Intermediate-volume Centers Research Articles

How Small Is Too Small? A Systematic Review of Center Volume and Outcome After Cardiac Transplantation

The aim of this study was to assess the relationship between the volume of cardiac transplantation procedures performed in a center and the outcome after cardiac transplantation. PubMed, Embase, and the Cochrane library were searched for articles on the volume-outcome relationship in cardiac transplantation. Ten studies were identified, and all adopted a different approach to data analysis and varied in adjustment for baseline characteristics. The number of patients in each study ranged from 798 to 14401, and observed 1-year mortality ranged from 12.6% to 34%. There was no association between the continuous variables of center volume and observed mortality. There was a weak association between the continuous variables of center volume and adjusted mortality up to 1 year and a stronger association at 5 years. When centers were grouped in volume categories, low-volume centers had the highest adjusted mortality, intermediate-volume centers had lower adjusted mortality, and high-volume centers had the lowest adjusted mortality but were not significantly better than intermediate-volume centers. Category limits were arbitrary and varied between studies. There is a relationship between center volume and mortality in heart transplantation. The existence of a minimum acceptable center volume or threshold is unproven. However, a level of 10 to 12 heart transplants per year corresponds to the upper limit of low-volume categories that may have relatively higher mortality. It is not known whether outcomes for patients treated in low-volume transplant centers would be improved by reorganizing centers to ensure volumes in excess of 10 to 12 heart transplants per year.

Total cost and operating room time comparison of rotator cuff repair techniques at low, intermediate, and high volume centers: Mini-open versus all-arthroscopic

The objective of this study was to determine mean cost and operative time differences between mini-open and all-arthroscopic rotator cuff repair techniques at surgical centers of low, intermediate, and high annual rotator cuff repair volume. The 2006 New York State Ambulatory Surgery Database (NY-SASD) was utilized. It represents 100% of all outpatient procedures performed in hospital-affiliated and freestanding surgical centers, containing 10,658,923 patients for 2006 alone. Only patients who had an arthroscopic acromioplasty and either open or arthroscopic rotator cuff repair were included, leaving 5,224 patients for the study. These were divided into 2 groups: the mini-open group (1,334) and the all-arthroscopic group (3,890). Surgical center volume data were divided into 3 groups: low volume (<75 rotator cuff repairs per year), intermediate volume (75-199 rotator cuff repairs per year), and high volume (200+ rotator cuff repairs per year). Patient age and gender were normally distributed within the 2 groups with no significant differences between them (P = .82 and P = .31, respectively). Operative time was significantly shorter in the mini-open group (103 minutes) compared to the all-arthroscopic group (113 minutes), P < .00001. Surgical charges were also significantly less in the mini-open group ($7,841) compared to the all-arthroscopic group ($8,985), P < .00001. Regardless of the repair method, high volume surgical centers were significantly more expensive when compared to low and intermediate volume centers, P < .00001. The mini-open rotator cuff repair technique requires significantly less operative time and is significantly less expensive than the all-arthroscopic repair. Regardless of the repair technique, high volume surgical centers cost significantly more than low and intermediate volume surgical centers.

Transplantation of Kidneys from Donors at Increased Risk for Blood-Borne Viral Infection: Recipient Outcomes and Patterns of Organ Use

Kidney transplantation from deceased donors classified as increased risk for viral infection by the Centers for Disease Control (CDC) is controversial. Analyses of Organ Procurement and Transplantation Network (OPTN) data from 7/1/2004 to 7/1/2006 were performed. The primary cohort included 48 054 adults added to the kidney transplant wait list. Compared to receiving a standard criteria donor (SCD) kidney or remaining wait-listed, CDC recipients (HR 0.80, p = 0.18) had no significant difference in mortality. In a secondary cohort of 19 872 kidney recipients at 180 centers, SCD (reference) and CDC (HR 0.91, p = 0.16) recipients had no difference in the combined endpoint of allograft failure or death. Among centers performing >10 kidney transplants during the study period, the median proportion of CDC transplants/total transplants was 7.2% (range 1.1-35.6%). Higher volume transplant centers were more likely to use CDC kidneys compared to low and intermediate volume centers (p < 0.01). An analysis of procured kidneys revealed that 6.8% of SCD versus 7.8% of CDC (p = 0.13) kidneys were discarded. In summary, center use of CDC kidneys varied widely, and recipients had good short-term outcomes. OPTN should collect detailed data about long-term outcomes and recipient viral testing so the potential risks of CDC kidneys can be fully evaluated.

Sirolimus-Eluting Stent Treatment at High-Volume Centers Confers Lower Mortality at 6-Month Follow-Up

Studies continue to identify percutaneous coronary intervention procedural volume both at the institutional level and at the operator level as being strongly correlated with outcome. High-volume centers have been defined as those that perform >400 percutaneous coronary intervention procedures per year. The relationship between drug-eluting stent procedural volume and outcome is unknown. We investigated this relationship in the German Cypher Registry. The present analysis included 8201 patients treated with sirolimus-eluting stents between April 2002 and September 2005 in 51 centers. Centers that recruited >400 sirolimus-eluting stent patients in this time period were considered high-volume centers; those with 150 to 400 patients were considered intermediate-volume centers; and those with <150 patients were designated as low-volume centers. The primary end point was all death, myocardial infarction, and target-vessel revascularization at 6 months. This end point occurred in 11.3%, 12.1%, and 9.0% of patients in the low-, intermediate-, and high-volume center groups, respectively (P=0.0001). There was no difference between groups in the rate of target-vessel revascularization (P=0.2) or cerebrovascular accidents (P=0.5). The difference in death/myocardial infarction remained significant after adjustment for baseline factors (odds ratio 1.85, 95% confidence interval 1.31 to 2.59, P<0.001 for low-volume centers; odds ratio 1.69, 95% confidence interval 1.29 to 2.21, P<0.001 for intermediate-volume centers). Patient and lesion selection, procedural features, and postprocedural medications differed significantly between groups. The volume of sirolimus-eluting stent procedures performed on an institutional level was inversely related to death and myocardial infarction but not to target-vessel revascularization at 6-month follow-up. Safety issues are better considered in high-volume centers. These findings have important public health policy implications.

Transplant Center Volume and Outcomes After Liver Retransplantation

Liver retransplantation surgery has a high rate of allograft failure due to patient comorbidities and technical demands of the procedure. Success of liver retransplantation could depend on surgeon experience and processes of care that relate to center volume. We performed a retrospective cohort study of adult liver retransplantation procedures performed from January 1, 1996 through December 31, 2005 using registry data from the Organ Procurement Transplantation Network. The primary outcome was 1-year allograft failure. Liver transplant centers were categorized as small, intermediate or high volume by dividing overall liver transplants into three tertiles of approximately equal size. Mean annual volume of overall liver transplants was <50 for low-volume centers, 50-88 for intermediate-volume centers and >88 for high-volume centers. The primary analysis consisted of 3977 liver retransplantation patients. The unadjusted risk of 1-year allograft failure was 37.8%. In multivariable logistic regression, the risk of 1-year allograft failure was not significantly different between low- (reference), intermediate- (OR 0.86, CI 0.72-1.03, p = 0.11) and high-volume centers (OR 0.88, CI 0.74-1.04, p = 0.14). Results were similar when the analysis was limited to retransplantation performed >160 days after initial transplantation. Center volume is an imprecise surrogate measure for 1-year outcomes after liver retransplantation.

Impact of Hospital Volume on Surgical Outcome for Head and Neck Cancer

The objective of this study was to define the prognostic significance of surgical center case volume on outcome for head and neck cancer (HNC). Florida cancer registry and inpatient hospital data were queried for HNC diagnosed from 1998 to 2002. Of the 11,160 operative cases of HNC identified, 35.3% were treated at low-volume centers (LVCs), 32.7% in intermediate-volume centers (IVC), and 32.1% at high-volume centers (HVC). A larger proportion of high-grade tumors (27.9%) and lesions over 30 mm (39.7%) were resected at HVC (p < 0.001). Median survival was 61 months for HVC, 52 months for IVC, and 47 months for LVC (p < 0.001). Univariate analysis demonstrated significantly improved survival at HVC for low-, medium-, and high-grade tumors, small tumors (<30 mm), and for cancers of the parotid, larynx, and pharynx. On multivariate analysis, corrected for patient comorbidities, treatment at a HVC was a significant independent predictor of improved survival (HR = 1.25, p = 0.001). We conclude that HNC patients treated at HVC have significantly better long-term survival and cure rates. Where possible, patients with large (>30 mm), high-grade or parotid, larynx, and pharynx tumors should be evaluated and offered care at a high-volume center.