What is the recommended treatment for a clotted Hemodialysis (HD) catheter using alteplase (tissue plasminogen activator)?

Treatment of Clotted Hemodialysis Catheter with Alteplase

Instill 2 mg alteplase in 2 mL into each occluded catheter lumen with an initial 30-minute dwell time, extending to 120 minutes if unsuccessful, and administer a second identical dose if patency is not restored. 1, 2

Initial Bedside Management

Before using alteplase, attempt these maneuvers first:

• Reposition the patient to Trendelenburg position 1
• Perform forceful saline irrigation to dislodge possible thrombus 1, 2
• Reverse the arterial and venous lumens temporarily to complete the dialysis session 1
• Rule out mechanical malposition or kinking 2

Alteplase Dosing Protocol

Standard Adult Dosing

• Administer 2 mg alteplase in 2 mL per occluded lumen 1, 2
• The 2 mg dose is superior to 1 mg for restoring catheter function, with significantly longer catheter survival (955 days vs 782 days, HR 2.75 for removal with 1 mg dose) 1
• For patients <30 kg, use 110% of internal lumen volume, not exceeding 2 mg in 2 mL 2

Dwell Time Strategy

• Initial dwell time: 30 minutes, then assess for restoration of function 2
• If unsuccessful, extend dwell time to 120 minutes before reassessing 2
• Alternative protocols using 40-50 minute dwell times have shown comparable efficacy 3, 4

Repeat Dosing

• Administer a second identical 2 mg dose if patency is not restored after maximum dwell time 1, 2
• Success rates: 75% after one dose, 85-88% after two doses 2
• Up to 95% success with alteplase versus 82% with urokinase after initial dose 3

Expected Efficacy by Clinical Context

The timing of occlusion significantly impacts success rates:

• Occlusions <14 days old: 68% success after one dose, 88% after two doses 2
• Occlusions >14 days old: 57% success after one dose, 72% after two doses 2
• Overall clearance: 52% of catheters within 30 minutes, 86% after two doses 1

Safety Profile

Alteplase for catheter clearance demonstrates excellent safety:

• Zero incidence of intracranial hemorrhage in large trials 2
• No major bleeding or thromboembolic events in pediatric studies of 310 children 1
• No serious adverse events attributed to alteplase in multiple RCTs 1, 3, 4
• Minimal systemic absorption with intraluminal administration 1

Alternative Thrombolytic Agents

While alteplase is first-line, alternatives exist:

• Urokinase 5,000 IU/mL is equivalent to alteplase per KDOQI guidelines 1, 2
• Urokinase plus citrate 4% is also recommended as equivalent 2
• However, the American College of Chest Physicians designates tPA as the agent of choice due to FDA warnings regarding urokinase, superior in vitro clot lysis, fibrin specificity, and low immunogenicity 1, 2, 5
• Tenecteplase 2 mg showed 22% success versus 5% placebo in achieving blood flow ≥300 mL/min 1
• Reteplase 0.4 units achieved 88% success with potentially shorter dwell times 1, 6

When Alteplase Fails

If two doses of alteplase with maximum dwell time fail to restore patency:

• Consider mechanical interventions including guidewire insertion to dislodge tip thrombus 1
• Fibrin sheath stripping may be necessary 1
• Endoluminal brushing achieved 86% patency versus 50% with standard care 1
• Radiological evaluation and possible catheter exchange may be required 4, 7

Prevention of Recurrent Occlusion

After successful thrombolysis:

• Consider prophylactic weekly TPA locking solution to reduce future dysfunction 2
• Low-concentration citrate (<5%) locking solutions may prevent both infection and thrombotic dysfunction 2
• Risk factors for recurrence include diabetes (OR 1.56), exit site infection (OR 1.57), and longer catheter duration (OR 1.02 per day) 4

Critical Pitfalls to Avoid

• Do not skip bedside maneuvers before using alteplase—forceful saline irrigation alone may resolve many occlusions 1, 2
• Do not use 1 mg doses when 2 mg is available—the lower dose has 2.75 times higher risk of catheter removal 1
• Do not give up after 30 minutes—extending dwell time to 120 minutes significantly improves success 2
• Do not forget the second dose—success increases from 75% to 85-88% with repeat administration 2
• Do not use alteplase for non-thrombotic occlusions (lipid, mineral, or drug precipitates require different treatments) 1