Managing Stenotic Septal Perforator Branches

Graph neural networks for automatic extraction and labeling of the coronary artery tree in CT angiography

Purpose

Automatic comprehensive reporting of coronary artery disease (CAD) requires anatomical localization of the coronary artery pathologies. To address this, we propose a fully automatic method for extraction and anatomical labeling of the coronary artery tree using deep learning.

Approach

We include coronary CT angiography (CCTA) scans of 104 patients from two hospitals. Reference annotations of coronary artery tree centerlines and labels of coronary artery segments were assigned to 10 segment classes following the American Heart Association guidelines. Our automatic method first extracts the coronary artery tree from CCTA, automatically placing a large number of seed points and simultaneous tracking of vessel-like structures from these points. Thereafter, the extracted tree is refined to retain coronary arteries only, which are subsequently labeled with a multi-resolution ensemble of graph convolutional neural networks that combine geometrical and image intensity information from adjacent segments.

Results

The method is evaluated on its ability to extract the coronary tree and to label its segments, by comparing the automatically derived and the reference labels. A separate assessment of tree extraction yielded an F 1 score of 0.85. Evaluation of our combined method leads to an average F 1 score of 0.74.

Conclusions

The results demonstrate that our method enables fully automatic extraction and anatomical labeling of coronary artery trees from CCTA scans. Therefore, it has the potential to facilitate detailed automatic reporting of CAD.

Vasospasm in the First Septal Perforator Branch and Late High-Grade Atrioventricular Block Following Successful Primary Percutaneous Coronary Intervention for the Proximal Left Anterior Descending Coronary Artery: A Case Report

We present a case of a high-degree advanced atrioventricular block (AVB), which occurred 24 hours after successful primary percutaneous coronary intervention (PCI) in the proximal left anterior descending coronary artery (LAD), the culprit of ST-segment elevation myocardial infarction (STEMI). The methylergometrine provocation test for coronary vasospasms, which was performed on the eighth hospital day, revealed transient total occlusion of the first septal perforator branch. After prescribing a calcium channel blocker to the patient, AVB did not recur for three years, as confirmed using an implantable loop recorder (ILR). In this patient, delayed high-grade AVB following primary PCI in the proximal LAD might be caused by the spasm of the first septal perforator branch. Documented cases of spasms in this branch are rare.

Complete Atrioventricular Block and Permanent Pacemaker Implantation Following Percutaneous Coronary Intervention to Left Anterior Descending Artery Chronic Total Occlusion

A 72-year-old male patient, with first degree atrioventricular block and LBBB on his baseline ECG, developed persistent complete atrioventricular block after recanalization of a chronic total occlusion of his left anterior descending artery (LAD) and ultimately underwent permanent pacemaker implantation. Occlusion of the second septal branch, probably supplying the right branch of the His bundle is speculated to have led to this complication. During elective intervention to the LAD territory in patients with prior conduction abnormalities on the ECG, care should be taken to preserve normal blood flow to the septal perforators. When a deterioration in septal perfusion occurs restoration of flow by wiring and balloon dilatation should be considered.

Rescue Percutaneous Coronary Intervention for a Lethal "Jailed" Septal Perforator Branch to Resolve Delayed Complete Atrioventricular Block

Delayed complete atrioventricular (AV) block associated with an occluded septal perforator branch (SPB) is an uncommon complication after performing percutaneous coronary intervention (PCI) for the left anterior descending coronary artery (LAD). Here we report the case of a 74-year-old man who underwent elective PCI for proximal LAD complicated with occlusion of the first major SPB and developed a complete AV block 78 hours after PCI was performed. The patient received a temporary transvenous pacemaker via the jugular vein and successfully underwent balloon angioplasty of the lethal "jailed" SPB, resulting in recovery from the complete AV block. Permanent pacemaker implantation was avoided. Our findings indicate the importance of postprocedural monitoring and consideration of rescue PCI for an occluded SPB in cases of complicated AV conduction disturbances.