Comprehensive validation of early diagnostic algorithms for myocardial infarction in the emergency department.

OBJECTIVE: To comprehensively evaluate diagnostic algorithms for myocardial infarction using a high-sensitivity cardiac troponin I (hs-cTnI) assay. PATIENTS AND METHODS: We prospectively enrolled patients with suspected myocardial infarction without ST-segment elevation from nine emergency departments in Japan. The diagnostic algorithms evaluated: (i) based on hs-cTnI alone, such as the European Society of Cardiology (ESC) 0/1-h or 0/2-h and High-STEACS pathways; or (ii) used medical history and physical findings, such as the ADAPT, EDACS, HEART, and GRACE pathways. We evaluated the negative predictive value (NPV), sensitivity as safety measures, and proportion of patients classified as low or high-risk as an efficiency measure for a primary outcome of type 1 myocardial infarction or cardiac death within 30 days. RESULTS: We included 437 patients, and the hs-cTnI was collected at 0 and 1 hours in 407 patients and at 0 and 2 hours in 394. The primary outcome occurred in 8.1% (33/407) and 6.9% (27/394) of patients, respectively. All the algorithms classified low-risk patients without missing those with the primary outcome, except for the GRACE pathway. The hs-cTnI-based algorithms classified more patients as low-risk: the ESC 0/1-h 45.7%; the ESC 0/2-h 50.5%; the High-STEACS pathway 68.5%, than those using history and physical findings (15-30%). The High-STEACS pathway ruled out more patients (20.5%) by hs-cTnI measurement at 0 hours than the ESC 0/1-h and 0/2-h algorithms (7.4%). CONCLUSIONS: The hs-cTnI algorithms, especially the High-STEACS pathway, had excellent safety performance for the early diagnosis of myocardial infarction and offered the greatest improvement in efficiency.

Effects of eplerenone on the activation of matrix metalloproteinase-2 stimulated by high glucose and interleukin-1ß in human cardiac fibroblasts.

The aim of this study was to determine the influence of high glucose (HG) and interleukin (IL)-1ß on human cardiac fibroblast (HCF) functions, and to evaluate the effects of eplerenone in these responses. HCFs were cultured in normal or HG media in the absence or presence of IL-1ß and/or eplerenone. We assessed matrix metalloproteinase-2 (MMP-2) activity in the supernatant by in-gel zymography, and determined mRNA expression levels of MMP-2 and tissue inhibitor of metalloproteinase-2 (TIMP-2) by reverse transcription-polymerase chain reaction. Equimolar D-mannitol was used as an osmotic control. HG stimulated MMP-2 activity and promoted MMP-2 mRNA synthesis. Increased effects were also observed in equimolar D-mannitol treatments, but these effects were weaker compared to those of glucose. The combination of HG and IL-1ß resulted in a 2-fold increase in MMP-2 activity and mRNA expression compared with HG or IL-1ß alone. Increases in HG- or IL-1ß-induced MMP-2 activity and mRNA expression were blocked by eplerenone. Neither HG nor IL-1ß affected TIMP-2 mRNA expression. HG increased MMP-2 activity by regulation of MMP- 2 mRNA expression in HCFs through osmotic and non-osmotic pathways. Synergistic effects of IL-1ß added to HG media on MMP-2 activity and mRNA expression were observed in HCFs. Eplerenone normalized the effect of MMP-2 activity and HG- or IL-1ß-induced expression in HCFs.

Clinical significance of reverse redistribution on resting thallium-201 imaging in patients with vasospastic angina.

To evaluate the clinical significance of reverse redistribution (RR) of resting 201Tl single photon emission computed tomography (SPECT) in patients with vasospastic angina (VSA), we performed left ventriculography, coronary angiography and resting 201Tl-SPECT in 22 patients with VSA. Left ventriculography showed abnormal wall motion in 17 of 22 patients (77%) and 37 of 154 segments. Thirty-one of these 37 segments (84%) were within the area perfused by coronary arteries showing acetylcholine-induced vasospasm. On 201Tl images, abnormal findings were observed in 11 of 22 patients (50%), and among them, 7 patients (32%) had RR. Seven of 37 segments (19%) having abnormal regional wall motion had RR of 201TI, and in 6 of these 7 segments (86%), accumulation of 123I-BMIPP was found to be reduced. We conclude that repetitive brief myocardial ischemia may cause myocardial injuries in patients with VSA, and that the presence of RR of 201Tl indicates the presence of myocardial injury in these patients.

Nitric oxide synthase activity in peripheral polymorphonuclear leukocytes in patients with chronic congestive heart failure.

Increased activity of inducible nitric oxide synthase (NOS) has been found in cardiac tissue and in skeletal muscle from patients with chronic congestive heart failure (CHF). There have been few reports investigating NOS activity in other organs or in peripheral blood cells from patients with chronic CHF. To examine whether NOS activities in peripheral polymorphonuclear leukocytes (PML) are increased in patients with chronic CHF and to determine whether a correlation exists between disease severity and NOS activity in PML of patients with chronic CHF, we assessed the levels of NOS activity in PML by measuring the capacity of isolated PML to convert 3H-L-arginine to 3H-L-citrullin in 70 Japanese patients with chronic CHF and in 24 age-matched healthy volunteers. The levels of NOS activity in PML were significantly greater in patients with chronic CHF than in healthy volunteers (18.0 +/- 0.6% vs 11.5 +/- 0.3%, p <0.01). NOS activity in PML was increased with the severity of New York Heart Association functional class. Among the various neurohumonal factors, the plasma levels of interleukin-6, atrial natriuretic peptide, and norepinephrine showed independent and significant positive relations with levels of NOS activity in PML. Thus, we demonstrated that NOS activity in PML was elevated in patients with chronic CHF in relation to the severity of heart failure, circulating proinflammatory cytokines, and neurohormonal factors.

The role of protein-tyrosine phosphorylation and gelatinase production in the migration and proliferation of smooth muscle cells.

BACKGROUND: It has been reported that matrix metalloproteinase (MMP) was expressed in coronary arterial atherosclerotic lesions. However, not much is known about the relationship between the production of MMP and the progression of atherosclerosis. PURPOSE AND METHOD: To demonstrate the association between the protein-tyrosine phosphorylation (PTP) and the activation of extracellular MMP in the proliferation and migration of vascular smooth muscle cells (VSMCs), the effect of platelet-derived growth factor (PDGF) and vanadate (an inhibitor of protein-tyrosine phosphatase and an activator of certain protein-tyrosine kinases) on mitogenesis ([3H]thymidine incorporation after 24 hours), migration, PTP (Western blot analysis using anti-phosphotyrosine antibodies), and production of MMP (gelatin zymography) was examined in cultured VSMCs. RESULTS: Both vanadate (1-5 micromol/l) and PDGF (1-10 ng/ml) caused a dose-dependent increase in thymidine incorporation and migration and produced 72-kDa type IV gelatinase (MMP-2) in VSMCs. The combination of vanadate and PDGF resulted in a dose-dependent synergistic effect on thymidine incorporation and MMP-2 production. Western blot analysis revealed that PDGF caused an increase in PTP, extracellular signal-regulated kinases (ERK1, ERK2) and PDGF receptor in VSMCs. Vanadate given together with PDGF induced a marked increase in the intensity of tyrosine phosphorylation in these proteins. Tyrosine kinase inhibitors (genistein and herbimycin A) and a synthetic inhibitor of MMP (1,10-phenanthroline) and an anti-MMP-2 neutralizing antibody inhibited the mitogenic effect induced by vanadate and/or PDGF. CONCLUSIONS: The data suggest that the proliferation and migration of cultured VSMCs was closely related to the stimulation of MMP-2 production that was induced through activation of PTK.

[Echocardiographic and hematological variables as a risk factor for stroke in chronic nonvalvular atrial fibrillation].

The relationship between echocardiographic variables and the incidence of ischemic stroke in patients with atrial fibrillation was investigated by transthoracic and transesophageal echocardiography in 67 patients with chronic nonvalvular atrial fibrillation. Hematologic variables were also measured simultaneously, including plasma levels of D-dimer and thrombin-antithrombin III complex in these patients. There was a prior history of ischemic stroke in 13 patients (stroke group), but not in the other 54 patients (nonstroke group). There were no significant differences in age, sex, left ventricular ejection fraction, left ventricular end-diastolic diameter, left atrial diameter or hematologic parameters between the groups. The left atrial appendage emptying flow velocity was lower in the stroke group than in the nonstroke group (21 +/- 5 vs 32 +/- 3 cm/sec, p < 0.05), and the incidence of left atrial spontaneous echo contrast was significantly higher in the stroke group than in the nonstroke group (69% vs 26%, p < 0.01). There was no significant difference in the incidence of left atrial thrombi between the groups (23% vs 12%). These findings suggest that transesophageal echocardiographic variables are correlated with the risk of ischemic stroke in patients with chronic nonvalvular atrial fibrillation.

Recovery of perfusion, glucose utilization and fatty acid utilization in stunned myocardium.

We describe the clinical features and results of cardiac catheterization, PET ([13N]ammonia, 18F-fluorodeoxyglucose (FDG)) and SPECT [123I-labeled 15-(p-iodophenyl)-3-R,S-methylpentadecanoic acid (BMIPP)], in a patient with acute myocardial infarction successfully treated with intracoronary thrombolytic therapy. We compared the clinical and electrocardiographic changes with the myocardial glucose and fatty acid metabolism in stunned myocardium over a period of several months. The patient we studied illustrates the features of stunned myocardium. In the subacute phase, there was a concordant depression of myocardial [13N]ammonia and FDG uptake, and the metabolic abnormalities persisted even after regional wall motion at rest had returned to normal. The electrocardiographic recovery of deep negative T waves appeared to be related to the metabolic recovery in regions of stunned myocardium in this patient.

Assessment of left ventricular myocardial perfusion and diastolic function during acetylcholine-induced diffuse coronary vasoconstriction by Doppler echocardiography and thallium-201 scintigraphy.

BACKGROUND: We investigated whether diffuse coronary vasoconstriction induced by acetylcholine caused myocardial ischemia. METHODS: We studied 30 patients (40 coronary arteries) with spontaneous chest pain or equivocal studies on treadmill exercise testing and no significant coronary stenosis or previous myocardial infarction. During the acetylcholine provocation test, Doppler echocardiography was performed, and thallium-201 was injected intravenously for scintigraphy. We used Doppler echocardiography to measure the ratio of early-to-late peak mitral flow (E:A ratio). RESULTS: When acetylcholine was injected, the coronary arteries showed three different responses. Diffuse coronary vasoconstriction without chest pain or ischemic changes on the ECG was induced in 18 (45%) arteries and the E:A ratio decreased from 0.83 +/- 0.13 to 0.77 +/- 0.13 (P = 0.031). In 17 vessels (control arteries), the E:A ratio did not change significantly (from 0.88 +/- 0.15 to 0.88 +/- 0.18; P = 0.95). In five arteries, focal spasm was induced and the E:A ratio decreased from 0.83 +/- 0.18 to 0.66 +/- 0.13 (P = 0.043). Transient defects on thallium-201 scintigraphy were observed in the territory of eight (80%) arteries with diffuse vasoconstriction and in one (20%) control artery (P = 0.047). CONCLUSIONS: Diffuse coronary vasoconstriction induced by intracoronary acetylcholine can decrease the regional myocardial blood flow (as shown by thallium-201 scintigraphy) and can cause global left ventricular diastolic dysfunction (as shown by the results of Doppler echocardiography).

[Induction of coronary artery spasm by combined cold pressor and hyperventilation test in patients with variant angina].

To examine whether or not a combination of nonpharmacologic provocative tests potentiated the occurrence of coronary spasm, the cold pressor test combined with hyperventilation was studied in 22 consecutive patients with variant angina admitted to our hospital. After a 12-lead electrocardiogram and blood pressure were recorded, the patient was asked to hyperventilate vigorously at a rate of 30 respirations per min for 6 min under continuous electrocardiographic monitoring. Immediately after hyperventilation, the cold pressor test was performed with the patient's right hand submerged in ice water for 2 min. In some patients who showed a positive response to the combined test, a hyperventilation and cold pressor test was performed on another day. Positive response (ST segment elevation > or = 0.1 mV) to the combination test was seen in 18 of 22 patients (82%). Positive response to the hyperventilation test was seen in seven of 11 patients (64%). The response to cold pressor test was all negative in seven patients. The onset of electrocardiographic changes by the combined test occurred an average of 120 sec (30-240 sec) after the end of hyperventilation, whereas the onset by hyperventilation test occurred an average of 210 sec later (60-370 sec). These results suggest the combination of the cold pressor test and hyperventilation test potentiated the occurrence of coronary spasm. The combined cold pressor and hyperventilation test is a powerful and useful nonpharmacologic provocative test for coronary artery spasm in patients with variant angina.