Clinical Decision Support and Palivizumab: A Means to Protect from Respiratory Syncytial Virus.

BACKGROUND AND OBJECTIVES: Palivizumab can reduce hospitalizations due to respiratory syncytial virus (RSV), but many eligible infants fail to receive the full 5-dose series. The efficacy of clinical decision support (CDS) in fostering palivizumab receipt has not been studied. We sought a comprehensive solution for identifying eligible patients and addressing barriers to palivizumab administration. METHODS: We developed workflow and CDS tools targeting patient identification and palivizumab administration. We randomized 10 practices to receive palivizumab-focused CDS and 10 to receive comprehensive CDS for premature infants in a 3-year longitudinal cluster-randomized trial with 2 baseline and 1 intervention RSV seasons. RESULTS: There were 356 children eligible to receive palivizumab, with 194 in the palivizumab-focused group and 162 in the comprehensive CDS group. The proportion of doses administered to children in the palivizumab-focused intervention group increased from 68.4% and 65.5% in the two baseline seasons to 84.7% in the intervention season. In the comprehensive intervention group, proportions of doses administered declined during the baseline seasons (from 71.9% to 62.4%) with partial recovery to 67.9% during the intervention season. The palivizumab-focused group improved by 19.2 percentage points in the intervention season compared to the prior baseline season (p < 0.001), while the comprehensive intervention group only improved 5.5 percentage points (p = 0.288). The difference in change between study groups was significant (p = 0.05). CONCLUSIONS: Workflow and CDS tools integrated in an EHR may increase the administration of palivizumab. The support focused on palivizumab, rather than comprehensive intervention, was more effective at improving palivizumab administration.

Implications of increased left ventricular mass index on in-hospital outcomes in patients undergoing aortic valve surgery.

BACKGROUND: Increased left ventricular mass index has been shown to be associated with higher mortality in epidemiologic studies. However, the effect of increased left ventricular mass index on outcomes in patients undergoing aortic valve replacement is unknown. METHODS: We studied 473 consecutive patients undergoing elective aortic valve replacement to assess the influence of left ventricular mass index on outcomes in patients having this procedure. Echocardiographic left ventricular dimensions were used to calculate left ventricular mass index (considered increased if >134 g/m(2) in male patients and >110 g/m(2) in female patients). RESULTS: Left ventricular mass index was increased in 24% of patients undergoing aortic valve replacement. Postprocedural complications (respiratory failure, renal insufficiency, congestive heart failure, and atrial and ventricular arrhythmias), length of stay in the intensive care unit, and in-hospital mortality were increased in patients with increased left ventricular mass index. Multivariable analysis identified prior valve surgery (odds ratio, 4.3; 95% confidence interval, 1.2-15.7; P =.030), left ventricular ejection fraction (odds ratio, 1.07; 95% confidence interval, 1.01-1.14; P =.020), history of hypertension (odds ratio, 8.2; 95% confidence interval, 2.2-30.4; P =.002), history of liver disease (odds ratio, 50.4; 95% confidence interval, 4.2-609.0; P =.002), and increased left ventricular mass index (odds ratio, 38; 95% confidence interval, 9.3-154.1; P <.001) as independent predictors of in-hospital mortality. Furthermore, low output syndrome was identified as the most common mode of death (36%) after aortic valve replacement in patients with increased left ventricular mass index. CONCLUSIONS: Increased left ventricular mass index is associated with increased adverse in-hospital clinical outcomes in patients undergoing aortic valve replacement. Although this finding warrants special modification in perioperative management, further studies are needed to address whether outcomes in asymptomatic patients with aortic valve disease could be improved by earlier aortic valve replacement before a significant increase in left ventricular mass index.

Effect of postoperative atrial fibrillation on length of stay after cardiac surgery (The Postoperative Atrial Fibrillation in Cardiac Surgery study [PACS(2)].

Atrial fibrillation (AF) after cardiac surgery is thought to increase length of stay (LOS). A clinical pathway focused on the management of postoperative AF, including prophylaxis with beta blockers, was implemented to assess the effect of AF on LOS after cardiac surgery. Data were obtained on consecutive cardiac surgery patients in preoperative normal sinus rhythm, no prior history of AF, and no chronic antiarrhythmic therapy from January to May 1995 (control) and November 1996 to June 1997 (pathway). Statistical analysis was performed to assess the effect of postoperative AF on the LOS, clinical outcomes, and cost after cardiac surgery. Despite the clinical pathway, the LOS (7 days for both periods; p = 0.12) and incidence of AF (28.9% vs 28.4%; p = 0.92) remained unchanged. Unadjusted direct costs were 15% higher in the pathway period (p <0.001). Increased rates of beta-blocker therapy had a marginal effect on the incidence of postoperative AF, except in the group who only underwent primary coronary artery bypass graft surgery (31.2% vs 25.3%; p = 0.31). Multivariate analysis revealed that AF contributed only 1 to 1.5 days to the LOS. Thus, this investigation represents the most recent analysis of the effects of postoperative AF on LOS, clinical outcomes, and cost after cardiac surgery. Unlike prior studies, the impact of postoperative AF is less prominent in the current era of cardiac surgical care regardless of the presence of a clinical pathway addressing AF.

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.

Usefulness of hypotension during dobutamine echocardiography in predicting perioperative cardiac events.

This study was undertaken to determine the prognostic significance of hypotension induced during preoperative dobutamine stress echocardiography (DSE) before vascular and noncardiac thoracic surgery. Wall motion abnormality during DSE predicts perioperative risk. Although hypotension during DSE has not been shown to correlate with the presence or severity of coronary artery disease, its significance in perioperative risk assessment is unknown. We retrospectively studied 300 patients who had DSE within 6 months of noncardiac surgery. Perioperative events including death, myocardial infarction, ischemia, and arrhythmias were recorded. Odds ratios with 95% confidence intervals were used to examine the association between clinical and echocardiographic variables and perioperative events. A hypotensive response during DSE was seen in 85 patients (28%). Forty-eight patients (16%) had 54 perioperative complications including 4 cardiac-related deaths, 10 myocardial infarctions, 12 myocardial ischemic events, and 28 arrhythmias. Hypotension during DSE was predictive of the combined end point of perioperative cardiac mortality, myocardial infarction, and ischemia (odds ratio 4.04, 95% confidence interval 1.72 to 9.51). In a multivariate logistic regression model, hypotension during DSE remained a significant predictor (odds ratio 4.10, p<0.01). DSE-related hypotension was predictive of perioperative cardiac events and therefore may have a role in risk stratification before vascular or noncardiac thoracic surgery.

The International Registry of Acute Aortic Dissection (IRAD): new insights into an old disease.

CONTEXT: Acute aortic dissection is a life-threatening medical emergency associated with high rates of morbidity and mortality. Data are limited regarding the effect of recent imaging and therapeutic advances on patient care and outcomes in this setting. OBJECTIVE: To assess the presentation, management, and outcomes of acute aortic dissection. DESIGN: Case series with patients enrolled between January 1996 and December 1998. Data were collected at presentation and by physician review of hospital records. SETTING: The International Registry of Acute Aortic Dissection, consisting of 12 international referral centers. PARTICIPANTS: A total of 464 patients (mean age, 63 years; 65.3% male), 62.3% of whom had type A dissection. MAIN OUTCOME MEASURES: Presenting history, physical findings, management, and mortality, as assessed by history and physician review of hospital records. RESULTS: While sudden onset of severe sharp pain was the single most common presenting complaint, the clinical presentation was diverse. Classic physical findings such as aortic regurgitation and pulse deficit were noted in only 31.6% and 15.1% of patients, respectively, and initial chest radiograph and electrocardiogram were frequently not helpful (no abnormalities were noted in 12.4% and 31.3% of patients, respectively). Computed tomography was the initial imaging modality used in 61.1%. Overall in-hospital mortality was 27.4%. Mortality of patients with type A dissection managed surgically was 26%; among those not receiving surgery (typically because of advanced age and comorbidity), mortality was 58%. Mortality of patients with type B dissection treated medically was 10.7%. Surgery was performed in 20% of patients with type B dissection; mortality in this group was 31.4%. CONCLUSIONS: Acute aortic dissection presents with a wide range of manifestations, and classic findings are often absent. A high clinical index of suspicion is necessary. Despite recent advances, in-hospital mortality rates remain high. Our data support the need for continued improvement in prevention, diagnosis, and management of acute aortic dissection.

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.

Validation in a community hospital setting of a clinical rule to predict preserved left ventricular ejection fraction in patients after myocardial infarction.

BACKGROUND: A previous study showed that patients with previous myocardial infarction (MI) who meet 4 simple clinical and/or electrocardiographic criteria have a left ventricular ejection fraction (LVEF) of 40% or greater, with a positive predictive value of 98%. The objective of this study was to validate this clinical rule in the community hospital setting. METHODS: Retrospective chart review in a 330-bed community hospital. Two hundred thirteen consecutive patients with MI were identified between June 1, 1993, and March 31, 1995. Left ventricular ejection fraction was predicted in a blinded fashion by means of the clinical rule before the actual LVEF test was reviewed. RESULTS: We identified 213 patients admitted with the primary discharge diagnosis of acute MI. All patients met standard clinical and enzymatic definitions for acute MI and had at least 1 measure of LVEF, such as echocardiography, ventricular angiography, or gated blood pool scan. The clinical rule predicted that 83 patients (39.0%) would have an LVEF of 40% or greater. Of these 83 patients, 71 had an ejection fraction of 40% or greater, for a positive predictive value of 86%. Of the 12 patients who were incorrectly predicted to have a preserved LVEF, 6 (50%) had an index non-Q-wave anterior MI (P<.001). Reanalyzing the patient population with a fifth variable (anterior non-Q-wave MI) added to the original 4 variables increased the positive predictive value to 91%. CONCLUSION: This simple clinical prediction rule has a positive predictive value of 86% when applied in the community hospital setting. Patients with anterior non-Q-wave MI may be 1 group in whom the rule is inaccurate, and expanding the clinical rule to 5 variables may increase the positive predictive value. When a technology-based assessment of left ventricular function is considered in patients after an MI, this prediction rule may allow for a more cost-effective patient selection, and as many as 40% of patients who have had acute MIs may require no testing at all.

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.

Surgical delay for acute type A dissection with malperfusion.

BACKGROUND: An acute type A aortic dissection is considered a surgical emergency. Review of the risk factors for a type A dissection showed that preoperative malperfusion was associated with a 22% (2/9) intraoperative mortality and an 89% (8/9) hospital mortality. Intraoperative deaths were secondary to pulmonary failure resulting from capillary leak; the remaining patients died of multiorgan failure resulting from reperfusion injury. METHODS: The surgical delay approach was adopted for malperfused patients, and treatment in these patients included percutaneous reperfusion, with aortic fenestration and branch stenting where appropriate. Twenty patients had a type A dissection and malperfusion shown by pulsed-wave Doppler echocardiography, transesophageal echocardiography, or spiral computed tomographic scanning. Malperfusion was documented by angiography. After reperfusion, all patients' conditions were stabilized in the intensive care unit; intravenous beta-blockers were administered to decrease the maximum rate of increase of left ventricular pressure. Once patients completely recovered from the consequences of malperfusion, surgical repair was performed. Statistical comparison of the non-delay and delay groups was performed using Fisher's exact test and Student's t test. Multiple logistic regression analysis was used to establish independent predictors for mortality. RESULTS: The mean delay to repair was 20 days (2 to 67 days). Four (31%) patients were discharged home and readmitted for operation. Three patients (15%) died preoperatively, 1 of retrograde dissection and rupture and 2 of reperfusion injury. Seventeen underwent surgical repair, with two deaths (12%); 15 (75%) were discharged, with an average follow-up of 16.8 months (p < 0.003). Delay was the only independent predictor of outcome. CONCLUSIONS: Patients with an acute type A dissection and malperfusion should undergo percutaneous reperfusion, and surgical repair should be delayed until the reperfusion injury resolves.