Heart India

REVIEW ARTICLE
Year
: 2020  |  Volume : 8  |  Issue : 3  |  Page : 121--126

Mitral valve assessment and scoring before balloon mitral valvuloplasty


Satyam Rajvanshi1, Ranjit Kumar Nath2, Rajeev Bharadwaj2,  
1 Rajvansh Heart and Vascular Centre, Muzaffarnagar, Uttar Pradesh, India
2 Department of Cardiology, ABVIMS and Dr. RML Hospital, New Delhi, India

Correspondence Address:
Dr. Rajeev Bharadwaj
Department of Cardiology, ABVIMS and Dr. RML Hospital, New Delhi - 110 001
India

Abstract

Management of symptomatic rheumatic mitral stenosis (MS) by nonsurgical techniques has been the therapeutic modality of choice in low- and middle-income countries such as India. In comparison to surgical interventions, catheter-based balloon dilatation has been preferred in cases of rheumatic MS. Various scoring systems, including three-dimensional (3D), 2D transthoracic, and transesophageal echo and fluoroscopy, have been summarized in this review for the evaluation of the morphology of the valve apparatus, including calcification, and subvalvular involvement for predicting favorable outcomes.



How to cite this article:
Rajvanshi S, Nath RK, Bharadwaj R. Mitral valve assessment and scoring before balloon mitral valvuloplasty.Heart India 2020;8:121-126


How to cite this URL:
Rajvanshi S, Nath RK, Bharadwaj R. Mitral valve assessment and scoring before balloon mitral valvuloplasty. Heart India [serial online] 2020 [cited 2021 Jan 26 ];8:121-126
Available from: https://www.heartindia.net/text.asp?2020/8/3/121/301592


Full Text



 Introduction



Rheumatic heart disease causing damage to the cardiac valves is a common disease occurring in the third-world countries including India. Although majority of the advanced valvular heart disease requires surgical intervention to give relief to their symptoms, rheumatic mitral valve (MV) stenosis was initially evaluated for percutaneous valvuloplasty in the early 80's and was found to be successful. However, their success is dependent upon different clinical and morphologic characteristics of the MV and if not selected properly by prior evaluation, the procedure can be counterproductive leading to serious life-threatening complications. Hence, evaluation of the valve morphology and other characteristics has been extensively studied, and today balloon mitral valvuloplasty (BMV) is a standard procedure for treating symptomatic rheumatic MV stenosis if the preprocedure morphology of the valve and other clinical characteristics are suitable.

 History



Surgical commisurotomy was proposed as a treatment for mitral stenosis (MS) in the first decade of the 20th century. First successful closed mitral commisurotomy was performed in 1923 by Elliot cutler.[1] The technique was established by 1940s. Open mitral commisurotomy (OMC) and replacement of MV became surgical procedures of choice after cardiopulmonary bypass was developed in 1960s.

Kanji Inuoe, Japanese cardiovascular surgeon, designed a balloon catheter system in 1976.[2] Initially, it was tried as a means to separate fused commissars of MV during OMC. The system was redesigned in 1980. The first human clinical application of BMV percutaneously was successful in 1982 and initial reports of six patients was published in 1984.[2] Subsequently, the reports of polyethylene cylindrical balloons, double balloons being used for this purpose were published by Lock et al.[3] and Al Zaibag et al.[4] Palacios et al. published the first report of successful use in calcific MS.[5]

The surgeons chose the patients for commisurotomy versus valve replacement on the basis of valve structure and pathology. Because percutaneous balloon dilation was considered experimental, patients who were poor candidates for surgical valve replacement were those initially chosen for it – elderly, severely deformed valve, and heavy valvular calcification.[6] For the cardiologists, which valves might respond favorably to percutaneous balloon dilation was still an unanswered question.

 Procedural Characteristics and Result



From 1988 to 1990, various research papers were published analyzing the factors affecting the immediate and long-term outcomes of percutaneous balloon dilation.[7],[8],[9],[10],[11] Various factors which were analysed in relation to outcome included clinical factors such as age, sex, NYHA class, baseline rhythm, echocardiographic, and hemodynamic factors such as MV structure, MV area (MVA), left atrial (LA) size, mitral regurgitation (MR) grade, cardiac output, transmitral gradient, pulmonary vascular resistance, left ventricular (LV) end diastolic pressure, and technical factors such as type of balloon, effective balloon dilatation area, number of inflations, and presence of fluoroscopic calcium.

The “Suboptimal” outcome post-BMV has been earlier defined [7] as the presence of any one of the following: (a) a final valve area <1.0 cm 2, (b) a post-dilatation mean LA pressure >10 mmHg, or (c) a change in area <25% of the initial valve area in those with a MVA >1.0 cm 2 before the procedure, (d) presence of more than moderate MR. More recent papers define “optimal” result as final MVA 1.50 cm 2 or greater (or increase in MVA by at least 50%) without increase in severity of MR by more than 1 grade.[12]

The strongest predictor of immediate outcome of balloon dilation was MV structure.[11] An echocardiographic scoring system was introduced by Wilkins et al. to score valve structures [Table 1].[7] This score included four variables – leaflet mobility, leaflet thickening, calcification, and subvalvular thickening. Each variable was given a score from 1 to 4, and total score was given for a valve out of 16. Most patients with a total echocardiographic score of more than 11 had a suboptimal result. Most patients with a score of <9 had an optimal result. The score failed to predict the outcome in those with scores of 9–11. The sensitivity and specificity to predict an optimal outcome were maximal at score of 8.[7],[11]{Table 1}

Wilkins' score has various shortcomings.[13] Echocardiography in general is limited in ability to differentiate nodular fibrosis from calcification. Wilkins' score does not assess commissural calcification. It does not account for the uneven distribution of pathological abnormalities, and relative contribution of each variable, thus underestimates subvalvular disease. In general, more the number of variables assessed, more is the inter- and intra-observer variability in assessing scores.

Reid et al. proposed another MV morphological scoring system by including commissural calcium scoring along with leaflet motion, thickness, and subvalvular disease.[14] They concluded that leaflet mobility was the only independent morphological feature predicting change in MVA post-BMV. The presence of commissural calcium, Pre-BMV MVA, and LA size (correlates with duration of disease) also predicted BMV outcome in multivariate analysis. Total morphological score showed a weaker relationship with outcome.

French 3-group grading by Lung and Cormier is another scoring system giving greater importance to subvalvular pathology and presence of fluoroscopic calcium [Table 2].[15] Fluoroscopy was used to classify patients with calcified valves as limited ability of echocardiography to differentiate nodular fibrosis from calcification. Higher group, smaller MVA (<1 cm 2), higher Age (>50 yrs), and history of previous commisurotomy were the main predictors of suboptimal outcome.{Table 2}

Severe MR remains as one of the most important complications of this technique, with an incidence between 1.4% and 19%.[16],[17] This complication confers an adverse prognosis and frequently requires intensive treatment and urgent MV surgery. MR Echocardiographic score was developed by Padial et al. to predict the development of significant MR after BMV [Table 3].[18] Padial et al. emphasized that uneven valvular thickening and presence of thin segments in thickened valves is major cause for the development of severe MR post BMV. The cut-off value of 10 in Padial MR score gave 90% sensitivity and 97% specificity to predict the development of severe MR post-BMV.{Table 3}

The total score is the sum of these echocardiographic features (maximum 16).

Many reports have stressed the importance of commissural morphology as shown in [Figure 1] in determining the outcome of BMV [18],[19],[20],[21],[22],[23],[24] and demonstrated commissural splitting as the pivotal mechanism by which MVA is increased during the procedure.[12],[19] Commissural calcification also predicts the occurrence of substantial MR post BMV.[18],[25] This complication occurs if resistance to commissural splitting, offered by calcification in one or both commissars, leads to leaflet tear.[25] Transthoracic echocardiography (TTE) grading of commissural calcification 0-4 using parasternal short-axis views has been shown to be a significant predictor of optimal BMV outcome with poor outcome if score is 3 or more [Table 4] and [Table 5]. Some reports have found its influence greatest in patients with a Wilkins echo score <8. Calcification of one commissure or more predicts a <50% probability of achieving a valve area above 1.50 cm 2.[22]{Figure 1}{Table 4}{Table 5}

Transesophageal echocardiography (TEE) assessment of commissural morphology and calcification is a significant predictor of BMV outcome.[26],[27] Commissural assessment by TEE in comparison with TTE offers superior resolution of the MV apparatus and overcomes problems caused by anterior leaflet shadowing, thereby allowing more accurate localization of mitral calcification. A novel TEE method for systematic scanning of the whole length of the mitral commissars has been proposed.[26] A commissural score from 0 to 4 has been proposed. Higher score predicted better BMV outcome. TEE score was more accurate in predicting poor outcome in patients with Wilkins score 8 or less.[26],[27]

[Table 6] Rifaie et al.[28] proposed novel echocardiographic score which composed of only two variables: leaflet/commissural calcification and subvalvular disease as shown in [Figure 2]. PTMC was done by standard double-balloon technique. This score was easier to use and cutoff value of total score 4 or more (out of 12) had better specificity (82.9% vs. 74.3%) and sensitivity (86% vs. 60%) compared to Wilkins' score for the prediction of suboptimal outcome and severe MR following BMV.{Table 6}{Figure 2}

Nunes et al.[12] proposed yet another novel grading involving four predictors: Presence of MVA <1 cm 2, quantitative assessment of commissural morphology (Commissural Area ratio >1.25), limited valve mobility (Maximal leaflet mobility 12 mm or less), and severe subvalvular disease [Table 7]. Higher scores were shown to be more accurate than Wilkins score in predicting suboptimal outcome post BMV.{Table 7}

Real time three-dimensional echocardiography (RT3DE) provides more detailed morphologic analysis of MV apparatus including calcification and subvalvular involvement [Table 8].[29],[30] Three-dimensional (3D) echo, though more informative, is more time-consuming and complex, compared to conventional 2D echo. 3D Echo variables complement 2D echo in MV pre-BMV assessment. Anwar et al. proposed a 3D echo score to predict BMV outcome more accurately.[29] Individual RT3DE score points of leaflets and subvalvular apparatus summed to calculate the total score, ranging from 0 to 31 points. Total score of mild MV involvement was defined as <8 points, moderate MV involvement 8–13, and severe MV involvement >14. Higher scores correlated with poor BMV outcome.{Table 8}

 Conclusions



Meticulous evaluation of the MV with all available evaluation tools is the key for selecting proper patient to undergo BMV. Chest X-ray may help in detecting any abnormality of thoracic cage, making septal puncture difficult or challenging. TTE is the cornerstone of morphological evaluation of the valve leaflets, but if possible TEE will give added advantage in this process. Furthermore, TEE easily rules out any hidden thrombi in the LA appendage, especially in the elderly and with atrial fibrillation. Preprocedure plain fluoroscopy in the catheterization table before starting the procedure may pick-up rare patient with significant calcification that was missed by other evaluation modalities. If we use all these assessment and scoring modalities, more successful procedure can be expected minimizing complications.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

Authors' Contributions

Dr Satyam Rajvanshi: concept and design. Dr Ranjit k. Nath: expert on the subject and critical review of the article. Dr Rajeev Bharadwaj(corresponding author): drafting and design of the article and critical interpretation of the literature associated with the subject.

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