Cardiothoracic Surgery Expert Witness Opines on Fatal Aortic Valve Replacement

This case involves a seventy-seven-year-old female patient with severe aortic stenosis. The patient presented to her primary care physician with a 6 month history of worsening shortness of breath and was referred to a cardiologist. The cardiologist performed a transthoracic echocardiogram which revealed severe atrial stenosis with a valve area of 0.7 cm2. The cardiologist recommended that the valve be replaced. The patient underwent the aortic valve replacement surgery with a 21 mm Medtronic 3F tissue valve. Post-operatively the patient’s valve appeared to have a high gradient which was confirmed through cath lab evaluation. The decision was made to return the patient to the operating room for surgical revision of the valve replacement. She underwent removal of the first valve and an aortic root replacement with single vessel bypass grafting. The patient’s post-operative recovery was fraught with numerous complications. She suffered significant coagulopathy which was managed through anticoagulant therapy. The patient subsequently suffered hemorrhaging at the site of the surgical incision. Later, the patient developed heart failure which led to generalized edema. The patient was sent to the ICU with an open chest and returned for a mediastinal washout with temporary dressing closure. Hepatorenal failure and multi-organ system failure ensued shortly thereafter. The decision was made to withdraw life support after the patient developed massive acidosis which was thought to be caused by an abdominal event.

Question(s) For Expert Witness

1. Could this patient's complications have been avoided if the correct valve was initially placed?

Expert Witness Response E-004465

Assessment of the proper valve size is a matter of the cardiologist’s judgment when they do the pre-operative echocardiogram exam. He or she would then pass his findings on to the surgeon who will perform the valve replacement. Valve selection is a careful balance between what size valve a patient's anatomy will accept versus what size their physiology requires. It is by no means an exact science and it is not uncommon for an incorrectly fitting valve to be used. In this case, the treating surgeon went back and had to replace the aortic root to replace the valve likely meaning the initial valve orifice was too small. This is not an uncommon problem in the elderly, in particular, implanting either stentless valves or tissue valves in general in an elderly and small female patients, as was the case here. It is difficult to predict the valve size that would be adequate without enlarging the aortic orifice. The treating surgeon did the right thing in re-operating on the patient once it was verified that the first valve was not performing well. Due to the patient’s advanced age, it is likely that she may have had several co-morbidities such as borderline renal and pulmonary functions which would further complicate her post-operative recovery.