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Morphometry of Mitral Valve Leaflet for Reconstructive Surgery in Human Cadaveric Hearts of South Indian Population |
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Geethanjali Savalgi, V Jayanthi, JP Shruthi, H Mohan Kumar 1. Professor and Head, Department of Anatomy, Sapthagiri Institute of Medical Sciences and Research Centre, Bangalore, Karnataka, India. 2. Principal and Dean, Department of Anatomy, Sapthagiri Institute of Medical Sciences and Research Centre, Bangalore, Karnataka, India. 3. MBBS Student, Department of Anatomy, East Point Institution of Medical Sciences and Research Centre, Bangalore, Karnataka, India. 4. Professor and Head, Department of Opthalmology, Sapthagiri Institute of Medical Sciences and Research Centre, Bangalore, Karnataka, India. |
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Correspondence Address : Dr. Geethanjali Savalgi, No. 45, 5th Cross, Malagal, Bangalore, Karnataka, India. E-mail: geethamohan76@gmail.com |
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ABSTRACT | |||||||||||||||||||||||||||||||||||||||||||||||||||
: The pumping capacity of heart is affected by disorders involving the valves of the heart. The mitral valve in human cadaveric heart comprises of annulus, leaflets, chordae tendinae and papillary muscle. Aim: To find morphometric analysis of normal mitral valve leaflets in the cadaveric hearts for the conservative surgical techniques. Materials and Methods: The morphometric observational analysis was done on 50 heart of embalmed adult human cadaver of both sexes (28 males, 22 females) age between 20-60 years which were taken from the Department of Anatomy during 2016-2018 in Vydehi Institute of Medical Science and Research Centre, Bangalore, Karnataka, India. Parameters measured were length and breadth of anterior and posterior leaflet, length of anterior and posterior commissure, and length of free edge of both leaflets of mitral valve. Descriptive statistical analysis was done and Mean±SD (Standard Deviation) (Min-Max) and percentage of parameters was calculated by using statistical software Statistical Package for the Social Sciences (SPSS) version 15.0. Results: The mean length of anterior and posterior mitral valve leaflets was 1.99±0.35 cm and 1.25±0.22 cm, respectively, breadth of anterior and posterior mitral valve leaflets was 2.84±0.47 cm and 4.00±0.53 cm. The length of anterior leaflet was more than posterior leaflet. Breadth of posterior leaflet was more than anterior leaflets. Length of anterior commissure (0.65±0.11 cm) was more than posterior commissure (0.64±0.08 cm) in males. Conclusion: On the basis of the findings of the present study, the morphometric parameters of mitral valve leaflet was important for cardiac Surgeons during operation to assess the exact mechanical reason for valve insufficiency and in manufacture of prosthesis for mitral valve replacement. | |||||||||||||||||||||||||||||||||||||||||||||||||||
Keywords : Clefts, Chordae tendinae, Commissures, Scallops, Valve replacement | |||||||||||||||||||||||||||||||||||||||||||||||||||
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INTRODUCTION | |||||||||||||||||||||||||||||||||||||||||||||||||||
The mitral orifice is a well defined transitional zone between the atrial wall and the bases of the cusps. It lies posterior, inferior and slightly to the left of aortic valve. The orifice has two cusps and resembles to bishop’s mitre, hence the name is given as bicuspid valve or mitral valve. Mitral annulus is an area where anterior and posterior leaflets were attached to junction of atrial and ventricular chamber. The anterior leaflet occupy one third of annulus whereas posterior occupy two third of annulus (1). The junction of anterior and posterior leaflets has indentations known as anterior and posterior commissures. The chordae tendinae arises from the papillary muscles was attached to both leaflets of the mitral valve. The two mitral valve leaflets are actually a single continuous structure that becomes confluent at the commissures. Indentations was absent in anterior leaflet when compared to posterior leaflet. The posterior leaflet has three indentations of which the middle indentation was larger and has two smaller indentations on either side of it (2). Anterior leaflet provides smooth contoured surface for the streamlined ejection of blood flow through the left ventricle outflow tract (3). Identification of the individual scallops of posterior leaflet was significant in cases of prolapsed posterior leaflet with mitral regurgitation (4). The posterior commissurotomy more often was followed by a surgically produced valvular incompetence. No commissurotomy should ever reach the mitral ring, because of the importance of maintaining a cuff of valvular tissue to ensure the closure of the orifice (5). The mitral valve insufficiency may result from the diseases of heart which affects the valves like stenosis, regurgitation of valves or prolapse of the leaflets. The function of mitral valve depends on the anatomical and mechanical integrity of the atrioventricular ring, the valve leaflets, chordae tendinae and the papillary muscles (6). The diseased valve of the patient is replaced by a prosthetic valve. The prosthetic valve was made of metal or tissue type. The metal type is made up of stainless steel alloys, molybdenum, pyrolytic carbon, silicon, teflon or polyster (7). The comparative evaluation of study group of right atrioventricular valve showed similar values when evaluated by fixed, non fixed and echocardiograms (8). This knowledge of measurement of mitral valve leaflet may be useful for cardio thoracic surgeons in mitral valve replacement (9). Thus, the aim of the current study was to do a morphometric analysis of normal mitral valve leaflets in the cadaveric hearts for the conservative surgical techniques. | |||||||||||||||||||||||||||||||||||||||||||||||||||
MATERIAL AND METHODS | |||||||||||||||||||||||||||||||||||||||||||||||||||
The morphometric observational study was done on 50 hearts (28 male, 22 female) aged between 20-60 years, taken from previously embalmed adult human cadaver from the Department of Anatomy, Vydehi Institute of Medical Sciences and Research Centre, Bangalore, Karnataka, India, during the period for 36 months from January 2016 to December 2018. Inclusion criteria: Cadaveric heart without previous history of cardiac surgery was included for the study. Exclusion criteria: Cadaveric heart with previous history of cardiac surgery such as coronary artery bypass surgery, valvular surgery was excluded from the study. Dissection of Specimen Position and orientation of each heart and its chambers was confirmed by anatomical position of heart. Left atrium was opened and the mitral valve was inspected from above. The left ventricle inflow tract was cut open along the inferolateral aspect through left atrial wall, through the anterolateral commissure of mitral valve between two papillary muscles to reach the apex (9),(10). In each heart, detailed examination of the measurements of the mitral valve, by using vernier calliper manual type, measuring scale, cotton thread, magnifying lens. In each cadaveric heart following parameters of mitral valve was noted, number of leaflets in each valve, number of clefts and scallops of posterior leaflet, variations in the cleft and indentation in each cusp of the mitral valve was observed. The length of anterior and posterior leaflet was measured from free edge to its attachment to the annulus by calliper. The breadth of anterior and posterior leaflet was measured at the line of insertion at the valve ring by calliper. The length of free margin of both anterior and posterior leaflets was measured by cotton thread along the free edge of both the leaflets. The number and length of each commissure was measured by calliper. The basal zone was identified by attachment of chordae tendinae arising from ventricular wall to posterior leaflet. These observations were found in all 50 specimens of cadaveric hearts taken for the study is represented in (Table/Fig 1) (2). The basal zone was identified only in posterior leaflets. The rough zone was visualised towards apex of leaflets as a crescentric area which was thicker on palpation and was attached to chordae tendinae on the ventricular surface. The clear zone was identified towards the annulus and was smooth without any chordae tendinae attached to its ventricular surface (Table/Fig 2) (2). STATISTICAL ANALYSIS Descriptive statistical analysis was done. The result were presented as mean and Standard Deviation (SD) and percentage by using statistical software SPSS 15.0 (11). | |||||||||||||||||||||||||||||||||||||||||||||||||||
RESULTS | |||||||||||||||||||||||||||||||||||||||||||||||||||
In each heart, a detailed examination of mitral valve was done and different parameters were measured [Table/Fig-(3),(4),(5),(6) and results are tabulated in (Table/Fig 7). In the present study, the mean length of anterior leaflet was 2±0.36 cm in males and 1.98±0.29 cm in females. The length of posterior leaflet was 1.29±0.24 cm in males and 1.20±0.18 cm in females. The breadth of anterior leaflet was 2.85±0.55 cm in males and 2.83±0.32 cm in females. The breadth of posterior leaflet was 3.99±0.58 cm in males and 4.01±0.43 cm in females. The length of anterior commissure was 0.65±0.11 cm in males and 0.60±0.05 cm in females and length of posterior commissure was 0.64±0.08 cm in both male and female. The free edge of leaflet was 9.42±1.26 cm in males and 9.41±1.19 cm in females. All the parameters of mitral valve were greater in males except breadth of posterior leaflets which was more in females. The length of anterior commissure was more than posterior commissure in males, length of posterior commissure was equal both in males and in females. The length of anterior leaflet was more compared to posterior leaflets and breadth of posterior leaflets was more compared to anterior leaflets both in male and females. The edge of the anterior leaflet was smooth and there was no indentation. It was triangular in shape. Free edge of the posterior leaflet showed 2 clefts and 3 indentations in all 50 specimens. The middle indentation was large in all the specimens. The rough zone and clear zone was identified in both the anterior and posterior leaflets. | |||||||||||||||||||||||||||||||||||||||||||||||||||
DISCUSSION | |||||||||||||||||||||||||||||||||||||||||||||||||||
When compared to other studies the mean length of anterior leaflets was more compared to posterior leaflets and mean breadth of anterior leaflets was less compared to posterior leaflets in all the studies including the present study (Table/Fig 8) (4),(6),(9),(10),(12),(13),(14),(15),(16),(17),(18),(19),(20),(21),(22). In the present study mean length of anterolateral and posterolateral commissure was less compared to other studies (Table/Fig 9) (4),(5),(6),(10),(16),(17),(18),(20),(21),(22),(23),(24). The anterior commissure length was more in males than in females in the present study and also in a few studies where relevant data for the same was provided [Table/Fig10] (4),(5),(6),(12),(13),(15),(19),(20),(24). The mean length of free edge of both leaflets was more than the studies of Du Plussis LA and Marchand P and Patil DS et al., (Table/Fig 11) (16),(18). Improper valve prosthesis replacement may worsen the cardio vascular problems thus these normal morphometric measurement of mitral valve help cardiothoracic surgeon in identifying correct size of the prosthesis for valve replacement like valvotomy, commisurotomy, valvuloplasty (9). Limitation(s) Agewise measurement of parameters of leaflets of mitral valve was not done for precise dimension of mitral valve leaflets for cardiothoracic surgeons during mitral valve reconstruction surgeries. The formalin fixation may alter the size of valve measurement in exact prosthesis manufacture. | |||||||||||||||||||||||||||||||||||||||||||||||||||
CONCLUSION | |||||||||||||||||||||||||||||||||||||||||||||||||||
The present study showed mean value of length of anterior and posterior mitral valve leaflets and breadth of anterior mitral valve leaflets and length of anterior commissure was more in males compared to females except breadth of posterior leaflets was more in females and posterior commissure was equal in both male and female. Length of anterior commissure was more than posterior commissure. Accurate knowledge about the normal anatomy of the mitral valve complex is needed in assessing the valve pathology and in manufacture of prosthetic valve replacements during surgical interventions like valvotomy, Valvectomy and valvuloplasty. | |||||||||||||||||||||||||||||||||||||||||||||||||||
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