A new approach for the enzymatic estimation of infarct size: serum peak creatine kinase and time to peak creatine kinase activity

Inhibiting the Inflammatory Injury After Myocardial Ischemia Reperfusion With Plasma-Derived Alpha-1 Antitrypsin: A Post Hoc Analysis of the VCU-α1RT Study

BACKGROUND

Despite the benefits of reperfusion in limiting myocardial injury, the infarct size continues to expand after reperfusion because of secondary inflammatory injury. Plasma-derived alpha-1 antitrypsin (AAT) inhibits the inflammatory injury in myocardial ischemia and reperfusion. To explore the effects of plasma-derived AAT on the inflammatory response to ischemia-reperfusion injury, we analyzed time-to-reperfusion and enzymatic infarct size estimates in a post hoc analysis of the VCU-α1RT clinical trial (clinicaltrials.gov NCT01936896).

METHODS

Ten patients with ST-segment elevation acute myocardial infarction (STEMI) were enrolled in an open-label, single-arm treatment study of Prolastin C, plasma-derived AAT, at 60 mg/kg infused intravenously within 12 hours of reperfusion. Biomarkers were measured serially over the first 72 hours, and patients were followed clinically for the occurrence of new-onset heart failure, recurrent MI, or death. Twenty patients with STEMI who had been enrolled in previous randomized trials with identical inclusion/exclusion criteria and had been assigned to placebo served as historical controls.

RESULTS

Time to percutaneous coronary intervention and time to drug did not significantly differ between groups. AAT-treated patients had a significantly shorter time-to-peak creatine kinase myocardial band (CK-MB) values (525 [480-735] vs. 789 [664-959] minute, P = 0.005) and CK-MB area under the curve (from 1204 [758-2728] vs. 2418 [1551-4289] U·day, P = 0.035), despite no differences in peak CK-MB (123 [30-196] vs. 123 [71-213] U/mL, P = 0.71).

CONCLUSIONS

A single administration of Prolastin C given hours after reperfusion in patients with STEMI led to a significant shorter time to peak and area under the curve for CK-MB, despite similar peak CK-MB values. These preliminary data support the hypothesis that Prolastin C shortens the duration of the ischemia-reperfusion injury in patients with STEMI.

Comparison of Outcomes of Patients With ST-Segment Elevation Myocardial Infarction Treated by Primary Percutaneous Coronary Intervention Analyzed by Age Groups (<75, 75 to 85, and >85 Years); (Results from the Bremen STEMI Registry)

As old patients, who were treated by percutaneous coronary interventions (PCI) for ST-segment elevation myocardial infarction (STEMI), are regularly excluded or underrepresented in randomized trials, data on treatment and outcomes of this patient group at high risk have to be collected by registries. The study population of the German Bremen STEMI Registry was divided into the age groups G1: <75 years (n = 4,108, young), G2: 75 to 85 years (n = 1,032, old), and G3: >85 years (n = 216, very old) and was evaluated for clinical management and course. PCI failure (Thrombolysis In Myocardial Infarction flow 0 or 1 after PCI) was observed more often with increasing age. Patients >85 years without successful PCI had a very high inhospital mortality (40.0% without PCI success vs 18.1% with PCI success, p <0.05). Despite a reduced rate of periinterventional treatment with glycoprotein IIb/IIIa inhibitors in elderly patients of G2 and G3, inhospital bleedings (Thrombolysis In Myocardial Infarction/Bleeding Academic Research Consortium ≥2) occurred more frequently in these patients (G1: 5.4% vs G2: 11.0% vs G3: 19.6%, p <0.0001). Mortality rates during inhospital and long-term course increased with increasing age. In a multivariate analysis successful PCI was associated with improved outcomes in all age groups; even in very old patients successful PCI was associated with a significantly lower inhospital mortality rate (odds ratio 0.26, 95% confidence interval 0.08 to 0.81) and a trend toward a lower 1-year mortality. In conclusion, the present "real-world" data demonstrate an elevated rate of PCI failure, bleeding complications, and mortality in elderly patients treated by primary PCI for STEMI. However, a beneficial effect of successful PCI on mortality was observed in all age groups, even in very old patients, indicating the crucial role of revascularization therapy.

Endothelial nitric oxide synthase genotypes modulate peripheral vasodilatory properties after myocardial infarction

BACKGROUND

Studies in population genetics suggest an important relationship between the eNOS G894T polymorphism and occurrence of acute myocardial infarction (AMI), with little known on its influence on the post-AMI period.

AIM

To investigate the association of allelic variants produced by the G894T transversion in eNOS (rs1799983) with post-AMI variables.

METHODS

Cross-sectional analyses of anthropometric, clinical and laboratory assessments obtained within the first 24h and after 5 and 30 days of the AMI event across T carriers and G homozygotes of eNOS in 371 consecutive cases of AMI with ST-segment elevation admitted to a Brazilian emergency service in cardiology. Genotypes were determined by polymerase chain reaction followed by enzymatic restriction.

RESULTS

Despite no difference between genotypic groups on aspects as Killip-Kimbal classification scores, extension of infarcted mass, lipid profile or pattern of medication use, an increase in serum nitric oxide from admission to day 5 was higher for T carriers (p<0.001). Thirty days post-AMI, peripheral blood flow reserve was larger among T carriers either by flow- (p=0.037) and nitrate-mediated (p=0.040) dilation testing.

CONCLUSION

Our results suggest an association of the eNOS 894T allele with an apparent improvement in late arterial function in post-AMI patients.

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.

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.

Q-wave regression after acute myocardial infarction assessed by Tl-201 myocardial perfusion SPECT

BACKGROUND

The actual relationship between the interval change of myocardial thallium 201 (Tl-201) radioactivity in the infarct area and the pattern of Q-wave regression is still unknown. This study was conducted to evaluate their relationship after acute myocardial infarction (AMI).

METHODS AND RESULTS

A total of 30 patients who had a first Q-wave AMI (11 without Q-wave regression and 19 with Q-wave regression) were retrospectively included. Two sets of 12-lead surface electrocardiograms and Tl-201 myocardial perfusion images were obtained 0 to 2 months and 14 to 84 months after the AMI event, respectively. The acute/subacute redistribution Tl-201 radioactivity was similar between the patients with and those without Q-wave regression. However, the patients with Q-wave regression had higher chronic redistribution Tl-201 radioactivity than those without Q-wave regression. Moreover, the patients with Q-wave regression presented a higher gradient in the redistribution Tl-201 radioactivity between the chronic and acute/subacute images than those without Q-wave regression.

CONCLUSIONS

This study supports the role of functional recovery of stunning and/or hibernating myocardium in the disappearance of Q waves after AMI.

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.

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.

Time dependent alterations of serum matrix metalloproteinase-1 and metalloproteinase-1 tissue inhibitor after successful reperfusion of acute myocardial infarction

OBJECTIVE

To test the hypothesis that changes in serum matrix metalloproteinase-1 (MMP-1) and tissue inhibitors of metalloproteinase-1 (TIMP-1) after acute myocardial infarction reflect extracellular matrix remodelling and the infarct healing process.

PATIENTS

13 consecutive patients with their first acute myocardial infarction who underwent successful reperfusion.

METHODS

Blood was sampled on the day of admission, and on days 2, 3, 4, 5, 7, 14, and 28. Serum MMP-1 and TIMP-1 were measured by one step sandwich enzyme immunoassay. Left ventricular volume indices were determined by left ventriculography performed four weeks after the infarct.

RESULTS

Serum concentrations of both MMP-1 and TIMP-1 changed over time. The average serum MMP-1 was more than 1 SD below the mean control values during the initial four days, increased thereafter, reaching a peak concentration around day 14, and then returned to the middle control range. Negative correlations with left ventricular end systolic volume index and positive correlations with left ventricular ejection fraction were obtained for serum MMP-1 on day 5, when it began to rise, and for the magnitude of rise in MMP-1 on day 5 compared to admission. Serum TIMP-1 at admission was more than 1 SD below the mean control value, and increased gradually thereafter, reaching a peak on around day 14. Negative correlations with left ventricular end systolic volume index and positive correlations with left ventricular ejection fraction were obtained for serum TIMP-1 on days 5 and 7, and for the magnitude of rise in TIMP-1 on days 5 and 7 compared to admission.

CONCLUSIONS

Both MMP-1 and TIMP-1 showed significant time dependent alteration after acute myocardial infarction. Thus MMP-1 and TIMP-1 may provide useful information in evaluating the healing process as it affects left ventricular remodelling after acute myocardial infarction.

Influence of early coronary reperfusion on QT interval dispersion after acute myocardial infarction

We studied the influence of early coronary reperfusion on QT interval dispersion in patients with acute myocardial infarction (MI). There were 54 males and 18 females with a mean age of 60 +/- 10 years. Of the 51 patients with recanalization of the infarct related vessel in the recovery phase, 28 (group A) had early coronary reperfusion (5.5 +/- 2.7 hours), 23 other patients (group B) were not confirmed with early coronary reperfusion. Twenty-one patients (group C) did not undergo recanalization of the infarct related vessel in the recovery phase. Corrected QT (QTc) maximum, QTc minimum, and QTc dispersion calculated as the difference between the maximum and minimum QTc intervals, were compared among these three groups at both acute and recovery phase. At the acute phase after MI, there were no significant differences in the QTc maximum, QTc minimum, QT dispersion, and QTc dispersion among these three groups. At the recovery phase after MI, there were also no significant differences in the QTc maximum and QTc minimum. However, there were significant differences in the QT dispersion (0.035 +/- 0.010 in group A, 0.049 +/- 0.015 in group B, and 0.061 +/- 0.031 s in group C, respectively; P = 0.0001), and QTc dispersion (0.038 +/- 0.012 in group A, 0.050 +/- 0.015 in group B, and 0.063 +/- 0.032 s in group C, respectively; P = 0.0003) among the three groups. Comparison of QTc dispersion between acute and recovery phase revealed significant reduction from acute to recovery phase in group A. The number of premature ventricular contraction was lower in group A and B than group C. In summary, early coronary reperfusion may reduce electrophysiological instability by reducing QT dispersion in the recovery phase after acute MI.

Is ST segment re-elevation associated with reperfusion an indicator of marked myocardial damage after thrombolysis?

OBJECTIVES

The significance of ST segment re-elevation at reperfusion by thrombolysis was evaluated.

BACKGROUND

The significance of ST re-elevation has not been studied. Hence, we evaluated whether ST re-elevation is an indicator of marked myocardial necrosis after reperfusion.

METHODS

Twelve-lead electrocardiograms were recorded serially, before thrombolysis and immediately after each coronary angiographic procedure during thrombolysis.

RESULTS

In 32 patients with acute myocardial infarction, 15 showed transient ST re-elevation at reperfusion (group 1) and 17 showed reduction (group 2). Peak creatine kinase (CK) and CK-MB isoenzyme activity levels were significantly higher in group 1 than in group 2. Twelve patients in group 1 had strongly positive findings on early technetium-99m pyrophosphate scintigraphy, compared with one patient in group 2 (p < 0.001). The regional ejection fraction did not increase from the acute phase to the chronic phase in group 1. The ST deviation before thrombolysis was significantly greater in group 1 than in group 2 (p < 0.001). All 14 patients in group 1 showed Thrombolysis in Myocardial Infarction (TIMI) grade 0 flow and 12 of these patients did not have good collateral flow before thrombolysis.

CONCLUSIONS

These data suggest that 1) ST re-elevation at reperfusion is a sign of limited myocardial salvage by thrombolysis, and 2) high ST elevation and TIMI grade 0 flow without good collateral flow before thrombolysis may be predictive variables for marked myocardial necrosis after reperfusion.

Effects of early thrombolytic therapy (anistreplase versus streptokinase) on enzymatic and electrocardiographic infarct size in acute myocardial infarction. TEAM-2 Investigators

The effects of thrombolytic therapy on enzymatic and electrocardiographic indexes of myocardial infarction were examined in 370 patients who were enrolled within 4 hours of onset of symptoms and were randomized to blinded therapy with intravenous anistreplase (30 U/5 min, n = 188) or streptokinase (1.5 million IU/1 hour, n = 182). Creatine kinase and its MB isoenzyme were initially measured every 4 to 6 hours, and lactic dehydrogenase (LDH) and its cardiac isoenzyme (LDH-1) every 8 to 12 hours. Electrocardiograms were obtained before, and at 90 minutes and 8 hours after starting thrombolysis, and on discharge. Enzymatic and electrocardiographic measures of infarction were compared between drug treatment and patency groups. Early patency was associated with significant reductions in peak values for each of 4 cardiac enzymes (averaging 21 to 25%, p less than 0.01 to 0.001), even though later rescue procedures were often used in the nonpatient group; times to peaks were also reduced for 3 of the enzymes. Treatment with anistreplase was associated with enzymatic peaks that tended to be lower than with streptokinase (6 to 16%), approaching or reaching significance for LDH (p less than or equal to 0.07) and LDH-1 (p less than or equal to 0.04); times to peaks were similar. Early patency favorably affected electrocardiographic indexes. Summed ST-segment elevations resolved more rapidly (p less than or equal to 0.04), summed Q-wave amplitude was reduced by 32% (p less than or equal to 0.01), and total QRS infarct score on discharge was 22% less (p less than or equal to 0.006) in those achieving early patency. Small differences in electrocardiographic indexes between the 2 drug treatment groups were not significant. These results support use of early reperfusion to reduce infarct size in acute myocardial infarction with administration of streptokinase and anistreplase.

Time course of creatine kinase release after termination of sustained ventricular dysrhythmias

Differentiation between primary and secondary (caused by acute myocardial infarction) ventricular fibrillation has important therapeutic and prognostic implications. The diagnosis of myocardial infarction is based on clinical, ECG, and creatine kinase MB isoenzyme (MBCK) activity. Enzymatic criteria might not be able to confirm the diagnosis of myocardial infarction after recent cardioversion. The routine use of electrophysiologic studies involving the induction and termination of ventricular dysrhythmias provides a setting in which enzyme release as a result of cardioversion alone can be examined. Therefore a systematic investigation of the magnitude and time course of creatine kinase (CK) and MBCK release was performed after termination of ventricular dysrhythmias in 57 patients undergoing electrophysiologic studies. Of patients requiring external cardioversion, only 50% had an elevation in CK and MBCK activity. Elevation when present corrected with the number of shocks and cumulative energy delivered. The magnitude of MBCK release exceeded 10% of the total CK activity in 9% of observations. Pace-termination of ventricular tachycardia did not result in enzyme release. Arrhythmia characteristics, coronary artery disease, and left ventricular function did not affect the magnitude of the time course of enzyme release. These data suggest that cardioversion with multiple shocks may result in a component of MBCK release, and thus a false positive diagnosis of primary acute myocardial infarction may be made by relying exclusively on the enzyme release pattern.

Serum CK-MB is useful in diagnosis of acute myocardial infarction after total hip arthroplasty

Skeletal muscle trauma and myocardial infarction both increase the serum values of the creatine kinase isoenzyme MB (CK-MB) which may render the diagnosis of perioperative myocardial infarction in major orthopaedic surgery more difficult. The significance of postoperative changes in CK-MB was studied in 30 patients subjected to total hip replacement (THR), and the results were compared to CK-MB in 30 nonsurgical patients with acute myocardial infarction (AMI). AMI patients had significantly higher serum CK-MB values at 24 h than THR patients. However, the highest value after THR exceeded the lowest value in AMI. The results suggest that skeletal muscle release of CK-MB after THR is slight. CK-MB thus also seems useful in the diagnosis of AMI in postoperative patients.

Calcium-channel blockers in acute myocardial infarction

The calcium-channel blockers are useful in treating a variety of cardiovascular disorders. Due to their antiischemic and spasmolytic properties, these agents have been studied in the prophylaxis and treatment of acute myocardial infarction. This article reviews this application with respect to reduction of mortality, infarct size, and reinfarction rate. Of the agents currently available for clinical use, nifedipine has been studied most extensively. This agent shows no beneficial effects in this setting and its use may in fact be harmful. Of the few trials that have been conducted with verapamil, none have shown decreased mortality. Verapamil may reduce infarct size although further confirmation is required. Diltiazem is the only agent that has been shown to have short- and long-term benefits in the patient with acute myocardial infarction. Proper patient selection is of utmost importance in ensuring successful therapy. In particular, those patients with non-Q-wave infarctions and/or normal left ventricular function can be expected to derive the most benefit in terms of reducing mortality and reinfarction rate associated with the acute event.

Prognostic significance of an early rise to peak creatine kinase after acute myocardial infarction

Because an early rise to peak creatine kinase (CK) is regarded as a noninvasive marker of early coronary reperfusion, the short- and long-term significance of this phenomenon was studied. In a series of consecutive patients admitted between 1974 and 1976 with acute myocardial infarction (AMI), 2 hourly CK estimations were performed. Complete CK curves were obtained in 102 patients, all of whom have been followed for 10 years. Without reference to their clinical course or follow-up, patients were divided into those with CK curves peaking less than or equal to 15 hours (mean 11 hours; n = 41) and those with curves peaking greater than 15 hours (mean 21 hours; n = 61). There were no differences in age, Norris index, location of AMI or past history of coronary artery disease between the groups; however, the mean peak CK was higher in the late peak group (p less than 0.05) and there were more non-Q-wave infarcts in the early peak group (p less than 0.01). In the first 9 months of follow-up there were fewer cardiac deaths in the early peak group (5 vs 13%), but this difference was not significant, and at 12 months the survival curves crossed. At 10 years, survival was 42% in the early peak group and 65% in the late peak group (p less than 0.05). Cox regression analysis showed that early peaking of the CK curve was an independent marker for cardiac death overall (relative risk 2.3, p less than 0.02). In 1-year survivors the relative risk increased to 3.8 (p less than 0.008).(ABSTRACT TRUNCATED AT 250 WORDS)

Prognostic implications of an early peak in plasma MB creatine kinase in patients with acute myocardial infarction

To determine the prognostic implications of an early peak in plasma MB creatine kinase (MB CK) in patients with acute myocardial infarction who were not treated with an acute intervention, 342 patients with myocardial infarction confirmed by MB CK were retrospectively studied. The patients were classified into those with an early peak MB CK (less than or equal to 15 hours after the onset of symptoms, n = 84) and those with a late peak MB CK (greater than 15 hours after the onset of symptoms, n = 258). Patients with an early peak MB CK were slightly older, were more frequently female and had a higher incidence of prior myocardial infarction, congestive heart failure and arrhythmias compared with patients with a late peak MB CK. Patients with an early peak MB CK more frequently presented with ST segment depression (23 versus 11%, p less than 0.01), with anterior location of ischemia or infarction (71 versus 52%, p less than 0.01) and with a lower mean left ventricular ejection fraction (41.4 versus 47.4%, p less than 0.01). Despite more extensive left ventricular dysfunction at initial presentation, patients with an early peak MB CK had a smaller mean MB CK infarct size index (12.6 versus 18.9 g-Eq/m2, p less than 0.01), with no difference in the incidence of in-hospital complications, including death. The early left ventricular dysfunction improved in the patients with an early peak MB CK, evidenced by a 4.5% increase in ejection fraction from admission to 10 days after infarction, whereas the ejection fraction did not improve in patients with a late peak MB CK. However, the patients with an early peaking MB CK had myocardium in jeopardy as reflected by a higher incidence of ST segment depression and a decrement in the global left ventricular ejection fraction with exercise. The 4 year life table estimate for the rate of recurrent myocardial infarction after hospital discharge was higher in patients with an early peak MB CK (33 versus 22%, p less than 0.05), with an even more striking difference in the 4 year estimate for the rate of fatal recurrent infarction (20 versus 8%, p less than 0.001). The 4 year mortality estimate was markedly higher in hospital survivors with an early peak MB CK than in those with a late peak (47 versus 19%, p less than 0.0001) and, even after adjustment for differences in baseline characteristics, the residual excess mortality in those with an early peak was still significant (p less than 0.02).(ABSTRACT TRUNCATED AT 400 WORDS)

Importance of coronary collateral circulation for kinetics of serum creatine kinase in acute myocardial infarction

The effect of coronary collateral perfusion on the kinetics of creatine kinase (CK) was examined in 32 patients undergoing intracoronary thrombolysis within 6 hours after the onset of a first acute myocardial infarction (AMI). Blood sampling for CK was performed every 2 to 4 hours for a period of 72 hours after AMI. The cumulative CK release was determined using the integrated appearance function curve with the individual disappearance rate. In 19 patients in whom thrombolysis was successful (group A), time to peak CK level was 11 +/- 1 (standard error of the mean) hours after AMI and cumulative CK release was 2,599 +/- 424 U/liter. In 6 patients who had a significant collateral circulation to the infarct-related coronary artery and unsuccessful reperfusion (group B), the time to peak CK was 16 +/- 1 hours (p less than 0.05 compared with group A) and cumulative CK release was 1,897 +/- 478 U/liter (difference not significant compared with group A). In the remaining 7 patients, with neither recanalization nor significant collateral perfusion group C, time to peak CK was 21 +/- 1 hours and significantly (p less than 0.05) longer than groups A and B. Cumulative CK release (2,707 +/- 776 U/liter) was not significantly different from groups A and B. Thus, collateral perfusion is an important determinant of the CK time-activity curve during AMI. Early peaking of CK levels does not reliably identify spontaneous or drug-induced recanalization of the infarct-related coronary artery.