18F-FDG-PET/CT Angiography for the Diagnosis of Infective Endocarditis.

PURPOSE OF REVIEW: This article reviews the current imaging role of 18F-fluordeoxyglucose positron emission computed tomography (18F-FDG-PET/CT) combined with cardiac CT angiography (CTA) in infective endocarditis and discusses the strengths and limitations of this technique. RECENT FINDINGS: The diagnosis of infective endocarditis affecting prosthetic valves and intracardiac devices is challenging because echocardiography and, therefore, the modified Duke criteria have well-recognized limitations in this clinical scenario. The high sensitivity of 18F-FDG-PET/CT for the detection of infection associated with the accurate definition of structural damage by gated cardiac CTA in a combined technique (PET/CTA) has provided a significant increase in diagnostic sensitivity for the detection of IE. PET/CTA has proven to be a useful diagnostic tool in patients with suspected infective endocarditis. The additional information provided by this technique improves diagnostic performance in prosthetic valve endocarditis when it is used in combination with the Duke criteria. The findings obtained in PET/CTA studies have been included as a major criterion in the recently updated diagnostic algorithm in infective endocarditis guidelines.

Implementing a coronary CT angiography protocol based on the body mass index: Radiation dose reduction, image quality, and diagnostic performance.

OBJECTIVES: To evaluate the relation between the coronary calcium score and the posterior choice of kilovoltage according to radiologists' criteria in a standard coronary CT angiography protocol to rule out coronary disease. To quantify the reduction in ionizing radiation after linking kilovoltage to patients' body mass index in a low-dose protocol with iterative model reconstruction. To evaluate the image quality and diagnostic performance of the low-dose protocol. MATERIAL AND METHODS: We compared anthropometric characteristics, calcium score, kilovoltage levels, size-specific dose estimates (SSDE), and the dose-length product (DLP) between a group of 50 patients who were prospectively recruited to undergo coronary CT angiography with a low-dose protocol and a historical group of 50 patients who underwent coronary CT angiography with the standard protocol. We correlated these parameters, the number of coronary segments that could not be evaluated with and without temporal padding, the attenuation, and the signal-to-noise ratio in the ascending aorta in the low-dose protocol with excellent imaging quality according to a semiquantitative scale. To calculate the diagnostic performance per patient, we used 24-month clinical follow-up including all tests as the gold standard. RESULTS: In the standard protocol, the presence of coronary calcium correlated with the selection of high kilovoltage (p = 0.02); this correlation was not found in the low-dose protocol (p = 0.47). Median values of SSDE and DLP were significantly (p < 0.001) lower and less dispersed in the low-dose protocol [9.22 mGy (IQR 7.84-12.1 mGy) vs. 26.5 mGy (IQR 21.3-36.3 mGy) in the standard protocol] and [97 mGy cm (IQR 78-134 mGy cm) vs. 253 mGy cm (IQR 216-404 mGy cm) in the standard protocol], respectively. The overall quality of the images obtained with the low-dose protocol was considered good or excellent in 96% of the studies. The parameters associated with image quality in a multivariable model (C statistic = 0.792) were heart rate (estimated coefficient, -0,12 [95% confidence interval: -0.2, -0.04]; p < 0.01) and the SSDE (estimated coefficient, -0,26 [95% confidence interval: -0.51, -0.01]; p < 0.05). The CAD-RADS modifier for a not fully evaluable or diagnostic study was used on two occasions (4%); the final measures for the diagnosis of coronary disease were sensitivity 100%, specificity 94%, and efficacy 94%. CONCLUSIONS: In the standard protocol, the radiologist selects higher kilovoltage for CT angiography studies for patients whose previous calcium score indicates the presence of coronary calcium. In the low-dose protocol, linking kilovoltage with body mass index enables the dose of radiation to be reduced by 65% while obtaining excellent or good image quality in 96% of studies and excellent diagnostic performance.

Integration of ventricular remodeling, synchrony and filling rate parameters to improve the assessment of left ventricular systolic function.

INTRODUCTION AND OBJECTIVES: The aim of this study is to assess the relationship between structural, remodeling, synchrony, and systolic left ventricular (LV) function parameters using gated-SPECT myocardial-perfusion-images (gSPECT-MPI). In addition, obtaining the cut-off values for end-diastolic LV-shape-index (EDLVsi), end-systolic LV-shape-index (ESLVsi), ECC (eccentricity-index) and PER, and developing a new index to evaluate different patterns of the LV systolic function. METHODS: The study was approved by the Hospital's Ethical-Committee (PR[AG]168.2010), and all patients gave their informed consent. We analyzed prospectively 238 patients (age 63.4 ±â€¯13 years) who underwent stress-rest gSPECT-MPI (control-group, n = 148; patients with previous myocardial infarction [MI], n = 90). RESULTS: In the control group, with regard to remodeling parameters: the end-diastolic-volume-index (EDV) and the ECC were the parameters that influenced the EDLVsi (r2: 0.52, p < 0.001). EDV, PER, men, and the ECC were the parameters (r2: 0.44; p < 0.001) which influenced the ESLVsi. EDLVsi, ESLVsi, LVEF and the stroke-volume were the parameters (r2: 0.62; p < 0.001) which influenced the ECC. With regards to PER: LVEF, heart-rate, bandwidth, and the standard-deviation were the influencing parameters (r2: 0.76; p < 0.001). The cut-off values for EDLVsi, ESLVsi, ECC, and PER were 0.59, 0.42, 0.87, and 3.3, respectively. The PER, the ESLVsi and the bandwidth were the parameters related to patients with previous MI (AUC: 0.89); and they allow the assessment of different patterns of systolic function (PERRS-index: peak-emptying-rate, left ventricular-remodeling and synchrony). CONCLUSIONS: The remodeling, synchrony and the systolic function parameters of the LV should be interpreted together (PERRS-index). In this way, we obtain different patterns of LV systolic function.

Meal size can be decreased in obese subjects through pharmacological acceleration of gastric emptying (The OBERYTH trial).

BACKGROUND: Entry of nutrients into the small intestine activates neuro-hormonal signals that regulate food intake through induction of satiation. OBJECTIVE: To evaluate whether caloric intake can be decreased by pharmacologically accelerating gastric emptying (GE) of nutrients into the small intestine. METHODS: Subjects were tested in 2 days, at baseline (day1) and after randomly receiving, in a double-blind manner, a 1 h infusion of erythromycin (3 mg Kg(-1), to accelerate GE) or placebo (day 2). Ad libitum caloric intake and postprandial gastrointestinal symptoms were evaluated using a validated nutrient drink test, simultaneously measuring gastric emptying [corrected] by scintigraphy. Plasma levels of satiation factors were also measured to evaluate their role in the modification of caloric intake and postprandial symptoms. Acceleration of GE was assessed as the difference in percentage emptied between day 2 and day 1 (DGE). The effects of DGE on caloric intake and symptoms were evaluated using multiple (lineal) regression. RESULTS: Among 30 overweight/obese subjects (24F and 6 M), 15 received erythromycin and 15 placebo. The overall median age was 36 years (IQR: 30-42) and body mass index was 30 Kg m(-2) (IQR: 27-36). Subjects receiving erythromycin on day 2 presented accelerated GE as compared with placebo (P = 0.0002). DGE at 15 min after initiating eating had a significant effect on prospective caloric intake (P = 0.004). From the best-fitted regression model (R (2) = 81%, P < 0.0001), a 10% increase in GE at 15 min induced on an average a 135 ± 43.5 Kcal decrease in caloric intake. Postprandial increase in cholecystokinin (CCK) (P = 0.03) and insulin (P = 0.02) was associated with decreased caloric intake. Acceleration of GE at 60 min after initiating eating increased postprandial symptom scores measured 30 min after the completion of food consumption (P = 0.01). Postprandial increase in CCK (P = 0.002) and PP (P = 0.02) was associated with postprandial symptoms. CONCLUSION: Meal size can be reduced in overweight/obese subjects by pharmacologically accelerating GE. This may be a reasonable target in obesity management.

[Short exercise-rest versus long myocardial perfusion gated SPECT protocols in patients with ischemic cardiomyopathy]. / Protocolo corto esfuerzo reposo frente a protocolo largo en la gated-SPECT de perfusión miocárdica de pacientes con miocardiopatía isquémica.

OBJECTIVE: The purpose of this study was to analyze left systolic ventricular function and myocardial perfusion characteristics between short one day exercise-rest and long two days gated SPECT (Single Photon Emission Computed Tomography) protocols in patients with ischemic cardiomyopathy (ICM). METHODS: A prospective study of 40 patients (59.6±8.9 years, 3 women) with IHD (left ventricular ejection fraction (EF) ≤40%) was performed with myocardial perfusion gated SPECT. From 5 to 10 days after a one-day exercise-rest study (gated SPECT-1), patients were called back for a second rest study (gated SPECT-2) in order to compare EF and differences in perfusion summed rest score (ΔSRS=SRS1-SRS2) and summed difference score (ΔSDS=SDS1-SDS2) between both protocols. RESULTS: Between rest-gated SPECT-1 (short protocol) and rest-gated SPECT-2 (long protocol) EF increased (34% vs 37%, P= 0.008) in 26 patients (65%), and in 11 patients (27.5%) the increase was ≥5%. There were no significant differences in clinical and coronary angiography variables between patients with and without increase of the EF ≥5%. In the multivariate analysis, ΔSRS (95% CI: -1.1 to -29.2) and ΔSDS (0.179-1.236) were predictors for this EF increase between both studies. CONCLUSIONS: Exercise-rest short protocol can underestimate EF in patients with CM. Stunning but also contamination of rest images by previous exercise images in a short protocol could explain these results.

[Image fusion of gated-SPECT and CT angiography in coronary artery disease. Importance of anatomic-functional correlation]. / Fusión de imágenes de gated-SPECT y angiotomografía computarizada en la enfermedad coronaria. Importancia de la correlación anatomicofuncional.

A 77-year old patient was admitted for acute coronary syndrome without ST elevation. His risk was stratified using the myocardial perfusion gated SPECT, mild inferior ischemia being observed. Thus, medical therapy was optimized and the patient was discharged. He continued with exertional dyspnea so a coronary CT angiography was performed. It revealed severe lesions in the proximal RCA. SPECT-CT fusion images correlated the myocardial perfusion defect with a posterior descending artery from the RCA, in a co-dominant coronary area. Subsequently, cardiac catheterism was indicated for his treatment. The current use of image fusion studies is limited to patients in whom it is difficult to attribute a perfusion defect to a specific coronary artery. In our patient, the fusion images helped to distinguish between the RCA and the circumflex artery as the culprit artery of ischemia.

Cost-effectiveness of myocardial perfusion SPECT and stress test according to coronary revascularization therapy, cardiac events and total mortality: Register of 8,496 patients. / Coste-efectividad de la SPECT de perfusión miocárdica y de la prueba de esfuerzo en relación con la revascularización coronaria, eventos cardíacos y mortalidad total. Registro de 8.496 pacientes.

OBJECTIVE: The aim was to analyze the cost-effectiveness ratio (CER) of stress electrocardiogram (ES) and stress myocardial perfusion imaging (SPECT-MPI) according to coronary revascularization (CR) therapy, cardiac events (CE) and total mortality (TM). MATERIAL AND METHODS: A total of 8,496 consecutive patients who underwent SPECT-MPI were followed-up (mean 5.3±3.5years). Cost-effectiveness for coronary bypass (CABG) or percutaneous CR (PCR) (45.6%/54.4%) according to combined electrocardiographic ischemia and scintigraphic ischemia were evaluated. Effectiveness was evaluated as TM, CE, life-year saved observed (LYSO) and CE-LYSO; costs analyses were conducted from the perspective of the health care payer. A sensitivity analysis was performed considering current CABG/PCR ratios (12%/88%). RESULTS: When electrocardiogram and SPECT approaches are combined, the cost-effectiveness values for CABG ranged between 112,589€ (electrocardiographic and scintigraphic ischemia) and 2,814,715€ (without ischemia)/event avoided, 38,664 and 2,221,559€/LYSO; for PCR ranged between 18,824€ (electrocardiographic and scintigraphic ischemia) and 46,377€ (without ischemia)/event avoided, 6,464 and 36,604€/LYSO. To CE: the cost-effectiveness values of the CABG and CPR in presence of electrocardiographic and scintigraphic ischemia were 269,904€/CE-avoided and 24,428€/CE-avoided, respectively; and the €/LYSO of the CABG and PCR were 152,488 and 13,801, respectively. The RCE was maintained for the current proportion of revascularized patients (12%/88%). CONCLUSIONS: Combined ES and SPECT-MPI results, allows differentiation between patient groups, where the PCR and CABG are more cost-effective in different economic frameworks. The major CER in relation to CR, CE and TM occurs in patients with electrocardiographic and scintigraphic ischemia. PCR is more cost-effective than CABG.

[Analysis of the number of patients needed to treat by coronary revascularisation in relation to the presence of myocardial viability in gated SPECT images: a prospective cohort study from a nuclear cardiology unit]. / Análisis del número de pacientes que es necesario tratar mediante revascularización coronaria en relación con la presencia de viabilidad miocárdica en las imágenes de la gated-SPECT: estudio de cohorte prospectivo desde una unidad de cardiología nuclear.

OBJECTIVE: To evaluate the number of patients needed to treat (NNT) to assess the magnitude of benefit of coronary revascularisation (CR) in patients with ischaemic cardiomyopathy (IC) in relation to the presence or absence of myocardial viability in myocardial perfusion gated-SPECT (single photon emission computed tomography) images. METHOD: We studied 198 consecutive patients with IC using rest gated-SPECT with technetium-based agents. The cardiac mortality was analysed in four groups: viable with CR (n = 50), viable with medical treatment (MT) (n = 90), non-viable with CR (n = 18), and non-viable with medical treatment (n = 40). RESULTS: During 2.3 +/- 1.2 years of follow-up, the cardiac mortality rate in patients with scintigraphic viability criteria undergoing revascularisation was 5.9/100 patients/year and 12.9/100 patients/year in those who received medical treatment. In patients without viability who underwent revascularisation, the cardiac mortality rate was 6.2/100 patients/year and in those who received MT it was 1.9/100 patients/year. In patients with myocardial viability the NNT was 4, while in patients without myocardial viability, the NNT was 24. CONCLUSIONS: In patients with scintigraphic viability criteria, the NNT to obtain one survival with CR was 6 times lower with respect to patients without viability, with lower cost and mortality.

[Influence of chronic angina prior to infarction in the diagnosis of viability and left ventricular remodelling in myocardial perfusion gated-SPECT]. / Influencia de la angina crónica previa al infarto en el diagnóstico de viabilidad y remodelado ventricular izquierdo en la gated-SPECT de perfusión miocárdica.

OBJECTIVE: Chronic angina prior to myocardial infarction (CAPMI) is one of the clinical expressions of ischaemic preconditioning. The implications of this physiopathological phenomenon have been of little interest in myocardial perfusion gated SPECT (Single Photon Emission Computed Tomography) studies. The objective was to analyse the influence of CAPMI in the diagnosis of post-infarction myocardial viability and left ventricular remodelling in myocardial perfusion gated SPECT, and between patients with and without diabetes mellitus. METHODS: 131 patients with history of myocardial infarction and depressed systolic function were studied consecutively, analysing the clinical, electrocardiographic and ergometric characteristics and myocardial perfusion gated SPECT in patients with (n = 27) and without (n = 104) CAPMI. RESULTS: Patients with CAPMI were characterised by having a lesser extent of myocardial necrosis, more myocardial viability criteria and less left ventricular remodelling (lower volumes, less apical remodelling and higher EF) on the gated SPECT. Statistical significance for viability, necrosis and ventricular remodelling was not reached between diabetic patients with and without CAPMI. CONCLUSIONS: CAPMI seems to protect patients with ischaemic cardiopathy from having a more extensive infarction at the expense of more residual myocardial viability scintigraphic criteria.

Cardiac 18F-FDG PET/CT procedure for the diagnosis of prosthetic endocarditis and intracardiac devices. / Metodología de la PET/TC con 18F-FDG cardíaca para el diagnóstico de la endocarditis protésica y de dispositivos intracardíacos.

Infective endocarditis (IE) is a serious condition with a poor prognosis, its mortality unchanged significantly despite diagnostic and therapeutic advances in the last 30years. The diagnostic ability of the modified Duke criteria in prosthetic endocarditis and/or devices does not exceed 50%, so new tools are necessary for the diagnosis of this entity in this context. The 18F-FDG PET/CTA combines a highly sensitive technique to detect inflammatory-infectious activity with a technique with high anatomical resolution to assess the structural lesions associated with endocarditis. With a diagnostic sensitivity between 91-97%, this hybrid technique has become a useful diagnostic tool for patients with prosthetic valves or devices and suspicion of IE, becoming a major criterion in the diagnostic algorithm of current guidelines. This excellent diagnostic ability depends directly on the quality of the obtained exploration and the knowledge at the time of interpreting the images. The aim of this review is to describe and standardize the methodology of cardiac 18F-FDG PET/CTA in the diagnosis of endocarditis in prosthetic valves and intracardiac devices, with special emphasis on the particularities of the patient's preparation, the PET and CT acquisition procedures, and the subsequent imaging postprocessing and interpretation.

Simultaneous dipyridamole/maximal subjective exercise with 99mTc-MIBI SPECT: improved diagnostic yield in coronary artery disease.

OBJECTIVES: We attempted to demonstrate that simultaneous dipyridamole administration and maximal subjective exercise in patients who are unable to achieve a good exercise level can improve the diagnostic efficacy of technetium-99m methoxy isobutyl isonitrile (99mTc-MIBI) myocardial single-photon emission computed tomography (SPECT). BACKGROUND: The results of myocardial perfusion scintigraphy are unsatisfactory if the level of exercise achieved by the patient is insufficient. The use of dipyridamole with maximal subjective stress testing has been shown to improve the quality of the thallium-201 myocardial perfusion images, but there are no studies demonstrating that this combination improves the diagnostic accuracy of myocardial perfusion SPECT. METHODS: Two hundred thirty-one consecutive patients, without a previous myocardial infarction, were classified into three groups: group 1, 91 patients with an adequate exercise test; group 2, 68 patients with an inadequate exercise test; group 3, 72 patients with an inadequate exercise test who then received intravenous dipyridamole (0.56 mg/kg body weight over 4 min) simultaneously with exercise. RESULTS: Results for sensitivity (89%) and negative predictive value (83%) in group 3 were significantly better than those in group 2 (71% [p = 0.03] and 56% [p = 0.002], respectively) and not significantly different from those in group 1. The polar maps of 20 patients studied with an without dipyridamole at the same exercise level revealed a significantly greater extent of ischemia in each territory and in a global assessment (19 + 20% vs. 8 + 11%, p < 0.0001) when dipyridamole was administered during physical exercise. CONCLUSIONS: Intravenous dipyridamole administration during exercise testing is advisable in all patients who are unable to achieve an adequate exercise level. This approach permits physicians to avoid missing ergometric information while optimizing myocardial SPECT results.

[Quantitative evaluation of 123I-FP-CIT SPECT: validation of a semiautomated method]. / Evaluación cuantitativa del SPET con 123I-FP-CIT: validación de un método semiautomático.

OBJECTIVE: To assess the utility of a quantification of the 123I-FP-CIT uptake by the definition of some reference values, normal range values and interobserver variation. PATIENTS AND METHOD: Fifty patients with a 123I-FP-CIT SPECT: 25 patients had a pathological SPECT with the diagnosis of Parkinson's disease and the remaining had a qualitative normal SPET, with the diagnosis of 14 drug-induced Parkinsonism and 11 with psychogenic Parkinsonism. In the transversal slices, the best central slice that showed the nuclei of the base best was selected and standard ROIs (Region Of Interest) were applied. Specific (caudate and putamen) versus non specific (occipital) and laterality ratios were calculated. A normal statistical analysis for independent quantitative samples was used (mean, standard deviation and range) as well as variation coefficient and correlation coefficient of two observers and the 10th and 90th percentile. RESULTS: The variation coefficient interobserver was 3.24-5.61 and the correlation coefficient was 0.89-0.99. Cut-off values between both populations were established at 2.10 in the right putamen and at 2.05 in the left. Cut-off values definition in caudate were not assessable due to overlapping of ratios of both populations. CONCLUSIONS: This quantification method is highly reproducible. It makes it possible to obtain reference values and to define normal range.

[Acute stent thrombosis and reverse transient left ventricular dilatation after performing a single-photon emission computed tomography myocardial perfusion]. / Trombosis aguda de stent y dilatación transitoria ventricular izquierda inversa tras la realización de una tomografía computarizada de emisión monofotónica de esfuerzo.

A 63-year-old male patient with a history of stent implantation in the left anterior descending three months before. Due to the presentation of vegetative symptoms, he was referred for gated-SPECT myocardial perfusion. During acquisition of the resting images he presented chest pain and ST segment elevation, so that urgent cardiac catheterization was performed, showing stent thrombosis. Rest perfusion imaging showed a defect in anterior and apical perfusion, more severe and extensive than in the stress images, with striking left ventricular dilatation and a fall in the ejection fraction related to the acute ischemia phenomenon. Intense exercise is associated with a transient activation of the coagulation system and hemodynamic changes that might induce thrombosis, especially in recently implanted coronary stents that probably still have not become completely endothelialized.

[Obtaining a formula that improves maximum oxygen consumption estimation in cycle ergometer exercise tests]. / Obtención de una fórmula que mejora la estimación del consumo máximo de oxígeno en las pruebas de esfuerzo con bicicleta ergométrica.

OBJECTIVES: To evaluate if the estimation of the maximal oxygen consumption (MO2C) in METs (metabolic equivalents) by means of the table proposed in the guidelines of the Spanish Society of Cardiology is a sufficiently reliable method when applied to the bicycle exercise test. MATERIAL AND METHODS: The MO2C in METs was obtained by gas-exchange analysis on bicycle ergometer tests in 97 healthy subjects (group i). It was compared with the estimate of METs using the table in which only watts and patient's weight were included. A better-adjusted formula was validated in 289 subjects with normal exercise myocardial perfusion gated-SPECT (group ii) using the introduction of clinical and ergometric variables. RESULTS: In group i individuals a good correlation between METs estimated with the table and those obtained through gas-exchange analysis (CCI: 0.93) was observed. However, the best adjusted formula to estimate METs in group ii subjects included watts, body mass index (BMI), age and gender (METS=11.820-0.054×age-0.189×BMI+1.031×gender+0.020×watts) (women: 0, men: 1). This formula allowed the reclassification of 46.9% of group ii subjects into the category <5METs versus the estimation by table. CONCLUSIONS: Estimating the METs with the conventional table is reliable. However, the best adjustment in subjects with normal bicycle exercise SPECT was obtained when, in addition to watts and BMI, age and gender were also considered.

[SPECT, coronary angio-CT, invasive coronary angiography and fusion images in stable coronary disease]. / SPECT, angio-TC coronaria, coronariografía invasiva e imágenes de fusión en la cardiopatía isquémica estable.

OBJECTIVES: To evaluate the usefulness of the information obtained with SPECT, coronary angio-CT and fusion images, in patients with stable ischemic disease who need invasive coronary angiography (IA). MATERIAL AND METHODS: Forty-six patients (65.98±8.3 years) with coronary disease were prospectively included. The fusion images generated after undergoing IA were used to evaluate the performance of these techniques in the diagnosis of multi-vessel coronary disease, the detection of the culprit vessel and the therapeutic management of these patients. RESULTS: In the IA, 29 of the 46 patients (63%) had multi-vessel disease. SPECT could detect it in 48.2% and coronary angio-CT could detect it in 89.6%. Concordance between coronary angio-CT and IA in the diagnosis of the culprit vessel was 77% (kappa 0.6), and between SPECT and IA it was 73% (kappa 0.56). Although fusion images could have been obtained prior to IA, they would not have changed the therapeutic approach derived from SPECT and IA. CONCLUSIONS: Coronary angio-CT has a high ability for the diagnosis of multi-vessel disease and the culprit lesion, and SPECT is a good functional complement of the IA in the detection of the most ischemic territory. However, the performance of fusion images in patients with stable ischemic disease, who have undergone a SPECT as the first non-invasive study and need IA, does not seem indicated because they would not have changed the therapeutic management derived from SPECT and IA information.

Frequency and clinical significance of myocardial ischemia detected early after coronary stent implantation.

UNLABELLED: A high number (30%-50%) of reversible defects have been detected early after coronary balloon angioplasty. Inadequate luminal enlargement despite a good angiographic appearance has been suggested as a possible mechanism of these perfusion abnormalities, and some reports have shown better coronary flow reserve after coronary stent implantation than after balloon dilatation. The primary objective of this study was to evaluate the frequency of early ischemic defects detected by maximal exercise (plus dipyridamole) with (99m)Tc-tetrofosmin SPECT after successful coronary angioplasty with stent implantation. A secondary objective was to determine the prognostic value of these early ischemic defects. METHODS: Thirty patients without previous myocardial infarction who successfully underwent 1-vessel coronary angioplasty with stent implantation were studied. Maximal-exercise (99m)Tc-tetrofosmin myocardial SPECT, with simultaneous dipyridamole if exercise was suboptimal, was performed at 6 +/- 1 d (mean +/- SD) after percutaneous transluminal coronary angioplasty. At 8 +/- 3 mo, all patients were followed up clinically, and 77% of them underwent follow-up angiography. RESULTS: The percentage of stenosis decreased from 68.5% +/- 12.6% of luminal diameter to 9.3% +/- 8.8% after stent implantation, and minimal luminal diameter increased from 0.89 +/- 0.36 mm to 2.85 +/- 0.45 mm. Mild-to-moderate reversible myocardial defects in the territory of the dilated artery were detected in 5 patients (17%), with no angiographic or procedural differences occurring between them and patients without ischemic defects. At follow-up, the target lesion revascularization rates depending on the presence or absence of early ischemic defects were 40% and 8%, respectively (P = 0.18). Angiographic restenosis occurred in 3 of 4 patients who had early ischemic defects and underwent follow-up angiography and in 3 of 19 patients who had no early ischemic defects and underwent follow-up angiography (restenosis rate, 75% and 16%, respectively; P < 0.05). CONCLUSION: Coronary angioplasty with stent implantation is associated with a 17% rate of ischemic defects early after the procedure. Patients with early myocardial perfusion defects after coronary stent implantation had a high rate of restenosis.

Relationship between the location of the most severe myocardial perfusion defects, the most severe coronary artery stenosis, and the site of subsequent myocardial infarction.

UNLABELLED: This study evaluated the relationship between the location of the most severe myocardial perfusion defects, the most severe coronary artery stenosis, and the site of subsequent acute myocardial infarction (AMI). METHODS: Of 3,180 patients who were admitted with a diagnosis of AMI, we identified 44 patients who had undergone previous myocardial perfusion SPECT. Thirty-one of them also had previous coronary angiography. The relationship between the location of the myocardial perfusion defects, the coronary artery stenosis, and the site of subsequent AMI was studied in these patients. RESULTS: The concordance between the location of the most severe reversible defects detected by SPECT and the site of subsequent AMI was 71% (kappa = 0.499). The concordance between the most severe stenosis detected by coronary angiography and the site of subsequent AMI was 64% (kappa = 0.451). However, kappa values for SPECT and coronary angiography were good when the interval between these investigations and subsequent AMI was <3 mo (0.724 and 0.661, respectively), for moderate to severe perfusion defects (0.719), and for 90%-99% coronary stenosis (0.626). CONCLUSION: The culprit lesion is not always the one that is manifested by the most severe reversible perfusion defect or the most critical coronary artery stenosis. Myocardial SPECT and coronary angiography can predict the location of a future AMI in 71% and 64% of patients, respectively. The percentage is higher when the interval between investigations and subsequent AMI is <3 mo, for moderate to severe perfusion defects, and for 90%-99% coronary stenosis.

Diagnostic accuracy of technetium-99m-MIBI myocardial SPECT in women and men.

UNLABELLED: Noninvasive diagnosis of coronary artery disease in women has some limitations due to a higher percentage of false-positive results. In addition, a lower prevalence of disease can be observed in this population. In this study, we evaluated the diagnostic accuracy of 99mTc-methoxy-isobutyl-isonitrile (MIBI) SPECT in women and men, in a group of patients with proven coronary artery disease by coronary angiography (select minority) and in all patients where a noninvasive test (silent majority) was performed. METHODS: Seven hundred and two consecutive patients without previous myocardial infarction were studied with 99mTc-MIBI myocardial SPECT. One hundred sixty-three patients had coronary angiography (select minority) and 539 did not (silent majority). All patients underwent exercise stress testing, and simultaneous dipyridamole was administered in 32% of patients who did not achieve maximum predicted heart rates. Diagnostic accuracy of the test was calculated for the select minority. Then, sensitivity and specificity of the silent majority were recalculated according to the Diamond criteria. RESULTS: Prevalence of coronary artery disease (32% versus 80%, p = 0.0001) and peak O2 consumption achieved in exercise tests (watts, exercise duration) were lower in women. The probability of positive results of 99mTc-MIBI SPECT also was lower in women (34% versus 65%). The sensitivity of 99mTc-MIBI SPECT in women of the select minority was lower (85% versus 93%, p = 0.01), whereas there was no significant difference for specificity (91% versus 89%). After correcting the results for the silent majority, there were no significant differences in sensitivity (87% versus 88%) and specificity (91% versus 96%) between women and men. These results were not different for patients who achieved maximum predicted heart rates during stress testing (without dipyridamole administration). CONCLUSION: The sensitivity of 99mTc-MIBI myocardial SPECT in women was lower than in men when only the select minority was considered. When the silent majority was considered (correction of selection bias) sensitivity and specificity results did not differ significantly between the sexes.