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Back To Vidyya Pulmonary artery false aneurysm formation due to PA-catheters


Recommendations Out Of The Literature


 

Pulmonary artery (PA) false aneurysm (PAFA) formation, induced by a Swan-Ganz catheter is a well known complication. It is estimated to occur in 0.06 to 0.2% of cases with a PA-catheter and is associated with a mortality rate of 45 to 65%.[1, 2]

Risk factors

Established risk factors include female patients, an age greater than 60 years, the presence of pulmonary hypertension [3], anticoagulation, stiff catheters (hypothermic cardiopulmonary bypass) [4], repeated manipulations during cardiopulmonary bypass (CPB) with migration of the PA-catheters distally as well as leaving the catheter in its original position during CPB. [5, 1, 6]

Mechanism and pathogenesis

There are various mechanisms possible:

direct rupture of the vessel by the inflated balloon or by the catheter tip itself, e.g. by eccentric inflation of the balloon. It is noteworthy to remember, that the pressure in a correct inflated balloon is about 300 mmHg. This pressure is exceeded two- to three-times while inflating such a balloon. [1]

The pathogenetic mechanism in the development of the formation of a PAFA includes the laceration of the vessel wall with direct bleeding into the pulmonary parenchyma. When this bleeding extends into the airways, hemoptysis will result. A rupture through the visceral pleura on the other hand can lead to a hemothorax. Very small lacerations sometimes reendothelialize. PAFA's do not have any intact vessel layer. The aneurysmal sac is formed only by compressed lung parenchyma. [7]

This leaves these aneurysms prone to rupture since they are inherently unstable. [8]

Clinical Signs

The signs are related to the pathogenesis: new pulmonary infiltrates in the region of the tip of the PA-catheter, hemoptysis, hemothorax or pericardial tamponade (rare) [5].

Diagnosis

Due to its high mortality the diagnosis of an PAFA after an initial bleeding is essential. Radiologic findings are well-defined, persistent, pulmonary nodules or masses adjacent to the catheter tip.

The method of choice in diagnosing PAFA's has been said to be contrast enhanced CT-scans, especially in patients with pulmonary hypertension. Pulmonary angiography is the second diagnostic tool. [1, 8]

Management

The goals of any therapeutic approach are as follows:

  • Decrease bleeding
  • Correct hypovolemia
  • Preserve the function of the unaffected lung
  • Preserve gas-exhange
  • Localize the source of the bleeding

To achieve this goal, the following recommendations have been made:

Position the patient with the affected lung dependent to prevent soiling of the contralateral lung. After separation of both lungs (either with a bronchial blocker or with a double-lumen tube) the affected lung should be positioned uppermost to reduce the pulmonary artery pressure.

Hemostasis should be controlled by reversal of the heparin (if used e.g. for CPB), replacement of platelets and administration of coagulation factors (fresh-frozen-plasma).

As soon as the patient is stable enough, diagnosis should be made and embolisation of the branch of the pulmonary artery should be attempted, using stainless steel wire coils. [9, 10, 11]

Surgical therapeutic options include direct repair of the vessel (seldom) or resection of the affected lung segment.

In cases with severe bleeding an aggressive surgical approach is mandatory: chest tubes should be placed in large hemothorax (autotransfusion should be considered) and temporary ligation of one PA could be necessary.

Pulmonary bleeding after restoration of spontaneous circulation after CPB should be an early warning sign. Resuming CPB and exploration of the surgical field may be necessary. [5, 11, 2]

Prevention

To prevent every case of PA-catheter related PAFA probabely is not possible. Special attention should be paid to the described risk-factors. PA-catheters should be without any technical failure and the balloon at the tip should inflate symetrically. Withdrawal of the PA-catheter a few centimeters before CPB is mandatory.

 

References

1. De Lima LG, Wynands JE, Bourke ME, Walley VM: Catheter-induced pulmonary artery false aneurysm and rupture: case report and review. J Cardiothorac Vasc Anesth 8:70-75, 1994

2. Robin ED: Death by pulmonary artery flow-directed catheter. time for a moratorium? Chest 92:727-731, 1987

3. Feng WC, Singh AK, Drew T, Donat W: Swan-ganz catheter-induced massive hemoptysis and pulmonary artery false aneurysm. Ann Thorac Surg 50:644-646, 1990

4. Cohen JA, Blackshear RH, Gravenstein N, Woeste J: Increased pulmonary artery perforating potential of pulmonary artery catheters during hypothermia. J Cardiothorac Vasc Anesth 5:234-236, 1991

5. Cicenia J, Shapira N, Jones M: Massive hemoptysis after coronary artery bypass grafting. Chest 109:267-270, 1996

6. Thrush DN, Jeffries D: Pulmonary hemorrhage during cardiac surgery. J Cardiothorac Vasc Anesth 5:377-378, 1991

7. Fraser RS: Catheter-induced pulmonary artery perforation: pathologic and pathogenic features. Hum Pathol 18:1246-1251, 1987

8. Smart FW, Husserl FE: Complications of flow-directed balloon-tipped catheters. Chest 97:227-228, 1990

9. Carlson TA, Goldenberg IF, Murray PD, Tadavarthy SM, Walker M, Gobel FL: Catheter-induced delayed recurrent pulmonary artery hemorrhage. intervention with therapeutic embolism of the pulmonary artery. JAMA 261:1943-1945, 1989

10. Davis SD, Neithamer CD, Schreiber TS, Sos TA: False pulmonary artery aneurysm induced by swan-ganz catheter: diagnosis and embolotherapy. Radiology 164:741-742, 1987

11. Kirton OC, Varon AJ, Henry RP, Civetta JM: Flow-directed, pulmonary artery catheter-induced pseudoaneurysm: urgent diagnosis and endovascular obliteration. Crit Care Med 20:1178-1180, 1992

12. Roberts LC, Ramsay MA, Alivizatos PA, Walling PT, Lee SP: Successfully treated pulmonary artery rupture complicated by aneurysm formation. J Cardiothorac Vasc Anesth 6:70-72, 1992

 

 



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