Statewide Initiative to Reduce Patient Radiation Doses During Percutaneous Coronary Intervention.

BACKGROUND: Improved radiation safety practices are needed across hospitals performing percutaneous coronary intervention (PCI). This study was performed to assess the temporal trend in PCI radiation doses concurrent with the conduct of a statewide radiation safety initiative. METHODS: A statewide initiative to reduce PCI radiation doses was conducted in Michigan between 2017 and 2021 and included focused radiation safety education, reporting of institutional radiation doses, and implementation of radiation performance metrics for hospitals. Using data from a large statewide registry, PCI discharges between July 1, 2016, and July 1, 2022, having a procedural air kerma (AK) recorded were analyzed for temporal trends. A multivariable regression analysis was performed to determine whether declines in procedural AK over time were attributable to changes in known predictors of radiation doses. RESULTS: Among 131 619 PCI procedures performed during the study period, a reduction in procedural AK was observed over time, from a median dose of 1.46 (0.86-2.37) Gy in the first year of the study to 0.97 (0.56-1.64) Gy in the last year of the study (P<0.001). The proportion of cases with an AK ≥5 Gy declined from 4.24% to 0.86% over the same time period (P<0.0001). After adjusting for variables known to impact radiation doses, a 1-year increase in the date of PCI was associated with a 7.61% (95% CI, 7.38%-7.84%) reduction in procedural AK (P<0.0001). CONCLUSIONS: Concurrent with the conduct of a statewide initiative to reduce procedural radiation doses, a progressive and significant decline in procedural radiation doses was observed among patients undergoing PCI in the state of Michigan.

Physician Radiation Exposure During Endomyocardial Biopsy and Right Heart Catheterization.

BACKGROUND: Cardiologists performing coronary angiography (CA) and percutaneous coronary intervention (PCI) are at risk of health problems related to chronic occupational radiation exposure. Unlike during CA and PCI, physician radiation exposure during right heart catheterization (RHC) and endomyocardial biopsy (EMB) has not been adequately studied. The objective of this study was to assess physicians' radiation doses during RHC with and without EMB and compare them to those of CA and PCI. METHODS: Procedural head-level physician radiation doses were collected by real-time dosimeters. Radiation-dose metrics (fluoroscopy time, air kerma [AK] and dose area product [DAP]), and physician-level radiation doses were compared among RHC, RHC with EMB, CA, and PCI. RESULTS: Included in the study were 351 cardiac catheterization procedures. Of these, 36 (10.3%) were RHC, 42 (12%) RHC with EMB, 156 (44.4%) CA, and 117 (33.3%) PCI. RHC with EMB and CA had similar fluoroscopy time. AK and DAP were progressively higher for RHC, RHC with EMB, CA, and PCI. Head-level physician radiation doses were similar for RHC with EMB vs CA (P = 0.07). When physicians' radiation doses were normalized to DAP, RHC and RHC with EMB had the highest doses. CONCLUSION: Physicians' head-level radiation doses during RHC with EMB were similar to those of CA. After normalizing to DAP, RHC and RHC with EMB were associated with significantly higher physician radiation doses than CA or PCI. These observations suggest that additional protective measures should be undertaken to decrease physicians' radiation exposure during RHC and, in particular, RHC with EMB.

Comparison of Radiation Exposure Among Interventional Echocardiographers, Interventional Cardiologists, and Sonographers During Percutaneous Structural Heart Interventions.

Importance: Transesophageal echocardiography during percutaneous left atrial appendage closure (LAAO) and transcatheter edge-to-edge mitral valve repair (TEER) require an interventional echocardiographer to stand near the radiation source and patient, the primary source of scatter radiation. Despite previous work demonstrating high radiation exposure for interventional cardiologists performing percutaneous coronary and structural heart interventions, similar data for interventional echocardiographers are lacking. Objective: To assess whether interventional echocardiographers are exposed to greater radiation doses than interventional cardiologists and sonographers during structural heart procedures. Design, Setting, and Participants: In this single-center cross-sectional study, radiation doses were collected from interventional echocardiographers, interventional cardiologists, and sonographers at a quaternary care center during 30 sequential LAAO and 30 sequential TEER procedures from July 1, 2016, to January 31, 2018. Participants and study personnel were blinded to radiation doses through data analysis (January 1, 2020, to October 12, 2021). Exposures: Occupation defined as interventional echocardiographers, interventional cardiologists, and sonographers. Main Outcomes and Measures: Measured personal dose equivalents per case were recorded using real-time radiation dosimeters. Results: A total of 60 (30 TEER and 30 LAAO) procedures were performed in 60 patients (mean [SD] age, 79 [8] years; 32 [53.3%] male) with a high cardiovascular risk factor burden. The median radiation dose per case was higher for interventional echocardiographers (10.6 µSv; IQR, 4.2-22.4 µSv) than for interventional cardiologists (2.1 µSv; IQR, 0.2-8.3 µSv; P < .001). During TEER, interventional echocardiographers received a median radiation dose of 10.5 µSv (IQR, 3.1-20.5 µSv), which was higher than the median radiation dose received by interventional cardiologists (0.9 µSv; IQR, 0.1-12.2 µSv; P < .001). During LAAO procedures, the median radiation dose was 10.6 µSv (IQR, 5.8-24.1 µSv) among interventional echocardiographers and 3.5 (IQR, 1.3-6.3 µSv) among interventional cardiologists (P < .001). Compared with interventional echocardiographers, sonographers exhibited low median radiation doses during both LAAO (0.2 µSv; IQR, 0.0-1.6 µSv; P < .001) and TEER (0.0 µSv; IQR, 0.0-0.1 µSv; P < .001). Conclusions and Relevance: In this cross-sectional study, interventional echocardiographers were exposed to higher radiation doses than interventional cardiologists during LAAO and TEER procedures, whereas sonographers demonstrated comparatively lower radiation doses. Higher radiation doses indicate a previously underappreciated occupational risk faced by interventional echocardiographers, which has implications for the rapidly expanding structural heart team.

Suspended lead suit and physician radiation doses during coronary angiography.

OBJECTIVE: This study was performed to evaluate physician radiation doses with the use of a suspended lead suit. BACKGROUND: Interventional cardiologists face substantial occupational risks from chronic radiation exposure and wearing heavy lead aprons. METHODS: Head-level physician radiation doses, collected using real-time dosimeters during consecutive coronary angiography procedures, were compared with the use of a suspended lead suit versus conventional lead aprons. Multiple linear regression analyses were completed using physician radiation doses as the response and testing patient variables (body mass index, age, sex), procedural variables (right heart catheterization, fractional flow reserve, percutaneous coronary intervention, radial access), and shielding variables (radiation-absorbing pad, accessory lead shield, suspended lead suit) as the predictors. RESULTS: Among 1054 coronary angiography procedures, 691 (65.6%) were performed with a suspended lead suit and 363 (34.4%) with lead aprons. There was no significant difference in dose area product between groups (61.7 [41.0, 94.9] mGy·cm2 vs. 64.6 [42.9, 96.9] mGy·cm2 , p = 0.20). Median head-level physician radiation doses were 10.2 [3.2, 35.5] µSv with lead aprons and 0.2 [0.1, 0.9] µSv with a suspended lead suit (p < 0.001), representing a 98.0% reduced dose with suspended lead. In the fully adjusted regression model, the use of a suspended lead suit was independently associated with a 93.8% reduction (95% confidence interval: -95.0, -92.3; p < 0.001) in physician radiation dose. CONCLUSION: Compared to conventional lead aprons, the use of a suspended lead suit during coronary angiography was associated with marked reductions in head-level physician radiation doses.

A Novel Catheterization Laboratory Radiation Shielding System: Results of Pre-Clinical Testing.

BACKGROUND: This pre-clinical study evaluated the efficacy of a novel shielding system to reduce scatter radiation in the cardiac catheterization laboratory. METHODS: Using a scatter radiation phantom in a standard cardiac catheterization laboratory, a radiation physicist recorded radiation measurements at 20 reference points on the operator side of the table. Measurements were made with fluoroscopy and cine with the C-arm in the posterior-anterior (PA) and 40 degrees left anterior oblique (LAO) orientations. Scatter radiation doses were compared with and without use of the shielding system. RESULTS: Use of the shielding system was associated with >94.2% reduction in scatter radiation across all reference points in the PA and LAO projections with fluoroscopy and cine. With the shielding system, dose reductions at the location of the primary operator ranged from 97.8% to 99.8%. At locations of maximum scatter radiation, use of the shielding system resulted in dose reductions ranging from 97.8% to 99.8% with fluoroscopy and from 97.9% to 99.8% with cine. CONCLUSIONS: In this pre-clinical study, a novel radiation shielding system was observed to dramatically reduce scatter radiation doses. Based on these results, clinical testing is warranted to determine whether the shielding system will enable operators and staff to perform interventional procedures with less radiation exposure that may obviate the need to wear standard lead apparel. INDEXING WORDS: Radiation safety; occupational health; occupational hazard.

Multiple Cutaneous Cancers in an Interventional Cardiologist: Predominance in Unprotected Skin Nearest the Radiation Source.

A 70 year-old interventional cardiologist, who worked in the cardiac catheterization laboratory for >35 years, developed multiple skin cancers in regions not conventionally covered by protective lead apparel. The majority of lesions were left-sided, representing cutaneous regions in closest proximity to the radiation source. Although skin not covered by lead apparel often receives frequent sun exposure, a known risk factor for skin cancer, malignancies resulting exclusively from sun exposure would not in most cases be expected to have a left-sided predominance. Additional research is warranted to study the potential link between occupational radiation exposure and skin cancer risk.

Robotic telestenting performance in transcontinental and regional pre-clinical models.

OBJECTIVES: This study was conducted to evaluate the association of geographic distance with robotic telestenting performance by comparing performance measures in transcontinental and regional pre-clinical models of telestenting. BACKGROUND: Robotic telestenting, in which percutaneous coronary intervention (PCI) is performed on a remotely located patient, might improve PCI access, but has not been attempted over vast distances likely required to reach many underserved regions. METHODS: Telestenting performance was compared in regional (Boston to New York [206 miles]) and transcontinental (Boston to San Francisco [3,085 miles]) ex vivo models of telestenting, wherein a physician in Boston attempted robotic PCI on endovascular simulators in New York and San Francisco, respectively. PCI was attempted over both wired and fifth generation (5G)-wireless networks. Outcome measures included procedural success, procedural time, and perceived latency. RESULTS: Procedural success was achieved in 20 consecutive target lesions in the regional model and in 16 consecutive target lesions in the transcontinental model. The transcontinental model had a greater latency than the regional model over both wired (121.5 ± 2.4 ms vs. 67.8 ± 0.9 ms; p < .001) and 5G-wireless networks (162.5 ± 1.1 ms vs. 86.6 ± 0.6 ms; p < .001), but perceived latencies were graded "imperceptible" in all cases in both models. Transcontinental and regional models did not have significantly different procedural times over wired (4.1 ± 1.9 min vs. 9.0 ± 7.1 min; p = .051) or 5G-wireless (3.0 ± 0.6 vs. 6.3 ± 1.2; p = .36) networks. CONCLUSIONS: Transcontinental robotic manipulation of coronary devices is now possible and was not associated with adverse performance compared to robotic telestenting conducted regionally.

Patient Body Mass Index and Occupational Radiation Doses to Circulating Nurses During Coronary Angiography.

BACKGROUND: Patient BMI is associated with radiation doses received by interventional cardiologists, yet the association between patient BMI and nurse radiation doses is unknown. This study evaluated the association between patient body mass index (BMI) and nurse radiation doses during coronary angiography. METHODS: Nurse radiation doses were collected by real-time dosimeters during consecutive coronary angiography procedures and are reported as the personal dose equivalent (Hp10). Patient radiation doses were estimated using dose area product (DAP). Patient BMI was categorized in kg/m2 as <25.0, 25.0-29.9, 30.0-34.9, 35.0-39.9, and ≥40. Multiple regression analysis determined procedural factors independently association with nurse radiation doses. RESULTS: In 643 consecutive coronary angiography procedures, patient radiation doses increased significantly across increasing patient BMI categories (p < 0.001). Compared to a patient BMI <25, a patient BMI ≥40 was associated with a 2.3-fold increase in DAP (p < 0.001). Significant differences were also observed in nurse radiation doses across patient BMI categories (p = 0.036). Compared to a patient BMI <25, a patient BMI ≥40 was associated with a 4.0-fold increase in nurse radiation dose (BMI < 25: 0.3 [0.1, 1.3] µSv; BMI ≥ 40: 1.2 [0.2, 2.9] µSv; p = 0.003). By multiple regression analysis, each 1-unit kg/m2 increase in patient BMI was associated with a 3.3% increase in nurse radiation dose (p = 0.002). CONCLUSIONS: Patient BMI was significantly associated with nurse radiation doses during coronary angiography. These observations may have important implications on nurse radiation safety, especially in the setting of the ongoing obesity epidemic.

Institutional Variability in Patient Radiation Doses ≥5 Gy During Percutaneous Coronary Intervention.

OBJECTIVES: The aim of this study was to evaluate institutional variability in high radiation doses during percutaneous coronary intervention (PCI). BACKGROUND: It is unknown whether radiation safety practices are optimally applied across institutions performing PCI. METHODS: Using data from a large statewide registry, PCI discharges between July 1, 2016, and March 31, 2018, with a procedural air kerma (AK) recorded were analyzed. PCI procedures were grouped by the performing hospital, and institutional frequency of procedural AK ≥5 Gy was calculated. Fitted hierarchical Bayesian modeling was performed to identify variables independently associated with an AK ≥5 Gy. The performing hospital was included as a random effect in the hierarchical model. RESULTS: Among 36,201 PCI procedures at 28 hospitals, procedural AK was ≥5 Gy in 1,477 cases (4.1%), ≥10 Gy in 185 (0.5%), and ≥15 Gy in 105 (0.3%). The institutional frequency of procedural AK ≥5 Gy ranged from 0.0% to 10.9%. Bayesian modeling identified body mass index, dyslipidemia, diabetes, prior coronary bypass surgery, use of mechanical circulatory support, and the performing hospital as independent predictors of an AK ≥5 Gy. The median odds ratio for the performing hospital, representing an estimate of the contribution of interhospital variability in determining the odds of having a procedural AK ≥5 Gy, was 3.08 (95% confidence interval: 3.01 to 3.16). CONCLUSIONS: Wide variability exists in the institutional frequency of procedural AK ≥5 Gy during PCI. After accounting for patient characteristics and procedural variables, the performing hospital appears to be a major factor in determining patient radiation dose in contemporary PCI.

Patient Body Mass Index and Physician Radiation Dose During Coronary Angiography.

BACKGROUND: Consistent with the increasing prevalence of obesity in the general population, obesity has become more prevalent among patients undergoing cardiac catheterization. This study evaluated the association between patient body mass index (BMI) and physician radiation dose during coronary angiography. METHODS AND RESULTS: Real-time radiation exposure data were collected during consecutive coronary angiography procedures. Patient radiation dose was estimated using dose area product. Physician radiation dose in each case was recorded by a dosimeter worn by the physician and is reported as the personal dose equivalent (Hp10). Patient BMI was categorized as <25.0, 25.0 to 29.9, 30.0 to 34.9, 35.0 to 39.9, and ≥40. Among 1119 coronary angiography procedures, significant increases in dose area product and physician radiation dose were observed across increasing patient BMI categories ( P<0.001). Compared with a BMI <25, a patient BMI ≥40 was associated with a 2.1-fold increase in patient radiation dose (dose area product, 91.8 [59.6-149.2] versus 44.5 [25.7-70.3] Gy×cm2; P<0.001) and a 7.0-fold increase in physician radiation dose (1.4 [0.2-7.1] versus 0.2 [0.0-2.9] µSv; P<0.001). By multiple regression analysis, patient BMI remained independently associated with physician radiation dose (dose increase, 5.2% per unit increase in BMI; 95% CI, 3.0%-7.5%; P<0.0001). CONCLUSIONS: Among coronary angiography procedures, increasing patient BMI was associated with a significant increase in physician radiation dose. Additional studies are needed to determine whether patient obesity might have adverse effects on physicians, in the form of increased radiation doses during coronary angiography.

Impact of patient obesity on radiation doses received by scrub technologists during coronary angiography.

BACKGROUND: The impact of patient obesity on scrub technologist radiation dose during coronary angiography has not been adequately studied. METHODS: Real-time radiation exposure data were prospectively collected during consecutive coronary angiography cases. Patient radiation dose was estimated by dose area product (DAP). Technologist radiation dose was recorded by a dosimeter as the personal dose equivalent (Hp (10)). Patients were categorized according to their body mass index (BMI): <25.0, lean; 25.0-29.9, overweight; ≥30.0, obese. The study had two phases: in Phase I (N = 351) standard radiation protection measures were used; and in Phase II (N = 268) standard radiation protection measures were combined with an accessory lead shield placed between the technologist and patient. RESULTS: In 619 consecutive coronary angiography procedures, significant increases in patient and technologist radiation doses were observed across increasing patient BMI categories (p < 0.001 for both). Compared to lean patients, patient obesity was associated with a 1.7-fold increase in DAP (73.0 [52.7, 127.5] mGy × cm2 vs 43.6 [25.1, 65.7] mGy × cm2, p < 0.001) and a 1.8-fold increase in technologist radiation dose (1.1 [0.3, 2.7] µSv vs 0.6 [0.1, 1.6] µSv, p < 0.001). Compared to Phase I, use of an accessory lead shield in Phase II was associated with a 62.5% reduction in technologist radiation dose when used in obese patients (p < 0.001). CONCLUSIONS: During coronary angiography procedures, patient obesity was associated with a significant increase in scrub technologist radiation dose. This increase in technologist radiation dose in obese patients may be mitigated by use of an accessory lead shield.

Radiation Exposure Among Scrub Technologists and Nurse Circulators During Cardiac Catheterization: The Impact of Accessory Lead Shields.

OBJECTIVES: This study was performed to determine if the use of an accessory lead shield is associated with a reduction in radiation exposure among staff members during cardiac catheterization. BACKGROUND: Accessory lead shields that protect physicians from scatter radiation are standard in many catheterization laboratories, yet similar shielding for staff members is not commonplace. METHODS: Real-time radiation exposure data were prospectively collected among nurses and technologists during 764 consecutive catheterizations. The study had 2 phases: in phase I (n = 401), standard radiation protection measures were used, and in phase II (n = 363), standard radiation protection measures were combined with an accessory lead shield placed between the staff member and patient. Radiation exposure was reported as the effective dose normalized to dose-area product (EDAP). RESULTS: Use of an accessory lead shield in phase II was associated with a 62.5% lower EDAP per case among technologists (phase I: 2.4 [4.3] µSv/[mGy × cm2] × 10-5; phase II: 0.9 [2.8] µSv/[mGy × cm2] × 10-5; p < 0.001) and a 63.6% lower EDAP per case among nurses (phase I: 1.1 [3.1] µSv/[mGy × cm2] × 10-5; phase II: 0.4 [1.8] µSv/[mGy × cm2] × 10-5; p < 0.001). By multivariate analysis, accessory shielding remained independently associated with a lower EDAP among both technologists (34.2% reduction; 95% confidence interval: 20.1% to 45.8%; p < 0.001) and nurses (36.4% reduction; 95% confidence interval: 19.7% to 49.6%; p < 0.001). CONCLUSIONS: The relatively simple approach of using accessory lead shields to protect staff members during cardiac catheterization was associated with a nearly two-thirds reduction in radiation exposure among nurses and technologists.

Robotics in percutaneous cardiovascular interventions.

INTRODUCTION: The fundamental technique of performing percutaneous cardiovascular (CV) interventions has remained unchanged and requires operators to wear heavy lead aprons to minimize exposure to ionizing radiation. Robotic technology is now being utilized in interventional cardiology partially as a direct result of the increasing appreciation of the long-term occupational hazards of the field. This review was undertaken to report the clinical outcomes of percutaneous robotic coronary and peripheral vascular interventions. Areas covered: A systematic literature review of percutaneous robotic CV interventions was undertaken. The safety and feasibility of percutaneous robotically-assisted CV interventions has been validated in simple to complex coronary disease, and iliofemoral disease. Studies have shown that robotically-assisted PCI significantly reduces operator exposure to harmful ionizing radiation without compromising procedural success or clinical efficacy. In addition to the operator benefits, robotically-assisted intervention has the potential for patient advantages by allowing more accurate lesion length measurement, precise stent placement and lower patient radiation exposure. However, further investigation is required to fully elucidate these potential benefits. Expert commentary: Incremental improvement in robotic technology and telecommunications would enable treatment of an even broader patient population, and potentially provide remote robotic PCI.

Impact of robotics and a suspended lead suit on physician radiation exposure during percutaneous coronary intervention.

BACKGROUND: Reports of left-sided brain malignancies among interventional cardiologists have heightened concerns regarding physician radiation exposure. This study evaluated the impact of a suspended lead suit and robotic system on physician radiation exposure during percutaneous coronary intervention (PCI). METHODS: Real-time radiation exposure data were prospectively collected from dosimeters worn by operating physicians at the head- and chest-level during consecutive PCI cases. Exposures were compared in three study groups: 1) manual PCI performed with traditional lead apparel; 2) manual PCI performed using suspended lead; and 3) robotic PCI performed in combination with suspended lead. RESULTS: Among 336 cases (86.6% manual, 13.4% robotic) performed over 30weeks, use of suspended lead during manual PCI was associated with significantly less radiation exposure to the chest and head of operating physicians than traditional lead apparel (chest: 0.0 [0.1] µSv vs 0.4 [4.0] µSv, p<0.001; head: 0.5 [1.9] µSv vs 14.9 [51.5] µSv, p<0.001). Chest-level radiation exposure during robotic PCI performed in combination with suspended lead was 0.0 [0.0] µSv, which was significantly less chest exposure than manual PCI performed with traditional lead (p<0.001) or suspended lead (p=0.046). In robotic PCI the median head-level exposure was 0.1 [0.2] µSv, which was 99.3% less than manual PCI performed with traditional lead (p<0.001) and 80.0% less than manual PCI performed with suspended lead (p<0.001). CONCLUSIONS: Utilization of suspended lead and robotics were observed to result in significantly less radiation exposure to the chest and head of operating physicians during PCI.

Development and validation of a predictive screening tool for uninterpretable coronary CT angiography results.

BACKGROUND: Coronary CT angiography (CCTA) is an excellent tool for noninvasive assessment of coronary arteries in low- to intermediate-risk individuals. However, the accuracy of CCTA heavily depends on image quality. Our objective was to develop and validate a tool to predict pre-CCTA risk of obtaining an uninterpretable result in symptomatic patients. METHODS AND RESULTS: Among 8585 symptomatic patients, we identified variables independently associated with the presence of at least 1 uninterpretable major coronary segment to create the uninterpretable risk score (URS). This risk score was developed using both clinical variables and patient variables acquired at the time the CCTA was performed (heart rate and coronary calcium). The URS was then prospectively validated among an additional 915 symptomatic patients. The URS was predictive of uninterpretable results in both the development and the validation cohorts. For every 4-point increase in the URS (range, 0 to 12), the rate of at least 1 uninterpretable coronary segment per 100 CCTA studies increased ≈1.5 fold. Increased heart rate and coronary artery calcium score were predictive of uninterpretable CCTA study results. Uninterpretable results were associated with 3-month outcomes in the development cohort. CONCLUSIONS: The URS can categorize patients who are likely to have at least 1 uninterpretable major coronary segment on CCTA. This may aid in appropriate patient selection for CCTA and avoiding radiation exposure in those likely to have an uninterpretable study. Clinical Trial Registration- URL: http:///www.clinicaltrials.gov. Unique identifier: NCT00640068.

Refining the approach to renal artery revascularization.

Renal artery stenosis (RAS) is caused by a heterogenous group of diseases with different pathophysiology, clinical manifestations, treatment approaches, and outcomes. The 2 most common forms of RAS are fibromuscular dysplasia (FMD) and atherosclerosis (ARAS). Renovascular syndromes are broadly classified into renovascular hypertension and ischemic nephropathy, but these terms are misleading, because they imply a causal relationship between RAS, hypertension, and renal dysfunction, which is difficult to prove in humans. Data supporting renal revascularization are limited by heterogeneous causes of hypertension and renal dysfunction, insufficient understanding of the relationship between RAS and nephropathy, inconsistent techniques for revascularization, ambiguous terminology and end points to assess benefit, and lack of large-scale randomized trials. The purpose of this review is to enhance understanding of the epidemiology, clinical markers, and diagnosis of RAS; the relationship between RAS and important disease states; the distinction between renal ischemia and nephropathy; optimal revascularization techniques; and avoidance of renal injury.