Endovascular Interventions

Chapter 63 Endovascular Interventions



Niten Singh, MD, David Deaton, MD



INTRODUCTION


Endovascular therapy has changed the spectrum of vascular care that a surgeon can offer a patient. In the past, procedures such as angioplasty were believed to be reserved for short-segment stenosis and for patients in whom a bypass was not an option. The advent of stents and the technological advances made in this area have allowed endovascular options to be offered in every vascular bed. In high-risk patients in whom an open abdominal aortic aneurysm (AAA) repair was believed to be too dangerous, a stent graft can be placed with very low procedural risk.


Although believed by many to have few complications because procedures are performed through sheaths in the femoral artery, endovascular procedures are still an operative procedure in the vascular system and can be associated with similar complications as well a new variety of complications unique to catheter-based interventions. Some of these complications are described in this chapter.



INDICATIONS



• Peripheral arterial disease


OPERATIVE STEPS



Step 1 Access and contrast

Step 2 Angioplasty and stenting

Step 3 Endovascular AAA repair


Operative Procedure



Contrast Toxicity


Performance of catheter-based techniques requires the use of contrast agents and digital subtraction imagery. Contrast toxicity can affect many organs and have a profound detrimental effect. Many minor reactions of contrast have been reduced with the lower-osmolality agents now available.1 One of the major adverse effects of contrast agents is nephrotoxicity, which is generally defined as a rise in the creatinine of greater than 25% above baseline in the absence of other inciting events2 (grade 1 complication). The event usually occurs within 48 hours of the procedure. For most patients, it is nonoliguric and resolves over time. The most important risk factor for the development of contrast-induced nephropathy is preexisting renal insufficiency. Other contributing factors are dehydration, diabetes, and the amount of contrast used.


The treatment for contrast-induced nephrotoxicity is hydration, with less than 1% of patients progressing on to the need for dialysis. Prevention of nephrotoxicity is accomplished via the following methods: hydration, especially in patients with renal insufficiency, has been shown to be the most effective preventive measure; N-acetylcysteine has been shown to reduce the risk of contrast-induced nephropathy in patients with renal insufficiency3; and alkalinization of the urine has also been found to be beneficial in patients with renal insufficiency.4



Access Site Complications


Although simplistic in nature, the puncture and access of the arterial system can lead to serious complications. In infrainguinal procedures, the common femoral artery is accessed above the bifurcation of the superficial femoral artery (SFA) and the profunda femoris artery (PFA) and below the inferior epigastric artery. The access site is identified via fluoroscopic imaging and palpation of the femoral artery.5 The ideal location is over the femoral head6 (Fig. 63-1). After the procedure, manual pressure is applied to achieve hemostasis of the puncture site or a closure device is used to mechanically seal the area. Numerous complications can occur during this part of the procedure.


image

Figure 63-1 Proper position of femoral access site. A, Subtracted view displays access below the inferior epigastric artery and above the bifurcation. B, View with landmarks displays access in the common femoral artery over the femoral head.



High Arterial Puncture (Fig. 63-2)



• Consequence



Uncontrolled bleeding and retroperitoneal bleeding can occur because ineffective pressure can be applied to this area. A significant amount of blood can be lost, especially if the patient has received heparin or antiplatelet agents.

Grade 1/3 complication

image

Figure 63-2 High arterial puncture. Note the entrance of the sheath near the upper border of the femoral head.



• Repair



The retroperitoneum will often tamponade the bleeding, but the patient will have pain and likely require blood transfusions. In some instances, if the patient is unstable, the need for direct surgical repair of the artery is necessary.


• Prevention



Using anatomic landmarks and preprocedural imaging.


Low Arterial Puncture



• Consequence



Pseudoaneurysm (PSA) formation and potential distal ischemia can occur with a low puncture.

Grade 1/2/3 complication


• Repair



PSA can be monitored if it is small, and many will spontaneously regress. More recently, duplex-guided thrombin injection has been used to treat this complication. If the patient has distal ischemia from injury to the SFA or the PFA, surgical exploration and repair are mandated.


• Prevention



As described earlier and recognizing the problem prior to removing the sheath.


Poorly Angled Puncture



• Consequence



If the angle of the access needle is greater than 60 degrees, the guidewire and sheath may not pass easily. This can cause injury to the back wall of the artery and hematoma formation as well as potential dissection of the artery.

Grade 1/2 complication


• Repair



Removing the needle and manual compression and thorough pulse examination after compression.


• Prevention



The needle should not be angled at greater than 60 degrees during the access.


Access Site Thrombosis



• Consequence



Development of acute ischemia of the involved limb.

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Jun 21, 2017 | Posted by in GENERAL SURGERY | Comments Off on Endovascular Interventions

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