Coronary Artery Calcification in Pre-Atrial Fibrillation Ablation Scans: A Missed Opportunity?
Harmon E1, Allam S1, Kutinsky I2, Villines T1, Mehta N12
1University of Virginia Health System, Charlottesville, VA.2Department of Cardiology, Beaumont Health, Royal Oak, MI.
Key Words : Atrial Fibrillation, Calcification.
Dhanunjaya Lakkireddy, MD, FACC, FHRS
Executive Medical Director
The Kansas City Heart Rhythm Institute (KCHRI) @ HCA MidWest
12200, W 106th street
Overland Park Regional Medical Center
Overland Park, KS 66215
We read with great interest the recent article by Dunleavy et al. 1 describing the prevalence of coronary artery calcification (CAC) on pre-ablation computed tomography (CT) of the pulmonary veins (CTPV) in patients with atrial fibrillation (AF) in Ohio. Specifically, pre-ablation CT is performed as a non-gated high-pitch helical CT-scan with contrast timed for optimal pulmonary vein and left atrial opacification, followed by a 40-second delayed scan to more thoroughly evaluate the left atrial appendage for thrombus. However, the performance of pre-ablation CT-scans also offers in many patients an opportunity to identify subclinical coronary artery disease (CAD) and refine the intensity of preventive therapies. Thus, the frequency of CAC reporting on CTPV imaging, and its impact on statin prescriptions at time of hospital discharge was also investigated. The authors demonstrated that even though CAC is highly-prevalent in AF patients and is consistently reported on pre-ablation CTPV, its presence was not associated with increases in statin prescribing in eligible patients. Importantly, 34% of the studied cohort had known clinical CAD, a group in whom the presence and severity of CAC would not typically result in a change in management.
We recently reviewed 200 consecutive patients undergoing AF ablation at our academic tertiary care center from July 2017 through June 2018. Our cohort was comprised of mostly men (62%) with mean age 65 ± 11 years. Prevalence of clinical CAD was 22.5%. Of the 200 patients, 180 (90%) had CTPV prior to ablation, with 116 patients (64%) found to have CAC. Of the 116 patients with CAC on CTPV, 30 (26%) had clinical CAD. Conversely, of the 45 total patients with clinical CAD, 30 (67%) had CAC. The presence of CAC was noted in the conclusions section of only 38 (33%) of CAC-positive CTPV reports.
In total, there were 54 patients (29%) with CAC on pre-procedure CTPV not on baseline statin therapy, and only 6 (11.1%) were newly-prescribed a statin at time of hospital discharge. All six patients remained on statin therapy for at least one year following their discharge. This represents a missed opportunity to mitigate cardiovascular risk in roughly 89% of patients with CAC.
Our results from Virginia support the important work of the authors, and highlight a consistently-missed opportunity to optimize CAD management in patients with AF. First, current prevention guidelines endorse the use of CAC for guiding decision-making in many intermediate-risk patients 2. A recent expert consensus statement from the Society of Cardiovascular Computed Tomography and Society of Thoracic Radiology advocates for standardized reporting of the presence and severity of CAC as visualized on non-gated chest CT scans performed for other clinical reasons (e.g. not for dedicated CAC scoring) 3. Providers should utilize pre-ablation CT scans not only for procedural planning, but as an opportunity to refine patient cardiovascular risk and to better inform patients regarding the utilization and intensity of preventative therapies and lifestyle-coaching. Unfortunately, there remains significant heterogeneity in reporting of non-gated chest CT scans done for a variety of clinical indications.
Our observations support the conclusion by Dunleavy et al. and that institutions should consider initiating quality improvement protocols for optimal guideline-directed reporting and management. Going forward, we propose utilization of standardized measures of reporting CAC severity, number of coronary vessels involved, specific attention to left main CAC (a unique high-risk phenotype), and validated semi-automated measures of CAC severity in non-gated scans. This could modify the natural history of cardiovascular disease in this population.