Trauma and oral anticoagulants

Preinjury Warfarin and Geriatric Orthopedic Trauma Patients: A Case-Matched Study

BACKGROUND

This study examined the hypothesis that patients on warfarin before sustaining orthopedic injuries will have increased morbidity and mortality compared with matched control patients not on warfarin.

METHODS

Records of consecutive trauma patients on warfarin with orthopedic fractures who presented from January 1997 to June 2002 to a Level I trauma center were retrospectively analyzed. Data were evaluated using the chi and Student's t tests and nonparametric tests when appropriate; values of p < 0.05 were considered significant.

RESULTS

A study group of 53 patients was available for review. In comparison with the control group, significant differences were found in time delay from admission to surgery (p = 0.005), hospital length of stay (p = 0.03), total units of blood transfused (p = 0.03), and discharge disposition (p < 0.0003). No difference was found in number of intensive care unit days, complications, or mortality.

CONCLUSION

Preinjury warfarin impacts outcomes of geriatric trauma patients sustaining orthopedic injuries.

Outcomes of anticoagulated trauma patients

Patients on warfarin are at high risk for potentially life-threatening hemorrhage even after relatively minor trauma. Outcomes of these patients and the potential complications of reversing the effects of anticoagulation have received little attention. This study was performed to determine the overall outcome of orally anticoagulated patients who sustained injury as well as to determine any untoward effects of reversing their anticoagulated states. A retrospective study of injured patients on warfarin was conducted on patients admitted to an urban, university, tertiary-referral, level I trauma center between 1/1/93 and 12/31/96. Surviving patients were followed for a period of at least 1 month. Injuries were grouped by anatomic site. Charts were reviewed for degree of anticoagulation on admission (ie, initial international normalized ratio [INR]), survival, adverse effects of reversal of anticoagulation, and reinstitution of warfarin therapy. Discharged patients were contacted at home for follow-up. Thirty-five consecutive patients, 18 men and 17 women, on warfarin therapy at the time of their injuries were reviewed. The mean age was 75 years, with a range of 39 to 96. The mean follow-up period was 12.7 months. Reasons for anticoagulation included atrial fibrillation, prosthetic heart valves, revascularized limb, hypercoagulable state, deep venous thrombosis, pulmonary embolism, phlebitis, and aortic stenosis. Mean admission INR was 3.2, with a range of 1.6 to 10.0. There were 8 in-hospital deaths. Intracranial hemorrhages accounted for the majority of injuries. Ten patients were not given reversal therapy. Four complications were attributable to reversal therapy (upper extremity hemiplegia, transient ischemic attack, deep venous thrombosis, arterial thrombosis). Twenty-one patients had their warfarin reinstituted. Follow-up of surviving patients ranged from 1.5 to 42 months. Patients on warfarin are at high risk for intracranial hemorrhage following trauma. Patients on warfarin may be reversed during the acute period following injury, but transient complications may arise. Further prospective studies need to be conducted to determine which anticoagulated trauma patients may not require reversal therapy.

Intravenous vitamin K1 prior to orthotopic heart transplantation: effects in vivo and in vitro

BACKGROUND

Vitamin K1 is used to reverse warfarin's anticoagulant action. It is unclear whether intravenous vitamin K1 is safe or efficacious prior to urgent cardiac surgery.

METHODS

We retrospectively and prospectively examined the effects of preoperative intravenous vitamin K1 in vivo (administered for warfarin reversal immediately before heart transplantation) on intraoperative blood product utilization, hemodynamics and coagulation parameters. We also determined the direct effects of vitamin K1 in vitro on rings of human saphenous vein and internal mammary artery.

RESULTS

In the retrospective limb, 29 of 67 patients were administered vitamin K1 preoperatively via slow intravenous infusion. Vitamin K1 administration produced no adverse outcome but did not affect subsequent perioperative use of blood products. In the prospective limb (n = 10), vitamin K1 significantly (P < or = 0.01, Student t-test) altered mean arterial pressure (from 85 +/- 15 to 76 +/- 16 mmHg), systemic vascular resistance (from 1364 +/- 308 to 1078 +/- 252 dyn.s.cm-5), and cardiac index (from 2.3 +/- 0.3 to 2.7 +/- 0.3 L/min/m2) (mean +/- SD). Significant decreases in prothrombin time (19.8 +/- 2.7 to 17.7 +/- 1.8 s) and activated clotting time (164 +/- 26 to 137 +/- 24 s) were observed at 60 min. In vitro vitamin K1 (10(-7) to 10(-4) M) had no effect on the tone of noradrenaline-constricted rings.

CONCLUSIONS

Vitamin K1, administered by intravenous infusion prior to heart transplantation, did not alter subsequent perioperative blood product administration. Vitamin K1 rapidly reversed the anticoagulant effect of warfarin and produced modest hemodynamic changes. The decrease in systemic vascular resistance is probably not due to a direct effect of vitamin K1 on vascular smooth muscle.

Lateral cervical spine dislocation and vertebral artery injury

Although anterior and posterior traumatic displacement of cervical vertebrae are commonly noted, and the devastating neurological deficits associated with these injuries have been amply defined, lateral displacement with fractures has been rarely recognized, and the clinical significance of this injury has been overlooked. This report describes five cases of cervical spine fractures with lateral dislocation. All patients had lateral and anteroposterior cervical spine radiographs as well as cervical angiography or postmortem study demonstrating either complete occlusion or significant impairment of flow of the vertebral arteries. Two cases had traumatic vertebral artery occlusion with secondary medullary and cerebellar infarction resulting in the patient's death. Vertebral artery injury apparently is not uncommon in this particular type of fracture. The diagnosis of these vascular injuries may require angiography or magnetic resonance angiography. A vertebral occlusion or dissection is a problem of considerable complexity, requiring individualized management depending on the patient's symptomatology, location and nature of the injury, and time lapsed since the injury.