Effects of early intracoronary streptokinase on infarct size estimated from cumulative enzyme release and on enzyme release rate: a randomized trial of 533 patients with acute myocardial infarction

Custodiol-N versus Custodiol: a prospective randomized double-blind multicenter phase III trial in patients undergoing elective coronary bypass surgery

OBJECTIVE

HTK-Solution (Custodiol) is a well-established cardioplegic and organ preservation solution. We currently developed a novel HTK-based solution, Custodiol-N, which includes iron chelators to reduce oxidative injury, as well as L-arginine, to improve endothelial function. In this first in-human study, Custodiol-N compared to Custodiol in patients undergoing elective coronary artery bypass surgery. The aim of this comparison was to evaluate the safety and ability of Custodiol-N to protect cardiac tissue.

METHODS

The study was designed as a prospective randomized double-blind non-inferiority trial. Primary end-point was area under the curve (AUC) of creatine kinase MB (CK-MB) within the first 24 h after surgery. Secondary end-points included peak CK-MB and troponin-T and AUC of troponin-T release, cardiac index, cumulative catecholamine dose, ICU-stay and mortality. All values in the abstract are given as mean ± SD, p < 0.05 was considered statistically significant.

RESULTS

Early termination of the trial was performed per protocol as the primary non-inferiority end-point was reached after inclusion of 101 patients. CK-MB AUC (878 ± 549 vs 779 ± 439 h* U/l, non-inferiority p < 0.001, Custodiol vs Custodiol-N) and troponin-T AUC (12990 ± 8347 vs 13498 ± 6513 h*pg/ml, noninferiority p < 0.001, Custodiol vs Custodiol-N) were similar in both groups. Although the trial was designed for non-inferiority, peak CK-MB (52 ± 40 vs. 42 ± 28 U/l, superiority p < 0.03, Custodiol vs Custodiol-N) was significantly lower in the Custodiol-N group.

CONCLUSION

This study shows that Custodiol-N is safe and provides similar cardiac protection as the established HTK-Custodiol solution. Significantly reduced peak CK-MB levels in the Custodiol-N group in the full analysis set may implicate a beneficial effect on ischaemia/reperfusion injury in the setting of coronary bypass surgery.

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.

Usefulness of peak troponin-T to predict infarct size and long-term outcome in patients with first acute myocardial infarction after primary percutaneous coronary intervention

In acute myocardial infarction cardiac troponin-T (cTnT) is the preferred biomarker to detect myocardial necrosis. Our aim was to investigate the prognostic value of peak plasma cTnT in patients with ST-elevation myocardial infarction treated by primary percutaneous coronary intervention (PCI). Patients were eligible if ST-elevation myocardial infarction symptoms started <9 hours before the primary PCI. During the first 48 hours after primary PCI, cTnT and creatine kinase were measured repeatedly. Main outcome measures were left ventricular ejection fraction assessed by myocardial scintigraphy at 90 days, and clinical outcomes through 1-year follow-up after primary PCI in a dedicated outpatient clinic; 168 consecutive patients (79% men) with first ST-elevation myocardial infarction were studied. Mean age +/- SD was 59 +/- 12 years. Peak cTnT values were reached within 24 hours after primary PCI in all patients. The enzymatic infarct size, measured by cumulative 48-hours creatine kinase release, correlated positively with peak cTnT (r = 0.73, p <0.001). Left ventricular ejection fraction at 3 months was negatively correlated with peak cTnT (r = -0.52, p <0.001). A peak plasma cTnT > or = 6.5 microg/L predicted a left ventricular ejection fraction < or = 40% at follow-up with 86% sensitivity and 74% specificity. Multivariable Cox regression analysis identified peak cTnT as an independent predictor of major adverse cardiac events (hazard ratio 1.07, 95% confidence limits 1.01 to 1.12) and heart failure (hazard ratio 1.12, 95% confidence limits 1.05 to 1.20) during follow-up. In conclusion, peak cTnT after primary PCI for ST-elevation myocardial infarction offers a good estimation of infarct size and is a prognostic indicator in patients with first acute myocardial infarction.

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.

Impact of infarct location on left ventricular ejection fraction after correction for enzymatic infarct size in acute myocardial infarction treated with primary coronary intervention

BACKGROUND

Left ventricular function and infarct size are strong predictors for prognosis after acute myocardial infarction (MI). Anterior MI is associated with greater reduction of left ventricular ejection fraction (LVEF) and worse prognosis. Our objective was to study whether the impact of infarct size on global LVEF is dependent of infarct location.

METHODS

We analyzed 888 patients treated with primary percutaneous coronary intervention for acute MI. Enzymatic infarct size and LVEF within 1 week were measured. In 490 patients (55%), LVEF was measured a second time at 6 months.

RESULTS

Every 1000 U/L of cumulative lactate dehydrogense release corresponded to a decrease of 4.7% (95% CI 4.1-5.3) in LVEF measured within 1 week post MI for left anterior descending coronary artery (LAD)-related infarcts and to a decrease of 2.4% (95% CI 1.7-3.1) in LVEF measured within 1 week post MI for non-LAD-related infarcts (P < .0001). Left ventricular ejection fraction measured 6 months post MI showed a decrease for every 1000 U/L cumulative lactate dehydrogense release of 4.8% (95% CI 4.2-5.3) for LAD and 2.4% (95% CI 1.7-3.1) for non-LAD-related infarcts (P < .0001). Multivariate correction for relevant clinical and angiographic data did not change these results.

CONCLUSION

In patients with a first acute MI treated with primary percutaneous coronary intervention, LAD-related infarcts show for a similar amount of myocardial necrosis as determined by enzymatic infarct size, a lower residual LVEF when compared with non-LAD-related infarcts.

Thrombus Aspiration during Percutaneous coronary intervention in Acute myocardial infarction Study (TAPAS)--study design

BACKGROUND AND OBJECTIVE

Embolization of atherothrombotic material is common during percutaneous coronary intervention (PCI) in acute myocardial infarction (MI). This may lead to distal vessel occlusion resulting in impaired myocardial perfusion, which is associated with larger infarct size and increased mortality. Adjunctive devices for PCI to protect the microcirculation have been developed. We intend to determine whether aspiration of thrombotic material before stent implantation of the infarct-related coronary artery results in improved myocardial perfusion compared with conventional primary PCI.

STUDY DESIGN

TAPAS is a single-center, prospective, randomized trial with a planned inclusion of 1080 patients with ST-elevation MI. Patients are assigned to treatment with thrombus aspiration with the 6F Export Aspiration Catheter (Medtronic Corporation, Santa Rosa, Calif) or to balloon angioplasty before stent implantation in the infarct-related artery. All patients will be treated medically according to current international guidelines including glycoprotein IIb/IIIa inhibitors before PCI. Randomization will be performed before coronary angiography. The primary end point is angiographic myocardial blush grade of <2. Secondary end points are enzymatic infarct size, ST-segment elevation resolution and persistent ST-segment elevation, postprocedural distal embolization, and Major Adverse Cardiac Events at 30 days and 1 year.

IMPLICATIONS

If thrombus aspiration significantly improves myocardial perfusion, it will lend support to the use of this treatment as part of the standard approach in patients with acute MI.

Effect of pexelizumab, an anti-C5 complement antibody, as adjunctive therapy to fibrinolysis in acute myocardial infarction: the COMPlement inhibition in myocardial infarction treated with thromboLYtics (COMPLY) trial

BACKGROUND

Complement activation mediates myocardial damage that occurs during ischemia and reperfusion through multiple pathways. We performed 2 separate, parallel, double-blind, placebo-controlled trials to determine the effects of pexelizumab (a novel C5 complement monoclonal antibody fragment) on infarct size in patients receiving reperfusion therapy: COMPlement inhibition in myocardial infarction treated with thromboLYtics (COMPLY) and COMplement inhibition in Myocardial infarction treated with Angioplasty (COMMA). The COMPLY trial is reported here.

METHODS AND RESULTS

Overall, 943 patients with acute ST-segment elevation myocardial infarction (MI) (20% with isolated inferior MI) receiving fibrinolysis were randomly assigned <6 hours after symptom onset to placebo, pexelizumab 2.0-mg/kg bolus, or pexelizumab 2.0-mg/kg bolus plus 0.05 mg/kg per h for 20 hours. Infarct size determined by creatine kinase-MB area under the curve was the primary analysis, which included patients who received at least some study drug and fibrinolysis (n=920). The median infarct size did not differ by treatment (placebo, 5230; bolus, 4952; bolus plus infusion, 5557 [ng/mL] x h; bolus versus placebo, P=0.85; bolus plus infusion versus placebo, P=0.81), nor did the 90-day composite incidence of death, new or worsening congestive heart failure, shock, or stroke (placebo, 18.6%; bolus, 18.4%; bolus plus infusion, 19.7%). Pexelizumab inhibited complement for 4 hours with bolus-only dosing and for 20 to 24 hours with bolus-plus-infusion dosing, with no increase in infections.

CONCLUSIONS

When used adjunctively with fibrinolysis, pexelizumab blocked complement activity but reduced neither infarct size by creatine kinase-MB assessment nor adverse clinical outcomes.

Reperfusion arrhythmias during coronary angioplasty for acute myocardial infarction predict ST-segment resolution

BACKGROUND

Despite early recanalization of an occluded infarct-related artery, myocardial reperfusion may remain impaired due to microvascular injury. Reperfusion arrhythmias may indicate successful microvascular reperfusion.

METHODS

Microvascular reperfusion was assessed prospectively in 42 consecutive patients with ST-segment elevation acute myocardial infarction (AMI) by evaluation of the resolution of ST-segment elevation (<50% of initial level) immediately after successful coronary angioplasty. Patients were divided into two groups: those with ST resolution (n=24) and those without ST resolution (n=18). The presence of reperfusion arrhythmias immediately after recanalization was recorded.

RESULTS

Patients with ST resolution were younger (54+/-12 years compared with 64+/-17 years, P=0.04), their pain-to-recanalization time was shorter (195+/-87 min compared with 294+/-179 min, P=0.05), they were less often diabetic (13% compared with 24%, P=0.05) and were more often given IIb/IIIa inhibitors (58% compared with 22%, P=0.02). Reperfusion arrhythmias were observed in 15 out of 24 patients with ST resolution (62%) but in only one out of 18 without ST resolution (5%) (P<0.01). Reperfusion arrhythmias included accelerated idioventricular rhythm, 13 (81%); multifocal ventricular premature beats, two (13%); and ventricular tachycardia, one (6%). The sensitivity and specificity of reperfusion arrhythmias for ST resolution were 62 and 95%, respectively. In a logistic regression model including age, time to treatment, diabetes, use of IIb/IIIa inhibitors and reperfusion arrhythmias, only the latter was found to be an independent predictor of ST resolution (P<0.01).

CONCLUSION

Reperfusion arrhythmias following coronary angioplasty for AMI are a highly specific marker for ST resolution and may indicate successful microvascular reperfusion.

Troponin I concentrations following primary percutaneous coronary intervention predict large infarct size and left ventricular dysfunction in patients with ST-segment elevation acute myocardial infarction

The aim of this study was to investigate the ability of troponin I (cTnI) levels to predict myocardial infarction size in patients with ST-segment elevation acute myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI). In 87 patients with STEMI undergoing primary PCI, serial plasma concentrations of cTnI and alpha-hydroxybutyrate deshydrogenase (HBDH) were measured before PCI and over the following 72 h. Enzymatic infarct size was estimated by the cumulative release of HBDH during the 72 h following PCI (QHBDH72). Delayed radionuclide left ventricular ejection fraction (LVEF) was measured in 63 patients. While cTnI concentrations at admission did not correlate with QHBDH72 or with LVEF, from the 3rd to the 72nd h following PCI, they did correlated with QHBDH72 (P<0.001; R: 0.76-0.86) and with LVEF (P<0.001; R: -0.42 to -0.50). Receiver-operator characteristic (ROC) curve analysis showed that admission concentrations of cTnI could not predict either a large infarct size (i.e., QHBDH72>10 g-eq l(-1)) or a low LVEF (i.e., LVEF<40%). However, 6 h and up until 72 h after PTCA, cTnI concentrations were predictive of large enzymatic infarct size (sensitivity: 91 and 95%, specificity: 90 and 87%, respectively) and of LVEF under 40% (sensitivity: 75 and 77%, specificity: 90 and 78%, respectively). Thus, our study suggests that in contrast with admission cTnI concentration, cTnI levels following primary PCI represent a reliable tool for predicting large enzymatic infarct size and may help in selecting patients with a high risk of low LVEF at 1 month.

Influence of prehospital administration of aspirin and heparin on initial patency of the infarct-related artery in patients with acute ST elevation myocardial infarction

OBJECTIVES

The aim of this study was to investigate the influence of prehospital administration of aspirin and heparin on the initial patency of the infarct-related artery (IRA) in patients with acute myocardial infarction (MI).

BACKGROUND

Prehospital diagnosis of acute MI facilitates early pharmacologic intervention on the way to the catheterization laboratory for primary angioplasty.

METHODS

We studied the angiographic data and 30-day clinical outcome of 1,702 patients treated with primary angioplasty; 860 received aspirin and heparin before transportation to our hospital and 842 received aspirin and heparin in our hospital.

RESULTS

The Thrombolysis In Myocardial Infarction (TIMI) 2 or 3 flow in the IRA was higher in the prehospital treated group (31% vs. 20%, relative risk 0.65, 95% confidence interval 0.55 to 0.78, p < 0.001). Patients with TIMI 2 or 3 flow on the initial angiogram had a higher angioplasty success rate (94% vs. 89%, p < 0.001), a smaller enzymatic infarct size, a higher left ventricular ejection fraction and a lower 30-day mortality (1.6% vs. 3.4%, p = 0.04).

CONCLUSIONS

Prehospital administration of aspirin and heparin results in a higher initial patency of the IRA in patients with acute MI.

Failed reperfusion after thrombolytic therapy: recognition and management

BACKGROUND

Failed reperfusion after thrombolysis occurs in as many as 30% of patients with acute myocardial infarction (MI). Furthermore, some patients have incomplete tissue perfusion despite reperfusion of the infarct-related artery. Close assessment of the efficacy of thrombolytic administration in people with evolving acute MI is necessary, particularly with regard to myocardial perfusion status, because some patients may benefit from incremental pharmacologic or invasive reperfusion strategies.

PURPOSE AND METHOD

This article reviews a number of strategies to assess infarct-related artery patency and myocardial tissue perfusion. These include coronary angiography, continuous ST-segment monitoring, serial electrocardiography, obtaining serial serum biochemical markers of myocardial necrosis, monitoring for reperfusion arrhythmias, and assessment of changes in chest pain intensity.

CONCLUSION

The early detection of failed reperfusion is critical if incremental strategies to enhance myocardial salvage are to be considered. Continuous ST-segment monitoring is a relatively inexpensive, reliable, and accurate tool for assessing real-time myocardial perfusion.

A comparison of electrocardiographic changes during reperfusion of acute myocardial infarction by thrombolysis or percutaneous transluminal coronary angioplasty

BACKGROUND

Different electrocardiographic changes have been described during thrombolytic therapy for acute myocardial infarction to indicate successful reperfusion. The occluded coronary artery also can be reopened by percutaneous transluminal coronary angioplasty (PTCA). This study was performed to compare electrocardiographic changes during primary or rescue PTCA and thrombolytic therapy. The electrocardiographic changes were studied directly at the moment of reperfusion during PTCA.

METHODS AND RESULTS

Continuous 12-lead electrocardiographic monitoring was performed in 110 patients with acute myocardial infarction undergoing a reperfusion intervention (thrombolytic therapy or primary or rescue PTCA) to assess electrocardiographic changes during reperfusion. Patency and Thrombolysis In Myocardial Infarction flow in the infarct-related artery were assessed by coronary angiography. During reperfusion of the infarct-related coronary artery, early signs of reperfusion were an increase of ST-segment deviation (30%), ST-segment normalization (70%), and terminal T-wave inversion (60%); only 11% of patients showed no ST-segment changes. Thrombolytic therapy was significantly more often accompanied by a transient increase in ST-segment deviation compared with primary PTCA. Accelerated idioventricular rhythm was documented in 51%, an increase in the number of ventricular premature complexes in 42%, nonsustained ventricular tachycardia in 7%, and bradycardia in 18% of all patients.

CONCLUSIONS

This study confirms the occurrence of specific electrocardiographic changes at the time of reperfusion. The pattern of ST-segment change upon reperfusion relates to the type of treatment. Awareness of electrocardiographic changes at the moment of reperfusion will help to select patients for rescue PTCA and can be used to assess the effect of future pharmacologic interventions to limit reperfusion damage.

High dose heparin as pretreatment for primary angioplasty in acute myocardial infarction: the Heparin in Early Patency (HEAP) randomized trial

OBJECTIVES

In the Heparin in Early Patency (HEAP) pilot study a beneficial effect of high-dose heparin on early patency in acute myocardial infarction (MI) was observed in a matched-control study.

BACKGROUND

High dose bolus intravenous injection of heparin may achieve lysis of coronary thrombi and could enhance early patency of the infarct related vessel in patients with MI scheduled for primary angioplasty.

METHODS

Before primary angioplasty, 584 patients with MI entered an open randomized trial of high dose (300 IU/kg) or low dose (0 or 5,000 IU) heparin. Of the 584 patients, 299 were randomized to high dose and 285 patients to low dose heparin.

RESULTS

Thrombolysis In Myocardial Infarction (TIMI) flow grade 2 or 3 was observed before primary angioplasty in 65 patients (22%) in the high dose group and 60 patients (21%) in the low dose heparin group (p > 0.1), whereas TIMI flow grade 3 was observed in 38 (13%) and 24 patients (9%), respectively (p = 0.11). There were no differences in the clinical end points between the two groups. There were no hemorrhagic strokes, while 10% of the patients in the high dose group required blood transfusion versus 6% in the low dose/no heparin group (p = 0.07). No subsets of patients showed beneficial effects of high dose heparin, such as patients with longer delay between heparin administration and diagnostic angiogram or patients with short delay between symptom onset and admission.

CONCLUSIONS

There is no benefit of high dose bolus heparin on early patency compared with no or low dose heparin.

Influence of treatment delay on infarct size and clinical outcome in patients with acute myocardial infarction treated with primary angioplasty

OBJECTIVES

The purpose of this analysis was to determine the influence of an additional treatment delay inherent in transfer to an angioplasty center for primary angioplasty of patients with acute myocardial infarction who are first admitted to hospitals without angioplasty facilities.

BACKGROUND

Several randomized trials have demonstrated the benefits of primary angioplasty in acute myocardial infarction. In recent years, increasing numbers of patients with myocardial infarction, initially admitted to hospitals without angioplasty facilities are transported to our hospital for primary angioplasty. However, the additional delay due to the transport may have a deleterious effect on infarct size and clinical outcome.

METHODS

In a three-year period (December 1993 to November 1996), 207 consecutive patients who were transferred for primary angioplasty were analyzed in a matched comparison with non-transferred patients. Matching criteria were age, sex, infarct location, presentation delay and Killip class.

RESULTS

Patients who were transferred had an additional median delay of 43 min. This resulted in a more extensive enzymatic infarct size and a lower ejection fraction measured at 6 months. The rate of angioplasty success defined as TIMI grade 3 flow, and the 6-month mortality rate (7%) were comparable in both groups.

CONCLUSIONS

The additional delay had a deleterious effect on myocardial salvage, reflected by a larger infarct size and a lower left ventricular function. However, the patency rate and 6-month clinical outcome were not affected by this delay.

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.

Clinical value of 12-lead electrocardiogram after successful reperfusion therapy for acute myocardial infarction. Zwolle Myocardial infarction Study Group

BACKGROUND

A simple clinical method to stratify risk for patients who have had successful reperfusion therapy after myocardial infarction is attractive since it facilitates the tailoring of therapy.

METHODS

We investigated the clinical value of the 12-lead electrocardiogram (ECG), in 403 patients after successful reperfusion therapy by primary coronary angioplasty, in relation to infarct size measured by enzyme activity, left-ventricular function, and clinical outcome. ECGs were analysed to find the extent of the ST-segment-elevation resolution 1 h after reperfusion therapy.

FINDINGS

A normalised ST segment was seen in 51% of patients, a partly normalised ST segment in 34%, and 15% had no ST-segment-elevation resolution. Enzymatic infarct size and ejection fraction were related to the extent of the early resolution of the ST segment. The relative risk of death among patients with no resolution compared with patients with a normalised ST segment was 8.7 (95% CI 3.7-20.1), and that among patients with partial resolution compared with patients with a normalised ST segment was 3.6 (1.6-8.3).

INTERPRETATION

Our findings suggest that ECG patterns reflect the effectiveness of myocardial reperfusion. Patients for whom reperfusion therapy by primary angioplasty was successful and who had normalised ST segments had limited damage to the myocardium and an excellent outlook during follow-up. Patients with persistent ST elevation after reperfusion therapy may need additional interventions since they have more extensive myocardial damage and have a higher mortality rate.

Regional myocardial shape alterations in patients with anterior myocardial infarction

OBJECTIVE

To assess the impact of regional left ventricular curvature in patients with an acute anterior myocardial infarction on ventricular volume.

METHODS

Left ventricular curvature was calculated at 100 points from apical four chamber echocardiograms of 68 patients with an acute anterior wall infarction. Curvature at any point of the contour was defined as the reciprocal of the radius of the circle that intersects that point tangentially and was independent of volume and geometric assumptions. Curvature, volume and shape of the patient group was compared with these measurements in 20 normal volunteers.

RESULTS

Diastolic curvature differed at the borderzone of the infarct and the apical area. In the basal septal area (point 9-18) mean curvature was lower in the patient group (0.1 +/- 2.7 versus 2.1 +/- 0.7; p < 0.0001) as compared to the normal individuals. In the mid-septal area (point 22 to 27), mean curvature was more concave (-0.1 +/- 2.6) in the patient group corresponding to in the normal population (-0.4 +/- 1.3) p < 0.005. In the apex point 52 and 53 diverged with a curvature of 9.9 +/- 1.9 in patients versus 9.4 +/- 2.9 p < 0.005 in normal individuals. Systolic curvature diverged at the basal septum (point 1-4) with a mean curvature of 1.4 +/- 1.1 in patients compared to 3.5 +/- 2.5 in normal individuals p < 0.01. Curvature differed also in the mid-septal region (point 9-29) with a curvature of -1.7 +/- 1.2 in patients versus 0.4 +/- 0.9 (p < 0.01) in normal individuals and in the apical septum (point 48-52) with a curvature of 16.6 +/- 5.2 in patients and 13.9 +/- 2.6 (p < 0.0001) in healthy individuals Separation of patients with the greatest curvature alteration to those with minor curvature change revealed, that baseline curvature analysis can discriminate patients at risk for left ventricular remodelling.

CONCLUSION

Regional curvature analysis correctly identifies the geometric changes induced by myocardial infarction. Apical systolic curvature can distinguish those patients that are at risk for left ventricular remodelling from those who are not at risk.

Electrocardiographic diagnosis of reperfusion during thrombolytic therapy in acute myocardial infarction

Continuous 12-lead electrocardiographic monitoring was performed in 61 patients receiving thrombolytic therapy for an acute myocardial infarction. Coronary angiography within 90 minutes revealed a patent vessel (Thrombolysis in Myocardial Infarction [TIMI] trial 2 or 3) in 44 patients. Early signs of reperfusion were ST-segment normalization (likelihood ratio 16.0), development of terminal T-wave inversion (likelihood ratio 10.6), accelerated idioventricular rhythm (likelihood ratio 6.0), and a twofold increase in ventricular premature complexes (likelihood ratio 2.5). Relief of chest pain after 60 minutes was reported by 96%. During reperfusion of the infarct-related vessel, an increase in ST-segment deviation was recorded in 61% of the patients, whereas 69% had an increase in chest pain preceding the eventual decline.

Early identification of patients at risk for significant left ventricular dilation one year after myocardial infarction

We prospectively investigated criteria to identify patients in the early phase of acute myocardial infarction at risk for significant left ventricular (LV) dilation 1 year after myocardial infarction. In 54 patients receiving thrombolysis within 4 hours after onset of symptoms, the end-diastolic volume index (EDVI) and the end-systolic volume index were assessed by two-dimensional echocardiography initially (within 23 +/- 21 hours) and 1 year after myocardial infarction. After 1 year, LV dilation occurred in 51 patients (94%) and was significant (> mean normal value + 2 SDs) in 14 patients (26%). Significant univariate predictors (p < 0.05) for LV dilation were age, anterior myocardial infarction, initial EDVI and end-systolic volume index, enzymatic infarct size, LV end-diastolic pressure, and mitral regurgitation. No other variables obtained from clinical information, two-dimensional echocardiography, or angiography, including residual coronary perfusion or stenosis, had predictive value. The optimal multivariate predictive model was the combination of the initial EDVI and the enzymatic infarct size, which correctly predicted significant LV dilation in 12 of 14 patients and falsely in eight of 39 patients (sensitivity 86%; specificity 79%). Patients at risk for significant LV dilation 1 year after myocardial infarction were identified adequately 3 days after myocardial infarction by the combination of the initial echocardiographic assessment of EDVI and the enzymatic infarct size. Thus a simple method could facilitate the selection of patients for intervention after acute myocardial infarction.

Limitation of infarct size and preservation of left ventricular function after primary coronary angioplasty compared with intravenous streptokinase in acute myocardial infarction

BACKGROUND

Early and effective flow through the infarct-related vessel is probably of paramount importance for limitation of infarct size and preservation of left ventricular function in patients with acute myocardial infarction. Primary coronary angioplasty may offer advantages in these respects compared with thrombolytic therapy. The purpose of the present study was to assess the effects on estimated enzymatic infarct size and left ventricular function in patients with acute myocardial infarction randomly assigned to undergo primary angioplasty or to receive intravenous streptokinase.

METHODS AND RESULTS

We evaluated 301 patients with signs of acute myocardial infarction and without contraindications for thrombolysis who presented within 6 hours after onset of symptoms or between 6 and 24 hours if there was evidence of ongoing ischemia. One hundred fifty-two patients were randomly assigned to undergo primary angioplasty, and 149 patients were assigned to receive treatment with streptokinase (1.5 million U i.v.). Infarct size was estimated from enzyme release. Global left ventricular ejection fraction and regional wall motion, if possible in combination with exercise testing, were evaluated by radionuclide ventriculography before discharge. Thrombolysis in Myocardial Infarction (TIMI) flow grade 3 through the infarct-related vessel within 120 minutes after admission was achieved in 92% of all patients assigned to receive primary angioplasty therapy. Myocardial infarct size was 23% smaller in the angioplasty group compared with patients assigned to receive streptokinase (1003 +/- 784 versus 1310 +/- 1198 U/L, P = .012). Global left ventricular ejection fraction (50 +/- 9% versus 45 +/- 11%, P < .001) and regional wall motion in the infarct-related zones (42 +/- 14% versus 34 +/- 13%, P < .001) were better in the angioplasty group, which could mainly be contributed to myocardial salvage in the infarct-related areas. The observed differences were more pronounced in patients with an anterior wall myocardial infarction, although patients with a nonanterior infarct location also showed a beneficial effect of primary coronary angioplasty on left ventricular function compared with streptokinase therapy. Furthermore, the observed differences appeared to be more pronounced in patients presenting relatively early (within 2 hours) after onset of symptoms.

CONCLUSIONS

In patients with acute myocardial infarction, primary angioplasty results in a smaller infarct size and a better preserved myocardial function compared with patients randomized to receive treatment with intravenous streptokinase. This is probably due to early and optimal blood flow through the infarct-related vessel, as can be accomplished in a very high percentage of patients undergoing primary coronary angioplasty.

Enzymes as agents for the treatment of disease

The replacement of genetically deficient enzymes in patients with inherited metabolic disorders by infusion of purified enzymes or by organ transplantation has had very limited success, although good results with bone marrow transplantation have been obtained in some patients with mucopolysaccharidosis, Gaucher disease and inherited immunodeficiency diseases. Genetic engineering of the patient's lymphocytes may ultimately render these approaches redundant, at least for some of these diseases. Treatment of chronic pancreatic insufficiency and of disaccharidase deficiency with oral enzymes can be very effective; therapy can be monitored in the latter by measuring the breath hydrogen excretion and in the former by a range of tests of which stool chymotrypsin assay is the most convenient. Treatment of acute myocardial infarction by intracoronary perfusion of thrombolytic enzymes can improve both cardiac function and long-term survival if given early enough. Successful reperfusion can be identified by changes in the kinetics of serum enzyme release and clearance, especially for the isoenzymes and isoforms of creatine kinase. In cancer chemotherapy, L-asparaginase has long been a useful adjunct in the treatment of acute lymphoblastic leukemia, but recent experience suggests a role in acute nonlymphoblastic leukemia as well.

Are enzymatic tests good indicators of coronary reperfusion?

OBJECTIVE

To assess the accuracy of four enzymatic tests, including early release rates of creatine kinase and alpha-hydroxybutyrate dehydrogenase, in assessing coronary reperfusion after thrombolytic therapy.

DESIGN

A prospective clinical trial identifying patients with a successful thrombolytic treatment.

PATIENTS

Eighty nine patients with acute myocardial infarction were studied. Arteriography showed a closed infarct related artery in all of them. Reperfusion due to thrombolysis occurred in 74 patients and there was no reperfusion in 15 patients.

RESULTS

The 74 patients showing coronary reperfusion had a significantly shorter time to peak creatine kinase activity, higher early release rates for creatine kinase and alpha-hydroxybutyrate dehydrogenase, and a more rapid release of alpha-hydroxybutyrate dehydrogenase (ratio of cumulative release of alpha-hydroxybutyrate dehydrogenase during the first 24 hours to that 72 hours after infarction). All these differences were statistically significant (p less than 0.001). Optimum cut off levels were determined with decision level plots and the accuracy of the four enzymatic tests was calculated. Accuracy was low for all four tests (73%, 70%, 70%, and 82%).

CONCLUSION

None of the four enzymatic tests accurately predicted the perfusion state of the infarct related coronary artery after thrombolysis. These tests cannot be used reliably in routine clinical practice as non-angiographic markers of coronary reperfusion.

Angiographically assessed coronary arterial patency and reocclusion in patients with acute myocardial infarction treated with anistreplase: results of the anistreplase reocclusion multicenter study (ARMS)

In this open multicenter study, 156 patients with acute myocardial infarction received 30 U of anistreplase intravenously over 5 minutes within 4 hours of the onset of chest pain. The patency of the infarct-related vessel was determined by coronary angiography 90 minutes after anistreplase treatment, and also 24 hours after treatment, in patients with a patent infarct-related vessel at 90 minutes, to assess the reocclusion rate. The investigators categorized the infarct-related vessel as patent or occluded, and 2 independent cardiologists graded the infarct-related vessel according to the Thrombolysis in Myocardial Infarction (TIMI) perfusion criteria. At the 90-minute assessment, 106 of 145 evaluable patients (73%) had patent infarct-related vessels, and 39 of 145 (27%) had occluded infarct-related vessels. Of the 139 independently assessed patients, 98 (71%) had TIMI grades 2 or 3 and 41 (29%) had TIMI grades 0 or 1. At the 24-hour assessment, 98 of 102 patients (96%) had a patent infarct-related vessel, and reocclusion had occurred in 4 of 102 patients (4%). Of the 94 independently assessed patients 90 (96%) had TIMI grades 2 or 3, and 4 (4%) had TIMI grades 0 or 1. The reliability of noninvasive parameters as indicators of achieved patency of the infarct-related vessel was estimated by means of correlation with patency assessed by coronary angiography. A significant correlation of 0.62 was found. The patency rate of 71 to 73% after use of anistreplase in patients with acute myocardial infarction corresponds with findings in earlier studies. The low reocclusion rate of 4% after use of anistreplase probably reflects the prolonged action of anistreplase.

Effects of early intervention with low-dose aspirin (100 mg) on infarct size, reinfarction and mortality in anterior wall acute myocardial infarction

Recently, it was shown that aspirin given early in acute myocardial infarction (AMI) improves hospital survival, but the mechanisms involved are unclear. In a prospective, randomized placebo-controlled trial, the influence of early intervention with low-dose aspirin (100 mg/day) on infarct size and clinical outcome was studied in 100 consecutive patients with first anterior wall AMI. Infarct size was calculated by cumulative lactate dehydrogenase release in the first 72 hours after admission and was found to be (mean +/- standard deviation) 1,431 +/- 782 U/liter in the aspirin group (n = 50) and 1,592 +/- 1,082 U/liter in the placebo group (n = 50, p = 0.35). The study medication was given for 3 months, during which mortality was 10 (20%) in the aspirin patients and 12 (24%) in the placebo patients (p = 0.65). However, reinfarction occurred in 2 patients (4%) in the aspirin group and in 9 (18%) in the placebo group (p less than 0.03). Early intervention with low-dose aspirin showed, in comparison to placebo, a 10% decrease of infarct size, but this difference was not statistically significant. However, early low-dose aspirin effectively decreased the risk of reinfarction. Therefore, the favor able results of early aspirin on mortality in acute myocardial infarction are probably due more to prevention of reinfarction than to decrease of infarct size.

Enhanced thrombolytic efficacy and reduction of infarct size by simultaneous infusion of streptokinase and heparin

Because paradoxical increase in thrombin activity was reported after the administration of streptokinase in patients with acute myocardial infarction the velocity of reperfusion and degree of myocardial damage were studied when heparin was infused during rather than after streptokinase infusion. Thirty seven consecutive patients with acute myocardial infarction were randomised to receive intravenous heparin during (group 1, n = 18) or after (group 2, n = 19) streptokinase (1.5 megaunits over 60 minutes). Markers of reperfusion were monitored every 15 minutes for 3 hours. The serum concentration of creatine kinase was measured every 2 hours. The two groups were similar in terms of age and sex distribution, infarct site, time to treatment, and baseline myocardial ischaemia. Patients in group 1 had a significantly shorter mean (SD) reperfusion time (57 (35) minutes v 101 (47)). From 60 to 120 minutes after randomisation there were significant differences in ST segment elevation between the groups. Serum creatine kinase MB peaked earlier (8 (2) hours) in group 1 than in group 2 (10 (4) hours). The peak concentration was significantly lower in group 1 (87 (47) mU/ml) than in group 2 (134 (96) mU/ml) and infarcts were smaller (25.2 (9.8) gram equivalents/m2) in group 1 than in group 2 (35.1 (10.2) gram equivalents/m2). Simultaneous infusion of heparin and streptokinase speeds up the appearance of signs of reperfusion and reduces infarct size.

Diagnostic significance of gadolinium-DTPA (diethylenetriamine penta-acetic acid) enhanced magnetic resonance imaging in thrombolytic treatment for acute myocardial infarction: its potential in assessing reperfusion

The diagnostic value of gadolinium-DTPA (diethylenetriamine penta-acetic acid) enhanced magnetic resonance imaging in patients treated by thrombolysis for acute myocardial infarction was assessed in 27 consecutive patients who had a first acute myocardial infarction (14 anterior, 13 inferior) and who underwent thrombolytic treatment and coronary arteriography within 4 hours of the onset of symptoms. Magnetic resonance imaging was performed 93 hours (range 15-241) after the onset of symptoms. A Philips Gyroscan (0.5 T) was used, and spin echo measurements (echo time 30 ms) were made before and 20 minutes after intravenous injection of 0.1 mmol/kg gadolinium-DTPA. In all patients contrast enhancement of the infarcted areas was seen after Gd-DTPA. The signal intensities of the infarcted and normal values were used to calculate the intensity ratios. Mean (SD) intensity ratios after Gd-DTPA were significantly increased (1.15 (0.17) v 1.52 (0.29). Intensity ratios were higher in the 17 patients who underwent magnetic resonance imaging more than 72 hours after the onset of symptoms than in the 10 who underwent magnetic resonance imaging earlier, the difference being significantly greater after administration of Gd-DTPA (1.38 (0.12) v 1.61 (0.34). When patients were classified according to the site and size of the infarcted areas, or to reperfusion (n = 19) versus non-reperfusion (n = 8), the intensity ratios both before and after Gd-DTPA did not show significant differences. Magnetic resonance imaging with Gd-DTPA improved the identification of acutely infarcted areas, but with current techniques did not identify patients in whom thrombolytic treatment was successful.

Serial quantitative planar technetium-99m isonitrile imaging in acute myocardial infarction: efficacy for noninvasive assessment of thrombolytic therapy

Technetium-99m isonitrile is a new myocardial perfusion imaging agent that accumulates according to the distribution of myocardial blood flow. However, unlike thallium-201, it does not redistribute over time. This imaging agent was used with serial quantitative planar imaging to assess the initial risk area of infarction, its change over time and the relation to infarct-related artery patency in 30 patients with a first acute myocardial infarction. Twenty-three of 30 patients were treated with recombinant tissue-type plasminogen activator (rt-PA) within 4 h after the onset of chest pain. Seven patients were treated in the conventional manner without thrombolytic therapy. Technetium-99m isonitrile was injected before or at the initiation of thrombolytic therapy, and imaging was performed several hours later. These initial images demonstrated the area at risk. Repeat imaging was performed 18 to 48 h later and at 6 to 14 days after the onset of myocardial infarction to visualize the ultimate extent of infarction. The initial area at risk varied greatly (range defect integral 2 to 61) both in patients treated with rt-PA and in those who received conventional treatment. For the total group, the initial imaging defect decreased in size in 20 patients and was unchanged or larger in 10 patients. Patients with a patent infarct-related artery had a significantly greater decrease in defect size than did patients with persistent coronary occlusion (-51 +/- 38% versus -1 +/- 26%, p = 0.0001). All patients with a decrease in defect size greater than 30% had a patent infarct-related artery. In 12 patients who also had predischarge quantitative exercise thallium-201 imaging, good agreement existed between the extent and severity of myocardial perfusion defect on the last technetium-99m isonitrile study before discharge and that noted on delayed thallium-201 imaging. It is concluded that serial planar technetium-99m isonitrile myocardial imaging in patients with acute myocardial infarction undergoing thrombolytic therapy offers a new quantitative noninvasive approach for assessment of the initial risk zone as well as the success of reperfusion.

Right ventricular infarction: larger enzyme release with posterior than with anterior involvement

To evaluate whether the right ventricle releases significant amount of cardiac enzymes during myocardial infarction, a clinicopathologic study of 50 patients with 60 infarcts was performed. Myocardial infarct size was determined at autopsy and compared with the corresponding peak serum lactate dehydrogenase and aspartate aminotransferase. Anterior and posterior infarcts had similar anatomic size, peak enzyme values, and coefficients of correlation (r = 0.86-0.88 versus r = 0.82-0.84 for lactate dehydrogenase). However, by disregarding the right ventricular infarct component considering the left ventricular infarction only, the coefficient of correlation between infarct size and peak serum lactate dehydrogenase decreased from r = 0.84 to r = 0.59 (P = 0.09), in 14 posterior infarcts while no change was observed in 24 anterior infarcts (r = 0.88). This indicates, that a considerable amount of enzymes released during posterior infarction originated from the right ventricle which was not the case for anterior infarction.

Reperfusion therapy in inferior myocardial infarction

This review summarizes the multicenter trial results of reperfusion therapy for treatment of inferior myocardial infarction. Therapy with intracoronary streptokinase or intravenous recombinant tissue plasminogen activator (rt-PA) produced higher patency rates than did intravenous streptokinase. Reocclusion was more common when the right coronary artery was the infarct-related artery, irrespective of treatment strategy. Left ventricular ejection fraction was improved compared with that in control patients, especially when the time from symptom onset was brief or when patency rates were high. Enzymatic infarct size was reduced in treated patients. A trend toward mortality reduction in treated patients was found in four studies and was statistically significant in the Second International Study of Infarct Survival (ISIS-2) trial. Precordial ST segment depression in inferior myocardial infarction is associated with values for enzyme release, left ventricular ejection fraction and mortality similar to those in anterior infarction. Patients with inferior infarction who present within 6 h of symptom onset with precordial ST segment depression should be considered candidates for intravenous thrombolytic therapy with rt-PA; immediate cardiac catheterization and possible coronary angioplasty should be limited to those who are in hemodynamically unstable condition. Patients without precordial ST segment depression who present within 3 h of symptom onset and who do not have risk factors for bleeding should also be candidates for intravenous rt-PA therapy. The prognosis of other patients with inferior myocardial infarction is so good that the issue of thrombolytic therapy remains unsettled.

Cost benefit analysis of early thrombolytic treatment with intracoronary streptokinase. Twelve month follow up report of the randomised multicentre trial conducted by the Interuniversity Cardiology Institute of The Netherlands

The costs and benefits of early thrombolytic treatment with intracoronary streptokinase in acute myocardial infarction were compared in a randomised trial. All hospital admissions were recorded and the functional class was assessed at visits to the outpatient clinic during a 12 month follow up of 269 patients allocated to thrombolytic treatment and of 264 allocated to conventional treatment. Mean survival during the first year was calculated for patients with inferior and with anterior infarction and adjusted for impaired quality of life in cases where there were symptoms or hospital admission. In patients with inferior infarction mean survival was 337 days (out of a total follow up of 365 days) for patients allocated to thrombolytic treatment and 327 days for controls. Quality adjusted survival was seven days longer in the thrombolysis group (307 vs 300 days in controls). In patients with anterior infarction mean survival was significantly longer (35 days) in the thrombolysis group than in the control group as was quality adjusted survival (38 days) (304 vs 266 days in controls). The gain in life expectancy with thrombolytic treatment was 0.7 years for patients with inferior infarction, 2.4 years for patients with anterior infarction, and 3.6 years for the subset of patients with large anterior infarction who were admitted within two hours of the onset of symptoms. The costs of medical treatment, including medication, hospital stay, cardiac catheterisation, coronary angioplasty, and bypass surgery, in the first year follow up were higher inpatients allocated to thrombolytic treatment (an additional cost ofDfl 7000 in inferior and Dfl 9000in anterior infarction (1 pounds sterling approximately Dfl 3.3.)) than in conventionally treated patients. The additional costs per year of life gained were Dfl 10 000 in inferior infarction, Dfl 3 800 in anterior infarction, and only Dfl 1 900 in patients with large anterior infarction admitted within two hours of onset of symptoms. Intracoronary thrombolysis can be recommended as a cost effective treatment in patients with extensive anteroseptal infarction.

The size of infarction as judged enzymatically in 1974 patients with acute myocardial infarction. Relation with symptomatology, infarct localization and type of infarction

A common data base of six coronary care units containing personal and clinical data of 17462 patients was used to investigate the relation between clinical symptoms of patients with acute myocardial infarction and size of infarction. In 1974 of the 5110 patients, in whom a final diagnosis of infarction was made, size of infarction was determined according to serially measured levels of serum alpha-hydroxybutyrate dehydrogenase. The episode of infarction was the first in 1396 patients, was recurrent in 497, and undetermined in 81 patients. We calculated the size factor (defined as the mean size of infarction of patients with a particular symptom divided by the mean size of infarction of patients without that symptom) to evaluate the role of the size of infarction to manifestation of certain clinical symptoms. Bradycardia, shock and right-sided failure when noted on admission to the coronary care unit, had factors for size of infarction significantly greater than 1.0 (1.15, 1.79 and 1.30, respectively) in patients suffering an initial infarction, but not significantly different from 1.0 in patients with recurrent infarction. The occurrence of primary and secondary ventricular tachycardia and/or fibrillation, left heart failure (Killip class II-IV), symptomatic supraventricular tachycardia, high-degree atrioventricular blocks, ruptures and death in the coronary care unit was associated with factors significantly greater than 1.0 in those patients having both initial and recurrent infarctions. The size of infarction as judged enzymatically was significantly larger in patients with anterior than inferior and lateral infarction. The size of infarctions without Q waves was judged to be generally 35% smaller than infarctions producing Q waves. It is concluded that the size of infarction determines the occurrence of several symptoms and complications diagnosed at admission or during stay in the coronary care unit.

Rapid enzyme release from acutely infarcted myocardium after early thrombolytic therapy: washout or reperfusion damage?

In a randomized study on early intracoronary thrombolytic therapy in patients with acute myocardial infarction (AMI), serial plasma enzyme activities were measured to analyze the rate of enzyme appearance in plasma with reference to treatment allocation, area at risk, and infarct size. Cumulative activities of alpha-hydroxybutyrate dehydrogenase (HBDH) appearing in plasma in the first 24 hours (Q24), 48 hours (Q48), and 72 hours (Q72) were calculated to obtain infarct size (= Q72) and rate of HBDH appearance in plasma (= Q24/Q72). Analyzed on the basis of "intention to treat" in 448 patients with AMI, the mean Q24/Q72 value (+/- SEM) was 0.653 +/- 0.011 in 230 patients receiving thrombolytic therapy; this value was significantly (p less than 0.001) higher than that observed in 218 patients receiving conventional therapy (0.504 +/- 0.012). In the thrombolysis group Q24/Q72 was independent of infarct size, whereas in the control group Q24/Q72 was negatively correlated with infarct size (r = -0.26; p less than 0.001). Plotted against the sum of ST segment elevations at admission (sigma ST) mean Q24 values were similar in both treatment groups, but mean Q48 and especially Q72 values were larger in the control group than in the thrombolysis group. We conclude that: (1) in reperfused infarctions the time course for development of infarct is accelerated in comparison to unreperfused infarcts; (2) this accelerated process of necrosis lasts about 40 to 50 hours, a duration that is hardly influenced by infarct size; and (3) the reperfusion-induced acceleration of enzyme release resembles the reoxygenation-induced enzyme release from anoxic hearts.(ABSTRACT TRUNCATED AT 250 WORDS)

Enzyme tests in the evaluation of thrombolysis in acute myocardial infarction

The activity of alpha-hydroxybutyrate dehydrogenase, creatine kinase, creatine kinase MB and aspartate aminotransferase was measured on serial plasma samples from patients with acute myocardial infarction. The study was part of a multicentre randomised trial of the effect of thrombolytic treatment in the acute phase of acute myocardial infarction. The applicability and comparability of enzyme tests for the estimation of myocardial injury were studied in 76 control patients and 74 patients treated with streptokinase. Treatment with streptokinase caused a considerable acceleration of enzyme release after acute myocardial infarction, both in patients with persistent coronary occlusion and in those with successful reperfusion. But this changed pattern of enzyme release did not affect the rate of enzyme elimination from plasma or the released proportions of different enzymes. Thus the assessment of infarct size by measurement of these enzyme activities can also be applied to patients treated with streptokinase. Moreover, the enzymes measured in the present study are all equally valid markers of myocardial injury.

Relation between infarct size and left ventricular performance assessed in patients with first acute myocardial infarction randomized to intracoronary thrombolytic therapy or to conventional treatment

Reperfusion of ischemic myocardium has been reported to increase the cumulative creatine kinase activity in plasma per gram of infarcted myocardium as assessed with the method of Shell et al. In an attempt to find out whether infarct size assessment using the method of Witteveen et al was affected by reperfusion, the relation between enzymatic infarct size was analyzed using Witteveen's method and left ventricular (LV) function parameters in 266 patients with first acute myocardial infarction randomized to intracoronary thrombolysis (n = 134) or conventional therapy (n = 132). Compared with patients allocated to conventional therapy, patients allocated to intracoronary thrombolysis had smaller enzymatic infarct size by 29% (p less than 0.001), smaller LV end-diastolic and end-systolic volume indexes by 10% (p less than 0.05) and 20% (p less than 0.005), respectively, and higher LV ejection fraction (55 +/- 1% vs 49 +/- 1%; p less than 0.001). The beneficial effects of thrombolytic therapy on LV performance were closely associated with thrombolysis-induced limitation of infarct size. The dependence from infarct size of LV end-diastolic volume, LV end-systolic volume, and ejection fraction was not different in the 2 therapy groups. It was concluded that Witteveen's method of infarct size assessment is not influenced by the presence of reperfusion. Therefore, this method was recommended for trials on recanalization in patients with acute myocardial infarction.

Exercise testing three days after onset of acute myocardial infarction

To determine the feasibility and predictive value of early exercise testing 72 hours after acute myocardial infarction, 109 consecutive patients who received reperfusion therapy were prospectively evaluated. In the group studied, in 87 (80%) the course was uncomplicated 3 days after admission, as defined by a lack of congestive heart failure, arrhythmias and angina, and 53 patients (49%) performed heart rate-limited (140 beats/min) treadmill exercise. These patients exercised for 7.9 +/- 3.4 minutes, achieving a heart rate of 129 +/- 11 beats/min and a systolic blood pressure of 151 +/- 27 mm Hg. The exercise test was not accompanied by any protracted ischemia, infarction or significant arrhythmias. Accompanying tomographic thallium-201 scintigraphy demonstrated a reversible perfusion defect in 14 patients (26%), no evidence for ischemia in 36 patients (69%) and an equivocal result in 3 patients (6%). Of the 14 patients with a positive exercise-thallium test result, 4 had an adverse clinical outcome of either reinfarction, postinfarction angina or ventricular tachycardia during hospital days 4 to 10; an adverse in-hospital outcome was not seen in the 40 patients with a negative exercise-thallium test result (p = 0.009). Thus, early exercise testing after acute myocardial infarction is safe in selected patients with an uncomplicated course and the test is predictive of in-hospital clinical outcomes.

Value of immediate coronary angioplasty following intracoronary thrombolysis in acute myocardial infarction

A total of 533 patients with acute myocardial infarction of less than 4-h duration were enrolled in the multicenter randomized trial of intracoronary thrombolysis compared to conventional treatment. In two of the five participating centers, an additional coronary angioplasty immediately after thrombolysis was attempted in 46 patients. According to the treatment allocation and early and late patency of the infarct related vessel, patients were subdivided into three groups: conventionally treated (group A); successful coronary angioplasty following thrombolysis with persistent patent infarct related vessel (group B); and late patency of the infarct related vessel postthrombolytic therapy without angioplasty (group C). The highest global ejection fractions were observed in group B (54% +/- 10%) and group C (55% +/- 13%), while the lowest ejection fraction was found in group A (47% +/- 14%). The sequential changes in global ejection fraction from the acute to the chronic stage was + 4% (p = 0.05) in group B, while no significant changes could be demonstrated in group C. Furthermore, in the group successfully treated by angioplasty, the improvement in global ejection fraction was more pronounced and persisted up to three months after the intervention. This was supported by analysis of regional myocardial function of the infarct zone (+ 16% improvement, p = 0.01). The long-term clinical follow-up (median 24 months) of the patients successfully treated by combined procedure of thrombolysis and angioplasty (group B) was most favourable with a lower incidence of re-infarction (6%), and late coronary bypass surgery (13%) and/or (re)-percutaneous transluminal coronary angioplasty (3%) was performed less frequently. These results suggest that reperfusion may need to be supplemented by additional revascularization procedures in order to optimize the changes of obtaining full functional recovery and so to improve the prognosis.

Which patients benefit most from early thrombolytic therapy with intracoronary streptokinase?

The effect of thrombolysis in acute myocardial infarction on enzymatic infarct size, left ventricular function, and early mortality was studied in subsets of patients in a randomized trial. Early thrombolytic therapy with intracoronary streptokinase (152 patients) or with intracoronary streptokinase preceded by intravenous streptokinase (117 patients) was compared with conventional treatment (264 patients). All 533 patients were admitted to the coronary care unit within 4 hr after onset of symptoms indicative of acute myocardial infarction. Four hundred eighty-eight patients were eligible for this detailed analysis, and 245 of these were allocated to thrombolytic therapy and 243 to conventional treatment. Early angiographic examinations were performed in 212 patients allocated to thrombolytic therapy. Patency of the infarct-related artery was achieved in 181 patients (85%). Enzymatic infarct size, as measured from cumulative alpha-hydroxybutyrate dehydrogenase release, was smaller in patients allocated to thrombolytic therapy (median 760 vs 1170 U/liter in control patients, p = .0001). Left ventricular ejection fraction measured by radionuclide angiography before discharge from the hospital was higher after thrombolytic therapy (median 50% vs 43% in control patients, p = .0001). Three month mortality was lower in patients allocated to thrombolytic therapy (6% vs 14% in the control group, p = .006). With the use of multivariate regression analysis, infarct size limitation, improvement in left ventricular ejection fraction, and three month mortality were predicted by sum of the ST segment elevation, time from onset of symptoms to admission, and Killip class at admission. Thrombolysis was most effective in patients admitted within 2 hr after onset of symptoms and in patients with a sum of ST segment elevation of 1.2 mV or more. On the other hand, no beneficial effects of streptokinase on enzymatic infarct size, left ventricular function, or mortality were observed in the subset of patients with a sum of ST segment elevation of less than 1.2 mV who were admitted between 2 and 4 hr after onset of symptoms.