Safety and indications for endoscopic retrograde cholangiopancreatography in liver transplant patients: an analysis of the United States' National Inpatient Sample database

Background

Endoscopic retrograde cholangiopancreatography (ERCP) is performed to treat biliary complications after a liver transplantation; however, the previously available literature on the safety of ERCP in liver transplant patients is limited. We aimed to study the safety of ERCP in liver transplant patients.

Methods

We used a National Inpatient Sample database from 2016-2019 to identify patients who underwent ERCP and had a history of a liver transplantation, using the international classification of diseases, 10th revision. Multivariate logistic regression analysis was conducted to determine the odds of post-ERCP complications in liver transplant recipients.

Results

Liver transplant patients who underwent ERCP had a higher rate of post-ERCP pancreatitis and bleeding compared to the general adult population (11.39% vs. 9.19%, 0.83% vs. 0.53%, respectively). However, the adjusted odds of post-ERCP pancreatitis (adjusted odds ratio [aOR] 1.13, 95% confidence interval [CI] 0.86-1.49; P=0.36) and bleeding (aOR 1.41, 95%CI 0.58-3.46; P=0.45) were similar in both the liver transplant and no-transplant groups. There was no difference in the odds of post-ERCP cholangitis (aOR 1.26, 95%CI 0.80-2.01; P=0.32), and sepsis (aOR 0.94, 95%CI 0.66-1.34; P=0.76) between liver transplant and no transplant groups. Biliary stricture was the most common indication for ERCP in the liver transplant group, whereas choledocholithiasis was the main reason for ERCP in the general adult population.

Conclusions

ERCP is a safe procedure for treating biliary complications in liver transplant patients. The odds of post-ERCP complications (pancreatitis, bleeding, sepsis, cholangitis) in liver transplant patients are comparable to those in patients with no transplantation.

The Progression of Celiac Disease, Diagnostic Modalities, and Treatment Options

Celiac disease (CD) is an autoimmune disorder that affects genetically predisposed individuals who are sensitive to gluten and related proteins. It affects children and adults with increasing prevalence in the older age groups. Both adaptive and innate immune responses play role in CD pathogenesis which results in damage of lamina propria and deposition of intraepithelial lymphocytes. There are other proposed mechanisms of CD pathogenesis like gastrointestinal infections, intestinal microbiota, and early introduction of gluten. The diagnosis of CD is based on clinical symptoms and serological testing, though a majority of cases are asymptomatic, and small intestinal biopsies are required to confirm the diagnosis. Celiac disease is generally associated with other autoimmune diseases, and it is advisable to test these patients for diseases like type 1 diabetes mellitus, Addison’s disease, thyroid diseases, inflammatory bowel disease, and autoimmune hepatitis. The patient with a new diagnosis of CD requires close follow-up after starting treatment to see symptom improvement and check dietary compliance. A newly diagnosed patient is advised to follow with a dietitian to better understand the dietary restrictions as about 20% of patients stay symptomatic even after starting treatment due to noncompliance or poor understanding of diet restrictions. The most effective treatment for CD is a gluten-free diet, but work on non-dietary therapy is in process and few medications are in the clinical trial phase.

Does the Route of Cocaine Use Affect the Mortality and Outcomes of Cocaine-Induced Intestinal Ischemia? A Systematic Review

Intestinal ischemia results from diminished perfusion of the colon resulting in tissue hypoxia. Anecdotal reports suggest that cocaine-induced intestinal ischemia has the highest mortality and longer length of stay among the vasoconstrictors. The present study aimed to summarize the available studies in the literature to assess the effect of routes of consumption on the outcomes of cocaine-induced intestinal ischemia. We conducted a systematic search of MEDLINE from inception through October 2019. Studies of cocaine-induced intestinal ischemia were included if data were available on comorbidities, mortality, and hospital length of stay (LOS). The study's primary outcomes were mortality and need for surgery, while secondary outcomes included the hospital length of stay, LACE index, and hospital score. Statistical tests used included linear and binary logistic regression. STATA 2015 was used, and P < 0.05 was statistically significant. Of the 304 studies, 8 case series and 45 case reports (n = 69 patients) met the inclusion criteria. Different routes of cocaine use had similar mortality odds and the need for surgery for intestinal ischemia. Hospital LOS showed significant difference among the subgroups. Readmission scores (LACE and hospital score) were higher for intravenous and smoking than ingestion and intranasal use (P < 0.05). In conclusion, different routes of cocaine use appear to have similar mortality odds for intestinal ischemia, which vary significantly among the different routes of cocaine consumption for the length of stay and readmission scores. Prompt recognition of the route of cocaine use is vital to improve the outcome. Large-scale and well-designed observational studies are needed to investigate this topic further.

Does Performing Endoscopy Sooner Have an Impact on Outcomes in Patients With Acute Nonvariceal Upper Gastrointestinal Hemorrhage? A Systematic Review

Background

Endoscopy is the cornerstone for the diagnosis and treatment of nonvariceal upper gastrointestinal bleeding. Regarding the management of nonvariceal bleeding, the administration of crystalloid solution and proton pump inhibitors before endoscopy is well established, but the optimal timing of endoscopy has been a matter of debate and a subject of many investigational studies. The need for urgent endoscopy arises to provide prompt redress to acute bleeding, decrease the length of stay, and lower mortality from ongoing bleeding.

Objective

This study aimed to determine if endoscopy performed within 24 hours of presentation improves outcomes in terms of mortality, hospital length of stay, and rebleeding in individuals presenting with nonvariceal upper gastrointestinal bleed with any risk.

Methodology

We performed a systematic review of two large databases (PubMed and Google Scholar) to incorporate all studies published after 2000. We included studies with nonvariceal upper gastrointestinal bleeding and excluded those reporting variceal gastrointestinal hemorrhage.

Results

We reviewed eight studies that qualified after meeting our inclusion and exclusion criteria. We divided these studies into three separate groups based on the timing of endoscopy. Only two studies found a difference in mortality that was statistically significant in patients who underwent endoscopy within 24 hours of presentation. One study showed lower mortality in a patient who underwent urgent endoscopy, but it did not reach statistical significance. Other studies did not show any statistical difference in mortality, hospital length of stay, and rebleeding rates. The studies showed conflicting evidence on the amount of blood transfusion, though urgent endoscopy was found to be difficult in few studies due to blood obscuring the lesion.

Conclusions

While data suggest that there is a potential benefit in performing endoscopy sooner, there is no concrete evidence to point to a particular time range. Before performing endoscopy, the American Society for Gastrointestinal Endoscopy (2012) recommends adequate resuscitation with crystalloid solutions, blood transfusions, and antisecretory and prokinetic agent therapy. More investigational studies are needed to formulate a time-sensitive flow sheet to approach endoscopy in patients with nonvariceal upper gastrointestinal bleeding. A strict criterion is also needed to delineate patients into low-risk and high-risk groups. Doing so would provide a systematic approach to help with mortality, rebleeding, and healthcare resource utilization.

Encephalitis Associated With Hemophagocytic Lymphohistiocytosis Secondary to Immune Checkpoint Inhibitors: An Unfamiliar Spin-Off

Checkpoint inhibitors (CPI) have become mainstream in standard therapy in various tumors, especially in malignant melanoma. Despite their widespread beneficial effects, these inhibitors are also notorious for immune-related adverse events (irAEs). Hemophagocytic lymphohistiocytosis (HLH) is an aggressive and life-threatening syndrome of excessive immune activation. We report a case of a 33-year-old male having a history of metastatic melanoma on immunotherapy (status post two cycles of ipilimumab/nivolumab) admitted for persistent fever and elevated liver enzymes. Additional work showed anemia, thrombocytopenia, hypertriglyceridemia, and hyperferritinemia which meet the diagnostic criteria of histiocyte society HLH-2004. The patient was effectively treated with oral prednisone. Moreover, further complications encompassed slurred speech, word-finding difficulties, ataxia, and lower extremity hyperreflexia concerning for autoimmune encephalitis. He was treated with high-dose IV methylprednisolone (1 gram/day for 3 days) with improvement in symptoms. Autoimmune encephalitis associated with HLH can be fatal - high-dose IV methylprednisolone should be considered, but this avenue still needs to be explored.

Pravastatin-Induced Acute Pancreatitis: A Case Report and Literature Review

Pancreatitis is inflammation of pancreas associated most commonly with chronic alcoholism and gallstones. Other less common causes of pancreatitis are hyperlipidemia, infections, surgery, trauma, post endoscopic retrograde cholangiopancreatography, and drugs. Drugs are now increasingly recognized as a cause of pancreatitis, and high suspicion and exclusion of other most common causes is required before considering drug-induced pancreatitis. There are few case reports of acute pancreatitis in the literature after statin use, but out of these, only 3 are after starting pravastatin. We are reporting a case of 49-year-old male who presented with nausea, vomiting, and abdominal pain. His laboratory findings were significant for lipase more than 10 000 on admission, and computed tomography scan of abdomen was showing peripancreatic fat stranding and inflammation. After exclusion of most common causes of pancreatitis, pravastatin was found probable culprit for his symptoms, which he started taking 2 weeks ago. We also reviewed the literature on statins-induced acute pancreatitis. With increased uses of statins, physician need to be vigilant to suspect statins as a culprit in cases of pancreatitis with unknown etiology. Prompt discontinuation of statins is required in these cases.

Effect of hyperlipidemia in patients with a history of colon cancer

e15603

Background: The most common cancer of the digestive system is colorectal cancer. 5-year survival rate of early-stage colon cancer is > 90% whereas it is only 10% for patients with distant metastases. Recent studies have shown that lipids influence a tumor’s metastatic capabilities. High fat diet has also been linked with colon cancer. In this study, we try to understand the effect of hyperlipidemia in patients with a history of colon cancer. Methods: This is a retrospective study examining data from the National Inpatient Sample (NIS) Database of the year 2018. We identified patients with any history of Colon cancer using their specific ICD-10 codes. Additionally, we queried for ICD10 codes for hyperlipidemia. Primary outcome was inpatient mortality. Secondary outcome was hospital length of stay and total charge. Utilizing STATA MP 16.1 we performed multivariate logistic regression analysis. Various comorbidities including previous history of coronary artery disease, peripheral artery disease, stroke, smoking, diabetes, hypertension and chemotherapy were incorporated into the analysis. Additionally, hospital demographics were included in the analysis as well including race, hospital bed size teaching status, location, region, insurance and patient income. Data was considered statistically significant if p-value was < 0.05. Results: The total number of patients included in this study were 34,792. They were all adults age > 18 years. Approximately 49% were females. Mean age was 67 years and average hospital length of stay was 6.5 days. After running multivariable analysis for inpatient mortality, we noted that patients with hyperlipidemia had lower odds of mortality (Odds Ratio (OR) 0.64, 95% Confidence Intervals (CI) 0.56 – 0.73). Higher odds of mortality were seen in patients with coronary artery disease (OR 1.23, 95% CI 1.05 – 1.44). Among racial distributions, Blacks had higher odds of mortality when compared with White (OR 1.3, 95% CI 1.1 – 1.5). Hispanics had lower odds of inpatient mortality compared to Whites (OR 0.8, 95% CI 0.6 – 0.9). The odds of mortality were higher with increasing age (OR 1.025, 95% CI 1.02 – 1.031) and lower among females (0.82, 95% CI 0.73 – 0.91). Among secondary outcomes, hyperlipidemia did not affect the hospital length of stay or cost. Several factors increased the hospital length of stay which included any history of coronary artery disease, peripheral artery disease, or diabetes. In addition, patients admitted over the weekend had a higher length of stay. Conclusions: In this study, we find that hyperlipidemia is associated with lower mortality in patients with colon cancer. This could be possible because patients with hyperlipidemia are on statin therapy. This indirectly could point to a potential benefit of statins in colon cancer. Hyperlipidemia does not affect hospital length of stay or cost.

Effect of acute kidney injury on hospital-based outcomes in patients with multiple myeloma

e20006

Background: Multiple Myeloma, a cancer of plasma cells, is treatable, but incurable. 5-year survival rate is about 54% depending upon the stage. Studies have suggested that up to 50% of the patients experience acute kidney injury or chronic kidney disease at some point in their disease course. Approximately 3% of the patients will end up on hemodialysis. In this study we utilize the National Inpatient Sample (NIS) to understand the effect of acute kidney injury (AKI) on inpatient mortality in multiple myeloma patients. Methods: This is a retrospective study utilizing the data obtained from the NIS for the year 2018. We queried this NIS database for ICD-10 codes for multiple myeloma or plasmacytoma that had not achieved remission or was in relapse. We also looked at codes for acute kidney injury as secondary diagnosis. Primary outcome was inpatient mortality. Secondary outcomes were hospital length of stay and cost utilization. We then ran multivariate logistic regression analysis in STATA MP 16.1. Various comorbidities were accounted for by adding them into the analysis. These included previous history of coronary artery disease, congestive heart failure, stroke, smoking, hyperlipidemia, stem cell transplant, neutropenia and chemotherapy. Results: The population of multiple myeloma patients under investigation were all adults more than 18 years of age and numbered in 3944 patients. The mean age was 65.71 years. Among these 45% were females. While examining inpatient mortality we see that for patients that had AKI the odds of inpatient mortality are higher (Odds Ratio (OR) 1.75, p = 0.003, 95% Confidence Interval (CI) 1.21 – 2.56). History of Heart Failure (OR 2.28, 95% CI 1.59 – 3.28), and increasing age (OR 1.02, 95% CI 1.01 – 1.04) also appear to contribute towards higher odds of mortality. The effect of other comorbidities was not statistically significant. Among demographical characteristics being of Native American heritage or not belonging to any descriptive race predicted higher odds of mortality. Mean LOS was 11 days. Patients with AKI stayed in the hospital longer by ̃1.4 days (Coef. 1.39, 95% CI 0.41 – 2.37). LOS was higher in patients with a history of heart failure (2.61, 95% CI 0.89 – 4.34 and in those with a history of neutropenia (5.52, 95% CI 4.42 – 6.62). LOS was lower in patients with a history of smoking by 1 day. Age lowered the LOS by a clinically insignificant amount. Teaching hospitals had higher LOS by ̃4 days. The total charge for hospitalizations from AKI is higher by $31019 (95% CI 14444.23 – 47594.37). Other factors incurring higher cost include history of neutropenia, and teaching hospitals. Hospitals in the Midwest had lower cost compared to hospitals in the Northeast. Conclusions: Among patients that present with a principal diagnosis of multiple myeloma, having acute kidney injury, adversely affects inpatient outcomes that include, mortality, hospital length of stay and total hospitalization cost.

Analyzing the effects of depression among patients with head and neck cancer

e18038

Background: Patients with head and neck cancer carry the prospect of facial disfigurement in addition to the effects on speech, smell, sight, and taste. As such they are at a higher risk of acquiring emotional distress. Despite this, depression is underreported in this population. We review the National Inpatient Sample (NIS) to understand the effects of depression in patients admitted with any diagnosis of head and neck cancer. Methods: We designed a retrospective study and utilized NIS data for the year 2018. We identified patients with any history of Head and Neck cancer using their specific ICD-10 codes. We also identified codes for depressive disorders. Primary outcome was effect of depression on comorbidities. Secondary outcome was hospital length of stay. Utilizing STATA MP 16.1 we performed multivariate logistic regression analysis. Various comorbidities including previous history of coronary artery disease, congestive heart failure, stroke, smoking, hyperlipidemia, and chemotherapy were incorporated into the analysis. Results: The study population included 15,689 patients that were 18 years or older. Mean age was 64 years. Only 28% of the population was females. The mean hospital length of stay was approximately 7 days. In this group of patients, 12% had a history of depression. Among the different types of head and neck cancers oropharyngeal cancers had the highest percentage of depression rates (14%). In multivariable analysis, patients with depression had a higher comorbidity index but this result did not reach statistical significance (Odds Ratio (OR) 1.02, p = 0.054, 95% Confidence Intervals (CI) 0.999 – 1.045). Patients had higher odds of having depression if they also had a history of stroke (OR 1.4, 95% CI 1.13 – 1.73), prior history of chemotherapy (OR 1.25, 95% CI 1.09 – 1.43), history of hyperlipidemia (OR 1.31, 95% CI 1.16 – 1.48) or were admitted over the weekend (OR 1.21, 95% CI 1.07 – 1.38). Younger age was associated with lower odds of depression (OR 0.98, 95% CI 0.98 – 0.99). Women had higher odds of having depression (OR 1.68, 95% CI 1.51 – 1.88). When compared with white people, people from the following demographics had lower odds of depression – Black (OR 0.56, 95% CI 0.47 – 0.68), Hispanic (OR 0.64, 95% CI 0.49 – 0.83), Asian (OR 0.26, 95% CI 0.17 – 0.43), and others (OR 0.53, 95% CI 0.35 – 0.79). Hospital length of stay was higher among patients with depression (OR 0.7, 95% CI 0.2 – 1.15). Conclusions: Among patients with head and neck cancer, odds of having depression are higher in the white population, older patients, females and patients with prior history of chemotherapy. Depression is associated with higher hospital length of stay. These findings help understand the effect of depression on this susceptible population and identify at risk patients for appropriate screening.

Outcomes with COVID-19 in patients with hematopoietic stem cell transplant and cellular therapy: A systemic review and meta-analysis

e18611

Background: Coronavirus Disease 2019 (COVID-19) was declared a pandemic on March 11, 2020. COVID-19 has caused over 100 million infections and over 2 million deaths globally. Patients who have received a hematogenic stem cell transplant or cellular therapy (HCT) have a high risk of mortality and morbidity with COVID-19 due to severe immune dysregulation. We conducted a systematic review and meta-analysis aimed to evaluate the outcomes of COVID-19 in HCT patients. Methods: A literature search following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines (PRISMA) guidelines was performed on 3 databases (PubMed, Cochrane, and Clinical trials.gov) from the date of inception to Jan 2021. MeSH terms included ‘hematological malignancies’, ‘hematopoietic stem cell transplantation’, ‘SARS-CoV-2’, and ‘COVID 19’. We screened 99 articles and 6 studies (4 retrospective studies, 2 prospective) were included after excluding review, duplicate, and non-relevant articles. Quality evaluation was done using the NIH quality assessment tool. The Inter-study heterogeneity among the studies was assessed using the Q statistic proposed by Cochrane and the I2 index introduced by Higgins and Thompson. Pooled analysis was done using the ‘metaXL’, and the random effects model was used to estimate the pooled prevalence with 95% CI. Results: Of 1619 patients in 6studies, 646 HCT patients were analyzed (Table ). The median age of patients was 63 years and 59% were males. Median days since HCT for autologous (auto) HCT and allogeneic (allo) HCT patients were 690 and 450 days respectively. The average follow-up duration after COVID-19 was 24 days. COVID-19 mortality in HCT patients was 20% (95%CI 0.17 to 0.23, I2=0). Roedl et al (n=6) reported a mortality of 83% and was excluded from the pooled analysis. The mortality rate was 19% (95% CI 0.15 to 0.24, I2=0%) in auto HCT patients and 21% (95% CI 0.17 to 0.25, I2=0%) in allo HCT patients. Conclusions: The HCT patients are at significant risk of increased mortality and morbidity due to COVID-19. There is a need to prioritize HCT patients for COVID-19 vaccination, close surveillance, and aggressive management.[Table: see text]

Association of resolvin level in pregnant women with preeclampsia and metabolic syndrome

OBJECTIVE

Preeclampsia (PE) and Metabolic syndrome (MetS) are multifactorial conditions and are major causes of maternal and neonatal morbidity and mortality worldwide. Both conditions are pro-inflammatory and can be causative factor for vascular damage. Anti-inflammatory mediators such as Resolvin also called resolution-phase interaction products may help to reduce the effect. Therefore, this study aimed to measure the serum Resolvin level in mild pre-eclamptic women with and without metabolic syndrome.

MATERIAL AND METHODS

A total of 293 pregnant females were recruited in this case control study. They were grouped as: Group A [pre-eclamptic patients with MetS (n = 140)] and Group B [pre-eclamptic patients without MetS (n = 153)]. Preeclampsia was diagnosed according to the ACOG criteria and metabolic syndrome according the NCEP-ATP III guidelines. Anthropometric data, lipid profile, Resolvin, VEGFR and PlGF levels were tested as per manufacturer's guidelines. Data was analyzed by using SPSS version 23. In all instances, a p value of <0.05 was considered significant.

RESULTS

All females were aged matched so no difference was observed in any group. Blood pressure and triglyceride levels were significantly higher in Group A; whereas VEGFR and PlGF were lower as compared to Group B. Higher Resolvin levels were observed in Group A subjects as compared to Group B [105.19 ± 42.29 pg/ml; 46.74 ± 20.16 pg/ml; p < 0.01 respectively]. Resolvin levels were found to have a weak correlation with BMI (r = 0.264; p = 0.11), while a positive strong correlation with systolic BP (r = 0.722; p < 0.001), diastolic BP (r = 0.664; p < 0.001) and a negative correlation with VEGFR (r = -0.639; p < 0.01) and PlGF (r = -0.523; p < 0.01).

CONCLUSION

Higher resolvin levels were observed in PE subjects with metabolic syndrome and showed a significant strong positive correlation with blood pressure. Further longitudinal studies are required to identify the causal link.

Thrombotic Thrombocytopenic Purpura Induced by Immune Checkpoint Inhibitiors: A Case Report and Review of the Literature

In recent years, the role of immune checkpoint inhibitors (ICI) in cancer treatment has rapidly expanded. In randomized clinical trials, these agents have demonstrated clinical efficacy in extending survival and increasing response rates. Immune-related adverse effects (irAEs) involving various organs have been frequently narrated. Herein, we present a case report of thrombotic thrombocytopenic purpura (TTP) as a rare side effect of nivolumab, plus ipilimumab, in the treatment of metastatic renal cell carcinoma (RCC). A review of the literature for other case reports of TTP during treatment with ICIs was also performed. Our aim is to elucidate the significance of early recognition of this rare adverse effect in patients being treated with this relatively newer class of medications.

A Review of Interstitial Pneumonitis Caused by Elotuzumab Through Case Discussions and Academic Writings

Patients with relapsed or refractory multiple myeloma have undergone two or three previous therapies are now being treated with a humanized IgG1 monoclonal antibody elotuzumab (HuLuc63) that targets F7 signalling lymphocytic activation molecule F7 (SLAMF7)- a signalling lymphocytic activation molecule. It is combined with dexamethasone and lenalidomide/pomalidomide for therapy. Adverse effects associated with elotuzumab consists of peripheral neuropathy, fever, constitutional symptoms (fatigue, headache, decreased appetite), and infections. A rare side effect of interstitial lung disease has only been observed in a single case. There are two case studies presented below of hypoxic respiratory failure upon this monoclonal antibody treatment both were successfully treated with steroid therapy. This article brings forth the hypothesis that elotuzumab can cause pneumonitis, and discontinuation of elotuzumab along with high-dose corticosteroids helps reverse the pneumonitis.

Dual versus triple antithrombotic therapy: is there a role for direct oral anticoagulants in arterial thrombosis?

The number of patients receiving dual antiplatelet therapy with an additional indication for long-term oral anticoagulation has substantially increased over time. This population is facing an unacceptable risk of bleeding events, particularly among elderly individuals, who are especially vulnerable to complications. Further strategies to minimize this bleeding risk, including various drug combinations, different dosage regimens and even numerous attempts to find the appropriate duration of the treatment, have been evaluated in a multitude of randomized control trials. Moreover, the recent incorporation of the direct oral anticoagulants (DOACs) to the therapeutic armamentarium may represent an alternative to treat such patients, since they have demonstrated to be noninferior to the classic vitamin K antagonists and with lower bleeding rates. The aim of this review is to summarize the most recent literature on the use of DOACs in patients with an indication for dual antiplatelet therapy (mostly subjects with coronary artery disease) and also an established indication for chronic anticoagulation (chiefly individuals with nonvalvular atrial fibrillation). The role of DOACs in ischemic heart disease alone is also discussed.

Platelet function normalization after a prasugrel loading-dose: time-dependent effect of platelet supplementation

BACKGROUND

Hemostatic benefits of platelet transfusions in thienopyridine-treated acute coronary syndrome (ACS) patients may be compromised by residual metabolite in circulation.

OBJECTIVES

To estimate the earliest time after a prasugrel loading-dose when added platelets are no longer inhibited by prasugrel's active metabolite.

METHODS

Baseline platelet reactivity of healthy subjects (n=25, 30 ± 5 years, 68% male) on ASA 325 mg was tested using maximum platelet aggregation (MPA, ADP 20 μm) and VerifyNow(®) P2Y12 and was followed by a 60 mg prasugrel loading-dose. At 2, 6, 12 and 24 h post-dose, fresh concentrated platelets from untreated donors were added ex-vivo to subjects' blood, raising platelet counts by 0% (control), 40%, 60% and 80%. To estimate the earliest time when prasugrel's active metabolite's inhibitory effect on the added platelets ceases, platelet function in supplemented samples was compared across time-points to identify the time when effect of supplementation on platelet function stabilized (i.e. the increase in platelet reactivity was statistically similar to that at the next time-point).

RESULTS

Supplemented samples showed concentration-dependent increases in platelet reactivity vs. respective controls by both MPA and VerifyNow(®) at all assessment time-points. For each supplementation level, platelet reactivity showed a sharp increase from 2 to 6 h but was stable (P=NS) between 6 and 12 h.

CONCLUSIONS

The earliest measured time when supplemented platelets were not inhibited by circulating active metabolite of prasugrel was 6 h after a prasugrel loading-dose. These findings may have important implications for prasugrel-treated ACS patients requiring platelet transfusions during surgery.

Ovariectomy increases vascular calcification via the OPG/RANKL cytokine signalling pathway

BACKGROUND

Observational studies suggest a strong relationship between menopause and vascular calcification. Receptor activator of nuclear factor-kappaBeta ligand (RANKL) and osteoprotegerin (OPG) are critical regulators of bone remodelling and modulate vascular calcification. We assessed the hypothesis that ovariectomy increases vascular calcification via the OPG/RANKL axis.

MATERIALS AND METHODS

Age-matched sexually mature rabbits were randomized to ovariectomy (OVX, n = 12) or sham procedure (SHAM, n = 12). One month post-procedure, atherosclerosis was induced by 15 months 0.2%-cholesterol diet and endothelial balloon denudations (at months 1 and 3). Aortic atherosclerosis was assessed in vivo by magnetic resonance imaging (MRI) at months 9 and 15. At sacrifice, aortas were harvested for ex vivo microcomputed tomography (microCT) and molecular analysis of the vascular tissue.

RESULTS

Vascular calcification density and calcific particle number were significantly greater in OVX than SHAM (8.4 +/- 2.8 vs. 1.9 +/- 0.6 mg cm(-3), P = 0.042, and 94 +/- 26 vs. 33 +/- 7 particles cm(-3), P = 0.046, respectively). Calcification morphology, as assessed by the arc angle subtended by the largest calcific particle, showed no difference between groups (OVX 33 +/- 7 degrees vs. SHAM 33 +/- 5 degrees , P = 0.99). By Western blot analysis, OVX increased the vascular OPG:RANKL ratio by 66%, P = 0.029, primarily by decreasing RANKL (P = 0.019). At month 9, MRI demonstrated no difference in atheroma volume between OVX and SHAM, and no significant change was seen by the end of the study.

CONCLUSIONS

In contrast to bone, vascular OPG:RANKL ratio increased in response to ovariectomy with a corresponding fourfold increase in arterial calcification. This diametrical organ-specific response may explain the comorbid association of osteoporosis with calcifying atherosclerosis in post-menopausal women.

A novel anti-ischemic nitric oxide donor (LA419) reduces thrombogenesis in healthy human subjects

BACKGROUND

Platelet and endothelial production of nitric oxide (NO) is known to be impaired in coronary artery disease patients. Compounds that release NO (e.g. nitrates) have antiplatelet effects, but at supratherapeutic doses with hypotensive side effects.

OBJECTIVES

To investigate the antithrombotic effect on human blood of a novel NO donor (LA419) with known anti-ischemic properties but without hypotensive side effects and to compare with abciximab.

PATIENTS/METHODS

Healthy subjects (n = 8; 32 +/- 3 years) received daily aspirin starting three days prior to the study day. Treatments (LA419 10 and 20 microm, and abciximab 4 microm) were added ex vivo to non-anticoagulated blood, and the antithrombotic properties were assessed by measuring changes in thrombus size from pretreatment baseline in the Badimon perfusion chamber at low and high shear rates. Platelet surface adhesion using a Cone and Platelet Analyzer (CPA) and platelet fibrinogen-receptor activation with flow cytometry were also evaluated.

RESULTS

At low shear rates, LA419 displayed a reduction in thrombus area of 43% +/- 8% (10 microm) and 56% +/- 6% (20 microm), whereas at high shear rates the reductions were 44% +/- 3% (10 microm) and 62% +/- 6% (20 microm). Platelet surface adhesion with the CPA was also reduced. Abciximab exhibited a strong inhibitory effect on thrombus formation, platelet surface adhesion and fibrinogen receptor activation.

CONCLUSIONS

The novel NO donor, LA419, shows a strong antithrombotic effect in human blood, which is comparable to abciximab, especially under high shear rate conditions. Our observations suggest that the availability of an NO donor could prove beneficial in the prevention of thrombotic complications of cardiovascular disease. Further clinical studies are warranted.

Normalization of platelet reactivity in clopidogrel-treated subjects

BACKGROUND

Aspirin (ASA) + clopidogrel are commonly used in acute coronary syndrome (ACS), but persistent antiplatelet effects may complicate surgery.

METHODS AND RESULTS

To study the possibility of normalizing platelet reactivity after ASA + clopidogrel treatment, 11 healthy subjects received a 325-mg ASA + clopidogrel loading dose (300 or 600 mg dependent on study arm), followed by 81 mg of ASA + 75 mg of clopidogrel daily for 2 days. Platelet reactivity was assessed by light transmittance aggregometry (LTA) [challenged by adenosine diphosphate (ADP), arachidonic acid (AA), collagen, and thrombin receptor activating peptide (TRAP)] and flow cytometry for platelet activation by GPIIb/IIIa receptor exposure pretreatment, 4 and 72 h postload. To normalize platelet reactivity, increasing amounts of pooled platelets from five untreated volunteers [volunteers (V)-platelet-rich plasma (PRP)] were added ex vivo to the subject's PRP (S-PRP). At both 4 and 72 h, 40% and 50% V-PRP were needed to overcome platelet disaggregation in the 300 or 600 mg arms, respectively, after ADP challenge; an additional 10% V-PRP fully normalized aggregation. Recovery of function was linear with each incremental increase of V-PRP. ADP-induced GPIIb/IIIa activation showed the same pattern as LTA (r = 0.74). Forty percent V-PRP was required to normalize platelet function to AA, collagen, and TRAP.

CONCLUSION

Our results suggest that the pre-operative transfusion of 10 platelet concentrate units (the equivalent of 40% V-PRP) after a 300-mg clopidogrel loading or 12.5 units (50% V-PRP) after a 600 mg loading may adequately reverse clopidogrel-induced platelet disaggregation to facilitate postoperative hemostasis. An additional 2.5 units fully normalized platelet function. The potential clinical implications of our observations could include shorter hospitalizations and reduced bleeding complications. But these observations should be fully explored in an in vivo clinical setting with clopidogrel-treated patients before and after surgery.