Prognostic value of myocardial perfusion tomographic imaging in patients after percutaneous transluminal coronary angioplasty

PURPOSE: The authors assessed the prognostic value of stress myocardial perfusion tomographic imaging (SPECT) in patients with recurrent angina or inconclusive results of exercise electrocardiographic tests after successful percutaneous transluminal coronary angioplasty (PTCA). MATERIALS AND METHODS: After PTCA, 70 patients (54 men, 16 women; 41 after myocardial infarction; mean age, 56 +/- 9 years) underwent TI-201 or Tc-99m sestamibi SPECT studies. SPECT patterns were divided into normal (n = 25), fixed defects (n = 15), and reversible or combined fixed plus reversible defects (n = 30). A cardiac event was defined as either cardiac death, nonfatal myocardial infarction, or unstable angina requiring further revascularization. RESULTS: During an average follow-up of 25 +/- 10 months, two patients had severe outcomes (one cardiac death and one nonfatal myocardial infarction), and revascularization was required in 13 patients. In patients with normal SPECT or fixed defects, the annual event rate was low (1.2%), with only one revascularization. In patients with reversible or combined defects, the annual event rate was significantly greater (22.4%; chi square = 17.32, P = 0.00003). CONCLUSIONS: Normal perfusion or fixed defects predict a benign prognosis in patients after successful PTCA. The presence of stress-induced reversible defects appears to be the best predictor of future cardiac events.     

15-Year outcome after normal exercise 99mTc-sestamibi myocardial perfusion imaging: What is the duration of low risk after a normal scan?

Objective

The goal of this study was to evaluate the very long-term outcome after normal exercise ^99mTc-sestamibi myocardial perfusion single-photon emission computed tomography (SPECT). Exercise ^99mTc-sestamibi SPECT is widely used for risk stratification, but data on very long-term outcome after a normal test are scarce.

Methods

A consecutive group of 233 patients (122 men, mean age 54?±?12?years) with known or suspected coronary artery disease (CAD) underwent exercise ^99mTc-sestamibi SPECT and had normal myocardial perfusion at exercise and at rest. Follow-up endpoints were all-cause mortality, cardiac mortality, nonfatal myocardial infarction, and coronary revascularization. Predictors of outcome were identified by Cox proportional hazard regression models using clinical and exercise testing variables.

Results

During a mean follow-up of 15.5?±?4.9?years, 41 (18%) patients died, of which 13 were cardiac deaths. A total of 18 (8%) patients had a nonfatal myocardial infarction, and 47 (20%) had coronary revascularization. The annualized event rates for all-cause mortality, cardiac mortality, cardiac mortality/nonfatal infarction, and major adverse cardiac events were, respectively, 1.1%, 0.3%, 0.7%, and 1.8%. Multivariate analysis demonstrated that the variables age, male gender, diabetes, diastolic blood pressure at rest, rate pressure product at rest, peak exercise heart rate, and ST segment changes were independent predictors of major adverse cardiac events.

Conclusion

Patients with suspected or known CAD and normal exercise ^99mTc-sestamibi myocardial perfusion SPECT have a favorable 15-year prognosis. Follow-up should be closer in patients with known CAD, and/or having clinical and exercise parameters indicating higher risk status.     

Long-term prognosis after a normal exercise stress Tc-99m sestamibi SPECT study

BACKGROUND: Patients with a normal stress technetium 99m sestamibi study were shown to have a favorable outcome at intermediate-term follow-up. However, long-term survival has not been studied. The aim of this study was to evaluate the incidence and predictors of mortality and cardiac events at long-term follow-up after a normal exercise stress sestamibi study.Methods and results We studied 218 patients (mean age, 53 +/- 10 years, 108 men) who had normal myocardial perfusion assessed by Tc-99m sestamibi single photon emission computed tomography at rest and during symptom-limited bicycle exercise stress test. Endpoints during a follow-up period of 7.4 +/- 1.8 years were hard cardiac events (cardiac death and nonfatal myocardial infarction) and all-cause mortality. During follow-up, 13 patients died of various causes (cardiac death in 1 patient). Ten patients had nonfatal myocardial infarction (a total of 11 hard cardiac events). By multivariate analysis, independent predictors of cardiac events were history of coronary artery disease (chi(2) = 5, P =.03) and lower exercise heart rate (chi(2) = 12, P =.001). Independent predictors of all-cause mortality were age (chi(2) = 4, P =.05) and exercise heart rate (chi(2) = 5, P =.03). The annual mortality rate was 0.6% in the first 5 years and 1.8% between the sixth and eighth years. The annual hard cardiac event rate was 0.7% in the first 5 years and 1.5% between the sixth and eighth years. Receiver operating characteristic curves identified an exercise heart rate lower than 130 beats/min as the cutoff value that separated patients with regard to their risk for mortality and hard cardiac events. CONCLUSIONS: It is concluded that the annual mortality and cardiac event rate is less than 1% during 5-year follow-up after a normal exercise sestamibi study. Therefore repeated testing would not be required unless there is a change in symptoms. Follow-up should be closer in patients with a history of coronary artery disease and in those who fail to achieve an exercise heart rate of 130 beats/min or greater.     

Systematic review of the prognostic effectiveness of SPECT myocardial perfusion scintigraphy in patients with suspected or known coronary artery disease and following myocardial infarction

OBJECTIVES: In patients with suspected or known coronary artery disease (CAD), or following myocardial infarction (MI), assessing the degree of ischaemia is important from a prognostic and therapeutic point of view. Single photon emission computed tomography (SPECT) myocardial perfusion scintigraphy (MPS) is a non-invasive technique that allows the presence, location and extent of ischaemia to be determined. The aim of this systematic review was to assess the prognostic effectiveness of SPECT MPS. METHODS: We sought prognostic studies involving SPECT, exercise tolerance testing (ETT) and/or coronary angiography (CA) in people with suspected or known CAD, or following MI. Outcomes included cardiac death, non-fatal MI and revascularization. We searched the following databases: MEDLINE, PREMEDLINE, EMBASE, BIOSIS, Science Citation Index, the Cochrane Library, the Health Management Information Consortium and the Health Technology Assessment Database. RESULTS: Twenty-one observational studies enrolling 53,762 people reported the general prognostic value of SPECT MPS. In multivariate analysis, SPECT MPS variables yielded both independent and incremental value to combinations of clinical, ETT and angiographic variables in predicting cardiac death or non-fatal MI. Three comparative studies reported lower revascularization rates following a SPECT MPS-CA strategy (6-21%) compared with direct CA (16-44%). Four observational studies enrolling 2106 people reported the prognostic value of SPECT for patients following MI. In multivariate analysis including clinical history, ETT, SPECT MPS and angiographic variables, strategies involving SPECT MPS provided independent and incremental prognostic performance in predicting future cardiac events. CONCLUSIONS: SPECT MPS provides important additional information to that from ETT and/or CA that helps to risk-stratify patients with suspected or known CAD or following MI, enabling them to be managed more appropriately. Increasing the use of strategies involving SPECT MPS may identify lower risk patients for whom invasive CA might be avoided.     

Risk stratification of patients after myocardial revascularization by stress Tc-99m tetrofosmin myocardial perfusion tomography

BACKGROUND: The aim of this study was to assess the incremental prognostic value of stress technetium 99m tetrofosmin imaging after myocardial revascularization. METHODS AND RESULTS: We studied 381 patients (aged 60 +/- 10 years, 270 men), 4.5 +/- 3.2 years after myocardial revascularization (coronary artery bypass grafting in 201 patients and percutaneous coronary intervention in 180 patients), who underwent exercise or dobutamine stress tetrofosmin single photon emission computed tomography. Events during a mean follow-up period of 3.5 +/- 1.4 years were cardiac death in 22 patients, nonfatal myocardial infarction in 11 patients (33 hard cardiac events), and late revascularization in 50 patients. There was no incidence of hard cardiac events in the 100 patients with normal perfusion. Hard cardiac events occurred in 19% of patients with reversible perfusion abnormalities and in 4% of patients without them (P <.01). The incidence of hard cardiac events was similar in patients with and without angina before stress testing (17/197 [8.6%] vs 16/184 [8.7%]). In a multivariate analysis model, predictors of cardiac death were stress rate pressure product and abnormal perfusion. Reversible perfusion abnormalities were independently associated with the composite endpoints of cardiac death, nonfatal myocardial infarction, and late revascularization. In an incremental multivariate analysis model, an abnormal scan was additive to clinical data in the prediction of hard cardiac events (model chi(2) = 17 vs 11, P <.01). CONCLUSION: Stress Tc-99m tetrofosmin myocardial perfusion imaging provides independent prognostic information for the prediction of cardiac events after myocardial revascularization. Symptoms are not predictive of outcome, and therefore asymptomatic patients should not be deferred from stress testing. A normal study identifies a very low-risk population in whom no further intervention is required.     

Increased prognostic value of combined myocardial perfusion SPECT imaging and the quantification of lung Tl-201 uptake

PURPOSE: The authors wanted to identify those patients assessed by exercise SPECT in whom the quantification of lung Tl-201 uptake helps to evaluate disease prognosis. METHODS: One hundred forty-nine patients (114 men, 35 women; 74 after myocardial infarction [MI]; mean age, 54 +/- 9 years) underwent exercise Tl-201 SPECT. The SPECT patterns were divided into normal (n = 45), fixed defects (n = 29), and inducible ischemia (n = 75). Anterior planar imaging was performed before SPECT acquisition to calculate the lung-to-heart ratio (L:H). RESULTS: During an average follow-up of 20 +/- 9 months, eight patients had died of cardiac causes and 13 patients experienced nonfatal MIs. Among the 45 patients with normal perfusion, no cardiac event was observed and the L:H ratio was not helpful for risk stratification. In 29 patients with fixed defects, four cardiac deaths occurred (all in patients with L:H ratios >0.5; annual event rate, 21.1% for L:H ratios >0.5 compared with 0% for L:H ratios <0.5; chi-square = 4.07, P < 0.05). Among the 75 patients with ischemia, 4 died and 13 had nonfatal MIs (annual event rate, 15.4% for L:H ratios >0.5 compared with 13% for L:H ratios <0.5; P = NS). CONCLUSIONS: These findings suggest a benign prognosis in patients with normal SPECT (regardless of the L:H ratio). Conversely, all patients with ischemia are at high risk for future cardiac events. Quantification of the Tl-201 lung uptake seems to be valuable in evaluations of disease prognosis, especially in patients with fixed defects.     

Prognostic value of combined assessment of regional left ventricular function and myocardial perfusion by dobutamine and rest gated SPECT in patients with uncomplicated acute myocardial infarction.

Gated SPECT allows combined assessment of regional myocardial perfusion and left ventricular function. The aim of this study was to address the prognostic value of gated SPECT performed during dobutamine stress testing and during rest on patients with acute myocardial infarction treated with thrombolysis. METHODS: Eighty-eight consecutive patients with uncomplicated acute myocardial infarction who underwent predischarge (3-7 d after admission) dobutamine (5-40 microg/kg of body weight per minute in 3-min dose increments) and rest gated (99m)Tc-sestamibi SPECT were followed for a mean of 48 mo (range, 4-64 mo). RESULTS: Eighteen cardiac events (8 cardiac deaths and 10 nonfatal myocardial infarctions) occurred. Ischemia at dobutamine SPECT imaging (summed difference score or=>or= 1) was present in 60% of the patients. In patients without ischemia, there was a lower event rate (11%), compared with patients with mild ischemia (18%) and moderate-to-severe ischemia (40%) (P < 0.05). Patients with events showed also a higher summed difference score, compared with patients without events (2.3 +/- 1.6 vs. 1.3 +/- 1.6, P < 0.05). Independent predictors of events were the number of segments with preserved (99m)Tc-sestamibi uptake at rest and the number of akinetic or dyskinetic segments with preserved (99m)Tc-sestamibi uptake and preserved wall thickening (global chi(2) of the model, 13.6; P < 0.01). The assessment of the incremental prognostic value of variables added sequentially showed that the addition of the summed difference score added information to perfusion status at rest (P < 0.05). Combined assessment of regional myocardial perfusion and left ventricular function at rest further improved the model (P < 0.05). CONCLUSION: The present study indicated that predischarge (99m)Tc-sestamibi gated SPECT gives prognostic information on patients recovering from acute myocardial infarction. Patients with preserved systolic wall thickening should be regarded as a high-risk subgroup, requiring closer follow-up for appropriate treatment.     

Incremental prognostic value of dobutamine–atropine stress 99mTc-tetrofosmin myocardial perfusion imaging for predicting outcome in diabetic patients with limited exercise capacity

Purpose This study assessed the incremental value of dobutamine stress ^99mTc-tetrofosmin single-photon emission computed tomography (SPECT) for the prediction of cardiac events in diabetic patients with limited exercise capacity.Methods The study population comprised 125 consecutive diabetic patients (mean age 61±9 years, 61% men) who were unable to perform an exercise test and underwent dobutamine ^99mTc-tetrofosmin SPECT. Follow-up was successful in 124 (99%) patients. Three patients who underwent early revascularisation (within 60 days) were excluded. End-points during follow-up were cardiac death and non-fatal myocardial infarction.Results An abnormal scan (with the presence of reversible or fixed perfusion defects) was observed in 76 (63%) patients. During the follow-up (3.4±1.5 years), 36 patients died (19 cardiac deaths) and four patients had non-fatal myocardial infarction. Cardiac death occurred in one of 49 (2%) patients with a normal myocardial perfusion study and in 18 of 75 (24%) patients with an abnormal study (p<0.001). Abnormal scan was incremental to the clinical parameters in predicting cardiac death (²=48 vs 39, p<0.05) and hard cardiac events (²=50 vs 43, p<0.05).Conclusion Dobutamine stress ^99mTc-tetrofosmin SPECT provides prognostic information additional to clinical data for the prediction of cardiac death and hard cardiac events in diabetic patients unable to perform an exercise test.     

Risk stratification among diabetic patients undergoing stress myocardial perfusion imaging

Background

Previous studies have suggested that diabetic patients undergoing single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) are at greater risk for cardiac events than non-diabetic patients with both normal and abnormal imaging results. However, the impact of stress modality on outcomes in this patient group has not been examined.

Methods

The data on all patients undergoing exercise stress or vasodilator stress SPECT MPI from 1996 to 2005 were reviewed. After excluding patients based on our predefined criteria, we subcategorized the study population into diabetic patients and non-diabetic patients. Among the diabetic patients, we identified patients with known coronary artery disease (CAD) and no known CAD. All studies were interpreted using the 17-segment ASNC model. The presence, extent, and severity of perfusion defects were calculated using the summed stress score (SSS), and patients were classified into normal (SSS < 4), mildly abnormal (SSS 4-8), and moderate-severely abnormal (SSS > 8) categories. The annualized cardiac event rate including cardiac death and non-fatal myocardial infarction was calculated over a mean follow-up period of 2.4 ± 1.4 years with a maximum of 6 years.

Results

The cardiac event rate was statistically significantly lower in diabetic patients undergoing exercise stress MPI when compared to the diabetic patients undergoing pharmacological stress MPI across all three perfusion categories (1.3% vs 3.4%, 2.3% vs 5.7%, 4.2% vs 10.7%, respectively). Diabetic patients with no known CAD, who underwent exercise stress MPI had significantly lower cardiac events across all three perfusion categories as compared to the remainder of the diabetic population. Ability to perform exercise stress test was the strongest multivariate predictor of favorable outcome, whereas ejection fraction < 50%, abnormal perfusion imaging on SPECT MPI, and increasing age stood out as independent predictors of adverse outcome in the diabetic patients. Within the abnormal perfusion category, the annualized cardiac event rate among patients undergoing exercise stress SPECT MPI was not statistically different between the diabetic and non-diabetic cohorts.

Conclusion

Diabetic patients undergoing exercise SPECT MPI have a significantly better prognosis than those undergoing pharmacological stress, more similar to patients without diabetes. In patients with diabetes exercise stress test MPI identifies low risk patients and provides precise risk stratification.     

Postexercise lung uptake of 99mTc-sestamibi determined by a new automatic technique: validation and application in detection of severe and extensive coronary artery disease and reduced left ventricular function.

This study validated a new automatic algorithm for assessment of lung-to-heart ratio (L/H) of radiotracers in myocardial perfusion SPECT and assessed the diagnostic value of (99m)Tc-sestamibi L/H after exercise. METHODS: The new technique extracts a left ventricular region of interest (ROI) from a summed anterior projection image and generates a lung ROI by reshaping and translating the left ventricular ROI. This algorithm was applied to 230 patients who underwent exercise (99m)Tc-sestamibi SPECT (gated SPECT, n = 88) with first-pass ventriculography. Normal values were established in 26 patients in whom the likelihood of coronary artery disease (CAD) was 5% or less. An abnormality threshold for detecting severe and extensive CAD was defined in a subgroup of 109 patients who underwent coronary angiography and was validated in a prospective group (n = 72). RESULTS: The success rate of the automatic algorithm was 97%. Excellent correlation was found between automatic and manual L/H values (r = 0.95; P < 0.001). The mean L/H was higher in patients with a peak exercise ejection fraction (EF) less than 40% versus 40% or more (0.51 +/- 0.07 versus 0.43 +/- 0.05, P < 0.001) and in patients with a poststress EF less than 40% versus 40% or more (0.50 +/- 0.07 versus 0.44 +/- 0.06, P < 0.01). A threshold of L/H greater than 0.44 yielded a sensitivity and specificity of 63% and 81%, respectively, for identifying severe and extensive CAD in the prospective group and a sensitivity of 86% in identifying stenosis of 90% or more in the proximal left anterior descending artery. CONCLUSION: The new automatic algorithm for assessing L/H correlated well with manually derived L/H for (99m)Tc-sestamibi as well as (201)TI SPECT. An increased postexercise (99m)Tc-sestamibi L/H adds significant diagnostic value to study myocardial perfusion SPECT as a marker of severe and extensive CAD and reduced ventricular function.     

18F-FDG／99Tcm—MIBI双核素心肌断层显像检测急性心肌梗死患者存活心肌

目的探讨18F-FDG／99Tcm-MIBI双核素心肌断层显像检测AMI患者存活心肌,评价该方法对心功能改善及预后判断的价值。方法98例[男87例,女11例,年龄（58±11）岁]确诊为AMI患者,均行18F-FDG／99Tcm-MIBI双核素心肌断层显像,采用半定量方法将心肌分成9个节段,并评分,放射性轻度减低=1分,明显减低=2分,缺损=3分。根据灌注和代谢显像情况,两者不匹配视为存活心肌,两者匹配为心肌无存活。治疗前后行超声心动图检查观察LVEF变化;所有患者进行随访,统计心脏事件发生率,比较再血管化治疗和药物治疗患者的心脏事件发生率差别。频数的比较采用x2检验。结果心肌存活组患者27例,接受冠状动脉再血管化和药物治疗者分别为27和10例;心肌无存活组61例,接受冠状动脉再血管化治疗和药物治疗者分别为35和26例。无论是心肌存活组还是心肌无存活组,再血管化治疗和药物治疗相比较,心功能明显改善（LVEF提高≥10％）的患者比例差异均无统计学意义（心肌存活组：矿=0．509,P〉0．05;心肌无存活组：x2=0．035,P〉0．05）。平均随访时间为（234-11）个月,心肌存活组接受药物治疗患者的心脏事件发生率明显高于接受再血管化治疗的患者（50．0％和14．8％,X2=4．91,P〈0．05）;在心肌无存活组,药物治疗患者的心脏事件发生率也同样明显高于再血管化治疗（30．7％和5．7％,x2=6．83,P〈0．05）。结论利用18F-FDG／99Tcm-MIBI双核素心肌断层显像检测AMI患者存活心肌,以判断心功能改善和预后,具有一定价值,同时也有局限性,还需要大规模前瞻性研究进一步证实。     

Prognostic implications of combined prone and supine acquisitions in patients with equivocal or abnormal supine myocardial perfusion SPECT.

Although acquisition of (99m)Tc-sestamibi myocardial perfusion SPECT (MPS) with the patient in the prone position is commonly used to minimize attenuation artifacts, the impact of combined prone and supine imaging on the prognostic evaluation of coronary artery disease (CAD) has not been determined. The prognostic implications of MPS obtained in both prone and supine positions in patients with perfusion defects on supine MPS were evaluated. METHODS: We studied 3,834 patients who were monitored for 24.2 +/- 6.0 mo after rest (201)Tl/stress (99m)Tc-sestamibi MPS acquired during 1994-1995, when prone acquisition was performed only in patients with inferior wall perfusion defects that might represent attenuation or motion artifact. RESULTS: During follow-up, there were 132 hard events (cardiac death or myocardial infarction) and 375 total events (hard events or late myocardial revascularization). Overall, patients who underwent prone and supine acquisitions had similar characteristics to those who underwent supine-only imaging, with the exception of being more commonly male. In multivariable analysis, there were similar independent predictors for hard events and total events; the type of acquisition (prone and supine or supine-only) was not a significant predictor of either of these outcome events. After risk adjustment, the predicted event rates were nearly identical for patients undergoing prone and supine compared with supine-only studies. Both observed and predicted hard event rates of patients with normal prone and supine versus supine-only imaging were very low (observed, 0.7%/y and 0.5%/y, respectively; predicted, 1.5% over 24 mo for both). There was no reduction in the higher rates of events associated with abnormal scan results with the combination of prone and supine imaging. CONCLUSION: Patients with inferior wall defects on supine MPS that are not present on prone MPS have a low risk of subsequent cardiac events, similar to that of patients with normal supine-only studies.     

Incremental prognostic value of <Superscript>99m</Superscript>Tc-tetrofosmin myocardial SPECT after percutaneous coronary intervention

Objective  Percutaneous transluminal coronary angioplasty is a well-established therapeutic method in selected patients with coronary artery disease. The aim of this study was to assess the incremental prognostic value of technetium-99m (^99mTc)-tetrofosmin myocardial gated-single- photon emission computed tomography (SPECT) in asymptomatic patients after coronary artery stenting. Methods  A total of 246 consecutive patients (aged 55.5 ± 8.2 years, 182 men) participated in the study with a median follow-up of 9.5 years (interquartile ra 5.8–10.5 years). All patients underwent exercise gated-SPECT myocardial imaging within 5–7 months. Myocardial scintigrams were performed using 99mTctetrofosmin, and were evaluated calculating the summed stress score (SSS), summed rest score (SRS), and summed difference score (SDS) indexes. Cardiovascular death and non-fatal myocardial infarction were considered as hard cardiac events, and late revascularization (>3 months after myocardial SPECT) procedures as soft events. Receiver-operating characteristic (ROC) analysis was used to test the prognostic ability of SSS and SDS for cardiac events. Cox proportional hazards models were used to evaluate the incremental value of SPECT variables. Results  Cardiac death occurred in 12 (4.9%) patients and non-fatal myocardial infarction in 20 (8.1%) patients. In addition, 60 (24.4%) patients underwent a late revascularization procedure. Using ROC analysis the optimal cut-offs of SSS (AUC = 0.94; 95% CI 0.92–0.97) and SDS (AUC = 0. 76; 95% CI 0.70–0.82) for the prediction of cardiac events were 10 and 1.7, respectively. Multiple Cox regression analyses revealed that SSS > 10 (HR = 24.2; 95% CI 7.44–78.79) and SDS > 1.7 (HR = 2.72; 95% CI 1.23–6.00) provided incremental prognostic value over clinical and exercise test data for the composite end points of any cardiac event. Conclusions   ^99mTc-tetrofosmin myocardial gated- SPECT, performed 6 months post-percutaneous coronary intervention (PCI), provides incremental prognostic information for the prediction of cardiac events in asymptomatic patients after PCI.     

The prognostic value of ECG-gated SPECT imaging in patients undergoing stress Tc-99m sestamibi myocardial perfusion imaging

BACKGROUND: The ability of stress radionuclide myocardial perfusion imaging to predict adverse cardiac events is well accepted. As left ventricular systolic function has also been shown to be an important prognostic indicator, the objective of this study was to determine whether electrocardiography (ECG)-gated single photon emission computed tomography (SPECT) functional data add additional power. METHODS AND RESULTS: In this study 3207 patients who underwent stress myocardial perfusion imaging with ECG gating, without early (相似文献   

Prognostic value of stress-gated 99m-technetium SPECT myocardial perfusion imaging: Risk stratification of patients with multivessel coronary artery disease and prior coronary revascularization

Background

This study assessed the prognostic value of stress-gated 99mTc-sestamibi myocardial perfusion SPECT (MPS) in patients with multivessel coronary artery disease (CAD) and prior revascularization according to the presence and severity of ischemia.

Methods and Results

We studied the outcome of 472 patients with multivessel CAD and prior revascularization (coronary angioplasty, 290 patients; bypass surgery, 182 patients), who underwent exercise or dipyridamole 99mTc-sestamibi MPS for evaluation of ischemia. Visual scoring of perfusion images used 20 segments and a 5-point scale. Gated post-stress EF was automatically calculated. Endpoints included hard events: cardiac death (CD) and nonfatal myocardial infarction (MI). During a mean follow-up of 3.0 ± 1.0 years, 37 hard events occurred, including CD in 15 (3%) and MI in 22 (5%) patients. In a risk-adjusted multivariable Cox model, a history of prior MI, diabetes, abnormal MPS, moderate-to-severe ischemia, and post-stress EF <35% were important predictors of cardiac events. Four-year risk-adjusted survival was 97.9% for normal MPS, 87.3% for abnormal MPS with ischemia, and 82.1% for moderate-to-severe ischemia.

Conclusions

Among patients with previous coronary revascularization, stress-gated 99mTc-sestamibi MPS provides prognostic information for the prediction of cardiac events. A normal perfusion scan confers an excellent prognosis and an exceedingly low hard event rate (<1%/year). The presence of moderate-to-severe ischemia or a post-stress EF <35% identifies patients at highest risk of subsequent cardiac events.     

12-Year outcome after normal myocardial perfusion SPECT in patients with known coronary artery disease

Background

Previous studies have reported a favorable outcome of patients with normal single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI). The aim of this study was to assess the very long-term prognosis of patients with known coronary artery disease (CAD) and normal SPECT MPI results.

Methods

The population consisted of 266 patients with known CAD (defined as a healed myocardial infarction and/or a previous coronary revascularization), who underwent exercise bicycle or dobutamine-atropine stress SPECT MPI and had normal perfusion during stress and at rest. End points during follow-up were all-cause mortality, cardiac mortality, and nonfatal myocardial infarction. Univariate and multivariate analyses were performed to identify predictors of long-term outcome.

Results

Follow-up was completed in 261 (98%) patients. During a median follow-up of 12 years, 94 (36%) patients died, of which 26 (10%) died due to cardiac causes, and 15 (6%) had a nonfatal myocardial infarction. The annualized mortality rate was 3.1%, annualized cardiac mortality rate was 0.9%, and the annualized event rate for cardiac death and/or nonfatal infarction was 1.2%. Independent predictors of total mortality were age, diabetes mellitus, and rate-pressure product at peak stress. Independent predictors of cardiac mortality were age, male gender, and rate-pressure product at peak stress.

Conclusion

Patients with known CAD and a normal SPECT MPI study have a favorable long-term prognosis. Clinical and stress test variables can be used to identify patients with a higher risk status.     

Diagnostic efficacy of stress technetium 99m-labeled sestamibi myocardial perfusion single-photon emission computed tomography in detection of coronary artery disease among patients over age 80

Background

Because symptoms of myocardial ischemia in elderly patients are often atypical, accurate noninvasive assessment of the presence, extent, and severity of coronary artery disease (CAD) would be especially useful to avoid unnecessary catheterization or invasive intervention. This study assessed the safety and diagnostic efficacy of ^99mTc-labeled sestamibi (^99mTcsestamibi) exercise and pharmacologic myocardial perfusion single-photon emission computed tomography (SPECT) with adenosine or dipyridamole in patients age 80 years or older.

Methods and Results

Stress ^99mTc-sestamibi SPECT was performed in 75 consecutive patients who were 80 years old or older (range: 80 to 91 years) with suspected CAD and who underwent coronary angiography within 6 months of the nuclear study. Of these patients, 51 underwent a pharmacologic (adenosine=42; dipyridamole=9) stress study and 24 underwent an exercise treadmill study. A normalcy rate was derived from an additional 36 patients (ages 83±3 years) who had undergone stress ^99mTc-sestamibi SPECT and who had a relatively low likelihood (<20%) of CAD. No serious adverse events occurred during or after the exercise or the pharmacologic stress test. The overall sensitivity and specificity for detecting CAD with ≥70% stenosis was 95% (52/55) and 75% (15/20), whereas the corresponding results were 87% (55/63) and 83% (10/12) for detecting patients with ≥50% stenosis. The sensitivity and specificity for pharmacologic stress ^99mTc-sestamibi SPECT were 95% (35/37) and 71% (10/14) for detecting ≥70% stenosis, and 86% (37/43) and 75% (6/8) for detecting CAD with ≥50% stenosis. The sensitivity and specificity of treadmill testing were 94% (17/18) and 83% (5/6) in detecting CAD with stenosis ≥70% and 90% (18/20) and 100% (4/4) in detecting CAD with stenosis ≥50%. The normalcy rate among the low likelihood patients was 83% (30/36). The accuracy of stress sestamibi testing was similar for patients with or without angina.

Conclusions

Our findings suggest that exercise or pharmacologic myocardial perfusion SPECT with ^99mTc-sestamibi is safe and diagnostically accurate for CAD detection in very elderly patients, irrespective of symptoms. Pharmacologic myocardial perfusion SPECT with adenosine or dipyridamole appears to be a valuable alternative to treadmill stress in very elderly patients incapable of performing adequate exercise.     

Clinical outcome of patients with previous myocardial infarction and left ventricular dysfunction assessed with myocardial (99m)Tc-MIBI SPECT and (18)F-FDG PET.

Myocardial viability was assessed by (99m)Tc-methoxyisobutylisonitrile (MIBI) SPECT and (18)F-FDG PET to evaluate the prognosis and treatment strategy of patients with myocardial infarction (MI) and left ventricular (LV) dysfunction. METHODS: One hundred twenty-three consecutive patients with previous MI and LV dysfunction (LV ejection fraction [EF], 35% +/- 6% [mean +/- SD]) who underwent (99m)Tc-MIBI SPECT and FDG PET were followed-up for 26 +/- 10 mo (mean +/- SD). Distributions of the 2 radiotracers in myocardial segments were classified into 2 patterns: myocardial perfusion-metabolism mismatch (MM) and match (M). LV EF and LV end-diastolic diameter (EDD) were measured by echocardiography at baseline, 3 mo (Pos1), and 6 mo (Pos2) after revascularization. Cardiac death, acute MI, unstable angina, and late revascularization (>3 mo) experienced by the patients during follow-up were defined as cardiac events. RESULTS: Sixty-seven patients underwent revascularization and 56 patients were treated medically. Of the 72 patients with > or =2 MM segments, 42 underwent revascularization (group A1) and 30 were treated medically (group A2). Of the 51 patients with <2 MM segments, 25 underwent revascularization (group B1) and 26 were treated medically (group B2). The 4 groups had similar baseline characteristics and rest LV EF. After revascularization, EF (mean +/- SD) increased in group A1 from 36% +/- 5% to 44% +/- 8% (P < 0.0001) in Pos1 and to 51% +/- 9% (P < 0.0001) in Pos2. EDD (mean +/- SD) decreased from 62 +/- 8 mm to 56 +/- 5 mm (P < 0.001) in Pos1 and to 55 +/- 5 mm (P < 0.001) in Pos2. However, EF and EDD were unchanged in group B1 (P > 0.05). During the follow-up, 22 patients (17.9%) suffered from cardiac events, including 11 cardiac deaths, 4 acute MI, 6 late coronary artery bypass grafting, and 1 unstable angina pectoris. The cardiac event rate in group A2 (50%) was significantly higher than that of groups A1 (2.4%; chi(2) = 23.08; P < 0.0001), B1 (12%; chi(2) = 8.94; P = 0.003), and B2 (11.5%; chi(2) = 9.45; P = 0.002). CONCLUSION: Assessment of myocardial viability using hybrid (99m)Tc-MIBI SPECT and FDG PET can predict the clinical outcome and is helpful to decision making in the treatment strategy of patients with MI and LV dysfunction. Revascularization can improve the LV function and clinical outcome of patients with >2 viable myocardial segments.     

The (F)utility of the thallium-201 quantitative lung/myocardial ratio in the detection of coronary artery disease

Exercise-induced increases in pulmonary uptake of thallium-201 (201Tl) have been associated with exercise-induced myocardial dysfunction. To evaluate this phenomenon more replicably, a quantitative semi-automated computer program was used to generate, from anterior exercise and delayed views, lung-myocardial ratios (LMR) of 201Tl uptake in 78 patients [40 normal, 38 with coronary artery disease (CAD)]. Patients with CAD had a significantly higher mean exercise lung myocardial ratio (EXLMR) than normals (30.8 vs. 27.3; P less than 0.003). In patients with adequate exercise (greater than or equal to 85% of an age-adjusted maximal heart rate), the EXLMRs of CAD patients were significantly higher than those of normals (29.7 vs. 25.5; P = 0.003). However, this difference between CAD and normal patients was not apparent in a patient subgroup with submaximal exercise levels (less than 85% of an age-adjusted maximal heart rate). In both normal and CAD patients, EXLMR decreased with increasing exercise levels (r = -0.555; P = 0.007). In patients with 201Tl scans lacking visually defined perfusion defects (visually normal), an elevated LMR detected 60% of CAD cases with 81% specificity. A considerably elevated EXLMR in patients achieving adequate exercise should suggest the presence of CAD, even if there are no visually apparent cardiac perfusion defects. With submaximal exercise, however, the EXLMR is not a useful discriminator between CAD patients and normals.     

Long-term survival of patients with viable and nonviable aneurysms assessed by 99mTc-MIBI SPECT and 18F-FDG PET: a comparative study of medical and surgical treatment

The prognostic value of myocardial viability assessment on left ventricular (LV) aneurysms remains undetermined. We aimed, first, to evaluate the long-term survival benefit of assessing the viability of the aneurysmal myocardium in patients with ischemic cardiomyopathy and, second, in the revascularization subgroup, to compare the short-term effects on LV function and clinical symptoms in patients treated by revascularization alone or by revascularization plus aneurysmectomy. METHODS: Seventy consecutive patients with an LV aneurysm who underwent 99mTc-sestamibi SPECT and 18F-FDG PET were followed up for a median of 6.8 y (range, 0.1-8.8 y). Only cardiac death during follow-up served as the endpoint. Patients were classified into 4 groups by aneurysmal viability and by treatment strategy (medical or surgical). Further, the effects of aneurysmectomy on LV function at 3 mo were evaluated by an analysis of revascularized patients grouped by aneurysmal viability and by aneurysmectomy. RESULTS: Twenty-four patients were assigned to medical therapy, and 46 patients were assigned to surgery (18 revascularization alone and 28 revascularization plus aneurysmectomy). The annual cardiac mortality rate in patients with a viable aneurysm treated medically (n = 10) was significantly higher than that in patients with a viable aneurysm treated surgically (n = 23) (11.6% vs. 1.5%, chi2 = 12.87, P < 0.0001) and was also significant higher than that in patients with a nonviable aneurysm treated medically (n = 14) (chi2 = 4.13, P < 0.05) or surgically (n = 23) (chi2 = 10.46, P = 0.001). Multivariate analysis showed that the aneurysmal mismatch score (P = 0.003) and surgical therapy (P = 0.001) were independent predictors of cardiac death. Improvement of LV function and symptoms after revascularization (P < 0.05) was observed in patients with revascularization plus aneurysmectomy and in patients with a viable aneurysm and revascularization only. CONCLUSION: Viability in LV aneurysm in patients with ischemic cardiomyopathy was a negative independent predictor of survival. Compared with medical therapy, coronary revascularization was associated with improved long-term survival, symptoms, and LV function in patients with a viable aneurysm. These findings warrant further prospective investigations.