Novel Percutaneous Approach for Deployment of 3D Printed Coronary Stenosis Implants in Swine Models of Ischemic Heart Disease

Minimally invasive methods for creating models of focal coronary narrowing in large animals are challenging. Rapid prototyping using three-dimensionally (3D) printed coronary implants can be employed to percutaneously create a focal coronary stenosis. However, reliable delivery of the implants can be difficult without the use of ancillary equipment. We describe the use of a mother-and-child coronary guide catheter for stabilization of the implant and for effective delivery of the 3D printed implant to any desired location along the length of the coronary vessel. The focal coronary narrowing was confirmed under coronary cineangiography and the functional significance of the coronary stenosis was assessed using gadolinium-enhanced first-pass cardiac perfusion MRI. We showed that reliable delivery of 3D printed coronary implants in swine models (n = 11) of ischemic heart disease can be achieved through repurposing mother-and-child coronary guide catheters. Our technique simplifies the percutaneous delivery of coronary implants to create closed-chest swine models of focal coronary artery stenosis and can be performed expeditiously, with a low procedural failure rate.

Visit-to-visit Blood Pressure Variability and Arterial Stiffness: Which Came First: The Chicken or the Egg?

Earlier studies have shown that visit-to-visit blood pressure (BP) variability (VVV) served as a significant independent risk factor of stroke, specifically, in the high-risk elderly of cardiovascular disease (CVD). Although the mechanism is not clearly understood, arterial remodeling such as carotid artery, coronary artery and large aortic artery would be a strong moderator in the relationship between VVV and CVD incidence. Recent studies have provided evidence that VVV predicted the progression of arterial stiffness. While the class of antihypertensive agents is suggested to be an important determinant of VVV, long-acting calcium channel blockers use (CCBs) is associated with the reduction of VVV, and thus, is suggested to decrease the arterial stiffness. Specifically, the relationship between VVV and coronary arterial remodeling has never been reviewed until now. This article summarizes the recent literature on these topics. In the elderly hypertensives, strict BP control using CCBs could play a pivotal role in suppressing arterial stiffening via VVV reduction.

Circulating Anti-Sorting Nexins 16 Antibodies as an Emerging Biomarker of Coronary Artery Disease in Patients with Obstructive Sleep Apnea

Biomarkers are not available for monitoring the onset and progression of coronary artery disease (CAD) in patients with obstructive sleep apnea (OSA), a major risk factor for arteriosclerotic cardiovascular diseases. This study aimed to test for correlation between circulating anti-Sorting Nexins 16 antibody (SNX16-Ab) levels, CAD history and clinical parameters of patients with OSA. Sixty-four healthy donors, 82 adults with OSA, and 96 with acute coronary syndrome (ACS) were studied. Serum samples were collected at diagnostic polysomnography in the OSA group or at the disease onset in the ACS group. Serum SNX16-Ab levels were measured by amplified luminescence proximity homogeneous assay (AlphaLISA), and correlation between SNX16-Ab levels and clinical parameters was analyzed. SNX16-Ab levels and apnea-hypopnea index (AHI) were weakly correlated. Additionally, logistic regression analyses of OSA group identified that elevated SNX16-Ab level associated with the history of CAD. Circulating SNX16-Ab could increase during CAD pathogenesis in patients with OSA. Further prospective studies are required to prove the predictive potential of SNX16-Ab level in CAD onset of patients with OSA.

Traumatic Right Coronary Artery Dissection as a Cause of Inferior Wall ST-Elevation Myocardial Infarction

Blunt cardiac injury, causing coronary artery dissection in the absence of other forms of injury to the heart or lungs is a rare occurrence. Here we present a case of a 41-year-old male who presented with right coronary artery (RCA) dissection after blunt chest trauma. The patient initially presented with chest pain and was diagnosed with an inferior wall myocardial infarction (MI). He then developed a complete heart block and bedside echocardiogram showed right ventricular akinesis. Immediate coronary angiography showed RCA dissection, and TIMI 3 flow was established after the placement of four drug-eluting stents. Blunt trauma-induced RCA dissection is associated with high mortality which needs immediate treatment. Hence through this case report, we would like to stress the importance of having a high index of suspicion for this condition in patients with a blunt chest injury.

Acute Myocardial Infarction Caused by Distal Embolization From a Proximal Ruptured Plaque

Generally, in acute myocardial infarction, the plaque rupture site is around the occluded site. In this case, coronary angioscopy effectively detected a rupture at a nonstenotic lesion, and the consequent thrombotic occlusion may lead to acute myocardial infarction apart from rupture. Aspirated plaques contained atheromatous materials, cholesterol crystals, and fibrin. (Level of Difficulty: Intermediate.)

Uric acid is not associated with diabetic nephropathy and other complications in type 1 diabetes

BACKGROUND

To examine the association between plasma uric acid (UA) and the presence of diabetic complications including diabetic nephropathy and cardiovascular risk factors in patients with type 1 diabetes.

METHODS

This study, which is cross-sectional in design, included 676 Caucasian type 1 diabetes patients from the Steno Diabetes Center Copenhagen. Participants with UA within the three lowest sex-specific quartiles were compared with participants with levels in the highest quartile. Unadjusted and adjusted linear regression analyses were applied. Adjustment included sex, age, diabetes duration, body mass index, high-density lipoprotein cholesterol, smoking, haemoglobin A1c, 24-h pulse pressure, urinary albumin excretion rate (UAER), estimated glomerular filtration rate (eGFR) and treatment with renin-angiotensin-aldosterone system blockers.

RESULTS

Of the 676 patients, 372 (55%) were male, mean ± SD age was 55 ± 13 years and eGFR was 82 ± 26 mL/min/1.73 m2. The median UA was 0.30 (interquartile range 0.23-0.37) mmol/L. UA in the upper sex-specific quartile was associated with lower eGFR, higher UAER and carotid-femoral pulse wave velocity and lower 24 h and daytime diastolic blood pressure (BP) in unadjusted analyses (P < 0.001). Moreover, UA in the upper sex-specific quartile was associated with higher nighttime systolic BP and the presence of cardiovascular disease in unadjusted analyses (P ≤ 0.01), but significance was lost after adjustment (P ≥ 0.17). UA was higher across the retinopathy groups [nil (n = 142), simplex (n = 277), proliferative (n = 229) and blind (n = 19)] in unadjusted analyses (P < 0.0001), but not after adjustment (P = 0.12). Patients with an accelerated decline in eGFR (≥3 mL/min/year) had significantly higher UA at baseline (P = 0.006) compared with slow decliners (<3 mL/min/year), but significance was lost after adjustment (P = 0.10).

CONCLUSIONS

In type 1 diabetes patients, higher UA was associated with lower kidney function and other diabetic complications. The association between higher UA and lower eGFR and lower diastolic BP was independent of traditional risk factors.

An automatic diagnostic system of coronary artery lesions in Kawasaki disease using intravascular optical coherence tomography imaging

Intravascular optical coherence tomography (IV-OCT) is a light-based imaging modality with high resolution, which employs near-infrared light to provide tomographic intracoronary images. Morbidity caused by coronary heart disease is a substantial cause of acute coronary syndrome and sudden cardiac death. The most common intracoronay complications caused by coronary artery disease are intimal hyperplasia, calcification, fibrosis, neovascularization and macrophage accumulation, which require efficient prevention strategies. OCT can provide discriminative information of the intracoronary tissues, which can be used to train a robust fully automatic tissue characterization model based on deep learning. In this study, we aimed to design a diagnostic model of coronary artery lesions. Particularly, we trained a random forest using convolutional neural network features to distinguish between normal and diseased arterial wall structure. Then, based on the arterial wall structure, fully convolutional network is designed to extract the tissue layers in normal cases, and pathological tissues regardless of lesion type in pathological cases. Then, the type of the lesions can be characterized with high precision using our previous model. The results demonstrate the robustness of the model with the approximate overall accuracy up to 90%.

Aspirin Dose and Treatment Outcomes in Kawasaki Disease: A Historical Control Study in Japan

Aspirin has been used as a concomitant drug in the treatment of Kawasaki disease (KD). In recent years, there has been discussion concerning whether high-dose aspirin is appropriate for treatment in the acute phase of KD. We retrospectively investigated the incidence of coronary artery abnormalities (CAAs) and the antipyretic effect of 30 to 50 mg/kg/day aspirin, the minimum and the maximum approved doses in Japan. This was a single-center, non-randomized, retrospective, historical cohort study. Patients were routinely treated with 50 mg/kg/day aspirin (50-mg Group) between 2007 and April 2014, and with 30 mg/kg/day aspirin (30-mg Group) between May 2014 and 2016. All patients were given initial and, if necessary, subsequent intravenous immunoglobulin (IVIG) 2.0 g/kg. The primary endpoint was incidence of CAAs defined as a CA diameter with a Z score ≥2.5 at treatment week 4. The secondary endpoint was incidence of further treatment. Incidences were compared using inverse probability weighting analysis adjusting for age, sex, and risk scores. In 587 patients, there was no significant difference in incidence of CAAs (odds ratio in 30-mg Group 0.769, 95% confidence interval (CI): 0.537-1.101, p = 0.151). Risk of further treatment after the first IVIG in the 30-mg Group was significantly higher than that in the 50-mg Group (odds ratio 1.379, 95% CI: 1.051-1.811, p = 0.021). Although this study has some limitations, the findings suggest that aspirin 50 mg/kg/day may have no significant effect on improving incidence of CAAs compared with 30 mg/kg/day but may have a lower rate of further treatment.

The incidence of arrhythmias during exercise stress tests among children with Kawasaki disease: A single-center case series

OBJECTIVE

Based on 2017 guidelines, participation in competitive sports with prior history of Kawasaki Disease (KD) requires those with coronary artery aneurysms (CAA) z score ≥ 5 to undergo evaluation for evidence of inducible ischemia or arrhythmias. The use of exercise stress testing (EST) to evaluate arrhythmias among KD patients has never been reported. This retrospective single-center case series study sought to describe the presence of inducible arrhythmias during EST in KD patients with or without CAA.

METHODS

Single-center retrospective review of medical records of patients diagnosed with KD between 1989-2015 at Texas Children's Hospital, Houston, Texas who underwent EST were included.

RESULTS

Among 1007 patients diagnosed with KD, 95 (9%) underwent 165 ESTs at a median time of 9.6 years (IQR 5.8-11.3 years) from diagnosis. Of these 95 patients, 37 had normal coronaries, 21 dilated (z score 2 to <2.5), 10 small (5 >z ≥2.5), 12 medium (10>z ≥ 5 absolute dimension <8 mm), 10 large (z ≥10 or absolute dimension ≥8 mm), 5 severe (myocardial infarct or bypass graft). Supraventricular tachycardia was not seen. Ventricular arrhythmias during EST were uncommon and seen only among patients with CAA z ≥5. Ventricular tachycardia occurred in a single patient with a large CAA, known VT and ICD. High-grade ventricular ectopy was seen in one patient who had severe CAA and underwent bypass grafting.

CONCLUSIONS

Arrhythmias on EST were noted only among patients with CAA z ≥5. The current guidelines are a reasonable approach to increasing healthy activity among KD patients. Clarification regarding which inducible arrhythmias meet criteria for activity restriction may be helpful to guide sport participation.

Potential Prognostic, Diagnostic and Therapeutic Markers for In-stent Reocclusion in Advanced Age Patients After Coronary Stenting

BACKGROUND

Oxidative stress and inflammatory response played important roles in advanced atherosclerosis. We tried to confirm clinical diagnostic significance of the assessments of oxidative stress and inflammatory response status with in-stent reocclusion in 283 advanced age patients (80～90 years) after coronary stenting.

METHODS

We analyzed levels of circulating superoxide dismutase 3 (SOD3), nitric oxide (NO), endothelial nitric oxide synthase (eNOS), malondialdehyde (MDA), acrolein（ACR）, and paraoxonase-1 （PON-1）in advanced age patients with in-stent restenosis and reocclusion after coronary stenting.

RESULTS

Levels of SOD3, eNOS, NO and PON-1 were lowered (P<0.001) and levels of MDA and ACR were increased (P<0.001).

CONCLUSION

The assessments of the biomarkers of oxidative stress and inflammatory response (levels of MDA and ACR) and anti-oxidant biomarkers (levels of eNOS, NO, SOD3 and PON-1) could be considered as potential prognostic and diagnostic indicators of in-stent reocclusion in advanced age patients after coronary stenting.

Carotid artery blood velocity decreases in patients with coronary slow flow: A manifestation of systemic arteriosclerosis

OBJECTIVES

Coronary slow flow phenomenon (CSFP) could be a manifestation of systemic arteriosclerosis, as coronary and carotid arteries have similar intimal thickening. However, as an initial cause of arteriosclerosis, hemodynamic changes in carotid arteries have rarely been studied.

METHODS

Twenty patients with angiography-proven CSFP and 39 patients with normal coronary flow (NCF) were enrolled. TIMI frame counts (CTFC) were investigated. Carotid intima-media thickness (CIMT), peak systolic velocity (PSV), and end-diastolic velocity (EDV) were measured by ultrasonography, and shear rate (SR) and resistance index (RI) were calculated.

RESULTS

The results showed that PSV, EDV, SR, and RI were significantly lower in patients with CSFP (p＜0.01), but CIMT was significantly increased (P ＜ 0.01). PSV, EDV, SR, and RI were negatively correlated with CTFC, while CIMT was positively correlated with CTFC. Logistic regression analysis revealed that PSV (OR = 0.95, P < 0.01) could be an independent protective factor against CSFP, but CIMT (OR = 1.10, P ＜ 0.05) and male gender (OR = 9.89, P ＜ 0.01) could be risk factors for CSFP.

CONCLUSIONS

The slow flow phenomenon was observed in both coronary and carotid arteries, which could be a characteristic manifestation of systemic arteriosclerosis in CSFP; the lower wall shear stress may be the underlying mechanism. Carotid ultrasound could be applied in the noninvasive diagnosis of CSFP in the future.

A case of coronary-pulmonary artery fistula with coronary artery aneurysm detected for Kawasaki disease remote phase

Follow-up echocardiography showed two coronary-pulmonary artery fistulae and a coronary artery aneurysm in a 12-year-old boy who had been diagnosed with Kawasaki disease without persistent coronary artery lesion at the acute phase when he was 6-months-old. Left coronary arteriogram confirmed the fistulae and the 4.3 × 6.3 mm aneurysm. Results show that the fistula is associated with Kawasaki disease.

Large Aneurysm of the Left Main Coronary Artery: A Case Report

Left main coronary artery aneurysms are very rare and are incidentally encountered in about 0.1% of patients undergoing angiography. Atherosclerosis represents the main cause of this aneurysm in adult patients. Here, the author presents a case of a 58-year-old female with a history of hypertension and diabetes who had a Canadian Cardiovascular Society Grade II–III angina for the past 6 months. Selective coronary angiography revealed a large aneurysm involving the left main coronary artery (measuring 2 cm × 3 cm) with extensive coronary calcifications, ectatic proximal left circumflex followed by 80% stenotic lesion with normal left anterior descending and right coronary artery. The patient was managed with coronary artery bypass grafting along with ligation of the aneurysm. At the 3-month follow-up, the patient was asymptomatic. Therefore, distal coronary artery bypass surgery represents one of the therapeutic options and was safe and effective in our case.

A Comparison of Coronary Artery Stenosis Estimates Made by Forensic Pathologists and Medical Students

Previous studies suggest cardiovascular pathologists are less accurate than noncardiovascular pathologists (e.g., clinical pathologists) in estimating the degree of coronary artery stenosis. To further investigate the effect of training on accurate estimation of coronary artery stenosis, we designed a study to compare the accuracy of estimates made by forensic pathologists versus medical students. Six forensic pathologists and twelve medical students each independently examined 24 images of coronary artery cross sections and gave an estimate of the degree of stenosis. When comparing all 24 images, the forensic pathologists had a median difference between the estimated percentage of stenosis and actual percentage of stenosis of -12.380 and the medical students had a median difference of -16.50 (p-value of 0.08542). In estimating the percentage of stenosis, training in forensic pathology does not guarantee significantly improved accuracy compared with medical students. Our study showed no consistent statistically significant difference between estimates given by forensic pathologists and by medical students.

BKCa compensates impaired coronary vasoreactivity through RhoA/ROCK pathway in hind-limb unweighted rats

Previous studies have demonstrated cardiac and vascular remodeling induced by microgravity exposure. Yet, as the most important branch of vasculatures circulating the heart, the coronary artery has been seldomly studied about its adaptations under microgravity conditions. Large-conductance Ca²⁺-activated potassium channel (BK_Ca) and the Ras homolog family member A (RhoA)/Rho kinase (ROCK) pathway play key roles in control of vascular tone and mediation of microgravity-induced vascular adjustments. Therefore, we investigated the adaptation of coronary vasoreactivity to simulated microgravity and the role of BK_Ca and the RhoA/ROCK pathway in it. Four-week-old hind-limb unweighted (HU) rats were adopted to simulate effects of microgravity. Right coronary artery (RCA) constriction was measured by isometric force recording. The activity and expression of BK_Ca and the RhoA/ROCK pathway were examined by Western blot, patch-clamp recordings, and immunoprecipitation. We found HU significantly decreased RCA vasoconstriction to KCl, serotonin, and U-46619, but increased protein expression and current densities of BK_Ca, inhibition of which by iberiotoxin (IBTX) further decreased RCA vasoconstriction (P < 0.05). Expression of RhoA and ROCK as well as active RhoA and phosphorylation of myosin light chain (MLC) at Ser¹⁹ and MLC phosphatase target-1 at Thr⁶⁹⁶ were significantly increased by HU, and ROCK inhibitor Y-27632 exerted greater suppressing effect on HU RCA vasoconstriction than that of control (P < 0.05). BK_Ca opener NS1619 increased HU RCA vasoconstriction, which was blocked by both RhoA and ROCK inhibitor, similar to the effect of IBTX. These results indicate that HU impairs coronary vasoconstriction but enhances BK_Ca activity acting as a protective mechanism avoiding excessive decrease of coronary vasoreactivity through activation of the RhoA/ROCK pathway.-Wu, Y., Yue, Z., Wang, Q., Lv, Q., Liu, H., Bai, Y., Li, S., Xie, M., Bao, J., Ma, J., Zhu, X., Wang, Z. BK_Ca compensates impaired coronary vasoreactivity through RhoA/ROCK pathway in hind-limb unweighted rats.

Intact and Isolated Human Cadaveric Coronary Artery Perfusion Models to Facilitate Research and Education Regarding Coronary Anatomy and Pathology

Cadaveric tissue-perfusion models are well established in the fields of structural heart and peripheral vascular disease; however, less consideration has been given toward coronary artery disease despite comparable prevalence and morbidity. Two tissue-perfusion models were developed to address this need. The first, an intact heart model, allows simulation of percutaneous coronary interventional procedures. The second focuses upon isolated arteries, allowing quantification of simulated procedures. Both models were applied for clinical training and for investigations into medical device behavior. The manner of preparation facilitates access to clinically relevant disease, thus providing a platform to further research on coronary artery disease.

Increased inward rectifier K+ current of coronary artery smooth muscle cells in spontaneously hypertensive rats; partial compensation of the attenuated endothelium-dependent relaxation via Ca2+ -activated K+ channels

Endothelium-dependent vasorelaxation is partly mediated by small-conductance (SK3) and intermediate-conductance Ca²⁺ -activated K⁺ channels (SK4) in the endothelium that results in endothelium-dependent hyperpolarization (EDH). Apart from the electrical propagation through myoendothelial gap junctions, the K⁺ released from the endothelium facilitates EDH by increasing inward rectifier K⁺ channel (Kir) conductance in smooth muscle cells. The EDH-dependent relaxation of coronary artery (CA) and Kir current in smooth muscle cells (CASMCs) of hypertensive animals are poorly understood despite the critical role of coronary flow in the hypertrophic heart. In spontaneously hypertensive (SHR) and control (WKY) rats, we found attenuation of the CA relaxation by activators of SK3 and SK4 (NS309 and 1-EBIO) in SHR. In isolated CASMCs, whole-cell patch-clamp study revealed larger I_Kir in SHR than WKY, whereas the myocytes of skeletal and cerebral arteries showed smaller I_Kir in SHR than WKY. While the treatment with I_Kir inhibitor (0.1 mmol/L Ba²⁺ ) alone did not affect the WKY-CA, the SHR-CA showed significant contractile response, suggesting relaxing influence of the higher I_{K ir} in the CASMCs of SHR. Furthermore, the attenuation of NS309-induced relaxation of CA by the combined treatment with 0.1 mmol/L Ba²⁺ was more prominent in SHR than WKY. Our study firstly shows a distinct increase of I_{K ir} in the CASMCs of SHR, which could partly compensate for the attenuated relaxation via endothelial SK3 and SK4.

Intrapericardial Ectopic Goiter: A Very Unusual Presentation

Mediastinal ectopic goiter is a thyroid tumor that lies entirely below a plane extending from the superior surface of the first thoracic vertebra to the suprasternal notch, and commonly lies in the vicinity of the thymus. Intrapericardial ectopic goiter is extremely rare. We present an extremely rare case of a 63-year-old woman with an intrapericardial ectopic goiter and review the pertinent literature.

Coronary aspiration thrombectomy after using intravenous recombinant tissue plasminogen activator in a patient with acute ischemic stroke: a case report

The complication of myocardial infarction after using intravenous recombinant tissue plasminogen activator (rt-PA) in patients with acute ischemic stroke is rare. Several of these cases have been reported in the first 3 hours after infusion of rt-PA. There is controversy on how to manage treatment of the coronary artery, such as intravenous anticoagulants and antiplatelets, at the same time. We introduce a new strategy for treatment of a patient who had ischemic stroke and developed myocardial infarction after intravenous rt-PA therapy. Our case had coronary and cerebral intervention in combination with low-dose intravenous rt-PA. He was successfully treated for coronary occlusion with aspiration thrombectomy.

Mathematical modelling of the restenosis process after stent implantation

The stenting procedure has evolved to become a highly successful technique for the clinical treatment of advanced atherosclerotic lesions in arteries. However, the development of in-stent restenosis remains a key problem. In this work, a novel two-dimensional continuum mathematical model is proposed to describe the complex restenosis process following the insertion of a stent into a coronary artery. The biological species considered to play a key role in restenosis development are growth factors, matrix metalloproteinases, extracellular matrix, smooth muscle cells and endothelial cells. Diffusion-reaction equations are used for modelling the mass balance between species in the arterial wall. Experimental data from the literature have been used in order to estimate model parameters. Moreover, a sensitivity analysis has been performed to study the impact of varying the parameters of the model on the evolution of the biological species. The results demonstrate that this computational model qualitatively captures the key characteristics of the lesion growth and the healing process within an artery subjected to non-physiological mechanical forces. Our results suggest that the arterial wall response is driven by the damage area, smooth muscle cell proliferation and the collagen turnover among other factors.

In Silico Tissue Engineering: A Coupled Agent-Based Finite Element Approach

Over the past two decades, the increase in prevalence of cardiovascular diseases and the limited availability of autologous blood vessels and saphenous vein grafts have motivated the development of tissue-engineered vascular grafts (TEVGs). However, compliance mismatch and poor mechanical properties of the TEVGs remain as two major issues that need to be addressed. Researchers have investigated the role of various culture conditions and mechanical conditioning in deposition and orientation of collagen fibers, which are the key structural components in the vascular wall; however, the intrinsic complexity of mechanobiological interactions demands implementing new engineering approaches that allow researchers to investigate various scenarios more efficiently. In this study, we utilized a coupled agent-based finite element analysis (AB-FEA) modeling approach to study the effect of various loading modes (uniaxial, biaxial, and equibiaxial), boundary conditions, stretch magnitudes, and growth factor concentrations on growth and remodeling of smooth muscle cell-populated TEVGs, with specific focus on collagen deposition and orientation. Our simulations (12 weeks of culture) showed that biaxial cyclic loading (and not uniaxial or equibiaxial) leads to alignment of collagen fibers in the physiological directions. Moreover, axial boundary conditions of the TEVG act as determinants of fiber orientations. Decreasing the serum concentration, from 10% to 5% or 1%, significantly decreased the growth and remodeling speed, but only affected the fiber orientation in the 1% serum case. In conclusion, in silico tissue engineering has the potential to evolve the future of tissue engineering, as it will allow researchers to conceptualize various interactions and investigate numerous scenarios with great speed. In this study, we were able to predict the orientation of collagen fibers in TEVGs using a coupled AB-FEA model in less than 8 h. Impact Statement Tissue-engineered vascular grafts (TEVGs) hold potential to replace the current gold standard of vascular grafting, saphenous vein grafts. However, developing TEVGs that mimic the mechanical performance of the native tissue remains a challenging task. We developed a computational model of the grafts' remodeling processes and studied the effects of various loading mechanisms and culture conditions on collagen fiber orientation, which is a key factor in mechanical performance of the grafts. We were able to predict the fiber orientations accurately and show that biaxial loading and axial boundary conditions are important factors in collagen fiber organization.

Utility of local atrial electrogram pattern for predicting left main coronary artery anatomical distance during mapping in the left pulmonary sinus of valsalva

BACKGROUND

Ablation of right ventricular outflow tract (RVOT) ventricular arrhythmia (VA) within the left pulmonary sinus of Valsalva (LPSV) may increase the risk of left main coronary artery (LMCA) injury.

PURPOSE

To delineate the anatomical characteristics between LMCA and LPSV and their association with atrial potential (AP) mapping in LPSV.

METHODS

A total of 104 consecutive patients with RVOT-VA undergoing cardiac-gated computed tomography coronary angiography (CTCA) after ablation were retrospectively analyzed.

RESULTS

The LMCA-LPSV anatomic relationship was classified into three types based on the CTCA measurements. Types 1 and 2 had a shorter LMCA-LPSV distance than that of type 3 (P < .001). The left atrial appendage (LAA)-LMCA distance and LAA-LPSV distance were associated with the incidence of AP in LPSV (odds ratio [OR] = 3.43, 95% confidence interval [CI]: 1.86-6.34, P < .001; OR = 1.196, 95% CI: 1.09-1.31, P < .001, respectively). Furthermore, the LMCA-LPSV distance showed a linear correlation with the LAA-LPSV distance (r²  = 0.93, P < .001). According to receiver operating characteristic (ROC) analysis, a LMCA-LPSV distance <5.4 mm could predict the possibility of AP during LPSV mapping (sensitivity 83%, specificity 81%, and area under the ROC curve 0.86).

CONCLUSIONS

The presence of AP in the LPSV may be useful to predict a short distance from the LPSV to the LMCA and to identify patients at higher risk of LMCA injury. This information may contribute to efficient and safe ablation in this area but should be confirmed in future studies.

Vascular Calcification: The Evolving Relationship of Vascular Calcification to Major Acute Coronary Events

Calcification in a coronary artery is accepted as definite evidence of coronary atherosclerosis. The extent and density of calcification, as combined in the Agatston score, is associated with the risk of a patient experiencing a major acute coronary event. Atherosclerosis occurs because damaged endothelial cells allow low-density lipoprotein cholesterol (LDLc) to leak into subintimal tissue. Proteoglycans in subendothelial collagen have a high affinity for LDLc, retaining the lipoprotein cholesterol complex. As the endothelial damage is repaired, the subintimal LDLc is trapped. Retained LDLc induces an inflammatory response in the overlying endothelium, causing the endothelium to express chemotactic peptides. Chemotactic peptides attract circulating monocytes, which follow the concentration gradient, enter the tissue, and become tissue macrophages to phagocytize and digest the irritating LDLc in the atheroma. In the process of digesting LDLc, enzymes in the macrophages oxidize the LDLc complex. Oxidized LDL is toxic to macrophages; when present in sufficient quantity, it may cause death of macrophages, contributing to inflammation in the atheroma. In a necrotic inflammatory lesion, the regulatory mechanisms that control tissue concentrations of calcium and phosphorus are lost, allowing the solubility product of calcium phosphate to be exceeded, resulting in the formation of microscopic calcium-phosphate crystals. With ongoing inflammation, additional calcium-phosphate crystals are formed, which may aggregate. When these aggregated calcium phosphate crystals exceed 1 mm, the lesions become visible on clinical CT as coronary calcifications. Serial gated CT scans of the heart have demonstrated that once formed, CT-visible calcifications do not decrease significantly in size but may increase.