This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Dupuis, J.-Y. Articles by Godet, G. Search for Related Content PubMed PubMed Citation Articles by Dupuis, J.-Y. Articles by Godet, G.

---

LETTERS TO THE EDITOR

Against the Discontinuation of Angiotensin II Antagonists Before Surgery

Department of AnesthesiaUniversity of Ottawa Heart InstituteOttawa, Ontario

To the Editor:

The clinical investigation by Bertrand et al. (1) demonstrates the increased hypotensive effect of propofol and sufentanil when used for induction of anesthesia in patients treated with angiotensin II antagonists (AIIA). However, the conclusion that "These results suggest the need to discontinue the AIIA on the day before operation" is too strong and possibly wrong. None of the patients in the study had a major perioperative complication, whether or not the AIIA were withheld before surgery. The only significant differences between the two groups were a higher incidence of intraoperative hypotensive episodes and a higher requirement for vasopressors in the patients treated with AIIA until surgery. The same anesthetic protocol was used in both groups of patients and the proportional decrease in systolic arterial pressure was very similar in both groups, as shown in Figure 1 of their manuscript (1). Considering those findings and the fact that those results do not necessarily apply to different anesthetic drug regimens, a more appropriate conclusion would be "The induction of anesthesia with propofol and sufentanil may lead to very low systolic blood pressure in some patients chronically treated with AIIA before surgery. Consequently, anesthetists should carefully titrate the doses of propofol and sufentanil in this population and be prepared to use more potent vasopressors in case of hypotension not responding to the usual doses of ephedrine or phenylephrine."

Before suggesting the discontinuation of any useful chronic treatment before surgery, anesthetists should remember the lesson learned from the use of ß-adrenergic blockers over the last three decades. In 1972, it was recommended to discontinue propanolol (the only clinically available ß-blocker at the time) 2 wk before surgery because of its potential myocardial depressive effect during the perioperative period (2). The last sentence of the article stated "It is unlikely that the disease will progress as a result of withholding this drug" (2). Time and experience have taught us the contrary. They have also taught us that perioperative care can be adapted to the intrinsic effects of various drugs taken by surgical patients. In some cases (e.g., with ß-adrenergic blockers), this may even be associated with improved perioperative outcome (3). This can only be achieved with a good understanding of the effects and interactions of cardiovascular drugs with anesthetic drugs. With this perspective in mind, the study by Bertrand et al. (1) provides valuable information regarding the AIIA interactions with anesthetic drugs, despite a debatable conclusion. Anesthetists can use that information consequently, and adapt their anesthesia plan to individual patients without unnecessarily discontinuing an efficacious chronic therapy.

References

1. Bertrand M, Godet G, Meersschaert K, et al. Should the angiotensin II antagonists be discontinued before surgery? Anesth Analg 2001; 92: 26–30.[Abstract/Free Full Text]
2. Viljoen JF, Estafanous FG, Kellner GA. Propanolol and cardiac surgery. J Thorac Cardiovasc Surg 1972; 64: 826–30.[Medline]
3. Mangano DT, Layug LE, Wallace A, Tateo I. Effect of atenolol on mortality and cardiovascular morbidity after noncardiac surgery. N Engl J Med 1996; 335: 1713–20.[Abstract/Free Full Text]

Response

Department of AnesthesiologyPitie-Salpetriere HospitalParis, France

In Response:

We appreciate Dr. Dupuis’ interest in our recent article and thank him for his comments. To assess whether angiotensin II antagonists (AIIA) therapy should be continued until surgery, a standard practice for other antihypertensive drugs except for angiotensin-converting enzyme inhibitors (ACEI), we investigated the following in this study: 1) whether stopping the treatment did or did not lead to a hypertensive episode before surgery, at intubation, or during recovery; and 2) whether continuing treatment was or was not associated with an unacceptable decrease in blood pressure at induction. Our data obtained in patients chronically treated for essential hypertension with AIIA demonstrate that withdrawal of AIIA therapy on the day before surgery does not result in a higher incidence of hypertensive episodes during anesthesia and at recovery. But, in contrast, hypotensive episodes and the use of vasoconstrictive drugs were more frequent in these patients.

The exaggerated hypotensive response to induction in patients receiving AIIA is explained by the fact that angiotensin II contributes to hemodynamic regulation during anesthesia (1,2) and has specific effects on the loading conditions of the heart and autonomic system. These mechanisms are enhanced by the presence of preoperative hypovolemia, frequently seen in hypertensive vascular surgical patients. As suggested by Dr. Dupuis, anesthesiologists should carefully titrate the doses of anesthetic drugs according to hemodynamics. Nevertheless, AIIA may impair this titration. In a previous study, we compared the profoundness of anesthesia as supported by Bispectral index in patients chronically treated with AIIA, ACEI, or neither, and receiving the same anesthesia. As a result, AIIA appear to not modify the profoundness of anesthesia (3). Consequently, we prefer to adapt anesthetic regimen not only to hemodynamics but also to a real level of the profoundness of anesthesia.

At last, we agree with Dr. Dupuis on the necessity of not withholding major chronic treatment as ß-adrenergic or calcium channel-blockers before surgery. In contrast, withdrawal of ACEI or AIIA on the day before operation seems to not be deleterious when these drugs are retaken immediately after the surgery. The future will say.

References

1. Miller ED, Longnecker DE, Peach MJ. The regulatory function of the renin-angiotensin system during general anesthesia. Anesthesiology 1978; 48: 399–403.[Web of Science][Medline]
2. Miller ED, Ackerly JA, Peach MJ. Blood pressure support during general anesthesia in a renin-dependent state in the rat. Anesthesiology 1978; 48: 404–8.[Web of Science][Medline]
3. Soriano C, Godet G, Agosti A, et al. Converting enzyme or angiotensin II antagonists do not potentiate anesthetic drugs as demonstrate by BIS monitoring. Eur J Anaesth 2000; 00 (suppl19): A279.

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Dupuis, J.-Y. Articles by Godet, G. Search for Related Content PubMed PubMed Citation Articles by Dupuis, J.-Y. Articles by Godet, G.