Year : 2021 Month : May Volume : 10 Issue : 18 Page : 1275-1279

Morphometric Study of Mitral Valve in South Odisha - A Cadaveric Study

Niharika Padhy1, Madhusmita Panda2

1Department of Anatomy, MKCG Medical College and Hospital, Berhampur, Odisha, India.
2Department of Anatomy, SCB Medical College and Hospital, Cuttack, Odisha, India.

CORRESPONDING AUTHOR

Dr. Madhusmita Panda, Associate Professor, SCB Medical College and Hospital, Cuttack, Odisha, India.
Email : drmpandascbanatomy@gmail.com

ABSTRACT

BACKGROUND

The heart is a pair of valved muscular pumps combined in a single organ. For the proper functioning of the heart, all valves should be intact. Mitral valve (MV) prolapse and regurgitation is the main cause of MV replacement. The dimensions of mitral valve and the cusps vary from person to person. We wanted to measure the average size of the valve components with respect to the annulus in the cadavers of South Odisha region, which would help in the selection of prosthetic valve in cardiac surgery.

 

METHODS

This comparative study was carried out on 58 adult cadaveric human hearts. Left atrium was opened along the left border of heart so as to expose the mitral orifice. Parameters of different components of the valve were measured by using appropriate instruments.

 

RESULTS

The mean annular circumference of the mitral valve was found to be 8.84 ± 1.24 cm; The annular attachment and height of anterior cusp were 2.94 ± .81 cm and 2.55 ± 0.27 cm respectively. The annular attachment and height of posterior cusp were 4.52 ± 0.78 cm and 1.2 ± 0.17 respectively. The annular area was found to be 5.22 ± 1.13 cm2. The combined cusp area was found to be 9.38 ± 2.32 cm.2

 

CONCLUSIONS

The size of mitral valve parameters in the South Odisha region were found to be less compared to other studies. This study might help cardio-thoracic surgeons as well as the prosthetic valve manufacturing companies for the rough estimation of the mitral valve size.

 

KEY WORDS

Mitral Valve, Anterior Cusp, Posterior Cusp, Annular Circumference, Annular Valve Area and Combined Cusp Area

BACKGROUND

The heart is a valvular muscular pump present in the middle mediastinum. For the proper functioning of the heart, all the valves should be intact1. Mitral valve prevents the backflow of blood into the left atrium. The mitral valve complex consists of mitral orifice and its associated annulus, the cusps, the supporting chordae tendineae, and papillary muscles. Mechanical support is provided by fibro elastic cardiac skeleton.

The mitral valve is described as consisting of a continuous veil attached around the entire circumference of the mitral orifice. Its free edge bears several indentations; two are sufficiently deep and regular to be named as anterolateral and posteromedial commissures.1

The anterior / aortic cusp is seen to guard one third of the circumference, having semi-circular or triangular in shape with few or no marginal indentation. The posterior / mural leaflet is regarded as the valvular tissue posterior to the anterolateral and posteromedial commissures. The extent of the commissural area is defined by noting the spread of insertion of the fan-like commissural chordal branches.2

Thus, defined the posterior leaflet has a wider attachment to the annulus, guarding two thirds of the circumference,1,2 it also rules out existence of extra cusps as observed by some workers. The indentations divide the posterior cusp into three scallops, the middle being the largest1, Raghunatha metal2 observed in 92 % hearts the posterior cusp was tri-scalloped, and the middle scallop was largest in 84 % of hearts.

Various heart diseases affect the valves causing stenosis, regurgitation or prolapse of leaflets resulting in valve insufficiency. Such cardiac diseases require repair of the valve; and when damage of the valve is more due to disease pathology, valve replacement surgery will be attempted with the artificial valve.3

Conservative mitral valve repair surgery with preservation of annulo-papillary muscle continuity by retaining the subvalvular apparatus whenever possible is gaining popularity as it provides excellent long-term results with increased survival rates as compared with the replacement of the valve especially in mitral regurgitation cases. As operation for the correction of mitral incompetence and grossly stenosed valve becomes more common, a better understanding of the detailed anatomy of the mitral valve and its functional correlation is the need of the hour.

For the mitral valve surgery to be successful attention has to be given to the exact dimension of each valvular component, otherwise there will be further structural deformity of the repaired valve or valve prosthesis-patient mismatch in case of replacement.

The mitral valve parameters, now a days are measured using modern imaging techniques. There is a gradual increase in annular size during diastole to maximum in late diastole after p-wave and the minimal size reached in systole.4 Hence, details of the morphometry of mitral valve can be studied manually. The quantitative data obtained by imaging method is also comparable to the direct anatomical or surgical measurements.5

Many publications dealing with the detailed anatomy are found in literature, but most of these works were done outside Odia population.

So, we wanted to measure the different parameters of the mitral valve cusps and annulus, which would be helpful to the cardiothoracic surgeons to determine the type and size of the prosthetic mitral valve which would be appropriate for the population of South Odisha suffering from mitral valve disease.

METHODS

The comparative study was conducted from January 2019 to December 2020 on fifty-eight adult hearts (without any obvious pathology) procured from the collection of embalmed cadavers available in the Department of Anatomy, M.K.C.G. Medical College & Hospital, Berhampur. Since the heart specimens were already removed from the cadavers before the commencement of the study, the sex could not be ascertained. The heart after removing the clots were washed thoroughly under tap water. The two atria were removed from ventricles by dissecting along the line of atrio- ventricular groove. The position of the four valvular orifices and the fibrous skeleton (the right and left fibrous trigones) were identified at the base of the ventricles.

The mitral valve complex was exposed by opening the left ventricular cavity by excising the right ventricle and then giving an incision along the postero-medial commissure and the inter ventricular septum. No papillary muscles were attached to the left side of the ventricular septum.

 

 

Parameters of the Study

  • The annular circumference was measured at the base of leaflets, by using a surgical silk thread.
  • Annular radius was derived by using geometrical formula 2πr (assuming the annulus to be roughly circular).1 The area of the mitral orifice (πr2) was computed manually.
  • The width of each leaflet at its annular attachment was measured using the surgical silk thread.
  • The height of each leaflet was measured from base to free edge in the central axis, in case of posterior leaflet, the height of middle scallop was used for measurement, since it is the largest scallop. It was measured by a pair of dividers.
  • The area of each leaflet was derived by using the formula ½ × base × height, assuming the leaflets to be roughly triangular.
  • The commissural depth and width were measured by using a pair of dividers. The extent of the commissure was defined by noting the spread of insertion of the fan like commissural chordalbranches.2

 

 

Statistical Analysis

Parameters were analysed statistically by using SPSS software. Students ‘t’ test was used for calculations.

RESULTS

 Many researchers have measured the parameters of cadaveric hearts. Our observations are compared with those of other workers in Table 1 and 2.

 

 

 

The mean annular circumference of the mitral valve was found to be 9.84 ± 1.24 cm; the annular attachment and height of anterior cusp were 2.94 ±0.81 cm and 2.55±0.27 cm respectively. The annular attachment and height of posterior cusp were 4.52 ±0.78 cm and 1.2 ±0.17 respectively. Width and depth of antero-lateral commissure were 0.53 ± 0.18 and 0.86 ± 0.25 respectively; for posteromedial commissure these values were 0.63 ± 0.15 and 0.73 ± 0.16 respectively. The annular area was found to be 5.22 ± 1.13 cm2. The combined cusp area was found to be 9.38 ± 2.32 cm2.

DISCUSSION

The mean annular circumference was found 8.84 (± 1.24) cm. 76 % of our observations lie between 9.2 to 10.1 cm. The findings of other workers range between 7.5 to 12.5 cm. According to Grey1 it is 9.0 in males and 7.5 in females. The measurements found by imaging technique also falls in this range. The annular attachment of anterior cusp was found to be 2.94 ± .81 cm. The values of other researchers vary between 2.5 - 4.8 mm. The annular attachment of the posterior cusp was 4.52 ± .78 cm. The findings of other researchers showed a wide range from 3.1 - 8.7 cm.8,10-14

However, Raghunathan2 and Khanna S.K11 have calculated the attachment of individual scallops, still combinedly, the measurement appears to be greater than 4.4 cm. Our findings are corroborative with the lower range of other studies. The anterior cusp bears no scallops in all the hearts studied. This is similar to the observation made by Raghunathan et al.2

The height of anterior cusp was 2.55 ± .27 cm and the findings of previous workers is in the range of 1.6 - 3.0 cm. The height at middle scallop was determined to be 1.2 ± .17 cm. Others have determined it to be between 0.8 - 2.5 mm.2,6-15,18,20,22.

The width of the antero-lateral commissure and postero- lateral commissure were 0.53 ± 0.18 cm and 0.63 ± 0.15 cm respectively.

 

 

 

The measurements collected from others range between 0.6 - 2.4 cm for antero-lateral and 0.7 - 2.6 cm for postero-medial commissures. The value obtained in the present work lies in the lower part of the range given by other researchers.2,8,11-15

The depth of the antero-lateral commissure and postero- lateral commissure were 0.86 ± 0.25 cm and 0.73 ± 0.16 cm respectively. The value obtained in the present work lies in the lower part of the range given by other researchers.2,7,8,11

 

 

In present study, the annular area was found to be 5.22 ± 1.13 cm.2 Others have obtained it to be between 426.1 to 793.0 mm.2 Francesco Maffessanti,25 determined it as 9.1 - 10.8 by imaging technique. Federico Veronesi26 found that the mitral annulus surface area was 8.0 ± 2.1 cm2 at end-diastole and decreased to 7.7 ± 2.1 cm2 in systole, reaching its maximum (10.0 ± 2.2 cm2) at mitral valve opening. Our findings are much less in comparison to the values obtained by imaging techniques. However, the values obtained by Ormiston4 agree with our findings.

The anterior cusp area was 3.45 ± .38 cm2 and the posterior cusp area was 3.76 ± .44 cm2. The findings of Cheichi et al.8 is 4.27 - 4.83 cm2 and 2.70 - 5.32 cm2 and that of Du Plessis et al.10 was 4.90 cm2 and 5.00 cm2 respectively for the anterior and posterior cusp areas. The areas of the two cusps are comparable despite the variations in their annular attachment and height, with the area of the posterior cusp being marginally high, corroborative with the findings of Du Plessis.10 The anterior cusp, however seems to cover the majority of the annulus plane surface in systole, even though the two leaflets have almost equal areas.27

The combined cusp area was found to be 9.38 ± 2.32 cm2. The finding of Chiechi9 was 697 - 1265 mm2 and of Du Plessis10 was 990 mm.2 S. L. Mautner28 found mitral leaflet area 8.7 ± 2.0 cm2 by imaging method. Our findings agree with the findings of others.

The combined surface areas of both the mitral valve leaflets is almost twice as greater than the area of mitral orifice, permitting a larger area of coaptation.6,9,11,29 Quain24 found the annular area: valve area to be 1:1.5 - 1: 2.2. This relation is maintained in our study

CONCLUSIONS

In the present study, efforts have been made to determine the dimensions of the normal mitral valve and compare them with the findings of other studies from different regions and times.

Irrespective of the type of study (imaging, autopsy and cadaveric), the valve size in our findings fall in the lower part of the range observed by other researchers. The annular area: combined cusp area is well maintained.

We agree with Mishra P.P,18 that a correction factor needs to be worked out so that imaging parameters and fixed valve measurement match with each other.

There has been a steady advance in the field of surgical intervention for mitral valve disease. Increasing cooperation between the medical professionals and their engineering counterparts has led to development of newer and better prosthetic valves. Hence, a detailed and comprehensive knowledge of the structure of the mitral valve complex with its functional correlation is necessary, thereby justifying its anatomical study.

All the indices and correlations between the measurements are of great value and must be taken into account while making different types of mitral valve prosthesis in bioengineering as a single type cannot solve the purpose.

REFERENCES

1

Standring S. Gray’s Anatomy. The anatomical basis of clinical practice. 41st edn. Elsevier/ Churchill Livingstone 2008: p. 970.

2

Ranganathan N, Lam JH, Wigle ED. Morphology of human mitral valve. II. The valve leaflets. Circulation 1970;41(3):459-67.      

CrossRef | Google Scholar | PubMed
3

Gopal MR, Taha A, John V, et al. Pediatric valve replacement, 15 years experience in Oman. Indian J Thorac Cardiovasc Surg 2006;22:173-7.       

Google Scholar |
4

Ormiston JA, Shah PM, Tei C, et al. Size and motion of the mitral valve annulus in man. 1. A bio-dimensional echocardiographic method and findings in normal subjects. Circulation 1981;64(1):113-20

CrossRef | Google Scholar | PubMed
5

Garbi M, Monaghan MJ. Quantitative mitral valve anatomy and pathology. Echo Res Pract 2015;2(3):R63-72.                       

CrossRef | Google Scholar | PubMed
6

Brock RC. The surgical and pathological anatomy of the mitral valve. Br Heart J 1952;14(4):489-513.                    

CrossRef | Google Scholar | PubMed
7

Rusted IE, Scheifley CH, Edwards JE. Studies of the mitral valve. I. Anatomic features of the normal mitral valve and associated structures. Circulation 1952;6(6):825-831.           

CrossRef | Google Scholar | PubMed
8

Chiechi M, Lees WM, Thomson R. Functional anaomy of the normal mitral valve. J Thorac Surg 1956;32(3):378-98.                  

Google Scholar | PubMed
9

Morris EW. Some features of the mitral valve. Thorax 1960;15(1):70-3. 

CrossRef | Google Scholar | PubMed
10

Du Plessis LA, Merchand P. The anatomy of the mitral valve and its associated structures. Thorax 1964;19(3):221-7.             

CrossRef | Google Scholar | PubMed
11

Khana SK. Morphology of the mitral valve. Indian Heart Journal 1975;28(1)          

12

Carpentier A, Guerinon J, Deloche A, et al. Pathology of the mitral valve. In: Kalmanson D, edr. The mitral valve: a pluridisciplinary approach. Massachusetts: Sciences Group Inc., 1976: p. 65-77.

13

Sakai T, Okita Y, Ueda Y, et al. Distance between mitral anulus and papillary muscles: anatomic study in normal human hearts. J Thorac Cardiovasc Surg 1999;118(4):636-41.       

CrossRef | Google Scholar | PubMed
14

Patil DS, Mehta CD, Prajapati PA. Morphology of mitral valve in human cadavers. Internet Journal of Cardiology 2008;7(2):1-8.    https://print.ispub.com/api/0/ispub-article/11285

15

Gunnal SA, Farooqui MS, Wabale RN. Study of mitral valve in human cadaveric hearts. Heart Views 2012;13(4):132-5.           

CrossRef | Google Scholar | PubMed
16

Gupta C, Shetti VR, Manju BVM. Dimensions of the human adult mitral valve in the embalmed cadaver. J Morphol Sci 2013;30(1):6-10.           

CrossRef | Google Scholar |
17

Deopujari R, Sinha U, Athavale SA. Anatomy of left atrioventricular valve (Mitral Valve) leaflets in adult Indian cadavers. Int J Morphol 2013;31(4):1276-81.     

Google Scholar |
18

Mishra PP, Rao MP, Paranjape V, et al. Morphometry of mitral valve. Medical Journal of Dr. D. Y. Patil Vidyapeeth 2014;7(5):625-30.           

Google Scholar |
19

Charanya N,  Rajathi G, Vishali N. Morphological and morphometrical analysis of mitral valve annulus of heart in human adult cadavers. Int J Anat Res 2017;5(3.3):4405-9.             

CrossRef |
20

Ilankathir S, Sakthivel S. Morphometry of mitral valve in south Indians-a cadaveric study. National Journal of Basic Medical Sciences 2017;8(1):5-9.      

Google Scholar |
21

van Wijngaarden SE, Kamperidis V, Regeer MV, et al. Three-dimensional assessment of mitral valve annulus dynamics and impact on quantification of mitral regurgitation. Eur Heart J Cardiovasc Imaging 2018;19(2):176-84.           

CrossRef | Google Scholar | PubMed
22

Sriambika K, Nim VK, Bage NN. Morphological and morphometric study of mitral valve with reference to anatomical variability in south indian subjects. Int J Anat Res 2018;6(4.3):5994-97.       

CrossRef | Google Scholar |
23

Geethanjali BS, Jayanthi V, Kaviman I, et al. The anatomical study of mitral valve annulus in the human cadaveric hearts for bioprosthesis. International of Journal of Anatomy and Research 2019;7(2.2):6575-80.

24

Walmsley T. The Heart. In: Sharpey-Schafer E, Symington J, Bryce TH, eds. Quain's elements of Anatomy. Pt - 3. Vol. 4. 11th edn. London: Longmans, Greens and Co., 1929: p. 42.

25

Maffessanti F, Gripari P, Pontone G, et al. Three-dimensional dynamic assessment of tricuspid and mitral annuli using cardiovascular magnetic resonance. Eur Heart J Cardiovasc Imaging 2013;14(10):986-95.                    

CrossRef | Google Scholar | PubMed
26

Veronesi F, Corsi C, Sugeng L, et al. A study of functional anatomy of aortic-mitral valve coupling using 3D matrix transesophageal echocardiography. Cir Cardiovasc Imaging 2009;21(2):24-31.           

CrossRef | Google Scholar | PubMed
27

McAlpine WA. Heart and coronary arteries. An anatomical atlas for clinical diagnosis, radiological investigation and surgical treatment. New York: Springer-Verlag 1965: p. 39-56.

28

Mautner SL, Klues HG, Mautner GC, et al. Comparison of mitral valve dimensions in adults with valvular aortic stenosis, pure aortic regurgitation and hypertrophic cardiomyopathy. Am J Cardiol 1993;71(11):949-53.             

CrossRef | Google Scholar | PubMed
29

Dal-Bianco JP, Levine RA. Anatomy of the mitral valve apparatus-role of 2D and 3D echocardiography. Cardiol Clin 2013;31(2):151-64.                  

CrossRef | Google Scholar | PubMed

DISCLOSURE AND FUNDING

Disclosure forms provided by the authors are available with the full text of this article at jemds.com

ICMJE Forms

Data sharing statement provided by the authors is available with the full text of this article at jemds.com.

Financial or other competing interests: None.

Disclosure forms provided by the authors are available with the full text of this article at jemds.com.

DATA SHARING STATEMENT

A data sharing statement provided by the authors is available with the full text of this article at jemds.com

How to cite this article

Padhy N, Panda M. Morphometric study of mitral valve in South Odisha - a cadaveric study. J Evolution Med Dent Sci 2021;10(18):1275-1279, DOI: 10.14260/jemds/2021/270

Videos :

watch?v