Dobutamine stress myocardial perfusion imaging in coronary artery disease.

The accurate noninvasive diagnosis and functional evaluation of coronary artery disease is an important step in selecting the appropriate management strategy. Dobutamine stress myocardial perfusion imaging is an alternative to exercise in patients with limited exercise capacity. In many centers, the test is performed on patients who have a contraindication for vasodilator stress testing. Recent studies have shown hyperemia induced by the standard dobutamine-atropine stress test is not less than hyperemia induced by dipyridamole. The feasibility of the test is 90% and is often higher in patients without beta-blocker therapy. The safety of the test has been well studied and was also demonstrated in specific patients groups, such as patients with left ventricular dysfunction, the elderly, and heart transplant recipients. The diagnostic accuracy has been demonstrated in patients with and without myocardial infarction and in specific groups such as those with hypertension, left ventricular hypertrophy, and heart transplant recipients and after revascularization. The technique has a high sensitivity for prediction of functional recovery in patients with myocardial dysfunction referred for revascularization. The presence and severity of myocardial perfusion abnormalities assessed by this method are powerful predictors of cardiac events, incremental to clinical data. This article describes the methodology, safety, feasibility, diagnostic accuracy, and prognostic value of dobutamine stress myocardial perfusion imaging in patients with known or suspected coronary artery disease, with additional considerations for the application of the test in specific patient groups.     

The clinical importance of electrocardiographic changes during pharmacologic stress testing with radionuclide myocardial perfusion imaging

Conclusion  Radionuclide MPI has become a reliable tool for the detection and surveillance of suspected or known CAD, regardless of whether it is used in combination with exercise or pharmacologic stress agents. The presence of an abnormal electrocardiogram, especially during a pharmacologic stress test, may indicate an elevated risk of multivessel CAD and higher annualized cardiac event rates. Therefore the presence of ischemic ECG changes should prompt further evaluation, even in the presence of normal MPI.     

Prognostic estimation of coronary artery disease risk with resting perfusion abnormalities and stress ischemia on myocardial perfusion SPECT

Background. The extent and severity of stress ischemia are strong predictors of coronary artery disease (CAD) events. Prognosis associated with myocardial perfusion single photon emission computed tomography (MPS) abnormalities on the resting scan as it relates to stress ischemia has been incompletely described. Methods and Results. The Myoview Prognosis Registry was a prospective consecutive series of 7849 outpatients enrolled from 5 geographically diverse centers. Patients were followed up for the occurrence of CAD events (nonfatal myocardial infarction [MI] or death related to MI, heart failure, or sudden cardiac death). Time to CAD event (n=545) was estimated by use of univariable and multivariable Cox proportional hazards models (risk adjusted by symptoms, risk factors, and comorbid conditions). For patients with no resting defects, overall CAD event rates were 1.2%, 8%, and 10% for patients with 0% ischemic myocardium, 1% to 4.9% ischemic myocardium, and 5% ischemic myocardium or greater, respectively (P<.0001). As the percent myocardium with resting defects worsened, overall CAD event rates increased, such that for patients with 10% or more of the rest myocardium with perfusion defects, cardiovascular death or MI rates ranged from 7% to 44% (P<.0001). In a model including both the percent of the myocardium with resting defects and the percent ischemia, both were highly predictive of CAD events (P<.0001). For every 1% increase in ischemic myocardium, there was a 7% increased risk of CAD events (P<.0001). A 3% increase in risk of CAD events was observed for patients with every 1% of the myocardium with resting defects (P<.0001). Conclusions. The estimation of CAD risk may be optimally estimated by use of a combination of resting MPS, reflecting a patient’s burden of disease, and MPS with provocative ischemia. Partial unrestricted grant support for this project was provided by GE Healthcare.     

Intracoronary myocardial perfusion imaging: patterns in patients with coronary artery disease

Myocardial imaging following the intracoronary injection of radiolabeled particles is used to identify transmural scars in patients being evaluated for coronary atherosclerosis. Selective imaging of the microcirculation derived from each major coronary vessel is accomplished using a dual radionuclide technique. This report illustrates the various normal and abnormal imaging patterns encountered in patients with coronary artery disease. The regional myocardial nomenclature proposed by the American Heart Association Council on Cardiovascular Surgery is used. Correlation of the nuclear study with the contrast arteriogram and ventriculogram is essential for identifying both transmural scars and regions of collateral circulation. The procedure is safe and can be performed during routine coronary angiography.     

Prognostic value of vasodilator response using rubidium-82 positron emission tomography myocardial perfusion imaging in patients with coronary artery disease

Background

Prognostic value of positron emission tomography (PET) myocardial perfusion imaging (MPI) is well established. There is paucity of data on how the prognostic value of PET relates to the hemodynamic response to vasodilator stress. We hypothesize that inadequate hemodynamic response will affect the prognostic value of PET MPI.

Methods and results

Using a multicenter rubidium (Rb)-82 PET registry, 3406 patients who underwent a clinically indicated rest/stress PET MPI with a vasodilator agent were analyzed. Patients were categorized as, “responders” [increase in heart rate?≥?10 beats per minute (bpm) and decrease in systolic blood pressure (SBP) ≥10 mmHg], “partial responders” (either a change in HR or SBP), and “non-responders” (no change in HR or SBP). Primary outcome was all-cause death (ACD), and secondary outcome was cardiac death (CD). Ischemic burden was measured using summed stress score (SSS) and % left ventricular (LV) ischemia. After a median follow-up of 1.68 years (interquartile range?=?1.17- 2.55), there were 7.9% (n?=?270) ACD and 2.6% (n?=?54) CD. Responders with a normal PET MPI had an annualized event rate (AER) of 1.22% (SSS of 0–3) and 1.58% (% LV ischemia?=?0). Partial and non-responders had higher AER with worsening levels of ischemic burden. In the presence of severe SSS ≥12 and LV ischemia of ≥10%, partial responders had an AER of 10.79% and 10.36%, compared to non-responders with an AER of 19.4% and 12.43%, respectively. Patient classification was improved when SSS was added to a model containing clinical variables (NRI: 42%, p?<?0.001) and responder category was added (NRI: 61%,

Conclusion

Hemodynamic response during a vasodilator Rb-82 PET MPI is predictive of ACD. Partial and non-responders may require additional risk stratification leading to altered patient management.

     

Adenosine triphosphate stress myocardial perfusion imaging for risk stratification of patients aged 70 years and older with suspected coronary artery disease

Objective

We investigated the cardiac risk stratification value of adenosine triphosphate stress myocardial perfusion imaging (ATP-MPI) in patients aged 70 years and older with suspected coronary artery disease (CAD).

Methods

We identified a series of 415 consecutive patients aged 70 years and older with suspected CAD, who had undergone ATP-MPI with ^99mTc-MIBI. The presence of a fixed and/or reversible perfusion defect was considered as an abnormal MPI. Follow-up was available in 399 patients (96.1%) over 3.45 ± 1.71 years after excluding 16 patients who underwent early coronary revascularization <60 days after MPI. The major adverse cardiac events (MACE), including cardiac death, nonfatal infarction, and late coronary revascularization, were recorded.

Results

One hundred twenty-five (31.3%) patients had abnormal MPI and the remaining had normal MPI. A multivariable analysis using Cox regression demonstrated that abnormal MPI was independently associated with MACE (hazard ratio 19.50 and 95% confidence interval 5.91-64.31, P value .000). The patients with SSS > 8 had significantly higher cumulative MACE rate than patients with SSS ≤ 8 had (37.8% vs 5.2%, respectively, P < .001). The Kaplan-Meier cumulative MACE-free survival in patients with abnormal MPI (57.0%) was significantly lower than that in patients with normal MPI (89.6%), P < .0001. Among patients with SSS > 8, the Kaplan-Meier cumulative MACE-free survival were 36.9% in patients ≥80 years old and 49.5% in patients 70-79 years old, respectively, P < .05. However, among patients with SSS ≤ 8, there was no difference between the Kaplan-Meier cumulative MACE-free survivals of these two age groups.

Conclusions

ATP-MPI data are useful for the prediction of major adverse cardiac events in patients aged 70 years and older with suspected CAD.

     

Prevalence,location, and extent of significant coronary artery disease in patients with normal myocardial perfusion imaging

Background

False-negative myocardial perfusion imaging (MPI) can by due to left main (LM) or three-vessel disease causing “balanced ischemia”. However, so far prevalence of LM or three-vessel-disease in patients with normal MPI is unclear. We assessed prevalence, location, and extent of significant coronary artery disease (CAD) in patients with normal MPI.

Methods

Between 2006 and 2010, 256 patients with normal MPI who had invasive angiography because of persisting or worsening of the same initial symptoms were studied. Significant CAD was defined as stenosis > 70% or LM > 50%.

Results

A total of 93 patients (36%) had significant CAD. Significant CAD was observed more frequently in males, higher age and those with typical angina complaints. Significant LM disease was present in 7%, three-vessel disease in 10%, two-vessel disease in 22%, and single vessel disease (not left main) in 61%. In those with single vessel disease, the location was the LAD in 40%, the RCA in 30%, and the LCX in 30%.

Conclusions

In selected patients with normal MPI, one-third had significant CAD. The majority of these patients had single vessel disease (not left main). LM or three vessel disease, causing “balanced ischemia”, is a less common cause of false-negative MPI.     

The prognostic value of non-perfusion variables obtained during vasodilator stress myocardial perfusion imaging

Myocardial perfusion imaging (MPI) is an established diagnostic test that provides useful prognostic data in patients with known or suspected coronary artery disease. In more than half of the patients referred for stress testing, vasodilator stress is used in lieu of exercise. Unlike exercise, vasodilator stress does not provide information on exercise and functional capacity, heart rate recovery, and chronotropy, and ECG changes are less frequent. These non-perfusion data provide important prognostic and patient management information. Further, event rates in patients undergoing vasodilator MPI are higher than in those undergoing exercise MPI and even in those with normal images probably due to higher pretest risk. However, there are a number of non-perfusion variables that are obtained during vasodilator stress testing, which have prognostic relevance but their use has not been well emphasized. The purpose of this review is to summarize the prognostic values of these non-perfusion data obtained during vasodilator MPI.     

Computed tomography coronary angiography accuracy in women and men at low to intermediate risk of coronary artery disease

Objectives

To investigate the diagnostic accuracy of CT coronary angiography (CTCA) in women at low to intermediate pre-test probability of coronary artery disease (CAD) compared with men.

Methods

In this retrospective study we included symptomatic patients with low to intermediate risk who underwent both invasive coronary angiography and CTCA. Exclusion criteria were previous revascularisation or myocardial infarction. The pre-test probability of CAD was estimated using the Duke risk score. Thresholds of less than 30?% and 30–90?% were used for determining low and intermediate risk, respectively. The diagnostic accuracy of CTCA in detecting obstructive CAD (≥50?% lumen diameter narrowing) was calculated on patient level. P?<?0.05 was considered significant.

Results

A total of 570 patients (46?% women [262/570]) were included and stratified as low (women 73?% [80/109]) and intermediate risk (women 39?% [182/461]). Sensitivity, specificity, PPV and NPV were not significantly different in and between women and men at low and intermediate risk. For women vs. men at low risk they were 97?% vs. 100?%, 79?% vs. 90?%, 80?% vs. 80?% and 97?% vs. 100?%, respectively. For intermediate risk they were 99?% vs. 99?%, 72?% vs. 83?%, 88?% vs. 93?% and 98?% vs. 99?%, respectively.

Conclusion

CTCA has similar diagnostic accuracy in women and men at low and intermediate risk.

Key Points

? Coronary artery disease (CAD) is increasingly investigated by computed tomography angiography (CTCA). ? CAD detection or exclusion by CTCA is not different between sexes. ? CTCA diagnostic accuracy was similar between low and intermediate risk sex-specific-groups. ? CTCA rarely misses obstructive CAD in low–intermediate risk women and men. ? CAD yield by invasive coronary angiography after positive CTCA is similar between sex-risk-specific groups.     

冠状动脉CTA对于中低度冠心病风险男性和女性病人的准确性

目的比较女性与男性低中度冠心病风险者中冠状动脉CT血管成像的诊断准确性。方法此回顾性研究包括有低中度冠心病风险的有症状病人,进行了介入冠状动脉造影和冠状动脉CTA检查。排除标准为既往曾行血管再通治疗或心肌梗死的病人。采用Duke风险评分初步评估冠心病的可能性。分别以小于30%和30%～90%为低度和中度风险。计算冠状动脉CTA在病人水平上显示阻塞性冠心病(管腔狭窄≥50%)的诊断准确性。以P<0.05有统计学意义。结果共有570例病人(46%为女性,262/570),分为低度(73%为女性,80/109)和中度(39%为女性,182/461)风险。无论男性和女性,低度和中度风险组,其间诊断的敏感度、特异度、阳性和阴性预测值的差异均没有统计学意义。在低风险组,对于女性和男性分别为97%和100%,79%和90%,80%和80%,97%和100%;而在中度风险组,对于女性和男性分别是99%和99%,72%和83%,88%和93%,98%和99%。结论冠状动脉CTA对于中低度冠心病风险的男性和女性有相似的诊断准确性。     

慢性稳定型冠心病的核素心肌灌注显像临床应用进展

多项临床试验证明,核素心肌灌注显像在冠心病诊断、危险度分层、预后判断、病人处理方案等方面具有突出的作用和优越的价值。在ACC/AHA(美国心脏病学院/美国心脏学会)有关冠心病和核心脏病学指南中,心肌灌注显像的上述作用得到了充分肯定。合理应用该项技术可以提高对冠心病诊断、处理的整体水平,并使有限的医疗资源得到更合理利用,这在我国目前显得十分迫切和需要。     

Simultaneous assessment of myocardial perfusion and function during mental stress in patients with chronic coronary artery disease

BACKGROUND: Mental stress (MS) is an important provocateur of myocardial ischemia in many patients with chronic coronary artery disease. The majority of laboratory assessments of ischemia in response to MS have included measurements of either myocardial perfusion or function alone. We performed this study to determine the relationship between alterations in perfusion and ventricular function during MS.Methods and results Twenty-eight patients with reversible perfusion defects on exercise or pharmacologic stress myocardial perfusion imaging (MPI) underwent simultaneous technetium 99m sestamibi single photon emission computed tomography (SPECT) MPI and transthoracic echocardiography at rest and during MS according to a mental arithmetic protocol. In all cases the MS study was performed within 4 weeks of the initial exercise or pharmacologic MPI that demonstrated ischemia. SPECT studies were analyzed visually with the use of a 13-segment model and quantitatively by semiautomated circumferential profile analysis. Echocardiograms were graded on a segmental model for regional wall motion on a 4-point scale. Of 28 patients, 18 (64%) had perfusion defects and/or left ventricular dysfunction develop during MS: 9 (32%) had myocardial perfusion defects develop, 6 (21%) had regional or global left ventricular dysfunction develop, and 3 (11%) had both perfusion defects and left ventricular dysfunction develop. The overall concordance between perfusion and function criteria for ischemia during MS was only 46%. Among 9 patients with MS-induced left ventricular dysfunction, 5 had new regional wall motion abnormalities and 4 had a global decrement in function. In patients with MS-induced ischemia by SPECT, the number of reversible perfusion defects was similar during both MS and exercise/pharmacologic stress (2.8 +/- 2.0 vs 3.5 +/- 1.8, P =.41). Hemodynamic changes during MS were similar whether patients were divided on the basis of perfusion defects or left ventricular dysfunction during MS. CONCLUSIONS: These data indicate the feasibility of simultaneous assessment of perfusion and function responses during MS. Flow and function responses to MS are frequently not concordant. These data suggest that MS-induced changes in perfusion may represent a different phenomenon than MS-induced changes in left ventricular function (either globally or regionally).     

Stress myocardial perfusion imaging versus echocardiography for the diagnosis and risk stratification of patients with known or suspected coronary artery disease

Stress perfusion imaging and stress echocardiography (ECHO) are both very useful for assessment of diagnosis and risk stratification of patients with coronary artery disease (CAD). Both techniques have been well validated during exercise and inotropic stress, but coronary vasodilation stress is better used in combination with perfusion imaging. The overall sensitivity for detection of CAD is slightly higher by single photon emission computed tomography (SPECT) than by two-dimensional (2D) ECHO during all stress modalities, whereas the specificity is slightly higher by ECHO, although the differences in general are not statistically significant. SPECT, however, appears to be superior to ECHO in the diagnosis of isolated circumflex stenosis, as well as for the correct identification of multivessel CAD. A substantially greater amount of information is available regarding risk stratification with SPECT than with 2D ECHO. Although the data suggest that both techniques are very useful for risk stratification of patients with stable CAD, after myocardial infarction, and for preoperative risk stratification, the risk for cardiac events is lower in the presence of a normal stress SPECT study than of a normal stress ECHO.