Effects of coronary artery reperfusion on myocardial infarct size calculated from creatine kinase

Shorter door-to-balloon time, better long-term clinical outcomes in ST-segment elevation myocardial infarction patients: J-MINUET substudy

BACKGROUND

The impact of shorter door-to-balloon (DTB time on long-term outcomes in ST-segment elevation myocardial infarction (STEMI treated with primary percutaneous coronary intervention (PPCI has not been fully elucidated.

METHODS

We investigated 3283 consecutive patients with acute myocardial infarction selected from a prospective, nationwide, multicenter registry (J-MINUET database comprising 28 institutions in Japan between July 2012 and March 2014. Among the study population, we analyzed 1639 STEMI patients who had PPCI within 12 h of onset. Patients were stratified into four groups (DTB time < 45 min, 45-60 min, 61-90 min, >90 min. The primary endpoint was a composite of all-cause death, non-fatal MI, non-fatal stroke, cardiac failure, and urgent revascularization for unstable angina up to 3 years. We performed landmark analysis for incidence of the primary endpoint from 31 days to 3 years among the four groups.

RESULTS

The primary endpoint rate from 31 days to 3 years increased significantly and time-dependently with DTB time (10.2 % vs. 15.3 % vs. 16.2 % vs. 19.3 %, respectively; log-rank p = 0.0129. Higher logarithm-transformed DTB time was associated with greater risk of a primary endpoint from 31 days to 3 years, and the increased number of adverse long-term clinical outcomes persisted even after adjusting for other independent variables.

CONCLUSION

Shorter DTB time was associated with better long-term clinical outcomes in STEMI patients treated with PPCI in contemporary clinical practice. Further efforts to shorten DTB time are recommended to improve long-term clinical outcomes in STEMI patients.

TRIAL REGISTRATION

UMIN Unique trial Number: UMIN000010037.

Effect of ischemic postconditioning during primary percutaneous coronary intervention for patients with ST-segment elevation myocardial infarction: A single-center cross-sectional study

Background and Objective

Reperfusion therapy for acute myocardial infarction has been shown to reduce mortality, yet it may also have deleterious effects, including myocardial necrosis and no-reflow. Postconditioning is known measure for cardioprotection from reperfusion injury in animal model. Postconditioning is known measure for cardioprotection from reperfusion injury in animal model and human studies have shown inconsistent results.

Materials and Methods

From February 2013 through October 2014, at Institute of Postgraduate Medical Education and Research, Kolkata Cardiology department, we randomized 43 patients with acute ST-segment elevation myocardial infarction (STEMI) who were undergoing conventional primary percutaneous coronary intervention (PCI) (22 patients) and PCI with postconditioning by repeated transient balloon occlusion after establishment of flow (21 patients). Total creatine kinase-muscle/brain (CPK-MB) released within 72 h was compared as a surrogate marker of infarct size. Myocardial blush grade between two groups was also compared.

Results

The area under curve of serum creatine kinase (CK) release during the 1^st 72 h of reperfusion was significantly reduced (P = 0.0347) in the postconditioned group compared with the control group, averaging 9632 IU in postconditioned compared with 13493 IU in control group which represented 29% of reduction of infarct size. The peak of CPK-MB release was markedly lower in the postconditioned (290 ± 16.24 IU/L) than in the control (414.2 ± 51.34 IU/L) group (P ≤ 0.0001). Blush grading was also significantly improved in postconditioned group (P = 0.005). Mean ST-segment deviation at 48 h between cases and control groups was 0.87 ± 0.68 and 1.4 ± 0.94, respectively (P = 0.08).

Conclusion

In patients with STEMI, postconditioning significantly improves blush grading and enzymatic infarct size reduction with a trend toward significant reduction of mean ST-segment deviation.

Kinetic modelling of myocardial necrosis biomarkers offers an easier, reliable and more acceptable assessment of infarct size

Infarct size is a major prognostic factor in ST-segment elevation myocardial infarction (STEMI). It is often assessed using repeated blood sampling and the estimation of biomarker area under the concentration versus time curve (AUC) in translational research. We aimed at developing limited sampling strategies (LSS) to accurately estimate biomarker AUC using only a limited number of blood samples in STEMI patients. This retrospective study was carried out on pooled data from five clinical trials of STEMI patients (TIMI blood flow 0/1) studies where repeated blood samples were collected within 72 h after admission to assess creatine kinase (CK), cardiac troponin I (cTnI) and muscle-brain CK (CK-MB). Biomarker kinetics was assessed using previously described biomarker kinetic models. A number of LSS models including combinations of 1 to 3 samples were developed to identify sampling times leading to the best estimation of AUC. Patients were randomly assigned to either learning (2/3) or validation (1/3) subsets. Descriptive and predictive performances of LSS models were compared using learning and validation subsets, respectively. An external validation cohort was used to validate the model and its applicability to different cTnI assays, including high-sensitive (hs) cTnI. 132 patients had full CK and cTnI dataset, 49 patients had CK-MB. For each biomarker, 180 LSS models were tested. Best LSS models were obtained for the following sampling times: T4-16 for CK, T8-T20 for cTnI and T8-T16 for CK-MB for 2-sample LSS; and T4-T16-T24 for CK, T4-T12-T20 for cTnI and T8-T16-T20 for CK-MB for 3-sample LSS. External validation was achieved on 103 anterior STEMI patients (TIMI flow 0/1), and the cTnI model applicability to recommended hs cTnI confirmed. Biomarker kinetics can be assessed with a limited number of samples using kinetic modelling. This opens the way for substantial simplification of future cardioprotection studies, more acceptable for the patients.

Beneficial effect of polaprezinc on cardiac function post-myocardial infarction: A prospective and randomized clinical trial

BACKGROUND

Polaprezinc is clinically used for the treatment of gastric ulcers. It induces the mobilization of mesenchymal stem cells and the mRNA expression of insulin-like growth factor-1 in vascular endothelial cells in order to protect injured gastric tissue or skin.

METHODS

The current study population included 50 patients with primary acute myocardial infarction (AMI). After percutaneous coronary intervention, the subjects were randomly divided into 2 groups, namely, the nonpolaprezinc and polaprezinc groups. Peripheral blood and urinary samples were collected in a specific time to analyze zinc concentration, cardiac enzymes, and the levels of the inflammation marker interleukin-6. To evaluate the cardiac function, echocardiography was performed upon admission to the hospital and at 9 months post-AMI.

RESULTS

The urine and blood zinc levels of the polaprezinc group were higher compared with those of the non-polaprezinc group at 8 days after percutaneous coronary intervention. The mean interleukin-6/maximal creatine phosphokinase level was significantly reduced in the polaprezinc group (0.024 [0.003-0.066] vs. 0.076 [0.015-0.212], respectively; P = .045). In addition, echocardiography revealed that the ejection fraction of the nonpolaprezinc group was not significantly increased between day 3 and 9 months post-AMI (53 [49-60.8] vs. 59.5 [52-69.3], respectively; P = .015). However, a significant increase was detected in the ejection fraction of the polaprezinc group at the 2 time points (54 [51-57] vs. 62 [55-71], respectively; P < .01).

CONCLUSIONS

The results of the present study suggest that polaprezinc has an anti-inflammatory effect and improves cardiac function after AMI.

Mortality impact of post-discharge myocardial infarction size after percutaneous coronary intervention: a patient-level pooled analysis from the 4 large-scale Japanese studies

It is unknown whether there is a threshold of creatine kinase (CK) or CK-MB affecting the subsequent mortality for post-discharge myocardial infarction (PDMI) after percutaneous coronary intervention. Current study sought to evaluate the impact of PDMI. The study population included 30,051 patients with successful coronary stenting and discharged alive in the pooled patient-level database of 4 Japanese studies (j-Cypher registry, CREDO-Kyoto PCI/CABG registry cohort-2, RESET, and NEXT). During 4.4 ± 1.4 year follow-up, 915 patients experienced PDMI (cumulative 5-year incidence of 3.6%). Among 466 patients with available peak CK ratio (peak CK/upper limit of normal), peak CK ratio (< 3) was present in 21% of patients, while peak CK ratios (≥ 3 and < 5), (≥ 5 and < 10), (≥ 10 and < 30), and (≥ 30) were present in 17, 25, 30, and 7.3% of patients, respectively. The excess mortality risk of patients with relative to those without PDMI for subsequent mortality was significant (adjusted HR 5.12, 95% CI 4.52-5.80, P < 0.001) by the Cox model with PDMI incorporated as the time-updated covariate. However, the mortality risk of patients in the smallest peak CK ratio category (< 3) was insignificant (HR 0.85, 95% CI 0.43-1.71, P = 0.65). In conclusion, despite significant overall mortality risk of PDMI, the mortality risk of small PDMI was similar to that of no PDMI, suggesting the presence of some threshold about infarct size influencing mortality.Trial registrations The Randomized Evaluation of Sirolimus-Eluting Versus Everolimus-Eluting Stent Trial (RESET); NCT01035450 and NOBORI Biolimus-Eluting Versus XIENCE/PROMUS Everolimus-Eluting Stent Trial (NEXT); NCT01303640. J-Cypher and CREDO-Kyoto PCI/CABG registry cohort 2 were not registered into clinical trial database.

Revisiting myocardial necrosis biomarkers: assessment of the effect of conditioning therapies on infarct size by kinetic modelling

Infarct size is a major predictor of subsequent cardiovascular events following ST-segment elevation myocardial infarction (STEMI) and is frequently used in clinical trials focused on cardioprotection. Approximately assessed through serial blood sampling, it can be accurately measured by imaging techniques, e.g. cardiac magnetic resonance imaging, which is the actual gold standard for infarct size determination but with limited availability in daily practice. We developed a mathematical biomarker kinetic model based on pharmacokinetic compartment models to easily and accurately estimate infarct size using individual data from five clinical trials evaluating the impact of conditioning therapies in STEMI between 2005 and 2013. Serial blood sampling was available in all studies with data regarding creatine kinase (CK), CK specific of cardiomyocytes (CK-MB) and cardiac troponin I. Our model allowed an accurate estimation of biomarker release as a surrogate marker of infarct size and a powerful assessment of conditioning treatments. This biomarker kinetic modelling approach identified CK-MB as the most accurate biomarker in determining infarct size and supports the development of limited sampling strategies that estimate total biomarker amount released with a lower number of samples. It will certainly be a useful add-on to future studies in the field of STEMI and cardioprotection.

Left ventricular ejection fraction and mortality in patients with ST-elevation myocardial infarction and bundle branch block

BACKGROUND

The aim of our study is to assess the effect of bundle branch block (BBB) on mortality and left ventricular ejection fraction (LVEF) in ST-elevation myocardial infarction (STEMI) patients treated in the current era of percutaneous reperfusion therapy.

PATIENTS AND METHODS

In this retrospective cohort study, a total of 1123 STEMI patients treated in the University Medical Center Groningen from January 2011 until May 2013 were included. The follow-up duration was 2-4 years. Transthoracic echocardiography was performed within 2 weeks after STEMI.

RESULTS

In total, 23 (2.0%) patients presented with left BBB and 49 (4.4%) patients presented with right BBB. Two-year mortality after STEMI was 25.0% (n=18) in patients with BBB and 9.2% (n=97, P<0.001) in patients without BBB. Patients with BBB had more frequently a severely reduced LVEF (<30%) [20.0% (n=6) compared with 4.2% (n=21), P=0.002] and less frequently a normal LVEF [16.7% (n=5) compared with 35.7% (n=179), P=0.046]. After multivariable analysis, BBB did not remain an independent predictor of mortality, but was an independent predictor of reduced LVEF.

CONCLUSION

The presence of a BBB was an independent predictor of a reduced LVEF. However, we found no effect of BBB on 2-year mortality in the current era of percutaneous reperfusion therapy.

Cardiac troponin elevation pattern in patients undergoing a primary percutaneous coronary intervention for ST-segment elevation myocardial infarction: characterization and relationship with cardiovascular events during hospitalization

HYPOTHESIS

We aimed to describe the kinetics and associated prognostic implications of the cardiac troponin release curve after a primary percutaneous coronary intervention (PPCI) in patients presenting with ST-segment elevation myocardial infarction (STEMI).

PATIENTS AND METHODS

We prospectively determined, in a prespecified timely manner, serial cardiac troponin I levels and obtained clinical, ECG, and echocardiographic data from 175 consecutive patients hospitalized with STEMI who underwent PPCI. The median peak troponin levels and time until troponin peaking were determined.

RESULTS

The troponin elevation curve following PPCI was single peaked, with a median value measuring 715 times the upper normal limit and a median peaking time of 8 h. Later-peaking troponin levels were associated with a TIMI flow grade of 0/1 at the initiation of angiography and with lack of at least 70% regression in the ST-elevation on the first post-PPCI ECG. Higher peak values were similarly associated with these two parameters as well as with a lower blush score and with distal embolization during PPCI. Both higher peak values and later peaking of troponin were associated independently with higher occurrence of the combined adverse cardiovascular event outcomes consisting of death, congestive heart failure, and recurrent infarction.

CONCLUSION

The cardiac troponin elevation curve following PPCI for STEMI shows a single peak and is affected by the adequacy of myocardial reperfusion. This method can serve as a simple surrogate for risk stratification of patients with STEMI who undergo PPCI.

Epitope mapping and targeted quantitation of the cardiac biomarker troponin by SID-MRM mass spectrometry

The absolute quantitation of the targeted protein using MS provides a promising method to evaluate/verify biomarkers used in clinical diagnostics. In this study, a cardiac biomarker, troponin I (TnI), was used as a model protein for method development. The epitope peptide of TnI was characterized by epitope excision followed with LC/MS/MS method and acted as the surrogate peptide for the targeted protein quantitation. The MRM-based MS assay using a stable internal standard that improved the selectivity, specificity, and sensitivity of the protein quantitation. Also, plasma albumin depletion and affinity enrichment of TnI by anti-TnI mAb-coated microparticles reduced the sample complexity, enhanced the dynamic range, and further improved the detecting sensitivity of the targeted protein in the biological matrix. Therefore, quantitation of TnI, a low abundant protein in human plasma, has demonstrated the applicability of the targeted protein quantitation strategy through its epitope peptide determined by epitope mapping method.

The effect of experimental streptococcus infection in myocarditis on some biochemical and inflammatory markers in albino rats

BACKGROUND

Myocarditis is an uncommon disease that presents with a wide range of symptoms in children and adults. It is histologically characterized by varying degrees of myocardialnecrosis, edema and cellular infiltration myocardial inflammation is a nonspecificresponse to many triggers such as bacterial infection, cardio toxic agents, ormechanical injury.

OBJECTIVE

This study was carried out to investigate the experimental Streptococcus faecalis induction of myocarditis and its effect on some blood parameters, inflammatory markers and histopathological changes in male albino rats.

METHODS

Rats were infected by intraperitoneal injection of 10 8 CFU/ml of Streptococcus faecalis and sacrificed after one, two and seven days post infection. Biochemical analyses of blood were carried out to investigate the serum biomarkers of inflammation, liver function tests, cardiac enzymes & kidney function tests.

RESULTS

All biochemical analyses showed statistically significant increase in the measured parameters due to bacterial infections except for blood urea which appear to be normal. A significant positive correlation was observed between lactate dehydrogenase enzyme (LDH) with creatinine (r =0.778, P<0.01). In the 7 days group, there were significant positive correlations between aspartate aminotransferase (AST) and alanine aminotransferase (ALT) (r=0.675, P<0.05), erythrocyte sedimentation rate (ESR) with Urea (r=0.659, P<0.05) and alkaline phosphatase (ALP) with C-reactive protein (CRP) (r=0.765, p<0.01).

CONCLUSION

Many of these biomarkers will provide important new insights into pathophysiology and aid in the diagnosis and management of cardiovascular patients.

Peak and fixed-time high-sensitive troponin for prediction of infarct size, impaired left ventricular function, and adverse outcomes in patients with first ST-segment elevation myocardial infarction receiving percutaneous coronary intervention

The clinical use of advanced imaging modalities for early determination of infarct size and prognosis is limited. As a specific indicator of myocardial necrosis, cardiac troponin T (cTnT) can be used as a surrogate measure for this purpose. The present study sought to investigate the use of peak and serial 6-hour fixed-time high-sensitive (hs) cTnT for estimation of infarct size, left ventricular (LV) function, and prognosis in consecutive patients with ST-segment elevation myocardial infarction. The infarct size was expressed as the 48-hour cumulative creatine kinase release. LV function at 3 months was assessed using the echocardiographic wall motion score index and LV ejection fraction using radionuclide ventriculography. Adverse outcomes, comprising all-cause death, implantable cardioverter-defibrillator implantation, or hospitalization for heart failure, were recorded at 1 year of follow-up. In 188 patients, the peak and all fixed-time values correlated significantly with the 48-hour cumulative creatine kinase release, wall motion score index, and LV ejection fraction. The hs-cTnT value at 24 hours demonstrated the greatest correlation (r = 0.86, r = 0.47, and r = -0.59, respectively; p <0.001 for all). In the multivariate regression models adjusted for the clinical parameters, almost all were independently associated with the 48-hour cumulative creatine kinase release, wall motion score index, and LV ejection fraction, with the hs-cTnT value at 24 hours having the largest effect. Moreover, all cTnT values independently predicted adverse outcomes, again, with the hs-cTnT value at 24 hours showing the largest influence (hazard ratio 3.77, 95% confidence interval 2.12 to 6.73, p <0.001). In conclusion, not only peak, but all fixed-time hs-cTnT values were associated with infarct size, LV function at 3 months, and adverse outcomes 1 year after ST-segment elevation myocardial infarction. The value 24 hours after the onset of symptoms had the closest associations with all outcomes. Therefore, serial sampling for a peak value might be redundant.

Predictive value of cardiac troponin-I compared to creatine kinase-myocardial band for the assessment of infarct size as measured by cardiac magnetic resonance

BACKGROUND

The estimation of infarct size by biochemical myocardial necrosis markers is used in current clinical practice, rather than the more expensive and not always available imaging techniques. However, for this purpose, the peak value of serum biomarkers can overestimate the necrotic area, especially after reperfusion.

OBJECTIVE

We investigated whether late release cardiac troponin I (cTnI) values could predict more precisely infarct volume measured by delayed-enhancement cardiac magnetic resonance (DE-CMR) in patients with acute myocardial infarction [ST-elevation myocardial infarction (STEMI) and non-STEMI (NSTEMI)] independently of reperfusion (spontaneous and provoked).

METHODS

Sixty patients with a first acute myocardial infarction (55 STEMI and five NSTEMI) and normal function were enrolled. Among STEMI patients, 52 underwent reperfusion. cTnI and creatine kinase-myocardial band were assessed at admission and at 6, 12, 24, 48, 72 and 96 h (+/-1 h) from symptom onset. DE-CMR (Siemens Avanto 1.5T) was performed before discharge (4 +/- 2 days). Infarct size was determined by manual delineation of the areas of delayed enhancement. Infarct volume was calculated as the sum of each slice of infarct size area multiplied by thickness.

RESULTS

Peak cTnI was 55 +/- 59 ng/ml (range 0.3-347). The area under the curve of cTnI was 1916 +/- 2224 ng/ml. The volume of infarcted myocardium assessed by DE-CMR was 27 +/- 25 ml (range 0-134). The single value of cTnI at 72 h after symptom onset provided the most accurate estimation of predischarge infarct volume (r = 0.84, 95% confidence interval 0.75-0.91) and was significantly more accurate than creatine kinase-myocardial band value assessed at any time during the same period (r = 0.42, 95% confidence interval 0.19-0.62; P < 0.002).

CONCLUSION

In patients with a first acute myocardial infarction, cTnI value assessed at 72 h from symptom onset shows the best correlation with predischarge infarct volume as assessed by DE-CMR and is superior to cTnI and creatine kinase-myocardial band peak and total values.

Assessment of coronary artery flow velocity pattern as a long-term predictor of left ventricular function and cardiac events after percutaneous coronary intervention in anterior acute myocardial infarction

BACKGROUND

Coronary flow velocity (CFV) can be used to assess short-term left ventricular function recovery and the clinical prognosis of patients with acute myocardial infarction (AMI). We evaluated CFV as a predictor of long-term left ventricular function recovery and cardiac events in patients with anterior wall AMI.

METHODS AND RESULTS

CFV pattern of the distal left anterior descending (LAD), wall motion score index (WMSI) and left ventricular ejection fraction (LVEF) were recorded at the points of time within 24 hours, 3 days, 6 months, and 3 years after percutaneous coronary intervention (PCI) in 50 consecutive patients with anterior wall AMI. The clinical data were collected. Patients were divided into two groups based on diastolic deceleration time (DDT) 3 days after PCI. Compared with 3 days, LVEF and WMSI in group A (DDT>600 ms, n=20) improved in 6 months and 3 years (p<0.01), but they were unchanged in group B (DDT< or =600 ms, n=30). The incidence of cardiac events was higher in group B than in group A during 6 months (p<0.01).With a 3-year follow up, the incidence of chronic heart failure was higher in group B than in group A (p=0.009).

CONCLUSION

CFV could be used as a predictor of long-term left ventricular function recovery and cardiac events in patients with anterior wall AMI.

Activation of NF-kappaB is a critical element in the antiapoptotic effect of anesthetic preconditioning

Anesthetic preconditioning (APC), defined as brief exposure to inhalational anesthetics before cardiac ischemia-reperfusion (I/R), limits injury in both animal models and in humans. APC can result in the production of reactive oxygen species (ROS), and prior work has shown that APC can modify activation of NF-kappaB during I/R, with consequent reduction in the expression of inflammatory mediators. However, the role of NF-kappaB activation before I/R is unknown. Therefore, these experiments tested the hypothesis that APC-induced ROS results in activation of NF-kappaB before I/R, with consequent increased expression of antiapoptotic proteins such as Bcl-2 and decreased apoptosis. Experiments utilized an established perfused heart rat model of sevoflurane APC and I/R. The role of NF-kappaB was defined by a novel method of transient inhibition of the regulatory kinase IKK using the reversible inhibitor SC-514. In addition to functional measures of left ventricular developed and end-diastolic pressure, phosphorylation of IkappaBalpha and activation of NF-kappaB were measured along with cytosolic protein content of Bcl-2, release of cytochrome c, and degradation of caspase-3. APC resulted in ROS-dependent phosphorylation of IkappaBalpha and activation of NF-kappaB before I/R. APC also increased the expression of Bcl-2 before I/R. In addition to functional protection following I/R, APC resulted in lower release of cytochrome c and caspase-3 degradation. These protective effects of APC were abolished by transient inhibition of IkappaBalpha phosphorylation and NF-kappaB activation by SC-514 followed by washout. ROS-dependent activation of NF-kappaB by APC before I/R is a critical element in the protective effect of APC. APC reduces apoptosis and functional impairment by increasing Bcl-2 expression before I/R. Interventions that increase NF-kappaB activation before I/R should protect hearts from I/R injury.

Prognostic importance of creatine kinase and creatine kinase-MB after primary percutaneous coronary intervention for ST-elevation myocardial infarction

BACKGROUND

Although the prognostic significance of creatine kinase (CK) and creatine kinase-MB (CK-MB) after myocardial infarction has been established after thrombolysis or no reperfusion therapy, there is limited evidence of the prognostic importance after primary percutaneous coronary intervention (PCI).

METHODS

In this prospective, observational study, individual data from all patients who survived at least 2 days after primary PCI between 1991 and 2004 in our hospital were recorded. The association between enzymatic infarct size (examined by peak CK and peak CK-MB levels, each divided into tertiles) and both left ventricular ejection fraction (LVEF) and 1-year mortality was evaluated.

RESULTS

In the study group of 4670 patients, mean peak CK was 2327 U/L (SD 2008) and mean peak CK-MB was 244 U/L (SD 208). Both increased CK and CK-MB were associated with a lower LVEF. A total of 252 patients (5.4%) died between 2 days and 1 year after admission. Both peak CK and peak CK-MB were higher in those who died. Particularly, patients in the highest tertile of either peak CK or peak CK-MB had increased mortality, whereas the differences between the lower tertiles were not significant. In 2738 patients, after multivariable analysis including LVEF, the hazard ratio for 1-year mortality in patients in the highest CK tertile was 2.28 (95% CI 1.32-3.91) and for CK-MB, 1.91 (95% CI 1.11-3.26), compared to those in the other tertiles.

CONCLUSIONS

According to this large-scale study, peak CK and peak CK-MB are comparable independent predictors of LV function and 1-year mortality in patients after primary PCI.

Troponin-I concentration 72 h after myocardial infarction correlates with infarct size and presence of microvascular obstruction

OBJECTIVES

The aim of this study was to use late gadolinium hyper-enhancement cardiac magnetic resonance (LGE-CMR) imaging to determine if a 72-h troponin-I measurement would provide a more accurate estimation of infarct size and microvascular obstruction (MVO) than serial creatine kinase (CK) or early troponin-I values.

METHODS

LGE-CMR was performed 3.7+/-1.4 days after medical treatment for acute ST elevation or non-ST elevation myocardial infarction. Infarct size and MVO were measured and correlated with serum troponin-I concentrations, which were sampled 12 h and 72 h after admission, in addition to serial CK levels.

RESULTS

Ninety-three patients, of whom 71 had received thrombolysis for ST elevation myocardial infarction, completed the CMR study. Peak CK, 12-h troponin-I, and 72-h troponin-I were related to infarct size by LGE-CMR (r = 0.75, p<0.0001; r = 0.56, p = 0.0003; r = 0.62, p<0.0001 respectively). Serum biomarkers demonstrated higher values in the group with MVO compared with those without MVO (Peak CK 3085+/-1531 vs 1471+/-1135, p<0.001; 12-h troponin-I 58.3+/-46.9 vs 33.4+/-40.0, p = 0.13; 72-h troponin-I 11.5+/-9.9 vs 5.5+/-4.6, p<0.005). The correlation between the extent of MVO and 12-h troponin-I was not significant (r = 0.16), in contrast to the other serum biomarkers (peak CK r = 0.44, p<0.0001; 72-h troponin-I r = 0.46, p = 0.0002).

CONCLUSION

A single measurement of 72-h troponin-I is similar to serial CK measurements in the estimation of both myocardial infarct size and extent of MVO, and is superior to 12-h troponin-I measurements.

Estimation of infarct size by single measurements of creatine kinase levels in patients with a first myocardial infarction

OBJECTIVE

Enzymatic estimation of infarct size is desirable in the reperfusion era, because a possible discrepancy with the observed asynergic area of the left ventricle may suggest the presence of stunned myocardium. Unfortunately, timely myocardial reperfusion produces a rapid washout of creatine kinase (CK) in blood flow, which overestimates infarct size. In this perspective, we investigated whether the mid-terminal portion of the CK time-activity curve could predict infarct size more reliably.

METHODS

Enzymatic infarct size was calculated by peak CK levels, the CK area under the curve and by single CK values, in 103 patients with a first ST-elevation myocardial infarction, and compared to the left ventricular akinetic area. The wall motion asynergy score at follow-up was considered as the actual infarct size.

RESULTS

In patients with peak CK within 10 h of symptom onset, CK levels at 30 h showed a high independent correlation (r = 0.83; P < 0.001) with infarct size. In patients with late peak CK (> 10 h), CK levels at 12 h turned out to be the best predictor of infarct size (r = 0.55; P < 0.01). At multivariate regression analysis, peak CK was the best predictor of infarct size in the whole population (r = 0.61; P < 0.001).

CONCLUSIONS

In patients with ST-elevation myocardial infarction and early peak CK, infarct size at follow-up could be better estimated with single values of the mid-terminal portion of the CK time-activity curve.

Prognostic Implications of Creatine Kinase Elevation After Primary Percutaneous Coronary Intervention for Acute Myocardial Infarction

OBJECTIVES

We examined the prognostic implications of the absolute level and rate of increase of creatine kinase (CK) elevation after primary percutaneous coronary intervention (PCI).

BACKGROUND

Peak creatine kinase (CK(peak)) and the rate of CK increase are related to reperfusion success and clinical outcomes after thrombolytic therapy for acute myocardial infarction (AMI). The utility of routine serial CK monitoring after primary PCI, in which normal antegrade blood flow is restored in most patients, is unknown.

METHODS

In the Controlled Abciximab and Device Investigation to Lower Late Angioplasty Complications (CADILLAC) trial, 1,529 patients with AMI randomized to either stenting or balloon angioplasty, each with or without abciximab, had CK levels determined at baseline and at 8 +/- 1 h, 16 +/- 1 h, and 24 +/- 1 h after PCI.

RESULTS

The CK(peak) occurred at baseline in 3.9% of patients, at 8 +/- 1 h in 69.6%, at 16 +/- 1 h in 20.0%, and at 24 +/- 1 h in 6.5%. The CK levels at all post-procedural time points were significantly higher in patients who died compared with the one-year survivors, as was CK(peak) (mean, 2,865 U/l vs. 1,885 U/l, respectively, p < or = 0.001). By multivariate analysis, CK(peak) was a significant predictor of one-year mortality (hazard ratio = 2.15, p = 0.0002), independent from post-PCI Thrombolysis In Myocardial Infarction (TIMI) flow. Both the improvement in left ventricular ejection fraction from baseline to seven months and its absolute level were inversely correlated with CK(peak) (p < 0.001 for both). In contrast, the time to CK(peak) was not an independent predictor of mortality or myocardial recovery.

CONCLUSIONS

The CK(peak) after primary PCI is a powerful predictor of one-year mortality independent of other clinical and angiographic measures.

Baseline troponin level: key to understanding the importance of post-PCI troponin elevations

AIMS

The adverse prognostic significance of biomarker elevations after percutaneous coronary intervention (PCI) is well established. However, often baseline troponin values are not included in the analysis or sensitive criteria are not employed. Accordingly, we assessed the timing and magnitude of post-PCI troponin T (cTnT) levels and their relationships to outcomes in patients with and without pre-PCI baseline cTnT elevations using a sensitive assay and sensitive cut-off values.

METHODS AND RESULTS

cTnT was measured at baseline (pre-PCI), 8 and 16 h post-PCI in 2352 patients. A cTnT elevation was defined as > or =0.03 ng/mL. No baseline cTnT elevations were detected in 1619 patients undergoing mostly (97%) non-urgent procedures (cTnT = 0.01 +/- 0.002 ng/mL; mean +/- SD). 733 patients had baseline cTnT elevations. Only the baseline troponin value had prognostic importance. Patients with elevated cTnT baseline levels had a higher overall cumulative 12-month death/MI rate of 11.1% compared with those without elevated baseline levels of 4.7% (P < 0.05). Neither the timing nor the magnitude of the post-procedure cTnT elevations was predictive of long-term death/MI rates when baseline elevations were included in the analysis. Similar findings were observed for baseline creatine kinase-MB (CK-MB) levels. Late increases in cTnT levels (16 h post-PCI) presaged in-hospital events only.

CONCLUSION

Long-term prognosis is most often related to the baseline pre-PCI troponin value and not the biomarker response to the PCI. These results support a re-evaluation of the use of biomarker data in relation to PCI.

Prognostic significance of time-delay to peak creatine kinase after direct percutaneous coronary intervention in acute myocardial infarction patients

The aim of the present study was to investigate the prognostic significance of time-delay to peak creatine kinase (CK) after successful direct percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI). Our 240 consecutive first AMI attack subjects admitted within 5 hours from onset were successfully reperfused by direct PCI therapy. Subjects were divided into two groups according to the upper quartile value of peak-CK time from onset, the early peak-CK group (peak-CK time < or = 16 hours from onset, n = 180) and the late peak-CK group (peak-CK time > 16 hours, n = 60). (I) The early ST-segment resolution rate was lower in the late peak-CK group compared with the early peak-CK group (P < 0.05), and there were significantly fewer patients with preinfarction angina pectoris in the late peak-CK group than in the early peak-CK group (P < 0.01). (II) LVEF in the chronic stage was significantly lower in the late peak-CK group than in the early peak-CK group (49 +/- 13% versus 57 +/- 13%, P < 0.001). (III) There were significantly more patients with major complications in the late peak-CK group than in the early peak-CK group (required CABG: 10% versus 3%, P < 0.05; cardiac death: 18% versus 3%, P = 0.0001). (IV) Multivariate analysis identified late peak-CK as an independent predictor of cardiac death (Odds ratio 7.91, 95% C.I. 1.40-44.11, P < 0.05). In patients with AMI, the time-delay to peak-CK after successful direct PCI may be closely related to left-ventricular systolic dysfunction and poor patient outcome, including mortality.

Time-dependent changes in plasma osteopontin levels in patients with anterior-wall acute myocardial infarction after successful reperfusion: Correlation with left-ventricular volume and function

Osteopontin is a secreted extracellular-matrix glycoprotein that plays a role in the healing of remodeling tissue. We examined the relationship of plasma osteopontin levels with left-ventricular (LV) volume and function in 18 consecutive patients who underwent successful reperfusion after anterior-wall acute myocardial infarction (AMI). The plasma osteopontin level was within the control range at admission (mean +/- SD 420 +/- 195 ng/mL), began to increase on day 2 (935 +/- 464 ng/mL), and reached a maximum around day 3 (1139 +/- 482 ng/mL). The level remained high on days 4, 5, and 7 ( approximately 1000 ng/mL) and then decreased on day 14. Maximal plasma osteopontin levels and the difference between maximal and minimal levels were positively correlated with LV end-systolic volume index (r = .58, P < .05; and r = .65, P < .01, respectively) and negatively correlated with LV ejection fraction (r = -.52, P < .05; and r = -.60, P < .01, respectively). The area under the curve of plasma osteopontin levels for 14 days after AMI was significantly correlated with LV end-systolic volume index (r = .66, P < .01), LV end-diastolic volume index (r = .50, P < .05), and LV ejection fraction (r = -.55, P < .05). In subgroup patients with the same area of risk for myocardial infarction (ie, responsible lesions located at the same proximal left anterior descending coronary artery), essentially the same or a closer relationship between plasma osteopontin level and LV volume and function was noted. Plasma osteopontin levels were correlated substantially with plasma levels of high-sensitivity C-reactive protein (hsCRP) and weakly with serum creatine kinase release. In conclusion, the plasma level of osteopontin changes in a time-dependent fashion and is correlated with LV volumes and function and associated substantially with the extent of the inflammatory response indicated by the plasma hsCRP level and weakly with infarct size estimated on the basis of cardiac-enzyme release.

The quantification of infarct size

We sought to summarize the published evidence regarding the measurement of infarct size by serum markers, technetium-99m sestamibi single-photon emission computed tomography (SPECT) myocardial perfusion imaging, and magnetic resonance imaging. The measurement of infarct size is an attractive surrogate end point for the early assessment of new therapies for acute myocardial infarction. For each of these three approaches, we reviewed reports published in English providing the clinical validation for the measurement of infarct size and the relevant clinical trial experience. The measurement of infarct size by serum markers has multiple theoretical and practical limitations. The measurement of troponin is promising, but the available data validating this marker are limited. Sestamibi SPECT imaging has five separate lines of published evidence supporting its validity and has received extensive study in multicenter trials. Magnetic resonance imaging has great promise but has less clinical validation and no multicenter trial experience. Therefore, SPECT sestamibi imaging is currently the best available technique for the quantitation of infarct size to assess the incremental treatment benefit of new therapies in multicenter trials of acute myocardial infarction.

Timing of Peak Troponin T and Creatine Kinase-MB Elevations After Percutaneous Coronary Intervention

STUDY OBJECTIVE

The prognostic significance of elevations in creatine kinase-MB and troponin T (cTnT), which have been conventionally measured 6 to 8 h after percutaneous coronary intervention (PCI), has been established. However, the time to peak biomarker appearance in the circulation has not been defined and is the purpose of this pilot study.

DESIGN

Nonrandomized, nonconsecutive patient cohort.

SETTING

Clinical practice, Mayo Clinic, Rochester, MN.

PATIENTS

Cohort (n = 57) undergoing elective PCI.

INTERVENTIONS

cTnT and creatine kinase (CK)-MB measured at baseline, 2 h, 4 h, 8 h, and > or = 2 h (mean +/- SEM, 18 +/- 5 h) after PCI.

MEASUREMENTS AND RESULTS

Postprocedure cTnT elevations were detected in 30 of 57 patients (53%). Of these, 4 of 30 patients (13%) had peak cTnT at 4 h (0.80 +/- 0.40 ng/mL), 5 of 30 patients (17%) had peak cTnT at 8 h (1.07 +/- 0.48 ng/mL), and 21 of 30 patients (70%) had peak cTnT at > or = 12 h (0.21 +/- 0.06 ng/mL); 22 of 30 patients received abciximab. Elevations in CK-MB occurred in 14 of 57 patients (25%). Of these, 3 of 14 patients (21%) demonstrated peak CK-MB at 2 h (18.5 +/- 7.9 ng/mL) and the remainder (11 of 14 patients, 79%) during the 12- to 20-h interval (20.2 +/- 4.4 ng/mL); 12 of 14 patients received abciximab.

CONCLUSION

More cTnT than CK-MB elevations occur after PCI; however, both biomarkers demonstrate a longer time to peak value than anticipated in clinical practice. Early surveillance monitoring (< 12 h) does not detect peak biomarker levels, especially in patients with normal baseline values. If peak levels are to be used to determine prognosis, then longer time intervals should be used for post-PCI surveillance. The timing of peak elevations appears to be influenced by baselines values as well. Early elevations may reflect the conjoint effects of injury associated with the disease process and the intervention itself. These data suggest that a re-evaluation of surveillance monitoring to account for the variability reported and the influence of baseline elevations of biomarkers may improve the prognostic power of the measurements.

An early and complete reperfusion strategy for acute myocardial infarction using fibrinolysis and subsequent transluminal therapy--The FAST trial

The efficacy and safety of fibrinolysis and subsequent transluminal (FAST) therapy were evaluated in 195 patients with acute myocardial infarction (AMI) for the early achievement of thrombolysis-in-myocardial-infarction grade 3 (TIMI-3) flow in the infarct-related artery. Intravenous thrombolysis using the optimal dose of a thrombolytic agent was initiated immediately after arrival in the emergency room, followed by coronary angiography and adjuvant percutaneous coronary intervention. A comparison of the thrombolysis alone (n=83) and thrombolysis plus intervention (n=112) groups showed significant differences in the time interval from hospital arrival to achievement of TIMI-3 flow (66.2+/-23.7 vs 111.6+/-29.6 min, p<0.0001), creatine kinase-MB release (295+/-201 vs 468+/-322 U/L, p=0.0003) and peak troponin T (23.6+/-16.9 vs 38.9+/-25.9 ng/ml, p<0.0001). No significant differences were observed in either 30-day mortality or complications. The TIMI-3 flow at the initial angiography was significantly higher with a single bolus of mutant tissue-type plasminogen activator (t-PA) monteplase than with an accelerated infusion of t-PA (60% vs 32%, p=0.005). In conclusion, the early restoration of TIMI-3 flow by FAST therapy reduced the degree of myocardial damage with a low risk of complications. TIMI-3 flow was achieved at an earlier stage with monteplase and this agent may be beneficial in the FAST therapy.

Transmural extent of acute myocardial infarction predicts long-term improvement in contractile function

BACKGROUND

Previous animal studies have demonstrated that the transmural extent of acute myocardial infarction defined by contrast-enhanced MRI (ceMRI) relates to early restoration of flow and future improvements in contractile function. We tested the hypothesis that ceMRI would have similar predictive value in humans.

METHODS AND RESULTS

Twenty-four patients who presented with their first myocardial infarction and were successfully revascularized underwent cine and ceMRI of their heart within 7 days (scan 1) of the peak MB band of creatine kinase. Cine MRI was repeated 8 to 12 weeks later (scan 2). The transmural extent of infarction on scan 1 and wall thickening on both scans were determined using a 72-segment model. A total of 524 of 1571 segments (33%) were dysfunctional on scan 1. Improvement in segmental contractile function on scan 2 was inversely related to the transmural extent of infarction on scan 1 (P=0.001). Improvement in global contractile function, as assessed by ejection fraction and mean wall thickening score, was not predicted by peak creatine kinase-MB (P=0.66) or by total infarct size, as defined by MRI (P=0.70). The best predictor of global improvement was the extent of dysfunctional myocardium that was not infarcted or had infarction comprising <25% of left ventricular wall thickness (P<0.005 for ejection fraction, P<0.001 for mean wall thickening score).

CONCLUSION

In patients with acute myocardial infarction, the transmural extent of infarction defined by ceMRI predicts improvement in contractile function.

Reperfusion injury after focal myocardial ischaemia: polymorphonuclear leukocyte activation and its clinical implications

The only way to rescue ischaemic tissue is to re-instate the oxygen supply to the tissue. However reperfusion of the ischaemic area not only oxygenates the tissue but also initiates a cascade of processes, which may in some cases result in temporary dysfunction of the myocardium. In order to devise protective measures, it is essential to understand the mechanisms and the triggers of this reperfusion phenomenon. In this review we will mainly focus on the inflammatory response caused by reperfusion. We will cover the different steps of polymorphonuclear leukocyte activation and will briefly discuss the molecular biology of the receptors involved. The currently used pharmacological medications in acute cardiology will be reviewed and in particular their actions on polymorphonuclear leukocyte activation, adhesion and degranulation. This review is a compilation of the current knowledge in the field and the therapeutic progress in the prevention of reperfusion injury made today.

Relation of temporal creatine kinase-MB release and outcome after thrombolytic therapy for acute myocardial infarction. TAMI Study Group

Measuring biochemical marker release after acute myocardial infarction helps in estimating infarct size and prognosis. We sought to relate in-hospital outcomes and curve-fitted creatine kinase (CK)-MB variables after thrombolysis. We measured CK-MB mass initially and at 30 and 90 minutes, and at 3, 8, and 20 hours after thrombolysis in 130 patients also undergoing cardiac catheterization at 90 minutes and at 5 to 7 days. Data were fitted, and maximums and curve areas calculated. CK-MB maximums related to infarct location (p = 0.014) and time to therapy (p = 0.002); curve area did not. Neither maximums nor curve area related to Thrombolysis in Myocardial Infarction trial flow grade at 90 minutes. Maximums related to ejection fraction at 90 minutes (p = 0.0004) and at 5 to 7 days (p = 0.0014), as did curve area (p = 0.0076 and 0.030, respectively). Maximums related to infarct zone function at 90 minutes (p = 0.024) and at 5 to 7 days (p = 0.042); curve area related only at 90 minutes (p = 0.027). Both maximums and curve area predicted congestive heart failure (p = 0.008 and p = 0.042, respectively) and a composite of congestive heart failure or death (p = 0.004 and p = 0.047, respectively); however, after adjusting for maximums, curve area no longer predicted congestive heart failure (p = 0.92). Maximums predicted the composite outcome after adjustment for curve area, and showed a trend toward predicting congestive heart failure (p = 0.089). We conclude that CK-MB maximums relate to infarct zone function, left ventricular function, and in-hospital outcomes after thrombolysis for acute myocardial infarction.

Relationship between myocardial cation content and injury in reperfused rat hearts treated with cation channel blockers

A role for K+ and Ca2+ channel blockers in cardiac contractile dysfunction and myocardial ionic imbalance was examined in isolated rat hearts with 35-min ischemia and 60-min reperfusion. The K+ channel blockers glibenclamide (1-30 microM) and sematilide (1-30 microM), Ca2+ channel blockers diltiazem (0.1-3 microM) and nicardipine (0.03-1 microM) and fast Na+ channel blocker tetrodotoxin (0.01-0.3 microM) were delivered for the last 3-min pre-ischemia. Ischemia-induced increase in Na+ content was attenuated by diltiazem and tetrodotoxin at all concentrations employed and by nicardipine at 0.3 microM, whereas the ischemia-induced loss of K+ was suppressed partially by glibenclamide and sematilide and almost completely by the two drugs in combination. Left ventricular developed pressure of untreated hearts did not recover upon reperfusion, which was associated with increases in myocardial Na+ and Ca2+ contents and decreases in K+ and Mg2+ contents. Glibenclamide and sematilide neither enhanced the post-ischemic recovery of left ventricular developed pressure nor affected cation changes during reperfusion. Diltiazem enhanced the recovery of left ventricular developed pressure and attenuated imbalance of the myocardial Na+ during ischemia and of all myocardial cations examined during reperfusion. The effects of nicardipine on these parameters were small. Tetrodotoxin enhanced the recovery of left ventricular developed pressure and reversed the imbalance of all myocardial cations examined during reperfusion in a concentration-dependent manner. The results suggest that blockade of transmembrane flux of K+ during ischemia plays a minor role in the improvement of post-ischemic contractile recovery, rather blockade of transmembrane flux of Na+ attenuates the ischemia and reperfusion injury.

New method of estimating myocardial infarct size using technetium-99m pyrophosphate and thallium-201 dual single photon emission computed tomography imaging

A new method was devised to estimate infarct size using dual single photon emission computed tomography with thallium-201 and technetium-99m pyrophosphate. Designating the ratio of infarct area to whole myocardial volume as %MI, the correlation of %MI with other markers of left ventricular dysfunction was examined: peak creatine kinase, ejection fraction and left ventricular asynergy. As %MI correlated well with these markers, it is considered that %MI will be useful for estimating infarct size and predicting the severity of left ventricular dysfunction in the early stage of acute myocardial infarction.

Time-dependent changes of serum carboxy-terminal peptide of type I procollagen and carboxy-terminal telopeptide of type I collagen concentrations in patients with acute myocardial infarction after successful reperfusion: correlation with left ventricular volume indices

To test the hypothesis that in patients with acute myocardial infarction (AMI), changes in the concentrations of the serum carboxy-terminal peptide of type I procollagen (PICP) and the carboxy-terminal telopeptide of type I collagen (ICTP) reflect extracellular matrix reformation and degradation, respectively, in the infarct healing processes, we measured these serum concentrations by RIA and compared their values with left ventricular (LV) indices obtained by left ventriculography. We studied 13 consecutive patients with their first AMI who underwent successful reperfusion. Blood samples were taken the day of admission and on days 2, 3, 4, 5, 7, and 14. LV volume indices were determined at 1 month after AMI, when LV remodeling was almost completed. The serum concentrations of both PICP and ICTP changed in a time-dependent manner. The average serum PICP concentration was lower than 1 SD below the mean control values on days 2 and 3 and increased thereafter, returning to the lower end of the control range at day 14. The area under the curve (AUC) for PICP was significantly correlated with the LV end systolic (ES) and end diastolic (ED) volume indices and LV ejection fraction for the first 14 days after AMI. The serum PICP on days 5–14 was inversely correlated or tended to be correlated with the LVES and LVED volume indices. The average serum ICTP concentrations on admission were within the control range, began to increase on day 2, and reached maximal concentrations on day 5, remaining at a plateau concentration until day 14. Although the AUC of ICTP for 14 days, the ICTP concentrations on days 1 and 14, and the minimal and maximal concentrations were significantly correlated with creatine kinase (CK) release and the period from AMI onset to the peak CK time, the concentrations were not significantly correlated with any LV indices except for the concentration on day 4, which was weakly correlated with the LVES volume index. The serum concentrations of PICP showed a significant time-dependent change that correlated with LV indices, indicating that PICP may provide additional information for evaluating the healing process because it affects LV remodeling after AMI. Although the serum concentration of ICTP changed in association with CK release, the ICTP concentration was found to be a poor indicator for LV indices.

Thrombolytic therapy does not change the release ratios of enzymatic and non-enzymatic myocardial marker proteins

Measurements of cardiac marker proteins in plasma from patients with acute myocardial infarction (AMI) have become important in the evaluation of recanalization therapy. The validity of this approach has however been questioned, because it was claimed that coronary reperfusion may increase the recovery in plasma of cardiac enzymes, such as creatine kinase (CK). In the present study, possible effects of thrombolytic therapy on the release of enzymatic and nonenzymatic marker proteins were investigated. Activities of CK and lactate dehydrogenase (LDH), and concentrations of myoglobin (Mb) and fatty acid-binding protein (FABP) were determined in serial plasma samples obtained from 50 patients with confirmed AMI, of whom 36 received thrombolytic therapy, and 14 did not. Treatment delay was 2.8+/-1.6 (mean+/-SD) h, and hospital delay in untreated patients was 2.7+/-1.8 h. Average infarct size, expressed in gram-equivalents of heart muscle per litre of plasma (g-eq/l), varied between 5.5 and 7.2 g-eq/l for the four marker proteins in patients treated with thrombolytic therapy, and between 4.6 and 6.4 g-eq/l in untreated patients, with a tendency to larger infarct sizes for Mb and FABP than for CK and LDH. Thrombolytic therapy, although significantly accelerating protein release rates, did not influence the release ratios. These results indicate that thrombolytic therapy has no significant effects on the recovery of cardiac marker proteins in plasma.

Influence of collateral circulation on in-hospital death from anterior acute myocardial infarction

OBJECTIVES

Our purpose was to study whether the in-hospital prognosis of anterior acute myocardial infarction (AMI) is influenced by preexistent collateral circulation to the infarct-related artery.

BACKGROUND

Collateral circulation exerts beneficial influences on the clinical course after AMI, but demonstration of improved survival is lacking.

METHODS

We studied 238 consecutive patients with anterior AMI treated by primary angioplasty within the first 6 h of the onset of symptoms. Fifty-eight patients with basal Thrombolysis in Myocardial Infarction (TIMI) flow >1 in the infarct-related artery or with inadequate documentation of collateral circulation were excluded. Collateral channels to the infarct-related artery before angioplasty were angiographically assessed, establishing two groups: 115 patients (64%) without collateral vessels (group A) and 65 patients (36%) with collateral vessels (group B).

RESULTS

There were no differences in baseline characteristics between groups A and B, except for the greater prevalence of previous angina in group B (15% vs. 34%, p = 0.003). During the hospital stay, 26 patients (23%) in group A and 5 (8%) in group B died (p = 0.01). Cardiogenic shock accounted for 74% of deaths. Cardiogenic shock developed in 30 patients (26%) in group A and in 4 (6%) in group B (p = 0.001). The absence of collateral circulation appeared to be an independent predictor of in-hospital death (odds ratio 3.4, 95% confidence interval 1.2 to 9.6, p = 0.02) and cardiogenic shock (odds ratio 5.6, 95% confidence interval 1.9 to 17, p = 0.002).

CONCLUSIONS

Preexistent collateral circulation decreases in-hospital death from anterior AMI by reducing the incidence of cardiogenic shock.

Estimation of enzymatic infarct size: direct comparison of the marker enzymes creatine kinase and alpha-hydroxybutyrate dehydrogenase

BACKGROUND

Estimation of infarct size with serum-time activity curves of creatine kinase (CK) (or CKMB) or alpha-hydroxybutyrate dehydrogenase (HBDH) is widely used in clinical trials. However, an independent variable such as left ventricular function has not been directly compared with CK and HBDH infarct size measurements in the same group of patients.

METHODS AND RESULTS

Infarct size was calculated by the CK area under the curve (AUC) and by the cumulative release of HBDH in 90 patients with acute myocardial infarction undergoing early thrombolysis. Infarct size estimates by CK AUC and HBDH release were closely correlated (r = 0.88, p < 0.0001). HBDH release was significantly better (p < 0.001) correlated to angiographically assessed ejection fraction 8 days after infarction (r = 0.74) than to CK AUC (r = 0.60), as was maximum HBDH (r = 0.71) compared with CK maximum (r = 0.59). In contrast to CK, maximum levels of HBDH only slightly overestimate myocardial damage in patients with early reperfusion. Data reanalyzed from the former placebo-controlled Intravenous Streptokinase in Acute Myocardial Infarction (ISAM) study revealed significant differences in favor of streptokinase for CK and CKMB AUC and for HBDH maximum, but no difference for CK and CKMB maximums.

CONCLUSIONS

For comparative clinical trials HBDH appears to be the preferable marker enzyme for estimates of infarct size and measure of reperfusion effectiveness. In clinical practice one routine measure of HBDH serum activity on the second day after infarction may be a useful approximate value of infarct size.

Dissociation between changes in intramyocardial function and left ventricular volumes in the eight weeks after first anterior myocardial infarction

OBJECTIVES

We sought to examine the relation between regional changes in intramyocardial function and global left ventricular (LV) remodeling in the first 8 weeks after reperfused first anterior myocardial infarction (MI).

BACKGROUND

Because of limitations in imaging methods used to date, this relation has not been thoroughly evaluated.

METHODS

We studied 26 patients (21 men, 5 women; mean age 51 years) by magnetic resonance imaging (MRI) on day 5 +/- 2 (mean +/- SD) and week 8 +/- 1 after their first anterior MI. All patients had single-vessel left anterior descending coronary artery disease and although they had received reperfusion therapy, all had regional LV dysfunction and an initial ejection fraction (EF) < or = 50%. Short-axis magnetic resonance tagging was performed spanning the LV. Percent intramyocardial circumferential shortening (%S) on a topographic basis, LV mass index, LV end-diastolic volume index (LVEDVI), LV end-systolic volume index and LV ejection fraction (LVEF) were measured.

RESULTS

Left ventricular mass index tended to decrease, whereas the LVEDVI increased from 82 +/- 24 to 96 +/- 27 ml/m2 (p = 0.002). Left ventricular end-systolic volume index remained unchanged, whereas LVEF increased from 39 +/- 12% to 45 +/- 14% (p = 0.002). Apical %S improved from 9 +/- 6% to 13 +/- 5% (p < 0.0001), as it did in the midanterior (6 +/- 6% to 10 +/- 7%, p < 0.02) and midseptal regions (8 +/- 7% to 12 +/- 6%, p < 0.02). Early dysfunction in remote midinferior and basal lateral regions resolved by 8 weeks. By multivariate analysis, the only significant predictor of an increase in LVEDVI over the study period was peak creatine kinase (p = 0.04).

CONCLUSIONS

In the first 8 weeks after a large, reperfused anterior MI, %S improved in the apex, midanterior and midseptal regions and normalized in remote noninfarct-related regions, but LV end-diastolic volumes also increased. This increased LVEDVI correlated with infarct size by peak creatine kinase and was not related to changes in global and regional LV function.