Annual Operator Volume Research Articles

Annual operator volume and procedural outcomes of chronic total occlusions treated with percutaneous coronary interventions: analysis based on 14,899 patients.

Low operator and institutional volume is associated with poorer procedural and long-term clinical outcomes in patients treated with percutaneous coronary interventions (PCI). This study was aimed at evaluating the relationship between operator volume and procedural outcomes of patients treated with PCI for chronic total occlusion (CTO). Data were obtained from the national registry of percutaneous coronary interventions (ORPKI) collected from January 2014 to December 2020. The primary endpoint was a procedural success, defined as restoration of thrombolysis in myocardial infarction (TIMI) II/III flow without in-hospital cardiac death and myocardial infarction, whereas secondary endpoints included periprocedural complications. Data of 14,899 CTO-PCIs were analyzed. The global procedural success was 66.1%. There was a direct relationship between the annual volume of CTO-PCIs per operator and the procedural success (OR: 1.006 [95% CI: 1.003-1.009]; P<0.001). The nonlinear relationships of annualized CTO-PCI volume per operator and adjusted outcome rates revealed that operators performing 40 CTO cases per year had the best procedural outcomes in terms of technical success (TIMI flow II/III after PCI), coronary artery perforation rate and any periprocedural complications rate (P<0.0001). Among the other factors associated with procedural success, the following can be noted: multi-vessel, left main coronary artery disease (as compared to single-vessel disease), the usage of rotablation as well as PCI within bifurcation. High-volume CTO operators achieve greater procedural success with a lower frequency of periprocedural complications. Higher annual caseload might increase the overall quality of CTO-PCI.

Procedural outcomes and annual operator volume among patients treated with percutaneous coronary intervention of chronic total occlusions – analysis based on a large national registry

Abstract Background It has been demonstrated that low operator and institutional volume is associated with poorer procedural and long-term clinical outcomes in general population of patients treated with percutaneous coronary interventions (PCI). Purpose The aim of the current study was to assess the relationship between operator volume and procedural outcomes of patients treated with PCI within chronic total occlusion (CTO). Methods Data for conducting the current analysis were obtained from the national registry of percutaneous coronary interventions (ORPKI) maintained in cooperation with the Association of Cardiovascular Interventions (AISN) of the Polish Cardiac Society. The study covered data obtained from the registry from January 2014 to December 2020. To investigate the association between operator and all periprocedural complications, coronary artery perforation (CAP) and TIMI flow grade 2/3 after PCI in the presence of confounding and clustering effects, we used multivariable, mixed effects logistic regression modelling. Results During the investigated period, there were 162 active CathLabs, at which 747,033 PCI procedures were performed during the time of observation. Of those 14,924 were CTO-PCI procedures. Considering the number of CTO-PCIs performed annually by individual operators during the analyzed 7 years we assessed differences between four groups (≤10; &amp;gt;10≤20; &amp;gt;20≤30 and &amp;gt;30 procedures). We demonstrated by nonlinear relationship with annualised CTO-PCI operator volume that operators performing more than 40 PCI with CTO per year have lower number of the overall periprocedural complications (Fig. 1) including CAP, as well greater procedural success rates (Fig. 2) compared to operators performing less procedures (p&amp;lt;0.0001). Conclusions High-volume CTO operators achieve a greater procedural success with a lower frequency of periprocedural complications. This study suggests that the cut-off of 50 CTO-PCIs per year recommended in the EuroCTO Consensus remains a reasonable compromise to optimize outcome and maintain local availability. Special CTO training programs and a higher annual case load might increase the overall quality of CTO PCI. Funding Acknowledgement Type of funding sources: None.

TCT-111 Annual Operator Volume and Procedural Outcomes Among Patients Treated With Percutaneous Coronary Intervention of Chronic Total Occlusions—Analysis Based on a Large National Registry

TCT-111 Annual Operator Volume and Procedural Outcomes Among Patients Treated With Percutaneous Coronary Intervention of Chronic Total Occlusions—Analysis Based on a Large National Registry

Association of Annual Operator Volume With the Outcomes of Chronic Total Occlusion Percutaneous Coronary Intervention.

There are limited data on the association of operator volume with the outcomes of chronic total occlusion (CTO) percutaneous coronary intervention (PCI). We analyzed the association between operator volume and procedural outcomes of 7035 CTO-PCIs performed between 2012 and February 2021 at 30 centers. The study population was divided into 3 groups based on annual operator CTO-PCI volume: low-volume operators (LVO: &lt;30 cases/year; 39.7% of the cases); medium-volume operators (MVO: 30-60 cases/year; 25.7% of the cases); and high-volume operators (HVO: &gt;60 cases/ year; 34.6% of the cases). Mean patient age was 64.4 ± 10 years and 82% were men. Cases performed by HVOs were more complex, with higher J-CTO score compared with cases performed by MVOs and LVOs (2.72 ± 1.27 vs 2.39 ± 1.19 vs 2.12 ± 1.27, respectively; P&lt;.001). Moderate/severe proximal vessel tortuosity (35% vs 23% vs 20%; P&lt;.001) and proximal cap ambiguity (44% vs 34% vs 32%; P&lt;.001) was also more common in the HVO group. Cases performed by HVOs had higher technical success rates (87.9% vs 86.9% vs 82.6%; P&lt;.001), but also higher rates of periprocedural major cardiac adverse events compared with MVOs and LVOs (3.08% vs 2.71% vs 1.50%; P&lt;.01). On multivariable analyses, HVOs and MVOs were associated with higher technical success. In a contemporary, multicenter registry, 40% of CTO-PCI cases are performed by LVOs performing &lt;30 cases per year. Cases performed by HVOs were associated with higher technical and procedural success, but also higher periprocedural major complication rates, potentially due to higher lesion complexity.

TCTAP A-036 Annual Operator Volume Among Patients Treated Using Percutaneous Coronary Interventions With Rotational Atherectomy and Procedural Outcomes - Analysis Based on a Large National Registry

TCTAP A-036 Annual Operator Volume Among Patients Treated Using Percutaneous Coronary Interventions With Rotational Atherectomy and Procedural Outcomes - Analysis Based on a Large National Registry

Annual operator volume among patients treated using percutaneous coronary interventions with rotational atherectomy and procedural outcomes: Analysis based on a large national registry.

Low operator and institutional volume are associated with poorer procedural and long-term clinical outcomes in the general population of patients treated with percutaneous coronary interventions (PCI). To assess the relationship between operator experience and procedural outcomes of patients treated with PCI and rotational atherectomy (RA). Data for conducting the current analysis were obtained from the national registry of percutaneous coronary interventions (ORPKI) maintained in cooperation with the Association of Cardiovascular Interventions (AISN) of the Polish Cardiac Society. The study covers data from January 2014 to December 2020. During the investigated period, there were 162 active CathLabs, at which 747,033 PCI procedures were performed by 851 operators (377 RA operators [44.3%]). Of those, 5188 were PCI with RA procedures; average 30 ± 61 per site/7 years (Me: 3; Q1-Q3: 0-31); 6 ± 18 per operator/7 years (Me: 0; Q1-Q3: 0-3). Considering the number of RA procedures annually performed by individual operators during the analyzed 7 years, the first quartile totaled (Q1: < =2.57), the second (Q2: < =5.57), and the third (Q3: < =11.57), while the fourth quartile was (Q4: > 11.57). The maximum number of procedures was 39.86 annually per operator. We demonstrated, through a nonlinear relationship with annualized operator volume and risk-adjusted, that operators performing more PCI with RA per year (fourth quartile) have a lower number of the overall periprocedural complications (p = 0.019). High-volume RA operators are related to lower overall periprocedural complication occurrence in patients treated with RA in comparison to low-volume operators.

TAVR operator volumes, trends, and geographic variations amongst Medicare beneficiaries in the United States.

To evaluate transcatheter aortic valve replacement (TAVR) operator procedural volumes, and describe temporal and geographic trends. TAVR is the standard of care for most patients with severe symptomatic aortic stenosis. Despite an association between operator procedural volume and outcomes, nationwide TAVR operator volumes have been incompletely described. We queried the National Medicare Provider Utilization and Payment Database for transfemoral TAVRs from 2014 to 2018. Annual operator volume, state and regional volumes, and longitudinal trends were extracted and analyzed using descriptive statistics. In 2018, the mean annual operator volume was 23.6 TAVRs. The highest 1% of operators by volume performed 7.6% of total TAVR procedures in the United States, while 35.7% of operators performed 10 or fewer TAVRs per year. From 2014 to 2018, there was a 53.9% annualized increase in TAVRs, and the mean annual volume per operator grew from 12.5 to 23.6. There was more than five-fold variability in the density of operators (range 0.35-1.79 operators per 100,000 population) and mean operator volume by state (range 14.2-52.4 TAVRs per operator). In this nationally representative study of operators performing transfemoral TAVRs among Medicare patients, we found the mean annual volume of TAVR in 2018 to be 23.6 and has increased since 2014. There was considerable variability in operator density and procedural volumes, with a significant proportion of operators performing 10 or fewer TAVRs per year. Ambiguity remains in regard to the optimal balance of procedural requirements to sustain high efficacy outcomes and ensure critical access to TAVR therapies.

Higher Annual Operator Volume Is Associated With Better Reperfusion Rates in Stroke Patients Treated by Mechanical Thrombectomy: The ETIS Registry

ObjectivesThe aim of this study was to determine whether individual operator characteristics have an impact on reperfusion and procedural complication rates. BackgroundMechanical thrombectomy (MT) is a Level IA treatment in acute ischemic stroke (AIS) patients. The operator’s effect has been found to be an independent predictor for clinical outcome and technical performance in interventional cardiology. MethodsFrom the ETIS (Endovascular Treatment in Ischemic Stroke) study, a prospective, multicenter, observational real-world MT registry, the authors included all AIS patients consecutively treated by MT between January 2012 and March 2017 in 3 high-volume comprehensive stroke centers by 19 operators. We assessed the effect of individual operator characteristics on successful reperfusion, defined as modified Thrombolysis In Cerebral Infarction 2b/3 at the end of MT, and procedural complications using multivariable hierarchical logistic regression models. ResultsA total of 1,541 patients with anterior and posterior AIS were enrolled (mean age 67 years; median NIHSS 16). There was a significant operator effect on successful reperfusion, with an intraclass correlation coefficient of 0.036 (p = 0.046), but not on complications (intraclass correlation coefficient = 0). There was a dose–response relationship between annual operator volume and successful reperfusion rate (p = 0.003) with an adjusted odds ratio for successful reperfusion equal to 2.52 (95% confidence interval: 1.37 to 4.64) for patients treated by an operator with an annual volume ≥40 MT/year compared with those treated by an operator with <14 MT/year (first tertile). Nevertheless, this result did not translate to better clinical outcomes. ConclusionsOur data suggest that operator volume of MT/year has a positive impact on successful reperfusion in AIS patients, but not on clinical outcomes nor on complication rates. Further studies are warranted to investigate threshold procedure numbers associated with better outcomes.

3292Lower annual operator volume is associated with higher risk of early cardiac implantable electronic device infection: insights from a contemporary, nationwide Danish cohort

3292Lower annual operator volume is associated with higher risk of early cardiac implantable electronic device infection: insights from a contemporary, nationwide Danish cohort

Trials and Frontiers in Carotid Endarterectomy and Stenting.

Based on the strength of randomized trials from the 1990s, major societal guidelines recommend carotid endarterectomy (CEA) for severe (≥70%), symptomatic carotid stenosis if an operative stroke/death rate of <6% can be maintained (history and major trials in carotid revascularization are summarized in the online-only Data Supplement).1–4 Though the benefit is less evident, most guidelines also recommend consideration of CEA for 50% to 69% symptomatic stenosis.2–4 There are subtle differences in recommendations regarding carotid artery stenting (CAS) in symptomatic patients. Some guidelines stipulate that CEA should be preferred over CAS in patients with severe (≥70%) symptomatic carotid stenosis,2,5 especially if >70 years old,4 whereas others position CAS as an alternative.1,3 Though the risk of operative stroke/death is higher with CAS, major randomized clinical trials (RCTs) report event rates under the recommended 6% cutoff for both treatment modalities. Regarding asymptomatic disease, CEA is recommended for patients with stenosis ≥60% to 70% in highly selected patients as long as operative stroke/death rates <3% can be maintained.1 A predicted life expectancy of at least 3 to 5 years has also been suggested.2 The 3% threshold has been easily met by CEA cohorts in the CREST (Carotid Revascularization Endarterectomy Versus Stenting Trial; 1.4%)6 and the ACT1 (Asymptomatic Carotid Trial; 1.7%),7 suggesting that an even lower threshold may be appropriate. Controversially, some guidelines have recommended that CAS can be considered in highly selected patients with asymptomatic carotid stenosis ≥60% to 70%,1,4,8 whereas others argue that the evidence remains insufficient.2 The lack of consensus in the management of asymptomatic carotid stenosis is reflective of an ongoing need for high-quality RCT data to guide practice. ### CEA Operative Stroke Risk and High Risk Designation Most clinical trials in carotid revascularization have focused …

Association between operator specialty and outcomes after carotid artery revascularization

ObjectiveTo examine the association between operator specialty and 30-day outcomes among patients undergoing carotid endarterectomy and carotid artery stenting. MethodsWe conducted a population-based, observational cohort study of all individuals who underwent carotid endarterectomy or stenting in Ontario, Canada (population, 13.6 million) between April 1, 2002, and March 1, 2015, using administrative claims databases. We stratified endarterectomy and stenting patients according to operator specialty, and followed them for 30 days after the procedure. For carotid endarterectomy, we compared outcomes between vascular surgeons and nonvascular surgeons. For carotid artery stenting, we compared outcomes between radiologists and neurosurgeons. We built multilevel multivariable logistic regression models adjusted for patient demographics, comorbidities, carotid artery symptom status, and annual institutional and operator volume to examine rates of 30-day stroke or death. ResultsA total of 16,544 patients were studied (n = 14,301 endarterectomy and n = 2243 stenting). Vascular surgeons performed the majority (55.7%) of carotid endarterectomy procedures, followed by neurosurgeons (21.0%), general surgeons (15.3%), and cardiac surgeons (7.9%). Radiologists (82.5%) and neurosurgeons (17.5%) performed carotid artery stenting. In the endarterectomy group, the risk of stroke or death was higher among patients treated by nonvascular surgeons (4.0%) compared with vascular surgeons (2.9%; adjusted odds ratio [OR], 1.32; 95% confidence interval [CI], 1.08-1.62; P = .008). This difference was driven by a higher rate of stroke among nonvascular surgery-treated patients (3.6%) compared with vascular surgery-treated patients (2.5%; adjusted OR, 1.38; 95% CI, 1.11-1.71). The risk of death was similar between the two groups. With respect to specific nonvascular surgery specialties, the rate of 30-day stroke or death was higher in endarterectomy patients treated by neurosurgeons (4.1%; adjusted OR, 1.27; 95% CI, 1.00-1.61) and cardiac surgeons (4.4%; adjusted OR, 1.54; 95% CI, 1.04-2.30) compared with vascular surgeons (2.9%). Patients who underwent carotid artery stenting by radiologists vs neurosurgeons experienced 30-day stroke or death at similar rates (8.0% vs 7.9%, respectively; adjusted OR, 1.07; 95% CI, 0.66-1.74; P = .79). ConclusionsThe risk for periprocedural stroke or death was significantly higher among carotid endarterectomy patients treated by nonvascular surgeons (neurosurgeons and cardiac surgeons) compared with vascular surgeons. Operator specialty did not seem to have a significant effect on periprocedural outcomes among patients who underwent carotid artery stenting. These results can have implications for physician referral practices and local policies.

Impact of Institutional and Operator Volume on Short-Term Outcomes of Percutaneous Coronary Intervention: A Report From the Japanese Nationwide Registry

ObjectivesThe aim of this study was to assess the volume–outcome relationship for PCI within the nationwide registration system in Japan. BackgroundThe effect of site and operator case load for percutaneous coronary intervention (PCI) on outcomes has not been investigated thoroughly in non-Western regions. MethodsIn the present study, PCI procedural data recorded between January 2014 and December 2015 in the Japanese PCI registry, a nationwide registration system, were analyzed. Institutions and operators were categorized into deciles based on the number of PCIs performed per year. Odds ratios (ORs) for in-hospital mortality and the composite endpoint (in-hospital death and periprocedural complications) were estimated for each decile (with the lowest volume group as a reference group). ResultsA total of 323,322 PCIs (at 625 hospitals [median PCI cases/year: 216; quartiles: 121 to 332] by 4,211 operators [median PCI cases/year: 28; quartiles: 10 to 56]) were analyzed, of which 2,959 patients (0.9%) and 7,205 patients (2.2%) experienced in-hospital mortality and the composite endpoint after PCI, respectively. The adjusted risk for in-hospital mortality and the composite endpoint was significantly higher in hospitals included in the lowest decile (<150 PCIs/year); the risk remained consistently low across the remaining deciles. Contrastingly, no significant volume–outcome relationship was observed between operator volume and outcomes. A similar trend was observed when the analysis was confined to emergency/urgent PCI cases. ConclusionsIn contemporary Japanese PCI practice, lower institutional volume was related inversely to in-hospital outcomes, but the association of annual operator volume with outcomes was less clear.

Circulation : Clinical Summaries

<i>Circulation</i> : Clinical Summaries

Impact of annual operator and institutional volume on percutaneous coronary intervention outcomes: a 5-year United States experience (2005-2009).

The relationship between operator or institutional volume and outcomes among patients undergoing percutaneous coronary interventions (PCI) is unclear. Cross-sectional study based on the Healthcare Cost and Utilization Project's Nationwide Inpatient Sample between 2005 to 2009. Subjects were identified by International Classification of Diseases, 9(th) Revision, Clinical Modification procedure code, 36.06 and 36.07. Annual operator and institutional volumes were calculated using unique identification numbers and then divided into quartiles. Three-level hierarchical multivariate mixed models were created. The primary outcome was in-hospital mortality; secondary outcome was a composite of in-hospital mortality and peri-procedural complications. A total of 457,498 PCIs were identified representing a total of 2,243,209 PCIs performed in the United States during the study period. In-hospital, all-cause mortality was 1.08%, and the overall complication rate was 7.10%. The primary and secondary outcomes of procedures performed by operators in 4(th) [annual procedural volume; primary and secondary outcomes] [>100; 0.59% and 5.51%], 3(rd) [45-100; 0.87% and 6.40%], and 2(nd) quartile [16-44; 1.15% and 7.75%] were significantly less (P<0.001) when compared with those by operators in the 1(st) quartile [≤15; 1.68% and 10.91%]. Spline analysis also showed significant operator and institutional volume outcome relationship. Similarly operators in the higher quartiles witnessed a significant reduction in length of hospital stay and cost of hospitalization (P<0.001). Overall in-hospital mortality after PCI was low. An increase in operator and institutional volume of PCI was found to be associated with a decrease in adverse outcomes, length of hospital stay, and cost of hospitalization.

Select Articles Published on the Topic of Arrhythmia and Electrophysiogy in 2013

Select Articles Published on the Topic of Arrhythmia and Electrophysiogy in 2013

In-Hospital Complications Associated With Catheter Ablation of Atrial Fibrillation in the United States Between 2000 and 2010

Background— Atrial fibrillation ablation has made tremendous progress with respect to innovation, efficacy, and safety. However, limited data exist regarding the burden and trends in adverse outcomes arising from this procedure. The aim of our study was to examine the frequency of adverse events attributable to atrial fibrillation (AF) ablation and the influence of operator and hospital volume on outcomes. Methods and Results— With the use of the Nationwide Inpatient Sample, we identified AF patients treated with catheter ablation. We investigated common complications including cardiac perforation and tamponade, pneumothorax, stroke, transient ischemic attack, vascular access complications (hemorrhage/hematoma, vascular complications requiring surgical repair, and accidental arterial puncture), and in-hospital death described with AF ablation, and we defined these complications by using validated International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis codes. An estimated 93 801 AF ablations were performed from 2000 to 2010. The overall frequency of complications was 6.29% with combined cardiac complications (2.54%) being the most frequent. Cardiac complications were followed by vascular complications (1.53%), respiratory complications (1.3%), and neurological complications (1.02%). The in-hospital mortality was 0.46%. Annual operator (&lt;25 procedures) and hospital volume (&lt;50 procedures) were significantly associated with adverse outcomes. There was a small (nonsignificant) rise in overall complication rates. Conclusions— The overall complication rate was 6.29% in patients undergoing AF ablation. There was a significant association between operator and hospital volume and adverse outcomes. This suggests a need for future research into identifying the safety measures in AF ablations and instituting appropriate interventions to improve overall AF ablation outcomes.

Abstract 331: Effect of Operator and Hospital Experience on Mortality for Balloon Aortic Valvuloplasty

Background: Utilization of balloon aortic valvulopasty (BAV) has increased in recent years. We aimed to explore the relationship between hospital and operator experience on mortality. Methods: We queried Healthcare Cost and Utilization Project’s Nationwide Inpatient Sample (NIS) between 1998 and 2010 using the ICD9 procedure code of 35.96 for valvuloplasty. The NIS represents 20% of all hospitals in the US. Patients with age &gt; 60years with aortic stenosis were included and those with concomitant mitral, tricuspid or pulmonic stenosis were excluded. Severity of co-morbid conditions was defined with Deyo modification of Charlson’s comorbidity index. Primary outcome was in-hospital mortality. Annual operator and hospital procedure volume were calculated based on the unique operator and hospital identification numbers and were split into tertiles of the total volume per year. Mixed effects logistic regression modeling incorporating hospital ID as random effects was constructed to find out the independent predictors of in-hospital mortality. Results: A total of 2,127 BAV (weighted n= 9,686) were identified for hospital volume analysis and 1,030 BAV (weighted n = 5,125) were available for both operator and hospital volume analysis. In models incorporating either operator or hospital volume alone (hazard ratio (HR), 95% CI, p value) both operator volume (HR 0.5 per every unit increase in operator volume, 0.3-0.9, p&lt;0.05) and hospital volume (0.8 per every 10 unit increase in hospital volume, 0.8-0.9, p &lt;0.05) were independently associated with decreased mortality. However in a model incorporating both operator and hospital volume, only increasing operator volume was associated with decreased mortality (0.85, 0.73-0.98, p=0.03) and influence of hospital volume was no longer statistically significant. Relative risk reduction of mortality was 51% when BAV was performed in the highest tertile of both hospital and operator volume (p=0.05). Conclusion: We demonstrated that both annual operator and hospital procedure volume significantly impact in-hospital mortality for BAV, with operator volume playing a more significant role.

Operator Experience and Carotid Stenting Outcomes in Medicare Beneficiaries

Although the efficacy of carotid stenting has been established in clinical trials, outcomes of the procedure based on operator experience are less certain in clinical practice. To assess association between outcomes and 2 measures of operator experience: annual volume and experience at the time of the procedure among new operators who first performed carotid stenting after a national coverage decision by the Centers for Medicare & Medicaid Services (CMS). Observational study using administrative data on fee-for-service Medicare beneficiaries aged 65 years or older undergoing carotid stenting between 2005 and 2007. Thirty-day mortality stratified by very low, low, medium, and high annual operator volumes (<6, 6-11, 12-23, and ≥24 procedures per year, respectively) and treatment early vs late during a new operator's experience (1st to 11th procedure and 12th procedure or higher). During the study period, 24,701 procedures were performed by 2339 operators. Of these, 11,846 were performed by 1792 new operators who first performed carotid stenting after the CMS national coverage decision. Overall, 30-day mortality was 1.9% (n = 461) and rate of failure to use an embolic protection device was 4.8% (n = 1173). The median annual operator volume among Medicare beneficiaries was 3.0 per year (interquartile range, 1.4-6.5) and 11.6% of operators performed 12 or more procedures per year during the study period. Observed 30-day mortality was higher among patients treated by operators with lower annual volumes (2.5% [95% CI, 2.1%-2.9%], 1.9% [95% CI, 1.6%-2.3%], 1.6% [95% CI, 1.3%-1.9%], and 1.4% [95% CI, 1.1%-1.7%] across the 4 categories; P < .001) and among patients treated early (2.3%; 95% CI, 2.0%-2.7%) vs late (1.4%; 95% CI, 1.1%-1.9%; P < .001) during a new operator's experience. After multivariable adjustment, patients treated by very low-volume operators had a higher risk of 30-day mortality compared with patients treated by high-volume operators (adjusted odds ratio, 1.9; 95% CI, 1.4-2.7; P < .001). Similarly, we found a higher risk of 30-day mortality in patients treated early vs late during a new operator's experience (adjusted odds ratio, 1.7; 95% CI, 1.2-2.4; P = .001). Among older patients undergoing carotid stenting, lower annual operator volume and early experience are associated with increased 30-day mortality.

Operator experience and sample quality in genetic amniocentesis

We sought to relate the frequency of maternal cell contamination in amniotic fluid samples that were submitted to a single laboratory for cytogenetic analysis to the experience and training of the physician who performed the amniocentesis. We reviewed the database of a single cytogenetics laboratory to compare the number of amniocenteses that were performed annually per physician to the rate of maternal cell contamination in genetic amniocentesis samples. Only samples that resulted in a 46 XY male karyotype were studied so that maternal cell contamination could be identified as having occurred when the karyotype revealed > or = 1 cell with 2 X chromosomes. Samples were categorized as being submitted by a physician who submitted > or = 50 or more samples annually versus < 50 samples to this laboratory. The frequency of maternal cell contamination was compared with annual operator volume with 2 x 2 tables and analyzed by chi-squared testing. Between 2000 and 2004, the laboratory received 6332 mid-trimester amniotic fluid samples that generated a male karyotype result. Fourteen of 2081 samples (0.67%) that were submitted by physicians who submitted < 50 samples grew > or = 1 46 XX cells, compared with 8 of 4251 samples (0.19%; chi-squared, 9.47; degrees of freedom, 1; P = .0021). Maternal cell contamination occurs more frequently in genetic amniocentesis samples that are obtained by physicians who perform < 50 genetic amniocenteses annually.

Volume-Outcome Relationships for Percutaneous Coronary Interventions in the Stent Era

Most studies that are the basis of recommended volume thresholds for percutaneous coronary interventions (PCIs) predate the routine use of stent placement. Data from New York's Percutaneous Coronary Interventions Reporting System in 1998 to 2000 (n=107 713) were used to examine the impact of annual hospital volume and annual operator volume on in-hospital mortality, same-day coronary artery bypass graft (CABG) surgery, and same-stay CABG surgery after adjustment for differences in patients' severity of illness. For a hospital-volume threshold of 400, the odds ratios for low-volume hospitals versus high-volume hospitals were 1.98 (95% CI, 1.17, 3.35) for in-hospital mortality, 2.07 (95% CI, 1.36, 3.15) for same-day CABG surgery, and 1.51 (95% CI, 1.03, 2.21) for same-stay CABG surgery. For an operator-volume threshold of 75, the odds ratios for low-volume versus high-volume operators were 1.65 (95% CI, 1.05, 2.60) for same-day CABG surgery and 1.55 (95% CI, 1.10, 2.18) for same-stay CABG surgery. Operator volume was not significantly associated with mortality. Also, for hospital volumes below 400 and operator volumes below 75, the respective odds of mortality, same-day CABG surgery, and same-stay CABG surgery were 5.92, 4.02, and 3.92 times the odds for hospital volumes of 400 or higher and operator volumes of 75 or higher. Higher-volume operators and hospitals continue to experience lower risk-adjusted PCI outcome rates.