ANG-First Trial (Angiotensin II as First-Line Vasopressor Therapy in Cardiac Surgery)

Inclusion Criteria:

* Adult patients ≥ 18 years of age undergoing cardiac surgery requiring CPB
* Patients must have clinical features of vasodilation as determined by a MAP \< 65 mmHg that is non-transient in the opinion of the treating physician
* Patients must be adequately volume resuscitated in the opinion of the treating physician
* Systemic Vascular Resistance index (SVRi) \< 1970 dynes·sec/cm⁵/m² to support the clinical diagnosis of vasodilation; if no pulmonary artery catheter is in place, vasodilatory hypotension diagnosis according to the judgement of the critical care team
* Biventricular systolic function is at or greater than pre-cardiopulmonary bypass baseline as demonstrated by echocardiographic evaluation, or the patient is concomitantly treated with

Exclusion Criteria:

* Bleeding as primary etiology of hypotension, as determined by \> 4 units RBC transfusion in 24 hours.
* Patients on ECMO
* Patients with active endocarditis
* Patients already on renal replacement therapy or creatinine of \> 4 mg/dl within 2 weeks of surgery
* Patients with contraindications to Angiotensin II including women who are pregnant or breastfeeding or have active coronary ischemia, mesenteric ischemia, limb ischemia, or high potassium (\> 5.5 meq/L) while receiving Angiotensin II