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Preventing venous thromboembolism in long-term care residents: Cautious advice based on limited data

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WHICH LONG-TERM CARE RESIDENTS SHOULD RECEIVE VTE PROPHYLAXIS?

No validated risk-assessment model is available to help clinicians decide whether to give thromboprophylaxis in medical patients, whether they are in a medical ward with an acute illness or in a long-term care facility with a chronic illness. However, general risk factors for VTE are known (Table 2). In general, it is reasonable to assess all new residents of a long-term care facility for these risk factors and to reassess them if their health status changes.

Old age and immobility are not the only risk factors

The current ACCP guidelines suggest considering thromboprophylaxis for hospitalized medical patients over age 75 who cannot walk without assistance.13 However, we lack evidence to suggest a similar strategy in long-term care residents.

The ACCP guidelines are based on data on risk. Nearly 25% of elderly patients with confirmed pulmonary embolism had been immobile prior to their diagnosis.8 In addition, prolonged bed rest (> 14 days) has been reported to be the strongest independent risk factor for symptomatic deep venous thrombosis, increasing the risk more than fivefold.20 Advanced age is also considered a risk factor for VTE, as risk starts to increase at age 40 and doubles each decade of life thereafter.18

No study has assessed the impact of these factors on the risk of VTE in long-term care residents. Since most of such patients are elderly and have impaired mobility, we believe a more selective approach should be used in assigning VTE risk status, one that does not use advanced age and immobility as the only criteria for starting thromboprophylaxis.

Residents of long-term care facilities may be immobile because of underlying illness or disability, such as cognitive impairment, sensory impairment (eg, poor access to corrective lenses and hearing aids), or poor access to assist devices (eg, walkers, canes). In addition, iatrogenic factors that decrease mobility such as indwelling bladder catheters and physical restraints are also common in such patients.

Efforts to improve mobility should be encouraged. However, we recommend that thromboprophylaxis be considered only in patients who have both impaired mobility and an intercurrent acute medical illness such as an acute infection or acute inflammatory disease.13

A related issue is the difference between long-term care residents with a chronic but stable disease and those with acute disease. Patients with acute exacerbations of congestive heart failure or chronic obstructive lung disease may be considered for thromboprophylaxis, as they become more comparable to acutely ill medical patients in whom clinical trials have shown the effectiveness of anticoagulant prophylaxis. On the other hand, patients with these diseases who remain stable may not need prophylaxis.

This approach avoids giving long-term anticoagulant prophylaxis to patients who have irreversible diseases and limits the use of these drugs and devices to higher-risk periods.

Consider thromboprophylaxis if…

Figure 1.

In view of these considerations, we believe it is reasonable to consider anticoagulant prophylaxis for long-term care residents if they have (Figure 1)9:
  • An acute exacerbation of congestive heart failure or chronic obstructive pulmonary disease
  • Acute infection (eg, urosepsis, pneumonia, cellulitis, infectious diarrhea)
  • An acute exacerbation of an inflammatory disease (eg, rheumatoid arthritis)
  • Active cancer (eg, patient receiving radiation therapy or chemotherapy)
  • Immobility and prior VTE.

Do not routinely consider prophylaxis if…

We also believe patients should not be routinely considered for anticoagulant VTE prophylaxis if they have:

  • Chronic but stable cardiorespiratory disease
  • Chronic but stable infectious or inflammatory disease
  • Terminal cancer with very limited life expectancy
  • Any contraindication to anticoagulants (eg, active bleeding, recent bleeding, coagulopathy, thrombocytopenia).

ANTICOAGULANT PROPHYLAXIS POSES RISKS IN LONG-TERM CARE RESIDENTS

Bleeding is the principal risk

Bleeding can occur at a heparin injection site or at remote sites, most often in the gastrointestinal tract. Bleeding at remote sites is generally associated with a precipitating factor such as an occult peptic ulcer leading to gastrointestinal bleeding or amyloid angiopathy leading to intracranial hemorrhage. Risk factors for bleeding are listed in Table 3.

The incidence of clinically important bleeding associated with anticoagulant prophylaxis is 0.2% to 5.6%, and the risk of fatal bleeding is 0.02% to 0.5%.21–24

As no randomized trial has examined anticoagulant prophylaxis in elderly long-term care residents, their bleeding risk with this therapy is unclear. However, older patients are likely to be at higher risk than younger patients because they have more comorbidities, take more drugs that could interact with heparin and potentiate bleeding, and have fragile skin, predisposing to injury from subcutaneous injections.

Also, renal function tends to decline with age. In a retrospective study of 854 outpatients over age 65, 29% had moderate renal insufficiency (creatinine clearance 30–50 mL/min), and 6% had severe renal insufficiency (creatinine clearance < 30 mL/min).25 Recent evidence suggests that some low-molecular-weight heparins (dalteparin and tinzaparin) do not bioaccumulate in patients with impaired renal function. However, enoxaparin and fondaparinux should be used with caution in patients with moderate to severe renal impairment.

Though much attention has recently been paid to increasing anticoagulant doses if the patient is obese, residents of long-term care facilities are more likely to be underweight. Dose adjustment should be considered when a low-molecular-weight heparin or fondaparinux is given to patients weighing less than 50 kg.

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