|Year : 2020 | Volume
| Issue : 3 | Page : 232-236
Impact of Mitral Valve Replacement on the Right Ventricle Function in Mitral Stenosis
N Swaminathan, Venkatesan S Sangareddi, G Ravishankar, Justin Paul, L Alen Binny
Institute of Cardiology, Rajiv Gandhi Government General Hospital, Chennai, Tamil Nadu, India
|Date of Submission||10-Mar-2020|
|Date of Decision||29-Mar-2020|
|Date of Acceptance||07-Apr-2020|
|Date of Web Publication||18-Dec-2020|
Dr. L Alen Binny
Institute of Cardiology, Rajiv Gandhi Government General Hospital, Chennai, Tamil Nadu
Source of Support: None, Conflict of Interest: None
Background: In patients with mitral stenosis (MS), right ventricular (RV) function may be altered due to an increase in the left atrial pressure and/or changes in pulmonary arteriolar vasculature or may be affected by rheumatic process directly. Aims: In this study we have evaluated the recovery of RV function upto 3 months in patients undergoing mitral valve replacement (MVR) using two dimensional and tissue Doppler echocardiographic indices (TDI). Materials and Methods: A total of 30 patients who were advised MVR were enrolled prospectively. All patients underwent MVR successfully. RV function was assessed using conventional and TDI pre-operatively, 1 week, and 3 months after surgery. Results: New York Heart Association (NYHA) functional class improved significantly at the end of one week. Mean transmitral gradient reduced postoperatively. Tricuspid regurgitation severity reduced significantly. Significant RV reverse remodelling was noted at the end of 3 months. Global RV function parameters fractional area change and RV Tei index improved significantly at the end of 3 months. In patients with mild to moderate pulmonary hypertension (PH), global RV function improved significantly, RV remodelling was seen. In patients with severe PH, both global and longitudinal functions did not improve at the end of 3 months follow up, though RV remodelling was noticed. Conclusion: In patients with severe rheumatic MS whenever per-cutaneous trans-mitral commissurotomy is not feasible, MVR promotes RV remodelling and improvement in RV function along with significant improvement in NYHA functional status. But this improvement in RV function was noted only in patients with mild to moderate PH rather than in patients with severe PH.
Keywords: Mitral stenosis, mitral valve replacement, pulmonary hypertension, right ventricle function
|How to cite this article:|
Swaminathan N, Sangareddi VS, Ravishankar G, Paul J, Binny L A. Impact of Mitral Valve Replacement on the Right Ventricle Function in Mitral Stenosis. J Indian Acad Echocardiogr Cardiovasc Imaging 2020;4:232-6
|How to cite this URL:|
Swaminathan N, Sangareddi VS, Ravishankar G, Paul J, Binny L A. Impact of Mitral Valve Replacement on the Right Ventricle Function in Mitral Stenosis. J Indian Acad Echocardiogr Cardiovasc Imaging [serial online] 2020 [cited 2021 Apr 13];4:232-6. Available from: https://www.jiaecho.org/text.asp?2020/4/3/232/303953
| Introduction|| |
Rheumatic heart disease (RHD) is an important health problem in developing countries. Mitral stenosis (MS) is the most common presentation of RHD in developing countries. From available data from RHD studies, the estimated average prevalence is 0.5/1000 children in the age group of 5–15 years. There are expected to be more than 3.6 million patients of RHD estimated from 2011 census. Almost 44,000 patients are added every year, and expected mortality is 1.5%–3.3% per year. The timing of intervention in valvular heart disease is decided by the clinical, morphological, and functional characteristics. Although percutaneous transluminal mitral commissurotomy (PTMC) has become an effective and safe treatment for MS patients, surgical mitral valve replacement (MVR) has its role in patients in whom PTMC is not possible due to the morphology of the valve. The right ventricular (RV) function is an important factor which determines the recovery of the patient postoperatively and the long-term improvement in functional status. In patients with MS, RV function may be altered by increased left atrial pressure, changes in pulmonary vasculature, or by rheumatic process itself. Many studies have evaluated the changes in RV function postcardiac surgery and its impact in overall outcome.,
The purpose of this study was to analyze the recovery of RV function after MVR in isolated MS patients in immediate and short term (3 months) follow-up using two-dimensional echocardiographic and tissue Doppler indices.
| Materials and Methods|| |
The study was done in a Rajiv Gandhi Government General Hospital Chennai from June 2018 to June 2019. A total of thirty patients in all age groups with isolated MS in whom PTMC was not feasible and were advised surgical MVR were enrolled in the study. RV function was assessed using conventional two-dimensional and Tissue Doppler imaging (TDI) before surgery, 1 week and 3 months after surgery. New York Heart Association (NYHA) Functional class, tricuspid annular plane systolic excursion (TAPSE), RV systolic velocity (RVSm), RV myocardial performance (RIMP), fractional area change (FAC), pulmonary artery systolic pressure (PASP), RV basal diameter (systole and diastole). All studies were obtained using Aloka ultrasonographic machine equipped with 3.5 MHz transducer.
- All age group
- Both male and female
- Severe MS (those were not suitable for PTMC)
- Normal left ventricular (LV) function.
- More than mild mitral regurgitation
- Other causes of pulmonary hypertension (PH)
- Associated aortic valve lesion
- LV dysfunction.
The mitral valve area was measured by planimetry. Transmitral gradients were measured using Bernoulli's principle from continuous-wave Doppler recordings through mitral inflow. Suitability for PTMC was assessed using Wilkins score and commissural calcium score. Systolic pulmonary artery pressures (PASP) were derived from tricuspid regurgitant jet velocity. The right atrial pressure was calculated by estimating the inferior vena caval size and its variation with respiration. Parameters for RV function were measured according to the American Society of Echocardiography guidelines. TAPSE was measured by displacement of the lateral tricuspid annulus during systole using M mode. RV end-diastolic and end-systolic areas were measured from the RV focused apical four-chamber view to calculate RV FAC. RIMP was calculated as the time between tricuspid valve closure to tricuspid valve opening, divided by the RV ejection time, determined by TDI.
Statistical analysis was performed with Statistical Package for the Social Sciences IBM company, NY, USA. Data were presented as mean ± standard deviation for continuous variables. Comparisons of data before and after MVR were performed using Student's t-test. A P < 0.05 was considered to indicate statistical significance.
| Results|| |
MVR was done through the left atrial approach on pump. St. Jude bileaflet mechanical valve was used in most of the patients (25 patients), and TTK Chitra single leaflet valve was used in the remaining (% patients). The selection of the valve was based on surgeons' preference. The postoperative period was uneventful in all the patients. The postoperative mitral inflow gradients were peak 8.9 ± 2.7 mm Hg, mean 3.5 ± 1.5 mmHg.
A total of 30 patients with severe MS were included prospectively in this study. Twelve patients were <40 years, 11 patients were 40–50 years age, and 7 patients were >50 years 17 patients were female [Figure 1].
Eleven patients had RV dysfunction. Twelve patients had severe PH [Figure 2].
|Figure 2: Preoperative right ventricular (RV) dysfunction and pulmonary hypertension (PHT) severity|
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Most of the patients were in NYHA Functional Class III preoperatively and improved to functional Class I at the end of 1-week post-MVR PASP reduced from 56.4 ± 22.4 to 27.2 ± 6.5 at the end of 3 months [Figure 3]. TAPSE reduced from a preoperative value of 16.0 ± 5.3 to 8.85 ± 2.5 at the end of 1-week post-MVR and improved to 15.1 ± 2.3 at the end of 3 months with no significant change from preoperative value. RVSm also reduced from its preoperative value 10.8 ± 3.39 to 7.55 ± 1.53 at the end of 1 week and improved to 10.15 ± 1.50 at the end of 3 months with no significant change from preoperative value. FAC reduced from 42.1 ± 11.8 to 35.2 ± 7.71 at the end of 1 week but increased significantly to 49.2 ± 7.66 comparing preoperative value. RIMP improved from 0.549 ± 0.152 to 0.44 ± 0.082 at the end of 3 months. Pulmonary acceleration time increased from 73.4 ± 17.9 to 102.3 ± 15.49 at the end of 3 months. RV basal diameter in systole and diastole reduced significantly at the end of 3 months.
|Figure 3: NYHA functional class improvement. NYHA FC: New York Heart Association functional classification, MVR: Mitral valve replacement|
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In patients with severe PH (tricuspid regurgitation peak gradient [TR PG] >60 mmHg), though PASP reduced significantly, among TAPSE, RVSm, FAC, RIMP, none of them showed improvement at the end of 3 months' follow-up. RV basal diameter in systole and diastole reduced significantly from preoperative values.
In patients with mild-to-moderate PH (TR PG <60 mmHg), TAPSE and RVSm did not improve at the end of 3 months, while FAC (from 42.7 ± 11.5 to 50.83 ± 7.84) and RIMP (from 0.55 ± 0.17 to 0.42 ± 0.05) improved significantly at the end of 3 months' follow-up [Figure 4]. RV basal diameters in systole and diastole also reduced significantly.
In patients with preoperative RV dysfunction also, RV function improved at the end of 3 months postsurgery, noticed by improvement in TAPSE from 10.2 ± 3.4 to 13.1 ± 1.60, FAC from 31.7 ± 12.3 to 48.8 ± 9.45, RVSm from 7.4 ± 2.06 to 9 ± 0.89, RIMP from 0.63 ± 0.12 to 0.45 ± 0.10. RV basal diameter in systole and diastole also reduced significantly.
| Discussion|| |
In patients with severe MS, RV function is inherently related to functional capacity, perioperative mortality, and postoperative outcome. Due to asymmetrical shape and narrow acoustic window, the evaluation of RV function is difficult by transthoracic echocardiography. Although a wide variety of techniques have been proposed, none of the echo parameters are considered gold standard at present. In this study, we used various two dimensional and TDI indices to assess RV function in severe MS pre- and post-surgery and a 3 months' follow-up.
NYHA functional class improved at the end of 1 week. PASP reduced significantly, and pulmonary acceleration time improved at the end of 3 months. Significant RV reverse remodeling was noted at the end of 3 months in all the groups. Longitudinal function assessed by TAPSE decreased at the end of 1-week postsurgery but improved to preoperative values with no significant change at the end of 3 months' follow-up. RVSm also reduced from its preoperative value at the end of 1 week and improved at the end of 3 months with no significant change from preoperative value [Table 1]. Several hypotheses have been proposed to explain the fall in longitudinal function in the RV in the immediate postoperative period. Some of them are intraoperative ischemia, right atrial injury due to cannulation, poor myocardial protection, pericardial disruption, postoperative adherence of the right ventricle to thoracic wall and due to geometrical changes in RV chamber in association with paradoxical septal motion. Drighil et al. found that RVSm did not change immediately after PTMC. Global RV function parameters FAC and RIMP improved significantly at the end of 3 months [Table 1]. The improvement is probably due to fall in RV afterload and improvement in contractility. Drighil et al. noticed a significant improvement in RIMP from 0.5 ± 0.2 to 0.3 ± 0.2 (P < 0.0001) and Bensaid et al. observed a nonsignificant improvement in RIMP after PTMC from 0.33 ± 0.1 to 0.36 ± 0.12 (P = 0.2).
|Table 1: Comparision of transthoracic echocardiographic parameters before and after mitral valve replacement|
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In subgroup analysis, in patients with mild-to-moderate PH [Table 2], global RV function improved significantly, RV remodeling was seen, while longitudinal function stayed at preoperative values. In patients with severe PH [Table 3], both global and longitudinal functions did not improve at the end of 3 months' follow-up, though RV remodeling was noticed in this group. Even in patients with preoperative RV dysfunction [Table 4], global and longitudinal RV function improved significantly along with fall in PASP and RV remodeling.
|Table 2: Comparision of pre-and post-mitral valve replacement echo parameters in patients with mild to moderate pulmonary hypertension|
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|Table 3: Comparision of pre-and post-mitral valve replacement echo parameters in patients with severe pulmonary hypertension|
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|Table 4: Comparision of pre-and post-mitral valve replacement echo parameters in patients with right ventricular dysfunction|
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A study by Kumar et al. showed that immediately after PTMC both longitudinal and global functions of the RV improved significantly. However, in our study group, immediately following the surgery (MVR), RV functions actually reduced but improved significantly at the end of 3 month's follow-up.
| Conclusion|| |
In patients with severe rheumatic MS whenever PTMC is not feasible, MVR promotes RV remodeling and improvement in RV function along with significant improvement in NYHA functional status. However, this improvement in RV function was noted only in patients with mild-to-moderate PH rather than in patients with severe PH. Hence, MS should be intervened at an earlier stage before the development of severe PH.
The recovery of RV function was not analyzed in correlation to the indexed mitral valve orifice area. Patients with atrial fibrillation were included. Hence, the impact of atrial fibrillation per se on RV function has its own implications apart from the severity of MS. A longer follow-up of 6 months would have clarified whether the longer duration is required for RV function to recover in case of severe PH.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3], [Table 4]