Segmental Myocardial Perfusion Research Articles

Changes in myocardial perfusion according to left ventricular pacing site in cardiac resynchronization therapy

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): 1. The Danish Heart Foundation 2. The Health Research Fund of the Central Denmark Region Background/Introduction Changes in left ventricular (LV) myocardial perfusion according to LV pacing site during cardiac resynchronization therapy (CRT) has only been sparsely described. Purpose To assess changes in LV global and regional myocardial perfusion according to LV pacing site after six months CRT. Methods Data from patients enrolled in the randomized controlled trial "Electrically vs. Imaging-guided Left Ventricular Lead Placement in Cardiac Resynchronization Therapy" was evaluated. Global and segmental absolute myocardial perfusion in ml/g/min was assessed by 82Rb-PET the day before CRT implantation and at six-months follow-up (6MFU). The exact LV pacing site was determined by post-implant cardiac CT. Perfusion and pacing site were evaluated using the standard 17’-segment LV model. Echocardiographic assessment of LV ejection fraction (EF) was performed the day before CRT implantation and at 6MFU. Results 93 patients (age 71±9 years; ischemic heart disease 48%; female 25%; median QRS 166±20 ms; mean LVEF 30±7%; NYHA class I/II/III/IV (%) 0/63/33/3) were included. Distribution of LV pacing sites is shown in Figure 1. No change in LV global perfusion was observed from baseline to 6MFU (0.79 to 0.81 ml/g/min, P=0.41; respectively). LV EF increased by 9±10%. Baseline global perfusion was higher in the 39 patients in whom LV EF had increased ≥10% at 6MFU (0.86 vs. 0.74 ml/g/min, P=0.02; respectively). However, no difference in perfusion-change was observed between patients with ≥10% increase in LV EF at 6MFU and patients with <10% increase (0.01 vs. 0.02 ml/g/min, P=0.76; respectively). Baseline perfusion was higher in the segments chosen for LV-pacing than in the non-paced segments (0.96 vs. 0.78 ml/g/min, P=0.00; respectively). Perfusion in the paced segments dropped to 0.86 ml/g/min (P=0.00) at 6MFU. Perfusion in the neighbouring segments also dropped during six months (from 0.91 to 0.86 ml/g/min, P=0.03), while perfusion in the non-paced and non-neighbouring segments increased (from 0.75 to 0.80 ml/g/min, P=0.01). Conclusion Despite a mean increase in LV EF of 9%, global myocardial perfusion remained unchanged. CRT resulted in a homogenous distribution of myocardial perfusion with a decreased perfusion in segments concordant and adjacent to LV pacing site and a corresponding increased perfusion in remote segments.

Incremental value of myocardial wall motion and thickening to perfusion alone by gated SPECT myocardial perfusion imaging for viability assessment in patients with ischemic heart failure

PurposeThe objective of this study was to assess the incremental value of myocardial wall motion and thickening compared with perfusion alone obtained from gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) in diagnosing myocardial viability in patients with ischemic heart failure. MethodsEighty-three consecutive patients with ischemic heart failure who underwent both 99mTc-MIBI gated SPECT MPI and 18F-FDG positron emission tomography (PET) myocardial metabolic imaging were retrospectively enrolled. SPECT/PET myocardial viability was defined as the reference standard. Segmental myocardial perfusion, wall motion, and thickening were measured by an automated algorithm from gated SPECT MPI. Univariate and stepwise multivariate analysis were conducted to establish an optimal multivariate model for predicting hibernating myocardium and scar. ResultsAmong the 1411 segments evaluated, 774 segments had normal perfusion and 637 segments had decreased perfusion. The latter were classified by 18F-FDG PET into 338 hibernating segments and 299 scarred segments. The multivariate regression analysis showed that the model that combined myocardial perfusion uptake with wall motion and thickening scores had the optimal predictive efficiency to distinguish hibernating myocardium from scar in the segments with decreased perfusion. The model had the largest C-statistic (0.753 vs 0.666, P < 0.0001), and the global chi-square was increased from 53.281 to 111.234 when compared with perfusion alone (P < 0.001). ConclusionsAssessment of myocardial wall motion and thickening in addition to conventional perfusion uptake in the segments with decreased perfusion enables better differentiation of hibernating myocardium from scar in patients with ischemic heart failure. Considering wide availability and high cost-effectiveness, regional myocardial function integrated with perfusion on gated SPECT MPI has great promise to become a clinical tool in the assessment of myocardial viability.

Abstract 9397: Sonothrombolysis Improves Cardiac Segmental Contractility, Myocardial Perfusion and Baroreflex Gain in Patients With ST-segment Elevation Myocardial Infarction (stemi) in Long-Term Follow-Up

Sonothrombolysis (Sono) has improved microvascular obstruction, global contractility and infarct area after STEMI. Objective: To evaluate the long-term effect of Sono and its physiologic mechanisms in a subgroup of 51 STEMI patients (percutaneous coronary intervention-PCI (N=24) and PCI+Sono (N=27)) from previous randomized study. All patient were treated with PCI and those also treated with Sono received frequent image-guided diagnostic high mechanic index impulses applied to the myocardial contrast-enhanced areas (microbubbles) in the apical views (1.8 MHz; 1.1 to 1.3 MI; &lt;5-μ pulse duration). Evaluations were at pre-treatment, 1 month (ultrasound-US with contrast agent) and at averaged 34±17 months after STEMI (US with contrast agent; cardiac and peripheral sympathetic activity by means of 123 I-MIBG cardiac scintigraphy and microneurography; baroreflex gain of heart rate (HR) control by means of transfer function analysis). (For significance: P level ≤ 0.05). US values are on table. Adding, PCI+Sono showed lower left ventricular end-diastolic volume (LVEDV) remodelling (22±36 vs. 44±42%, P&lt;0.05). Cardiac scintigraphy showed similar late Heart/Mediastinum ratio and similar washout rate between groups. Muscle sympathetic nervous activity was also similar in both groups. PCI+Sono showed higher baroreflex gain of HR control (8±3 vs. 6±2 ms/mmHg, P=0.05), indicating an improved baroreflex sensitivity. In addition, perfusion score index correlated positively with wall motion score index (r=0.97, P&lt;0.001) and washout rate (r=0.30, P=0.04). LV ejection fraction correlated negatively with wall motion score index (r=-0.53), perfusion score index (r=-0.48) and LVEDV (r=-0.29) (P&lt;0.05). In conclusion, Sono added to PCI improved contractility and myocardial perfusion in STEMI. Despite high level of sympathetic activity, baroreflex gain of HR was ameliorated in PCI+Sono patients, probably due to better myocardial perfusion and lower LV remodelling.

Assessment of segmental myocardial blood flow and myocardial perfusion reserve by adenosine-stress myocardial arterial spin labeling perfusion imaging.

To determine the feasibility of measuring increases in myocardial blood flow (MBF) and myocardial perfusion reserve (MPR) on a per-segment basis using arterial spin labeled (ASL) magnetic resonance imaging (MRI) with adenosine vasodilator stress in normal human myocardium. Myocardial ASL scans at rest and during adenosine infusion were incorporated into a routine 3T MR adenosine-induced vasodilator stress protocol and were performed in 10 healthy human volunteers. Myocardial ASL was performed using single-gated flow-sensitive alternating inversion recovery (FAIR) tagging and balanced steady-state free precession (bSSFP) imaging at 3T. A T2 -prep blood oxygen level-dependent (BOLD) SSFP sequence was used to concurrently assess segmental myocardial oxygenation with BOLD signal intensity (SI) percent change in the same subjects. There was a statistically significant difference between MBF measured by ASL at rest (1.75 ± 0.86 ml/g/min) compared to adenosine stress (4.58 ± 2.14 ml/g/min) for all wall segments (P < 0.0001), yielding a per-segment MPR of 3.02 ± 1.51. When wall segments were divided into specific segmental myocardial perfusion territories (ie, anteroseptal, anterior, anterolateral, inferolateral, inferior, and inferoseptal), the differences between rest and stress regional MBF for each territory remained consistently statistically significant (P < 0.001) after correcting for multiple comparisons. This study demonstrates the feasibility of measuring MBF and MPR on a segmental basis by single-gated cardiac ASL in normal volunteers. Second, this study demonstrates the feasibility of performing the ASL sequence and T2 -prepared SSFP BOLD imaging during a single adenosine infusion. 2 Technical Efficacy: Stage 1 J. MAGN. RESON. IMAGING 2017;46:413-420.

Segmental quantitative myocardial perfusion with PET for the detection of significant coronary artery disease in patients with stable angina.

The goal of this study is to determine the technical accuracy of segmental perfusion parameters assessed with quantitative cardiac PET imaging in the evaluation of coronary artery disease (CAD) in patients with stable angina. A cohort of patients who participated in the EVINCI protocol underwent an evaluation of coronary anatomy by invasive coronary angiography (ICA) and/or coronary computed tomography angiography (CCTA) and PET myocardial perfusion imaging with H2 (15)O, (13)NH3 or (82)Rb. PET studies were analyzed by two independent observers blinded to clinical and instrumental data, and classified as positive or negative for significant CAD using only segmental perfusion measurements and cut-off values from literature. On a per-patient basis, the overall inter-observer agreement on PET results was 90% (kappa = 0.79), indicating substantial agreement. On a per-vessel basis, the inter-observer agreement on PET results was 88% (kappa = 0.74) in the RCA territory, 94% (kappa = 0.84) in the LAD territory and 94% (kappa = 0.85) in the LCX territory. Segmental PET measurements correctly identified 85% of the patients, resulting in a global sensitivity of 86%, a specificity of 84%, a positive predictive value (PPV) of 69% and a negative predictive value (NPV) of 93%. In vessel-based analyses, quantitative perfusion parameters had a sensitivity, specificity, PPV and NPV of 92%, 82%, 42% and 99%, respectively, for the detection of significant coronary stenoses in all major coronary arteries. The assessment of absolute myocardial perfusion parameters measured at a segment level lead to reliable and accurate identification of patients with significant coronary stenosis at ICA and/or CCTA.

Abstract 15252: Segmental Myocardial Perfusion Improves after Repeated Intramyocardial Cell Injection

Introduction: We previously demonstrated that intramyocardial bone marrow mononuclear cell (MNC) injection improves segmental myocardial perfusion. This study was designed to evaluate in patients with recurrent refractory angina the effect of repeated injection on segmental myocardial perfusion. Methods: Twenty-one patients with recurrent refractory angina pectoris, who received 100x10^6 autologous MNC intramyocardially using the NOGA-system for a second time, were enrolled. Single-photon emission computed tomography was performed at baseline and 3 months after both injection procedures. The myocardium was divided into 17 segments and in both stress and rest images, segmental tracer activity was categorized on a 4-point scale. (1=&gt;75%; 2=50%-74%; 3=25%-49%; 4=&lt;25%) Segments demonstrating increased perfusion of at least 1 point in stress or rest perfusion were categorized as improved. Results: The second injection procedure was 4.6 ± 2.5 years after the first. In total, 139 segments were injected for the first time during either of the procedures, of which 80(58%) segments improved. Repeated injection in the same segment was performed in 45 segments. Of these segments, 18(40%) improved, less than after a first injection (P=0.030). Repeatedly injected segments can be subdivided in 29 previously responding segments (improved after the first injection) and 16 previously non-responding segments (not improved after the first injection). Of the responding segments, 13(45%) segments improved after repeated injection and of the non-responding segments, 5(31%) segments improved. This difference was not significant (P=.476). Conclusions: Segmental myocardial perfusion can improve after repeated intramyocardial MNC injection independently of the effect of the first injection, but the first injection is more effective.

Reproducibility of myocardial perfusion reserve - variations in measurements from post processing using commercially available software.

Adenosine stress first pass cardiac magnetic resonance imaging (CMRI) is a rapidly evolving tool in the diagnosis of ischemic heart disease (IHD). The rest and stress first pass myocardial perfusion data may be interpreted using commercially available software for calculation of time intensity curves in order to generate a numeric value of the segmental or whole heart myocardial perfusion reserve index (MPRI). The objective of this study was to determine the inter- and intra-observer reliability of the data generated by standard commercially available software. Data from 20 adenosine stress CMRI (1.5 T) studies were analyzed using commercially available CAAS MRV 3.3 software (Pie Medical Imaging B.V., Netherlands) for calculation of the MPRI. The stress CMRI was performed using a standardized protocol in 20 women including 10 women with angina and the absence of obstructive CAD and 10 healthy volunteers. MPRI calculation was made in a standardized manner on separate occasions by two independent observers. A single observer repeated the calculation of MPRI three months later, without reference to the prior data. Basal, mid, and apical segments, for the whole myocardium, sub-endocardium, and sub-epicardium were analyzed. Intra-class correlation coefficients (ICC), repeatability coefficients (RC), and coefficients of variation (CoV) were determined. The MPRI results by repeated software measurements were highly correlated, with potentially important variations in measurement observed. The myocardial inter-observer ICC was 0.80 (95% CI, 0.57, 0.92) with a CoV of 7.5%, and intra-observer ICC was 0.89 (95% CI, 0.77, 0.95) with a CoV of 3.6%. The mid-ventricular level MPRI was most reproducible, with intra-observer ICC at 0.91 (95% CI, 0.77, 0.97); intra-observer measurement was more reproducible than inter-observer measurement. There is variation in measurement of MPRI observed in post processing of perfusion data when using a standardized approach and commercially available software. This has implications in the interpretation of data obtained for clinical and research purposes.

No gender difference in the extent of myocardial ischemia in non-ST elevation myocardial infarction

Significant gender differences in angiographic severity of coronary artery disease (CAD) have been demonstrated among patients with non-ST-elevation myocardial infarction (NSTEMI). However, it is unknown if these gender differences are reflected in the extent of myocardial ischemia. We assessed segmental myocardial wall motion and perfusion by contrast echocardiography in 110 patients (34 women and 76 men) with NSTEMI prior to scheduled coronary angiography. The extent of myocardial ischemia using a 17-segment left ventricular (LV) model was compared to quantitative coronary angiography (QCA). Age (70 ± 12 vs 66 ± 12 years), troponin T level (0.53 ± 0.66 vs 0.75 ± 1.32 µg/l), Thrombolysis In Myocardial Infarction (TIMI) risk score (3.2 ± 1.4 vs 3.5 ± 1.4), LV ejection fraction and cardiovascular risk factor burden did not differ between genders. As expected, women had less severe findings on coronary angiography but the extent of myocardial ischemia by contrast echocardiography was comparable in women and men. In multivariable analysis, the risk of having prognostically severe angiographic CAD increased by 29% in women and by 49% in men for every additional LV segment with ischemia, independent of TIMI risk score (both p < 0.01). The present contrast echocardiography study in NSTEMI patients demonstrates that women with NSTEMI have the same extent of LV myocardial ischemia as men in spite of less prevalent angiographic CAD. The findings may help explain why less severe angiographic findings in women with NSTEMI are not accompanied by lower mortality.

Improved quantification in pinhole gated myocardial perfusion SPECT using micro‐CT and ultrasound information

Absolute quantification using single photon emission computed tomography (SPECT) was demonstrated in vitro and in large immobile organs in vivo. To determine the feasibility of in vivo quantification of myocardial perfusion in pinhole gated SPECT, we added an ultrasound derived partial volume correction factor to attenuation and scatter corrections, in combination with gated acquisitions. In nine male Wistar rats, cardiac ultrasound was performed prior to SPECT/CT scans to determine the myocardial wall thickness. SPECT/CT scans were then performed 30 min after injection of (99m) Tc Tetrofosmin. Animals were killed and six midventricular segments of the left ventricle were excised and counted in a γ-well counter. Using AMIDE, regional myocardial activity was measured after combined scatter correction (SC) and attenuation correction (AC). These image derived activities were compared with the ex vivo counted activity. To correct for the partial volume effect, a recovery coefficient was determined from a phantom study, to determine the thickness specific partial volume effect. Combined AC and SC led to a significant underestimation of activity compared with ex vivo data (root mean squared error = 0.145 mCi g(-1)). The recovery coefficient calculated from the phantom study showed a linear relationship with object size from 1 to 6 mm, positioned in the vicinity of the center of the field of view (R(2) = 0.98). Correction of nongated SPECT images with a recovery coefficient derived from the diastolic phase results in a global overestimation with root mean squared error = 0.04 mCi g(-1). Nongated SPECT images corrected with a recovery coefficient with a weighted average ratio diastolic and systolic phase led to an improved root mean squared error of 0.03 mCi g(-1). Combining attenuation correction with scatter correction and a gated partial volume correction yields the best correlation with ex vivo counting (root mean squared error = 0.021 mCi g(-1) (systolic) and 0.025 mCi g(-1) (diastolic). This study demonstrates a method for improved segmental myocardial perfusion quantification in pinhole gated SPECT, using combined attenuation-, scatter- and ultrasound-derived partial volume effect corrections.

Usefulness of Contrast Echocardiography for Predicting the Severity of Angiographic Coronary Disease in Non–ST-Elevation Myocardial Infarction

Guidelines recommend coronary angiography in patients with non-ST-elevation myocardial infarction (NSTEMI) within 24 to 72 hours, a requirement that cannot always be met. The aim of this study was to evaluate the potential use of contrast echocardiography in prioritizing these patients by identifying those with NSTEMI and angiographically severe coronary artery disease (CAD). Echocardiography was performed before coronary angiography in 110 patients with NSTEMI (67 ± 12 years old, 31% women). Segmental myocardial perfusion and wall motion was scored using a 17-segment left ventricular model. CAD was assessed by quantitative coronary angiography. In the total study population, median troponin T level was 0.27 μg/L (0.13 to 0.86) and Thrombolysis In Myocardial Infarction risk score 3.1 ± 1.5. By quantitative coronary angiography 15% had normal coronary angiographic findings, whereas 1-, 2-, and 3-vessel disease were present in 35%, 27%, and 23%, respectively. Severe CAD (left main stem stenosis, 3-vessel disease, or multivessel disease including proximal stenosis in left anterior descending artery) was found in 42%. Number of segments with hypoperfusion increased with CAD severity from 4.1 ± 2.0 in patients with normal coronary arteries to 5.9 ± 2.4, 7.8 ± 3.5, and 10.4 ± 2.8 in patients with 1-, 2-, and 3-vessel disease, respectively (p<0.01). In multiple logistic regression analysis risk of severe CAD increased by 39% for every additional hypoperfused segment by echocardiography independent of wall motion abnormalities and Thrombolysis In Myocardial Infarction risk score. In conclusion, contrast echocardiography may be used for prediction of angiographic CAD severity in patients with NSTEMI awaiting coronary angiography.

Normal myocardial perfusion on 64-detector resting cardiac CT

Computed tomography (CT) of the heart is increasingly used to characterize not only the coronary arteries but also cardiac structure and function. The performance of CT in depicting myocardial perfusion is under active investigation. We describe the pattern of normal myocardial perfusion on resting 64-detector cardiac CT. Patients (n = 33; 20 women, 13 men; mean age, 52 years) with normal radionuclide myocardial perfusion imaging and normal coronary arteries on CT angiography (120 kVp) comprised the study population. Segmental myocardial perfusion on CT was measured in Hounsfield units (HU) with manual and semiautomated methods for the 17-segment American Heart Association model in both systole and diastole. Segments were aggregated into coronary artery territories, from apex to base and by myocardial wall. The relationships between myocardial perfusion and various patient factors were evaluated. Overall mean myocardial perfusion was 98 HU in systole and 94 HU in diastole with the manual method (P = .011) and 92 HU in systole and 95 HU in diastole with the automated method (P = .001). The septum showed significantly higher mean attenuation values than the other walls in systole and diastole with both methods. Generally, attenuation values were lower in the left circumflex artery territory and in the apex. Bivariate analysis showed higher mean myocardial attenuation values for women than men, although this difference did not persist on multivariate analysis adjusted for patient size. Normal mean resting myocardial perfusion correlates with CT attenuation values of approximately 92-98 HU on CT angiography in the coronary arterial phase. The septum consistently shows greater attenuation values than the other walls.

Assessment of Advanced Coronary Artery Disease: Advantages of Quantitative Cardiac Magnetic Resonance Perfusion Analysis

The purpose of this paper was to compare quantitative cardiac magnetic resonance (CMR) first-pass contrast-enhanced perfusion imaging to qualitative interpretation for determining the presence and severity of coronary artery disease (CAD). Adenosine CMR can detect CAD by measuring perfusion reserve (PR) or by qualitative interpretation (QI). Forty-one patients with an abnormal nuclear stress scheduled for X-ray angiography underwent dual-bolus adenosine CMR. Segmental myocardial perfusion analyzed using both QI and PR by Fermi function deconvolution was compared to quantitative coronary angiography. In the 30 patients with complete quantitative data, PR (mean +/- SD) decreased stepwise as coronary artery stenosis (CAS) severity increased: 2.42 +/- 0.94 for <50%, 2.14 +/- 0.87 for 50% to 70%, and 1.85 +/- 0.77 for >70% (p < 0.001). The PR and QI had similar diagnostic accuracies for detection of CAS >50% (83% vs. 80%), and CAS >70% (77% vs. 67%). Agreement between observers was higher for quantitative analysis than for qualitative analysis. Using PR, patients with triple-vessel CAD had a higher burden of detectable ischemia than patients with single-vessel CAD (60% vs. 25%; p = 0.02), whereas no difference was detected by QI (31% vs. 21%; p = 0.26). In segments with myocardial scar (n = 64), PR was 3.10 +/- 1.34 for patients with CAS <50% (n = 18) and 1.91 +/- 0.96 for CAS >50% (p < 0.0001). Quantitative PR by CMR differentiates moderate from severe stenoses in patients with known or suspected CAD. The PR analysis differentiates triple- from single-vessel CAD, whereas QI does not, and determines the severity of CAS subtending myocardial scar. This has important implications for assessment of prognosis and therapeutic decision making.

Therapeutic angiogenesis using naked DNA expressing two isoforms of the hepatocyte growth factor in a porcine acute myocardial infarction model☆

We evaluated the potency of therapeutic angiogenesis using intramyocardial injection of naked DNA expressing two isoforms of hepatocyte growth factor (pCK-HGF-X7) in a porcine myocardial infarction model. Four weeks after left anterior descending coronary artery ligation, 14 pigs were allocated to pCK-Null (negative control, n=7) or pCK-HGF-X7 (n=7) treatment groups. Gated myocardial single photon emission computed tomography was performed 4 and 8 weeks following coronary ligation. The effect of pCK-HGF-X7 on capillary density in the gene-injected myocardium was examined by histological analysis using alkaline phosphatase staining. Segmental myocardial perfusion of the underperfused area (< or =70%) from coronary ligation increased in the pCK-HGF-X7 group (p=0.051), without significant differences in changes over time between the two groups (p=0.54). Systolic wall thickening (p=0.001), left ventricular end-diastolic (p=0.045) and end-systolic volumes (p=0.009), and left ventricular ejection fraction (p=0.041) changed in both groups without significant differences in changes over time between the two groups. The increase in the left stoke volume was higher in the pCK-HGF-X7 group than in the pCK-Null group (p=0.008). Histological analysis showed that capillary density was significantly higher in the pCK-HGF-X7 group than the pCK-Null group (p<0.001). Intramyocardial injection of pCK-HGF-X7 induced significant angiogenesis at infarct-border zone, and increased the left ventricular stroke volume probably caused by reverse remodeling process.

Pilot study to evaluate the safety and feasibility of intracoronary CD133+ and CD133− CD34+ cell therapy in patients with nonviable anterior myocardial infarction

The long-term effect of intracoronary infusion of progenitor cells in patients with chronic ischemic cardiomyopathy. Bone marrow stem-cell administration in patients with myocardial infarction improved myocardial performance and in some studies contributed to favorable left ventricular remodeling. We report on the results of a pilot, single center, controlled safety, and feasibility study, including 24 patients with old, nonviable anterior myocardial infarction. Twelve patients underwent intracoronary administration of selected CD133(+) and CD133(-)CD34(+) progenitor cells and 12 were followed up on medical therapy. Left ventricular volumes and ejection fraction, at rest and during low-dose dobutamine, and myocardial viability, using TL-201 reinjection scintigraphy, were analyzed at baseline and long-term follow-up. Patients in the treatment group experienced a sustained decrease in left ventricular end-diastolic and end-systolic resting volumes (P = 0.008 and P = 0.002, respectively), as well as an improvement in global ejection fraction at rest [from (27.2 +/- 6.8)% to (29.7 +/- 7.3)%, P = 0.016]. Segmental anterior and apical wall perfusion, during TL-201 reinjection, were similarly improved (P = 0.005 and P < 0.001, respectively). One patient developed restenosis at the cell delivery site and one progression of atherosclerosis. During 28.0 +/- 8.7 months of clinical follow-up, only one patient experienced deterioration of heart failure. In the control group, we observed stability in the perfusion defect and deterioration in end-diastolic and end-systolic volumes (P= 0.002 and P = 0.003, respectively) and a nonsignificant decrease in ejection fraction (P = 0.11). Intracoronary infusion of selected CD133(+) and CD133(-)CD34(+) progenitor cells to a previously infarcted and nonviable anterior wall is safe, and results in sustained improvement in segmental myocardial perfusion and in favorable left ventricular remodeling.

747 Infarct size assessment using myocardial contrast imaging, computed tomography and magnetic resonance imaging

Background: Myocardial perfusion imaging and infarct size determinalion using myocardial conlrast echocardiography (MCE), and cardiac magnelic resonance imaging (MRI) are well eslablished lechniques. Presenlly mullislice cardiac compuler lomography (MSCT) is used for morfologic evalualion of the myocardium and coronary arleries, as well as coronary calcium measuremenl. We hypolhesize lhal MSCT could also delermine myocardial perfusion delecls and inlarcl size due I0 reduced contrast enhancemenl ol lhe inlarcled myocardium. Methods: Seven patienls with a firsl ST-elevalion myocardial inlarclion (MI), and positive myocardial enzymes who were treated with primary perculaneous coronary intervention were included. Within 7 days el lhe MI all palienls had a MCE (real time and Iriggered imaging wilh sonovue), MRI for perlusion using delayed contrasl enhancement, and a cardiac MSCT study. To assess myocardial pedusion delecls on MSCT, the window levels el lhe examinalion were visually adjusled to maximize the difference between conlrast enhanced and less enhanced lissue. Colour coding was performed according to the Houesfield unils el myocardial tissue Io furlher discriminale between transmural diflrences in perfusion. The lell ventricle was divided into 17 segments, and lor each lechnique performed lhe segmental myocardial perfusion was classified as 0: normal, 1 : less than 50% Iransmuralily el perfusion delecl, 2: more than 50% Iransmurality or, 3: transmural delecl. The scoring was done by 3 blinded independent observers. Results: Wall motion abnormalilies were associaled with perfusion delesls observed wilh MCE and MRI. There was moderale agreement belween MRI and MSCT for perlusion delecls al 74% (kappa = 0.48), a good agreemenl between MCE and MSCT al 86% (kappa = 0.60), and a very good concordance between combined MCE and MRI findings Versus MSCT al a kappa value el 0.66 (agreement al 89%). The sensilivity and specificily el MSCT Io assess myocardial pedusion was respeclively, 86% and 85% Conclusion: MSCT appears to be a promising technique to simullaneously assess myocardial and coronary artery morfology as well as segmenlal myocardial perfusion to delermine inlarcl size.

Disfunção erétil: um marcador para alterações da perfusão miocárdica?

To study the correlation between erectile dysfunction (ED) and myocardial perfusion impairment in men with suspected or diagnosed coronary artery disease (CAD). In this prospective study a self-administered IIEF-5 questionnaire was answered by 287 patients that underwent myocardial perfusion imaging under both resting and stress condition with technetium-99m sestamibi, through gated SPECT nuclear scintigraphy technique, before and after physical or pharmacological stress. Some degree of erectile dysfunction (group ED+) was found in 137 (47.8%) patients and in these, age was significantly higher (60.60+/-9.84 vs 50.67+/-9.94 - p<0.001)) than in those without erectile dysfunction (group ED-). In the ED+ group, it was observed a higher prevalence of hypertension, diabetes, myocardial infarction (MI) and percutaneous coronary angioplasty (PCTA). Regardless of the age factor, ED+ patients also presented higher occurrence of myocardial perfusion impairment (necrosis and/or ischemia) and left ventricular systolic wall motion and thickening abnormalities. Patients with ED have higher estimated probability of presenting segmental myocardial perfusion and functional contraction impairment and, therefore, CAD, independent of the aging factor. The authors conclude that ED may be considered not only a marker for CAD but also a condition related to the occurrence of major coronary events such as MI and PCTA.

Bone Marrow-Derived Cell Mobilization with G-CSF and GM-CSF in Patients with Acute Myocardial Infarction: A Pilot Study on Feasibility, Safety and Efficacy.

Introduction. Intracoronary or intramyocardiac injection of bone marrow stem cells or growth factor-mobilized peripheral blood stem cells (PBSC) may contribute to myocardial regeneration and neovascularization of the ischemic myocardium either in animal models or in human. This effect is probably due to a selective colonization of the ischemic area by PBSC. Very few studies were done in the acute setting of ischemic heart disease, with controversial results. Aims of this pilot study were: i) to verify feasibility and safety of PBSC mobilization in patients with acute myocardial infarction (AMI); ii) to monitor clinical effects of PBSC mobilization in terms of global and segmental myocardial perfusion and function.Patients and methods. Eight male patients (mean age: 51,7±5,6 years) were enrolled. All were treated with a primary percutaneous transluminal coronary angioplasty (PTCA) for an anterior (5 patients) or an inferior (3 patients) AMI. The mobilization regimen consisted of G-CSF 5 μg/kg/12h from day 1 to day 3 and GM-CSF 2.5 μg/kg/24h from day 1 to day 5 (starting within 24 hours from PTCA). Since transient severe hypotension was noticed in the first three patients, the protocol was amended by reducing and tapering GM-CSF administration (2.5 μg/kg/24h at days 3, 5, 7). All patients underwent coronary angiography, intracoronary doppler flow study, echocardiography, and nuclear Thallium scan before treatment and at 6 months apart.Results. WBC and PBSC peaked during the 3th day of mobilization. Mean WBC and PBSC peaks were 34960± 10794 leukocytes/μL and 29.71± 30.8 CD34+/μL. Five in hospital adverse events were recorded: severe hypotension in 3 patients (as previously mentioned), atrial fybrillation in 1 patient, recurrent ischemia in 1 patients. No death was observed. At present 7 patients completed a 6-months follow-up evaluation: target lesion revascularization rate was 14,3% (1 patient) and target vessel revascularization rate was 42,8% (3 patients). Angiographic mean ejection fraction increased from 49,8±11,9 to57,1±8,9 (p=NS), and mean coronary flow reserve raised from 1,63±0,42 to 2,45±0,36 (p=0,005). Perfusion improvement was observed by nuclear study in 66% of patients.Conclusions. We conclude that: a) cytokine-induced stem cell mobilization is feasible in AMI patients with adequate GM-CSF administration; b) myocardial perfusion appears to improve within the first six months of follow-up; c) the 3 cases of progressive coronary disease give a concern about a potential negative effect of hematopoietic cytokines (particularly GM-CSF) on silent coronary lesions. However, PBSC mobilization using G-CSF only is worthwhile of further investigation.

The effect of kidney transplant on cardiac function: an echocardiographic perspective.

Kidney transplant (KT) resolves many of the cardiac abnormalities associated with chronic kidney failure (CKF). This study analyzed cardiac alterations of kidney failure and their modification with transplant. Thirteen patients in CKF underwent conventional echocardiograms, dobutamine stress echocardiograms, and injection of contrast to examine perfusion before KT and 3 months after transplant. Nine patients had evidence of left ventricular hypertrophy and six had evidence of diastolic dysfunction. Wall thickness, left ventricular mass, and mass index diminished after KT; only two patients continued to manifest hypertrophy. Left ventricular systolic diameters and volumes diminished at 3 months, and diastolic diameters after 4 months. Left ventricular fractional shortening and ejection fraction increased 3 months after transplant. At the end of the study, only two patients continued to show diastolic dysfunction. Dobutamine echocardiograms showed no segmental wall-movement abnormalities. Myocardial perfusion was normal before and after transplant. The results suggest that KT diminishes hypertrophy and improves left ventricular systolic and diastolic function. Echocardiography provides valuable information for detection and follow-up of cardiac abnormalities in patients with kidney disease. Evaluation of segmental wall movement and myocardial perfusion aid in demonstrating that our studied patients with CKF had no indirect signs of coronary artery disease.

Frequency and clinical implications of fluid dynamically significant diffuse coronary artery disease manifest as graded, longitudinal, base-to-apex myocardial perfusion abnormalities by noninvasive positron emission tomography.

Diffuse coronary atherosclerosis is the substrate for plaque rupture and coronary events. Therefore, in patients with mild arteriographic coronary artery disease without significant segmental dipyridamole-induced myocardial perfusion defects, we tested the hypothesis that fluid dynamically significant diffuse coronary artery narrowing is frequently manifest as a graded, longitudinal, base-to-apex myocardial perfusion abnormality by noninvasive PET. In this study, 1001 patients with documented coronary artery disease by coronary arteriography showing any visible coronary artery narrowing underwent rest-dipyridamole PET perfusion imaging. Quantitative severity of dipyridamole-induced, circumscribed, segmental PET perfusion defects was objectively measured by automated software as the minimum quadrant average relative activity indicating localized flow limiting stenoses. Quantitative severity of the graded, longitudinal, base-to-apex myocardial perfusion gradient indicating fluid dynamic effects of diffuse coronary artery narrowing was objectively measured by automated software as the spatial slope of relative activity along the cardiac longitudinal axis. In patients with mild arteriographic disease without statistically significant dipyridamole-induced segmental myocardial perfusion defects caused by flow-limiting stenoses compared with normal control subjects, there was a graded, longitudinal, base-to-apex myocardial perfusion gradient significantly different from normal control subjects (P=0. 001) that was also observed for moderate to severe dipyridamole-induced segmental perfusion defects (P=0.0001), indicating diffuse disease underlying segmental perfusion defects; 43% of patients with or without segmental perfusion defects demonstrated graded, longitudinal, base-to-apex perfusion abnormalities beyond +/-2 SD of normal control subjects, indicating diffuse coronary arterial narrowing by noninvasive PET perfusion imaging.

Segmental myocardial contractility versus perfusion in Kawasaki disease with coronary arterial aneurysm

The impact of Kawasaki-related coronary injury on the myocardium was evaluated in 13 patients with persistent coronary aneurysm after a follow-up period of 7.92 ± 3.97 years (range 1.8 to 14.3). Myocardial segmental perfusion and contractility integrity were assessed by resting and exercise echocardiography and technetium-99 (Tc-99m) sestamibi scan. Eight patients (61.5%) had giant aneurysms (≥8 mm) and 9 had multivessel involvement; the mean diameter of the largest aneurysm was 8.6 ± 2.5 mm (range 5 to 14). During the acute phase, myocardial infarction occurred in 1 patient and coronary thrombosis in another. At the latest echocardiographic evaluation, the mean aneurysm diameter was 6.8 ± 2.4 mm (range 4.5 to 12), there was persistent giant aneurysms in 5 of 8 patients, and 3 of 9 patients had multivessel involvment. Coronary angiography demonstrated stenosis in 7 of 10 patients, with multiple levels in 2. At sestamibi scan, all 13 patients had perfusion anomalies at rest, whereas only 7 had detectable hypokinesia on echocardiography. With exercise, perfusion returned to near normal in 3 patients, improved in 3, remained unchanged in 4, and worsened in 3 patients. Segmental contractility similarly deteriorated in the latter 3 patients but also in 2 patients whose perfusion scan had improved with exercise. Three patients, normal at rest, developed segmental hypokinesia during exercise. When present, the location of observed changes in contractility on stress echocardiography corresponded to that of perfusion defect. In conclusion, abnormal myocardial perfusion is present long term after complicated Kawasaki disease, the worst anomalies accompanying persistent giant aneurysms. Unfavorable perfusion response was coupled with abnormal contractility; however, enhanced perfusion with exercise correlated poorly with segmental contractility response.