[Percutaneous aortic valve implantation - contra].
For symptomatic patients with severe aortic valve stenosis, open heart surgery for aortic valve replacement (AVR) with use of cardioplegia under cardiopulmonary bypass remains the gold standard. Cumulative surgical experience and technical improvement for more than 5 decades have led to excellent perioperative results with low mortality and morbidity. Long-term results are convincing, long-term survival is close to the average population, and durability of biological prostheses is favorable in the elderly. Even in octogenarians, AVR is feasible with acceptable results. However, in very old patients with many comorbidities, the outcome is less favorable, and many of those patients may be inoperable or carry an unacceptably high perioperative risk. Catheter-based balloon valvuloplasty (BAV) of the stenotic aortic valve was advocated 20 years ago, initially with high enthusiasm, aimed to replace AVR in older patients. However, results were unacceptably poor, and isolated BAV is only used with palliative intent today. In 2002, Cribier et al. reported of percutaneous transcatheter implantation of an aortic valve prosthesis for calcific aortic stenosis: after BAV, they implanted a metal stent graft carrying a biological valve into the aortic annulus. Despite improvement of hemodynamics, the patient died 17 weeks after implantation due to his comorbidities. Cribier and others applied percutaneous aortic valve implantation (PAVI) to inoperable, symptomatic patients with severe aortic stenosis during the next years with high early mortality and morbidity on a compassionate basis. However, with respect to the inoperable status of those patients, a treatment strategy on top of AVR, and not as an alternative, was born for usually very old patients with many comorbidities, applied as a palliation. In this early phase, cardiac surgeons were directly involved into selection of patients for PAVI, since inoperability had to be documented. Today, the indication for PAVI is about to be softened toward patients that may be candidates for open surgery as well. Not only inoperable, but also "high-risk" candidates for open surgery are recruited for PAVI now. PAVI lost its compassionate basis. Cardiac surgeons are not always involved into this decision tree anymore. For selection and justification, the perioperative risk is usually calculated with the logistic Euroscore calculator preoperatively, although it has been evidenced that this tool overestimates the operative risk by far, in contrast to the STS Score. The average Euroscore of patients selected for PAVI also decreased by time. PAVI carries the risk of several periprocedural complications, which may be life-threatening. Dislocation of the graft and embolization of the aortic orifice, aortic rupture and dissection, obstruction of coronary ostia represent devastating complications. The majority of patients after PAVI will suffer from perivalvular insufficiency; the incidence of complete AV blockade is up to 25%. The retrograde approach via the femoral artery is associated with a relatively high incidence of vascular complications to the downstream aorta, iliac and femoral arteries. The antegrade transapical approach requires intubation and thoracotomy, with the risk of bleeding from the fragile apex of the heart. Furthermore, little is known about the durability of these valves. Small catheter sizes, aimed to cross the groin vessels, do not allow the use of thick cusp tissue with high longevity. Softening the indication for PAVI is ethically not acceptable yet. Randomized, prospective studies with long-term follow-up are mandatory to evaluate the valvular longevity and the consequences of system-immanent complications of PAVI compared to AVR. Selection of patients, conduction of the procedure and treatment of potentially life-threatening complications require a team of cardiac surgeons, interventional cardiologists and anesthesiologists with a fully equipped hybrid operating room including extracorporeal circulation.
Kallenbach
Klaus
K
Klinik für Herzchirurgie, Im Neuenheimer Feld 110, 69120 Heidelberg, Germany. Klaus.kallenbach@med.uniheidelberg.de
Karck
Matthias
M
D001024:Aortic Valve Stenosis / Q000601:surgery*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000295:instrumentation* / Q000379:methods*; D006801:Humans; D018570:Risk Assessment; D012307:Risk Factors; D013673:Technology Assessment, Biomedical