Platelet aggregation and coagulation factors in orthopedic surgery.

Hemostasis is a major concern during the perioperative period. Changes in platelet aggregation and coagulation factors may contribute to the delicate balance between thrombosis and bleeding. We sought to better understand perioperative hemostasis by investigating the changes in platelet aggregation and coagulation factors during the perioperative period. We performed a prospective cohort analysis of 70 subjects undergoing non-emergent orthopedic surgery of the knee (n = 28), hip (n = 35), or spine (n = 7) between August 2011 and November 2011. Plasma was collected preoperatively (T1), 1-h intraoperatively (T2), 1-h (T3), 24-h (T4) and 48-h (T5) postoperatively. Platelet function testing was performed using whole blood impedance aggregometry. Coagulation assays were performed for factor VII, factor VIII, von Willebrand Factor (vWF), and fibrinogen. Of the 70 patients, mean age was 64.1 ± 9.8 years, 61% were female, and 74% were Caucasian. Platelet activity decreased until 1 h postoperatively and then significantly increased above baseline at 24- and 48-h postoperatively. Compared to baseline, coagulation factors decreased intraoperatively. Factor VII activity continued to decrease, while FVIII, vWF, and fibrinogen all increased above baseline postoperatively. The results of our study indicate significant changes in platelet activity and coagulation factors during the perioperative period. Both platelet activity and markers of coagulation decrease during the intraoperative period and then some increase postoperatively. These changes may contribute to the hypercoagulabity and/or bleeding risk that occurs in the perioperative period. Future prospective studies aimed at correlating hemostatic changes with perioperative outcomes are warranted.

Thrombotic and bleeding complications after orthopedic surgery.

BACKGROUND: Thrombotic and bleeding complications are major concerns during orthopedic surgery. Given the frequency of orthopedic surgical procedures and the limited data in the literature, we sought to investigate the incidence and risk factors for thrombotic (myocardial necrosis and infarction) and bleeding events in patients undergoing orthopedic surgery. METHODS AND RESULTS: We performed a retrospective cohort analysis of 3,082 consecutive subjects ≥21 years of age undergoing hip, knee, or spine surgery between November 1, 2008, and December 31, 2009. Patient characteristics were ascertained using International Classification of Diseases, Ninth Revision, diagnosis coding and retrospective review of medical records, and laboratory/blood bank databases. In-hospital outcomes included myocardial necrosis (elevated troponin), major bleeding, coded myocardial infarction, and coded hemorrhage as defined by International Classification of Diseases, Ninth Revision, coding. Of the 3,082 subjects, mean age was 60.8 ± 13.3 years, and 59% were female. Myocardial necrosis, coded myocardial infarction, major bleeding, and coded hemorrhage occurred in 179 (5.8%), 20 (0.7%), 165 (5.4%), and 26 (0.8%) subjects, respectively. Increasing age (P < .001), coronary artery disease (P < .001), cancer (P = .004), and chronic kidney disease (P = .01) were independent predictors of myocardial necrosis, whereas procedure type (P < .001), cancer (P < .001), female sex (P < .001), coronary artery disease (P < .001), and chronic obstructive pulmonary disease (P = .01) were independent predictors of major bleeding. CONCLUSION: There is a delicate balance between thrombotic and bleeding events in the perioperative period after orthopedic surgery. Perioperative risk of both thrombosis and bleeding deserves careful attention in preoperative evaluation, and future prospective studies aimed at attenuating this risk are warranted.

Association Between Anemia, Bleeding, and Transfusion with Long-term Mortality Following Noncardiac Surgery.

BACKGROUND: Preoperative anemia is a well-established risk factor for short-term mortality in patients undergoing noncardiac surgery, but appropriate thresholds for transfusion remain uncertain. The objective of this study was to determine long-term outcomes associated with anemia, hemorrhage, and red blood cell transfusion in patients undergoing noncardiac surgery. METHODS: We performed a long-term follow-up study of consecutive subjects undergoing hip, knee, and spine surgery between November 1, 2008 and December 31, 2009. Clinical data were obtained from administrative and laboratory databases, and retrospective record review. Preoperative anemia was defined as baseline hemoglobin < 13 g/dL for men and < 12 g/dL for women. Hemorrhage was defined by International Classification of Diseases, Ninth Revision coding. Data on long-term survival were collected from the Social Security Death Index database. Logistic regression models were used to identify factors associated with long-term mortality. RESULTS: There were 3050 subjects who underwent orthopedic surgery. Preoperative anemia was present in 17.6% (537) of subjects, hemorrhage occurred in 33 (1%), and 766 (25%) received at least one red blood cell transfusion. Over 9015 patient-years of follow-up, 111 deaths occurred. Anemia (hazard ratio [HR] 3.91; confidence interval [CI], 2.49-6.15) and hemorrhage (HR 5.28; 95% CI, 2.20-12.67) were independently associated with long-term mortality after multivariable adjustment. Red blood cell transfusion during the surgical hospitalization was associated with long-term mortality (HR 3.96; 95% CI, 2.47-6.34), which was attenuated by severity of anemia (no anemia [HR 4.39], mild anemia [HR 2.27], and moderate/severe anemia [HR 0.81]; P for trend .0015). CONCLUSIONS: Preoperative anemia, perioperative bleeding, and red blood cell transfusion are associated with increased mortality at long-term follow-up after noncardiac surgery. Strategies to minimize anemia and bleeding should be considered for all patients, and restrictive transfusion strategies may be advisable. Further investigation into mechanisms of these adverse events is warranted.

Perioperative antiplatelet therapy and cardiovascular outcomes in patients undergoing joint and spine surgery.

STUDY OBJECTIVE: Perioperative thrombotic complications after orthopedic surgery are associated with significant morbidity and mortality. The use of aspirin to reduce perioperative cardiovascular complications in certain high-risk cohorts remains controversial. Few studies have addressed aspirin use, bleeding, and cardiovascular outcomes among high-risk patients undergoing joint and spine surgery. DESIGN/SETTING/PATIENTS: We performed a retrospective comparison of adults undergoing knee, hip, or spine surgery at a tertiary care center during 2 periods between November 2008 and December 2009 (reference period) and between April 2013 and December 2013 (contemporary period). MEASUREMENTS: Patient demographics, comorbidities, management, and outcomes were ascertained using hospital datasets. MAIN RESULTS: A total of 5690 participants underwent 3075 joint and spine surgeries in the reference period and 2791 surgeries in the contemporary period. Mean age was 61±13 years, and 59% were female. In the overall population, incidence of myocardial injury (3.1% vs 5.8%, P<.0001), hemorrhage (0.2% vs 0.8%, P=.0009), and red blood cell transfusion (17.2% vs 24.8%, P<.001) were lower in the contemporary period. Among 614 participants with a preoperative diagnosis of coronary artery disease (CAD), in-hospital aspirin use was significantly higher in the contemporary period (66% vs 30.7%, P<.0001); numerically, fewer participants developed myocardial injury (13.5% vs 19.3%, P=.05), had hemorrhage (0.3% vs 2.1%, P=.0009), and had red blood cell transfusion (37.2% vs 44.2%, P<.001) in the contemporary vs reference period. CONCLUSIONS: In a large tertiary care center, the incidence of perioperative bleeding and cardiovascular events decreased over time. In participants with CAD, perioperative aspirin use increased and appears to be safe.

Relation of perioperative elevation of troponin to long-term mortality after orthopedic surgery.

Myocardial necrosis in the perioperative period of noncardiac surgery is associated with short-term mortality, but long-term outcomes have not been characterized. We investigated the association between perioperative troponin elevation and long-term mortality in a retrospective study of consecutive subjects who underwent hip, knee, and spine surgery. Perioperative myocardial necrosis and International Classification of Disease, Ninth Revision-coded myocardial infarction (MI) were recorded. Long-term survival was assessed using the Social Security Death Index database. Logistic regression models were used to identify independent predictors of long-term mortality. A total of 3,050 subjects underwent surgery. Mean age was 60.8 years, and 59% were women. Postoperative troponin was measured in 1,055 subjects (34.6%). Myocardial necrosis occurred in 179 cases (5.9%), and MI was coded in 20 (0.7%). Over 9,015 patient-years of follow-up, 111 deaths (3.6%) occurred. Long-term mortality was 16.8% in subjects with myocardial necrosis and 5.8% with a troponin in the normal range. Perioperative troponin elevation (hazard ratio 2.33, 95% confidence interval 1.33 to 4.10) and coded postoperative MI (adjusted hazard ratio 3.51, 95% confidence interval 1.44 to 8.53) were significantly associated with long-term mortality after multivariable adjustment. After excluding patients with coronary artery disease and renal dysfunction, myocardial necrosis remained associated with long-term mortality. In conclusion, postoperative myocardial necrosis is common after orthopedic surgery. Myocardial necrosis is independently associated with long-term mortality at 3 years and may be used to identify patients at higher risk for events who may benefit from aggressive management of cardiovascular risk factors.

Minimal change disease and IgA deposition: separate entities or common pathophysiology?

Introduction. Minimal Change Disease (MCD) is the most common cause of nephrotic syndrome in children, while IgA nephropathy is the most common cause of glomerulonephritis worldwide. MCD is responsive to glucocorticoids, while the role of steroids in IgA nephropathy remains unclear. We describe a case of two distinct clinical and pathological findings, raising the question of whether MCD and IgA nephropathy are separate entities or if there is a common pathophysiology. Case Report. A 19-year old man with no medical history presented to the Emergency Department with a 20-day history of anasarca and frothy urine, BUN 68 mg/dL, Cr 2.3 mg/dL, urinalysis 3+ RBCs, 3+ protein, and urine protein : creatinine ratio 6.4. Renal biopsy revealed hypertrophic podocytes on light microscopy, podocyte foot process effacement on electron microscopy, and immunofluorescent mesangial staining for IgA. The patient was started on prednisone and exhibited dramatic improvement. Discussion. MCD typically has an overwhelming improvement with glucocorticoids, while the resolution of IgA nephropathy is rare. Our patient presented with MCD with the uncharacteristic finding of hematuria. Given the improvement with glucocorticoids, we raise the question of whether there is a shared pathophysiologic component of these two distinct clinical diseases that represents a clinical variant.