Variation of anatomical structures related to biventricular pacing procedures and cannulation of the coronary sinus

The success of biventricular pacing procedures is at least partially related to the ability to implant leads into the heart. Lead placement into the coronary sinus can be particularly challenging because of variations in the coronary venous anatomy. We examined the anatomy of the coronary sinus and the Thebesian valve. Forty-three (22 male, 21 female) embalmed adult cadavers were used to determine the internal diameter of the coronary sinus ostium, the presence of a membranous or fenestrated Thebesian valve, and the percent occlusion of the coronary sinus ostium by the Thebesian valve, if present. An 8-French (F) guiding catheter was used to simulate coronary sinus cannulation. The average internal diameter of the coronary sinus ostium was 11.44 ± 3.21 mm. A Thebesian valve was present in 74 % of the cadavers, and the majority (84 %) of those valves were membranous. In the presence of a Thebesian valve, the opening at the ostium was reduced to 7.47 ± 2.69 mm. The percent occlusion of the coronary sinus ostium by the Thebesian valve varied from 8.26 to 100 %. The average cannulation distance (length of catheter travel into the coronary sinus from the coronary sinus ostium) was 69 ± 18 mm. Statistical analyses revealed no gender differences in the measurement data for either the coronary sinus or Thebesian valve. The most common presentation is a membranous Thebesian valve. Most frequently, the percent occlusion ranged between 41 and 50 %. The cannulation distance was greater in males than in females.     

The Thebesian valve: Gatekeeper to the coronary sinus

Clinical cardiac procedures such as electrophysiology studies, catheter ablation of arrhythmias, retrograde cardioplegia delivery, cardiac resynchronization therapy and, more recently, percutaneous mitral annuloplasty, involve cannulation of the coronary sinus (CS). The presence of a membrane closing the orifice of the CS may cause difficulties during these interventions. Thus, detailed knowledge of the variations and anomalies of the valve of the CS, or the Thebesian valve, now has practical significance. To improve our understanding of this structure, classic anatomical dissection of 50 hearts from dissection room cadavers was performed. A Thebesian valve was present in the overwhelming majority (88%) of cases. Its morphology varied widely, from a few small strands of tissue, to a membrane covering more than half the CS ostium. A significant number (20%) of valves occluded >65% of the ostium, making them "potential complicating factors" in cannulation of the CS. An understanding of these anatomical variations may help in identifying and overcoming potential difficulties during clinical cardiac interventions.     

Anatomical landmarks for locating the sphenoid ostium during endoscopic endonasal approach: a cadaveric study

Purpose

The sphenoid ostium (SO) provides a natural portal for entering the sphenoid sinus and beyond up to the skull base. It is not always easy to locate the ostium during the endoscopic approach. The present study was designed to establish readily identifiable anatomical landmarks for locating the sphenoid ostium.

Methods

Cadaveric dissection was performed in 30 hemisections of head and neck and various measurements were taken from fixed anatomical landmarks in the nasal cavity to the sphenoid ostium. The size, shape and position of sphenoid ostium were determined in relation to the anterior wall of the sphenoid sinus and the superior turbinate.

Results

The mean distance from the supero-lateral angle of the posterior choana to the SO was found to be 21.21 ± 6.02 mm. The mean distance of the SO from the midline was 4.85 ± 2.89 mm. In all the specimens, the SO was situated within 1 cm of the midline. The mean distance between the inferior end of the SO and the postero-inferior edge of the superior turbinate was 8.03 ± 3.52 mm. The SO was present on an average distance of 55.1 ± 3.54 mm from the limen nasi. In 93.3 % of the specimens, the SO was situated between 5 and 6 cm of the inferior end of the limen nasi. The angle between the anterior nasal spine and the SO was found to be remarkably constant. In 93.3 % of the specimens, it was from 25° to 30°.

Conclusions

The sphenoid ostium could be localized medial to the superior turbinate between 1.5 and 3 cm above the supero-lateral angle of the posterior choana, within 1 cm of the midline and within 1 cm of the postero-inferior edge of the superior turbinate.     

Developmental aspects of the sinus valves and the sinus venosus septum of the right atrium in human embryos

Summary In 32 human embryos from 5 to 27 mm of length, stages 13 to 23 (according to the Carnegie system of stages), the contributions of the sinus venosus septum and the right sinus valve of the right atrium to the formation of the Eustachian and Thebesian valve were examined by scanning electron microscopy. The sinus septum takes part in the subdivision of the right sinus valve into the Eustachian and the Thebesian valves. From its first origin the sinus septum forms a septal structure between the orifices of the right hepatic vein (hepatic portion of the inferior caval vein), the precursor of the inferior caval vein, and the left horn of the sinus venosus, the precursor of the coronary sinus. Before the incorporation of the sinus venosus into the right atrium, it has an intra-sinusal position, and extends between the bases of the left and the right sinus valve. During the incorporation of the sinus venosus into the right atrium the sinus septum receives an intra-atrial position, and its positional relationships to the sinus valves and the orifices of the corresponding veins remain unchanged in principle. Due to the connection between the sinus septum and the right sinus valve, after completion of the incorporation of the sinus, the superior portion of the right sinus valve branches y-like into a lateral limb, (i.e. its original inferior portion) and into a medial limb, (i.e. the sinus septum). Thus, the Eustachian valve is formed by the superior portion of the right sinus valve and the sinus septum; whereas the Thebesian valve is formed by the inferior portion of the right sinus valve. The normal variations in the configuration of the Eustachian and the Thebesian valves are supposed to be caused by differential growth of the constituents of the different portions of the valves. This work was supported by the Stiftung Volkswagenwerk (I/63 363). Gratefully dedicated to Professor Erich Blechschmidt on the occasion of his 85th birthday     

山羊心脏二尖瓣复合体的应用解剖学研究

目的观测山羊心脏二尖瓣复合体的解剖结构,为比较解剖学积累资料。方法利用大体解剖方法观测山羊二尖瓣复合体的形态结构。结果山羊心脏二尖瓣复合体由二尖瓣瓣环、瓣膜、腱索和乳头肌构成,二尖瓣瓣环周长为47.00±7.39mm,前瓣的高度为7.93±2.03mm,宽度为21.58±4.17mm,后瓣的高度为9.89±1.90mm;宽度分别为20.61±4.22mm;前乳头肌起始点至前瓣、后瓣和后内侧连合的腱索条数分别为5.06±1.71,3.19±1.11,1.25±0.48;后乳头肌起始点附着于前瓣、后瓣和前外侧连合的腱索条数分别为4.50±1.88,4.16±1.84,1.32±0.54。结论山羊心脏二尖瓣复合体的结构与人类相似,但形态有特异性。     

Automatic segmentation of the aortic root in CT angiography of candidate patients for transcatheter aortic valve implantation

Transcatheter aortic valve implantation is a minimal-invasive intervention for implanting prosthetic valves in patients with aortic stenosis. Accurate automated sizing for planning and patient selection is expected to reduce adverse effects such as paravalvular leakage and stroke. Segmentation of the aortic root in CTA is pivotal to enable automated sizing and planning. We present a fully automated segmentation algorithm to extract the aortic root from CTA volumes consisting of a number of steps: first, the volume of interest is automatically detected, and the centerline through the ascending aorta and aortic root centerline are determined. Subsequently, high intensities due to calcifications are masked. Next, the aortic root is represented in cylindrical coordinates. Finally, the aortic root is segmented using 3D normalized cuts. The method was validated against manual delineations by calculating Dice coefficients and average distance error in 20 patients. The method successfully segmented the aortic root in all 20 cases. The mean Dice coefficient was 0.95 ± 0.03, and the mean radial absolute error was 0.74 ± 0.39 mm, where the interobserver Dice coefficient was 0.95 ± 0.03 and the mean error was 0.68 ± 0.34?mm. The proposed algorithm showed accurate results compared to manual segmentations.     

Congenital malformations of the semilunar valves

Normal semilunar valves develop at the downstream end of the embryonic cardiac tube by remodeling of the endocardial cushion material. Two valves, each with three commissures, form by subdivision of the two larger (lateral) of the four endocardial cushions. In this study congenitally malformed semilunar valves from autopsy heart specimens were reviewed to determine whether the lesions could be explained as deviations of normal valvulogenesis. The morphological spectrum of raphes and their occasional occurrence at the site of separation between the two lateral cushions, an obligatory commissure, suggested that they are usually the result of fusion of previously formed commissures. In 306 hearts there were 316 malformed semilunar valves: 208 pulmonic and 108 aortic. Four categories of lesions were found: (1) 27 atretic valves could not be interpreted; (2) 6 valves were quadricuspid with an extra commissure; (3) 45 valves showed failure of formation of one (44) or two (1) commissures; and (4) 238 valves showed fusion of one (156), two (22), or three (60) commissures as indicated by the presence of raphes. In 27 instances an atretic valve was too small to evaluate. Thus, evidence that three leaflets had at one time been present, as determined by the count of commissures plus raphes, was found in 82 per cent of interpretable valves. Several associated congenital cardiac lesions (coarctation of the aorta, transposition of the great vessels, tetralogy of Fallot, mitral atresia) exhibited a highly significant association with either aortic or pulmonic valvular malformations. The findings suggest that the majority of congenital malformations of the semilunar valves are due to lesions acquired in utero subsequent to normal valvulogenesis. Disproportionate flow reduction of the right or left side of the heart may be a factor in the development of malformations in the respective semilunar valve.     

To what extent can 3D model replicate dimensions of individual mitral valve prolapse?

Determining the complex geometry of mitral valve prolapse is often difficult. We constructed 3D models of six prolapsed mitral valves for surgical assessment, and evaluated how accurately the models could replicate individual valve dimensions. 3D polygon data were constructed based on an original segmentation method for computed tomography images. The model’s replication performance was confirmed via dimensional comparison between the actual hearts during surgery and those models. The results revealed that the prolapsed segments matched in all cases; however, torn chordae were replicated in four cases. The mean height differences were 0.0 mm (SD 1.6, range ??2 to +?2 mm) for the anterolateral side, 0.0 mm (SD 1.7, range ??2 to +?2 mm) for the prolapsed leaflet center, and ??1.5 mm (SD 0.6, range ??1 to ??2 mm) for the posteromedial side. Regression analysis showed a strong and positive correlation, and Bland–Altman plots indicated quantitative similarity of the models to the actual hearts. We concluded that our 3D valve models could replicate the actual mitral valve prolapses within acceptable dimensional differences. Our concepts are useful for better 3D valve creation and better surgical planning with reliable 3D valve models.     

Anatomic data of the human coronary sinus

The authors studied the formation, tributaries, length and the ostium of the coronary sinus, as well as the relationship of the venous walls to the myocardium and to the epicardium. The observations were made out of 143 hearts of subjects of different ages, and it was found that the most frequent display of the coronary sinus valve was a semilunar form (52 adults, 15 youngsters, 2 children, 3 newborn); it was also found valves in a cribriform or septal form. The absence of the valve of coronary sinus was noted in 53 cases (42 adults, 9 youngsters, 2 newborn). The valve of Vieussens was found, in some cases, at the level of the transition between the great cardiac vein and the coronary sinus, as well as others single or double parietal venous valves. The action of the valve of coronary sinus is also discussed by the authors.     

Morphological alterations in the position of the mandibular foramen in dentate and edentate mandibles

The technique of inferior alveolar nerve (IAN) block must be based on precise anatomical knowledge regarding the correct position of the mandibular foramen (MF). The aim of the investigation reported here was to determine the anatomic and topographic localization of the MF according to mandibular ramus anatomic landmarks and to identify morphological alterations in the position of the MF and size and shape of the ramus in terms of the impact of tooth socket loss in the molar and premolar region. Seventy-three dry human adult mandibles were divided into two groups according to dental status. These were measured to determine the distances from the anterior and posterior ramus border (AB, PB) to the midpoint of the MF fossa, and from the mandibular notch (MN) and inferior ramus border (IB) to the MF entering point. A number of relevant ramus anatomic features were analyzed, such as ramus width (RW), height (RH), and thickness (RT). The MF was closer to the PB and IB in edentate mandibles (right/left mean PB-MF 10.66 ± 1.84/11.06 ± 2.05 mm; right/left mean IB-MF 21.77 ± 3.23/21.8 ± 2.27 mm) compared to dentate mandibles (right/left mean PB-MF 11.87 ± 2.08/12.04 ± 1.94 mm; right/left mean IB-MF 22.94 ± 3.09/22.74 ± 3.74 mm). Edentate mandibles demonstrated reduced RW (right/left mean RW 26.03 ± 3.53/26.49 ± 3.90 mm), significantly reduced (p = 0.03) right RH (right/left mean RH 43.56 ± 4.74/45.43 ± 4.86 mm), and significantly reduced (p < 0.05) RT in the area of the MF fossa depression (right/left mean RT 5.52 ± 1.21/5.21 ± 0.91 mm) compared to dentate mandibles (right/left mean RW 27.34 ± 3.84/27.48 ± 3.80 mm; right/left mean RH 46.33 ± 4.52/47.40 ± 4.20 mm; right/left mean RT 7.86 ± 1.98/8.10 ± 1.92 mm). Alterations in MF position and mandibular ramus anatomic features in edentate mandibles increase the potential risk of complications and failure of IAN block.     

The Development of the Semilunar Valves in the Human Heart

The development of human semilunar valves was studied in a range of specimens including embryos before the appearance of cellular semilunar valves at stage 17 and hearts after the attainment of mature fibroelastic valvular structure, which occurs around the time of birth. The valves develop by modification of endocardial cushion material at the downstream end of the cardiac tube and appear to grow at the margins, probably by cellular proliferation into a stagnant zone caused by boundary layer separation of blood flow. The flat endothelium on the ventricular aspect and the cuboidal endothelium on the arterial aspect of the valves correlate, respectively, with expected high and low shear forces produced by surface blood flow. Development of an aorta and pulmonary trunk with tricuspid semilunar valves appears to be contingent on the appearance of separate entwined ventricular ejection streams. The later fibroelastic phases of semilunar valve development show progressive increase in elastic and collagenous fibers, at sites which appear to be subjected, respectively, to fluctuating and static tensions.     

A Novel Coaptation Plate Device for Functional Mitral Regurgitation: An In Vitro Study

A novel mitral valve repair device, coaptation plate (CP), was proposed to treat functional mitral regurgitation. The objective of this study was to test efficacy of the CP in an in vitro model of functional mitral regurgitation. Ten fresh porcine mitral valves were mounted in a left heart simulator, Mitral regurgitation was emulated by means of annular dilatation, and the asymmetrical or symmetrical papillary muscles (PM) displacement. A rigid and an elastic CPs were fabricated and mounted in the orifice of regurgitant mitral valves. Steady flow leakage in a hydrostatic condition and regurgitant volume in a pulsatile flow were measured before and after implantation of the CPs. The rigid and elastic CPs reduced mitral valve regurgitant volume fraction from 60.5 ± 11.4 to 35 ± 11.6 and 36.5 ± 9.9%, respectively, in the asymmetric PM displacement. Mitral regurgitation was much lower in the symmetric PM displacement than in the asymmetric PM displacement, and was not significantly reduced after implantation of either CP. In conclusion, both the rigid and elastic CPs are effective and have no difference in reduction of functional mitral regurgitation. The CP does not aggravate mitral valve coaptation and may be used as a preventive way.     

Mast Cells in Human Stenotic Aortic Valves Are Associated with the Severity of Stenosis

Aortic valve stenosis (AS) is characterized by extensive calcification of the aortic valve leaflets and infiltration of inflammatory cells. Activated mast cells (MCs) may participate in the induction of fibrosis and calcification with ensuing valve stiffening. We sought to investigate whether the number of MCs within stenotic aortic valves is associated with the severity of AS. We studied 43 patients (19 men, 24 women) with dominant AS (age, 64.2?±?5.9 years; mean transvalvular pressure gradient, 62.11?±?24.47 mmHg) without atherosclerotic vascular disease, undergoing elective aortic valve replacement. MCs were detected in the excised valves by immunostaining. Aortic valves from five healthy subjects obtained on autopsy served as negative controls. The number of tryptase- and chymase-positive MCs was increased in AS valves compared with the control valves (6.9 [2.3–18.9]/mm² vs. 0.7 [0–2.2]/mm², P?=?0.0001 and 3.2 [2.1–9.4]/mm² vs. 0.3 [0–1.9]/mm², P?=?0.002, respectively). MCs that colocalized with macrophages and neovessels were detected mainly in the calcified regions of the leaflets. The number of MCs positively correlated with maximal (r?=?0.73, P?<?0.0001) and mean (r?=?0.78, P?<?0.0001) gradients and maximal aortic jet velocity (r?=?0.68, P?=?0.0005). An inverse correlation with aortic valve area (r?=??0.71, P?=?0.0001) was also observed. Multivariate regression analysis revealed that MC number and valve thickness were significantly associated with mean transvalvular gradient (R ²?=?0.74, P?<?0.000001) in AS patients. Increased MC number within human stenotic aortic valves is associated with the severity of AS.     

Anatomy of the valve of the coronary sinus (thebesian valve)

The valve of the coronary sinus was studied in 50 hearts from dissection room cadavers. It varied from a flap that covered up to 70% of the ostium of the coronary sinus, to a few small strands of tissue. In 3 cases no valve was present. In most cases (35 out of 50), the valve covered <50% of the ostium of the coronary sinus, so it is unlikely to play an important role in preventing reflux into the coronary sinus. Microscopically, the valve was found to contain layers of myocardium, most of which disappeared in the less well formed valves, but some myocardium was persistent even in the most rudimentary valves studied. © 1994 Wiley-Liss, Inc.     

Comparison of two spike areas in bileaflet mechanical valve closing sound

We previously reported our development of a wavelet analysis system which demonstrates that in vivo bileaflet mechanical valve sound splits into two spikes at higher frequency levels and, based on this system, proposed criteria for detecting malfunctioning bileaflet valves (MBVs). However, the results of that study were only tentative due to the small number of patients with MBVs enrolled in the study. Here, we discuss the possibility of new criteria based on the scalographic properties of two spikes of bileaflet valve sound. The study cohort comprised 12 patients who each received a Carbomedics valve. Based on cinefluoroscopy findings, seven valves were classified into a ??normal?? group, and the other five were classified into a ??malfunction?? group. Five consecutive valve sounds for each valve were collected for the wavelet analysis in order to re-evaluate the previously proposed criteria and to measure both anterior spike area (Aa) and posterior spike area (Pa) for calculating the spike area ratio (Aa/Pa). The proposed criteria, namely, a single spike or coefficient of variation of <0.1120 detected only two of the five malfunctioning valves, as well as one normal valve to be malfunctioning. The mean Aa/Pa of all malfunctioning valves [2.45?±?0.63; 95?% confidence interval (CI) ±1.01, 95?% confidence limits (CL) 1.44?C3.46] was significantly higher than that of all normal valves (1.17?±?0.27; 95?% CI ±0.25, 95?% CL 0.92?C1.42). Based on this result, we determined the cutoff value of Aa/Pa to be 1.4. The combination of a single spike on the scalogram and an Aa/Pa of >1.4 detected more MBVs than previously proposed criteria. This combination may represent new criteria for detecting MBVs.     

Comparison of long-term results between Hancock porcine bioprosthesis and Carpentier-Edwards pericardial bioprosthesis in the aortic and the mitral positions

The aim of this study was to compare the long-term results with the Carpentier-Edwards pericardial bioprosthesis, a second-generation bioprosthesis, and the Hancock porcine valve in the aortic and mitral position. Long-term results of isolated valve replacement with the Carpentier-Edwards pericardial bioprosthesis (73 valves in the aortic position and 73 valves in the mitral position) were compared with those with the Hancock porcine bioprosthesis (41 valves in the aortic and 124 valves in the mitral position). In the aortic position, the mean follow-up period was 8.2±4.0 years with the Carpentier-Edwards pericardial bioprosthesis and 9.9±4.4 years with the Hancock porcine bioprosthesis. In the mitral position, the mean follow-up period was 7.5±4.3 years with the Carpentier-Edwards pericardial bioprosthesis and 10.0±5.3 years with the Hancock porcine bioprosthesis. The results showed that the mean age at implantation was significantly higher in patients with a Carpentier-Edwards pericardial bioprosthesis (58±13 years in the aortic and 51±15 years in the mitral) than in those with a Hancock bioprosthesis (42±13 years in the aortic and 45±10 years in the mitral). In the aortic position, actuarial freedom from structural deterioration of the Carpentier-Edwards pericardial bioprosthesis was significantly better (85±6% at 13 years) than that with the Hancock bioprosthesis (40±10%,P<0.02). In the mitral position, actuarial freedom from structural deterioration of the Carpentier-Edwards pericardial bioprosthesis was similar to that with the Hancock bioprosthesis (32±9% and 44±6% at 13 years, respectively). It is concluded that the durability of the Carpentier-Edwards pericardial bioprosthesis in the aortic position was satisfactory in the elderly patients. In the mitral position, the superior durability of the Carpentier-Edwards pericardial bioprosthesis against the Hancock bioprosthesis failed to be proved.     

海绵窦上壁的应用解剖学研究

目的为经海绵窦(CS)上壁的手术提供解剖学资料。方法解剖观测15例(30侧)成人头颅标本CS上壁的解剖三角、脑膜及相关结构。结果①CS上壁为不规则的四边形,可分出3个解剖三角:颈动脉三角、动眼神经三角及前内侧三角;②动眼神经门的长径为(5.67±0.87)mm,短径为(1.09±0.35)mm;动眼神经鞘膜袋前深(4.69±1.31)mm,后深(6.50±1.58)mm;③上壁的脑膜结构有镰状韧带、前岩床皱襞、后岩床皱襞、床突间韧带,颈动脉床突韧带、颈动脉穴及颈动脉领、动眼神经鞘膜袋、远环及近环等,膜结构在前床突(ACP)尖形成复杂的膜复合体。结论CS上壁的解剖三角可作为CS的手术入路,其脑膜结构对于手术也具有重要意义。     

Anatomical study of the corrugator supercilii muscle and its clinical implication with botulinum toxin A injection

Purpose

Botulinum toxin A (BTX-A) injection targeting the corrugator supercilii muscle (CSM) has been widely performed to remove glabellar wrinkles. The aim of the present study was to elucidate the exact location and dimensions of the CSM in Koreans by elaborate dissections followed by accurate measurements to provide the topographic guidance for an efficient and safe manipulation of the BTX-A injection.

Methods

Thirty-five specimens from twenty fixed Korean cadavers (twelve males, eight females; mean age, 65.5 years) were examined in the present study.

Results

The CSM comprised oblique and transverse bellies, with the oblique belly being classified into narrow vertical (62.9 %) and broad triangular (37.1 %) types. The widths at the apex and base of the CSM were 10.0 ± 3.7 and 19.5 ± 5.4 mm (mean ± SD), respectively. The most-medial apical point was located 17.3 ± 3.2 mm superior to the horizontal intercanthal plane (HL) and 4.3 ± 1.9 mm lateral to the vertical midline of the face (VL). The most-lateral apical point was located 15.8 ± 2.4 mm superior to the HL and 13.9 ± 4.3 mm lateral to the VL. The most-medial basal point was located 31.2 ± 3.2 mm superior to the HL and 16.4 ± 4.8 mm lateral to the VL. The most-lateral basal point was located 28.6 ± 4.9 mm superior to the HL and 35.3 ± 4.3 mm lateral to the VL.

Conclusion

The topographic data on the CSM presented here in will be helpful for the accurate and safe implementation of BTX-A injection to the forehead in Koreans.     

山羊心脏三尖瓣复合体的解剖学特征

目的　观测山羊心脏三尖瓣复合体形态特征 ,为心脏研究和比较解剖学积累资料。方法　 1 0 %甲醛固定的山羊心脏 1 0 5例 ,解剖并观测三尖瓣复合体 ,保留隔缘肉柱和羊心腔特有结构。结果　山羊心脏三尖瓣复合体前瓣、后瓣 ,隔侧瓣的高度分别为 :8 4 3± 2 0 0mm、8 1 3± 1 90mm、7 6 8± 2 .1 0mm ;宽度分别为 :1 4 0 3± 3 1 6mm、1 4 35± 2 70mm、1 6 78± 3 4 6mm。前乳头肌腱索总条数为 :7 79± 1 72。后群乳头肌腱索条数为 :7 4 2± 2 1 7,后群乳头肌的个数为 2 36± 0 92。隔侧群乳头肌腱索总条数为 :1 0 4 2± 2 4 9,隔侧群乳头肌的个数为 4 0 5± 1 4 4。隔缘肉柱的长度为 9 5 3± 3 4 6mm。结论　山羊心脏三尖瓣复合体和人类心相似 ,但其心腔结构有其特异性