A 90‐year‐old woman with a medical history significant for upper‐extremity DVT provoked by a central venous catheter and ileostomy history of sepsis secondary to C. difficile colitis was admitted to the hospital for revision of left hip arthroplasty. Previous arthroplasty was complicated by acetabular protrusion, and hence, she was scheduled for the revision. Preoperatively patient denied chest pain or shortness of breath. However, she was unable to achieve 4 METs due to hip pain. She had no history for CAD, stroke, DMII, CKD, or CHF. Patient had had numerous other surgeries including bilateral total knee replacement, hysterectomy, appendectomy, and cholecystectomy without any cardiac complications. Preoperative examination was unremarkable with normal BP and no murmurs, gallops, or rubs on cardiac auscultation. Her only medications were omeprazole and vitamin B12. Patient was deemed average risk for the intermediate‐risk procedure. Intraoperatively patient was given a spinal anesthetic, which was well tolerated, but because of the procedure length, it was converted to an LMA. Unexpected hypotension during the surgery required 3.2 L of crystalloid, 500 cc of albumin, and 2 U of pRBCs. Because of increased pressor support, she was brought to the SICU after the surgery. On initial postoperative evaluation, patient was alert, comfortable, without any complaints. Vital signs revealed blood pressure 90/60, normal heart rate on phenylephrine drip. There was new‐onset grade 4/6 systolic murmur at the apical area radiating to the axilla. Hemoglobin was 7 mg/dL compared with preoperative level of 12 mg/dL; EKG, renal function, and troponins were negative. Echocardiogram revealed dynamic left ventricular outflow tract (LVOT) obstruction with peak velocity of 4.2 L/m/s and moderate to severe mitral regurgitation due to systolic anterior motion (SAM) of the anterior MV leaflet. Follow‐up echocardiogram 3 days later revealed resolution of outflow obstruction and asymmetrical septal hypertrophy.
Although usually associated with structural abnormalities such as HCOM or mitral valve repair, SAM can occur without cardiac pathology in patients undergoing general anesthesia. Hypovolemia due to blood loss or vasodilator effect of anesthetic agents can result in LV underfilling. This reduces the LVOT size, resulting in a hyperdynamic LV. Underfilling of the LV also changes the geometry of the ventricle to move the papillary muscles relatively anterior and inward. The hyperdynamic state raises outflow tract velocity, increasing drag forces on the MV, resulting in LVOT obstruction. This should be managed by volume resuscitation, as these patients are preload dependent, peripheral vasoconstriction, and beta‐adrenoceptor blockade.
For hospitalists, hypotension is a common problem with a broad differential diagnosis. SAM can cause severe postoperative hypotension due to left ventricular outflow tract obstruction and/or mitral regurgitation. It is associated with up to a 20% risk of sudden death.
To cite this abstract:Hartog N, Kamath A. Ninety‐Year‐Old Evaluated by Medical Consult for Postoperative Hypotension. Abstract published at Hospital Medicine 2013, May 16-19, National Harbor, Md. Abstract 302. Journal of Hospital Medicine. 2013; 8 (suppl 2). https://www.shmabstracts.com/abstract/ninetyyearold-evaluated-by-medical-consult-for-postoperative-hypotension/. Accessed August 17, 2019.