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Amir K Jaffer

Publications and source records attributed to Amir K Jaffer.

12 recordsLinked to original sources
PubMed2006

Prevention of venous thromboembolism in the geriatric patient.

Elderly patients immobilized because of an acute medical illness or surgery have a very high risk of developing venous thromboembolism (VTE). Aggressive pharmacologic prophylaxis is necessary and should be initiated either at admission for a medical condition or shortly after surgery. Aggressive prophylaxis may result in fewer patients developing VTE in the hospital and ultimately lead to fewer patients requiring full-dose anticoagulation for VTE. Mechanical prophylaxis can be used as an adjunct to an anticoagulant-based regimen but should only be used as primary prophylaxis when there is a contraindication, such as active bleeding. It is recommended that the clinician carefully evaluate the elderly patient's creatinine clearance and weight before prescribing anticoagulants, particularly when using fixed dosing regimens.

Age Factors↗
PubMed2005

Low-molecular-weight-heparins as periprocedural anticoagulation for patients on long-term warfarin therapy: a standardized bridging therapy protocol.

BACKGROUND: Over 2 million patients in North America are on warfarin anticoagulation therapy for prevention of thromboembolism. Suspension of warfarin therapy is often required to prepare patients for invasive procedures or surgeries. To protect these patients against thromboembolism while they are off warfarin, shorter-acting parenteral agents such as low-molecular-weight heparins (LMWHs) are often used. We conducted a retrospective observational study of our anticoagulation clinic patients to assess the safety and efficacy of LMWHs using a standardized protocol for periprocedural anticoagulation therapy. METHODS: We included 69 consecutive patients who required interruption of their long-term warfarin therapy between August 2001 and August 2002, and were deemed by the treating physician to be at high enough risk for perioperative thromboembolism to justify bridging anticoagulation. We used a standard bridging therapy protocol in our anticoagulation clinic. Sixty-six patients received enoxaparin and three patients received tinzaparin for a mean duration of 7.7 days postoperatively. Outcomes were assessed for 30 days post-procedure. Safety outcomes included major bleeding and minor bleeding. Efficacy outcomes included thromboembolic event or death. RESULTS: There were two major bleeding events, one minor bleeding event, and no cases of thromboembolism. Twelve patients experienced some bruising around the injection site. CONCLUSIONS: LMWH administration using our standard outpatient bridging protocol for perioperative anticoagulation appears to be relatively safe and efficacious, offering an alternative to inpatient administration of intravenous unfractionated heparin (UFH). Our study provides additional evidence to the limited published observational data regarding the safety and efficacy of LMWH as bridging therapy in the perioperative and periprocedural setting. Large, multicenter, randomized controlled trials are necessary to fully assess the safety and efficacy of LMWH for perioperative anticoagulation.We conducted a retrospective observational study of 69 consecutive anticoagulation clinic patients on warfarin between August 2001 and August 2002, who were undergoing a procedure or surgery. The study was done to assess the safety and efficacy of an outpatient LMWH bridging protocol. Sixty-six patients received enoxaparin and three patients received tinzaparin for a mean duration of 3 days preoperatively and 7.7 days postoperatively. Outcomes were assessed for 30 days post-procedure. Safety outcomes included major bleeding and minor bleeding. Efficacy outcomes included thromboembolic event or death. There were two major bleeding events, one minor bleeding event, and no cases of thromboembolism. Twelve patients experienced some bruising around the injection site.

Adult↗
PubMed2005

Duration of anesthesia and venous thromboembolism after hip and knee arthroplasty.

OBJECTIVE: To determine whether longer duration of anesthesia predisposes patients undergoing orthopedic surgery to venous thromboembolism (VTE). PATIENTS AND METHODS: We conducted a secondary analysis of a retrospective case-control study that examined risk factors for postoperative VTE in postmenopausal women. We matched women aged 50 years and older with radiographically confirmed postoperative VTE (cases) by age, surgeon, year of surgery, and surgical joint (knee vs hip) with women without postoperative VTE (controls). Duration of anesthesia, operative variables, demographic data, comorbid illnesses, and laboratory data were determined by medical record review. RESULTS: Eighty-eight cases were matched with 181 controls. Duration of anesthesia of 3.5 hours or longer (corresponding to the upper tertile of patients) was strongly associated with postoperative VTE compared with a shorter duration of anesthesia (odds ratio, 3.58; 95% confidence Interval, 2.11-6.16; P < .001). This relationship was maintained after controlling for multiple covariates with propensity score methods, Including type of arthroplasty, route of anesthesia, type of antithrombotic prophylaxis, and surgical approach. In multivariate analysis, the Important predictors of VTE included anesthesia duration of 3.5 hours or longer, type of antithrombotic prophylaxis, revision (vs primary) arthroplasty, and allogeneic blood transfusion. CONCLUSION: We found a marked association between the duration of anesthesia and postoperative VTE in patients undergoing Joint arthroplasty. Although it is possible that unmeasured intraoperative variables account for this relationship, we suggest that duration of anesthesia may be an important risk factor for postoperative VTE after orthopedic surgery.

Anesthesia↗
PubMed2005

Current and emerging options in the management of venous thromboembolism.

Venous thromboembolism (VTE) is a common disease whose diagnosis is challenging. The best diagnostic approaches combine the patient's pretest clinical probability of disease with D-dimer testing and/or diagnostic imaging. In light of several advantages, low-molecular-weight heparins are now recommended over unfractionated heparin for most patients with acute VTE. Newer anticoagulants such as the factor Xa inhibitor fondaparinux also show promise for acute VTE. For chronic management, the duration and intensity of warfarin therapy should be tailored to the individual patient.

Anticoagulants↗
PubMed2004

Postmenopausal hormone replacement and venous thromboembolism following hip and knee arthroplasty.

Hormone replacement therapy has been associated with venous thromboembolism. Controversy exists regarding the appropriate management of hormone replacement in the perioperative setting and in other situations--such as acute illness--predisposing to acute venous thromboembolism. We performed a case-control study to determine whether perioperative hormone replacement is associated with venous thromboembolism following hip and knee arthroplasty. 108 patients with postoperative venous thrombosis were matched by age, date and type of surgery, and surgeon with 210 controls without thrombosis. Perioperative hormone replacement use was no more prevalent in patients with postoperative thrombosis than those without. Eighteen (16.7%) women with post-operative thrombosis had taken perioperative hormone replacement compared to 49 (23.3%) of controls: odds ratio = 0.66; (95% CI 0.35-1.18; p=0.17). After multivariate analysis, the adjusted odds ratios were similar. Variables predicting post-operative thrombosis included: prior venous thromboembolism (OR = 2.3; p = 0.02), rheumatologic disease (OR = 2.2; p = 0.03), and absence of pharmacologic antithrombotic prophylaxis (OR = 13.4; p = 0.005). Cases and controls were otherwise similar. Users of hormone replacement were similar to non-users except that they were less likely to have coronary disease (OR 0.34; p = 0.03) or prior thrombosis (OR = 0.28; p = 0.04), and were younger (median age 67 versus 74 years; p <0.0001). We found no association between perioperative hormone replacement and post-operative thrombosis in patients undergoing major orthopaedic surgery. Routine discontinuation of these medications preoperatively--and possibly in other situations predisposing to thrombosis, such as acute medical illness--may be unnecessary in patients receiving appropriate pharmacologic antithrombotic prophylaxis.

Acute Disease↗
PubMed2004

Warfarin prophylaxis and venous thromboembolism in the first 5 days following hip and knee arthroplasty.

Many orthopaedic surgeons use warfarin to prevent venous thromboembolism (VTE) following hip or knee arthroplasty. Since warfarin's antithrombotic effects are delayed, we hypothesized that early VTE (occurring within 5 days post-operatively) would be more common in arthroplasty patients receiving warfarin monotherapy compared to those receiving enoxaparin. We performed a secondary analysis of a case-control study examining risk factors for post-operative thrombosis in postmenopausal women. We defined cases as patients who were diagnosed with thrombosis within 5 days of surgery. Controls without thrombosis were matched with cases by age, surgeon, year of surgery and surgical joint. 84 women with early post-operative thrombosis (cases) were matched with 206 controls. 18 cases (21.4%) had been prescribed warfarin mono-therapy, compared with 7 controls (3.4%). 58 (69.1%) cases and 195 (94.7%) controls had been prescribed subcutaneous enoxaparin 30 mg twice daily, starting 12-24 hours after surgery. The odds ratio for any early thrombosis in patients receiving warfarin as opposed to enoxaparin 30 mg twice daily was 8.6 (p<0.0001). For proximal thrombosis, the odds ratio was 11.3 (p<0.0001). Multivariate analysis did not alter these findings. Warfarin's delayed antithrombotic effects may not provide adequate VTE prophylaxis in the immediate post-operative setting. We suggest caution in employing warfarin monotherapy following joint arthroplasty.

Aged↗
PubMed2003

When patients on warfarin need surgery.

When a patient who has been taking warfarin long-term needs to undergo surgery, how to manage his or her anticoagulation is controversial. We believe most patients should stop taking warfarin 5 days before elective surgery, and most do not need to receive heparin in the perioperative period as a bridge to surgery.

Anticoagulants↗