Noncardiac surgery in adults with aortic stenosis

INTRODUCTION — Risk models have identified severe aortic stenosis (AS) as a major clinical predictor of adverse outcomes [1]. Population studies from the United States and Europe have reported AS in approximately 1 to 2 percent of individuals 65 to 75 years old, with prevalence increasing to 3 to 8 percent in individuals ≥75 years old and 18 percent in those >90 years old [2-8]. In the Helsinki Aging study, nearly 3 percent of the individuals between 75 and 86 years of age had critical AS [3]. Concurrent cardiovascular disease has been identified in more than 50 percent of patients with AS >70 years and in 65 percent in those >80 years [9,10]. (See "Clinical manifestations and diagnosis of aortic stenosis in adults" and "Evaluation of cardiac risk prior to noncardiac surgery" and "Valvular heart disease in older adults", section on 'Underlying atherosclerosis'.)

The presence of valvular disease has potentially important implications for perioperative management as well as perioperative risk. Preoperative considerations and postoperative management of patients with native AS undergoing noncardiac surgery will be reviewed here.

Intraoperative management of patients with AS is reviewed separately. (See "Anesthesia for noncardiac surgery in patients with aortic or mitral valve disease".)

PATHOPHYSIOLOGY — AS results in fixed obstruction to left ventricular (LV) emptying. The stenotic process is usually gradual in onset and progression, giving the heart ample opportunity to adapt. The LV myocardium hypertrophies over time, resulting in the generation of greater pressure during systole, which forces blood past the fixed mechanical obstruction. As a result, the cardiac output and LV end-diastolic volume are maintained and patients can remain asymptomatic for a prolonged period of time, even with severe AS. (See "Clinical manifestations and diagnosis of aortic stenosis in adults" and "Natural history, epidemiology, and prognosis of aortic stenosis".)

However, the chronic pressure overload state that results in the compensatory concentric LV hypertrophy also reduces the compliance of the LV. As a result, diastolic dysfunction develops over time, the end diastolic pressure of the LV increases, and patients eventually develop symptoms of dyspnea. The concentric hypertrophy also reduces coronary flow reserve, rendering the patient more susceptible to chest pain from ischemia in situations of increased myocardial oxygen demand, even in the absence of obstructive coronary artery disease [11]. In addition, due to fixed obstruction of the LV outflow tract, decreases in systemic vascular resistance can result in hypotension with subsequent ischemia from reduced coronary perfusion, ultimately manifesting in presyncope or syncope. (See "Clinical manifestations and diagnosis of aortic stenosis in adults".)

Therefore, rapid clinical deterioration can occur in patients even with asymptomatic AS during the hemodynamic stress associated with both the anesthetic and surgical stress of noncardiac surgery (as well as other states that require augmentation of cardiac output, such as infection, anemia, or pregnancy).

PREOPERATIVE ASSESSMENT

Key steps — The following are key steps in the management of patients with suspected AS who need noncardiac surgery:

●Evaluation of symptoms and signs of cardiac disease

●Preoperative echocardiographic assessment of AS severity and LV function

●Careful evaluation for coexisting coronary artery disease (CAD) and other cardiac risk factors (table 1)

●Estimation of the risk of noncardiac surgery

The above evaluation will enable recognition of AS, determination of its severity, and identification of any concomitant cardiac disease.

Recognition of AS — Recognition of AS is a key step in preoperative assessment. Many adverse events occur because the diagnosis of AS was not known to the surgical team. Preoperative echocardiography should be performed for evaluation of any murmur that is not clearly benign based on history and physical exam.

AS may be initially recognized on physical examination by the presence of a systolic "ejection" murmur (movie 1A-B). A functional murmur should be distinguished from a pathologic murmur with a careful physical examination that includes cardiac maneuvers (see "Auscultation of cardiac murmurs in adults" and "Physiologic and pharmacologic maneuvers in the differential diagnosis of heart murmurs and sounds"). The physical examination may also reveal one or more associated findings. These findings are briefly summarized here and are discussed in detail separately. (See "Clinical manifestations and diagnosis of aortic stenosis in adults", section on 'Physical examination'.)

The murmur of aortic valve sclerosis, a common and more benign valvular abnormality seen in older individuals, is also a midsystolic murmur. In general, the murmur is brief and not very loud. A normal carotid pulse and normal S2 usually confirm the absence of AS. (See "Aortic valve sclerosis and pathogenesis of calcific aortic stenosis".)

Studies evaluating the precision and accuracy of the clinical examination found that four findings were useful for diagnosis of AS [12-14]:

●A slow rate of rise and reduced peak in the carotid pulse

●Mid to late peak intensity of the murmur

●Maximal murmur intensity at the second right intercostal space

●Reduced intensity of the second heart sound or single S2

Echocardiography enables assessment of disease severity and is necessary since none of the physical findings have both a high sensitivity and high specificity for severe valvular obstruction [12,13]. Although classic findings are helpful in identifying patients with significant AS, the physical examination is less useful for estimating hemodynamic severity.

Evaluation of AS severity — Evaluation of the AS patient includes history, physical examination, echocardiography, and assessment of any concomitant cardiovascular disease, as discussed in detail separately. (See "Clinical manifestations and diagnosis of aortic stenosis in adults" and "Clinical manifestations and diagnosis of low gradient severe aortic stenosis" and "Aortic valve area in aortic stenosis in adults" and "Echocardiographic evaluation of the aortic valve".)

As noted in the 2014 American College of Cardiology/American Heart Association (ACC/AHA) perioperative guideline, patients with clinically suspected moderate or greater degrees of valvular stenosis or regurgitation should undergo preoperative echocardiography if there has been either 1) no prior echocardiography within one year or 2) a significant change in clinical status or physical examination since the last evaluation [1].

The 2020 ACC/AHA valvular heart disease guideline classifies valvular heart disease into one of four stages (A to D) based on valve morphology, the presence or absence of symptoms, hemodynamic severity of disease, and the impact of the valve lesion on ventricular function. Those with stage A AS are considered at risk for progression (eg, those with bicuspid aortic valve or aortic sclerosis); stage B, mild to moderate severity disease, but asymptomatic; stage C1, severe disease, but asymptomatic and compensated right and LV function; stage C2, severe, but asymptomatic with decompensation of right and/or LV function; and stage D, hemodynamically severe and symptomatic (table 2) [15]. Though symptomatic severe AS is usually associated with a high gradient (stage D1), severe AS may also exist with a low gradient due to either low flow associated with reduced LV ejection fraction (stage D2) or with normal LV ejection fraction associated with normal flow or paradoxical low flow (D3). (See "Clinical manifestations and diagnosis of aortic stenosis in adults" and "Clinical manifestations and diagnosis of low gradient severe aortic stenosis".)

Evaluation of CAD — We recommend assessment of the presence of CAD in patients with AS prior to elective noncardiac surgery when the patient is symptomatic with chest pain or angina equivalent, has evidence of heart failure (HF) that has not been previously assessed, or has evidence of a recent acute coronary syndrome. In patients requiring urgent or emergency surgery, the evaluation for obstructive CAD should not delay a necessary noncardiac operation. (See "Evaluation of cardiac risk prior to noncardiac surgery".)

In patients without valvular heart disease, the preoperative assessment for CAD is made on the basis of symptoms and functional capacity. Given the physiologic changes that occur in patients with AS (LV hypertrophy, diastolic dysfunction, alterations in coronary flow reserve), the cause of cardiac symptoms (ie, obstructive CAD versus valvular disease) can be difficult to differentiate. (See "Evaluation of cardiac risk prior to noncardiac surgery".)

Further complicating this issue is the frequency of concomitant AS and CAD, with the prevalence of both increasing with age. Among older patients with symptomatic AS, the prevalence of CAD is 40 to 50 percent in those with typical angina and 20 percent in those without chest pain. Even in patients with AS who are less than 40 and have no chest pain and no coronary risk factors, the prevalence of CAD may be as high as 5 percent [16-19]. (See "Clinical manifestations and diagnosis of aortic stenosis in adults".)

The following considerations guide the choice of test in patients with AS undergoing evaluation for CAD:

●Given the importance of determining the presence of CAD, coronary angiography remains the most appropriate method for the definitive diagnosis of CAD in patients with severe AS with risk factors or symptoms that might be due to coronary disease. (See "Indications for valve replacement for high gradient aortic stenosis in adults", section on 'Coronary angiography prior to valve surgery'.)

Furthermore, if echocardiographic assessment is inconclusive, a left heart catheterization can provide direct hemodynamic measurements of the aortic valve gradient. Since there is some risk of cerebral embolization associated with crossing a calcified stenotic aortic valve [20,21], retrograde catheterization of the aortic valve is performed only when needed.

●Electrocardiogram (ECG) stress testing alone is generally not sufficient for evaluation of CAD in patients with AS [15]. The resting and exercise ECG in patients with valvular heart disease frequently shows ST-segment changes due to LV hypertrophy, LV chamber dilatation, or bundle-branch block, which reduces the accuracy of the ECG at rest and during exercise for the diagnosis of concomitant CAD. In addition, caution should be used when exercising patients with severe AS, as postexercise vasodilatory responses can dramatically reduce preload and result in hemodynamic decompensation.

●Dobutamine stress echocardiography or vasodilator radionuclide stress testing may be helpful in patients with mild or moderate AS. Although data are limited, small studies suggest that vasodilator radionuclide stress testing may be useful in patients with moderate or severe AS [22-24]. A study found that vasodilator stress in patients with severe AS was associated with an increased risk of a >20 mmHg fall in systolic blood pressure and only moderate diagnostic accuracy (sensitivity of 77 percent and specificity of 69 percent) for detection of CAD, compared with coronary angiography [25]. In selected patients with a low to intermediate pretest probability of CAD, contrast-enhanced coronary computed tomographic angiography is an option. (See "Stress testing for the diagnosis of obstructive coronary heart disease" and "Selecting the optimal cardiac stress test" and "Clinical use of coronary computed tomographic angiography".)

Stress testing is also used for purposes other than evaluation of CAD in specific populations of patients with AS. The use of exercise testing to evaluate asymptomatic patients with AS and the use of low-dose dobutamine stress testing in patients with low flow, low gradient AS are discussed separately. (See "Clinical manifestations and diagnosis of aortic stenosis in adults", section on 'Asymptomatic sedentary patients' and "Clinical manifestations and diagnosis of low gradient severe aortic stenosis", section on 'Low-dose dobutamine stress echocardiogram'.)

Estimation of risk of noncardiac surgery

Risk factors — The risk of perioperative cardiac complications from noncardiac surgery in patients with AS varies with the severity of AS, the presence of cardiac symptoms, and the presence of other cardiac risk factors (table 1), including ischemic heart disease and moderate or severe mitral regurgitation [26,27] (see 'Evaluation of CAD' above). The risk of noncardiac surgery is also dependent upon the risk category of the surgical procedure; minor procedures with local anesthesia entail less risk. Perioperative complications include myocardial infarction (MI), hypotension, HF, arrhythmias, and death.

General issues related to the estimation and management of cardiac risk prior to noncardiac surgery, including initial risk assessment, the role of noninvasive testing and possible cardiac catheterization, and the indications for beta blocker and statin therapy, are discussed separately (see "Evaluation of cardiac risk prior to noncardiac surgery" and "Management of cardiac risk for noncardiac surgery"). However, most preoperative risk models do not include AS as a risk factor because this condition was not adequately represented in the populations from which these risk assessment tools were generated.

The perceived risk of complications in AS patients likely contributes to this underrepresentation, as patients are either deemed ineligible or referred for aortic valve replacement or valvotomy prior to surgery [28]. While the risk of adverse outcomes after major surgery in patients with valvular heart disease was reported as early as the 1960s [29], the association of AS with cardiac complications of noncardiac surgery was first established in the 1977 study that led to the initial Goldman cardiac risk index of noncardiac surgical procedures [30,31]. This study, like many that have followed, failed to distinguish between different severities of AS or between asymptomatic and symptomatic patients.

For example, perioperative risk of noncardiac surgery was compared in a 2005 study of 5149 AS patients identified based on International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes with severity not specified and 10,284 controls from the National Hospital Discharge Survey database [32]. The risk of MI was significantly higher in patients with AS compared with controls (3.9 versus 2.0 percent), and the presence of AS conferred a higher risk of MI even after correcting for sex, CAD, hypertension, and diabetes mellitus in a multivariate logistic regression model (odds ratio 1.55, 95% CI 1.27-1.9).

Lack of stratification of AS severity or symptomatology and heterogeneity in their evaluation and reporting have led to estimates as wide as 10 to 30 percent for the risk of cardiac complications after noncardiac surgery. These figures may complicate decision-making for clinicians and lead to unwarranted delay or cancellation of essential surgical procedures.

Later studies have focused on stratifying risk based on AS severity and symptoms, as illustrated by the following studies:

●In a retrospective study from the Netherlands of 108 patients with moderate or severe AS and 216 controls [26], a composite outcome of perioperative mortality and nonfatal MI not only occurred more frequently in AS patients than controls (14 versus 2 percent) but also in those with severe AS compared with moderate AS (31 versus 11 percent).

●A Mayo Clinic Scottsdale study compared perioperative outcomes of noncardiac surgery for 30 patients with asymptomatic severe AS with those for 60 controls with mild to moderate AS [33]. Postoperative events were more frequent in those with severe AS compared with those with mild to moderate AS, although the result did not reach statistical significance (33 versus 23 percent; p = 0.06).

●In a study of 244 patients with severe AS and 390 patients with moderate AS undergoing noncardiac surgery at the Cleveland Clinic from 1998 to 2009 [27]:

•Mortality was 2.1 percent for AS patients compared with 1.0 percent in controls without AS. Likewise, postoperative MI was more frequent in patients with AS compared with controls (3.0 versus 1.1 percent).

•When stratified by symptomatology, patients with symptomatic severe AS had mortality of 2.8 percent as compared with 1.2 percent in those with asymptomatic severe AS. Similarly, postoperative MI occurred in 5.6 percent of patients with symptomatic severe AS and 3.5 percent in patients with asymptomatic severe AS.

●An analysis of 256 patients with severe AS undergoing intermediate- or high-risk surgery at the Mayo Clinic from 2000 to 2010 yielded the following results [34]:

•There was no significant difference in 30-day mortality (5.9 versus 3.1 percent) in patients with severe AS compared with controls matched for age, sex, and year of surgery. However, mortality was significantly higher in patients with symptomatic severe AS compared with those with asymptomatic severe AS (9.4 versus 3.3 percent).

•Patients with severe AS experienced more major adverse cardiovascular events in 30 days (18.8 versus 10.5 percent), an outcome dominated by HF. Major adverse cardiovascular events were more frequent in symptomatic AS patients than in asymptomatic AS patients (28.3 versus 12 percent).

●In multivariable analysis, the following were predictors of postoperative death: emergency surgery (the strongest predictor), atrial fibrillation, and serum creatinine levels of >2 mg/dL.

Finally, a systematic review and meta-analysis of nine studies of severe AS (including most of those listed above) with 29,327 participants found no difference in postoperative mortality between AS patients and controls. However, there was an increase in the composite adverse outcome as defined in each individual study, with a risk ratio (RR) of 2.30 (95% CI 1.33-3.97). When looking at patients with AS of any severity, the risk ratio versus control was lower (RR 1.64, 95% CI 1.23-2.19). The lowest risk of composite adverse outcome was seen in patients with asymptomatic AS (RR 1.59, 95% CI 1.19-2.12, p = 0.002) [35].

Stratification of AS by severity and symptomatology has been incorporated into the ACC/AHA and European Society of Cardiology guidelines. The former recommend (class IIa) "moderate-risk elective noncardiac surgery with appropriate intraoperative and postoperative hemodynamic monitoring" in patients with asymptomatic severe AS, whereas the latter recommend management of severe AS patients based on the presence or absence of symptoms. (See 'Society guideline links' below.)

Increased risk of bleeding — Patients with moderate to severe AS have a bleeding tendency due to an acquired von Willebrand syndrome, which may increase the risk associated with noncardiac surgery [36]. Specifically, Heyde syndrome describes the increased risk of gastrointestinal bleeding from angiodysplasia associated with AS [37]. (See "Clinical manifestations and diagnosis of aortic stenosis in adults", section on 'Bleeding tendency'.)

PREOPERATIVE MANAGEMENT

Decisions before noncardiac surgery — The above preoperative assessment will enable estimation of the risk of noncardiac surgery and determination of whether preoperative valve intervention is indicated. The necessity of the proposed noncardiac surgery should be carefully evaluated.

As noted in both the 2020 American Heart Association/American College of Cardiology (AHA/ACC) valve guidelines and the 2017 European Society of Cardiology (ESC) valve guidelines, low or moderate-risk elective noncardiac surgery with appropriate intraoperative monitoring and postoperative hemodynamic monitoring (including right heart catheter and/or intraoperative transesophageal echocardiography) is reasonable to perform in patients with asymptomatic severe AS [15,38]. As discussed above, observational data suggest that, with careful management, selected patients with AS, particularly those with asymptomatic disease and without significant CAD or other valvular disease, can undergo noncardiac procedures with an acceptable risk [26,27,32-34,39,40]. The anesthesia team should be aware of the presence and severity of AS. (See "Anesthesia for noncardiac surgery in patients with aortic or mitral valve disease", section on 'Aortic stenosis'.)

Patients with indications for AVR — For patients with AS who have indications for aortic valve replacement (AVR by surgical AVR [SAVR] or transcatheter aortic valve implantation [TAVI]) such as symptomatic severe AS, stage D, or asymptomatic severe AS with LV ejection fraction <50 percent), we recommend postponing elective noncardiac surgery since these conditions are significant risk factors for perioperative morbidity and mortality [15,41,42]. The indications for AVR (SAVR or TAVI) are the same as in the absence of planned noncardiac surgery [1,15]. (See "Indications for valve replacement for high gradient aortic stenosis in adults".)

●The choice between SAVR or TAVI is discussed separately. (See "Choice of intervention for severe calcific aortic stenosis".)

SAVR prior to noncardiac surgery is not always feasible, as some patients require an urgent noncardiac procedure, some may be at high risk for adverse outcomes from valvular surgery, and some may decline aortic valve surgery.

In a registry-based cohort study of 2238 patients undergoing TAVI between 2012 and 2020, 300 patients subsequently underwent noncardiac surgery (elective for 160 patients and urgent/emergency for 140 patients) [43]. The risk of a 30-day adverse clinical event after noncardiac surgery was approximately 20 percent, with a 30-day mortality rate of nearly 10 percent. Baseline patient characteristics and timing, urgency, and surgical risk category were not associated with composite outcomes of death, stroke, MI, or bleeding. However, suboptimal device performance, such as paravalvular regurgitation or prosthesis-patient mismatch, was associated with an increased risk of 30-day adverse outcomes.

●Options for patients who are unable to undergo aortic valve intervention include proceeding directly with the noncardiac surgery with careful perioperative management. The role of balloon aortic valvuloplasty (BAV) in these patients is uncertain. (See "Choice of intervention for severe calcific aortic stenosis".)

•Limited observational data suggest that with careful perioperative hemodynamic monitoring and care appropriate for the valve lesion, including postoperative intensive care unit management, selected patients with severe AS who are not candidates for or decline AVR or TAVI can undergo noncardiac procedures at an acceptable risk, particularly in the absence of significant CAD [26,27,32-34,39,40].

•The role of percutaneous BAV in patients with severe AS requiring noncardiac surgery is uncertain and declining as routine availability of TAVI has increased. The use of percutaneous BAV is limited in older adults with AS because complications (eg, stroke, acute aortic regurgitation, and MI) occur in approximately 10 to 20 percent of patients. Restenosis and clinical deterioration occur in most cases within 6 to 12 months. Data are limited on the efficacy of this approach in general and as applied to preparation for noncardiac surgery (see "Percutaneous balloon aortic valvotomy for native aortic stenosis in adults"):

Two small studies, each with only seven patients who had symptomatic AS, evaluated the outcomes in patients who underwent BAV prior to noncardiac surgery [44,45]. There were no deaths, strokes, or conduction abnormalities in either series. One patient developed a pseudoaneurysm of the femoral artery.

The outcomes were not as good in a report of 15 patients with symptomatic severe AS who underwent either noncardiac surgery or an invasive diagnostic procedure following BAV [46]. There were adverse outcomes in five patients, including one fatality. Among the 14 patients who survived BAV, there were no adverse surgical outcomes associated with either the noncardiac surgery or subsequent invasive diagnostic procedure.

The 2020 AHA/ACC valvular guidelines do not recommend routine BAV in the preoperative setting, with the possible exception of use in critically ill patients as a bridge to SAVR or TAVI. The 2017 European Society of Cardiology (ESC) guidelines note that TAVI (or BAV) may be considered in selected patients with symptomatic AS at high risk for adverse outcomes with valve surgery [42].

INTRAOPERATIVE MANAGEMENT — Intraoperative management for patients with AS undergoing noncardiac surgery is discussed separately (table 3). (See "Anesthesia for noncardiac surgery in patients with aortic or mitral valve disease", section on 'Aortic stenosis'.)

POSTOPERATIVE MANAGEMENT — The most important principles for postoperative management of patients with AS are volume management and management of arrhythmias. The observations below support these main treatment principles [47,48]:

●Maintenance of normal sinus rhythm with a moderate heart rate is important. Because the atrial "kick" may provide up to 40 percent of ventricular filling in patients with diastolic dysfunction or reduced LV compliance, rhythms other than sinus rhythm can have deleterious hemodynamic effects.

Atrial fibrillation (AF) with rapid ventricular response may be particularly poorly tolerated. If new-onset AF develops, reversible contributing factors (eg, electrolyte abnormalities or inadequate pain control) should be identified and addressed. Management of AF is dependent on symptoms, duration of AF, and need for rate or rhythm control, as discussed separately. Since stroke volume across the stenotic valve is relatively fixed, bradycardia (heart rate <40 beat per minute) should also be avoided. (See "Atrial fibrillation in patients undergoing noncardiac surgery", section on 'Postoperative atrial fibrillation'.)

●Intravascular volume and preload must be maintained. Reductions in preload, as may be precipitated by sedative or analgesics drugs, may be poorly tolerated because of impaired LV compliance. However, gradual volume overload from postoperative shifts in intravascular volume, as well as the gradual accumulation of ongoing intravenous fluids or blood products, will be poorly tolerated and result in HF. Accurate assessment of a patient's intake and output balance is essential.

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Cardiac valve disease" and "Society guideline links: Perioperative cardiovascular evaluation and management".)

SUMMARY AND RECOMMENDATIONS

●Risk of noncardiac surgery in patients with AS – Patients with significant aortic stenosis (AS) are at increased risk for cardiac complications, including intraoperative hypotension, myocardial infarction, ischemia, heart failure, arrhythmias, and death. (See 'Estimation of risk of noncardiac surgery' above.)

●Perioperative risk factors – Perioperative risk increases with AS severity; the presence of cardiac symptoms; the presence of concomitant cardiac risk factors, including ischemic heart disease, which is prevalent in patients with AS; and the risk level of the surgical procedure. As a result, assessment of an individual patient’s risk is best thought of as a global cardiac risk assessment. (See 'Risk factors' above.)

●Management for patients with asymptomatic severe AS – Observational data suggest that it is reasonable to perform moderate-risk elective noncardiac surgery with appropriate intraoperative and postoperative hemodynamic monitoring in patients with asymptomatic severe AS. (See 'Decisions before noncardiac surgery' above.)

●Management for patients with symptomatic severe AS – Patients with symptomatic severe AS should have elective noncardiac surgery delayed when possible. Patients with indications for aortic valve replacement should generally undergo surgical AVR (SAVR) or transcatheter aortic valve implantation (TAVI) prior to elective noncardiac surgery. (See 'Patients with indications for AVR' above.)

●Perioperative management of severe AS – Valve replacement is not feasible in some patients with indications for aortic valve surgery (eg, urgent or emergency life-saving surgery, multiple medical comorbidities, or patient refusal). Limited observational data suggest that perioperative risk can be managed with careful intraoperative monitoring in selected patients with severe, asymptomatic, or even symptomatic AS, particularly those with no significant coronary artery disease. (See 'Preoperative management' above.)

•Preoperative recognition of the severity of AS and any concomitant cardiac disease and communication with the anesthesiologist is essential. (See 'Preoperative assessment' above.)

•Postoperative management in patients with AS includes volume control and management of heart rate and rhythm. (See 'Postoperative management' above.)

ACKNOWLEDGMENT — The UpToDate editorial staff thank Anna M Booher, MD, and Prashant Vaishnava, MD, who contributed to earlier versions of this topic review.