Innovation and comparative-effectiveness research in cardiac surgery

Validation of EuroSCORE II to predict mortality in post-cardiac surgery patients in East Java tertiary hospital

BACKGROUND The European system for cardiac operative risk evaluation (EuroSCORE) II is one of the established risk models used to predict mortality after cardiac surgery. However, its application as a mortality predictor for Indonesian adult cardiac surgery is still unknown. This study aimed to examine the validation of EuroSCORE II in predicting the mortality following adult cardiac surgery in Indonesian adults. METHODS This retrospective cohort study collected data from the medical records and the database of the Department of Thoracic Cardiac and Vascular Surgery at Soetomo General Hospital, Surabaya. Data on the EuroSCORE II variables were collected for patients aged >18 years who underwent coronary artery bypass, heart valve, heart tumors, aortic surgeries, or a combination of these surgeries between January 2016 and December 2018. In-hospital mortality prediction was calculated using the online calculator at www.euroscore.org. The calibration of the EuroSCORE II model was conducted using the Hosmer–Lemeshow test, and discrimination analysis was done using receiver operating characteristic (ROC) curves with area under the ROC curve (AUC) calculation. RESULTS A total of 213 patients met the inclusion criteria and were analyzed for this study. Mortality was 8.9%. The predicted and actual mortalities were 1.74% and 8.9%, respectively. The significance (p-value) of the Hosmer–Lemeshow test was 0.55, indicating good calibration. The AUC of ROC curve was 0.85 (95% CI = 0.77–0.92, p<0.001), suggesting good discrimination. CONCLUSIONS EuroSCORE II has a good calibration and discrimination for cardiac surgery in Indonesian adults.

Preoperative pulmonary function in all comers for cardiac surgery predicts mortality†

OBJECTIVES

Although reduced lung function and chronic obstructive pulmonary disease (COPD) is associated with higher risk of death following cardiac surgery, preoperative spirometry is not performed routinely. The aim of this study was to investigate the relationship between preoperative lung function and postoperative complications in all comers for cardiac surgery irrespective of smoking or COPD history.

METHODS

Preoperative spirometry was performed in elective adult cardiac surgery patients. Airflow obstruction was defined as the ratio of forced expiratory volume in 1 s (FEV1)/forced vital capacity ratio below the lower limit of normal (LLN) and reduced forced ventilatory capacity defined as FEV1 <LLN.

RESULTS

A history of COPD was reported by 132 (19%) patients; however, only 74 (56%) had spirometry-verified airflow obstruction. Conversely, 64 (12%) of the 551 patients not reporting a history of COPD had spirometry-verified airflow obstruction. The probability of death was significantly higher in patients with airflow obstruction (8.8% vs 4.5%, P = 0.04) and in patients with a FEV1 <LLN (8.7% vs 3.7%, P = 0.007). In the multivariate analysis were age [hazard ratio (HR) 1.6, 95% confidence interval (CI) 1.0-2.5; P = 0.04], prolonged cardiopulmonary bypass time (HR 1.2, 95% CI 1.02-1.3; P = 0.03), reduced kidney function (HR 2.5, 95% CI 1.2-5.6; P = 0.02) and FEV1 <LLN (HR 2.4, 95% CI 1.1-5.2; P = 0.03) all independently associated with an increased risk of death.

CONCLUSIONS

Preoperative spirometry reclassified 18% of the patients. A reduced FEV1 independently doubled the risk of death. Inclusion of preoperative spirometry in routine screening of cardiac surgical patients may improve risk prediction and identify high-risk patients.

CLINICAL TRIAL REGISTRATION NUMBER

NCT01614951 (ClinicalTrials.gov).

Choice of vein-harvest technique for coronary artery bypass grafting: rationale and design of the REGROUP trial

The Randomized Endo-vein Graft Prospective (REGROUP) trial (ClinicalTrials.gov NCT01850082) is a randomized, intent-to-treat, 2-arm, parallel-design, multicenter study funded by the Cooperative Studies Program (CSP No. 588) of the US Department of Veterans Affairs. Cardiac surgeons at 16 Veterans Affairs (VA) medical centers with technical expertise in performing both endoscopic vein harvesting (EVH) and open vein harvesting (OVH) were recruited as the REGROUP surgeon participants. Subjects requiring elective or urgent coronary artery bypass grafting using cardiopulmonary bypass with use of ≥1 saphenous vein graft will be screened for enrollment using pre-established inclusion/exclusion criteria. Enrolled subjects (planned N = 1150) will be randomized to 1 of the 2 arms (EVH or OVH) after an experienced vein harvester has been assigned. The primary outcomes measure is the rate of major adverse cardiac events (MACE), including death, myocardial infarction, or revascularization. Subject assessments will be performed at multiple times, including at baseline, intraoperatively, postoperatively, and at discharge (or 30 days after surgery, if still hospitalized). Assessment of leg-wound complications will be completed at 6 weeks after surgery. Telephone follow-ups will occur at 3-month intervals after surgery until the participating sites are decommissioned after the trial's completion (approximately 4.5 years after the full study startup). To assess long-term outcomes, centralized follow-up of MACE for 2 additional years will be centrally performed using VA and non-VA clinical and administrative databases. The primary MACE outcome will be compared between the 2 arms, EVH and OVH, at the end of the trial duration.

Forced expiratory volume in one second predicts length of stay and in-hospital mortality in patients undergoing cardiac surgery: a retrospective cohort study

Objective

An aging population and increasing use of percutaneous therapies have resulted in older patients with more co-morbidity being referred for cardiac surgery. Objective measurements of physiological reserve and severity of co-morbid disease are required to improve risk stratification. We hypothesised that FEV₁ would predict mortality and length of stay following cardiac surgery.

Methods

We assessed clinical outcomes in 2,241 consecutive patients undergoing coronary artery bypass grafting and/or valve surgery from 2001 to 2007 in a regional cardiac centre. Generalized linear models of the association between FEV₁ and length of hospital stay and mortality were adjusted for age, sex, height, body mass index, socioeconomic status, smoking, cardiovascular risk factors, long-term use of bronchodilators or steroids for lung disease, and type and urgency of surgery. FEV₁ was compared to an established risk prediction model, the EuroSCORE.

Results

Spirometry was performed in 2,082 patients (93%) whose mean (SD) age was 67 (10) years. Median hospital stay was 3 days longer in patients in the lowest compared to the highest quintile for FEV₁, 1.35-fold higher (95% CI 1.20–1.52; p<0.001). The adjusted odds ratio for mortality was increased 2.11-fold (95% CI 1.45–3.08; p<0.001) per standard deviation decrement in FEV₁ (800 ml). FEV₁ improved discrimination of the EuroSCORE for mortality. Similar associations were found after excluding people with known pulmonary disease and/or airflow limitation on spirometry.

Conclusions

Reduced FEV₁ strongly predicted increased length of stay and in-hospital mortality following cardiac surgery. FEV₁ is a widely available measure of physiological health that may improve risk stratification of complex patients undergoing cardiac surgery and should be evaluated for inclusion in new prediction tools.

Surgeon volume is associated with cost and variation in surgical treatment of proximal humeral fractures

BACKGROUND

The issue of rising costs will likely dominate the healthcare debate in the forthcoming years.

QUESTIONS/PURPOSES

We assessed factors including surgeon volume that were associated with lower hospital costs and variations in surgical treatment for proximal humeral fractures.

METHODS

We used national databases for 2001 to 2008 to extract information on 25,731 patients undergoing surgery for proximal humeral fractures. We calculated hospital cost by converting hospital charges based on the hospital accounting reports collected by the Centers for Medicare & Medicaid Services.

RESULTS

In a multivariate linear regression analysis, higher surgeon volume, open reduction and internal fixation (versus hemiarthroplasty), and lower burden of comorbidities were associated with lower hospital cost. Higher surgeon volume was linearly associated with lower hospital costs such that, on average, adjusting for all other factors, a surgeon performing 20 shoulder arthroplasties per year saves a hospital approximately US $1800 per surgery. Factors associated with higher utilization of hemiarthroplasty included high surgeon volume (odds ratio [OR] = 1.46; 95% CI = 1.43, 1.97; as compared with low surgeon volume) and earlier years of our study period (OR = 0.61; 95% CI = 0.56, 0.66; for hemiarthroplasty in 2007-2008 versus 2001-2002).

CONCLUSIONS

Higher surgeon volume was associated with lower hospital costs for proximal humeral fractures. Therefore, policies on minimum volume requirements by hospitals may result in substantial cost savings. There is provider-based practice variation in the surgical treatment of proximal humeral fractures and evidence-based guidelines in this area are needed.

LEVEL OF EVIDENCE

Level III, economic analysis. See Instructions for Authors for a complete description of levels of evidence.

On-pump versus off-pump coronary artery bypass surgery in elderly patients: results from the Danish on-pump versus off-pump randomization study

BACKGROUND

Conventional coronary artery bypass grafting performed with the use of cardiopulmonary bypass is a well-validated treatment for patients with ischemic heart disease. Off-pump coronary artery bypass grafting (OPCAB) has been suggested to reduce the number of perioperative complications, especially in elderly patients.

METHODS AND RESULTS

In a multicenter, randomized trial, we assigned 900 patients >70 years of age to conventional coronary artery bypass grafting or OPCAB surgery. After 30 days, a blinded end-point committee assessed whether a combined end point of death, stroke, or myocardial infarction had occurred. At baseline and 6 months postoperatively, self-assessed quality of life was measured with the Medical Outcomes Study Short Form-36 and EuroQol-5D questionnaires. A 6-month follow-up of mortality was performed through the Danish National Registry. The proportion of patients experiencing the combined end point within 30 days was 10.2% for conventional coronary artery bypass grafting and 10.7% for OPCAB. Implied risk difference of 0.4% (with a 95% confidence interval, -3.6 to 4.4) showed nonsignificance in a standard test for equality (P=0.83) and for noninferiority with an inferiority margin of 0.5% (P=0.49). At the 6-month follow-up, mortality was 4.7% compared with 4.2% (P=0.75). Both groups showed significant improvement in self-assessed health-related quality of life.

CONCLUSIONS

Both conventional coronary artery bypass grafting and OPCAB are safe procedures that improved the quality of life when performed in elderly patients. No major differences in intermediate-term outcomes were found. However, the noninferiority of OPCAB with the prespecified margin could not be confirmed.

Who can respond to treatment? Identifying patient characteristics related to heterogeneity of treatment effects

BACKGROUND

Interest in comparative effectiveness research and the rising number of negative or "small effect" trials have stimulated research into differential response to treatment among subgroups of patients.

OBJECTIVE

To develop and test the Potential for Benefit Scale (PBS), a composite measure to identify subgroups of patients with differential potential for response to treatment, using diabetes as a model.

DESIGN

Cross-sectional and longitudinal cohort study.

SUBJECTS AND SETTING

Type 2 diabetes patients (n = 1361) were identified from 7 outpatient clinics serving a diverse population. Of these, 611 completed a 1-year follow-up.

MEASURES

To represent patients' health status, we used the Total Illness Burden Index, the Physical Function Index of the SF-36, the Center for Epidemiologic Studies Depression Scale, and the Diabetes Burden Scale. To represent personality characteristics related to health, we used the Provider-Dependent Health Care Orientation scale. We assessed the contribution of these measures to a composite scale of patients' potential for treatment response in terms of self-reported medication adherence and glycemic control.

RESULTS

Principal components analysis confirmed associations among these measures. The internal consistency reliability of the PBS was adequate (Cronbach alpha = 0.65). Patients in the lowest versus highest quartile of the PBS reported poorer adherence (18% vs. 55%, P < 0.001) and poorer glycemic control at baseline (mean hemoglobin A1c values: 7.75 vs. 7.39, P < 0.001). Those in the highest quartile of the PBS also were more likely to reach target values for glycemic control (HbA1c <7%) at 1-year follow-up, (adjusted OR = 1.61, P < 0.05).

CONCLUSIONS

The PBS, a composite scale, may be helpful in identifying patients with differential potential for response to treatment.