Prognostic significance and natural history of left ventricular thrombi in patients with acute anterior myocardial infarction: a two-dimensional echocardiographic study

Relation between myocardial infarct location and stroke

OBJECTIVES

We sought to compare the likelihood of stroke in patients with anterior versus nonanterior myocardial infarction.

BACKGROUND

The association between anterior infarction and left ventricular thrombus has led to the assumption that embolization from thrombi is an important cause of stroke in patients with anterior infarction. We hypothesized that if anterior infarction is a cause of left ventricular thrombi, the number of strokes should be disproportionately higher in patients with anterior than nonanterior infarction.

METHODS

We performed a retrospective analysis of 2,466 patients randomized from day 3 to day 15 after infarction as part of a multicenter placebo-controlled study of diltiazem to prevent cardiac death or myocardial infarction. Any acute focal cerebral disorder resulting in localizing findings characterized as a stroke or transient ischemic attack was considered an event.

RESULTS

Of 91 events during a follow-up period of 12 to 52 months, 23 (3.2%) occurred in 724 patients with an anterior and 68 (3.9%) in 1,742 patients with a nonanterior myocardial infarction (relative risk 0.81; 95% confidence interval 0.51 to 1.30). Power analysis revealed that the negativity of the study was not the result of inadequate sample size. Life table analysis showed no difference in cumulative event rate (p = 0.42) according to site of infarction. Cox regression analysis showed that of 10 clinical covariates, only systolic blood pressure was predictive of stroke (p < 0.001). The use of warfarin did not contribute to the model. Finally, the addition of site of infarction (anterior vs. nonanterior) did not contribute significantly to the Cox model.

CONCLUSIONS

Although there is a significant incidence of stroke after acute myocardial infarction, there is no relation between the occurrence of stroke and site of infarction. These data do not support the presumed causal relation between anterior myocardial infarction, thrombus and stroke.

Improved echocardiographic detection and characterization of left ventricular apical thrombi with a 5.0 MHz short-focus transducer

Transthoracic echocardiography is a frequently used technique for detecting ventricular thrombi. This study compares the usefulness of a 5.0 MHz short focal length transducer (5-short) with standard frequency (2.5 or 3.5 MHz) transducers for the detection of left ventricular thrombi. In addition, the effect of body habitus on study quality was evaluated. A consecutive series of 101 patients sent for echocardiographic imaging with the diagnosis of myocardial infarction, dilated cardiomyopathy, or recent suspected embolic event were imaged in the apical four-chamber, apical long-axis, and apical two-chamber views with a standard transducer and also with the 5-short. Out of this group, 16 apical thrombi were identified, six with the 5-short only, three with standard transducers only, and seven by both techniques. The areas of the seven thrombi detected by both transducers were consistently larger when measured on 5-short images compared with standard transducer images (4.6 +/- 2.3 vs 3.7 +/- 2.3 cm2, p = 0.02). In the three studies positive only with the standard transducers, the 5-short demonstrated only prominent trabeculae but no thrombus. The studies positive only with the 5-short had significantly smaller calculated thrombi areas than those visualized by the standard transducers (1.6 +/- 1.2 vs 4.2 +/- 2.1 cm2, p = 0.02). No thrombus was detected by either technique in a normally contracting left ventricular apex. There were significantly fewer studies having near-field artifact when performed by the 5-short compared with those performed with standard transducers (14/101 vs 40/101, p = 0.00004).(ABSTRACT TRUNCATED AT 250 WORDS)

Embolic potential, prevention and management of mural thrombus complicating anterior myocardial infarction: a meta-analysis

OBJECTIVES

The management of mural thrombus complicating acute anterior myocardial infarction remains controversial in part because of the small size of studies on this topic. We performed a meta-analysis of published studies to address three questions: 1) What is the embolic risk of mural thrombi after myocardial infarction? 2) What is the impact of systemic anticoagulation in reducing the embolic risk of mural thrombi? 3) What is the impact of systemic anticoagulation, thrombolytic therapy and antiplatelet therapy in preventing mural thrombus formation?

METHODS

Studies were identified by a computerized and manual search and were included if they were published in manuscript form in the English-language literature. Pooling of data was performed by calculating the Mantel-Haenszel odds ratio and an event rate difference by the method of DerSimonian and Laird.

RESULTS

The odds ratio for increased risk of emboli in the presence of echocardiographically demonstrated mural thrombus (11 studies, 856 patients) was 5.45 (95% confidence interval [CI] 3.02 to 9.83), and the event rate difference was 0.09 (95% CI 0.03 to 0.14). The odds ratio of anticoagulation versus no anticoagulation in preventing embolization (seven studies, 270 patients) was 0.14 (95% CI 0.04 to 0.52) with an event rate difference of -0.33 (95% CI -0.50 to -0.16). The odds ratio of anticoagulation versus control in preventing mural thrombus formation (four studies, 307 patients) was 0.32 (95% CI 0.20 to 0.52), and the event rate difference was -0.19 (95% CI -0.09 to -0.28). The odds ratio for thrombolytic therapy in preventing mural thrombus (six studies, 390 patients) was 0.48 (95% CI 0.29 to 0.79) with an event rate difference of -0.16 (95% CI 0.10 to -0.42), whereas for antiplatelet agents (two studies, 112 patients) the odds ratio was 1.43 (95% CI 0.04 to 56.8) with an event rate difference of 0.16 (95% CI -0.20 to 0.52).

CONCLUSIONS

This analysis supports the hypotheses that 1) mural thrombus after myocardial infarction poses a significantly increased risk of embolization, 2) the risk of embolization is reduced by systemic anticoagulation, and 3) anticoagulation can prevent mural thrombus formation. Thrombolytic therapy may prevent mural thrombus formation, but evidence for a similar benefit of antiplatelet therapy is lacking.

Echocardiography in the evaluation of cardiac sources of emboli: the role of transthoracic echocardiography

Cardioembolism is responsible for a significant number of systemic emboli including approximately 15% of all ischemic strokes. Transthoracic echocardiography has contributed to the understanding of cardioembolism and has been used to detect specific and potential cardiac sources of systemic emboli and risk stratify patients with specific clinical findings for subsequent cardiovascular events. Findings from transthoracic echocardiography indicate that stasis is an important prerequisite for intracardiac thrombosis while reversal of stasis and thrombolysis appear operative in embolism of existing thrombus. Transthoracic echocardiography allows a sensitive and specific noninvasive means to detect left ventricular thrombus, valvular vegetation, and intracardiac tumor, lesions that are directly responsible for cardioembolism. Transthoracic echocardiography can also detect lesions that could potentially contribute to cardioembolism but are not specific causes. Examples of these potential lesions include mitral valve prolapse, patent foramen ovale, and interatrial septal aneurysm. Finally, population-based studies and prospective clinical trials have indicated that the results of transthoracic echocardiography have predictive value for subsequent cardiovascular events and hence provide a means for stratification of patients at risk for cardioembolism. The latter is most notable for the group of patients with nonvalvular atrial fibrillation where left ventricular dysfunction and increased left atrial size are independent predictors for subsequent stroke.

Use of echocardiography in detecting cardiac sources of embolus

Up to 20% of all ischemic strokes are felt to be the result of emboli from the heart. High resolution transthoracic (TTE) and transesophageal (TEE) echocardiography have been the principal diagnostic tools for detecting associated cardiac abnormalities and for guiding medical and surgical approaches to these patients. In addition to identifying the precise location and morphological characteristics of intracardiac masses, echocardiography has improved our ability to predict embolic potential of these masses. Specific cardiac lesions that are predisposed to stroke and are readily identifiable by echocardiography include: cardiac thrombi, valvular vegetations, cardiac tumors, aortic atheroma, atrial septal aneurysm, and regional left ventricular wall abnormalities. Careful interrogation of patients with cerebrovascular accidents has identified a potential cardiac source of embolus in approximately 30%. This is largely due to the advent of TEE, which has provided much better assessment of posterior cardiac chambers including left atrium and left atrial appendage. Use of TEE in identifying a cardiac source of embolus is indicated in patients with stroke who are young, have no apparent cerebrovascular disease, or have recurrent embolic events. Echocardiography is an essential diagnostic tool in evaluating patients with a suspected cardiac source of embolus. TTE and TEE provide invaluable information regarding the majority of cardiac sources of embolus.

Left ventricular thrombosis and arterial embolism in acute anterior myocardial infarction

To study left ventricular thrombus (LVT) formation and arterial embolism (AE), 106 consecutive patients with a first acute anterior myocardial infarction (AAMI) underwent two-dimensional echocardiography before discharge. Repeated assessments for detection of AE were performed. Patients were non-randomly allocated to either no heparin, low-dose heparin or high-dose heparin. LVT was found in 25 (26.9%) of 93 patients with technically satisfactory echocardiograms. Left ventricular (LV) wall motion impairment (P = 0.0017) and treatment with either heparin or low-dose heparin (P = 0.0019) were independent predictors of LVT formation. AE, all strokes, occurred in 10 patients (9.4%) and was strongly associated with high age (P = 0.0013). In conclusion, LVT and AE are frequent complications to AAMI. LV wall motion impairment predisposes for LVT and low-dose heparin seems not to prevent these complications.

Usefulness of transesophageal echocardiography in identifying small left ventricular apical thrombus

OBJECTIVES

The aim of this study was to determine whether transesophageal echocardiography could clarify the nature of equivocal echodense structures in the left ventricular apical region frequently found on transthoracic echocardiography by directing the ultrasound beam from the left ventricular base to the apex and achieving better image quality.

BACKGROUND

Transthoracic echocardiography often reveals an echogenic structure suggesting thrombus in the left ventricular apical region because of limited near-field resolution and echo vibration artifact in apical views.

METHODS

Thirty-six patients with coronary artery disease or dilated cardiomyopathy who had apical wall motion abnormalities and equivocal transthoracic echodense structures were studied with transesophageal echocardiography using special manipulation of the transesophageal probe for adequate imaging of the apical region. Left ventricular thrombus was defined when echogenic structures with a clearly delineated margin adjacent to but distinct from the endocardium were observed in at least two different tomographic views in the four-chamber and left ventricular long-axis views during both systole and diastole.

RESULTS

Left ventricular thrombus (mean size 1.3 +/- 0.7 cm2) was defined by transesophageal echocardiography in 19 (53%) of 36 patients with suspected thrombus on transthoracic echocardiography in the four-chamber or left ventricular long-axis view. Heavy trabeculation or extremely high echo reflection, or both, was observed in the apical region in 12 patients (33%). No extra structures in the apical region were found in five patients. In 19 patients with transesophageal echocardiographically defined thrombus, 6 patients (31%) experienced arterial embolic events before the transesophageal procedure. In contrast, none of 17 patients without transesophageal echocardiographically defined thrombi had systemic embolism (p < 0.03).

CONCLUSIONS

1) Transesophageal echocardiography is useful in identifying left ventricular apical thrombus in patients with unclear echogenic structures on transthoracic apical images; and 2) the high incidence of arterial embolism in patients with transesophageal echocardiographically detected left ventricular thrombus indicates the clinical importance of such thrombus.

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.

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).

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.

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)

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.

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)

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.

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.

Surgical removal of a mobile, pedunculated left ventricular thrombus: report of 4 cases

During an 11-month period, 4 patients underwent surgical removal of a mobile, pedunculated left ventricular thrombus. All 4 patients had a history of myocardial infarction. Two of the 4 patients had systemic emboli, and in the 2 others, the ventricular thrombi were removed to prevent emboli. The thrombus was removed during the acute phase of myocardial infarction in 2 patients and one and two years, respectively, following the infarct in the remaining 2 patients. Concomitant coronary artery bypass grafting was performed in 3 patients. There were no early or late deaths, and none of the patients had clinical or echocardiographic evidence of recurrent thrombi or emboli at follow-up 3 to 15 months later. These results indicate that left ventricular thrombectomy might be an effective treatment for patients with mobile, pedunculated, left ventricular thrombi. However, additional experience is required to compare surgical and medical treatment.

Left ventricular thrombus formation after first anterior wall acute myocardial infarction

The characteristics of the left ventricle and coronary arteries associated with left ventricular (LV) thrombus in patients with recent anterior acute myocardial infarction were defined. Of 77 patients studied, 35 (46%) had LV thrombi. The presence of LV thrombus was not correlated to the extent of coronary artery disease. The frequency of LV thrombus progressively increased with groups of increasing wall motion abnormality as determined by the extent of akinesia and dyskinesia (%AD) (%AD 0 to 14, thrombus present in 3 of 16 [19%], %AD 15 to 29, thrombus in 8 of 27 [30%]; %AD greater than or equal to 30%, thrombus in 24 of 34 [71%]; p less than 0.001) and with increasingly severe degrees of early ventricular shape change (normal or mildly abnormal contour, 16% with thrombus; moderately abnormal contour, 36% with thrombus; severely abnormal contour, 70% with thrombus; p less than 0.001). Patients with thrombi had higher diastolic (249 +/- 55 vs 225 +/- 48 ml; p less than 0.05) and systolic (158 +/- 48 vs 120 +/- 45 ml; p less than 0.001) volumes than patients without thrombi, respectively. A stepwise discriminant analysis identified ejection fraction, extent of early shape change and LV end-diastolic pressure as independent correlates of LV thrombus after acute myocardial infarction.

Thromboembolic splenic infarction

Splenic infarction occurs as a consequence of systemic thromboembolization in association with several cardiovascular disorders. We describe a case of splenic infarction in a patient who had paroxysmal atrial fibrillation after aortic valve replacement. In an autopsy series of 96 consecutive cases of splenic infarction, only 10% had been suspected clinically even though the splenic infarctions had contributed substantially to morbidity and mortality in 44% of the cases. Thromboembolic causes were responsible for the splenic infarcts in 67% of the cases, and concomitant infarcts in other organ systems were found in 62%. Embolization of atheromatous debris from the aorta, thrombotic elements from the left ventricle (in dilated cardiomyopathy and acute myocardial infarction), and vegetations from infected valves are the most common settings in which thromboembolic splenic infarcts are noted. The clinical picture associated with splenic infarction is typically nonspecific; manifestations may include fever, tachycardia, and left-upper-quadrant tenderness. Computed tomographic scanning and, to a lesser degree, ultrasonography are the imaging techniques of choice for diagnosing splenic infarction.

Early echocardiographic detection of right-sided intracardiac thrombus

A right atrioventricular thrombus occurring as a consequence of a central venous catheter was echocardiographically detected in an asymptomatic 62-year-old man after an acute myocardial infarction. Prompt surgical removal of the thrombus removed the potential for pulmonary embolism.