Four Steps (SCORE) for the Repair of Rheumatic Mitral Regurgitation

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This video presents the case of a 23-year-old female, height 158 cm, weight 54 kg, and BMI 21.63, who experienced chest tightness and shortness of breath after activity for more than two months.  
On physical examination, the chest was symmetrical with no deformity. The heart examination revealed a normal apex beat, no thrills, and an enlarged heart border. A grade 3/6 systolic murmur was heard at the mitral area, and the lower limbs showed no edema. Routine blood tests were unremarkable. 

Diagnostic Workup 

The diagnostic workup revealed that the chest X-ray showed a prominent pulmonary artery and a typical rheumatic mitral cardiac silhouette. The ECG showed biphasic P waves in leads V4 to V6. Transthoracic echocardiogram findings included rheumatic mitral valve disease, moderate mitral stenosis with severe regurgitation, moderate tricuspid regurgitation, and mild pulmonary hypertension. The mitral valve area measured 1.5 cm², with a mean gradient of 8 mmHg and a peak gradient of 19 mmHg. The reflux fraction was 78 percent, with an instantaneous regurgitant area of 14.8 cm². Additionally, the left atrium was enlarged, measuring 58 mm.  

Preoperative Transesophageal (TEE) Findings 

The four-chamber view revealed poor coaptation without leaflet prolapse, thickened leaflets and subvalvular structures, and severe central regurgitation. Three-dimensional reconstruction confirmed the classical fish-mouth appearance of the mitral orifice caused by commissural fusion. 

Preoperative Assessment  

The preoperative assessment impression indicated rheumatic heart disease, stage C, moderate mitral stenosis with severe regurgitation, moderate tricuspid regurgitation, mild pulmonary arterial hypertension, New York Heart Association (NYHA) Class II heart function, and a Society of Thoracic Surgeons (STS) risk score of 1.2 percent. 

Surgical Indication Overview 

According to current guidelines, surgical repair for primary mitral regurgitation is indicated in symptomatic patients with severe regurgitation and preserved left ventricular function (Class I, Level of Evidence B). This patient met those criteria (1, 2). 

Surgical Procedure 

A lower hemisternotomy approach was used. The patient underwent rheumatic mitral valve repair with a 34 mm annuloplasty ring, tricuspid valve repair with a 28 mm ring, and left atrial plication. The cardiopulmonary bypass time was 130 minutes, with an aortic cross-clamp time of 78 minutes. The postoperative ICU stay lasted 38 hours, and the total hospital stay was nine days. 

This procedure followed the Shaving, Checking, Opening (Commissurotomy), and Relaxing (SCORE) technique, a systematic method developed for rheumatic mitral repair. SCORE includes four key steps designed to restore mobility and function to the rheumatic mitral valve by addressing both commissural fusion and subvalvular restriction. 

Intraoperative Exploration 

The fused commissures were exposed using two pairs of nerve hooks. Subvalvular lesions included shortened chordae and hypertrophic, fused papillary muscles. No valve calcification was found, indicating that the valve tissue was adequate and pliable, which was favorable for repair. 

The SCORE Procedure on C1 

The following steps demonstrate the Shaving, Checking, and Commissurotomy approach on the anterolateral commissure (C1). The goal is to restore the pliability and opening of the fused C1. To begin, two stay sutures were placed to expose the commissure. By gently approximating the sutures toward the valve closure line, the surgeons were able to assess the degree of thickening and fusion. Shaving of the fused surface was then performed to remove pericommissural fibrosis, effectively revealing the underlying natural contour and insertion of C1. Following this, a precise commissurotomy was carried out to maximize the commissural opening while minimizing the risk of iatrogenic regurgitation. 

Relaxing of the Anterior Papillary Muscles 

The following steps demonstrate the Relaxing phase focused on the anterior papillary muscles beneath C1. After completing the anatomically guided commissurotomy, the fused anterior papillary muscles supporting C1 were fully exposed and assessed. To optimize visualization, fine chordae near the leaflet edges, which provided minimal structural support, were carefully divided. This allowed for a clearer understanding of the fusion pattern within the muscle heads. Subsequently, a precise muscle division was performed to restore the normal subvalvular anatomy and relieve stenosis at the C1 level. 

The SCORE Procedure on C2 

The following steps demonstrate Shaving, Checking, and Commissurotomy on C2. The same surgical principle was applied at C2; however, due to the broader extent of fibrosis and fusion, a slightly more extensive shaving was required. Commissurotomy was initiated at the insertion point of C2 with a stab incision using a No. 11 scalpel blade. It was crucial to keep the cutting edge facing upward to avoid unintentional chordal rupture, which is a key factor contributing to postoperative pericommissural regurgitation. 

Relaxing of the Posterior Papillary Muscles 

The following steps demonstrate Relaxing of the posterior papillary muscles. Similar to the approach used for the C1 papillary muscles, a thorough assessment of the fusion pattern was essential before muscle division. This step aimed to relieve subvalvular stenosis while carefully avoiding injury to the posterior wall of the left ventricle. Preserving essential supporting chordae in situ is also vital to prevent new-onset postoperative regurgitation. In this case, extensive fusion was observed, both in an interchordal pattern and between the left ventricular wall and the subvalvular apparatus beneath C2. 

Fibrous Tissue Stripping 

This video also features a less commonly used technique in rheumatic mitral repair. Given the patient’s young age, fibrous tissue stripping was added to maximize long-term durability and reduce the likelihood of reintervention. The purpose of this step was to restore leaflet pliability and enhance coaptation. While further studies and follow-up are needed to confirm whether this technique improves repair durability, intraoperative inspection confirmed a more normal-looking valve following the procedure. 

Completion of Mitral Repair 

Saline tests conducted before and after ring annuloplasty showed satisfactory repair outcomes, with no residual regurgitation and adequate mitral valve opening. 

Immediate postoperative transesophageal echocardiography (TEE) in the operating room confirmed unrestricted leaflet motion, effective closure and opening, a peak gradient of 3 mmHg, and only trivial residual regurgitation. 

References

1. Circulation. 2021;143:e00–e00. DOI: 10.1161/CIR.0000000000000923
2. Valvular Surgery Group, Society of Thoracic and Cardiovascular Surgery, Chinese Medical Association. Chinese expert consensus on surgical treatment of rheumatic mitral valve disease [J].

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