21 de setiembre del 2014
Marcello Di Valentino, MD1; Mario Alerci, MD2; Paolo Tutta, MD1; Fabio Sartori, MD1; Claudio Marone, MD1; Riccardo Vandoni, MD1; Felix Mahler, MD3; and Augusto Gallino, MD1
1Division of Vascular Medicine, Ospedale San Giovanni, Bellinzona, Switzerland
22Department of Radiology, Ospedale San Giovanni, Bellinzona, Switzerland
3Division of Angiology, Cardiovascular Department, Inselspital, University of Bern, Switzerland
While complete occlusion of the renal artery during passage of a guidewire is not uncommon, acute occlusion with complete flow impairment is a rarely reported phenomenon after successful dilation or stenting of a renal artery stenosis.1 The value of catheter thrombus aspiration for quick restoration of flow should be noted.
A 72-year-old man with severe arterial hypertension, impaired renal function (serum creatinine 150 μmol/L), and a history of peripheral artery disease was referred for elective percutaneous transluminal renal angioplasty and/or stenting of a proximal stenosis of the right renal artery. Diagnosis was established by magnetic resonance angiography. A renal resistance index of 0.68 was measured on duplex ultrasound. The patient was on aspirin therapy (100 mg/d). Preprocedural intra-arterial angiography confirmed the presence of a subtotal eccentric stenosis of the proximal right renal artery, with normal appearing distal vessels (Figure, A).
For the intervention, a 7-F guiding catheter (RDC 1; Cordis Endovascular, Miami, FL, USA) was introduced through a 7-F sheath. A 5000-unit heparin bolus was given intra-arterially. The lesion, which was crossed with a 0.018-inch guidewire (Tip Top; Stenlom, Denmark), was predilated with a 2.5×20-mm balloon catheter (Submarine Plus; Invatec, Brescia, Italy). Immediately, the target site became occluded, and no flow was observed in the renal artery and distal runoff (Figure, B). Flow could not be established either with further dilation (4×20-mm Submarine Plus balloon; Invatec) or with implantation of a 5×15-mm Genesis stent (Cordis Endovascular). Control angiography showed the stented segment open, but a large thrombus was seen in the distal main renal artery, which impaired flow to the branching vessels (Figure, C). The 7-F guiding catheter was advanced deep inside the ostium of the renal artery into close contact with the thrombus. At this time, an angiogram showed that the obstruction had moved distally (Figure, D). Urokinase (300,000 IU) was given through the guiding catheter for 10 minutes. A new angiogram did not reveal any sign of thrombolysis (Figure, E), so thrombus aspiration was indicated. Aspiration was performed via the guiding catheter; a 50-mL syringe with a Luer lock was connected to the guiding catheter by means of a Tuohy-Borst Y-adaptor, maintaining the guidewire inside the catheter and the renal artery. As soon as the vacuum was initiated by the syringe, the catheter occluded. With caution and under continuous aspiration, the guiding catheter was withdrawn while holding the guidewire inside the artery. The catheter was removed from the sheath and flushed with saline, which expelled a 2×5-mm thrombus. There was no material trapped inside the introducer sheath.
Control angiograms showed complete recanalization of the stented segment and the distal renal artery. The parenchyma was well contrasted apart from a small area at the lower pole (Figure, F). After successful recanalization, abciximab (Reo-Pro; Lilly, Leiden, The Netherlands) was given intravenously (0.25-mg/kg bolus over 1 minute followed by continuous infusion of 0.125 μg/kg/min for 12 hours). The patient remained free of symptoms during the entire procedure. There was no increase in the serum creatinine level or lactate dehydrogenase within 48 hours after the procedure. Serum creatinine 4 days after the procedure measured 110 μmol/L. Duplex ultrasound scans at discharge and 8 months after the intervention showed normal peak systolic velocities, renal aortic ratios, and resistance index (0.71).
Catheter intervention is a well-known and accepted treatment for renal artery stenoses.2 However, acute renal artery occlusion has been reported in 2% to 3% of the procedures.2,3 This complication is usually managed by percutaneous techniques rather than by surgery.3–5 Intra-arterial thrombolysis may play a role in the recanalization of the vessel,3,6 but it sometimes requires several hours with continuous monitoring in the interventional suite or intensive care unit. Alternative procedures include pulse-spray or repetitive thrombolytic bolus procedures, which may fail to dissolve thrombi that are not in close contact with the catheter (i.e., in side branches).3,6 Percutaneous thrombectomy can be performed either by thrombus aspiration or by mechanical thrombectomy involving thrombus expulsion or maceration/fragmentation and removal of the clot.7
Catheter thrombus aspiration is often used for occlusions of infrainguinal vessels8 and, more rarely, in the upper extremity or visceral arteries.4,7 Catheter aspiration requires a thin walled aspiration catheter with a large lumen (i.e., Cordis' Brite tip), a vascular sheath with removable hemostatic valve (i.e., Cordis' Avanti), and a 50 to 60-mL syringe with a Luer-lock connector. Aspiration catheters are available in sizes from 6 to 10 F with straight or curved tips. Local thrombolysis may help catheter aspiration by reducing the volume of the occluding material, facilitating fragmentation, and loosening the material for aspiration through the catheter.9 Catheter aspiration has some limitations, however. Larger amounts of thrombus may be aspirated only partially into the catheter and may get stuck in the introducer sheath. Hence, it is advisable to use a sheath with a removable hemostatic valve. Usually, it is possible to suck out the thrombus from the sheath by direct aspiration over several minutes with the valve removed. If not, the sheath is exchanged for a larger one.9
Serious complications are uncommon. Antegrade dissection can be avoided by advancing the catheter over the wire. If thrombolysis is used in conjunction with aspiration, the risk of bleeding may be increased after the introducer sheath is removed. Finally, there is risk of fragmenting and dislodging the thrombus to more downstream vessels, but the clot can usually still be aspirated via the same or a smaller catheter.7,9
For mechanical thrombectomy, several types of devices have been developed: (1) hydrodynamic recirculation (e.g., Hydrolyser catheter or the AngioJet and Oasis systems), (2) rotational recirculation (e.g., Amplatz, Arrow-Trerotola, or Rotarex systems), and (3) pharmacomechanical devices (Trellis Thrombectomy System).5,10 All of these tools have their own advantages and disadvantages, but to the best of our knowledge only the AngioJet has been used in the renal arteries.11 However, the renal artery is not suited to a mechanical approach because of the vessel's sharp angulation and short length. Moreover, the use of balloon catheters for thrombus expulsion may be associated with the potential risk of clot fragmentation and further embolization in the distal renal branches or lower limb arteries.4
Acute occlusion may be related to dissection or to thromboembolism. In our case, according to the intraluminal position of the guidewire and catheters, the stent must have been deployed in the true lumen, so only embolism from the stented segment was possible. Whether this came from a newly formed thrombus at the stent struts or from a preexisting one apposed to the plaque remains unclear. The angiographic appearance of the stenosis, the consistency of the clot, the anticoagulated state of the patient, and the almost immediate occurrence of the complication after initial predilation are in favor of the latter scenario.
The procedure in our case included local thrombolysis and thrombus aspiration. Local thrombolysis usually dissolves only very fresh thrombi; both the dosage of urokinase and the time of the bolus injection were empirically extrapolated from our experience with acute lower limb occlusions. The fact that no useful thrombolytic effect was seen after 10 minutes supports the hypothesis that an old mural thrombus was dislodged by predilation and stenting, leading to the occlusion of the renal artery. Furthermore, the angiographic sequence (Figure) shows that the occlusion moved distally, probably because of catheter manipulations. After thrombus aspiration was initiated, arterial blood flow was very rapidly restored.
While thrombolysis and thrombus aspiration are established methods in peripheral interventions,8 the use of abciximab for prevention of further platelet deposition was based on the large experience in the coronary field.12 Resistance to thrombolytic therapy seen in some patients with acute myocardial infarction or acute lower limb arterial thrombosis is a well-known phenomenon that may be due to the presence of old, platelet-rich clots.13 The use of glycoprotein (GP) IIb/IIIa receptor inhibition is currently used during acute coronary procedures.14 The combined use of a GP IIb/IIIa agent with low-dose fibrinolysis for peripheral arterial thrombosis has shown faster thrombus dissolution and improved amputation-free survival in single-center trials.15
As demonstrated in our case, acute occlusion during renal artery stenting can be treated successfully by percutaneous thrombus aspiration, supported by pharmacological strategies. This experience confirms our observations in acutely occluded peripheral arteries: thrombus aspiration is the most efficient method for rapidly restoring blood flow,8 which in cases of acute occlusion, is the most important factor. Prolonged thrombolysis sometimes may be necessary but diminishes the chances for preserving renal function.6
Autor: Marcello Di Valentino, MD; Mario Alerci, MD; Paolo Tutta, MD; Fabio Sartori, MD; Claudio Marone, MD; Riccardo Vandoni, MD; Felix Mahler, MD; and Augusto Gallino, MD
Fuente: Journal of Endovascular Therapy: Vol. 11, No. 4, pp. 522–526
Ultima actualizacion: 8 DE SEPTIEMBRE DE 2004