Efficacy of multi-detector coronary computed tomography angiography in comparison with exercise electrocardiogram in the triage of patients of low risk acute chest pain

Objectives

To compare the safety and diagnostic efficacy of coronary computed tomography angiography (CTA) with exercise electrocardiography (XECG) in triaging patients of low risk acute chest pain.

Background

Noninvasive assessment of coronary stenosis by CTA may improve early and accurate triage of patients presenting with acute chest pain to the emergency department (ED).

Methods

Low risk patients of possible acute coronary syndrome (ACS) were included in the study. The patients in CTA arm with significant stenosis (≥50%) underwent catheterization, while those with no or intermediate stenosis (<50%) were discharged from ED and followed up periodically for six months for major adverse cardiovascular events (MACE). The same protocol was applied for XECG arm. Outcomes included: safety and diagnostic efficacy.

Results

A total of 81 (41 CTA and 40 XECG) patients were enrolled. In this study CTA was observed to be 100% sensitive and 95.7% specific in diagnosing MACE in low risk patients of chest pain presenting to the ED, with a PPV of 94.7% and an NPV of 100%.The overall diagnostic efficacy was 97.6%. XECG was observed to be 72.7% sensitive and 96.6% specific in diagnosing MACE with a PPV of 88.9% and NPV of 90.3% in low risk chest pain patients presenting to the ED. The overall diagnostic accuracy was 90%.

Conclusion

CTA is an excellent diagnostic tool in ED patients with low risk of ACS, with minimum time delay as compared to XECG, and also is safe for triaging such patients.     

Exercise performance-based outcomes of medically treated patients with coronary artery disease and profound ST segment depression

OBJECTIVES

We sought to determine the relationship between exercise duration and cardiovascular outcomes in patients with profound (≥2 mm) ST segment depression during exercise treadmill testing (ETT).

BACKGROUND

Patients with stable symptoms but profound ST segment depression during ETT are often referred for a coronary intervention on the basis that presumed severe coronary artery disease (CAD) will lead to unfavorable cardiovascular outcomes, irrespective of symptomatic and functional status. We hypothesized that good exercise tolerance in such patients treated medically is associated with favorable long-term outcomes.

METHODS

We prospectively followed 203 consecutive patients (181 men; mean age 73 years) with known stable CAD and ≥2 mm ST segment depression who are performing ETT according to the Bruce protocol for an average of 41 months. The primary end point was occurrence of myocardial infarction (MI) or death.

RESULTS

Eight (20%) of 40 patients with an initial ETT exercise duration ≤6 min developed MI or died, as compared with five (6%) of 84 patients who exercised between 6 and 9 min and three (3.8%) of 79 patients who exercised ≥9 min (p = 0.01). Compared with patients who exercised ≤6 min, increased ETT duration was significantly associated with a reduced risk of MI/death (6 to 9 min: relative risk [RR] = 0.25, 95% confidence interval [CI] 0.08 to 0.76; >9 min: RR = 0.14, 95% CI 0.04 to 0.53). This protective effect persisted after adjustment for potentially confounding variables. We observed a 23% reduction in MI/death for each additional minute of exercise the patient was able to complete during the index ETT.

CONCLUSIONS

Optimal medical management in stable patients with CAD with profound exercise-induced ST segment depression but good ETT duration is an appropriate alternative to coronary revascularization and is associated with low rates of MI and death.     

Prognostic value of pharmacological stress echocardiography in women with chest pain and unknown coronary artery disease

Objectives. In this study we sought to investigate the prognostic value of pharmacological stress echocardiography in women referred for chest pain, having unknown coronary artery disease.

Background. The noninvasive identification of a high-risk subgroup among women with chest pain and unknown coronary artery disease is an unresolved task to date.

Methods. A total of 456 women (mean [±SD] age 63 ± 10 years) underwent pharmacological stress echocardiography with either dipyridamole (n = 305) or dobutamine (n = 151) for evaluation of chest pain and were followed-up for 32 ± 19 months. None of them had a previous diagnosis of coronary artery disease.

Results. No major complication occurred during stress testing. Five tests (1.1%) were prematurely interrupted because of the appearance of side effects. Echocardiographic positivity was identified in 51 patients. During the follow-up, 23 cardiac events occurred: 3 deaths, 10 infarctions and 10 cases of unstable angina; an additional 21 patients underwent coronary revascularization. At Cox analysis, the echocardiographic evidence of ischemia was found as the only independent predictor of hard cardiac events (death, infarction) (odds ratio [OR] = 27.5; 95% confidence interval [CI] = (6.5 to 115.5; p = 0.0000). When spontaneous cardiac events (death, infarction and unstable angina) were considered as endpoints, the positive echocardiographic result (OR = 23.9; 95% CI = 8.6 to 66.8; p = 0.0000) and family history of coronary artery disease (OR = 3.7; 95% CI = 1.5 to 9.1; p = 0.0037) were independently correlated with prognosis. By using an interactive stepwise procedure, the prognostic value of stress echocardiography was found to be incremental to that provided by clinical variables, both considering hard and spontaneous cardiac events as endpoints. The 3-year survival rate for the negative and the positive population was respectively, 99.5% and 69.5% (p = 0.0000) considering hard cardiac events, 99.2% and 50.6% (p = 0.0000) considering spontaneous cardiac events.

Conclusions. Pharmacological stress echocardiography is safe, highly feasible and effective in risk stratification of women with chest pain and unknown coronary artery disease, also when hard endpoints are considered. Its use can have relevant implications in daily clinical practice for selection of patients needing further investigations.     

Significance of reduced uptake of iodinated fatty acid analogue for the evaluation of patients with acute chest pain

OBJECTIVES

To assess whether 15-(p-[iodine-123] iodophenyl)-3-(R,S) methylpentadecanoic acid (BMIPP) imaging can identify previous ischemic areas, BMIPP SPECT was performed in patients with acute chest pain to compare its findings with those of technetium-99m–tetrofosmin (tetrofosmin) SPECT and coronary angiography.

BACKGROUND

Basic studies indicate that BMIPP can identify previous ischemia as reduced tracer uptake.

METHODS

This study prospectively enrolled 111 consecutive patients with acute chest pain without myocardial infarction. Tetrofosmin SPECT was performed at rest within 24 h after the last episode of chest pain. Coronary angiography and BMIPP SPECT were also performed on the following day.

RESULTS

Sixty-four of the 87 patients with coronary stenosis or spasm showed BMIPP abnormalities corresponding to the areas of coronary abnormalities (sensitivity 74%), whereas only 33 of them showed perfusion abnormalities (sensitivity 38%) (p < 0.001). Of the 24 patients without coronary stenosis or spasm, 22 showed normal BMIPP SPECT (specificity 92%), and 23 showed normal tetrofosmin SPECT (sensitivity 96%). Coronary stenosis was more often seen in the group with abnormal tetrofosmin/abnormal BMIPP (82%) and with normal tetrofosmin/abnormal BMIPP (69%) than in the group with normal tetrofosmin/normal BMIPP (36%) (p < 0.05). Coronary spasm was observed more often in the group with abnormal tetrofosmin/abnormal BMIPP (83%) and with normal tetrofosmin/abnormal BMIPP (90%) than in the group with normal tetrofosmin/normal BMIPP (27%) (p < 0.05). The extent and severity scores of tetrofosmin and BMIPP in the patients with organic stenosis were significantly higher than those of patients with no organic stenosis or spasm (p < 0.0001).

CONCLUSIONS

These data indicate that BMIPP SPECT may specifically identify previous ischemic lesions due to coronary stenosis or spasm in patients with acute chest pain.     

A comparison of systematic stenting and conventional balloon angioplasty during primary percutaneous transluminal coronary angioplasty for acute myocardial infarction

OBJECTIVES

In a multicenter, randomized trial, systematic stenting using the Wiktor stent was compared to conventional balloon angioplasty with provisional stenting for the treatment of acute myocardial infarction (AMI).

BACKGROUND

Primary angioplasty in AMI is limited by in-hospital recurrent ischemia and a high restenosis rate.

METHODS

A total of 211 patients with AMI <12 h from symptom onset, with an occluded native coronary artery, were randomly assigned to systematic stenting (n = 101) or balloon angioplasty (n = 110). The primary end point was the binary six-month restenosis rate determined by core laboratory quantitative angiographic analysis.

RESULTS

Angiographic success (Thrombolysis in Myocardial Infarction [TIMI] flow grade 3 and residual diameter stenosis <50%) was achieved in 86% of the patients in the stent group and in 82.7% of those in the balloon angioplasty group (p = 0.5). Compared with the 3% cross-over in the stent group, cross-over to stenting was required in 36.4% of patients in the balloon angioplasty group (p = 0.0001). Six-month binary restenosis (≥50% residual stenosis) rates were 25.3% in the stent group and 39.6% in the balloon angioplasty group (p = 0.04). At six months, the event-free survival rates were 81.2% in the stent group and 72.7% in the balloon angioplasty group (p = 0.14), and the repeat revascularization rates were 16.8% and 26.4%, respectively (p = 0.1). At one year, the event-free survival rates were 80.2% in the stent group and 71.8% in the balloon angioplasty group (p = 0.16), and the repeat revascularization rates were 17.8% and 28.2%, respectively (p = 0.1).

CONCLUSIONS

In the setting of primary angioplasty for AMI, as compared with a strategy of conventional balloon angioplasty, systematic stenting using the Wiktor stent results in lower rates of angiographic restenosis.     

Different Mechanisms of Ischemic Adaptation to Repeated Coronary Occlusion in Patients With and Without Recruitable Collateral Circulation

Objectives. The aim of this study was to investigate the interaction between ischemic preconditioning (IP) and collateral recruitment (CR) during ischemic adaptation in patients.

Background. The mechanism of ischemic adaptation still remains controversial in humans.

Methods. The clinical, electrocardiographic, hemodynamic and echocardiographic responses to three 150-s occlusions of the left anterior descending coronary artery were assessed in relation to CR in 18 patients with effort angina undergoing elective percutaneous transluminal coronary angioplasty.

Results. During the first occlusion, recruitable collateral circulation (RCC) to the occluded myocardium was detected by myocardial contrast echocardiography in 6 patients (Group C) and was not seen in 12 (Group N). In Group N, all patients manifested signs of severe ischemia during each inflation. However, their symptoms and ST segment shift significantly decreased from the first to the third occlusions, suggesting the occurrence of IP. The elevation of mean pulmonary artery pressure and deterioration of anterior wall motion were comparable between the first and the third occlusions in Group N. In contrast, myocardial ischemia was significantly less marked during occlusion in Group C than in Group N, and no preconditioning effect was observed. The extent of RCC did not differ between the first and the third occlusions in each group.

Conclusions. Both IP and CR may play independent roles in ischemic adaptation in humans. With RCC, myocardial ischemia was greatly reduced. Without RCC, preconditioning clinically and electrocardiographically lessened myocardial ischemia but failed to preserve left ventricular function.     

Temporal trends in the treatment of over 1.5 million patients with myocardial infarction in the US from 1990 through 1999: the National Registry of Myocardial Infarction 1, 2 and 3

OBJECTIVES

We sought to determine trends in the treatment of myocardial infarction from 1990 through 1999 in the U.S. and to relate these trends to current guidelines.

BACKGROUND

Limited data are available to show how recent clinical trials and clinical guidelines have impacted treatment of myocardial infarction.

METHODS

Temporal trends in myocardial infarction treatment and outcome were assessed by using data from 1,514,292 patients in the National Registry of Myocardial Infarction (NRMI) 1, 2 and 3 from 1990 through 1999.

Results

During this interval, the use of intravenous thrombolytic therapy declined from 34.3% to 20.8%, but the use of primary angioplasty increased from 2.4% to 7.3% (both P = 0.0001). The median “door-to-drug” time among thrombolytic therapy recipients fell from 61.8 to 37.8 min (p = 0.0001), primarily owing to shorter “door-to-data” and “data-to-decision” times. The prevalence of non–Q wave infarctions increased from 45% in 1994 to 63% in 1999 (p = 0.0001). From 1994 through 1999, there was increased usage of beta-blockers, aspirin and angiotensin-converting inhibitors, both during the first 24 h after admission and on hospital discharge (all P = 0.0001). Between 1990 and 1999, the median duration of hospital stay fell from 8.3 to 4.3 days, and hospital mortality declined from 11.2% to 9.4% (both P = 0.0001).

CONCLUSIONS

The NRMI data from 1990 through 1999 demonstrate that the recommendations of recent clinical trials and published guidelines are being implemented, resulting in more rapid administration of intravenous thrombolytic therapy, increasing use of primary angioplasty and more frequent use of adjunctive therapies known to reduce mortality, and may be contributing to the higher prevalence of non–Q wave infarctions, shorter hospital stays and lower hospital mortality.     

Pre-operative CT coronary angiography in patients with mitral valve prolapse referred for surgical repair: Comparison of accuracy,radiation dose and cost versus invasive coronary angiography

Background

The aims of this study are to evaluate the accuracy of low dose multidetector computed tomography coronary angiography (MDCT) versus invasive coronary angiography (ICA) in ruling out CAD in patients with mitral valve prolapse and severe mitral regurgitation (MVP) before cardiac surgery and to compare the overall effective radiation dose (ED) and cost of a diagnostic approach in which conventional ICA should be performed only in patients with significant CAD as detected by MDCT.

Methods

Eighty patients with MVP and without history of CAD were randomized to MDCT (Group 1) or ICA (Group 2) to rule out CAD before surgery. However, ICA was also performed as gold standard reference in Group 1 to test the diagnostic accuracy of MDCT. A diagnostic work-up A in whom all patients underwent low-dose MDCT as initial diagnostic test and those with positive findings were referred for ICA was compared with work-up B in which all patients were referred for ICA according to the standard of care in terms of ED and cost.

Results

The two groups were homogeneous in terms of gender, age and body mass index. The overall feasibility and accuracy in a patient-based model were 99% and 93%, respectively. The overall ED and costs were significantly lower in diagnostic work-up A compared to diagnostic work-up B.

Conclusions

The accuracy of low dose MDCT for ruling out the presence of significant CAD in patients undergoing elective valve surgery for mitral valve prolapse is excellent with a reduction of overall radiation dose exposure and costs.     

The role of cardiovascular magnetic resonance in patients with acute coronary syndromes

Cardiovascular magnetic resonance (CMR) imaging is a recognized technique for characterization of myocardial tissue in stable ischemic heart disease. In addition, CMR is emerging as a noninvasive imaging tool that can provide supporting information to guide treatment in acute coronary syndromes (ACSs). The advantages of using CMR acutely could potentially include triage/differential diagnosis in patients presenting with chest pain and troponin rise but without diagnostic electrocardiogram changes, assessment of severity of myocardial injury (irreversible vs reversible damage) in patients with ST-elevation myocardial infarction and non–ST-elevation myocardial infarction, and risk stratification and assessment of prognosis in patients with ACS. This review evaluates a potential clinical role of CMR in the acute setting, highlighting its advantages and limitations. This critical approach emphasizes areas of uncertainty and ongoing controversies but aims to equip the reader to evaluate the potential clinical application and the practicalities of CMR in patients presenting with ACS.     

Reperfusion strategies in acute ST-segment elevation myocardial infarction: a comprehensive review of contemporary management options

There are an estimated 500,000 ST-segment elevation myocardial infarction (STEMI) events in the U.S. annually. Despite improvements in care, up to one-third of patients presenting with STEMI within 12 h of symptom onset still receive no reperfusion therapy acutely. Clinical studies indicate that speed of reperfusion after infarct onset may be more important than whether pharmacologic or mechanical intervention is used. Primary percutaneous coronary intervention (PCI), when performed rapidly at high-volume centers, generally has superior efficacy to fibrinolysis, although fibrinolysis may be more suitable for many patients as an initial reperfusion strategy. Because up to 70% of STEMI patients present to hospitals without on-site PCI facilities, and prolonged door-to-balloon times due to inevitable transport delays commonly limit the benefit of PCI, the continued role and importance of the prompt, early use of fibrinolytic therapy may be underappreciated. Logistical complexities such as triage or transportation delays must be considered when a reperfusion strategy is selected, because prompt fibrinolysis may achieve greater benefit, especially if the fibrinolytic-to-PCI time delay associated with transfer exceeds approximately 1 h. Selection of a fibrinolytic requires consideration of several factors, including ease of dosing and combination with adjunctive therapies. Careful attention to these variables is critical to ensuring safe and rapid reperfusion, particularly in the prehospital setting. The emerging modality of pharmacoinvasive therapy, although controversial, seeks to combine the benefits of mechanical and pharmacologic reperfusion. Results from ongoing clinical trials will provide guidance regarding the utility of this strategy.     

Late gadolinium enhancement CMR predicts adverse cardiovascular outcomes and mortality in patients with coronary artery disease: systematic review and meta-analysis

Cardiovascular magnetic resonance (CMR) has a recognized role in diagnosing and monitoring coronary artery disease (CAD). Multiple studies have shown that CMR can predict adverse outcomes. We reviewed contemporary available literature to establish the role of CMR with late gadolinium enhancement (LGE) in predicting mortality and major adverse cardiac events (MACEs) in patients with CAD. Meta-analysis of available prospective studies showed that the presence of LGE increases the hazards of death by more than 4 times and of MACE by almost 4 times. The size of LGE (per gram or percent) increases the hazards of death and MACE by 4% and 5%, respectively. The presence and size of LGE predict mortality and MACE in CAD. Various parameters derived from LGE images enhance the predictive value. Large randomized controlled trials are needed to establish the actual value of LGE and other derived parameters in the wider population.     

Assessment of myocardial ischemia with cardiovascular magnetic resonance

Assessment of myocardial ischemia in symptomatic patients remains a common and challenging clinical situation faced by physicians. Risk stratification by presence of ischemia provides important utility for both prognostic assessment and management. Unfortunately, current noninvasive modalities possess numerous limitations and have limited prognostic capacity. More recently, ischemia assessment by cardiovascular magnetic resonance (CMR) has been shown to be a safe, available, and potentially cost-effective alternative with both high diagnostic and prognostic accuracy. Cardiovascular magnetic resonance has numerous advantages over other noninvasive methods, including high temporal and spatial resolution, relatively few contraindications, and absence of ionizing radiation. Furthermore, studies assessing the clinical utility and cost effectiveness of CMR in the short-term setting for patients without evidence of an acute myocardial infarction have also demonstrated favorable results. This review will cover techniques of ischemia assessment with CMR by both stress-induced wall motion abnormalities as well as myocardial perfusion imaging. The diagnostic and prognostic performance studies will also be reviewed, and the use of CMR for ischemia assessment will be compared with other commonly used noninvasive modalities.     

Epicardial adipose tissue volume as a marker of coronary artery disease severity in patients with diabetes independent of coronary artery calcium: Findings from the CTRAD study

AimsThe association between epicardial adipose tissue (EAT) volume and coronary artery disease (CAD) severity was evaluated, independent of traditional risk factors and coronary artery calcium (CAC) scores, in patients with diabetes type 2 (DM-2) using cardiac computed tomography angiography (CTA).MethodsA multivariate analysis was utilized to assess for an independent association after calculating EAT volume, CAD severity, and calcium scores in 92 patients with DM-II from the CTRAD study. We graded CAD severity as none (normal coronaries), mild-moderate (<70% stenosis), and severe (70% or greater stenosis).ResultsA total of 39 (42.3%) asymptomatic patients with diabetes did not have CAD; 30.4% had mild/moderate CAD; and 27.1% had severe CAD. Mean EAT volume was highest in patients with severe CAD (143.14 cm³) as compared to mild/moderate CAD (112.7 cm³), and no CAD (107.5 cm³) (p = 0.003). After adjustment of clinical risk factors, notably, CAC score, multivariate regression analysis showed EAT volume was an independent predictor of CAD severity in this sample (odds ratio 11.2, 95% confidence interval 1.7–73.8, p = 0.01).ConclusionsIncreasing EAT volume in asymptomatic patients with DM-II is associated with presence of severe CAD, independent of BMI and CAC, as well as traditional risk factors.