European Journal of Cardiovascular Medicine

Rheumatic Fever and Rheumatic Heart Disease is a significant cause of cardiovascular diseases in the world today. Although all cardiac valves may be involved by the Rheumatic process, the Mitral Valve is involved most prominently and in virtually all cases. Rheumatic Mitral Stenosis is associated with considerable fusion of the commissures and reduction of mitral valve area and leaflet mobility (1,2).

During acute rheumatic fever with carditis, involvement of the Mitral Valve consists of tiny, translucent nodules located along the line of closure of the valve, occasionally also involving subvalvular parts of the chordae. Microscopic sections of these nodules show largely nonspecific proliferation of fibroblasts and macrophages. These translucent vegetations later become opaque and grey, and eventually more of the valve leaflet becomes thickened.

LAA, a remnant of the embryonic atrium, also has an important pathophysiological function because it is more compliant than the LA and its contractile capacity prevents blood stasis (3,4). Impaired function of the Left Atrial Appendages (LAA), such as reduced flow velocity and reduced atrial strain, typically results in thrombus formation (5). In Mitral Stenosis Left Atrial function may be disrupted because of increased Left Atrial afterload. Recent studies have also shown a beneficial role of the LAA in modulating left atrial pressure (6). Impaired function of the LAA, such as reduced flow velocity, typically results in LA thrombus formation (7), with LAA thrombi more prevalent in presence of low velocities than higher velocities (8).  LAA velocity is an important predictor of thrombus formation, independent of other hemostatic variables, including platelet and thrombotic activity (9).

Studies shown that LAA performance improves within a short time after Percutaneous Transvenous Mitral Commissurotomy (PTMC) in patients with AF or in SR(10,11).Recovery of LAA velocity after PTMC depends directly upon improving the mitral valve hemodynamics and reducing the trans-mitral gradient(10). Since introduction of PTMC in 1984 by Inoue et al, it has become established as a safe and effective treatment for rheumatic MS, with results that are equivalent to surgical valvotomy (11).

We conducted this study with aim to see the impact of PTMC on Left Atrial Appendage functions by assessing the LAA ejection fraction (LAAEF) and LAA emptying velocity (LAAEV) using Transesophageal Echocardiography in MS patients before, after 1 month and 1 year after PTMC.

Prospective observation study conducted in the department of cardiology at LPS institute of Cardiology, between Feb 2020 to March 2022. Patients with severe mitral stenosis with suitable valve morphology who are undergoing PTMC will be selected for this study.

Inclusion criteria - Patients with symptomatic severe rheumatic MS who are undergoing PTMC and having normal sinus rhythm, Normal LV ejection fraction (EF) (≥55%), having right ventricular systolic annular velocity ≥9.5 cm/s before procedure and having suitable valve morphology by echocardiography (Wilkins score ≤ 8) are included in the study. All other (atrial fibrillation, other valve defects etc) were excluded from our study.

All patients were subjected to thorough history taking, full clinical examination, 12 lead ECG, full 2D, M mode & Doppler transthoracic echocardiographic and transoesophageal echocardiography study in standard views. Left Atrial regional function and deformation properties were studied using 2D speckle Strain imaging. All details were plotted in tables and statistically studied. All patients also underwent transesophageal echo prior to BMV to rule our left atrial and left atrial appendages clot. After PTMC, TEE was performed at least after1 month and then at 12 months follow up. Balloon Mitral Valvotomy was considered successful when post procedure echo revealed mitral valve area > 1.5cm2 by echo with less than 2+ Mitral Regurgitation. All findings were recorded, tabulated and analysed after complete follow up.

During the period of 02 year, 50 patients were included in the study of who underwent successful Percutaneous BMV for severe symptomatic rheumatic Mitral Stenosis. Relevant parameter related to study measured prior to study, 24 hr post BMV, 01 month and 01-year post BMV. Among 50 patients included in study 22(44%) were male and 28(56%) were female. Youngest patient was 13-year female and eldest one was 51 years male.

Graph 01- Age and sex wise distribution of patients.

Table 01: LAA Function Before and After BMV

In terms of LAA performance, LAA end diastolic volume (LAAEDV) did not change significantly after PTMC (P = 0. 243), while LAA end systolic volume was decreased significantly after PTMC (P) at 1 month follow up with almost similar values at 12 months follow up. The LAA ejection fraction (LAAEF) increased significantly from pre BMV value of 42.82±1.572 % to 54.24±1.341% (p value<0.001) at 1 month follow up at 12 months follow up it was 54.22±1.411 % which remained significant improvement from pre BMV level. MVA by planimetry increased significantly from pre BMV value of 0.89±0.11 cm2 to 1.83±0.3 cm2 at 24 hr post BMV (P value0.031) while at 1month follow up it was 1.89±0.2 cm2( P value0.011) and at 12 months this improvement was maintained. At end of 12 months follow up there was 107 % increase in mitral valve area. Peak atrial longitudinal stain improved significantly over a period of 12 months. From pre BMV value of 6.5±11.6% to 11.1±9.5 (P value- < 0.001). Immediately 24 hr post BMV there was also a significant improvement in PALS from 6.5±11.6% to7.7±10.5%. Decrease in PASP 24 hr BMV was only 8% which reached to total decrement of 39% at 1 month follow up and to 45 % at 12 months follow up. It implies that effect of BMV on PASP occurs immediately as well as during follow up.

LAA emptying velocity (LAAEV) increment upto 20% seen post BMV at 1 month follow up which remained consistent at 12 months follow up (compared to pre BMV). There was 28 % increment in LAAEF seen post BMV at 1 month follow up which was consistent at 12 months follow up (compared to pre BMV).

In a similar study by Rohani, et al (12) acute effect of BMV and MVR in patients with MS Positive peak LA strain improved from pre BMV value of 5.1±11.6 % to post BMV 6.5±17.7%.  Di Salvo et al (13) had reported atrial peak Systolic Strain as one of the best predictors for maintenance of sinus rhythm in patients with lone AF. In a study by Vieira ML et al (14), Mitral valve area increased to 1.7+0.11 cm2 post- BMV.

In a study by Aslanabadi N, Jafaripour I, et al 2015 (15) 61did a study aimed to investigate the effects of PTMC on left atrial appendage function in patients with sinus Rhythm and Atrial Fibrillation by TEE.  LAA ejection fraction (LAAEF) and the LAA emptying velocity (LAAEV) were improved significantly after PTMC in both groups with SR and AF (P<0.001 for both). In our study, LAA end diastolic volume (LAAEDV) did not change significantly after PTMC while LAA end systolic volume was decreased significantly after PTMC at 1 month follow up with almost similar values at 12 months follow up. LAA emptying velocity (LAAEV) also increased significantly from pre BMV value of 22.10±1.734 cm/sec to 26.72±1.648 cm/sec at 1 month post BMV follow up and at 12 months follow up it was 25.99±1.540 which remained significant improvement from pre BMV level. LAA emptying velocity (LAAEV) increment upto 20% seen post BMV at 1 month follow up which remained consistent at 12 months follow up (compared to pre BMV).

In our study , LAA end diastolic volume (LAAEDV) did not change significantly after PTMC (P = 0. 243), while LAA end systolic volume was decreased significantly after PTMC at 1 month follow up with almost similar values at 12 months follow up. The LAA ejection fraction (LAAEF) increased significantly from pre BMV value of 42.82±1.572 % to 54.24±1.341% at 1 month follow up and at 12 months follow up it was 54.22±1.411 % which remained significant improvement from pre BMV level. There was 28 % increment in LAAEF seen post BMV at 1 month follow up which was consistent at 12 months follow up(compared to pre BMV).

Left atrial appendage functions assessed in terms of LAA ejection fraction and LAA emptying velocity by transesophageal echocardiography at least one month post PTMC have also shown significant improvement. At one year follow up this improvement remained consistent. However, our study population was very less and clinical implications were not directly assessed in our study like improvement in NYHA class. Also, patients with atrial fibrillation which is an important subgroup of patients of mitral stenosis were not included. Thus, further large and detailed studies needed to establish our findings.

Figure 01: Sample of left atrial appendage area measurement

Figure 02: left atrial appendage velocity

Figure 03: Apical four and two chamber six LA segments. LA, left atrial.

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