Rheumatic mitral valve repair in the developing world: ‘a very different ball game’

A recent review article by Chatterjee et al. [1] beautifully illustrated the superiority of mitral valve repair over mitral valve replacement in the pediatric and adolescent population. However, repairing the mitral valve in rheumatics is like ‘putting a hand in fire’. Unlike degenerative mitral valve disease, rheumatic valves are complicated by various degrees of fibrosis, calcification, subvalvular apparatus shortening, and tissue loss, making them a ‘less frequent’ choice for repair. The authors correctly conclude that valve repair should be the goal especially when facilities for monitoring anticoagulation and prosthetic valve function are not available.

While performing the repair in a child, there is only one thing worse than a valve replacement—a suboptimal valve repair. Lack of objective criteria to predict feasibility, longevity, and prognosis of the mitral valve repair in the rheumatic population makes these repairs more dependent on the skill, experience, and 3-dimensional visualization of the surgeon. This is where our scoring system (‘CLAS’ score) for repairing mitral valve in rheumatics to predict feasibility, longevity, and prognosis of the repair comes in handy [2]. The ‘CLAS’ score, as the name suggests, involves four integral sub-units, namely C, Commissures; L, Leaflet; A, Annulus; and S, Sub valvular apparatus (papillary muscles and chordae). Each component of the ‘CLAS’ score is scored individually with a maximum score of 4 (severe disease) and a minimum score of 1 (mild disease). The summation score of the subunits gives the final score. Based on the scores, three complexity groups have been defined: simple repair (complexity score ≤ 8), challenging repair (complexity score 9–12), and high failure expected (complexity score of 13–16). The ‘CLAS’ score is an objective tool to standardize and predict mitral valve repairability. This score successfully unifies the nomenclature across the spectrum of mitral valve disease from rheumatic to degenerative and stenosis to regurgitation.

It is a known fact that intensive preoperative evaluation of valve etiology and pathology is an important key to maximizing repair rates of mitral valve disease [1, 3]. Preoperative echocardiographic ‘CLAS’ score helps in the identification of patients, who have a high likelihood of a complex repair. These patients should be referred to high-volume mitral valve repair centers for successful outcomes.

The experience of the surgeon performing the valve repair also greatly influences the outcome of the repair, possibly due to the lack of objective criteria to predict the complexity and prognosis of the repair. The ‘CLAS’ score helps in reducing the learning curve by helping with appropriate patient selection commensurate with the experience of the surgeon. By systematically breaking down the valve into 3 levels, it makes multi-lesional mitral valve repair a possibility. It also makes the description of the valve pathology and complexity more objective and universal.

As rightly mentioned by Chatterjee et al., choosing a proper ring size is also important in children as the small-sized rings are potentially stenotic in a growing child [1]. As mentioned in our previous publication, augmentation of mitral leaflets using autologous fixed pericardium allowed us to have a successful repair rate of over 90% in rheumatics [4]. This augmentation technique, by allowing a higher coaptation surface, allows bigger annuloplasty rings which enable the valves to be gradient-free even when the children grow up and have a higher cardiac output flowing through their valves. We preferred to augment anterior mitral leaflet (AML) over posterior mitral leaflet (PML) because PML is a relatively passive leaflet, involved more in allowing a gradient-free inflow to the left ventricular than reducing regurgitation. We have seen that PML augmentation in stenotic lesions leads to somewhat higher gradients during follow-up.

Another important issue in this subset is the presence of active carditis which as mentioned in this article is a risk factor for reoperation. This is especially important in the Indian context, given that not all rheumatics are alike (mean age of patients undergoing rheumatic mitral valve repair in most countries is 15–20 years higher than in the Indian subcontinent). Most studies have described mitral repairs on ‘burnt out’ rheumatics rather than active rheumatics (ongoing carditis and/or high likelihood of recurrence given their younger age). We observed this in our series of 106 young children with mitral valve disease [5]. Our series had a sizable proportion of patients (n = 30; 29.6%) in acute and subacute phases of the disease. We were able to demonstrate that intractable heart failure in the presence of acute rheumatic carditis does not preclude a successful repair; however, a highly proactive medical and surgical approach is needed to prevent recurrences of carditis and progression of valvular pathology.

Declarations

Ethical approval

As per our Institutional protocol, for letter to editor ethical approval is not required.

Informed consent

This study was analyzing previously published data and no new patient data was reported; as a result, patient consent was deemed waived.

Conflict of interest

The authors declare no competing interests.