Impact Of Perioperative Use Research Articles

How do the top 10 known offending drug classes associated with decreased bone mineral density affect total shoulder arthroplasty outcomes?

Many regularly prescribed classes of drugs are known to negatively impact bone health. However, it is unclear if perioperative use of these drugs impacts total shoulder arthroplasty (TSA) outcomes. The purpose of this study was to analyze the impact of perioperative use of 10 drug classes with known negative effects on bone health on prosthesis-related outcomes of TSA. Patients who underwent primary TSA were retrospectively identified in the PearlDiver database. Within this population, patients prescribed proton pump inhibitors (PPIs), thiazolidinediones (TZDs), loop diuretics, glucocorticoids, aromatase inhibitors, calcineurin inhibitors, selective serotonin reuptake inhibitors (SSRIs), antiepileptic drugs (AEDs), first-generation antipsychotics (FGAs), and second-generation antipsychotics (SGAs) within 6 months before or 6 months after primary TSA were identified (n=23,748). These patients were propensity score matched 1:1 with controls (n=23,748) on age, sex, and several comorbidities. After matching, patients with perioperative drug exposure were divided into 10 subgroups (ie, 1 for each drug class). Rates of prosthesis-related complications among patients taking each medication class vs. controls were compared with multivariable logistic regression. Relative to controls, SGA exposure was associated with significantly higher rates of all-cause revision (odds ratio [OR] 1.68) and aseptic revision (OR 1.57). Loop diuretic exposure was associated with significantly higher rates of all-cause revision (OR 1.44) and aseptic revision (OR 1.43). Glucocorticoid exposure was associated with significantly higher rates of all-cause revision (OR 1.32) and aseptic revision (OR 1.30). SSRI exposure was associated with significantly higher rates of all-cause revision (OR 1.27) and aseptic revision (OR 1.24). Periprosthetic fracture, aseptic loosening, and septic revision was comparable for all drug cohorts compared to matched controls (all P>.05). Patients with perioperative exposure to PPIs, TZDs, FGAs, AEDs, aromatase inhibitors, and calcineurin inhibitors displayed comparable rates of all queried complications compared with controls (all P>.05). Compared with matched controls, patients with perioperative exposure to SGAs, loop diuretics, glucocorticoids and SSRIs exhibited significantly higher rates of all-cause and aseptic revisions following primary TSA. Several other medications that are risk factors for osteoporosis and fragility fractures did not demonstrate significant associations with any complications, including periprosthetic fracture. These results highlight the need for a thorough review of patients' medical history and current medication usage prior to preoperative risk counseling for patients seeking TSA.

The Impact of Perioperative Use of Nonbiologic Disease-Modifying Anti-rheumatic Drugs on Perioperative Blood Loss and Complications in Patients Who Have Rheumatoid Arthritis Undergoing Total Knee Arthroplasty

BackgroundThe use of disease-modifying antirheumatic drugs (DMARDs) before total knee arthroplasty (TKA) was associated with increased risk of postoperative periprosthetic joint and wound infections as well as worse platelet function in patients who have knee rheumatoid arthritis (RA). This study investigated the effects of DMARDS on perioperative blood loss, complications, and blood transfusion in patients undergoing TKA for knee RA. MethodsWe retrospectively enrolled patients undergoing TKA for knee RA at our hospital between 2017 and 2021 who received DMARDs (n = 73) or not (n = 84). Every RA patient was matched with patients who had osteoarthritis (OA) in a ratio of 1:1 or 1:2. Primary outcomes were intraoperative and perioperative blood losses, while secondary outcomes were complications and allogeneic transfusions. ResultsThe mean total (804 versus 728 mL (mL), P = .114), mean intraoperative (113 versus 101 mL, P = .488), or hidden blood losses (705 versus 640 mL, P = .340) did not differ statistically between RA patients who received DMARDs versus those who did not. RA patients who received DMARDs showed significantly greater mean total (804 versus 654 mL, P = .001), intraoperative (113 versus 75 mL, P = .002), and hidden blood losses (705 versus 560 mL, P = .016) than OA patients. No statistical differences were found in complications or allogeneic transfusions. ConclusionAlthough RA patients experienced greater perioperative blood loss than OA patients, there was no statistical difference in perioperative blood loss, complications, or allogeneic transfusions between RA patients who received DMARDs and those who did not.

Perioperative use of NSAIDs and the risk of short-term endoscopic recurrence in Crohn's disease patients: A retrospective cohort study

BackgroundMore evidence is needed on the use of NSAID based postoperative pain regimens for Crohn's disease (CD) and its association with recurrence. Our goal is to assess the impact of perioperative use of NSAIDs on endoscopic disease recurrence in patients with CD. MethodsA retrospective cohort study was conducted. The primary outcome measured was endoscopic disease recurrence within 24 months of surgery, defined as a Rutgeerts score ≥ i2. ResultsWe identified 107 patients with CD that underwent index ileocolectomy with primary anastomosis between January 2009 and July 2019. Endoscopic disease recurrence was identified in 28 (26.2%) and clinical recurrence in 18 (16.8%) patients. Exposure to NSAIDs did not increase 24-month endoscopic recurrence risk (22.2% vs. 38.5% patients, p = 0.12). ConclusionIn patients with CD undergoing elective ileocolic resection and primary ileocolic anastomosis, NSAID use in the perioperative period did not impact endoscopic or clinical disease recurrence rate.

Opioid Receptor Expression in Colorectal Cancer: A Nested Matched Case-Control Study.

BackgroundThere is growing interest in the possible effect of perioperative anesthetic management on the growth and spread of cancer. The impact of perioperative use of opioids on cancer recurrence remains controversial and an assessment cannot yet be established based on current publications. This study aimed to assess the differential expression of opioid receptors between healthy and tumor tissues in patients with stage II and III colorectal cancer undergoing elective surgery by immunohistochemistry (IHC).MethodsPropensity–score matched case–control study nested in a retrospective cohort of patients with stage II or III colorectal. The primary endpoint was the difference in µ–opioid receptor (MOR) expression measured by IHC between tumor and healthy tissue in subject with or without recurrence. Secondary endpoints were to evaluate the differences in Opioid Growth Factor Receptor (OGFR), cyclic adenosine monophosphate (cAMP) production and protein kinase A (PKA) in the matched sample and from a from samples of colorectal cancer stored in the Cancer Genome Atlas (TCGA) and Genotype Tissue Expression Project (GTEx).ResultsThere was a significant difference in MOR receptor (median 3 [intequartile range IQR: 1–3] and 0 [IQR: 0–2], P<0.001) and OGFR receptor (median 6 [IQR: 5–6] and 2 [IQR: 1–2], P<0.001) in tumor and control tissue respectively. However, there were no significant differences in cAMP nor PKA expression between both types of tissues and in expression in any of the analyzed variables by recurrence status. The MOR and OGFR expression data from TCGA database were similar to our sample size data with lower expression of MOR and higher expression of OGFR in tumoural samples with a skewed distribution for MOR expression in tumor tissue both in patients with and without recurrence.ConclusionIn patients with stage II and III colorectal cancer, overall expression of MOR and OGFR was significantly increased but was not different between previously matched patients with or without recurrence. No differences were found in the analyzed metabolic pathway of cAMP–PKA: These results were confirmed by an in silico analysis of samples from the TCGA–GTEx database.

Impact of perioperative use of GnRH agonist or dienogest on ovarian reserve after cystectomy for endometriomas: a randomized controlled trial

BackgroundOvarian endometrioma is a common gynecological disease that is often treated with surgery or hormonal treatment. Ovarian cystectomy, a surgical procedure for ovarian endometrioma, can result in impaired ovarian reserve.MethodsWe conducted a randomized controlled trial to evaluate the efficacy of hormonal treatment [gonadotropin-releasing hormone agonist (GnRHa) or dienogest (DNG)] for preserving ovarian reserve after cystectomy for ovarian endometrioma. The primary endpoint was the level of serum Anti-Müllerian hormone (AMH) as a marker of ovarian reserve.ResultsBefore and after laparoscopic surgery, 22 patients in the GnRHa group and 27 patients in the DNG group were administered hormonal treatment for a total of 4 months. After 1-year follow-up, >60% of the patients in the DNG group retained over 70% of their pretreatment AMH levels, whereas no patient in the GnRHa group retained their AMH levels after cystectomy (P < 0.01). Interleukin-6 (IL-6) is a key cytokine involved in inflammation. Compared with the GnRHa group, patients in the DNG group had lower IL-6 levels at the end of treatment.ConclusionsOur data revealed that DNG is more effective than GnRHa in preserving ovarian reserve after cystectomy of ovarian endometrioma. This is achieved through the reduction of the inflammatory response during the perioperative period and other endometriosis-related inflammatory reactions.Trial registrationThe registration number of this trial is UMIN-CTR, UMIN000018569, registered 6 August 2015, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000021492, and Japan Registry of Clinical Trials, jRCTs041180140, registered 29 March 2019, https://jrct.niph.go.jp/en-latest-detail/jRCTs041180140. This randomized controlled trial was conducted in accordance with the CONSORT guidelines.

Effects of antihypertensive drugs on surgical outcomes of breast reconstruction: a nationwide population-based claim study.

Experimental studies have reported that angiotensin receptor blockers (ARBs) increase the risk of surgical complications. However, clinical data on their effect on surgical outcomes are limited. The aim of this study was to investigate the impact of perioperative use of ARBs on the outcomes of breast reconstruction using population-based claim data. Data of patients who underwent direct-to-implant or abdomen-based autologous breast reconstruction after total mastectomy from April 2015 to December 2018 were obtained from the Health Insurance Review and Assessment Service database. The patients were categorized as ARB, non-ARB, control, and non-hypertension groups. The effects of ARBs on surgical complications, length of hospital stay, and complication-related medical costs were evaluated. Of the 9,036 patients who met the inclusion criteria, 5,192 underwent direct-to-implant reconstruction, and 3,844 underwent abdomen-based autologous reconstruction. The length of hospital stay was the longest and the surgical complication rate and complication-related medical cost were the highest in the ARB group after both reconstruction methods. Compared with non-treatment with antihypertensive drugs, ARB use was found to be an independent risk factor for surgical complications in direct-to-implant reconstruction [odds ratio (OR), 1.96; 95% confidence interval (CI), 1.09-3.50; P=0.0237] and complication-related medical cost (OR, 1.93; 95% CI, 1.10-3.40; P=0.0221) in abdomen-based autologous reconstruction. Perioperative ARB use was associated with adverse postoperative breast reconstruction outcomes. These findings might have a significant impact on perioperative antihypertensive management; nevertheless, further studies are warranted to confirm the study findings.

Perioperative Beta-Blocker for Atrial Fibrillation after Cardiac Surgery: A Meta-Analysis.

This meta-analysis was conducted to evaluate the impact of perioperative use of beta-blocker (BB) on postoperative atrial fibrillation (POAF) after cardiac surgery other than isolated coronary artery bypass grafting (CABG). Five online databases were searched. Studies were included if they (1) enrolled patients who underwent cardiac surgery other than isolated CABG and (2) demonstrated the impact of perioperative use of BB on POAF based on the randomized controlled trial or adjusted analysis. The primary outcome was the occurrence rates of POAF after cardiac surgery. A meta-regression and subgroup analysis were performed according to the proportion of patients with cardiac surgery other than isolated CABG and the timing of BB use, respectively. Thirteen articles (5 randomized and 8 nonrandomized studies: n = 25,496) were selected. Proportion of enrolled patients undergoing cardiac surgery other than isolated CABG ranged from 7 to 100%. The BBs were used in preoperative, postoperative, and both periods in 5, 5, and 3 studies, respectively. The pooled analyses showed that the risk of POAF was significantly lower in patients with perioperative BB than those without (odds ratio, 95% confidence interval = 0.56, 0.35-0.91 and 0.70, 0.55-0.91 in randomized and nonrandomized studies, respectively). The risk of POAF was lower in the BB group irrespective of the proportion of nonisolated CABG. Benefit regarding in-hospital mortality was inconclusive. Perioperative stroke and length of stay were not significantly different between BB and non-BB groups. Perioperative use of BB is effective in preventing POAF even in patients undergoing cardiac surgery other than isolated CABG, although it did not translate into improved clinical outcomes.

The Impact of Perioperative Use of a Statin-Magnesium Combination on Opioid Consumption in Patients Who Underwent Cardiac Surgery: A Retrospective Study with Propensity-Score Matching.

Both statins and magnesium are associated with NMDA receptors and anti-inflammatory effect. Peripheral NMDA receptors are known to be involved in inflammation-induced pain. This study aimed to investigate the impact of perioperative use of a statin–magnesium combination on opioid consumption in patients who underwent cardiac surgery. This was a retrospective study of 542 patients who underwent cardiac surgery. The patients were divided into two groups according to statin use: the statin–magnesium group (n=375) and the magnesium-only group (n=167). Patients in the magnesium-only group received only perioperative magnesium, but no statins, to prevent atrial fibrillation following cardiac surgery. After propensity-score matching, 228 patients (n=114 in each group) were analyzed to investigate opioid consumption, visual analogue scale (VAS) pain scores over a 72-h period, and pain outcomes according to the duration of statin treatment (<1 or ≥1 yr). The consumed opioid volume was significantly smaller in statin–magnesium group than the magnesium-only group, both before (p=0.010) and after matching (p=0.017). The statin–magnesium combination did not significantly reduce the VAS pain scores compared with magnesium alone. Although the statin–magnesium combination did not significantly reduce the pain intensity compared with magnesium alone, the combination therapy was effective in reducing opioid consumption after surgery.

Perioperative use of cefazolin ameliorates postoperative cognitive dysfunction but induces gut inflammation in mice

BackgroundEmerging evidence indicates that long-time use of multiple antibiotics can induce cognitive dysfunction via gut dysbiosis. Cefazolin is often used for 3 to 5 days to prevent perioperative infection. This study is to detect the impact of perioperative use of cefazolin on inflammatory responses and postoperative cognition.MethodsThe anti-inflammatory effect of cefazolin was determined in mouse C8-B4 microglial cells treated with lipopolysaccharide (LPS). Interleukin (IL)-6 and IL-1β at 6 and 24 h after LPS treatment were detected. Six- to 8-week-old CD-1 mice were subjected to laparotomy. Cefazolin at 300 mg/kg was injected intraperitoneally 1 h before surgery and then once per day for 5 days after surgery. Their learning and memory were assessed by Barnes maze and fear conditioning tests which started 1 week after the surgery. The brain and colon were harvested 24 h and 6 days after surgery to determine inflammatory cytokines. The colon and its luminal contents were harvested 6 and 19 days after surgery for the determination of bacteria flora. Cefazolin concentrations in the serum and brain were measured 0.5, 1, and 2 h after cefazolin injection.ResultsIL-6 and IL-1β levels were decreased by 250 μg/ml cefazolin in the LPS-stimulated C8-B4 cells. Laparotomy increased the time for mice to identify the target hole in the Barnes maze on day 1 and day 8 after training sessions and reduced context-related freezing behavior in fear conditioning test. Cefazolin attenuated these surgical effects but reduced context-related freezing behavior in mice without surgery. IL-6 in the hippocampus and cerebral cortex, IL-1β in the cerebral cortex, and IL-6 and IL-1β in the serum and colon were increased 24 h after laparotomy. Cefazolin attenuated these effects. Cefazolin treatment for 5 days in mice without surgery induced colon dysbiosis and increased IL-6 and IL-1β in the colon and IL-1β in the cerebral cortex. Colon dysbiosis disappeared in mice treated with cefazolin alone but persisted in mice with surgery and cefazolin 19 days after surgery. High cefazolin concentrations in the serum but not in the brain were detected after cefazolin injection.ConclusionsThese results suggest that cefazolin has a direct anti-inflammatory effect and can attenuate surgery-induced postoperative memory and learning impairment in mice. Cefazolin alone may induce cognitive dysfunction possibly by transient gut dysbiosis in mice without surgery.

Impact of antithrombotic treatment on clinical outcomes after craniotomy for unruptured intracranial aneurysm

ObjectivePatients receiving antithrombotic treatment occasionally undergo craniotomy. We aimed to explore the impact of perioperative use of antithrombotic agents on the occurrence of surgical complications and clinical outcomes in patients with unruptured intracranial aneurysm (UIA). Patients and methodsWe retrospectively analyzed 401 consecutive patients who had undergone craniotomy for UIA at our institution between January 2006 and December 2016. Patients were divided into two groups: those who received oral antiplatelet and/or anticoagulant agents during the perioperative period (antithrombotic treatment group, n=45); and those who did not (no antithrombotic treatment group, n=356). In the antithrombotic treatment group, 40 patients received antiplatelet alone, 2 received anticoagulant alone, and 3 received antiplatelet plus anticoagulant. ResultsThe two groups showed no significant differences in mortality, morbidity, or occurrence of symptomatic brain infarction, but intracranial hemorrhage was more frequent in the antithrombotic treatment group than in the no antithrombotic treatment group (p=0.0187). Multivariate analysis revealed posterior location of the aneurysm (odds ratio (OR), 8.10; 95% confidence interval (CI), 2.77-23.68; p=0.0001) and surgical procedure (OR, 5.48; 95%CI, 1.68-17.86; p=0.0048) as significantly correlated with severe morbidity, and intracranial hemorrhage as correlated significantly with antithrombotic treatment (OR, 3.83; 95%CI, 1.36-10.76; p=0.0110). ConclusionsThis study provides important information about the occurrence of intracranial hemorrhage and clinical outcomes in patients undergoing antithrombotic treatment during the perioperative period of craniotomy for UIA.

Atrial fibrillation following aortic valve replacement: impact of perioperative use of intravenous β-blocker.

Despite recent advances in perioperative management, postoperative atrial fibrillation/flutter (POAF) remains the most common complication after cardiac surgery. Therefore, it is important to determine related risk factors to establish effective management. However, most studies have focused on patients undergoing coronary artery bypass grafting and little is known about POAF in those who receive aortic valve replacement (AVR). We investigated the relationship of clinical predictors with POAF in patients undergoing AVR. A total of 119 patients who underwent AVR were enrolled in this study, and the relationships between POAF incidence and perioperative (preoperative, operative, postoperative) factors were examined. POAF occurred in 47 patients (40%). In univariate analysis, older age was significantly associated with POAF occurrence, which was significantly related to prolonged intensive care unit (ICU) stay and postoperative stroke. It also showed patients with preoperative β-blocker experienced POAF less frequently than those without β-blocker. Multivariate analysis showed that preoperative β-blocker usage was an independent predictor of POAF. In patients who received both preoperative oral and postoperative intravenous β-blocker administrations, the incidence of POAF was reduced to 14% (3/22). POAF frequently occurred in patients undergoing AVR, and was significantly related to prolonged ICU stay and postoperative stroke. Our findings show that advanced age and absence of preoperative β-blocker usage are risk factors for POAF. Furthermore, in patients undergoing AVR, perioperative intravenous β-blocker administration may be useful for prevention.

P048 In vitro pancreas toxicity by azathioprine but not 6-mercaptopurine

BACKGROUND: The impact of perioperative use of anti-TNFα on post-operative complications such as infection and wound healing is controversial. There are few studies that reveal relationship between pre-operative serum anti-TNFα concentration and post-operative outcomes in inflammatory bowel diseases. Moreover, perioperative change in serum concentration of anti-TNFα remains to be defined. PURPOSE: The current study assessed perioperative change in serum infliximab concentration of inflammatory bowel diseases and its impact on post-operative surgical site infection (SSI). METHODS: This observation study enrolled 22 ulcerative colitis (UC) and 22 Crohn's disease (CD) patients between January 2010 and October 2013. Patients underwent bowel resections within 8 weeks of last infliximab infusion. Serum samples were collected just before and after surgery, infliximab concentration of each sample was determined by an enzyme-linked immunosorbent assay. The relationships between these concentrations and post-operative SSIs were evaluated. RESULTS: Pre-operative serum infliximab were detected in 12 UC patients (54.5%) and 19 CD patients (86.4%). In UC patients who were detected pre-operative serum infliximab (cut-off value<1.0μg/ dL), there was no significant change from mean pre-operative infliximab concentration (6.20±4.56μg/dL) to post-operative infliximab concentration (5.03±3.88μg/dL) (-18.9%, p= 0.45). On the other hand, in CD patients who were detected pre-operative serum infliximab, there was a significant reduction from pre-operative concentration (5.63±22.5μg/dL) to postoperative concentration (3.93±3.65μg/dL) (-30.2%, p<0.01). SSIs occurred in 4 (19.4%) UC and 6 (27.3%) CD patients. Among 12 UC patients with positive serum infliximab, 3 (25.0%) patients, and 4 of 19 (21.1%) patients in CD developed SSIs. There was no significant difference in the incidence of SSI compared to patients with negative serum infliximab of both patients (UC; 1/9, 10%, p=0.36) (CD; 2/3, 66.7%, P=0.099). Mean pre-operative serum infliximab concentrations with SSIs were 5.78±3.51μg/dL in UC patients and 6.01±4.23μg/ dL in CD patients, there was no significant differences compared with non-SSI groups (UC; 7.46±7.90μg/dL, P=0.93) (CD; 4.04±0.99μg/dL, P=0.76). In addition, no significant association was found between post-operative serum infliximab concentration and with or without SSI in both patients (UC; 4.17±7.60 vs 7.60±7.18μg/dL, p=0.52) (CD; 4.38±3.92 vs 2.26±1.86μg/dL, p=0.32). CONCLUSIONS: Serum infliximab concentrationwas significantly decreased during surgery in patients with CD but UC. However, there was no influence of perioperative serum infliximab concentration on SSI in patients with inflammatory bowel diseases.

Meta‐analysis: peri‐operative anti‐TNFα treatment and post‐operative complications in patients with inflammatory bowel disease

The impact of peri-operative use of TNFα antagonists on post-operative complications such as infection and wound healing is controversial. To conduct a systematic review and meta-analysis to assess the impact of peri-operative use of TNFα antagonists on post-operative complications such as infection and wound healing in patients with inflammatory bowel disease (IBD). A literature search identified studies that investigated post-operative outcomes in patients with IBD using TNFα antagonists. The primary outcome was the rate of post-operative infectious complications. Secondary outcomes included the rates of non-infectious complications and total complications. Odds ratios (OR) with 95% confidence intervals (CI) are reported. Overall, 18 studies with 4659 participants were eligible for inclusion. Patients with IBD using preoperative anti-TNFα therapies had significant increases in post-operative infectious [OR 1.56 (95% CI, 1.09-2.24)], non-infectious [OR 1.57 (95% CI, 1.14-2.17)] and total complications [OR 1.73 (95% CI, 1.23-2.43)]. Studies limited to patients with Crohn's disease demonstrated a statistically significant increase in infectious (OR 1.93, 95% CI 1.28-2.89) and total (OR 2.19, 95% CI 1.69-2.84) complications, and a trend towards increase in non-infectious complications (OR 1.73, 95% CI 0.94-3.17). Studies of patients with ulcerative colitis did not demonstrate significant increases in infectious (OR 1.39, 95% CI 0.56-3.45), non-infectious (OR 1.40, 95% CI 0.68-2.85), or total complications (OR 1.10, 95% CI 0.81-1.47). Anti-TNFα therapies appear to increase the risk of post-operative complications. The increase in risk is small, and may well reflect residual confounding rather than a true biological effect. Nevertheless, physicians should exercise caution when continuing biological therapies during the peri-operative period.

PERIOPERATIVE ANTICOAGULATION AND THROMBOLYSIS IN CONGENITAL AND ACQUIRED COAGULOPATHIES

Patients with congenital or acquired coagulopathies are undergoing increasingly complex operations that may require anticoagulation. Using large doses of heparin in patients with hemophilia during coronary artery bypass surgery without first correcting the underlying coagulation deficit may have catastrophic consequences. Before 1965, mortality for hemophiliacs undergoing general surgical procedures ranged from 13% to 67%. Over the last 30 years, operations on patients with hemophilia and other coagulopathies have been performed with low morbidity and mortality results, primarily because of improved laboratory testing, perioperative administration of coagulation factors to bring the missing factor activity to normal, and close perioperative follow-up to evaluate and further correct hemostatic protein activity. 200 To prepare these patients properly for surgery, complex diagnostic tests and specific therapies are required preoperatively because diagnosis and treatment during the surgery may be difficult or impossible, with severe consequences for the patient. As the perioperative use of anticoagulants in patients with congenital coagulopathies is becoming safe and routine, physicians are becoming aware of other acquired coagulation disorders such as heparin-induced thrombocytopenia. Heparin-induced thrombocytopenia has special clinical significance because heparin is still the first-choice treatment for the systemic anticoagulation required for certain cardiac and vascular surgeries. Finding that it was contraindicated in some patients stimulated intense research for alternatives, which produced heparin substitutes such as heparinoids, low molecular weight heparins (LMWHs), direct thrombin inhibitors, and glycoprotein IIb/IIIa receptor inhibitors. The expansion of knowledge about the coagulation and anticoagulation mechanisms over the last several decades has also brought a better understanding of some of the thrombotic phenomena that anesthesiologists and surgeons encounter in their daily practice. The increased incidence of thrombosis in some segments of the population is now known not to be simple “bad luck,” but rather to be the result of underlying pathologies of the coagulation cascade, most commonly protein C, protein S, and antithrombin III deficiencies. In 1993, investigators in Sweden 38 and the Netherlands 111 described a new defect in the hemostatic pathway, called resistance to activated protein C. This disorder occurs in 4% to 6% of the US population, making them especially prone to thromboembolic events during the perioperative period, pregnancy, or oral contraceptive use. Antiphospholipid antibodies may also cause a hypercoagulable state. Taylor et al 194 demonstrated that antiphospholipid antibodies are present in 25.6% of patients undergoing peripheral vascular surgery. This patient population may require not only short-term perioperative thrombotic prophylaxis but also long-term prophylaxis. However, dosage and duration of anticoagulant therapy for some of the hypercoagulable states is still not fully defined. In this article, we describe the pathophysiology of the most common hyper- and hypocoagulable disorders and discuss the impact of perioperative use of anticoagulants and thrombolytics in patients with these conditions.