HISTORY AND RATIONALE OF THE PROCEDURE
Aortic stenosis (AS) is the most common acquired valvular disease in adults.1 The incidence of AS has steadily increased along with population life expectancy and age, affecting almost 5% of patients over the age of 75 years.2 The most common cause of valvular AS in adults is calcification of a normal trileaflet valve or a congenital bicuspid valve.3 Severe symptomatic AS has a poor prognosis when treated medically, with a mortality of almost 80% at 2 years.4 Surgical aortic valve replacement (SAVR) is currently the standard of care and accepted to alleviate symptoms and prolong survival; however, up to one-third of patients are denied SAVR because of prohibitive surgical risk (eg, advanced age, significant left ventricular dysfunction).5
In 2002, Cribier and colleagues6 successfully performed the first transcatheter aortic valve replacement (TAVR) in an elderly inoperable patient for the treatment of severe AS. This approach marked the feasibility of percutaneous valve implantation, and TAVR has emerged as a less invasive alternative to conventional SAVR.7 Results from the Placement of Aortic Transcatheter Valves (PARTNER) trial have allowed TAVR to become the standard of care for extremely high-risk or “inoperable” patients, and TAVR is a valid alternative to surgery for selected high-risk but “operable” patients with symptomatic AS.8,9 TAVR has been performed for over 10 years with >100,000 implantations worldwide, and this innovative technology has allowed a paradigm shift in the treatment of AS.10
INDICATIONS FOR TREATMENT
TAVR is recommended for patients with symptomatic, severe, calcific stenosis of a tricuspid aortic valve who have predicted survival >12 months and either prohibitive surgical risk (defined by >50% estimated risk of mortality or irreversible morbidity at 30 days, frailty, prior cobalt chest irradiation, porcelain aorta, coronary bypass graft adhesion to the posterior sternum preventing safe reentry into the chest, or severe pulmonary or hepatic disease) or high surgical risk (Society of Thoracic Surgeons [STS] mortality risk ≥8% with predicted actual mortality >15%).11,12 Trials are ongoing to evaluate TAVR in a medium-risk population (STS mortality risk 3%-8%; PARTNER II trials).
AVAILABLE BALLOON-EXPANDABLE VALVES
Currently, the most data available for TAVR are based on the balloon-expandable SAPIEN valves (Edwards Lifesciences, Irvine, CA; Fig. 42-1). The Edwards SAPIEN transcatheter heart valve system has been used extensively worldwide and was used in the PARTNER I trial.7 Based on this trial, the SAPIEN valve was the first transcatheter aortic valve to be granted approval by the US Food and Drug Administration (FDA) in November 2011 for use in surgically inoperable patients and in 2012 for use in surgically high-risk patients in the United States.12 The Edwards SAPIEN consists of a trileaflet, bovine pericardial valve mounted on a stainless steel stent with a polyethylene terephthalate skirt and seals at the aortic ...