Mild to moderate aortic stenosis and coronary bypass surgery

Aortic stenosis (AS) is the most common valvular disease in adult cardiac surgery and its incidence continues to rise. Increasingly older patients are being referred for coronary artery bypass grafting (CABG) with mild to moderate AS. Concomitant aortic valve replacement (AVR) for patients with moderate or severe AS undergoing CABG is warranted regardless of symptoms. Concomitant AVR remains contentious in patients with less than moderate severity AS undergoing CABG.

We review the contemporary literature aiming to resolve this dilemma in clinical practice. The assessment of these patients is reviewed. Considerations include identifying the rapid progressors, and balancing the risks of concomitant valve surgery against the potential prognostic gains.

Pathophysiological links between degenerative calcific AS and coronary artery disease suggest that the disease is an active, progressive process with mutually shared risk factors. Statins, however, offer limited protection against AS, despite its established role in coronary artery disease. Age, atherosclerosis risk, valve morphology, motion, and hemodynamics identify the rapid progressors, whilst the patients' general comorbidities and life expectancy influence the risk-benefit profile of concomitant operations.

A precise echocardiographic quantification of the stenotic grade is mandatory before adopting any therapeutic strategy. Concomitant AVR for moderate AS is recommended if surgical risk is not prohibitive. Concomitant AVR for mild AS in 'rapid progressors' (i.e. moderate-severe valve calcification) may be considered, but patients should have reasonable life expectancy exceeding 5 years. Moderately restricted leaflet motions, gradient increase of > 10 mm Hg per year, and aortic jet velocity increase > 0.4 m/s per year further supports intervention. Comorbidities increasing atherosclerotic burden and renal dialysis accelerate AS progression and increase surgical risk. Procedural advances in interventional cardiology and minimally invasive cardiac surgery may further expand the options available for these patients.