- Email: [email protected]
MY APPROACH to the use of CT in triage of chest pain in the ED
Author's Accepted Manuscript
MY APPROACH to the use of CT in triage of chest pain in the ED Ron Blankstein MD, FACC
www.elsevier.com/locate/tcm
PII: DOI: Reference:
S1050-1738(16)30034-2 http://dx.doi.org/10.1016/j.tcm.2015.10.011 TCM6288
To appear in: trends in cardiovascular medicine
Cite this article as: Ron Blankstein MD, FACC, MY APPROACH to the use of CT in triage of chest pain in the ED, trends in cardiovascular medicine, http: //dx.doi.org/10.1016/j.tcm.2015.10.011 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
MY APPROACH to the Use of CT in Triage of Chest Pain in the ED*
Ron Blankstein, MD, FACC
My approach to use of CT in triage of chest pain in the emergency department (ED) centers on selecting patients who would clinically benefit from coronary CT angiography (CTA) and who can undergo this exam safely while having excellent quality images. Patients who present to the ED with chest pain can benefit from coronary CTA if they have no prior history of coronary artery disease (CAD) and there is a clinical concern for a possible acute coronary syndrome (ACS). In such patients, the high negative predictive value of CTA (>95%) can be useful for rapidly ruling out any CAD and identifying individuals who can be sent home immediately and who have a very low risk of future events. However, no test is perfect for everyone. Patients who have a very low risk (ie, young patients and/or when there is a clear alternative diagnosis for their symptoms) or a high risk of an acute coronary syndrome (ie, dynamic EKG changes or elevated troponin) would not be appropriate. In addition, patients who are older (age >70 years) or who have multiple risk factors for CAD may derive greater benefit from functional testing, particularly if they are already on preventive medical therapies, and the main clinical question is if their presenting symptoms are due to ischemia and if they would benefit from coronary revascularization. In such cases, if coronary CTA is performed and a significant amount of plaque is found, it may be difficult to determine the functional significance associated with their anatomical lesions. In addition, if extensive coronary
calcifications are present, this may limit the accuracy of CTA to estimate the severity of luminal narrowing. Patients who cannot hold their breath or who have elevated heart rates which cannot be controlled with beta blockers should not undergo CTA as the image quality will be impaired. In addition, in patients with morbid obesity (BMI >40 kg/m ) diagnostic image quality is less likely, and additional testing options should be considered. CTA cannot be performed in individuals with impaired renal function (GFR <30–45 mL/min). A unique advantage of CTA is that the test can be performed rapidly since only one set of cardiac enzymes is required prior to testing and the fact that the exam itself is very rapid (patient preparation in the scanner room may take approximately 15 minutes and actual image acquisition takes a few seconds). As a result, randomized studies have consistently shown that, compared with other testing strategies, use of CTA leads to a more rapid discharge from the ED and consequently lower ED costs. Hospital costs may also be lowered but are sensitive to how often additional downstream testing is required. It is important to know how to utilize the results of CTA in patient decision-making. Patients who have no coronary plaque or stenosis (“a normal CTA”) can be safely and rapidly discharged home and be reassured that their risk of future coronary heart disease events is extremely low. If such patients return to the ED with chest pain, an alternative diagnosis for their symptoms should be explored, as further cardiac testing is unlikely to be useful. Patients who are found to have nonobstructive plaque (<50% stenosis) would benefit from having a second set of cardiac enzymes checked since rarely an ACS may present with nonobstructive plaque. Following two negative sets of enzymes, most patients can be safely discharged home, although other CT markers of increased risk can be considered (eg, amount and extent of plaque; presence of resting myocardial perfusion defects). Patients with nonobstructive plaque, especially if extensive, would benefit from initiation of preventive therapies and should have a follow-up outpatient appointment to implement lifestyle and pharmacologic therapies for CAD. All patients who are found to have moderate stenosis (ie, 50%–70%), and some patients 2
with severe stenosis (>70%), would benefit from functional testing to evaluate the presence and severity of ischemia. Since the use of coronary CTA is associated with a slightly higher frequency of undergoing invasive angiography and coronary revascularization, it is important to ensure that ischemia is present before considering such procedures. In summary, coronary CTA represents a safe, accurate, and rapid technique to evaluate patients without known CAD who present to the ED with symptoms concerning for an ACS. Nevertheless, it is always important to consider if testing is needed, and, if so, how will this impact patient management. It is also important to know the availability and local expertise of other testing options. Associate Professor, Medicine and Radiology, Harvard Medical School; Associate Physician, Departments of Medicine (Cardiovascular Division) and Radiology, Brigham and Women’s Hospital; Co-Director, Cardiovascular Imaging Training Program, Director, Cardiac Computed Tomography, Brigham and Women’s Hospital, Boston, Massachusetts
Email:
[email protected]
*First published on PracticeUpdate on September 14, 2015. Republished with permission.
MY APPROACH to the use of CT in triage of chest pain in the ED Ron Blankstein MD, FACC
www.elsevier.com/locate/tcm
PII: DOI: Reference:
S1050-1738(16)30034-2 http://dx.doi.org/10.1016/j.tcm.2015.10.011 TCM6288
To appear in: trends in cardiovascular medicine
Cite this article as: Ron Blankstein MD, FACC, MY APPROACH to the use of CT in triage of chest pain in the ED, trends in cardiovascular medicine, http: //dx.doi.org/10.1016/j.tcm.2015.10.011 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
MY APPROACH to the Use of CT in Triage of Chest Pain in the ED*
Ron Blankstein, MD, FACC
My approach to use of CT in triage of chest pain in the emergency department (ED) centers on selecting patients who would clinically benefit from coronary CT angiography (CTA) and who can undergo this exam safely while having excellent quality images. Patients who present to the ED with chest pain can benefit from coronary CTA if they have no prior history of coronary artery disease (CAD) and there is a clinical concern for a possible acute coronary syndrome (ACS). In such patients, the high negative predictive value of CTA (>95%) can be useful for rapidly ruling out any CAD and identifying individuals who can be sent home immediately and who have a very low risk of future events. However, no test is perfect for everyone. Patients who have a very low risk (ie, young patients and/or when there is a clear alternative diagnosis for their symptoms) or a high risk of an acute coronary syndrome (ie, dynamic EKG changes or elevated troponin) would not be appropriate. In addition, patients who are older (age >70 years) or who have multiple risk factors for CAD may derive greater benefit from functional testing, particularly if they are already on preventive medical therapies, and the main clinical question is if their presenting symptoms are due to ischemia and if they would benefit from coronary revascularization. In such cases, if coronary CTA is performed and a significant amount of plaque is found, it may be difficult to determine the functional significance associated with their anatomical lesions. In addition, if extensive coronary
calcifications are present, this may limit the accuracy of CTA to estimate the severity of luminal narrowing. Patients who cannot hold their breath or who have elevated heart rates which cannot be controlled with beta blockers should not undergo CTA as the image quality will be impaired. In addition, in patients with morbid obesity (BMI >40 kg/m ) diagnostic image quality is less likely, and additional testing options should be considered. CTA cannot be performed in individuals with impaired renal function (GFR <30–45 mL/min). A unique advantage of CTA is that the test can be performed rapidly since only one set of cardiac enzymes is required prior to testing and the fact that the exam itself is very rapid (patient preparation in the scanner room may take approximately 15 minutes and actual image acquisition takes a few seconds). As a result, randomized studies have consistently shown that, compared with other testing strategies, use of CTA leads to a more rapid discharge from the ED and consequently lower ED costs. Hospital costs may also be lowered but are sensitive to how often additional downstream testing is required. It is important to know how to utilize the results of CTA in patient decision-making. Patients who have no coronary plaque or stenosis (“a normal CTA”) can be safely and rapidly discharged home and be reassured that their risk of future coronary heart disease events is extremely low. If such patients return to the ED with chest pain, an alternative diagnosis for their symptoms should be explored, as further cardiac testing is unlikely to be useful. Patients who are found to have nonobstructive plaque (<50% stenosis) would benefit from having a second set of cardiac enzymes checked since rarely an ACS may present with nonobstructive plaque. Following two negative sets of enzymes, most patients can be safely discharged home, although other CT markers of increased risk can be considered (eg, amount and extent of plaque; presence of resting myocardial perfusion defects). Patients with nonobstructive plaque, especially if extensive, would benefit from initiation of preventive therapies and should have a follow-up outpatient appointment to implement lifestyle and pharmacologic therapies for CAD. All patients who are found to have moderate stenosis (ie, 50%–70%), and some patients 2
with severe stenosis (>70%), would benefit from functional testing to evaluate the presence and severity of ischemia. Since the use of coronary CTA is associated with a slightly higher frequency of undergoing invasive angiography and coronary revascularization, it is important to ensure that ischemia is present before considering such procedures. In summary, coronary CTA represents a safe, accurate, and rapid technique to evaluate patients without known CAD who present to the ED with symptoms concerning for an ACS. Nevertheless, it is always important to consider if testing is needed, and, if so, how will this impact patient management. It is also important to know the availability and local expertise of other testing options. Associate Professor, Medicine and Radiology, Harvard Medical School; Associate Physician, Departments of Medicine (Cardiovascular Division) and Radiology, Brigham and Women’s Hospital; Co-Director, Cardiovascular Imaging Training Program, Director, Cardiac Computed Tomography, Brigham and Women’s Hospital, Boston, Massachusetts
Email:
[email protected]
*First published on PracticeUpdate on September 14, 2015. Republished with permission.