Transcatheter Valvuloplasty

LEARNING OBJECTIVES

• 1.

  Patient selection based on anatomical features for percutaneous mitral commissurotomy.

• 2.

  Procedural steps of percutaneous mitral commissurotomy.

• 3.

  To identify complications of percutaneous mitral commissurotomy and management.

• 4.

  Long-term results of percutaneous mitral commissurotomy

Kollaborate link: https://www.kollaborate.tv/link?id=614b9325b57d4.

INTRODUCTION

Mitral stenosis (MS) continues to be the most common valvular heart disease in the developing and underdeveloped nations. Globally the most common cause of MS is rheumatic heart disease and the prevalence of rheumatic heart disease ranges between 0.6% and 14% across Asia and Africa. ^, The other causes of MS include mitral annular calcification, and rarely congenital MS or infiltrative conditions. Percutaneous mitral commissurotomy (PMC) was first described in 1984 by Inoue and his colleagues. This first case series consisted of five patients that had marked reduction in transmitral gradients along with improvement in clinical status. Before the advent of PMC, closed surgical commissurotomy was the only treatment option available for MS. Over the last 36 years, a large number of patients have been treated with this procedure.

PATIENT SELECTION

After holistic evaluation of the patient (that includes the history, quality of life, functional status and physical examination), transthoracic echocardiography (TTE) is the key next step in evaluating eligibility for PMC suitability. TTE evaluates the mitral valve area, transmitral gradient, pulmonary pressure, and the right ventricular function. PMC is considered for patients with a mitral valve area of less 1.5 cm ² . Other aspects that need to be taken into account include clinical status, transmitral gradient and body mass index. In addition to mitral valve area and gradient, TTE also assesses leaflet thickening/calcification/pliability, commissural fusion, subvalvular pathology especially calcification. PMC is not suited for patients with severe subvalvular pathology and minimal commissural fusion. Fig. 23.1 is pathological specimen demonstrating rheumatic MS. Mitral valve morphology based on TTE have been well described and the most important contemporary scores are Wilkins/Cormier score. Wilkins score of 8 or lower or a Cormier class 1 is considered suitable for PMC. The scoring systems are limited by a lack of reproducibility and often underestimate subvalvular pathology. Off-axis parasternal views to visualize papillary muscles and chordal structure can be very useful ( Table 23.1 ).

TABLE 23.1

Scoring Systems Based on Echocardiography for Mitral Valve Intervention

Wilkins or Abascal Score
Grade	SCORED MITRAL VALVE CHARACTERISTICS
	Leaflet Mobility	Leaflet Thickening	Leaflet Calcification	Involvement of Subvalvular Apparatus
1	Highly mobile with only leaflet tips restricted	Leaflet near normal in thickness (45 mm)	Single area of increased echo brightness	Minimal thickening just below the MV leaflets
2	Leaflet mid and base portions have normal mobility	Midleaflets normal, considerable thickening of leaflet margins (58 mm)	Scattered areas of brightness confined to leaflet margins	Thickening of chordal structures extending to one-third of the chordal length
3	Valve continues to move forward in diastole, mainly from the base	Thickening extending through the entire leaflets (5 8 mm)	Brightness extending into midportions of the leaflets	Thickening extended to distal third of the chords
4	No or minimal forward movement of the leaflets in diastole	Considerable thickening of all leaflet tissue (>810 mm)	Extensive brightness throughout much of the tissue leaflet	Extensive thickening and shortening of all chordal structures extending down to the papillary muscle
Interpretation of result	Score range: 4–16. A score >8 suggests the MV may not be suitable to PMBC and is associated with poor short- and long-term results.
Group assignment according to anatomical characteristics of the MV and the MV apparatus as assessed by 2D echocardiography and fluoroscopy (Cormier score)
	Group 1	Group 2	Group 3
Anatomical characteristics	Pliable, noncalcified anterior mitral leaflet and midsubvalvular disease, that is, thin chordate 10 mm or longer.	Pliable noncalcified anterior mitral leaflet and severe subvalvular disease, that is, thickened chordate <10 mm long..	Calcification of mitral valve of any extent as assessed by fluoroscopy, whatever the state of the subvalvular apparatus is..
Interpretation of result	In a subset of 40 patients a Wilkins score in the range of 7–9 correlated with the echocardiographic group 1, a Wilkins score range 8–12 correlated with the echocardiographic group 2, and a Wilkins score range 10–15 with group.An echocardiographic grouping score of 2 or higher is associated with poor long-term results.
Assessment of commissural calciumThis method quantifies the extent of calcification in both commissures by giving a half commissure of each commissure a score of 1 with the detection of intensive bright echoes as seen by 2D TTE
Grade 1	Grade 2	Grade 3	Grade 4
Interpretation of result	Patients with a commissural calcium score grade 0–1were found to have larger MVA and an improvement in symptoms than those with grade 2–3 after PMBC. Commissural calcification is one of the strongest predictors of outcome of PMBC and may also predict severe MR as a major complication of PMBC.A commissural calcium grade of 2 or higher is a predictor of poor immediate results
Real-time transthoracic 3D echocardiographic score
Leaflets	AML			PML
Leaflet segments	A1	A2	A3	P1	P2	P3
Leaflet thickness (0–6) (0 = normal, 1 = thickened) a	0–1	0–1	0–1	0–1	0–1	0–1
Leaflet mobility (0–6) (0 = normal, 1 = thickened) a	0–1	0–1	0–1	0–1	0–1	0–1
Leaflet calcification (0–10)(0 = no, 1–2 = calcified) b	0–2	0–1	0–2	0–2	0–1	0–2
Subvalvular mitral apparatus b
Affected part of the subvalvular apparatus	Proximal third	Middle third	Distal third
Thickness (0–3) (0 = normal, 1 = thickened)	0–1	0–1	0–1
Separation (0–6) (0 = normal, 1 = partial, 2 = no)	0, 1, 2	0, 1, 2	0, 1, 2
Interpretation of result	a Normal = 0, mild = 1–2, moderate 3–4, severe 5–6 b Normal = 0, mild = 1–2, moderate 3–5, severe = 6The individual score points are added up, with the calculated total score ranging from 0–31 points. Mild MV involvement is defined as <8 points, moderate MV involvement 8–13, and severe MV involvement >14 points.
Echo score “Revisited” (to predict immediate outcome)
Echocardiographic variables	Points for score (0–11)
MVA ≤1 cm 2	2
Maximum leaflet displacement ≤12 mm	3
Commissural area ratio ≥1.25	3
Subvalvular involvement	3
Interpretation of result	3 risk groups are defined: low (score 0–3); intermediate (score 4–5); high (score 6–11). This score is more predictive than the Wilkins score and is particularly useful for predicting outcomes for patients categorized in the intermediate-risk group

AL, Anterolateral; AML, anterior mitral leaflet; MR, mitral regurgitation; MV, mitral valve; MVA, mitral valve area; PM, posteromedial; PML, posterior mitral leaflet; TTE , transthoracic echocardiography.

(Modified from Wunderlich NC, Dalvi B, Ho SY, et al. Rheumatic mitral valve stenosis: diagnosis and treatment options. Curr Cardiol Rep . 2019;21(3):14.)

Transesophageal echocardiography (TEE) can be performed to confirm the diagnosis in patients with poor acoustic windows and exclude a left atrial thrombus, which is an absolute contraindication for PMC; however, patients with organized thrombus deep into the left atrial appendage (LAA) can be treated with careful manipulation of catheter by avoiding entry into LAA. Other relative contraindications for PMC include severe thoracic deformity, bleeding diathesis, moderate mitral regurgitation (MR), concomitant severe coronary artery disease/aortic valve disease, and severe commissural mitral valve calcification. Severe MS is the class I indication for PMC and is an attractive option for all individuals where mitral valve replacement can be avoided, leading to multiple surgeries, especially in young patients. The burden of mitral prosthesis, and anticoagulation, especially in the case of mechanical mitral valve, cannot be underestimated. This is particularly a useful strategy in women of childbearing age so that they can complete their families and reduce complications during pregnancy. In patients with symptomatic MS and unsuitable anatomy for PMC, the decision to perform PMC must be individualized, taking into account the surgical risks and long-term demerits of a mitral prostheses. PMC is an appealing option in young patients with sinus rhythm and unfavorable anatomy. PMC can be considered in asymptomatic patients to allow pregnancy in young women or undergo urgent noncardiac surgery. PMC is also appropriate in asymptomatic patients with resting pulmonary hypertension or individuals who are at a higher risk of embolic events or hemodynamic decompensation. Exercise echocardiography can sometimes help delineate the asymptomatic from the symptomatic patients. A pulmonary pressure of more than 60 mm Hg during exercise can be considered an indication for PMC.