January 2025

Synopsis: This is a systematic review looking at the effect of high versus low protein dosage in enteral nutrition on morbidity and mortality. Using a Bayesian hierarchical meta-analytical model, the authors found that patients receiving high protein enteral nutrition experienced a higher probability of increased rates of mortality and infectious complications and poorer quality of life.

Summary: While higher protein delivery in critically ill patients is often thought to improve clinical outcomes, the evidence is limited due to challenges in performing advanced statistical analyses with available data. This systematic review included 4,164 critically ill patients receiving either high-protein (mean: 1.5 ± 0.6 g/kg/day) or low-protein (mean: 0.9 ± 0.4 g/kg/day) enteral nutrition. The primary endpoint was mortality, while secondary outcomes included infectious complications, duration of mechanical ventilation, and quality of life. The Bayesian hierarchical model used in this study generated probability distributions to estimate the treatment effect sizes.

The analysis revealed a 56% probability of increased mortality with high-protein enteral nutrition compared to a 44% probability of reduced mortality. Specifically, the probabilities of a 1%, 2.5%, 5%, and 10% increase in mortality rates were 51.5%, 44.3%, 32.4%, and 10.3%, respectively.

Among 1,371 patients from seven studies reporting infectious complications, high-protein delivery was associated with a 63.7% probability of harm compared to a 36.6% probability of benefit. For the duration of mechanical ventilation, data from 12 studies (n = 3,042 patients) showed minimal effect, with a 1% probability of benefit and 0.3% probability of harm. Quality of life outcomes, assessed in three studies (n = 1,293), showed a striking 88.5% probability of harm versus an 11.5% probability of benefit with higher protein delivery.

These findings suggest a greater likelihood of increased mortality, infectious complications, and poorer quality of life with higher protein intake compared to lower protein intake in critically ill patients. Conversely, there was little evidence of significant clinical impact on the duration of mechanical ventilation.
Limitations of this study include the heterogenous rates of protein delivery used among studies (therefore requiring that the overall groups of high versus low protein content be based on pooled means), and that only a subset of included studies reported on the secondary outcomes above.

Bottom line: Critically ill patients receiving high versus low protein enteral nutrition experienced higher probabilities of increased mortality, infectious complications, and poorer quality of life.

Synopsis: This retrospective analysis using the UK Registry of Endocrine and Thyroid Surgery (UKRETS) database evaluated the relationship between surgeon volume and outcomes in adrenal surgery. The authors found that higher surgeon volume is associated with reduced complication rates, shorter hospital stays, and better overall outcomes, particularly for high-risk adrenal surgeries.

Summary: The surgeon volume-outcome relationship is well-established in several parts of endocrine surgery, in which increasing surgeon volume translates to better patient outcomes, particularly in thyroid and parathyroid surgery. However, there is sparse literature on what makes a “high volume” adrenal surgeon and whether this impacts clinical outcomes.  

This study utilized the UKRETS database, which is a national database of endocrine surgery run by Dendrite Clinical Systems on behalf of the British Association of Endocrine and Thyroid Surgeons (BAETS). Data on thyroid, parathyroid, endocrine pancreatic, and adrenal surgery are recorded voluntarily in UKRETS by BAETS members. For this study, data were extracted for all adrenal surgeries from 2004 – 2021, which included covariables such as patient age, sex, diagnosis, type of operation, side of pathology, and surgeon volume. Outcome variables collected included complications, length of stay, re-operation, and mortality.  Surgeon volume was calculated by dividing the total number of adrenal operations recorded by individual surgeons by the number of calendar years that they contributed to the database, which was stratified into four categories: below 6 adrenalectomies per year, 6-11.99 surgeries, 12-20 surgeries and over 20 surgeries, a classification system that was based on previous studies. 

A total of 6,174 adrenal surgeries were recorded, with a median of 393 surgeries annually (IQR 183–491). The median surgeon volume was 12 adrenalectomies per year (IQR 5–18). Patients had a median age of 55 years, and most underwent unilateral surgery (95.7%), with bilateral procedures accounting for 4.3%. Minimally invasive techniques were used in 79.9% of cases. Pheochromocytoma (30.8%) was the most common indication for surgery. Overall, complications occurred in 9.4% of cases (418/4464).

In order to evaluate which factors were significantly associated with post-operative complications, a multivariable regression was performed which found adrenal carcinoma (OR 1.64, 95% CI: 1.14 to 2.36) and bilateral surgery (OR 1.66, 95% CI 1.03 to 2.69) were associated with increased risk of complication while surgeon volume (OR 0.98, 0.96 to 0.99) was associated with a slightly decreased risk. Similarly, adrenal cancer and bilateral surgery were associated with a long length of stay whereas surgeon volume was associated with a decreased length of stay. 

The study’s limitations stem primarily from the nature of the database. Data entry in the UKRETS registry is voluntary and unvalidated, which introduces the possibility of significant reporting bias. Additionally, the inclusion of mixed pathologies, encompassing both benign and malignant cases, as well as cases involving concomitant organ resections, may skew the results, as these surgeries are more prone to complications and prolonged hospital stays. Furthermore, the study does not account for surgeon-specific factors such as training, experience, technical variability, or surgical approach, all of which could influence outcomes and complicate the interpretation of the relationship between surgeon volume and patient results.

Bottom line: Higher surgeon volume in adrenal surgery may associated with lower complication rates, shorter hospital stays, and better outcomes. A threshold of at least 12 adrenalectomies per year may define a high-volume surgeon, particularly for complex procedures like bilateral adrenalectomy and adrenal carcinoma. Centralizing care to high-volume centers may further improve patient outcomes.

Synopsis: This is an international multicenter study that looks at the safety and efficacy of physician-modified endografts (PMEGs) used for thoracic and abdominal aortic aneurysms. Overall, the authors found this technique to be safe and effective for elective, symptomatic, and ruptured aortic aneurysms. 

Summary: Since Chuter et al reported the first endovascular repair of a thoracoabdominal aortic aneurysm (TAAA) in 2001, physician-modified endografts (PMEGs) have emerged as a vital treatment option for patients with complex abdominal aortic aneurysms (CAAA) and TAAA who are too high-risk for open surgical repair. While fenestrated and branched custom-made devices (CMD, aka “IDE BEVAR/FEVAR”) remain the gold standard, their limited availability and manufacturing times have led to alternative strategies (parallel grafts, commercial off-the-shelf grafts, PMEGs). Among these options, a well-planned and constructed PMEGs most closely approximate custom devices (CMD) but require significant technical expertise. This study aimed to evaluate the real-world safety and effectiveness of PMEGs in treating TAAAs and CAAAs.

An international multicenter retrospective cohort study including 19 centers (9 USA, 9 Europe, 1 Asia) examined 1,274 consecutive patients from 2007-2022 who received PMEGs for complex aortic aneurysms, which included CAAA (45% of patients; short neck, juxtarenal, pararenal and suprarenal) or TAAA (65% of patients; Extent I-V). Patients were predominantly male (75%) with a median age of 74 years. Most cases were elective (65%), while 25% were performed for symptomatic aneurysms and 10% performed for ruptured aneurysms. The study excluded patients undergoing endovascular aortic arch repairs, iliac modifications, open/hybrid procedures, or any in situ techniques.

Operatively, the majority of PMEG procedures created fenestrated grafts (83% FEVAR), with fewer using branched (3.6% BEVAR) or combination of both (13.4% F/B-EVAR) to preserve visceral arteries. Thirty-day mortality was 5.8% overall but varied by presentation. Major adverse events (MAEs), which was a composite of all-cause mortality, myocardial infarction, stroke, paraplegia, bowel ischemia, respiratory failure, and renal insufficiency occurred in 25% of patients overall. This increased with case urgency - from 23% in elective cases to 28% in symptomatic and 30% in ruptured cases. Higher MAE rates were associated with TAAA (vs CAAA), an urgent procedure, ASA score ≥3, longer operation time, or a technical failure. Encouragingly, complication rates improved from 33% before 2013 to 22% after, suggesting a learning curve and/or better patient selection. Post-2013 cases also showed improved operative times, less blood loss, but an increased PMEG use in emergency cases, though overall outcomes remained similar.

After a median follow-up of 21 months, the 5-year outcomes showed that half of patients needed reintervention (51%: elective 50%, symptomatic 57%, rupture 41.7%), though vessel patency remained excellent at 90%. Overall survival was 55%, with similar rates across all groups (elective 56%, symptomatic 56%, ruptured 49%). Importantly, freedom from aortic-related death was high at 89%. These rates declined gradually from 1-year outcomes of 74%, 97%, 82%, and 93% respectively. While reintervention rates were significant, they matched those of custom-made devices and typically involved minor procedures that did not affect survival. Additionally, while overall survival is low, these were predominantly non-aortic driven (143 cases where cause was known: 25% cardiovascular, 20% cancer, 15% infection, 14% respiratory).

This study had several key limitations: its retrospective design, results coming only from experienced high-volume centers, lack of comparison with other treatments, and incomplete data on surgical techniques. Additionally, the cause of death was unknown in nearly 60% of non-aortic deaths. 

Bottom Line: PMEGs appear to be a safe and effective treatment option for complex aortic aneurysms when performed in experienced centers. While patients require lifetime surveillance and should be prepared for possible reinterventions, the technique offers a viable alternative to the gold standard custom-made devices, particularly in urgent cases or when custom devices are unavailable.