Key Papers from the Most Recent Literature Relevant to Anesthesiologists

Article Selection: Eric C. Sun, M.D., Ph.D. Image: Adobe Stock.

Article Selection: Eric C. Sun, M.D., Ph.D. Image: Adobe Stock.

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Current guidance suggests that GLP-1 (glucagon-like peptide 1) receptor agonists be held preoperatively due to an increased risk of pulmonary complications, but large-scale data examining this risk have been missing. This retrospective observational study of healthcare claims data examined the incidence of postoperative pulmonary complications, defined as aspiration pneumonitis, postoperative respiratory failure, or intensive care unit admission within 0 to 7 postoperative days among 3,502 patients using GLP-1 receptor agonists who underwent emergency surgery and were therefore unlikely to have withheld their medication. A total of 20,177 diabetic patients undergoing emergency surgery who did not use GLP-1 agonists were used as a control group. After adjustment for confounders such as diabetes severity, the incidence of pulmonary complications was 4.0% among the GLP-1 group compared to 3.9% among the controls (odds ratio, 1.03; 95% CI, 0.82 to 1.29; P = 0.80). Study limitations included lack of consideration of specific intubating techniques used (e.g., rapid sequence intubation) and limitation of the cohort to diabetics alone without consideration of patients using the drugs for weight loss.

Take home message: This retrospective analysis of healthcare claims data for patients undergoing emergency surgery comparing outcomes among patients using GLP-1 agonists to a control group of diabetic patients found these drugs were not associated with an increased risk of pulmonary complications.

Article Selection: Beatrice Beck-Schimmer, M.D. Image: Adobe Stock.

Article Selection: Beatrice Beck-Schimmer, M.D. Image: Adobe Stock.

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Limited information is available from only canine or single-arm human observational studies for coronary sinus reduction devices, a mesh percutaneously placed in primary venous drainage of the heart as antianginal therapy. This approach is postulated to redistribute perfusion from more to less well-perfused areas of the myocardium. This double-blind, randomized, placebo-controlled trial in patients with stable coronary artery disease and angina refractory to additional antianginal medication or revascularization options assessed its effect over a 6-month period after implantation. The primary outcome was myocardial blood flow at 6 months in ischemic areas compared to a baseline adenosine-stress perfusion cardiac magnetic resonance scan. The primary symptom outcome was the number of angina episodes reported in a smartphone application (ORBITA-app). Fifty-one patients (86% male; median age, 67 yr [interquartile range, 61 to 74 yr] from six United Kingdom hospitals) were randomly assigned to either coronary sinus reducer implantation (n = 25 with 1 patient not analyzed due to a serious adverse event) or a placebo procedure (n = 26). Although there was no difference in the primary outcome (difference coronary sinus reducer vs. placebo: 0.06 ml · min–1 · g–1 [95% credible interval, 0.09 to 0.20]; Pr(Benefit) = 78.8%), daily angina episodes decreased significantly (odds ratio, 1.40 [95% credible interval, 1.08 to 1.83]; Pr(Benefit) = 99.4%).

Take home message: This placebo-controlled trial of a coronary sinus reduction device failed to demonstrate an improvement in myocardial perfusion in ischemic regions in patients with refractory angina at 6 months despite a significant reduction in anginal symptoms in the treated group.

Article Selection: Charles Emala, M.D. Image: Adobe Stock.

Article Selection: Charles Emala, M.D. Image: Adobe Stock.

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Acute kidney injury after hypoperfusion is common and it has a higher occurrence in older patients but has not previously been clearly associated with genetic risk factors. Clonal hematopoiesis of indeterminate potential is a well-recognized phenomenon of aging that results from the clonal expansion of hematopoietic stem cells that have previously acquired mutations. Several of these mutated genes (DNMT3A, TET2, JAK2) have been associated with increased mortality in cardiovascular, pulmonary, and liver diseases and are associated with enhanced and sustained inflammatory organ injury. In the current study, these gene mutations associated with clonal hematopoiesis of indeterminate potential occurred in 3.4% of samples in the United Kingdom BioBank, were increased with age, and were associated with a 34% increased risk of acute kidney injury. Furthermore, clonal hematopoiesis of indeterminate potential was associated with a 20% increased risk of acute kidney injury in a meta-analysis of two prospective cohort studies, the Atherosclerosis Risk in Communities (ARIC) and the Cardiovascular Health Study (CHS). Clonal hematopoiesis of indeterminate potential was also associated with impaired recovery from acute kidney injury in two additional human cohort studies. In mice, bone marrow transplants from mice with mutations in TET2 or Jak2 demonstrated enhanced blood urea nitrogen and creatinine after ischemia reperfusion or urethral obstruction injuries with enhanced markers of inflammation and fibrosis attributed to macrophages that persisted chronically.

Take home message: Clonal hematopoiesis of indeterminate potential is a genetic mutation process associated with aging that yields macrophages that increase the risk of acute kidney injury and impaired recovery due to chronic inflammatory and fibrotic kidney changes. Therapeutic targeting of the inflammasome or downstream mediators of these genetic pathways may be a modifiable risk factor to limit progression to chronic kidney disease.

Article Selection: Ru-Rong Ji, Ph.D. Image: Adobe Stock.

Article Selection: Ru-Rong Ji, Ph.D. Image: Adobe Stock.

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Rotator cuff injuries affect more than 17 million individuals in the United States, leading to approximately 500,000 surgeries each year. These surgeries, which often involve the removal of the subacromial bursa, synovial-like tissue located between the rotator cuff and acromion, have high failure rates. This study demonstrates that the subacromial bursa plays an active role in the resolution of inflammatory and healing processes after tendon injury. Several experiments using clinical biopsies from nine patients with rotator cuff injury as well as a rodent model revealed that the bursa responds to tendon injuries by up-regulating genes linked to inflammation and healing (Cox2, IL6, Tgfb1). In rats, removing the bursa hindered resolution of inflammation and negatively affected the adjacent infraspinatus tendon and humeral head. Targeted treatment with dexamethasone in rats demonstrated potential therapeutic benefits by control of inflammation. However, limitations due to variability in patient samples suggest a need for more focused studies to develop tailored treatment strategies for rotator cuff injuries.

Take home message: After rotator cuff injury, the subacromial bursa plays a protective role, and targeting it with dexamethasone could help regulate inflammatory response in injured rotator cuff. Its routine removal during shoulder surgery should be reconsidered.

Article Selection: Martin J. London, M.D. Image: Adobe Stock.

Article Selection: Martin J. London, M.D. Image: Adobe Stock.

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The efficacy of β-blocker use after myocardial infarction for secondary prevention is controversial. This parallel-group, open-label trial (September 2017 to May 2023; 45 centers in Sweden, Estonia, and New Zealand) of patients with acute myocardial infarction (obstructive disease on coronary angiography; left ventricular ejection fraction of at least 50%) randomized 5,020 patients to either long-term treatment with a β blocker (100 mg metoprolol daily or at least 5 mg bisoprolol daily) (N = 2,508) or no β-blocker treatment (N = 2,512). The primary endpoint was a composite of death from any cause or new myocardial infarction. Cohort characteristics included median age 65 yr, 22.5% female, and 35.2% ST-segment elevation myocardial infarction. The median follow-up was 3.5 yr (interquartile range, 2.2 to 4.7 yr). There was no difference in the primary outcome between groups (7.9% β blocker vs. 8.3% without; hazard ratio, 0.96; 95% CI, 0.79 to 1.16; P = 0.64). As well, no differences were noted in secondary endpoints (death from any cause, 3.9% vs. 4.1%; death from cardiovascular causes, 1.5% vs. 1.3%; myocardial infarction, 4.5% vs. 4.7%; hospitalization for atrial fibrillation, 1.1% vs. 1.4%; and hospitalization for heart failure, 0.8% vs. 0.9%). No differences in a variety of safety endpoints were noted.

Take home message: This large, parallel-group, randomized trial of primarily European patients with predominantly non–ST-segment elevation myocardial infarction and left ventricular ejection fraction greater than or equal to 50% demonstrated no difference in death or new myocardial infarction with or without the use of β blockers for secondary prevention over a 3.5-yr median follow-up period.

Article Selection: Jamie Sleigh, M.D. Image: J. P. Rathmell.

Article Selection: Jamie Sleigh, M.D. Image: J. P. Rathmell.

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Ideally, neurosurgeons would be able to resect all pathologic brain tissue without disrupting any of the surrounding healthy tissue. However, existing methods to identify the pathologic tissue boundaries are not very accurate. This study examined the potential to use a flexible panel of electrodes to display the intraoperative spatial patterns of the underlying cortical electrical activity in real time. The panel consisted of ultrathin platinum nanorod grids (1,024 channels, each 30-µm diameter), made of brain-conformal parylene C, and coupled to gallium nitride light-emitting diodes (grids of 1,024 or 2,048, each 220- or 100-µm diameter). In an anesthetized pig model, the coverage was 32 × 32mm (1-mm resolution). It was possible to demonstrate anatomic maps of somatosensory-evoked potentials. Phase reversal of these could be used to accurately map the boundary between the primary motor and somatosensory brain regions. The microdisplay could also reliably detect high-frequency (gamma) electroencephalogram (EEG) responses to air-puff sensory stimuli; the response to the standard Ojemann stimuli; and local neurotoxin-induced epileptiform discharges, which corresponded well with subsequent offline EEG automatic seizure-detection analysis. In a rat model, the coverage was 5 × 5mm. The 0.15-mm resolution was able to display high-resolution pathologic activity down to the level of submillimeter-scale cortical columns.

Take home message: The high-resolution and real-time feedback of this EEG-microdisplay system enables the visualization of cortical dynamics, which could be used to make intraoperative brain mapping more precise.

Article Selection: BobbieJean Sweitzer, M.D. Image: Adobe Stock.

Article Selection: BobbieJean Sweitzer, M.D. Image: Adobe Stock.

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Approximately 40% of heart transplant recipients are from minoritized racial and ethnic groups, and approximately 25% of heart recipients are women. Black persons and women are less likely to be listed for heart transplantation. The matching process follows an algorithm, but decisions to accept offers are more nuanced and subjective. Black men and women are less likely than White men and women to receive a heart transplant after listing. Using the United Network for Organ Sharing, this cohort study identified organ acceptance with each offer for U.S. Black and non-Hispanic White adults listed for heart transplantation from October 18, 2018, to March 31, 2023. There were 14,890 candidates listed for heart transplantation; 30.9% Black, 69.1% White, 73.6% men, and 26.4% women for 159,177 offers from 13,760 donors. Offer acceptance was highest for White women followed by Black women, White men, and Black men (P < 0.001). Odds of acceptance were less for Blacks than for Whites for first offers (odds ratio, 0.76; 95% CI, 0.69 to 0.84) through the 16th offer. Odds of acceptance were higher for women than for men for first offers (odds ratio, 1.53; 95% CI, 1.39 to 1.68) through the sixth offer and were lower for offers 10 through 31.

Take home message: Transplant center teams consistently accepted heart offers at a lower rate for Black candidates than for White candidates of the same sex and at higher rates for women than for men.

Article Selection: William G. Tharp, M.D., Ph.D. Image: Adobe Stock.

Article Selection: William G. Tharp, M.D., Ph.D. Image: Adobe Stock.

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Cardiovascular disease is a leading cause of death worldwide. Risk prediction tools facilitate interventions, but currently used prediction algorithms may underestimate risk in emerging high-risk populations. This study analyzed two established research databases containing anonymized health data from more than 16 million patients, aged 18 to 84 yr, receiving routine care through the United Kingdom’s National Health Service since 1989. The primary outcome was incidence of cardiovascular disease defined as fatal or nonfatal ischemic heart disease, cerebrovascular disease, or transient ischemic attack. The new algorithm (QR4) estimates the 10-yr risk using cause-specific proportional hazard models derived and validated using data from 9.98 and 6.79 million patients, respectively. The QR4, adjusted for age and body mass index, identified seven new predictors in men and women: chronic obstructive pulmonary disease (pooled hazard ratio 1.38 [95% CI, 1.33 to 1.42]), learning disability (1.25 [1.16 to 1.34]), Down syndrome (2.59 [2.10 to 3.07]), brain cancers (5.05 [3.16 to 6.93]), blood cancers (2.08 [1.82 to 2.34]), lung cancers (1.67 [1.43 to 1.90]), and oral cancers (1.51 [1.34 to 1.68]), in addition to two new predictors in women: pre-eclampsia (1.56 [1.36 to 1.78]) and postpartum depression (1.18 [1.11 to 1.26]).

Take home message: The QR4 algorithm yields improved cardiovascular risk prediction in the United Kingdom and identifies novel high-risk patient populations.

Article Selection: Michael Zaugg, M.D., M.B.A. Image: J. P. Rathmell.

Article Selection: Michael Zaugg, M.D., M.B.A. Image: J. P. Rathmell.

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Surgical site infection affects 1 in 30 procedures and represents the costliest complication of surgery. However, it is elusive whether surgical site infections are caused by exogenous sources from nosocomial reservoirs or by endogenous reservoirs of colonizing microbiota carried by the patient. With the use of instrumented spine surgery as a model of clean skin incision, preoperative microbiomes from different anatomic sites and microbiomes from postoperative surgical site infections were determined in a cohort of 204 patients combining multiple forms of genomic analysis. Identity of bacterial species and anatomic distribution of preoperative strains were correlated with identity and antimicrobial resistance of the pathogens of the 14 (6.8%) occurring surgical site infections. There was a significant anatomic correlation between the preoperative microbiome on the back skin and the microbiology of postoperative surgical site infections (Staphylococci correlated with cephalad skin, Escherichia and Enterobacter with lumbosacral skin). Strains causing postoperative wound infections were present in the preoperative microbiome and their preoperative antibiotic resistance profile correlated with prophylaxis-resistant postoperative infections. A total of 86% of surgical site infections originated endogenously from preoperative strains, and 59% were resistant to the prophylactic antibiotic administered during surgery. Molecular analysis of all spine surgical site infections occurring within the shared perioperative environment during the study period showed no evidence of exogenous infections from shared nosocomial reservoirs.

Take home message: While sterility of the physical environment remains the cornerstone of modern wound infection prevention, this study emphasizes the need for surgical site infection prevention strategy tailored to the patient-specific preoperative microbiome and its resistance to antibiotics.