Mitral valve repair

Mitral valve repair or mitral valvuloplasty is a surgical method for treatment of a deficient mitral valve, which comprises removal of redundant valvular tissue and fixation of ruptured/elongated chordae tendineae rather than the whole replacement of the valve.

History and etymology

The first successful mitral valvuloplasty was performed by Elliott Cutler at the Peter Bent Brigham Hospital on a 12-year-old girl with rheumatic valve disease and stenosis in 1923 with a transventricular approach ¹. The first mitral commissurotomy was performed by the Englishman Henry Souttar in 1925 with a finger-guided transatrial approach. In 1948 the first large series of closed mitral valvuloplasties was performed by Dwight Harken at Brigham’s and Women’s Hospital mainly in patients with rheumatic valve disease.

The cardiopulmonary bypass was developed in the 1950s with further changes in the technique and the introduction of mitral valve replacement. The concept for the surgical techniques of mitral valve repair which have become standard treatment nowadays has been coined by the French cardiac surgeon Alain F. Carpentier and later Gerald Lawrie ^1,2.

Indications

Mitral valve repair is indicated for severe mitral valve dysfunction in the following situations and is generally preferred over mitral valve replacement if a successful and durable repair is expected ^1-5:

• degenerative mitral valve disease (most common 60-70%)
• rheumatic mitral valve disease
• infective endocarditis (congestive heart failure, abscess formation, refractory sepsis, systemic embolism)
• selected cases with ischemic heart disease

Recommendations according to the AHA/ACC 2020 and or ESC/EACTS 2017 guidelines:

• acute severe mitral regurgitation and a high likelihood of durable repair
• chronic severe primary mitral regurgitation
  • symptomatic patients
  • asymptomatic patients with left ventricular dysfunction (LVEF ≤60%)
  • asymptomatic and preserved left ventricular function and a high likelihood of durable repair
    • and low expected mortality rate
    • new-onset atrial fibrillation or pulmonary hypertension (PAP > 50mmHg)
    • progressive increase in left ventricular size
• ​secondary mitral regurgitation with cardiac surgery for other indications (e.g. CABG)
• severe rheumatic mitral stenosis (in situations where percutaneous mitral commissurotomy is contraindicated or unavailable)

Contraindications

Considered contraindications of mitral valve repair include ^1,6,7:

• asymptomatic patients with preserved left ventricular function with significant doubt of feasibility
• isolated mitral valve surgery for mild mitral regurgitation
• situations where a successful and durable repair is not expected e.g.:
  • severe leaflet calcification
  • annular dilatation with severe leaflet tethering and abundant tenting (e.g. ≥10 mm)
  • inferolateral basal left ventricular aneurysm
  • severe leaflet destruction
  • complete papillary muscle rupture with cardiogenic shock

Procedure

The procedure and technique of mitral valve repair also depend on the indication. A rough overview of the surgical procedure includes the following steps ^1,2:

• sternotomy, lower partial sternotomy, right thoracotomy, endoscopic and robotic approaches
• cardiopulmonary bypass set up
• intraoperative assessment of the mitral valve
• leaflet repair: quadrangular or limited triangular resection, commissurotomy, commissuroplasty etc.
• cord repair: leaflet suspension with artificial cords, chordal or papillary muscle shortening etc.               
• annuloplasty ring placement, annular plication, sliding leaflet annuloplasty etc.
• assessment of valve competence

Complications

Complications of mitral valve repair include the following ^1,2:

• perioperative complications (e.g. cardiac tamponade)
• mechanical failure
• structural valve degeneration
• recurrent mitral regurgitation
• recurrent mitral stenosis
• valve thrombosis and thromboembolic events
• anticoagulant-related hemorrhage
• infective endocarditis
• paravalvular leak

Radiographic features

Echocardiography

Echocardiography is considered is usually the first-line imaging modality for the evaluation of mitral valvular disorders and follow-up of mitral valve repair. It can identify mitral valve thickening, assess leaflet coaptation, recurrent mitral insufficiency or stenosis or mitral regurgitation as well as paravalvular leak or abscesses.

CT

Due to good spatial resolution, cardiac CT can assess the thickness of the mitral leaflets assess mitral leaflet and mitral annular calcification and aid in periprocedural planning as well as in the detection of complications such as paravalvular leak and abscesses.

MRI

Cardiac MRI can assess cardiac volumes and cardiac function. Furthermore, it can aid in the assessment of mitral regurgitation, if there are discrepancies between echocardiography and clinical findings.

Radiology report

The radiological report should include a description of the following features:

• mitral valve competence
  • mitral valve prolapse
  • mitral insufficiency
  • mitral stenosis
  • mitral annulus disjunction
• left ventricular volumes and measurements
• wall motion abnormalities
• myocardial scar tissue

Outcomes

Mitral valve repair has improved preservation of left ventricular function, less thromboembolic events and better survival in the setting of mitral regurgitation in comparison to mitral valve replacement ⁵. Perioperative mortality has been reported to be clearly <1% for rheumatic and myxomatous valve disease and in the range of 4-5% for functional and ischemic disease ^1,5. Long term survival is also subject to the underlying cause with best results in myxomatous mitral valve disease followed by rheumatic valvular disease and significantly worse outcomes in ischemic functional disease ⁵.

Advantages

Advantages of mitral valve repair over mitral valve replacement include ⁵:

• low operative mortality
• preserved left ventricular function
• less replacement-related complications as thromboembolism, anticoagulant-related hemorrhage or
• infective endocarditis
• equal or superior durability in most degenerative mitral valve disease
• acceptable in complex valvular pathology

Disadvantages

Disadvantages of mitral valve repair over mitral valve replacement are ⁵:

• no benefit in very complex degenerative valve disease
• no benefit in ischemic heart disease with moderate to severe mitral regurgitation
• slightly decreased durability in rheumatic valve disease