Impact of Atrial Fibrillation on Patients Undergoing Transcatheter Aortic Valve Implantation (TAVI): The K-TAVI Registry

Purpose@#The incidence and prognostic implications of atrial fibrillation (AF) in patients with severe aortic stenosis (AS) undergoing transcatheter aortic valve implantation (TAVI) are controversial, especially for Korean patients. Furthermore, the pattern of antithrombotic therapy for these patients is unknown. The present study sought to identify the impact of AF on Korean patients undergoing TAVI and demonstrate the status of antithrombotic therapy for these patients. @*Materials and Methods@#A total of 660 patients who underwent TAVI for severe AS were recruited from the nationwide K-TAVI registry in Korea. The enrolled patients were stratified into sinus rhythm (SR) and AF groups. The primary endpoint was all-cause death at 1-year. @*Results@#AF was recorded in 135 patients [pre-existing AF 108 (16.4%) and new-onset AF 27 (4.1%)]. The rate of all-cause death at 1 year was significantly higher in patients with AF than in those with SR [16.2% vs. 6.4%, adjusted hazard ratio (HR): 2.207, 95% confidence interval (CI): 1.182–4.120, p=0.013], regardless of the onset timing of AF. The rate of new pacemaker insertion at 1 year was also significantly higher in patients with AF than in those with SR (14.0% vs. 5.5%, adjusted HR: 3.137, 95%CI: 1.621–6.071, p=0.001).Among AF patients, substantial number of patients received the combination of multiple antithrombotic agents (77.8%), and the most common combination was that of aspirin and clopidogrel (38.1%). @*Conclusion@#AF was an independent predictor of 1-year mortality and new pacemaker insertion in Korean patients undergoing TAVI.

Lipid-Core Plaque Assessed by Near-Infrared Spectroscopy and Procedure Related Microvascular Injury

BACKGROUND AND OBJECTIVES@#Microvascular damage due to distal embolization during percutaneous coronary intervention (PCI) is an important cause of periprocedural myocardial infarction. We assessed the lipid-core plaque using near-infrared spectroscopy (NIRS) and microvascular dysfunction invasively with the index of microcirculatory resistance (IMR) and evaluated their relationship.@*METHODS@#This study is pilot retrospective observational study. We analyzed 39 patients who performed NIRS before and after PCI, while fractional flow reserve, thermo-dilution coronary flow reserve (CFR) and IMR were measured after PCI. The maximum value of lipid core burden index (LCBI) for any of the 4-mm segments at the culprit lesion (culprit LCBI(4mm)) was calculated at the culprit lesion. We divided the patients into 2 groups using a cutoff of culprit LCBI(4mm) ≥500.@*RESULTS@#Mean pre-PCI LCBI was 333±196 and mean post-PCI IMR was 20±14 U. Post-PCI IMR was higher (15.6±7.3 vs. 42.6±17.6 U, p<0.001) and post-PCI CFR was lower (3.7±2.2 vs. 2.1±1.0, p=0.029) in the high LCBI group. Pre-PCI LCBI was positively correlated with post-PCI IMR (ρ=0.358, p=0.025) and negatively correlated with post-PCI CFR (ρ=−0.494, p=0.001). The incidence of microvascular dysfunction (IMR ≥25 U) was higher in the high LCBI group (9.4% vs. 85.7%, p<0.001). However, there were no significant differences in the incidences of creatine Kinase-MB (9.4% vs. 14.3%, p=0.563) and troponin-I elevation (12.5% vs. 14.3%, p=1.000).@*CONCLUSIONS@#A large lipid-core plaque at the ‘culprit’ lesion is observed higher incidence of post-PCI microvascular dysfunction after PCI. Prospective study with adequate subject numbers will be needed.

Lipid-Core Plaque Assessed by Near-Infrared Spectroscopy and Procedure Related Microvascular Injury

BACKGROUND AND OBJECTIVES: Microvascular damage due to distal embolization during percutaneous coronary intervention (PCI) is an important cause of periprocedural myocardial infarction. We assessed the lipid-core plaque using near-infrared spectroscopy (NIRS) and microvascular dysfunction invasively with the index of microcirculatory resistance (IMR) and evaluated their relationship. METHODS: This study is pilot retrospective observational study. We analyzed 39 patients who performed NIRS before and after PCI, while fractional flow reserve, thermo-dilution coronary flow reserve (CFR) and IMR were measured after PCI. The maximum value of lipid core burden index (LCBI) for any of the 4-mm segments at the culprit lesion (culprit LCBI(4mm)) was calculated at the culprit lesion. We divided the patients into 2 groups using a cutoff of culprit LCBI(4mm) ≥500. RESULTS: Mean pre-PCI LCBI was 333±196 and mean post-PCI IMR was 20±14 U. Post-PCI IMR was higher (15.6±7.3 vs. 42.6±17.6 U, p<0.001) and post-PCI CFR was lower (3.7±2.2 vs. 2.1±1.0, p=0.029) in the high LCBI group. Pre-PCI LCBI was positively correlated with post-PCI IMR (ρ=0.358, p=0.025) and negatively correlated with post-PCI CFR (ρ=−0.494, p=0.001). The incidence of microvascular dysfunction (IMR ≥25 U) was higher in the high LCBI group (9.4% vs. 85.7%, p<0.001). However, there were no significant differences in the incidences of creatine Kinase-MB (9.4% vs. 14.3%, p=0.563) and troponin-I elevation (12.5% vs. 14.3%, p=1.000). CONCLUSIONS: A large lipid-core plaque at the ‘culprit’ lesion is observed higher incidence of post-PCI microvascular dysfunction after PCI. Prospective study with adequate subject numbers will be needed.

Accuracy Analysis of Embletta X100 for the Diagnosis of Obstructive Sleep Apnea and the Assessment of Sleep Structure

BACKGROUND AND OBJECTIVES: To measure the accuracy of Embletta X100, a level 2 portable sleep monitoring device, for diagnosis of obstructive sleep apnea and assessment of sleep structure. MATERIALS AND METHOD: We enrolled 200 consecutive patients who had been referred due to habitual snoring or witnessed apnea during sleep and had undergone standard polysomnography (PSG). We created a simulated situation similar to that of the Embletta X100 using only data from PSG and scored the sleep stage and the apnea-hypopnea index (AHI). Thereafter, the results of PSG and simulated Embletta X100 were compared. RESULTS: Sensitivity, specificity, and positive and negative predictive values of simulated Embletta X100 based on PSG were nearly 100% at three different cutoff values of AHI (5, 15, and 30). Intraclass correlation (ICC) of simulated Embletta X100 based on PSG was also excellent (≥0.9) for most of the sleep-related parameters and respiratory index. However, ICC of sleep stage percent was variable according to sleep stage (>0.9 for N1 and N2, 0.664 for N3, and 0.864 for R). CONCLUSION: Although sleep staging is not very precise, Embletta X100 matches well with PSG overall.

Clinical and Angiographic Outcomes of the First Korean-made Sirolimus-Eluting Coronary Stent with Abluminal Bioresorbable Polymer

BACKGROUND AND OBJECTIVES: This trial evaluated the safety and efficacy of the Genoss drug-eluting coronary stent. METHODS: This study was a prospective, multicenter, randomized trial with a 1:1 ratio of Genoss drug-eluting stent (DES)™ and Promus Element™. Inclusion criteria were the presence of stable angina, unstable angina, or silent ischemia. Angiographic inclusion criteria were de novo coronary stenotic lesion with diameter stenosis >50%, reference vessel diameter of 2.5–4.0 mm, and lesion length ≤40 mm. The primary endpoint was in-stent late lumen loss at 9-month quantitative coronary angiography follow-up. Secondary endpoints were in-segment late lumen loss, binary restenosis rate, death, myocardial infarction (MI), target lesion revascularization (TLR), target vessel revascularization (TVR), and stent thrombosis during 9 months of follow-up. RESULTS: We enrolled 38 patients for the Genoss DES™ group and 39 patients for the Promus Element™ group. In-stent late lumen loss at 9 months was not significantly different between the 2 groups (0.11±0.25 vs. 0.16±0.43 mm, p=0.567). There was no MI or stent thrombosis in either group. The rates of death (2.6% vs. 0%, p=0.494), TLR (2.6% vs. 2.6%, p=1.000), and TVR (7.9% vs. 2.6%, p=0.358) at 9 months were not significantly different. CONCLUSION: This first-in-patient study of the Genoss DES™ stent showed excellent angiographic outcomes for in-stent late lumen loss and major adverse cardiac events over a 9-month follow-up.

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.

Anatomical Discrepancy Between The Coronary Sinus and the Mitral Annulus by Fluoroscopy

BACKGROUND AND OBJECTIVES: Intracardiac electrocardiograms (ECGs) from the coronary sinus (CS) provide important information for identifying a left-sided bypass tract. However, a previous study revealed an anatomical discrepancy between the CS and mitral annulus (MA) in cadaver hearts. The purpose of this study was to evaluate the anatomical relationship between the CS and MA in the living body by using fluoroscopy. SUBJECTS AND METHODS: We analyzed patients who had an ablation for 42 left-sided bypass tracts and one paroxysmal atrial fibrillation. A left atriogram was performed during the ablation by using a pigtail catheter via the transseptal approach. The distances between the CS and MA were measured at 30° right anterior oblique (RAO) and 60° left anterior oblique (LAO) projections at the end of ventricular systole and diastole. RESULTS: The distances between the CS and MA at the RAO projection were 9.74±3.50, 3.86±2.58, and 9.02±6.04 mm during systole and 12.89±5.59, 3.97±3.24, and 10.71±4.12 mm during diastole at the proximal, middle, and distal CS, respectively. The distances between the CS and MA at the LAO projection were 6.84±2.77, 1.80±1.51, and 4.57±3.24 mm during systole and 9.91±3.25, 4.21±3.59, and 7.02±3.12 mm during diastole at the proximal, middle, and distal CS, respectively. CONCLUSION: An anatomical discrepancy was detected between the CS and MA in most cases. Therefore, intracardiac ECGs of the CS cannot exactly localize left-sided bypass tracts.

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.

Three Dimensional Quantitative Coronary Angiography Can Detect Reliably Ischemic Coronary Lesions Based on Fractional Flow Reserve

Conventional coronary angiography (CAG) has limitations in evaluating lesions producing ischemia. Three dimensional quantitative coronary angiography (3D-QCA) shows reconstructed images of CAG using computer based algorithm, the Cardio-op B system (Paieon Medical, Rosh Ha'ayin, Israel). The aim of this study was to evaluate whether 3D-QCA can reliably predict ischemia assessed by myocardial fractional flow reserve (FFR) < 0.80. 3D-QCA images were reconstructed from CAG which also were evaluated with FFR to assess ischemia. Minimal luminal diameter (MLD), percent diameter stenosis (%DS), minimal luminal area (MLA), and percent area stenosis (%AS) were obtained. The results of 3D-QCA and FFR were compared. A total of 266 patients was enrolled for the present study. FFR for all lesions ranged from 0.57 to 1.00 (0.85 +/- 0.09). Measurement of MLD, %DS, MLA, and %AS all were significantly correlated with FFR (r = 0.569, 0609, 0.569, 0.670, respectively, all P < 0.001). In lesions with MLA < 4.0 mm2, %AS of more than 65.5% had a 80% sensitivity and a 83% specificity to predict FFR < 0.80 (area under curve, AUC was 0.878). 3D-QCA can reliably predict coronary lesions producing ischemia and may be used to guide therapeutic approach for coronary artery disease.

Treatment of a Spontaneous Coronary Artery Dissection Involving the Left Main Coronary Artery Using the Culotte Stent Technique / 대한내과학회지

Spontaneous coronary artery dissection (SCAD) is an extremely rare clinical manifestation of ischemic heart disease. A 43-year-old female was admitted to our hospital for non-ST elevation myocardial infarction. She had no cardiac risk factors except smoking. Coronary angiography showed moderate stenosis of the proximal left circumflex artery (LCX) with intraluminal haziness and a spastic appearance from the culprit lesion in the left main coronary artery (LM). Subsequent analysis by intravascular ultrasound (IVUS) revealed a clear dissection flap from the LCX to the LM. Generally, SCAD of the LM or multivessel involvement requires primary surgical management. The present case was treated percutaneously using the culotte stent technique.

A Case of Clozapine-Induced Myocarditis

Clozapine is an atypical antipsychotic agent that is more effective than the typical neuroleptics in the treatment of refractory schizophrenia. Recently, there has been an increased recognition of the association of clozapine with myocarditis and cardiomyopathy. Commonly used diagnostic tests have limited sensitivity in diagnosing this potentially life-threatening complication. Here we report a case of 36-year-old male patient who developed fever, tachycardia, and dyspnea after introduction of clozapine. By clinical evaluation and laboratory test we diagnosed the patient with myocarditis and treated him successfully. To our knowledge this is the first case report of clozapine-induced myocarditis in Korea.

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.

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.

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.

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 Case of Large Left Atrial Myxoma Presenting as Atrial Flutter

Cardiac myxoma is the most common benign cardiac tumor and it presents various clinical symptoms and signs. Although two-thirds of patients have abnormal electrocardiographic findings, atrial flutter or conduction abnormalities are known to be rare. We report on a case of a large left atrial myxoma which was diagnosed by trans-thoracic, trans-esophageal echocardiography, chest computerized tomography, and histological examination. The myxoma was presented as atrial flutter in a 41-year old man who was complaining palpitation and dyspnea on exertion. After surgical excision of the mass, atrial flutter converted to normal sinus rhythm. We report this case with review of literatures on left atrial myxoma associated with arrhythmia.

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.

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.

Correlation between Thrombolysis in Myocardial Infarction, the Myocardial Perfusion Grade and the Myocardial Viability Indices after Primary Percutaneous Coronary Intervention in ST Segment Elevation Myocardial Infarction

BACKGROUND AND OBJECTIVES: The thrombolysis in myocardial infarction (TIMI) myocardial perfusion grade (TMPG) is associated with the long term clinical outcomes. This study compared the TMPG with the myocardial viability as determined by 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), and with improvement of the left ventricular (LV) function on echocardiography. SUBJECTS AND METHODS: We enrolled 44 consecutive patients (37 men: age 56+/-11 years) who underwent primary percutaneous coronary intervention (PCI) for ST segment elevation myocardial infarction (STEMI). We assessed the coronary flow reserve (CFR), the diastolic deceleration time (DDT), the coronary wedge pressure (Pcw) and the coronary wedge pressure/mean aortic pressure (Pcw/Pa). All the patients underwent FDG-PET scans on the 7th day after primary PCI. The patients were divided into 3 groups according to the TMPG (TMPG 0/1: n=18, TMPG 2: n=14, TMPG 3: n=12). RESULTS: There was a significant correlation between the TMPG and the CFR, DDT, Pcw and Pcw/Pa (r=0.367, p=0.017; r=0.587, p<0.001; r=-0.513, p<0.001; r=-0.614, p<0.001, respectively). There was a significant correlation between the TMPG and the % of FDG uptake (r=0.587, p<0.001) and the patients with TMPG 3 had the most favorable % of FDG uptake (TMPG 0/1 vs TMPG 2 vs TMPG 3; 42.0+/-12.3% vs 53.9+/-11.2% vs 59.3+/-13.3%, p=0.001). On echocardiography, the patients with TMPG 3 revealed an improvement of the LV ejection fraction (53.4+/-9.9% vs 60.0+/-7.0%, p=0.004) and the patients with TMPG 2 and TMPG 3 revealed improvement of their regional wall motion abnormality (RWMA) index (1.44+/-0.26 vs 1.24+/-0.18, p=0.022; 1.35+/-0.26 vs 1.15+/-0.18, p=0.018, respectively). CONCLUSION: The angiographically determined TMPG might be clinically useful for the assessment of myocardial viability and it might be a useful predictor for improvement of the LV function in patients suffering with STEMI.

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.