The Addition of Cardiac Computed Tomography to Exercise Treadmill Testing in the Evaluation of Angina
试验速览
- 阶段
- 不适用
- 试验地点
- 1
研究概览
简要总结
The current outpatient evaluation for angina in low and intermediate risk patients typically starts with a functional assessment for coronary ischemia. Exercise treadmill testing is often selected as the initial diagnostic modality for coronary artery function. However, exercise treadmill testing is limited by its moderate sensitivity and specificity, often resulting in further cardiac resource utilization for patient risk stratification and reassurance. With the advent of coronary multislice computed tomography (MSCT) angiography, coronary artery anatomy can now be evaluated noninvasively. Despite its impressive performance characteristics, the role of coronary MSCT angiography in the outpatient evaluation of angina remains undefined.
CT-EXTRA compares the impact on patient safety and downstream resource utilization of a novel initial diagnostic strategy employing the addition of coronary MSCT angiography to exercise treadmill testing with a standard diagnostic strategy of exercise treadmill testing for the ambulatory evaluation of low-intermediate risk patients with possible angina. The study is a single center, prospective, non-blinded, randomized clinical trial. Men and women, age 18-70, with a low to intermediate pretest probability of coronary artery disease who are referred for an exercise treadmill test for angina are eligible. Subjects are randomized either to an initial diagnostic strategy of exercise treadmill testing or exercise treadmill testing with coronary MSCT angiography. Subsequent diagnostic testing and treatment are the discretion of the referring physician. Subjects will be clinically followed for 24 months.
The clinical impact on patient safety and downstream clinical resource utilization of this novel diagnostic strategy in which both coronary artery anatomy and function are initially evaluated will be determined. The primary outcome is a composite endpoint consisting of freedom from adverse cardiac events, further cardiac diagnostic testing, and future cardiac clinical encounters. Secondary outcomes include the impact on the indiscriminate use of coronary angiography, subject anxiety, depression, motivation for healthy behavioral change, and satisfaction with diagnostic evaluation and use of antiplatelet and antilipid therapy. Lastly, the cost effectiveness of the routine addition of coronary MSCT angiography in the outpatient evaluation of possible angina will be determined.
详细描述
CT-EXTRA is a randomized clinical trial that will compare a novel diagnostic strategy employing the addition of coronary MSCT angiography to exercise treadmill testing with a standard diagnostic strategy of exercise treadmill testing for the outpatient evaluation of low-intermediate risk patients with possible angina. This is the first randomized clinical trial that evaluates a diagnostic strategy for outpatient chest pain that incorporates a noninvasive assessment of both coronary artery function and anatomy. CT- EXTRA will determine whether coronary MSCT angiography adds any incremental prognostic value over exercise treadmill testing alone for predicting future adverse cardiac events and reduces downstream clinical resource utilization. This study will also evaluate the impact of this strategy on the avoidance of unnecessary invasive coronary angiography, statin and aspirin prescription, patient anxiety, satisfaction with the diagnostic approach, and motivation for healthy behavioral change. Finally, an economic analysis will be performed to assess the differences in overall healthcare costs between the diagnostic approaches. In today's managed care-dominated paradigm, it is paramount that a new diagnostic modality such as coronary MSCT angiography is not only clinically effective but cost effective as well. CT EXTRA will provide critical information to clinicians and health care administrators on the clinical and cost effectiveness of an initial diagnostic strategy employing routine coronary MSCT angiography in the evaluation of patients for possible angina.
300 male and female military health care beneficiaries between the ages of 18-70, who are low to intermediate risk for symptomatic coronary artery disease and are referred to the Walter Reed Cardiology Clinic for an exercise treadmill test for the evaluation of possible angina (chest pain or angina-equivalent).
This study is a randomized, non-blinded, prospective trial to be conducted in the Cardiology clinic at Walter Reed Army Medical Center. Patients, age 18-70 years, referred to the Cardiology clinic for an exercise treadmill test for an outpatient evaluation of possible angina and are low-intermediate risk for symptomatic coronary artery disease, will be eligible. All patients who meet the aforementioned inclusion/exclusion criteria will be consented by an investigator and randomized from sealed envelopes to either "mandatory coronary MSCT angiography" or "no coronary MSCT angiography" before initiation of exercise treadmill testing. The randomization sequence will be generated using a sequence of computer-generated random numbers. All consented subjects will complete surveys assessing baseline depression using the Beck Depression Inventory, anxiety using the State and Trait Anxiety Inventory, and motivation healthy behavioral change using the ladder scale questionnaire. Completion of these three questionnaires are for research purposes and will take approximately 15 minutes.
Exercise Treadmill Testing
All subjects will undergo exercise treadmill testing as initially ordered by the referring physician. All exercise treadmill testing will be conducted at the Cardiology clinic at Walter Reed Army Medical Center according to standard clinic protocol. Testing will be conducted by a health care professional (staff physician, fellow, or nurse practitioner) not associated with the protocol. A Cardiology staff physician not affiliated with the protocol will officially interpret each exercise treadmill test. Subjects will perform a graded exercise treadmill test according to a Full Bruce protocol aimed at reaching 85% of the maximal predicted heart rate for age. According to standard clinical practice, an exercise treadmill test is considered positive if 0.1 mV of new horizontal or downsloping ST segment depression or ST segment elevation 0.80 ms beyond the J point occurs during exercise or recovery in two or more contiguous lead. A nondiagnostic test is defined as the absence of ischemic electrical changes in the setting of reproduction of chest pain symptoms or when peak heart rate is ≤85 % of the age-predicted maximal heart rate. An exercise treadmill test is considered negative when > 85% of the age-predicted maximal heart rate is achieved and reproduction of anginal symptoms and development of electrocardiographic ischemic changes are absent. In accordance with standard clinical practice, exercise treadmill testing will be prematurely terminated in the event of lightheadedness, severe ST depression (>2mm) or elevation (>1mm), ventricular or supraventricular arrhythmias, exaggerated blood pressure increase (>250 mm Hg systolic or >120mm Hg diastolic) and a >10mm Hg decrease in diastolic blood pressure. Upon completion of exercise treadmill testing, the subject will be provided a copy of the results and official interpretation of the exercise treadmill test for inclusion in their medical records. A copy of the exercise treadmill test results will be kept in the subject's file for the investigational team. Completion of an exercise treadmill test generally takes about 25 minutes.
研究设计
- 研究类型
- Observational
- 观察模型
- Natural History
- 时间视角
- Prospective
入排标准
- 年龄范围
- 18 Years 至 70 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Chest pain or anginal equivalent symptoms possibly suggestive of symptomatic coronary artery disease.
- •Low-intermediate risk (<75% pretest probability) for symptomatic coronary artery disease on basis of age, sex, and quality of reported symptom as classified by the Diamond and Forrester scheme6
- •Referred to Walter Reed Cardiology clinic for an exercise treadmill test as the initial diagnostic test of choice
- •Age equal to or greater than 18 years and less than 70 years
- •Ability to provide informed consent
排除标准
- •Abnormal baseline electrographic changes that would preclude proper diagnosis of ischemia including preexcitation (Wolff-Parkinson-White) syndrome, a paced ventricular rhythm, more than 1 mm of ST depression at rest, complete left bundle branch block, or criteria for left ventricular hypertrophy, even if they have less than 1 mm of baseline ST depression
- •Presence of known pre-existing coronary artery disease (known prior myocardial infarction, EKG evidence of prior infarction, prior angiographic evidence of significant coronary artery disease, history of prior coronary revascularization).
- •Previous outpatient or inpatient evaluation for coronary artery disease to include exercise treadmill testing, stress echocardiography or nuclear myocardial perfusion studies within the last three years.
- •Presence of signs or symptoms that are clearly compatible with non-cardiac chest pain, including musculoskeletal, gastrointestinal or neuropathic causes.
- •Renal insufficiency (creatinine >1.5mg/dl) or renal failure requiring dialysis.
- •Baseline heart rate > 100bpm, atrial fibrillation or other markedly irregular rhythm (frequent ectopy, multifocal atrial tachycardia) on baseline ECG.
- •Pregnancy or unknown pregnancy status.
- •Known allergy to iodinated contrast.
- •Inability to tolerate beta-blocking drugs, including patients with reactive airways disease requiring maintenance inhaled bronchodilators or steroids, complete heart block or second-degree atrioventricular block.
- •Patients with hyperthyroidism including Grave's disease and toxic multinodular goiter
- •Computed tomography imaging, or iodinated contrast administration over 50 ml, within the past 48 hours.
- •Unwillingness to withhold ingestion of metformin or commonly used erectile dysfunction medications (Viagra, Cialis, Levitra) for 48 hours prior to MSCT scan.
- •Previous history of radiation therapy to the thorax.