Alessia Gimelli

Value of rest thallium-201/technetium-99m sestamibi scans and dobutamine echocardiography for detecting myocardial viability

The relation between radioisotopic and echocardiographic markers of myocardial viability and postrevascularization recovery of function is still to be defined. To this purpose, 14 patients (11 men, 3 women, aged 35 to 64 years, mean 54 +/- 7) with ventricular dysfunction were studied by a multiparametric approach. Each patient underwent, on separate days, rest thallium-201 and technetium-99m sestamibi scintigraphy, dobutamine echocardiography and coronary angiography. Coronary angiography was analyzed by a quantitative approach. Thallium uptake at rest was quantified from planar early (10-minute) and delayed (16-hour) thallium-201 images and expressed as a percentage of maximal activity in each projection using a 13-segment model. Sestamibi uptake was expressed in the same way. Dobutamine (up to 10 micrograms/kg/min) echocardiography was analyzed using a score index ranging from 1 (normokinesia) to 4 (dyskinesia) and a similar segmental model. Before revascularization 50 segments were grouped as normal (coronary stenosis < 50% and normal function, group 1); of the remaining 132 segments with > 50% coronary stenosis, 57 had normal wall motion (group 2) and 75 showed regional dyssynergies (group 3). Early and delayed thallium-201 regional percent activities did not differ in group 1 and in group 2 but were significantly less in group 3 segments. Sestamibi percent activity was more in group 1 and significantly reduced both in group 2 and 3 segments. Segments with improved wall motion after dobutamine had more early, delayed thallium-201 and sestamibi percent activities than unresponsive segments. Postrevascularization echocardiography was performed in all patients. Delayed thallium-201 scans and dobutamine echocardiography showed good sensitivity and specificity in detecting viable myocardium. (ABSTRACT TRUNCATED AT 250 WORDS)

Detection of significant coronary artery disease by noninvasive anatomical and functional imaging.

Background—The choice of imaging techniques in patients with suspected coronary artery disease (CAD) varies between countries, regions, and hospitals. This prospective, multicenter, comparative effectiveness study was designed to assess the relative accuracy of commonly used imaging techniques for identifying patients with significant CAD. Methods and Results—A total of 475 patients with stable chest pain and intermediate likelihood of CAD underwent coronary computed tomographic angiography and stress myocardial perfusion imaging by single photon emission computed tomography or positron emission tomography, and ventricular wall motion imaging by stress echocardiography or cardiac magnetic resonance. If ≥1 test was abnormal, patients underwent invasive coronary angiography. Significant CAD was defined by invasive coronary angiography as >50% stenosis of the left main stem, >70% stenosis in a major coronary vessel, or 30% to 70% stenosis with fractional flow reserve ⩽0.8. Significant CAD was present in 29% of patients. In a patient-based analysis, coronary computed tomographic angiography had the highest diagnostic accuracy, the area under the receiver operating characteristics curve being 0.91 (95% confidence interval, 0.88–0.94), sensitivity being 91%, and specificity being 92%. Myocardial perfusion imaging had good diagnostic accuracy (area under the curve, 0.74; confidence interval, 0.69–0.78), sensitivity 74%, and specificity 73%. Wall motion imaging had similar accuracy (area under the curve, 0.70; confidence interval, 0.65–0.75) but lower sensitivity (49%, P<0.001) and higher specificity (92%, P<0.001). The diagnostic accuracy of myocardial perfusion imaging and wall motion imaging were lower than that of coronary computed tomographic angiography (P<0.001). Conclusions—In a multicenter European population of patients with stable chest pain and low prevalence of CAD, coronary computed tomographic angiography is more accurate than noninvasive functional testing for detecting significant CAD defined invasively. Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifier: NCT00979199.

Homogeneously Reduced Versus Regionally Impaired Myocardial Blood Flow in Hypertensive Patients: Two Different Patterns of Myocardial Perfusion Associated With Degree of Hypertrophy

OBJECTIVES The aim of this study was to quantitatively measure regional and global myocardial blood flow and coronary reserve in hypertensive patients without coronary artery disease and to assess the correlation with left ventricular mass. BACKGROUND The effect of left ventricular hypertrophy on regional vasodilating coronary capability in arterial hypertension is controversial, and no quantitative method has been applied to assess a possible correlation. METHODS Positron emission tomography was performed in 50 untreated hypertensive patients and 13 normotensive subjects. Blood flow at baseline and after dipyridamole was globally and regionally measured by using nitrogen-13 ammonia; coronary reserve and resistance were calculated. Left ventricular mass was assessed by two-dimensional echocardiography. RESULTS In hypertensive patients, flow at baseline was similar to that of normotensive subjects (p = 0.21), but values were reduced after pharmacologic vasodilation (p < 0.05). This impairment of maximal coronary flow was not correlated with left ventricular mass (p = 0.13). Among hypertensive patients, we identified a group with a homogeneous distribution of perfusion and a group with a heterogeneous flow pattern. Flow was globally reduced in the former group, but it was abnormal only at the site of perfusion defects in the latter. Patients with regional defects showed the highest likelihood of having an increased left ventricular mass. CONCLUSIONS In arterial hypertension, left ventricular mass is not correlated with global myocardial blood flow. Nevertheless, patients with ventricular hypertrophy are likely to show a heterogeneous flow pattern with regional defects and almost normal blood flow in nonaffected regions. In hypertensive patients with a homogeneous perfusion pattern during stress, myocardial blood flow frequently shows a diffuse reduction.

EACVI/EHRA Expert Consensus Document on the role of multi-modality imaging for the evaluation of patients with atrial fibrillation

Atrial fibrillation (AF) is the commonest cardiac rhythm disorder. Evaluation of patients with AF requires an electrocardiogram, but imaging techniques should be considered for defining management and driving treatment. The present document is an expert consensus from the European Association of Cardiovascular Imaging (EACVI) and the European Heart Rhythm Association. The clinical value of echocardiography, cardiac magnetic resonance (CMR), computed tomography (CT), and nuclear imaging in AF patients are challenged. Left atrial (LA) volume and strain in echocardiography as well as assessment of LA fibrosis in CMR are discussed. The value of CT, especially in planning interventions, is highlighted. Fourteen consensus statements have been reached. These may serve as a guide for both imagers and electrophysiologists for best selecting the imaging technique and for best interpreting its results in AF patients.

Stress/Rest Myocardial Perfusion Abnormalities by Gated SPECT: Still the Best Predictor of Cardiac Events in Stable Ischemic Heart Disease

The prognostic power of myocardial perfusion imaging in patients with ischemic heart disease (IHD) has been demonstrated since planar imaging. We aimed to investigate whether gated SPECT retains this value in current cardiology if compared with a complete diagnostic work-up and with more recent prognostic indicators. Methods: We selected from our database a cohort of 676 consecutive inpatients who underwent a complete diagnostic work-up that included gated SPECT and coronary arteriography for known or suspected IHD. Patients with acute myocardial infarction (MI), previous coronary artery bypass surgery, or overt hyperthyroidism and patients who were undergoing dialysis treatment were excluded. During follow-up (median, 37 mo), 24 patients died from cardiac causes and 19 experienced a nonfatal MI. Results: The following were determined to be independent predictors of event-free survival (cardiac death and nonfatal MI) in the different phases of diagnostic work-up using Cox proportional hazards regression analysis: among clinical variables, a previous MI; among laboratory examinations, serum creatinine and low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol levels; among electrocardiographic and echocardiographic variables, left ventricular ejection fraction; and among SPECT variables, summed rest score (SRS) and summed difference score (SDS). In addition, a score of coronary stenoses at angiography was an independent predictor. When the above predictors were tested together, SRS (P < 0.0001), SDS (P = 0.0108), and serum creatinine (P = 0.0186) and LDL and HDL cholesterol levels (P = 0.0222) were the final independent predictors of event-free survival. When gated SPECT was added to the clinical, laboratory, electrocardiographic, and echocardiographic variables, the prognostic stratification significantly improved (P < 0.05); when coronary arteriography was added to gated SPECT, prognostic stratification did not further improve (P > 0.25). If the information provided by gated SPECT was made available after clinical, laboratory, electrocardiographic, echocardiographic, and angiographic variables, the prognostic stratification still improved significantly (P < 0.05). In 492 of these patients with ascertained IHD, SRS and SDS were the final independent predictors of survival. Medical treatment and coronary revascularization did not affect the prognostic information of gated SPECT. Conclusion: Myocardial perfusion abnormalities at rest and after stress are still the best predictors of cardiac event–free survival in patients with known or suspected IHD, even when compared with an extensive diagnostic work-up.

Comparison Between Ultrafast and Standard Single-Photon Emission CT in Patients With Coronary Artery Disease: A Pilot Study

Background—A novel technology has been developed for ultrafast (UF) single-photon emission CT (SPECT) myocardial perfusion imaging by using a pinhole collimation design and multiple cadmium zinc telluride crystal arrays. The purpose of this study was to compare myocardial perfusion imaging obtained by UF-SPECT with standard (S) SPECT in patients with known or suspected coronary artery disease. Methods and Results—A total of 34 patients underwent single-day 99mTc-tetrofosmin stress/rest myocardial perfusion imaging. UF-SPECT was performed 10 minutes before S-SPECT. Images were qualitatively analyzed, and the summed stress score and summed rest score were calculated. The segmental tracer uptake value (percentage of maximum myocardial uptake) also was quantified for both UF- and S-SPECT. When only 29 of 34 patients with significant coronary lesions were analyzed, the summed stress score was 10.1±4.4 versus 6.4±2.9, respectively, for UF- and S-SPECT (P=0.002). Qualitative and quantitative per-patient analysis showed similar results in detection of coronary artery disease for UF- and S-SPECT. In contrast, per-vessel analysis demonstrated higher regional sensitivity of UF- versus S-SPECT. UF-SPECT showed higher sensitivity in detecting multivessel disease (P=0.003) versus S-SPECT. Conclusions—This pilot study confirms that UF-SPECT provides high-quality fast myocardial perfusion imaging and suggests that it may allow a more-accurate evaluation of both extent and severity of myocardial ischemia in patients with coronary artery disease.

Comparison Between Ultrafast and Standard SPECT in Patients with Coronary Artery Disease: A Pilot Study

Background—A novel technology has been developed for ultrafast (UF) single-photon emission CT (SPECT) myocardial perfusion imaging by using a pinhole collimation design and multiple cadmium zinc telluride crystal arrays. The purpose of this study was to compare myocardial perfusion imaging obtained by UF-SPECT with standard (S) SPECT in patients with known or suspected coronary artery disease. Methods and Results—A total of 34 patients underwent single-day 99mTc-tetrofosmin stress/rest myocardial perfusion imaging. UF-SPECT was performed 10 minutes before S-SPECT. Images were qualitatively analyzed, and the summed stress score and summed rest score were calculated. The segmental tracer uptake value (percentage of maximum myocardial uptake) also was quantified for both UF- and S-SPECT. When only 29 of 34 patients with significant coronary lesions were analyzed, the summed stress score was 10.1±4.4 versus 6.4±2.9, respectively, for UF- and S-SPECT (P=0.002). Qualitative and quantitative per-patient analysis showed similar results in detection of coronary artery disease for UF- and S-SPECT. In contrast, per-vessel analysis demonstrated higher regional sensitivity of UF- versus S-SPECT. UF-SPECT showed higher sensitivity in detecting multivessel disease (P=0.003) versus S-SPECT. Conclusions—This pilot study confirms that UF-SPECT provides high-quality fast myocardial perfusion imaging and suggests that it may allow a more-accurate evaluation of both extent and severity of myocardial ischemia in patients with coronary artery disease.

Comparison of combination of dipyridamole and dobutamine during echocardiography with thallium scintigraphy to improve viability detection

Abstract The aim of this study was to investigate the relation between radioisotopic and echocardiographic markers of myocardial viability and their correlation with functional recovery after coronary revascularization. Myocardial viability can be detected by techniques exploring various aspects of cell physiology: thallium-201 scintigraphy and dobutamine and dipyridamole echocardiography focus on cell membrane integrity, β-1 and adrenoceptor, and A2-adenosine receptor-mediated inotropic response, respectively. Fifty-seven patients (mean age 60 ± 8 years) with previous myocardial infarction (>3 months), angiographically assessed coronary artery disease, and resting regional dysfunction underwent rest-redistribution 201-thallium scintigraphy and low-dose pharmacologic stress echo with dobutamine (up to 10 μg/kg/min), very low dose regimen of dipyridamole (0.28 mg/kg over 4 minutes), and combined dipyridamole-dobutamine. Criteria for viability in a 13-segment model for both techniques were percent peak activity in redistribution images >55% for thallium-201 and a decrease in wall motion score >1 grade (1 [normal] to 4 [dyskinetic]) for stress echo. Thirty patients underwent coronary revascularization (bypass surgery in 8, angioplasty in 22) and were followed up at 4 weeks from intervention with a resting echocardiogram. The rate of agreement between thallium-201 and stress echo was 63% for dipyridamole, 66% for dobutamine, and 74% for combined dipyridamole-dobutamine (p

Regional concordance and discordance between rest thallium 201 and sestamibi imaging for assessing tissue viability: Comparison with postrevascularization functional recovery+

BackgroundWhether the combined analysis of rest 201Tl and sestamibi uptake provides additional information regarding myocardial viability in patients with coronary artery disease is still to be investigated.Methods and ResultsTo this aim we studied 22 patients with previous myocardial infarction and regional ventricular dysfunction by quantitative rest sestamibi and 201Tl scintigraphy. All patients underwent revascularization, and echocardiography was repeated 11±2 weeks later. Concordant results were obtained in 80 of 105 dyssynergic segments. Fifty-one segments showed normal and 29 abnormal activity. Follow-up echocardiography showed increased wall motion contractility in 76% of segments with maintained 201Tl and sestamibi uptake and in only 17% of segments characterized by subthreshold activities. Twenty-five segments, or 24%, showed sestamibi/201Tl mismatch. Eleven of 12 segments with normal sestamibi/abnormal 201Tl activity did not improve after revascularization, whereas 11 of 13 segments with abnormal sestamibi but normal 201Tl showed postoperative improvement of regional wall motion.ConclusionsIn patients with previous myocardial infarction, sestamibi and 201Tl showed concordant results in most segments. However, in segments with mismatch a maintained sestamibi uptake was a poor indicator of tissue viability, whereas significant 201Tl uptake reflected tissue viability in most segments.

Multicentre multi-device hybrid imaging study of coronary artery disease: results from the EValuation of INtegrated Cardiac Imaging for the Detection and Characterization of Ischaemic Heart Disease (EVINCI) hybrid imaging population

AIMS Hybrid imaging provides a non-invasive assessment of coronary anatomy and myocardial perfusion. We sought to evaluate the added clinical value of hybrid imaging in a multi-centre multi-vendor setting. METHODS AND RESULTS Fourteen centres enrolled 252 patients with stable angina and intermediate (20-90%) pre-test likelihood of coronary artery disease (CAD) who underwent myocardial perfusion scintigraphy (MPS), CT coronary angiography (CTCA), and quantitative coronary angiography (QCA) with fractional flow reserve (FFR). Hybrid MPS/CTCA images were obtained by 3D image fusion. Blinded core-lab analyses were performed for CTCA, MPS, QCA and hybrid datasets. Hemodynamically significant CAD was ruled-in non-invasively in the presence of a matched finding (myocardial perfusion defect co-localized with stenosed coronary artery) and ruled-out with normal findings (both CTCA and MPS normal). Overall prevalence of significant CAD on QCA (>70% stenosis or 30-70% with FFR≤0.80) was 37%. Of 1004 pathological myocardial segments on MPS, 246 (25%) were reclassified from their standard coronary distribution to another territory by hybrid imaging. In this respect, in 45/252 (18%) patients, hybrid imaging reassigned an entire perfusion defect to another coronary territory, changing the final diagnosis in 42% of the cases. Hybrid imaging allowed non-invasive CAD rule-out in 41%, and rule-in in 24% of patients, with a negative and positive predictive value of 88% and 87%, respectively. CONCLUSION In patients at intermediate risk of CAD, hybrid imaging allows non-invasive co-localization of myocardial perfusion defects and subtending coronary arteries, impacting clinical decision-making in almost one every five subjects.