Veteran Exposure to Radiation in the Cardiac Catheterization Laboratory
Thomas Tehsin Tsai MD MSc
VA Eastern Colorado Health Care System, Denver, CO
Denver, CO
Funding Period: July 2011 - June 2012

BACKGROUND/RATIONALE:
In the United States, there has been a dramatic rise in the number of complex diagnostic and therapeutic procedures performed in the cardiac catheterization laboratory exceeding 4 million cases per year.1 These procedures deliver doses of ionizing radiation from 300-3000 times that of a standard chest x-ray and are often associated with prolonged fluoroscopy times. As a result, patients are exposed to high radiation doses, and this has contributed to an increase in radiation-induced skin injury.2-5 Furthermore, exposure to ionizing radiation also increases the patient's risk for the development of solid cancers and leukemias. 6
Accordingly, the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) recently added a new provision to the list of events that are reviewable under its Sentinel Event Policy to include prolonged fluoroscopy with a cumulative dose of >15000 mSv to a single field. Yet, these procedures generally occur without radiation dose monitoring protocols to warn operators of high radiation doses to the patients and avoiding potential injury. Furthermore, there are many dose reduction techniques that can easily be implemented to mitigate the risk of immediate and long term radiation morbidity to the patient.
As such, the Food and Drug Administration and VA Central Office have identified radiation safety to be an area of high priority. The objectives of this RRP are to define the distribution of fluoroscopy time and radiation dose for procedures performed in the cardiac catheterization laboratory and to identify patient, provider and hospital factors associated with high radiation exposure. These initial aims are very achievable using the fluoroscopy and radiation dose data on over 50,000 patients in the Cardiovascular Assessment Reporting and Tracking for Cardiac Catheterization Laboratories data repository (CART-CL). Informed by the results of the initial aims, we will pilot a radiation safety tool-kit at the Denver and Ann Arbor VAMCs (education course in radiation reducing technologies, an in-lab monitoring protocol and data feedback to operators) focused on physicians and catheterization lab staff to increase radiation awareness and decrease patient radiation exposure in the catheterization lab. We will compare fluoroscopy and radiation doses before and after the pilot intervention. A highly qualified team of investigators experienced with using the Cardiovascular Assessment Reporting and Tracking for Cardiac Catheterization Laboratories data repository (CART-CL) and implementation projects within IHD-QUERI will complete the aims of this proposal.

OBJECTIVE(S):
1.Define the distribution of fluoroscopy time and radiation dose by procedure (e.g. coronary angiography, peripheral intervention, etc) performed in the VA cardiac catheterization laboratories
2.Assess patient, provider and hospital factors associated with the highest quartile of fluoroscopy time and radiation dose
3.Informed by specific aim 1 and 2, pilot a radiation safety tool-kit at the Denver and Ann Arbor VAMCs (1. provide focused education on radiation dose-reduction techniques, 2. provide an in-lab radiation monitoring protocol, and 3. provide monthly radiation physician report cards). We will then compare fluoroscopy time and radiation doses before (3 months) and after the intervention.

METHODS:
We will define the distribution of fluoroscopy time and effective radiation dose (mean, standard deviation, median, interquartile range, range, 25th and 75th percentiles) for the procedure categories listed below.
1.Coronary angiography without bypass grafts
2.Coronary angiography with bypass grafts
3.Percutaneous coronary intervention
4.Peripheral procedures
5.Electrophysiology Procedures
Stratified variables- Patients will be further stratified within peripheral procedures into diagnostic versus therapeutic procedure and inflow (iliac) vs. outflow (common and superficial femoral and popliteal artery) versus runoff (infrapopliteal) procedures. Electrophysiology procedures will be further stratified into dual versus single lead pacemaker implantation, dual versus single lead defibrillator implantation, biventricular lead placement, and ablation procedures.

E2. Data Analysis Specific Aim 2: Assess patient, provider, and hospital factors associated with the highest quartile of fluoroscopy time and radiation dose
Statistical Analysis: For each of the procedures categories listed above, we will use a hierarchical linear regression model to evaluate the association of fluoroscopy and effective radiation dose with patient, provider and hospital factors. This multi-level model will allow us to adjust for clustering at the provider and hospital levels and to determine the relative contribution of patient, provider, and hospital characteristics to variation in fluoroscopy time and effective radiation dose. Baseline characteristics will be included in the model. We will also use hierarchical logistic regression models to assess the likelihood that these factors are associated with fluoroscopy time or effective radiation dose within the highest quintile of radiation exposure for each procedure group.
Patient level variables: Age, gender, height, weight, hypertension, Dyslipidemia, prior MI, prior CHF, family h/o premature CAD, prior PCI, Prior CABG, ESRD, cerebrovascular disease, peripheral arterial disease, chronic lung disease, diabetes mellitus, presenting signs and symptoms
Patient/Procedure level variables: arterial access site (femoral, brachial, radial, other), intra-aortic balloon pump, mechanical ventricular support devices, coronary anatomy (left main, LAD, LCx, RCA), lesion characteristics (previously treated, graft lesion, high complexity, thrombus present, bifurcation lesion), procedure complications (MI, Cardiogenic shock, CVA/Stroke, Tamponade, vascular complication requiring treatment)
Provider level variables: Years in practice, board certification in cardiology, board certification in interventional cardiology
Hospital level variables: Teaching hospital, >250 beds, academic affiliation, VISN

FINDINGS/RESULTS:
Analysis pending

IMPACT:
We will report the variability of radiation exposure in the VA cardiac catheterization laboratories and approximate the patient, procedure, provider, and center factors responsible for this variability. If our intervention demonstrates a decrease in radiation exposure, we will expand to other sites by securing additional funding.

PUBLICATIONS:

Conference Presentations

1. Tsai TT. Improving Care During and After PCI: Optimal Use of Technology and Periprocedural Complications. Paper presented at: American Heart Association Annual Scientific Sessions; 2011 Nov 15; Orlando, FL.

DRA: Cardiovascular Disease, Other Conditions
DRE: Prevention
Keywords: QUERI Implementation
MeSH Terms: none