Early surgical intervention versus watchful waiting and outcomes for asymptomatic severe aortic regurgitation

Outcomes of Watchful Waiting Strategy and Predictors of Postoperative Prognosis in Asymptomatic or Equivocally Symptomatic Chronic Severe Aortic Regurgitation With Preserved Left Ventricular Function

BACKGROUND

The optimal surgical timing for asymptomatic or equivocally symptomatic chronic severe aortic regurgitation with preserved left ventricular ejection fraction remains controversial.

METHODS AND RESULTS

Two hundred ten consecutive patients (median age 65 years) with asymptomatic or equivocally symptomatic chronic severe aortic regurgitation and left ventricular ejection fraction ≥50% were registered. First, the treatment plans (aortic valve replacement or watchful waiting) after initial diagnosis were investigated. Then, 2 studies were set: Study A (n=144) investigated the prognosis of patients who were managed under the watchful waiting strategy after initial diagnosis; Study B (n=99) investigated the postoperative prognosis in patients who underwent aortic valve replacement at initial diagnosis or after watchful waiting. The primary outcomes were all-cause death in Study A and postoperative cardiovascular events in Study B. In Study A, 3 died of noncardiovascular causes during a median follow-up of 3.2 years. In Kaplan-Meier analysis, the survival curve was similar to that of an age-sex-matched general population in Japan. In Study B, 9 experienced the primary outcome during a median follow-up of 5.0 years. In Cox regression analysis, preoperative left ventricular end-systolic diameter enlargement (hazard ratio, 1.11; P=0.048) and left ventricular end-systolic diameter >45 mm (hazard ratio, 12.75; P=0.02) were significantly associated with poor postoperative prognosis. In Kaplan-Meier analysis, left ventricular end-systolic diameter >45 mm predicted a higher risk of the primary outcome (P <0.01).

CONCLUSIONS

Watchful waiting was achieved safely in asymptomatic or equivocally symptomatic chronic severe aortic regurgitation with preserved left ventricular ejection fraction. Preoperative left ventricular end-systolic diameter >45 mm predicted a poor postoperative outcome and may be an optimal cut-off value for surgical indication.

OUP accepted manuscript

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was: In patients with asymptomatic severe aortic regurgitation with preserved ejection fraction, is early surgery superior to watchful waiting in terms of long-term survival? Altogether, 648 papers were found using the reported search, 3 of which represented the best evidence to answer the clinical question (all level III evidence). The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. The 3 included studies comprised 469 patients. All 3 studies attempted to correct for potential baseline differences by different matching methods. As a result, a predominantly beneficial effect of early surgery on long-term survival in patients with severe asymptomatic AR and preserved LV function was observed, whereas none of the studies demonstrated a disadvantageous effect. Still, because many of the initially conservatively treated patients eventually proceed to surgery, longer term follow-up is warranted. Of note, older patients especially seem to adapt more poorly to chronic volume overload due to aortic regurgitation, making them potential candidates for a more aggressive approach. However, when a justified watchful waiting strategy is applied, close, extensive monitoring seems to be imperative, because the development of class I and II triggers seems to lead to improved survival.

Optimal Management of Chronic Severe Aortic Regurgitation - How to Determine Cutoff Values for Surgical Intervention?

Aortic regurgitation (AR) is a common valvular heart disease, but the optimal timing of surgical intervention remains controversial. In the natural history of chronic severe AR, sudden death is rare, and the annual mortality rate is comparatively low. Considering the hemodynamic features of combined volume and pressure overload and long-term compensation in patients with chronic AR, symptoms related to AR do not frequently occur. Therefore, the progression of left ventricular (LV) dysfunction is a key factor in determining the timing of surgical intervention in patients with severe chronic AR. In addition to symptoms, an ejection fraction <50% and an LV endsystolic diameter (LVESD) >45 mm are appropriate cutoff values for surgical intervention in Japanese patients, whereas LV end-diastolic diameter is not a good indicator. An LVESD index of 25 mm/m²is controversial, because adjusting for body size may cause overcorrection in Japanese patients who have a small body size compared with Westerners. Accumulation of data from the Japanese population is indispensable for establishing guidelines on optimal management of patients with chronic AR.

Optimizing Timing of Valve Intervention in Patients With Asymptomatic Severe Valvular Heart Disease

The management of valvular heart disease has changed dramatically over the past decade with advances in cardiac imaging, the use of novel biomarkers, and the development of transcatheter valve repair and replacement technology. International society guidelines have kept pace to provide recommendations for diagnosis, follow-up, and timing of intervention. The most challenging patient cohort for clinicians are patients with asymptomatic severe disease in whom the optimal timing of intervention can be ill-defined. It is a fine balance between the risks of early intervention on asymptomatic patients and improving patient outcomes by preventing long-term cardiac complications. The key in optimal patient management is gathering the necessary information on patient risk and combining that with the risk, efficacy, and durability of valve interventions to arrive at the appropriate timing for intervention. This group of patients will be the focus of this review as we delve into the natural history, recommended follow-up, and indications for intervention in patients with degenerative aortic and mitral valve disease.

Timing of intervention in asymptomatic patients with valvular heart disease

Current management of valvular heart disease (VHD) seeks to optimize long-term outcome by timely intervention. Recommendations for treatment of patients with symptoms due to severe valvular disease are based on a foundation of solid evidence. However, when to intervene in asymptomatic patients remains controversial and decision requires careful individual weighing of the potential benefits against the risk of intervention and its long-term consequences. The primary rationale for earlier intervention is prevention of irreversible left ventricular (LV) myocardial changes that might result in later clinical symptoms and adverse cardiac events. A number of outcome predictors have been identified that facilitate decision-making. This review summarizes current recommendations and discusses recently published data that challenge them suggesting even earlier intervention. In adults with asymptomatic aortic stenosis (AS), emerging risk markers include very severe valve obstruction, elevated serum natriuretic peptide levels, and imaging evidence of myocardial fibrosis or increased extracellular myocardial volume. Currently, transcatheter aortic valve implantation (TAVI) is not recommended for treatment of asymptomatic severe AS although this may change in the future. In patients with aortic regurgitation (AR), the potential benefit of early intervention in preventing LV dilation and dysfunction must be balanced against the long-term risk of a prosthetic valve, a particular concern because severe AR often occurs in younger patients with a congenital bicuspid valve. In patients with mitral stenosis, the option of transcatheter mitral balloon valvotomy tilts the balance towards earlier intervention to prevent atrial fibrillation, embolic events, and pulmonary hypertension. When chronic severe mitral regurgitation is due to mitral valve prolapse, anatomic features consistent with a high likelihood of a successful and durable valve repair favour early intervention. The optimal timing of intervention in adults with VHD is a constantly changing threshold that depends not only on the severity of valve disease but also on the safety, efficacy, and long-term durability of our treatment options.

Early Surgery in Valvular Heart Disease

The burden of valvular heart disease (VHD) is increasing with age, and the elderly patients with moderate or severe VHD are notably common. When to operate in asymptomatic patients with VHD remains controversial. The controversy is whether early surgical intervention should be preferred, or a watchful waiting approach should be followed. The beneficial effects of early surgery should be balanced against operative mortality and long-term results. Indications of early surgery in each of the VHD will be discussed in this review on the basis of the latest American and European guidelines.