Upon arrival, the cardiologist is still concerned about the
diagnosis. He decides to review the inflight recordings and TTE together
with the other available clues. He returns to the patient, listens for
the diastolic murmur reported at initial examination, notes that the
pain was non-stress induced and considers the dilated aortic root. He
tries to think of an alternative diagnosis which could integrate all of
these clues, thinking through different possible aortic conditions, and
realizes that a dissecting thoracic aortic aneurysm11could explain all of these symptoms: the dilated root is part of the
aneurysm and a small flap in the beginning tear could produce the
murmur. The patient is taken directly to surgery where ascending (type
A) aortic dissection is repaired. He was discharged home after one
week.
Commentary: Given the state of the patient, the physicians are
forced to act even though the evidence remains puzzling. The
cardiologist does not consider the diagnosis of cardiac ischemia
particularly likely due to the lack of expected observations (minimal
pain relief from morphine, non-diagnostic cardiac enzymes and ECG). But
he currently lacks a plausible alternative.
He chooses a strategy for generating an alternative diagnosis, deciding
to review all of the available clues, including ones that initially were
not considered salient (the soft murmur), to guide his search for
alternative diagnoses. Like the emergency room clinician, given the
negative result for embolism, he considers the most serious remaining
possibility an acute aortic syndrome, also suggested by the dilated
aortic root. Relying on his background knowledge, he directs his
attention towards possible aortic syndromes and quickly thinks of a
possibility—a dissecting aneurysm—capable of explaining the
symptoms. Once he has in mind this newly generated hypothesis he
immediately recognises that it would be able to explain all of the
otherwise puzzling evidence. On this basis, he judges it more likely
than ACS and decides to adopt it as a basis for the surgical
intervention. While one cannot guarantee such judgements to always be
correct, given the urgency of the situation, it was in this case a
reasonable and, fortunately, successful approach.