Analysis and comparison of operator-specific outcomes in interventional cardiology. From a multicenter database of 4860 quality-controlled procedures

A fitting machine learning prediction model for short-term mortality following percutaneous catheterization intervention: a nationwide population-based study

BACKGROUND

A suitable multivariate predictor for predicting mortality following percutaneous coronary intervention (PCI) remains undetermined. We used a nationwide database to construct mortality prediction models to find the appropriate model.

METHODS

Data were analyzed from the Taiwan National Health Insurance Research Database (NHIRD) covering the period from 2004 to 2013. The study cohort was composed of 3,421 patients with acute myocardial infarction (AMI) diagnosis undergoing PCI. The dataset of enrolled patients was used to construct multivariate prediction models. Of these, 3,079 and 342 patients were included in the training and test groups, respectively. Each patient had 22 input features and 2 output features that represented mortality. This study implemented an artificial neural network model (ANN), a decision tree (DT), a linear discriminant analysis classifier (LDA), a logistic regression model (LR), a naïve Bayes classifier (NB), and a support vector machine (SVM) to predict post-PCI patient mortality.

RESULTS

The DT model was found to be the most suitable in terms of performance and real-world applicability. The DT model achieved an area under receiving operating characteristic of 0.895 (95% confidence interval: 0.865-0.925), F1 of 0.969, precision of 0.971, and recall of 0.974.

CONCLUSIONS

The DT model constructed using data from the NHIRD exhibited effective 30-day mortality prediction for patients with AMI following PCI.

The association between the public reporting of individual operator outcomes with patient profiles, procedural management, and mortality after percutaneous coronary intervention: an observational study from the Pan-London PCI (BCIS) Registry using an interrupted time series analysis

AIMS

The public reporting of healthcare outcomes has a number of potential benefits; however, unintended consequences may limit its effectiveness as a quality improvement process. We aimed to assess whether the introduction of individual operator specific outcome reporting after percutaneous coronary intervention (PCI) in the UK was associated with a change in patient risk factor profiles, procedural management, or 30-day mortality outcomes in a large cohort of consecutive patients.

METHODS AND RESULTS

This was an observational cohort study of 123 780 consecutive PCI procedures from the Pan-London (UK) PCI registry, from January 2005 to December 2015. Outcomes were compared pre- (2005-11) and post- (2011-15) public reporting including the use of an interrupted time series analysis. Patients treated after public reporting was introduced were older and had more complex medical problems. Despite this, reported in-hospital major adverse cardiovascular and cerebrovascular events rates were significantly lower after the introduction of public reporting (2.3 vs. 2.7%, P < 0.0001). Interrupted time series analysis demonstrated evidence of a reduction in 30-day mortality rates after the introduction of public reporting, which was over and above the existing trend in mortality before the introduction of public outcome reporting (35% decrease relative risk 0.64, 95% confidence interval 0.55-0.77; P < 0.0001).

CONCLUSION

The introduction of public reporting has been associated with an improvement in outcomes after PCI in this data set, without evidence of risk-averse behaviour. However, the lower reported complication rates might suggest a change in operator behaviour and decision-making confirming the need for continued surveillance of the impact of public reporting on outcomes and operator behaviour.

Angiographic Lesion Complexity Score and In-Hospital Outcomes after Percutaneous Coronary Intervention

OBJECTIVE

We devised a percutaneous coronary intervention (PCI) scoring system based on angiographic lesion complexity and assessed its association with in-hospital complications.

BACKGROUND

Although PCI is finding increasing application in patients with coronary artery disease, lesion complexity can lead to in-hospital complications.

METHODS

Data from 3692 PCI patients were scored based on lesion complexity, defined by bifurcation, chronic total occlusion, type C, and left main lesion, along with acute thrombus in the presence of ST-segment elevation myocardial infarction (1 point assigned for each variable).

RESULTS

The patients' mean age was 67.5 +/- 10.8 years; 79.8% were male. About half of the patients (50.3%) presented with an acute coronary syndrome, and 2218 (60.1%) underwent PCI for at least one complex lesion. The patients in the higher-risk score groups were older (p < 0.001) and had present or previous heart failure (p = 0.02 and p = 0.01, respectively). Higher-risk score groups had significantly higher in-hospital event rates for death, heart failure, and cardiogenic shock (from 0 to 4 risk score; 1.7%, 4.5%, 6.3%, 7.1%, 40%, p < 0.001); bleeding with a hemoglobin decrease of >3.0 g/dL (3.1%, 11.0%, 13.1%, 10.3%, 28.6%, p < 0.001); and postoperative myocardial infarction (1.5%, 3.1%, 3.8%, 3.8%, 10%, p = 0.004), respectively. The association with adverse outcomes persisted after adjustment for known clinical predictors (odds ratio 1.72, p < 0.001).

CONCLUSION

The complexity score was cumulatively associated with in-hospital mortality and complication rate and could be used for event prediction in PCI patients.

Prognostic value of angiographic lesion complexity in patients with acute coronary syndromes undergoing percutaneous coronary intervention (from the acute catheterization and urgent intervention triage strategy trial)

Although lesion complexity is predictive of outcomes after balloon angioplasty, it is unclear whether complex lesions continue to portend a worse prognosis in patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI) with contemporary interventional therapies. We sought to assess the impact of angiographic lesion complexity, defined by the modified American College of Cardiology/American Heart Association classification, on clinical outcomes after PCI in patients with ACS and to determine whether an interaction exists between lesion complexity and antithrombin regimen outcomes after PCI. Among the 3,661 patients who underwent PCI in the Acute Catheterization and Urgent Intervention Triage strategy study, patients with type C lesions (n = 1,654 [45%]) had higher 30-day rates of mortality (1.2% vs 0.6%, p = 0.049), myocardial infarction (9.2% vs 6.3%, p = 0.0006), and unplanned revascularization (4.3% vs 3.1%, p = 0.04) compared with those without type C lesions. In multivariate analysis, type C lesions were independently associated with myocardial infarction (odds ratio [95% confidence interval] = 1.37 [1.04 to 1.80], p = 0.02) and composite ischemia (odds ratio [95% confidence interval] = 1.49 [1.17 to 1.88], p = 0.001) at 30 days. Bivalirudin monotherapy compared with heparin plus a glycoprotein IIb/IIIa inhibitor reduced major bleeding complications with similar rates of composite ischemic events, regardless of the presence of type C lesions. There were no interactions between antithrombotic regimens and lesion complexity in terms of composite ischemia and major bleeding (p [interaction] = 0.91 and 0.80, respectively). In conclusion, patients with ACS with type C lesion characteristics undergoing PCI have an adverse short-term prognosis. Treatment with bivalirudin monotherapy reduces major hemorrhagic complications irrespective of lesion complexity with comparable suppression of adverse ischemic events as heparin plus glycoprotein IIb/IIIa inhibitor.

A multicenter, prospective, advanced diagnostic bronchoscopy outcomes registry

BACKGROUND

Multiple new diagnostic bronchoscopic technologies are available, but little is known about their comparative performance and specific yield when adjusted for location of lesions, target size, and diagnosis. We present a multi-institutional prospective-outcomes database to assess diagnostic yields of advanced bronchoscopic procedures, as well as related morbidity and mortality.

METHODS

Data were extracted and reviewed from an ongoing, paper-based, prospective, multi-institutional outcomes database for advanced diagnostic bronchoscopic procedures. All consecutive eligible patients are entered into this database, and information on demographics, procedure, and lesion characteristics as well as complications were documented. Descriptive statistical analyses were performed.

RESULTS

A total of 310 diagnostic procedures were performed over a 1-year period in four institutions by 15 different clinicians. The majority of the patients were white (66%), male (56%), former smokers (55%), with a mean age of 61 +/- 14 years. The average procedure time was 36 min, and the most common procedure was transbronchial needle aspiration (TBNA) (n = 198). Nodal tissue was obtained in 82.3% from TBNA sampling with a mean of three passes using endobronchial ultrasound guidance with a 22-gauge needle and mostly without on-site cytology. The overall diagnostic yield for all procedures was 75%. There were few complications, and none required a change in disposition.

CONCLUSIONS

Prospective and ongoing data analysis for bronchoscopic procedures is feasible and valuable. Lesion-adjusted diagnostic yields can be documented and potentially used for comparative assessment of different technologies and operators, as well as benchmarking and quality improvement initiatives. Extending the number of participating centers and web-based submission to minimize missing data components are the next, already-initiated steps.

Operator volume and outcomes of primary angioplasty for acute myocardial infarction in a single high-volume centre

OBJECTIVE

The guidelines for the management of ST-elevation myocardial infarction (STEMI) state the minimum operator volume for percutaneous coronary interventions (PCIs), without strong evidence of a relationship between operator volume and outcomes of primary angioplasty, at variance with elective practice. We sought to investigate the effect of operator volume on primary PCI for STEMI.

METHODS

Three hundred and thirty-one consecutive STEMI patients were treated over 19 months with primary PCI in a high-volume centre without on-site cardiac surgery. Three skilled operators, with very different volumes of interventional practice, performed the PCI procedures around-the-clock.

RESULTS

Operators were divided into very high (A), intermediate high (B) and low high volume (C). Demographic, clinical, angiographic, and procedural characteristics of the patient population did not differ among operators, with the exception of three-vessel disease (P = 0.016), circumflex infarct-related artery (P = 0.002), mechanical support (P = 0.02), use of abciximab (P = 0.003) for operator C, use of tirofiban for operator B (P = 0.02), and type of stent for operator A (P = 0.0004). Similarly, no differences were observed among operators in in-hospital outcomes (death, a composite of major adverse cardiovascular events, ST-segment resolution, thrombolysis in myocardial infarction flow grade 3, length of hospitalization) and haemorrhagic complications.

CONCLUSIONS

Our data show that there is not a significant relationship between operator volume over the threshold indicated by the guidelines, and both primary PCI early outcomes and complications in STEMI, and suggest that expertise and experience of the whole professional team rather than just of the individual operator play a major role.

Physician volume, physician specialty and in-hospital mortality for patients with acute myocardial infarction

This study sets out to assess the relationship between in-hospital mortality rates and physician acute myocardial infarction (AMI) volume, along with an examination of the impact of physician specialty on in-hospital mortality rates in Taiwan. Analysis was undertaken on a total of 19,086 patients hospitalized for AMI, following the division of the sample patients into four roughly equivalent groups. Within each physician specialty, the AMI patients were also subsequently grouped into four roughly equivalent groups based upon physician volume. After adjusting for other factors, the likelihood of in-hospital mortality among patients treated by low-volume physicians was 2.141 (p<0.001) times as high as that for patients treated by high-volume physicians, and 2.410 (p<0.001) times as high as that for patients treated by very high-volume physicians. However, while such an inverse relationship was found to persist for those physicians specializing in general internal medicine and 'others', this was not the case for cardiologists.

Selection tool for foodborne norovirus outbreaks

Surveillance data provided a practical tool, which prospectively selects potential food-related norovirus outbreaks.

Detection of pathogens in the food chain is limited mainly to bacteria, and the globalization of the food industry enables international viral foodborne outbreaks to occur. Outbreaks from 2002 through 2006 recorded in a European norovirus surveillance database were investigated for virologic and epidemiologic indicators of food relatedness. The resulting validated multivariate logistic regression model comparing foodborne (n = 224) and person-to-person (n = 654) outbreaks was used to create a practical web-based tool that can be limited to epidemiologic parameters for nongenotyping countries. Non–genogroup-II.4 outbreaks, higher numbers of cases, and outbreaks in restaurants or households characterized (sensitivity = 0.80, specificity = 0.86) foodborne outbreaks and reduced the percentage of outbreaks requiring source-tracing to 31%. The selection tool enabled prospectively focused follow-up. Use of this tool is likely to improve data quality and strain typing in current surveillance systems, which is necessary for identification of potential international foodborne outbreaks.

Prospective risk-adjusted morbidity and mortality outcome analysis after therapeutic bronchoscopic procedures: results of a multi-institutional outcomes database

INTRODUCTION

Interest in databases is growing to allow for outcomes research, assess health-care quality, and determine best practices and resource allocation, and they are increasingly considered as a tool to potentially tie reimbursement to outcome parameters. Little is known about resource use and risk-adjusted morbidity and mortality after therapeutic bronchoscopic interventions.

METHODS

Data were extracted and reviewed from an ongoing prospective, multi-institutional outcomes database for therapeutic bronchoscopic interventions. All consecutive patients are entered into this database, and information on demographics, indications, procedures and anesthesia, comorbidities and general health status, urgency of intervention, morbidity and mortality to 30 days, increase in levels of care, and procedural resources is documented.

RESULTS

From December 2005 to May 2007, 554 therapeutic procedures were performed in four hospitals. Most procedures were done under general anesthesia (n = 362) and rigid bronchoscopy (n = 483), and the most common intervention was airway stent placement (n = 258). Forty-two percent of procedures were done urgently or emergently. Complications were common (19.8%), and 30-day mortality was 7.8%, correlating with underlying health status and urgency of intervention.

DISCUSSION

Prospective and ongoing data analysis for bronchoscopic procedures is feasible and valuable. Risk-adjusted and disease-specific outcomes can be documented and potentially used for quality assessment, benchmarking, and quality improvement initiatives. Appropriate use of resources and effect of interventions can be documented. Extending the number of participating centers as well as inclusion of quality of life tools and technical success are the next steps.

Coronary perforation during percutaneous coronary intervention

Coronary perforation is an undesirable complication during percutaneous coronary intervention (PCI). We reviewed the cases of overt coronary perforation in our institute and analyzed their clinical backgrounds, the characteristics of the target lesion, management, and clinical outcomes. Between 1991 and 2005, we experienced 12 cases (0.35%) of coronary perforation in a total of 3415 PCI procedures. The perforation occurred during the use of debulking devices in 3 cases, immediately after stenting in 2, immediately after postdilatation of the stent in 2, and during wiring in 3 cases. Restoration was attempted by long inflation of a balloon in 7 cases, implantation of a covered stent graft in 1, and emergency surgical repair in 1 case. Subsequent cardiac tamponade occurred in 3 patients who required pericardiocentesis, and 1 patient died due to congestive heart failure. Administration of protamine was effective in stopping the bleeding in 6 patients, whereas continuation of antiplatelet therapy resulted in no overt rebleeding. Coronary perforation during PCI is a rare complication but is associated with significant morbidity and mortality. Intravenous administration of protamine is effective when it is used in conjunction with nonsurgical devices for initial management of perforation.

Quality Management and Volume-Related Outcomes in the Cardiac Catheterization Laboratory

The assessment of quality in the cardiac catheterization laboratory is a complex, ongoing process that requires a comprehensive analysis of the multiple elements of quality. Although clinical outcomes are a reflection of the quality process, they derive from a complex interaction of clinical, technical, and process-of-care components. Procedural volume is associated but not equated with clinical outcomes, although the magnitude of this association depends on numerous covariates, most notably the diminishing rate of adverse outcomes over time.

Impedance cardiography as a noninvasive technique for atrioventricular interval optimization in cardiac resynchronization therapy

INTRODUCTION

Impedance cardiography (IC) and Doppler echocardiography (DE) are two noninvasive methods to evaluate hemodynamics in patients with dual-chamber pacemakers. The aim of the present study was to compare both techniques in respect to their ability of AV-interval optimization in cardiac resynchronization therapy (CRT) based on cardiac output (CO) measurements.

METHODS AND RESULTS

Twenty-four patients (64 +/- 8 years) with congestive heart failure (EF<35%; NYHA III-IV) and LBBB (>150 ms) were evaluated at baseline and 1 month after implantation of a CRT-D. The optimal AV interval was defined by IC and subsequently by transaortic flow DE as the interval corresponding to the highest CO measured at different AV intervals, varying from 60 to 200 ms (with 20 ms increments). For standardization and comparison of both techniques, a fixed atriobiventricular pacing rate of 90 beats/min was used. Absolute values of COmax were higher by IC (5.8+/-0.9 l/min) as compared to DE (4.6 +/- 0.9 l/min, p < 0.01). The optimal AV interval as determined by IC varied interindividually from 80-180 ms (mean: 121+/-18 ms). In DE, the range was also 80-180 ms with the mean optimal AV interval of 128+/-23 ms. Thus, there was a strong correlation for AV-interval optimization in CRT between both methods (r=0.74; p<0.001).

CONCLUSION

In CRT, AV-interval optimization based on CO values determined by IC correlates closely to those measured by transaortic flow DE. Impedance cardiography as an easy and cost-effective technique for AV-interval optimization is a promising alternative for routine management of heart failure patients on a beat-to-beat analysis during CRT follow-up.

Importance of the postdischarge interval in assessing major adverse clinical event rates following percutaneous coronary intervention

In-hospital major adverse clinical event (MACE) rates after percutaneous coronary intervention serve as benchmarks of performance. However, accelerated clinical pathways, decreased lengths of stay, and potential delayed effects of percutaneous coronary intervention may result in an underestimation of this traditional measurement of outcome. Records from patients in the first 3 waves of the National Heart, Lung, and Blood Institute's Dynamic Registry (n = 6,676) were reviewed for rates of composite in-hospital MACEs (death, myocardial infarction, and any repeat target vessel revascularization) and postdischarge MACEs (death, myocardial infarction, repeat hospitalization, and repeat target vessel revascularization) through 30 days. Rates for each composite MACE were compared across waves to assess changes over time. Predictors of each MACE category were identified using multivariate analysis. In-hospital MACE decreased significantly (5.4% of wave 1, 4.9% of wave 2, 3.1% of wave 3, p <0.001), whereas stent implantation increased significantly (67.5% of wave 1, 79.1% of wave 2, 86.2% of wave 3, p <0.001). Postdischarge MACE through 30 days remained unchanged (5.1% of wave 1, 5.1% of wave 2, 4.8% of wave 3, p = 0.6). Mean length of stay decreased (2.7 days for wave 1, 2.2 days for wave 3, p <0.001). Disparate clinical, procedural, and angiographic factors were associated with each MACE. Postdischarge MACE rates through 30 days comprise a significant and unchanging fraction of overall procedurally related MACE rates despite improving in-hospital outcomes. Most postdischarge events derive from pathology related to the controlled vessel. A 30-day MACE rate may serve as a more comprehensive measurement of procedural outcome.

Comparison of a silicon carbide coated stent versus a noncoated stent in humans: the Tenax- versus Nir-Stent Study (TENISS)

PURPOSE

Stents coated with hypothrombogenic silicon carbide (a-SiC:H) exhibited low restenosis rates in the rabbit and in an observational study in humans. Thus, the clinical and angiographic outcome was assessed in a large multicenter study.

MATERIAL AND METHODS

Four hundred and ninety-seven patients (63.4 +/- 9.8 years) were randomized to either receive the a-SiC:H-coated Tenax stent or the stainless steel Nir stent. Lesions (diameter > or = 2.8 mm, length < 20 mm) were covered with one single stent.

RESULTS

Fifty-one of 497 (10.3%) patients were excluded for protocol violation. Three hundred and forty-two of 446 (76.7%) patients presented for scheduled angiographic follow-up after 4.7 +/- 1.2 months and 29 of 446 (6.5%) prematurely. In-hospital complications comprised two deaths (0.8%) (P > 0.99) and one (0.4%) (P > 0.99) CK-elevation in each group, target lesion revascularization in 5 of 250 (2%) of the Tenax and 4 of 244 (1.6%) of the Nir sample (P > 0.99), and subacute thrombosis in 2 of 250 (0.8%) of the Tenax patients (P = 0.5). In the Tenax/Nir patients mean percent diameter stenosis decreased from 82.3 +/- 9.1%/80.7 +/- 8.4% (P = 0.49) to 17.6 +/- 5.5%/17.6 +/- 5.5% (P = 0.99) postprocedure and increased to 34.5 +/- 21.5%/34.2 +/- 23.1% (P = 0.90) at follow-up.

CONCLUSIONS

Thus, there appears to be no advantage of the silicon carbide coated stent over a stainless steel stent after 4.7 +/- 1.2 months with regard to clinical and angiographic restenosis rates.

Volume-Outcome Relation for Hospitals Performing Angioplasty for Acute Myocardial Infarction-Results From the Nationwide Japanese Registry-

BACKGROUND

The purpose of this study was to use a contemporary database to examine the relationship between annual hospital volume and the outcomes of percutaneous coronary interventions (PCIs) for acute myocardial infarction (AMI), given the wide spread use of coronary stents. An inverse relation exists between the number of PCIs and short-term outcome, but PCI practice has been changing with the availability of new devices such as stents.

METHODS AND RESULTS

Data from the 1997 Japanese nationwide registry were analyzed to determine the relation between the annual hospital volume of PCI procedures for patients with AMI and in-hospital mortality, as well as the need for coronary artery bypass graft (CABG) surgery. A total of 129 hospitals (2,491 patients) were divided into terciles according to the annual volume. Of the procedures, 39% involved coronary stents. Median annual PCI volumes varied across terciles from low =10, middle =33, and high =89. After adjusting for patient characteristics, there was no significant relationship between volume and in-hospital mortality (trend P=0.66) and CABG (trend P=0.35). Among patients who received stents (n=958), there was no significant association between volume and either mortality or CABG.

CONCLUSIONS

Using the contemporary database, there was no significant relationship between hospital volume and in-hospital outcome among AMI patients undergoing PCIs.

Validation of Mayo clinic risk adjustment model for in-hospital complications after percutaneous coronary interventions, using the National Heart, Lung, and Blood Institute dynamic registry

OBJECTIVES

We sought to validate the recently proposed Mayo Clinic risk score model for complications after percutaneous coronary interventions (PCI), using an independent data set.

BACKGROUND

The Mayo Clinic risk score has eight simple clinical and angiographic variables for the prediction of complications defined as either death, Q-wave myocardial infarction, emergent or urgent coronary artery bypass graft surgery, or cerebrovascular accident after PCI. External validation using an independent data set is lacking.

METHODS

A total of 3,264 patients undergoing PCI at each of the 17 sites in the National Heart, Lung, and Blood Institute's Dynamic Registry during two enrollment periods (July 1997 to February 1998 and February to June 1999) were studied. Logistic regression was used to model the calculated risk score and major procedural complications. The expected number of complications, with 95% confidence bounds (CBs), was also calculated.

RESULTS

There were 96 (2.94%) observed procedural complications, and the Mayo Clinic risk score predicted 93.5 events (2.86%; 95% CB 2.32% to 3.41%; p = NS). The Hosmer-Lemeshow goodness-of-fit p value was 0.28, and the area under the receiver operating curve was 0.76, indicating excellent overall discrimination. There were no statistical differences between observed and predicted procedural complications using the Mayo Clinic risk score among the most selected high- and low-risk subgroups.

CONCLUSIONS

Eight variables were combined into a convenient risk scoring system that accurately predicts cardiovascular complications after PCI. The Mayo clinic predictive model for procedural complications yielded excellent results when applied to a multi-center external data set.

The Blue Cross Blue Shield of Michigan Cardiovascular Consortium (BMC2) collaborative quality improvement initiative in percutaneous coronary interventions

The past decade has been characterized by increased scrutiny of outcomes of surgical and percutaneous coronary interventions (PCIs). This increased scrutiny has led to the development of regional, state, and national databases for outcome assessment and for public reporting. This report describes the initial development of a regional, collaborative, cardiovascular consortium and the progress made so far by this collaborative group. In 1997, a group of hospitals in the state Michigan agreed to create a regional collaborative consortium for the development of a quality improvement program in interventional cardiology. The project included the creation of a comprehensive database of PCIs to be used for risk assessment, feedback on absolute and risk-adjusted outcomes, and sharing of information. To date, information from nearly 20,000 PCIs have been collected. A risk prediction tool for death in the hospital and additional risk prediction tools for other outcomes have been developed from the data collected, and are currently used by the participating centers for risk assessment and for quality improvement. As the project enters into year 5, the participating centers are deeply engaged in the quality improvement phase, and expansion to a total of 17 hospitals with active PCI programs is in process. In conclusion, the Blue Cross Blue Shield of Michigan Cardiovascular Consortium is an example of a regional collaborative effort to assess and improve quality of care and outcomes that overcome the barriers of traditional market and academic competition.

Development of a risk adjustment mortality model using the American College of Cardiology-National Cardiovascular Data Registry (ACC-NCDR) experience: 1998-2000

OBJECTIVES

We sought to develop and evaluate a risk adjustment model for in-hospital mortality following percutaneous coronary intervention (PCI) procedures using data from a large, multi-center registry.

BACKGROUND

The 1998-2000 American College of Cardiology-National Cardiovascular Data Registry (ACC-NCDR) dataset was used to overcome limitations of prior risk-adjustment analyses.

METHODS

Data on 100,253 PCI procedures collected at the ACC-NCDR between January 1, 1998, and September 30, 2000, were analyzed. A training set/test set approach was used. Separate models were developed for presentation with and without acute myocardial infarction (MI) within 24 h.

RESULTS

Factors associated with increased risk of PCI mortality (with odds ratios in parentheses) included cardiogenic shock (8.49), increasing age (2.61 to 11.25), salvage (13.38) urgent (1.78) or emergent PCI (5.75), pre-procedure intra-aortic balloon pump insertion (1.68), decreasing left ventricular ejection fraction (0.87 to 3.93), presentation with acute MI (1.31), diabetes (1.41), renal failure (3.04), chronic lung disease (1.33); treatment approaches including thrombolytic therapy (1.39) and non-stent devices (1.64); and lesion characteristics including left main (2.04), proximal left anterior descending disease (1.97) and Society for Cardiac Angiography and Interventions lesion classification (1.64 to 2.11). Overall, excellent discrimination was achieved (C-index = 0.89) and application of the model to high-risk patient groups demonstrated C-indexes exceeding 0.80. Patient factors were more predictive in the MI model, while lesion and procedural factors were more predictive in the analysis of non-MI patients.

CONCLUSIONS

A risk adjustment model for in-hospital mortality after PCI was successfully developed using a contemporary multi-center registry. This model is an important tool for valid comparison of in-hospital mortality after PCI.

The impact of statistical adjustment on economic profiles of interventional cardiologists

OBJECTIVES

The objective of this study was to identify preprocedure patient factors associated with percutaneous intervention costs and to examine the impact of these patient factors on economic profiles of interventional cardiologists.

BACKGROUND

There is increasing demand for information about comparative resource use patterns of interventional cardiologists. Economic provider profiles, however, often fail to account for patient characteristics.

METHODS

Data were obtained from Duke Medical Center cost and clinical information systems for 1,949 procedures performed by 13 providers between July 1, 1997, and December 31, 1998. Patient factors that influenced cost were identified using multiple regression analysis. After assessing interprovider variation in unadjusted cost, mixed linear models were used to examine how much cost variability was associated with the provider when patient characteristics were taken into account.

RESULTS

Total hospital costs averaged $15,643 (median, $13,809), $6,515 of which represented catheterization laboratory costs. Disease severity, acuity, comorbid illness and lesion type influenced total costs (R(2) = 38%), whereas catheterization costs were affected by lesion type and acuity (R(2) = 32%). Patient characteristics varied significantly among providers. Unadjusted total costs were weakly associated with provider, and this association disappeared after accounting for patient factors. The provider influence on catheterization costs persisted after adjusting for patient characteristics. Furthermore, the pattern of variation changed: the adjusted analysis identified three new outliers, and two providers lost their outlier status. Only one provider was consistently identified as an outlier in the unadjusted and adjusted analyses.

CONCLUSIONS

Economic profiles of interventional cardiologists may be misleading if they do not adequately adjust for patient characteristics before procedure.

Clinical outcome after successful coronary angioplasty: impact of intracoronary stent implantation

The clinical outcome after successful conventional coronary balloon angioplasty is compared with that of stent implantation after 30 days and 12 months. The study took place at the Divisions of Cardiology and Thoracic Radiology, Norrland University Hospital, Umeå, a referral centre for northern Sweden. The first 100 consecutive patients with stable or unstable angina undergoing successful percutaneous transluminal coronary angioplasty (PTCA) in 1994 and the first 100 consecutive patients undergoing successful coronary stent implantation in 1995 were included. The cardiac endpoints studied were death, myocardial infarction, need for repeat PTCA or coronary artery bypass grafting (CABG). Significantly more adverse cardiac events were observed in the PTCA group compared with the stent group. Event-free 12 months' follow-up (no deaths, myocardial infarction or re-intervention) was 64% in the PTCA group and 86% in the stent group (p < 0.005). The main explanation for the observed difference was a reduction in the need for a repeat PTCA (7 vs 18, p < 0.05) or CABG (4 vs 12, p < 0.05) in the stent group. Patients with stable or unstable angina who can be treated with a stent have a better clinical outcome than those treated with coronary balloon angioplasty only.

Comparison of artificial neural networks with logistic regression in prediction of in-hospital death after percutaneous transluminal coronary angioplasty

OBJECTIVES

Our objective was to compare artificial neural networks (ANNs) with logistic regression for prediction of in-hospital death after percutaneous transluminal coronary angioplasty and to assess the impact of guiding initial ANN variable selection with univariate analysis.

BACKGROUND

ANNs can detect complex patterns within data. Criticisms include the unpredictability of variable selection. They have not previously been applied to outcomes modeling for percutaneous coronary interventions.

METHODS

A database of consecutive (n = 3019) percutaneous transluminal coronary angioplasty procedures from an academic tertiary referral center between July 1994 and July 1997 was used. An ANN was developed for 38 variables (unguided model) (n = 1554). A second model was developed with predictors from an univariate analysis (guided model). Both were compared with a logistic regression model developed from the same database. Model validation was performed on independent data (n = 1465). Model predictive accuracy was assessed by the area under receiver operating characteristic curves. Goodness of fit was assessed with the Hosmer-Lemeshow statistic.

RESULTS

Sixty unguided and guided ANNs were developed. Predictive accuracy and model calibration for all models were similar for training data but were significantly better for logistic regression for independent validation data. Overestimation of event rate in higher risk patients accounted for the majority of discrepancy in model calibration for the ANNs. This difference was partially amended by guiding variable selection.

CONCLUSION

ANNs were able to model in-hospital death after percutaneous transluminal coronary angioplasty when guiding variable selection. However, performance was not better than traditional modeling techniques. Further investigations are needed to understand the impact of this methodology on outcomes analysis.

Prediction of death after percutaneous coronary interventional procedures

BACKGROUND

The prediction and comparison of procedural death after percutaneous coronary interventional procedures is inherently difficult because of variations in case mix and practice patterns. The impact of modern, expanded patient selection criteria, and newer technologic approaches is unknown. Our objective was to determine whether a risk equation based on patient-related variables and derived from an independent data set can accurately predict procedural death after percutaneous coronary intervention in the current era.

METHODS AND RESULTS

An analysis was made of the Mayo Clinic Coronary Interventional Database January 1, 1995, to October 31, 1997. Expected mortality rate was calculated with the use of the New York State multivariate risk score. In 3387 patients, 3830 procedures (55.1% stents) were performed, with an expected mortality rate of 2.32% and observed mortality rate of 2.38% (P = not significant). The risk score derived from the New York multivariate model was highly predictive of death (chi-square = 213.8; P <.0001). The presence of a high-risk lesion characteristic such as calcium, thrombus, or type C lesion was modestly associated with death.

CONCLUSIONS

The New York State multivariate model accurately predicted procedural death in our database.

A simplified lesion classification for predicting success and complications of coronary angioplasty. Registry Committee of the Society for Cardiac Angiography and Intervention

In 1988, the American College of Cardiology/American Heart Association (ACC/AHA) Task Force on Assessment of Diagnostic and Therapeutic Cardiovascular Procedures presented a classification of coronary lesions utilizing 26 lesion features to predict the success and complications of balloon angioplasty. Using data from the Registry of the Society for Cardiac Angiography and Interventions (SCAI) we evaluated the ability of this classification to predict success and complications. Lesion success, death in hospital, emergency cardiac bypass surgery, and major adverse events were evaluated in 41,071 patients who underwent single-vessel angioplasty from January 1993 to June 1996. Logistic models using the ACC/AHA lesion classification, vessel patency, or both, were compared. A new classification based on the interaction of the ACC/AHA classification plus lesion patency was compared with the existing ACC/AHA classification. Vessel patency, added to the ACC/AHA classification, improved prediction of lesion success (p </=0.0001). Class A and patent B lesions had similar success and complication rates, so a simplified classification (SCAI) using only 7 lesion characteristics could be created. This system (I: non-C patent, II: C patent, III: non-C occluded, and IV: C occluded) improved prediction of lesion success compared with the ACC/AHA classification (Bayesian Information Criterion statistic: ACC/AHA 16539, SCAI 15956; and area under the receiver- operating characteristics curve 0.659, 0.693, respectively). The SCAI classification was preferred for predicting major complications and in-hospital death and was similar to the ACC/AHA classification for predicting emergency bypass surgery.

Ischemic complications after percutaneous transluminal coronary angioplasty

The ischemic complications ofpercutaneous transluminal coronary angioplasty (PTCA) include abrupt closure, which occurs in 2% to 10% of patients and is associated with increased morbidity and mortality. Periprocedural myocardial infarction due to side branch occlusion or embolization of platelet aggregates or thrombus occurs in 5% to 20% of patients. Patients with acute coronary syndromes, older age, and complex lesions are at greater risk of periprocedural complications. Technical advances, primarily stenting, are useful in the prevention and management of acute closure, but are also accompanied by thrombotic complications. It remains to be seen whether the new antithrombin agents reduce the rate of periprocedural complications if used in combination with aspirin and new antiplatelet therapies. These new antiplatelet agents (ticlopidine, clopidogrel, abciximab, eptifibatide, and tirofiban) reduce the rate of ischemic complications and have become standard adjunctive therapy for patients who undergo PTCA.

Frequency of major adverse cardiac events within one month of coronary angioplasty: a useful measure of operator performance

OBJECTIVES

To test one-month outcomes in a single center for their statistical power to corroborate conclusions derived from large multicenter databases.

BACKGROUND

Only with large, multicenter databases has it been possible to demonstrate more frequent occurrences of complications in patients treated by "low-volume operators." Critics feel that such analyses mask excellent performance by many "low-volume operators."

METHODS

In a high-volume cardiac catheterization laboratory in a large, nonuniversity teaching hospital, baseline clinical and angiographic characteristics were collected for a consecutive series of 1,029 patients treated by 37 percutaneous transluminal coronary intervention (PTCI) operators over a four-month period. One-month follow-up was obtained in 967 (94%) patients who form the basis for this analysis.

RESULTS

Only the group of operators performing <50 cases annually had a major adverse cardiac event (MACE) (death, myocardial infarction or symptom-driven revascularization) rate at one month significantly greater than predicted from baseline characteristics. (Observed rate: 15.1%, expected: 9.7%, 95% confidence interval [CI]: 4.7%, 14.6%.) The difference was driven by the significantly more frequent rate at which repeat revascularization was performed in patients treated by that group of operators (observed: 13.8%, expected: 7.1%, 95% CI: 2.8%, 11.4%).

CONCLUSIONS

As is true of analyses of large multicenter databases, lower volume operators as a group have less good outcomes than those performing more. The greater statistical power provided by one-month MACE rate offers advantages over the use of in-hospital complications for the analysis of operator performance.

Changing outcomes in percutaneous coronary interventions: a study of 34,752 procedures in northern New England, 1990 to 1997. Northern New England Cardiovascular Disease Study Group

OBJECTIVES

We sought to evaluate the changing outcomes of percutaneous coronary interventions (PCIs) in recent years.

BACKGROUND

The field of interventional cardiology has seen considerable growth in recent years, both in the number of patients undergoing procedures and in the development of new technology. In view of recent changes, we evaluated the experience of a large, regional registry of PCIs and outcomes over time.

METHODS

Data were collected from 1990 to 1997 on 34,752 consecutive PCIs performed at all hospitals in Maine (two), New Hampshire (two) and Vermont (one) supporting these procedures, and one hospital in Massachusetts. Univariate and multivariate regression analyses were used to control for case mix. Clinical success was defined as at least one lesion dilated to <50% residual stenosis and no adverse outcomes. In-hospital adverse outcomes included coronary artery bypass graft surgery (CABG), myocardial infarction and mortality.

RESULTS

Over time, the population undergoing PCIs tended to be older with increasing comorbidity. After adjustment for case mix, clinical success continued to improve from a low of 88.2% in earlier years to a peak of 91.9% in recent years (p trend <0.001). The rate of emergency CABG after PCI fell in recent years from a peak of 2.3% to 1.3% (p trend <0.001). Mortality rates decreased slightly from 1.2% to 1.1% (p trend 0.007).

CONCLUSIONS

There has been a significant improvement in clinical outcomes for patients undergoing PCIs in northern New England, including a significant decline in the need for emergency CABG.

Validation of risk adjustment models for in-hospital percutaneous transluminal coronary angioplasty mortality on an independent data set

OBJECTIVES

We sought to validate recently proposed risk adjustment models for in-hospital percutaneous transluminal coronary angioplasty (PTCA) mortality on an independent data set of high risk patients undergoing PTCA.

BACKGROUND

Risk adjustment models for PTCA mortality have recently been reported, but external validation on independent data sets and on high risk patient groups is lacking.

METHODS

Between July 1, 1994 and June 1, 1996, 1,476 consecutive procedures were performed on a high risk patient group characterized by a high incidence of cardiogenic shock (3.3%) and acute myocardial infarction (14.3%). Predictors of in-hospital mortality were identified using multivariate logistic regression analysis. Two external models of in-hospital mortality, one developed by the Northern New England Cardiovascular Disease Study Group (model NNE) and the other by the Cleveland Clinic (model CC), were compared using receiver operating characteristic (ROC) curve analysis.

RESULTS

In this patient group, an overall in-hospital mortality rate of 3.4% was observed. Multivariate regression analysis identified risk factors for death in the hospital that were similar to the risk factors identified by the two external models. When fitted to the data set, both external models had an area under the ROC curve >0.85, indicating overall excellent model discrimination, and both models were accurate in predicting mortality in different patient subgroups. There was a trend toward a greater ability to predict mortality for model NNE as compared with model CC, but the difference was not significant.

CONCLUSIONS

Predictive models for PTCA mortality yield comparable results when applied to patient groups other than the one on which the original model was developed. The accuracy of the two models tested in adjusting for the relatively high mortality rate observed in this patient group supports their application in quality assessment or quality improvement efforts.

Comparing physician-specific two-year patient outcomes after coronary angiography: methodologic issues and results

OBJECTIVES

We sought to evaluate methodologies to compare physician-related long-term patient outcomes appropriately.

BACKGROUND

Evaluation of physicians on the basis of short-term patient outcome is becoming widely practiced. These analyses fail to consider the importance of long-term outcome, and methods appropriate to such an analysis are poorly defined.

METHODS

All patients undergoing coronary angiography between 1992 and 1994 who received all of their cardiac care at our institution were followed for 27+/-13 months (mean+/-SD). Patients (n = 754) were cared for by one or more of 17 staff physicians. Risk-adjusted models were developed for four candidate clinical end points and cost. Physicians were then evaluated for each outcome measure.

RESULTS

Of the clinical end points, death could be modeled most accurately (c-statistic = 0.83). The c-statistics for other end points ranged from 0.63 to 0.70. Physicians with outcomes statistically different (p < 0.05) from other physicians were identified more commonly than would be expected from the play of chance (p = 0.005). However, improvement in the c-statistics by the addition of physician identifiers was very modest. Physician's evaluations by the four measures of clinical outcome were variably correlated (r = .00 to .85). Graphic display of clinical and cost results for each physician did identify certain physicians who might be judged to provide more cost-effective care than others.

CONCLUSIONS

Although comparisons of groups of physicians on the basis of long-term patient outcomes may have merit, individual physician-to-physician comparisons will be more difficult, owing to 1) multiple physicians contributing care to individual patients; 2) the poor predictive capacity of models other than that for survival; and 3) the modest apparent impact of differences in physician providers on long-term patient outcome. With these caveats in mind, modeling to compare patient outcomes of individual physicians with homogeneous patient populations or to identify gross outliers (good or bad) may be practicable in some patient-care systems, but may be inappropriate in others.

Relation between abrupt vessel closure and the anticoagulant response to heparin or bivalirudin during coronary angioplasty

The dosing of anticoagulants during coronary angioplasty is commonly guided by measurements of activated clotting time (ACT), but the usefulness of these measurements remains uncertain. The Hirulog Angioplasty Study was a randomized, double-blind comparison of heparin versus bivalirudin in 4,312 patients undergoing angioplasty for unstable or postinfarction angina. In 4,098 of the patients randomized, the balloon was inflated. All patients had ACT measurements 5 minutes after a weight-adjusted bolus of heparin or bivalirudin, and patients undergoing complicated or prolonged angioplasty procedures lasting >45 minutes had additional ACT measurements to guide further anticoagulant therapy. The analysis presented in this article evaluated the relation between the initial or maximum ACT measurements and the risk of abrupt vessel closure during heparin or bivalirudin therapy. Abrupt vessel closure occurred in 189 of 2,039 patients (9.3%) treated with heparin, and in 189 of 2,059 patients (9.2%) treated with bivalirudin (p = not significant). An inverse relation between the risk of abrupt closure and initial ACT measurements was observed in heparin-treated patients: the probability of abrupt vessel closure decreased by 1.3% for every 10-second increase in the initial ACT response to heparin therapy (p = 0.02). Among 903 of 2,039 heparin-treated patients (44%) who received additional heparin for prolonged or complicated procedures, the likelihood of abrupt vessel closure also decreased by 1.1% for every 10-second increase in ACT (p = 0.04). In 2,059 patients treated with bivalirudin, however, no relation between the probability of abrupt vessel closure and the initial ACT measurement was observed (p = 0.88). From the results it was concluded that when heparin is used during coronary angioplasty, the risk of abrupt vessel closure is related to patient responsiveness to anticoagulation therapy. Heparin-resistant patients are more likely to experience abrupt vessel closure than patients who have high ACT values in response to initial therapy. In contrast, when bivalirudin is used during coronary angioplasty, a flat relation between the risk of abrupt vessel closure and ACT values is seen. This suggests that the direct thrombin inhibitor, bivalirudin, provides more even levels of anticoagulation and more predictable levels of risk of abrupt closure than heparin. Measurements of ACT may not be necessary when bivalirudin is used during coronary angioplasty.

Operator volume and outcome of patients undergoing coronary stent placement

OBJECTIVES

The aim of this study was to assess the relation between operator experience in coronary stent placement procedures and the clinical outcome of patients.

BACKGROUND

The results of coronary balloon angioplasty are closely related to the experience of the operator performing the procedure. Data on the effect of operator experience on the results after coronary stent placement are missing.

METHODS

The study included 3,409 consecutive patients undergoing coronary stent placement for the management of coronary artery disease. A composite end point of cardiac death, myocardial infarction and aortocoronary bypass surgery during the first 30 days after the intervention, was the primary end point and the procedural failure was the secondary end point of the study.

RESULTS

Adverse clinical outcome occurred in 2.99% of the 3,409 patients undergoing coronary stent placement. Procedural failure was recorded in 2.08% of the patients. Operator volumes above 483 procedures were associated with a risk-adjusted adverse outcome rate of 1.70%+/-1.28%, which is significantly lower than the overall rate of 2.99%. Operator yearly volumes of under 90 procedures were associated with a risk-adjusted adverse outcome rate of 4.59%+/-1.17%, which is significantly higher than the overall rate of 2.99%. The operator experience was an independent predictor even after adjusting for the effect of other risk factors. The analysis demonstrated that an experience of at least 100 procedures is required to obtain better outcome even in patients with simple coronary lesions and that operators should perform at least 70 procedures annually to expect a better outcome in patients with both simple and complex coronary lesions.

CONCLUSIONS

Operator experience is a significant and independent predictor of the outcome of patients undergoing coronary stent placement. An experience of at least 100 procedures and an annual volume of at least 70 procedures are required to ensure a significantly better outcome after coronary stent implantation.

Identification of variables needed to risk adjust outcomes of coronary interventions: evidence-based guidelines for efficient data collection

OBJECTIVES

Our objectives were to identify and define a minimum set of variables for interventional cardiology that carried the most statistical weight for predicting adverse outcomes. Though "gaming" cannot be completely avoided, variables were to be as objective as possible and reproducible and had to be predictive of outcome in current databases.

BACKGROUND

Outcomes of percutaneous coronary interventions depend on patient risk characteristics and disease severity and acuity. Comparing results of interventions has been difficult because definitions of similar variables differ in databases, and variables are not uniformly tracked. Identifying the best predictor variables and standardizing their definitions are a first step in developing a universal stratification instrument.

METHODS

A list of empirically derived variables was first tested in eight cardiac databases (158,273 cases). Three end points (in-hospital death, in-hospital coronary artery bypass graft surgery, Q wave myocardial infarction) were chosen for analysis. Univariate and multivariate regression models were used to quantify the predictive value of the variable in each database. The variables were then defined by consensus by a panel of experts.

RESULTS

In all databases patient demographics were similar, but disease severity varied greatly. The most powerful predictors of adverse outcome were measures of hemodynamic instability, disease severity, demographics and comorbid conditions in both univariate and multivariate analyses.

CONCLUSIONS

Our analysis identified 29 variables that have the strongest statistical association with adverse outcomes after coronary interventions. These variables were also objectively defined. Incorporation of these variables into every cardiac dataset will provide uniform standards for data collected. Comparisons of outcomes among physicians, institutions and databases will therefore be more meaningful.

Value of the American College of Cardiology/American Heart Association stenosis morphology classification for coronary interventions in the late 1990s

The goal of this study was to reassess the accuracy of the American College of Cardiology/American Heart Association (ACC/AHA) stenosis morphology classification for predicting coronary intervention success and complications in the era of new devices. Previous studies performed in the early part of this decade for percutaneous transluminal coronary angioplasty in patients with multivessel coronary artery disease found that these criteria were predictive of success rates but not complication rates. Data for 957 consecutive coronary interventions in 1,404 lesions from June 1994 to October 1996 were prospectively classified according to ACC/AHA guidelines and entered into a database. Ninety-one and 9/10 of coronary interventions were successful, defined as <50% residual stenosis of each vessel attempted in the absence of major in-hospital complications, including Q-wave myocardial infarction, ventricular arrhythmia, need for emergency coronary artery bypass surgery, or death. Success rates did not differ between A (186 of 193, 96.3%), B1 (211 of 221, 95.5%), and B2 (676 of 711, 95.1%) lesions, but each was more successful than C (246 of 279, 88.2%) lesions (p <0.003, p < 0.004, and p = 0.0001, respectively). The class of lesion (A, B, or C) did not predict device (atherectomy, rotablator, and stent) use but specific morphologic characteristics of lesions within these classes were predictive of which device was used. Multiple regression analysis revealed that total occlusion and vessel tortuosity were predictive of procedure failure. Lesion type (A, B, or C) was not predictive of complications, but bifurcation lesions (p = 0.0045), presence of thrombus (p = 0.0001), inability to protect a major side branch (p = 0.0468), and degenerated vein graft lesions (p = 0.0283) were predictive. Thus, the ACC/AHA grading system is predictive of successful coronary intervention outcome, particularly of C-type characteristics, but not of complications or device success rate and selection. Although lesion type (A, B, or C) was not predictive of complications, specific lesion morphologies were predictive of adverse events and device use.

Operator volume and outcomes in 12,998 percutaneous coronary interventions. Northern New England Cardiovascular Disease Study Group

OBJECTIVES

We sought to determine whether there is a relation between operator volume and outcomes for percutaneous coronary interventions (PCIs).

BACKGROUND

A 1993 American College of Cardiology/American Heart Association task force stated that cardiologists should perform > or = 75 procedures/year to maintain competency in PCIs; however, there were limited data available to support this statement.

METHODS

Data were collected from 1990 through 1993 on 12,988 PCIs (12,118 consecutive hospital admissions) performed by 31 cardiologists at two hospitals in New Hampshire and two in Maine and one hospital in Massachusetts supporting these procedures. Operators were categorized into terciles based on annualized volume of procedures. Univariate and multivariate regression analyses were used to control for case-mix. Successful outcomes included angiographic success (all lesions attempted dilated to < 50% residual stenosis) and clinical success (at least one lesion dilated to < 50% residual stenosis and no adverse outcomes). In-hospital adverse outcomes included coronary artery bypass graft surgery (CABG), myocardial infarction (MI) and death.

RESULTS

After adjustment for case-mix, higher angiographic (low, middle and high terciles: 84.7%, 86.1% and 90.3%, p-trend 0.006) and clinical success rates (85.8%, 88.0% and 90.7%, p-trend 0.025), with fewer referrals to CABG (4.54%, 3.75% and 2.49%, p-trend <0.001), were seen as operator volume increased. There was a trend toward higher MI rates for high volume operators (2.00%, 1.98% and 2.57%, p-trend 0.06); all terciles had similar in-hospital mortality rates (1.09%, 0.96% and 1.05%, p-trend 0.8).

CONCLUSIONS

There is a significant relation between operator volume and outcomes in PCIs. Efforts should be directed toward understanding why high volume operators are more successful and encounter fewer adverse outcomes.

"Rescue" utilization of abciximab for the dissolution of coronary thrombus developing as a complication of coronary angioplasty

OBJECTIVES

This study sought to test the effect on thrombus score of the "rescue" utilization of the glycoprotein IIb/IIIa antagonist abciximab given to patients in whom intracoronary thrombus has developed as a complication after percutaneous transluminal coronary angioplasty (PTCA) and to determine its clinical utility.

BACKGROUND

Abciximab is effective in the prevention of acute ischemic complications when given prophylactically to patients during high risk PTCA. However, its ability to therapeutically dissolve newly formed intracoronary thrombus occurring as a complication after PTCA is not known.

METHODS

We performed an observational study in 29 consecutive patients who received abciximab (0.25 mg/kg body weight intravenous bolus, followed by a 12-h infusion at 10 microg/min) after attempted PTCA caused either the new development or further progression of thrombus. Angiograms were analyzed to determine thrombus score and Thrombolysis in Myocardial Infarction (TIMI) flow grade before and after abciximab. Procedural and clinical success and long-term outcome were also determined.

RESULTS

Thrombus score decreased from 3.0 +/- 0.9 (mean +/- SD) to 0.86 +/- 0.92 (p < 0.001), and TIMI flow grade increased from 2.5 +/- 0.7 to 2.9 +/- 0.3 (p = 0.008). No instances of distal embolization or no-reflow were noted. The procedural success (< or = 50% residual stenosis) rate was 97%. The clinical success (procedural success with no in-hospital myocardial infarction, bypass surgery or death) rate was 93%.

CONCLUSIONS

Dissolution of thrombus and restoration of TIMI grade 3 flow were readily achieved after administration of abciximab when delivered in a "rescue" manner after the development of thrombosis after PTCA. This novel use of abciximab will need to be validated in randomized trials.

Does low individual operator coronary interventional procedural volume correlate with worse institutional procedural outcome?

OBJECTIVES

To assess the relation between individual operator coronary interventional volume and incidence of complications, the in-hospital outcome at a single, moderate volume urban academic center was prospectively collected over a 3-year period.

BACKGROUND

A minimum of 75 coronary interventions/operator per year may be required in the future to obtain formal certification. However, few data exist regarding individual operator volumes and procedural outcome.

METHODS

Between January 1993 and December 1995, 1,389 consecutive procedures were performed or supervised by nine geographic full-time operators: 171 (12.3%) utilized various devices, and 350 (25.2%) involved multivessel coronary intervention. Left ventricular ejection fraction was 59 +/- 15% (mean +/- SD), and there were 1.7 +/- 0.7 vessels diseased (with > or = 70% stenosis). Clinical indications included stable angina in 22.5% of cases, unstable angina in 31.9%, acute myocardial infarction (MI) in 2.9%, post MI in 20.6%, shock or acute heart failure in 3.0% and restenosis in 19.1%. In the last consecutive 857 lesions in 655 cases, 20.7% type A, 55.5% type B and 23.8% type C lesions were categorized before coronary intervention.

RESULTS

Average yearly operator volume ranged from 26 to 83 cases (mean 51 +/- 26). Each operator has performed a total of 590 +/- 268 coronary interventions, with 10.0 +/- 4.3 years of coronary interventional experience. The mean angioplasty volume rating for the nine operators was 180 +/- 37 (> 170 considered adequate). The in-hospital major complication rate was 1.4% (95% confidence interval 0.7% to 1.893%) for all coronary interventions, including death in 3 patients, bypass surgery in 13, arrhythmia in 3 and Q wave MI in 2. To ascertain how these outcomes compared with standard measures of coronary interventional outcome, four previously published registries were reanalyzed in a similar manner. The rate of complications in the present study was found to be significantly lower than that of the 1992-1993 Society for Cardiac Angiography and Intervention registry (1.9%, n = 19,594, p < 0.05 [excludes ventricular arrhythmias]), the 1994 American College of Cardiology database (3.9%, n = 38,963, p = 0.001), the Mid-America Heart Institute outcome in 1988 (2.3%, n = 5,413, p = 0.02) and the 1985-1986 National Heart, Lung, and Blood Institute Registry (7.2%, n = 1,801, p = 0.001). Odds ratios and 95% confidence intervals showed the outcome in the current study to be at least comparable to the standard registries.

CONCLUSIONS

Despite individual operator volumes below those currently being considered for credentialing, the overall institutional outcome was excellent in a diverse and complex patient population.