Current Awareness and Use of the Strain Echocardiography in Routine Clinical Practices: Result of a Nationwide Survey in Korea

BACKGROUND: Because conventional echocardiographic parameters have several limitations, strain echocardiography has often been introduced in clinical practice. However, there are also obstacles in using it in clinical practice. Therefore, we wanted to find the current status of awareness on using strain echocardiography in Korea. METHODS: We conducted a nationwide survey to evaluate current use and awareness of strain echocardiography from the members of the Korean Society of Echocardiography. RESULTS: We gathered total 321 questionnaires from 25 cardiology centers in Korea. All participants were able to perform or interpret echocardiographic examinations. All participating institutions performed strain echocardiography. Most of our study participants (97%) were aware of speckle tracking echocardiography and 185 (58%) performed it for clinical and research purposes. Two-dimensional strain echocardiography was the most commonly used modality and left ventricle (LV) was the most commonly used cardiac chamber (99%) for clinical purposes. Most of the participants (89%) did not think LV strain can replace LV ejection fraction (LVEF) in their clinical practice. The common reasons for not performing routine use of strain echocardiography was diversity of strain measurements and lack of normal reference value. Many participants had a favorable view of the future of strain echocardiography. CONCLUSION: Most of our study participants were aware of strain echocardiography, and all institutions performed strain echocardiography for clinical and research purposes. However, they did not think the LV strain values could replace LVEF. The diversity of strain measurements and lack of normal reference values were common reasons for not using strain echocardiography in clinical practice.

Horseshoe-like Shaped Atrial Septal Defects Confirmed on Three-Dimensional Transesophageal Echocardiography

No abstract available.

Time Variance of Electrocardiographic Transmural Dispersion in Acute Myocardial Infarction

BACKGROUND AND OBJECTIVES: The mechanism responsible for lethal ventricular arrhythmia (LVA) after acute myocardial infarction (AMI) remains unclear. SUBJECTS AND METHODS: The corrected QT interval (QTc) and interval from the peak to the end of the T wave (TpTe) were measured, which indicated myocardial transmural dispersion of repolarization (TDR) in 72 patients with AMI. TpTe was also expressed as a corrected value, [TpTe/QTe]x100% and TpTe/√RR. These parameters were obtained from all the 12-leads of electrocardiography after arrival at the hospital, just before and after percutaneous coronary intervention (PCI), and at 4, 24, and 48 hours and 5 days after PCI. RESULTS: Analyzing with repeated measures analysis of variance, the TpTe, [TpTe/QTe]x100% and TpTe/√RR after AMI showed significant changes in time variance. The patients were divided into LVA (17 patients, 24%) and non-LVA group (55 patients, 76%). The [TpTe/ QTe]×100% (V₂: 25±7% vs. 22±5%, p=0.036) and TpTe/√RR (V₂: 109 ± 42 ms vs. 88 ± 22 ms, p=0.05, V₃: 108±39 ms vs. 91±27 ms, p=0.048) in V₂ and V₃ leads were prolonged in the LVA group after PCI. The [TpTe/QTe]×100% (28±9 % vs. 22±5%, p=0.025) and TpTe/√RR (129±53 ms vs. 99±41 ms, p=0.05) in V₃ lead were prolonged in the LVA group 24 hours after PCI. CONCLUSION: The mechanisms responsible for LVA after AMI may be associated with increased TDR, and PCI may have an important role in reducing LVA.

Impact of the beta-1 adrenergic receptor polymorphism on tolerability and efficacy of bisoprolol therapy in Korean heart failure patients: association between beta adrenergic receptor polymorphism and bisoprolol therapy in heart failure (ABBA) study

BACKGROUND/AIMS: We evaluated the association between coding region variants of adrenergic receptor genes and therapeutic effect in patients with congestive heart failure (CHF). METHODS: One hundred patients with stable CHF (left ventricular ejection fraction [LVEF] < 45%) were enrolled. Enrolled patients started 1.25 mg bisoprolol treatment once daily, then up-titrated to the maximally tolerable dose, at which they were treated for 1 year. RESULTS: Genotypic analysis was carried out, but the results were blinded to the investigators throughout the study period. At position 389 of the beta-1 adrenergic receptor gene (ADRB1), the observed minor Gly allele frequency (Gly389Arg + Gly389Gly) was 0.21, and no deviation from Hardy-Weinberg equilibrium was observed in the genotypic distribution of Arg389Gly (p = 0.75). Heart rate was reduced from 80.8 +/- 14.3 to 70.0 +/- 15.0 beats per minute (p < 0.0001). There was no significant difference in final heart rate across genotypes. However, the Arg389Arg genotype group required significantly more bisoprolol compared to the Gly389X (Gly389Arg + Gly389Gly) group (5.26 +/- 2.62 mg vs. 3.96 +/- 2.05 mg, p = 0.022). There were no significant differences in LVEF changes or remodeling between two groups. Also, changes in exercise capacity and brain natriuretic peptide level were not significant. However, interestingly, there was a two-fold higher rate of readmission (21.2% vs. 10.0%, p = 0.162) and one CHF-related death in the Arg389Arg group. CONCLUSIONS: The ADRB1 Gly389X genotype showed greater response to bisoprolol than the Arg389Arg genotype, suggesting the potential of individually tailoring beta-blocker therapy according to genotype.

Usefulness of Hyperemic Microvascular Resistance Index as a Predictor of Clinical Outcomes in Patients with ST-Segment Elevation Myocardial Infarction

BACKGROUND AND OBJECTIVES: Microvascular function is a useful predictor of left ventricular functional changes in patients with ST-segment elevation myocardial infarction (STEMI). We evaluated the usefulness of the hyperemic microvascular resistance index (hMVRI) for predicting long-term major adverse cardiovascular events (MACEs) in patients with STEMI assessed immediately after primary percutaneous coronary intervention (PCI). SUBJECTS AND METHODS: hMVRI were evaluated in 145 patients with first acute STEMI treated with primary PCI using an intracoronary Doppler wire. hMVRI was defined as the ratio of mean aortic pressure over hyperemic averaged peak velocity of infarct-related artery. Major adverse cardiovascular events (MACEs) included cardiac death and re-hospitalization for congestive heart failure. RESULTS: During the mean follow-up of 85+/-43 months, MACEs occurred in 17.2% of patients. Using a receiver-operating characteristics analysis, hMVRI >2.82 mm Hg.cm-1.sec (sensitivity: 87%; specificity: 69%; and area under curve: 0.818) was the best cut-off values for predicting future cardiac events. The Cox proportional hazard analysis showed that hMVRI was an independent predictor for long-term MACEs (hazard ratio 1.741, 95% confidence interval 1.348-2.264, p2.82 mm Hg.cm-1.sec (p<0.001). CONCLUSION: hMVRI was a strong predictor of long-term MACEs in patients with STEMI treated with primary PCI.

Effects of intensive versus mild lipid lowering by statins in patients with ischemic congestive heart failure: Korean Pitavastatin Heart Failure (SAPHIRE) study

BACKGROUND/AIMS: This study was designed to evaluate the dose-effect relationship of statins in patients with ischemic congestive heart failure (CHF), since the role of statins in CHF remains unclear. METHODS: The South koreAn Pitavastatin Heart FaIluRE (SAPHIRE) study was designed to randomize patients with ischemic CHF into daily treatments of 10 mg pravastatin or 4 mg pitavastatin. RESULTS: The low density lipoprotein cholesterol level decreased by 30% in the pitavastatin group compared with 12% in the pravastatin (p < 0.05) group. Left ventricular systolic dimensions decreased significantly by 9% in the pitavastatin group and by 5% in the pravastatin group. Left ventricular ejection fraction (EF) improved significantly from 37% to 42% in the pitavastatin group and from 35% to 39% in the pravastatin group. Although the extent of the EF change was greater in the pitavastatin group (16% vs. 11%) than that in the pravastatin group, no significant difference was observed between the groups (p = 0.386). Exercise capacity, evaluated by the 6-min walking test, improved significantly in the pravastatin group (p < 0.001), but no change was observed in the pitavastatin group (p = 0.371). CONCLUSIONS: Very low dose/low potency pravastatin and high dose/high potency pitavastatin had a beneficial effect on cardiac reverse remodeling and improved systolic function in patients with ischemic CHF. However, only pravastatin significantly improved exercise capacity. These findings suggest that lowering cholesterol too much may not be beneficial for patients with CHF.

Impact of Arterial Stiffness on Regional Myocardial Function Assessed by Speckle Tracking Echocardiography in Patients with Hypertension

BACKGROUND: Arterial stiffening may affect regional myocardial function in hypertensive patients with normal ejection fraction (EF). METHODS: Brachial-ankle pulse wave velocity (PWV) was measured in 70 patients, of mean age 48 +/- 14 years, with untreated hypertension and EF > 55%. Using two-dimensional-speckle tracking echocardiography, we measured longitudinal and circumferential strain (epsilon) and strain rate (SR). Basal and apical rotations were measured using short axis views. RESULTS: The mean systolic and diastolic blood pressure in these patients was 152 +/- 15 mmHg and 92 +/- 11 mmHg, respectively. The mean value of PWV was 1578 +/- 274 cm/s. PWV significantly correlated with age (r = 0.682, p 1700 cm/s compared to those with PWV < or = 1400 cm/s or those with PWV 1400-1700 cm/s. CONCLUSION: In hypertensive patients with normal ejection fraction, arterial stiffening contributes to impaired systolic and diastolic function of the regional myocardium. Compensatory increases in ventricular twist were diminished in patients with advanced stage of vascular stiffening.

Is the Measurement of Epicardial Fat in Obese Adolescents Valuable?

No abstract available.

Rho-Associated Kinase 2 Polymorphism in Patients With Vasospastic Angina

BACKGROUND AND OBJECTIVES: Recent studies indicate that in response to vasoconstrictor stimuli, the small GTPase RhoA and its down-stream effector, Rho-associated kinase 2 (ROCK)/Rho-kinase, are associated with hypercontraction of the vascular smooth muscle of coronary arteries through augmentation of myosin light chain phosphorylation and Ca2+ sensitization. Expression of ROCK/Rho-kinase mRNA was significantly increased and up-regulated in the spastic coronary artery in a porcine model, and a specific inhibitor of ROCK/Rho-kinase inhibited coronary artery spasm in humans. We therefore explored the role of ROCK2 polymorphisms in the pathogenesis of vasospastic angina (VA). SUBJECTS AND METHODS: We studied 106 patients with VA who exhibited spontaneous or provoked coronary spasm during coronary angiography and compared the prevalence of ROCK2 polymorphisms between this group of patients with VA and controls whose angiograms were normal, and in whom the ergonovine test did not cause spasm (n=107). Five single nucleotide polymorphisms (SNPs) of the ROCK2 gene were selected. SNPs were genotyped by high-resolution melting. Linkage disequilibrium and haplotype analyses were performed using the SHEsis program. RESULTS: The prevalence of genotypes of the 5 interesting SNPs in patients with VA was not different from that in the control group. In haplotype analysis, the haplotype G-T-C-T-G (in order of rs978906, rs2271621, rs2230774, rs1515210, and rs3771106) was significantly associated with a decreased risk of VA (p=0.007). CONCLUSION: The haplotype G-T-C-T-G in the ROCK2 gene had a protective effect against VA, suggesting the involvement of ROCK2 in VA pathogenesis.

Validation of Three-Dimensional Echocardiography for Quantification of Aortic Root Geometry: Comparison with Multi-Detector Computed Tomography

BACKGROUND: Three-dimensional (3D) echocardiography has been reported to be valuable for evaluating the geometry of cardiac chambers. We validated the accuracy of 3D transthoracic echocardiography for quantifying aortic root geometry in comparison with cardiac multi-detector computed tomography (MDCT). METHODS: Twenty-three patients who underwent cardiac MDCT and showed normal left ventricular ejection fraction (> 55%), as assessed by 2-dimensional transthoracic echocardiography, were enrolled (12 male, mean 53 +/- 9 years). We defined the aortic root volume as the volume from the aortic annulus to the sinotubular junction. The aortic root volume at end-diastole measured by both cardiac MDCT and 3D echocardiography was assessed. RESULTS: The cross-sectional area of the aortic root was asymmetric. At the annulus level, the cross-sectional area showed asymmetric triangle. From the aortic annulus to the most dilated point of the sinus of Valsalva, the asymmetric triangular shape was maintained. From the most dilated point of the sinus of Valsalva to the sinotubular junction, the cross-sectional shape of the aortic root changed to oval. The average aortic root volumes measured by 3D echocardiography (ARV-3DE) were 13.6 +/- 4.8 mL at end-diastole and 14.1 +/- 5.3 mL at end-systole, respectively. The average aortic root volume measured by MDCT at end-diastole (ARV-CT) was 14.1 +/- 5.7 mL. At end-diastole, the ARV-3DE correlated well with the ARV-CT (R2 = 0.926, difference = 0.5 +/- 1.7 mL), and the two methods were in excellent agreement (the percent difference was 0%). CONCLUSION: Our results demonstrate both the feasibility and accuracy of 3D echocardiography for the clinical assessment of the geometry of the aortic root.

Morning Hypertension in Treated Hypertensives: Baseline Characteristics and Clinical Implications

BACKGROUND AND OBJECTIVES: Morning hypertension is closely related to target organ damage and cardiovascular events. Little data is available concerning the baseline characteristics and comprehensive blood pressure analysis of hypertensive patients on treatment with morning hypertension. SUBJECTS AND METHODS: We evaluated 1,087 hypertensive patients who had taken stable anti-hypertensive medication at least 6 months. The enrolled patients measured their home blood pressure for 7 days. Baseline characteristics and the laboratory data were analyzed. Morning hypertension was defined as a morning blood pressure > or =135/85 mm Hg and systolic or diastolic blood pressure difference between morning and evening exceeding 10 mm Hg. RESULTS: One hundred seventy three patients with morning hypertension showed a preponderance of males, older patients, alcohol consumers, and greater waist circumference and waist-to-hip ratio despite the same body mass index. Impaired fasting glucose and metabolic syndrome were more prevalent in the patients with morning hypertension. The morning hypertensives took more anti-hypertensive drugs and displayed higher blood pressure in the clinic and at home. CONCLUSION: The worse clinical variables and relatively poorly controlled blood pressure of those with morning hypertension supports a potential relationship of morning hypertension with poor cardiovascular outcome. Morning blood pressure should be monitored at home for the optimal treatment of hypertension.

Differential Relationship between Metabolic Syndrome Score and Severity of Coronary Atherosclerosis as Assessed by Angiography in a Non-Diabetic and Diabetic Korean Population

Whether the metabolic syndrome (MetS) has prognostic value for coronary artery disease (CAD) beyond its individual components is controversial. We compared the relationship between the number of MetS components and CAD severity as assessed by angiography in non-diabetic and diabetic subjects. We consecutively enrolled 527 patients who underwent their first coronary angiography. Patients were divided into four groups according to the number of MetS components: 0/1, 2, 3, and 4/5. A coronary atherosclerosis score was used to quantify the extent of atherosclerotic involvement. The relationship between the MetS score and angiographic CAD severity or clinical presentation was compared between non-diabetic and diabetic subjects. Individuals with the MetS (n = 327) had a higher prevalence of CAD (60% vs 32%, P < 0.001), multi-vessel disease (34% vs 16%, P < 0.001), and acute coronary syndromes (49% vs 26%, P < 0.001) than those without the MetS. In the non-diabetic group, atherosclerosis score increased with the MetS score (1.0 +/- 2.1, 2.0 +/- 2.9, 2.8 +/- 2.9, and 3.6 +/- 3.9, P < 0.001) whereas there was no significant difference in the diabetic group (0.5 +/- 1.0, 5.2 +/- 4.7, 4.2 +/- 2.9, and 4.4 +/- 3.5, P = 0.102). The MetS score is related to CAD severity in non-diabetic patients but the association between the MetS score and angiographic CAD severity may be obscured in the presence of diabetes.

Characteristics and Predictors of Masked Hypertension in Elderly Patients with Well-controlled Hypertension

BACKGROUND: Clinic-based blood pressure measurements may lead to untoward results in the management of hypertension. Masked hypertension (MH) has been shown to be related to a poor prognosis due to its hidden nature. The purpose of this study is to present the clinical predictors of MH in elderly patients over 65 years with well-controlled clinic blood pressure (CBP) and to evaluate the gap, the 'mask effect' (negative white-coat effect), between CBP and home blood pressure (HBP). METHODS: The BPs of 1,019 treated hypertensive patients were measured by a doctor at an out-patient clinic and by patients themselves at home. Clinical parameters for MH were analyzed in 511 patients with well-controlled CBP (45.6% men, mean age 57.1+/-9.0 years). RESULTS: Among the patients over 65 years (n=113, 46.8% men, mean age 68.4+/-7.3 years) and with well-controlled CBP, the prevalence of MH was 26.5% (30 patients). In multivariate-adjusted analysis, the risk of MH increased with physical inactivity (odds ratio [OR], 2.942; 95% confidence interval [CI], 1.039-8.329; p=0.042), use of beta-blocker (OR, 4.242; 95% CI, 1.528-11.785; p=0.06) and systolic clinic BP (OR, 1.083; 95% CI, 0.017-1.154; p=0.013). Furthermore, HBP correlated well with CBP (r=0.329; p<0.001) and further with degree of ME (r=0.723; p<0.001). CONCLUSION: In looking for MH, it would be useful to carefully assess patients taking beta-blockers, having higher CBP, and who are physically inactive by using self-monitoring home or ambulatory BP monitoring.

Long Journey of Sclerosant From the Esophagus to the Right Atrium

A 34-year-old man, who had been treated with an endoscopic injection of a mixture of n-butyl-2-cyanoacrylate (Histoacryl) and Lipiodol for control of variceal bleeding 6 months previously, presented with an intracardiac mass in the right atrium (RA). Two-dimensional echocardiography revealed an intracardiac mass in the RA that appeared to extend from the inferior vena cava. The origin of the sclerosant was traced by computed tomography (CT). This is a very rare case in which the sclerosant migration route was demonstrated by CT scan. The findings of this case suggest that the systemic migration of sclerosant into an intracardiac chamber should be considered in patients with an intracardiac mass, especially with a history of previous sclerotherapy for variceal bleeding.

Unusual Aortic Dissection Mimicking Penetrating Atherosclerotic Ulcer after Blunt Chest Trauma

No abstract available.

Acute Mitral Regurgitation due to Spontaneous Chordal Rupture in a Patient With Obstructive Hypertrophic Cardiomyopathy

A 69-year-old male presented with obstructive hypertrophic cardiomyopathy, mitral valve regurgitation, and myxomatous mitral valve prolapse. A spontaneous chordal rupture and acute severe mitral regurgitation resulted in abrupt clinical deterioration despite complete relief of severe left ventricular outflow tract obstruction and systolic anterior motion of the anterior mitral leaflet. The patient underwent extensive cardiac surgery due to intractable heart failure. Surgical procedures included a mitral valve replacement, a septal myectomy, and the Maze procedure.

Correlation Between the Serum Bilirubin Level and the Coronary Microvascular Integrity in Diabetic Patients

BACKGROUND AND OBJECTIVES: Bilirubin has a protective role in suppressing atherosclerosis and coronary artery disease by its potent physiological antioxidant properties. There has been no comparative study on the relation between the bilirubin level and the coronary microvascular function in diabetic patients. This study investigated whether the bilirubin level correlates with the coronary microvascular integrity in diabetes by assessing the coronary flow velocities after successful percutaneous coronary intervention (PCI). SUBJECTS AND METHODS: Fifty patients (31 males and 19 females, mean age 60+/-11) with angina and who received elective PCI were studied. Using an intracoronary Doppler wire, the coronary flow velocity reserve (CFR), the hyperemic microvascular resistance index and the phasic coronary flow velocity patterns were measured after PCI. RESULTS: The mean value of the fasting blood glucose was 211+/-88 mg/dL, the man value of glycated hemoglobin A1c (HbA1c) was 8.1+/-1.6% and the mean serum total bilirubin level was 0.59+/-0.21 mg/dL. CFR was significantly correlated with the serum bilirubin level (r=0.485, p<0.001), HbA1c (r=-0.432, p=0.003) and the fasting blood glucose (r=-0.361, p=0.011). On multivariate analysis, HbA1c, bilirubin and left ventricular hypertrophy showed independent relationships with coronary microvascular dysfunction (p=0.003, p=0.004, p=0.033, respectively). CONCLUSION: These results suggest that glycemic control and elevated serum bilirubin may protect diabetic patients from coronary microvascular dysfunction.

A Case of Huge Coronary Aneurysm After Implantation of a Sirolimus-Eluting Stent

This report describes the case of a 62-year-old woman who was previously diagnosed with stable angina. Coronary angiography revealed clinically significant stenosis in the middle of the left anterior descending (LAD) artery, the first diagonal branch, the distal left circumflex (LCX) artery and the proximal posterior descending artery (PDA). After administering aspirin and clopidogrel, the patient underwent implantation of sirolimus-eluting stents in the middle LAD artery and the first diagonal branch. Bare-metal stents were implanted in the distal LCX artery and the proximal PDA. Nineteen months later, follow-up coronary angiography revealed aneurysmal dilation at the middle LAD artery and the first diagonal branch. Forty-six months after implantation of the sirolimus-eluting stents, the size of the coronary aneurysm had increased to 12.4 mm; however, no sign of aneurysmal dilatation was observed at the bare-metal stent sites. This suggested that the implantation of the sirolimus-eluting stent was partially responsible for causing the coronary aneurysm.

Echocardiographic Plains Reflecting Total Amount of Epicardial Adipose Tissue as Risk Factor of Coronary Artery Disease

BACKGROUND: Several studies suggested that epicardial adipose tissue (EAT) might be associated with metabolic syndrome and coronary atherosclerosis. But, little had been studied whether the thickness of EAT on echocardiography could represent the whole amount of EAT. The purpose of this study was to identify the best echocardiographic methods reflecting total amount of EAT. \METHODS: Sixty subjects (32 women, mean: 58+/-12 years-old) who underwent 64-slice multidetector computed tomography (MDCT) were consecutively enrolled. All CT scanning was performed one Brilliance CT-64-channel configuration scanner (Philips, Cleveland, USA) and axially contiguous 10-mm-thickeness sections were obtained from aortic valve to diaphragm level. EAT area was manually traced in each slice and summed up. The EAT thickness was measured as the echo-lucent or echo-dense space between epicardium and pericardium at parasternal long-axis, modified 4-chamber, and apical 4-chamber view. RESULTS: The EAT thickness at parasternal long-axis and modified 4-chamber view and the sum of EAT thickness from each views (median thickness: 1.0, 2.8, 1.1 and 5.0 mm, respectively) were all correlated with total EAT area on MDCT. Among echo parameters, the EAT thickness measured on parasternal long-axis view during diastole correlated best with total EAT area on MDCT (r=0.572, p<0.001). CONCLUSION: The echocardiographic EAT measurement might be easily accessible and less harmful method representing whole amount of EAT. The measurement of the thickness of EAT on parasternal long-axis view during diastole by echocardiography might be feasible and reliable in the studying field of EAT.

A Novel Index of Microcirculatory Resistance for Invasively Assessing Myocardial Viability after Primary Angioplasty for Treating Acute Myocardial Infarction: Comparison with FDG-PET Imaging

BACKGROUND AND OBJECTIVES: The state of the coronary microcirculation is an important determinant of the myocardial viability and clinical outcomes for patients suffering with acute myocardial infarction (AMI). However, there are scant comparative studies on the most reliable invasive, on-site measurement for assessing the microvascular integrity and myocardial viability in AMI patients. The aim of this study is to evaluate the usefulness of a novel index of microcirculatory resistance (IMR) and the coronary physiologic parameters for predicting the myocardial viability after primary percutaneous coronary intervention (PCI) in AMI patients. SUBJECTS AND METHODS: Twenty-four patients (21 males, mean age: 55+/-11 years) underwent primary PCI for AMI (LAD: 17, RCA: 6, LCX: 1) were enrolled. After successful PCI, using a pressure-temperature sensor-tipped coronary wire, the thermodilution-derived CFR (CFRthermo) and coronary wedge pressure (Pcw) were measured and the ratio of the Pcw and the mean aortic pressure (Pcw/Pa) was calculated, along with the IMR, which was defined as the distal coronary pressure divided by the inverse of the hyperemic mean transit time. 18F-fluorodeoxyglucose (FDG) PET was performed after primary PCI at 7 days post-AMI to evaluate the myocardial viability by the regional percentage of FDG uptake in the infarct-related segments. RESULTS: There were good correlations between all the coronary pressure measurements and the regional FDG uptake (CFRthermo, r=0.454, p=0.026; Pcw, r=-0.407, p=0.048; Pcw/Pa, r=-0.480, p=0.018; IMR, r=-0.696, p<0.001, respectively). Multiple logistic regression analysis demonstrated that the IMR was an adjusted predictor for myocardial viability as defined by the 50% FDG-PET threshold value among all the coronary pressure measurements (OR=0.884, p=0.021). The cut-off value of IMR for predicting myocardial viability was 22 U (a sensitivity of 82%, a specificity of 85% and an accuracy of 85%). CONCLUSIONS: Intracoronary pressure wire-based indexes are useful for on-site assessment of myocardial viability after primary PCI. IMR is a novel index that represents the microvascular integrity, and it is a better predictor of myocardial damage than the current techniques for evaluating the microvasculature after primary PCI.