Impact of health care initiatives on outcomes of acute coronary syndromes.

Assessing efforts to apply clinical guidelines in community practice, with the goal of improving the quality and outcomes of care, presents many challenges.

Predictors of major bleeding in acute coronary syndromes: the Global Registry of Acute Coronary Events (GRACE).

AIMS: There have been no large observational studies attempting to identify predictors of major bleeding in patients with acute coronary syndromes (ACS), particularly from a multinational perspective. The objective of our study was thus to develop a prediction rule for the identification of patients with ACS at higher risk of major bleeding. METHODS AND RESULTS: Data from 24045 patients from the Global Registry of Acute Coronary Events (GRACE) were analysed. Factors associated with major bleeding were identified using logistic regression analysis. Predictive models were developed for the overall patient population and for subgroups of patients with ST-segment elevation myocardial infarction (STEMI), non-ST-segment elevation myocardial infarction (NSTEMI) and unstable angina. The overall incidence of major bleeding was 3.9% (4.8% in patients with STEMI, 4.7% in patients with NSTEMI and 2.3% in patients with unstable angina). Advanced age, female sex, history of bleeding, and renal insufficiency were independently associated with a higher risk of bleeding (P<0.01). The association remained after adjustment for hospital therapies and performance of invasive procedures. After adjustment for a variety of potential confounders, major bleeding was significantly associated with an increased risk of hospital death (adjusted odds ratio 1.64, 95% confidence interval 1.18, 2.28). CONCLUSIONS: In routine clinical practice, major bleeding is a relatively frequent non-cardiac complication of contemporary therapy for ACS and it is associated with a poor hospital prognosis. Simple baseline demographic and clinical characteristics identify patients at increased risk of major bleeding.

Early revascularization is associated with improved survival in elderly patients with acute myocardial infarction complicated by cardiogenic shock: a report from the SHOCK Trial Registry.

AIMS: The SHould we emergently revascularize Occluded Coronaries in cardiogenic shocK (SHOCK) Trial showed no benefit of early revascularization in patients aged >/=75 years with acute myocardial infarction and cardiogenic shock. We examined the effect of age on treatment and outcomes of patients with cardiogenic shock in the SHOCK Trial Registry. METHODS AND RESULTS: We compared clinical and treatment factors in patients in the SHOCK Trial Registry with shock due to pump failure aged <75 years (n=588) and >/=75 years (n=277), and 30-day mortality of patients treated with early revascularization <18 hours since onset of shock and those undergoing a later or no revascularization procedure. After excluding early deaths covariate-adjusted relative risk and 95% confidence intervals were calculated to compare the revascularization strategies within the two age groups. Older patients more often had prior myocardial infarction, congestive heart failure, renal insufficiency, other comorbidities, and severe coronary anatomy. In-hospital mortality in the early vs. late or no revascularization groups was 45 vs. 61% for patients aged <75 years (p=0.002) and 48 vs. 81% for those aged >/=75 years (p=0.0003). After exclusion of 65 early deaths and covariate adjustment, the relative risk was 0.76 (0.59, 0.99; p=0.045) in patients aged <75 years and 0.46 (0.28, 0.75; p=0.002) in patients aged >/=75 years. CONCLUSIONS: Elderly patients with myocardial infarction complicated by cardiogenic shock are less likely to be treated with invasive therapies than younger patients with shock. Covariate-adjusted modeling reveals that elderly patients selected for early revascularization have a lower mortality rate than those receiving a revascularization procedure later or never.

Predictors of length of stay after coronary stenting.

BACKGROUND: Postprocedure length of stay (LOS) remains an important determinant of medical costs after coronary stenting. Variables that predict LOS in this setting have not been well characterized. METHODS: We evaluated 359 consecutive patients who underwent coronary stenting with antiplatelet therapy. Sequential multiple linear regression (MLR) models were constructed with use of 4 types of variables to predict log-transformed LOS: preprocedure, intraprocedure, and postprocedure factors and adverse outcomes. RESULTS: Preprocedure factors alone explained more than one third of the variability in postprocedure LOS (adjusted R(2) = 0.37). The addition of procedural variables added little to the model (adjusted R(2) = 0.39). Entering nonoutcome postprocedure variables significantly enhanced the predictive capacity of the model, explaining more than half the variability in postprocedure LOS (adjusted R(2) = 0.54). In the final model, addition of outcome variables increased its predictive capacity only slightly (adjusted R(2) = 0.61). In this model, significant preprocedure factors included: myocardial infarction (MI) within 24 hours, MI within 1 to 30 days, women with peripheral vascular disease, intravenous heparin, and chronic atrial fibrillation. High-risk intervention was the only significant intraprocedure variable. Significant postprocedure factors included periprocedure ischemia; cerebrovascular accident or transient ischemic attack; treatment with intravenous heparin or nitroglycerin or intra-aortic balloon pump; and need for blood transfusion. Significant adverse outcomes included contrast nephropathy, gastrointestinal bleeding, arrhythmia, vascular complication, and repeat angiography. CONCLUSION: This prediction model identifies a number of potentially reversible factors responsible for prolonging LOS and may enable the development of more accurate risk-adjusted methods with which to improve or compare care.

Simple bedside additive tool for prediction of in-hospital mortality after percutaneous coronary interventions.

BACKGROUND: Risk-adjustment models for percutaneous coronary intervention (PCI) mortality have been recently reported, but application in bedside prediction of prognosis for individual patients remains untested. METHODS AND RESULTS: Between July 1, 1997 and September 30, 1999, 10 796 consecutive procedures were performed in a consortium of 8 hospitals. Predictors of in-hospital mortality were identified by use of multivariate logistic regression analysis. The final model was validated by use of the bootstrap technique. Additional validation was performed on an independent data set of 5863 consecutive procedures performed between October 1, 1999, and August 30, 2000. An additive risk-prediction score was developed by rounding coefficients of the logistic regression model to the closest half-integer, and a visual bedside tool for the prediction of individual patient prognosis was developed. In this patient population, the in-hospital mortality rate was 1.6%. Multivariate regression analysis identified acute myocardial infarction, cardiogenic shock, history of cardiac arrest, renal insufficiency, low ejection fraction, peripheral vascular disease, lesion characteristics, female sex, and advanced age as independent predictors of death. The model had excellent discrimination (area under the receiver operating characteristic curve, 0.90) and was accurate for prediction of mortality among different subgroups. Near-perfect correlation existed between calculated scores and observed mortality, with higher scores associated with higher mortality. CONCLUSIONS: Accurate predictions of individual patient risk of mortality associated with PCI can be achieved with a simple bedside tool. These predictions could be used during discussions of prognosis before and after PCI.

Balloon atrial septostomy in end-stage pulmonary hypertension guided by a novel intracardiac echocardiographic transducer.

Blade and balloon atrial septostomy has been used to reduce cardiopulmonary symptoms and as a bridge to lung or heart lung transplant in primary pulmonary hypertension. Due to severe right atrial dilatation and resultant loss of anatomical landmarks, the procedure is technically difficult, and the reported postprocedure mortality rate varies between 5% and 50%. Among others, marked systemic desaturation and systemic hypotension presumably secondary to an excessively large atrial septal defect have been reported as causes of postprocedure death. We report a case where a novel intracardiac catheter-based phased-array 5.5--10 MHz transducer with spectral and color-flow Doppler capabilities was used to assist a balloon atrial septostomy and to obtain hemodynamic data in a patient with end-stage pulmonary hypertension.

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.

Prevalence and significance of exit block during arrhythmias arising in pulmonary veins.

INTRODUCTION: Recent studies described the occurrence of conduction block within pulmonary veins. The purpose of this study was to evaluate the prevalence of exit block during arrhythmias that arise in pulmonary veins. METHODS AND RESULTS: Twenty-five patients with atrial tachycardia/fibrillation underwent successful ablation of 28 arrhythmogenic foci within a pulmonary vein. The prevalence of exit block in the pulmonary veins was determined in 28 arrhythmogenic pulmonary veins and 40 nonarrhythmogenic pulmonary veins. During isolated premature depolarizations, exit block in a pulmonary vein was observed at 50% of arrhythmogenic pulmonary vein sites and was never observed within pulmonary veins that did not generate a tachycardia (P < 0.01). During tachycardia, exit block from a pulmonary vein was observed in 61% of the arrhythmogenic pulmonary veins. The mean cycle length of the pulmonary vein tachycardias associated with exit block was significantly shorter than the cycle length of tachycardias that were not associated with exit block (163 +/- 32 vs 251 +/- 45 msec, P < 0.001). Exit block in two pulmonary veins during the same episode of tachycardia was observed in 3 of the 28 arrhythmogenic pulmonary veins (11%) in three different patients. Simultaneous recordings in the two pulmonary veins demonstrated bursts of tachycardia in both veins that were not synchronized. Radiofrequency catheter ablation of the arrhythmogenic site in one of the pulmonary veins eliminated spontaneous recurrences of tachycardia from the other pulmonary vein. CONCLUSION: Exit block from pulmonary veins is a common observation during tachycardias generated within pulmonary veins and indicates that an arrhythmogenic pulmonary vein has been identified. The occurrence of exit block in more than one pulmonary vein most likely is attributable to simultaneous tachycardias, one or both of which may be tachycardia induced and perpetuated by the other.

IL-8 is an angiogenic factor in human coronary atherectomy tissue.

BACKGROUND: Interleukin-8 (IL-8), a CXC chemokine that induces the migration and proliferation of endothelial cells and smooth muscle cells, is a potent angiogenic factor that may play a role in atherosclerosis. Previously, IL-8 has been reported in atherosclerotic lesions and circulating macrophages from patients with atherosclerosis. Therefore, we sought to determine whether IL-8 plays a role in mediating angiogenic activity in atherosclerosis. METHODS AND RESULTS: Homogenates from 16 patients undergoing directional coronary atherectomy (DCA) and control samples from the internal mammary artery (IMA) of 7 patients undergoing bypass graft surgery were assessed for IL-8 content by specific ELISA, immunohistochemistry, and in situ hybridization for IL-8 mRNA. The contribution of IL-8 to net angiogenic activity was assessed using the rat cornea micropocket assay and cultured cells. IL-8 expression was significantly elevated in DCA samples compared with IMA samples (1.71+/-0.6 versus 0.05+/-0.03 ng/mg of total protein; P<0.01). Positive immunolocalization of IL-8 was found exclusively in DCA tissue sections, and it correlated with the presence of factor VIII-related antigen. In situ reverse transcriptase polymerase chain reaction revealed the expression of IL-8 mRNA in DCA tissue. Corneal neovascular response, defined by ingrowth of capillary sprouts toward the implant, was markedly positive with DCA pellets, but no constitutive vessel ingrowth was seen with IMA specimens. Neutralizing IL-8 attenuated both the in vivo corneal neovascular response and the in vitro proliferation of cultured cells. CONCLUSIONS: The results suggest that, in human coronary atherosclerosis, IL-8 is an important mediator of angiogenesis and may contribute to plaque formation via its angiogenic properties.

Comparison of endocardial activation times at effective and ineffective ablation sites within the pulmonary veins.

INTRODUCTION: Recent studies demonstrated that atrial arrhythmias may be generated within pulmonary veins. The purpose of this study was to compare the endocardial activation times at effective and ineffective ablation sites during radiofrequency catheter ablation of arrhythmias initiated or generated within pulmonary veins. METHODS AND RESULTS: Twenty-one of 28 patients without structural heart disease underwent successful ablation of 23 arrhythmogenic foci within a pulmonary vein. Electrograms were recorded at 75 pulmonary venous sites and categorized into three groups: 23 successful ablation sites; 28 unsuccessful target sites within an arrhythmogenic pulmonary vein; and 24 sites within nonarrhythmogenic pulmonary veins. The endocardial activation time of premature depolarizations arising at successful target sites was significantly earlier than at other sites. During premature depolarizations, an endocardial activation time of -75 msec or earlier had a sensitivity of 83% and a specificity of 79% for identification of a successful ablation site. Endocardial activation times earlier than -100 msec were recorded only at successful ablation sites, and endocardial activation times later than -30 msec were recorded only at sites within nonarrhythmogenic pulmonary veins. The presence of a split potential during sinus rhythm or premature depolarizations was not a specific indicator of a successful ablation site. CONCLUSION: The endocardial activation times of premature depolarizations that arise within pulmonary veins and initiate atrial tachycardia/fibrillation are useful in identifying successful ablation sites.

Left ventricular apical puncture: a procedure surviving well into the new millennium.

We report two patients with a history of prior mitral valve and aortic valve replacement with St. Jude prosthetic valves, who were referred for repeat valve replacement after noninvasive assessment was suggestive of prosthetic valve malfunction. Both patients were managed medically after evaluation with direct left ventricular apical puncture revealed normal hemodynamics in the first and mild aortic stenosis in the second patient. These two cases illustrate that, despite the advancements in the noninvasive evaluation of prosthetic heart valves, left ventricular direct puncture continues to have an important value in the evaluation of patients referred for repeat valve replacement, and it can prevent unnecessary surgeries associated with a high risk of morbidity and mortality. Cathet. Cardiovasc. Intervent. 49:68-73, 2000.

Guiding catheter thrombectomy during percutaneous coronary interventions for acute coronary syndromes.

Despite the advancements in the pharmacological and mechanical treatment of acute coronary syndromes, intracoronary thrombus and distal embolization remain among the major limitations of percutaneous transluminal coronary interventions. We describe three cases in which intragraft or intracoronary thrombus was completely aspirated during PTCI using the guiding catheter. In the first case, a 4-cm-long unfragmented embolized thrombus was effectively and completely aspirated from a saphenous vein graft, with immediate restoration of normal flow. In the second case, multiple fragments of embolized thrombus were aspirated from a large right coronary artery, while in the third case, intragraft thrombus was electively aspirated. In each case, the index lesions were then successfully stented without complications. Cathet. Cardiovasc. Intervent. 49:192-196, 2000.

Extracorporeal life support to left ventricular assist device bridge to heart transplant: A strategy to optimize survival and resource utilization.

BACKGROUND: The use of extracorporeal life support (extracorporeal membrane oxygenation [ECMO]) as a direct bridge to heart transplant in adult patients is associated with poor survival. Similarly, the use of an implantable left ventricular assist device (LVAD) to salvage patients with cardiac arrest, severe hemodynamic instability, and multiorgan failure results in poor outcome. The use of LVAD implant in patients who present with cardiogenic shock who have not been evaluated for transplantation or who have sustained a recent myocardial infarction also raises concerns. ECMO may provide reasonable short-term support to patients with severe hemodynamic instability, permit recovery of multiorgan injury, and allow time to complete a transplant evaluation before long-term circulatory support with an implantable LVAD is instituted. After acquisition of the HeartMate LVAD (Thermo Cardiosystems, Inc), we began using ECMO as a bridge to an implantable LVAD and, subsequently, to transplantation in selected high-risk patients. METHODS AND RESULTS: From October 1, 1996, through September 30, 1998, 32 adult patients who presented with refractory cardiogenic shock (cardiac index <2.0 L. min(-1). m(-2), with systolic blood pressure <100 mm Hg and pulmonary capillary wedge pressure >/=24 mm Hg and dependent on >/=2 inotropes with or without intra-aortic balloon pump) were evaluated and accepted as candidates for mechanical assistance as a bridge to transplant. Of the 32 patients, 14 (group I) had a cardiac arrest or severe hemodynamic instability (systolic blood pressure 3 mg/dL or oliguria; international normalized ratio >1.5 or transaminases >5 times normal or total bilirubin >3 mg/dL; and needing mechanical ventilation). Group I patients were placed on ECMO support; 7 underwent subsequent LVAD implant and 1 was bridged directly to transplant. Six patients in group I survived to transplant hospitalization discharge. The remaining 18 patients (group II) underwent LVAD implant without ECMO support; 12 survived to transplant hospitalization discharge and 2 remained alive with ongoing LVAD support and awaited transplant. One-year actuarial survival from the initiation of circulatory support was 43% in group I and 75% in group II. One-year actuarial survival from the time of LVAD implant in group I, conditional on surviving ECMO, was 71% (P=NS compared with group II). CONCLUSIONS: In appropriately selected high-risk patients, the rate of LVAD survival after initial ECMO support was not significantly different from the survival rate after LVAD support alone. An initial period of resuscitation with ECMO is an effective strategy to salvage patients with extreme hemodynamic instability and multiorgan injury. Use of LVAD resources is improved by avoiding LVAD implant in a very-high-risk cohort of patients who do not survive ECMO.

Emergency extracorporeal membrane oxygenation (ECMO)-supported percutaneous coronary interventions in the fibrillating heart.

We describe two cases of refractory ventricular fibrillation complicating transcatheter interventional procedures. Extracorporeal membrane oxygenation was used in each to support percutaneous coronary revascularization in the fibrillating heart as a means of facilitating successful restoration of sinus rhythm. Cathet. Cardiovasc. Intervent. 48:402-405, 1999.

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.

Evaluating and improving the delivery of heart care: the University of Michigan experience.

With increasing pressure to curb escalating costs in medical care, there is particular emphasis on the delivery of cardiovascular services, which account for a substantial portion of the current healthcare dollar spent in the United States. A variety of tools were used to improve performance at the University of Michigan Health System, one of the oldest university-affiliated hospitals in the United States. The tools included initiatives to understand outcomes after coronary bypass operations and coronary angioplasty through use of proper risk-adjusted models. Critical pathways and guidelines were implemented to streamline care and improve quality in interventional cardiology, management of myocardial infarction, and preoperative assessment of patients undergoing vascular operations. Strategies to curb unnecessary costs included competitive bidding of vendors for expensive cardiac commodities, pharmacy cost reductions, and changes in nursing staff. Methods were instituted to improve guest services and partnerships with the community in disease prevention and health promotion.

Superimposed stents in the management of acute recoil after Palmaz-Schatz stenting.

We report a patient in whom aorto-ostial stenting with a Palmaz-Schatz coronary stent was complicated by significant acute elastic recoil, despite appropriate positioning of the stent and full expansion of a high-pressure, postdilatation balloon. Superimposing a Palmaz biliary stent overcame the inward radial force of this lesion and achieved an adequate lumen.

Frequency, predictors, and appropriateness of blood transfusion after percutaneous coronary interventions.

Increased awareness of the risks of blood-borne infections has recently led to profound changes in the practice of transfusion medicine. These changes include, among others, the development of guidelines by the American College of Physicians (ACP) for transfusion. Although the incidence and predictors of vascular complications of percutaneous interventions have been well defined, there are currently no data on frequency, risk factors, and appropriateness of blood transfusions. We performed a retrospective analysis of 628 consecutive percutaneous coronary revascularization procedures. Predictors of blood transfusion were identified using multivariate logistic regression analysis. Appropriateness of transfusions was determined using modified ACP guidelines. Transfusions were administered after 8.9% of interventions (56 of 628). Multivariate analysis identified age >70 years, female gender, procedure duration, coronary stenting, acute myocardial infarction, postprocedural use of heparin and intra-aortic balloon pump placement as independent predictors of blood transfusions (all p <0.05). According to the ACP guidelines, 36 of 56 patients (64%) received transfusions inappropriately. Transfusion reactions (fever) occurred in 10% of patients who received tranfusions appropriately and in 5% of patients who received tranfusions inappropriately. The estimated additional costs per procedure related to transfusions were $551 and $419, respectively. In conclusion, unnecessary transfusions were performed frequently after percutaneous coronary interventions. Application of available guidelines could reduce the number of unnecessary transfusions, thus avoiding exposure of patients to additional risks and reducing procedural costs.