Optimizing Radiation Safety in the Cardiac Catheterization Laboratory: A Practical Approach.

Reducing radiation exposure during cardiovascular catheterization is of paramount importance for both patient and staff safety. Over the years, advances in equipment and application of radiation safety protocols have significantly reduced patient dose and operator exposure. This review examines the current status of radiation protection in the cardiac and vascular catheterization laboratory and summarizes best practices for minimizing radiation exposure.

Comparison of radiation dose between different fluoroscopy systems in the modern catheterization laboratory: Results from bench testing using an anthropomorphic phantom.

BACKGROUND: Variations in radiation dose between various X-ray systems have received limited study. OBJECTIVE: We examined the impact of X-ray system type on patient radiation dose during cardiac catheterization. METHODS: An anthropomorphic phantom was used in a series of standardized experiments that involved 15 sec of continuous cineangiography in 7 projections. Three to seven experiments were performed in four commonly used X-ray systems: Innova IGS (GE Healthcare), Integris Allura FD20 (Philips), Allura Clarity (Philips), and Artis one (Siemens). Phantom radiation dose was measured with a dedicated X-ray dosimetry system (Gafchromic radiology film and Film QA XR software, Ashland) that was precalibrated at 0, 1, 2, 3, and 4 Gray, and with the X-ray system built-in functions. RESULTS: Radiation dose was lowest with the Allura Clarity system [average film dose 4.2±0.1 cGray, peak film dose 18.3±1.6 cGray, Air Kerma (AK) dose 0.310±0.002 Gray, Dose Area Product (DAP) dose 23.72±0.84 Gray*cm2], intermediate with the Integris Allura FD20 (average film dose 4.4±1.1 cGray, peak film dose 29.4±15.5 cGray, AK 0.482±0.189 Gray, DAP 45.18±21.90 Gray*cm2), and highest with the Artis one system (average film dose 7.4±0.8 cGray, peak film dose 66.9±0.09 cGray, AK 0.746±0.085 Gray, DAP 75.93±9.11 Gray*cm2) and the Innova IGS system (average film dose 7.2±1.0 cGray, peak film dose 49.3±28.9 cGray, AK 0.874±0.340 Gray, DAP 92.28±14.73 Gray*cm2; P=0.011 for average film dose, P=0.019 for maximum film dose, P=0.033 for AK, and P=0.008 for DAP). CONCLUSIONS: The X-ray system type has significant impact on patient radiation dose during cardiac catheterization.

Contemporary use of embolic protection devices in saphenous vein graft interventions: Insights from the stenting of saphenous vein grafts trial.

BACKGROUND: We sought to evaluate the contemporary use of embolic protection devices (EPDs) in saphenous vein graft (SVG) interventions. METHODS: We examined EPD use in the stenting of saphenous vein grafts (SOS) trial, in which 80 patients with 112 lesions in 88 SVGs were randomized to a bare metal stent (39 patients, 43 grafts, and 55 lesions) or paclitaxel-eluting stent (41 patients, 45 grafts, and 57 lesions). RESULTS: An EPD was used in 60 of 112 lesions (54%). A Filterwire (Boston Scientific) was used in 70% of EPD-treated lesions, Spider (ev3, Plymouth, Minnesota) in 12%, Proxis (St. Jude, Minneapolis, Minnesota) in 12%, and Guardwire (Medtronic, Santa Rosa, California) in 7%. Of the remaining 52 lesions, an EPD was not utilized in 13 lesions (25%) because the lesion was near the distal anastomosis, in 14 lesions (27%) because of an ostial location, in one lesion (2%) because of small SVG size, in two in-stent restenosis lesions (4%) because of low distal embolization risk, and in 22 lesions (42%) because of operator's preference even though use of an EPD was feasible. Procedural success was achieved in 77 patients (96%); in one patient a Filterwire was entrapped requiring emergency coronary bypass graft surgery and two patients had acute stent thrombosis. CONCLUSION: In spite of their proven efficacy, EPDs were utilized in approximately half of SVG interventions in the SOS trial. Availability of a proximal protection device could allow protection of approximately 25% of unprotected lesions, yet operator discretion appears to be the major determinant of EPD use.

Optical coherence tomography findings after chronic total occlusion interventions: Insights from the "AngiographiC evaluation of the everolimus-eluting stent in chronic Total occlusions" (ACE-CTO) study (NCT01012869).

BACKGROUND: There is limited information on optical coherence tomography (OCT) findings after percutaneous coronary intervention (PCI) of chronic total occlusions (CTOs). OCT allows high resolution imaging that can enhance understanding of the vascular response after stenting of chronically occluded vessels. METHODS: The Angiographic Evaluation of the Everolimus-Eluting Stent in Chronic Total Occlusions (ACE-CTO) study collected angiographic and clinical outcomes from 100 patients undergoing CTO PCI with the everolimus-eluting stent (EES). OCT was performed 8-months post stenting in 62 patients. Every third frame was analyzed throughout the course of the stented arterial segment. Lumen contours were semi-automatically traced and stent struts were manually delineated, with automatic measurement of the strut to lumen distance. Struts on the luminal side of the lumen contour were classified as malapposed if the distance to the lumen contour exceeded 0.108mm. RESULTS: A total of 44,450 struts in 6047 frames were analyzed, of which 4113 9.3%, 95% confidence intervals [CI] 9.0% to 9.5%) were malapposed and 1230 (2.8%, 95% CI 2.6% to 2.9%) were uncovered. Fifty-five of 62 patients (88.7%, 95% CI 78.5% to 98.4%) had at least one malapposed stent strut and 50 patients (80.7%, 95% CI 69.2% to 88.6%) had at least one uncovered stent strut. Mean strut-intimal thickness of the apposed and malapposed struts was 0.126±0.140mm and -0.491±0.440mm, respectively. CONCLUSION: High rates of stent strut malapposition and incomplete stent strut coverage were observed after CTO PCI using EES, highlighting unique challenges associated with stent implantation in CTOs.

The AngiographiC Evaluation of the Everolimus-Eluting Stent in Chronic Total Occlusion (ACE-CTO) Study.

BACKGROUND: There are limited data on outcomes after implantation of second-generation drug-eluting stents in coronary chronic total occlusions (CTOs). We aimed to evaluate the frequency of angiographic restenosis and clinical outcomes after implantation of the everolimus-eluting stent (EES) in coronary CTOs. METHODS: One hundred patients undergoing successful CTO percutaneous coronary intervention using EES at our institution between 2009 and 2012 were enrolled. The primary study endpoint was binary in-segment restenosis at 8-month follow-up quantitative coronary angiography. Secondary endpoints included death, myocardial infarction, target-lesion and target-vessel revascularization, and symptom improvement. RESULTS: Mean age was 64 ± 7 years and 99% of the patients were men. The successful crossing technique was antegrade wiring in 51 patients, antegrade dissection/reentry in 24 patients, and retrograde in 25 patients. Binary angiographic restenosis occurred in 46% of the patients (95% confidence interval [CI], 35%-57%). The pattern of restenosis was focal, proliferative, and total occlusion in 19 lesions (46%), 14 lesions (34%), and 8 lesions (20%), respectively. At 12 months, the incidences of death, myocardial infarction, target-lesion revascularization, and target-vessel revascularization were 2%, 2%, 37%, and 39%, respectively. At 12 months, symptoms were improved, unchanged, or worse compared with baseline in 89 patients, 8 patients, and 1 patient, respectively (2 patients died before the 12-month follow-up). On multivariable analysis, smaller stent diameter was associated with higher risk for binary angiographic restenosis. CONCLUSION: High rates of angiographic restenosis and repeat revascularization were observed among patients receiving EES in coronary CTOs, but most had significant symptom improvement.

Effect of a real-time radiation monitoring device on operator radiation exposure during cardiac catheterization: the radiation reduction during cardiac catheterization using real-time monitoring study.

BACKGROUND: The Radiation Reduction During Cardiac Catheterization Using Real-Time Monitoring study sought to examine the effect of a radiation detection device that provides real-time operator dose reporting through auditory feedback (Bleeper Sv; Vertec Scientific Ltd; Berkshire, UK) on patient dose and operator exposure during cardiac catheterization. METHODS AND RESULTS: Between January 2012 and May 2014, 505 patients undergoing coronary angiography, percutaneous coronary intervention, or both were randomized to use (n=253) or no use (n=252) of the Bleeper Sv radiation monitor. Operator radiation exposure was measured in both groups using a second, silent radiation exposure monitoring device. Mean patient age was 65±8 years, most patients (99%) were men, and 30% had prior coronary artery bypass graft surgery. Baseline clinical characteristics were similar in the 2 study groups. Radial access was used in 18% and chronic total occlusion percutaneous coronary intervention constituted 7% of the total procedures. Median procedure time was 17 (12-27) minutes for diagnostic angiography, 42 (28-70) minutes for percutaneous coronary intervention, and 27 (14-51) minutes in the overall study population, with similar distribution between the study groups. First (9 [4-17] versus 14 [7-25] µSv; P<0.001) and second (5 [2-10] versus 7 [4-14] µSv; P<0.001) operator radiation exposure was significantly lower in the Bleeper Sv group. Use of the device did not result in a significant reduction in patient radiation dose. The effect of the Bleeper Sv device on operator radiation exposure was consistent among various study subgroups. CONCLUSIONS: Use of a real-time radiation monitoring device that provides auditory feedback can significantly reduce operator radiation exposure during cardiac catheterization. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT01510353.

Prevalence and outcomes of intermediate saphenous vein graft lesions: findings from the stenting of saphenous vein grafts randomized-controlled trial.

BACKGROUND: We sought to examine the prevalence and progression rate of intermediate saphenous vein graft (SVG) lesions in the Stenting Of Saphenous vein grafts (SOS) trial. METHODS: The baseline and follow-up angiograms of 80 patients participating in the SOS trial were analyzed to determine the prevalence of intermediate (30-60% angiographic diameter stenosis) SVG lesions and their progression rate. RESULTS: At least one intermediate SVG lesion was present in 31 of 143 (22%) SVGs in 27 of 80 (34%) patients. Most intermediate lesions were present in the SOS stented SVGs (20 grafts in 19 patients). During a median follow-up of 35 months, angiographic follow-up was available for 28 grafts in 25 patients. Progression (defined as percent diameter stenosis ≥ 70% but <100% at follow-up angiography) was seen in 11 of 28 SVGs (39%) in 11 of 25 patients (44%). Progression rate at 12, 24 and 36 months was 28% and 47% and 84%, respectively. Seven of 11 patients (64%) with intermediate SVG lesion progression presented with an acute coronary syndrome and 8 (73%) underwent PCI. Four of the 28 grafts with intermediate lesions at baseline were 100% occluded at follow-up; all of those SVGs had received a stent in another location in the SVG as part of the SOS trial. CONCLUSIONS: Intermediate SVG lesions are common in patients undergoing SVG stenting, have high rates of progression and frequently present with an acute coronary syndrome. Further study of pharmacologic and mechanical treatments to prevent progression of these lesions is needed.

Optical coherence tomography analysis of the stenting of saphenous vein graft (SOS) Xience V Study: use of the everolimus-eluting stent in saphenous vein graft lesions.

OBJECTIVES: The Stenting of Saphenous Grafts-Xience V (SOS-Xience V) trial prospectively examined the frequency of angiographic in-stent restenosis in saphenous vein graft (SVG) lesions 12 months after implantation of a Xience V everolimus-eluting stent (EES; Abbott Vascular). Optical coherence tomography (OCT) during follow-up angiography was added to the protocol after OCT was approved for clinical use in the United States. METHODS: Forty patients with 40 SVG lesions were enrolled in the study, of whom 27 underwent 12-month coronary angiography and 12 (only 1 of whom had in-stent restenosis) also had follow-up OCT evaluation. OCT strut-level analysis was performed to determine the percentage of strut coverage, malapposition, strut protrusion, neointimal thickness, and the existence of thrombus. RESULTS: Mean patient age was 67 ± 7 years, and 95% were men. A total of 2584 struts were evaluated by OCT. The percentages for uncovered, malapposed, and protruding struts were 4%, 9%, and 15%, respectively. The mean strut neointimal thickness was 0.094 ± 0.094 mm. Of the 12 stents analyzed, 4 (33%) showed full neointimal coverage, 2 (17%) had all the struts embedded, 7 (58%) had at least 1 malapposed strut, and 10 (83%) had at least 1 protruding strut. The mean difference between the stent area and the lumen area was 0.36 ± 1.6 mm². No thrombus was detected in the stented areas. CONCLUSIONS: Use of EES in SVGs is associated with high rates of stent strut coverage and high malapposition rates at 12 months post implantation.

Recurrent cardiovascular events with paclitaxel-eluting versus bare-metal stents in saphenous vein graft lesions: insights from the SOS (Stenting of Saphenous Vein Grafts) trial.

UNLABELLED: The Stenting of Saphenous Vein Grafts (SOS) trial demonstrated a reduction in clinical and angiographic adverse events with paclitaxel-eluting stents (PES) compared to bare-metal stents (BMS) in saphenous vein graft (SVG) lesions, but the rate of recurrent adverse events has not been described. METHODS: We performed a post hoc, landmark analysis to evaluate the risk of event recurrence following a non-fatal initial event among the SOS trial patients (pts). RESULTS: During a median follow-up of 35 months, the 80 pts enrolled in SOS experienced a total of 78 major cardiovascular events (MACE): 51 in the BMS group and 27 in PES group. No MACE were found in 28 pts (35%) while 52 pts (65%) had at least one event. The initial event was death in 13 pts (16%). Among the 39 pts whose initial event was not fatal, 12 (31%) had one or more subsequent MACE (50% of which were definitely related to the study SVG). The mean and median number of MACE per patient was significantly higher in patients receiving BMS versus PES (1.3 ± 1.2 and 1 ± 1.26 versus 0.6 ± 0.7 and 1 ± 0.825, p = 0.005 and p = 0.008, respectively). The rate of a second MACE following an initial event was 17% in the PES group and 37% in the BMS group (p = 0.24). Ten of 12 pts with recurrent events had received a BMS (83%). CONCLUSION: Pts undergoing SVG stenting had a high rate of recurrent events after an initial non-fatal event. These events were often related to the target vessel and most occurred in pts who had received a BMS, further supporting the benefit of PES over BMS in SVG lesions.

Continued benefit from paclitaxel-eluting compared with bare-metal stent implantation in saphenous vein graft lesions during long-term follow-up of the SOS (Stenting of Saphenous Vein Grafts) trial.

OBJECTIVES: This study sought to report the long-term outcomes after drug-eluting stent (DES) implantation in saphenous vein graft (SVG) lesions in the SOS (Stenting of Saphenous Vein Grafts) trial. BACKGROUND: The long-term outcomes after DES implantation in SVGs are poorly studied. Apart from the SOS trial, the only other randomized trial comparing DES with bare-metal stents (BMS) in SVGs reported higher mortality in the DES group at 32 months. METHODS: In the SOS trial, 80 patients with 112 lesions in 88 SVGs were randomized to a BMS or paclitaxel-eluting stent (PES) and demonstrated improved short-term angiographic and clinical outcomes with PES. Extended clinical follow-up was subsequently obtained. RESULTS: Mean age was 67 ± 9 years, and all patients were men. The indications for stenting included acute coronary syndrome in 60% and stable angina in 31% of patients. The mean SVG age was 12 ± 6 years. The baseline characteristics of the patients in the 2 study groups were similar. Procedural success was achieved in 77 patients (96%). During a median follow-up of 35 months, compared with patients randomized to BMS, those receiving PES had a lower incidence of myocardial infarction (hazard ratio [HR]: 0.32, p = 0.01), target lesion revascularization (HR: 0.20, p = 0.004), target vessel revascularization (HR: 0.41, p = 0.03), and target vessel failure (HR: 0.34, p = 0.001) as well as a trend toward less definite or probable stent thrombosis (HR: 0.15, p = 0.08). All-cause mortality (HR: 2.04, p = 0.19) and cardiac mortality (HR: 0.62, p = 0.51) did not differ between groups. CONCLUSIONS: During long-term follow-up, use of PES was associated with significantly better clinical outcomes than BMS in SVG lesions. (Stenting of Saphenous Vein Grafts Trial [SOS]; NCT00247208).

Paclitaxel-eluting stents reduce neointimal hyperplasia compared to bare metal stents in saphenous vein grafts: intravascular ultrasonography analysis of the SOS (Stenting of Saphenous Vein Grafts) trial.

AIMS: To compare the intravascular ultrasonography (IVUS) findings between saphenous vein grafts (SVG) treated with paclitaxel-eluting stents (PES) vs. bare metal stents (BMS) in the Stenting Of Saphenous Vein Grafts (SOS) trial. METHODS AND RESULTS: Of the 80 SOS trial patients, 38 had both baseline and follow-up IVUS examination and were included in this substudy: 17 patients received 28 BMS in 26 lesions and 21 patients received 30 PES in 28 lesions. Quantitative IVUS analysis was performed to determine the volume of in-stent neointimal hyperplasia (NIH) - defined as the difference between stent volume and lumen volume in the stented segments. Baseline characteristics were similar between patients who did and did not undergo baseline and follow-up IVUS. Patients receiving BMS and PES had similar stent and lumen volumes immediately after stenting. At 12-month follow-up, compared to BMS, PES-treated lesions had significantly less NIH volume (3.4 vs. 21.9 mm³, p<0.001) and neointima hyperplasia progression (1.6 vs. 17.1 mm³, p<0.001). No significant differences were seen in the 5 mm segment proximal and distal to the stent. CONCLUSIONS: Compared to BMS, use of PES in SVG lesions is associated with significantly lower NIH formation, which may help explain the improved clinical outcomes with PES in these lesions.

A randomized controlled trial of a paclitaxel-eluting stent versus a similar bare-metal stent in saphenous vein graft lesions the SOS (Stenting of Saphenous Vein Grafts) trial.

OBJECTIVES: The aim of this study was to compare the frequency of angiographic restenosis and clinical events between a paclitaxel-eluting stent (PES) and a similar bare-metal stent (BMS) in saphenous vein graft (SVG) lesions. BACKGROUND: There are conflicting and mostly retrospective data on outcomes after drug-eluting stent implantation in SVGs. METHODS: Patients requiring SVG lesion stenting were randomized to BMS or PES. The primary study end point was binary in-segment restenosis at 12-month follow-up quantitative coronary angiography. Secondary end points included death, myocardial infarction, ischemia-driven target vessel and lesion revascularization, and target vessel failure. RESULTS: Eighty patients with 112 lesions in 88 SVGs were randomized to a BMS (39 patients, 43 grafts, 55 lesions) or PES (41 patients, 45 grafts, 57 lesions). Binary angiographic restenosis occurred in 51% of the BMS-treated lesions versus 9% of the PES-treated lesions (relative risk: 0.18; 95% confidence interval [CI]: 0.07 to 0.48, p < 0.0001). During a median follow-up of 1.5 years the PES patients had less target lesion revascularization (28% vs. 5%, hazard ratio: 0.38; 95% CI: 0.15 to 0.74, p = 0.003) and target vessel failure (46% vs. 22%, hazard ratio: 0.65; 95% CI: 0.42 to 0.96, p = 0.03), a trend toward less target vessel revascularization (31% vs. 15%, hazard ratio: 0.66; 95% CI: 0.39 to 1.05, p = 0.08) and myocardial infarction (31% vs. 15%, hazard ratio: 0.67; 95% CI: 0.40 to 1.08, p = 0.10), and similar mortality (5% vs. 12%, hazard ratio: 1.56; 95% CI: 0.72 to 4.11, p = 0.27). CONCLUSIONS: In SVG lesions, PES are associated with lower rates of angiographic restenosis and target vessel failure than BMS.

Clinical presentation and angiographic characteristics of saphenous vein graft failure after stenting: insights from the SOS (stenting of saphenous vein grafts) trial.

OBJECTIVES: We sought to compare the clinical presentation and angiographic patterns of saphenous vein graft (SVG) failure after stenting with a paclitaxel-eluting stent (PES) versus a similar bare-metal stent (BMS). BACKGROUND: The mode of SVG failure after stenting has been poorly characterized. METHODS: The SOS (Stenting Of Saphenous Vein Grafts) trial enrolled 80 patients with 112 lesions in 88 SVGs who were randomized to a BMS or PES. Angiographic follow-up at 12 months was available in 83% of the patients. RESULTS: Binary angiographic restenosis occurred in 51% (24 of 47) of BMS-treated lesions versus 9% (4 of 43) of PES-treated lesions (p < 0.0001). Graft occlusion occurred in 9 of the 21 SVGs (43%) that failed in the BMS group and in 2 of 4 SVGs (50%) that failed in the PES group. SVG failure after stenting presented as an acute coronary syndrome in 10 of the 24 patients (42%) (7 of those 10 patients presented with non-ST-segment elevation acute myocardial infarction), stable angina in 9 (37%) patients, and without symptoms in 5 (21%) patients. Of the 19 patients (with 20 grafts) who developed symptomatic graft failure, repeat SVG revascularization was successfully performed in all 13 (100%) subtotally obstructed SVGs but was attempted (and successful) in only 1 of 7 (14%) occluded SVGs. Revascularization of a native coronary artery was performed in an additional 4 of 7 (57%) symptomatic patients with an occluded SVG. CONCLUSIONS: SVG failure after stenting often presents as acute myocardial infarction and with SVG occlusion. Compared with BMS, PES reduce SVG failure.