**11. Stroke**

There is considerable evidence that in spinal cord injury patients interruption of neurologic impulses and the ensuing paralysis cause profound metabolic changes in blood vessels accountable for venous thrombosis.

Vascular adaptations to inactivity and muscle atrophy, rather than the effect of a nonworking leg-muscle pump and sympathetic denervation, cause thrombosis, indicating that thrombosis established through venous incompetence cannot be reversed by anticoagulation alone.

Therefore, the estimated death rate from PE in patients who died with heart failure was 3% to 10%. CHF seems to be a stronger risk factor in women. Dries and colleagues97 reported a higher proportion of PE in women (24%) compared with men (14%). We too showed a higher relative risk of PE and of DVT in women with CHF than in men.102 Although these data seemcompelling, multivariate logistic analysis failed to identify CHF as an independent risk factor for DVT or PE.43 However, it was a risk factor for postmortem VTE that was not a cause of death.43 In one study of pediatric patients with dilated cardiomyopathy awaiting

Heart failure is the second most common risk factor for VTE in hospitalized patients, as

Hospitalized patients with exacerbations of COPD, when routinely evaluated, showed PE in 25% to 29%.108,109From 1979 to 2003, 58,392,000 adults older than 20 years were hospitalized with COPD in short-stay hospitals in the United States.110 PE was diagnosed in 381,000 (0.65%) and DVT in 632,000 (1.08%).110 The relative risk for PE in adults hospitalized with COPD was 1.92 and for DVT it was 1.30. Among those aged 20 to 39 years with COPD, the relative risk for PE was 5.34. Among patients with COPD aged 40 to 59 years, the relative risk for PE decreased to 2.02, and among patients aged 60 to 79 years the relative risk for PE was 1.23.110 The relative risk for DVT was also higher in patients with COPD aged 20 to 39 years (relative risk 5 2.58) than in patients aged 40 years or older (relative risk 0.92-1.17, depending on age).110 In young adults, other risk factors in combination with COPD are uncommon, so the contribution of COPD to the risk of PE becomes more apparent than in older patients. Although these data strongly suggest that COPD is a risk factor for PE and DVT, multivariate logistic analysis did not identify it as an independent risk factor.43 Others, with univariate

Neuhaus et al. 111 found pulmonary emboli in 27% of 66 autopsies performed in patients who had respiratory failure (not only as a decompensation of COPD) and died after

The largest study was conducted by Schonhofer and Kohler 112 on a population of 196 patients admitted to a respiratory intensive care unit. The authors found a DVT rate of 10.7% as assessed by US. The majority (86%) of cases were asymptomatic and, interestingly, almost all major clinical variables (such as age, weight, severity of dyspnea, lung function, situation of blood gases) failed to predict patients who were more likely to develop DVT.

There is considerable evidence that in spinal cord injury patients interruption of neurologic impulses and the ensuing paralysis cause profound metabolic changes in blood vessels

Vascular adaptations to inactivity and muscle atrophy, rather than the effect of a nonworking leg-muscle pump and sympathetic denervation, cause thrombosis, indicating that thrombosis established through venous incompetence cannot be reversed by

transplant the incidence of pulmonary embolism was 13.9% 106.

analysis, did not identify COPD as a risk factor.61

admission to a Respiratory Intensive Care Unit.

accountable for venous thrombosis.

anticoagulation alone.

shown in ENDORSE.107

**10. COPD** 

**11. Stroke** 

Spinal cord injuries with paralysis result in an immobile state with retardation of the blood flow caused by the relaxation of muscle and the atony of blood vessels. It is not surprising that spinal cord injuries are frequently complicated by the development of venous thrombosis, which is inevitably linked to hospitalization, immobilization, vein wall damage, stasis, and hypercoagulability. Deep vein thrombosis and pulmonary emboli remain the major complications in spinal cord injuries below the C2 through T12 vertebrae associated with motor complete or motor nonfunctional paralysis. 113,114,115,116,117,118,119 Two surprising findings set spinal cord injury apart from other risk factors for venous thrombosis: incidence of leg DVT and pulmonary embolism in spinal cord injury is three times higher than in the general population.

Patients with stroke are at particular risk of developing DVT and PE because of limb paralysis, prolonged bed rest, and increased prothrombotic activity.120 Among 14,109,000 patients with ischemic stroke hospitalized in short-stay hospitals from 1979 to 2003, VTE was diagnosed in 165,000 (1.17%).121 Among 1,606,000 patients with hemorrhagic stroke, the incidence of VTE was higher (1.93%).

Among patients with ischemic stroke who died from 1980 to 1998, PE was the listed cause of death in 11,101 of 2,000,963 (0.55%).122 Based on an assumed sensitivity of death certificates for fatal PE of 26.7% to 37.2%,105,123 the corrected rate of fatal PE was 1.5% to 2.1%. Death rates from PE among patients with ischemic stroke decreased from 1980 to 1998, suggesting effective use of antithrombotic prophylaxis.
