Anomalous aortic origin of coronary artery biomechanical modeling: Toward clinical application

Automatic 3D Segmentation and Identification of Anomalous Aortic Origin of the Coronary Arteries Combining Multi-view 2D Convolutional Neural Networks

This work aimed to automatically segment and classify the coronary arteries with either normal or anomalous origin from the aorta (AAOCA) using convolutional neural networks (CNNs), seeking to enhance and fasten clinician diagnosis. We implemented three single-view 2D Attention U-Nets with 3D view integration and trained them to automatically segment the aortic root and coronary arteries of 124 computed tomography angiographies (CTAs), with normal coronaries or AAOCA. Furthermore, we automatically classified the segmented geometries as normal or AAOCA using a decision tree model. For CTAs in the test set (n = 13), we obtained median Dice score coefficients of 0.95 and 0.84 for the aortic root and the coronary arteries, respectively. Moreover, the classification between normal and AAOCA showed excellent performance with accuracy, precision, and recall all equal to 1 in the test set. We developed a deep learning-based method to automatically segment and classify normal coronary and AAOCA. Our results represent a step towards an automatic screening and risk profiling of patients with AAOCA, based on CTA.

Management of Adults With Anomalous Aortic Origin of the Coronary Arteries: State-of-the-Art Review

As a result of increasing adoption of imaging screening, the number of adult patients with a diagnosis of anomalous aortic origin of the coronary arteries (AAOCA) has grown in recent years. Existing guidelines provide a framework for management and treatment, but patients with AAOCA present with a wide range of anomalies and symptoms that make general recommendations of limited applicability. In particular, a large spectrum of interventions can be used for treatment, and there is no consensus on the optimal approach to be used. In this paper, a multidisciplinary group of clinical and interventional cardiologists and cardiac surgeons performed a systematic review and critical evaluation of the available evidence on the interventional treatment of AAOCA in adult patients. Using a structured Delphi process, the group agreed on expert recommendations that are intended to complement existing clinical practice guidelines.

Management of Adults With Anomalous Aortic Origin of the Coronary Arteries: State-of-the-Art Review

As a result of increasing adoption of imaging screening, the number of adult patients with a diagnosis of anomalous aortic origin of the coronary arteries (AAOCA) has grown in recent years. Existing guidelines provide a framework for management and treatment, but patients with AAOCA present with a wide range of anomalies and symptoms that make general recommendations of limited applicability. In particular, a large spectrum of interventions can be used for treatment, and there is no consensus on the optimal approach to be used. In this paper, a multidisciplinary group of clinical and interventional cardiologists and cardiac surgeons performed a systematic review and critical evaluation of the available evidence on the interventional treatment of AAOCA in adult patients. Using a structured Delphi process, the group agreed on expert recommendations that are intended to complement existing clinical practice guidelines.

Lumped-parameter model as a non-invasive tool to assess coronary blood flow in AAOCA patients

Anomalous aortic origin of the coronary artery (AAOCA) is a rare disease associated with sudden cardiac death, usually related to physical effort in young people. Clinical routine tests fail to assess the ischemic risk, calling for novel diagnostic approaches. To this aim, some recent studies propose to assess the coronary blood flow (CBF) in AAOCA by computational simulations but they are limited by the use of data from literature retrieved from normal subjects. To overcome this limitation and obtain a reliable assessment of CBF, we developed a fully patient-specific lumped parameter model based on clinical imaging and in-vivo data retrieved during invasive coronary functional assessment of subjects with AAOCA. In such a way, we can estimate the CBF replicating the two hemodynamic conditions in-vivo analyzed. The model can mimic the effective coronary behavior with high accuracy and could be a valuable tool to quantify CBF in AAOCA. It represents the first step required to move toward a future clinical application with the aim of improving patient care. The study was registered at Clinicaltrial.gov with (ID: NCT05159791, date 2021-12-16).

Morphological Changes of Anomalous Coronary Arteries From the Aorta During the Cardiac Cycle Assessed by IVUS in Resting Conditions

BACKGROUND

Anomalous aortic origin of coronary artery (AAOCA) with intramural segment is associated with risk of sudden cardiac death, probably related to a compressive mechanism exerted by the aorta. However, the intramural compression occurrence and magnitude during the cardiac cycle remain unknown. We hypothesized that (1) in end diastole, the intramural segment is narrower, more elliptic, and has greater resistance than extramural segment; (2) the intramural segment experiences a further compression in systole; and (3) morphometry and its systolic changes vary within different lumen cross-sections of the intramural segment.

METHODS

Phasic changes of lumen cross-sectional coronary area, roundness (minimum/maximum lumen diameter), and hemodynamic resistance (Poiseuille law for noncircular sections) were derived from intravascular ultrasound pullbacks at rest for the ostial, distal intramural, and extramural segments. Data were obtained for 35 AAOCA (n=23 with intramural tract) after retrospective image-based gating and manual lumen segmentation. Differences between systolic and end-diastolic phases in each section, between sections of the same coronary, and between AAOCA with and without intramural tract were assessed by nonparametric statistical tests.

RESULTS

In end diastole, both the ostial and distal intramural sections were more elliptical (P<0.001) than the reference extramural section and the correspondent sections in AAOCA without intramural segment. In systole, AAOCA with intramural segment showed a flattening at the ostium (-6.76% [10.82%]; P=0.024) and a flattening (-5.36% [16.56%]; P=0.011), a narrowing (-4.62% [11.38%]; P=0.020), and a resistance increase (15.61% [30.07%]; P=0.012) at the distal intramural section. No-intramural sections did not show morphological changes during the entire cardiac cycle.

CONCLUSIONS

AAOCA with intramural segment has pathological segment-specific dynamic compression mainly in the systole under resting conditions. Studying AAOCA behavior with intravascular ultrasound during the cardiac cycle may help to evaluate and quantify the severity of the narrowing.

Patient-Specific Fluid-Structure Simulations of Anomalous Aortic Origin of Right Coronary Arteries

Objectives

Anomalous aortic origin of the right coronary artery (AAORCA) may cause ischemia and sudden death. However, the specific anatomic indications for surgery are unclear, so dobutamine-stress instantaneous wave-free ratio (iFR) is increasingly used. Meanwhile, advances in fluid–structure interaction (FSI) modeling can simulate the pulsatile hemodynamics and tissue deformation. We sought to evaluate the feasibility of simulating the resting and dobutamine-stress iFR in AAORCA using patient-specific FSI models and to visualize the mechanism of ischemia within the intramural geometry and associated lumen narrowing.

Methods

We developed 6 patient-specific FSI models of AAORCA using SimVascular software. Three-dimensional geometries were segmented from coronary computed tomography angiography. Vascular outlets were coupled to lumped-parameter networks that included dynamic compression of the coronary microvasculature and were tuned to each patient's vitals and cardiac output.

Results

All cases were interarterial, and 5 of 6 had an intramural course. Measured iFRs ranged from 0.95 to 0.98 at rest and 0.80 to 0.95 under dobutamine stress. After we tuned the distal coronary resistances to achieve a stress flow rate triple that at rest, the simulations adequately matched the measured iFRs (r = 0.85, root-mean-square error = 0.04). The intramural lumen remained narrowed with simulated stress and resulted in lower iFRs without needing external compression from the pulmonary root.

Conclusions

Patient-specific FSI modeling of AAORCA is a promising, noninvasive method to assess the iFR reduction caused by intramural geometries and inform surgical intervention. However, the models’ sensitivity to distal coronary resistance suggests that quantitative stress-perfusion imaging may augment virtual and invasive iFR studies.

Anomalous Aortic Origin of the Coronary Arteries - State of the Art Management and Surgical Techniques

Anomalous aortic origin of a coronary artery (AAOCA) can be associated with myocardial ischemia and sudden cardiac arrest. We describe and compare the management and surgical techniques for patients with AAOCA. Patients presenting to the Coronary Artery Anomalies Program are evaluated and managed following a standardized approach. Our approach and data were compared to other single-center and multi-institutional data and results. Patients with AAOCA present as an incidental finding approximately 50% of the time. Advanced axial imaging is essential to define the anatomic characteristics of this lesion. Preoperative and postoperative assessment of myocardial perfusion with provocative testing is feasible and contributes to risk stratification. The surgical techniques for AAOCA repair include coronary unroofing, transection and reimplantation, and neo-ostium creation, among others. In general, surgical repair of AAOCA can mitigate the risk of ischemia with low mortality. The specific morbidities and complications of each different technique should be considered during the surgical planning. Surgical repair of AAOCA can mitigate the risk of ischemia with a low associated mortality but with clinically relevant morbidities. Long-term follow-up is necessary to accurately balance the risks of repaired and unrepaired AAOCA.