Related Experiment Videos
Diagnosis of acute cardiac ischemia
J Hector Pope1, Harry P Selker
1New England Medical Center, 750 Washington Street 163, Boston, MA, 02111, USA. jameshpope@aol.com
Insights
Diagnosing acute coronary syndromes (ACS) remains challenging. While prehospital ECGs and ACI-TIPI tools show promise in improving patient care and reducing hospitalizations, further research is needed for other diagnostic methods.
Area of Science:
- Cardiology
- Emergency Medicine
- Diagnostic Imaging
Background:
- Acute coronary syndromes (ACS) encompass unstable angina (UAP) and acute myocardial infarction (AMI), representing a continuum of acute coronary illness (ACI).
- Accurate identification of ACI is critical for patient outcomes and resource management, yet it poses significant diagnostic challenges for clinicians.
- Current diagnostic strategies often lead to over-admission of low-risk patients due to concerns about missing acute ischemia.
Purpose of the Study:
- To review the diagnostic accuracy and clinical impact of various technologies used in identifying acute coronary syndromes (ACS).
- To evaluate the effectiveness of different diagnostic tools in distinguishing ACI from other conditions and their impact on patient management.
- To highlight the need for further research into the clinical utility of emerging diagnostic technologies for ACS.
Main Methods:
- Review of existing literature on diagnostic technologies for acute coronary syndromes (ACS).
- Analysis of studies evaluating the sensitivity, specificity, and clinical impact of tools like prehospital ECG, ACI-TIPI, Goldman protocol, biomarkers, and imaging modalities.
- Focus on studies assessing the impact on hospitalization rates, time to treatment, and patient outcomes.
Main Results:
- Prehospital 12-lead ECGs demonstrate moderate accuracy and reduce time to treatment.
- The ACI-TIPI tool, in large trials, reduced unnecessary hospitalizations without compromising appropriate ACS admissions.
- Single biomarker measurements have low sensitivity for AMI, but serial measurements improve sensitivity; biomarkers are less effective for UAP. Advanced imaging shows potential but requires more study.
Conclusions:
- Effective diagnosis of ACS requires a multi-faceted approach, integrating clinical assessment with appropriate diagnostic tools.
- Tools like prehospital ECG and ACI-TIPI offer tangible benefits in managing patients with suspected ACS.
- Further research is essential to validate the clinical impact and cost-effectiveness of advanced diagnostic technologies in diverse patient populations.
Abstract:
A better understanding of coronary syndromes allow physicians to appreciate UAP and AMI as part of a continuum of ACI. ACI is a life-threatening condition whose identification can have major economic and therapeutic importance as far as threatening dysrhythmias and preventing or limiting myocardial infarction size. The identification of ACI continues to challenge the skill of even experienced clinicians, yet physicians continue (appropriately) to admit the overwhelming majority of patients with ACI; in the process, they admit many patients without acute ischemia [2], overestimating the likelihood of ischemia in low-risk patients because of magnified concern for this diagnosis for prognostic and therapeutic reasons. Studies of admitting practices from a decade ago have yielded useful clinical information but have shown that neither clinical symptoms nor the ECG could reliably distinguish most patients with ACI from those with other conditions. Most studies have evaluated the accuracy of various technologies for diagnosing ACI, yet only a few have evaluated the clinical impact of routine use. The prehospital 12-lead ECG has moderate sensitivity and specificity for the diagnosis of ACI. It has demonstrated a reduction of the mean time to thrombolysis by 33 minutes and short-term overall mortality in randomized trials. In the general ED setting, only the ACI-TIPI has demonstrated, in a large-scale multicenter clinical trial, a reduction in unnecessary hospitalizations without decreasing the rate of appropriate admission for patients with ACI. The Goldman chest pain protocol has good sensitivity for AMI but was not shown to result in any differences in hospitalization rate, length of stay, or estimated costs in the single clinical impact study performed. The protocol's applicability to patients with UAP has not been evaluated. Single measurement of biomarkers at presentation to the ED has poor sensitivity for AMI, although most biomarkers have high specificity. Serial measurements can greatly increase the sensitivity for AMI while maintaining their excellent specificity. Biomarkers cannot identify most patients with UAP. Finally, diagnostic technologies to evaluate ACI in selected populations, such as echocardiography, sestamibi perfusion imaging, and stress ECG, may have very good to excellent sensitivity; however, they have not been sufficiently studied.