Stress testing of households using micro-data: evidence from a developing country

Of all stress tests done in low risk Emergency Department observation units (OU), a small, but significant number may be reported as positive or indeterminate. The objective of this study is to quantify the prevalence and costs associated with positive and indeterminate stress tests that result in negative cardiac catheterization. Retrospective observational cohort study over 9 months. All patients undergoing the chest pain protocol who got cardiac stress testing in the OU were eligible for inclusion. Cost data were derived from an institutional activity-based cost system utilizing actual costs. Chart review was completed on all patients with positive and indeterminate stress tests and a randomly chosen sample of those with negative stress tests. Of the 1194 patients who met the inclusion criteria, 1084 (90.8%) had a negative stress test. Sixty-two (5.2%) had a positive stress test, and 48 (4.0%) had an indeterminate stress test. Of all 59 patients who underwent catheterization, 41 (69.5%) were negative cardiac catheterizations. The prevalence among all OU stress test patients of positive or indeterminate stress tests with subsequent negative cardiac catheterization was 41/1194 (3.4%; 95% CI 2.5%-4.6%). The prevalence of significant coronary artery disease at cardiac catheterization was 18/1194 (1.5%; 95% CI 1.0%-2.4%). Patients with a positive or indeterminate stress test who had a negative catheterization incurred increased OU costs ($1385 vs. $1,039, P = 0.012), total costs ($7298 vs. $1562, P < 0.001) and length of inpatient stay (1.83 days vs. 0.00 days) when compared with those who had a negative stress test. The probability of going to the OU and having a positive or indeterminate stress test resulting in a subsequent negative catheterization was double the probability of having a stress test result in catheterization that detected significant coronary artery disease. These patients incurred 5 times the total cost when compared with those patients with negative stress testing. Further investigation is warranted to determine alternative risk stratification methods for these low risk chest pain patients with positive stress tests.

Prior studies demonstrating shorter length of stay (LOS) from coronary computed tomography angiography (CCTA) relative to stress testing in emergency department (ED) patients have not considered time of patient presentation. The objectives of this study were to determine whether low-risk chest pain patients receiving stress testing or CCTA have differences in ED plus observation unit (OU) LOS and if there are disparities in testing modality use, based on the time of patient presentation to the ED. The authors examined a cohort of low-risk chest pain patients evaluated in an ED-based OU using prospective and retrospective OU registry data. During the study period, stress testing and CCTA were both available from 08:00 to 17:00 hours. CCTA was not available on weekends, and therefore only subjects presenting on weekdays were included. Cox regression analysis was used to model the effect of testing modality (stress testing vs. CCTA) on OU LOS. Separate models were fit based on time of patient presentation to the ED using 4-hour blocks beginning at midnight. The primary independent variable was testing modality: stress testing or CCTA. Age, sex, and race were included as covariates. Logistic regression was used to model testing modality choice by time period adjusted for age, sex, and race. Over the study period, 841 subjects presented Monday through Friday. Median LOS was 18.0 hours (interquartile range [IQR] = 11.7 to 22.9 hours). Objective cardiac testing was completed in 788 of 841 (94%) patients, with 496 (63%) receiving stress testing and 292 (37%) receiving CCTA. After age, race, and sex were adjusted for, patients presenting between 08:00 and 11:59 hours not only had a shorter LOS associated with CCTA (p < 0.0001), but also had a greater likelihood of being tested by CCTA (p = 0.001). None of the other time periods had significant differences in LOS or testing modality choice for CCTA relative to stress testing. In an OU setting with weekday and standard business hours CCTA availability, CCTA testing was associated with shorter LOS among low-risk chest pain patients only in patients presenting to the ED between 08:00 and 11:59 hours. That time period was also associated with a greater likelihood of being tested by CCTA, suggesting that ED providers may have intuited the inability of CCTA to shorten LOS during other times.

41: Utility of Cardiac Stress Testing In Young Patients In an Observation Unit

Highlights From the Circulation Family of Journals.

Up to 60% of patients in the US receive a stress test within 2 years of percutaneous coronary intervention (PCI), prompting concerns about the possible overuse of stress testing. To examine the proportion of patients who underwent stress testing within 2 years of elective PCI, proportion of patients who had symptoms that were consistent with coronary artery disease (CAD), timing of stress testing, and site-level variation in stress testing among symptomatic and asymptomatic patients. This cohort study used administrative claims data and clinical records from the US Department of Veterans Affairs (VA) Clinical Assessment, Reporting, and Tracking program. Patients who underwent stress testing within 2 years of elective PCI for stable CAD between November 1, 2013, and October 31, 2015, at 64 VA facilities were included in the analysis. Patients who received stress testing for staging purposes, cardiac rehabilitation evaluation, or preoperative testing before high-risk surgery were excluded. Data were analyzed from June to December 2020. The main outcome was the proportion of patients who underwent stress testing and had symptoms that were consistent with obstructive CAD, using definitions from the 2013 clinical practice guideline (Multimodality Appropriate Use Criteria for the Detection and Risk Assessment of Stable Ischemic Heart Disease). Secondary outcomes were the timing of stress testing (assessed using a cumulative incidence curve) and site-level variation in stress testing (assessed using multilevel logistic regression models). A total of 3705 consecutive patients (mean [SD] age 66.3 [7.6] years; 3656 men [98.7%]; 437 Black individuals [11.8%], 3175 White individuals [85.7%], and 93 individuals [2.5%] of other races and ethnicities [Asian, Hispanic or Latinx, or unknown]) had elective PCI. Of these patients, 916 (24.7%) received a stress test within 2 years, among whom 730 (79.7%) had symptoms that were consistent with obstructive CAD at the time of stress testing. Visual inspection of a cumulative incidence curve for stress testing showed no rapid increases in stress testing at 6 months or 1 year after PCI, which might coincide with routine clinical visits. The proportion of symptomatic patients who underwent stress testing at each VA site ranged from 67.7% to 100%, with no significant site-level variation in stress testing. Results of this study suggest that most veterans who underwent stress testing within 2 years after elective PCI had symptoms that were consistent with obstructive CAD. Therefore, measuring low-value stress testing using only administrative claims data may overestimate its prevalence, and concerns about overuse of post-PCI stress testing may be overstated.

TREADMILL STRESS TEST VENTILATORY PATTERN USING A WEARABLE DEVICE AS AN ADDITIONAL MARKER FOR CV DISEASE

For myocardial perfusion imaging (MPI), the best test to evaluate hemodynamic changes during stress is an exercise treadmill test. It provides independent prognostic value, including evaluation of total exercise time, performance, and capacity; heart rate response during exercise, with ischemia, and in recovery; blood pressure response; myocardial oxygen demand; and assessment of symptoms. Combining these exercise data with perfusion imaging provides the best prognostic value and risk stratification for patients. Although exercise stress testing accompanied by MPI is preferential, it is not always possible since an increasing number of patients cannot exercise to a maximal (symptom-limited) level. Further, there is much evidence in the literature demonstrating a suboptimal, non-symptom-limited (not achieving at least 4-6 min or <85% of maximum predicted heart rate) exercise test performed as part of an MPI study may result in a false-negative outcome. Therefore, pharmacologic stress agents provide an excellent alternative for those patients who cannot achieve an adequate heart rate response or adequately perform physical exercise. This article focuses on considerations for performing stress (exercise and pharmacologic) testing in conjunction with MPI. It is meant to provide a basic overview of the principles of exercise stress testing; discuss the indications, contraindications, patient preparation, and protocols for exercise stress testing; discuss the contraindications, administration protocols, and side effects for vasodilator (adenosine, dipyridamole, and regadenoson) stress testing; and discuss the contraindications, administration protocols, and side effects for dobutamine stress testing.

Stress testing is integral to evaluate patients with heart disease. However, few data are available regarding safety of stress testing in patients with implantable cardioverter defibrillators (ICDs). Some exercise laboratories consider maximal exercise stress testing and pharmacologic stress testing with dobutamine contraindications in patients with ICDs and some laboratories inactivate ICDs prior to stress testing. PURPOSE The aim of this retrospective study was to assess the safety and feasibility of exercise and pharmacologic stress testing (PST) in patients with ICDs. METHODS Patients with ICD implantation and subsequent stress testing were included in this analysis. Chart review was performed. Primary end-points were occurrence of malignant ventricular arrhythmias (MVAs), onset of burst pacing or ICD firing, cardiopulmonary resuscitation (CPR) or death during stress testing. Secondary end-points were need for urgent coronary revascularization based on stress testing results and hospital readmissions for MVAs. RESULTS From January 1999 to December 2003, 1734 patients underwent ICD implantation or generator replacement. A total of 84 patients subsequently underwent 107 stress tests at William Beaumont Hospital, Royal Oak. Mean age was 67±12 years and 76% were men. Indications for ICD implantation were dilated cardiomyopathy (51%), sustained ventricular tachycardia (39%), sudden cardiac death (8%) and long QT syndrome (1%). 41% underwent exercise stress testing and 59% underwent PST utilizing dobutamine (21%) or dipyridamole (38%). Left ventricular ejection fraction was 32±20. 71% had fixed defects and 22% had reversible perfusion defects as determined by myocardial perfusion imaging. None of the ICDs were inactivated prior to stress testing. Heart rate at peak stress averaged 92±27 beats per minute. 83% were on beta-receptor antagonists. Although 4% of patients had self-terminating, non-sustained ventricular tachycardia at peak stress, none had sustained ventricular tachycardia precipitating burst pacing, ICD shock, CPR or death. One patient underwent urgent coronary angiography, but was found to have non-critical coronary disease. There were no hospital readmissions for MVAs. CONCLUSIONS These preliminary findings suggest that stress testing can be performed safely in patients with ICDs. MVAs requiring emergent treatment are rare occurrences during stress testing. Knowledge of programmed ventricular tachycardia and ventricular fibrillation zones may help predetermine maximal heart rates on stress testing and preclude routine inactivation of ICDs prior to testing.

Stress testing before abdominal aortic aneurysm repair does not lead to a reduction in perioperative cardiac events

Preoperative Stress Test and Postoperative MI in Patients Requiring Lower Extremity Bypass for Critical Limb Ischemia

The appropriate use criteria considers cardiac stress testing within 2 years after percutaneous coronary intervention (PCI) to be rarely appropriate, unless prompted by symptoms or change in clinical status. Little is known about the patterns of cardiac stress testing after PCI in the single-payer Canadian healthcare system, where mechanisms for reimbursement are different from the United States. Frequency and timing of cardiac stress testing within 2 years of PCI performed between April 2004 and March 2013 in Ontario, Canada, was determined from linked provincial databases. Subsequent rates of coronary angiography and revascularization after stress testing were ascertained. Of the 112 691 patients with PCI, 67 442 (59.8%) underwent at least 1 stress test, with 38 267 (34.0%) undergoing repeat stress testing (ie, >1 stress test) within 2 years. Patients who underwent stress testing were younger, had less medical comorbidities, were more likely to reside in urban areas, and had higher incomes. Spikes in incidence of repeat stress testing were observed at 3 to 4 months, 6 to 7 months, and 12 to 13 months after the prior stress test. Of those tested, only 5.9% underwent subsequent coronary angiography, and only 3.1% underwent repeat revascularization within 60 days of stress testing. More than half of all patients undergo cardiac stress testing within 2 years of PCI, with one third undergoing repeat stress tests. Only 1 of 30 tested patients underwent repeat revascularization. These findings reinforce the appropriate use criteria recommendations against routine stress testing after PCI. Further work is needed to aid with the selection of patients most likely to benefit from stress testing after PCI.

Stress Test is forward looking simulation exercise to assess resilience of financial institutions in the midst of sever but plausible adverse scenario.Liquidity Stress testing is an important means for sketching out acomprehensive picture of liquidity risk profile of an institution. Stress testing is a powerful tool in the hands of Liquidty risk managers.Liquidity stress testing involves weighing potential net liquidity outflow exposures under stressed scenarios vis a vis the available counterbalancing capacity. Varying behaviour of fund providers and users in different stress situations based on their market and solvency perception of the concerned institutions necessitates measurement and management of liquidity risk scenario specific. Identification of cash-flow drivers is perhaps the most crucial step in defining and structuring the scenario parameters. Deterministic stress test pivots on assumptions and methods. The set of assumptions have to be as realistic as possible ensuring proper alignment in an internally consistent way. The stress test outcomes help in identification of severe vulnerabilities. The method however involves subjectivity throwing ideas about loss severity without any estimate of associated chance and probability of occurrence thereof. Stress Tests based on hypothetical data and assumptions are useful but not accurate. Stress testing provides where withal for formulation of the plan to tackle effectively liquidity problems as when arising. Stress testing work as effective tool provided its outcomes and findings are properly evaluated and incorporated in the strategic plan. Stress testing is not the ultimate! Instead it forms only a component of dynamic and integrated liquidity risk management process. However, stress testing is definitely an effective tool providing valuable inputs to risk management decisions provided it is sufficiently embedded and aligned to risk management frameworks and senior management decision making frameworks.

In-situ reservoir stress measurements are essential input to a wide variety of the production and injection applications of reservoirs. Most of the reservoirs in this article require water injection to maximize recovery without breaking the matrices unintentionally. In some cases, it is also important to create a controlled fracture growth in a formation unit without breaking bordering barriers or zones. The main purpose of the in-situ reservoir stress testing of the case studies in this article is to calculate the minimum stress to improve the reservoir management plans for well placement, production, injection and fracturing processes. One approach of measuring stresses in many zones is to use the wireline conveyed stress testing tools. The wireline conveyed in-situ reservoir stress testing measurements are frequently performed in the Sultanate of Oman for a wide range of operational and geomechanics applications such as but not limited to:Hydraulic fracturingFracture growth/containment issuesPolymer injectionBorehole stabilitySand production predictionStress evolution with depletion, hot and cold injection The stress testing zones vary from tight to high permeable zones as well as shale zones. The complexity and wide variety of the stress testing applications inevitably led modifications and improvements on the wireline conveyed stress testing tools. These improvements mainly are various types of pumps, higher performance dual packers and mandrels, innovative stress testing methods. The latest improvements and methods in stress testing help addressing the broader range of formations (deep and shallow, tight and permeable) in an extensive type of wells from vertical or deviated to horizontal. In this article, the examples of several unique stress testing applications are presented. Shale stress testing with a viscous fluid, horizontal well stress testing, tight and very high permeability formation stress testing, sleeve fracturing stress testing methods are discussed in details. Introduction In-situ stress magnitude and direction measurements in vertical and lateral directions are required in a reservoir for several reasons. These are for hydraulic fracture design, fracture type identification, water and gas injection management, fault activity, wellbore stability, sand production, rock mechanical properties, casing strings design, cap and base rock integrity, subsidence, and gas storage design.

In-situ reservoir stress measurements are essential input to a wide variety of the production and injection applications of reservoirs.Most of the reservoirs in this article require water injection to maximize recovery without breaking the matrices unintentionally. In some cases,it is also important to create a controlled fracture growth in a formation unit without breaking bordering barriers or zones.The main purpose of the in-situ reservoir stress testing of the case studies in this article is to calculate the minimum stress to improve the reservoir management plans for well placement, production,injection and fracturing processes. One approach of measuring stresses in many zones is to use the wireline conveyed stress testing tools. The wireline conveyed in-situ reservoir stress testing measurements are frequently performed in the Sultanate of Oman for a wide range of operational and geomechanics applications such as but not limited to: Hydraulic fracturingFracture growth/containment issuesPolymer injectionBorehole stabilitySand production predictionStress evolution with depletion, hot and cold injection The stress testing zones vary from tight to high permeable zones as well as shale zones. The complexity and wide variety of the stress testing applications inevitably led modifications and improvements on the wireline conveyed stress testing tools. These improvements mainly are various types of pumps, higher performance dual packers and mandrels, innovative stress testing methods. The latest improvements and methods in stress testing help addressing the broader range of formations (deep and shallow,tight and permeable) in an extensive type of wells from vertical or deviated to horizontal. In this article, the examples of several unique stress testing applications are presented. Shale stress testing with a viscous fluid, horizontal well stress testing,tight and very high permeability formation stress testing, sleeve fracturing stress testing methods are discussed in details.

For many financial institutions, "stress tests" are an important input into processes that set risk capital allocations. In the current regulatory environment, two distinct model-based approaches for setting regulatory capital requirements include stress test components. The Basle internal models approach used by US banking regulators requires stress tests to augment VaR-based capital requirements. The US Congress has mandated that the regulatory risk-based capital requirements of the government-sponsored housing enterprises be based upon a stress test alone. This paper investigates the formal link between stress tests and risk capital in the context of an equilibrium model of a firm's capital structure. Two common approaches used to allocate capital under a stress test are examined. The results demonstrate that the stress testing approaches do not solve for an equity capital allocation that protects against default in stress scenarios. One approach produces biased estimates of the optimal debt-equity funding mix. The alternative approach estimates the minimum value of a portfolio of risk-free bonds that will "hedge" or fully insure stress scenario exposures. Neither approach estimates the equity component of an optimal capital structure. Because stress test procedures do not estimate the optimal debt-equity funding mix, stress test and VaR-based estimates of risk capital are not comparable. A modified stress test procedure can be used to set optimal equity capital allocations using stress test techniques that are comparable with VaR-based capital measures.