A 78-year old female with severe aortic stenosis presents to the ICU following a transcatheter aortic valve replacement (TAVR). Preprocedural transthoracic echocardiography demonstrated severe aortic stenosis with left ventricular hypertrophy and an asymmetric septal bulge. Left ventricular wall thickness in the parasternal short axis view is 1.6 cm with a small cavity. Postoperatively, the patient develops sudden onset hypotension requiring vasopressor support; however, blood pressure continues to decrease despite escalating doses of norepinephrine.
The vital signs are:
Transthoracic echocardiography demonstrates an underfilled left ventricle with midventricular obstruction.
What is the most appropriate next step in management?
A. Discontinue norepinephrine and start phenylephrine infusionCorrect Answer: D
Hypotension following TAVR can be due to hypovolemia, acidosis, bleeding, myocardial infarction, acute heart failure, cardiac tamponade, aortic root injury, severe paravalvular leak, or dynamic intracavitary gradients. The abrupt release of the fixed aortic obstruction following TAVR can result in improvement in ventricular function. This increased inotropy can precipitate hypertrophic cardiomyopathy–like physiology in these severely hypertrophied ventricles. Patients with small left ventricular end diastolic diameters, asymmetric hypertrophy, high-valve gradients, and increased ejection fraction have an increased risk of dynamic intracavitary gradients. When these gradients are associated with acute hypotension and cardiovascular collapse, the term “suicide left ventricle” has been used. Treatment mirrors the treatment for the left ventricular outflow tract obstruction seen in hypertrophic cardiomyopathy. The most appropriate first choice in this patient’s management is correction of hypovolemia with fluid bolus administration. If hypotension persists despite increased preload, the catecholamine agents should be avoided and noncatecholamine vasopressors (phenylephrine, vasopressin) should be used. Beta blockers may be useful as well to decrease inotropy and allow ventricular filling, in the absence of hypotension.
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