Discussion:
Our patient demonstrates many of the classic characteristics of alkaptonuria, including kyphosis, corneal and pinnae pigmentation, as well as cardiac manifestations such as aortic valve stenosis and aortic dilation. The propensity of HGA deposits to manifest in joints, the aorta, and the base of the aortic valve suggests that increased pressure or turbulence leads to microvascular damage that primes the tissue for ochronosis, which subsequently leads to dystrophic calcification.3 This finding could potentially suggest that the severity of ochronosis in increased pressure environments, such as the joints, may act as an earlier indicator of the more disguised cardiovascular complications associated with alkaptonuria, and may also explain the presence of myocardial septal involvement in this patient with a history of hypertension.
Ather et al. reviewed 66 case reports of ochronotic cardiovascular disease.4 Until now, there has been only one other case report with a presentation similar to the this case: a patient with severe aortic stenosis and evidence of ochronosis of the aortic valve, coronary arteries, and the internal thoracic artery.5Another case series reported that 83% and 100% of patients over 60 years of age had aortic and intracardiac calcification respectively, without correlation to standard cardiac risk factors.3 This raises the question of whether the cardiovascular complications could potentially be predicted with increasing age in a patient with alkaptonuria, and whether these patients should undergo different cardiovascular screening than the rest of the population.
Previous to this case, the feasibility to successfully utilize ochronotic arterial conduits in a bypass setting and follow the patient outcomes has yet to be reported.6 Our patient’s post-operative care and 20-month follow-up, including TTE, revealed no deterioration to either the aortic valve or the overall ventricular function suggesting compromise of the arterial grafts. This demonstrates, for the first time, the safe utilization of ochronotic arteries in the setting of a CABG along with aortic valve replacement. Larger studies are needed to determine the long-term effects of alkaptonuria in patients with ochronotic heart disease who have undergone cardiac surgery.