Resting radionuclide myocardial perfusion imaging in a chest pain center including an overnight delayed image acquisition protocol

Emergency department (ED) patients with chest pain (CP) and a nondiagnostic electrocardiogram (ECG) present difficult management decisions. The purpose of this study was to investigate the utility of resting radionuclide SPECT myocardial perfusion imaging (SPECT MPI)-including an overnight delayed image acquisition protocol-in identifying patients presenting to the ED with CP at risk for cardiac events. METHODS: Patients presenting to the ED with CP and a nondiagnostic ECG were prospectively enrolled and underwent chest pain center evaluation. All patients also underwent resting gated SPECT MPI using (99m)Tc-tetrofosmin tracer. Patients presenting on weeknights between 12 am and 6 am had tracer injection in the ED with image acquisition delayed until later in the morning. Patients were monitored for a 30-d occurrence of cardiac events. RESULTS: Over a 16-mo period, 479 patients were enrolled and completed follow-up. For the prediction of 30-d cardiac events, resting SPECT MPI demonstrated a sensitivity and a specificity of 76.9% and 92.4%, respectively. Positive and negative predictive values were 22.2% and 99.3%, respectively. Among the 3 patients with a normal perfusion scan who suffered cardiac events, all had tracer injection several hours after resolution of CP. The overnight delayed image acquisition protocol provided a negative predictive value of 100% for the 44 patients whose image acquisition was delayed until the following morning. CONCLUSION: A normal resting SPECT MPI in ED patients presenting with CP predicts a very low occurrence of 30-d cardiac events. A delayed image acquisition protocol did not decrease the accuracy of SPECT MPI. Such a protocol may be useful in increasing the availability of this imaging modality.     

The role of cardiovascular imaging techniques in the assessment of patients with acute chest pain

Chest pain is the most common presenting symptom of coronary artery disease. The assessment and appropriate management of patients with acute chest pain and non-diagnostic electrocardiograms (ECGs) remain a continuing clinical problem, with major logistic and financial implications for health-care providers. Cardiovascular imaging is at the forefront of health care, experiencing rapid changes over the recent years, particularly with the use of advanced medical technologies. Imaging techniques like acute rest myocardial perfusion imaging (MPI), echocardiography, electron beam computed tomography (CT), cardiac magnetic resonance imaging (MRI) and multi-detector CT (MDCT) have been used recently in the evaluation and triage of patients with chest pain in addition to the conventional investigations such as ECGs and cardiac biomarkers in the chest pain units. The annual potential cost savings, by incorporating the routine use of acute rest MPI in patients with low-to-moderate risk and non-diagnostic ECGs are substantial. The high negative predictive value of a normal resting MPI in patients with chest pain for myocardial infarction and future cardiac events is well established. Echocardiography is also considered to be useful but the technique is operator dependent and at present there is insufficient data to support its use. Cardiac MRI is expensive and time consuming and there is insufficient diagnostic and prognostic data to make it suitable for chest pain patients at present. There has been increasing interest in MDCT recently, especially with the advent of 64-slice CT but the sensitivity and specificity in chest pain patients are no better than MPI so far.     

Use of myocardial perfusion imaging to predict the effectiveness of coronary revascularisation in patients with stable angina pectoris

Purpose Coronary revascularisation is the treatment of choice in patients with stable angina who have significant stenoses. From a pathophysiological point of view, however, mitigation of angina is to be expected only in the presence of reversible ischaemia. Therefore it was the aim of this study to examine the effect of revascularisation on stable angina in relation to the myocardial perfusion imaging (MPI) pattern prior to intervention.Methods Three hundred and eighty-four patients (58.0±8.8 years) referred for angiography underwent MPI. Prior to MPI and at 2-year follow-up, patients were classified as having typical angina, atypical angina, non-cardiac chest pain or no pain, and the severity of chest pain was graded according to the Canadian Cardiovascular Society (CCS) criteria. The patients themselves estimated their pain on a visual analogue scale. Management was based on symptoms and angiographic findings, since the results of MPI were not communicated.Results Among the 240 patients who were not revascularised, 79% had typical or atypical angina at study entrance versus 40% at follow-up. In comparison, 93% of the 144 revascularised patients had typical or atypical angina before intervention versus only 36% at follow-up. This additional advantage of invasive therapy was present only in patients with reversible defects; revascularisation had no additional effect in patients with normal perfusion or irreversible defects. Similarly, additional, significant reductions in CCS class and visual analogue score were observed exclusively in patients with reversible defects.Conclusion In patients referred for coronary angiography owing to known or suspected stable angina, revascularisation was significantly more effective than medical treatment exclusively in patients with reversible ischaemia.This paper was presented in part (as a poster and an oral presentation) at the International Meeting: Nuclear Cardiology Today 2004, Cesena, Italy     

Acute rest myocardial perfusion imaging for chest pain

Conclusions  Rest radionuclide MPI has made a substantial impact on how patients presenting with acute chest pain are triaged in EDs. Because of the high negative predictive value and favorable prognosis of patients with acute chest pain and normal rest MPI, emergency medicine physicians feel more confident that these patients can be safely discharged. The practice of performing subsequent stress testing in patients with normal rest MPI or normal serial biomarkers has substantially improved the quality of care of patients presenting to the ED with acute chest discomfort. Patients with acute chest pain who undergo a full diagnostic workup as outlined above, including acute rest MPI, benefit from a quick and complete cardiologic evaluation. This is in contrast to the old practice of unnecessary hospitalization for several days or unfortunate discharge from the ED with an evolving acute coronary syndrome. When incorporated into clinical pathways, rest MPI has contributed to improved clinical outcomes by decreasing the number of missed myocardial infarcts, reducing unnecessary admissions, and lowering overall costs when compared with standard patient management.     

Comparison of acute rest myocardial perfusion imaging and serum markers of myocardial injury in patients with chest pain syndromes

BACKGROUND: Newer diagnostic modalities such as serum markers and acute rest myocardial perfusion imaging (MPI) have been evaluated diagnostically in patients with chest pain in the emergency department (ED), but never concurrently. We compared these two modalities in distinguishing patients in the ED with symptomatic myocardial ischemia from those with non-cardiac causes. METHODS: Serum markers and acute technetium-99m sestamibi/tetrofosmin rest MPI were obtained in 75 patients admitted to the ED with chest pain and nondiagnostic electrocardiograms. Venous samples were drawn at admission and 8 to 24 hours later for total creatine kinase, CK-MB fraction, troponin T, troponin I, and myoglobin. Three nuclear cardiologists performed blinded image interpretation. Coronary artery disease (CAD) was confirmed either by diagnostic testing or by the occurrence of myocardial infarction (MI). RESULTS: Acute rest MPI results were abnormal in all 9 patients with MI. An additional 26 patients had objective evidence of CAD confirmed by diagnostic testing. The sensitivity of acute rest MPI for objective evidence of CAD was 73%. Serum troponin T and troponin I were highly specific for acute MI but had low sensitivity at presentation. Individual serum markers had very low sensitivity for symptomatic myocardial ischemia alone. In the multivariate regression model, only acute rest MPI and diabetes were independently predictive of CAD. CONCLUSION: At the time of presentation and 8 to 24 hours later, acute rest MPI has a better sensitivity and similar specificity for patients with objective evidence of CAD when compared with serum markers.     

Vascular endothelial dysfunction is associated with reversible myocardial perfusion defects in the absence of obstructive coronary artery disease

Background  The purpose of this study was to investigate whether endothelial dysfunction contributes to abnormal myocardial perfusion imaging (MPI) observed in patients without obstructive coronary artery disease (CAD). It is unclear whether reversible MPI defects detected in the absence of obstructive CAD represent underlying vascular pathology or are false-positive MPI results. Recent evidence suggests that coronary endothelial dysfunction might play a role in the pathogenesis of these defects. Methods and Results  We prospectively recruited 36 patients with chest discomfort, reversible abnormalities on MPI, and nonobstructive or absent CAD (stenosis <50% on coronary angiography). The control group (n = 55) consisted of patients with chest discomfort and similar cardiac risk factors but with normal MPI findings. Vascular endothelial function was assessed in the brachial artery by ultrasound as the response to hyperemia and reported as percent flow-mediated dilation (FMD). Response to sublingual nitroglycerin was used as an indicator of endothelium-independent vasodilation. The patients with abnormal MPI findings and nonobstructive CAD had a significantly lower FMD (9.0% ± 7.2%), indicating endothelial dysfunction, compared with those with similar risk factors and normal MPI findings (12% ± 5.2%) (P ± .03). Baseline brachial artery size and endothelium-independent dilation were similar between groups. On multivariate analysis, only endothelial dysfunction was predictive of reversible MPI defects. Conclusions  Patients with chest pain and reversible MPI defects but without obstructive CAD have lower FMD indicative of endothelial dysfunction, as compared with similar patients with normal MPI findings. The possibility of a causal link between reversible MPI defects and endothelial dysfunction needs further exploration. Dr Soman was funded by the Herbert J. Levine Foundation Fellowship in Cardiovascular Medicine at Tufts-New England Medical Center and the Kos Pharmaceutical Fellowship in Preventive Cardiology during the course of this project.     

Prognostic value of spect myocardial perfusion imaging in patients with elevated cardiac troponin i levels and atypical clinical presentation

Background  We determined the prognostic value of myocardial perfusion imaging (MPI) in patients with atypical clinical presentations and unexpected elevation of cardiac troponin I (cTnI) levels. Methods and Results  In 156 consecutive patients with atypical presentations for acute coronary syndromes (ACS) and elevated cTnI levels undergoing MPI within 30 days, rates of all-cause mortality (100% follow-up; median follow-up, 611 days) and 6-month cardiac death and nonfatal myocardial infarction (96% follow-up; median follow-up, 167 days) were determined. The mean age of the patients was 68 ± 14 years. The majority of the study cohort (96%) was at low to intermediate clinical risk for ACS (Thrombolysis in Myocardial Infarction score for unstable angina/non-ST-segment elevation myocardial infarction < 5). The overall event rate was high, with 45 deaths (28.8%). There were 13 cardiac deaths/nonfatal myocardial infarctions in 6 months (8.3%). A normal MPI result was associated with a high event-free survival rate, whereas an abnormal MPI result was associated with a 3-fold and 7-fold higher risk of all-cause mortality and 6-month cardiac events, respectively. An abnormal MPI result was an independent predictor of all-cause death. Conclusions  In patients with cTnI elevation and a low to intermediate risk for ACS, a normal MPI result portends a good prognosis. Patients with abnormal MPI results have a higher 6-month cardiac event rate and a worse survival rate.     

Sensitivity of acute rest myocardial perfusion imaging for identifying patients with myocardial infarction based on a troponin definition

BACKGROUND: Myocardial perfusion imaging (MPI) is often used to identify low-risk chest pain patients who have myocardial infarction (MI). A recent recommendation is that patients with increased troponin levels be diagnosed as having MI. The sensitivity and characteristics of patients who have elevated troponin levels who also underwent early MPI are unknown. METHODS AND RESULTS: Patients considered at low risk for MI underwent rest gated tomographic MPI and serial marker assessment as part of a standard chest pain evaluation protocol. Patients with cardiac troponin I (cTnI) elevations were analyzed further for this study. MPI results were considered positive if there was a perfusion defect in association with abnormal wall motion or thickening. Short-axis images were divided into 17 segments and graded on a 4-point scale (0, normal; 3, high-grade or absent perfusion), and a summed rest score was derived. Of the 319 patients who had MPI and cTnI elevations, 78 had negative MPI results (sensitivity, 75%). Patients with negative MPI results had lower peak creatine kinase (CK)-MB values (15 +/- 25 ng/mL vs 45 +/- 78 ng/mL, P <.0001) and higher ejection fractions (56% +/- 15% vs 47% +/- 13%, P <.0001) and were less likely to have significant disease (55% vs 72%, P =.04) than those with positive MPI results. Increasing summed rest score was associated with larger MIs as estimated by peak CK and CK-MB values. CONCLUSIONS: Patients with negative MPI results have smaller MIs and less extensive coronary disease. MPI and cTnI offer complementary data for assessing patients with possible MI.     

Efficiency and safety of coronary CT angiography compared to standard care in the evaluation of patients with acute chest pain: a Canadian study

The optimal assessment of patients with chest pain and possible acute coronary syndrome (ACS) remains a diagnostic dilemma for emergency physicians. Cardiac computed tomographic angiography (CCTA) may identify patients who can be safely discharged home from the emergency department (ED). The objective of the study was to compare the efficiency and safety of CCTA to standard care in patients presenting to the ED with low- to intermediate-risk chest pain. This was a single-center before-after study enrolling ED patients with chest pain and low to intermediate risk of ACS, before and after implementing a cardiac CT-based management protocol. The primary outcome was efficiency (time to diagnosis). Secondary outcomes included safety (30-day incidence of major adverse cardiovascular events (MACE)) and length of stay in the ED. We enrolled 258 patients: 130 in the standard care group and 128 in the cardiac CT-based management group. The cardiac CT group had a shorter time to diagnosis of 7.1 h (IQR 5.8–14.0) compared to 532.9 h (IQR 312.8–960.5) for the standard care group (p?<?0.0001) but had a longer length of stay in the ED of 7.9 h (IQR 6.5–10.8) versus 5.5 h (IQR 3.9–7.7) (p?<?0.0001). The MACE rate was 1.6 % in the standard care group and 0 % in the cardiac CT group. In conclusion, a cardiac CT-based management strategy to rule out ACS in ED patients with low- to intermediate-risk chest pain was safe and led to a shorter time to diagnosis but increased length of stay in the ED.     

Left ventricular ejection fraction and volumes calculated from dual gated SPECT myocardial imaging with 99Tcm-MIBI.

Dual gated (DG) cardiac single photon emission computed tomographic (SPECT) studies at end-diastole (ED) and end-systole (ES) were acquired in 27 ischaemic heart disease (IHD) patients after intravenous injection of 555-740 MBq 99Tcm-MIBI. Acquisition parameters were: 180 degrees from LPO to RAO, 32 projections, 64 x 64 matrix, 75 cardiac beats per projection, 80 ms at ED and 80 ms at ES for each cardiac cycle. A computer program was developed to calculate the ED and ES left ventricular (LV) volumes and LV ejection fraction (EF). The computational approach is interactive, semi-automatic and iterative with built-in visual quality control. Short axis slices are used with corresponding ED and ES slices processed as pairs from apex to base. Left ventricular cavity pixels are identified and summed on a slice-by-slice basis. Myocardial pixels are similarly identified. The computed LVEF and ED and ES volumes have been correlated with those from contrast ventriculography (CV). The mean calculated EF for 27 patients was 53.6 +/- 10.7% from DG SPECT versus 55.3 +/- 12.1% from CV (NS). The EF linear correlation coefficient was r = 0.97.     

Performance of rest myocardial perfusion imaging in the management of acute chest pain in the emergency room in developing nations (PREMIER trial)

Background

Rest myocardial perfusion imaging (MPI) is effective in managing patients with acute chest pain in developed countries. We aimed to define the role and feasibility of rest MPI in low-to-middle income countries.

Methods and Results

Low-to-intermediate risk patients (n?=?356) presenting with chest pain to ten centers in eight developing countries were injected with a Tc-99m-based tracer, and standard imaging was performed. The primary outcome was a composite of death, non-fatal myocardial infarction (MI), recurrent angina, and coronary revascularization at 30?days. Sixty-nine patients had a positive MPI (19.4%), and 52 patients (14.6%) had a primary outcome event. An abnormal rest-MPI result was the only variable which independently predicted the primary outcome [adjusted odds ratio (OR) 8.19, 95% confidence interval 4.10-16.40, P?=?.0001]. The association of MPI result and the primary outcome was stronger (adjusted OR 17.35) when only the patients injected during pain were considered. Rest-MPI had a negative predictive value of 92.7% for the primary outcome, improving to 99.3% for the hard event composite of death or MI.

Conclusions

Our study demonstrates that rest-MPI is a reliable test for ruling out MI when applied to patients in developing countries.     

A comprehensive strategy for the evaluation and triage of the chest pain patient: A cost comparison study

BACKGROUND: Our objective was to determine the cost-effectiveness of a comprehensive, risk-based triage system, composed of multiple critical pathways, with the use of early myocardial perfusion imaging (MPI) in low-risk patients. We found previously that a chest pain evaluation system that uses MPI in low-risk patients was safe and effective, but the cost-effectiveness of this approach was not studied. METHODS AND RESULTS: We compared two groups. The Acute Cardiac Team (ACT) group (n = 874) was assigned prospectively to 1 of 4 risk levels by emergency department (ED) physicians. Level 1, 2, and 3 patients were admitted; level 4 patients were evaluated in the ED. Level 3 and 4 patients underwent ED MPI. The control group (n = 713) represented consecutive patients evaluated in the prior year according to standard care and assigned retrospectively to an ACT level based on the presenting electrocardiographic and clinical data. Record and hospital administrative data were assessed for clinical variables, outcomes, lengths of stay, and all expenses incurred within 30 days of the index visit. The baseline characteristics of the two groups were similar, including age, sex, myocardial infarction prevalence, and 30-day revascularization rates within each level or between the two groups. Mean costs per encounter were reduced for the ACT patients for each level, which was significant when all patients were compared ($5,030 +/- $7,081 vs $6,044 +/- $10,432, P =.02). Use of MPI in the low-risk patients was associated with reduced costs (level 3, $4,958 +/- $4,948 vs $5,051 +/- $7,036; level 4, $1,529 +/- $2,664 vs $1,794 +/- $6,854) and was associated with a significantly lower angiography rate and shorter length of stay. CONCLUSIONS: Implementation of a comprehensive strategy for chest pain evaluation and triage reduced overall costs for patients with chest pain on presentation. Acute MPI in the ED setting did not increase net cost.     

Dobutamine-induced chest pain does not predict ischemic findings on myocardial perfusion imaging

Background. Chest pain occurs frequently during dobutamine stress testing and is commonly attributed to ischemia. However, the pathophysiologic significance of dobutamine-induced chest pain is uncertain. The purpose of this study is to explore the correlation between dobutamine-induced chest pain and evidence of ischemia on myocardial perfusion imaging (MPI). Methods and Results. This study included 1608 patients who underwent dobutamine stress MPI at the Mid America Heart Institute (Kansas City, Mo) and were analyzed retrospectively. Patients were divided into those with chest pain during dobutamine infusion versus those without it. Multivariate and χ ² analyses were conducted to explore the relationship between chest pain and ischemic changes on MPI. Of 1608 patients, 208 (13%) had chest pain with dobutamine whereas 1400 (87%) did not. MPI ischemia was seen in 47% of patients with chest pain and 43% without chest pain (P=.28). Chest pain was not any more predictive of ischemia when analyzed separately by gender (P=.31). Multivariate analysis did not identify chest pain as a predictor of ischemia (P=.19). Significant predictors of scintigraphic ischemic changes were age (P=.001), gender (P<.0001), smoking (P=.0149), and known coronary artery disease (P<.0001). Conclusion. This large retrospective study suggests that chest pain during dobutamine stress testing is not a predictor of ischemia when analyzed against reversible perfusion defects on SPECT MPI.     

腺苷负荷心肌灌注显像对近期经皮冠状动脉介入治疗患者的临床价值

目的评估腺苷负荷心肌灌注显像（SMPI）在冠心病患者接受经皮冠状动脉介入治疗（PCI）后的临床价值。方法20例冠心病患者PCI前及后3d内各行1次腺苷SMPI。静息心肌灌注显像（RMPI）于PCI前SMPI的次日进行。心肌显像按17节段5分制进行评分。PCI后1年对患者进行电话随访（随访者不知晓患者的检查结果），在此期间发生心肌梗死或心因性死亡为严重心脏事件（HCE），PCI3个月后再次接受PCI或搭桥手术为非严重心脏事件（SCE）。率的比较行χ^2检验，频数比较行秩和检验。结果PCI前血管供血区域的可逆性节段，PCI后示90．9％（40／44）灌注有改善，不可逆缺损节段亦有41．3％（25／58）显示不同程度的改善。PCI后1年内出现1例HCE，5例SCE，预后与PCI前后受损节段灌注改善情况无关（χ^2=3．17，P〉0．05）。结论PCI后近期腺苷SMPI是评估PCI后心肌灌注的有效方法，其中可逆性缺损改善与否是评估PCI疗效的可靠指征；其预后价值有待进一步研究。     

Prognosis in patients with spontaneous chest pain, a nondiagnostic electrocardiogram, normal cardiac enzymes, and no evidence of severe resting ischemia by quantitative technetium 99m sestamibi tomographic imaging

Background  There are limited data addressing the outcome of patients with normal or near normal myocardial perfusion during chest pain at rest. The purpose of this study was to determine the prognosis of patients with spontaneous chest pain, a normal or nondiagnostic electrocardiogram, no enzymatic evidence of myocardial infarction, and no evidence of severe resting ischemia by quantitative technetium 99m (^99mTc) sestamibi imaging. Methods  In the study, 111 patients who fulfilled the above criteria were injected with ^99mTc sestamibi during resting chest pain and were followed for a median 2.7 years. Of the patients in the study group, 58% had coronary artery disease that was documented by clinical history or coronary angiography. Tomographic ^99mTc perfusion images were interpreted with a quantitative threshold technique initially developed to detect severely hypoperfused myocardium. The images were also interpreted qualitatively to detect patients with milder degrees of hypoperfused myocardium. Results  During follow-up 3 patients had cardiac deaths, 5 had nonfatal myocardial infarctions, and 21 underwent revascularization procedures (13 within 3 months and 8 more than 3 months after the sestamibi study). At 3 years, survival free of cardiac death was 97%, survival free of cardiac death or myocardial infarction was 91%, and survival of cardiac death, myocardial infarction, or late revascularization was 82%. Quantitative analysis of the scans revealed that 100% of patients without fixed defects had 3-year survival free of cardiac death versus 76% of patients who had fixed defects (p<0.001). Mild to moderate resting ischemia by qualitative interpretation of the scans was present in 20% of patients, but this did not predict outcome. Conclusions  Patients with spontaneous chest pain and nonischemic quantitative ^99mTc sestamibi images were at reasonably low risk for hard cardiac events although some patients (18%) required revascularization. Supported in part by the DuPont Merck Pharmaceutical Company, N. Billerica, Mass.     

腺苷与运动负荷心肌灌注显像诊断不典型胸痛心肌缺血的临床价值

目的评价腺苷和运动负荷心肌灌注显像诊断不典型胸痛患者心肌缺血的价值。方法不典型胸痛患者67例行腺苷负荷心肌灌注显像，81例行运动负荷心肌灌注显像，结果分别与冠状动脉（简称冠脉）造影比较，得到显像诊断冠心病心肌缺血的灵敏度、特异性和准确性。结果腺苷负荷心肌灌注显像组67例中，23例冠脉造影有狭窄病变，腺苷负荷心肌灌注显像检出可逆性灌注异常即诊断心肌缺血16例，44例冠脉造影阴性者中，腺苷心肌灌注显像正常41例。腺苷负荷心肌灌注显像诊断冠心病心肌缺血的灵敏度为70％，特异性93％，准确性85％。运动负荷心肌灌注显像组81例中，31例冠脉造影阳性，运动负荷心肌灌注显像检出心肌缺血22例，50例冠脉造影阴性者中，运动负荷心肌灌注显像正常48例。运动负荷心肌灌注显像诊断冠心病心肌缺血的灵敏度为71％，特异性96％，准确性86％。结论腺苷或运动负荷心肌灌注显像出现可逆性灌注异常对诊断不典型胸痛患者冠心病心肌缺血有重要意义。     

Use of coronary calcium scanning for predicting inducible myocardial ischemia: Influence of patients’ clinical presentation

Background  The selection of patients for cardiac stress tests is generally based on assessment of chest pain symptoms, age, gender, and risk factors, but recent data suggest that coronary artery calcium (CAC) measurements can also be used to predict inducible myocardial ischemia. However, the potential influence of clinical factors on the relationship between CAC measurements and inducible ischemia has not yet been investigated. Methods and Results  We prospectively performed CAC scanning in 648 patients undergoing exercise myocardial perfusion single photon emission computed tomography. The frequency of ischemia on myocardial perfusion single photon emission computed tomography was assessed according to CAC magnitude after dividing patients according to chest pain symptom class and Bayesian likelihood of angiographically significant coronary artery disease (ASCAD), Estimates of ASCAD likelihood and CAC scores were poorly correlated. The frequency of inducible myocardial ischemia was very low among patients with a low ASCAD likelihood if CAC scores were less than 400. By contrast, the threshold for increasing ischemia occurred at low CAC scores among patients with a high ASCAD likelihood. When characterized by chest pain classification, asymptomatic and nonanginal chest pain patients had a low frequency of ischemia if CAC scores were less than 400, whereas lower CAC scores did not exclude ischemia among typical angina or atypical angina patients. Conclusions  CAC scores predict myocardial ischemia, with a threshold score of greater than 400 among patients with a low likelihood of ASCAD and those who are asymptomatic or have nonanginal chest pain. These data appear to extend the pool of patients for whom CAC scanning may be useful in ascertaining the need for cardiac stress testing. This study was supported by a grant from the Eisner Foundation, Los Angeles. Calif.     

Preoperative risk stratification using gated myocardial perfusion studies in patients with cancer.

Cancer patients frequently have anemia or an altered coagulation state that may affect their risk stratification for perioperative cardiac events. We performed this study to investigate the incidence of perioperative cardiac events in cancer patients who had abnormal stress myocardial perfusion imaging (MPI) results versus cancer patients with normal MPI results. METHODS: We included 394 consecutive cancer patients with normal (n = 201) or abnormal (n = 193) results on MPI studies performed for preoperative risk stratification. MPI was performed within 6 mo before each patient's scheduled operation. All the patients had surgical procedures requiring general anesthesia, except for 18 who had endoscopic or colonoscopic procedures. We retrospectively reviewed their data for the incidence of major cardiac events intraoperatively and for 1 mo postoperatively. We collected data on their cancer type, risk factors for coronary artery disease, MPI findings, risk of operation, and intraoperative or postoperative major cardiac events, which included death, myocardial infarction (MI), and congestive heart failure (CHF). RESULTS: The patients with abnormal MPI results included 97 with ischemia, 80 with scarring, and 16 with mixed scarring and ischemia. The mean left ventricular ejection fraction and end-diastolic volume were 63.8% +/- 9.8% and 82.0 +/- 53.5 mL in the normal MPI group versus 52.1% +/- 13.1% and 118.1 +/- 53.4 mL in the abnormal-MPI group (P < 0.001). There were 9 major intraoperative or postoperative cardiac events (4.7%) in the patients with abnormal MPI results and none in the patients with normal MPI results (P = 0.001). These major events consisted of 3 deaths, 2 acute MIs, 1 non-Q-wave MI, and 3 cases of CHF. Four of these patients had only scarring on their MPI studies, 3 had ischemia, and 2 had scarring and ischemia. CONCLUSION: Normal MPI results have a high negative predictive value for perioperative cardiac events in cancer patients. Abnormal MPI results, whether demonstrating scarring or ischemia, should prompt appropriate perioperative management in patients with cancer to minimize major cardiac events.     

平板运动试验及心肌灌注显像在飞行人员不典型心肌缺血诊断中的对比研究

目的评价活动平板运动试验对飞行人员不典型心肌缺血的诊断价值，并和心肌灌注显像及冠状动脉造影作对比研究，为其医学鉴定提供参考依据。方法不典型胸痛患者38例，均行活动平板运动试验及心肌灌注显像，结果分别与冠状动脉造影相比较。结果38例冠状动脉造影检查中有13例冠状动脉狭窄病变；运动试验阳性15例，阴性23例；心肌灌注显像检出可逆性心肌缺血16例，阴性22例。运动试验、心肌灌注显像诊断冠心病心肌缺血的灵敏度、特异性、准确性分别为53．8％、68．0％、63．2％和92．3％、84．0％、86．8％。结论活动平板运动试验出现异常ST—T改变，对诊断不典型胸痛患者冠心病心肌缺血有一定的意义，对飞行人员群体的冠心病诊断和排除亦有一定的应用价值。心肌灌注显像在飞行人员体检中的应用价值高于平板运动试验。     

Cost analysis of diagnostic testing for coronary artery disease in women with stable chest pain

BACKGROUND: Seven clinical sites compiled data from 4638 women who were referred directly to coronary angiography (catheterization-first strategy; n = 3375) or who underwent stress myocardial perfusion imaging (MPI) first (n = 1263) followed by coronary angiography if at least one reversible myocardial perfusion abnormality was detected. The study examines the cost minimization potential of these available invasive and noninvasive diagnostic strategies in women with chest pain. METHODS AND RESULTS: Women in both groups were subclassified by the core laboratory as being at low (<0.15), intermediate (0.15 to 0.60), or high (>0.60) pretest likelihood for coronary artery disease (CAD). Among the catheterization-first patients, at least one coronary stenosis >70% was present in 13% of low likelihood patients, 29% of intermediate likelihood patients, and 52% of patients with high CAD likelihood. Perfusion abnormality rates in the MPI-first group were 23% in low likelihood patients, 27% in intermediate likelihood patients, and 34% in high CAD likelihood patients. Of the MPI-first subset, 50%, 55%, and 76%, respectively, underwent catheterization in at least one coronary stenosis >70%. Cardiac death rates ranged from 0.5% to 2.2% in patients with CAD and did not differ from the 2 testing strategies (P = not significant). The composite cost per patient of diagnostic testing plus follow-up medical care over a period of 2.5 +/- 1.5 years (calculated for both strategies from inflation-corrected Medicare charges, adjusted for institutional cost-charge ratios) ranged from $2490 for patients with low likelihood to $3687 for patients with high likelihood with the catheterization-first strategy and from $1587 to $2585 for patients undergoing MPI first (P < .01 between risk subsets and strategies). CONCLUSIONS: In women referred for diagnostic evaluation of stable chest pain, MPI followed by selective coronary angiography in patients with at least 1 perfusion abnormality minimizes the near-term composite cost per patient compared with a direct catheterization-first strategy, regardless of pretest CAD likelihood.