Volume Cut Points Research Articles

Distinct neural signatures of pulvinar in C9orf72 amyotrophic lateral sclerosis mutation carriers and noncarriers.

Thalamic alterations have been reported as a major feature in presymptomatic and symptomatic patients carrying the C9orf72 mutation across the frontotemporal dementia-amyotrophic lateral sclerosis (ALS) spectrum. Specifically, the pulvinar, a high-order thalamic nucleus and timekeeper for large-scale cortical networks, has been hypothesized to be involved in C9orf72-related neurodegenerative diseases. We investigated whether pulvinar volume can be useful for differential diagnosis in ALS C9orf72 mutation carriers and noncarriers and how underlying functional connectivity changes affect this region. We studied 19 ALS C9orf72 mutation carriers (ALSC9+) accurately matched with wild-type ALS (ALSC9-) and ALS mimic (ALSmimic) patients using structural and resting-state functional magnetic resonance imaging data. Pulvinar volume was computed using automatic segmentation. Seed-to-voxel functional connectivity analyses were performed using seeds from a pulvinar functional parcellation. Pulvinar structural integrity had high discriminative values for ALSC9+ patients compared to ALSmimic (area under the curve [AUC] = 0.86) and ALSC9- (AUC = 0.77) patients, yielding a volume cutpoint of approximately 0.23%. Compared to ALSmimic, ALSC9- showed increased anterior, inferior, and lateral pulvinar connections with bilateral occipital-temporal-parietal regions, whereas ALSC9+ showed no differences. ALSC9+ patients when compared to ALSC9- patients showed reduced pulvinar-occipital connectivity for anterior and inferior pulvinar seeds. Pulvinar volume could be a differential biomarker closely related to the C9orf72 mutation. A pulvinar-cortical circuit dysfunction might play a critical role in disease progression and development, in both the genetic phenotype and ALS wild-type patients.

Defining Volume Targets for Regionalization of Pancreaticoduodenectomy, Esophagectomy, and Major Lung Resection Centers to Improve Oncologic and Surgical Outcomes.

Performance of complex cancer surgeries at high-volume (HV) centers has been shown to reduce operative mortality. However, the case volume threshold that should be used to define HV centers is unknown. In this study, we determined thresholds to define HV pancreaticoduodenectomy, esophagectomy, and major lung resection centers based on clinical parameters. Then, we assessed the association of hospital volume with oncologic outcomes and overall survival. We identified adult NCDB patients undergoing pancreaticoduodenectomy, esophagectomy, and major lung resections between 2004 and 2015. Multivariable models with restricted cubic splines were built to predict 5-year overall survival for each surgery group according to average yearly case volume, adjusting for demographic and clinicopathologic factors. The change point procedure was then used to identify volume cut-points for each surgery type. We identified the following thresholds to define HV status: 25 cases/year for pancreaticoduodenectomy; 18 cases/year for esophagectomy; and 54 cases/year for major lung resections. For all surgery types, treatment at a HV center was associated with an increased likelihood of R0 resection and adequate lymph node evaluation. HV centers had significantly decreased 30- and 90-day, postoperative mortality after adjusting for age, sex, race, comorbidities, histology, and stage. An overall survival benefit also was observed for patients undergoing resections at HV centers. Using novel methodology, our study identified volume thresholds for HV pancreaticoduodenectomy, esophagectomy, and major lung resection centers that were associated with improved oncologic outcomes and overall survival. These definitions of HV centers should be considered when evaluating regionalization of complex cancer care.

Guideline Compliant Minimum Asymptomatic Carotid Endarterectomy Surgeon and Hospital Volume Cutoffs

There is a known association between volume and outcomes after carotid endarterectomy (CEA). A recent analysis suggested rates of stroke and death do not significantly reduce after a surgeon volume cutoff of 20 CEAs per year. However, these results would severely limit access. The objective here is to identify a lower optimal cutpoint for surgeon and hospital volume for asymptomatic CEA. We evaluated asymptomatic CEA patients using The New York Statewide Planning and Research Cooperative System database from 2000-2014. The relationship of 3-year averaged volumes for surgeons and hospitals to 30-day stroke were assessed using multiple logistic regression and included both hospital and surgeon volume in all analyses. Optimized cutpoints were the lowest significant volume cutoff that minimized the adjusted odds ratio of stroke. We studied 32,549 CEAs performed by 271 surgeons in 136 centers by vascular surgeons. The median surgeon volume was 26.3(IQR:12.3-51.7) and the median hospital volume was 67(IQR:36.3-119.3). The surgeon volume cutpoint was 3 and the hospital volume cutpoint was 6 cases per year. There were 756(2.3%) procedures performed by surgeons with a volume <3 and 560 (1.7%) procedures performed by hospitals with a volume <6. Perioperative stroke and death rates were 2.0% (95%CI:1.8-2.1) and 3.8% (95%CI:2.6-5.5) for an average yearly surgeon volume ≥3 and <3 (p=0.070), respectively. The combined Stroke and death rate was 2.0% (95%CI:1.8-2.1) and 4.8% (95%CI:3.2-7.0) for an average yearly center volume ≥6 and <6 (p=0.007), respectively. A combined surgeon and hospital volume variable also predicted outcomes and low volume procedures did not meet previously proposed AHA and SVS quality measures. These data demonstrate an improvement in outcomes at a lower volume threshold than previously reported. These modest cutoff values should be used for asymptomatic CEA volume guideline formation and for future studies, after accounting for the impact of other important factors that may be driving volume-outcomes relationships in asymptomatic CEA.

Systemic anticancer treatment in the Netherlands: Few hospitals treat many patients, many hospitals treat few patients

IntroductionThe correlation between patient volume and clinical outcomes is well known for various oncological treatments, especially in the surgical field. The current level of centralisation of systemic treatment of (hemato-)oncology indications in Dutch hospitals is unknown. ObjectivesThe aim of this study was to gain insight in patient volumes per hospital of patients treated with systemic anticancer treatment in the Netherlands. MethodsNational claims data (Vektis) of all 73 Dutch hospitals that provide systemic anticancer medication in the Netherlands for the time period 2019 were used. The distribution of volumes of patients treated with anticancer medication for 38 different haematological or oncological indications was analysed. Hospitals were categorized into academic/specialised, general, and top clinical. Two volume cut off points (10 and 30 patients) were used to identify hospitals treating relatively few patients with anticancer medication. Four indications were investigated in more detail. ResultsA wide distribution in patient volumes within hospitals was observed. Top clinical hospitals generally treated the most patients per hospital, followed by general and academic/specialised oncology hospitals. The volume cut off points showed that in 19 indications (50%) the majority (>50%) of all hospitals treated less than 10 patients and in 25 indications (66%) the majority of all hospitals treated less than 30 patients with anticancer medication. Four case studies demonstrated that relatively few hospitals treat many patients while many hospitals treat few patients with anticancer medication. ConclusionIn the majority of oncology indications, a large proportion of Dutch hospitals treat small numbers of unique patients with anticancer medication. The high level of fragmentation gives ground for further exploration and discussion on how the organisation of care can support optimization of the efficiency and quality of care. Professional groups, policy makers, patients, and healthcare insurers should consider per indication whether centralisation is warranted.

Overall Survival of Adult Acute Lymphoblastic Leukemia (ALL) Patients By Facility Volume and Type: A National Cancer Database Report

Introduction: The majority of acute lymphoblastic leukemia (ALL) deaths occur in adults, with only 40% of adult ALL patients achieving 5-year leukemic-free survival, and decreasing cure rates with increasing age (Abuasab 2021). ALL treatment is variable across facilities, based on patient and disease features, along with institutional factors (Khullar, 2022). Currently, there are limited studies that investigate adult ALL overall survival (OS) outcomes by facility characteristics. The primary objective of our study was to determine adult ALL OS by facility volume and type for adult patients. Methods: This retrospective study analyzed de-identified National Cancer Database (NCDB) files from 2004-2016. ALL patients >18 years of age met inclusion criteria. Facility type was not available for patients <40 years of age, and was excluded from analysis. Baseline patient characteristics were extracted and sub-grouped by age >18 to <40 and >40. Summary statistics included frequency (%) for categorical variables and median [IQR] for non-normal continuous variables. Group differences were compared with Chi-square or Kruskal-Wallis rank sum tests. Facility volume was determined by a maximally selected log-rank statistics, with high volume (HV) versus low volume (LV) cut point at >91%. Academic programs (APs) included academic/research and integrated network cancer programs. Community programs (CPs) included community and comprehensive community programs. OS Kaplan Meier (KM) curves censored by death or last follow-upwere created for facility volume and type. Analysis was conducted with R software 4.0.3. The NCDB is a joint project of the Commission on Cancer of the American College of Surgeons and the American Cancer Society, these institutions have not verified and are not responsible for the methodology or findings of this research. Results: 22,453 ALL patients were included in the study (>18 to <40 years N=7860; >40 years N=14,593). 12,453 (55.5%) patients were treated at HV and 10,000 (44.5%) at LV centers. 9708 (66.5%) of patients >40 years were treated at APs and 4885 (33.5%) patients were treated at CPs. For both age cohorts, patients were more likely to be male, White, Non-Hispanic, have a Charlson Comorbidity Index of 0, private insurance, a median income >$63,000, and reside in a metro area 10-100 miles from the treatment center (P < 0.001)(Table 1). Analysis of patients >18 to <40 years found no significant OS difference between patients treated at LV and HV centers (mOS 64.4 mo., 95% CI 62.2-67.6 vs. 60.9 mo., 58.2-63.4; p = 0.1). Analysis of patients >40 years found longer OS in patients treated at LV CP (red line) compared to HV AP (purple line) (mOS 71.1 mo., 95% CI 66.6-75.8% vs. mOS 56.9 mo., 95% CI 56.6-62.7; P <0.0001) (Figure 1). OS was greater at LV compared to HV centers (mOS 68.7 mo., 95% CI 65.2-71.5 vs. 59.5 mo., 95% CI 56.6-62.3; P < 0.0001) and OS was greater at CPs compared to APs (mOS 69.2 mo., 95% CI 65.0-72.6 vs. 61.2 mo., 95% CI 58.5-63.4; p = 0.00049). Discussion: This large, national study provides insight into OS in adult ALL patients by treatment facility. Despite a paucity of differences in patient characteristic trends between age cohorts, we found OS differed by facility volume in older ALL patients but not younger adult patients. Interestingly, OS of young adult ALL patients was not uniformly superior to older patients. OS in patients >40 years was longest in those treated at LV and CPs, and shortest amongst patients treated at HV and APs. Potentially, patients with more advanced/high-risk disease, and therefore worse prognosis, were selectively treated at HV and APs, accounting for inferior OS. Additionally, perhaps more aggressive treatments were attempted at HV and APs, increasing risk of death in the older adult population. Finally, differences in sociodemographics may have driven OS differences. Our study was limited by its retrospective nature, the delay in reported NCDB data and current clinical practice, and missing facility type for patients <40 years. Conclusion: OS in adult ALL patients >40 years was significantly different by facility volume and type, with the greatest OS in patients treated at LV and CPs, and the least OS at HV and APs. Amongst patients >18 to 40 years of age, there was no difference in OS by facility volume. Future research is needed to understand and improve adult ALL OS trends observed between treatment facilities. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Volume and Outcomes of Joint Arthroplasty

BackgroundJoint arthroplasties are among the most commonly performed elective surgeries in the United States. Surgical outcomes are known to improve with volume but it is unclear whether this has led to consolidation among elective surgeries. We examined trends in volumes per surgeon and hospital to assess whether the known volume-outcome relationship has led to consolidation in elective joint arthroplasty and to determine if there exist volume thresholds above which outcomes do not change. MethodsAmong Medicare beneficiaries who underwent either total knee or total hip arthroplasty from 2009 through 2015, we described volume trends and used mixed-effect models to relate annual surgeon and hospital volumes with 30-day complications or mortality. We tested for optimal volume cut points at both the hospital and surgeon level. ResultsAdjusted annual complication rates were inversely associated with volume for both procedures at both the surgeon level and hospital level, but there was minimal consolidation between 2009 and 2015. Complications no longer declined after volumes of each case exceeded 260 per year. The vast majority of cases (around 93% of hip and 88% of knee arthroplasties) were performed by surgeons operating at suboptimal volumes. ConclusionMore than 2 decades after the volume-outcome relationship was established for joint arthroplasty, many cases continue to be performed by low-volume surgeons, with far more cases performed by surgeons operating at suboptimal volumes. Further improvement could be expected through consolidation at both the hospital and surgeon level, with a target of at least 260 cases per surgeon annually for each operation. Payers seem best-equipped to drive consolidation.

Hospital surgical volume-outcome relationship in caesarean hysterectomy for placenta accreta spectrum.

To examine the association between hospital surgical volume of caesarean hysterectomy and surgical morbidity in women with placenta accreta spectrum (PAS). Population-based retrospective cohort study. National Inpatient Sample, January 2016 to December 2018. Six thousand and ten women with PAS who underwent caesarean hysterectomy in 738 centres. (1) Comprehensive modelling for relative hospital surgical volume cut-point selection, (2) multinomial regression analysis for characterising hospital surgical volume, and (3) binary logistic regression analysis to examine the volume-outcome relationship. Surgical morbidity (haemorrhage, coagulopathy, shock, urinary tract injury, and death). The majority of centres had five surgeries over the 3-year period (468 centres, 63.4%) and were grouped as the low-volume group. Surgical morbidity decreased after a relative hospital surgical volume of 25 cases (24 centres, 3.3%) was reached, grouped as the high-volume group. The remaining centres were grouped as the mid-volume group (246 centres, 33.3%). In multivariable analysis, women in the high-volume group were more likely to be Black, have lower median household income, medical comorbidity, previous caesarean delivery, placenta praevia or placenta percreta, and to have undergone surgeries at large urban teaching hospitals compared with those in the low-volume group (all, P < 0.05). After controlling for patient demographics, hospital characteristics and pregnancy factors, performance of caesarean hysterectomy at high-volume centres was associated with a 22% decreased risk of surgical complications compared with surgery at the low-volume centres (adjusted odds ratio 0.78, 95% CI 0.64-0.94). Caesarean hysterectomy for PAS is a rare surgical procedure. Higher hospital surgical volume may be associated with improved surgical outcome in PAS. Higher hospital caesarean hysterectomy volume may be associated with improved surgical outcome in PAS.

Use of the ABC/2 Method to Select Patients for Thrombectomy After 6 Hours of Symptom Onset.

To determine whether the ABC/2 method could accurately and reliably measure infarct volume and guide thrombectomy decision in acute stroke cases presenting with late or unknown onset. Four physicians who routinely use MRI for acute stroke imaging, blinded to the RAPID results, measured the diffusion-weighted imaging (DWI) infarct volume using the ABC/2 method. Measurements with ABC/2 (the index test) were compared with RAPID (the reference standard) to calculate sensitivity, specificity, and accuracy measures for various volume cutpoints. Thrombectomy decisions based on RAPID and raters' measurements using the criteria from the Diffusion-Weighted Imaging or Computerized Tomography Perfusion Assessment With Clinical Mismatch in the Triage of Wake-Up and Late-Presenting Strokes Undergoing Neurointervention With Trevo (DAWN) trial criteria were compared. Interrater and intrarater agreement was measured using kappa statistics. Accuracy with the ABC/2 method was greater than 80% for each rater and each volume cut point. Interrater and intrarater agreement was substantial to excellent for each volume cut point. Treatment decisions with ABC/2 volume estimations showed strong interrater and intrarater agreement, and led to similar thrombectomy decisions compared with RAPID in more than 85% of cases. DWI infarct volume measurement using ABC/2 method shows strong accuracy and reliability and may be an acceptable alternative to RAPID software for the application of DAWN criteria for thrombectomy decision-making.

Relation Between Operator and Hospital Volumes and Long-Term Outcomes for Percutaneous Coronary Intervention in New York

Little is known about whether there is an inverse relation between provider volume and long-term adverse outcomes for percutaneous coronary interventions (PCIs). For patients who underwent PCI procedures from December 2013 through November 2014 in New York, we examined a continuous relation and different annual PCI volume cut points at hospital and operator levels to investigate the relation between volume and 1-year adverse outcomes (mortality and mortality/acute myocardial infarction). There were 34,498 patients who underwent PCI procedures from 60 hospitals and 408 operators. We detected a significant continuous inverse association between 1-year mortality and annual hospital PCI volume. However, we did not find that there was a hospital volume and 1-year mortality relation for the 2013 ACCF/AHA/SCAI's hospital annual PCI volume cutoff value of 200 or a significant inverse operator volume-outcome relation using the operator annual PCI volume cutoff value of 50, or for any other practical volume cutoffs. Similar findings were obtained when we used the 1-year mortality/acute myocardial infarction outcome. We did find that providers in the highest volume quartile were associated with lower adverse outcome rates than providers in the lowest volume quartile. In conclusion, no significant volume-outcome relations were found between annual hospital or operator PCI volume and risk-adjusted 1-year outcomes for any practical volume cutoff values including 2013 Guidelines' recommended hospital/operator minimal annual PCI volumes. Providers in the highest annual volume quartile, however, were associated with lower adverse outcome rates than providers in the lowest volume quartile.

Patterns of care for women with placenta accreta spectrum

Background Placenta accreta spectrum (PAS) is a spectrum of conditions in which the placenta is abnormally adherent and invades the uterine wall. This invasion can cause life-threatening hemorrhage and lead to significant adverse maternal outcomes. Numerous studies have shown an association between treatment of PAS at high volume, specialized centers and improved maternal outcomes; however, little is known about how these data have influenced practice. Objective The objective of the study was to examine the patterns of care for women with placenta accreta spectrum over time. Study design Data from New York Statewide Planning and Research Cooperative System (SPARCS) from 2000 to 2017 was used for this analysis. The study cohort comprised of women aged 15–54 years with PAS who underwent a hysterectomy during their delivery hospitalization. Study outcomes included severe maternal morbidity as defined by the Centers for Disease Control and Prevention, surgical complications, and transfusion. Hospitals were stratified into tertiles based on the volume of PAS hysterectomy cases. Patient demographic and clinical characteristics were compared across volume tertiles. Random intercept log-linear regression models with Poisson distributions and log link functions were fit to examine the association between hospital PAS volume and the outcomes of interest. Results A total of 1958 women with PAS who underwent hysterectomy at 123 hospitals were identified. The number of hospitals providing care ranged from 46 centers in 2000 to 52 hospitals in 2016. The median hospital-level case volume of PAS was 1 (interquartile range [IQR], 1–2) in 2000 and rose slightly to 2 (IQR, 1–4) by 2016. The PAS volume cut-point for the top decile of hospitals was three cases in 2000 and increased to six cases in 2016. There was no significant change in the median travel distance for women with PAS over time. The rate of severe maternal morbidity increased significantly from 14.1% (95% CI: 7.8–24.0%) in 2000 to 19.0% (95% CI: 13.6–25.8%) in 2016. Transfusion occurred in 66.2% (95% CI: 54.6–76.1%) of cases in 2000 compared to 60.1% (95% CI: 52.3–67.4%) in 2016. Surgical complications occurred in 16.9% (95% CI: 9.9–27.3%) of cases in 2000 to 24.7% (95% CI: 18.6–32.0) in 2016. There was no difference in the adjusted rates of transfusion or surgical complications based on hospital volume. Compared to low-volume centers, the risk of severe maternal morbidity was reduced by 33% (aRR = 0.67; 95% CI: 0.50–0.90) at the intermediate volume centers. Conclusion There has been little change in the patterns of care for women with PAS in New York State. While the volume of patients with PAS has increased at the highest volume centers, a large number of relatively low-volume centers still provide care for a significant number of women with PAS.

P4522Intravascular volume expansion mitigates the impact of impaired renal function and associated clinical outcomes in chronic heart failure

Abstract Background/Introduction Intravascular volume is regulated by the kidneys but the interconnection of the extent of volume expansion with renal function and outcomes in patients with chronic HF has not been assessed. Therefore, we evaluated how GFR-defined renal function and HF-related clinical outcomes are impacted by the relative extent of intravascular volume expansion. Our hypothesis was that greater rather than lesser volume expansion would be protective of worse renal function and contribute to better clinical outcomes than mild-moderate volume expansion. Purpose Assess the impact of quantitated intravascular volume expansion on heart failure (HF) outcomes in relation to renal function in post-hospital clinically determined “euvolemic” chronic HF patients. Methods Blood volume (BV) was prospectively measured in 87 HF patients considered clinically “euvolemic” post-diuresis at the time of hospital discharge using a standardized radiolabeled albumin indicator-dilution technique (Daxor Corp., NY, NY). A volume cut-point of ≥+25% above normal expected BV was used to define the greater degree of volume expansion from more mild-moderate expansion. These volume subgroups were then stratified by cohort median eGFR (46 mL/min/1.73m2) and analyzed for 1-year outcomes of HF-related mortality or 1st re-hospitalization using the Kaplan-Meier method. Results Volume expansion ≥+25% was demonstrated in 53% of the cohort at the time of hospital discharge despite hospital diuretic therapy. In this subgroup over 1.0 year of follow-up the risk for the composite outcome was significantly lower than in the group with mild-moderate volume expansion (Log-Rank p=0.017). Further, in the clinical setting of greater volume expansion, worse renal function with eGFR below the cohort median (&lt;46 mL/min/1.73m2) was not associated with increased risk for the composite end-point (Figure). In contrast, low eGFR in the presence of mild-moderate volume expansion stratified risk and was associated with worse outcome relative to a higher eGFR above the median (Figure). Figure 1 Conclusions In post-hospital chronic HF patients significant intravascular volume expansion is common, and importantly the extent of BV expansion impacts outcomes including HF-related mortality. However, greater rather than lesser volume expansion appears to favorably mitigate the impact of worse renal function (low eGFR), while normal or mild-moderate expansion does not spare the impact of worse renal function on outcomes. Thus, a favorable degree of volume expansion appears to balance the risks of worse renal function. Volume-kidney interconnections are complex with volume status modulating the impact of impaired renal function on outcomes in chronic HF. Acknowledgement/Funding None

Persistent Intravascular Volume Expansion is Compensatory, Not Detrimental, in Post-Hospital Chronic Heart Failure Patients and Associated with Better Clinical Outcomes

Background Intravascular volume is largely regulated by the kidneys but how the relative extent of volume expansion impacts outcomes in post-hospital chronic heart failure (HF) patients has not been assessed. Our hypothesis was that greater rather than lesser volume expansion is compensatory and associated with better HF-related outcomes. Methods Blood volume (BV) was prospectively measured in 87 HF patients at the time of hospital discharge (post-diuretic therapy) using a standardized nuclear medicine radiolabeled albumin indicator-dilution technique (Daxor Corp., NY, NY). A volume cut-point of ≥+25% above normal BV defined greater from lesser volume expansion. The cohort was analyzed for 1-year composite outcome of HF-related mortality or 1st re-hospitalization. Results BV expansion ≥+25% was present in 53% of the cohort with RBC mass excess (polycythemia) being the predominant contributor (74% of this subgroup). In this volume expanded subgroup (N=46) the risk for the composite endpoint was significantly lower than in the subgroup with less volume expansion (N=41; 56% with normal BV, 44% with mild-moderate BV expansion) [Fig. 1, p=0.017, RR 0.41 (0.20-0.84)]. Further, the evaluation of RBC mass as a component of intravascular volume informs the higher risk associated with true anemia [p=0.006, RR 2.78 (1.37-5.55)], but also importantly the significant reduction in risk associated with RBC polycythemia [p Conclusions The findings of this analysis indicate that persistent intravascular volume expansion (≥+25% above normal volume) is common at the time of hospital discharge despite diuretic intervention in chronic HF patients, and importantly that in post-hospital follow up the greater extent of BV expansion (compared to normal volume or mild-moderate expansion) driven mainly by RBC polycythemia is compensatory, not detrimental, and associated with better HF-related outcomes including reduced mortality. These findings provide additional insight into the pathophysiology of chronic HF and also have implications for a more individualized approach to volume assessment and management in HF patients.

Relationship between operator and hospital volumes and short-term mortality for percutaneous coronary intervention in New York

BackgroundRecent studies have reported mixed findings regarding the inverse provider volume-outcome relationship for percutaneous coronary interventions (PCIs). MethodsWe included patients who underwent PCIs in New York during December 2012–November 2015. Using risk-adjusted in-hospital/30-day mortality rate and appropriateness of PCI, we tested for a continuous relationship and a variety of annual PCI volume cut points at hospital and operator levels in investigating volume-outcome relationships. ResultsThere were 144,196 patients undergoing PCI procedures from 63 non-federal hospitals. There was a significant inverse association between risk-adjusted mortality and both annual hospital PCI volume and annual operator PCI volume. However, we did not find that there was an inverse hospital volume-outcome relationship for the 2013 ACCF/AHA/SCAI's hospital PCI volume cutoff value of 200 per year (AOR, 1.15, 95% CI, 0.88–1.51, P = 0.32) or a significant inverse operator volume-outcome relationship using the operator PCI volume cutoff value of 50 per year (AOR, 0.89, 95% CI, 0.70–1.12, P = 0.32) or for any other practical volume cutoffs. There was also no significant volume-outcome relationship for STEMI patients. Higher volume hospitals (>400) and operators (>200) tended to perform a higher percentage of inappropriate PCI procedures than their lower volume counterparts. ConclusionThere were no significant PCI volume-mortality relationships for either hospitals or operators for any practical volume cuts. Higher volume hospitals and operators were associated with higher percentages of inappropriate PCIs.

Tolerance doses for late adverse events after hypofractionated radiotherapy for prostate cancer on trial NRG Oncology/RTOG 0415

Purpose/objectiveHypofractionated radiotherapy (HRT) regimens for prostate cancer are emerging, but tolerance doses for late adverse events are scarce. The purpose of this study is to define dose–volume predictors for late gastrointestinal and genitourinary (GI and GU) toxicities after HRT in the multi-center NRG Oncology/RTOG 0415 low-risk prostate cancer trial (N = 521). Material/methodsTreatment in the studied HRT arm was delivered as 70 Gy at 2.5 Gy/fraction with 3D-CRT/IMRT (N = 108/413). At a median follow-up of 5.9 years, the crude late ≥Grade 2 GI and GU toxicities were 19% and 29%, respectively. For modeling, the complete HRT cohort was randomly split into training and validation (70% and 30%; preserved toxicity rates). Within training, dose–response modeling was based on dose–volume cut-points (EQD2Gy; bladder/rectum: α/β = 6 Gy/3Gy), age, acute ≥Grade 2 toxicity, and treatment technique using univariate and multivariate logistic regression on bootstrapping (UVA and MVA). Candidate predictors were determined at p ≤ 0.05, and the selected MVA models were explored on validation where model generalizability was judged if the area under the receiver-operating curve in validation (AUCvalidation) was within AUCtraining ± SD with p ≤ 0.05, and with an Hosmer–Lemeshow p-value (pHL) > 0.05. ResultsThree candidate predictors were suggested for late GI toxicity: the minimum dose to the hottest 5% rectal volume (D5%[Gy]), the absolute rectal volume <35 Gy, and acute GI toxicity (AUC = 0.59–0.63; p = 0.02–0.04). The two generalizable MVA models, i.e., D5%[Gy] with or without acute GI toxicity (AUCvalidation = 0.64, 0.65; p = 0.01, 0.03; pHL = 0.45–0.56), suggest that reducing late GI toxicity from 20% to 10% would require reducing D5%[Gy] from ≤65 Gy to ≤62 Gy (logistic function argument: 17+(0.24D5%[Gy])). Acute GU toxicity showed only a trend to predict late GU toxicity (AUCtraining = 0.57; p = 0.07). ConclusionLate GI toxicity, following moderate HRT for low-risk prostate cancer, increases with higher doses to small rectal volumes. This work provides quantitative evidence that limiting small rectal dose ‘hotspots’ in clinical practice of such HRT regimens is likely to further reduce the associated rates of GI toxicity.

Visual assessment of diffusion weighted imaging infarct volume lacks accuracy and reliability

PurposeThe DAWN trial (Diffusion weighted imaging or CT perfusion Assessment with clinical mismatch in the triage of Wake-up and late presenting strokes undergoing Neurointervention with Trevo) has demonstrated the benefits...

Abstract TP68: Visual Assessment of Diffusion-Weighted-Imaging Infarct Volume Lacks Accuracy and Reliability

Introduction: Patients screened by MRI in the extended window (6-24hr) for mechanical thrombectomy (MT) might require the treating physician to visually estimate the DWI infarct volume at institutions where the RAPID software is not available. We aimed to assess the accuracy of DWI volume estimation compared with RAPID, as well as the interrater and intrarater agreement among physicians. Methods: Eighteen raters (all physicians involved on daily stroke management) assessed over two independent sessions 32 MR scans from a prospective MT database. Raters generated a visual estimate of the DWI infarct volume and were asked whether they would recommend MT for the assessed patient or not. Sensitivity, specificity and accuracy of the estimated volumes were compared with the available RAPID measurements for various volume cut-points. Interrater and intrarater agreement was measured using Fleiss’ kappa statistics. Results: Raters mean accuracy was &lt;90% for all volume cut-points ( A ). Interrater agreement was below substantial for each DWI infarct volume cut-point ( B ). Intrarater agreement was substantial for 55-83% of raters, depending on the selected cut-point ( C ). Raters recommended MT for a mean of 77% of patients, including a mean of 56% of patients with an estimated infarct volume≥71ml. Conclusion: The visual assessment of DWI infarct volume lacks accuracy when RAPID measurements are the reference values. Less-than-substantial reproducibility of the volume estimates was demonstrated among physician raters who recommended MT for large infarct volumes despite the absence of rigorous scientific evidence.

Optimal Hematoma Volume Cut Points to Predict Functional Outcome After Basal Ganglia and Thalamic Hemorrhages.

Basal ganglia hemorrhage (BG-ICH) and thalamic hemorrhage (TH-ICH) have been historically grouped into a single "deep" hemorrhage group in prior studies. We aimed to assess whether BG-ICH and TH-ICH have different optimal hematoma volume cut points in predicting functional outcome. Patients with BG-ICH and TH-ICH with no preexisting disabilities who were enrolled in a single-center intracerebral hemorrhage (ICH) cohort study were studied. The hematoma volume of patients who achieved modified Rankin Scale (mRS) of ≤2 and ≤3 at 3 months were compared between BG-ICH and TH-ICH groups. Receiver operating characteristic (ROC) curves were created to determine the optimal hematoma volume cut points in predicting 3-month mRS of ≤2 and ≤3 for BG-ICH and TH-ICH groups. A total of 135 (81 BG-ICH and 54 TH-ICH) patients were studied. The hematoma volume among those with 3-month mRS ≤ 2 (BG-ICH: 9.5 ± 5.4 cm3 vs. TH-ICH: 5.1 ± 4.9 cm3, p = 0.01) and 3-month mRS ≤ 3 (BG-ICH: 14.2 ± 13.4 cm3 vs. TH-ICH: 4.7 ± 4.1 cm3, p = 0.001) were smaller in TH-ICH than BG-ICH. The area under the ROC curve in predicting mRS ≤ 2 was 0.838 for BG-ICH (optimal hematoma volume cut point: 18.0 cm3, sensitivity 72.1%, specificity 95.0%) and 0.802 for TH-ICH (optimal hematoma volume cut point: 4.6 cm3, sensitivity 83.8%, specificity 70.6%); and in predicting mRS ≤ 3 was 0.826 for BG-ICH (optimal hematoma volume cut point: 28.8 cm3, sensitivity 71.4%, specificity 93.8%) and 0.902 for TH-ICH (optimal hematoma volume cut point: 5.5 cm3, sensitivity 92.9%, specificity 76.9%). TH-ICH have smaller optimal hematoma volume cut points than BG-ICH in predicting functional outcome.

Establishing benchmarks for the volume-outcome relationship for common lumbar spine surgical procedures

Background ContextThe importance of surgeon volume as a quality measure has been defined for a number of surgical specialties. Meaningful procedural volume benchmarks have not been established, however, particularly with respect to lumbar spine surgery. PurposeWe aimed to establish surgeon volume benchmarks for the performance of four common lumbar spine surgical procedures (discectomy, decompression, lumbar interbody fusion, and lumbar posterolateral fusion). Study DesignA retrospective review of data in the Florida Statewide Inpatient Dataset (2011–2014) was carried out. Patient SamplePatients who underwent one of the four lumbar spine surgical procedures under study comprised the study sample. Outcome MeasureThe development of a complication or hospital readmission within 90 days of the surgical procedure was the surgical outcome. MethodsFor each specific procedure, individual surgeon volume was separately plotted against the number of complications and readmissions in a spline analysis that adjusted for co-variates. Spline cut-points were used to create a categorical variable of procedure volume for each individual procedure. Log-binomial regression analysis was then separately performed using the categorical volume-outcome metric for each individual procedure and for the outcomes of 90-day complications and 90-day readmissions. ResultsIn all, 187,185 spine surgical procedures met inclusion criteria, performed by 5,514 different surgeons at 178 hospitals. Spline analysis determined that the procedure volume cut-point was 25 for decompressions, 40 for discectomy, 43 for interbody fusion, and 35 for posterolateral fusions. For surgeons who failed to meet the volume metric, there was a 63% increase in the risk of complications following decompressions, a 56% increase in the risk of complications following discectomy, a 15% increase in the risk of complications following lumbar interbody fusions, and a 47% increase in the risk of complications following posterolateral fusions. Findings were similar for readmission measures. ConclusionsThe results of this work allow us to identify meaningful volume-based benchmarks for the performance of common lumbar spine surgical procedures including decompression, discectomy, and fusion-based procedures. Based on our determinations, readily achievable goals for individual surgeons would approximate an average of four discectomy and lumbar interbody fusion procedures per month, three posterolateral lumbar fusions per month, and at least one decompression surgery every other week.

Abstract T P46: Final Infarct Volume Discriminates Outcome In Mild Strokes

Introduction: Final infarct volume (FIV) is a well-established predictor of outcomes in moderate and severe stroke. However, our knowledge of how FIV predicts disability in the mild stroke population is very limited. Our objective was to determine if FIV could differentiate good versus poor outcome after mild stroke. We hypothesized that smaller FIV will be associated with favorable clinical outcome. Methods: We used a retrospective, multicenter registry for consecutive patients who presented with mild stroke (NIHSS ≤ 5) within 24 hours of stroke onset. The imaging data included baseline head CT, noninvasive vascular imaging and follow up imaging (24-72 hour MR/3-5 day CT). Baseline ASPECTS, proximal arterial occlusion (PAO), collateral scores and FIV (using MIPAV) were assessed by core lab. Clinical data included age, sex, baseline NIHSS and 90 day modified Rankin Scale (mRS). Logistic regression was used to evaluate associations between favorable outcome (mRS 0-1) and imaging and clinical data, and to determine a data-driven cut-point for FIV based on the maximal sensitivity and specificity of the receiver operating characteristic curve. Results: Among 90 patients with mild stroke, 3 who received intravenous thrombolysis and 22 who did not have follow-up imaging were excluded, leaving 65 patients (mean age 86 years, 38% female, median NIHSS score 4) in whom FIV calculations were performed. An optimal FIV cut-point at 20 cc was identified, for differentiating between favorable and poor outcomes (area under curve 0.73, 95% CI: 0.58-0.88). Of the 45 patients with FIV &lt;20 cc, 37 (82%) had a favorable outcome compared to 5 out of 14 (36%) with FIV ≥ 20 cc (P&lt;.01). In the multivariable model, FIV ≥ 20cc remained strongly associated with poor outcome (adjusted OR, 0.11; 95% CI, 0.02- 0.50, P&lt;.01), irrespective of age, gender, stroke severity, ASPECTS and PAO. A higher collateral score was also found to be associated with favorable outcome (adjusted OR, 2.43; 95% CI, 1.12- 5.27, P=0.02). Conclusions: A final infarct volume cut point of 20 cc was found to best differentiate between the likelihood of good versus poor outcome in patients with mild stroke. Further validation of FIV as a surrogate marker is essential to improve risk prediction in mild stroke patients.

Infarct volume predicts critical care needs in stroke patients treated with intravenous thrombolysis.

Patients receiving intravenous thrombolysis with recombinant tissue plasminogen activator (IVT) for ischemic stroke are monitored in an intensive care unit (ICU) or a comparable unit capable of ICU interventions due to the high frequency of standardized neurological exams and vital sign checks. The present study evaluates quantitative infarct volume on early post-IVT MRI as a predictor of critical care needs and aims to identify patients who may not require resource intense monitoring. We identified 46 patients who underwent MRI within 6 h of IVT. Infarct volume was measured using semiautomated software. Logistic regression and receiver operating characteristics (ROC) analysis were used to determine factors associated with ICU needs. Infarct volume was an independent predictor of ICU need after adjusting for age, sex, race, systolic blood pressure, NIH Stroke Scale (NIHSS), and coronary artery disease (odds ratio 1.031 per cm(3) increase in volume, 95% confidence interval [CI] 1.004-1.058, p = 0.024). The ROC curve with infarct volume alone achieved an area under the curve (AUC) of 0.766 (95% CI 0.605-0.927), while the AUC was 0.906 (95% CI 0.814-0.998) after adjusting for race, systolic blood pressure, and NIHSS. Maximum Youden index calculations identified an optimal infarct volume cut point of 6.8 cm(3) (sensitivity 75.0%, specificity 76.7%). Infarct volume greater than 3 cm(3) predicted need for critical care interventions with 81.3% sensitivity and 66.7% specificity. Infarct volume may predict needs for ICU monitoring and interventions in stroke patients treated with IVT.