The patient provided written permission for publication of the report. A 77-year-old man (height, 155 cm; weight, 55 kg) with a progressive thoracic aortic aneurysm and moderate degree of aortic valve stenosis was scheduled to undergo elective total aortic arch replacement and AVR. He had a history of hypertension, Stanford type-B aortic dissection, and chronic renal failure requiring hemodialysis. Preoperative laboratory investigations indicated chronic renal failure with an elevated serum creatinine level of 8.1 mg/dl and elevated serum urea nitrogen level of 42.7 mg/dl and increased ventricular load with an elevated serum brain natriuretic peptide of 280.5 pg/ml. A chest X-ray showed clear lung fields with a cardiothoracic ratio of 0.5. An electrocardiogram showed sinus rhythm at 55 bpm. A coronary angiogram showed mild non-obstructive coronary artery disease of the left anterior descending branch. Transthoracic echocardiography showed good left ventricular function with an ejection fraction of 66%, moderate aortic valve stenosis with a peak aortic jet velocity of 3.1 m/s, mild aortic insufficiency, and mild MR with a centrally directed jet and mitral annular calcification.
No premedication was given. General anesthesia was induced with 0.2 μg/kg/min remifentanil and 2 mg midazolam. After 50 mg rocuronium had been intravenously administered, the trachea was intubated and the patient’s lungs were mechanically ventilated. Anesthesia was maintained with 200 mg/h propofol, 0.2–0.3 μg/kg/min remifentanil, and intermittent bolus of fentanyl (total of 900 μg). An X7-2t probe (Philips Healthcare, WA, USA) was inserted, and an iE33 ultrasound device (Philips Healthcare, WA, USA) was used for intraoperative TEE monitoring. TEE examination before initiating cardiopulmonary bypass (CPB) demonstrated moderate aortic valve stenosis with aortic valve calcification and peak aortic jet velocity of 2.6 m/s, calcification extending beyond the aortic annulus to the mitral annulus, aortic valve annular diameter of 22.1 mm, mild aortic insufficiency with a vena contracta of 2.8 mm, mild MR with a centrally directed jet and a vena contracta of 2.3 mm resulting from restricted posterior mitral leaflet motion with compromised coaptation (Fig. 1a), and preserved left ventricular ejection fraction of 56% without regional wall motion abnormalities.
After instituting CPB, total aortic arch replacement was firstly performed under deep hypothermic circulatory arrest and selective cerebral perfusion. The native aortic valve was then excised and calcification of the aortic valve annulus was debrided. A 23-mm bioprosthetic valve (Carpentier-Edwards PERIMOUNT Magna Ease Aortic Heart Valve, Edwards Lifesciences, CA, USA) was subsequently sutured to the supra-annular position. Selection of the prosthetic valve size was based on fitting the sizer in the left ventricular outflow tract.
Following total aortic arch replacement and AVR, the patient was re-warmed and weaned off CPB on inotropic support of dopamine at 2.7 μg/kg/min and dobutamine at 2.7 μg/kg/min with ventricular pacing of 80 bpm. After separation from CPB, mean arterial blood pressure was maintained between 52 and 62 mmHg, and central venous pressure was maintained between 16 and 22 mmHg. TEE examination demonstrated severe MR (vena contracta, 8.6 mm) with restriction and distortion of the anterior mitral leaflet and incomplete valvular closure (Fig. 1b). The motion of the base of the anterior mitral leaflet was highly restricted compared with that of the control (Fig. 1a). The prosthetic aortic valve functioned normally with absence of perivalvular leakage. Myocardial hypokinesis, ventricular enlargement, and left ventricular outflow tract obstruction with a SAM of the mitral valve were not observed. There was no evidence of a damage of the mitral valve.
Displacement of the anterior mitral annulus towards the aorta by the prosthetic aortic valve that led to increased tethering forces to the anterior mitral leaflet was strongly suspected to be the cause of massive MR exacerbation based on the results of TEE interrogation. Re-AVR for treatment of the MR was therefore performed. Re-initiation of full CPB was followed by removal of the prosthetic aortic valve. Evidence of a suture at the aorto-mitral curtain near the anterior mitral leaflet was found. A new 21-mm bioprosthetic valve (St. Jude Medical Trifecta™ Valve, St. Jude Medical, MN, USA) was re-sutured to the supra-annular position, with suturing of the aortic annulus near the mitral valve being performed from outside of the aorta. Again, an attempt was made to discontinue CPB with inotropic support of dopamine at 4.5 μg/kg/min and dobutamine at 4.5 μg/kg/min under ventricular pacing of 80 bpm. The patient was separated from CPB without difficulty. After re-separation from CPB, mean arterial blood pressure was maintained between 60 and 69 mmHg, and central venous pressure was maintained between 10 and 14 mmHg. TEE examination of the mitral valve showed disappearance of the restriction and distortion of the anterior mitral leaflet and a dramatic reduction of the MR (vena contracta, 2.5 mm) (Fig 1c). Subsequently, the surgery was uneventfully completed without hemodynamic instability. The duration of the surgery was 11 h and 51 min.
Postoperatively, the patient was transferred to an intensive care unit. Extubation was conducted on postoperative day 3 after continuous hemodiafiltration. Postoperative transthoracic echocardiography after extubation revealed the absence of a prosthesis-patient mismatch and exacerbation of MR. The patient had an uneventful postoperative course without developing any complications and was discharged on postoperative day 37.
