Description and prevalence of ventricular mitral annular disjunction: variation of normality or pathological variant?

INTRODUCTION AND OBJECTIVES

The aim of this study was to investigate a new variation of the atrial wall-mitral annulus-ventricular wall junction along the mural mitral leaflet and commissures: the ventricular mitral annular disjunction (v-MAD). This new variant is characterized by spatial displacement of the mitral leaflet hinge line by more than 2mm toward the left ventricle.

METHODS

We examined a cohort of autopsied human hearts (n=224, 21.9% females, 47.9±17.6 years) from patients without known cardiovascular disease to identify the presence of v-MAD.

RESULTS

More than half (57.1%) of the hearts showed no signs of MAD in the mural mitral leaflet or mitral commissures. However, v-MAD was found in 23.6% of cases, located within 20.1% of mural leaflets, 2.2% in superolateral commissures, and 1.3% in inferoseptal commissures. V-MAD was not uniformly distributed along the mitral annulus circumference, with the most frequent site being the P2 scallop (19.6% of hearts). The v-MAD height was significantly greater in mural leaflets than in commissures (4.4 mm±1.2 mm vs 2.1 mm±0.1 mm; P<.001). No specific variations in mitral valve morphology or anthropometrical features of donors were associated with the presence or distribution of v-MADs. Microscopic examinations revealed the overlap of the thin layer of atrial myocardium over ventricular myocardium in areas of v-MAD.

CONCLUSIONS

Our study is the first to present a detailed definition and morphometric description of v-MAD. Further studies should focus on the clinical significance of v-MAD to elucidate whether it represents a benign anatomical variant or a significant clinical anomaly.

Mitral regurgitation outcomes after transcatheter atrial septal defect closure

BACKGROUND

Worsening mitral regurgitation (MR) is a complication of intervention for atrial septal defect (ASD). Little is known about mitral valve (MV) characteristics associated with worsening MR. We aimed to elucidate MR outcomes and predictors of worsening MR after transcatheter ASD closure.

METHODS

We analyzed changes in MR from prior to transcatheter ASD closure to 6 months after the procedure and predictors of worsening MR via baseline transthoracic echocardiography in 238 patients (64.7% females; mean age, 53 ± 22 years).

RESULTS

Worsening MR was defined as worsening to moderate in patients with less than or equal to mild MR at baseline or vena contracta width increasing of ≥2 mm by 6-month follow-up in patients with moderate MR. Worsening MR was observed in 29 patients (12.2%). The associated echocardiographic findings were pseudoprolapse, hamstringing, stiffness, and anteroposterior and intercommissural mitral annulus diameter in the univariable logistic regression analysis (all P < 0.05). Multivariable analysis after adjusting for age; long-standing persistent atrial fibrillation; and ASD size showed that models combining MV leaflet findings such as pseudoprolapse or hamstringing, or anterior leaflet stiffness with the ratio of the sum of anterior and posterior leaflet lengths to intercommissural mitral annulus diameter were statistically significant for predicting worsening MR (R2 = 0.393, P < 0.001 and R2 = 0.385, P < 0.001, respectively).

CONCLUSIONS

Worsening MR after transcatheter ASD closure might depend on MV leaflet findings and annulus size in patients with long-standing persistent atrial fibrillation.

Extensive calcification of the mitral valve annulus in transcatheter aortic valve implants

 

OBJECTIVES

This study sought to report the calcification pattern of the mitral valve annulus and its implications for procedural and safety outcomes in transcatheter aortic valve implantation.

METHODS

Between November 2018 and September 2019, a total of 305 patients had transcatheter aortic valve implants at our institution. The extent of calcification of the mitral valve annulus was analysed, and the impact on safety outcomes was evaluated.

RESULTS

The prevalence of mitral annular calcification (MAC) was 43%. Calcification of the mitral valve annulus was either less than or at least one-third of the posterior annulus (34% and 32%), the whole posterior annulus (28%) or the extension to the attachment of the anterior leaflets (7%). Severe circumferential MAC revealed moderate paravalvular leaks in 5/8 (63%) patients and was associated with right branch bundle block [odds ratio (OR) 2.01 (0.39–3.06); P = 0.098] and low cardiac output [OR 3.12 (1.39–7.04); P = 0.033]. Subannular calcification at the anterolateral trigonum represented a risk factor for left ventricular outflow tract injury [OR 3.54 (1.38–8.27); P = 0.001] in balloon-expandable valves, associated with relevant rhythm disorders [OR 2.26 (1.17–5.65); P = 0.014] and female gender (7/8, 88%). The 30-day all-cause mortality in circumferential MAC reaching into the anterior annulus (grade IV) compared to patients with less MAC (grade I–III) was 13% vs 2% with a mean valve size of 24.6 vs 25.7 mm.

CONCLUSIONS

Extensive MAC was associated with moderate paravalvular leaks, with implications for the prosthesis size and survival in transcatheter aortic valve implants. In severe MAC, we recommend implanting oversized self-expandable prostheses, the goal being to reduce the risk of right branch bundle block and paravalvular leaks.

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122, 125

Transcatheter indirect mitral annuloplasty induces annular and left atrial remodelling in secondary mitral regurgitation

Aims

Mitral annuloplasty using the Carillon Mitral Contour System (CMCS) reduces secondary mitral regurgitation (SMR) and leads to reverse left ventricular remodelling. The aim of this study was to evaluate the effect of the CMCS on the mitral valve annulus (MA) and left atrial volume (LAV).

Methods and results

We retrospectively evaluated the data of all patients treated with the CMCS at our centre. Using transthoracic echocardiography, MA diameters were assessed by measuring the anterolateral to posteromedial extend (ALPM) and the anterior to posterior (AP) dimensions, respectively. Also, LAV and left ventricular end‐diastolic volume (LVEDV) were assessed. Patients were examined at three time points: baseline, at 20–60 days (30dFUP), and at 9–15 months (1yFUP), using paired analysis. From July 2014 until March 2019, 75 cases of severe SMR were treated using CMCS. Cases in which other devices were used in combination (COMBO therapy, n = 35) or in which the device could not be implanted (implant failure, n = 3) were excluded, leaving 37 patients in the present analysis. Analysis at 30dFUP showed a significant reduction of 16% in the mean ALPM diameter (7.27 ± 5.40 mm) and 15% in the AP diameter (6.57 ± 5.33 mm). Analysis of LAV also showed a significant reduction of 21% (36.61 ± 82.67 mL), with no significant change in LVEDV. At 1yFUP, the reduction of both the mean ALPM diameter of 14% (6.24 ± 5.70 mm) and the mean AP diameter of 12% (5.46 ± 4.99 mm) remained significant and stable. The reduction in LAV was also maintained at 23% (37.03 ± 56.91 mL). LAV index was significantly reduced by 17% at 30dFUP (15.44 ± 40.98 mL/m²) and by 13% at 1yFUP (11.56 ± 31.87 mL/m²), respectively. LVEDV index showed no significant change at 30dFUP and a non‐significant 10% reduction at 1yFUP (17.75 ± 58.79 mL/m²).

Conclusions

The CMCS successfully treats symptomatic SMR with a stable reduction of not only the AP diameter of the MA, but the current study also demonstrates an additional reduction of the ALPM dimension at both 30dFUP and 1yFUP. We have also shown for the first time that LAV and LAV index are significantly reduced at both 30dFUP and 1yFUP and a non‐significant positive remodelling of the LVEDV. This positive left atrial remodelling has not been looked for and demonstrated in earlier randomized studies of CMCS.

Validation of a Holographic Display for Quantification of Mitral Annular Dynamics by Three-Dimensional Echocardiography

BACKGROUND

Three-dimensional (3D) echocardiography with multiplanar reconstruction (MPR) is used clinically to quantify the mitral annulus. MPR images are, however, presented on a two-dimensional screen, calling into question their accuracy. An alternative to MPR is an autostereoscopic holographic display that enables in-depth visualization of 3D echocardiographic data without the need for special glasses. The aim of this study was to validate an autostereoscopic display using sonomicrometry as a gold standard.

METHODS

In 11 anesthetized open-chest pigs, sonomicrometric crystals were placed along the mitral annulus and near the left ventricular apex. High-fidelity catheters measured left atrial and ventricular pressures. Adjustments of pre- and afterload were done by constriction of the inferior vena cava and the ascending aorta, respectively. Three-dimensional epicardial echocardiography was obtained from an apical view and converted to the autostereoscopic display. A 3D virtual semitransparent annular surface (VSAS) was generated to measure commissure width (CW), septal-lateral length, area of the mitral annular surface, nonplanarity angle, and the annular height-to-commissure width ratio in mid-systole and late diastole.

RESULTS

Mitral annular measurements from the 3D VSAS derived from the 3D echocardiographic images and autostereoscopic display correlated well with sonomicrometry over a range of loading conditions: CW length (r = 0.98, P < .00001), septal-lateral length (r = 0.98, P < .00001), annular surface area (r = 0.93, P < .001), nonplanarity angle (r = 0.87, P < .001), and annular height-to-commissure width ratio (r = 0.85, P < .01). The 3D VSAS showed better agreement with the sonomicrometric measurements compared with MPR.

CONCLUSIONS

Mitral annular measurements using 3D VSAS correlate well with sonomicrometry over a range of loading conditions and may represent a powerful tool for noninvasive quantification of mitral annular dynamics.

Geometric comparison of the mitral and tricuspid valve annulus: Insights from three dimensional transesophageal echocardiography

AIM

To apply real time three-dimensional transesophageal echocardiography (RT3D TEE) for quantitative and qualitative assessment of the mitral valve annulus (MVA) and tricuspid valve annulus (TVA) in the same patient.

METHODS

Our retrospective cohort study examined the MVA and TVA in 49 patients by RT3D TEE. MVA and TVA shape were examined by TEE. The MVA and TVA volume data set images were acquired in the mid esophageal 4-chamber view. The MVA and TVA were acquired separately, with optimization of each for the highest frame rate and image quality. The 3D shape of the annuli was reconstructed using the Philips^® Q lab, MVQ ver. 6.0 MVA model software. The end-systolic frame was used. The parameters measured and compared were annular area, circumference, high-low distances (height), anterolateral-posterolateral (ALPM), and anteroposterior (AP) axes.

RESULTS

A total of 49 patients (mean age 61 ± 14 years, 45% males) were studied. The ALPM and the AP axes of the MVA and TVA are not significantly different. The ALPM axis of the MVA was 37.9 ± 6.4 mm and 38.0 ± 5.6 mm for the TVA (P = 0.70). The AP axis of the MVA was 34.8 ± 5.7 mm and 34.9 ± 6.2 mm for the TVA (P = 0.90). The MVA and the TVA had similar circumference and area. The circumference of the MVA was 127.9 ± 16.8 mm and 125.92 ± 16.12 mm for the TVA (P = 0.23). The area of the MVA was 1103.7 ± 307.8 mm² and 1131.7 ± 302.0 mm² for the TVA (P = 0.41). The MVA and TVA are similar oval structures, but with significantly different heights. The ALPM/AP ratio for the MVA was 1.08 ± 0.33 and 1.09 ± 0.28 for the TVA (P < 0.001). The height for the MVA and TVA was 9.23 ± 2.11 mm and 4.37 ± 1.48 mm, respectively (P < 0.0001).

CONCLUSION

RT3D TEE plays an unprecedented role in the management of valvular heart disease. The specific and exclusive shape of the MVA and TVA was revealed in our study of patients studied. Moreover, the intricate codependence of the MVA and the TVA depends on their distinctive shapes. This realization seen from our study will allow us to better understand the role valvular disease plays in disease states such as hypertrophic cardiomyopathy and pulmonary hypertension.