RING+STRING: Successful repair technique for ischemic mitral regurgitation with severe leaflet tethering

Area of Science:

• Cardiovascular Surgery
• Cardiac Surgery
• Heart Valve Repair

Background:

• Ischemic mitral regurgitation (IMR) often presents with residual/recurrent mitral regurgitation (MR) in up to 30% of patients post-ring annuloplasty (RING).
• Standard RING primarily addresses annular dilatation but fails to correct severe leaflet tethering caused by displaced papillary muscles (PM).

Purpose of the Study:

• To evaluate the efficacy of an adjunctive transventricular suture technique (STRING) for papillary muscle repositioning in patients with IMR and severe leaflet tethering undergoing RING.

Main Methods:

• A novel STRING technique was employed, involving transesophageal echocardiography (TEE) guidance for PM repositioning in the loaded beating heart.
• A Teflon-pledgeted suture was anchored in the posterior PM via aortotomy and tied under TEE guidance.
• This was combined with partial ring annuloplasty (median 29 mm) in 30 high-risk patients (tenting height ≥10 mm).

Main Results:

• The combined RING+STRING technique significantly reduced tenting height (14±2 mm to 6±1 mm) and tenting area (3.9±0.9 cm² to 1.0±0.2 cm²).
• A significant decrease in the distance between the posterior papillary muscle and the aorto-mitral continuity was observed (44±4 mm to 37±3 mm).
• Two-year survival was comparable to historical controls (89% vs. 73%), but freedom from MR>II was significantly higher (94% vs. 71%).
• The RING+STRING group showed significant reverse remodeling with decreased end-diastolic and end-systolic ventricular diameters, unlike the control group.
• Only 1 patient in the study group required reoperation for degenerative MR, compared to 2 control patients for recurrent functional MR.

Conclusions:

• The novel STRING technique, when combined with RING, effectively attenuates the high risk of repair failure in IMR patients with severe leaflet tethering.
• This approach leads to significant reverse remodeling and improved long-term outcomes, offering a promising solution for complex IMR cases.