Abstract
Background and objectives
Cardiac catheterization employs ionizing radiation, although imaging technologies have improved safety, the influence of procedural urgency on radiation exposure has rarely been investigated. This study compares radiation parameters in elective versus emergency cardiac catheterizations.
Methods
This prospective cohort study examined 108 patients (elective: 27; emergency: 81) undergoing cardiac catheterization at University Hospital between October 2014 and March 2015. All procedures were performed by a single operator utilizing the Allura Clarity X-ray system, reducing variability. Radiation metrics such as fluoroscopy time, cine time, Dose Area Product (DAP), and Air Kerma Product (KAP) were registered. Dosimeters were placed at the level of patients' heads and the level of operators' chests.
Results
In the crude analysis, cine time was significantly higher in emergency procedures than in elective procedures, with a difference of 22.69 ms (P = 0.009). In contrast, KAP demonstrated an inverse relationship, indicating a reduction of 770.48 mGy in emergency procedures (P = 0.021). Moving to the adjusted analysis, cine time remained significant. Additionally, DAP became significant, with a coefficient of 38,394.88 mGy·cm2 (P = 0.028). Meanwhile, KAP shifted to a direct relationship, showing an increase of 680.96 mGy in emergency procedures (P = 0.027). Confidence intervals improved following adjustment and became even narrower.
Conclusions
Procedure urgency is a significant factor in radiation exposure in cardiac catheterization. Technologies for dose reduction and protocol standardization are essential for minimizing risks to patients and providers.
Keywords: Cardiac catheterization, Radiation exposure, Procedural urgency, Dose area product, Cine time, Air Kerma Product, Fluoroscopy
1. Introduction
Radiation exposure during cardiac catheterizations is one of the most critical issues in interventional cardiology. It can be dangerous for both the patient and the interventional cardiologist. Radiation exposure can lead to long-lasting health effects, such as damage to the skin and eyes, and may contribute to the development of certain cancers [1]. Cardiac catheterization is the prime diagnostic and therapeutic intervention for coronary artery disease (CAD) that entirely relies on the use of ionizing radiation to obtain an image of the coronary vasculature [2]. Although these modalities critically guide clinical decision-making, the accumulation of radiation doses from repeated exposures can yield some long-term risks, including the development of cataracts and tissue injuries [3].This has brought enhanced awareness of the need to lay much emphasis on proper radiation safety practices [4].
Fluoroscopic systems like the Allura Clarity X-ray system integrate dose-reduction technologies, allowing for high-resolution images to be obtained through a low-radiation dose [5,6]. On the other hand, radiation exposure during catheterization depends not only on the equipment but also on patient and procedural-specific factors. For example, patient characteristics like Body Mass Index (BMI), arterial access route (radial versus femoral) [7], and procedural urgency (elective versus emergency) can influence radiation metrics such as Dose Area Product (DAP) and Air kerma product (KAP) [[8], [9], [10]]. Radial access is associated with average fluoroscopy times that are greater than that for femoral access, with greater possible radiation exposure; however, this could be offset by procedural competence or experience [11].
The objective of this prospective cohort study is to determine whether emergency or elective catheterization procedures are associated with higher levels of radiation exposure. Precisely, it evaluates key radiation parameters, including fluoroscopy time (minutes), number of runs, number of images, cine time (milliseconds), Dose Area Product (DAP in mGy·cm2), and Air Kerma Product (KAP in mGy).
2. Materials and methods
2.1. Study design and population
We prospectively enrolled 108 patients in this cohort study, who underwent cardiac catheterization procedures at university hospital from October 2014 to March 2015. All cardiac angiographies were performed by a single operator to ensure consistency and minimize potential operator-related differences. The machine system (Allura Clarity X-ray system) remained unchanged throughout the investigation period. Standard protective equipment, including screens and cloth barriers, was used.
Demographic and body mass index that may influence radiation exposure were collected from the catheterization laboratory database. Arterial access (radial vs. femoral) was documented, and patients were categorized based on the indication for coronary catheterization into elective and emergency procedures.
Procedural details were recorded, such as total fluoroscopic time, number of acquisition runs, and number of images captured. The fluoroscopic and cine angiographic images, collected before the Radiation Reduction Protocol, were obtained at a rate of 15 frames per second with standard image amplification set to 20 cm. Radiation exposure metrics, including Dose Area Product (DAP in mGy·cm2) and Air kerma product (KAP in mGy), were also measured. This study was conducted by the Declaration of Helsinki and received approval from the medical ethics committee of the university hospital, in Israel (139/14).
2.2. Radiation parameters (outcomes)
This study's endpoints included several radiation parameters, including fluoroscopy time (in minutes), number of runs, number of images, cine time (in milliseconds), Dose Area Product (DAP in mGy·cm2), and air kerma product (KAP in mGy). The primary outcome was to measure the DAP and the KAP and compare their values between the emergency and the elective groups. On the other hand, the secondary outcome aimed to measure DAP and KAP values between the primary operator, secondary operator, and the helping nurse using two dosimeters placed at their chest level, both above and below the protective gear concluding who had the highest radiation exposure. Patients' dosimeter levels were at the level of their heads.
2.3. Sample size calculation
The sample size was determined based on the KAP mGy parameter, utilizing data from prior research to estimate key statistical measures. Specifically, we calculated the means and standard deviations from the median and interquartile ranges (IQRs) reported in previous studies. [14,15].
We set the two-sided significance level (α) at 0.05 and aimed for a power of 0.80 to detect a meaningful difference between the two groups. The anticipated mean KAP for the elective group (m1) was 2074.75, while the mean for the emergency group (m2) was 4815, with standard deviations of 1003.72 and 3785.41, respectively. Based on these parameters, our calculations indicated that a total sample size of 36 participants would be necessary, resulting in 18 participants per group. This sample size will ensure sufficient power to detect differences in radiation exposure between elective and emergency groups (see eAppendix 1 in Supplement 1 for details).
2.4. Inclusion and exclusion criteria
This study included patients aged ≥18 years who underwent elective or emergency coronary catheterization at university hospital between October 2014 and March 2015, with documented arterial access (radial or femoral) and complete procedural details, including fluoroscopy time, acquisition runs, and radiation metrics (DAP and KAP). Cases with incomplete procedural records or periprocedural mortality were excluded. (For further details, see eAppendix 2 in Supplement 1 and Fig. 1).
Fig. 1.
Study flow chart.
2.5. Statistical analysis
Unadjusted comparisons of demographic characteristics, laboratory values, and procedure measurements between elective and emergency procedure cohorts were conducted using Student's t-test for continuous variables. Continuous variables were tested for normality using the Shapiro-Wilk test; those with abnormal distributions were presented as median and interquartile ranges(Q1-Q3), and analyzed with the Wilcoxon rank-sum (Mann–Whitney) test. Categorical variables were compared using Fisher's exact test, with results expressed as counts and percentages. All reported p-values are two-sided, with a significance threshold set at p < 0.05.
Unadjusted comparisons of influencing factors (Age, BMI, Male, Number of Diseased vessels, Number of Balloon inflations, and Number of Implanted stents) on radiation parameters (fluoroscopy time, number of runs, number of images, cine time, DAP, and KAP) in 108 patients undergoing cardiac catheterization were conducted using linear regression (see eAppendix 3 in Supplement 1 for details).
We employed a multivariable linear regression model to control for confounding factors in analyzing the relationship between the primary predictor in our study (distinguishing between elective and emergency procedures) and various radiation parameters (fluoroscopy time, number of runs, number of images, cine time, DAP, and KAP) in 108 patients undergoing cardiac catheterization (see eAppendix 4 in Supplement 1 for Methodological details).
3. Results
Table 1 presents a comparative analysis of demographic and procedural characteristics between patients undergoing elective (n = 27) and emergency (n = 81) cardiac catheterization procedures. The mean age of elective patients was 61.59 years, while emergency patients' mean was 64.65 years, with a p-value of 0.26 indicating no significant difference. The male percentage was 72.84 % for elective and 81.48 % for emergency patients (p = 0.44), also showing no significant difference. The BMI was 29.32 for elective patients and 28.10 for emergency patients (p = 0.26), further reflecting no significant difference. Procedural characteristics, including access routes (p = 0.79) and the number of diseased vessels (p = 0.27), showed no significant differences. The procedure time was similar for both groups, with a mean of 30.59 min for elective and 31.61 min for emergency procedures (p = 0.85).
Table 1.
Demographic and procedural characteristics in elective versus emergency cardiac catheterization patients.
| Variables | Elective procedure (n = 27) | Emergency procedure (n = 81) | P value | |
|---|---|---|---|---|
| Demographics | ||||
| Age (years) | 61.59 ± 12.71 | 64.65 ± 12.27 | 0.26a | |
| Male | 59 (72.84) | 22 (81.48) | 0.44b | |
| BMI | 29.32 ± 5.761 | 28.10 ± 4.51 | 0.26a | |
| Contrast allergy | 0 (0.00) | 1 (1.23) | 1.00b | |
| Hypertension | 21 (77.78) | 55 (67.90) | 0.46b | |
| Diabetes | 34 (41.98) | 10 (37.04) | 0.821b | |
| Dyslipidemia | 18 (66.67) | 38 (46.91) | 0.081b | |
| Active smoker | 9 (33.33) | 28 (34.57) | 1.00b | |
| Post CABG | 5 (18.52) | 16 (19.75) | 1.00b | |
| EF | 48.7 ± 0.11 | 45.22 ± 0.10 | 0.13a | |
| Laboratory values | ||||
| Creatinine (mg/dL) | 0.94 ± 0.19 | 1.11 ± 0.75 | 0.242a | |
| Hemoglobin (g/L) | 13.84 ± 1.74 | 12.85 ± 2.49 | 0.05a | |
| Procedure | ||||
| Vascular access | Femoral artery | 1 (3.70) | 8 (9.88) | 0.791 |
| Radial artery | 26 (96.30) | 73 (90.12) | ||
| Diseased vessels | No | 9 (33.33) | 19 (23.46) | 0.58b |
| Single | 8 (29.63) | 25 (30.86) | ||
| Multiple | 10 (37.04) | 37 (45.68) | ||
| Number of diseased vessels | 1 (1–3) | 1 (0–2) | 0.27C | |
| Implanted stents | NO | 16 (59.26) | 34 (41.98) | 0.336b |
| Single | 9 (33.33) | 35 (43.21) | ||
| Multiple | 2 (7.41) | 12 (14.81) | ||
| Number of implanted stents | 0 (0–1) | 0 (0–1) | 0.28C | |
| Balloon inflations | No | 18 (66.67) | 45 (55.56) | 0.37b |
| Yes | 9 (33.33) | 36 (44.44) | ||
| Balloon inflations median (Q1-Q3) | 0 (0–2) | 0 (0–3) | 0.218c | |
| CTO | 0 (0.00) | 2 (2.50) | 1.00b | |
| Bifurcation (true) n, | 0 (0.00) | 2 (2.50) | 1.00b | |
| Temporary pacemaker | 1 (3.70) | 2 (2.50) | 1.00b | |
| Procedure time (min) | 30.59 ± 23.54 | 31.61 ± 25.02 | 0.85a | |
| Contrast material (ml) | 76.51 ± 46.27 | 101.30 ± 74.21 | 0.10a | |
BMI – Body Mass Index; CABG – Coronary Artery Bypass Graft; EF – Ejection Fraction; CTO-Chronic Total Occlusion.
Independent t-test.
Fisher's exact.
Wilcoxon rank-sum (Mann–Whitney) test. Data presented mean ± SD or median (Q1-Q3) or n, %.
Table 2 presents a detailed statistical analysis of factors influencing radiation parameters during cardiac catheterization procedures, including numerical coefficients, p-values, and confidence intervals for each factor.
Table 2.
Factors influencing radiation parameters.
| Factors | Values represent | Radiation parameters |
|||||
|---|---|---|---|---|---|---|---|
| Fluoroscopy time (min) | Runs (num) | Images (num) | Cine time (ms) | DAP (mGycm2) | KAP (mGy) | ||
| Age (years) | Coefficient | 0.019 | −0.078 | −3.24 | 0.131 | −78.38 | 7.41 |
| P-value | 0.786 | 0.363 | 0.52 | 0.70 | 0.901 | 0.55 | |
| 95 % CI | (−0.123, 0.163) | (−0.248, 0.09) | (−13.13, 6.64) | (−0.56, 0.823) | (−1313, 1156) | (−16.9, 31.79) | |
| BMI | Coefficient | −0.163 | −0.214 | −12.59 | 1.47 | 3000 | 51.25 |
| P-value | 0.30 | 0.306 | 0.279 | 0.09 | 0.05 | 0.076 | |
| 95 % CI | (−0.477, 0.149) | (−0.623, 0.195) | (−35.4, 10.21) | (−0.253, 3.20) | (−14.78, 6016) | (−5.28, 107) | |
| Male | Coefficient | 0.09 | 3.34 | 230.0 | 13.01 | 53,776 | 971.5 |
| P-value | 0.95 | 0.12 | 0.068 | 0.191 | 0.001 | 0.002 | |
| 95 % CI | (−3.70, 3.90) | (−0.945, 7.63) | (−16.80, 476) | (−6.50, 32.52) | (21,240, 86,311) | (342.8, 1600) | |
| Number of diseased vessels | Coefficient | −1.25 | 3.673 | 254.5 | 14.33 | 30,568 | 628.51 |
| P-value | 0.081 | 0.000 | 0.000 | 0.000 | 0.000 | 0.000 | |
| 95 % CI | (−2.67, 0.154) | (1.72, 5.617) | (116.46, 392) | (7.66, 21) | (14,462, 46,673) | (316.2, 940.8) | |
| Number of balloon inflations | Coefficient | −0.180 | 3.08 | 161.23 | 8.39 | 21,303 | 441.29 |
| P-value | 0.39 | 0.000 | 0.000 | 0.000 | 0.000 | 0.000 | |
| 95 % CI | (−0.59, 0.238) | (2.406, 3.77) | (101.9, 220.5) | (5.169, 11.61) | (10,386, 32,220) | (296.3, 586.2) | |
| Number of implanted stents | Coefficient | 1.90 | 9.56 | 527.9 | 36.41 | 78,512 | 1505.95 |
| P-value | 0.12 | 0.000 | 0.000 | 0.000 | 0.000 | 0.000 | |
| 95 % CI | (−0.49, 4.31) | (6.370, 12.75) | (325.7, 730) | (23.01, 49.80) | (40,983, 1,160,420) | (850.3, 2161) | |
DAP – Dose Area Product; KAP – Kerma Air Product; CI – Confidence Interval.
Age and BMI were not significantly associated with any of the radiation parameters evaluated, including fluoroscopy time, number of runs, images, cine time, DAP, and KAP. Both variables demonstrated p-values above 0.05 across all measures, indicating no meaningful impact on these parameters. On the other hand, the male sex showed a significant association with higher radiation parameters for DAP and KAP with a coefficient of 53,776 (95 % CI: 21,240 to 86,311, p = 0.001) and a coefficient of 971.5 (95 % CI: 342.8 to 1600, p = 0.002), respectively. However, being a male didn't influence other radiation parameters, including fluoroscopy time, runs, images, and cine time.
Number of diseased vessels variable was significantly associated with all Radiation parameters including runs (coefficient = 3.673, 95 % CI: 1.72 to 5.617, p = 0.000), images (coefficient = 254.5, 95 % CI: 116.46 to 392, p = 0.000), cine time (coefficient = 14.33, 95 % CI: 7.66 to 21, p = 0.000), DAP (coefficient = 30,568, 95 % CI: 14,462 to 46,673, p = 0.000), and KAP (coefficient = 628.51, 95 % CI: 316.2 to 940.8, p = 0.000), except Fluoroscopy time. Furthermore, the number of balloon inflations variable was also significantly associated with all Radiation parameters including runs (coefficient = 3.08, 95 % CI: 2.406 to 3.77, p = 0.000), images (coefficient = 161.23, 95 % CI: 101.9 to 220.5, p = 0.000), cine time (coefficient = 8.39, 95 % CI: 5.169 to 11.61, =0.000), DAP (coefficient = 21,303, 95 % CI: 10,386 to 32,220, p = 0.000), and KAP (coefficient = 441.29, 95 % CI: 296.3 to 586.2, p = 0.000), except Flouroscopy time. Finally, the number of implanted stents was also significantly associated with all Radiation parameters including runs (coefficient = 9.56, 95 % CI: 6.370 to 12.75, p = 0.000), images (coefficient = 527.9, 95 % CI: 325.7 to 730, p = 0.000), cine time (coefficient = 36.41, 95 % CI: 23.01 to 49.80, p = 0.000), DAP (coefficient = 78,512, 95 % CI: 40,983 to 116,042, p = 0.000), and KAP (coefficient = 1505.95, 95 % CI: 850.3 to 2161, p = 0.000) except, Fluoroscopy time.
eFigure 1 illustrates the linear relationships between various influencing factors and radiation parameters, highlighting key findings from Table 2. In eFigure 1A, runs (y-axis) show a strong positive association with the number of implanted stents (coefficient = 9.56), followed by the number of diseased vessels (3.673) and balloon inflations (3.08), with each additional stent increasing Runs significantly. eFigure 1B depicts a similar trend for Images (y-axis), where implanted stents exhibit the strongest relationship (coefficient = 527.9), followed by diseased vessels (254.5) and balloon inflations (161.23). For Cine Time (eFigure 1C), implanted stents again dominate (coefficient = 36.41), followed by diseased vessels (14.33) and balloon inflations (8.39). eFigures 1D and 2E explore Dose Area Product (DAP) and Air Kerma Product (KAP) relationships, respectively, showing that implanted stents have the highest impact on DAP (coefficient = 78,512) and KAP (coefficient = 1505.95), with male sex, diseased vessels, and balloon inflations contributing variably. (See eFiguer1 in supplemental 1 for more.)
Table 3 summarizes the crude and adjusted regression coefficients for radiation parameters between elective and emergency procedures.
Table 3.
Crude and adjusted regression for radiation parameters between elective and emergency procedures.
| Groups | Values represent | Fluro time (min)c | Runs (num)c | Images (num)d | Cine time (ms)c | DAP (mGycm2)b | KAP (mGy)a |
|---|---|---|---|---|---|---|---|
| Crude | |||||||
| Elective procedure (n = 27) | Reference group | ||||||
| Emergency procedure (n = 81) | Regression coefficient | −0.543 | 3.839 | 218.493 | 22.69 | 33,460.8 | −770.48 |
| P-value | 0.809 | 0.106 | 0.131 | 0.009 | 0.054 | 0.021 | |
| 95 % confidence interval | −4.937, 3.851 | −0.810, 8.48 | −65.10, 502 | 5.783, 39.59 | −628.45, 67,550 | −1424, −116 | |
| Adjusted | |||||||
| Elective procedure (n = 27) | Reference group | ||||||
| Emergency procedure (n = 81) | Regression coefficient | −0.65 | 1.056 | 24.628 | 12.193 | 38,394.88 | 680.96 |
| P-value | 0.764 | 0.608 | 0.767 | 0.048 | 0.028 | 0.027 | |
| 95 % confidence interval | −4.948, 3.63 | −2.98, 5.09 | −138.2, 187.46 | 0.091, 24.29 | 4059, 72,730 | 79.18, 1282 | |
DAP – Dose Area Product; KAP – Kerma Air Product.
Adjusted for male and diseased vessels.
Adjusted for male.
Adjusted for diseased vessels and implanted stents.
Adjusted for balloon inflations and implanted stents.
In the crude analysis, cine time was significantly higher in emergency procedures compared to elective ones, with a regression coefficient of 22.69 milliseconds with p-value = 0.009. This means that, on average, emergency procedures increase cine time by 22.69 ms than elective ones. In contrast, KAP exhibited an inverse relationship, with a regression coefficient of −770.48 mGy (p = 0.021), indicating that emergency procedures were associated with a 770.48 mGy reduction in KAP compared to elective procedures.
In the adjusted analysis, the association between cine time and emergency procedures remained significant, although the coefficient decreased to 12.193 ms (p = 0.048). Surprisingly, DAP, which was not significant in the crude analysis (p = 0.054), became significant after adjustment, with a coefficient of 38,394.88 mGy·cm2 and a p-value = 0.028. On the other hand, KAP shifted from an inverse relationship (−770.48 mGy) to a direct one, with a coefficient of 680.96 mGy and a p-value = 0.027, indicating that emergency procedures increased KAP by 680.96 mGy compared to elective ones.
Confidence intervals also highlight improved precision after adjustment. For cine time, the crude interval ranged from 5.783 to 39.59 ms, narrowing to 0.091 to 24.29 ms in the adjusted analysis. Similarly, DAP's interval tightened from −628.45 to 67,550 mGy·cm2 in the crude model to 4059 to 72,730 mGy·cm2 after adjustment. Finally, KAP's interval also showed significant improvement, narrowing from −1424 to −116 mGy in the crude model to 79.18 to 1282 mGy in the adjusted analysis. Overall, these findings demonstrate that adjusting for confounding variables such as gender, number of diseased vessels, and number of implanted stents improves the reliability of the observed relationships.
Referring to Table 3, cine time was statistically significant in the adjusted analysis in the emergency group, with p-value = 0.048. Fig. 2A illustrates that the mean cine time for emergency procedures was 112.39 ms, compared to 89.70 ms for elective procedures. This highlights that emergency procedures are associated with higher cine time, reflecting greater radiation exposure in this parameter compared to elective procedures.
Fig. 2.
Violin charts showing means of Cine Time, DAP, and KAP in both Elective and Emergency Procedures groups: A. Cine Time. B. DAP. C. KAP.
Referring to Table 3, the Dose Area Product (DAP) was statistically significant in the adjusted analysis in the emergency group, with p-value = 0.028. In Fig. 2B, the mean DAP for emergency procedures was 128,986.1 mGy·cm2, while the mean for elective procedures was 95,525.2 mGy·cm2. This indicates that emergency procedures are associated with substantially higher DAP, suggesting increased overall radiation exposure in emergency cases compared to elective ones.
Referring to Table 3, the Karma Air Product (KAP) was statistically significant in the adjusted analysis in the emergency group, with p-value = 0.027. In Fig. 2C, elective procedures had a mean KAP of 1875.95 mGy. In contrast, emergency procedures exhibited a higher mean KAP of 2646.43 mGy, further underscoring the increased radiation exposure associated with emergency procedures.
The first operator was most exposed to the mean of 10.68 mSV followed by 4.47 mSv, for the second operator and 0.6 mSv for the rotating nurse. Interestingly, the dosimeter under the lead aprons measured lower radiation exposition in the first operator 0.1 mSv compared with the second operator 0.41 mSv (see eFigures 2 in Supplement 1 for details).
4. Discussion
In this study, we show that radiation exposure during emergency cardiac catheterization is higher than in elective procedures. Emergency procedures were associated with significantly higher values of cine time, Dose Area Product (DAP), and Air Kerma Product (KAP) when compared to elective procedures, after adjusting for potential confounders. These results provide evidence regarding the influence of procedural urgency on radiation exposure metrics, which may affect both the patient and the operator's safety.
This study identified several demographic traits for investigation; however, a deeper discussion of some of these qualities would be beneficial. For instance, while not statistically significant in our analysis, age, obesity, and conditions like diabetes and hypertension are known to influence radiation exposure and procedure complexity. Although there were no changes in BMI between the groups in our study, higher BMI may impact imaging quality and necessitate higher radiation doses [16].
It was shown that the access routes did not significantly differ between the groups, with most of the procedures performed by a Radial approach. This arguably suggests an overall trend within interventional cardiology toward radial access, along with its lower associated complication rates and shorter recovery times despite its longer radiation exposure [[17], [18], [19]]. Moreover, in another study, the results revealed a notably lower incidence of access site complications in the radial group (11.4 %) compared to the femoral group (22.9 %). This included a decreased rate of major bleeding events (2.3 % vs. 8.6 %) and a shorter median duration of hospitalization (three days versus five days) [20]. Surprisingly, femoral access was utilized in this study slightly more in emergencies (9.88 %) than in elective procedures (3.70 %).
Fluoroscopy time, one of the most important determinants of radiation exposure, differed very few between elective and emergency procedures in our study. Even after adjustment, no significant difference was seen between the two study groups. This contradicts studies such as [21,22] who reported an increase in fluoroscopy times in emergency cases due to the increased complexity of the procedures. In the matter of transforming to safer procedure, another study comparing intracardiac echocardiography (ICE) versus traditional fluoroscopy (TF) in patients undergoing pulmonary vein isolation (PVI) found that a comparison of 47 propensity score-matched pairs out of 156 patients undergoing pulmonary vein isolation (PVI) showed that those using ICE achieved significantly higher success rates for the first transseptal and experienced lower radiation exposure, including reduced radiographic contrast agent usage, shorter fluoroscopy time (5.7 min vs. 7.6 min), and lower fluoroscopy dose compared to patients using TF [23]. Similarly, fluoroscopy time (FT) was 3 min for CA and 14 min for PCI in prior research [24]. The advanced imaging technology used in our study, namely the Allura Clarity X-ray system, might have played a crucial role in that aspect by optimizing procedural efficiency. These results highlight the necessity to prioritize the advancement of imaging techniques, which improve procedural safety while still preserving the essential diagnostic and therapeutic benefits of fluoroscopy in cardiac interventions.
In contrast, Cine time, a critical parameter in radiation exposure, was significantly higher for emergency versus elective cardiac catheterization procedures. This difference reflects the greater reliance on long and complex imaging during emergencies. This is consistent with Dong et al. [25], who suggested that prolonged cine images are often necessary in emergencies to provide a more thorough visual image and repeated assessments during the procedure. although cine accounts for just 5–30 % of the total operation time of the X-ray tube, it contributes to approximately 80 % of the overall radiation exposure for both staff and patients. Substantial reductions in radiation exposure can be achieved by recognizing when cine imaging is in use and implementing appropriate safety measures [26]. This makes evident that procedural urgency significantly affects cine time, thus implying the development of precise strategies for dose reduction, such as limiting cine duration without losing diagnostic accuracy.
Higher numbers of acquisition runs and images were correlated in emergency procedures, showing more need for detailed visualization in urgent scenarios. However, these differences were statistically non-significant when adjustments were made. Such findings corroborate the work done by Crowhurst et al. [27], who noted a similar trend in emergency cases. Small differences, as found in this research, suggest that systematic procedural protocols may bring about only modest changes in the management of the imaging demands of emergency cases and probably allow for limited radiation exposure.
DAP is an important metric for radiation exposure during imaging; it is the total amount of energy from radiation received by the patient [28], was significantly greater in emergency procedures. The findings relate to those of Asada et al. [21], who explained that increased DAP was due to greater complexity and extended imaging demands of emergency interventions. In another study, they found that the patient dose levels (DAP) were with a median of 49.3 Gy·cm2 for PCI procedures. [29]. Also, our findings are consistent with Rodríguez-Perálvarez et al. (2011), who found that therapeutic procedures and DAP are closely linked, with greater procedural complexity resulting in significantly higher DAP values [30]. Moreover, the RadiCure trial attempted to assess the factors affecting radiation exposure during cardiac catheterization. Reports suggested that procedural urgency, the operator's experience, and the number of diseased vessels greatly affected DAP and fluoroscopy times [31]. Despite these challenges, advanced dose-reduction technologies, including low-frame-rate imaging, can mitigate this radiation exposure. Our findings advocate the need for institutions to adapt their innovations to bring about a balance between procedural efficacy and radiation safety.
KAP is therefore reasonably justifiably increased in the emergency group. Prolonged imaging time, repeated evaluations, and increased requests for detailed visualization were propounded to have caused this rise. Factors like implanted stents and diseased vessels greatly increased the radiation exposure burden, signifying the impact of procedural intricacy on safety. This finding corroborates those laid elsewhere by Zanca et al. [16] who proposed the prolonged imaging reasons in emergencies as prime contributing factors to raised KAP values. Additionally, another study found that the median PKA was 63 Gy·cm2 for coronary angiography (CA) and 125 Gy·cm2 for percutaneous coronary intervention (PCI), showing a significant difference (p < 0.001). Additionally, both PKA and FT demonstrated a significant increase (p < 0.05) across BMI classes in CA procedures [24]. The precise KAP measurement obtained from all dosimeters in this study indicates that KAP is a valid measure in radiation exposure monitoring. Advanced imaging technologies, such as Allura Clarity, as used in this study, are developed to ionize patients' lesser doses due to their efficiency in nonlinear modes. However, persistent differences in KAP indicate a requirement for appropriate radiation reduction strategies for emergency cases. Standardization of KAP monitoring could help further improve safety and minimize these discrepancies.
This analysis revealed the operator and staff member urgency during emergency procedures: higher radiation doses for the first operator. In particular, dosimeters placed under lead aprons showed considerably lower exposure levels relative to those placed outside this protective gear, thus underscoring the effectiveness of such protective equipment. These findings are also in agreement with Ko et al. [32], who concluded that shielding was required to minimize the amount of occupational exposure. This emphasizes the need for routine dosimeter usage, correct placement, and adherence to shielding protocols to protect healthcare workers from the cumulative risks posed by radiation.
This study had considerable strengths, including standardized protocols, such as a single operator and an identical fluoroscopy system (Allura Clarity X-ray), which minimized variability and increased reliability. A broad spectrum of radiation metrics, namely DAP, KAP, cine time, and fluoroscopy time, were evaluated to paint a nuanced picture of procedural radiation exposure. Supplementing dosimeters placed above and below the protective gear adds to the accuracy of occupational exposure measurements and suggests improvements in radiation safety practices. Multivariable regression analysis with adjustments for several diseased vessels, male gender, number of balloon inflations, and number of implanted stents further reinforced the reliability of the findings of this study. The inclusion of both elective and emergency procedures also improved its external validity by revealing differences in radiation exposure based on the different clinical urgencies and utilizing more than one dosimeter helped to provide a wave of validity to the measurement of exposure and the variability in exposure [16,17].
On the other hand, some important limitations must be considered. The study also had a small sample size (n = 108), which weakened the statistical power. Furthermore, its single-center design may limit generalizability to other settings with different patient populations, operator practices, or imaging systems. Though variability was reduced by having a single operator, this created bias, as the results may not reflect any common approaches to the procedure. The cohort study design of this study precluded determining cumulative radiation effects over time. Besides, the fact that the comparison of the Allura Clarity system was never made with other imaging technologies limits its contextualization in the performance of others. The underrepresentation of rare procedures, such as chronic total occlusions, further restricted the exploration of their impact on radiation exposure. The above restrictions underline the need for larger multicenter studies to critically assess the situation with longer follow-ups.
Future studies should analyze the comparative effectiveness of advanced imaging systems other than Allura Clarity to evaluate the impact of various dose-reduction technologies on radiation exposure when performing both emergency and elective procedures. Furthermore, it may merit further consideration to investigate the long-term health effects of serial radiation exposure on the patient as well as the healthcare workers, especially in terms of cumulative risks. Studying the impact of patient-specific factors like comorbidities such as diabetes or renal dysfunction may provide insights into procedural complexity and radiation demand. Lastly, it is very important to optimize the protocol of emergency interventions to balance the need for rapid imaging against minimizing radiation exposure while ensuring procedural effectiveness and safety.
5. Conclusion
This study highlights that procedural urgency significantly influences radiation exposure during cardiac catheterization, with emergency procedures showing higher cine time, DAP, and KAP than elective ones. These findings emphasize the need for advanced imaging systems, standardized protocols tailored to such procedures, and further research into the long-term effects of radiation exposure and patient-specific factors. By tackling these aspects, future efforts can optimize patient and provider safety while maintaining procedural efficiency in interventional cardiology.
Consent section
Written informed consent was obtained from all patients involved in this study before their participation. Images used in the manuscript are anonymized and comply with patient privacy standards.
CRediT authorship contribution statement
Haitham Abu Khadija: Supervision, Writing – original draft, Writing – review & editing. Mohammad Alnees: Formal analysis, Methodology, Project administration, Software, Supervision, Writing – original draft, Writing – review & editing. Jacob George: Project administration, Supervision, Writing – original draft, Writing – review & editing. Manar Bakry: Conceptualization, Data curation. Dalia Abasi: Conceptualization, Data curation. Nizar Abu Hamdeh: Conceptualization, Data curation, Writing – original draft, Writing – review & editing. Mahdi Awwad: Conceptualization, Data curation, Writing – original draft. Alena Kirzhner: Writing – review & editing. Tal Schiller: Conceptualization, Data curation, Writing – original draft. Alex Blatt: Conceptualization, Data curation, Supervision. Gabby Elbaz-Greener: Conceptualization, Data curation, Supervision.
Ethical consideration
This study was conducted by the Declaration of Helsinki and received approval from the medical ethics committee of the university hospital, in Israel (139/14).
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Footnotes
Supplementary data to this article can be found online at https://doi.org/10.1016/j.ahjo.2025.100530.
Contributor Information
Mohammad Alnees, Email: A2011z2012z2013@gmail.com.
Alex Blatt, Email: alexbl31@clalit.org.il.
Gabby Elbaz-Greener, Email: gabbyelbaz100@gmail.com.
Appendix A. Supplementary data
Supplementary material
Data availability
The datasets generated and/or analyzed during the current study are available upon reasonable request from the corresponding author.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Supplementary material
Data Availability Statement
The datasets generated and/or analyzed during the current study are available upon reasonable request from the corresponding author.