Yoshihiko Atsuchi

Rapid diagnosis of coronary reperfusion by measurement of myoglobin level every 15 min in acute myocardial infarction

OBJECTIVES The purpose of this study was to examine whether coronary reperfusion can be diagnosed rapidly and accurately by myoglobin measurements. BACKGROUND When intravenous thrombolysis is used for acute myocardial infarction, it is important to determine coronary reperfusion rapidly and noninvasively so that further treatment can be initiated. METHODS We determined myoglobin, creatine kinase (CK) and creatine kinase, MB fraction (CK-MB) isoenzyme levels in 63 patients with acute myocardial infarction with total occlusion of the infarct-related artery that was confirmed by coronary angiography. Myoglobin was measured by turbidimetric latex agglutination, which has an assay time of 10 min. We measured myoglobin, CK and CK-MB every 15 min in 45 patients with and 18 patients without reperfusion. The condition of the infarct-related artery was confirmed every 5 to 8 min by coronary angiography. RESULTS The rate of increase in myoglobin, CK, and CK-MB at 15, 30, 45 and 60 min after treatment and reperfusion was significantly higher in the reperfused than in the nonreperfused group. In the reperfused group, the rate of increase in myoglobin was significantly higher than the corresponding rate of increase in CK and CK-MB at 15, 30 and 45 min after reperfusion. When reperfusion was evaluated on the basis of a cutoff level (myoglobin > or = 2.0, CK > or = 1.8, CK-MB > or = 1.5), the predictive accuracy of myoglobin (95%) was significantly higher than that of CK (68%) and CK-MB (73%) at 15 min after reperfusion. CONCLUSIONS Coronary reperfusion can be rapidly and accurately detected by measurement of the plasma myoglobin every 15 min.

Use of the QRS scoring system in the early estimation of myocardial infarct size following reperfusion

While the QRS scoring system has been established as a convenient tool for estimating infarct size in nonreperfused patients during the chronic stage of myocardial infarction, its applicability to reperfused patients in the acute stage has not been established. To investigate whether infarct size could be estimated by the QRS scoring system soon after reperfusion, we evaluated QRS scores obtained serially 6 hours to 1 month after reperfusion, total creatine kinase release, and left ventricular ejection fraction in 126 patients with acute myocardial infarction who underwent successful reperfusion therapy. A significant correlation was observed between the QRS score obtained after 6 hours and that obtained after 1 month (r = .89). The QRS scores obtained after 6 hours and 1 month were significantly correlated with total creatine kinase release (r = -.65 and r = -.75, respectively) and left ventricular ejection fraction (r = .62 and r = .76, respectively). Thus, the QRS scoring system can be used as a simple and economical method for estimation of infarct size soon after reperfusion.

Plasma Level of Triglyceride-rich Lipoprotein Remnants Is Closely Associated with the Activation of Coagulation Factor VII in Patients with Myocardial Infarction

Remnant-like particles, which have been recognized to be atherogenic derivatives of chylomicrons and very low density lipoproteins, can be measured using a new assay kit. The purpose of the present study was to investigate the association of remnant-like particles with the coagulation system that has an important role in the pathogenesis of myocardial infarction. We assayed blood levels of total cholesterol, triglyceride, HDL-cholesterol, apolipoproteins, remnant-like particles-cholesterol, remnant-like particles-triglyceride, fibrinogen, factor VII antigen, activated factor VII, and tissue factor in 111 patients with a history of myocardial infarction and 128 control subjects. In simple regression analysis, plasma levels of remnant-like particles-cholesterol and remnant-like particles-triglyceride showed a significant positive correlation with the levels of activated factor VII (r=0.319, p<0. 001, and r=0.286, p=0.002, respectively) and the activated factor VII/factor VII antigen ratio (r=0.241, p=0.011, and r=0.249, p=0.008, respectively) in patients with myocardial infarction. In contrast, there were no significant differences between remnant-like particles and activated factor VII in control subjects. In stepwise multivariate regression analysis, the significant determinants of activated factor VII were remnant-like particles-cholesterol (10.2%), apolipoproteins A-I (5.1%), and E (7.1%); for the activated factor VII/factor VII antigen ratio, remnant-like particles-triglyceride (6. 2%), age at blood sampling (5.1%), and apolipoprotein A-I (4.0%) in patients with myocardial infarction. However, the significant determinants of activated factor VII and the activated factor VII/factor VII antigen ratio were HDL-cholesterol (9.9% and 9.2%, respectively) in control subjects. It is concluded that remnant-like particles may be a risk factor for myocardial infarction by activating the extrinsic coagulation pathway.

Early detection of coronary reperfusion by rapid assessment of plasma myoglobin

We assayed plasma myoglobin and creatine kinase to elucidate the usefulness of rapid assessment of myoglobin for detecting coronary reperfusion in 31 patients with acute myocardial infarction. Reperfusion was achieved in 20 patients by thrombolytic therapy or angioplasty, and it was not in 11 patients. Blood sampling was performed before and 43 +/- 15 (+/- SD) min after the start of treatment. In the reperfused group, blood samples were obtained before and 26 +/- 10 min after reperfusion. Myoglobin was assayed by a new quantitative test based on latex agglutination turbidimetry which required an assay time of 10 min. After treatment, the rate of increase of plasma myoglobin was significantly higher than that of plasma creatine kinase in the reperfused group (9.7 +/- 9.5 and 2.8 +/- 1.6-fold), but not in the occluded group (1.8 +/- 0.6 and 1.5 +/- 0.3-fold). When a 3.0-fold or greater increase in myoglobin (1.9-fold or greater increase in creatine kinase) was taken as evidence of coronary reperfusion, the sensitivity and specificity were 95% and 100% (70% and 82% in creatine kinase), respectively. In conclusion, using the rate of increase of myoglobin, as measured by latex agglutination turbidimetry, coronary reperfusion can be diagnosed within 1 h after reperfusion.

Myocardial infarct size can be estimated from serial plasma myoglobin measurements within 4 hours of reperfusion.

BackgroundAn early estimation of infarct size is useful for the appropriate early treatment of patients with acute myocardial infarction. We evaluated how early and how accurately infarct size could be estimated from serial plasma myoglobin (Mb) measurements in patients with successful reperfusion Methods and ResultsWe measured plasma Mb and creatine kinase (CK) in 35 patients in whom reperfusion therapy was successfully performed. Blood samples were collected at 15-minute intervals for 2 hours after reperfusion, at 30-minute intervals for the subsequent 2 hours, and at 3-6-hour intervals until 52 hours after reperfusion. Plasma Mb was measured by a newly developed turbidimetric latex agglutination assay. Total Mb and CK release (IMb, ICK) were calculated with a one-compartment model. The mean chord motion in the most hypokinetic 50% of the infarct-related artery territory was calculated from follow-up ventriculograms as an index of the severity of regional hypokinesis. There were significant correlations between 1Mb and ICK (r=0.89), between log 1Mb and the severity of regional hypokinesis (r= -0.85), and between log ICK and the severity of regional hypokinesis (r= -0.74). The time required for the cumulative Mb release curves to reach a plateau was 64±28 minutes. An additional 53±14 minutes was required to calculate the disappearance rate constant of Mb, and 15 minutes was necessary for the assay. Therefore, the total time required for 1Mb to be available was 132±40 minutes, significantly shorter than the time required for ECK, 24.3±9.1 hours (p<0.001). The infarct size could be estimated from the 1Mb in 34 of 35 patients within 4 hours of reperfusion. ConclusionInfarct size can be estimated accurately 4 hours after reperfusion by calculating the YMb in patients with successful reperfusion.

Increased heparin-releasable platelet factor 4 and D dimer in patients one month after the onset of acute myocardial infarction: persistent activation of platelets and the coagulation/fibrinolytic system.

To evaluate the activity of platelets and the coagulation/fibrinolytic system 1 month after the onset of acute myocardial infarction, we measured the plasma levels of molecular markers, i.e. beta-thromboglobulin, platelet factor 4, thrombin-antithrombin III complex and D dimer, in 16 patients with acute myocardial infarction and in 11 normal subjects. Blood was drawn through a catheter placed in the pulmonary artery before heparin injection. The heparin-releasable platelet factor 4 was calculated by subtracting the level before the injection of 5000 U of heparin, from the level 5 min after injection. The plasma beta-thromboglobulin, thrombin-antithrombin III complex and the D dimer levels in the acute phase of myocardial infarction were 134.9 +/- 121.2, 11.2 +/- 7.1 and 164.4 +/- 115.3 ng/ml, respectively. These values were significantly higher than those in the normal subjects. The plasma levels of beta-thromboglobulin and thrombin-antithrombin III complex, 1 month after the onset (36.6 +/- 16.4 and 4.6 +/- 2.3 ng/ml, respectively) were not significantly different from those of the normal subjects. In contrast, D dimer and heparin-releasable platelet factor 4 were 216.9 +/- 176.9 and 80.5 +/- 29.3 ng/ml, respectively, and significantly higher than in the normal subjects. These findings suggest a latent but persistent activation of the platelets and the coagulation/fibrinolytic system 1 month after the onset of acute myocardial infarction.

Simple balloon dilation for drug-eluting in-stent restenosis: An optical coherent tomography analysis☆

BACKGROUND Although drug-eluting stent (DES) has significantly reduced restenosis, the treatment of DES-in-stent restenosis (ISR) remains a challenge with high restenosis rate. METHODS We examined whether morphologic appearance of restenosis tissue by optical coherent tomography (OCT) had an impact on outcomes after balloon angioplasty for DES-ISR. The morphologic appearance of restenosis tissue was qualitatively assessed for tissue structures such as homogeneous, layered, and heterogeneous patterns. RESULTS Using OCT, 50 patients with DES-ISR were divided into 2 groups: 25 lesions with homogeneous or layered patterns (homo/layered group) and 25 lesions with heterogeneous patterns (hetero group). Acute gain was larger in the hetero group (1.33 ± 0.41 mm vs. 1.06 ± 0.32 mm in the homo/layered group, P = 0.03). On intravascular ultrasound analysis, post-procedural percent neointimal area was smaller in the hetero group (27.4 ± 9.2% vs. 34.0 ± 11.2% in the homo/layered group, P = 0.05). Angiographic follow-up was performed in 37 lesions (74%). Follow-up minimal lumen diameter was larger in the hetero group (1.75 ± 0.89 mm vs. 1.01 ± 0.81 mm in the homo/layered group, P = 0.04). Target lesion revascularization rates tended to be lower in the hetero group (20% vs. 43% in the homo/layered group, P = 0.12). CONCLUSIONS Balloon angioplasty was more effective for DES-ISR with heterogeneous tissue appearance than DES-ISR with homogeneous/layered tissue appearance. OCT assessment of DES-ISR morphology may be a useful adjunct in determining clinical strategies. Simple balloon dilatation is a possible treatment strategy for DES-ISR lesions with a heterogeneous appearance on OCT images.

Association of morphologic characteristics on optical coherence tomography and angiographic progression patterns of late restenosis after drug-eluting stent implantation.

OBJECTIVES To gain insight into the pathophysiology of late drug-eluting stent (DES) restenosis. BACKGROUND Restenosis of DES has a different time course from that of bare metal stents. METHODS Patients who underwent follow-up coronary angiography (CAG) twice (six to nine months and 18 to 24 months) after DES implantation were examined using optical coherence tomography (OCT). All lesions with target lesion revascularization at first follow-up were excluded. Late catch-up was defined as lesions that progressed from less than 50% diameter stenosis (DS) at the first CAG to more than 50% DS at the second CAG. Lesions with the late catch-up were further divided into two groups; lesions with jump-up (less than 25% DS at the first CAG) and lesions with gradual progression (25-50% DS at the first CAG). RESULTS Of the 25 patients who had late ISR, 23 patients (10 jump-up/13 gradual progression) were examined with OCT at late follow-up and enrolled in this study. In the qualitative OCT assessment, each ratio of homogeneous, layered, heterogeneous with or without attenuation tissue morphologies were in jump-up group, and gradual progression group were 0% and 15%, 0% and 23%, and 60% and 8%, and 40% and 54%, respectively. All of jump-up group showed heterogeneous restenotic tissue, while 62% of gradual progression group showed heterogeneous restenotic tissue (P = .04). CONCLUSIONS These findings suggest different pathophysiology of the late catch-up after DES implantation between the jump-up and gradual progression groups.

Coronary stent intussusception after intravascular ultrasound catheter removal: optical coherence tomography finding.

An 83-year-old man with hypertension and hyperlipidemia presented with angina chest pain. Diagnostic coronary angiography revealed a severe stenosis at the distal segment of the left circumflex artery ([Fig. 1][1]). After pre-dilation, a XIENCE V stent (Abbott Vascular, Santa Clara, California) was

Late regression of Cypher in-stent restenosis.

We encountered a case of late regression after sirolimus-eluting stent restenosis. We report this case with intravascular ultrasound imaging demonstrating an intraluminal echolucent tissue, which looks like a black hole.