Introduction

Spinal cord stimulation (SCS), an FDA-approved therapy for chronic pain, uses paresthesia (low frequency SCS (LF-SCS)) or paresthesia-free (such as high-frequency SCS (HF-SCS)) systems, providing analgesia through partially-elucidated mechanisms, with recent studies indicating a sexual dimorphism in pain pathogenesis (Bretherton et al., Neuromodulation, 2021; Paller et al., Pain Med 10:289-299, 2009; Slyer et al., Neuromodulation, 2019; Van Buyten et al., Neuromodulation 20:642-649, 2017; Mekhail et al., Pain Pract, 2021). We aim to evaluate SCS therapy sex effects based on paradigm, utilizing visual analog scores (VAS), perceived pain reduction (PPR), and opioid use.

Methods

A retrospective cohort study of SCS patients implanted between 2004 and 2020 (n = 237) was conducted. Descriptive statistics and linear mixed methods analyses were used.

Results

HF-SCS (10 kHz) was implanted in 94 patients (40 females, 54 males), and LF-SCS in 143 (70 females, 73 males). At 3 months and 6 months, HF-SCS (p < 0.001) and LF-SCS (p < 0.005) had lower VAS scores compared to baseline (p < 0.005), with no differences across groups. PPR improved in both post-implantation (p < 0.006) and at 3 months (p < 0.004 respectively), compared to baseline persisting to 6 (p < 0.003) and 12 months (p < 0.01) for HF-SCS, with significantly better PPR for HF-SCS at 3 (p < 0.008) and 6 (p < 0.001) months compared to LF-SCS. There were no differences in opioid use from baseline for either modality; however LF-SCS patients used more opioids at every time point (p < 0.05) compared to HF-SCS. VAS was improved for all modalities in both sexes at 3 months (p = 0.001), which persisted to 6 months (p < 0.05) for HF-SCS males and females, and LF-SCS females. Female HF-SCS had improved PPR at 3 (p = 0.016) and 6 (p = 0.022) months compared to baseline, and at 6 (p = 0.004) months compared to LF-SCS. Male HF-SCS and LF-SCS had improved PPR post-implantation (p < 0.05) and at 3 months (p < 0.05), with HF-SCS having greater benefit at 3 (p < 0.05) and 6 (p < 0.05) months. LF-SCS males but not females used less opioids at 6 months (p = 0.017) compared to baseline; however this effect did not persist. On linear mixed model analyses, including age, sex and stimulator type, VAS decreased with age, at each timepoint, and had a trend towards increasing with female sex, while PPR increased at 3 and 6 months and lastly HF-SCS was associated with decreased opioid use.

Discussion

PPR at 3 and 6 months improved to a greater extent in HF-SCS. HF-SCS females had improved PPR at 3 and 6 months, and only LF-SCS males used less opioids at 6 months, potentially indicating sex-based pathway. Future studies should further elucidate differences in sex-based pathways and identify optimal SCS opioid-sparing paradigms for chronic pain patients.

Background

Recent studies have shown a trend supporting endovascular revascularization (ER) in the treatment of chronic mesenteric ischemia (CMI). However, few studies have compared the cost effectiveness of ER and open revascularization (OR) for this indication. The purpose of this study is to conduct a cost-effectiveness analysis comparing open versus ER for CMI.

Methods

We built a Markov model with Monte Carlo microsimulation using transition probabilities and utilities from existing literature for CMI patients undergoing OR versus ER. Costs were derived from the hospital perspective using the 2020 Medicare Physician Fee Schedule. The model randomized 20,000 patients to either OR or ER and allowed for 1 subsequent reintervention with 3 other intervening health states: alive, alive with complications, and dead. Quality-adjusted life years (QALYs), costs, and incremental cost-effectiveness ratio (ICER) were analyzed over a 5-year period. One-way sensitivity and probabilistic sensitivity analyses were conducted to study the impact of parameter variability on cost effectiveness.

Results

OR cost $4,532 for 1.03 QALYs while ER cost $5,092 for 1.21 QALYs, leading to an ICER of $3,037 per QALY gained in the ER arm. This ICER was less than our willingness to pay threshold of $100,000. Sensitivity analysis demonstrated that our model was most sensitive to costs, mortality, and patency rates after OR and ER. Probabilistic sensitivity analysis demonstrated ER would be considered cost effective 99% of iterations.

Conclusions

This study found that while 5-year costs for ER were greater than OR, ER afforded greater QALYs than OR. Although ER is associated with lower long-term patency and higher rates of reintervention, it appears to be more cost effective than OR for the treatment of CMI.

Background

Watch and wait (WW) protocols have gained increasing popularity for patients diagnosed with locally advanced rectal cancer and presumed complete clinical response after neoadjuvant chemoradiation. While studies have demonstrated comparable survival and recurrence rates between WW and radical surgery, the decision to undergo surgery has significant effects on patient quality of life. We sought to conduct a cost-effectiveness analysis comparing WW with abdominoperineal resection (APR) and low anterior resection (LAR) among patients with stage II/III rectal cancer.

Methods

In this comparative-effectiveness study, we built Markov microsimulation models to simulate disease progression, death, costs, and quality-adjusted life-years (QALYs) for WW or APR/LAR. We assessed cost effectiveness using the incremental cost-effectiveness ratio (ICER), with ICERs under $100,000/QALY considered cost effective. Probabilities of disease progression, death, and health utilities were extracted from published, peer-reviewed literature. We assessed costs from the payer perspective.

Results

WW dominated both LAR and APR at a willingness to pay (WTP) threshold of $100,000. Our model was most sensitive to rates of distant recurrence and regrowth after WW. Probabilistic sensitivity analysis demonstrated that WW was the dominant strategy over both APR and LAR over 100% of iterations across a range of WTP thresholds from $0-250,000.

Conclusions

Our study suggests WW could reduce overall costs and increase effectiveness compared with either LAR or APR. Additional clinical research is needed to confirm the clinical efficacy and cost effectiveness of WW compared with surgery in rectal cancer.

Objective

The current recommendations are to perform carotid endarterectomy within 2 weeks of symptoms for maximum long-term stroke prevention, although urgent carotid endarterectomy within 48 hours has been associated with increased perioperative stroke. With the development and rapid adoption of transcarotid artery revascularization (TCAR), we decided to study the effect of timing on the outcomes after TCAR.

Methods

The Vascular Quality Initiative database was searched for symptomatic patients who had undergone TCAR from September 2016 to November 2019. These patients were stratified by the interval to TCAR after symptom onset: urgent, within 48 hours; early, 3 to 14 days; and late, >14 days. The primary outcome was the in-hospital rate of combined stroke and death (stroke/death), evaluated using logistic regression analysis. The secondary outcome was the 1-year rate of recurrent ipsilateral stroke and mortality, evaluated using Kaplan-Meier survival analysis.

Results

A total of 2608 symptomatic patients who had undergone TCAR were included. The timing was urgent for 144 patients (5.52%), early for 928 patients (35.58%), and late for 1536 patients (58.90%). Patients undergoing urgent intervention had an increased risk of in-hospital stroke/death, which was driven primarily by an increased risk of stroke. No differences were seen for in-hospital death. On adjusted analysis, urgent intervention resulted in a threefold increased risk of stroke (odds ratio [OR], 2.8; 95% confidence interval [CI], 1.3-6.2; P = .01) and a threefold increased risk of stroke/death (OR, 2.9; 95% CI, 1.3-6.4; P = .01) compared with late intervention. Patients undergoing early intervention had comparable risks of stroke (OR, 1.3; 95% CI, 0.7-2.3; P = .40) and stroke/death (OR, 1.2; 95% CI, 0.7-2.1; P = .48) compared with late intervention. On subset analysis, the type of presenting symptoms was an effect modifier. Patients presenting with stroke and those presenting with transient ischemic attack or amaurosis fugax both had an increased risk of stroke/death when undergoing urgent compared with late TCAR (OR, 2.7; 95% CI, 1.1-6.6; P = .04; and OR, 4.1; 95% CI, 1.1-15.0; P = .03, respectively). However only patients presenting with transient ischemic attack or amaurosis fugax had experienced an increased risk of stroke with urgent compared with late TCAR (OR, 5.0; 95% CI, 1.4-17.5; P < .01). At 1 year of follow-up, no differences were seen in the incidence of recurrent ipsilateral stroke (urgent, 0.7%; early, 0.2%; late, 0.1%; P = .13) or postdischarge mortality (urgent, 0.7%; early, 1.6%; late, 1.8%; P = .71).

Conclusions

We found that TCAR had a reduced incidence of stroke when performed 48 hours after symptom onset. Urgent TCAR within 48 hours of the onset of stroke was associated with a threefold increased risk of in-hospital stroke/death, with no added benefit for ≤1 year after intervention. Further studies are needed on long-term outcomes of TCAR stratified by the timing of the procedure.

Background

Poststent ballooning/angioplasty (post-SB) have been shown to increase the risk of stroke risk after transfemoral carotid artery stenting. With the advancement of transcarotid artery revascularization (TCAR) with dynamic cerebral blood flow reversal, we aimed to study the impact of post-SB during TCAR.

Methods

Patients undergoing TCAR in the Vascular Quality Initiative between September 2016 and May 2019 were included and were divided into three groups: those who received prestent deployment angioplasty only (pre-SB, reference group), those who received poststent deployment ballooning only (post-SB), and those who received both prestent and poststent deployment ballooning (prepost-SB). Patients who did not receive any angioplasty during their procedure (n = 367 [6.7%]) were excluded because these represent a different group of patients with less complex lesions than those requiring angioplasty. Primary outcome was in-hospital stroke or death. Analysis was performed using univariable and multivariable logistic regression models.

Results

Of 5161 patients undergoing TCAR, 34.7% had pre-SB only, 25% had post-SB only, and 40.3% had both (prepost-SB). No differences in the rates of in-hospital and 30-day stroke, death, and stroke/death were observed among the three groups; in-hospital stroke/death in the pre-SB group was 1.4% (n = 25), post-SB 1.2% (n = 16), and prepost-SB 1.4% (n = 29; P = .92). However, patients undergoing post-SB and prepost-SB had higher rates of in-hospital transient ischemic attacks (TIA) (post-SB, 0.9%; prepost-SB, 1% vs pre-SB, 0.2%, P < .01) and postprocedural hypotension (16.6% and 16.8% vs 13.1%, respectively; P < .001). Post-SB also had longer operative times, as well as flow reversal and fluoroscopy times. On multivariable analysis, no association was seen between post-SB and the primary outcome of in-hospital stroke/death (post-SB odds ratio [OR], 0.88; 95% confidence interval [CI], 0.44-1.73; prepost-SB OR, 0.98; 95% CI, 0.57-1.70). Similarly, no significant differences were noted in terms of postprocedural hemodynamic instability and 30-day outcomes. However, post-SB and prepost-SB were associated with four times the odds of in-hospital TIA compared with pre-SB alone (post-SB OR, 4.24 [95% CI, 1.51-11.8]; prepost-SB OR, 4.76 [95% CI, 1.53-14.79]; P = .01). Symptomatic patients had higher rates of in-hospital stroke/death compared with their asymptomatic counterparts; however, there was no significant interaction between symptomatic status and ballooning in predicting the primary outcome.

Conclusions

Post-SB was used in 65.3% of TCAR patients. This maneuver seems to be safe without an increase in the odds of postoperative in-hospital stroke/death. However, the increased rates of TIA associated with post-SB requires further investigation.

Background and purpose

Advancements in carotid revascularization have produced promising outcomes in patients with symptomatic carotid artery stenosis. However, the optimal timing of revascularization procedures after symptomatic presentation remains unclear. The purpose of this study is to compare in-hospital outcomes of transcarotid artery revascularization (TCAR), transfemoral carotid stenting (TFCAS), or carotid endarterectomy (CEA) performed within different time intervals after most recent symptoms.

Methods

This is a retrospective cohort study of United States patients in the vascular quality initiative. All carotid revascularizations performed for symptomatic carotid artery stenosis between September 2016 and November 2019 were included. Procedures were categorized as urgent (0-2 days after most recent symptom), early (3-14 days), or late (15-180 days). The primary outcome of interest was in-hospital stroke and death. Secondary outcomes include in-hospital stroke, death, and transient ischemic attacks. Multivariable logistic regression was used to compare outcomes.

Results

A total of 18 643 revascularizations were included: 2006 (10.8%) urgent, 7423 (39.8%) early, and 9214 (49.42%) late. Patients with TFCAS had the highest rates of stroke/death at all timing cohorts (urgent: 4.0% CEA, 6.9% TFCAS, 6.5% TCAR, P=0.018; early: 2.5% CEA, 3.8% TFCAS, 2.9% TCAR, P=0.054; late: 1.6% CEA, 2.8% TFCAS, 2.3% TCAR, P=0.003). TFCAS also had increased odds of in-hospital stroke/death compared with CEA in all 3 groups (urgent adjusted odds ratio [aOR], 1.7 [95% CI, 1.0-2.9] P=0.03; early aOR, 1.6 [95% CI, 1.1-2.4] P=0.01; and late aOR, 1.9 [95% CI, 1.2-3.0] P=0.01). TCAR and CEA had comparable odds of in-hospital stroke/death in all 3 groups (urgent aOR, 1.9 [95% CI, 0.9-4], P=0.10), (early aOR, 1.1 [95% CI, 0.7-1.7], P=0.66), (late aOR, 1.5 [95% CI, 0.9-2.3], P=0.08).

Conclusions

CEA remains the safest method of revascularization within the urgent period. Among revascularization performed outside of the 48 hours, TCAR and CEA have comparable outcomes.

Purpose

Colorectal cancer (CRC) is a leading cause of international morbidity and is the second highest cause of cancer-related mortality in the world. The purpose of this study was to investigate the relationship between international health care spending on CRC mortality over time.

Methods

This is a retrospective study using a publicly available data from the WHO Global Health Observatory database. General estimating equations were used to analyze the relationship between total health care expenditure per capita (THEpc) and CRC mortality at the country level. The primary predictors of interest were quartiles of THEpc. Other exposure variables included gross domestic product per capita (GDPpc), smoking (% of adult population smoking), physician density (per 10,000), and time.

Results

Mortality decreased significantly from 2000 to 2016 (coefficient [95% CI], -2.2 [-3.3 to -1.1]; P < .001). THEpc, GDPpc, time, and percentage of adult population smoking were significant predictors of CRC mortality. Patients in the top two quartiles of THEpc had 3% higher rates of CRC mortality compared with countries in Q1 THEpc (Q3: 3.4 [1.9-4.8], P < .001; Q4: 3.2 [1.4-5.0], P = .001). Similar trends were seen in GDPpc (Q4: 3.2 [1.4-5.0], P = .001; Q3: 3.4 [1.9-4.8], P < .001; Q2: 1.7 [0.7-2.6], P < .001; Q1: reference).

Conclusion

Overall, mortality decreased significantly over the study period. Countries with higher health expenditures and higher gross domestic products experienced higher rates of CRC mortality. Further research will be necessary to determine the cause for this, but we postulate that it may be a result of more robust diagnostic and follow-up methods in countries with more resources.

Well-established in the field of bioelectronic medicine, Spinal Cord Stimulation (SCS) offers an implantable, non-pharmacologic treatment for patients with intractable chronic pain conditions. Chronic pain is a widely heterogenous syndrome with regard to both pathophysiology and the resultant phenotype. Despite advances in our understanding of SCS-mediated antinociception, there still exists limited evidence clarifying the pathways recruited when patterned electric pulses are applied to the epidural space. The rapid clinical implementation of novel SCS methods including burst, high frequency and dorsal root ganglion SCS has provided the clinician with multiple options to treat refractory chronic pain. While compelling evidence for safety and efficacy exists in support of these novel paradigms, our understanding of their mechanisms of action (MOA) dramatically lags behind clinical data. In this review, we reconstruct the available basic science and clinical literature that offers support for mechanisms of both paresthesia spinal cord stimulation (P-SCS) and paresthesia-free spinal cord stimulation (PF-SCS). While P-SCS has been heavily examined since its inception, PF-SCS paradigms have recently been clinically approved with the support of limited preclinical research. Thus, wide knowledge gaps exist between their clinical efficacy and MOA. To close this gap, many rich investigative avenues for both P-SCS and PF-SCS are underway, which will further open the door for paradigm optimization, adjunctive therapies and new indications for SCS. As our understanding of these mechanisms evolves, clinicians will be empowered with the possibility of improving patient care using SCS to selectively target specific pathophysiological processes in chronic pain.

Purpose

Gastrointestinal stromal tumors (GIST) commonly arise in different regions of the stomach and are driven by various mutations (most often in KIT, PDGFRA, and SDHx). We hypothesized that the anatomic location of gastric GIST is associated with unique genomic profiles and distinct driver mutations.

Experimental design

We compared KIT versus non-KIT status with tumor location within the National Cancer Database (NCDB) for 2,418 patients with primary gastric GIST. Additionally, we compiled an international cohort (TransAtlantic GIST Collaborative, TAGC) of 236 patients and reviewed sequencing results, cross-sectional imaging, and operative reports. Subgroup analyses were performed for tumors located proximally versus distally. Risk factors for KIT versus non-KIT tumors were identified using multivariate regression analysis. A random forest machine learning model was then developed to determine feature importance.

Results

Within the NCDB cohort, non-KIT mutants dominated distal tumor locations (P < 0.03). Proximal GIST were almost exclusively KIT mutant (96%) in the TAGC cohort, whereas 100% of PDGFRA and SDH-mutant GIST occurred in the distal stomach. On multivariate regression analysis, tumor location was associated with KIT versus non-KIT mutations. Using random forest machine learning analysis, stomach location was the most important feature for predicting mutation status.

Conclusions

We provide the first evidence that the mutational landscape of gastric GIST is related to tumor location. Proximal gastric GIST are overwhelmingly KIT mutant, irrespective of morphology or age, whereas distal tumors display non-KIT genomic diversity. Anatomic location of gastric GIST may therefore provide immediate guidance for clinical treatment decisions and selective confirmatory genomic testing when resources are limited.