Angiotensin-Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers Before Elective Noncardiac Surgery

Propofol Versus Remifentanil Sedation for Transcatheter Aortic Valve Replacement: A Single Academic Center Experience

OBJECTIVE

Comparison of remifentanil versus propofol for sedation during transcatheter aortic valve replacement (TAVR) procedures to analyze the risk of sedation-related hypoxemia and hypotension. Secondary outcomes included the rate of conversion to general anesthesia, procedure length, rate of intensive care unit (ICU) admission, ICU and hospital lengths of stay, and 30-day mortality.

DESIGN

Retrospective cohort study.

SETTING

A single tertiary teaching hospital.

PARTICIPANTS

Two hundred fifty-nine patients who had propofol or remifentanil sedation for TAVR between March 2017 and March 2020.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

There were 130 patients (50.2%) in the propofol cohort and 129 patients (49.8%) in the remifentanil cohort. The primary outcomes were oxygen saturation nadir values and vasopressor infusion use. Remifentanil was associated with a lower oxygen saturation nadir, as compared to propofol (91.3% v . 95.4%, p < 0.001). Risk factors associated with hypoxemia (defined as <92%) were body mass index (p = 0.0004), obstructive sleep apnea (p = 0.004), and remifentanil maintenance (p < 0.001). Vasopressor infusion use was significantly higher with propofol (64.9% v . 8.5%, p < 0.001). Propofol maintenance and angiotensin-converting enzyme inhibitor/angiotensin II receptor-blocker use were the only variables identified as risk factors for vasopressor use (p < 0.001 and p = 0.009).

CONCLUSIONS

For patients undergoing TAVR with conscious sedation, remifentanil was associated with more hypoxemia while propofol was associated with a higher rate of vasopressor use.

Angiotensin axis blockade, acute kidney injury, and perioperative morbidity in patients undergoing colorectal surgery: A retrospective cohort study

Patients undergoing surgery and taking angiotensin converting enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARB) are susceptible to complications related to intraoperative hypotension. Perioperative continuation of such medications in patients undergoing colorectal surgery may be associated with more harm than benefit, as these patients are often exposed to other risk factors which may contribute to intraoperative hypotension. Our objectives were to assess the incidence and severity of postinduction hypotension as well as the rates of acute kidney injury (AKI), 30-day all-cause mortality, 30-day readmission, and hospital length of stay in adult patients undergoing colorectal surgery who take ACEi/ARB.We performed a retrospective chart review of patients undergoing colorectal surgery of ≥4 hour duration at a tertiary care academic medical center between January 2011 and November 2016. The preoperative and intraoperative characteristics as well as postoperative outcomes were compared between patients taking ACEi/ARB and patients not taking these medications.Of the 1020 patients meeting inclusion criteria, 174 (17%) were taking either ACEi or ARB before surgery. Patients taking these medications were more likely to receive both postinduction and intraoperative phenylephrine and ephedrine. The incidences of postoperative AKI (P = .35), 30-day all-cause mortality (P = .36), 30-day hospital readmission (P = .45), and hospital length of stay (P = .25), were not significantly different between the 2 groups.Our results support the current recommendation that ACEi/ARB use is probably safe within the colorectal surgery population during the perioperative period. Intraoperative hypotension should be expected and treated with vasopressors.

A randomized controlled trial comparing methohexital and propofol for induction in patients receiving angiotensin axis blockade

BACKGROUND

Pharmacologic angiotensin axis blockade (AAB) has been associated with profound hypotension following anesthetic induction with propofol. To combat this problem, investigators have attempted to withhold angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARB) preoperatively, or evaluated the effects of different induction agents in conferring greater hemodynamic stability. To date, methohexital has not been compared with the most commonly used induction agent, propofol. Hence, the primary objective was to study the hypothesis that methohexital confers a better hemodynamic profile than propofol for anesthetic induction, in patients receiving AAB. The secondary objective was to investigate the postinduction levels of serum neurohormones in an attempt to explain the mechanisms involved.

METHODS

Forty-five adult, hypertensive patients taking ACEi or ARB and scheduled for elective, noncardiac surgery completed the study. Patients were randomized to receive equi-anesthetic doses of either propofol or methohexital for anesthetic induction. Hemodynamic variables were measured and blood samples were drawn before induction and for 15 minutes afterwards.

RESULTS

Methohexital resulted in less hypotension compared with propofol (P = .01), although the degree of refractory hypotension was similar (P = .37). The postinduction systolic blood pressure (P = .03), diastolic blood pressure (P < .001) and heart rate (P = .03) were significantly higher in the methohexital group. A nonsignificant elevation of serum norepinephrine and epinephrine levels was observed in the methohexital group, while serum arginine vasopressin and angiotensin II levels did not differ between groups.

CONCLUSION

While methohexital was shown to confer greater hemodynamic stability in patients taking ACEi/ARB, the measured hormone levels could not explain the mechanism for this effect.