Distal-vessel fractional flow reserve by computed tomography to monitor epicardial coronary artery disease

AIMS

Coronary computed tomography angiography (CTA) and fractional flow reserve by computed tomography (FFR-CT) are increasingly utilized to characterize coronary artery disease (CAD). We evaluated the feasibility of distal-vessel FFR-CT as an integrated measure of epicardial CAD that can be followed serially, assessed the CTA parameters that correlate with distal-vessel FFR-CT, and determined the combination of clinical and CTA parameters that best predict distal-vessel FFR-CT and distal-vessel FFR-CT changes.

METHODS AND RESULTS

Patients (n = 71) who underwent serial CTA scans at ≥2 years interval (median = 5.2 years) over a 14-year period were included in this retrospective study. Coronary arteries were analysed blindly using artificial intelligence-enabled quantitative coronary CTA. Two investigators jointly determined the anatomic location and corresponding distal-vessel FFR-CT values at CT1 and CT2. A total of 45.3% had no significant change, 27.8% an improvement, and 26.9% a worsening in distal-vessel FFR-CT at CT2. Stepwise multiple logistic regression analysis identified a four-parameter model consisting of stenosis diameter ratio, lumen volume, low density plaque volume, and age, that best predicted distal-vessel FFR-CT ≤ 0.80 with an area under the curve (AUC) = 0.820 at CT1 and AUC = 0.799 at CT2. Improvement of distal-vessel FFR-CT was captured by a decrease in high-risk plaque and increases in lumen volume and remodelling index (AUC = 0.865), whereas increases in stenosis diameter ratio, medium density calcified plaque volume, and total cholesterol presaged worsening of distal-vessel FFR-CT (AUC = 0.707).

CONCLUSION

Distal-vessel FFR-CT permits the integrative assessment of epicardial atherosclerotic plaque burden in a vessel-specific manner and can be followed serially to determine changes in global CAD.

Performance and Integration of Smartphone Wireless ECG Monitoring into the Enterprise Electronic Health Record: First Clinical Experience

Introduction:

Patient initiated, remote cardiac monitoring has proved to be a significant advance in the diagnosis and management of arrhythmias. Further improvements in ease of use and access to results will further improve health outcomes and cost-effectiveness. Here we describe a proof-of-concept evaluation to assess the feasibility of successfully implementing a cloud-based management system using KardiaPro (KP) for remote electrocardiogram (ECG) monitoring to interface into EPIC, an enterprise electronic health record (EHR) system.

Methods:

The KP management system was embedded using hypertext markup language (HTML) code directly into the EHR. Encrypted credentials and patient data were bundled with an application programming interface key allowing linkage of remote monitoring from patients’ smartphones. During the time of implementation, a total of 322 patients and 32 179 ECGs were recorded.

Results:

The KP-EHR interface provided full functionality, allowing detection, interpretation and documentation of atrial fibrillation (AF), flutter events, ventricular tachycardia, and complete heart block. Our study focused on KP’s detection of AF, and 16.7% of tracings were classified as probable AF with only 2.3% of tracings not analyzed by the KP algorithm because of tracings that were too noisy or truncated. Enhanced management was facilitated with clinical information immediately accessible. Blinded physician ECG review validated the KP proprietary algorithm interpretation and ECGs.

Conclusions:

Direct integration of KP into EHR was successful and practical. It allows for historical, point of care and immediate retrieval of remote ambulatory monitoring data and documentation into the electronic health record. KP EHR integration warrants further study as it has the potential to improve cost-effectiveness and clinical diagnostic value, leading to improvements in delivery of patient care.

Left Main Coronary Artery Thrombus Diagnosed and Managed With Coronary Computed Tomography Angiography and Fractional Flow Reserve Derived From Computed Tomography

Left main coronary artery thrombus (LMCA-T) is a rare disease state and diagnosed with invasive coronary angiography (ICA). We present a case of LMCA-T diagnosed with coronary computed tomography angiography (CTA) and treated without ICA in a patient who presented to a hospital in the middle of war zone in Erbil, Iraqi Kurdistan. Coronary CTA performed 1 month later demonstrated resolution of the thrombus. Fractional flow reserve computed from computed tomography (FFR-CT; HeartFlow, Redwood City, CA) performed retrospectively confirmed that the clot was not hemodynamically significant at the time of diagnosis. This case demonstrates the diagnostic capabilities of coronary CTA and FFR-CT when ICA is not readily available.

Anomalous coronary sinus communication to the left atrium

This report highlights an unusual anatomical finding with serious implications in clinical cardiac care. We present a case of a fistula or bridging vein originating from the left atrium (LA) and inserting into the coronary sinus (CS) which courses posteriorly to the right atrium and inserts near the superior vena cava, essentially serving as a left to right shunt in a 64-year-old woman presenting with chest pain. The coronary venous system serves as a vital access point in the placement of cardiac pacemakers and defibrillators. Coronary sinus anomalies are rare and often occur in isolation or in association with other vascular anomalies. The described conduit serves as a functional interatrial shunt, though likely with minimal hemodynamic significance given the low pressure state of the left and right atria. This case highlights the importance of understanding the coronary venous anatomy and its variations in terms of anatomic course, valves, diameter, angulation, relationship to coronary arteries. <Learning objective: Coronary CT angiography can provide detailed anatomical information for diagnosis and treatment of anomalous coronary sinus communication to the left atrium. Coronary sinus ablation may be necessary in atrial fibrillation refractory to pulmonary venous isolation. An important differential diagnosis to this anomaly is unroofed CS. Anomalous coronary sinus communication to the left atrium demonstrates anomalous bridging vein indirectly communicating the CS to the LA. However, unroofed CS demonstrates a direct CS to LA communication through a wall defect; the CS is usually enlarged.>.

Effect of statins on atherosclerotic plaque

Lipid lowering therapy has been the mainstay of cardiovascular risk reduction and prevention. Statin drugs have been shown to reduce serum cholesterol along with significant reduction in morbidity and mortality of cardiovascular disease. Whether these benefits are purely through lipid lowering or pleiotropic (cholesterol independent) effects has yet to be fully understood. Advances in cardiac imaging, from intravascular ultrasound to multi-detector coronary computed tomography angiography, have furthered our understanding of statin's effect on atherosclerotic plaque. Notably, statins play a role in plaque regression with reduction in lipid content. These drugs further stabilize atherosclerotic plaque with thickened fibrous caps and macrocalcification that serves to stabilize atheromas.

Arrhythmia in stem cell transplantation

Stem cell regenerative therapies hold promise for treating diseases across the spectrum of medicine. While significant progress has been made in the preclinical stages, the clinical application of cardiac cell therapy is limited by technical challenges. Certain methods of cell delivery, such as intramyocardial injection, carry a higher rate of arrhythmias. Other potential contributors to the arrhythmogenicity of cell transplantation include reentrant pathways caused by heterogeneity in conduction velocities between graft and host as well as graft automaticity. In this article, the arrhythmogenic potential of cell delivery to the heart is discussed.