Dramatic loss of inorganic carbon by nitrogen-induced soil acidification in Chinese croplands

Intensive crop production systems worldwide, particularly in China, rely heavily on nitrogen (N) fertilization, but left more than 50% of fertilizer N in the environment. Nitrogen (over) fertilization and atmospheric N deposition induce soil acidification, which is neutralized by soil inorganic carbon (SIC; carbonates), and carbon dioxide (CO₂ ) is released to the atmosphere. For the first time, the loss of SIC stocks in response to N-induced soil acidification was estimated for Chinese croplands from 1980 to 2020 and forecasts were made up to 2100. The SIC stocks in croplands in 1980 were 2.16 Pg C (16.3 Mg C/ha) in the upper 40 cm, 7% (0.15 Pg C; 1.1 Mg C/ha) of which were lost from 1980 to 2020. During these 40 years, 7 million ha of cropland has become carbonate free. Another 37% of the SIC stocks may be lost up to 2100 in China, leaving 30 million ha of cropland (37.8%) without carbonates if N fertilization follows the business-as-usual (BAU) scenario. Compared to the BAU scenario, the reduction in N input by 15%-30% after 2020 (scenarios S1 and S2) will decrease carbonate dissolution by 18%-41%. If N input remains constant as noted in 2020 (S3) or decreases by 1% annually (S4), a reduction of up to 52%-67% in carbonate dissolution is expected compared to the BAU scenario. The presence of CaCO₃ in the soil is important for various processes including acidity buffering, aggregate formation and stabilization, organic matter stabilization, microbial and enzyme activities, nutrient cycling and availability, and water permeability and plant productivity. Therefore, optimizing N fertilization and improving N-use efficiency are important for decreasing SIC losses from acidification. N application should be strictly calculated based on crop demand, and any overfertilization should be avoided to prevent environmental problems and soil fertility decline associated with CaCO₃ losses.

Generation of low-symmetry perovskite structures forab initiocomputation

Ion displacements are the fundamental cause of ferroelectricity in perovskites. By properly shifting ions,ab initiocomputations have been extensively used to investigate the properties of perovskites in various structural phases. In addition to the relatively simple ion displacements, perovskites have another type of structural distortion known as antiferrodistortion or oxygen octahedron tilting. The interplay between these two types of distortions have generated abundant structural phases that can be tedious to prepare forab initiocomputation, especially for large supercells. Here, we design and implement a computer program to facilitate the generation of distorted perovskite structures, which can be readily used forab initiocomputation to gain further insight into the perovskite of a given structural phase.

Abstract 356: Hospital Safety Net Status and Clinical Outcomes After Trans-catheter Aortic Valve Replacement

Introduction: Safety-net hospitals (SNH) treat a large population of un-insured and low income patients; several prior studies report worse outcome at these centers. Trans-catheter valve replacement (TAVR) is emerging as first-line therapy for aortic stenosis irrespective of surgical risk scores. However, results of TAVR performed at these centers is limited.

Objective: To determine whether post-procedural outcomes of TAVR are comparable at safety-net (SNH) and non-safety net hospitals (non-SNH).

Methods: We conducted a retrospective, cohort study with propensity-matched analysis. Complex survey data from the Agency for Healthcare Quality and Research containing weighted sample of all hospital admissions nationwide was utilized for this study. Adults undergoing TAVR at US hospitals participating in the National In-patient sample (NIS) database from January 2014 - December 2015 were included. A 1:1 propensity-matched cohort of patients operated at safety-net hospitals (SNH) and non-SNH institutions was analyzed. Propensity-matching was performed on the basis of sixteen demographic and clinical confounding co-variates. Main outcome studied was all-cause post-procedural mortality. Secondary outcomes compared were stroke, acute kidney injury and length of post-operative stay.

Results: Between 2014 - 2015, 41410 patients (mean age 80 +/- 0.11 years, 46% female) underwent TAVR at 731 centers nationwide; 6996 (16.80 %) procedures were performed at safety net centers. SNH comprised 135/731 (18.4%) of all centers performing TAVR. SNH patients were more likely to be female (49 % vs 46 %, p <0.001); admitted emergently (31% vs 21%; p <0.001) and at the lowest quartile for household income (25% % vs 20 %; p <0.001). A large proportion of SNH patients were minorities (Blacks 5.9% vs 3.9%; Hispanic 7.2% vs 3.2%). Adjusted logistic regression was performed on 6995 propensity-matched patient pairs. Post-procedural mortality [OR 0.99 (0.98 - 1.007); p = 0.43], stroke [OR 1.009 (0.99-1.02); p = 0.08], and acute kidney injury [OR 0.99 (0.96 - 1.01); p = 0.5] were comparable in both cohorts. Overall length of stay was also similar (6.9 +/- 0.1 vs 7.1 +/- 0.2 days; p = 057).

Conclusion: Post-procedural outcomes after TAVR at SNH are comparable to national outcomes. Our study provides preliminary evidence that wider adoption of TAVR may not adversely influence outcomes at SNH.

Abstract 107: Home Health Care After Discharge is Associated With Less Early Readmissions for Patients With Acute Myocardial Infarction

Objective: Home health care (HHC) is a support tool to transition patients after discharge and acute myocardial infarction (AMI) is a significant cause of morbidity and mortality in the U.S. However, little is known regarding the impact of HHC on AMI patients. We sought to identify predictors of readmissions among AMI patients, characteristics of those who receive HHC and investigate the association of HHC with readmission.

Methods: We queried the National Readmission Database (NRD) (January 2012 - December 2014), to identify patients discharged after AMI and selected patients who were discharged home with (HHC+) and without HHC (HHC-). We reported national estimates with survey methods with weights provided in our data. After univariate exploratory analyses, we developed a regression model to identify the probability of each patient to receive HHC. From the propensity score, we calculated average treatment on the treated (ATT) weights. These ATT weights were included in the logistic regression model to determine the impact of HHC on readmission after adjusting for available clinical confounders. We considered post-weighting standardized differences <10% as appropriate for our ATT model. To determine clinical factors associated with readmission, we also performed a multi-variable logistic regression with readmission as the end-point. All results were reported as risk ratios (RR) with their 95% confidence intervals (CI).

Results: Between January 2012 to December 2014, 406,237 patients were treated for AMI and discharged home with or without HHC. Among these 9.4% (38,215) received HHC. HHC+ patients were older (mean age 77 ± 11 vs 60 ±12 years p<0.001), more likely to be female (53.6% vs. 26.9%, p <0.001), and have cancer (3.7% vs 1.3%, p <0.001), congestive heart failure (5.7% vs. 0.5%, p <0.001), chronic pulmonary disease (23.2% vs. 12.7%, p <0.001), chronic kidney disease (26.9% vs 6.9%, p <0.001), diabetes (35.6% vs. 26.7%, p <0.001), hypertension (70.7% vs. 64.8%, p <0.001) and peripheral vascular disease (14.6% vs 6.4%, p <0.001). Patients readmitted after MI were more likely to be older and have diabetes (RR 1.42, 95% CI 1.37-1.48), CHF (RR 5.89, CI 5.55-6.26) or COPD (RR 1.59, 1.52-1.65). Unadjusted 30-day readmission rate was 20.9% for HHC+ and 8.2% for HHC- patients. Propensity-weighted adjustment for covariates yielded 36,979 HHC+ patients and 37,785 HHC- patients. Adjusted risk rations (RR) for 30-day readmission were computed using ATT weights, and HHC+ patients had significantly lower readmission risk (RR 0.89, 95% CI 0.82 - 0.96) compared to HHC- (RR 1.12, 95% CI 1.04 - 1.21; p < 0.001)

Conclusion: In the United States, a small proportion of patients receive home health care after discharge post-AMI. Older, females and those with diabetes or heart failure are more likely to receive home health care. Use of home health care may be associated with lower 30-day readmission rates after AMI.

Abstract 337: Gender Differences and Outcome After Isolated Coronary Artery Bypass Grafting: A Systematic Review and Meta-analysis

Background: Coronary artery bypass grafting (CABG) is among the most common surgical procedures performed in developed nations. In spite of this, studies have reported gender differences in clinical outcome exist in outcome after CABG. As data is limited to observational studies, we performed a systematic review to compare CABG outcome between women and men.

Methods: We queried databases (1 st January 2000 - 20 th January 2020) to identify original studies comparing CABG outcome between genders. Our aims were (1) to study differences in risk factors (2) to compare early mortality, stroke, wound infection, acute kidney injury rates and long-term survival. We pooled risk ratios (RR) with inverse variance weighting and a random effects model for early end-points. Long-term survival was compared using incident risk ratios (IRR). All results are presented with their 95% confidence interval.

Results: We identified 24 observational studies (1,647,035 women and 3,642,057 men) from 13 countries for inclusion. At time of CABG, women were older (66 vs 64 years; p < 0.01) and had a higher incidence of diabetes mellitus (32% vs 24%; p < 0.01), congestive heart failure (12% vs 8%; p < 0.01) and emergent surgery (13% vs 9%). More men had left ventricular dysfunction (12% vs 10%; p < 0.01) and prior myocardial infarction (40% vs 37%). Women received fewer grafts (mean difference -0.22; p < 0.01) and arterial conduits (OR 0.51, CI 0.41 - 0.63; p < 0.01). Early mortality (4% vs 2.5%, OR 1.5, CI 1.4 - 1.7) and stroke rates (OR 1.9, CI 1.3 - 1.7) were higher in women. Sternal wound infection (4.7% vs 2%) was also higher in women (OR 1.8, CI 1.1 - 1.8, p = 0.001). Acute kidney injury (OR 1.1, p = 0.09) and long-term survival (IRR 0.9, CI 0.8 - 1.2, p = 0.9) are comparable.

Conclusion: Our meta-analysis demonstrates that women and men have significant differences in presentation and outcome after CABG. While women have worse post-operative outcomes, long-term survival is comparable.

Home health care visits may reduce the need for early readmission after coronary artery bypass grafting

BACKGROUND

The Center for Medicaid and Medicare Services penalizes hospitals with high readmission rates after coronary artery bypass grafting (CABG). Home health care (HHC) is a proven discharge support tool. We performed a propensity-matched analysis to determine impact of HHC on readmissions after CABG.

METHODS

We queried the National Readmissions Database (January 2012-December 2014) for patients undergoing isolated CABG discharged home with and without HHC. Primary end point was 30-day readmission. A well-balanced subset of patients with and without HHC was created with propensity matching. Weight-adjusted logistic regression was performed to determine impact of HHC on readmissions after CABG.

RESULTS

In our study, 204,184 patients (mean age. 64 years; 22% female) were discharged home after CABG; 86,206 (42%) received HHC. Old age (66 vs 63 years; P < .01), diabetes (46% vs 41%; P < .001), COPD (21% vs 18%; P < .01), peripheral arterial disease (14% vs 11%; P < .001), and chronic kidney disease (2% vs 1.5%; P = .01) were factors associated with HHC. With nearest-neighbor 1:1 matching without replacement, we identified 66,610 patient pairs (unweighted) for further analysis. Readmission occurred in 11.1% and 12.5% of patients with and without HHC, respectively. After adjustment for 21 clinical covariates, use of HHC (odds ratio, 0.816; 95% confidence interval, 0.808-0.823) led to significantly lower readmission rates (P < .001).

CONCLUSIONS

HHC after coronary artery bypass surgery is more often provided to women, older patients, and those with diabetes mellitus, peripheral arterial disease, and chronic lung or kidney dysfunction. HHC appears to be associated with reduced rates of early readmission.

Healthcare Resource Use and Expenditures in Patients Newly Diagnosed With Paroxysmal Supraventricular Tachycardia

Information on paroxysmal supraventricular tachycardia (PSVT) patient characteristics and the associated economic burden of the disease is limited. Therefore, we sought to characterize newly diagnosed PSVT patients and quantify their healthcare resource use and expenditures. We used enrollment, demographic, and claims data from IBM MarketScan Research Database and Medicare Limited Data Set (LDS) to identify patients newly diagnosed with PSVT (ICD-9: 427.0; ICD-10: I47.1) from 10/1/2012 to 9/30/2016. Patients were required to be observable 1-year before and after index diagnosis. Patients were stratified by age (<65 years and ≥65 years), and propensity-matched to patients without PSVT. Expenditures and healthcare resource use were analyzed 1 year before and 1-year following index diagnosis. Among 49,316 patients <65 years and 23,954 patients ≥65 years, most were female (64% and 63%, respectively). Compared with matched controls, all PSVT patients had significantly more emergency department visits pre- and postdiagnosis, and more hospitalizations following diagnosis. Mean annual per patient expenditures paid by insurers were significantly higher in the year post-PSVT diagnosis, tripling for patients <65 years ($9,028 to $29,867) and nearly doubling for patients ≥65 years ($10,867 to $20,143). Spending for PSVT services accounted for 43% and 33% of the increase in expenditures in these patient-groups, respectively. Few patients had an ablation within 1 year of diagnosis, although ablations were more frequent in patients age <65 years (13% vs 3%). In conclusion, PSVT imposes a substantial economic burden, with increases in expenditures following initial diagnosis in both younger (<65 years) and older (≥65 years) patients who are not accounted for by cardiac ablation spending alone.

Probing optical resonances of silicon nanostructures using tunable-excitation Raman spectroscopy

Optical materials with a high refractive index enable effective manipulation of light at the nanoscale through strong light confinement. However, the optical near field, which is mainly confined inside such high-index nanostructures, is difficult to probe with existing measurement techniques. Here, we exploit the connection between Raman scattering and the stored electric energy to detect resonance-induced near-field enhancements in silicon nanostructures. We introduce a Raman setup with a wavelength-tunable laser, which allows us to tune the Raman excitation wavelength and thereby identify Fabry-Pérot and Mie type resonances in silicon thin films and nanodisk arrays, respectively. We measure the optical near-field enhancement by comparing the Raman response on and off resonance. Our results show that tunable-excitation Raman spectroscopy can be used as a complimentary far-field technique to reflection measurements for nanoscale characterization and quality control. As proof-of-principle for the latter, we demonstrate that Raman spectroscopy captures fabrication imperfections in the silicon nanodisk arrays, enabling an all-optical quality control of metasurfaces.

Can secondary metabolites extracted from Moringa seeds suppress ammonia oxidizers to increase nitrogen use efficiency and reduce nitrate contamination in potato tubers?

Nitrification inhibition as an alleviation tool to decrease nitrogen (N) losses and increase N use efficiency (NUE) as well as reducing NO₃^- accumulation in plants is a promising technology. No study thus far has directly or indirectly to use the secondary metabolites extracted from Moringa (Moringa oleifera Lam) seeds as nitrification inhibitors. Moringa seed extract (MSE) was studied based on its content of phenolic compounds (PC) and for its antioxidant characteristic. A 2-year field experiment and 30-day incubation experiment were conducted with three treatments of control (CK), N fertilizer (300 kg N ha^-1 and 200 mg N kg^-1 soil for the field and incubation experiment, respectively), and N fertilizer with MSE (500 ppm as a TPC) to investigate the responses of ammonia-oxidizing bacteria (AOB) and archaea (AOA) to MSE and the consequences for NUE and NO₃^- accumulation in potato tubers. Total phenolics amount was 144 mg gallic acid equivalent g^-1 MSE, while flavonoid contents were 76.6 quercetin equivalent g^-1 MSE. MSE showed antioxidant activity that was comparable to the standard antioxidants TBHQ and gallic acid. MSE application with N fertilizer retarded the nitrification process, as indicated by a higher NH₄⁺-N and lower NO₃^--N content, compared with N fertilizer application alone. NH₄⁺-N content reduced to initial CK level on Day 20 under N fertilizer application alone. However, NH₄⁺-N content decreased to initial control level on Day 30 when MSE was applied. The mechanisms resulted from curbing AOB growth by phenolic compounds (TPC, TF, TAC), leading to a delay in nitrification process. AOB increased significantly when N fertilizer was applied alone; on the contrary, AOA was not sensitive to N fertilizer (with and without MSE). Increase in NUE from 37.5% to 66.3% in potato plants under MSE application with N fertilizer was also observed compared with N fertilizer application alone. The highest NO₃^- accumulation (569 mg NO₃^- kg^-1) in tubers was recorded under N fertilizer application without MSE. MSE application significantly decreased NO₃^- accumulation (92 mg NO₃^- kg^-1) in tubers which is lower than the maximum value of accepting tubers (200 mg NO₃^- kg^-1). The highest average of N uptake, fresh and dry weight, carotenoids, chlorophyll a, chlorophyll b and nitrate reductase activity was recorded when MSE was applied with N fertilizer. Accordingly, using of Moringa extracted secondary metabolites to suppress AOB growth in the soil is a significant strategy to reduce nitrification rate and N loss from soils, and therefore increase NUE as well as reducing NO₃^- accumulation in potato tubers.

Role of Arbuscular Mycorrhizal Fungi in Plant Growth Regulation: Implications in Abiotic Stress Tolerance

Abiotic stresses hamper plant growth and productivity. Climate change and agricultural malpractices like excessive use of fertilizers and pesticides have aggravated the effects of abiotic stresses on crop productivity and degraded the ecosystem. There is an urgent need for environment-friendly management techniques such as the use of arbuscular mycorrhizal fungi (AMF) for enhancing crop productivity. AMF are commonly known as bio-fertilizers. Moreover, it is widely believed that the inoculation of AMF provides tolerance to host plants against various stressful situations like heat, salinity, drought, metals, and extreme temperatures. AMF may both assist host plants in the up-regulation of tolerance mechanisms and prevent the down-regulation of key metabolic pathways. AMF, being natural root symbionts, provide essential plant inorganic nutrients to host plants, thereby improving growth and yield under unstressed and stressed regimes. The role of AMF as a bio-fertilizer can potentially strengthen plants' adaptability to changing environment. Thus, further research focusing on the AMF-mediated promotion of crop quality and productivity is needed. The present review provides a comprehensive up-to-date knowledge on AMF and their influence on host plants at various growth stages, their advantages and applications, and consequently the importance of the relationships of different plant nutrients with AMF.

Budgeting nitrogen flows and the food nitrogen footprint of Egypt during the past half century: Challenges and opportunities

Egypt is the largest nitrogen (N) fertilizer consumer in Africa. However, its nitrogen use efficiency (NUE) is low, and the relationships between both dietary options and the NUE trend with reactive N (Nr) release into the environment in Egypt have not yet been studied. In this study, we estimated the changes in the N budget and NUE in Egypt during the past 56 years (1961-2016). We also calculated particular virtual N factors (the average amount of Nr released to the environment during food production per unit of N consumption) for major food items to estimate their N footprints (NF). The total N input to croplands increased from 136 kg N ha^-1 y^-1 (1961-1970) to 307 kg N ha^-1 y^-1 (2010-2016), while the total crop N uptake increased from 101 kg N ha^-1 y^-1 to 136 kg N ha^-1 y^-1, indicating a decrease of NUE from 71% (1960s) to 44% during 2010-2016. Gaseous N emissions of NH₃, N₂O, and NO increased from 97, 5.6, and 8.3 Gg N y^-1 to 339, 29, and 39 Gg N y^-1. The total per capita food NF increased from 15 kg N capita^-1 y^-1 (1961-1970) to 26 kg N capita^-1 y^-1 (2010-2016). There was a change in the average per capita food consumption NF and food production NF from the 1960s (3.2 and 11.3 kg capita^-1 y^-1) to 2010-2016 (5.9 and 20.3 kg N capita^-1 y^-1). There is a dire need to increase the NUE and decrease the food NF in Egypt to minimize the negative consequences of Nr on the environment.

Coronary Embolism: A Systematic Review

BACKGROUND

Coronary embolism is a rare and potentially fatal phenomenon that occurs primarily in patients with valvular heart disease and atrial fibrillation. There is a lack of consensus regarding the diagnosis, treatment, and management of coronary embolism, leaving management at the discretion of the treating physician. Through this review, we aim to establish a better understanding of coronary embolism, and to identify treatment options - invasive and non-invasive - that may be used to manage coronary embolism.

METHODS AND RESULTS

Our systematic review included 147 documented cases of coronary embolism from case reports and case series. The average age of our population was 54.2 ± 17.6 years. The most common causes of coronary embolism included infective endocarditis (22.4%), atrial fibrillation (17.0%), and prosthetic heart valve thrombosis (16.3%). Initial presentation was indistinguishable from an acute coronary syndrome (ACS) due to coronary atherosclerosis, and the diagnosis required a high level of suspicion and evaluation with angiography. Treatment strategies included, but were not limited to, thrombectomy, thrombolysis, balloon angioplasty and stent placement. Myocardial dysfunction on echocardiography was observed in over 80% of patients following coronary embolism. "Good outcomes" were reported in 68.7% of case reports and case series, with a mortality rate of 12.9%.

CONCLUSION

Coronary embolism is an under-recognized etiology of myocardial infarction with the potential for significant morbidity and mortality. To improve outcomes, physicians should strive for early diagnosis and intervention based on the underlying etiology. Thrombectomy may be considered with the goal of rapid restoration of coronary flow.

Stability After Initial Decline in Coronary Revascularization Rates in the United States

BACKGROUND

It remains uncertain how advances in revascularization techniques, availability of new evidence, and updated guidelines have influenced the annual rates of coronary revascularization in the United States.

METHODS

We used the Nationwide Inpatient Sample data from 2005 to 2014 with appropriate weighting to determine national procedural volumes. To present accurately overall percutaneous coronary intervention (PCI) rates, PCI with same-day discharge numbers per year were estimated from the available literature and added to annual PCI procedures performed.

RESULTS

Annual PCI rate declined from 353 per 100,000 adults in 2005 to 277 per 100,000 adults in 2009 (P < .001) but remained stable thereafter (P = .50). Annual coronary artery bypass grafting (CABG) rate declined steadily, at a shallower slope than PCI, from 120 per 100,000 in 2005 to 93 per 100,000 in 2009 (P = .02) but remained stable thereafter (P = .60). Similar trends were seen in men and women. Both PCI and CABG rates were lower in women than men over the study period (PCI, 482 to 324/100,000 in men vs 232 to 153/100,000 in women; CABG, 172 to 118/100,000 in men vs 64 to 38/100,000 in women). Annual PCI rates were higher than CABG rates in patients of all age groups including in younger patients (age < 50) and octogenarians. The proportion of coronary revascularization procedures performed per insurance type remained relatively similar across the study period.

CONCLUSIONS

Annual rates of coronary revascularization have changed significantly over time, potentially because of advances in revascularization techniques, availability of new evidence, and updated guidelines. Rates of PCI declined more steeply than CABG before plateauing but remained higher than rates of CABG across the study period.

Meta-Analysis Evaluating the Effect of Left Coronary Dominance on Outcomes After Percutaneous Coronary Intervention

Prognostic significance of coronary circulation dominance remains controversial. The primary objective of this meta-analysis was to pool all the available evidence to assess the influence of left coronary dominance (LD) on outcomes in patients who underwent percutaneous coronary intervention (PCI). MEDLINE, Cochrane CENTRAL, and Scopus databases were searched for all observational studies and randomized controlled trials that investigated the association between coronary dominance and outcomes in patients who underwent PCI. Odds ratios (OR) and 95% confidence intervals from individual studies were pooled using a random effects model. A total of nine studies including 266,119 patients were included. On pooled analysis, it was noted that LD was associated with significantly increased odds of in-hospital (OR: 1.54 [1.12, 2.11]; p = 0.007), 30-day (OR: 2.16 [1.22, 3.84]; p = 0.008), and long-term mortality (OR: 1.83 [1.33 to 2.50]; p < 0.001). LD patients also experienced a significantly higher incidence of major adverse cardiac events (OR: 1.27 [1.03, 1.58]; p = 0.03) and failed PCI (OR: 1.30 [1.03, 1.65]; p = 0.03). In contrast, no significant difference was noted between LD and non-LD patients in the incidence of stent thrombosis (OR: 1.28 [0.55, 3.01]; p = 0.57; I² = 0%) or reinfarction (OR: 1.73 [0.90, 3.35]; p = 0.10; I² = 63%). In conclusion, this meta-analysis suggests that patients with LD coronary anatomy are at significantly increased risk for mortality after PCI compared with patients with a non-LD anatomy.

Risk Calculator to Predict 30-Day Readmission After Coronary Artery Bypass: A Strategic Decision Support Tool

BACKGROUND

Re-admission is an important source of patient dissatisfaction and increased hospital costs. A simple calculator to determine the probability of re-admission may help guide patient dismissal planning.

METHODS

Using the national readmissions database (NRD), we identified admissions for isolated primary coronary artery bypass (CABG) and stratified them according to 30-day readmission. Including pre, intra and postoperative variables, we prepared a logistic regression model to determine the probability for re-admission. The model was tested for reliability with boot-strapping and 10-fold cross-validation.

RESULTS

From 135,699 procedures, 19,355 were readmitted at least once within 30days of dismissal. Patients who were readmitted were older (67±10 vs 65 ± 10 years, p<0.01), females (32% vs 24%; p<0.01) and had a higher Elixhauser comorbidity score (1.5±1.4 vs 1.1±1.2; p<0.01). Our final model (c- statistic=0.65) consisted of 16 pre and three postoperative factors. End-stage renal disease (OR 1.79 [1.57-2.04]) and length of stay>9days (OR 1.60 [1.52-1.68]) were most prominent indicators for readmission. Compared to Medicaid beneficiaries, those with private insurance (OR 0.62 [0.57-0.68]) and Medicare (OR 0.85 [0.79-0.92]) coverage were less likely to be readmitted.

CONCLUSIONS

Our simple 30-days CABG readmission calculator can be used as a strategic tool to help reduce readmissions after coronary artery bypass surgery.

Early Clinical Impact of Diagnostic Breast Ultrasound Performed by General Practitioners and Nurses in Rwanda

Background: Diagnostic breast ultrasound (US) could be an important tool for early detection of breast cancer in low-resource settings, where efficient strategies to refine the likelihood of malignancy among palpable breast masses are needed. However, the feasibility and clinical role of diagnostic ultrasound in such settings has not been described. We trained 4 general practitioner doctors (GPs) and 5 nurses in diagnostic breast US at a rural district hospital in Rwanda that serves as a cancer referral facility. Aim: Assess management plans, biopsy rates and patient diagnoses after nurse- and GP-performed breast ultrasounds to determine the impact of diagnostic US on clinical care. Methods: We reviewed outcomes from trainees' ultrasounds during 21 months of in-person and electronic training and mentorship by Boston-based radiologists. Trainees' US assessments and management plans were recorded on structured clinical forms. Patient diagnoses and follow-up were extracted from medical records using a standardized data collection form. Among patients who received breast US, we examined a) clinicians' management plans; b) biopsy rate; c) cancer detection rate; c) rate of benign diagnoses; d) cancers diagnosed among patients who were sent home after initial evaluation. Results: Between January 1, 2016 and September 30, 2017, 307 patients with breast concerns had a diagnostic breast US and a documented trainee US assessment. Of these, following their initial US, 158 (51%) were recommended to receive a biopsy, 30 (10%) were recommended to have aspiration/drainage, 49 (16%) were recommended for clinical or US surveillance, 1 (0.3%) was referred to another facility, 65 (21%) were discharged, and 4 (all with no abnormalities on US) had missing recommendations. Of those recommended for biopsy at initial presentation, 151 (96%) had a biopsy at that time. 56 (37%) were diagnosed with breast cancer, 37 (25%) with fibroadenoma, 7 (5%) with lactating adenoma, and 50 (33%) with other benign diagnoses. Among those with breast masses on US (n=255), 149 (58%) received a biopsy and 55 (22%) were diagnosed with cancer. As of November 23, 2017, all patients ultimately diagnosed with cancer had had a biopsy at their initial visit, and no patients who had been discharged or recommended for clinical or radiographic surveillance had been subsequently diagnosed with cancer. Conclusion: Diagnostic breast US by GPs and nurses has been a useful tool in the evaluation of breast lesions, including palpable masses, at a rural cancer facility in Rwanda. Early findings suggest that it has allowed avoidance of biopsy for 42% of patients with breast masses noted on US. Clinical follow-up and evaluation are ongoing to assess longer-term patient outcomes, cancer detection rates among patients who are not initially biopsied, and rates of follow-up among patients recommended to have clinical or radiographic surveillance.

Impact of In-Person and Electronic Training by Breast Radiologists on Rwandan General Practitioners' and Nurses' Skills in Diagnostic Breast Ultrasound

Background: Ultrasound (US) is a key tool in evaluation of palpable breast masses and can help refine the likelihood of malignancy and the need for further diagnostic studies. US technology is available in many low-resource settings, but there are few specialized radiologists. We launched a diagnostic breast ultrasound training program for general practitioner doctors (GPs) and nurses at a rural Rwandan district hospital that serves as a cancer referral facility. Aim: Assess GPs' and nurses' skill in diagnostic breast ultrasound over 23 months of intensive in-person and online supervision and mentorship. Methods: 4 rotating breast radiologists from Brigham and Women's Hospital trained 5 nurses and 4 doctors in Rwanda over 9 weeks of in-person training and 21 months of weekly remote case consultations and mentorship using electronic review of images with emailed feedback. During in-person trainings, trainees and radiologists evaluated patients separately, while radiologists' electronic assessments were based on emailed images and assessments from trainees. Among breast lesions with documented radiologist and trainee assessments, we compared written trainee and radiologist assessments to calculate the sensitivity of trainee assessments, with radiologist assessments as the gold standard. We used paired t-tests to examine whether the sensitivity varied between the first 14 months (stage I) and the last 9 months (stage 2), after the final in-person training. Results: Of 323 breast and axillary lesions assessed by trainees and radiologists, 279 were breast lesions. Of these, 114 (41%) were evaluated by radiologists in-person, and 165 (59%) through electronic evaluation. 237 (85%) were determined to be breast masses by the radiologists, with 164 of these solid masses, 25 complex solid/cystic lesions, 15 definite or probable simple cysts, 31 normal intramammary lymph nodes, and 2 other masses. Sensitivity of trainees' assessments for identifying a solid mass was 90.2% (95% CI 85.9-94.9) overall. Among trainees who scanned ≥ 10 lesions each, mean sensitivity was 90.6% in stage I, and 94.0% in stage 2 ( P = 0.3). In cases where both radiologists and trainees perceived solid masses (n=148), trainees' assessments had a sensitivity of 81.4% (95% CI 72.3-90.5) overall for detecting masses suspicious for malignancy, or probably benign but needing further evaluation (versus benign with no further evaluation needed). Among trainees who scanned ≥ 10 lesions each, sensitivity was 79.1% during stage I and 96.2% during the stage 2 ( P = 0.03). Conclusion: Nurses and GPs in a rural sub-Saharan African facility built strong skills in diagnostic ultrasound over 23 months of combined in-person training and distance learning via electronic case reviews. The sensitivity of their assessments for identifying masses concerning for malignancy showed significant improvement after sustained mentorship. Assessment of impact on patient care and outcomes is ongoing.

Meta-Analysis Comparing Primary Percutaneous Coronary Intervention Versus Pharmacoinvasive Therapy in Transfer Patients with ST-Elevation Myocardial Infarction

ST-elevation myocardial infarction patients presenting at non-percutaneous coronary intervention (PCI)-capable hospitals often need to be transferred for primary percutaneous coronary intervention (PPCI). This increases time to revascularization, leading to increased risk of in-hospital mortality. With recent focus on total ischemic time rather than door-to-balloon time as the principal determinant of outcomes in ST-elevation myocardial infarction patients, pharmacoinvasive therapy (PIT) has gained attention as a possible improvement over PPCI in patients requiring transfer. Our objective was to observe how PIT stands against PPCI in terms of safety and efficacy. Electronic databases were searched for randomized controlled trials and observational studies comparing PPCI to PIT. PIT was defined as administration of thrombolytic drugs followed by immediate PCI only in case of failed thrombolysis. Results from studies were pooled using a random-effects model. We identified 17 relevant studies (6 randomized controlled trials, 11 observational studies) including 13,037 patients. Overall, there was no significant difference in short-term mortality (odds ratio [OR] = 1.20 [0.97 to 1.49]; I² = 14.2%; p = 0.099); however, PIT significantly decreased short-term mortality (OR = 1.46 [1.08 to 1.96]; I² = 0%; p = 0.01) in those studies with a symptom-onset-to-device time ≥200 minutes. There was a significantly lower risk reinfarction (OR = 0.69 [0.49 to 0.97]; I² = 0%; p = 0.033) in the PPCI group, while the risk of cardiogenic shock was significantly higher (OR = 1.48 [1.13 to 1.94]; I² = 0%; p = 0.005). In conclusion, PIT versus PPCI decisions should preferably be customized in patients presenting to non-PCI capable hospitals. Factors that need to be considered include symptom-onset to first medical contact time, expected time of transfer to a PCI-capable hospital, and patients risk factors.