Severe mitral regurgitation may prevent mural thrombus formation within the left ventricle with systolic dysfunction

Risk Factors for Left Ventricular Thrombus Formation in Patients with Dilated Cardiomyopathy

BACKGROUND

 Left ventricular thrombus (LVT) is a common complication of dilated cardiomyopathy (DCM), causing morbidity and mortality.

METHODS

 This study retrospectively analyzed patients with DCM from January 2002 to August 2020 in Beijing Anzhen Hospital. Clinical characteristics were compared between the LVT group and the age and sex 1:4 matched with the LVT absent group. The receiver operator characteristic (ROC) curve was plotted to evaluate the diagnostic value of D-dimer predicting LVT occurrence in DCM.

RESULTS

 A total of 3,134 patients were screened, and LVT was detected in 72 (2.3%) patients on echocardiography. The patients with LVT had higher D-dimer, fibrinogen, and lower systolic blood pressure than those without LVT. The ejection fraction (EF) was lower and left ventricular end-systolic diameter was larger in the LVT group. Severe mitral regurgitation (MR) was more common in the LVT absent groups. The prevalence of atrial fibrillation was lower in the LVT group. The ROC curve analysis yielded an optimal cut-off value of 444 ng/mL DDU (D-dimer units) for D-dimer to predict the presence of LVT. Multivariable binary logistic regression analysis revealed that EF (OR = 0.90, 95% CI = 0.86-0.95), severe MR (OR = 0.19, 95% CI = 0.08-0.48), and D-dimer level (OR = 15.4, 95% CI = 7.58-31.4) were independently associated with LVT formation.

CONCLUSION

 This study suggested that elevated D-dimer levels (>444 ng/mL DDU) and reduced EF were independently associated with increased risk of LVT formation. Severe MR could decrease the incidence of LVT.

Does mitral regurgitation reduce the risks of thrombosis in atrial fibrillation and flutter?

AIMS

Blood stasis is the main cause of left atrial thrombosis (LAT) in atrial tachyarrhythmias. The high-velocity flow inside the left atrium, due to mitral valve regurgitation, may prevent clot formation but the topic has never been investigated in large-scale studies. The aim of our study was to evaluate whether the presence and degree of mitral regurgitation have a protective role against LAT risk.

METHODS

A total of 1302 consecutive adult patients with paroxysmal or persistent atrial fibrillation or flutter undergoing cardioversion, submitted to transesophageal echocardiography, were retrospectively enrolled in the study. The study population was divided into three groups according to the mitral regurgitation degree: absent, mild-to-moderate and severe.

RESULTS

Among 1302 patients enrolled in the study, patients without mitral regurgitation were 248 (19%), those with mild-to-moderate 970 (75%), whereas 84 had severe mitral regurgitation (6%). LAT incidence was significantly lower in patients with severe mitral regurgitation compared with those with mild-to-moderate (mitral regurgitation) (2.4 vs. 8.9%, P < 0.05), and similar to subjects without mitral regurgitation (2.4%).

CONCLUSION

Despite patients with severe regurgitation having clinical and echo characteristics predisposing to LAT (higher age, heart failure, higher atrial size, lower ventricular function) thrombosis prevalence was significantly lower than for those with mild-to-moderate mitral regurgitation. The percentage of LAT in severe mitral regurgitation cases was very low and similar to that of cases without regurgitation which were characterized by lower age, normal left ventricular function or other risk factors, reinforcing the hypothesis of a protecting role against atrial thrombosis of mitral regurgitation.

Clinical Characteristics and Risk Factors of Left Ventricular Thrombus after Acute Myocardial Infarction: A Matched Case-control Study

Background:

Left ventricular thrombus (LVT) is reported to be a common complication in acute myocardial infarction (AMI) patients. And it has the potential to cause systemic embolism. This retrospective study was to present the current situation of LVT in clinical practice, as well as to evaluate the clinical characteristics and the risk factors of LVT after AMI.

Methods:

LVT cases (n = 96) were identified from 13,732 AMI (non-ST elevation myocardial infarction was excluded) patients in Fuwai Hospital's electronic medical records system from January 2003 to January 2013. The controls (n = 192) were gender- and age-matched AMI patients without LVT during this period. A conditional logistic regression (fitted by the Cox model) was performed to identify the independent risk factors.

Results:

The incidence of LVT after AMI was 0.7%. Univariate analysis indicated that the anterior myocardial infarction (especially extensive anterior myocardial infarction), lower left ventricular ejection fraction (LVEF), LVEF ≤40%, severe regional wall motion abnormalities (RWMA), pericardial effusion, and left ventricular aneurysm were all related to LVT after AMI. The independent risk factors obtained from the conditional logistic regression analysis were lower LVEF (odds ratio (OR) = 0.891, 95% confidence interval (CI): 0.828–0.960), extensive anterior myocardial infarction (OR = 6.403, 95% CI: 1.769–23.169), severe RWMA (OR = 7.348, 95% CI: 1.323–40.819), and left ventricular aneurysm (OR = 6.955, 95% CI: 1.673–28.921).

Conclusions:

This study indicated that lower LVEF, extensive anterior myocardial infarction, severe RWMA, and left ventricular aneurysm were independent risk factors of LVT after AMI. It also suggested that further efforts are needed for the LVT diagnosis after AMI in clinical practice.

Dangerous liaison: successful percutaneous edge-to-edge mitral valve repair in patients with end-stage systolic heart failure can cause left ventricular thrombus formation

AIMS

To evaluate the characteristics and clinical outcome of patients with new formation of left ventricular (LV) thrombus after percutaneous edge-to-edge mitral valve repair.

METHODS AND RESULTS

Between 2009 and 2012 we intended to treat 150 patients with severe mitral regurgitation (MR) with percutaneous edge-to-edge mitral valve repair in our centre. Post-procedural transthoracic echocardiographic examinations scheduled during the hospital stay revealed the new formation of LV thrombi in three out of 150 patients. All three patients suffered from end-stage systolic heart failure with a LV ejection fraction (LVEF) below 20% and were successfully treated in terms of MR reduction (reduction of at least two MR grades). No thrombus formation was observed in patients with a LVEF >20% treated in our centre (a total of 136 patients). The frequency of new LV thrombus formation in the cohort of patients with a LVEF ≤20% treated in our centre was 21% (three out of 14 patients).

CONCLUSIONS

New formation of LV thrombus was detected in patients with severely depressed LVEF (≤20%) after successful reduction of MR following percutaneous edge-to-edge mitral valve repair. This phenomenon could be a play of chance, but percutaneous edge-to-edge mitral valve repair using the MitraClip¨ system is a new procedure. Special care is needed when performing new procedures, and the unexpected post-procedural finding of LV thrombus formation in approximately 20% in this cohort is worth reporting.

A single-center experience with intracardiac thrombosis in children with dilated cardiomyopathy

Intracardiac thrombosis in patients with a dilated cardiomyopathy can be life threatening. This study investigated the incidence, risk factors, and outcome of intracardiac thrombosis in children with dilated cardiomyopathy. A retrospective review of the clinical records was performed in 83 children with dilated cardiomyopathy diagnosed from January 1995 to December 2008. Intracardiac thrombi were detected in 5 patients (6.0%). The intracardiac thrombi were found mainly in the left ventricle (n = 3). One patient had a thrombus in the left atrium at the time of diagnosis, and a right ventricular thrombus was found in 1 patient with unrepaired ventricular septal defect complicated by pulmonary hypertension. Intracardiac thrombosis developed during rapid deterioration of ventricular function, and all patients had a poor ejection fraction of the left ventricle. All patients were treated with heparinization, and thrombectomy was performed in 1 patient. Three patients achieved complete resolution of the thrombus without further embolic complications. Careful evaluation and aggressive anticoagulation are necessary for the prevention of intracardiac thrombosis in children with poor ventricular function, especially during rapid deterioration of ventricular function.

A Model Incorporating Some of the Mechanical and Biochemical Factors Underlying Clot Formation and Dissolution in Flowing Blood

Multiple interacting mechanisms control the formation and dissolution of clots to maintain blood in a state of delicate balance. In addition to a myriad of biochemical reactions, rheological factors also play a crucial role in modulating the response of blood to external stimuli. To date, a comprehensive model for clot formation and dissolution, that takes into account the biochemical, medical and rheological factors, has not been put into place, the existing models emphasizing either one or the other of the factors. In this paper, after discussing the various biochemical, physiologic and rheological factors at some length, we develop a model for clot formation and dissolution that incorporates many of the relevant crucial factors that have a bearing on the problem. The model, though just a first step towards understanding a complex phenomenon, goes further than previous models in integrating the biochemical, physiologic and rheological factors that come into play.