Reduced radiation exposure in the cardiac catheterization laboratory with a novel vertical radiation shield.

OBJECTIVES: Investigation of novel vertical radiation shield (VRS) in reducing operator radiation exposure. BACKGROUND: Radiation exposure to the operator remains an occupational health hazard in the cardiac catheterization laboratory (CCL). METHODS: A mannequin simulating an operator was placed near a computational phantom, simulating a patient. Measurement of dose equivalent and Air Kerma located the angle with the highest radiation, followed by a common magnification (8 in.) and comparison of horizontal radiation absorbing pads (HRAP) with or without VRS with two different: CCL, phantoms, and dosimeters. Physician exposure was subsequently measured prospectively with or without VRS during clinical procedures. RESULTS: Dose equivalent and Air Kerma to the mannequin was highest at left anterior oblique (LAO)-caudal angle (p < .005). Eight-inch magnification increased mGray by 86.5% and µSv/min by 12.2% compared to 10-in. (p < .005). Moving 40 cm from the access site lowered µSv/min by 30% (p < .005). With LAO-caudal angle and 8-in. magnification, VRS reduced µSv/min by 59%, (p < .005) in one CCL and µSv by 100% (p = .016) in second CCL in addition to HRAP. Prospective study of 177 procedures with HRAP, found VRS lowered µSv by 41.9% (µSv: 15.2 ± 13.4 vs. 26.2 ± 31.4, p = .001) with no difference in mGray. The difference was significant after multivariate adjustment for specified variables (p < .001). CONCLUSIONS: Operator radiation exposure is significantly reduced utilizing a novel VRS, HRAP, and distance from the X-ray tube, and consideration of lower magnification and avoiding LAO-caudal angles to lower radiation for both operator and patient.

Localization of culprit lesions in coronary arteries of patients with ST-segment elevation myocardial infarctions: relation to bifurcations and curvatures.

BACKGROUND: Although culprit lesions in ST-segment elevation myocardial infarction (STEMI) cluster in the proximal coronary arteries, their relationship to bifurcations and curvatures, where blood flow is disturbed, is unknown. We hypothesized that (a) culprit lesions localize to disturbed flow distal to bifurcations and curvatures and (b) the distribution of culprit lesions in the left (LCA) and right coronary arteries (RCA) and resulting infarct size are related to the location of bifurcations and curvatures. METHODS: Emory University's contribution to the National Cardiovascular Data Registry was queried for STEMIs. Using quantitative coronary angiography, the distances from the vessel ostium, major bifurcations, and major curvatures to the culprit lesion were measured in 385 patients. RESULTS: Culprit lesions were located within 20 mm of a bifurcation in 79% of patients and closer to the bifurcation in the LCA compared with the RCA (7.4 ± 7.3 vs 17.7 ± 14.8 mm, P < .0001). Of RCA culprit lesions, 45% were located within 20 mm of a major curvature. Compared with those in the RCA, culprit lesions in the LCA were located more proximally (24.4 ± 16.5 vs 44.7 ± 28.8 mm, P = .0003) and were associated with larger myocardial infarctions as assessed by peak creatine kinase-MB (208 ± 222 vs 140 ± 153 ng/dL, P = .001) and troponin I (59 ± 62 vs 40 ± 35 ng/dL, P = .0006) and with higher in-hospital mortality (5.2% vs 1.1%, P = .04). CONCLUSIONS: In patients with STEMI, culprit lesions are frequently located immediately distal to bifurcations and in proximity to major curvatures where disturbed flow is known to occur. This supports the role of wall shear stress in the pathogenesis of STEMI.

Variation in physician deep vein thrombosis prophylaxis attitudes and practices at an academic tertiary care center.

BACKGROUND: Deep vein thrombosis (DVT) remains a major cause of in-hospital morbidity and mortality. Effective DVT prophylaxis is available but underutilized. We sought to describe physician understanding of DVT epidemiology and prophylaxis practices. METHODS: All medical and surgical residents, and hospitalist attendings were invited to participate in an on-line survey. Physicians were queried about DVT epidemiology, risk factors, prophylaxis practices, and complications. Means and standard deviations were calculated for ordinal responses. χ² was used for dichotomous variables. RESULTS: Of 281 doctors emailed, 69/160 (43%) medical residents, 26/72 (36%) surgical residents, and 21/49 (43%) hospitalist attendings participated. All three overestimated DVT incidence and morbidity. Surgical residents listed paralysis as high risk and minor surgery as a low/no risk factor. Medical residents thought heart failure and varicose veins were low/no risk for developing DVT. Regarding prophylaxis, surgical residents did not identify ambulation as a prophylactic measure, and were more likely to use SCDs, compression stockings, and enoxaparin, while medical residents and hospitalist attendings prescribed unfractionated heparin most frequently. Medical residents reported that they would hold anticoagulants for comorbidities most frequently, but all 3 groups agreed that anticoagulant prophylaxis would not significantly increase bleeding risks. CONCLUSIONS: Perceptions of DVT risk factors and prophylaxis practices vary by both physician specialty and attending/resident status. Prophylaxis practice differences may result from these perceptions.

Effects of a refugee elective on medical student perceptions.

BACKGROUND: There are growing numbers of refugees throughout the world. Refugee health is a relatively unstudied and rarely taught component of medical education. In response to this need, a Refugee Health Elective was begun. Medical student perceptions toward cultural aspects of medicine and refugee health before and after participation in the elective were measured. METHODS: Preliminary questionnaires were given to all preclinical students at the academic year commencement with follow-up questionnaires at the refugee elective's conclusion. Both questionnaires examined students' comfort in interacting with patients and familiarity with refugee medical issues, alternative medical practices, and social hindrances to medical care. The preliminary answers served as a control and follow-up questionnaire data were separated into participant/non-participant categories. All preclinical medical students at two Midwestern medical schools were provided the opportunity to participate in the Refugee Health Elective and surveys. The 3 data groups were compared using unadjusted and adjusted analysis techniques with the Kruskall-Wallis, Bonferroni and ANCOVA adjustment. P-values < 0.05 were considered significant. RESULTS: 408 and 403 students filled out the preliminary and follow-up questionnaires, respectfully, 42 of whom participated in the elective. Students considering themselves minorities or multilingual were more likely to participate. Elective participants were more likely to be able to recognize the medical/mental health issues common to refugees, to feel comfortable interacting with foreign-born patients, and to identify cultural differences in understanding medical/mental health conditions, after adjusting for minority or multilingual status. CONCLUSION: As medical schools integrate a more multicultural curriculum, a Refugee Health Elective for preclinical students can enhance awareness and promote change in attitude toward medical/mental health issues common to refugees. This elective format offers tangible and effective avenues for these topics to be addressed.

Use of the stingray re-entry system in two complex cases of occluded superficial femoral arteries.

Totally occluded infrainguinal arterial disease presents formidable challenges to endovascular revascularization. A variety of devices have been made available to make the crossing of these lesions more amenable to endovascular techniques. We discuss the novel use of a device that has been developed for crossing occluded coronary arteries, the Stingray Re-Entry System.

Women and heart disease: knowledge, worry, and motivation.

BACKGROUND: Heart disease remains the number one killer of women. Epidemiologic data show a persisting failure to raise the perception of heart disease risk in women despite massive campaigning efforts. We sought to describe the psychosocial barriers preventing women from recognizing this risk and actively preventing heart disease. METHODS: We obtained access to data from the 534 participants of a random sampling of U.S. women from a commercial telephone survey commissioned by a nonprofit advocacy organization, the Society for Women's Health Research, in 2007. The survey was designed to test women's general knowledge of cardiac risk factors. We grouped the questions into five psychosocial/knowledge categories: worry, motivation, personal cardiovascular risk awareness, general cardiac knowledge, and general cholesterol knowledge. Univariate and multivariate modeling of the relationships of these psychosocial/knowledge categories-along with five baseline demographic variables, age, ethnicity, income, education, and geographic location-to the motivation score were performed. RESULTS: Univariate modeling revealed that higher motivation scores were associated with greater personal risk factor knowledge/awareness and more worry about cardiovascular disease (CVD) (R(2)=0.43, 95% confidence interval [CI] 0.35-0.50 for both scores). Younger age, Asian ethnicity, and lower education levels were associated with less motivation to modify their cardiovascular risk factors (p<0.05). Multivariate modeling revealed a persistent significant relationship of motivation to worry, personal cardiovascular risk awareness, age <45 years, and nonblack, non-Hispanic ethnic minority (p<0.001). CONCLUSIONS: Worried and knowledgeable women over the age of 45 are motivated to modify their risk factors. Heart health education targeting the subgroups of less motivated women may be of benefit to raise awareness of heart disease.

Comparison of location of "culprit lesions" in left anterior descending coronary artery among patients with anterior wall ST-segment elevation myocardial infarction having ramus intermedius coronary arteries versus patients not having such arteries.

Disturbed, nonlaminar flow distal to arterial bifurcations contributes to atherosclerosis development and progression. We hypothesized that the presence of a ramus intermedius (RI) amplifies the flow disturbances in the proximal left anterior descending (LAD) artery causing more proximal LAD lesions and larger ST-segment elevation myocardial infarction (STEMI). Emory University's contribution to the National Cardiovascular Data Registry was queried for STEMIs from January 2006 to July 2008. The distance from the LAD ostium to the lesion was measured in patients with angiographically visible culprit lesions. The peak troponin-I, creatinine kinase-MB, and left ventricular ejection fraction were used as markers for infarct size. Of the 386 patients with STEMI, 150 had LAD culprit lesions. The mean lesion distance from the LAD ostium was 15.2 +/- 11.0 mm in the patients with RI (n = 44) and 29 +/- 19 mm in those without RI (n = 106; p <0.01). LAD lesions were more proximal in the patients with RI, with 43% and 63% of lesions occurring in the first 10 and 20 mm of the LAD, respectively, versus 10% and 32% in those without RI (p <0.01). Patients with RI had greater peak troponin-I (69 +/- 40 ng/ml vs 50 +/- 39 ng/ml, p = 0.01) and peak creatinine kinase-MB (277 +/- 271 ng/ml vs 174 +/- 190 ng/ml, p = 0.01). A trend was seen toward a lower left ventricular ejection fraction in patients with RI (36 +/- 10% versus 40 +/- 11%, p = 0.06). In conclusion, the presence of RI was associated with more proximal LAD lesions and larger anterior infarctions, suggesting anatomy-induced flow disturbances have important clinical implications.