RESUMEN
BACKGROUND: Myocardial bridging is a cardiac anomaly where a segment of epicardial coronary arteries runs through the myocardium and can rarely cause MI. Takotsubo syndrome is a stress-induced cardiomyopathy that can mimic MI. Catecholamine surge during stress can contribute to Takotsubo syndrome, but whether this surge can trigger an inconspicuous myocardial bridging to manifest symptomatically remains unclear, and alternately, whether a myocardial bridge might cause worsening of Takotsubo syndrome is also a matter that needs further research. CASE PRESENTATION: We report the case of a patient who initially presented with features of acute exacerbation of bronchiectasis and subsequently developed symptoms and ECG features suggestive of acute myocardial infarction. Echocardiography revealed features of takotsubo syndrome, and complete myocardial bridging was revealed via coronary angiography. The patient was managed conservatively with pharmacological treatment, and after a few days, echocardiographic features were reversed. As such, the diagnosis shifted toward Takotsubo syndrome with myocardial stunning due to co-existent myocardial bridging. CONCLUSION: We report a rare case of a patient with acute bronchiectasis exacerbation with features suggestive of acute myocardial infarction who had findings of Takotsubo syndrome and complete myocardial bridging. In the beginning, it was difficult to determine whether the symptoms arose due to acute MI resulting from myocardial bridging or were solely due to takotsubo syndrome because of stress from bronchiectasis. Although myocardial bridging is often overlooked as an etiology for acute MI, this case highlights the importance of expanding the differential diagnosis to myocardial bridging in the work-up for the cause of acute MI and how Takotsubo syndrome can mimic acute MI and pose a diagnostic challenge.
Asunto(s)
Angiografía Coronaria , Puente Miocárdico , Infarto del Miocardio , Valor Predictivo de las Pruebas , Cardiomiopatía de Takotsubo , Humanos , Cardiomiopatía de Takotsubo/fisiopatología , Cardiomiopatía de Takotsubo/diagnóstico , Cardiomiopatía de Takotsubo/diagnóstico por imagen , Cardiomiopatía de Takotsubo/terapia , Cardiomiopatía de Takotsubo/etiología , Infarto del Miocardio/diagnóstico , Infarto del Miocardio/complicaciones , Infarto del Miocardio/fisiopatología , Infarto del Miocardio/etiología , Diagnóstico Diferencial , Puente Miocárdico/complicaciones , Puente Miocárdico/diagnóstico por imagen , Puente Miocárdico/diagnóstico , Puente Miocárdico/fisiopatología , Aturdimiento Miocárdico/diagnóstico , Aturdimiento Miocárdico/etiología , Aturdimiento Miocárdico/fisiopatología , Femenino , Resultado del Tratamiento , Electrocardiografía , Anciano , MasculinoRESUMEN
BACKGROUND: Clinical events such as angina pectoris, acute coronary syndrome, and sudden death caused by myocardial bridge (MB) have attracted increasing attention. It is still a challenge to diagnose whether MB can cause the symptoms of patients with MB. For most MB patients, medication remains the primary treatment. CASE PRESENTATION: This article reports a case of chest pain in a patient with MB in the middle segment of the left anterior descending artery (LADm) with moderate stenosis in the proximal segment (LADp). Through functional assessment, we found that neither MB nor fixed stenosis had sufficient effect on coronary blood flow to cause myocardial ischemia, but their synergistic effect resulted in myocardial ischemia. Finally, a stent was implanted in LADp and good clinical results were achieved. CONCLUSIONS: For symptomatic patients with MB combined with fixed stenosis, functional evaluation may be necessary, which has significant guiding significance for treatment strategy selection. For asymptomatic patients, early detection of myocardial ischemia may also improve the prognosis of patients.
Asunto(s)
Estenosis Coronaria , Puente Miocárdico , Humanos , Estenosis Coronaria/fisiopatología , Estenosis Coronaria/diagnóstico por imagen , Estenosis Coronaria/terapia , Estenosis Coronaria/etiología , Puente Miocárdico/complicaciones , Puente Miocárdico/fisiopatología , Puente Miocárdico/diagnóstico por imagen , Resultado del Tratamiento , Masculino , Stents , Angiografía Coronaria , Persona de Mediana Edad , Isquemia Miocárdica/fisiopatología , Isquemia Miocárdica/etiología , Isquemia Miocárdica/terapia , Isquemia Miocárdica/diagnóstico por imagen , Intervención Coronaria Percutánea/instrumentación , Anciano , Índice de Severidad de la EnfermedadRESUMEN
OBJECTIVE: To compare the performance between CT-derived fractional flow reserve (CT-FFR) and ΔCT-FFR measurements in patients with deep myocardial bridging (MB) along the left anterior descending artery, and explore the potential predictors of discordance. METHODS: 175 patients with deep MB who underwent coronary computed tomography angiography (CCTA) and CT-FFR assessment were included. Clinical, anatomical and atherosclerotic variables were compared between patients with concordant and discordant CT-FFR and ΔCT-FFR. RESULTS: 30.9 % patients were discordantly classified, in which 94.4 % patients were classified as CT-FFR+/â³CT-FFR-. The discordant group showed significantly higher upstream stenosis degree, distance from MB to the aorta, â³CT-FFR (P 0.007, 0.009 and 0.002, respectively), and lower CT-FFR (P < 0.001). In multivariate analysis, upstream stenosis degree (P 0.023, OR 1.628, 95 % CI: 1.068-2.481) and distance from MB to the aorta (P 0.001, OR 1.04, 95 % CI: 1.016-1.064) were independent predictors for discordance between CT-FFR and ΔCT-FFR. CONCLUSION: The discordance between CT-FFR and ΔCT-FFR measurements underscores the challenges in clinical decision-making, necessitating tailored approaches for MB evaluation.
Asunto(s)
Angiografía por Tomografía Computarizada , Angiografía Coronaria , Reserva del Flujo Fraccional Miocárdico , Puente Miocárdico , Humanos , Reserva del Flujo Fraccional Miocárdico/fisiología , Masculino , Femenino , Persona de Mediana Edad , Angiografía por Tomografía Computarizada/métodos , Puente Miocárdico/diagnóstico por imagen , Puente Miocárdico/fisiopatología , Puente Miocárdico/complicaciones , Angiografía Coronaria/métodos , Estudios Retrospectivos , Anciano , Valor Predictivo de las PruebasRESUMEN
BACKGROUND: Myocardial bridging (MB) is accompanied by the dynamic extravascular compression of epicardial coronary arteries, leading to intracoronary hemodynamic disturbance with abnormal coronary flow profiles. We aimed to evaluate the prognostic implications of resistive reserve ratio (RRR), a composite measure of flow and pressure parameters that represents the vasodilatory capacity of the coronary arteries, in patients with angina with nonobstructive coronary artery disease (ANOCA) and MB, in comparison with coronary flow reserve (CFR). METHODS AND RESULTS: In this retrospective cohort study, we included patients with ANOCA who underwent coronary reactivity testing, where MB was identified by transient constriction in coronary artery segments between systole and diastole. Abnormal CFR and RRR were defined as <2.5 and <2.62, respectively. Major adverse cardiac events, including cardiovascular death, stroke, myocardial infarction, heart failure, and late revascularization, served as outcomes. Among 1251 patients with ANOCA, 191 (15.3%) had MB. The prevalence of abnormal CFR or RRR was not significantly different between patients with and without MB (P=0.144 and P=0.398, respectively). Over a median follow-up time of 6.9 years, abnormal RRR predicted major adverse cardiac events in patients with MB (hazard ratio [HR], 4.38 [95% CI, 1.71-11.21]; P=0.002) and without MB (HR, 1.91 [95% CI, 1.38-2.64]; P<0.001). Abnormal CFR predicted major adverse cardiac events in patients without MB (HR, 2.15 [95% CI, 1.54-3.00]; P<0.001), whereas it was not predictive of major adverse cardiac events in patients with MB (HR, 2.29 [95% CI, 0.93-5.65]; P=0.073). CONCLUSIONS: In patients with ANOCA and MB, impaired RRR was superior to impaired CFR in distinguishing patients at a higher risk of future adverse events, suggesting that RRR may serve as a risk stratification tool in patients with MB and ANOCA.
Asunto(s)
Enfermedad de la Arteria Coronaria , Puente Miocárdico , Humanos , Femenino , Masculino , Estudios Retrospectivos , Persona de Mediana Edad , Enfermedad de la Arteria Coronaria/fisiopatología , Enfermedad de la Arteria Coronaria/diagnóstico , Pronóstico , Anciano , Puente Miocárdico/fisiopatología , Puente Miocárdico/complicaciones , Puente Miocárdico/diagnóstico , Resistencia Vascular/fisiología , Reserva del Flujo Fraccional Miocárdico/fisiología , Circulación Coronaria/fisiología , Vasos Coronarios/fisiopatología , Vasos Coronarios/diagnóstico por imagen , Factores de Riesgo , Valor Predictivo de las Pruebas , Angiografía CoronariaRESUMEN
PURPOSE OF REVIEW: This review investigates the relationship between myocardial bridges (MBs), intimal thickening in coronary arteries, and Atherosclerotic cardiovascular disease. It focuses on the role of mechanical forces, such as circumferential strain, in arterial wall remodeling and aims to clarify how MBs affect coronary artery pathology. REVIEW FINDINGS: MBs have been identified as influential in modulating coronary artery intimal thickness, demonstrating a protective effect against thickening within the MB segment and an increase in thickness proximal to the MB. This is attributed to changes in mechanical stress and hemodynamics. Research involving arterial hypertension models and vein graft disease has underscored the importance of circumferential strain in vascular remodeling and intimal hyperplasia. Understanding the complex dynamics between MBs, mechanical strain, and vascular remodeling is crucial for advancing our knowledge of coronary artery disease mechanisms. This could lead to improved management strategies for cardiovascular diseases, highlighting the need for further research into MB-related vascular changes.
Asunto(s)
Puente Miocárdico , Humanos , Puente Miocárdico/fisiopatología , Puente Miocárdico/complicaciones , Vasos Coronarios/fisiopatología , Vasos Coronarios/patología , Enfermedad de la Arteria Coronaria/fisiopatología , Túnica Íntima/patología , Animales , Aterosclerosis/fisiopatología , Remodelación Vascular/fisiología , Estrés MecánicoAsunto(s)
Angiografía por Tomografía Computarizada , Angiografía Coronaria , Puente Miocárdico , Valor Predictivo de las Pruebas , Humanos , Puente Miocárdico/diagnóstico por imagen , Puente Miocárdico/fisiopatología , Puente Miocárdico/complicaciones , Vasos Coronarios/diagnóstico por imagen , Masculino , Interpretación de Imagen Radiográfica Asistida por Computador , Persona de Mediana Edad , Femenino , Reproducibilidad de los ResultadosRESUMEN
Myocardial bridging (MB) is a congenital coronary anomaly in which a segment of the epicardial coronary artery traverses through the myocardium for a portion of its length. The muscle overlying the artery is termed a myocardial bridge, and the intramyocardial segment is referred to as a tunneled artery. MB can occur in any coronary artery, although is most commonly seen in the left anterior descending artery. Although traditionally considered benign in nature, increasing attention is being given to specific subsets of MB associated with ischemic symptomatology. The advent of contemporary functional and anatomic imaging modalities, both invasive and noninvasive, have dramatically improved our understanding of dynamic pathophysiology associated with MBs. This review provides a contemporary overview of epidemiology, pathobiology, diagnosis, functional assessment, and management of MBs.
Asunto(s)
Angiografía Coronaria/métodos , Circulación Coronaria/fisiología , Vasos Coronarios/diagnóstico por imagen , Manejo de la Enfermedad , Puente Miocárdico/diagnóstico , Angiografía por Tomografía Computarizada/métodos , Vasos Coronarios/fisiopatología , Humanos , Puente Miocárdico/fisiopatología , Puente Miocárdico/terapia , Ultrasonografía IntervencionalRESUMEN
Background Functional assessment of myocardial bridging (MB) remains clinically challenging because of the dynamic nature of the extravascular coronary compression with a certain degree of intraluminal coronary reduction. The aim of our study was to assess performance and diagnostic value of diastolic-fractional flow reserve (d-FFR) during dobutamine provocation versus conventional-FFR during adenosine provocation with exercise-induced myocardial ischemia as reference. Methods and Results This prospective study includes 60 symptomatic patients (45 men, mean age 57±9 years) with MB on the left anterior descending artery and systolic compression ≥50% diameter stenosis. Patients were evaluated by exercise stress-echocardiography test, and both conventional-FFR and d-FFR in the distal segment of left anterior descending artery during intravenous infusion of adenosine (140 µg/kg per minute) and dobutamine (10-50 µg/kg per minute), separately. Exercise-stress-echocardiography test was positive for myocardial ischemia in 19/60 patients (32%). Conventional-FFR during adenosine and peak dobutamine had similar values (0.84±0.04 versus 0.84±0.06, P=0.852), but d-FFR during peak dobutamine was significantly lower than d-FFR during adenosine (0.76±0.08 versus 0.79±0.08, P=0.018). Diastolic-FFR during peak dobutamine was significantly lower in the exercise-stress-echocardiography test -positive group compared with the exercise- stress-echocardiography test -negative group (0.70±0.07 versus 0.79±0.06, P<0.001), but not during adenosine (0.79±0.07 versus 0.78±0.09, P=0.613). Among physiological indices, d-FFR during peak dobutamine was the only independent predictor of functionally significant MB (odds ratio, 0.870; 95% CI, 0.767-0.986, P=0.03). Receiver-operating characteristics curve analysis identifies the optimal d-FFR during peak dobutamine cut-off ≤0.76 (area under curve, 0.927; 95% CI, 0.833-1.000; P<0.001) with a sensitivity, specificity, and positive and negative predictive value of 95%, 95%, 90%, and 98%, respectively, for identifying MB associated with stress-induced ischemia. Conclusions Diastolic-FFR, but not conventional-FFR, during inotropic stimulation with high-dose dobutamine, in comparison to vasodilatation with adenosine, provides more reliable functional significance of MB in relation to stress-induced myocardial ischemia.
Asunto(s)
Adenosina/administración & dosificación , Cardiotónicos/administración & dosificación , Ecocardiografía de Estrés , Reserva del Flujo Fraccional Miocárdico , Puente Miocárdico/diagnóstico por imagen , Isquemia Miocárdica/diagnóstico por imagen , Vasodilatadores/administración & dosificación , Adulto , Anciano , Diástole , Dobutamina/administración & dosificación , Prueba de Esfuerzo , Estudios de Factibilidad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Puente Miocárdico/complicaciones , Puente Miocárdico/fisiopatología , Isquemia Miocárdica/etiología , Isquemia Miocárdica/fisiopatología , Valor Predictivo de las Pruebas , Estudios Prospectivos , Reproducibilidad de los ResultadosRESUMEN
Successful recanalization of coronary chronic total occlusion (CTO) can induce subsequent positive vascular remodeling. Although myocardial bridge (MB) is known to alter endothelial function and wall shear stress, the impact of MB on late lumen enlargement in the distal segment is unclear. A total of 59 patients who underwent successful percutaneous coronary intervention (PCI) for CTO in the left anterior descending artery (LAD) under intravascular ultrasound (IVUS) guidance and follow-up angiography at 8-12 months were included. Gray-scale IVUS images were analyzed and MB was detected. Lumen diameter (LD) at distal reference at post-PCI was quantitatively compared with corresponding LD at follow-up coronary angiography to assess late lumen enlargement. MB on IVUS was detected in 17 patients (29%). The length from LAD ostium to the entry of CTO was shorter (11.7 ± 13.9 vs. 22.8 ± 13.4 mm, p = 0.006) and LD at distal reference at post-PCI was smaller (1.65 ± 0.54 vs. 1.97 ± 0.56 mm, p = 0.049) in patients with MB than those without. At the mean follow-up of 10.4 ± 2.4 months, LD at distal reference was significantly increased by 25% from baseline to follow-up in the overall population (1.88 ± 0.57 vs. 2.21 ± 0.41 mm, p < 0.001), with a greater increase in patients with MB compared to those without (46 ± 31% vs. 17 ± 29%, p < 0.001). Multivariable analysis indicated MB as an independent predictor of late lumen enlargement. In patients with MB on IVUS, CTO was located in more proximal segment of LAD than those without. Late lumen enlargement at follow-up was greater in patients with MB compared to the counterpart.
Asunto(s)
Oclusión Coronaria/terapia , Vasos Coronarios/fisiopatología , Puente Miocárdico/fisiopatología , Intervención Coronaria Percutánea , Remodelación Vascular , Anciano , Enfermedad Crónica , Angiografía Coronaria , Oclusión Coronaria/diagnóstico por imagen , Oclusión Coronaria/fisiopatología , Vasos Coronarios/diagnóstico por imagen , Femenino , Humanos , Masculino , Persona de Mediana Edad , Puente Miocárdico/diagnóstico por imagen , Intervención Coronaria Percutánea/efectos adversos , Estudios Retrospectivos , Factores de Tiempo , Resultado del Tratamiento , Ultrasonografía IntervencionalRESUMEN
RATIONALE: Coronary chest pain is usually ischemic in etiology and has various electrocardiographic presentations. Lately, it has been recognized that myocardial bridging (MB) with severe externally mechanical compression of an epicardial coronary artery during systole may result in myocardial ischemia. Such a phenomenon can be associated with chronic angina pectoris, acute coronary syndromes (ACS), coronary spasm, ventricular septal rupture, arrhythmias, exercise-induced atrioventricular conduction blocks, transient ventricular dysfunction, and sudden death. PATIENT CONCERNS: We report the case of a 58-year-old woman presenting with recurrent episodes of constrictive chest pain during exercise within the last 2 weeks. Except for obesity, general and cardiovascular clinical examination on admission were normal. DIAGNOSES: The resting 12 lead electrocardiogram (ECG) revealed changes typically for Wellens syndrome. High-sensitive cardiac troponin I was normal. We established the diagnosis of low-risk non-ST-segment elevation acute coronary syndrome with a Global Registry of Acute Coronary Events risk score of 92 points. INTERVENTIONS: The patient underwent coronary angiography, who showed subocclusive dynamic obstruction of the left anterior descending artery due to MB. OUTCOMES: The patient was managed conservatively. Her hospital course was uneventful and she was discharged on pharmacological therapy (clopidogrel, bisoprolol, amlodipine, atorvastatin, and metformin) with well-controlled symptoms on followup. LESSONS: MB is an unusual cause of myocardial ischemia. Wellens syndrome is an unusual presentation of ACS. We present herein a rare case of Wellens syndrome caused by MB. This case highlights the importance of subtle and frequently overseen ECG findings when assessing patients with chest pain and second, the importance of considering nonatherosclerotic causes for ACS.
Asunto(s)
Síndrome Coronario Agudo/diagnóstico , Oclusión Coronaria/diagnóstico por imagen , Puente Miocárdico/diagnóstico por imagen , Dolor en el Pecho/etiología , Angiografía Coronaria , Electrocardiografía , Femenino , Humanos , Persona de Mediana Edad , Puente Miocárdico/fisiopatología , SíndromeRESUMEN
BACKGROUND: Myocardial bridge (MB) often an inoffensive condition that goes in one or more of the coronary arteries through the heart muscle instead of lying on its surface. MBs sometimes leads to myocardial ischemic symptoms such as chest pain, even an occurrence of myocardial infarction. However, reports of severe and recurrent cardiac adverse events related to the MBs are rare. CASE PRESENTATION: A 44-year-old male patient who suffered from a four-hour crushing chest pain ten years ago, was diagnosed as acute anterior ST-elevation myocardial infarction (STEMI). The initial findings of coronary angiography (CAG) showed MB was located in the middle part of the left anterior descending coronary artery (LAD). The patient was managed medically. Another re-attack of similar previous chest pain characteristics occured just after 3 days of discharge. Supra-arterial myotomy and CABG were the next adopted management. Postoperative progression was uneventful. However, 32 months after surgical treatment, the patient experienced an abrupt onset of chest pain accompanied by loss of consciousness. The ECG showed ventricular fibrillation (VF). After electrical cardioversion, an immediate CAG followed by CTA was performed which excluded thrombus or acute occlusion in the native coronary artery and an occlusion was observed at the end of the left internal mammary artery. An implantable cardioverter-defibrillator (ICD) was successfully performed for prevention of malignant arrhythmia. During ten years of follow-up, no complications have been identified. CONCLUSIONS: Although MB is mostly benign, it may lead to significant cardiovascular consequences. Supra-arterial myotomy is an appropriate treatment option for this patient who failed to optimal medical therapy. Furthermore, ICD implantation must be considered in order to prevent malignant ventricular arrhythmia caused by continuous spasm resulting in ischemia. Further investigations are required to confirm the clinical effectiveness of these procedures.
Asunto(s)
Infarto de la Pared Anterior del Miocardio/etiología , Vasoespasmo Coronario/etiología , Puente Miocárdico/complicaciones , Infarto del Miocardio con Elevación del ST/etiología , Fibrilación Ventricular/etiología , Adulto , Infarto de la Pared Anterior del Miocardio/diagnóstico por imagen , Infarto de la Pared Anterior del Miocardio/fisiopatología , Infarto de la Pared Anterior del Miocardio/terapia , Puente de Arteria Coronaria , Vasoespasmo Coronario/diagnóstico por imagen , Vasoespasmo Coronario/fisiopatología , Vasoespasmo Coronario/terapia , Desfibriladores Implantables , Cardioversión Eléctrica/instrumentación , Humanos , Masculino , Puente Miocárdico/diagnóstico por imagen , Puente Miocárdico/fisiopatología , Puente Miocárdico/terapia , Miotomía , Recurrencia , Infarto del Miocardio con Elevación del ST/diagnóstico por imagen , Infarto del Miocardio con Elevación del ST/fisiopatología , Infarto del Miocardio con Elevación del ST/terapia , Resultado del Tratamiento , Fibrilación Ventricular/diagnóstico , Fibrilación Ventricular/fisiopatología , Fibrilación Ventricular/terapiaAsunto(s)
Angiografía por Tomografía Computarizada , Angiografía Coronaria , Vasoespasmo Coronario/diagnóstico por imagen , Vasos Coronarios/diagnóstico por imagen , Tomografía Computarizada Multidetector , Puente Miocárdico/diagnóstico por imagen , Vasoconstricción , Acetilcolina/administración & dosificación , Anciano , Vasoespasmo Coronario/fisiopatología , Vasos Coronarios/fisiopatología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Puente Miocárdico/fisiopatología , Valor Predictivo de las Pruebas , Vasoconstrictores/administración & dosificaciónAsunto(s)
Arteria Coronaria Izquierda Anómala/diagnóstico por imagen , Angiografía por Tomografía Computarizada , Angiografía Coronaria , Puente Miocárdico/diagnóstico por imagen , Isquemia Miocárdica/diagnóstico por imagen , Arteria Coronaria Izquierda Anómala/complicaciones , Arteria Coronaria Izquierda Anómala/fisiopatología , Arteria Coronaria Izquierda Anómala/terapia , Tratamiento Conservador , Femenino , Humanos , Persona de Mediana Edad , Puente Miocárdico/complicaciones , Puente Miocárdico/fisiopatología , Puente Miocárdico/terapia , Isquemia Miocárdica/etiología , Isquemia Miocárdica/fisiopatología , Isquemia Miocárdica/terapia , Valor Predictivo de las PruebasRESUMEN
Myocardial bridging (MB) is linked to angina and myocardial ischemia and may lead to sudden cardiac death in patients with hypertrophic cardiomyopathy (HCM). However, it remains unclear how MB affect the coronary blood flow in HCM patients. The aim of this study was to assess the effects of MB on coronary hemodynamics in HCM patients. Fifteen patients with MB (7 HCM and 8 non-HCM controls) in their left anterior descending (LAD) coronary artery were chosen. Transient computational fluid dynamics (CFD) simulations were conducted in anatomically realistic models of diseased (with MB) and virtually healthy (without MB) LAD from these patients, reconstructed from biplane angiograms. Our CFD simulation results demonstrated that dynamic compression of MB led to diastolic flow disturbances and could significantly reduce the coronary flow in HCM patients as compared with non-HCM group (P < 0.01). The pressure drop coefficient was remarkably higher (P < 0.05) in HCM patients. The flow rate change is strongly correlated with both upstream Reynolds number and MB compression ratio, while the MB length has less impact on coronary flow. The hemodynamic results and clinical outcomes revealed that HCM patients with an MB compression ratio higher than 65% required a surgical intervention. In conclusion, the transient MB compression can significantly alter the diastolic flow pattern and wall shear stress distribution in HCM patients. HCM patients with severe MB may need a surgical intervention.NEW & NOTEWORTHY In this study, the hemodynamic significance of myocardial bridging (MB) in patients with hypertrophic cardiomyopathy (HCM) was investigated to provide valuable information for surgical decision-making. Our results illustrated that the transient MB compression led to complex flow patterns, which can significantly alter the diastolic flow and wall shear stress distribution. The hemodynamic results and clinical outcomes demonstrated that patients with HCM and an MB compression ratio higher than 65% required a surgical intervention.
Asunto(s)
Cardiomiopatía Hipertrófica/fisiopatología , Hemodinámica , Modelos Cardiovasculares , Puente Miocárdico/fisiopatología , Modelación Específica para el Paciente , Adolescente , Adulto , Anciano , Cardiomiopatía Hipertrófica/complicaciones , Cardiomiopatía Hipertrófica/patología , Circulación Coronaria , Femenino , Humanos , Masculino , Persona de Mediana Edad , Puente Miocárdico/complicaciones , Puente Miocárdico/patologíaRESUMEN
The force-frequency relationship (FFR) is an important regulatory mechanism that increases the force-generating capacity as well as the contraction and relaxation kinetics in human cardiac muscle as the heart rate increases. In human heart failure, the normally positive FFR often becomes flat, or even negative. The rate of cross-bridge cycling, which has been reported to affect cardiac output, could be potentially dysregulated and contribute to blunted or negative FFR in heart failure. We recently developed and herein use a novel method for measuring the rate of tension redevelopment. This method allows us to obtain an index of the rate of cross-bridge cycling in intact contracting cardiac trabeculae at physiological temperature and assess physiological properties of cardiac muscles while preserving posttranslational modifications representative of those that occur in vivo. We observed that trabeculae from failing human hearts indeed exhibit an impaired FFR and a reduced speed of relaxation kinetics. However, stimulation frequencies in the lower spectrum did not majorly affect cross-bridge cycling kinetics in nonfailing and failing trabeculae when assessed at maximal activation. Trabeculae from failing human hearts had slightly slower cross-bridge kinetics at 3 Hz as well as reduced capacity to generate force upon K+ contracture at this frequency. We conclude that cross-bridge kinetics at maximal activation in the prevailing in vivo heart rates are not majorly impacted by frequency and are not majorly impacted by disease.NEW & NOTEWORTHY In this study, we confirm that cardiac relaxation kinetics are impaired in filing human myocardium and that cross-bridge cycling rate at resting heart rates does not contribute to this impaired relaxation. At high heart rates, failing myocardium cross-bridge rates are slower than in nonfailing myocardium.
Asunto(s)
Insuficiencia Cardíaca/fisiopatología , Frecuencia Cardíaca , Puente Miocárdico/fisiopatología , Adulto , Anciano , Gasto Cardíaco , Femenino , Humanos , Técnicas In Vitro , Cinética , Masculino , Persona de Mediana Edad , Contracción Miocárdica , Disfunción Ventricular Izquierda/fisiopatología , Adulto JovenRESUMEN
OBJECTIVES: There is an association between long and thick myocardial bridging (MB), haemodynamic perturbations and increased risk of myocardial infarction. This study aims to investigate the alteration in coronary haemodynamics with increasing the length of MB. METHODS: Angiography and intravascular ultrasound were performed in 10 patients with varying length of MB in the left anterior descending (LAD) artery. In silico models of MB were developed based on the reconstructed three-dimensional model of the LAD. The entire LAD was divided into 3 segments, proximal (pre-bridge), bridge and distal (post-bridge). Transient computational fluid dynamics simulations were performed to derive distribution of blood residence time and wall shear stress (WSS) over entire vessel including proximal, bridge and distal segments. RESULTS: With increasing the length of MB, a decreasing trend was observed in the WSS over proximal segment whereas an increasing trend was found in the WSS over bridge segment. When patients were divided into 2 groups based on the average length of MB in the whole cohort (Laveâ¯=â¯23.92â¯mm), patients with bridges longer than Lave had smaller WSS and higher residence time in the proximal segment compared to those with bridges shorter than Lave (0.59 ± 0.31 vs 0.21 ± 0.14â¯Pa and 0.0021 ± 0.0015 vs 0.0045 ± 0.0021â¯s). In contrast, patients with bridges longer than Lave had greater WSS in the bridge segment compared to those with bridges shorter than Lave (1.37 ± 1.66 vs 2.53 ± 3.14â¯Pa). No significant difference was found in the distal WSS of patients with short and long bridges. CONCLUSION: Our findings revealed a direct relationship between the length of MB and haemodynamic perturbations in the proximal segment such that the increased length of MB is associated with decreased WSS and increased residence time.
Asunto(s)
Vasos Coronarios/diagnóstico por imagen , Cardiopatías Congénitas/fisiopatología , Hemodinámica , Puente Miocárdico/fisiopatología , Adulto , Anciano , Algoritmos , Arterias , Simulación por Computador , Angiografía Coronaria , Vasos Coronarios/anatomía & histología , Vasos Coronarios/fisiopatología , Femenino , Cardiopatías Congénitas/complicaciones , Humanos , Hidrodinámica , Procesamiento de Imagen Asistido por Computador , Imagenología Tridimensional , Masculino , Persona de Mediana Edad , Modelos Cardiovasculares , Movimiento (Física) , Puente Miocárdico/complicaciones , Resistencia al Corte , Estrés Mecánico , UltrasonografíaRESUMEN
OBJECTIVES: Myocardial bridging (MB) can cause myocardial ischemia, myocardial infarction, or even sudden cardiac death. We aimed to evaluate the left ventricular function in patients with MB of the left anterior descending coronary artery (LAD) using longitudinal strain (LS) measured by two-dimensional speckle tracking echocardiography. METHODS: We enrolled 46 subjects with MB in the LAD diagnosed by coronary angiography. Patients were categorized into two groups according to the severity of tunneled artery stenosis: <50% as group I (23 patients) and ≥50% as group II (23 patients). Twenty-five gender- and age-matched subjects without MB confirmed by coronary angiography or with normal results on treadmill exercise test were included as controls. Two-dimensional strain software was applied to measure the territories systolic average peak LS of the LAD coronary artery (LAD-TPLS), right coronary artery (RCA-TPLS), and left circumflex coronary artery (LCX-TPLS) and to measure the global systolic peak LS of left ventricle (LV-GPLS). RESULTS: The ratio of mitral peak early (E) and late (A) filling velocity (E/A) and the average mitral annular velocity (e') were lower, and the mitral E/e' ratio was higher in group II than in group I and controls (P < 0.05). LV-GPLS and LAD-TPLS were significantly less negative in group II than in group I and controls (LV-GPLS: -19.77 ± 1.60% vs -21.10 ± 1.91% and -21.76 ± 1.23%; LAD-TPLS: -19.24 ± 2.22% vs -22.00 ± 2.22% and -22.74 ± 1.82%, P < 0.001). The systolic compression severity of the tunneled artery was significantly correlated with LAD-TPLS (r = -0.56, P < 0.001), but less strongly correlated with LV-GPLS (r = -0.40, P < 0.05). The area under the curves of LAD-TPLS was larger than that of LV-GPLS; a cutoff value for LAD-TPLS of -21.68% had 91.3% sensitivity and 73.9% specificity for detection of ≥50% of the tunneled artery stenosis. CONCLUSIONS: In patients with ≥50% systolic narrowing of the tunneled artery, left ventricular systolic function and diastolic function were impaired, and the LAD-TPLS is an excellent predictor of ≥50% systolic narrowing of the tunneled artery in patients with MB of the LAD.
Asunto(s)
Vasos Coronarios/fisiopatología , Ecocardiografía/métodos , Puente Miocárdico/complicaciones , Puente Miocárdico/fisiopatología , Disfunción Ventricular Izquierda/complicaciones , Disfunción Ventricular Izquierda/diagnóstico por imagen , Disfunción Ventricular Izquierda/fisiopatología , Femenino , Ventrículos Cardíacos/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Sensibilidad y EspecificidadRESUMEN
OBJECTIVES: This study aims to examine the alteration in coronary haemodynamics with increasing the severity of vessel compression caused by myocardial bridging (MB). METHODS: Angiography and intravascular ultrasound were performed in 10 patients with MB with varying severities of systolic compression in the left anterior descending (LAD) artery. Computer models of MB were developed and transient computational fluid dynamics simulations were performed to derive distribution of blood residence time and shear stress. RESULTS: With increasing the severity of bridge compression, a decreasing trend was observed in the shear stress over proximal segment whereas an increasing trend was found in the shear stress over bridge segment. When patients were divided into 2 groups based on the average systolic vessel compression in the whole cohort (%CRave = 27.38), patients with bridges with major systolic compression (>%CRave) had smaller shear stress and higher residence time in the proximal segment compared to those with bridges with minor systolic compression (<%CRave) (0.37 ± 0.23 vs 0.69 ± 0.29 Pa and 0.0037 ± 0.0069 vs 0.022 ± 0.0094 s). In contrast, patients with bridges with major systolic compression had greater shear stress in the bridge segment compared to those with bridges with minor systolic compression (2.49 ± 2.06 vs 1.13 ± 0.89 Pa). No significant difference was found in the distal shear stress of patients with bridges with major and minor systolic compression. CONCLUSION: Our findings revealed a direct relationship between the severity of systolic compression of MB and haemodynamic perturbations in the proximal segment such that the increased systolic vessel compression was associated with decreased shear stress and increased blood residence time.
Asunto(s)
Hemodinámica/fisiología , Puente Miocárdico/fisiopatología , Presión Sanguínea , Angiografía Coronaria , Diástole/fisiología , Femenino , Humanos , Hidrodinámica , Masculino , Persona de Mediana Edad , Puente Miocárdico/diagnóstico por imagen , Miocardio/patología , Sístole/fisiología , Factores de TiempoAsunto(s)
Angiografía por Tomografía Computarizada , Angiografía Coronaria/métodos , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Vasos Coronarios/diagnóstico por imagen , Reserva del Flujo Fraccional Miocárdico , Interpretación de Imagen Asistida por Computador , Aprendizaje Automático , Puente Miocárdico/diagnóstico por imagen , Placa Aterosclerótica , Anciano , Enfermedad de la Arteria Coronaria/etiología , Enfermedad de la Arteria Coronaria/fisiopatología , Vasos Coronarios/fisiopatología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Puente Miocárdico/complicaciones , Puente Miocárdico/fisiopatología , Valor Predictivo de las Pruebas , Pronóstico , Estudios Retrospectivos , Factores de Riesgo , Factores de TiempoRESUMEN
Myocardial bridging (MB) is associated with endothelial dysfunction in patients with angina and non-obstructive coronary artery disease. This study aims to determine if there is a link between abnormal blood flow patterns and endothelial dysfunction in patients with MB. Ten patients with MB in their left anterior descending (LAD) artery were selected, 5 of whom had endothelial dysfunction and 5 had no endothelial dysfunction based on their response to acetylcholine. Similarly, 10 patients without MB in their LAD, 5 of whom had endothelial dysfunction and 5 of whom had no endothelial dysfunction, were studied as a control group. Transient computational fluid dynamics simulations were performed to derive wall shear stress (WSS) over the entire vessel including proximal, middle and distal segments. Patients with MB and endothelial dysfunction had lower WSS in the proximal LAD and greater WSS in the mid-LAD than patients with MB but without endothelial dysfunction. When comparing patients with endothelial dysfunction, those with MB had significantly lower shear stress in the proximal LAD (0.32⯱â¯0.14â¯Pa (with MB) vs 0.71⯱â¯0.38â¯Pa (without MB), pâ¯=â¯0.01) and greater shear stress in the mid-LAD (2.81⯱â¯1.20â¯Pa (with MB) vs 1.66⯱â¯0.31â¯Pa (without MB), pâ¯=â¯0.014) than patients without MB. Our findings demonstrated that the presence of MB significantly contributes to low WSS and endothelial dysfunction relationship.