Abstract
We encountered a case in which decreased cardiac afterload due to intra-aortic balloon pumping (IABP) caused left ventricular outflow tract obstruction (LVOTO), resulting in cardiogenic shock in a patient with hypertrophic obstructive cardiomyopathy (HOCM). The patient was a woman in her 60 with HOCM and angina, which were had been diagnosed before endometrial cancer surgery. An intra-aortic balloon pump was placed before surgery to maintain coronary artery blood flow, and increases in diastolic blood pressure were observed. However, she went into shock upon induction of anesthesia and required a large dose of vasopressor. The patient remained in shock after surgery and was admitted to the ICU while unresponsive and intubated. Transthoracic echocardiography showed LVOTO and mitral regurgitation, indicating the possibility that lowered cardiac afterload by IABP caused LVOTO. Discontinuation of IABP resulted in striking recovery from shock such that no vasopressor was required, and echocardiography findings improved. Although IABP offers a variety of benefits such as maintenance of coronary artery blood flow, we should keep in mind that decreased cardiac afterload due to IABP may cause LVOTO in patients with HOCM.
