus 40 +/- 17 mI/M2, P less than 0.005). In contrast, there was no significant difference in LVEF, normalized LV wall motion score, or LV volumes between doughnut and nondoughnut groups in patients with previous MI.     

Prognostic significance of dipyridamole-induced ST depression in patients with normal 82Rb PET myocardial perfusion imaging.

Recent studies have shown that vasodilator-induced ischemic electrocardiographic (ECG) changes have incremental prognostic value over normal SPECT myocardial perfusion imaging (MPI) and identify patients at higher risk for cardiac events. The prognostic value of vasodilator-induced ischemic ECG changes in the setting of normal PET MPI has yet to be determined. We sought to determine the prognostic importance of dipyridamole-induced ischemic ECG changes in patients with normal 82Rb PET myocardial perfusion images. METHODS: Between 2000 and 2003, 2,029 consecutive patients undergoing dipyridamole stress 82Rb PET at the University of Ottawa Heart Institute were evaluated. Patients with normal PET MPI and interpretable ECGs were enrolled. Electrocardiograms were assessed for ST depression or elevation and patients were categorized into those with and without dipyridamole-induced ischemic ECG changes. Images were graded using the 17-segment model. Follow-up information was obtained by telephone interview, from hospital records, or from treating physicians. All cardiac events (cardiac death, nonfatal myocardial infarction [MI], percutaneous coronary intervention, coronary artery bypass grafting, or angiography) were verified with hospital records. RESULTS: Of the 629 enrolled patients with normal PET MPI, 72 patients had dipyridamole-induced ischemic ECG changes. There was no significant difference between the 2 groups in the combined endpoint (cardiac death, nonfatal MI, and revascularization) at follow-up (mean +/- SD, 27.1 +/- 13 mo). There were no cardiac deaths in either group. One (1.4%) patient with ischemic ECG changes had a nonfatal MI (0.6% annual event rate). Two (2.8%) patients with ischemic ECG changes required revascularization compared with 11 (2.0%) in the nonischemic ECG group. CONCLUSION: Normal 82Rb PET confers an excellent prognosis regardless of dipyridamole-induced ST depression.     

Quantification of myocardial ischemia and infarction with single photon emission computed tomography

To evaluate the feasibility of 201Tl single photon emission computed tomography (SPECT) for quantitative detection of myocardial infarction and ischemia, scintigraphic studies were related to angiographic findings. In study A infarct sizes with SPECT were compared with the angiographic infarct sizes of 30 patients. A linear correlation was found for the % infarct of the left ventricular circumference between both methods (r = 0.73; P less than 0.001; mean infarct size 20.7% +/- 10.5% (angio) vs 19.8% +/- 12.9% (SPECT), mean +/- SD). Furthermore, a significant inverse correlation between scintigraphic infarct size and left ventricular ejection fraction (r = -0.87, P less than 0.001) was obtained. In study B exercise/rest 201Tl SPECT was used for quantification of myocardial ischemia. Forty-three patients underwent both stress 201Tl SPECT and biplane exercise left ventriculography. Ischemia was expressed as % defect size of the left ventricular circumference. Sensitivity and specificity for detection of ischemia were 96% and 100% respectively with stress SPECT. Extent of myocardial ischemia correlated significantly with both methods (r = 0.63; SPECT defect = 1.0 angiographic ischemia +2%; P less than 0.001). The regression followed the line of identity and the mean sizes of ischemia were identical (SPECT 12.2 +/- 7.6% vs 14.6 +/- 12.4% ventriculography, mean +/- SD) demonstrating the agreement of both methods. However, there was some intraindividual variance between the scintigraphic and the angiographic study. The sensitivity and specificity in single regions with SPECT were lower compared to the global test results.(ABSTRACT TRUNCATED AT 250 WORDS)