Management of patients with mild aortic stenosis undergoing coronary artery bypass grafting

Management of Less-Than-Severe Aortic Stenosis During Coronary Bypass: A Systematic Review and Meta-Analysis

OBJECTIVE

The management of concomitant mild-to-moderate aortic stenosis (AS) at the time of coronary artery bypass graft (CABG) is controversial. Here we perform a systematic review and meta-analysis of CABG and aortic valve replacement (AVR) versus CABG alone in patients with mild-moderate AS.

METHODS

We searched MEDLINE and EMBASE databases until July 2018 for studies comparing CABG & AVR versus CABG in patients with mild-moderate AS undergoing coronary bypass. Data were extracted by 2 independent investigators. The main outcomes were operative mortality, long-term survival, and reintervention for AS.

RESULTS

There were 6 unmatched retrospective observational studies with 1,172 patients (median follow-up 4.7 [interquartile range: 4.3 to 5.3] years). Patients undergoing CABG & AVR had less severe coronary artery disease. There were no differences in operative mortality (relative risk [RR]: 1.07; 95% CI, 0.59 to 1.94; P = 0.8). CABG & AVR was associated with greater incidence of stroke, bleeding, renal failure, and mediastinitis. At median follow-up of 5 years, there was no difference in long-term mortality (incidence rate ratio [IRR]:1.44; 95% CI, 0.83 to 2.51; P = 0.19), but CABG & AVR was associated with 73% lower risk of reoperation for AS (n = 13/485 versus n = 71/702; IRR: 0.27; 95% CI, 0.14 to 0.51; P < 0.001).

CONCLUSIONS

In patients undergoing CABG with mild-moderate AS, combining AVR with CABG was associated with no difference in operative mortality but with increased risk of stroke, bleeding, renal failure, and mediastinitis. Long-term mortality was not different, but a risk of reoperation for AS at 5 years was 73% lower. Given the increasingly wide availability and safety of transcatheter aortic valve replacement (TAVR), one may consider a conservative approach toward concomitant mild-moderate AS.

Moderate aortic stenosis in coronary artery bypass grafting patients more than 70 years of age: to replace or not to replace?

BACKGROUND

Moderate aortic stenosis in coronary artery bypass graft surgery (CABG) patients more than 70 years old is not unusual. The risk-benefit of performing a concomitant aortic valve replacement (AVR) is often difficult to assess. To stratify the risk-benefit ratio, we reviewed outcomes of CABG patients more than 70 years old with preoperative moderate aortic stenosis (valve area 1.0 to 1.6 cm(2) or indexed valve area 0.6 to 1.0 cm(2)/m(2)).

METHODS

Among 263 CABG patients more than 70 years old with moderate aortic stenosis, 167 patients underwent only CABG and 96 had CABG+AVR.

RESULTS

Cross-clamp time (p < 0.0001) and perioperative transient ischemic attack-cerebrovascular accident (p < 0.04) were significantly higher in the CABG+AVR group. In-hospital mortality was comparable among groups (CABG 6.0% versus CABG+AVR 4.2%; p = 0.8). At a mean follow-up of 4.5 ± 3.0 years, 5-year survival (CABG 64.2% ± 4.3% versus CABG+AVR 62.3% ± 5.5%) and freedom from AVR (CABG 97.8% ± 1.2% versus CABG+AVR 98.9% ± 1.1%; p = 0.13) were comparable among both groups. Among patients treated with CABG alone, receiver operating characteristic curve analysis identified 26 mm Hg and 15 mm Hg as maximum and mean aortic valve gradients, respectively, for increased risk of reoperation for late AVR. Multivariate analyses for predictors of operative mortality were preoperative renal failure (odds ratio [OR] 7.64, p < 0.001) and intubation more than 48 hours (OR 11.10, p < 0.0002); for late death, ejection fraction less than 40% (OR 3.35, p < 0.02), New York Heart Association functional class III or IV (OR 2.37, p < 0.002), chronic obstructive pulmonary disease (OR 2.26, p < 0.02), and renal failure (OR 3.03, p < 0.003); for perioperative transient ischemic attack-cerebrovascular accident, cross-clamp time (OR 1.02, p < 0.02) and Parsonnet score (OR 1.09, p < 0.05).

CONCLUSIONS

For CABG patients more than 70 years old with minimal comorbidities especially in the presence of aortic gradients of 26/15 mm Hg or greater, concomitant AVR for moderate aortic stenosis should be performed during CABG and may be performed with minimal additional operative risk. Patients with significant comorbidities should be managed with CABG alone, owing to an increased perioperative risk, poor midterm survival, and minimal risk of AVR at 5 years.

Cusp shaving for concomitant mild to moderate rheumatic aortic insufficiency

BACKGROUND

The aim of this study was to assess the early and mid-term results of patients who underwent cardiac operations due to cardiac pathologies other than aortic valve (AV) disease, but also had mild-to-moderate aortic valve insufficiency that was repaired during the same session.

METHODS

A total of 43 patients who underwent AV repair for mild-to-moderate aortic insufficiency between January 2003 and February 2009, in addition to the procedure performed for their main pathology necessitating the surgical intervention, were included in the present study. Cardiac function was evaluated, before and after the operation.

RESULTS

Hospital mortality rate was 4.6% (two patients). After the operations, significant improvements were observed in aortic insufficiency (0.57 +/- 0.50 vs. 2.86 +/- 0.48, p = 0.001), New York Heart Association class (1.08 +/- 0.28 vs. 3.03 +/- 0.44, p = 0.001), and left atrial diameter (47.37 +/- 9.28 vs. 42.35 +/- 7.02; p = 0.001). However, left ventricular end diastolic and end-systolic diameters remained unchanged. Two patients were re-operated for AV disease during the follow-up period; thus, at five years, the rate of freedom from re-operation due to AV pathology was 90.7 +/- 6.3%.

CONCLUSIONS

Cusp shaving is a feasible option that can be performed with low risk for concomitant aortic insufficiency.

Aortic valve replacement in patients with mild or moderate aortic stenosis and coronary bypass surgery

PURPOSE

To assess whether there is survival benefit for patients with mild or moderate aortic stenosis if they undergo aortic valve replacement at the time of coronary artery bypass surgery.

METHODS

From 1985 to 1995 we evaluated all patients at our institution who underwent coronary artery bypass surgery and who had the echocardiographic diagnosis of mild (mean gradient <0 mm Hg and/or valve area >1.5 cm(2)) or moderate (mean gradient > or =30 and < or =40 mm Hg and/or valve area >1.0 < or =1.5 cm(2)) aortic stenosis. Using propensity analysis, survival was compared between 129 patients who underwent coronary artery bypass surgery alone and 78 patients who underwent concomitant coronary artery bypass surgery and aortic valve replacement.

RESULTS

Perioperative mortality was similar among patients who underwent coronary artery bypass surgery alone compared with patients who underwent concomitant coronary artery bypass surgery and aortic valve replacement. By Kaplan-Meier analysis, 1-year and 8-year survival were better at 90% and 55% for patients who underwent concomitant coronary artery bypass surgery and aortic valve replacement compared with 85% and 39% for patients who underwent coronary artery bypass surgery alone (P <0.001). This benefit was limited to patients with moderate aortic stenosis (propensity-adjusted relative risk = 0.43; 95% confidence interval: 0.20 to 0.96; P = 0.04).

CONCLUSION

Concomitant aortic valve replacement at the time of coronary artery bypass surgery for mild or moderate aortic stenosis appears to convey a survival advantage for patients with moderate aortic stenosis but not for those with mild aortic stenosis.

[Mild aortic stenosis and coronary bypass surgery]

The presence of mild to moderate aortic stenosis in a patients scheduled for coronary bypass surgery poses difficult problems with respect to the optimal therapeutic strategy. The first step is obviously to obtain a precise quantification of the degree of stenosis. Whenever possible, confrontation with previous echo examinations will provide an idea of the speed with which aortic stenosis progresses. The cardiologist, together with the cardiac surgeon, will have to carefully balance the operative risk and the risk of a second intervention. The patient's age will be central in the discussion, as it is a major determinant of life expectancy after the initial intervention.

When is concomitant aortic valve replacement indicated in patients with mild to moderate stenosis undergoing coronary revascularization?

Mild to moderate aortic stenosis is a common finding in patients presenting for coronary artery bypass grafting (CABG), and its management is controversial. However, review of available data suggests a surgical strategy for these patients. Recent data demonstrate that 1) progression of aortic stenosis is more rapid in those with leaflet calcification; 2) the addition of aortic valve replacement to CABG in patients with mild to moderate stenosis does not increase hospital mortality when compared with bypass surgery alone; 3) hospital mortality for aortic valve replacement after previous bypass surgery has declined in recent years; 4) aortic valve replacement places the patient at risk for prosthesis-related complications; 5) the limited 10-year survival (competing risk of death) leaves only a minority of individuals with mild aortic stenosis alive and eligible for aortic valve replacement 10 years after bypass surgery; and 6) combined aortic valve replacement and CABG confers a survival benefit in those with moderate aortic stenosis but not in those with mild aortic stenosis. Therefore, in the coronary artery bypass patient with moderate aortic stenosis, leaflet calcification, and life expectancy greater than 5 years, concomitant aortic valve replacement is advised. In contrast, aortic valve replacement is rarely indicated in those with mild aortic stenosis.

Aortic valve replacement in patients with previous cardiac surgery

BACKGROUND

Whether minimally diseased aortic valves should be replaced during other necessary cardiac operations remains controversial. Part of the decision-making process in that issue revolves around the risks of subsequent aortic valve replacement. This study evaluated the results of aortic valve replacement in patients following prior cardiac surgery.

METHODS

From February, 1984 through December, 2001 first-time aortic valve replacement was performed in 132 consecutive patients who had previous cardiac surgery utilizing cardiopulmonary bypass. Of those patients 89 (67%) had aortic valve replacement at a mean of 8.3 years after prior coronary artery bypass grafting, and 43 (33%) had aortic valve replacement at a mean of 13.0 years after previous procedures other than myocardial revascularization. Hospital records of all patients were retrospectively reviewed.

RESULTS

Early complications included operative mortality in six (6.7%) of the patients with prior coronary grafting and no mortality in the group with other prior operations. Patients having prior coronary grafting had more nonfatal complications than those with other previous procedures.

CONCLUSIONS

Aortic valve replacement in patients following previous cardiac surgery can be accomplished with acceptable mortality and morbidity. Routine replacement of aortic valves that are minimally diseased during coronary artery bypass grafting may not be warranted.

Should coronary artery bypass graft surgery patients with mild or moderate aortic stenosis undergo concomitant aortic valve replacement?

OBJECTIVES

This study utilizes Markov decision analysis to assess the relative benefits of prophylactic aortic valve replacement (AVR) at the time of coronary artery bypass graft surgery (CABG). Multiple sensitivity analyses were also performed to determine the variables that most profoundly affect outcome.

BACKGROUND

The decision to perform CABG or concomitant CABG and AVR (CABG/AVR) in asymptomatic patients who need CABG surgery but have mild to moderate aortic stenosis (AS) is not clear-cut.

METHODS

We performed Markov decision analysis comparing long-term, quality-adjusted life outcomes of patients with mild to moderate AS undergoing CABG versus CABG/AVR. Age-specific morbidity and mortality risks with CABG, CABG/AVR, and AVR after a prior CABG were based on the Society of Thoracic Surgeons national database (n = 1,344,100). Probabilities of progression to symptomatic AS, valve-related morbidity, and age-adjusted mortality rates were obtained from available published reports.

RESULTS

For average AS progression, the decision to replace the aortic valve at the time of elective CABG should be based on patient age and severity of AS measured by echocardiography. For patients under age 70 years, an AVR for mild AS is preferred if the peak valve gradient is >25 to 30 mm Hg. For older patients, the threshold increases by 1 to 2 mm Hg/year, so that an 85-year-old patient undergoing CABG should have AVR only if the gradient exceeds 50 mm Hg. The AS progression rate also influences outcomes. With slow progression (<3 mm Hg/year), CABG is favored for all patients with AS gradients <50 mm Hg; with rapid progression (>10 mm Hg/year), CABG/AVR is favored except for patients >80 years old with a valve gradient <25 mm Hg.

CONCLUSIONS

This study provides a decision aid for treating patients with mild to moderate AS requiring CABG surgery. Predictors of AS progression in individual patients need to be better defined.

Management of Mild Aortic Stenosis During Coronary Artery Bypass Surgery:

BACKGROUND

"Prophylactic" aortic valve replacement (AVR) in patients with asymptomatic, mild-to-moderate aortic stenosis (AS) at the time of CABG is controversial. In 1994, we reported our initial experience involving 44 patients and have now updated our series in an attempt to further evaluate outcomes.

METHODS

Between January 1992 and July 2001, 100 consecutive patients underwent reoperative AVR following previous CABG. Forty patients had their initial surgery at the Brigham & Women's Hospital (BWH) and 60 patients had their coronary surgery elsewhere. None of the 40 BWH patients had a mean valve gradient greater than 25 mmHg at the time of CABG.

RESULTS

The mean time interval from CABG to AVR for the entire group was 9.0 years (range: 1.4-21 years). Overall operative mortality (OM) was 7% including 5 deaths (10.2%) among 49 patients requiring additional CABG at the time of AVR and 2 deaths (3.9%) among 51 patients without additional coronary artery intervention. This OM rate was a notable decrease from our earlier report of 18.2% (P = 0.07). Furthermore, operative mortality decreased progressively from 15.4% in 1992-1993 to 0% in 2000-2001 (P = NS).

CONCLUSION

The OM of reoperative AVR following CABG has fallen in recent years. Given the relevance of newer techniques and approaches, it may be reasonable to adopt an expectant management approach in patients with asymptomatic mild-to-moderate AS (i.e., mean systolic gradient less than 25 mmHg) at the time of CABG.

Aortic valve replacement under deep hypothermic circulatory arrest

BACKGROUND

Aortic valve replacement (AVR) in the presence of a calcified aorta or patent grafts may preclude clamping of the ascending aorta. We employed deep hypothermic circulatory arrest in order to circumvent this problem.

METHODS

Between January 1993 and December 2000, 415 patients underwent AVR in our department. Eight of these were operated using deep hypothermic circulatory arrest. There were 5 males, and mean age was 72 years (range 56-81). Indications for using circulatory arrest were reoperation with patent grafts and/or severe calcification of the ascending aorta. In six patients, cardiopulmonary bypass was achieved via femoro-femoral bypass, and in two via aortic-right atrial cannulation. Retrograde cerebral perfusion was employed in five. Mean bypass time was 155 minutes (range 122-187), and mean circulatory arrest time was 38 minutes (range 31-49).

RESULTS

There was no operative mortality, and no patient suffered any neurologic sequelae. Echocardiography showed all valves to be functioning well.

CONCLUSIONS

AVR under deep hypothermic circulatory arrest can be accomplished with an acceptable degree of safety. It should be considered as an alternative in patients in whom aortic clamping is prohibitive, and might otherwise be considered inoperable. The ability to connect the patient to bypass and the presence of a "window" to allow aortotomy are prerequisites for employing this method.

Aortoscopy: a less invasive intraoperative method to assess the aortic valve

Surgical management of mild aortic stenosis coexisting with severe coronary artery disease remains controversial. Direct examination of the aortic root under these circumstances may be decisive. At present, intraoperative assessment of the aortic valve requires an aortic incision which, in itself, may increase the risk of intraoperative complications, particularly when this portion of the aorta is needed to construct proximal graft anastomoses. We present a simple aortoscopic method for direct intraoperative assessment of the aortic valve while performing coronary bypass grafting that obviates the need for aortic incisions.

[Multiple-valve disease]

After more than 40 years of heart valve surgery, the indication for double valve procedures still represents a problem in the presence of an obviously leading single valve disease. If the isolated valves do not already represent a clear indication for surgery then this situation is the best example for a good deal of thought in cardiac surgery and discussion with competent cardiologists.

Current status and future directions of minimally invasive cardiac surgery

The impetus to reduce the trauma of surgery witnessed over the past decade in all fields of surgery has recently extended into the cardiac surgical arena; however, unlike other specialties, the invasiveness of cardiac surgery can be reduced by limiting the size of incisions and by avoiding cardiopulmonary bypass. This article reviews the rationale, clinical experience, and outcomes of the minimally invasive approaches to cardiac surgery that have evolved over the past 2 years and glimpses into the future of this rapidly evolving field.