Predictors of left atrial thrombus resolution in patients with mitral stenosis planned for percutaneous transvenous mitral commissurotomy(PTMC)
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Date
2019-12
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SCTIMST
Abstract
Mitral stenosis (MS) is a common finding in Rheumatic Heart Disease (RHD). The current
management of symptomatic mitral stenosis is Percutaneous Transvenous Mitral
Commissurotomy (PTMC) unless it is contraindicated. The presence of Left Atrial Thrombus
(LAT), however, is generally considered a contraindication to PTMC, leaving the open
surgery as the treatment option.
Left atrial thrombus occurs frequently in patients with Rheumatic Mitral Stenosis1
.Most of
Left Atrial thrombus occurs in Left Atrial Appendage(LAA)2. The association of LAT in
patients with MS and atrial fibrillation (AF) is well known3
. But it also occurs in patients
with sinus rhythm (SR). And patients in Sinus Rhythm (SR) of rheumatic mitral stenosis
were also noted to have larger LAA and poorer LAA contractile function3,4.This enhances
stagnation and thrombus formation in the Left atrial appendage or Left atrium. The presence
of thrombus increases the risk of systemic and peripheral embolism and it is a relative
contraindication for PTMC. Framingham study showed 17 fold increase in risk of stroke for
patients with AF and MS5. The reported incidence of LAT in severe Rheumatic MS is
between 10% and 25%6,7,8
. Various studies have shown that Transesophageal
Echocardiography(TEE) identifies Left atrial thrombus better than Transthoracic
Echocardiography(TTE). The presence of LAT in patients with mitral Stenosis may alter the
therapeutic approaches to the disease. In some circumstances, complete resolution of LAT
can be achieved with oral anticoagulant therapy (OAC), allowing patients to undergo PTMC
safely. Knowing the likelihood of LAT disappearance would help the physician to decide
whether to proceed with surgical repair or to continue oral anticoagulation until LAT
resolution and then to perform PTMC. The current management of severe MS is PTMC
unless contraindicated. After complete resolution of LAT following adequate anticoagulation,2
these patients with severe MS can undergo PTMC without any added risk. Especially a model
would help in predicting the likelihood of LA thrombus resolution, and hence, the treatment
plan can be altered accordingly. Hence it is very essential to develop a model to identify
patients who would respond to Oral anticoagulants on short term.