Chronic Severe Aortic Regurgitation: Should We Lower Operating Thresholds?

Abstract

September 24, 2019 1045 Milind Y. Desai, MD Lars G. Svensson, MD, PhD C hronic severe aortic regurgitation (AR) results in left ventricular (LV) volume and pressure overload, initially leading to compensatory but eventually detrimental myocardial changes, with patients remaining asymptomatic for a long time. Over time, the LV fails, resulting in a reduction in left ventricular ejection fraction (LVEF) and symptom onset. Current American College of Cardiology/American Heart Association guidelines recommend aortic valve (AV) surgery in symptomatic patients or those with depressed LVEF (Class I indication).1 They also recommend AV surgery (Class II indication) in asymptomatic patients with preserved LVEF and a significantly dilated LV.1 However, these recommendations were derived from smaller studies, performed at a time when surgical outcomes were poorer. With significant improvements in imaging, advanced surgical techniques (minimally invasive surgery, AV repair, improved intraoperative myocardial protection and postoperative care), surgical outcomes have improved considerably. Multiple recent reports have suggested that the previously recommended LV size thresholds for recommending AV surgery may be too conservative.2–4 Hence, is it time for the current guidelines to be revisited in terms of making recommendations for earlier AV surgery for asymptomatic patients with severe AR and a preserved LVEF? In a study of 1417 patients treated at a high-volume center, patients with ≥III+ AR (±concomitant aortopathy) and preserved LVEF (87% asymptomatic and 13% with mild symptoms) demonstrated significantly improved longer-term survival following AV surgery (n=933, 58% with concomitant aortic replacement, 0.2% in-hospital mortality for isolated AV surgery) which approximates that of a normal age-gender-matched US population (Figure 1A).2 The finding was independent of the indexed LV end-systolic dimension (iLVESD) at which the patient was operated. Furthermore, in the 484 nonoperated patients, those with iLVESD ≤2.0 cm/m2 had an excellent 5-year survival; however, the risk of death increased once iLVESD exceeded 2.0 cm/m2 (Figure 1B). These findings were further corroborated in an independent sample of 356 patients undergoing AV surgery (1.1% in-hospital mortality).3 In the study, adjusted 10-year survival was better among patients without operative triggers (89±4%) or with Class II triggers (85±6%) than in patients with Class I triggers (71±4%, P<0.01). In addition, the authors also demonstrated that the mortality started to increase for LVEF <55% and iLVESD >2.0 to 2.2 cm/m2 (Figure 1C). A third independent report on 748 patients (of which 361 underwent AV surgery with a <1% in-hospital postoperative mortality) with chronic severe AR also demonstrated that operating for class I indication was associated with worse longer-term mortality as compared to Class II indication.4 In addition, iLVESD beyond which mortality increased was also 2 cm/m2 (Figure 1D). © 2019 American Heart Association, Inc. ON MY MIND