Chronic Angiotensin-Converting Enzyme Inhibitor or Angiotensin Receptor Blocker Therapy Combined With Diuretic Therapy is Associated With Increased Episodes of Hypotension in Noncardiac Surgery

Comparison of hypotension incidence between remimazolam and propofol in patients with hypertension undergoing neurosurgery: prospective, randomized, single-blind trial

BACKGROUND

Remimazolam, a newer benzodiazepine that targets the GABAA receptor, is thought to allow more stable blood pressure management during anesthesia induction. In contrast, propofol is associated with vasodilatory effects and an increased risk of hypotension, particularly in patients with comorbidities. This study aimed to identify medications that can maintain stable vital signs throughout the induction phase.

METHODS

We conducted a single-center, two-group, randomized controlled trial to investigate and compare the incidence of hypotension between remimazolam- and propofol-based total intravenous anesthesia (TIVA). We selected patients aged between 19 and 75 years scheduled for neurosurgery under general anesthesia, who were classified as American Society of Anesthesiologists Physical Status I-III and had a history of hypertension.

RESULTS

We included 94 patients in the final analysis. The incidence of hypotension was higher in the propofol group (91.3%) than in the remimazolam group (85.4%; P = 0.057). There was no significant difference in the incidence of hypotension among the various antihypertensive medications despite the majority of patients being on multiple medications. In comparison with the propofol group, the remimazolam group demonstrated a higher heart rate immediately after intubation.

CONCLUSIONS

Our study indicated that the hypotension incidence of remimazolam-based TIVA was comparable to that of propofol-based TIVA throughout the induction phase of EEG-guided anesthesia. Both remimazolam and propofol may be equally suitable for general anesthesia in patients undergoing neurosurgery.

TRIAL REGISTRATION

Clinicaltrials.gov (NCT05164146).

Patients with Prior Exposure to a Combination of Statins & Angiotensin-Converting Enzyme Inhibitors (ACE-Is)/Angiotensin Receptor Blockers (ARBs) Have Better Outcomes after Carotid Revascularization than Patients with Prior Exposure to Statins Alone: A MultiCenter Analysis

BACKGROUND

Statin use has been studied and confirmed to have a beneficial impact on perioperative carotid endarterectomy (CEA) and carotid artery stenting (CAS) outcomes. The benefits of Angiotensin-converting enzyme inhibitors (ACE-I) in hypertension, ischemic heart disease, heart failure, diabetes mellitus, and renal disease are well-known; however, the impact of continuing or withholding ACE-Is/angiotensin receptor blockers (ARBs) on CEA and CAS outcomes is not addressed well in the literature. This study aimed to evaluate the impact of preoperative statin use combined with ACE-Is/ARBs in patients undergoing CEA or CAS on mortality and morbidity using a multi-institutional database.

METHODS

Using the data of all patients who underwent carotid artery revascularization, including CEA, transcarotid artery revascularization, and transfemoral carotid artery stenting from 2016 to 2021 in the Vascular Quality Initiative data, we determined as our primary outcome 30-day mortality/stroke after carotid revascularization based on periop exposure to statins alone, or the combination of statins and ACE-Is/ARBs. Secondary outcomes were postop myocardial infarction and postop congestive heart failure. Poisson regression with robust variance was used to determine postop outcomes comparing the combination of statin and ACE-Is/ARBs group with statins alone group.

RESULTS

A total of 131,285 patients were included in the study, with 59,860 (46%) patients receiving statin only, and 71,425 (54%) receiving both statin and ACE-Is/ARBs preoperatively. Both patient groups differed significantly in preop clinical and demographic characteristics. After adjusting for potential confounders, the statins plus ACE-I/ARB group had a 12% lower risk of postop mortality/stroke (Incident Rate Ratio comparing Statin/ACE group to Statins Only group [IRR] 0.88, 95% confidence interval 0.81-0.95, P = 0.001), 18% lower risk of postop congestive heart failure (IRR 0.82, 95% CI 0.68-0.98, P = 0.029), and similar risk of postop myocardial infarction (IRR 1.05 95% confidence interval 0.91-1.20, P = 0.54) compared to the statin-only group.

CONCLUSION

Statins combined with ACE-Is/ARBs perioperatively offer better protection compared to statins alone in patients undergoing carotid revascularization surgery. We recommend the continuation of ACE-Is/ARBs use in patients undergoing carotid revascularization, especially if they have concurrent hypertension. Further prospective studies are needed to evaluate the benefit of adding ACE-Is/ARBs.

Perioperative Management of Novel Pharmacotherapies for Heart Failure and Pulmonary Hypertension

Heart failure (HF) and pulmonary hypertension (PH) are increasingly prevalent comorbidities in patients presenting for noncardiac surgery. The unique pathophysiology and pharmacotherapies associated with these syndromes have important perioperative implications. As new medications for HF and PH emerge, it is imperative that anesthesiologists and other perioperative providers understand their mechanisms of action, pharmacokinetics, and potential adverse effects. We present an overview of the novel HF and PH pharmacotherapies and strategies for their perioperative management.

Perioperative cardiac risk reduction in non cardiac surgery

For patients undergoing nonemergent noncardiac surgery, care must be taken to identify patients at increased risk of major adverse cardiovascular events, as these remain a significant source of perioperative morbidity and mortality. Identification of at-risk patients requires careful attention to risk factors including assessment of functional status, medical comorbidities, and a medication assessment. After identification, to minimize perioperative cardiac risk, care should be taken through a combination of appropriate medication management, close monitoring for cardiovascular ischemic events, and optimization of pre-existing medical conditions. There are multiple society guidelines that aim to mitigate risk of cardiovascular morbidity and mortality in patients undergoing nonemergent noncardiac surgery. However, the rapid evolution of medical literature often creates gaps between the existing evidence and best practice recommendations. In this review, we aim to reconcile the recommendations made in the guidelines from the major cardiovascular and anesthesiology societies from the USA, Canada, and Europe, and to provide updated recommendations based on new evidence.

Blockade of endothelial Mas receptor restores the vasomotor response to phenylephrine in human resistance arterioles pretreated with captopril and exposed to propofol

Background

Hypotension that is resistant to phenylephrine is a complication that occurs in anesthetized patients treated with angiotensin converting enzyme (ACE) inhibitors. We tested the hypothesis that Ang 1–7 and the endothelial Mas receptor contribute to vasodilation produced by propofol in the presence of captopril.

Methods

The internal diameters of human adipose resistance arterioles were measured before and after administration of phenylephrine (10^–9 to 10^–5 M) in the presence and absence of propofol (10^–6 M; added 10 min before the phenylephrine) or the Mas receptor antagonist A779 (10^–5 M; added 30 min before phenylephrine) in separate experimental groups. Additional groups of arterioles were incubated for 16 to 20 h with captopril (10^–2 M) or Ang 1–7 (10^–9 M) before experimentation with phenylephrine, propofol, and A779.

Results

Propofol blunted phenylephrine-induced vasoconstriction in normal vessels. Captopril pretreatment alone did not affect vasoconstriction, but the addition of propofol markedly attenuated the vasomotor response to phenylephrine. A779 alone did not affect vasoconstriction in normal vessels, but it restored vasoreactivity in arterioles pretreated with captopril and exposed to propofol. Ang 1–7 reduced the vasoconstriction in response to phenylephrine. Addition of propofol to Ang 1–7-pretreated vessels further depressed phenylephrine-induced vasoconstriction to an equivalent degree as the combination of captopril and propofol, but A779 partially reversed this effect.

Conclusions

Mas receptor activation by Ang 1–7 contributes to phenylephrine-resistant vasodilation in resistance arterioles pretreated with captopril and exposed to propofol. These data suggest an alternative mechanism by which refractory hypotension may occur in anesthetized patients treated with ACE inhibitors.

Reported definitions of intraoperative hypotension in adults undergoing non-cardiac surgery under general anaesthesia: a review

Background

Intraoperative hypotension (IOH) during non-cardiac surgery is common and associated with major adverse kidney, neurological and cardiac events and even death. Given that IOH is a modifiable risk factor for the mitigation of postoperative complications, it is imperative to generate a precise definition for IOH to facilitate strategies for avoiding or treating its occurrence. Moreover, a universal and consensus definition of IOH may also facilitate the application of novel and emerging therapeutic interventions in treating IOH. We conducted a review to systematically record the reported definitions of intraoperative hypotension in adults undergoing non-cardiac surgery under general anaesthesia.

Methods

In accordance with Cochrane guidelines, we searched three online databases (OVID [Medline], Embase and Cochrane Library) for all studies published from 1 January 2000 to 6 September 2020. We evaluated the number of studies that reported the absolute or relative threshold values for defining blood pressure. Secondary aims included evaluation of the threshold values for defining IOH, the methodology for accounting for the severity of hypotension, whether the type of surgical procedure influenced the definition of IOH, and whether a study whose definition of IOH aligned with the Perioperative Quality Initiative-3 workgroup (POQI) consensus statement for defining was more likely to be associated with determining an adverse postoperative outcome.

Results

A total of 318 studies were included in the final qualitative synthesis. Most studies (n = 249; 78.3%) used an absolute threshold to define hypotension; 150 (60.5%) reported SBP, 117 (47.2%) reported MAP, and 12 (4.8%) reported diastolic blood pressure (DBP). 126 (39.6%) used a relative threshold to define hypotension. Of the included studies, 153 (48.1%) did not include any duration variable in their definition of hypotension. Among the selected 318 studies 148 (46.5%) studies defined IOH according to the POQI statement. When studies used a “relative blood pressure change” to define IOH, there was a weaker association in detecting adverse postoperative outcomes compared to studies who reported “absolute blood pressure change” (χ²(2) = 10.508, P = 0.005, Cramér’s V = 0.182). When studies used the POQI statement definition of hypotension or defined IOH by values higher than the POQI statement definition there were statistical differences observed between IOH and adverse postoperative outcomes (χ²(1) = 6.581, P = 0.037, Cramér’s V = 0.144). When both the duration of IOH or the numbers of hypotensive epochs were evaluated, we observed a significantly stronger relationship between the definition of IOH use the development of adverse postoperative outcomes. (χ²(1) = 4.860, P = 0.027, Cramér’s V = 0.124).

Conclusions

Most studies defined IOH by absolute or relative changes from baseline values. There are substantial inconsistencies in how IOH was reported. Further, definitions differed across different surgical specialities. Our findings further suggest that IOH should be defined using the absolute values stated in the POQI statement i.e., MAP < 60–70 mmHg or SBP < 100 mmHg. Finally, the number of hypotensive epochs or time-weighted duration of IOH should also be reported.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-022-01605-9.

Management of renin-angiotensin-aldosterone inhibitors and other antihypertensives and their clinical effects on pre-anesthesia blood pressure

Background

Blood pressure fluctuations appear more significant in patients with poorly controlled hypertension and are known to be associated with adverse perioperative morbidity. In the present study, we aimed to determine the effects of antihypertensive drug treatment strategies on preanesthetic operating room blood pressure measurements.

Methods

A total of 717 patients participated in our study; 383 patients who were normotensive based on baseline measurements and not under antihypertensive therapy were excluded from the analysis. The remaining 334 patients were divided into six groups according to the antihypertensive drug treatment. These six groups were examined in terms of preoperative baseline and pre-anesthesia blood pressure measurements.

Results

As a result of the study, it was observed that 24% of patients had high blood pressure precluding surgery, and patients using renin-angiotensin-aldosterone system inhibitors (RAASI) had higher pre-anesthesia systolic blood pressure than patients using other antihypertensive drugs. Patients who received beta-blockers were also observed to have the lowest pre-anesthesia systolic blood pressure, diastolic blood pressure, and mean blood pressure, compared to others.

Conclusions

Recently, whether RAASI should be continued preoperatively remains controversial. Our study shows that RAASI cannot provide optimal pre-anesthesia blood pressure and lead to an increase in the number of postponed surgeries, probably due to withdrawal of medication before the operation. Therefore, the preoperative discontinuation of RAASI should be reevaluated in future studies.

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.

ACE-Inhibitor or ARB-Induced Refractory Hypotension Treated With Vasopressin in Patients Undergoing General Anesthesia for Dentistry: Two Case Reports

Two case reports present the use of vasopressin for treating refractory hypotension associated with continued angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) therapy prior to general anesthesia for oral surgery. Both patients were treated in an ambulatory dental surgery clinic and took either their ACEI or ARB medication for hypertension within 24 hours prior to undergoing an intubated general anesthetic. Persistent profound hypotension was encountered intraoperatively that was refractory to treatment with traditional methods. However, the ACEI- or ARB-induced refractory hypotension was successfully managed with the administration of vasopressin.

Association of 5-aminolevulinic acid with intraoperative hypotension in malignant glioma surgery

BACKGROUND

Use of 5-aminolevulinic acid for photodynamic malignant tumor diagnosis reportedly causes intraoperative hypotension (systolic blood pressure < 70 mmHg) during urologic surgery. However, its association with intraoperative hypotension in malignant glioma surgery and underlying mechanisms has not yet been elucidated.. This study aimed to investigate whether 5-aminolevulinic acid administration is associated with intraoperative hypotension in malignant glioma surgery and explore the mechanisms of 5-aminolevulinic acid-induced hypotension in vitro.

METHODS

In this retrospective multicenter cohort study, we investigated intracellular nitric oxide as a candidate mediator of hypotension in response to 5-aminolevulinic acid in vitro in human umbilical vein endothelial cell cultures.

RESULTS

Of 142 patients, 94 underwent 5-aminolevulinic acid-guided surgery. Systolic blood pressure was significantly lower throughout surgery with 5-aminolevulinic acid administration. 5-Aminolevulinic acid administration was an independent risk factor for intraoperative hypotension according to multivariable logistic regression analysis (89% vs. 56%; odds ratio = 6.72, 95% confidence interval [2.05-22.1], P = 002). In subgroup analysis of the 5-aminolevulinic acid group, increasing age and use of renin-angiotensin system inhibitors had a synergistic effect with 5-aminolevulinic acid on decreased blood pressure. In the vascular endothelial cell culture study, 5-aminolevulinic acid induced a significant increase in intracellular nitric oxide generation.

CONCLUSIONS

5-Aminolevulinic acid administration was associated with intraoperative hypotension in malignant glioma surgery, with increasing age and use of renin-angiotensin system inhibitors boosting the blood pressure-lowering effect of 5-aminolevulinic acid. According to in vitro results, the low blood pressure induced by 5-aminolevulinic acid may be mediated by a nitric oxide increase in vascular endothelial cells.

Perioperative Cardiac Risk Reduction in Noncardiac Surgery

Major adverse cardiovascular events are a significant source of morbidity and mortality in the perioperative setting, estimated to occur in approximately 5% of patients undergoing nonemergent noncardiac surgery. To minimize the incidence and impact of these events, careful attention must be paid to preoperative cardiovascular assessment to identify patients at high risk of cardiovascular complications. Once identified, cardiovascular risk reduction is achieved through optimization of medical conditions, appropriate management of medication, and careful monitoring to allow for early identification of-and intervention for-any new conditions that would increase the risk of adverse cardiovascular outcomes. The major cardiovascular and anesthesiology societies in the United States, Europe, and Canada have published guidelines for perioperative management of patients undergoing noncardiac surgery. However, since publication of these guidelines, there has been a practice-changing evolution in the medical literature. In this review, we attempt to reconcile the recommendations made in these 3 comprehensive guidelines, while updating recommendations, based on new evidence, when available.

Arterial Stiffness Predicts General Anesthesia-Induced Vasopressor-Resistant Hypotension in Patients Taking Angiotensin-Converting Enzyme Inhibitors

OBJECTIVES

Patients chronically treated with angiotensin-converting enzyme inhibitors (ACEIs) may develop hypotension after induction of general anesthesia. A fraction of these patients are resistant to therapeutic doses of vasopressors, which poses serious concerns for hemodynamic management. The authors hypothesized that the patients who develop refractory hypotension, compared with those who do not, show lower central arterial stiffness due to the profound effect of ACEIs.

DESIGN

Prospective observational study.

SETTING

Single tertiary center.

INTERVENTIONS

Fifty surgical patients chronically treated with ACEIs were enrolled. Prior to surgery, all the patients had central arterial stiffness assessment measured by carotid-femoral pulse-wave velocity. Patients were categorized into 2 groups according to the systolic blood pressure response during the first 10 minutes after induction of general anesthesia: a vasopressor-resistant hypotension group requiring more than 200 µg phenylephrine, or a control group requiring no more than 200 µg of phenylephrine to maintain systolic blood pressure above 90 mmHg during the study period.

MEASUREMENTS AND MAIN RESULTS

Carotid-femoral pulse-wave velocity was significantly lower in the vasopressor-resistant hypotension group compared to the control group (7.6 [7.2-8.3] m/s v 9.9 [8.7-12.0] m/s, p = 0.001 [Hodges-Lehman median difference 2.2, 95% confidence interval = 1.1-4.4]).

CONCLUSION

These findings suggested that preoperative measurement of carotid-femoral pulse-wave velocity in patients chronically treated with ACEIs could help identify patients at increased risk of developing hypotension refractory to vasopressors after induction of general anesthesia.

Continuation of Angiotensin-Converting Enzyme Inhibitors on the Day of Surgery Is Not Associated With Increased Risk of Hypotension Upon Induction of General Anesthesia in Elective Noncardiac Surgeries

OBJECTIVE

The aim of this study was to find out whether the preoperative continuation of angiotensin-converting enzyme inhibitor (ACE-I) or angiotensin II receptor blocker (ARB) treatment is associated with intraoperative hypotension immediately after induction of general anesthesia in elective noncardiac surgeries.

DESIGN

Retrospective cohort study.

SETTING

Single institutional university hospital.

PARTICIPANTS

Four hundred patients who underwent elective noncardiac surgery under general anesthesia, with ACE-I or ARB on their list of preoperative home medications, were included.

INTERVENTION

Preoperative ACE-I and ARB use was evaluated, and patients were divided into an ACE-I/ARB group versus non-ACE-I/ARB group.

MEASUREMENTS

The primary outcome measure was intraoperative hypotension after induction of general anesthesia. The secondary outcome measure was preoperative medication use, medications taken the morning of surgery, induction medication and dosage, and vasopressor medication use during induction.

RESULTS

Three hundred forty-nine patients were included for final analysis. The mean admission American Society of Anesthesiologists status was 2.7 ± 0.5, age 65 ± 11 years, and body mass index 31 ± 6.9 kg/m². There were no statistically significant changes between the no ACE-I/ARB group and the ACE-I/ARB group in systolic blood pressure (p = 0.853), diastolic blood pressure (p = 0.357), and heart rate (p = 0.220) change over the 15 minutes. There was no statistical difference in induction medication dose (propofol, fentanyl, and rocuronium) and pressor use (p = 0.137) for hypotension between the 2 groups. Statistically significant hypotension (p < 0.001) occurred in both groups equally over 15 minutes.

CONCLUSION

Continuation of ACE-I/ARB on the day of surgery was not associated with increased risk of intraoperative hypotension upon induction and within 15 minutes of general anesthesia in elective noncardiac surgeries.

Frequency of Intraoperative Hypotension After the Induction of Anesthesia in Hypertensive Patients with Preoperative Angiotensin-converting Enzyme Inhibitors

Introduction

The renin-angiotensin-aldosterone system (RAAS) is an important target in the treatment of hypertension. Angiotensin-converting enzyme (ACE) inhibitors block the conversion of angiotensin I to angiotensin II. ACE inhibitors not only treat hypertension but also decrease morbidity and mortality in heart failure patients and in patients with acute myocardial infarction. The discontinuation of ACE inhibitors before the surgery is still controversial. To assess the current magnitude of the problem in our population, we aimed to conduct this study, which evaluated the frequency of intraoperative hypotension after the induction of anesthesia in controlled hypertensive patients with preoperative ACE inhibitors.

Material and methods

This descriptive case series study was conducted at a tertiary hospital in a developing country after approval from the Ethics Review Committee. A total of 115 adult patients, from 16 to 60 years of age, who have undergone elective surgery, have controlled hypertension on the desired drugs for at least six months, have no history of any cardiac event, and have taken the drug on the morning of the surgery, were included in the study after written consent. The demographic data of the patients were entered into the proforma. Preoperative systolic, diastolic, and mean arterial pressure were recorded by the researcher or an assignee in the preoperative holding area. The patients were followed in the recovery room by the team conducting the study until 10 minutes after the arrival of the patient in the recovery room. All statistical analyses were performed using Statistical Packages for the Social Sciences version 19 (SPSS Inc., Chicago, IL). p-value ≤0.05 was considered significant.

Results

Of the 115 patients, 56 (48.7%) patients were in the age group between 51 and 60 years of age; 38 patients were between the ages of 41 and 50 years and only 21 patients were 40 years or less. On gender, 68 patients were female and 47 were male. According to body mass index (BMI), the majority of the patients were in the overweight group, amounting to 53 (46%), and 86 (74.78%) patients were known diabetics. Overall, 77 (66.96%) of the patients developed intraoperative hypotension with 41 (35.65%) patients requiring the use of vasopressors in order to correct the hypotension. No statistically significant difference was found between demographic and clinical variables.

Conclusion

Intraoperative hypotension is more frequent in patients with controlled hypertension on ACE inhibitors although more studies need to be conducted on a larger population in order to determine a more definitive result.

Renin-angiotensin system blocker use and the risk of acute kidney injury after colorectal cancer surgery: a population-based cohort study

OBJECTIVES

It is unknown whether preoperative use of ACE inhibitors (ACE-I) or angiotensin receptor blockers (ARBs) affects the risk of acute kidney injury (AKI) after colorectal cancer (CRC) surgery. We assessed the impact of preoperative ACE-I/ARB use on risk of AKI after CRC surgery.

DESIGN

Observational cohort study. Patients were divided into three exposure groups-current, former and non-users-through reimbursed prescriptions within 365 days before the surgery. AKI within 7 days after surgery was defined according to the current Kidney Disease Improving Global Outcome consensus criteria.

SETTING

Population-based Danish medical databases.

PARTICIPANTS

A total of 9932 patients undergoing incident CRC surgery during 2005-2014 in northern Denmark were included through the Danish Colorectal Cancer Group Database.

OUTCOME MEASURE

We computed cumulative incidence proportions (risk) of AKI with 95% CIs for current, former and non-users of ACE-I/ARB, including death as a competing risk. We compared current and former users with non-users by computing adjusted risk ratios (aRRs) using log-binomial regression adjusted for demographics, comorbidities and CRC-related characteristics. We stratified the analyses of ACE-I/ARB users to address any difference in impact within relevant subgroups.

RESULTS

Twenty-one per cent were ACE-I/ARB current users, 6.4% former users and 72.3% non-users. The 7-day postoperative AKI risk for current, former and non-users was 26.4% (95% CI 24.6% to 28.3%), 25.2% (21.9% to 28.6%) and 17.8% (17.0% to 18.7%), respectively. The aRRs of AKI were 1.20 (1.09 to 1.32) and 1.16 (1.01 to 1.34) for current and former users, compared with non-users. The relative risk of AKI in current compared with non-users was consistent in all subgroups, except for higher aRR in patients with a history of hypertension.

CONCLUSIONS

Being a current or former user of ACE-I/ARBs is associated with an increased risk of postoperative AKI compared with non-users. Although it may not be a drug effect, users of ACE-I/ARBs should be considered a risk group for postoperative AKI.

Periprocedural Concerns in the Patient with Renal Disease

Treating patients with kidney disease can be both a difficult and a complex process. Understanding how to care for patients who have kidney disease is essential for lowering perioperative as well as periprocedural morbidity and mortality. The primary aim in renal evaluation and care is to control and mitigate factors that may result in acute kidney injury (AKI) and/or cause further decline in renal function. It is essential for the foot and ankle specialist to recognize patients who are predisposed to developing or already have impairment of renal function.

The Effect of Chronic Consumption of Angiotensin-Converting Enzyme Inhibitors and Angiotensin Receptor Antagonists on Blood Pressure and Inotrope Consumption After Separation from Cardiopulmonary Bypass

Background

Chronic use of renin-angiotensin system (RAS) antagonists (angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor antagonists (ARAS)) can cause hypotension during anesthesia. In some studies hemodynamic instability, including hypotension and its effects on the clinical outcome in patients treated with these drugs during coronary artery bypass graft (CABG) and need to excessive vasoactive drugs in these patient population, has been described. The aim of this study was to evaluate the effect of chronic consumption of ACEIs and ARAS on blood pressure and inotrope consumption during coronary artery bypass graft under cardiopulmonary bypass.

Methods

A total of 200 patients undergoing coronary artery bypass graft surgery, who were treated with either ARAS or ACEIs (n = 100) over at least 2 months, or who were not treated with any RAS antagonists (control group, n = 100) were enrolled. The mean arterial blood pressure, central venous pressure, and need for vasoactive drugs, were measured after induction of anesthesia (T1) before cardiopulmonary bypass (T2) and after separation from (CPB), (T3).

Results

There were no significant differences regarding the mean arterial pressure (case group: T1: 84 ± 7 mmHg, T2: 77 ± 6 mmHg, T3: 83 ± 8 mmHg), (control group: T1: 85 ± 7 mmHg, T2: 81 ± 7 mmHg, T3:84 ± 6 mmHg) between two groups (P > 0.05). Also there were no significant differences regarding mean central venous pressure, mean heart rate, and vasoactive drug consumption between the two groups during the time of intervals.

Conclusions

We found that preoperative (RAS) antagonist’s continuation have not profound hemodynamic changes during coronary artery bypass graft under cardiopulmonary bypass and so we conclude that omitting these drugs before surgery did not have a sufficient advantage to be recommended routinely.

Prospective Randomized Evaluation of Preoperative Angiotensin-Converting Enzyme Inhibition (PREOP-ACEI)

BACKGROUND

Intraoperative hypotension is associated with an increased risk of end organ damage and death. The transient preoperative interruption of angiotensinconverting enzyme inhibitor (ACEI) therapy prior to cardiac and vascular surgeries decreases the occurrence of intraoperative hypotension.

OBJECTIVE

We sought to compare the effect of two protocols for preoperative ACEI management on the risk of intraoperative hypotension among patients undergoing noncardiac, nonvascular surgeries.

DESIGN

Prospective, randomized study.

SETTING

Midwestern urban 489-bed academic medical center.

PATIENTS

Patients taking an ACEI for at least six weeks preoperatively were considered for inclusion.

INTERVENTIONS

Randomization of the final preoperative ACEI dose to omission (n = 137) or continuation (n = 138).

MEASUREMENTS

The primary outcome was intraoperative hypotension, which was defined as any systolic blood pressure (SBP) < 80 mm Hg. Postoperative hypotensive (SBP < 90 mm Hg) and hypertensive (SBP >> 180 mm Hg) episodes were also recorded. Outcomes were compared using Fisher's exact test.

RESULTS

Intraoperative hypotension occurred less frequently in the omission group (76 of 137 [55%]) than in the continuation group (95 of 138 [69%]) (RR: 0.81, 95% CI: 0.67 to 0.97, P = .03, NNH 7.5). Postoperative hypotensive events were also less frequent in the ACEI omission group (RR: 0.49, 95% CI: 0.28 to 0.86, P = .02) than in the continuation group. However, postoperative hypertensive events were more frequent in the omission group than in the continuation group (RR: 1.95, 95%: CI: 1.14 to 3.34, P = .01).

CONCLUSIONS

The transient preoperative interruption of ACEI therapy is associated with a decreased risk of intraoperative hypotension.

REGISTRATION

ClinicalTrials.gov: NCT01669434.

Risk factors for acute kidney injury after percutaneous nephrolithotomy: Implications of intraoperative hypotension

Percutaneous nephrolithotomy (PNL) is a minimally invasive technique for renal stone removal but can cause renal parenchymal injury. Renal stones can also affect renal function. We evaluated the risk factors for acute kidney injury (AKI) after PNL.The study cohort included 662 patients who underwent PNL. Patient characteristics, preoperative laboratory values, intraoperative data, and stone characteristics were collected. Univariate and multivariate logistic regression analyses were performed to identify risk factors for AKI after PNL. Postoperative outcomes such as hospitalization, intensive care unit admission rate and stay duration, and chronic kidney disease were also evaluated.Of the total study series, there were 107 (16.2%) cases of AKI after PNL (AKI group), and 555 (83.8%) patients who showed no injury (no-AKI group). The risk factors for AKI after PNL were found to be a higher preoperative serum uric acid level [odds ratio (OR) = 1.228; 95% confidence interval (95% CI) = 1.065-1.415; P = .005], longer operation time (OR = 1.009; 95% CI = 1.004-1.014; P < .001), and intraoperative hypotension (OR = 12.713; 95% CI = 7.762-20.823; P < .001). Hospitalization and intensive care unit stay duration were significantly longer in the AKI group (8.7 ± 5.2 vs 6.6 ± 2.8 days, P < .001; 0.34 ± 1.74 vs 0.07 ± 0.48 days, P = .002, respectively). Chronic kidney disease was also significantly higher in the AKI group (63.6% vs 32.7%, P = .024).As intraoperative hypotension is an important risk factor for AKI after PNL, which leads to poor postoperative outcomes, it should be prevented or managed vigorously during PNL.

Consequences of continuing renin angiotensin aldosterone system antagonists in the preoperative period: a systematic review and meta-analysis

Background

Patients who use angiotensin-converting enzyme inhibitors (ACEIs)/angiotensin II receptor blockers (ARBs) are prone to developing side effects like hypotension and even refractory hypotension during anesthesia use, and whether ACEIs/ARBs should be continued or discontinued in such patients remains debatable. The present systematic review and meta-analysis was conducted to clarify the consequences of continuing or withholding these drugs, especially with regards to the incidence of intraoperative hypotension, in patients who continue to use ACEIs/ARBs on the day of their scheduled surgery.

Methods

Studies with data pertinent to the incidence of intraoperative hypotension during anesthesia use in patients who continued the use of ACEIs/ARBs on the day of their scheduled surgery were considered for inclusion.

Results

Thirteen studies reporting on the incidences of intraoperative hypotension between patients who continued receiving ACEIs/ARBs and those who did not on the day of their surgical procedure were included. The pooled effects showed that hypotension during anesthesia was more likely to develop in patients who continued to take ACEIs/ARBs when compared to those who did not (RR = 1.41, 95% CI: 1.21–1.64). However, there were no significant differences between these groups of patients with regards to postoperative complications including ST-T abnormalities, myocardial injury, myocardial infarction, stroke, major adverse cardiac events, acute kidney injury, or death (RR = 1.25, 95% CI: 0.76–2.04). The differences remained similar in subgroup analyses and sensitivity analyses.

Conclusions

No sufficient available evidence to recommend discontinuing ACEIs/ARBs on the day of surgery was found in this literature review and meta-analysis. However, anesthetists should be cautious about the risk for intraoperative hypotension in patients chronically receiving ACEIs/ARBs, and should know how to treat it effectively.

Preoperative Hypertension

PURPOSE OF REVIEW

This review will examine the implications for perioperative management of new hypertension guidelines and place these in the context of findings from recent large observational studies.

RECENT FINDINGS

Recent hypertension guidelines highlight the role of ambulatory blood pressure measurement with the implication that isolated preoperative blood pressure measurements are of limited value. There is emerging evidence from large observational studies that both preoperative and intraoperative hypotension are associated with increased risk. It is not clear if this is a particular concern for hypertensive patients.

SUMMARY

Assessment of the hypertensive surgical patient should include blood pressure measurements taken using the correct technique. Preoperative blood pressures of less than 180/100 mmHg are not grounds for deferring surgery in the absence of active comorbid disease. Evidence to guide the perioperative management of patients with higher pressures is scanty and decisions should be made on a case-by-case basis.

Perioperative use of angiotensin-converting-enzyme inhibitors and angiotensin receptor antagonists

STUDY OBJECTIVE

Clinical repercussions of perioperative treatment with ACEIs/ARBs.

DESIGN

Systematic review according to PRISMA statement.

SETTING

Perioperative period.

PATIENTS

29 studies 11 cases/cases series, 12 observational studies and 6 randomized studies.

MEASUREMENTS

Arterial blood pressure differences, refractory hypotension, other comorbidities.

MAIN RESULTS

The studies show different results regarding the topics measured. They are divided in the results regarding blood pressure, long term morbidities and effects in neuraxial anesthesia.

CONCLUSIONS

Withholding AECI/ARBs on the morning prior to surgery could be recommended as a potentially effective measure, with a low level of evidence, in order to reduce the appearance of hypotension in the perioperative period of non-cardiac surgery.

Predictors of Perioperative Acute Kidney Injury in Obese Patients Undergoing Laparoscopic Bariatric Surgery: a Single-Centre Retrospective Cohort Study

BACKGROUND

Obesity has been associated with increased risk of perioperative acute kidney injury (AKI). We aim to establish the incidence of AKI among patients undergoing laparoscopic bariatric surgery and identify potential risk factors.

METHODS

Records of 1230 patients who underwent laparoscopic bariatric surgery in a tertiary centre from 1 December 2009 to 31 January 2014 were retrospectively studied. AKI diagnosis was made by comparing the baseline and post-operative serum creatinine to determine the presence of predefined significant change based on the Kidney Disease: Improving Global Outcomes (KDIGO) definition. Univariate analyses were performed to determine significant clinical factors, and multiple logistic regression analysis was subsequently done to determine independent predictors of AKI.

RESULTS

Thirty-five (2.9 %) patients developed AKI during the first 72 h post-surgery. Multivariate logistic regression analysis revealed impaired renal function (OR 10.429, 95 % CI 3.560 to 30.552), use of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers (OR 3.038, 95 % CI 1.352 to 6.824), and body mass index (OR 1.048, 95 % CI 1.005 to 1.093) as independent predictors of perioperative acute kidney injury in the obese patients who underwent laparoscopic bariatric surgery.

CONCLUSIONS

We found that the incidence of perioperative AKI among patients who underwent laparoscopic bariatric surgery is at 2.9 %. Impaired renal function, use of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers and raised body mass index were found to be independent predictors of AKI. Patients with these risk factors could be considered at risk for developing perioperative AKI, and extra perioperative vigilance should be undertaken.

Continuation of Renin-Angiotensin-Aldosterone Inhibitors Does Not Impact Renal Function Among Patients Undergoing Percutaneous Nephrolithotomy

OBJECTIVE

In the perioperative period, renin-angiotensin-aldosterone system (RAAS) inhibitors may result in cardiovascular and renal functional changes. We sought to determine the acute and chronic renal functional and blood pressure effects of continuing or withdrawing angiotensin-converting enzyme inhibitors (ACE-I) and angiotensin receptor blockers (ARBs) after percutaneous nephrolithotomy (PCNL).

MATERIALS AND METHODS

This was a retrospective review of all patients undergoing PCNL at our institution from 2002 to 2013. Patients on either an ACE-I and/or ARB who received an ACE-I and/or ARB during their surgical hospitalization were matched based on sex, age, and body mass index to patients who had their medication withheld during the postoperative period. The two groups were compared.

RESULTS

A total of 2784 patients underwent PCNL during the study period. At the time of PCNL, 15.2% (423/2784) of patients and 6.5% (181/2784) were prescribed an ACE-I and an ARB, respectively. Fifty-nine percent (248/423) of patients on an ACE-I and 66.9% (121/181) on an ARB received their medication during their postoperative hospitalization. There was no significant difference in average length of stay (2 days vs 2 days), perioperative change in glomerular filtration rate, glomerular filtration rate (GFR) (-0.50 mL/min/1.73 m² vs -2.34 mL/min/1.73 m², p = 0.267), change in GFR at 1 month postoperatively (-4.63 mL/min/1.73 m² vs -5.90 mL/min/1.73 m², p = 0.748), or change in GFR at 1 year (-2.08 mL/min/1.73 m² vs -0.13 mL/min/1.73 m², p = 0.267) between patients who received vs withheld their medication during the postoperative stay.

CONCLUSION

It is safe to continue RAAS inhibitors in patients undergoing PCNL during their operative hospitalization.

Short-Term Angiotensin Subtype 1 Receptor Blockade Does Not Alter the Circulatory Responses to Sympathetic Nervous System Modulation in Healthy Volunteers Before and During Sevoflurane Anesthesia: Results of a Pilot Study

OBJECTIVE

The mechanism of perioperative hypotension in patients taking an angiotensin-receptor blocker up to the time of surgery remains unclear. This study tested the hypothesis that short-term angiotensin-receptor blocker treatment attenuated the sympathetic and vascular responses to autonomic stimuli in volunteers undergoing anesthesia.

DESIGN

Randomized, crossover, blinded, pilot design.

SETTING

Zablocki Veterans Affairs Medical Center, Milwaukee, WI.

PARTICIPANTS

The study comprised 8 male and 6 female healthy, young volunteers (age 23±1.2 years [mean±standard error of the mean]).

INTERVENTIONS

Volunteers were studied after receiving oral placebo or 50 mg of losartan (angiotensin-receptor blocker) for 3 days before each test day. The effectiveness of angiotensin-receptor blocker treatment was confirmed using the mean arterial blood pressure response to intravenous angiotensin II (1-µg bolus). Eight volunteers underwent direct mean arterial pressure and forearm bloodflow measurements during conscious baseline, a cold pressor test, induction of anesthesia, tracheal intubation, maintenance of anesthesia with 1 minimum alveolar concentration of sevoflurane, and airway irritation with 12% desflurane. Six volunteers experienced mean arterial pressure responses to 0.1 mg of phenylephrine at baseline and during 1 minimum alveolar concentration of sevoflurane.

MEASUREMENTS AND MAIN RESULTS

Comparisons were made over time and across groups. Angiotensin-receptor blocker treatment significantly reduced-mean arterial pressure and forearm vascular resistance (forearm blood flow/mean arterial pressure) over time and blocked the mean arterial pressure response to angiotensin-II challenge. The changes in mean arterial pressure and forearm vascular resistance in response to all stressors did not differ between treatments. Mean arterial pressure increases from phenylephrine were preserved.

CONCLUSIONS

In healthy, young volunteers, sympathetically-mediated responses from the short-term use of an angiotensin-receptor blocker were not altered and most likely did not contribute to perioperative hypotension during the intraoperative period.

Perioperative Management of Patients Treated with Angiotensin-Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers: A Quality Improvement Audit

Previous studies have shown that patients continuing angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers on the day of surgery are more likely to have significant intraoperative hypotension, higher rates of postoperative acute kidney injury and lower incidences of postoperative atrial fibrillation. However, many of these studies were prone to bias and confounding, and questions remain over the validity of these outcomes. This observational, before-and-after quality mprovement audit aimed to assess the effect of withholding these medications on the morning of surgery. We recruited 323 participants, with 83 (26%) having their preoperative angiotensin-converting enzyme inhibitor (ACEi) or angiotensin II receptor blocker (ARB) withheld on the day of surgery. There were only very small Spearman rank-order correlations between time since last dose of these medications (rho −0.12, P=0.057) and intraoperative and recovery room intravenous fluid administration (rho −0.11, P=0.042). There was no statistically significant difference between the continued or withheld groups in vasopressor (metaraminol use 3.5 [1.5–8.3] mg versus 3.5 [1.5–8.5] mg, P=0.67) or intravenous fluid administration (1000 ml [800–1500] ml versus 1000 [800–1500] ml, P=0.096), nor rates of postoperative acute kidney injury (13% vs 18%, P=0.25) or atrial fibrillation (15% versus 18%, P=0.71). This audit found no significant differences in measured outcomes between the continued or withheld ACEi/ARB groups. This finding should be interpreted with caution due to the possibility of confounding and an insufficient sample size. However, as the finding is in contrast to many previous studies, future prospective randomised clinical trials are required to answer this important question.

Hypertensive Urgencies and Emergencies in the Hospital Setting

The prevalence of hypertension in the general population has steadily climbed over the past several decades and hypertension is a primary or secondary diagnosis in nearly a fourth of hospitalized adults. Hospitalization is often a time of pertubation in a patient's usual blood pressure control, with pain, anxiety and missed medications all risk factors for severe hypertension. Hospitalists are often faced with severe hypertension in a patient not previously known to them and this presents a challenge of how best to assess the clinical importance of blood pressure elevation. An additional challenge is the lack of literature to guide the optimal management of hypertension in inpatients. This review aims to describe the scope of the problem, to describe the near and long-term risks of overzealous blood pressure management, and to identify areas for future study.

Acute Kidney Injury in the Surgical Patient

Perioperative acute kidney injury (AKI) is a common, morbid, and costly surgical complication. Current efforts to understand and manage AKI in surgical patients focus on prevention, mitigation of further injury when AKI has occurred, treatment of associated conditions, and facilitation of renal recovery. Lesser severity AKI is now understood to be much more common, and more morbid, than was previously thought. The ability to detect AKI within hours of onset would be helpful in protecting the kidney and in preserving renal function, and several imaging and biomarker modalities are currently being evaluated.

Predictors of intraoperative hypotension and bradycardia

BACKGROUND

Perioperative hypotension and bradycardia in the surgical patient are associated with adverse outcomes, including stroke. We developed and evaluated a new preoperative risk model in predicting intraoperative hypotension or bradycardia in patients undergoing elective noncardiac surgery.

METHODS

Prospective data were collected in 193 patients undergoing elective, noncardiac surgery. Intraoperative hypotension was defined as systolic blood pressure <90 mm Hg for >5 minutes or a 35% decrease in the mean arterial blood pressure. Intraoperative bradycardia was defined as a heart rate of <60 beats/min for >5 minutes. A logistic regression model was developed for predicting intraoperative hypotension or bradycardia with bootstrap validation. Model performance was assessed using area under the receiver operating curves and Hosmer-Lemeshow tests.

RESULTS

A total of 127 patients developed hypotension or bradycardia. The average age of participants was 67.6 ± 11.3 years, and 59.1% underwent major surgery. A final 5-item score was developed, including preoperative Heart rate (<60 beats/min), preoperative hypotension (<110/60 mm Hg), Elderly age (>65 years), preoperative renin-Angiotensin blockade (angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, or beta-blockers), Revised cardiac risk index (≥3 points), and Type of surgery (major surgery), entitled the "HEART" score. The HEART score was moderately predictive of intraoperative bradycardia or hypotension (odds ratio, 2.51; 95% confidence interval, 1.79-3.53; C-statistic, 0.75). Maximum points on the HEART score were associated with an increased likelihood ratio for intraoperative bradycardia or hypotension (likelihood ratio, +3.64).

CONCLUSIONS

The 5-point HEART score was predictive of intraoperative hypotension or bradycardia. These findings suggest a role for using the HEART score to better risk-stratify patients preoperatively and may help guide decisions on perioperative management of blood pressure and heart rate-lowering medications and anesthetic agents.

Preoperative renin-angiotensin system inhibitors use linked to reduced acute kidney injury: a systematic review and meta-analysis

BACKGROUND

Previous trials of interventions to prevent acute kidney injury (AKI) have been unsuccessful and additional interventions are needed. Existing reviews of preoperative renin-angiotensin system (RAS) inhibitors have suggested harm. We included more recent studies and conducted this meta-analysis to evaluate the risk of postoperative AKI in patients who received preoperative RAS inhibitors.

METHODS

A literature search was performed using MEDLINE, EMBASE and Cochrane Database of Systematic Reviews from inception through October, 2014. Studies that reported relative risks, odds ratios or hazard ratios comparing the AKI risk in patients who received preoperative RAS inhibitors versus those who did not were included. We performed the prespecified sensitivity analysis including only propensity score-based studies. Mortality risk was evaluated among the studies that reported AKI outcome. Pooled risk ratios (RR) and 95% confidence interval (CI) were calculated using a random-effect, generic inverse variance method.

RESULTS

Twenty-four studies (1 randomized controlled trial and 23 cohort studies) with 102 675 patients were included in the analysis to assess the risk of postoperative AKI and preoperative RAS inhibitors use. The pooled RR of AKI in patients receiving RAS inhibitors was 1.05 (95% CI: 0.92-1.20). The meta-analysis of the RCT and 11 studies with propensity score analysis demonstrated the pooled RR of AKI in patients receiving RAS inhibitors of 0.92 (95% CI: 0.85-0.99). Within the selected studies, preoperative RAS inhibitor therapy was not associated with a significant increase or decrease in mortality (RR: 0.93; 95% CI: 0.80-1.09).

CONCLUSIONS

Our meta-analysis demonstrates an association between preoperative RAS inhibitor treatment and lower incidence of AKI.

Preoperative evaluation and preparation of patients for orthopedic surgery

Orthopedic patients frequently have multiple comorbidities when they present for surgery. This article discusses risk stratification of this population and the preoperative work-up for patients with specific underlying conditions who often require orthopedic procedures. Preoperative strategies to decrease exposure to allogeneic blood and advantages of the Perioperative Surgical Home model in this unique population are discussed.

Hemodynamic instability during anesthesia in an adolescent with Loeys-Dietz syndrome: a case report

We present a case of a 12-year-old male with Loeys-Dietz syndrome (LDS), a rare life-threatening genetic disorder. Multiple manifestations of LDS were present, including easy bruising, aortic root dilatation, multiple areas of vessel tortuosity, and joint laxity. The patient's medications included a beta-blocker and an angiotensin II receptor antagonist for prophylaxis against further aortic root dilatation due to his LDS. He experienced intraoperative hemodynamic instability and became pulseless during an orthopedic procedure, which had to be abandoned. Anesthesia was reattempted 2 days after cessation of the patient's antihypertensive medications and was successful with only minor postoperative hypertension.

Optimal perioperative management of arterial blood pressure

Perioperative blood pressure management is a key factor of patient care for anesthetists, as perioperative hemodynamic instability is associated with cardiovascular complications. Hypertension is an independent predictive factor of cardiac adverse events in noncardiac surgery. Intraoperative hypotension is one of the most encountered factors associated with death related to anesthesia. In the preoperative setting, the majority of antihypertensive medications should be continued until surgery. Only renin-angiotensin system antagonists may be stopped. Hypertension, especially in the case of mild to moderate hypertension, is not a cause for delaying surgery. During the intraoperative period, anesthesia leads to hypotension. Hypotension episodes should be promptly treated by intravenous vasopressors, and according to their etiology. In the postoperative setting, hypertension predominates. Continuation of antihypertensive medications and postoperative care may be insufficient. In these cases, intravenous antihypertensive treatments are used to control blood pressure elevation.

B-type natriuretic peptide-guided therapy for perioperative medicine?

The recent guideline from the European Society of Cardiology and European Society of Anesthesiology recommended the use of B-type natriuretic peptide (BNP) as preoperative testing for high-risk cardiac patients undergoing non-cardiac surgery. In this article, the potential benefits, risks and details for implementing BNP testing in perioperative medicine are discussed. Review of four related lines of research including the use of BNP test for preoperative prognosis, BNP test for screening asymptomatic heart failure, BNP as prognostic test in asymptomatic, non-heart failure patients and using BNP for detecting silent myocardial ischaemia showed converging cut-off levels of BNP for risk stratification. BNP has better OR and relative risk in comparison with Revised Cardiac Risk Index (RCRI) in predicting perioperative cardiac risk. BNP-guided therapy can be low risk based on current evidence on non-surgical patients, including treating asymptomatic patients without heart failure to prevent cardiovascular complications. At present, there is lack of direct evidence supporting perioperative BNP testing. Further research with randomised controlled trials is needed to confirm the benefit of BNP-guided management. Preoperative BNP testing may be considered in patients with RCRI above 0 undergoing intermediate or high-risk surgery. BNP-guided therapy is likely a beneficial addition to perioperative medicine. Its combination with β-blocker titration, RCRI and perioperative cardiovascular monitoring can be a major advance in reducing cardiac risk resulting in a dynamic, individualised optimisation process.

Angiotensin axis blockade, hypotension, and acute kidney injury in elective major orthopedic surgery

BACKGROUND

Patients presenting for surgery with angiotensin axis blockade (AAB) from therapy with either angiotensin-converting enzyme inhibitors or angiotensin receptor blockers experience an increased incidence of perioperative hypotension. Acute kidney injury (AKI) in patients receiving preoperative AAB has been demonstrated after lung, vascular, and cardiac surgery. However, there is little literature evaluating the hypotensive and renal effects of preoperative AAB and major orthopedic surgery.

METHODS

We performed a retrospective chart review of 1154 patients who underwent spinal fusion, total knee arthroplasty, or total hip arthroplasty during the 2010 calendar year in our academic medical center.

RESULTS

A total of 922 patients met inclusion criteria, 343 (37%) received preoperative AAB. Postinduction hypotension (systolic blood pressure ≤80 mm Hg for 5 minutes) was significantly higher in patients receiving AAB when compared to those not so treated (12.2% vs 6.7%; odds ratio [OR]: 1.93, P = 0.005). Of the 922 patients, 798 had documented measurements of both preoperative and postoperative creatinine. Postoperative AKI was significantly higher in patients receiving AAB therapy (8.3% vs 1.7%; OR: 5.40, P < 0.001), remaining significant after adjusting for covariates including hypotension (OR: 2.60, P = 0.042). Developing AKI resulted in a significantly higher mean length of stay (5.76 vs 3.28 days, P < 0.001) but no difference in 2-year mortality.

CONCLUSIONS

Patients undergoing major elective orthopedic surgery who receive preoperative AAB therapy,have an associated increased risk of postinduction hypotension and postoperative acute kidney injury resulting in a greater hospital length of stay.

Association between angiotensin converting enzyme inhibitor or angiotensin receptor blocker use prior to major elective surgery and the risk of acute dialysis

Background

Some studies but not others suggest angiotensin converting enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB) use prior to major surgery associates with a higher risk of postoperative acute kidney injury (AKI) and death.

Methods

We conducted a large population-based retrospective cohort study of patients aged 66 years or older who received major elective surgery in 118 hospitals in Ontario, Canada from 1995 to 2010 (n = 237,208). We grouped the cohort into ACEi/ARB users (n = 101,494) and non-users (n = 135,714) according to whether the patient filled at least one prescription for an ACEi or ARB (or not) in the 120 days prior to surgery. Our study outcomes were acute kidney injury treated with dialysis (AKI-D) within 14 days of surgery and all-cause mortality within 90 days of surgery.

Results

After adjusting for potential confounders, preoperative ACEi/ARB use versus non-use was associated with 17% lower risk of post-operative AKI-D (adjusted relative risk (RR): 0.83; 95% confidence interval (CI): 0.71 to 0.98) and 9% lower risk of all-cause mortality (adjusted RR: 0.91; 95% CI: 0.87 to 0.95). Propensity score matched analyses provided similar results. The association between ACEi/ARB and AKI-D was significantly modified by the presence of preoperative chronic kidney disease (CKD) (P value for interaction < 0.001) with the observed association evident only in patients with CKD (CKD - adjusted RR: 0.62; 95% CI: 0.50 to 0.78 versus No CKD: adjusted RR: 1.00; 95% CI: 0.81 to 1.24).

Conclusions

In this cohort study, preoperative ACEi/ARB use versus non-use was associated with a lower risk of AKI-D, and the association was primarily evident in patients with CKD. Large, multi-centre randomized trials are needed to inform optimal ACEi/ARB use in the peri-operative setting.