The Utility of Atrioventricular Pacing via Pulmonary Artery Catheter During Transcatheter Aortic Valve Replacement

Abstract

HE DEVELOPMENT OF TRANSCATHETER aortic valve replacement (TAVR) has led to the treatment of calcific aortic stenosis in patients whose condition might otherwise be considered inoperable if relegated to traditional aortic valve surgery. Although the ability to replace a patient’s aortic valve in this manner represents an important advancement in the treatment of aortic valve disease, there remain many challenges associated with successfully performing the procedure. One of these challenges is the ability to maintain hemodynamic stability during valve positioning and then recover stability after its deployment. Several factors can complicate this mission. The most obvious relate to the patient’s underlying aortic valve pathology as well as other concomitant cardiac disease. During valve positioning, the interposition of the deployment system across an already compromised aortic valve will further limit the native valve’s effective orifice area and also can promote regurgitation. Mechanical or functional mitral regurgitation also may occur during this process, producing additional strain on the myocardium. The cardiovascular system is further burdened by the need for cardiac “stand-still” during valve deployment. This is achieved by inducing rapid ventricular pacing (V-pacing). Hemodynamic recovery after this may be difficult, particularly if the pacing runs are protracted or successive. Delayed recovery can promote further myocardial ischemia, initiating a downward spiral that may prove intractable without significant intervention, including the need for mechanical circulatory support. Management can be complicated further by the development of conduction abnormalities (CA) after TAVR. This association has been well documented, but most of the literature has discussed them in regard to postoperative management, particularly the potential need for permanent pacemaker (PPM) placement. 1–4 However, CAs typically present during or immediately after valve deployment 5 and their acute hemodynamic effects have, in contrast, largely been ignored in published reports. This may be an important omission because the acute loss of atrioventricular (AV) synchrony may be tolerated poorly given the common association of ventricular hypertrophy and diastolic dysfunction in patients with aortic stenosis. In addition, because of the percutaneous nature of the procedure there are limited intraoperative rhythm management options available should the CA be associated with hemodynamic instability. Because of these concerns, all patients undergoing TAVR at this institution have percutaneous right atrial (RA) and right ventricular (RV) endocardial pacing wires placed via a specialized pulmonary artery catheter (PAC), unless they already have a PPM or have pre-existing atrial fibrillation (Fig 1). What follows is the discussion of a case that exemplifies the important benefits of this technique. CASE A 91-year-old woman with progressive dyspnea on exertion secondary to critical aortic stenosis presented for TAVR. The patient’s medical history also was significant for coronary artery disease with drug-eluting stents placed 2 years earlier, non–insulin-dependent diabetes mellitus, and temporal arteritis. Preoperative echocardiography revealed normal left ventricular function but with severe concentric hypertrophy, moderate mitral valve stenosis and regurgitation, and moderate-to-severe tricuspid regurgitation. The baseline electrocardiogram (ECG) was notable for sinus rhythm at 76 beats/min with an incomplete right bundle-branch block (RBBB) and a PR interval of 156 ms. A transaortic surgical approach was chosen because of the presence of a small and tortuous aorta with significant atheroma as well as the patient’s small body size, the combination of which limited both transapical and transfemoral deployment. After the induction of general anesthesia, a thermodilution PAC with two additional ports allowing the introduction of endocardial pacing wires into both the RA and RV (A-V Paceport Catheter, Edwards Lifesciences Corp., Irvine, CA) was inserted through a 9- French introducer sheath that had been placed into the right internal jugular vein (IJV). In order to properly position the pacing wires, the PAC was advanced while the pressure waveforms of both the catheter tip and the RV Paceport orifice were simultaneously monitored. Once the catheter tip entered the pulmonary artery (PA), it was further advanced until an RV pressure waveform was seen from the RV Paceport orifice, which indicated that this port had crossed the tricuspid