|Year : 2021 | Volume
| Issue : 3 | Page : 190-194
Early Assessment of Left Atrial Appendicular Velocities in Patients Undergoing Balloon Mitral Valvuloplasty
Subramanyam Kasamsetty, Manohar J. Suranagi, Rangaraj Ramalingam, K. S. Subramani
Department of Cardiology, Sri Jayadeva Institute of Cardiovascular Sciences and Research, Bengaluru, Karnataka, India
|Date of Submission||01-Oct-2020|
|Date of Acceptance||18-Dec-2020|
|Date of Web Publication||06-Jul-2021|
Dr. Subramanyam Kasamsetty
Associate Prof in Cardiology, Sri Jayadeva Institute of Cardiiovascular Sciences and Research, Bannerghatta Road, Jayanagar, 9th Block, Bengaluru - 560 069, Karnataka
Source of Support: None, Conflict of Interest: None
Introduction: Peripheral embolism is a major complication in patients with mitral stenosis. Several studies have suggested a relation between a decrease in left atrial appendage (LAA) function and more frequent thromboembolic events of cardiac origin. This study was conducted to assess LAA function before and after percutaneous transvenous mitral commissurotomy (PTMC) using transesophageal echocardiography and to determine factors related to improvement in LAA function. Methods: Fifty consecutively admitted patients with significant mitral stenosis undergoing PTMC were included in the study. All patients underwent transthoracic and transesophageal echocardiographic examination, including the study of LAA velocities, before and 48 h after PTMC. Results: PTMC resulted in a twofold increase in the mitral valve area and no severe mitral regurgitation occurred. The mean mitral valve orifice area increased from 0.9 ± 0.3 cm2 to 1.84 ± 0.22 cm2. There was a decrease in the mean left atrial pressure from 26 ± 8.6 to 12 ± 2.8 mmHg. PTMC also resulted in a significant improvement in the LAA flow velocities, with the anterograde component of the flow increasing from 19.56 ± 9.48 cm/s to 33.10 ± 14.01 cm/s. There was also a significant resolution of the spontaneous echo contrast in the left atrium. Conclusion: There is a significant improvement in the LAA velocities following PTMC and a significant decrease in the spontaneous echo contrast, potentially leading to a lower risk of embolism.
Keywords: Balloon mitral valvuloplasty, left atrial appendicular velocities, mitral valve orifice area, percutaneous mitral commissurotomy
|How to cite this article:|
Kasamsetty S, Suranagi MJ, Ramalingam R, Subramani KS. Early Assessment of Left Atrial Appendicular Velocities in Patients Undergoing Balloon Mitral Valvuloplasty. J Indian Acad Echocardiogr Cardiovasc Imaging 2021;5:190-4
|How to cite this URL:|
Kasamsetty S, Suranagi MJ, Ramalingam R, Subramani KS. Early Assessment of Left Atrial Appendicular Velocities in Patients Undergoing Balloon Mitral Valvuloplasty. J Indian Acad Echocardiogr Cardiovasc Imaging [serial online] 2021 [cited 2022 Jan 27];5:190-4. Available from: https://www.jiaecho.org/text.asp?2021/5/3/190/320783
| Introduction|| |
Peripheral embolism is a major complication in patients with mitral stenosis, and most frequently results from the migration of thrombi developing in the left atrial appendage (LAA)., Several studies have suggested a relation between a decrease in LAA function and more frequent thromboembolic events of cardiac origin.,,,,,
Since 1984, percutaneous transvenous mitral commissurotomy (PTMC) has been demonstrated to be a safe and effective procedure for severe mitral stenosis.,,, A successful procedure results in the disappearance of spontaneous echo contrast or a decrease in its intensity, suggesting a beneficial effect on left atrial (LA) blood stasis.
The present study assesses LAA function before and after PTMC using transesophageal echocardiography and determines factors related to improvement in LAA function.
| Methods|| |
Fifty consecutively admitted patients were included in this study.
Patients with mitral stenosis with mitral valve orifice area (MVOA) of <1.0–1.2 cm2, sinus rhythm, and New York Heart Association (NYHA) functional class II or III were eligible for inclusion in this study. Those with >moderate mitral regurgitation (MR), LA thrombus, aortic valve involvement, and postcytomegalovirus status and pregnant patients were excluded from the study.
All patients underwent transthoracic and transesophageal echocardiographic examination, including the study of LAA velocities, before and 48 h after PTMC using the same protocol. Examinations were performed with commercially available equipment-Philips Sonos 5500, using an adult echocardiography probe (2.5 MHz).
Mitral valve area was calculated from planimetry in the parasternal short-axis view [Figure 1]. The suitability of the valve morphology was determined using the Wilkins score. Mitral valve gradients were measured using continuous-wave Doppler [Figure 2]. The LA diameter was measured in the parasternal long-axis view.
|Figure 1: Significantly reduced mitral valve orifice area in a patient with mitral stenosis prior to percutaneous transvenous mitral commissurotomy|
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|Figure 2: Transmitral pressure gradient in a patient with mitral stenosis prior to percutaneous transvenous mitral commissurotomy|
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Transesophageal examinations were performed with the same echocardiography machine, using a 7.5 MHz uniplanar transesophageal transducer. The patients were kept in the left lateral decubitus position and received oral anesthesia with lignocaine. The introduction of the transesophageal probe and acquisition of the images was carried out through a conventional technique. Spontaneous echo contrast (SEC) was assessed by the transesophageal approach using appropriate gain settings [Figure 3] and [Figure 4]. SEC was graded according to the method described by Fatkin et al.:
|Figure 3: Spontaneous echo contrast prior to percutaneous transvenous mitral commissurotomy|
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|Figure 4: Spontaneous echo contrast following percutaneous transvenous mitral commissurotomy (same patient as in Figure 3)|
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0 = none (absence of echogenicity)
1 + = Mild (minimal echogenicity located in the LAA or sparsely distributed in the main cavity of the left atrium)
2 + = Mild to moderate (more dense swirling pattern than 1 + but with similar distribution; detectable without increased gain settings)
3 + = Moderate (dense swirling pattern in the LAA, generally associated with somewhat lesser intensity in the main cavity, and may fluctuate in intensity but detectable constantly throughout the cardiac cycle)
4 + = Severe (intense echo density and very slow swirling patterns in the LAA, usually with similar density in the main cavity).
The LAA velocities were recorded using pulsed-wave Doppler. The sample volume was positioned inside the LAA cavity, approximately 1 cm below the LAA opening, in the middle third of LAA with no wall artifacts [Figure 5] and [Figure 6]. LAA flow profiles were obtained in longitudinal planes and low wall filters were always used and the sample volume size was 3 mm. The anterograde (wave A) and retrograde (wave R) LAA flow velocities were measured.,
|Figure 5: Left atrial appendage flow velocities prior to percutaneous transvenous mitral commissurotomy|
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|Figure 6: Left atrial appendage flow velocities after percutaneous transvenous mitral commissurotomy (same patient as in Figure 5)|
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All patients underwent PTMC using the transvenous anterograde Inoue technique. A hemodynamic study was performed on each patient before and after the procedure. Mean LA pressures were recorded before and after the procedure. MVOA and mitral valve gradients were measured by two-dimensional echocardiography.
| Results|| |
In the present study, there were 19 (38%) men and 31 women and the age of presentation ranged from 20 to 45 years with a mean age of 32.5 ± 12.5 years [Table 1]. Thirty-six (72%) patients were in functional class II and 14 patients were having class III symptoms. All the patients were in sinus rhythm [Table 1]. [Table 2] summarizes baseline echocardiography parameters in the study subjects.
Percutaneous mitral commissurotomy resulted in a twofold increase in the MVOA and no severe MR occurred. The mean MVOA increased from 0.9 ± 0.3 cm2 to 1.84 ± 0.22 cm2 [Figure 7]. There was a decrease in the mean LA pressure from 26 ± 8.6 to 12 ± 2.8 mmHg. There was a decrease in the mean pulmonary artery systolic pressure from 50 ± 12 mmHg to 40 ± 10 mmHg [Table 3]. The mean mitral valve gradient decreased from 22 ± 4.6 mmHg to 9 ± 2.1 mmHg [Figure 8]. Fifteen patients had grade I SEC which disappeared after dilatation. Nine patients with grade II SEC had grade I SEC after the procedure.
|Table 3: Echocardiographic parameters before and after mitral commissurotomy|
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|Figure 7: Commissural splitting with improved mitral valve opening secondary to percutaneous transvenous mitral commissurotomy (same patient as in Figure 1)|
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|Figure 8: Transmitral pressure gradient after percutaneous transvenous mitral commissurotomy (same patient as in Figure 2)|
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Left atrial appendage Doppler flow pattern was characterized by a biphasic wave with an alternating positive wave, occurring after the start of the electrocardiographic P wave and corresponding to active emptying of the LAA, and a negative wave corresponding to passive filling of the LAA. There was a significant improvement in the LAA appendage velocities post procedure [Figure 6]. The anterograde component of the flow increased from a mean of 19.56 ± 9.48 cm/s to 33.10 ± 14.01 cm/s. The retrograde component of the flow increased from a mean of 24.88 ± 10.66 cm/s to 35.01 ± 16.13 [Table 4].
|Table 4: Left atrial appendage flow velocities and spontaneous echo contrast assessed using transesophageal echocardiography|
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| Discussion|| |
This study objectively shows the functional changes in the LAA induced by the relief of the LA hypertension after PTMC in patients with mitral stenosis. It also highlights the importance of transesophageal echocardiography as an especially useful technique in the evaluation of these aspects, which is otherwise extremely difficult to demonstrate using other diagnostic methods.
In patients with normal LA and sinus rhythm, Pollick and Taylor observed at transesophageal echocardiography that the ejection fraction of the LAA was approximately 55%, with average values of maximum anterograde velocity of 0.48 m/s.
In the present study, there was an improvement in the LAA flow velocities with PTMC. The anterograde component of the flow increased from a mean of 19.56 ± 9.48 cm/s to 33.10 ± 14.01 cm/s and the retrograde component of the flow increased from a mean of 24.88 ± 10.66 cm/s to 35.01 ± 16.13 cm/s. These results are similar to a study done by Tatani SB et al. who reported an increase in the anterograde flow velocities from 0.13–0.53 m/s (mean 0.3 m/s) to 0.23–0.51 m/s (mean 0.35/s).
These data suggest the existence of LAA dysfunction in patients with significant mitral stenosis and reflect a compromise of the functional ability of the LAA. Similar data were described by Hwang et al., characterizing a compromise of the intrinsic contractile function of the LAA in mitral stenosis. Such dysfunction of the LAA in mitral stenosis can be explained by the elevation of LA pressure as well as degeneration of the myocardial fibers with a consequent diffuse interstitial fibrosis of LAA resulting from the repeated crisis of the rheumatic activity. Madden has already demonstrated degenerative changes in LAA myocardial fibers and diffused interstitial fibrosis in patients with mitral stenosis.
We also showed improvement in LAA contractile function immediately after PTMC. A study done by Porte et al. also showed early improvement in LAA Doppler flow velocities after balloon mitral valvuloplasty.
The mechanisms underlying the improvement in LAA Doppler outflow after PTMC are as follows:
1. An improvement in the intrinsic LAA function, resulting in an improvement in active LAA contraction
2. Acute reduction in atrial after load induced by PTMC which may passively improve LAA Doppler outflow.
Hoit et al. previously showed that loading conditions can influence LAA flow velocities.
The effect of PTMC on LAA function and on the evolution of SEC in the LA suggests a beneficial effect of the procedure on LA blood stasis and hence reduced incidence of SEC with consequent reduction in the risk of embolism.,,
This study comprised a small group of patients. A larger sample size is required and a follow-up for a longer time after the valvular dilatation procedure to assess the relation of these functional changes in the LAA with a possible reduction in the embolic events.
| Conclusion|| |
This study showed a significance improvement in the LAA velocities and a significant decrease in the LA SEC following PTMC. These changes may lead to a reduction in the risk of systemic embolism. Further studies are needed to validate this hypothesis and to determine whether it would be beneficial to start anticoagulants in patients who are in sinus rhythm but have low LAA flow velocities.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]
[Table 1], [Table 2], [Table 3], [Table 4]