Aortic Stenosis and Coronary Artery Disease: Causality Relationship
Neither aortic stenosis (AS) nor coronary artery disease (CAD) directly causes the other—they are distinct pathological processes that frequently coexist due to shared atherosclerotic risk factors and pathophysiological mechanisms. 1
Shared Pathophysiology, Not Causation
Both AS and CAD share common atherosclerotic processes and cardiovascular risk factors that explain their frequent coexistence, rather than one condition causing the other. 1
The American College of Cardiology explicitly notes that these conditions have overlapping pathophysiological mechanisms, which accounts for why approximately two-thirds of patients with AS have significant CAD (present in up to 65% of patients undergoing transcatheter aortic valve replacement). 1
Evaluation and modification of cardiac risk factors is important in patients with aortic valve disease to prevent concurrent CAD, emphasizing that prevention of CAD in AS patients focuses on shared risk factors rather than AS itself causing CAD. 1
Clinical Implications of Coexistence
When AS and CAD coexist, early risk reflects the effects of CAD, while late risk reflects diastolic left ventricular dysfunction expressed as ventricular hypertrophy and left atrial enlargement from AS. 2
Patients with AS and CAD have poorer hospital morbidity and long-term survival (43% vs. 59% at 10 years) compared to isolated AS, but this reflects additive disease burden rather than causation. 2
Patients with isolated AS and few comorbidities have the best outcome, those with CAD without myocardial damage have intermediate outcome, and those with CAD, myocardial damage, and advanced comorbidities have the worst outcome—demonstrating independent disease processes with cumulative effects. 2
Management Considerations Based on Coexistence
SAVR with CABG is appropriate for all patients with CAD and aortic stenosis when technically feasible, representing the standard of care for combined severe stenoses involving proximal arteries. 1
SAVR without coronary revascularization is rarely appropriate if there is significant CAD involving the LAD, 3 vessels, or left main coronary artery, highlighting the need to address both conditions independently. 1
In patients undergoing SAVR, the addition of CABG has been associated with improved long-term mortality, especially if CAD is complex, though it carries higher periprocedural risk. 3
Key Clinical Pitfall
The critical error is assuming one condition causes the other and therefore delaying treatment of either condition. Cardiovascular risk factors and comorbidities must be considered in managing patients with severe AS, and patients with severe AS and CAD risk factors should undergo early diagnostics and AVR+CABG before ischemic myocardial damage occurs. 2 This recommendation underscores that both conditions require independent assessment and timely intervention based on their own severity criteria, not on the presence of the other condition.