To Stop or Not?

Preoperative N-terminal pro-B-type natriuretic peptide and myocardial injury after stopping or continuing renin-angiotensin system inhibitors in noncardiac surgery: a prespecified analysis of a phase 2 randomised controlled multicentre trial

BACKGROUND

Patients with elevated preoperative plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP >100 pg ml-1) experience more complications after noncardiac surgery. Individuals prescribed renin-angiotensin system (RAS) inhibitors for cardiometabolic disease are at particular risk of perioperative myocardial injury and complications. We hypothesised that stopping RAS inhibitors before surgery increases the risk of perioperative myocardial injury, depending on preoperative risk stratified by plasma NT-proBNP concentrations.

METHODS

In a preplanned analysis of a phase 2a trial in six UK centres, patients ≥60 yr old undergoing elective noncardiac surgery were randomly assigned either to stop or continue RAS inhibitors before surgery. The pharmacokinetic profile of individual RAS inhibitors determined for how long they were stopped before surgery. The primary outcome, masked to investigators, clinicians, and patients, was myocardial injury (plasma high-sensitivity troponin-T ≥15 ng L-1 or a ≥5 ng L-1 increase, when preoperative high-sensitivity troponin-T ≥15 ng L-1) within 48 h after surgery. The co-exposures of interest were preoperative plasma NT-proBNP (< or >100 pg ml -1) and stopping or continuing RAS inhibitors.

RESULTS

Of 241 participants, 101 (41.9%; mean age 71 [7] yr; 48% females) had preoperative NT-proBNP >100 pg ml -1 (median 339 [160-833] pg ml-1), of whom 9/101 (8.9%) had a formal diagnosis of cardiac failure. Myocardial injury occurred in 63/101 (62.4%) subjects with NT-proBNP >100 pg ml-1, compared with 45/140 (32.1%) subjects with NT-proBNP <100 pg ml -1 {odds ratio (OR) 3.50 (95% confidence interval [CI] 2.05-5.99); P<0.0001}. For subjects with preoperative NT-proBNP <100 pg ml-1, 30/75 (40%) who stopped RAS inhibitors had myocardial injury, compared with 15/65 (23.1%) who continued RAS inhibitors (OR for stopping 2.22 [95% CI 1.06-4.65]; P=0.03). For preoperative NT-proBNP >100 pg ml-1, myocardial injury rates were similar regardless of stopping (62.2%) or continuing (62.5%) RAS inhibitors (OR for stopping 0.98 [95% CI 0.44-2.22]).

CONCLUSIONS

Stopping renin-angiotensin system inhibitors in lower-risk patients (preoperative NT-proBNP <100 pg ml -1) increased the likelihood of myocardial injury before noncardiac surgery.

Discontinuation vs. continuation of renin-angiotensin system inhibition before non-cardiac surgery: the SPACE trial

BACKGROUND AND AIMS

Haemodynamic instability is associated with peri-operative myocardial injury, particularly in patients receiving renin-angiotensin system (RAS) inhibitors (angiotensin-converting-enzyme inhibitors/angiotensin II receptor blockers). Whether stopping RAS inhibitors to minimise hypotension, or continuing RAS inhibitors to avoid hypertension, reduces peri-operative myocardial injury remains unclear.

METHODS

From 31 July 2017 to 1 October 2021, patients aged ≥60 years undergoing elective non-cardiac surgery were randomly assigned to either discontinue or continue RAS inhibitors prescribed for existing medical conditions in six UK centres. Renin-angiotensin system inhibitors were withheld for different durations (2-3 days) before surgery, according to their pharmacokinetic profile. The primary outcome, masked to investigators, clinicians, and patients, was myocardial injury [plasma high-sensitivity troponin-T (hs-TnT) ≥ 15 ng/L within 48 h after surgery, or ≥5 ng/L increase when pre-operative hs-TnT ≥15 ng/L]. Pre-specified adverse haemodynamic events occurring within 48 h of surgery included acute hypertension (>180 mmHg) and hypotension requiring vasoactive therapy.

RESULTS

Two hundred and sixty-two participants were randomized to continue (n = 132) or stop (n = 130) RAS inhibitors. Myocardial injury occurred in 58 (48.3%) patients randomized to discontinue, compared with 50 (41.3%) patients who continued, RAS inhibitors [odds ratio (for continuing): 0.77; 95% confidence interval (CI) 0.45-1.31]. Hypertensive adverse events were more frequent when RAS inhibitors were stopped [16 (12.4%)], compared with 7 (5.3%) who continued RAS inhibitors [odds ratio (for continuing): 0.4; 95% CI 0.16-1.00]. Hypotension rates were similar when RAS inhibitors were stopped [12 (9.3%)] or continued [11 (8.4%)].

CONCLUSIONS

Discontinuing RAS inhibitors before non-cardiac surgery did not reduce myocardial injury, and could increase the risk of clinically significant acute hypertension. These findings require confirmation in future studies.

The effect of continuing versus withholding angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers on mortality and major adverse cardiovascular events in hypertensive patients undergoing elective non-cardiac surgery: study protocol for a multi-centric open-label randomised controlled trial

BACKGROUND

Angiotensin-converting enzyme inhibitors (ACEIs)/angiotensin receptor blockers (ARBs) are commonly prescribed to patients with hypertension. These drugs are cardioprotective in addition to their blood pressure-lowering effects. However, it is debatable whether hypertensive patients who present for non-cardiac surgery should continue or discontinue these drugs preoperatively. Continuing the drugs entails the risk of perioperative refractory hypotension and/or angioneurotic oedema, while discontinuing the drugs entails the risk of rebound hypertension and myocardial ischaemia. The aim of this study is to evaluate the effect of continuation vs withholding of ACEIs/ARBs on mortality and other major outcomes in hypertensive patients undergoing elective non-cardiac surgery.

METHODS

The continuing vs withholding of ACEIs/ARBs in patients undergoing non-cardiac surgery is a prospective, multi-centric, open-label randomised controlled trial. Two thousand one hundred hypertensive patients receiving ACEIs/ARBs and planned for elective non-cardiac surgery will be enrolled. They will be randomised to either continue the ACEIs/ARBs including on the day of surgery (group A) or to withhold it 24-36 h before surgery (group B). The primary endpoint will be the difference in the composite outcome of all-cause in-hospital/30-day mortality and major adverse cardiovascular and non-cardiovascular events. Secondary endpoints will be to evaluate the differences in perioperative hypotension, angioneurotic oedema, myocardial injury, ICU and hospital stay. The impact of the continuation vs withholding of the ACEIs/ARBs on the incidence of case cancellation will also be studied.

DISCUSSION

The results of this trial should provide sufficient evidence on whether to continue or withhold ACEIs/ARBs before major non-cardiac surgery.

TRIAL REGISTRATION

Clinical Trials Registry of India CTRI/2021/01/030199. Registered on 4 January 2021.

Impact of renin-angiotensin system inhibitors continuation versus discontinuation on outcome after major surgery: protocol of a multicenter randomized, controlled trial (STOP-or-NOT trial)

BACKGROUND

Chronic treatment of hypertension or heart failure very often includes an angiotensin-converting enzyme inhibitors (ACE-Is) or angiotensin receptor blockers (ARBs) as renin-angiotensin system inhibitors (RASi) treatments. To stop or not to stop these medications before major surgery remains an unresolved issue. The lack of evidence leads to conflicting guidelines with respect to RASi management before major surgery. The purpose of this study is to evaluate the impact of a strategy of RASi continuation or discontinuation on perioperative complications in patients undergoing major non-cardiac surgery.

METHODS

This is a multicenter, open-labeled randomized controlled trial in > 30 French centers. In the experimental group, RASi will be continued while the treatment will be stopped 48 h before the surgery in the control arm. The primary endpoint is a composite endpoint of major complications after surgery. An endpoint adjudication committee will review clinical data and adjudicate efficacy endpoints while blinded to the assigned study drug group. Main analysis will be by intention-to-treat comparing the composite outcome measure at 28 days in the two groups. A total of 2222 patients are planned to detect an absolute complications difference of 5%.

DISCUSSION

The results of the trial should provide robust evidence to anesthesiologists and surgeons regarding management of RASi before major non-cardiac surgery.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03374449 . Registered on 11 December 2017.

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.

Can ACE-I Be a Silent Killer While Normal Renal Functions Falsely Secure Us?

The current case report represents a warning against serious hyperkalaemia and acidosis induced by ACE-I during surgical stress while normal renal function could deceive the attending anaesthetist. Arterial gas analysis for follow-up of haemoglobin loss accidentally discovered hyperkalaemia and acidosis. Glucose-insulin and furosemide successfully corrected hyperkalaemia after 25 minutes and acidosis after 3 hours. These complications could be explained by a deficient steroid stress response to surgery secondary to suppression by ACE-I. Event analysis and database search found that ACE-I induced aldosterone deficiency aggravated by surgical stress response with an inadequate increase in aldosterone secretion due to angiotensin II deficiency as a sequel of ACE-I leading to defective secretion of H+ and K+. Furosemide is recommended to secrete H+ and K+ compensating for aldosterone deficiency in addition to other antihyperkalaemia measures. Anaesthetising an ACE-I treated patient requires considering ACE-I as a potential cause of hyperkalaemia and acidosis.

Intravenous Fluids in AKI: A Mechanistically Guided Approach

Acute kidney injury (AKI) has been associated with an increased risk of death and morbidity in many clinical scenarios. The prevention and treatment of AKI therefore has been advocated as a high-priority research focus. However, nearly all strategies tested in this setting have failed to prevent or cure AKI and fluid loading remains a cornerstone of preventive and curative treatment of AKI. Concerns have been raised, however, regarding both the efficacy and safety of fluid loading to prevent or reverse AKI. In this review, we address the question of the best use of fluid loading based on current preclinical and clinical data in a mechanistically guided approach. Impacts of fluid resuscitation on renal hemodynamics, from macrocirculation to microcirculation, with physiological end points as well as renal consequences of different fluids available are discussed. Finally, the complex relationship between renal hemodynamics is discussed.

Withholding versus Continuing Angiotensin-converting Enzyme Inhibitors or Angiotensin II Receptor Blockers before Noncardiac Surgery

Background

The effect on cardiovascular outcomes of withholding angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers in chronic users before noncardiac surgery is unknown.

Methods

In this international prospective cohort study, the authors analyzed data from 14,687 patients (including 4,802 angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker users) at least 45 yr old who had in-patient noncardiac surgery from 2007 to 2011. Using multivariable regression models, the authors studied the relationship between withholding angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers and a primary composite outcome of all-cause death, stroke, or myocardial injury after noncardiac surgery at 30 days, with intraoperative and postoperative clinically important hypotension as secondary outcomes.

Results

Compared to patients who continued their angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers, the 1,245 (26%) angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker users who withheld their angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers in the 24 h before surgery were less likely to suffer the primary composite outcome of all-cause death, stroke, or myocardial injury (150/1,245 [12.0%] vs. 459/3,557 [12.9%]; adjusted relative risk, 0.82; 95% CI, 0.70 to 0.96; P = 0.01) and intraoperative hypotension (adjusted relative risk, 0.80; 95% CI, 0.72 to 0.93; P &lt; 0.001). The risk of postoperative hypotension was similar between the two groups (adjusted relative risk, 0.92; 95% CI, 0.77 to 1.10; P = 0.36). Results were consistent across the range of preoperative blood pressures. The practice of withholding angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers was only modestly correlated with patient characteristics and the type and timing of surgery.

Conclusions

Withholding angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers before major noncardiac surgery was associated with a lower risk of death and postoperative vascular events. A large randomized trial is needed to confirm this finding. In the interim, clinicians should consider recommending that patients withhold angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers 24 h before surgery.