Segmental analysis of aortic basal ring dimensions in normal and dilated tricuspid aortic roots

OBJECTIVES

In patients with aortic root aneurysm, the aortic basal ring is frequently dilated. It has been speculated that the muscular part of the basal ring dilates most. The purpose of this study was to analyse the segmental dilatation of the basal ring, comparing normal and dilated roots in patients with tricuspid aortic valves.

METHODS

Retrospective analysis of computed tomography studies in patients with normal and dilated aortic roots was performed. Lengths of segments of the basal ring corresponding to each of the 3 sinuses, and to the muscular and fibrous parts were measured. Fractions of these segments relative to the total basal ring perimeter were calculated.

RESULTS

We analysed 152 normal and 126 dilated aortic roots and 86 propensity-matched pairs. Basal ring dilatation was present in all segments of dilated aortic roots with subtle differences between the segments corresponding to the 3 sinuses. The muscular part of the basal ring dilated proportionately to its fibrous part, with no difference in fractions of measured muscular part in normal and dilated roots [42.2% (interquartile range 4.3%) vs 42.1% (interquartile range 6.3%)].

CONCLUSIONS

Basal ring dilatation was present in all segments corresponding to the 3 sinuses in dilated aortic roots. Both muscular and fibrous parts dilated equally, supporting the need to stabilize the entire basal ring when performing aortic valve repair surgery.

A toolbox for generating scalable mitral valve morphometric models

The mitral valve is a complex anatomical structure, whose shape is key to several traits of its function and disease, being crucial for the success of surgical repair and implantation of medical devices. The aim of this study was to develop a parametric, scalable, and clinically useful model of the mitral valve, enabling the biomechanical evaluation of mitral repair techniques through finite element simulations. MATLAB was used to parameterize the valve: the annular boundary was sampled from a porcine mitral valve mesh model and landmark points and relevant boundaries were selected for the parameterization of leaflets using polynomial fitting. Several geometric parameters describing the annulus, leaflet shape and papillary muscle position were implemented and used to scale the model according to patient dimensions. The developed model, available as a toolbox, allows for the generation of a population of models using patient-specific dimensions obtained from medical imaging or averaged dimensions evaluated from empirical equations based on the Golden Proportion. The average model developed using this framework accurately represents mitral valve shapes, associated with relative errors reaching less than 10% for annular and leaflet length dimensions, and less than 24% in comparison with clinical data. Moreover, model generation takes less than 5 min of computing time, and the toolbox can account for individual morphological variations and be employed to evaluate mitral valve biomechanics; following further development and validation, it will aid clinicians when choosing the best patient-specific clinical intervention and improve the design process of new medical devices.

Geometric description for the anatomy of the mitral valve: A review

The mitral valve is a complex anatomical structure whose physiological functioning relies on the biomechanical properties and structural integrity of its components. Their compromise can lead to mitral valve dysfunction, associated with morbidity and mortality. Therefore, a review on the morphometry of the mitral valve is crucial, more specifically on the importance of valve dimensions and shape for its function. This review initially provides a brief background on the anatomy and physiology of the mitral valve, followed by an analysis of the morphological information available. A characterisation of mathematical descriptions of several parts of the valve is performed and the impact of different dimensions and shape changes in disease is then outlined. Finally, a section regarding future directions and recommendations for the use of morphometric information in clinical analysis of the mitral valve is presented.

Novel Trigone-Based Sizing Method for Mitral Ring Annuloplasty

BACKGROUND

We devised a novel trigone-based sizing method, setting the trigones at one-quarter of the annular circumference, and used it for mitral annuloplasty in patients with mitral regurgitation (MR).

METHODS

Between 1999 and 2017, 436 patients with degenerative (n = 192), nonischemic functional (n = 124), or ischemic (n = 120) MR underwent mitral valvuloplasty at our institution using an incomplete ring. The intertrigonal distance and prerepair and postrepair annular diameter were measured. Then the diameters predicted from body surface area, the intertrigonal distance, and the ratios of these diameters to observed data were computed. We investigated the influence of these measurements on MR recurrence, transmitral pressure gradient, and systolic anterior motion.

RESULTS

Initial repair was successful in 433 patients (99%), but 3 patients with systolic anterior motion and MR required conversion to valve replacement. After 1, 5, and 10 years (mean follow-up, 6.3 years), the rate of freedom from grade 2 or higher recurrent MR was 96%, 92%, and 86% in the degenerative group, 99%, 97%, and 90% in the nonischemic functional group, and 95%, 90%, and 79%, respectively, in the ischemic group (P = .052). The observed/body surface area predicted diameter ratio was negatively correlated with the mean transmitral pressure gradient (mm Hg); 12.3 - 8.2 × (ratio) (R = -0.37, P < .001), despite a smaller ratio (<0.9) not being associated with less recurrence of MR. In the degenerative group, systolic anterior motion developed in 7 of 71 patients (10%) with an observed/intertrigonal distance predicted diameter ratio of less than 0.9 (P < .001).

CONCLUSIONS

Our trigone-based sizing method achieved satisfactory control of MR, while avoiding functional mitral stenosis and systolic anterior motion.

Study of the normal heart size in Northwest part of Iranian population: a cadaveric study

Introduction: The heart is in a muscular organ in the middle mediastinum. According to our knowledge, there is no standard data about the anthropologic parameters of normal Iranian hearts. Hence, the aim of the present study was to investigate the normal heart size in Iranian cadavers.

Methods: In a cross-sectional study, 550 cadavers (104 female/446 male) from June 2014 to July 2015 in the Razavi Khorasan province of Iran were included in the study. After approval of the Ethical Committee, cadavers were divided into 10 groups based on age groups. Length, width, weight, chordae tendineae, papillary muscles, and heart valves were measured using vernier caliper. Finally, data were analyzed using SPSS software.

Results: The mean values of the demographic data were as follows: age= 42.12 ± 21.34 years; weight = 60.38 ± 15.32 kg; height = 158.14 ± 23.77 cm; and BMI = 24.66 ± 17.60 kg/m². The mean values of the heart length, width, chordae tendineae, pupillary muscles, weight, and index of the heart were 11.41 ± 2.15 cm, 8.21 ± 4.38 cm, 19.41 ± 6.70, 5.74 ± 1.96, 247.78 ± 62.27 grams, and 5.74 ± 1.96, respectively. In addition, the circumference of the tricuspid valve, circumference of the mitral valves, and tricuspid and mitral areas were 8.80 ± 1.11 cm, 9.43 ± 1.44 cm, 4.11 ± 0.71 cm², and 4.50 ± 0.90 cm², respectively.

Conclusion: Mean values of the heart’s length and width was similar to previous reports from western population. The circumference of the tricuspid valve was less than the textbook’s data, while circumference of the mitral valves was more than it. The study findings provide valuable information about standard data of the heart in the Iranian population, which is useful for surgeons as well as anthropologists. However, multi-center studies with a larger sample size are required to complete data about anatomical characteristics of normal hearts.

Non-ischaemic mitral valve suture annuloplasty: late follow-up results

Objective:

To evaluate late outcomes after posterior mitral valve (MV) annulus double-suture annuloplasty for degenerative (non-ischaemic) MV insufficiency.

Design:

Between 2005 and 2011, 138 patients underwent MV repair using posterior MV double-suture annuloplasty and an additional 105 patients underwent tricuspid valve repair. The study protocol included operative mortality, reoperation rate and reasons, as well as echocardiographic parameters at pre- and postoperative and follow-up periods (2-9 years).

Results:

In-hospital mortality was 2/138 (1.45%). Early post operation, no regurgitation was noted in 74/136 (54.4%) patients, Io regurgitation was observed in 55/136 (40.4%), IIo was observed in 6/136 (4.4%) and IIIo was observed in 1/136 (0.7%); during late follow-up (from 2 to 9 years), no regurgitation was observed in 21.6% patients, Io was observed in 58%, IIo was observed in 17% and IIIo was observed in 3.4%. The mean preoperative anterolateral diameter of the MV annulus was 39.02±4.97 mm and, at late follow-up, it was 27.66±3.94 mm (p=0.000); at these same time points, left ventricular end-diastolic diameter (LVEDD) was 55.74±7.29 mm and 49.17±6.01 mm (p=0.000), respectively, and the left ventricular ejection fraction (LVEF) was 53.08±8.93% and 50.92±6.78%, respectively (p=0.007).

Conclusions:

This study demonstrates suture annuloplasty to be an effective treatment up to 9 years for degenerative mitral valve disease. This technique enables preservation of the posterior mitral valve annulus diameter with stable long-term (up to 9 years) reduction, a competent (no regurgitation/⩽IIo regurgitation) MV in 96.6% of cases and positive left ventricular (LV) remodelling.

Standard transthoracic echocardiography and transesophageal echocardiography views of mitral pathology that every surgeon should know

The mitral valve is the most commonly diseased heart valve and the prevalence of mitral valve disease increases proportionally with age. Echocardiography is the primary diagnostic imaging modality used in the assessment of patients with mitral valve disease. It is a noninvasive method which provides accurate anatomic and functional information regarding the mitral valve and can identify the mechanism of mitral valve pathology. This is especially useful as it may guide surgical repair. This is increasingly relevant given the growing trend of patients undergoing mitral valve repair. Collaboration between cardiac surgeons and echocardiographers is critical in the evaluation of mitral valve disease and for identification of complex valvular lesions that require advanced surgical skill to repair. This article will provide an overview of transthoracic and transesophageal assessment of common mitral valve pathology that aims to aid surgical decision making.

Mitral valve anatomy: implications for transcatheter mitral valve interventions

Mitral regurgitation is a common valvular heart disease and its prevalence is expected to increase with population ageing. Percutaneous techniques for the treatment of mitral regurgitation are emerging as an alternative therapeutic option. However, the mitral valve is a complex structure, and a comprehensive understanding of the anatomy of the mitral valve apparatus and its surrounding structures is crucial for a correct selection of patients and the success of transcatheter mitral valve interventions.

Results of mitral valve annuloplasty with a standard-sized posterior band: is measuring important?

OBJECTIVE

This study was undertaken to determine hemodynamic and clinical outcomes of annuloplasty with a standard-sized (63 mm) posterior band in adult patients undergoing mitral valve repair for degenerative valve disease.

METHODS

We studied 511 patients who underwent isolated mitral valve repair for degenerative disease with a 63-mm posterior band used for annuloplasty. Operations were performed between 1994 and 2001, and average follow-up was 4.8 +/- 3.1 years. Echocardiographic data were reviewed, with specific focus on the relationship between patient size and residual mitral regurgitation and gradient.

RESULTS

Mean age at the time of operation was 59.3 +/- 13.5 years, and 72% were male. Body mass index was 25.8 +/- 4.1 kg/m(2), and body surface area was 1.97 +/- 0.24 m(2). Preoperative mean ejection fraction was 64% +/- 7%, and 96% of patients had severe mitral regurgitation on preoperative echocardiography. The 30-day mortality was 0.8%. At hospital discharge, the mean gradient was 4.7 +/- 3.1 mm Hg. Body surface area, body mass index, and weight were not associated with postoperative gradients or residual regurgitation at discharge. At last follow-up, 89% of patients had no or mild regurgitation, and the mean ejection fraction was 58% +/- 9%. At 5 years, survival was 95% and cumulative risk of reoperation was 3%.

CONCLUSION

A standard-sized (unmeasured) posterior annuloplasty band provided excellent intermediate results with good durability. There were neither excess gradients in larger patients nor excess regurgitation in smaller patients. Measured annuloplasty is unnecessary for most adults undergoing mitral valve repair.