Does risk for major adverse cardiac events in patients undergoing vasodilator stress with adjunctive exercise differ from patients undergoing either standard exercise or vasodilator stress with myocardial perfusion imaging?

Comparative predictors of mortality among patients referred for stress single-photon emission computed tomography versus positron emission tomography myocardial perfusion imaging

BACKGROUND

There is currently little information regarding the usage and comparative predictors of mortality among patients referred for single-photon emission computed tomography (SPECT) versus positron emission tomography (PET) myocardial perfusion imaging (MPI) within multimodality imaging laboratories.

METHODS

We compared the clinical characteristics and mortality outcomes among 15,718 patients referred for SPECT-MPI and 6202 patients referred for PET-MPI between 2008 and 2017.

RESULTS

Approximately two-thirds of MPI studies were performed using SPECT-MPI. The PET-MPI group was substantially older and included more patients with known coronary artery disease (CAD), hypertension, diabetes, and myocardial ischemia. The annualized mortality rate was also higher in the PET-MPI group, and this difference persisted after propensity matching 3615 SPECT-MPI and 3615 PET-MPI patients to have similar clinical profiles. Among the SPECT-MPI patients, the most potent predictor of mortality was exercise ability and performance, including consideration of patients' mode of stress testing and exercise duration. Among the PET-MPI patients, myocardial flow reserve (MFR) was the most potent predictor of mortality.

CONCLUSIONS

In our real-world setting, PET-MPI was more commonly employed among older patients with more cardiac risk factors than SPECT-MPI patients. The most potent predictors of mortality in our SPECT and PET-MPI groups were variables exclusive to each test: exercise ability/capacity for SPECT-MPI patients and MFR for PET-MPI patients.

Comparison of coronary artery calcium scores among patients referred for cardiac imaging tests

BACKGROUND

While coronary artery calcium (CAC) can now be evaluated by multiple imaging modalities, there is presently scant study regarding how CAC scores may vary among populations of varying clinical risk.

METHODS

We evaluated the distribution of CAC scores among three patient groups: 18,941 referred for CAC scanning, 5101 referred for diagnostic coronary CT angiography (CCTA), and 3307 referred for diagnostic positron emission tomography (PET) myocardial perfusion imaging (MPI). We assessed the relationship between CAC score and myocardial ischemia, obstructive coronary artery disease (CAD), and all-cause mortality across imaging modalities.

RESULTS

Within each age group, the frequency of CAC abnormalities were relatively similar across testing modalities, despite an annualized mortality rate which varied from 0.5%/year among CAC patients to 3.8%/year among PET-MPI patients (p < 0.001). Among CCTA and PET-MPI patients, a zero CAC score was common, occurring in ~70% of patients <50 years, ~40% of patients 50-59 years, and ~ 25% of patients 60-69 years. Among CCTA patients, zero CAC was associated with a normal coronary angiogram with high frequency, ranging from 92.2% among patients <50 years to 87.9% among patients ≥70 years. Among PET-MPI patients, zero CAC was associated with a very low frequency of inducible ischemia across all age groups, ranging from 1.5% among patients <50 years to 0.9% among patients ≥70 years.

CONCLUSIONS

In our study, relatively similar CAC scores were noted among patients varying markedly in mortality risk. Clinically, zero CAC scores predicted both a low likelihood of obstructive CAD and inducible myocardial ischemia in all age groups and were observed with high frequency across diagnostic testing modalities.

Cardiology and lifestyle medicine

Poor lifestyle habits, such as physical inactivity and poor diets, are highly prevalent within society and even more so among patients with chronic disease. The need to stem poor lifestyle habits has led to the development of a new field of Lifestyle Medicine, whose mission is to prevent, treat, and even reverse chronic diseases through lifestyle interventions. Three fields within Cardiology relate to this mission: Cardiac Rehabilitation, Preventive Cardiology, and Behavioral Cardiology. Each of these three fields have contributed substantially to the reduction of cardiovascular disease (CVD) morbidity and mortality. The historic contributions of these three cardiac fields are reviewed as well as the challenges each of these fields has faced in optimizing the application of lifestyle medicine practices. A shared agenda between Cardiology and the American College of Lifestyle Medicine could further the utilization of behavioral interventions. This review suggests seven steps that could be shared by these organizations and other medical societies. First, there is a need to develop and promulgate the assessment of lifestyle factors as "vital signs" during patient visits. Second, developing a strong partnership between the fields of Cardiology and Physiatry could improve important aspects of cardiac care, including a potential redesign of cardiac stress testing. Third, behavioral evaluations should be optimized at patients' entrée points into medical care since these may be considered "windows of opportunity". Fourth, there is a need to broaden cardiac rehabilitation into inexpensive programs and make this program eligible for patients with risk factors but no known CVD. Fifth, lifestyle medicine education should be integrated into the core competencies for relevant specialties. Sixth, there is a need for inter-societal advocacy to promote lifestyle medicine practices. Seventh, the well-being effects of healthy lifestyle behaviors, such as their impact on one's sense of vitality, should be emphasized.

Assessment of lifestyle-related risk factors enhances the effectiveness of cardiac stress testing

Cardiac stress tests have been widely utilized since the 1960s for the diagnostic and prognostic assessment of patients with suspected coronary artery disease (CAD). Clinical risk is primarily based on assessing the presence and magnitude of inducible myocardial ischemia. However, the primary factors driving mortality risk have changed over recent decades. Factors such as typical angina and inducible ischemia have decreased, whereas the percentage of patients with diabetes, obesity and hypertension have increased. There has also been a marked temporal increase in the percentage of patients who require pharmacologic testing due to inability to perform treadmill exercise at the time of cardiac stress testing and this need has emerged as the most potent predictor of mortality risk in contemporary stress test populations. However, the long-term clinical risk posed by the inability to perform exercise and concomitant CAD risk factors are rarely reflected in the assessment of patients' prognostic risk in cardiac stress test reports. In this review, we suggest that the clinical utility of present-day cardiac stress testing can be improved by developing a more comprehensive assessment that integrates and reports all factors which modulate patients' long-term clinical risk following stress testing. This should include assessment of patients' CAD risk factors, physical activity habits and mobility risks, identification of the reasons why patients could not exercise at the time of cardiac stress testing. In addition, the assessment of four core non-aerobic functional parameters should be considered among patients who cannot exercise: assessment of gait speed, handgrip strength, lower extremity strength, and standing balance.

Musculoskeletal exercise: Its role in promoting health and longevity

Resistance training (RT) is an often ignored but essential component of physical health.. The functioning of the musculoskeletal system declines with age, resulting in sarcopenia, loss of muscle strength and power, decrease in muscle flexibility and balance. Other pertinent age-related changes include decline in basal metabolic rate, increase in fat mass, and decrease in bone mineral density. Such primary aging can be accentuated by the concomitant presence of comorbid conditions, such as insulin resistance and diabetes, obesity, inflammatory conditions, and physical inactivity (PI). The latter is often promoted by the presence of musculoskeletal conditions, such as osteoarthritis, back pain, and osteoporosis, which are quite common in society. RT can diminish long-term joint stress, "resist" age-related physiological deterioration and improve health outcomes through its ability to increase muscle strength and mass, balance the distribution of forces within a joint, increase basal metabolic rate and bone density, reduce body fat and cardiac risk factors, enhance endothelial function, and promote cognitive function and psychological well-being. Accordingly, health providers should screen for PI, lack of RT, and mobility risks using short screening questions, and employ simple functional tests, when indicated, to evaluate patients for impairment in gait, muscle strength, flexibility, and balance. This review also provides general principles for initiating and conducting RT and provides general and specific examples of resistance training programs, which should be individualized for patients through the evaluation and guidance by appropriate health providers, physical therapists, and certified trainers.

The prevalence and predictors of inducible myocardial ischemia among patients referred for radionuclide stress testing

BACKGROUND

The frequency of inducible myocardial ischemia has declined in contemporary stress test cohorts, suggesting a need to re-evaluate its optimal use. To-date, however, a comprehensive analysis of the most potent predictors of myocardial ischemia among cardiac stress test patients has not been conducted.

METHODS

We assessed 27,615 patients referred for stress-rest SPECT myocardial perfusion imaging between January 1, 2004 and December 31, 2017. Chi-square analysis was used to ascertain the most potent predictors of ischemia.

RESULTS

Among our cohort, CAD status (presence/absence of known CAD), rest left ventricular ejection fraction (LVEF), and typical angina were the most potent predictors of ischemia. The frequency of ischemia was only 6.6% among patients with an LVEF > 55% but 38.1% for patients with LVEF < 45% (P < 0.001). The frequency of myocardial ischemia was fourfold higher among patients with known CAD vs no known CAD (28.0% vs 6.5%, P < 0.001) and approximately threefold higher among patients with typical angina vs patients with atypical symptoms (P < 0.001).

CONCLUSIONS

The frequency of myocardial ischemia varies markedly according to the common clinical parameters and is particularly high among patients with known CAD, low LVEF, and typical angina. These observations may be used to develop more cost-effective strategies for referring patients for cardiac stress testing.

Cardiac functional imaging

During the last 20 years, cardiac imaging has drastically evolved. Positron emission tomography (PET), fast three-dimensional (3D) imaging with the latest generations of echocardiography & multi-detector computed tomography (CT), stress perfusion assessed by magnetic resonance imaging (MRI), blood flow analysis using four-dimensional (4D) flow MRI, all these techniques offer new trends for optimal noninvasive functional cardiac imaging. Dynamic functional imaging is obtained by acquiring images of the heart at different phases of the cardiac cycle, allowing assessment of cardiac motion, function, and perfusion. Between CT and Cardiac MRI (CMR), CMR has the best temporal resolution, which is suitable for functional imaging while cardiac CT provides higher spatial resolution with isotropic data that have an identical resolution in the three dimensions of the space. The latest generations of CT scanners enable whole heart assessment in one beat, offering also an acceptable temporal resolution with the possibility to display the images in a dynamic mode. Another rapidly growing technique using functional and molecular imaging for the assessment of biological and metabolic pathways is the PET using radio-labeled tracers. Meanwhile, the oldest cardiac imaging tool with doppler ultrasound technology has never stopped evolving. Echocardiography today performs 3D imaging, stress perfusion, and myocardial strain assessment, with high temporal resolution. It still is the first line and more accessible exam for the patient. These different modalities are complementary and may be even combined into PET-CT or PET-MRI. The ability to combine the functional/molecular data with anatomical images may implement a new dimension to our diagnostic tools.

Mortality risk among patients undergoing exercise versus pharmacologic myocardial perfusion imaging: A propensity-based comparison

BACKGROUND

The increased risk associated with pharmacologic versus exercise testing is obscured by the higher prevalence of clinical risk factors among pharmacologic patients. Thus, we assessed comparative mortality in a large risk factor-matched group of exercise versus pharmacologic patients undergoing stress/rest SPECT myocardial perfusion imaging (MPI).

METHODS

39,179 patients undergoing stress/rest SPECT-MPI were followed for 13.3 ± 5.0 years for all-cause mortality (ACM). We applied propensity-matching to create pharmacologic and exercise groups with similar risk profiles.

RESULTS

In comparison to exercise patients, pharmacologic patients had an increased risk-adjusted hazard ratio for ACM for each level of ischemia: increased by 3.8-fold (95%CI 3.5-4.1) among nonischemic patients, 2.5-fold (95%CI 2.0-3.2) among mildly ischemic patients, and 2.6-fold (95%CI 2.1-3.3) among moderate/severe ischemic patients. Similar findings were observed among a propensity-matched cohort of 10,113 exercise and 10,113 pharmacologic patients as well as in an additional cohort that also excluded patients with noncardiac co-morbidities.

CONCLUSIONS

Patients requiring pharmacologic stress testing manifest substantially heightened clinical risk at each level of myocardial ischemia and even when myocardial ischemia is absent. These findings suggest the need to study the pathophysiological drivers of increased risk in association with pharmacologic testing and to convey this risk in clinical reports.

P-Wave Terminal Force V1 Is Associated with Left Ventricular Diastolic Function in Patients with No Significant Perfusion Abnormality

P-wave terminal force in lead V1 (PTFV1) is a marker of increased left atrial (LA) overload. Whether PTFV1 is associated with left ventricular (LV) diastolic function remains undetermined. We tested the hypothesis that PTFV1 is associated with LV diastolic parameters derived from gated myocardial perfusion single-photon emission computed tomography (SPECT) in patients with no significant perfusion abnormalities.The study population included 158 patients with preserved ejection fraction and no significant perfusion abnormalities. The amplitude and duration of the P-wave negative phase in lead V1 were measured using an electrocardiogram, and PTFV1 was calculated. The peak filling rate (PFR) and one-third mean filling rate (1/3 MFR) were obtained as LV diastolic parameters using gated SPECT.PTFV1 showed a weak correlation with the LA volume index (r = 0.31; P < 0.001). Significant associations were observed between PTFV1 and PFR (r = -0.27; P < 0.001) and 1/3 MFR (r = -0.26; P = 0.001). A multivariate linear regression analysis showed that age (β = -0.26; P < 0.001), LV end-diastolic volume index (β = -0.27; P = 0.001), and PTFV1 (β = -0.15; P = 0.036) were significant factors associated with PFR. Moreover, male gender (β = -0.16; P = 0.041), LV mass index (β = -0.17; P = 0.046), and PTFV1 (β = -0.17; P = 0.022) were significant factors associated with the 1/3 MFR.PTFV1 is associated with LV diastolic function, as derived from gated SPECT in patients with no significant perfusion abnormalities.

The Monocyte to High-Density Lipoprotein Cholesterol Ratio Is Associated with Left Ventricular Diastolic Function in Patients with No Significant Perfusion Abnormality

The monocyte to high-density lipoprotein cholesterol (HDL-C) ratio has been considered to be a prognostic marker. Whether this ratio is associated with left ventricular (LV) diastolic function remains undetermined. We tested the hypothesis that the monocyte to HDL-C ratio is associated with LV diastolic parameters derived from gated myocardial perfusion single-photon emission computed tomography (SPECT) in patients with no significant perfusion abnormality.The study population included 196 patients with no significant perfusion abnormalities and preserved ejection fraction. The peak filling rate (PFR) and one-third mean filling rate (1/3 MFR) were obtained as LV diastolic parameters using gated SPECT. Monocyte counts and plasma HDL-C levels were also examined.Significant associations were observed between the monocyte to HDL-C ratio and PFR (r = -0.20; P = 0.005) and 1/3 MFR (r = -0.19; P = 0.009). Multivariate linear regression analysis was performed to determine factors associated with LV diastolic parameters. Age (β = -0.27; P < 0.001), LV end-diastolic volume (β = -0.19; P = 0.034), and monocyte to HDL-C ratio (β = -0.15; P = 0.027) were determined to be significantly associated with PFR. Moreover, age (β = -0.13; P = 0.007), LV mass index (β = -0.18; P = 0.037), and the monocyte to HDL-C ratio (β = -0.13; P = 0.045) were significantly associated with 1/3 MFR.These results demonstrated that the monocyte to HDL-C ratio is associated with LV diastolic function, as derived from gated SPECT in patients with no significant perfusion abnormality.

Aortic valve calcium is associated with left ventricular diastolic function in patients without evidence of ischaemic heart disease: assessment by gated single-photon emission computed tomography

BACKGROUND

Several studies have shown that aortic valve calcium (AVC) is associated with cardiovascular events. Furthermore, the extent of AVC is associated with adverse prognosis even in patients without significant aortic stenosis. We investigated the relationship between AVC and left ventricular (LV) diastolic parameters determined by gated single-photon emission computed tomography (SPECT) in patients with no evidence of ischaemic heart disease.

METHODS

This study included 157 patients with no evidence of ischaemic heart disease who underwent both coronary computed tomography and gated SPECT. The AVC scores were calculated by the Agatston method, and peak filling rate (PFR) and one-third mean filling rate (1/3 MFR) were determined as LV diastolic parameters.

RESULTS

There were 93 (59%) and 64 (41%) patients with and without AVC, respectively, and the AVC scores ranged from 0 to 1251. There was no significant difference in LV end-diastolic volume (EDV) (60 ± 18 vs 62 ± 25 mL, p = 0.52) or LV ejection fraction (67% ± 10% vs 66% ± 8%, p = 0.60) between the two groups. Patients with AVC had lower PFR (2.2 ± 0.5 vs 2.4 ± 0.5 EDV/s, p = 0.002) and 1/3 MFR (1.3 ± 0.3 vs 1.5 ± 0.4 EDV/s, p = 0.003) than those without AVC. Multivariate linear regression analysis showed that ln(AVC score + 1) was significantly associated with PFR and 1/3 MFR.

CONCLUSION

In patients without evidence of ischaemic heart disease, the extent of AVC was inversely correlated with gated SPECT-derived parameters of LV diastolic function.

Changing Drivers of Mortality Among Patients Referred for Cardiac Stress Testing

Objective

To identify temporal shifts in coronary artery disease (CAD) risk factor profiles, clinical parameters, and corresponding mortality rates among patients referred for radionuclide stress testing over 22 years.

Patients and Methods

We assessed 39,750 patients with suspected CAD (“diagnostic” patients) and 10,982 patients with known CAD who underwent radionuclide stress testing between January 2, 1991, and December 31, 2012, and were followed up for at least 5 years (median, 12.7 years).

Results

Among both diagnostic patients and those with known CAD, there was a marked temporal decline in typical angina and myocardial ischemia. However, several risk factors for disease progressively increased, including diabetes, obesity, and hypertension. In addition, the need to perform pharmacological testing in lieu of exercise increased markedly between the first and fourth epochs among both diagnostic patients (from 26.5% [1634 of 6176] to 53.0% [5781 of 10,908]; P<.001) and patients with known CAD (from 31.1% [999 of 3213] to 75.5% [1405 of 1860]; P<.001). The net effect of these competing positive and negative risk factor trends was no change in the adjusted annualized rate of mortality over the temporal span in our study, ranging from 1.57% per year in 1991-1995 to 1.76% per year in 2006-2012 among diagnostic patients and from 2.46% per year to 2.75% per year during the same intervals among patients with known CAD.

Conclusion

Our findings suggest a marked contemporary shift in the drivers of all-cause mortality among patients undergoing cardiac stress tests away from such factors as typical angina and inducible myocardial ischemia, which are declining in prevalence, and toward such factors as diabetes and an inability to perform exercise, which are increasing in prevalence.

Association between coronary atherosclerotic burden and all-cause mortality among patients undergoing exercise versus pharmacologic stress-rest SPECT myocardial perfusion imaging

BACKGROUND AND AIMS

Patients with suspected coronary artery disease who undergo stress SPECT myocardial perfusion imaging (MPI) and require pharmacologic stress are at substantially increased mortality risk compared to those who can exercise. However, the mechanisms underlying this increased risk are not well delineated. To test whether increased atherosclerotic burden accounts for this increased risk, we assessed the association between coronary artery calcium (CAC) scores and mortality risk among patients undergoing exercise versus pharmacologic SPECT MPI.

METHODS

We assessed all-cause mortality in 2,151 patients, followed for 12.2 ± 3.4 years, after undergoing stress-rest SPECT-MPI and CAC scanning within 3 months of each other. Patients were divided according to their mode of stress testing (exercise or pharmacologic). We further employed propensity analysis to create a subgroup of exercise and pharmacologic subgroups with comparable age, symptoms, and coronary risk factors.

RESULTS

Despite greater age and worse clinical profiles, pharmacologic and exercise patients had similar CAC scores. However, the hazard ratio (95% CI) for mortality was substantially greater among pharmacologic patients: 2.39 (1.83-3.10). For each level of CAC abnormality, pharmacologic patients had >2-fold increased risk adjusted hazard ratio for all-mortality risk (p < 0.05 for each CAC level). Among propensity-matched exercise versus pharmacologic patients, the same findings were observed.

CONCLUSIONS

Among patients referred for stress-rest SPECT-MPI and CAC scoring, pharmacologic patients have substantially increased mortality risk compared to exercise patients, despite having comparable levels of coronary atherosclerosis.

Effects of aging on coronary flow reserve in patients with no evidence of myocardial perfusion abnormality

Coronary flow reserve (CFR) reflects the functional capacity of microcirculation to adapt to blood demand during increased cardiac work. We tested the hypothesis that aging had impacts on coronary flow velocities and CFR in patients with no evidence of myocardial perfusion abnormality on single photon emission computed tomography (SPECT). Seventy-six patients undergoing transthoracic Doppler echocardiography with no evidence of myocardial perfusion abnormality on SPECT were enrolled in this study. CFR was defined as the ratio of hyperemic to resting peak diastolic coronary flow velocity. Patients were divided into the three groups based on age: 17 patients aged less than 70 years (Group I), 38 patients aged 70-79 years (Group II), and 21 patients aged 80 years or more (Group III). Compared with Group I, CFR was significantly lower in Group II (p < 0.01) and Group III (p < 0.01). Multivariate linear regression analysis showed that female (β = - 0.26, p = 0.03), cigarette smoking (β = - 0.32, p = 0.004), hemoglobin level (β = - 0.40, p = 0.001) and LV mass index (β = 0.24, p = 0.03) were determinants for resting coronary flow velocity. On the other hand, age (β = -0.30, p = 0.008), hemoglobin level (β = -0.47, p < 0.001) and LV mass index (β = 0.24, p = 0.04) were determinants for hyperemic coronary flow velocity. Age was only determinant for CFR (β = -0.48, p < 0.001). Our data suggested that that aging had a decreased effect on hyperemic coronary flow velocity rather than resting coronary flow velocity, and was further associated with impaired CFR in patients with no evidence of myocardial perfusion abnormality.

Frontal QRS-T angle and left ventricular diastolic function assessed by ECG-gated SPECT in the absence of significant perfusion abnormality

The frontal QRS-T angle, defined as the angle between QRS and T-wave axes, has recently become an area of research interest. We tested the hypothesis that the frontal QRS-T angle is associated with left ventricular (LV) diastolic function in the absence of significant perfusion abnormality using ECG-gated SPECT. One hundred twenty eight patients with no significant perfusion abnormality and preserved LV ejection fraction were enrolled. The peak filling rate (PFR) and the one-third mean filling rate (1/3 MFR) were obtained as LV diastolic parameters on ECG-gated SPECT. There were 115 male and 13 female patients with a mean age of 70 ± 9 years. The PFR and 1/3 MFR were 2.1 ± 0.4/s and 1.2 ± 0.3/s, respectively. The frontal QRS-T angle was 33° ± 31°, ranging from 0° to 151°. There were significant associations of frontal QRS-T angle with PFR (r = - 0.29, p = 0.001) and 1/3 MFR (r = - 0.30, p < 0.001). Multivariate linear regression analysis showed that age (β = - 0.25, p = 0.003), heart rate (β = 0.26, p = 0.002), LV ejection fraction (β = 0.43, p < 0.001) and frontal QRS-T angle (β = - 0.16, p = 0.03) were significant factors associated with PFR. Also, heart rate (β = - 0.32, p < 0.001), LV mass index (β = - 0.19, p = 0.03), LV ejection fraction (β = 0.30, p < 0.001) and frontal QRS-T angle (β = - 0.26, p = 0.002) were significant factors associated with 1/3 MFR. Our data suggested that the frontal QRS-T angle was associated with LV diastolic function in the absence of significant perfusion abnormality.

Effects of aortic tortuosity on left ventricular diastolic parameters derived from gated myocardial perfusion single photon emission computed tomography in patients with normal myocardial perfusion

Aortic tortuosity is often found on chest radiograph, especially in aged patients. We tested the hypothesis that aortic tortuosity was associated with LV diastolic parameters derived from gated SPECT in patients with normal myocardial perfusion. One-hundred and twenty-two patients with preserved LV ejection fraction and normal myocardial perfusion were enrolled. Descending aortic deviation was defined as the horizontal distance from the left line of the aortic knob to the most prominent left line of the descending aorta. This parameter was measured for the quantitative assessment of aortic tortuosity. Peak filling rate (PFR) and one-third mean filling rate (1/3 MFR) were obtained from redistribution images as LV diastolic parameters. Descending aortic deviation ranged from 0 to 22 mm with a mean distance of 4.5 ± 6.3 mm. Descending aortic deviation was significantly correlated with age (r = 0.38, p < 0.001) and estimated glomerular filtration rate (eGFR) (r = - 0.21, p = 0.02). Multivariate linear regression analysis revealed that eGFR (β = 0.23, p = 0.02) and descending aortic deviation (β = - 0.23, p = 0.01) were significantly associated with PFR, and that only descending aortic deviation (β = - 0.21, p = 0.03) was significantly associated with 1/3 MFR. Our data suggest that aortic tortuosity is associated with LV diastolic parameters derived from gated SPECT in patients with normal myocardial perfusion.

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.

Appropriate use criteria for SPECT myocardial perfusion imaging: Are they appropriate for women?

BACKGROUND

Several studies have reported that women are more likely to receive inappropriate SPECT myocardial perfusion imaging (MPI), suggesting gender disparity in AUC determination. We investigated the impact of gender on the diagnostic and prognostic utility of AUC.

METHODS AND RESULTS

We analyzed a multi-site prospective cohort of 1511 consecutive patients (43.5% women) who underwent outpatient, community-based SPECT-MPI. Subjects were stratified into gender groups and appropriateness subgroups, and followed for 27 ± 10 months for cardiac death, myocardial infarction, and coronary revascularization. Women were more likely to receive inappropriate MPI (60.7% vs 33.8%, P < .001). Irrespective of appropriateness, women were less likely to have an abnormal MPI (6.1% vs 14.9%, P < .001), even after adjusting for clinical covariates [odds ratio = 0.40 (95% confidence interval = 0.26-0.60), P < .001]. Irrespective of appropriateness, women were at lower risk for MACE (composite of cardiac death, myocardial infarction, or coronary revascularization) after adjusting for clinical and imaging covariates [hazard ratio = 0.49 (95% confidence interval = 0.28-0.86), P = .01]. There was no interaction between gender and appropriateness group as a determinant of abnormal MPI or MACE (interaction P values ≥ .26), indicating that female gender was associated with similar relative risk of an abnormal MPI and MACE irrespective of appropriateness group. Abnormal MPI was similarly predictive of increased hazard of MACE in both genders, regardless of appropriateness (interaction P values ≥ .46).

CONCLUSION

In this multi-site cohort, there was no demonstrable gender-based differential impact of AUC on the diagnostic or prognostic utility of SPECT-MPI. The study validates the methods used in determining risk in the AUC algorithm and endorses the widespread application of AUC in men and women.

Prognostic implications of stress modality on mortality risk and cause of death in patients undergoing office-based SPECT myocardial perfusion imaging

BACKGROUND

Patients requiring vasodilator single-photon emission computed-tomography myocardial perfusion imaging (SPECT-MPI) have a higher mortality risk than those selected for exercise or vasodilator with low-level exercise SPECT-MPI. However, it is unknown whether the increased mortality is driven by cardiac deaths alone or cardiac and non-cardiac deaths.

METHODS

In a prospective cohort of 1,511 consecutive patients referred for SPECT-MPI, patients were classified according to stress test modality: exercise, adenosine with low-level exercise (AdenoEx), and adenosine. Subjects were followed for events of all-cause mortality and cause of death. Survival analyses using multivariate Cox regression and propensity score matching methods were performed.

RESULTS

During a follow-up of 4.9 ± 0.9 years, a total of 68 (4.5%) deaths occurred: 50 non-cardiac and 18 cardiac. The adenosine group had the highest annual mortality (all-cause 3.65%, non-cardiac 2.36%, cardiac 1.29%), while exercise stress had the lowest mortality (all-cause 0.42%, non-cardiac 0.37%, cardiac 0.05%) and AdenoEx had an intermediate mortality (all-cause 1.3%, non-cardiac 0.91%, cardiac 0.39%); all P values <0.001. The majority of non-cardiac deaths were attributed to cancer. Using exercise stress as a reference standard, multivariable Cox regression analyses demonstrated that adenosine stress was independently predictive of all-cause mortality [HR 3.23 (CI 1.77-5.88); P < 0.001], non-cardiac death [HR 2.67 (CI 1.34-5.31); P = 0.005], and cardiac death [HR 6.30 (CI 1.55-25.56); P = 0.010] after adjusting for univariate predictors of mortality. These findings were consistent in the subgroups of patients with normal and abnormal MPI. AdenoEx was predictive of all-cause, non-cardiac, and cardiac deaths in univariate analysis, but it was not predictive by multivariate analysis. Propensity score matched cohort analysis showed that the adenosine stress group had the highest all-cause (P < 0.001), non-cardiac (P = 0.013), and cardiac deaths (P < 0.001), while the exercise stress group had the lowest mortality of any cause.

CONCLUSIONS

The inability to perform any level of exercise during a SPECT-MPI stress is associated with high mortality risk, which is derived from both cardiac and non-cardiac deaths.

Long-Term Risk Assessment After the Performance of Stress Myocardial Perfusion Imaging

Stress-rest myocardial perfusion imaging (MPI) is a potent method for assessing the presence and magnitude of inducible myocardial ischemia. Stress MPI currently faces increased scrutiny for its therapeutic effectiveness because of the emergence of other competing means for assessing clinical risk. New data have examined the usefulness stress-rest-MPI as a predictor for long-term clinical outcomes, in contrast to its traditional role for assessing short-term cardiovascular risk. These data indicates that temporal risk is highly influenced by both the magnitude of ischemia and various baseline clinical factors. An optimized assessment of stress MPI, which includes long-term risk prediction, might improve the potential future clinical effectiveness of this imaging modality.