- The number of diagnostic and therapeutic interventions performed outside of the operating room requiring anesthesia services has increased exponentially over the past 10 years. Anesthesiologists of all varieties are engaged in doctor's offices, ambulatory surgery centers, and endoscopy suites. Although cardiac anesthesiologists are most often involved with highly invasive heart surgery procedures, they too find an increasing part of their practice spent outside of the operating theatre. Evermore complicated catheter-mediated procedures are completed in ever sicker patients in the cardiac catheterization and electrophysiological laboratories. Common procedures include: diagnostic coronary angiography, coronary stenting, percutaneous closure of septal defects, electrophysiology (EP) studies, arrhythmia ablations, and implantations of pacemakers/cardioverter defibrillators. Also, as was previously discussed, catheter-based valve replacements and repairs are also being performed.
Cardiac EP is the medical specialty devoted to the diagnosis and treatment of abnormal heart rhythms. It involves diagnostic electrophysiology testing, radiofrequency catheter ablation, and implantation of antiarrhythmic devices such as pacemakers and cardio-defibrillators.
Advanced medical research, new technology, an aging population, and the prolonged survival of very ill patients have added to the complexity of procedures performed and management of patients requiring EP therapies.1-4 The anesthesiologist is frequently consulted in both the cardiac catheterization and electrophysiology laboratories to help manage patients with severe coronary, valvular, and vascular diseases. Patients can experience hemodynamic perturbations secondary to arrhythmias, poor baseline ventricular function, or procedurally related iatrogenic myocardial perforation and tamponade. Anesthesiologists are called upon not only to maintain patient comfort during these procedures but also to be available to resuscitate the patient should hemodynamic or airway complications present.1 Consistent guidelines have yet to be established regarding the nature of procedures and the complexity of patients which warrant the involvement of the anesthesia team.
Procedures that might involve the anesthesia team include:
Coronary artery stenting is used in the treatment of ST-elevation myocardial infarction, in-stent restenosis, stenting of saphenous vein grafts, and treatment of chronic coronary artery occlusions. Most of these procedures are performed under moderate sedation given by the nursing staff of the catheterization laboratory. Involvement of the anesthesia team typically is requested when the patient is hemodynamically unstable or there is a need for emergent airway management.5
Percutaneous ventricular assist devices (VADs): Until recently, intra-aortic balloon contrapulsation with inotropic support was the main therapeutic option for supporting the failing ventricle. Implantable ventricular assist devices have been and are being used now as "bridge to recovery or to transplantation" for the failing ventricle. Implantable VADs are placed in the cardiac surgery operating room. However, during the past few years a number of percutaneous designs have appeared which can be placed in the catheterization laboratory to provide emergent support for the failed heart.
Two percutaneous ventricular assist devices (PVAD) that can be placed in the cardiac catheterization laboratory are the TandemHeart (Cardiac Assist, Inc., Pittsburg, PA) and the Impella Recover LP 2.5 and 5.0 (Abiomed Inc., Danvers, MA). Both of these devices can ...