Intravenous angiotensin II as an add-on to standard of care vasopressors in patients with refractory shock on mechanical circulatory support: a single centre retrospective case series
Authors: Sipus D , Momcilovic M , Percin L , Fabijanovic D , Pasara V , Jakus N , Planinc I , Pasalic M , Jurin H , Samardzic J , Skoric B , Cikes M , Milicic D , Lovric D 
Published: May 2024

Abstract

Funding Acknowledgements
None.

Background
Refractory shock is life-threatening condition characterized by hypotension with mean arterial pressure (MAP) less than 65 mmHg and end-organ dysfunction, despite volume resuscitation and high doses of vasopressors. Mortality rates in refractory shock exceeds 90%. Angiotensin II (Ang II) is a non-catecholamine vasopressor that targets the renin-angiotensin-aldosterone system by agonism of the angiotensin type 1 receptors. Ang II has been studied in settings of vasodilatory shock, however there is paucity of data regarding the usage of Ang II in patients with preexisting heart failure or in patients requiring mechanical circulatory support (MCS), either short term such as venoarterial extracorporeal membrane oxygenation (VA-ECMO) or long term such as left ventricular assist device (LVAD) (1,2).

Purpose
This report is aimed to analyse baseline characteristics of patients who have received Ang II from the moment it became available in our institution (January 2023).

Methods
Five patients were included in this retrospective analyses. Demographic, clinical and laboratory parameters as well as hourly changes of vasopressors doses, MAP, lactates, and diuresis were collected and analysed.

Results
Median age of 5 included patients, 4 of whom were male, was 53 years old (range 18-57). The most common comorbidities were chronic kidney disease (n=3), diabetes mellitus (n=3) and arterial hypertension (n=3), treated with valsartan as chronic therapy. All patients presented with severe shock. 4 patients were on VA-ECMO support, 1 had additionally implanted Impella for left ventricular unloading and 2 had implanted LVAD. All patients had severely reduced left ventricular ejection fraction (median 15%, range 10-25%). In 4 cases vasopressors were initiated due to sepsis and in 1 case during cardiopulmonary resuscitation. Median values prior to administration of Ang II were as following: MAP 51 mmHg (range 41-56 mmHg), lactates 6.7 mmol/L (range 2.4-10.7 mmol/L) and Sequential Organ Failure Assessment (SOFA) score 9 (range 5-11). Four hours following administration of Ang II median MAP was 61 mmHg (range 54-77 mmHg). Patient who ultimately survived had better response to Ang II, with median rise of MAP of 22 mmHg (range 12-22 mmHg). In contrast, patients who ultimately died didn’t respond to Ang II, with rise of MAP of only 2.5 mmHg. Median duration of Ang II administration was 52 h (range 20-96 h). 60% of patients are alive up to the present day. Complete patient data are shown in Table 1. Hourly changes of vasopressor doses and MAP are shown in Figure 1.

Conclusion
Ang II is an effective vasopressor with rapid effect. This case series suggests that it may be considered as salvage treatment option in patients on MCS with refractory shock. Patients who responded to Ang II had better survival, similar to previous findings. Therefore, Ang II should be considered in earlier phases of shock when maximum doses of vasopressors have not yet been reached.