Diastolic Dysfunction, Cardiovascular Aging, and the Anesthesiologist

A 74-year-old female presented to the preoperative assessment clinic (PAC) prior to elective, right shoulder, arthroplasty. Her past medical history was significant for hypertension, osteoarthritis, and mild chronic obstructive pulmonary disease. She denied any cardiovascular symptoms with the exception of increasing exertional shortness of breath while walking her dog up the hill to her house. She attributed this change in exercise tolerance to “getting older and out of shape.” The patient quit smoking 25 years ago and regularly takes her antihypertensive regimen of hydrochlorothiazide and lisinopril. In the PAC her vital signs were the following; blood pressure 158/64 mmHg, pulse 78 beats/min, and room air oxygen saturation 100%. Auscultation of her chest revealed clear lung sounds and a regular cardiac rate and rhythm with a mid-grade (3 to 4/6) systolic ejection murmur radiating to her carotid arteries. A 12-lead electrocardiogram showed normal sinus rhythm and nonspecific S-T wave changes. A transthoracic echocardiogram was obtained which revealed a normal ejection fraction of 65%, impaired left ventricular relaxation, moderate concentric left ventricular hypertrophy, moderate left atrial enlargement, and severe aortic valve stenosis (AVA = 0.9 cm2; peak gradient 60 mmHg) with mild aortic regurgitation. The patient was referred to cardiology and subsequently underwent a coronary and right heart catheterization which showed nonobstructive coronary disease, a peak left ventricular pressure gradient of 75 mmHg and an end diastolic pressure of 22 mmHg. The patient was scheduled for aortic valve replacement surgery with cardiopulmonary bypass (CPB). Intraoperative anesthetic and surgical care of the patient were uneventful; she was managed with an isoflurane and fentanyl-based anesthetic, and muscle relaxation was achieved with cisatracurium. A 23-mm stentless, bioprosthetic aortic valve was inserted and the patient was weaned from CPB without inotropes. Following closure of her sternum, transient episodes of hypotension (80/60 mmHg) occurred with concomitant echocardiographic evidence of left ventricular (LV) underfilling that responded to volume loading with colloid. The patient was hemodynamically stable upon transfer to the intensive care unit (ICU), sedated with dexmedetomidine, and on a low dose infusion of phenylephrine. During the first 6 hours in the ICU, the patient’s cardiac index dipped below 2.0 which corresponded to her relatively low cardiac filling pressure (LVEDP <18 mmHg) and labile blood pressure. Due to the minimal chest tube drainage and hemodynamic lability, a bedside TEE was performed which was negative for evidence of cardiac tamponade, but it did confirm a relative hypovolemia. The patient responded well to volume resuscitation and her hemodynamics stabilized at an LVEDP 24 mmHg. She was subsequently weaned from the ventilator on the morning of POD 1 and remained hemodynamically stable and cognitively intact before transfer to a floor bed on postoperative day two. On POD 3 her family remarked that she was “not herself” and somewhat disoriented. Her oxygen requirements had increased over the preceding 24 hours, and her physical exam and chest x-ray were consistent with pulmonary edema. An electrocardiogram revealed atrial fibrillation. Her blood pressure was 95/60 mmHg. The patient was transferred to the ICU for closer observation, and for re-intubation after low oxygen saturation did not respond to face shield oxygen or Bi-PAP. Her cardiac rhythm was medically converted with amiodarone, and she was carefully diuresed with furosemide prior to extubation a day later. She progressed slowly and was discharged to a rehabilitation facility on POD 8 prior to returning to her home.