Estrogen receptor-α prevents right ventricular diastolic dysfunction and fibrosis in female rats.

Although women are more susceptible to pulmonary arterial hypertension (PAH) than men, their right ventricular (RV) function is better preserved. Estrogen receptor-α (ERα) has been identified as a likely mediator for estrogen protection in the RV. However, the role of ERα in preserving RV function and remodeling during pressure overload remains poorly understood. We hypothesized that loss of functional ERα removes female protection from adverse remodeling and is permissive for the development of a maladapted RV phenotype. Male and female rats with a loss-of-function mutation in ERα (ERαMut) and wild-type (WT) littermates underwent RV pressure overload by pulmonary artery banding (PAB). At 10 wk post-PAB, WT and ERαMut demonstrated RV hypertrophy. Analysis of RV pressure waveforms demonstrated RV-pulmonary vascular uncoupling and diastolic dysfunction in female, but not male, ERαMut PAB rats. Similarly, female, but not male, ERαMut exhibited increased RV fibrosis, comprised primarily of thick collagen fibers. There was an increased protein expression ratio of TIMP metallopeptidase inhibitor 1 (Timp1) to matrix metalloproteinase 9 (Mmp9) in female ERαMut compared with WT PAB rats, suggesting less collagen degradation. RNA-sequencing in female WT and ERαMut RV revealed kallikrein-related peptidase 10 (Klk10) and Jun Proto-Oncogene (Jun) as possible mediators of female RV protection during PAB. In summary, ERα in females is protective against RV-pulmonary vascular uncoupling, diastolic dysfunction, and fibrosis in response to pressure overload. ERα appears to be dispensable for RV adaptation in males. ERα may be a mediator of superior RV adaptation in female patients with PAH.NEW & NOTEWORTHY Using a novel loss-of-function mutation in estrogen receptor-α (ERα), we demonstrate that female, but not male, ERα mutant rats display right ventricular (RV)-vascular uncoupling, diastolic dysfunction, and fibrosis following pressure overload, indicating a sex-dependent role of ERα in protecting against adverse RV remodeling. TIMP metallopeptidase inhibitor 1 (Timp1), matrix metalloproteinase 9 (Mmp9), kallikrein-related peptidase 10 (Klk10), and Jun Proto-Oncogene (Jun) were identified as potential mediators in ERα-regulated pathways in RV pressure overload.

Effect of Transfer Status on Outcomes of Emergency General Surgery Patients.

INTRODUCTION: Transferred emergency general surgery (EGS) patients are a vulnerable, high acuity population. The outcomes of and health care utilization among transferred (TRAN) as compared to directly admitted (DA) patients have been studied primarily using single institution or hospital system data which limits generalizability. We evaluated these outcomes among EGS patients using a national database. METHODS: We identified encounters of patients aged ≥18 years with a diagnosis of EGS as defined by the American Association for the Surgery of Trauma in the 2008-2011 Nationwide Inpatient Sample (NIS). Multivariable regression analyses determined if transfer status independently predicted in-hospital mortality (logistic regression) and morbidity (presence of any complication among those who survived to discharge; logistic regression), cost (log-linear regression), and duration of stay (among those who survived to discharge; log-linear regression) accounting for the NIS sampling design. RESULTS: We identified 274,145 TRAN (57,885 unweighted) and 10,456,100 DA (2,187,132 unweighted) encounters. On univariate analysis, TRAN patients were more likely to have greater comorbidity scores, have Medicare insurance, and reside in an area with a lesser median household income compared to DA patients (p<0.0001). Mortality was greater in the TRAN vs DA groups (4.4% vs 1.6%; p<0.0001). Morbidity (presence of any complication) was also greater among TRAN patients (38.8% vs 26.1%; p<0.0001). Morbidity among TRAN patients was primarily due to urinary- (13.7%), gastrointestinal- (12.9%), and pulmonary-related (13.3%) complications. Median duration of hospital stay was 4.3 days for TRAN vs 3.0 days for DA (p<0.0001) patients. Median cost was greater for TRAN patients ($8,935 vs $7,167; p<0.0001). Regression analyses determined that after adjustment, TRAN patients had statistically significantly greater mortality, morbidity, and cost as well as longer durations of stay. CONCLUSIONS: EGS patients who are transferred experience increased in-hospital morbidity and mortality as well as increased durations of stay and cost. As the population and age of patients diagnosed with EGS conditions increase while the EGS workforce decreases, the need for inter-hospital transfers will increase. Identifying risk factors associated with worse outcomes among transferred patients can inform the design of initiatives in performance improvement and direct the finite resources available to this vulnerable patient population.

Patterns of opioid use in dialysis access procedures.

BACKGROUND: Overprescription of opioids after surgical procedures is recognized as an important contributor to opioid misuse. Dialysis access procedures are commonly performed outpatient operations with few data or guidelines to inform prescription pain management practices. We sought to characterize opioid pain medication use after dialysis access surgery to promote a conservative approach to postoperative opioid prescriptions. METHODS: We performed a retrospective review of patients who underwent surgical dialysis access procedures from August 2018 through January 2019. Patient-reported opioid use information was captured in a brief questionnaire administered during routine follow-up appointments or phone calls and recorded in the electronic medical record. The procedure, type of intraoperative anesthesia or analgesia, postoperative prescription provided, and patient factors (including age, sex, dialysis type, history of chronic pain, and preoperative opioid or benzodiazepine use) were recorded. All procedures were classified by type (arteriovenous fistula or graft with a short incision [AVF-S], arteriovenous fistula or graft with a long incision [AVF-L], or peritoneal dialysis [PD] catheter), and descriptive statistics were performed using R (R Foundation for Statistical Computing, Vienna, Austria). RESULTS: Eighty-six patients underwent dialysis access procedures in the study time frame, of whom 63 were administered the pain questionnaire and 58 quantified opioid use; 85% of patients received a prescription, but 31% took no opioids and 71% used opioids for ≤2 days. Interquartile ranges (25th-75th percentile) of prescription and consumption quantities for patients who underwent AVF-L procedures were 10 to 28 pills and 2.5 to 20 pills; for patients who underwent AVF-S, quantities were 4.0 to 8.4 pills and 0 to 4.3 pills; and PD quantities were 10 pills and 3.3 to 9 pills. Thirty-one patients (53%) reported receiving more pain medication than they used, which resulted in a median of 8 excess pills per patient with an unused pill interquartile range of 0 to 22 pills for AVF-L procedures, 0 to 4.2 pills for AVF-S procedures, and 1.3 to 6.7 pills for PD procedures. Patients who were prescribed oxycodone or had a repeated operation had significantly increased opioid use. CONCLUSIONS: This investigation of opioid use after surgical dialysis access procedures suggests that most patients use relatively few opioid pills after surgery, which translates into overprescription and leftover medication for >50% of patients. A conservative approach to postoperative prescription guidelines using lower prescription quantities would encourage opioid-related risk reduction while providing adequate postoperative analgesia. Recommended quantities for postoperative prescriptions were generated using the 80th percentile consumed and were 0 to 6 pills for brachiobasilic or brachiocephalic fistulas, 0 to 5 pills for basilic vein transposition, 0 to 5 pills for radiocephalic AVF, 0 to 15 pills for upper arm grafts, and 0 to 10 pills for PD catheter placement.

Characteristics and Timing of Interhospital Transfers of Emergency General Surgery Patients.

BACKGROUND: Transferred emergency general surgery (EGS) patients have increased morbidity, mortality, and costs, yet little is known about the characteristics of such transfers. Increasing specialization and a decreasing general surgery workforce have led to concerns about access to care, which may lead to increased transfers. We sought to evaluate the reasons for and timing of transfers for EGS diagnoses. METHODS: We performed a retrospective medical record review of patients transferred to a tertiary academic medical center between January 4, 2014 and March 31, 2016 who had an EGS diagnosis (bowel obstruction, appendicitis, cholecystitis/cholangitis/choledocholithiasis, diverticulitis, mesenteric ischemia, perforated viscus, or postoperative surgical complication). RESULTS: Three hundred thirty-four patients were transferred from 70 hospitals. Transfer reasons varied with the majority due to the need for specialized services (44.3%) or a surgeon (26.6%). Imaging was performed in 95.8% and 35.3% had surgeon contact before transfer. The percentage of patients who underwent procedures at referring facilities was 7.5% (n = 25), while 60.6% (n = 83) underwent procedures following transfer. Mean time between transfer request and arrival at the accepting hospital was lower for patients who subsequently underwent a procedure at the accepting hospital compared to those who did not for patients originating in emergency departments (2.6 versus 3.4 h, P < 0.05) and inpatient units (6.9 versus 14.3 h, P < 0.05). CONCLUSIONS: Interhospital transfers for EGS conditions are frequently motivated by a need for a higher level of care or specialized services as well as a need for a general surgeon. Understanding reasons for transfers can inform decisions regarding the allocation and provision of care for this vulnerable population.

Natural history of the proximal aorta in patients with descending thoracic aortic disease.

OBJECTIVE: This study investigated the growth and behavior of the ascending aorta in patients with descending thoracic aortic disease. METHODS: We examined 200 patients with descending thoracic aortic disease including acute type B dissection (n = 95), chronic type B dissection (n = 38), intramural hematoma (n = 23), and thoracoabdominal aortic aneurysms (n = 44). Images from computed tomography and magnetic resonance imaging were evaluated after three-dimensional reconstruction to examine the growth rate in those with >1 year of imaging follow-up (n = 108). Survival data were derived from all 200 patients in this study. RESULTS: Average proximal aortic dimensions at the index image were relatively small, measuring 3.65 ± 0.51 cm in the root, 3.67 ± 0.48 cm in the ascending aorta, and 3.50 ± 0.44 cm in the proximal arch. Average growth rate was low for the aortic root, ascending aorta, and proximal arch at 0.36 ± 0.64 mm/y, 0.26 ± 0.44 mm/y, and 0.25 ± 0.44 mm/y, respectively. There was no difference in baseline proximal aortic dimensions and growth rate between the four subgroups. An index aortic diameter ≥4.1 cm grew faster than those <4.1 cm at the ascending aorta (P = .028) and proximal arch (P = .019). There was no difference in aortic growth rates at the aortic root (P = .887). After the index scan, five patients underwent six ascending aortic replacement procedures, leading to a 3% ascending aortic intervention rate. Overall median life expectancy was 86.15 years. CONCLUSIONS: Native ascending aortic growth in patients with descending thoracic aortic disease is slow. We suggest regular follow-up for index ascending aorta ≥4.1 cm because of its larger initial size and more rapid growth.

Regulation of cellular oxidative stress and apoptosis by G protein-coupled receptor kinase-2; The role of NADPH oxidase 4.

Cardiac myocyte oxidative stress and apoptosis are considered important mechanisms for the development of heart failure (HF). Chronic HF is characterized by increased circulating catecholamines to augment cardiac output. Long-term stimulation of myocardial ß-adrenergic receptors (ß-ARs) is deleterious in cardiac myocytes, however, the potential mechanisms underlying increased cell death are unclear. We hypothesize that GRK2, a critical regulator of myocardial ß-AR signaling, plays an important role in mediating cellular oxidative stress and apoptotic cell death in response to ß-agonist stimulation. Stimulation of H9c2 cells with a non-selective ß-agonist, isoproterenol (Iso) caused increased oxidative stress and apoptosis. There was also increased Nox4 expression, but no change in Nox2, the primary NADPH isoforms and major sources of ROS generation in cardiac myocytes. Adenoviral-mediated overexpression of GRK2 led to similar increases in ROS production and apoptosis as seen with Iso stimulation. These increases in oxidative stress were abolished by pre-treatment with the non-specific Nox inhibitor, apocynin, or siRNA knockdown of Nox4. Adenoviral-mediated expression of a GRK2 inhibitor prevented ROS production and apoptosis in response to Iso stimulation. ß-Arrestins are signaling proteins that function downstream of GRK2 in ß-AR uncoupling. Adenoviral-mediated overexpression of ß-arrestins increased ROS production and Nox4 expression. Chronic ß-agonist stimulation in mice increased Nox4 expression and apoptosis compared to PBS or AngII treatment. These data demonstrate that GRK2 may play an important role in regulating oxidative stress and apoptosis in cardiac myocytes and provides an additional novel mechanism for the beneficial effects of cardiac-targeted GRK2 inhibition to prevent the development of HF.

Regulation of mitochondrial oxidative stress by ß-arrestins in cultured human cardiac fibroblasts.

Oxidative stress in cardiac fibroblasts (CFs) promotes transformation to myofibroblasts and collagen synthesis leading to myocardial fibrosis, a precursor to heart failure (HF). NADPH oxidase 4 (Nox4) is a major source of cardiac reactive oxygen species (ROS); however, mechanisms of Nox4 regulation are unclear. ß-arrestins are scaffold proteins that signal in G-protein-dependent and -independent pathways; for example, in ERK activation. We hypothesize that ß-arrestins regulate oxidative stress in a Nox4-dependent manner and increase fibrosis in HF. CFs were isolated from normal and failing adult human left ventricles. Mitochondrial ROS/superoxide production was quantitated using MitoSox. ß-arrestin and Nox4 expressions were manipulated using adenoviral overexpression or short interfering RNA (siRNA)-mediated knockdown. Mitochondrial oxidative stress and Nox4 expression in CFs were significantly increased in HF. Nox4 knockdown resulted in inhibition of mitochondrial superoxide production and decreased basal and TGF-ß-stimulated collagen and α-SMA expression. CF ß-arrestin expression was upregulated fourfold in HF. ß-arrestin knockdown in failing CFs decreased ROS and Nox4 expression by 50%. ß-arrestin overexpression in normal CFs increased mitochondrial superoxide production twofold. These effects were prevented by inhibition of either Nox or ERK. Upregulation of Nox4 seemed to be a primary mechanism for increased ROS production in failing CFs, which stimulates collagen deposition. ß-arrestin expression was upregulated in HF and plays an important and newly identified role in regulating mitochondrial superoxide production via Nox4. The mechanism for this effect seems to be ERK-mediated. Targeted inhibition of ß-arrestins in CFs might decrease oxidative stress as well as pathological cardiac fibrosis.

High-molecular-weight polyethylene glycol inhibits myocardial ischemia-reperfusion injury in vivo.

OBJECTIVES: Cardiac ischemia-reperfusion (I-R) injury remains a significant problem as there are no therapies available to minimize the cell death that can lead to impaired function and heart failure. We have shown that high-molecular-weight polyethylene glycol (PEG) (15-20 kD) can protect cardiac myocytes in vitro from hypoxia-reoxygenation injury. In this study, we investigated the potential protective effects of PEG in vivo. METHODS: Adult rats underwent left anterior descending artery occlusion for 60 minutes followed by 48 hours or 4 weeks of reperfusion. One milliliter of 10% PEG solution or phosphate-buffered saline (PBS) control (n = 10 per group) was administered intravenously (IV) immediately before reperfusion. RESULTS: Fluorescein-labeled PEG was robustly visualized in the myocardium 1 hour after IV delivery. The PEG group had significant recovery of left ventricular ejection fraction at 4 weeks versus a 25% decline in the PBS group (P < .01). There was 50% less LV fibrosis in the PEG group versus PBS with smaller peri-infarct and remote territory fibrosis (P < .01). Cell survival signaling was upregulated in the PEG group with increased Akt (3-fold, P < .01) and ERK (4-fold, P < .05) phosphorylation compared to PBS controls at 48 hours. PEG also inhibited apoptosis as measured by TUNEL-positive nuclei (56% decrease, P < .02) and caspase 3 activity (55% decrease, P < .05). CONCLUSIONS: High-molecular-weight PEG appears to have a significant protective effect from I-R injury in the heart when administered IV immediately before reperfusion. This may have important clinical translation in the setting of acute coronary revascularization and myocardial protection in cardiac surgery.

Durability of De Vega tricuspid valve annuloplasty for severe tricuspid regurgitation during left ventricular assist device implantation.

BACKGROUND: Correction of significant tricuspid regurgitation (TR) at the time of continuous-flow (CF) left ventricular assist device (LVAD) implantation has been shown to be beneficial in several recently published studies. The most common technique is ring annuloplasty followed by valve replacement. Our center has primarily used the De Vega annuloplasty, and the durability of this repair is the focus of this study. METHODS: This was a retrospective review of 35 consecutive patients who underwent CF LVAD implantation and De Vega tricuspid valve annuloplasty (TVA) for severe TR and were alive at 1 year. Echocardiograms were obtained preoperatively, intraoperatively, at discharge, and at 1 year after operation. RESULTS: The TR in 32 of 35 patients (91.4%, group A) improved from severe preoperatively to insignificant at the time of discharge after De Vega TVA, and 3 patients (8.6%, group B) had moderate residual TR. At 1-year follow-up, 29 of 32 (90.6%) patients in group A had insignificant TR, 2 (6.3%) had moderate TR, and 1 (3.1%) had severe TR. In group B, 2 of 3 patients had no progression of their moderate TR at 1 year and 1 had severe TR. Overall, 2 of 35 (5.7%) patients had severe TR at 1 year after De Vega TVA and LVAD implantation. CONCLUSIONS: We conclude from this consecutive cohort of patients undergoing CF LVAD implantation and De Vega TVA that this technique is very durable at 1 year and has the advantages of a shorter operative time relative to ring annuloplasty and decreased cost because a prosthetic implant is not used.

G protein-coupled receptor kinase-2 is a novel regulator of collagen synthesis in adult human cardiac fibroblasts.

Cardiac fibroblasts (CF) make up 60-70% of the total cell number in the heart and play a critical role in regulating normal myocardial function and in adverse remodeling following myocardial infarction and the transition to heart failure. Recent studies have shown that increased intracellular cAMP can inhibit CF transformation and collagen synthesis in adult rat CF; however, mechanisms by which cAMP production is regulated in CF have not been elucidated. We investigated the potential role of G protein-coupled receptor kinase-2 (GRK2) in modulating collagen synthesis by adult human CF isolated from normal and failing left ventricles. Baseline collagen synthesis was elevated in failing CF and was not inhibited by ß-agonist stimulation in contrast to normal controls. ß-adrenergic receptor (ß-AR) signaling was markedly uncoupled in the failing CF, and expression and activity of GRK2 were increased 3-fold. Overexpression of GRK2 in normal CF recapitulated a heart failure phenotype with minimal inhibition of collagen synthesis following ß-agonist stimulation. In contrast, knockdown of GRK2 expression in normal CF enhanced cAMP production and led to greater ß-agonist-mediated inhibition of basal and TGFß-stimulated collagen synthesis versus control. Inhibition of GRK2 activity in failing CF by expression of the GRK2 inhibitor, GRK2ct, or siRNA-mediated knockdown restored ß-agonist-stimulated inhibition of collagen synthesis and decreased collagen synthesis in response to TGFß stimulation. GRK2 appears to play a significant role in regulating collagen synthesis in adult human CF, and increased activity of this kinase may be an important mechanism of maladaptive ventricular remodeling as mediated by cardiac fibroblasts.