Retrieval of renal function after renal artery stenting improves event-free survival in a subgroup analysis of the Cardiovascular Outcomes in Renal Atherosclerotic Lesions trial.

OBJECTIVE: The Cardiovascular Outcomes in Renal Atherosclerotic Lesions (CORAL) trial, a multicenter randomized controlled trial with 947 patients, concluded that there was no benefit of renal artery stenting (RAS) over medical therapy. However, patients with chronic kidney disease (CKD) were not analyzed separately in the CORAL trial. CKD is a risk factor for cardiovascular and renal morbidity. We hypothesized that improved renal function after RAS would be associated with increased long-term survival and a lower risk of cardiovascular and renal events in patients with CKD. METHODS: This post hoc analysis of the CORAL trial included 842 patients with CKD stages 2 to 4 at baseline who were randomized to optimal medical therapy alone (OMT; n = 432) or RAS plus OMT (RAS + OMT; n = 410). Patients were categorized as responders or nonresponders based on the change in the estimated glomerular filtration rate (eGFR) from baseline to last follow-up (median, 3.6 years; interquartile range, 2.6-4.6 years). Responders were defined by a 20% or greater increase in eGFR from baseline; all others were designated as nonresponders. Event-free survival was defined as freedom from death and multiple cardiovascular and renal complications. Event-free survival was analyzed using the Kaplan-Meier method and log-rank test. Multivariable Cox proportional hazards regression analysis was used to identify independent predictors of event-free survival. RESULTS: The RAS + OMT group had a higher proportion of patients with improved renal function (≥20% increase in eGFR over baseline), compared with the OMT group (25.6% vs 17.1%; P = .003). However, event-free survival was no different for the two cohorts (P = .18 by the log-rank test). Multivariable Cox proportional hazards regression analysis identified four variables that independently correlated with event-free survival for the stented cohort. Higher preoperative eGFR (hazard ratio, 0.98; 95% confidence interval [CI], 0.96-0.99; P = .002) and being a responder to stenting (hazard ratio, 0.49; 95% CI, 0.26-0.95; P = .033) increased event-free survival, whereas a history of congestive heart failure (hazard ratio, 2.52; 95% CI, 1.46-4.35; P < .001) and a higher preoperative systolic BP (hazard ratio, 1.02; 95% CI, 1.01-1.03; P = .002) decreased event-free survival. Within the stented group, 105 of 410 patients (25.6%) were responders. Event-free survival was superior for responders, compared with nonresponders (P = .009 by log-rank test). The only independent preoperative negative predictor of improved renal function after stenting was diabetes (odds ratio, 0.37; 95% CI, 0.16-0.84; P = .017), which decreased the probability of improved renal function after RAS + OMT. A subset of patients (23.4%) after RAS had worsened renal function, but OMT alone produced an equivalent incidence of worsened renal function. An increased urine albumin/creatinine ratio was an independent predictor of worsened renal function after RAS. CONCLUSIONS: CORAL participants who demonstrated improved kidney function after RAS + OMT demonstrated improved event-free survival. This finding reinforces the need for predictors of outcome to guide patient selection for RAS.

Hemopexin accumulates in kidneys and worsens acute kidney injury by causing hemoglobin deposition and exacerbation of iron toxicity in proximal tubules.

Hemopexin, a heme scavenging protein, accumulates in the kidneys during acute kidney injury (AKI). However, the function of this accumulated hemopexin in the kidney is unclear. In both the cisplatin-induced and the unilateral kidney ischemia-reperfusion injury models of AKI, we found accumulation of hemoglobin and hemopexin in the kidneys localized to the proximal tubules. Next, hemopexin wild-type and knockout mice were compared in both AKI models and hemopexin wild type mice had significantly worse kidney injury. Furthermore, there was increased kidney expression of kidney injury molecule-1 (a biomarker of AKI) and heme oxygenase-1 (an indicator of oxidative stress) in hemopexin wild type compared with knockout mice in both models of AKI. Next, the interaction of hemopexin and hemoglobin in vitro was investigated using cultured proximal tubular cells. Co-incubation of hemopexin with hemoglobin resulted in hemoglobin deposition and exaggerated hemoglobin-induced injury. Deferoxamine, an iron chelator, and ferrostatin-1, a ferroptosis inhibitor, inhibited this deleterious effect of hemoglobin and hemopexin in proximal tubular cells, implicating iron toxicity in the mechanism of hemopexin mediated injury. Furthermore, the protective effect of deferoxamine in cisplatin-induced AKI was apparent in hemopexin wild type, but not in hemopexin knockout mice, further implicating hemopexin as a mediator of iron toxicity in AKI. Thus, our findings demonstrate that hemopexin accumulates in the kidneys and worsens kidney injury in AKI by increasing hemoglobin deposition on proximal tubular cells to exaggerate hemoglobin-induced cell injury.

Atherosclerotic Renovascular Disease: A KDIGO (Kidney Disease: Improving Global Outcomes) Controversies Conference.

The diagnosis and management of atherosclerotic renovascular disease (ARVD) is complex and controversial. Despite evidence from the ASTRAL (2009) and CORAL (2013) randomized controlled trials showing that percutaneous renal artery revascularization did not improve major outcomes compared with best medical therapy alone over 3-5 years, several areas of uncertainty remain. Medical therapy, including statin and antihypertensive medications, has evolved in recent years, and the use of renin-angiotensin-aldosterone system blockers is now considered the primary means to treat hypertension in the setting of ARVD. However, the criteria to identify kidneys with renal artery stenosis that have potentially salvageable function are evolving. There are also data suggesting that certain high-risk populations with specific clinical manifestations may benefit from revascularization. Here, we provide an overview of the epidemiology, diagnosis, and treatment of ARVD based on consensus recommendations from a panel of physician experts who attended the recent KDIGO (Kidney Disease: Improving Global Outcomes) Controversies Conference on central and peripheral arterial diseases in chronic kidney disease. Most focus is provided for contentious issues, and we also outline aspects of investigation and management of ARVD that require further research.

Long-term mortality after massive, submassive, and low-risk pulmonary embolism.

Guidelines for management of normotensive patients with acute pulmonary embolism (PE) emphasize further risk stratification on the basis of right ventricular (RV) size and biomarkers of RV injury or strain; however, the prognostic importance of these factors on long-term mortality is not known. We performed a retrospective cohort study of subjects diagnosed with acute PE from 2010 to 2015 at a tertiary care academic medical center. The severity of initial PE presentation was categorized into three groups: massive, submassive, and low-risk PE. The primary endpoint of all-cause mortality was ascertained using the Centers for Disease Control National Death Index (CDC NDI). A total of 183 subjects were studied and their median follow-up was 4.1 years. The median age was 65 years. The 30-day mortality rate was 7.7% and the overall mortality rate through the end of follow-up was 40.4%. The overall mortality rates for massive, submassive, and low-risk PE were 71.4%, 44.5%, and 28.1%, respectively (p < 0.001). Landmark analysis using a 30-day cutpoint demonstrated that subjects presenting with submassive PE compared with low-risk PE had increased mortality during both the short- and the long-term periods. The most frequent causes of death were malignancy, cardiac disease, respiratory disease, and PE. Independent predictors of all-cause mortality were cancer at baseline, age, white blood cell count, diabetes mellitus, liver disease, female sex, and initial presentation with massive PE. In conclusion, the diagnosis of acute PE was associated with substantial long-term mortality. The severity of initial PE presentation was associated with both short- and long-term mortality.

Renal Artery Stenosis and Congestive Heart Failure: What Do We Really Know?

PURPOSE OF REVIEW: Congestive heart failure (CHF) is a major cause of morbidity, mortality, and health care expenditure. Although the role of renal artery stenosis (RAS) in CHF has been known, there are a number of areas of uncertainty. RECENT FINDINGS: The prevalence of RAS in subjects with CHF varies from 15 to 54% depending on the cohort studied and the diagnostic modality used to identify RAS. In subjects with CHF, the presence of RAS is associated with worse renal function and a higher risk for mortality during long-term follow-up. There are many unanswered questions regarding the role of RAS in subjects with CHF. This review highlights those questions and helps to set the research agenda in this area.

Short- and Long-term Mortality Risk After Acute Pulmonary Embolism.

PURPOSE OF REVIEW: Acute pulmonary embolism is a major cause of morbidity and mortality in the USA and throughout the world. This review will summarize recent developments in short- and long-term mortality risk assessment after an acute pulmonary embolism. RECENT FINDINGS: Recent guidelines have emphasized risk stratification of acute PE patients on the basis of blood pressure, right ventricular size, and biomarker status. Ongoing work is testing various acute treatment strategies for improvement of symptom burden, length of stay, quality of life, and possibly mortality risk reduction. Long-term outcomes among subjects with acute PE are less well studied. Long-term mortality largely correlates with baseline co-morbidity burden, although there may be an association between acute PE severity and long-term outcomes. Acute PE risk stratification and treatment, as well as long-term follow-up of patients with acute PE, are rapidly developing areas and many promising innovations are underway.

Targeted disruption of Cd40 in a genetically hypertensive rat model attenuates renal fibrosis and proteinuria, independent of blood pressure.

High blood pressure is a common cause of chronic kidney disease. Because CD40, a member of the tumor necrosis factor receptor family, has been linked to the progression of kidney disease in ischemic nephropathy, we studied the role of Cd40 in the development of hypertensive renal disease. The Cd40 gene was mutated in the Dahl S genetically hypertensive rat with renal disease by targeted-gene disruption using zinc-finger nuclease technology. These rats were then given low (0.3%) and high (2%) salt diets and compared. The resultant Cd40 mutants had significantly reduced levels of both urinary protein excretion (41.8 ± 3.1 mg/24 h vs. 103.7 ± 4.3 mg/24 h) and plasma creatinine (0.36 ± 0.05 mg/dl vs. 1.15 ± 0.19 mg/dl), with significantly higher creatinine clearance compared with the control S rats (3.04 ± 0.48 ml/min vs. 0.93 ± 0.15 ml/min), indicating renoprotection was conferred by mutation of the Cd40 locus. Furthermore, the Cd40 mutants had a significant attenuation in renal fibrosis, which persisted on the high salt diet. However, there was no difference in systolic blood pressure between the control and Cd40 mutant rats. Thus, these data serve as the first evidence for a direct link between Cd40 and hypertensive nephropathy. Hence, renal fibrosis is one of the underlying mechanisms by which Cd40 plays a crucial role in the development of hypertensive renal disease.

Stenting and medical therapy for atherosclerotic renal-artery stenosis.

BACKGROUND: Atherosclerotic renal-artery stenosis is a common problem in the elderly. Despite two randomized trials that did not show a benefit of renal-artery stenting with respect to kidney function, the usefulness of stenting for the prevention of major adverse renal and cardiovascular events is uncertain. METHODS: We randomly assigned 947 participants who had atherosclerotic renal-artery stenosis and either systolic hypertension while taking two or more antihypertensive drugs or chronic kidney disease to medical therapy plus renal-artery stenting or medical therapy alone. Participants were followed for the occurrence of adverse cardiovascular and renal events (a composite end point of death from cardiovascular or renal causes, myocardial infarction, stroke, hospitalization for congestive heart failure, progressive renal insufficiency, or the need for renal-replacement therapy). RESULTS: Over a median follow-up period of 43 months (interquartile range, 31 to 55), the rate of the primary composite end point did not differ significantly between participants who underwent stenting in addition to receiving medical therapy and those who received medical therapy alone (35.1% and 35.8%, respectively; hazard ratio with stenting, 0.94; 95% confidence interval [CI], 0.76 to 1.17; P=0.58). There were also no significant differences between the treatment groups in the rates of the individual components of the primary end point or in all-cause mortality. During follow-up, there was a consistent modest difference in systolic blood pressure favoring the stent group (-2.3 mm Hg; 95% CI, -4.4 to -0.2; P=0.03). CONCLUSIONS: Renal-artery stenting did not confer a significant benefit with respect to the prevention of clinical events when added to comprehensive, multifactorial medical therapy in people with atherosclerotic renal-artery stenosis and hypertension or chronic kidney disease. (Funded by the National Heart, Lung and Blood Institute and others; ClinicalTrials.gov number, NCT00081731.).

Clinical outcomes associated with per-operative discontinuation of aspirin in patients with coronary artery disease: A systematic review and meta-analysis.

BACKGROUND: Postoperative state is characterized by increased thrombotic risk by virtue of platelet activation. Whether aspirin ameliorates this risk in patients with established coronary artery disease undergoing cardiac or noncardiac surgery is unknown. We conducted a systematic review and meta-analysis to compare the risk of major adverse cardiac events (MACE) and the risk of bleeding in patients with early (3-5 or more days before surgery) vs. late discontinuation(<3-5 days)/no discontinuation of aspirin. METHODS: Multiple databases were searched from inception of these databases until March 2015 to identify studies that reported discontinuation of aspirin in patients undergoing surgery. The outcomes measured were all cause mortality, nonfatal myocardial infarction and other relevant thrombotic events (MACE) which also may include, fatal and nonfatal MI, stent thrombosis and restenosis, stroke, perioperative cardiovascular complications (heart failure, MI, VTE, acute stroke) and perioperative bleeding during the perioperative period to up to 30 days after surgery. RESULTS: A total of 1,018 titles were screened, after which six observational studies met the inclusion criteria. Our analysis suggests that there is no difference in MACE with planned discontinuation of aspirin (OR = 1.17, 95% CI = 0.76-1.81; P = 0.05; I2 = 55%). Early discontinuation of aspirin showed a decreased risk of peri-operative bleeding (OR 0.82, 95% CI = 0.67-0.99; P = 0.04; I2 = 42%). CONCLUSION: Our analysis suggests that planned short-term discontinuation in the appropriate clinical setting appears to be safe in the correct clinical setting with no increased risk of thrombotic events and with a decreased risk of bleeding. © 2016 Wiley Periodicals, Inc.

Renal Artery Stenosis: New Findings from the CORAL Trial.

PURPOSE OF REVIEW: The goal of this review is to summarize recent advances in the field and highlight important new insights from the Cardiovascular Outcomes in Renal Atherosclerotic Lesions (CORAL) trial regarding the optimal management of patients with renal artery stenosis (RAS). RECENT FINDINGS: The CORAL trial demonstrated that subjects with RAS had similar outcomes whether randomized to optimal medical therapy alone or optimal medical therapy plus renal artery stenting. Subgroup analyses have failed to demonstrate that baseline blood pressure or lesion gradients can predict which subjects may have improved response after stent intervention. Importantly, urine albumin to creatinine ratio appears to different subjects that may benefit from stent intervention versus subjects that are unlikely to achieve any benefit. In addition, there was a trend toward increase benefit in subjects with greater percent stenosis. Atherosclerotic RAS is a frequent finding and is often seen in patients with resistant hypertension, congestive heart failure, chronic kidney disease, and rarely those who need renal replacement therapy. Risk factors for RAS overlap with those of generalized atherosclerosis including hyperlipidemia, smoking, hypertension, and diabetes. Patients with CAD or PVD frequently have co-existing RAS. The management of RAS has been controversial for many years. The CORAL trial provides important insights into the optimal management of subjects with RAS.

Na/K-ATPase signaling regulates collagen synthesis through microRNA-29b-3p in cardiac fibroblasts.

Chronic kidney disease (CKD) is accompanied by cardiac fibrosis, hypertrophy, and dysfunction, which are commonly referred to as uremic cardiomyopathy. Our previous studies found that Na/K-ATPase ligands or 5/6th partial nephrectomy (PNx) induces cardiac fibrosis in rats and mice. The current study used in vitro and in vivo models to explore novel roles for microRNA in this mechanism of cardiac fibrosis formation. To accomplish this, we performed microRNA profiling with RT-qPCR based arrays on cardiac tissue from rats subjected to marinobufagenin (MBG) infusion or PNx. The analysis showed that a series of fibrosis-related microRNAs were dysregulated. Among the dysregulated microRNAs, microRNA (miR)-29b-3p, which directly targets mRNA of collagen, was consistently reduced in both PNx and MBG-infused animals. In vitro experiments demonstrated that treatment of primary cultures of adult rat cardiac fibroblasts with Na/K-ATPase ligands induced significant increases in the fibrosis marker, collagen protein, and mRNA expression compared with controls, whereas miR-29b-3p expression decreased >50%. Transfection of miR-29b-3p mimics into cardiac fibroblasts inhibited cardiotonic steroids-induced collagen synthesis. Moreover, a specific Na/K-ATPase signaling antagonist, pNaKtide, prevented ouabain-induced increases in collagen synthesis and decreases in miR-29b-3p expression in these cells. In conclusion, these data are the first to indicate that signaling through Na/K-ATPase regulates miRNAs and specifically, miR-29b-3p expression both in vivo and in vitro. Additionally, these data indicate that miR-29b-3p expression plays an important role in the formation of cardiac fibrosis in CKD.

Cigarette smoking causes epigenetic changes associated with cardiorenal fibrosis.

Clinical studies indicate that smoking combustible cigarettes promotes progression of renal and cardiac injury, leading to functional decline in the setting of chronic kidney disease (CKD). However, basic studies using in vivo small animal models that mimic clinical pathology of CKD are lacking. To address this issue, we evaluated renal and cardiac injury progression and functional changes induced by 4 wk of daily combustible cigarette smoke exposure in the 5/6th partial nephrectomy (PNx) CKD model. Molecular evaluations revealed that cigarette smoke significantly (P < 0.05) decreased renal and cardiac expression of the antifibrotic microRNA miR-29b-3 and increased expression of molecular fibrosis markers. In terms of cardiac and renal organ structure and function, exposure to cigarette smoke led to significantly increased systolic blood pressure, cardiac hypertrophy, cardiac and renal fibrosis, and decreased renal function. These data indicate that decreased expression of miR-29b-3p is a novel mechanism wherein cigarette smoke promotes accelerated cardiac and renal tissue injury in CKD. (155 words).

An alternative empirical likelihood method in missing response problems and causal inference.

Missing responses are common problems in medical, social, and economic studies. When responses are missing at random, a complete case data analysis may result in biases. A popular debias method is inverse probability weighting proposed by Horvitz and Thompson. To improve efficiency, Robins et al. proposed an augmented inverse probability weighting method. The augmented inverse probability weighting estimator has a double-robustness property and achieves the semiparametric efficiency lower bound when the regression model and propensity score model are both correctly specified. In this paper, we introduce an empirical likelihood-based estimator as an alternative to Qin and Zhang (2007). Our proposed estimator is also doubly robust and locally efficient. Simulation results show that the proposed estimator has better performance when the propensity score is correctly modeled. Moreover, the proposed method can be applied in the estimation of average treatment effect in observational causal inferences. Finally, we apply our method to an observational study of smoking, using data from the Cardiovascular Outcomes in Renal Atherosclerotic Lesions clinical trial. Copyright © 2016 John Wiley & Sons, Ltd.

Reduction of Na/K-ATPase affects cardiac remodeling and increases c-kit cell abundance in partial nephrectomized mice.

The current study examined the role of Na/K-ATPase α1-subunit in animals subjected to 5/6th partial nephrectomy (PNx) using Na/K-ATPase α1-heterozygous (α1(+/-)) mice and their wild-type (WT) littermates. After PNx, both WT and α1(+/-) animals displayed diastolic dimension increases, increased blood pressure, and increased cardiac hypertrophy. However, in the α1(+/-) animals we detected significant increases in cardiac cell death in PNx animals. Given that reduction of α1 elicited increased cardiac cell death with PNx, while at the same time these animals developed cardiac hypertrophy, an examination of cardiac cell number, and proliferative capabilities of those cells was carried out. Cardiac tissues were probed for the progenitor cell marker c-kit and the proliferation marker ki-67. The results revealed that α1(+/-) mice had significantly higher numbers of c-kit-positive and ki-67-positive cells, especially in the PNx group. We also found that α1(+/-) mice express higher levels of stem cell factor, a c-kit ligand, in their heart tissue and had higher circulating levels of stem cell factor than WT animals. In addition, PNx induced significant enlargement of cardiac myocytes in WT mice but has much less effect in α1(+/-) mice. However, the total cell number determined by nuclear counting is higher in α1(+/-) mice with PNx compared with WT mice. We conclude that PNx induces hypertrophic growth and high blood pressure regardless of Na/K-ATPase content change. However, total cardiac cell number as well as c-kit-positive cell number is increased in α1(+/-) mice with PNx.

Endovascular versus medical therapy for atherosclerotic renovascular disease.

The diagnosis of renal artery stenosis (RAS) has become increasingly common in part due to greater awareness of ischemic renal disease and increased use of diagnostic techniques. Over 90 % of RAS cases are caused by atherosclerotic renovascular disease (ARVD). Patients with ARVD are at high risk for fatal and nonfatal cardiovascular and renal events. The mortality rate in patients with ARVD is high, especially with other cardiovascular or renal comorbidities. Recent clinical studies have provided substantial evidence concerning medical therapy and endovascular interventional therapeutic approaches for ARVD. Despite previous randomized clinical trials, the optimal therapy for ARVD remained uncertain until the results of the Cardiovascular Outcomes in Renal Atherosclerotic Lesions (CORAL) trial were released recently. CORAL demonstrated that optimal medical therapy was equally effective to endovascular therapy in the treatment of ARVD. Clinicians can now practice with more evidence-based medicine to treat ARVD and potentially decrease mortality in patients with ARVD using optimal medical therapy.

Roll-in experience from the Cardiovascular Outcomes with Renal Atherosclerotic Lesions (CORAL) study.

PURPOSE: To describe the experience and results from the roll-in phase of the Cardiovascular Outcomes with Renal Atherosclerotic Lesions (CORAL) study. MATERIALS AND METHODS: The CORAL roll-in database was used to describe the baseline characteristics of the patients in the roll-in cohort, all of whom underwent renal artery stent placement; to evaluate CORAL site performance; to compare estimates of lesion (stenosis) severity made by site interventionalists with the central CORAL angiographic core laboratory readings; and to report outcomes after renal artery stent placement. During the roll-in phase, 239 patients (mean age, 70.2 y ± 9.0; 49% male) underwent renal artery stent procedures. Angiographic core laboratory analysis of renal arteriograms was done, and participants were followed at 1 month and 9 months. RESULTS: Major angiographic complications were identified in 28 (13%) subjects. Kidney function remained unchanged at the short (2-4 weeks) follow-up interval. Improvement in systolic blood pressure with use of distal embolic protection devices (n = 161) did not show any clinical benefit over nonuse of such devices (n = 78) in this small series. At 9 months, there were significantly more endpoints reported by site in subjects with bilateral renal artery stenosis (P = .01) and prior history of stroke (P = .03). CONCLUSIONS: In the roll-in phase of the CORAL study, a significant number of angiographic complications were identified. No effect was seen on estimated glomerular filtration rate after renal artery stent placement, but systolic blood pressure decreased significantly.

Is fibromuscular dysplasia underdiagnosed? A comparison of the prevalence of FMD seen in CORAL trial participants versus a single institution population of renal donor candidates.

Renal artery fibromuscular dysplasia (FMD) may be underdiagnosed. We evaluated the prevalence of FMD in CORAL (Cardiovascular Outcomes in Renal Atherosclerotic Lesions) renal artery stent trial participants, in which FMD was an exclusion criterion for inclusion. We also evaluated the prevalence of FMD in a relatively healthy population of patients undergoing computed tomographic angiographic (CTA) screening for renal donor evaluation. All renal donor CTAs performed at our institution from January 2003 through November 2011 were retrospectively reviewed for the presence of FMD along with patient sex and age. These results were compared to angiographic core lab (ACL) findings for the CORAL trial. The CORAL ACL database contained 997 patients (mean age 69.3 years; 50% female). Fifty-eight (5.8%) CORAL trial patients (mean age 71.8 years; 75.9% female) demonstrated incidental FMD. The renal donor cohort included 220 patients (mean age 40.5 years; 64.5% female). Five (2.3%) demonstrated FMD (mean age 48.6 years; all female). The odds of FMD in the CORAL cohort were 2.65 times that seen in the renal donor cohort (95% CI: 1.12, 7.57). In C: onclusion, the 5.8% prevalence of renal artery FMD in the CORAL trial population, the presence of which was biased against, suggests underdiagnosis.

Reduction of Na/K-ATPase potentiates marinobufagenin-induced cardiac dysfunction and myocyte apoptosis.

Decreases in cardiac Na/K-ATPase have been documented in patients with heart failure. Reduction of Na/K-ATPase α1 also contributes to the deficiency in cardiac contractility in animal models. Our previous studies demonstrate that reduction of cellular Na/K-ATPase causes cell growth inhibition and cell death in renal proximal tubule cells. To test whether reduction of Na/K-ATPase in combination with increased cardiotonic steroids causes cardiac myocyte death and cardiac dysfunction, we examined heart function in Na/K-ATPase α1 heterozygote knock-out mice (α1(+/-)) in comparison to wild type (WT) littermates after infusion of marinobufagenin (MBG). Adult cardiac myocytes were also isolated from both WT and α1(+/-) mice for in vitro experiments. The results demonstrated that MBG infusion increased myocyte apoptosis and induced significant left ventricle dilation in α1(+/-) mice but not in their WT littermates. Mechanistically, it was found that in WT myocytes MBG activated the Src/Akt/mTOR signaling pathway, which further increased phosphorylation of ribosome S6 kinase (S6K) and BAD (Bcl-2-associated death promoter) and protected cells from apoptosis. In α1(+/-) myocytes, the basal level of phospho-BAD is higher compared with WT myocytes, but MBG failed to induce further activation of the mTOR pathway. Reduction of Na/K-ATPase also caused the activation of caspase 9 but not caspase 8 in these cells. Using cultures of neonatal cardiac myocytes, we demonstrated that inhibition of the mTOR pathway by rapamycin also enabled MBG to activate caspase 9 and induce myocyte apoptosis.

Illicit narcotic injection masquerading as acute pulmonary embolism.

A 23-year-old male presented from a nursing home with hypotension, tachycardia, diaphoresis and electrocardiographic evidence of right ventricular strain that was confirmed by echocardiography. His differential diagnosis included sepsis and pulmonary embolism. A high-resolution computed tomography scan demonstrated no pulmonary emboli but did demonstrate multiple bilateral pulmonary nodules. Upon questioning he admitted to injecting a long-acting narcotic that had been manually macerated, dissolved in saline, and injected through an indwelling intravenous line. Lung biopsy findings were consistent with cellulose-induced perivascular granulomatosis. Cellulose granulomatosis can be seen in patients who inject medications designed for oral use and should be considered in patients who present with acute pulmonary hypertension.

Utility of Prehospital Quantitative End Tidal CO2?

INTRODUCTION: End tidal CO2 (ETCO2) has been established as a standard for confirmation of an airway, but its role is expanding. In certain settings ETCO2 closely approximates the partial pressure of arterial CO2 (PaCO2) and has been described as a tool to optimize a patient's ventilatory status. ETCO2 monitors are increasingly being used by EMS personnel to guide ventilation in the prehospital setting. Severely traumatized and burn patients represent a unique population to which this practice has not been validated. HYPOTHESIS: The sole use of ETCO2 to monitor ventilation may lead to avoidable respiratory acidosis. METHODS: A consecutive series of patients with burns or trauma intubated in the prehospital setting over a 24-month period were evaluated. Prehospital arrests were excluded. Absence of ETCO2 transport data and patients without an arterial blood gas (ABG) within 15 minutes of arrival were also excluded. Data collected included demographics, place and time of intubation, service performing intubation, ETCO2 maintained en-route to hospital, and ABG upon arrival. Further data included length of stay, mortality, and injury severity scores. RESULTS: One hundred sixty patients met the inclusion criteria. Prehospital ETCO2 did not correlate with measured PaCO2 (R2 = 0.08). Mean ETCO2 was significantly lower than mean PaCO2 (34 mmHg vs 44 mmHg, P < .005). Patients arriving acidotic were more likely to die. Mean pH on arrival for survivors and decedents was 7.32 and 7.19 respectively (P < .001). Mortality, acidosis, higher base deficits, and more severe injury patterns were all predictors for a worse correlation between ETCO2 and PaCO2 and increased mean difference between the two values. Decedents and patients presenting with a pH <7.2 demonstrated the greatest discrepancy between ETCO2 and PaCO2. The data suggest that patients may be hypoventilated by prehospital providers in order to obtain a prescribed ETCO2. CONCLUSION: ETCO2 is an inadequate tool for predicting PaCO2 or optimizing ventilation in severely injured patients. Adherence to current ETCO2 guidelines in the prehospital setting may contribute to acidosis and increased mortality. Consideration should be given to developing alternate protocols to guide ventilation of the severely injured in the prehospital setting.