Background: Patients with bicuspid aortic valve (BAV) experience valvular complications at an accelerated rate. While BAV is generally regarded as a benign anatomical variant, recent histological and cardiac imaging studies suggest significant hemodynamic instability in even asymptomatic BAV patients.

Case Presentation: A previously healthy 59-year-old man was referred for new-onset difficult-to-control hypertension. Echocardiography revealed a mildly calcified but well-functioning bicuspid aortic valve (BAV) and there were signs of chronically elevated left-sided heart pressures, though the patient denied any symptoms and exercise stress testing was normal. Over the next 2 years he failed multiple antihypertensive drug regimens despite proper compliance. He eventually presented to the hospital with profound hypotension and was found to have infective endocarditis complicated by a perivalvular abscess requiring mechanical aortic valve replacement (AVR). Prior to AVR, he struggled to maintain blood pressure on a 3-drug regimen and his response to atenolol reflected that of elderly patients with isolated systolic hypertension from age-related aortic stiffening. Following AVR, a dramatic improvement was observed in the patient’s blood pressure, now responsive to nebivolol monotherapy at half the previous dose, and he has remained stable at 1, 3, and 6-month follow up.

Discussion: Hemodynamic instability and ascending aorta (AAo) stiffness are intimately associated with BAV, regardless of age, valvular function, aortic diameter, or atherosclerotic plaque burden. While the exact etiology of AAo stiffening in BAV patients has not been confirmed, recent histological studies suggest a similar–but accelerated–mechanical stress-induced phenotypic shift in vascular smooth muscle cells (VSMCs) which has previously been implicated in thoracic aortic disease and age-related aortic stiffening. Reactive deposition of extracellular matrix initially serves to dampen mechanical stress and maintain homeostasis; however this ultimately increases pulse wave velocity (PWV) and central systolic pressure, perpetuating a feedforward loop of maladaptive stiffening and increased myocardial demand. Supporting these findings are recent strain imaging studies revealing subclinical diastolic dysfunction associated with aortic stiffness in asymptomatic BAV patients. Consensus guidelines for BAV surveillance currently address aortic aneurysm detection but fail to address its likely precursor–loss of AAo distensibility due to the intrinsic hemodynamic abnormalities of BAVs. Strain imaging offers immense value for this application but is not yet widely available in clinical practice. In the meantime, assessment of PWV on doppler echocardiography may be a valuable surrogate for aortic stiffness in BAV patients.