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Toshiharu Ishii - One of the best experts on this subject based on the ideXlab platform.
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settlement of stenotic site and enhancement of risk factor load for atherosclerosis in left anterior descending coronary artery by Myocardial Bridge
Arteriosclerosis Thrombosis and Vascular Biology, 2018Co-Authors: Yuri Akishimafukasawa, Yukio Ishikawa, Yoshikiyo Akasaka, Tetuo Mikami, Toshiharu IshiiAbstract:Objective— The aim of this study was to investigate the influence of a Myocardial Bridge (MB) on atherosclerosis development in the left anterior descending artery of the normal heart and the importance of traditional risk factors (RFs). An additional objective was to determine the correlation between intimal thickening and luminal narrowing. Approach and Results— The left anterior descending artery from 150 autopsied hearts was treated with formalin perfusion fixation, and each left anterior descending artery was serially cross-sectioned. The intima–media and luminal stenosis ratios were examined using computer-assisted histomorphometry. The luminal stenosis ratio was closely correlated with the intima–media ratio ( r =0.792; P P =0.022 by a multiple comparison test), but there were no differences between the RF (+) and RF (−) groups when an MB was absent. In addition, the site of the greatest stenosis in the MB (+) RF (+) group was 2.5 cm proximal to the MB entrance. Multivariate analyses indicated that age was an independent factor for luminal stenosis ratios ≥50% and 60% ( P =0.002 and 0.029, respectively). Furthermore, the presence of an MB plus RFs was an independent factor for a luminal stenosis ratio ≥70% ( P =0.037). Conclusions— An MB enhances left anterior descending artery atherosclerosis development at a site proximal to the MB entrance, particularly in subjects who have some RFs.
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Myocardial Bridge as a structure of double edged sword for the coronary artery
Annals of Vascular Diseases, 2014Co-Authors: Toshiharu Ishii, Yukio Ishikawa, Yoshikiyo AkasakaAbstract:Myocardial Bridge (MB) is a chance anatomical structure, comprised of the Myocardial tissue, with which the coronary artery running in epicardial adipose tissue is partly covered. It is predominantly present in the left anterior descending artery (LAD) and recognizable through imaging techniques as changes in blood flow within the LAD that arises from MB contraction at cardiac systole. Such changes in blood flow influence the pathophysiology of coronary circulation and atherosclerosis development, thus generating controversy as to whether MB predisposes individual to Myocardial infarction (MI). However, recent histomorphometric studies have shown that the individual anatomic properties of MB, such as location, length and thickness, consistently play a critical role in the occurrence of MI. This review article comprehensively addresses the pathophysiological mechanisms of MI occurrence together with the benign suppressive effect of coronary atherosclerosis by MB.
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association of variance in anatomical elements of Myocardial Bridge with coronary atherosclerosis
Atherosclerosis, 2013Co-Authors: Ami Iuchi, Yukio Ishikawa, Yoshikiyo Akasaka, Yuri Akishimafukasawa, Ryuji Fukuzawa, Toshiharu IshiiAbstract:Abstract Objectives The Myocardial Bridge (MB) is an anatomical structure consisting of myocardium covering a part of the left anterior descending coronary artery (LAD). The extent and spatial distribution of atherosclerosis in the LAD with an MB is influenced by the anatomical properties of the MB. In this study, the relationship between the overall anatomical framework of the MB including the periarterial adipose tissue as well as fibrosis of the MB itself and coronary atherosclerosis was histomorphometrically examined. Methods Full-length LADs with an MB from 180 autopsied hearts were cross-sectioned at 5-mm intervals. Together with measurements of MB – length, thickness, and location, proportional decrease of the atherosclerosis ratio of LAD segments beneath MB for that of LAD segments proximal to MB was defined as the atherosclerosis suppression ratio. The area ratio of adipose tissue in the periarterial area beneath MB and area ratio of fibrosis in the MB muscle were also measured. Results The atherosclerosis suppression ratio was significantly proportional to MB length and thickness. Periarterial adipose tissue beneath MB was detected in all cases (100%), and fibrosis within MB muscle for 136 cases (75.6%). The amount of adipose tissue beneath MB and MB fibrosis did not statistically affect the atherosclerosis suppression ratio. Multivariate analysis revealed MB length and thickness were the independent factors affecting the atherosclerosis suppression ratio. Conclusions The anatomical properties of an MB, especially of its length and thickness, play decisive roles as regulators of atherosclerosis in the LAD regardless of the amount of adipose tissue around LAD and MB fibrosis.
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significance of the anatomical properties of a Myocardial Bridge in coronary heart disease
Japanese Circulation Journal-english Edition, 2011Co-Authors: Yukio Ishikawa, Yoko Kawawa, Eiichi Kohda, Kazuyuki Shimada, Toshiharu IshiiAbstract:A Myocardial Bridge (MB), partially covering the coronary artery, is a congenital anatomical variant usually present in the left anterior descending coronary artery (LAD). MB causes coronary heart disease (CHD) by 2 distinct mechanisms influenced by the anatomical properties of the MB, such as its length, thickness, and location. One is direct MB compression of the LAD at cardiac systole, resulting in delayed arterial relaxation at diastole, reduced blood flow reserve, and decreased blood perfusion. The other is enhancement of coronary atherosclerosis causing stenosis of the LAD proximal to the MB, occurring because of endothelial injury arising from the abnormal hemodynamics provoked by retrograde blood flow up toward the left coronary ostium at cardiac systole. The magnitude of the effect of the 2 distinct mechanisms of the MB on LAD blood flow is prescribed by a common root of the MB-muscle mass volume generated by those properties. Furthermore, the anatomical properties of the MB are closely associated with the choice of treatment and therapeutic outcome in CHD patients having an MB. Thus, the anatomical properties of an MB should be considered in the diagnosis and management of CHD patients with this anomaly.
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anatomical characteristics of Myocardial Bridge in patients with Myocardial infarction by multi detector computed tomography
Japanese Circulation Journal-english Edition, 2011Co-Authors: Kazuhisa Takamura, Yukio Ishikawa, Toshiharu Ishii, Shinichiro Fujimoto, Shuji Nanjo, Rine Nakanishi, Shinji Hisatake, Atsushi Namiki, Junichi YamazakiAbstract:Background: Recent development of multi-detector computed tomography (MDCT) has made the detection of Myocardial Bridge (MB) easier on the left anterior descending coronary artery (LAD). The LAD segment proximal to the MB is well known to be susceptible to atherosclerosis. Anatomical characteristics of MB on LAD in patients with Myocardial infarction (MI) were examined by MDCT. Methods and Results: Subjects were 43 MI patients who had MB in the LAD and comprised 2 groups: 14 with culprit lesions in the LAD proximal to MB (culprit group) and 29 without culprit lesions in the LAD (non-culprit group). MB length, MB thickness, and the distance from the orifice of left main trunk (LMT) to MB entrance were compared. Age and coronary risk factors showed no significant difference between the 2 groups. MB length (P=0.011), MB thickness (P=0.035), and index of the length multiplied by thickness of MB (P=0.031) were significantly greater in the culprit group. The distance from the orifice of the LMT to MB entrance was significantly shorter in the culprit group (P=0.006). Conclusions: Anatomical properties of MB, such as length and thickness of MB as well as MB location, are associated with the formation of culprit lesions of LAD proximal to MB in MI. (Circ J 2011; 75: 642-648)
Yukio Ishikawa - One of the best experts on this subject based on the ideXlab platform.
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settlement of stenotic site and enhancement of risk factor load for atherosclerosis in left anterior descending coronary artery by Myocardial Bridge
Arteriosclerosis Thrombosis and Vascular Biology, 2018Co-Authors: Yuri Akishimafukasawa, Yukio Ishikawa, Yoshikiyo Akasaka, Tetuo Mikami, Toshiharu IshiiAbstract:Objective— The aim of this study was to investigate the influence of a Myocardial Bridge (MB) on atherosclerosis development in the left anterior descending artery of the normal heart and the importance of traditional risk factors (RFs). An additional objective was to determine the correlation between intimal thickening and luminal narrowing. Approach and Results— The left anterior descending artery from 150 autopsied hearts was treated with formalin perfusion fixation, and each left anterior descending artery was serially cross-sectioned. The intima–media and luminal stenosis ratios were examined using computer-assisted histomorphometry. The luminal stenosis ratio was closely correlated with the intima–media ratio ( r =0.792; P P =0.022 by a multiple comparison test), but there were no differences between the RF (+) and RF (−) groups when an MB was absent. In addition, the site of the greatest stenosis in the MB (+) RF (+) group was 2.5 cm proximal to the MB entrance. Multivariate analyses indicated that age was an independent factor for luminal stenosis ratios ≥50% and 60% ( P =0.002 and 0.029, respectively). Furthermore, the presence of an MB plus RFs was an independent factor for a luminal stenosis ratio ≥70% ( P =0.037). Conclusions— An MB enhances left anterior descending artery atherosclerosis development at a site proximal to the MB entrance, particularly in subjects who have some RFs.
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Myocardial Bridge as a structure of double edged sword for the coronary artery
Annals of Vascular Diseases, 2014Co-Authors: Toshiharu Ishii, Yukio Ishikawa, Yoshikiyo AkasakaAbstract:Myocardial Bridge (MB) is a chance anatomical structure, comprised of the Myocardial tissue, with which the coronary artery running in epicardial adipose tissue is partly covered. It is predominantly present in the left anterior descending artery (LAD) and recognizable through imaging techniques as changes in blood flow within the LAD that arises from MB contraction at cardiac systole. Such changes in blood flow influence the pathophysiology of coronary circulation and atherosclerosis development, thus generating controversy as to whether MB predisposes individual to Myocardial infarction (MI). However, recent histomorphometric studies have shown that the individual anatomic properties of MB, such as location, length and thickness, consistently play a critical role in the occurrence of MI. This review article comprehensively addresses the pathophysiological mechanisms of MI occurrence together with the benign suppressive effect of coronary atherosclerosis by MB.
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association of variance in anatomical elements of Myocardial Bridge with coronary atherosclerosis
Atherosclerosis, 2013Co-Authors: Ami Iuchi, Yukio Ishikawa, Yoshikiyo Akasaka, Yuri Akishimafukasawa, Ryuji Fukuzawa, Toshiharu IshiiAbstract:Abstract Objectives The Myocardial Bridge (MB) is an anatomical structure consisting of myocardium covering a part of the left anterior descending coronary artery (LAD). The extent and spatial distribution of atherosclerosis in the LAD with an MB is influenced by the anatomical properties of the MB. In this study, the relationship between the overall anatomical framework of the MB including the periarterial adipose tissue as well as fibrosis of the MB itself and coronary atherosclerosis was histomorphometrically examined. Methods Full-length LADs with an MB from 180 autopsied hearts were cross-sectioned at 5-mm intervals. Together with measurements of MB – length, thickness, and location, proportional decrease of the atherosclerosis ratio of LAD segments beneath MB for that of LAD segments proximal to MB was defined as the atherosclerosis suppression ratio. The area ratio of adipose tissue in the periarterial area beneath MB and area ratio of fibrosis in the MB muscle were also measured. Results The atherosclerosis suppression ratio was significantly proportional to MB length and thickness. Periarterial adipose tissue beneath MB was detected in all cases (100%), and fibrosis within MB muscle for 136 cases (75.6%). The amount of adipose tissue beneath MB and MB fibrosis did not statistically affect the atherosclerosis suppression ratio. Multivariate analysis revealed MB length and thickness were the independent factors affecting the atherosclerosis suppression ratio. Conclusions The anatomical properties of an MB, especially of its length and thickness, play decisive roles as regulators of atherosclerosis in the LAD regardless of the amount of adipose tissue around LAD and MB fibrosis.
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histopathologic profiles of coronary atherosclerosis by Myocardial Bridge underlying Myocardial infarction
Atherosclerosis, 2013Co-Authors: Yukio Ishikawa, Yoshikiyo Akasaka, Koyu Suzuki, Yuri Akishimafukasawa, Ami Iuchi, Mieko Uno, Eriko Abe, Yang Yang, Kiyoshi Mukai, Hitoshi NiinoAbstract:Abstract Objective Anatomic properties of Myocardial Bridge (MB) are sometimes responsible for Myocardial infarction (MI) through the changes in the atherosclerosis distribution in the left ascending coronary artery (LAD). The purpose of this study was to investigate histopathologic profiles of atherosclerotic lesions resulting from the MB presence in the LAD in the MI cases. Methods In 150 consecutive autopsied MI hearts either with MBs [MI(+)MB(+); n = 67] or without MBs [MI(+)MB(−); n = 83] and 100 normal hearts with MBs [MI(−)MB(+)], LADs were consecutively cross-sectioned at 5-mm intervals. The most advanced intimal lesion and unstable plaque-related lesion characteristics (UPLCs) in each section were histopathologically evaluated in conjunction with the anatomic properties of the MB, such as its thickness, length, location, and MB muscle volume burden (MMV: the total volume of MB thickness multiplied by MB length). Results The MB showed a significantly greater thickness ( P = 0.0090), length ( P = 0.0300), and MMV ( P = 0.0019) in MI(+)MB(+) than in MI(−)MB(+). Mean age of acute MI cases was significantly younger ( P = 0.0227) in MI(+)MB(+) than in MI(+)MB(−). Frequency of plaque fissure/rupture in the proximal LAD was significantly higher in acute MI cases of MI(+)MB(+) than in MI(+)MB(−). UPLCs tended to be located proximally in MI(+)MB(+) and frequent 2.0 cm or more proximal to the MB entrance in MI(+)MB(+). Conclusion In MI(+)MB(+), UPLCs tend to be located more proximally, and a plaque in the LAD proximal to the MB is prone to rupture, resulting in MI at younger age.
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significance of the anatomical properties of a Myocardial Bridge in coronary heart disease
Japanese Circulation Journal-english Edition, 2011Co-Authors: Yukio Ishikawa, Yoko Kawawa, Eiichi Kohda, Kazuyuki Shimada, Toshiharu IshiiAbstract:A Myocardial Bridge (MB), partially covering the coronary artery, is a congenital anatomical variant usually present in the left anterior descending coronary artery (LAD). MB causes coronary heart disease (CHD) by 2 distinct mechanisms influenced by the anatomical properties of the MB, such as its length, thickness, and location. One is direct MB compression of the LAD at cardiac systole, resulting in delayed arterial relaxation at diastole, reduced blood flow reserve, and decreased blood perfusion. The other is enhancement of coronary atherosclerosis causing stenosis of the LAD proximal to the MB, occurring because of endothelial injury arising from the abnormal hemodynamics provoked by retrograde blood flow up toward the left coronary ostium at cardiac systole. The magnitude of the effect of the 2 distinct mechanisms of the MB on LAD blood flow is prescribed by a common root of the MB-muscle mass volume generated by those properties. Furthermore, the anatomical properties of the MB are closely associated with the choice of treatment and therapeutic outcome in CHD patients having an MB. Thus, the anatomical properties of an MB should be considered in the diagnosis and management of CHD patients with this anomaly.
Jennifer A Tremmel - One of the best experts on this subject based on the ideXlab platform.
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off pump mini thoracotomy versus sternotomy for left anterior descending Myocardial Bridge unroofing
The Annals of Thoracic Surgery, 2020Co-Authors: Hanjay Wang, Vedant S Pargaonkar, Ian S Rogers, Camille E Hironaka, Simar S Bajaj, Chad J Abbot, Christian T Odonnell, Shari L Miller, Yasuhiro Honda, Jennifer A TremmelAbstract:Abstract Background Myocardial Bridge (MB) of the left anterior descending (LAD) coronary artery occurs in approximately 25% of the population. For patients with a symptomatic, hemodynamically significant MB who fail medical therapy, MB unroofing represents the optimal surgical management. Here, we evaluated minimally invasive MB unroofing in selected patients compared with sternotomy. Methods MB unroofing was performed in 141 adult patients via sternotomy on-pump (ST-on, n=40), sternotomy off-pump (ST-off, n=62), or mini thoracotomy off-pump (MT, n=39). Angina symptoms were assessed preoperatively and 6-months postoperatively using the Seattle Angina Questionnaire. Matching included all MT patients and 31 ST-off patients with similar MB characteristics, no previous cardiac surgery or coronary interventions, and no concomitant procedures. Results MT patients tended to have a shorter MB length than ST-on and ST-off patients (2.57 vs 2.93 vs 3.09 cm, p=0.166). ST-on patients had a longer hospital stay than ST-off and MT patients (5.0 vs 4.0 vs 3.0 days, p Conclusions We report the largest experience of off-pump minimally invasive MB unroofing, which may be safely performed in carefully selected patients, yielding dramatic improvements in angina symptomatology at 6 months after surgery.
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express Myocardial Bridge an unrecognized cause of chest pain in pulmonary arterial hypertension
Pulmonary circulation, 2020Co-Authors: Divya Rajmohan, Ingela Schnittger, Jennifer A Tremmel, Francois Haddad, Yon K Sung, Kristina Kudelko, Vinicio A De Jesus Perez, Roham T Zamanian, Edda SpiekerkoetterAbstract:Pulmonary arterial hypertension (PAH) is characterized by an increased pulmonary vascular resistance resulting in progressive right ventricular hypertrophy and failure. While dyspnea on exertion is...
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Myocardial Bridge muscle index mmi a marker of disease severity and its relationship with endothelial dysfunction and symptomatic outcome in patients with angina and a hemodynamically significant Myocardial Bridge
Journal of the American College of Cardiology, 2018Co-Authors: Vedant S Pargaonkar, Ingela Schnittger, Ian S Rogers, Shigemitsu Tanaka, Ryotaro Yamada, Takumi Kimura, Jack H Boyd, Jennifer A TremmelAbstract:Myocardial Bridge (MB) muscle index (MMI), the product of MB depth x length, is suggestive of severity of an MB. MBs are also associated with endothelial dysfunction. We studied the relationship of MMI with endothelial function, and its effect on symptomatic outcome in patients undergoing surgical
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effect of ranolazine on symptoms and quality of life in patients with angina in the absence of obstructive coronary artery disease a retrospective cohort study
Journal of the American College of Cardiology, 2018Co-Authors: Vedant S Pargaonkar, Ingela Schnittger, Jennifer A Tremmel, Abha KhandelwalAbstract:More than 20% of patients presenting to the cath lab have no significant obstructive coronary artery disease (CAD) despite having angina. Several occult coronary abnormalities, including endothelial dysfunction, microvascular dysfunction (MVD), and/or a Myocardial Bridge (MB), may explain their
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Myocardial Bridge and acute plaque rupture
Journal of investigative medicine high impact case reports, 2016Co-Authors: Leor Perl, Jennifer A Tremmel, David V Daniels, Jonathan G Schwartz, Shige Tanaka, Alan C Yeung, Ingela SchnittgerAbstract:A Myocardial Bridge (MB) is a common anatomic variant, most frequently located in the left anterior descending coronary artery, where a portion of the coronary artery is covered by myocardium. Importantly, MBs are known to result in a proximal atherosclerotic lesion. It has recently been postulated that these lesions predispose patients to acute coronary events, even in cases of otherwise low-risk patients. One such mechanism may involve acute plaque rupture. In this article, we report 2 cases of patients with MBs who presented with acute coronary syndromes despite having low cardiovascular risk. Their presentation was life-risking and both were treated urgently and studied with coronary angiographies and intravascular ultrasound. This latter modality confirmed a rupture of an atherosclerotic plaque proximal to the MB as a likely cause of the acute events. These cases, of unexplained acute coronary syndrome in low-risk patients, raise the question of alternative processes leading to the event and the role MB play as an underlying cause of ruptured plaques. In some cases, an active investigation for this entity may be warranted, due to the prognostic implications of the different therapeutic modalities, should an MB be discovered.
Kensuke Nishimiya - One of the best experts on this subject based on the ideXlab platform.
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absence of adventitial vasa vasorum formation at the coronary segment with Myocardial Bridge an optical coherence tomography study
International Journal of Cardiology, 2018Co-Authors: Kensuke Nishimiya, Yasuharu Matsumoto, Hongxin Wang, Zhonglie Piao, Kazuma Ohyama, Hironori Uzuka, Kiyotaka Hao, Ryuji Tsuburaya, Jun TakahashiAbstract:Abstract Background Myocardial Bridge (MB) is a Myocardial bundle through which coronary segment tunnels and could compress coronary arteries causing Myocardial ischemia. However, the characteristic structural findings of MB remain to be fully elucidated. Recently, we demonstrated that optical coherence tomography (OCT) enables us to visualize adventitial vasa vasorum (VV) formation in humans. In this study, we examined adventitial VV formation at the coronary segment with MB in humans using OCT. Methods We examined 15 consecutive patients with suspected angina pectoris and MB in the left anterior descending (LAD) coronary arteries but no angiographic coronary stenosis. MB was detected on coronary angiography as a segment with milking effect. We performed intracoronary OCT imaging along the entire LAD. Morphometric analysis was performed at MB and proximal/distal segments at every 1mm. Results OCT examination showed the absence of adventitial VV formation at MB in the LAD, while VV was clearly noted at both the proximal and distal reference segments. Adventitial VV area was significantly less at MB compared with the proximal or distal references. Conclusions These results with OCT imaging indicate that coronary segments with MB lack adventitial VV formation in humans, suggesting that MB could influence morphological and functional changes of the coronary artery.
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abstract 14926 absence of adventitial vasa vasorum formation at the coronary segment with Myocardial Bridge an optical coherence tomography study
Circulation, 2017Co-Authors: Kensuke Nishimiya, Yasuharu Matsumoto, Hongxin Wang, Zhonglie Piao, Kazuma Ohyama, Hironori Uzuka, Kiyotaka Hao, Ryuji Tsuburaya, Jun Takahashi, Kenta ItoAbstract:Background: Myocardial Bridge (MB) is a Myocardial bundle through which coronary segment tunnels and could compress coronary arteries causing Myocardial ischemia. However, the characteristic findin...
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abstract 17791 association of enhanced adventitial vasa vasorum formation with atherosclerotic changes in the human coronary arteries adjacent to Myocardial bridging an optical frequency domain imaging study
Circulation, 2015Co-Authors: Hongxin Wang, Kensuke Nishimiya, Yasuharu Matsumoto, Kazuma Ohyama, Hironori Uzuka, Kiyotaka Hao, Ryuji Tsuburaya, Jun Takahashi, Hirokazu Amamizu, Masayasu KomatsuAbstract:Background: Although Myocardial Bridge (MB) has been implicated as a cause of adverse cardiac events, its pathological significance remains to be fully elucidated. Recent advance in imaging with op...
Yoshikiyo Akasaka - One of the best experts on this subject based on the ideXlab platform.
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settlement of stenotic site and enhancement of risk factor load for atherosclerosis in left anterior descending coronary artery by Myocardial Bridge
Arteriosclerosis Thrombosis and Vascular Biology, 2018Co-Authors: Yuri Akishimafukasawa, Yukio Ishikawa, Yoshikiyo Akasaka, Tetuo Mikami, Toshiharu IshiiAbstract:Objective— The aim of this study was to investigate the influence of a Myocardial Bridge (MB) on atherosclerosis development in the left anterior descending artery of the normal heart and the importance of traditional risk factors (RFs). An additional objective was to determine the correlation between intimal thickening and luminal narrowing. Approach and Results— The left anterior descending artery from 150 autopsied hearts was treated with formalin perfusion fixation, and each left anterior descending artery was serially cross-sectioned. The intima–media and luminal stenosis ratios were examined using computer-assisted histomorphometry. The luminal stenosis ratio was closely correlated with the intima–media ratio ( r =0.792; P P =0.022 by a multiple comparison test), but there were no differences between the RF (+) and RF (−) groups when an MB was absent. In addition, the site of the greatest stenosis in the MB (+) RF (+) group was 2.5 cm proximal to the MB entrance. Multivariate analyses indicated that age was an independent factor for luminal stenosis ratios ≥50% and 60% ( P =0.002 and 0.029, respectively). Furthermore, the presence of an MB plus RFs was an independent factor for a luminal stenosis ratio ≥70% ( P =0.037). Conclusions— An MB enhances left anterior descending artery atherosclerosis development at a site proximal to the MB entrance, particularly in subjects who have some RFs.
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Myocardial Bridge as a structure of double edged sword for the coronary artery
Annals of Vascular Diseases, 2014Co-Authors: Toshiharu Ishii, Yukio Ishikawa, Yoshikiyo AkasakaAbstract:Myocardial Bridge (MB) is a chance anatomical structure, comprised of the Myocardial tissue, with which the coronary artery running in epicardial adipose tissue is partly covered. It is predominantly present in the left anterior descending artery (LAD) and recognizable through imaging techniques as changes in blood flow within the LAD that arises from MB contraction at cardiac systole. Such changes in blood flow influence the pathophysiology of coronary circulation and atherosclerosis development, thus generating controversy as to whether MB predisposes individual to Myocardial infarction (MI). However, recent histomorphometric studies have shown that the individual anatomic properties of MB, such as location, length and thickness, consistently play a critical role in the occurrence of MI. This review article comprehensively addresses the pathophysiological mechanisms of MI occurrence together with the benign suppressive effect of coronary atherosclerosis by MB.
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association of variance in anatomical elements of Myocardial Bridge with coronary atherosclerosis
Atherosclerosis, 2013Co-Authors: Ami Iuchi, Yukio Ishikawa, Yoshikiyo Akasaka, Yuri Akishimafukasawa, Ryuji Fukuzawa, Toshiharu IshiiAbstract:Abstract Objectives The Myocardial Bridge (MB) is an anatomical structure consisting of myocardium covering a part of the left anterior descending coronary artery (LAD). The extent and spatial distribution of atherosclerosis in the LAD with an MB is influenced by the anatomical properties of the MB. In this study, the relationship between the overall anatomical framework of the MB including the periarterial adipose tissue as well as fibrosis of the MB itself and coronary atherosclerosis was histomorphometrically examined. Methods Full-length LADs with an MB from 180 autopsied hearts were cross-sectioned at 5-mm intervals. Together with measurements of MB – length, thickness, and location, proportional decrease of the atherosclerosis ratio of LAD segments beneath MB for that of LAD segments proximal to MB was defined as the atherosclerosis suppression ratio. The area ratio of adipose tissue in the periarterial area beneath MB and area ratio of fibrosis in the MB muscle were also measured. Results The atherosclerosis suppression ratio was significantly proportional to MB length and thickness. Periarterial adipose tissue beneath MB was detected in all cases (100%), and fibrosis within MB muscle for 136 cases (75.6%). The amount of adipose tissue beneath MB and MB fibrosis did not statistically affect the atherosclerosis suppression ratio. Multivariate analysis revealed MB length and thickness were the independent factors affecting the atherosclerosis suppression ratio. Conclusions The anatomical properties of an MB, especially of its length and thickness, play decisive roles as regulators of atherosclerosis in the LAD regardless of the amount of adipose tissue around LAD and MB fibrosis.
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histopathologic profiles of coronary atherosclerosis by Myocardial Bridge underlying Myocardial infarction
Atherosclerosis, 2013Co-Authors: Yukio Ishikawa, Yoshikiyo Akasaka, Koyu Suzuki, Yuri Akishimafukasawa, Ami Iuchi, Mieko Uno, Eriko Abe, Yang Yang, Kiyoshi Mukai, Hitoshi NiinoAbstract:Abstract Objective Anatomic properties of Myocardial Bridge (MB) are sometimes responsible for Myocardial infarction (MI) through the changes in the atherosclerosis distribution in the left ascending coronary artery (LAD). The purpose of this study was to investigate histopathologic profiles of atherosclerotic lesions resulting from the MB presence in the LAD in the MI cases. Methods In 150 consecutive autopsied MI hearts either with MBs [MI(+)MB(+); n = 67] or without MBs [MI(+)MB(−); n = 83] and 100 normal hearts with MBs [MI(−)MB(+)], LADs were consecutively cross-sectioned at 5-mm intervals. The most advanced intimal lesion and unstable plaque-related lesion characteristics (UPLCs) in each section were histopathologically evaluated in conjunction with the anatomic properties of the MB, such as its thickness, length, location, and MB muscle volume burden (MMV: the total volume of MB thickness multiplied by MB length). Results The MB showed a significantly greater thickness ( P = 0.0090), length ( P = 0.0300), and MMV ( P = 0.0019) in MI(+)MB(+) than in MI(−)MB(+). Mean age of acute MI cases was significantly younger ( P = 0.0227) in MI(+)MB(+) than in MI(+)MB(−). Frequency of plaque fissure/rupture in the proximal LAD was significantly higher in acute MI cases of MI(+)MB(+) than in MI(+)MB(−). UPLCs tended to be located proximally in MI(+)MB(+) and frequent 2.0 cm or more proximal to the MB entrance in MI(+)MB(+). Conclusion In MI(+)MB(+), UPLCs tend to be located more proximally, and a plaque in the LAD proximal to the MB is prone to rupture, resulting in MI at younger age.
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anatomic properties of Myocardial Bridge predisposing to Myocardial infarction
Circulation, 2009Co-Authors: Yukio Ishikawa, Yoshikiyo Akasaka, Koyu Suzuki, Mieko Fujiwara, Takafumi Ogawa, Kazuto Yamazaki, Hitoshi Niino, Michio Tanaka, Kentaro Ogata, Shojiroh MorinagaAbstract:Background— A Myocardial Bridge (MB) that partially covers the course of the left anterior descending coronary artery (LAD) sometimes causes Myocardial ischemia, primarily because of hemodynamic deterioration, but without atherosclerosis. However, the mechanism of occurrence of Myocardial infarction (MI) as a result of an MB in patients with spontaneously developing atherosclerosis is unclear. Methods and Results— One hundred consecutive autopsied MI hearts either with MBs [MI(+)MB(+) group; n=46] or without MBs (n=54) were obtained, as were 200 normal hearts, 100 with MBs [MI(−)MB(+) group] and 100 without MBs. By microscopy on LADs that were consecutively cross-sectioned at 5-mm intervals, the extent and distribution of LAD atherosclerosis were investigated histomorphometrically in conjunction with the anatomic properties of the MB, such as its thickness, length, and location and the MB muscle index (MB thickness multiplied by MB length), according to MI and MB status. In the MI(+)MB(+) group, the MB sh...
