Incidence of left-ventricular thrombosis after acute transmural myocardial infarction. Serial evaluation by two-dimensional echocardiography

Ischemic stroke and intracranial hemorrhage following thrombolytic therapy for acute myocardial infarction: a risk-benefit analysis

Stroke is a potentially serious complication of acute myocardial infarction (AMI). In the prethrombolytic era, most strokes were attributed to cerebral embolism. On the basis of available information, the occurrence of stroke in the thrombolytic era appears to be less than in the prethrombolytic era. In the thrombolytic era, the occurrence of various forms of intracranial hemorrhage has increasingly been documented in addition to cerebral embolism, with intriguing features. In general, however, the delineation of specific stroke subtypes has been imprecise and must take into account factors that are unique to this setting. Age is a risk factor for both ischemic and hemorrhagic stroke. Potential risk factors for intracranial hemorrhage include hypertension, dosage of fibrinolytic agents, and prior neurologic disease. Potential causes of intracranial hemorrhage include combined fibrinolytic/adjunctive therapies, various cerebrovascular lesions, and head trauma. Existing data suggest that mortality related to stroke complicating AMI is on the decline as well. More research is needed in order to quantify precisely the occurrence and proportions of stroke subtypes, risk factors, and causes in order to define mechanisms and preventive measures.

Noninvasive and invasive testing after myocardial infarction

Recurrent myocardial ischemia, moderate to marked depression of left ventricular systolic function, and late-occurring or recurrent cardiac arrhythmia indicate increased risk for patients with acute myocardial infarction. Some patients, on the basis of high risk and/or unsuccessful response, will be early candidates for early aggressive diagnostic and therapeutic procedures. Others will have clinical indicators of increased risk during hospitalization that warrant diagnostic coronary arteriographic assessment before discharge. Still other patients with low risk clinical characteristics can be further stratified by predischarge or early postdischarge stress testing for myocardial ischemia, left ventricular functional reserve, and/or likely occurrence of arrhythmias. Some stratified to low risk patients will be treated only with secondary prevention measures. Others at higher risk will undergo more aggressive evaluation and subsequent medical or surgical therapy.

Effects of intravenous recombinant tissue-type plasminogen activator therapy on the incidence and associations of left ventricular thrombus in patients with a first acute Q wave anterior myocardial infarction

Consecutive survivors of a first Q wave anterior myocardial infarction were studied to observe the impact of recombinant tissue-type plasminogen activator (rt-PA) therapy on the incidence and associations of left ventricular thrombus. Fifty-four patients received rt-PA within 4 hours after the onset of cardiac pain, followed by heparin infusion. Forty-four patients who did not qualify for rt-PA therapy but who were anticoagulated with heparin served as a control group. Two-dimensional echocardiography was performed in all patients on days 3 and 7 to detect thrombi and analyze wall motion. Ejection fraction was determined by radionuclide angiography in all patients on day 7. Apical thrombi were detected on day 3 in three patients (5.5%) who received rt-PA and in eight control patients (18%) (p less than 0.05). All patients with a thrombus had apical dyskinesis and 8 of 11 (73%) had an aneurysm. Of the 87 patients without thrombosis, apical dyskinesis and aneurysm were present in 42 (48%) and 11 (13%) patients, respectively (p less than 0.01). Ejection fractions and wall motion scores of patients without a thrombus were significantly better when compared with data from those with a thrombus. There were fewer patients with apical dyskinesis (17 of 54) in the group receiving rt-PA therapy compared with the control group (36 of 44) (p less than 0.01). Ejection fractions and wall motion scores were better in patients who received rt-PA compared with control subjects (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Role of Doppler echocardiography in coronary artery disease

Doppler echocardiography can have a major role in the evaluation of patients with coronary artery disease. This review deals with the imaging planes in relation to coronary vascular territories and the role of Doppler echocardiography in evaluating patients with acute and chronic ischemic syndromes.

Left ventricular thrombus in anterior acute myocardial infarction after thrombolysis. A GISSI-2 connected study

BACKGROUND

Streptokinase reduces the incidence of left ventricular thrombosis after acute myocardial infarction. However, it is unknown whether a similar effect can be obtained with different thrombolytic agents and whether subcutaneous calcium heparin can have an additional efficacy.

METHODS AND RESULTS

To compare the effects of two different thrombolytic agents combined or not with heparin on the incidence and features of left ventricular thrombi and their related embolic events, we performed a GISSI-2 ancillary echocardiographic study (the first echocardiogram obtained within 48 hours of symptoms onset and the second before hospital discharge) that enrolled 180 consecutive patients (mean age, 63 +/- 11 years, 142 men) with a first anterior acute myocardial infarction. Patients were randomized into four groups of treatment: recombinant tissue-type plasminogen activator (rt-PA) (n = 47), rt-PA plus heparin (n = 45), streptokinase (n = 39), and streptokinase plus heparin (n = 49). Left ventricular thrombosis was observed in 51 of 180 patients (28%). No significant differences were found concerning the incidence of thrombi in the four treatment groups. Mural shape of left ventricular thrombi was found more frequently than the protruding shape (71% versus 29% at the first examination, 64% versus 36% at the second), particularly in heparin-treated patients (93% versus 7% at first examination, 70% versus 30% at the second). Only one embolic event (0.5%) occurred during the hospitalization.

CONCLUSIONS

We conclude that 1) the rate of left ventricular thrombi does not differ in patients with acute myocardial infarction treated either with streptokinase or rt-PA, 2) subcutaneous heparin, when begun 12 hours after intravenous thrombolysis, does not appear to further reduce the occurrence of thrombi but seems to influence the shape of left ventricular thrombi, and 3) during the predischarge period, embolic events are rare in patients treated by thrombolysis.

Incidence of left ventricular thrombi formation after thrombolytic therapy with recombinant tissue plasminogen activator, heparin, and aspirin in patients with acute myocardial infarction

To evaluate the prevalence of left ventricular thrombi after thrombolytic therapy, 144 consecutive patients with acute myocardial infarction (AMI) were prospectively studied with two-dimensional echocardiography 1 and 8 days after admission. Patients were treated 2.1 +/- 0.8 hours after the onset of symptoms. Thrombolytic protocol included 120 mg of recombinant tissue plasminogen activator (rt-PA), 5000 IU of heparin, followed by a continuous infusion of 25,000 IU/24 hours for at least 5 days, and 250 mg of aspirin a day. Seventy-six patients had AMI of the anterior wall; of these, seven (9.2%) developed left ventricular thrombi. The remaining 68 patients had infarctions of the inferior wall; of these, two (2.9%) developed left ventricular thrombi. Since anterior wall infarction not treated with thrombolytic therapy is associated with a 25% to 40% rate of left ventricular thrombi, we conclude that early thrombolytic therapy with rt-PA, heparin, and aspirin reduces the formation of left ventricular thrombus in AMI of the anterior wall. Apical left ventricular thrombi developed more frequently in patients with previous infarctions compared with those without (4 of 17 versus 4 of 127, p = 0.01). During the 12-month follow-up period, no patient in the study had manifestations of peripheral emboli.

Cerebrovascular accident complicating acute myocardial infarction: incidence, clinical significance and short- and long-term mortality rates. The SPRINT Study Group

PURPOSE

The purpose of this study was to report the incidence, the antecedents, and the clinical significance of clinically recognized cerebrovascular accidents or transient ischemic attacks (CVA-TIA) complicating acute myocardial infarction.

PATIENTS AND METHODS

During 1981 to 1983, a secondary prevention study with nifedipine (SPRINT) was conducted in 14 hospitals in Israel among 2,276 survivors of acute myocardial infarction. During the study, demographic, historical, and medical data were collected on special forms for all patients with diagnosed acute myocardial infarction in 13 of these 14 hospitals (the SPRINT registry, n = 5,839). Mortality follow-up was completed for 99% of hospital survivors for a mean follow-up of 5.5 years (range: 4.5 to 7 years).

RESULTS

The incidence of CVA-TIA was 0.9% (54 of 5,839). The latter rate increased significantly only with age, from 0.4% among patients up to 59 years old to 1.6% among those aged greater than or equal to 70 years. Multivariate analysis identified age, congestive heart failure, and history of stroke as predictors of CVA-TIA during the acute phase of myocardial infarction. Patients with CVA-TIA exhibited a complicated hospital course, with a 15-day mortality rate of 41%. Subsequent mortality rates in survivors at 1 and 5 years were 34% and 59%, respectively. Rates at the same time points in patients without CVA-TIA were 16%, 11%, and 29% (p less than 0.01). In a multivariate analysis that included age, gender, congestive heart failure, history of previous myocardial infarction, and hypertension, CVA-TIA was independently associated with increased 15-day mortality (covariate-adjusted odds ratio [OR] = 2.62; 90% confidence interval [CI], 1.59 to 4.32), as well as subsequent 1-year (OR = 3.29; 90% CI, 1.70 to 6.36) and long-term (mean follow-up = 5.5 years) mortality (OR = 2.46; 90% CI, 1.30 to 4.69).

CONCLUSION

In this large cohort of consecutive patients with myocardial infarction, CVA-TIA was a relatively infrequent complication of acute myocardial infarction. Factors independently favoring the occurrence of CVA-TIA were old age, previous CVA, and congestive heart failure. CVA-TIA occurring during acute myocardial infarction independently increased the risk of early death threefold as well as the risk of long-term mortality in early-phase survivors. (2.5-fold).

Cerebrovascular events after myocardial infarction: analysis of the GISSI trial. Gruppo Italiano per lo Studio della Streptochinasi nell'Infarto Miocardico (GISSI)

OBJECTIVES

To describe the epidemiology of cerebrovascular events in patients given or not given fibrinolytic treatment and to assess the prognostic implications and risk factors.

DESIGN

Case series derived from the GISSI randomised trial.

SETTING

176 coronary care units in Italy giving various levels of care.

PATIENTS

5860 patients with acute myocardial infarction treated with 1.5 million units of intravenous streptokinase and 5852 patients not given fibrinolytic treatment.

MAIN OUTCOME MEASURES

Cerebrovascular event, sex, age, blood pressure, history of previous infarct, site of infarction, and Killip class.

RESULTS

99 of 11,712 patients (0.84%) had a cerebrovascular event. Older age, worse Killip class, and anterior location of infarction seemed to be risk factors for cerebrovascular events (40/3201 aged 65-75 v 42/7295 aged less than 65, odds ratio 2.18; 9/437 class 3 v 55/8277 class 1, 1.81; and 57/4878 anterior v 24/4013 posterior, 1.96). No significant difference was found in the rate of cerebrovascular events between patients treated with streptokinase and controls (45/5852 (0.92%) streptokinase v 54/5860 (0.77) control). More patients in the streptokinase group than in the control group had cerebrovascular events (especially haemorrhagic strokes) on day 0-1 after randomisation (27 streptokinase v 7, control), although this was balanced by late events in control patients (54 streptokinase v 45 control at one year). The mortality of patients who had a cerebrovascular event was higher than that of those who did not (47% (47/99) v 11.6% (1350/11,613].

CONCLUSIONS

Although the incidence of cerebrovascular events complicating myocardial infarction was low, they increased morbidity and mortality. Treatment with streptokinase did not significantly alter the incidence, but age and poor haemodynamic state were associated with an increased risk.

Acute anterior myocardial infarction: streptokinase prevents ventricular thrombosis independently of its effect on infarct size

Left ventricular thrombosis (LVT) is a frequent complication after acute anterior myocardial infarction (AMI). The purpose of this study is to evaluate whether streptokinase (SK) therapy prevents LVT, and whether this effect is due to the preservation of left ventricular function or to the fibrinolytic action of the drug. Sixty-five patients who underwent a left ventricular angiography within 2 months after a first AMI were studied. Twenty-eight patients (SK group) received SK 1,500,000 U i.v. administered over 60 min within 6 h from the onset of symptoms. A lower incidence of LVT was found in the SK group (p = 0.0003). We divided patients into two classes according to the value of akinetic-dyskinetic area (AD): the first group with a lower value of AD, the second group with a higher value of AD. In both groups, a reduced incidence of LVT was associated with SK therapy (p = 0.014, p = 0.015, respectively). Early infusion of SK during AMI seems to prevent the development of LVT, with an effect partly independent from its action on infarct size for small to large myocardial infarction.

Regression of intracardiac thrombus after embolic stroke

Using two-dimensional echocardiography, we studied the pathophysiology of intracardiac thrombus regression accompanied by anticoagulant therapy in 82 consecutive patients with acute cardiogenic cerebral embolism. We noted intracardiac thrombus in 15 patients; nine of the 15 were started on anticoagulant therapy with warfarin potassium to maintain the prothrombin time between 2.5 and 3.5 (international normalized ratio). Serial two-dimensional echocardiograms were obtained for these nine patients before and after anticoagulation, with the plasma levels of fibrinopeptide A, fibrinopeptide B beta 15-42, and D-dimer measured at the same time. In eight of the nine patients the intracardiac thrombi gradually decreased in size while the plasma level of fibrinopeptide A fell to within the normal range and the plasma levels of fibrinopeptide B beta 15-42 and D-dimer remained above the normal ranges. In the other patient the thrombus disappeared, with embolization to the right arm immediately after starting anticoagulant therapy. Mobile or small thrombi regressed earlier than nonmobile or large ones. We conclude that regression of intracardiac thrombi after anticoagulation may be based on the relative predominance of plasma fibrinolytic activity over anticoagulation-inhibited thrombin activity.

Management of the patient following coronary thrombolysis

Myocardial salvage can be maximized by the early institution of thrombolytic therapy and aspirin. Certain patients may benefit from the administration of intravenous heparin, beta blockers, or nitroglycerin. The routine use of percutaneous transluminal coronary angioplasty (PTCA) or calcium-channel blockers does not appear to be warranted. Recurrent myocardial ischemia should be vigorously treated with medical therapy and there may be value in cardiac catheterization, followed by PTCA or bypass surgery, depending upon the extent of myocardium at risk and the underlying coronary anatomy. Long-term morbidity and mortality may be reduced by instituting aspirin and beta blockers as well as by modifying risk factors. There is no evidence for the long-term benefit from any calcium-channel blocker. Oral anticoagulation may be warranted in those patients with a mural thrombus, congestive heart failure, or atrial fibrillation. ACE inhibitors may be of value in the presence of left ventricular dysfunction and certainly in the presence of symptomatic congestive heart failure. Antiarrhythmic therapy is generally indicated only for symptomatic or life-threatening arrhythmias. Residual myocardial ischemia should be sought by exercise testing, and those patients with poor exercise tolerance generally warrant cardiac catheterization in consideration for revascularization.

Preventive strategies in management of acute myocardial infarction

Recent studies on pathogenetic mechanisms, supplemented by findings in clinical trials point the way to a logical approach to acute evolving myocardial infarction. This is designed in the earliest stage to limit infarction through reduction in myocardial oxygen demands, improvement in collateral blood supply and dissolution of coronary thrombus, to prevent in a later stage coronary reocclusion through administration of antiplatelet agents, and then to prevent infarct expansion through reduction in ventricular wall tension throughout the period of repair. Application of such an approach holds the promise of reducing infarct size and all the complications of infarction, as well as short and long-term mortality. The approach is active and aggressive, and contrasts with the approach applied a decade ago, where infarction was accepted as inevitable and therapies were reserved for managing its complications.

Left ventricular thrombectomy in the early postinfarction period

Emergency left ventricular thrombectomy was performed on four patients soon after infarction. In three patients surgery was carried out after embolisation had occurred and when a large, residual, protruding, mobile thrombus remained in the left ventricle. Surgery was performed in the fourth patient after a high risk thrombus was detected and initial attempts to lyse it had failed. All four patients had an uneventful recovery and were discharged within two weeks of surgery. These cases indicate that the therapeutic option of left ventricular thrombectomy is feasible for patients with acute infarcts and problematic left ventricular thrombi.

Echocardiography in coronary artery disease

Echocardiography has a major role in the evaluation of patients with CAD. To obtain the maximal amount of information using this technique, certain basic principles relating to regional myocardial mechanics during ischemia and flow-function relations are required. In addition, a detailed knowledge of cardiac anatomy and the three-dimensional orientation of the heart within the chest cavity is required to access meaningful information from two-dimensional planes. Furthermore, skill is also required in acquiring data in proper imaging planes and in separating true (actual pathology) from the false (artifacts, etc.). Echocardiography is not a "mature" technology. It is still developing and it is sometimes difficult to keep up with the advances. However, keeping abreast of these developments is essential to fully exploit the advantages of this technique. In addition, knowledge of the ever-changing aspects of CAD is required in order to correctly interpret visual information in context of a particular patient. Finally, more clinical studies are needed to further define the role of echocardiographic techniques in patients with CAD.

111In platelet imaging of left ventricular thrombi. Predictive value for systemic emboli

To determine whether a positive indium 111 platelet image for a left ventricular thrombus, which indicates ongoing thrombogenic activity, predicts an increased risk of systemic embolization, we compared the embolic rate in 34 patients with positive 111In platelet images with that in 69 patients with negative images during a mean follow-up of 38 +/- 31 (+/- SD) months after platelet imaging. The positive and negative image groups were similar with respect to age (59 +/- 11 vs. 62 +/- 10 years), prevalence of previous infarction (94% vs. 78%, p less than 0.05), time from last infarction (28 +/- 51 vs. 33 +/- 47 months), ejection fraction (29 +/- 14 vs. 33 +/- 14), long-term or paroxysmal atrial fibrillation (15% vs. 26%), warfarin therapy during follow-up (26% vs. 20%), platelet-inhibitory therapy during follow-up (50% vs. 33%), injected 111In dose (330 +/- 92 vs. 344 +/- 118 microCi), and latest imaging time (greater than or equal to 48 hours in all patients). During follow-up, embolic events occurred in 21% (seven of 34) of patients with positive platelet images for left ventricular thrombi as compared with 3% (two of 69) of patients with negative images (p = 0.002). By actuarial methods, at 42 months after platelet imaging, only 86% of patients with positive images were embolus free as compared with 98% of patients with negative images (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Natural history of left ventricular thrombi: their appearance and resolution in the posthospitalization period of acute myocardial infarction

A series of 198 consecutive patients with acute myocardial infarction were prospectively studied before hospital discharge and during 24.0 +/- 8.6 months of follow-up. A predischarge thrombus was found in 38 (31%) of 124 patients with anterior infarction but in none of 74 patients with inferior infarction (p less than 0.001). Early thrombolytic therapy in 34 patients did not decrease the rate of thrombus occurrence. Acute anterior infarction, ejection fraction less than or equal to 35% and apical dyskinesia or aneurysm (but not akinesia) were significantly related to the appearance of thrombus during hospitalization by stepwise logistic regression analysis. Echocardiographic follow-up of 159 patients for at least 6 months (mean 26.6 +/- 8.4) revealed that thrombus disappeared in 14 (48%) of 29. Disappearance of thrombus was related to predischarge apical akinesia (but not dyskinesia) and to warfarin therapy during the follow-up period. A new thrombus first appeared after hospital discharge in 13 of 130 patients, and in 7 of the 13 it resolved during further follow-up. Thus, 30% (13 of 42) of thrombi in these patients appeared after discharge from the hospital. Three factors were related to occurrence of new thrombi during the follow-up period: deterioration in left ventricular ejection fraction, predischarge ejection fraction less than or equal to 35% and ventricular aneurysm or dyskinesia. Systemic embolism occurred in six patients, all with a predischarge thrombus (p less than 0.001). Mobility of the thrombus was the only variable significantly related to subsequent embolic events (p = 0.001) by logistic regression analysis. Thus, the predischarge echocardiogram identifies patients with thrombus and those at highest risk of embolic events. It can indicate patients who are likely to have thrombus resolution and those at risk of developing a new thrombus after hospital discharge. Follow-up echocardiograms may help in guiding the length of long-term anticoagulant therapy. Four additional patients with a predischarge apical mobile thrombus (not part of the consecutive series) received thrombolytic therapy. In two of the four, lysis of thrombus was achieved without complications, but systemic embolism occurred in the other two, and proved fatal in one.

Systemic embolization following thrombolytic therapy for acute myocardial infarction

We describe a patient with acute inferior myocardial infarction who developed a "saddle" aortic embolus during streptokinase infusion. Three months previously, this patient had sustained an anterior infarction, and an apical aneurysm was found. This patient's embolus had most probably originated from a left ventricular mural thrombus that had been dislodged by streptokinase. As fibrinolytic treatment is gaining wide acceptance, physicians should be aware of this rare, but possible, complication.

Prediction of apical thrombus formation in acute myocardial infarction based on left ventricular spatial flow pattern

The predictive value of the left ventricular spatial flow pattern for thrombus formation was determined in 62 patients with acute myocardial infarction. A normal flow pattern by pulsed Doppler echocardiography was characterized by 1) simultaneous onset of blood motion at the mitral valve and apical level, and 2) a discontinuous Doppler signal along the lateral wall and interventricular septum. The flow pattern was assessed by these criteria, within 24 h after the onset of complaints and after 6 and 12 weeks. In 46 of the 62 patients, a normal flow pattern was found at the first examination; none of these 46 patients developed a thrombus during the study period. An abnormal flow pattern was seen at the first examination in 16 patients; this pattern normalized during follow-up in 6 patients, none of whom developed a thrombus. In the other 10 patients the abnormal flow pattern persisted, and 7 of these developed a thrombus. These findings suggest that a normal left ventricular flow pattern in the setting of acute myocardial infarction is not associated with subsequent thrombus formation. This observation may be of importance if anticoagulation is considered.

Left ventricular aneurysmectomy after myocardial infarction following detection of left ventricular thrombosis by magnetic resonance imaging

A 54-year-old man with a history of myocardial infarction presented with recurrent transient ischemic attacks 7 yr after the acute event. The emboli originated from a left ventricular thrombus despite adequate oral anticoagulant therapy. The thrombus was best detected with magnetic resonance imaging and had to be removed by surgery.

The effects of long-term antithrombotic treatment on left ventricular thrombi in patients after an acute myocardial infarction

Sixty patients (48 men and 12 women; aged 36 to 72 years, mean 48 +/- 9), who survived an acute anterior myocardial infarction and in whom left ventricular thrombus was detected by cross-sectional echocardiography 1 to 2 days before they were discharged from the hospital, were prospectively studied. All had evidence of left apical wall motion abnormalities. They were randomly divided into three groups of 20 patients each. Group A was given a full dose of oral anticoagulants, group B was given aspirin, 650 mg/day, and group C received no antithrombotic therapy. Echocardiography was performed every 3 months in all patients, and they were followed for 9 to 24 months (mean 16 +/- 5 months). Twelve patients in group A had complete resolution of the thrombus and three had a significant decrease in the size of the thrombus (greater than or equal to 50% of initial thickness) during the first trimester after acute infarction. In group B the thrombus resolved in nine patients and was significantly diminished in four during the first trimester of follow-up. In group C the thrombus resolved in two patients during the first trimester and showed a significant decrease in size in two patients during the second trimester of follow-up. Two patients in group C initially had recurrent transient cerebral ischemic attacks, which did not recur after aneurysmectomy. One patient in group C had a peripheral embolic episode in the femoral artery.(ABSTRACT TRUNCATED AT 250 WORDS)

Decision analysis concerning the application of echocardiography to the diagnosis and treatment of mural thrombi after anterior wall acute myocardial infarction

The diagnostic and therapeutic approach to the problem of mural thrombi after acute myocardial infarction is uncertain. It is clear that the main therapeutic goal is the prevention of embolic strokes. Although it is known that the incidence of thrombi is greatest after anterior wall infarctions, there is uncertainty concerning (1) the probability of a mural thrombus; (2) the sensitivity and specificity of echocardiography in making the diagnosis; (3) the probability that a thrombus will embolize and result in a cerebrovascular accident (CVA); (4) the efficacy of warfarin in preventing embolization; and (5) the probability of bleeding with and without warfarin. To study this problem in patients who have had an anterior wall myocardial infarction, a model was created in which reasonable estimates for the unknown parameters were determined from published medical studies. The model was designed to consider patients if they were or were not treated during the initial hospitalization with heparin. The probability of thrombus was estimated at 0.30, sensitivity and specificity of echocardiography at 0.85 and 0.85, probability that a thrombus will embolize at 0.15, efficacy of anticoagulation of 0.75, probability of bleeding with warfarin at 0.03 and probability of bleeding without warfarin at 0.005. Probabilities of a CVA and of bleeding with and without warfarin were determined if all patients were anticoagulated, if patients with positive echocardiographic results were treated, if patients with negative echocardiographic results were treated and if echocardiographically guided therapy was instituted in which patients with positive echocardiographic results are treated and patients with negative results are not treated.(ABSTRACT TRUNCATED AT 250 WORDS)

The natural history of left ventricular thrombus in myocardial infarction: a rationale in support of masterly inactivity

One hundred five unselected and consecutive patients were prospectively studies after acute transmural myocardial infarction to assess the incidence of mural thrombus formation and to relate the presence of thrombus to patient outcome in terms of systemic embolic events, functional class and survival. In 87 patients, optimal quality two-dimensional echocardiographic studies were obtained and were repeated at daily intervals to detect mural thrombus formation. The site of infarction was anterior in 53 patients and inferior in 34. On admission, all patients received subcutaneous heparin and antiplatelet agents (aspirin, dipyridamole); none received full anticoagulant therapy. Left ventricular mural thrombus was visualized between 2 and 11 days (median 6) after the clinical onset of infarction in 21 (40%) of the 53 patients with anterior infarction. No patients with inferior infarction had echocardiographic evidence of thrombus formation. During follow-up of 22 to 51 months (mean 39), none of the 21 patients with mural thrombus had clinical evidence of systemic embolism. One patient with inferior and one with anterior infarction had a cerebral embolus 7 days and 9 months, respectively, after the acute event, but neither of these patients had echocardiographic evidence of left ventricular thrombus at any stage. Echocardiography performed at 1 and 2 years of follow-up showed persistent evidence of thrombus in only 8 (31%) and 5 (24%) of the 21 patients, respectively. On admission, the functional class of patients with anterior myocardial infarction and thrombus was similar to that of patients without ventricular thrombus.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of thrombolytic treatment followed by full dose anticoagulation on the frequency of left ventricular thrombi in acute myocardial infarction

This study evaluated the influence of thrombolysis followed by full anticoagulation on the frequency of left ventricular (LV) thrombi after acute myocardial infarction (AMI). Nineteen consecutive patients with a first anterior wall AMI who received 1,500,000 IU of streptokinase within 3 hours of symptom onset, followed by full anticoagulation, underwent echocardiographic studies within 24 hours of symptoms, and then on days 2, 3, 5, 7, 12, 30 and 90. Forty-four patients, with comparable clinical features and echocardiographic protocol but without antithrombotic therapy, served as the control group. LV thrombi developed in 4 of 19 (21%) treated patients and in 23 of 44 (52%) control subjects (p = 0.02). LV aneurysm or major wall motion abnormalities were noted in 8 of 19 (42%) treated patients and in 30 of 44 (68%) control subjects (p less than 0.05). No significant difference was found between treated and untreated patients when comparing the incidence of thrombi in the subgroups of patients with aneurysm or major wall motion abnormalities (3 of 8 vs 21 of 30) and in the subgroups with less extensive LV dysfunction. Thrombi disappeared during hospitalization in 3 of 4 treated patients, but in none of the controls. Fewer patients treated with intravenous streptokinase followed by full anticoagulation developed LV thrombi compared to patients treated with conventional therapy. This difference may be related to a reduced occurrence of major LV wall motion abnormalities. Resolution of thrombi frequently occurs in the hospital phase of AMI; therefore, only frequent echocardiographic examinations can assess the true frequency of LV thrombi.

Antithrombotic therapy in acute myocardial infarction: prevention of venous, left ventricular and coronary artery thromboembolism

The antithrombotic approach to patients with acute myocardial infarction in the prevention of venous, left ventricular and coronary artery thromboembolic events should be based on an understanding of pathogenesis and risk. Coronary thrombotic events involve conditions of high shear rate present in areas of vessel stenosis or disrupted atherosclerotic plaque, which lead to activation of both platelets and the coagulation system, and are best prevented by platelet inhibitors alone or in combination with an anticoagulant. However, thromboembolism that originates in the venous system or cardiac chambers is related to situations of blood stasis and low shear rate, which predominantly result in clotting activation and fibrin-thrombus formation and are best approached with anticoagulant therapy. For prevention of venous thrombosis and pulmonary embolism, early mobilization is essential and should be supplemented by low-dose heparin in patients at high risk, including the elderly and those with large infarcts, heart failure or previous thromboembolic events. For prevention of left ventricular mural thrombosis and systemic embolism, high-dose heparinization is indicated in patients with large infarcts, particularly in the anterior location and in those with heart failure. Subsequently, warfarin therapy should be considered for patients at high embolic risk, including those with echocardiographic evidence of mobile and protruding thrombi, severe left ventricular dysfunction or prior emboli. In patients with acute infarction, aspirin is recommended for preventing coronary reocclusion and reinfarction. Although anticoagulants may also be of benefit for this purpose, their use is still controversial.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevention of left ventricular mural thrombus

Acute myocardial infarction is associated with a high incidence of left ventricular mural thrombosis, which causes most of the systemic emboli. A double-blind trial was undertaken in patients with anterior transmural myocardial infarction to evaluate the ability of a high-dose heparin regimen to prevent left ventricular mural thrombosis. The high dose consisted of 12,500 U of calcium heparin subcutaneously every 12 hours for 10 days, which was compared with a low dose consisting of 5,000 U every 12 hours. The formation of left ventricular mural thrombosis was assessed by means of 2-dimensional echocardiography on day 10 after infarction. The high-dose group had a significantly lower incidence of left ventricular mural thrombosis than did the low-dose group. This was achieved without increasing the incidence of bleeding. The benefits of high-dose heparin were associated with maintaining plasma heparin concentrations at 0.2 U/ml and activated partial thromboplastin time between 50 and 60 seconds.

Lack of correlation between intracavitary thrombosis detected by cross sectional echocardiography and systemic emboli in patients with dilated cardiomyopathy

The correlation between intracavitary thrombosis detected by cross sectional echocardiography and systemic embolism was studied in 126 consecutive patients with idiopathic dilated cardiomyopathy who were examined from January 1980 to September 1987. A total of 1041 serial echocardiograms were obtained with 3.5 and 5 MHz transducers. The mean follow up period was 41.2 months. The survival rate was 88% at two years and 56% at five years. Echocardiography showed intracavitary thrombi in 14 (11.1%) patients; 13 were mural and 11 were localised at the apex of the left ventricle. Twelve patients (8.4%) had systemic emboli; this corresponded to an incidence of new embolic events of 1.4 for 100 patient-years. Patients with intracavitary thrombi or systemic emboli were treated with oral anticoagulants, as were nine in functional class IV of the New York Heart Association, for 61 patient-years. The cumulative observation period for the whole population study was 418 patient-years. None of the patients with intracavitary thrombosis had embolic complications and none of those with embolism had intracavitary thrombi. Rates of intracavitary thrombosis and systemic embolism in this series were low and there was no overlap between the two events. This may have been because the patients did not have severe dilated cardiomyopathy, because echocardiography did not detect all the thrombi, or because patients were treated with oral anticoagulants. The presence of intracardiac thrombosis detected by cross sectional echocardiography is not predictive of systemic embolism in patients with idiopathic dilated cardiomyopathy. Criteria for the use of the anticoagulant treatment remain largely empirical in these cases.

Prognostic significance of the extent of myocardial injury in acute myocardial infarction treated by streptokinase (the GISSI trial)

To evaluate the different contributions of infarct site and infarct extent in determining the in-hospital outcome and efficacy of thrombolytic therapy, 8,731 patients with a first Q-wave acute myocardial infarction (AMI) enrolled in the GISSI trial were studied. On the basis of the standard 12-lead electrocardiogram, the sample was classified in 2 ways: classic electrocardiographic site pattern (anterior, inferior, lateral and multiple location), and number of standard electrocardiographic leads with ischemic ST elevation (small, modest, large and extensive infarct in 2 to 9 leads). In-hospital mortality was evaluated according to infarct site, infarct extent and fibrinolytic treatment. The mortality rate was differently distributed in the various infarct sites. Streptokinase significantly reduced mortality only in anterior (13.8 vs 18.7%) and multiple site infarcts (8.1 vs 12.5%). According to the infarct extent observed, there is a progressive increase in the mortality rate--from 6.5% in small infarcts to 9.6% in modest, 14.3% in large and 21.7% in extensive. No significant benefit was obtained by streptokinase in small infarcts; in contrast, a significant decrease in mortality was achieved in modest (7.7 vs 11.4%), large (12.8 vs 16.6%) and extensive infarcts (19.5 vs 23.9%). Thus, the extent of myocardial injury seems to be more relevant than the site in determining in-hospital mortality and efficacy of thrombolytic therapy.

Myocardial inotropic responses to aggregating platelets and modulation by the endocardium

Ventricular mural thrombi complicate many cardiac diseases. The endocardial endothelium can modulate the mechanical performance of subjacent myocardium and mediate responses to certain physiopharmacologic agents. We studied the effects of aggregating platelets on the contractile performance of isolated cardiac muscle. The role of the endocardium was investigated by selectively damaging it by very brief (1 second) exposure to 1% Triton X-100 in some muscle preparations before experiments. Cat papillary muscles (n = 54) were attached to an electromagnetic length-tension transducer in organ baths containing Krebs-Ringer solution (1.25 mM Ca2+, 35 degrees C), and stimulated electrically at 0.2 Hz. Homologous washed platelets (final concentration 3 x 10(11)/l) aggregated spontaneously on addition to baths. Mechanical performance increased significantly more in muscles with damaged endocardium than in intact muscles (p less than 0.05); total peak isometric twitch tension increased by 31.8 +/- 7.8% (with damaged endocardium) and 11.8 +/- 2.6% (with intact endocardium), and peak isotonic twitch shortening increased by 36.7 +/- 7.8% (with damaged endocardium) and 9.6 +/- 2.0% (with intact endocardium). Increases in maximum velocity of unloaded shortening were similar in both muscle groups. Time to half isometric twitch tension decline decreased in intact muscles (3.6 +/- 1.0%) but increased in Triton-treated muscles (2.5 +/- 1.3%, p = 0.003 for difference between groups). The inotropic response to platelets in muscles with intact endocardium was unaltered by pretreatment of muscles with indomethacin (10 microM) or by stimulation of platelet aggregation with thrombin (0.1 unit/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Left ventricular thrombus incidence and behavior studied by serial two-dimensional echocardiography in acute anterior myocardial infarction: left ventricular wall motion, systemic embolism and oral anticoagulation

Serial two-dimensional echocardiography was performed to detect left ventricular thrombus in 92 consecutive patients with a confirmed first acute anterior myocardial infarction. Thirty left ventricular thrombi were diagnosed in these 92 patients. The cumulative percent of identified thrombus in each echocardiographic examination in the surviving patients was 27% at less than 24 h; 57% at 48 to 72 h; 75% at 1 week and 96% at 2 weeks. The thrombus shape was defined as mural in 53% and protruding in 47% of patients. Systemic embolism (stroke) was noted during hospitalization in two patients with a protruding thrombus. At 12 weeks of follow-up, patients with thrombus had poorer (and almost unchanged from baseline) global left ventricular function as expressed by wall motion score compared with that of patients without thrombus, who exhibited significant improvement. Global left ventricular wall motion in patients with persisting or resolved thrombus was similar during follow-up. Apical wall motion worsened in 70% of the patients with persisting thrombus and in 25% of the patients with resolved thrombus (p less than 0.1). In the 22 surviving patients with thrombus, resolution or change in thrombus shape or size was noted in 14 of the 15 patients receiving anticoagulant therapy and in 4 of the 7 untreated patients. Six of the 18 patients with an early- (48 to 72 h) and none of the 12 patients with a later-formed thrombus died. Maximal serum enzyme levels, percent with Killip functional class III to IV and left ventricular wall motion score were higher in the patients with an early- than in those with a later-formed thrombus.(ABSTRACT TRUNCATED AT 250 WORDS)

Relation of plasma D-dimer concentrations to coronary artery reperfusion before and after thrombolytic treatment in patients with acute myocardial infarction

This study was designed to investigate the possible role of pre- and posttreatment plasma D-dimer concentration as a reflection of coronary artery thrombolysis. Blood was collected from 206 patients with angiographically documented acute coronary occlusion presenting within 6 hours of symptom onset who were enrolled in a prospective study comparing intravenous APSAC (30 U) (IV-APSAC) with intracoronary streptokinase (160,000 U) (IC-SK). D-dimer concentrations in 104 patients after IV-APSAC therapy were higher than in 90 patients after IC-SK (mean +/- standard error, 1,009 +/- 60 vs 603 +/- 45, p less than 0.001), but there was no difference in patients with and without reperfusion (1,096 +/- 88 vs 875 +/- 67, p = 0.1 for IV-APSAC, and 587 +/- 48 vs 634 +/- 95, p = 0.6 for IC-SK). The median concentrations before treatment were similar in the IV-APSAC and IC-SK groups (93 and 90 ng/ml, respectively). These were higher than the value in 25 ambulatory control subjects (72 ng/ml) but lower than in 29 post-AMI (6 to 30 hours) patients and in preoperative orthopedic patients (140 ng/ml each). There was no difference in D-dimer concentrations in patients with grade 0 or grade 1 coronary artery occlusion (median 85 vs 90 ng/ml) or in patients with or without ultimate successful reperfusion (median 85 vs 93 ng/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Monitoring of fibrin generation during thrombolytic therapy of acute myocardial infarction with recombinant tissue-type plasminogen activator

Fibrinopeptide A (FPA) is a very sensitive marker of fibrin generation in vivo. Because an imbalance between thrombogenic and thrombolytic forces may be responsible for the failure to recanalize and for reocclusion of coronary arteries, such a marker could be of eminent value during thrombolytic treatment of acute myocardial infarction. Thirty-four consecutive patients with acute myocardial infarction (peak creatine kinase level, 1,869 +/- 1,543 IU/l) were treated with 100 mg recombinant tissue-type plasminogen activator (rt-PA) 3.1 +/- 1.1 hours after onset of chest pain. Angiography 12.5 +/- 6.1 days later revealed an 81% patency rate of the infarct-related vessel. FPA plasma levels (normal, 1.9 +/- 0.5 ng/ml) were 34 +/- 46 ng/ml on admission and 93 +/- 86 ng/ml (538 +/- 674% with respect to each patient's admission level) after 90 minutes of rt-PA infusion (p less than 0.01). In patients without evidence of reocclusion (including three primary failures), FPA levels fell under continuous heparin infusion to 6.7 +/- 9.7 ng/ml (24 +/- 33%, p less than 0.01) within 30 minutes and were 3.1 +/- 2.2 ng/ml (15 +/- 15%, p less than 0.01), 1.6 +/- 1.1 ng/ml (8 +/- 10%, p less than 0.01), and 2.5 +/- 3.0 ng/ml (12 +/- 16%, p less than 0.01) 30 minutes, 9 hours, and 21 hours, respectively, after completion of rt-PA therapy. Five patients sustained intermittent or permanent coronary reocclusion after primary thrombolytic success. Their early postlytic FPA levels (13-51 ng/ml) remained high or increased again despite adequate anticoagulation. FPA allows the monitoring of fibrin generation during acute myocardial infarction and thrombolytic therapy. Despite successful recanalization, fibrin generation is increased under rt-PA administration before anticoagulation. Patients under anticoagulation with postlytic FPA levels less than 5 ng/ml or below their admission value seem to be at low risk of reocclusion for several days. FPA levels that are persistently high or that increase again despite adequate anticoagulation indicate ongoing fibrin generation. However, whether FPA can indeed be considered a useful marker of reocclusion remains to be confirmed in a larger population of patients with acute myocardial infarction.

Effect of low dose acetylsalicylic acid on the frequency and hematologic activity of left ventricular thrombus in anterior wall acute myocardial infarction

In this prospective, randomized, placebo-controlled trial the effect of 100 mg acetylsalicylic acid (ASA) once daily on the incidence, hematologic activity and embolic potential of left ventricular (LV) thrombosis was studied in 100 consecutive patients with a first anterior wall acute myocardial infarction (AMI). Patients were randomized to ASA or placebo less than 12 hours after onset of symptoms. Heparin, 5,000 IU subcutaneously twice daily, was given to all patients during immobilization. Echocardiography was performed less than 24 hours, 48 to 72 hours and 1, 2, and 12 weeks after AMI. LV thrombosis was detected by echocardiography in 30 (33%) of the 92 evaluable patients (15 patients given ASA and 15 given placebo). Indium-111 platelet scintigraphy was done in 17 of the 22 patients with an LV thrombus at the second week echocardiogram. Among 7 ASA-treated patients, 4 had positive images; among 10 placebo patients, 5 had positive images. LV thrombus resolution was noted in 3 of 9 patients with a positive scan and in 5 of 8 patients with a negative platelet scan. In 7 of 10 ASA-treated patients and 5 of 12 placebo-treated patients thrombus resolution was observed (difference not significant). Systemic embolism occurred in 2 patients, both given ASA, during the first week after AMI. Thus, low dose ASA has no effect on the incidence, hematologic activity and embolic potential of LV thrombosis in anterior wall AMI.

Endocardial damage induced by lactate, lowered pH and lactic acid in non-ischemic beating hearts

The left ventricular lumen of isolated perfused beating hearts was perfused for up to 8 h with either Krebs Henseleit buffer (KHB, pH 7.4), KHB including 33 mumol/ml of lactic acid at pH 7.4 or 6.4, or with KHB including hydrochloric acid to reduce the pH to 6.4. Scanning and transmission electron microscopy showed that whereas control hearts maintained an intact endocardium, those groups exposed to increased concentrations of lactate, hydrogen ions or both, developed endothelial cell separation and exfoliation with exposure first of basal lamina and then of endocardial collagen. The underlying myocytes also showed evidence of irreversible cell injury. The extent and severity of damage was greater in hearts exposed to lactic acid than to either lactate or lowered pH alone. These findings suggest that the increased concentrations of metabolites which accumulate in developing myocardial infarcts can diffuse through and damage the endocardium in ways which are likely to predispose in vivo to the development of mural thrombosis.

Prospective two-dimensional echocardiographic evaluation of left ventricular thrombus and embolism after acute myocardial infarction

To determine whether two-dimensional echocardiography can identify patients with left ventricular thrombus after myocardial infarction who are prone to embolism, clinical and echocardiographic variables in 541 patients with a first infarction between 1979 and 1983 were studied prospectively. The first echocardiogram showed definite thrombus in 115 patients (Group 1, 21%) and no thrombus in 426 (Group 2, control). In Group 1, 27 patients (23%) had clinical evidence of systemic embolism related to the thrombus before referral (Group 1a) and 88 did not (Group 1b); these two groups were similar in age, gender and infarct location, but more Group 1a patients were within 1 month of the acute infarction. In both Groups 1a and 1b, the thrombus was found in apical views over asynergic zones, with no difference (p greater than 0.05) between the two groups in the size (average area from two views being 5.3 versus 4.5 cm2), type (protruding in apical views 30% versus 27%), location (apical 83% versus 86%; septal 11% versus 11%; posterior 4% versus 2%), extent of asynergy (31% versus 33%) and ejection fraction (33% versus 34%). However, the frequency of anticoagulant therapy was less (26% versus 63%, p less than 0.005), adjacent hyperkinesia greater (100% versus 49%, p less than 0.005) and thrombus mobility greater (81% versus 19%, p less than 0.005) in Group 1a than in Group 1b. Serial echocardiograms revealed a decreased size of the thrombus by 6 months in both Groups 1a and 1b, and little or no trace in 85% by 24 months. Thus, ventricular thrombus size, location and protrusion in apical views on echocardiography did not correlate with embolism. In contrast, thrombus mobility, the presence of adjacent hyperkinesia and thrombus protrusion assessed in multiple views appeared to be strong discriminators of thrombus prone to embolism. These echocardiographic features might provide a guide for the duration of anticoagulant therapy.

Comparison of high-dose with low-dose subcutaneous heparin to prevent left ventricular mural thrombosis in patients with acute transmural anterior myocardial infarction

We performed a double-blind randomized trial comparing high doses of subcutaneous heparin (12,500 units every 12 hours) with low doses (5000 units every 12 hours) for 10 days in the prevention of left ventricular mural thrombosis in 221 patients with acute anterior myocardial infarction. Left ventricular mural thrombosis was observed by two-dimensional echocardiography on the 10th day after infarction in 10 of 95 patients (11 percent) in the high-dose group and in 28 of 88 patients (32 percent) in the low-dose group (P = 0.0004). One patient in the high-dose group and four in the low-dose group had nonhemorrhagic strokes (P = 0.17). One patient in the low-dose group had a fatal pulmonary embolism. There was no difference in the frequency of hemorrhagic complications, which occurred in six patients in the high-dose group and four in the low-dose group. The mean (+/- SEM) plasma heparin concentration was 0.18 +/- 0.017 U per milliliter in the high-dose group and 0.01 +/- 0.005 U per milliliter in the low-dose group (P less than 0.0001). In the high-dose group, the mean plasma heparin concentration was 0.10 +/- 0.029 U per milliliter among patients with abnormal two-dimensional echocardiograms, as compared with 0.19 +/- 0.019 U per milliliter among patients with normal echocardiograms (P = 0.01). We conclude that heparin administered subcutaneously in a dosage of 12,500 units every 12 hours to patients with acute anterior transmural myocardial infarction is more effective than a lower dosage (5000 units every 12 hours) in preventing left ventricular mural thrombosis.