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.