|42||Risk Factors for Percutaneous Epicardial Access Complications and Strategies for Management|
|Gregory E. Supple, MD|
Percutaneous epicardial access is now employed for an increasing number of indications. Epicardial ventricular tachycardia (VT) ablation is most often pursued in patients with nonischemic cardiomyopathy but also has a role in a subset of patients with infarct-related VT. With the appropriate technique, percutaneous epicardial access is often safely achieved; however, many prior illnesses, procedural complications, or surgeries can make safe percutaneous access difficult or impossible. Understanding and preparing for these challenges can help one achieve a safe and successful procedure.
Complications of epicardial access can be placed in two categories: (1) puncture or damage to the extracardiac organs versus (2) puncture or laceration of the heart itself or cardiac vasculature, often resulting in tamponade.
RISK FACTORS FOR DAMAGE TO THE EXTRACARDIAC ORGANS
Subsequent chapters discuss some of the common and rare complications of percutaneous epicardial access in detail. The choice of inferior or anterior approach to the pericardial space dictates some of the risks entertained during access. The inferior approach was initially described and pursued predominantly (Figure 42.1, Videos 42.1–42.3); this approach is more likely to pass under the diaphragm and therefore result in injury to the liver or gastrointestinal tract. Obese patients are more likely to require a longer needle for access via the inferior approach and may additionally have the intraabdominal organs in the way. During an access attempt with an inferior approach, it may be possible to visualize the needle indenting the stomach or colon on fluoroscopy depending on how it lies in proximity to the diaphragm. Preprocedural coronal imaging with CT or MRI may help assess this relationship up front and guide decisions about the angle of approach to avoid injury to the abdominal organs.
Figure 42.1 Right anterior oblique (RAO; Panel A) and left anterior oblique (LAO; Panel B) fluoroscopy images of contrast injection via needle entering the inferior epicardial space with contrast flowing under the inferior LV. An ICE catheter is visible in the RV outflow tract, and a quadripolar catheter is at the RV apex.
In recent years, the anterior approach has been increasingly adopted as it may help avoid such complications (Figure 42.2, Videos 42.4 and 42.5). Furthermore, it may help reduce right ventricle (RV) puncture or laceration. There are, however, reports of injury to the left internal mammary artery running just below the sternal aspect of the anterior ribs, which can result in either hemopericardium or hemothorax.1
RISK FACTORS FOR CARDIAC PUNCTURE AND TAMPONADE
The anterior approach to pericardial access may help reduce the risk of puncture of the heart or coronary veins and arteries. Regardless of the direction of approach, the important concept remains that when entering the pericardial space, a tangential angle of the needle to the cardiac surface helps reduce the risk of cardiac puncture. This may be more easily achieved with the anterior approach. Furthermore, there may be fewer cardiac vessels at risk with this approach over the RV free wall compared to the inferior approach, which commonly comes close to the posterior descending coronary artery or middle cardiac vein.
The presence of pericardial adhesions is the main additional potential limitation to safe and successful epicardial access. In many cases, pericardial adhesions can be expected such as after prior cardiac surgery. However, other situations are frequently encountered that may result in pericardial adhesions.
Prior epicardial ablation with need for repeat access is a scenario in which adhesions may be encountered. When access is uncomplicated and without significant pericardial bleeding, it may not result in significant postprocedure adhesion formation. However, when there is significant pericardial bleeding or tamponade, the likelihood of dense adhesion formation increases significantly. We have encountered dense adhesions in patients who have presented for epicardial ablation after prior attempts at epicardial access resulted in tamponade due to RV, posterior descending coronary artery, and left internal mammary artery lacerations. Additionally, we have encountered patients with pericarditis after prior ICD implantation who had dense adhesions, likely on the basis of hemopericardium from lead perforation. In our experience, if the pericardial space is washed out and thrombus formation is avoided, this may limit subsequent adhesions. However, when progressive thrombus formation is seen during management of acute hemopericardium, this is likely reflective of future adhesion development.
While a history of iatrogenic hemopericardium should increase suspicion for difficult pericardial access, similarly, a history of pericarditis or myocarditis might also pose challenges. A patient history of significant pericarditis, especially one that required anti-inflammatory treatment, should prepare the operator for difficult epicardial access if it is attempted. We have encountered this more frequently in nonischemic cardiomyopathies; however, it has been seen less commonly in post-myocardial infarction (MI) patients with Dressler’s syndrome. Figure 42.3 demonstrates the cardiac MRI findings of significant inferior epicardial delayed enhancement in a patient with myopericarditis. This patient had mild focal adhesions, but after access was achieved with an anterior approach, gentle dissection with the steerable ablation catheter allowed successful mapping over the inferior epicardial left ventricle (LV).
When a patient presents to the electrophysiology lab for epicardial access attempt with prior suspected hemo-pericardium or effusion, intracardiac echocardiography (ICE) may be helpful. If any free fluid is seen in the pericardial space (Figure 42.4), access is likely to be successful. If no fluid is seen in any of the pericardial recesses, such as along the mitral annulus, or around the right or left atrial appendage, this may raise concern for dense and diffuse adhesions.
Figure 42.2 RAO (Panel A) and LAO (Panel B) fluoroscopy images of contrast injection via needle entering the anterior epicardial space with contrast and a wire over the anterior RV. An ICE catheter is visible in the RV outflow tract, a quadripolar catheter at the anterior RV acute margin, a Decapolar catheter in the middle cardiac vein, and ICD lead on the apical RV free wall.
Figure 42.3 Cardiac MRI images of a patient who presented with acute myopericarditis and several years later required epicardial VT ablation. ECG at the time also showed inferior and inferolateral ST segment changes.
Figure 42.4 Intracardiac echocardiography of a patient with prior effusion presenting for epicardial ablation. Images of the LV show either epicardial fat or thrombus adherent to the visceral pericardium, but additionally a layer of free fluid.
PRIOR CARDIAC SURGERY