Update on Anticoagulant Medications for the Interventional Radiologist

Anticoagulation and Antiplatelet Agents in Peripheral Arterial Interventions

Effective revascularization of peripheral artery disease relies on periprocedural pharmacological regulation of the clotting cascade. Patient-specific factors such as cardiovascular risk factors, contraindications, and individual psychosocial factors must be considered when initiating post revascularization management. Management with anticoagulant and antiplatelet agents is discussed to guide the interventionalist on which therapy may be appropriate for their patient. While exact treatment may be institution and provider dependent, the interventionist must be familiar with the available classes of medications and how they can be prescribed in the postprocedural setting to improve cardiovascular outcomes.

Treatment of a heart base tumor and chylothorax with endovascular stent, stereotactic body radiation therapy, and a tyrosine kinase inhibitor in a dog

An 8-year-old 28-kg male castrated rough collie was evaluated for persistent chylothorax secondary to right atrial mass. Cardiac ultrasound and computed tomography revealed a right atrial intra- and extraluminal mass with partial obstruction of the cranial vena cava and secondary chylothorax. Vascular stent placement was elected to alleviate cranial vena cava obstruction and secondary chylothorax. An 18 mm × 180 mm self-expanding stent was deployed in the region of the stricture, spanning the cranial vena cava and right atrium. An intrathoracic drainage catheter and subcutaneous port were placed within the right hemithorax, and antiplatelet therapy was initiated. Four weeks later, the dog underwent stereotactic body radiation therapy. Three months following treatment, the dog was diagnosed with supraventricular tachycardia and received antiarrhythmic therapy and antiangiogenic/antiproliferative medication (Palladia™). Subsequent evaluations confirmed the resolution of arrhythmia and pleural effusion. Combined vascular stent placement and stereotactic body radiation therapy for the treatment of a right atrial intraluminal and extraluminal mass leading to cranial vena cava compression and subsequent chylothorax may lead to long-term survival. A good outcome was achieved in this patient due to resolution of pleural effusion, as well as cytoreduction and presumably delayed progression of tumor growth.

Complication rate of ultrasound-guided percutaneous cholecystostomy in patients with coagulopathy

OBJECTIVE

The purpose of this article is to compare the complication rate for ultrasound-guided percutaneous cholecystostomy in patients with coagulopathy to the rate in patients with normal coagulation.

MATERIALS AND METHODS

We performed a database search for patients who underwent ultrasound-guided percutaneous cholecystostomy from January 2000 through December 2010. Patients were divided into those with normal coagulation and those with coagulopathy, as documented by abnormal laboratory values (international normalized ratio ≥ 1.5 and platelet count ≤ 50 × 10(9)/L) or history of anticoagulant medication in the preceding 5 days. Medical records were reviewed, and complication rates and subsequent treatment was recorded. Statistical analysis was performed using the Fisher exact and chi-square tests.

RESULTS

Two hundred forty-two patients underwent ultrasound-guided percutaneous cholecystostomy (132 men and 110 women; mean [± SD] age, 73.9 ± 15.9 years; range, 22-104 years). One hundred thirty-two patients were coagulopathic and 110 had normal coagulation. Major complications related to ultrasound-guided percutaneous cholecystostomy were rare (4/242 cases [1.7%]) and included hemorrhage requiring transfusion (n = 1), death directly related to the procedure (n = 1), sepsis related to the procedure (n = 1), and abscess or biloma formation (n = 1). All of these occurred in the group with normal coagulation. Fourteen additional deaths (5.8%) that occurred within 30 days of the procedure were related to comorbidities. Minor catheter-related complications (15/242 [6.2%]) were due to catheter dislodgement (n = 11 [4.5%]), failure of placement (n = 1 [0.4%]), and hemorrhage not requiring transfusion (n = 3 [1.2%]). Two of the minor hemorrhagic complications were seen in the coagulopathic group and one in the normal coagulation group (p = 0.599).

CONCLUSION

There is no difference in the complication rate for ultrasound-guided percutaneous cholecystostomy in patients who are coagulopathic compared with those who have normal coagulation.

Coagulation concepts update

OBJECTIVE

Since the previous comprehensive radiology review on coagulation concepts that was done in 1990, many studies have been published in the medical and surgical literature that can guide the approach of a radiology practice. The purpose of this article is to provide an analysis of these works, updating the radiologist on proper use and interpretation of coagulation assessment tools, medications that modify the hemostatic system, and the use of transfusions prior to interventions.

CONCLUSION

The basic tools for coagulation assessment have not changed; however, results from subspecialty research have suggested ways in which the use of these tools can be modified and streamlined to safely reduce time and expense for the patient and the health care system.

New classes of anticoagulation and antiplatelet agents: preprocedure management and safety guidelines for imaging-guided intervention

OBJECTIVE

New medications are available for prophylaxis of deep venous thrombosis, the treatment of venous thromboembolism, and also to reduce the risk of acute coronary syndrome and stroke. The purpose of this review is to provide the radiologist a practical and succinct summary of the new anticoagulation and antiplatelet medications and how to manage these medications in patients who are in need of a radiology intervention.

CONCLUSION

This article provides recommendations for preprocedure management of new anticoagulants and antiplatelet agents in patients undergoing radiology intervention.

Time to Hemostasis after Traction Removal of Tunneled Cuffed Central Venous Catheters

PURPOSE

Many patients undergo placement of tunneled cuffed central venous catheters (TCCVCs) for indications including administration of medical therapy and hemodialysis. They are removed when no longer needed or if there is a device complication. There is no consensus regarding the necessity of routine preremoval coagulation studies or platelet count, so this study was performed to determine if abnormal coagulation status affects the time to hemostasis (TH) after traction removal of TCCVCs.

MATERIALS AND METHODS

Adult patients referred to our group for removal of a TCCVC placed via a jugular or subclavian route were considered candidates for inclusion. Blood was submitted for evaluation of prothrombin time (PT) and International Normalized Ratio (INR), activated partial thromboplastin time (aPTT), and platelet count. Catheters were removed with the traction technique, and presence of hemostasis was assessed at 5-minute intervals of manual compression.

RESULTS

Between November 19, 2001, and April 20, 2004, 179 subjects were enrolled and completed the study. There were 165 subjects in whom TH was within the first 5-minute interval and 14 in whom more than 5 minutes was required. Statistically significant factors associated with prolonged TH were primary diagnosis of end-stage renal disease (P = .005), use of antiplatelet agents (P = .03), and procedure performed by a "low-volume" operator (P = .002).

CONCLUSIONS

Routine preremoval evaluation of coagulation parameters is not necessary. Patients who are likely to have abnormal platelet function but not abnormal platelet number appear to be at risk for prolonged TH, but even in those cases, the THs are rarely more than 15 minutes.

Catheter-directed thrombolysis for acute limb ischemia

Acute limb ischemia is a potentially life-threatening clinical event. Thrombosis in situ, bypass graft thrombosis, and embolic occlusion are the three major precipitating events leading to acute limb ischemia. Management of acute ischemia depends on the clinical status of the affected limb and patient comorbidities. Catheter-directed thrombolysis (CDT) is the treatment of choice for patients with relatively mild acute limb ischemia (Rutherford categories I and IIa) with no contraindications to thrombolytic therapy. Patients with severe acute limb ischemia (Rutherford category IIb) need emergent revascularization. CDT should be considered, nonetheless, if the relative risks compared with primary operation are favorable. CDT is a life- and limb-saving treatment for many patients despite limitations of efficacy and associated complications. This article is a review of the etiology of acute arterial occlusion; clinical triage of patients presenting with acute limb ischemia; catheter guide wire techniques, pharmacological agents, and devices in current use for CDT; as well as the outcomes of CDT.