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Angiotensin in ECMO patients with refractory shock
Critical Care volume 22, Article number: 288 (2018)
- The Letter to this article has been published in Critical Care 2019 23:144
Refractory vasodilation and catecholamine resistance are common in septic shock. Changes in receptor signaling, excessive production of nitric oxide, and absolute or relative deficiencies of vasoactive hormones, including cortisol, vasopressin, and angiotensin II, play a role. Angiotensin II (Ang II) was previously available as a vasopressor but removed from the market in the 1990s. Interest was re-ignited following the Angiotensin II for the Treatment of Vasodilatory Shock (ATHOS-3) study, a randomized controlled trial in patients with refractory shock which confirmed that Ang II was effective at maintaining mean arterial pressure and reducing norepinephrine requirements without an increase in side effects . Patients receiving renal replacement therapy also had improved survival and faster recovery of renal function . Recent literature noted the potential role of Ang II in other types of shock .
The major physiological effects of Ang II relate to maintenance of hemodynamic stability and fluid and electrolyte regulation (Table 1). Angiotensinogen, the precursor of angiotensin, is produced primarily by the liver and released into the systemic circulation where it is converted to angiotensin I (Ang I). Ang I is cleaved into Ang II, predominantly by angiotensin converting enzyme (ACE), an endothelium bound protein that is primarily expressed in the pulmonary and renal capillary beds. In patients with acute respiratory distress syndrome, ACE insufficiency has been reported . In veno-arterial ECMO, a proportion of blood bypasses the lungs, which further limits the conversion of Ang I to Ang II. Other conditions associated with reduced Ang II levels include Gram-negative sepsis where endotoxinemia can deactivate ACE. Importantly, low levels of Ang II and ACE are associated with increased mortality .
We report the successful management of seven patients (four male; mean age 36 years) with severe cardiorespiratory failure and refractory shock treated with extracorporeal membrane oxygenation (ECMO) who received Ang II in the context of the ATHOS-3 trial  or a compassionate use program (Table 2). Following initiation of Ang II, a profound effect on blood pressure was seen and the doses of vasopressors were reduced quickly. Time to cessation of vasopressors and catecholamines ranged from 16 h to 8 days. Six patients were discharged home alive.
In conclusion, in patients with severe cardio-respiratory failure requiring ECMO, treatment with Ang II in addition to standard supportive care enabled rapid decatecholaminization. Underlying ACE deficiency may be a contributing factor. Further studies are necessary to confirm the findings.
Angiotensin converting enzyme
- Ang I:
- Ang II:
Angiotensin II for the Treatment of Vasodilatory Shock
Extracorporeal membrane oxygenation
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The authors would like to thank the patients for allowing the publication of their anonymized data and contributing to the dissemination of information. We are also grateful to the research nurses and coordinators who helped with the successful conduct of the ATHOS -3 study.
Availability of data and materials
The datasets used and analyzed during the current study are available from the corresponding author on reasonable request.
Ethics approval and consent to participate
The case series includes patients who participated in the ATHOS-3 study or received angiotensin II in the context of a compassionate treatment program. The ATHOS-3 study was fully approved by an independent research ethics committee.
Consent for publication
As part of the ATHOS-3 study, patients gave consent for their data and results to be published in an anonymized format.
The authors declare that they have no competing interests.
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Ostermann, M., Boldt, D.W., Harper, M.D. et al. Angiotensin in ECMO patients with refractory shock. Crit Care 22, 288 (2018). https://doi.org/10.1186/s13054-018-2225-4