Comment
Residual subaortic obstruction is a common cause of persistent symptoms
following septal reduction therapy (SRT) and may be more common
following ASA compared to surgical myectomy. As illustrated in our
patient, however, other cardiac problems may contribute to poor
functional outcome post procedure. Patients with HCM and midventricular
obstruction have effort-related symptoms that are often
indistinguishable from those caused by subaortic obstruction, and it is
important to identify this before SRT. Combined subaortic and
midventricular obstruction is difficult to eliminate with ASA and may
require injection in multiple septal perforating arteries with excess
volume of alcohol. For surgical myectomy in patients with both
subaortic and midventricular obstruction, we prefer transapical approach
for mid ventricular septal resection combined with transaortic exposure
for the subaortic
myectomy.[3]
Constrictive pericarditis (CP) causes impaired diastolic ventricular
filling, [4] and it may
be difficult to distinguish the symptoms of dyspnea and fatigue between
CP and HCM, There were no antecedent events in our patient that might
have caused constriction and raised suspicion regarding the diagnosis.
Detailed hemodynamic assessment did suggest constrictive pericarditis
and this important finding supported proceeding with operation.
[5]
Extensive calcification of the ascending aorta, ”porcelain aorta,” is
prevalent in the elderly and may reflect increased arterial
stiffness.[6]. Of more
importance to the surgeon is the potential difficulty in aortic clamping
and securing hemostasis following simple aortotomy when extensive plaque
is present in the ascending and sinus portions of the aorta. In the
present case, excision of the ascending aorta and graft replacement
appeared to be the safest method for exposing the subaortic area and for
ensuring hemostasis.