Temporal trends of single-photon emission computed tomography myocardial perfusion imaging in patients without prior coronary artery disease: A 22-year experience at a tertiary academic medical center.

BACKGROUND: Between 1990 and 2006, there was a large national increase in utilization of single-photon emission computed tomography myocardial perfusion imaging (SPECT) for assessment of coronary artery disease (CAD). We aim to examine the trends of SPECT test results and patients' characteristics at Mayo Clinic Rochester. METHODS: Using the Mayo Clinic nuclear cardiology database, we examined all SPECT tests performed between January 1, 1991, and December 31, 2012, in patients without prior CAD. The study cohort was divided into 5 time periods: 1991-1995, 1996-2000, 2001-2005, 2006-2010, and 2011-2012. RESULTS: There were 35,894 eligible SPECT tests (mean age 62.5 ± 12 years, 54% men). Annual utilization of SPECT increased significantly in 1992-2002 but then decreased without evidence of test substitution with stress echocardiography. There were modest changes in CAD risk factors over time. Testing of asymptomatic patients doubled (21.9% in 1991-1995 to 40% in 2006-2010) but later decreased to 33.6% in 2011-2012. Tests on patients with typical angina decreased dramatically (18.3% in 1991-1995 to 6.7% in 2011-2012). Summed stress score, summed difference score, and high-risk SPECT tests all decreased over time in both symptomatic and asymptomatic patients regardless of stress modality (exercise vs pharmacologic). CONCLUSIONS: In Mayo Clinic Rochester, annual SPECT utilization in patients without prior CAD increased in 1992-2002 but then decreased. Despite similar CAD risk factors and decreased utilization after 2003, more tests were low risk; summed stress score, summed difference score, and high-risk tests all decreased. Our findings confirm previous observations that SPECT was increasingly used in patients with a lower prevalence of CAD.

Noninvasive Stress Testing for Coronary Artery Disease.

Stress testing remains the cornerstone for noninvasive assessment of patients with possible or known coronary artery disease (CAD). The most important application of stress testing is risk stratification. Most patients who present for evaluation of stable CAD are categorized as low risk by stress testing. These low-risk patients have favorable clinical outcomes and generally do not require coronary angiography. Standard exercise treadmill testing is the initial procedure of choice in patients with a normal or near-normal resting electrocardiogram who are capable of adequate exercise. Stress imaging is recommended for patients with prior revascularization, uninterpretable electrocardiograms, or inability to adequately exercise.

Feasibility and diagnostic accuracy of exercise treadmill nitrogen-13 ammonia PET myocardial perfusion imaging of obese patients.

BACKGROUND: Treadmill exercise nitrogen-13 ((13)N)-ammonia positron emission tomography (PET) has logistical challenges and limited literature. We aimed to assess its feasibility, image quality, and diagnostic accuracy in obese and nonobese patients. METHODS AND RESULTS: Between 2009 and 2012, 10,804 patients were referred for myocardial perfusion imaging, including 300 for treadmill PET, of whom 265 were included in this study. Treadmill testing and PET were performed using standard procedures. Image quality, perfusion, and summed stress score (SSS) were assessed. Invasive coronary angiography was performed within 90 days of PET in 43 patients. Mean ± SD body mass index (BMI) was 35.7 ± 7.7 kg/m(2) (range 19.5-63.5 kg/m(2)). Feasibility of treadmill (13)N-ammonia PET was 100%. Exercise duration was less for obese patients than nonobese patients (P < .001). Image quality was rated good for 96.9% of obese and 100% of nonobese patients. For all patients, sensitivity was 86.4% and specificity was 74.4%. Diagnostic accuracy did not change significantly with increasing BMI. SSS remained significant in predicting angiographic coronary artery disease after adjustment for age, sex, and Duke treadmill score. CONCLUSIONS: Treadmill (13)N-ammonia PET is highly feasible, yields good image quality, and has moderately high diagnostic accuracy in a small subset of obese and nonobese patients who are deemed able to perform treadmill exercise.

Appropriate use criteria for stress single-photon emission computed tomography sestamibi studies: a quality improvement project.

BACKGROUND: We previously reported the application of the 2005 American College of Cardiology Foundation appropriate use criteria for stress single-photon emission computed tomography (SPECT) imaging to patients at Mayo Clinic (Rochester, MN) in 2005 and 2006. A subsequent internal quality improvement project focused on physician education in an attempt to reduce the rate of inappropriate SPECT studies. METHODS AND RESULTS: Our 2008 physician education effort, focused on 4 specific indications that accounted for 88% of the inappropriate SPECT studies, included a presentation at medical grand rounds, a publication in the staff newsletter, meetings with physician administrators, and focused presentations to departments/divisions with many ordering physicians. We then remeasured the appropriateness of SPECT studies using previously published methods. The general categories of study indications, eg, after revascularization, were similar in 273 SPECT patients in 2008 and in our 2005 (n=284) and 2006 (n=284) cohorts. There was a trend suggesting a change in the overall classification of appropriateness over time (P=0.08) and a significant change in the rate of inappropriate studies over time (P=0.018). Inappropriate studies decreased from 14.4% in 2005 to 7.0% in 2006 before initiation of the quality improvement project. After completion of the quality improvement project, inappropriate studies increased to 11.7% (P=0.06). The 95% confidence limits for the 4.7% increase in inappropriate studies after the quality improvement project included a decrease of 0.2% and an increase of 9.6%. CONCLUSIONS: This quality improvement project, focused on feedback, physician education, and remeasurement, did not reduce the rate of inappropriate stress SPECT studies in a single academic medical center. Similar limited interventions focused on physician education alone may have limited benefit. More extensive intervention may be necessary to improve the quality of care with appropriateness criteria.

The impact of ordering provider specialty on appropriateness classification.

BACKGROUND: There is limited published data comparing the appropriateness use criteria for SPECT MPI with the specialty of the ordering provider. The aim of this study was to examine if the specialty of the ordering provider affected either the ordering indication or the appropriateness of stress SPECT MPI. METHODS AND RESULTS: The ordering provider's specialty was compared with the study indication and appropriateness rating. There were modest but significant differences in general indications by specialty. For example, the Emergency Department group ordered fewer studies in asymptomatic patients (3% compared to 14%-23% in the other four referral groups). In contrast, 43% of the studies ordered by Cardiovascular Division physicians and 39% of the studies ordered by the Registered Nurse group were on post-revascularization patients, compared to 23%-31% of those ordered by the other three groups. Overall appropriateness classification did not differ among the five specialty groups (P 5 0.19). CONCLUSION: In a clinical practice where pre-operative testing using SPECT is infrequent,the rate of inappropriate studies was similar for all ordering providers. Quality improvement efforts in similar practices will likely require a broad educational focus on all ordering providers.

Early image acquisition using a solid-state cardiac camera for fast myocardial perfusion imaging.

BACKGROUND: A novel ultra-fast solid-state cardiac camera (Discovery NM 530c, General Electric) allows much shorter acquisition times compared to standard dual-detector SPECT cameras. This design enables investigation of the potential for early myocardial perfusion imaging (MPI) following a rest injection of technetium-99m (Tc-99m) rather than the conventional 45-60 minute delay in image acquisition. METHODS: A total of 30 patients underwent MPI at rest using Tc-99m sestamibi (n = 9) or tetrofosmin (n = 21). A 12 minute image acquisition in list mode was performed immediately following isotope injection. Patients also underwent a conventional delayed image acquisition 60 minutes following the rest isotope injection (image acquisition over 4 minutes). The immediate 12 minute acquisition was divided into three 4-minute intervals for image reconstruction (0-4, 4-8, and 8-12 minutes). The perfusion images were interpreted by two experienced physicians who evaluated each study for overall image quality (good, acceptable, or unacceptable) and graded each image using the summed rest score (SRS) and the standard 17-segment, 5-point scale model. RESULTS: The images acquired in the 0-8 minute time interval were predominantly uninterpretable due to excessive blood pool uptake. The images acquired in the 8-12 minute time interval were interpretable and compared to the conventional images obtained at 60 minutes. Overall image quality was better on the 60 minute image (17 good, 13 acceptable) compared with 8-12 minute image (3 good, 25 acceptable, 2 unacceptable). Sixteen of the 30 patients had an improvement in overall image quality by at least one category using the 60 minute delayed image. Nine of the 30 patients (2 Tc-99m sestamibi; 7 Tc-99m tetrofosmin) had at least one uninterpretable myocardial segment due to liver and/or bowel overlapping the myocardium on the 8-12 minute images vs 1 patient (1 myocardial segment) with this problem on the 60 minute delayed images (P = .005). Uninterpretable segments (total of 16) on the 8-12 minute images were confined to the apex and inferior wall. The mean SRS of the interpretable 8-12 minute images (n = 21) was 3.2 (95% confidence intervals; 1.0, 5.4) compared to 1.6 (95% confidence intervals; 0, 3.3) on the 60 minute delayed images in those patients (P = .005). CONCLUSIONS: Overall image quality was better with fewer uninterpretable studies and a lower SRS on the rest images obtained at 60 minutes compared to early image acquisition (8-12 minutes following isotope injection). These findings do not support the routine use of early image acquisition with this new solid-state ultra-fast camera system.

Characterization of Aerosol Generation During Various Intensities of Exercise.

BACKGROUND: Characterization of aerosol generation during exercise can inform the development of safety recommendations in the face of COVID-19. RESEARCH QUESTION: Does exercise at various intensities produce aerosols in significant quantities? STUDY DESIGN AND METHODS: In this experimental study, subjects were eight healthy volunteers (six men, two women) who were 20 to 63 years old. The 20-minute test protocol of 5 minutes rest, four 3-minute stages of exercise at 25%, 50%, 75%, and 100% of age-predicted heart rate reserve, and 3 minutes active recovery was performed in a clean, controlled environment. Aerosols were measured by four particle counters that were place to surround the subject. RESULTS: Age averaged 41 ± 14 years. Peak heart rate was 173 ± 17 beat/min (97% predicted); peak maximal oxygen uptake was 33.9 ± 7.5 mL/kg/min; and peak respiratory exchange ratio was 1.22 ± 0.10. Maximal ventilation averaged 120 ± 23 L/min, while cumulative ventilation reached 990 ± 192 L. Concentrations increased exponentially from start to 20 minutes (geometric mean ± geometric SD particles/liter): Fluke >0.3 µm = 66 ± 1.8 → 1605 ± 3.8; 0.3-1.0 µm = 35 ± 2.2 → 1095 ± 4.6; Fluke 1.0-5.0 µm = 21 ± 2.0 → 358 ± 2.3; P-Trak anterior = 637 ± 2.3 → 5148 ± 3.0; P-Trak side = 708 ± 2.7 → 6844 ± 2.7; P-Track back = 519 ± 3.1 → 5853 ± 2.8. All increases were significant at a probability value of <.05. Exercise at or above 50% of predicted heart rate reserve showed statistically significant increases in aerosol concentration. INTERPRETATION: Our data suggest exercise testing is an aerosol-generating procedure and, by extension, other activities that involve exercise intensities at or above 50% of predicted heart rate reserve. Results can guide recommendations for safety of exercise testing and other indoor exercise activities.

Mitigation of Aerosols Generated During Exercise Testing With a Portable High-Efficiency Particulate Air Filter With Fume Hood.

BACKGROUND: The role of portable high-efficiency particulate air (HEPA) filters for supplemental aerosol mitigation during exercise testing is unknown and might be relevant during COVID-19 pandemic. RESEARCH QUESTION: What is the effect of portable HEPA filtering on aerosol concentration during exercise testing and its efficiency in reducing room clearance time in a clinical exercise testing laboratory? STUDY DESIGN AND METHODS: Subjects were six healthy volunteers aged 20 to 56 years. In the first experiment, exercise was performed in a small tent with controlled airflow with the use of a stationary cycle, portable HEPA filter with fume hood, and particle counter to document aerosol concentration. Subjects performed a four-stage maximal exercise test that lasted 12 min plus 5 min of pretest quiet breathing and 3 min of active recovery. First, they exercised without mitigation then with portable HEPA filter running. In a separate experiment, room aerosol clearance time was measured in a clinical exercise testing laboratory by filling it with artificially generated aerosols and measuring time to 99.9% aerosol clearance with heating, ventilation, and air conditioning (HVAC) only or HVAC plus portable HEPA filter running. RESULTS: In the exercise experiment, particle concentrations reached 1,722 ± 1,484/L vs 96 ± 124/L (P < .04) for all particles (>0.3 µm), 1,339 ± 1,281/L vs 76 ± 104/L (P < .05) for smaller particles (0.3 to 1.0 µm), and 333 ± 209/L vs 17 ± 19/L (P < .01) for larger particles (1.0 to 5.0 µm) at the end of the protocol in a comparison of mitigation vs portable HEPA filter. Use of a portable HEPA filter in a clinical exercise laboratory clearance experiment reduced aerosol clearance time 47% vs HVAC alone. INTERPRETATION: The portable HEPA filter reduced the concentration of aerosols generated during exercise testing by 96% ± 2% for all particle sizes and reduced aerosol room clearance time in clinical exercise testing laboratories. Portable HEPA filters therefore might be useful in clinical exercise testing laboratories to reduce the risk of COVID-19 transmission.

Prevalence of Transthyretin Amyloid Cardiomyopathy in Heart Failure With Preserved Ejection Fraction.

Importance: Heart failure (HF) with preserved ejection fraction (HFpEF) is common, is frequently associated with ventricular wall thickening, and has no effective therapy. Transthyretin amyloid cardiomyopathy (ATTR-CM) can cause the HFpEF clinical phenotype, has highly effective therapy, and is believed to be underrecognized. Objective: To examine the prevalence of ATTR-CM without and with systematic screening in patients with HFpEF and ventricular wall thickening. Design, Setting, and Participants: This population-based cohort study assessed ATTR-CM prevalence in 1235 consecutive patients in southeastern Minnesota with HFpEF both without (prospectively identified cohort study) and with (consenting subset of cohort study, n = 286) systematic screening. Key entry criteria included validated HF diagnosis, age of 60 years or older, ejection fraction of 40% or greater, and ventricular wall thickness of 12 mm or greater. In this community cohort of 1235 patients, 884 had no known ATTR-CM, contraindication to technetium Tc 99m pyrophosphate scanning, or other barriers to participation in the screening study. Of these 884 patients, 295 consented and 286 underwent scanning between October 5, 2017, and March 9, 2020 (community screening cohort). Exposures: Medical record review or technetium Tc 99m pyrophosphate scintigraphy and reflex testing for ATTR-CM diagnosis. Main Outcomes and Measures: The ATTR-CM prevalence by strategy (clinical diagnosis or systematic screening), age, and sex. Results: A total of 1235 patients participated in the study, including a community cohort (median age, 80 years; interquartile range, 72-87 years; 630 [51%] male) and a community screening cohort (n = 286; median age, 78 years; interquartile range, 71-84 years; 149 [52%] male). In the 1235 patients in the community cohort without screening group, 16 patients (1.3%; 95% CI, 0.7%-2.1%) had clinically recognized ATTR-CM. The prevalence was 2.5% (95% CI, 1.4%-4.0%) in men and 0% (95% CI, 0.0%-0.6%) in women. In the 286 patients in the community screening cohort, 18 patients (6.3%; 95% CI, 3.8%-9.8%) had ATTR-CM. Prevalence increased with age from 0% in patients 60 to 69 years of age to 21% in patients 90 years and older (P < .001). Adjusting for age, ATTR-CM prevalence differed by sex, with 15 of 149 men (10.1%; 95% CI, 5.7%-16.1%) and 3 of 137 women (2.2%; 95% CI, 0.4%-6.3%) having ATTR-CM (P = .002). Conclusions and Relevance: In this cohort study based in a community-based setting, ATTR-CM was present in a substantial number of cases of HFpEF with ventricular wall thickening, particularly in older men. These results suggest that systematic evaluation can increase the diagnosis of ATTR-CM, thereby providing therapeutically relevant phenotyping of HFpEF.

Temporal trends in compliance with appropriateness criteria for stress single-photon emission computed tomography sestamibi studies in an academic medical center.

BACKGROUND: The purpose of this study was to apply published appropriateness criteria for single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) in a single academic medical center to determine if the percentage of inappropriate studies was changing over time. In a previous study, we applied the American College of Cardiology Foundation/American Society of Nuclear Cardiology (ASNC) appropriateness criteria for stress SPECT MPI and reported that 14% of stress SPECT studies were performed for inappropriate reasons. METHODS: Using similar methodology, we retrospectively examined 284 patients who underwent stress SPECT MPI in October 2006 and compared the findings to the previous cohort of 284 patients who underwent stress SPECT MPI in May 2005. RESULTS: The indications for testing in the 2 cohorts were very similar. The overall level of agreement in characterizing categories of appropriateness between 2 experienced cardiovascular nurse abstractors was good (kappa = 0.68), which represented an improvement from our previous study (kappa = 0.56). There was a significant change between May 2005 and October 2006 in the overall classification of categories for appropriateness (P = .024 by chi(2) statistic). There were modest, but insignificant, increases in the number of patients who were unclassified (15% in the current study vs 11% previously), appropriate (66% vs 64%), and uncertain (12% vs 11%). Only 7% of the studies in the current study were inappropriate, which represented a significant (P = .004) decrease from the 14% reported in the 2005 cohort. CONCLUSIONS: In the absence of any specific intervention, there was a significant change in the overall classification of SPECT appropriateness in an academic medical center over 17 months. The only significant difference in individual categories was a decrease in inappropriate studies. Additional measurements over time will be required to determine if this trend is sustainable or generalizable.

Stress Testing in the Evaluation of Stable Chest Pain in a Community Population.

OBJECTIVE: To evaluate the use of stress testing in a community population with de novo stable chest pain, a normal resting electrocardiogram (ECG), and the ability to exercise. PATIENTS AND METHODS: We identified eligible patients by searching the electronic medical record of all outpatients seen at Mayo Clinic Rochester from January 1, 2010, through December 31, 2013. We determined the frequency of initial exercise stress testing, computed tomography coronary angiography, and invasive coronary angiography, as well as the use of subsequent second procedures (including percutaneous coronary intervention [PCI] and coronary artery bypass grafting) within 90 days. Patients were followed for 5 years for death, nonfatal myocardial infarction, and hospitalization for unstable angina. RESULTS: The data search identified 1175 patients with chest pain and normal resting ECGs. Only 331 patients underwent cardiac testing. A slight majority (185; 55.9%) underwent an exercise ECG alone. The remainder underwent exercise echocardiography (112; 33.8%), exercise single-photon-emission computed tomography (32; 9.7%), or computed tomography coronary angiography (2; 0.9%). Few patients (30; 9.1%) required additional testing within 90 days. Of the 14 patients (4.2%) who underwent invasive coronary angiography, 12 (85.7%) had significant coronary artery disease, and were referred for percutaneous coronary intervention or coronary artery bypass grafting. At 5 years, the mortality rate was 1.2%, and the combined event rate was 3.8%. CONCLUSION: Most community patients with chest pain and a normal resting ECG do not require further cardiac evaluation. In patients who require testing, and are able to exercise, noninvasive stress testing is preferred. Invasive coronary angiography is applied selectively and associated with a high rate of significant coronary artery disease and referral to coronary revascularization. Long-term outcomes are excellent.

Stress single photon emission computed tomography for detection of coronary artery disease and risk stratification of asymptomatic patients at moderate risk.

BACKGROUND: The American College of Cardiology Foundation/American Society of Nuclear Cardiology appropriateness criteria document assigns single photon emission computed tomography myocardial perfusion imaging (SPECT MPI) a rating of uncertain for detection and risk assessment of coronary artery disease (CAD) in asymptomatic patients at moderate risk. METHODS AND RESULTS: The nuclear cardiology database was used to identify 260 asymptomatic patients (67 +/- 8 years, 72% men) without known CAD who were at moderate CAD risk according to the Framingham risk score. SPECT MPI images were categorized using the summed stress score (SSS). Mean follow-up 9.9 +/- 3.0 years. Abnormal SPECT MPI scans were present in 142 patients (55%). By SSS categories, SPECT scans were low-risk in 67%, intermediate-risk in 20%, and high-risk in 13% of patients. Overall survival at 10 years was 79%, significantly better than the age- and gender-matched Minnesota general population (P < 0.001). Survival was 60% for patients with high-risk scans (95% CI 45-80%), 79% with intermediate-risk scans (95% CI 69-91%), and 83% with low-risk scans (95% CI 77-88%) (P = 0.03), including 84% (95% CI 77-91%) with normal scans. CONCLUSIONS: In this retrospectively identified group of asymptomatic patients at moderate CAD risk, stress SPECT MPI was effective for the detection and risk stratification of CAD. Average annual mortality was 4.0% in patients with high-risk scans vs 1.6% in patients with normal scans.

Novel solid-state-detector dedicated cardiac camera for fast myocardial perfusion imaging: multicenter comparison with standard dual detector cameras.

OBJECTIVE: To compare the diagnostic performance of a new dedicated ultrafast solid-state cardiac camera (Discovery NM 530c [DNM]) with standard dual detector cameras (S-SPECT) in myocardial perfusion imaging. The primary goal was a per-patient analysis of diagnostic performance of the DNM using S-SPECT as the reference standard. METHODS AND RESULTS: In total, 168 patients underwent one-day Tc-99m tetrofosmin rest/stress myocardial perfusion SPECT. DNM and S-SPECT images were obtained with the same injected doses. The DNM camera uses an array of cadmium zinc telluride pixilated detectors and a multipinhole collimator simultaneously imaging all cardiac views with no moving parts. Rest and stress acquisition times were 4 and 2 minutes for DNM and 14 and 12 minutes for S-SPECT. Two blinded readers independently interpreted all scans on a patient level and on a vascular territory level using a standard five-point scale. Interobserver differences were resolved by a third observer. Agreement between DNM and S-SPECT for presence or absence of myocardial perfusion defects on a per-patient analysis was 91.9% and 92.5%, respectively. Correlation coefficients of rest and stress left ventricular ejection fractions were 0.87 (P < .01) and 0.90 (P < .01). CONCLUSION: The diagnostic performance of DNM is comparable to that of S-SPECT on a per-patient basis. However, superior image quality can be achieved with significantly shorter acquisition times with DNM because of improved count sensitivity and image contrast over S-SPECT.

Abnormal electron beam computed tomography results: the value of repeating myocardial perfusion single-photon emission computed tomography in the ongoing assessment of coronary artery disease.

OBJECTIVE: To determine whether asymptomatic patients with atherosclerosis, indicated by the presence of coronary artery calcium on electron beam computed tomography, are at enough risk for progression of disease to justify a repeated stress single-photon emission computed tomography (SPECT) examination after an initial normal to low-risk perfusion study. PATIENTS AND METHODS: We retrospectively identified patients who had abnormal results on electron beam computed tomography (coronary artery calcium score > 0) and normal to low-risk results on SPECT (defined as a summed stress score of 0-3) within a 3-month period from January 1, 1995, to October 31, 2002. Of the 504 identified patients, 285 remained after exclusion criteria were applied. Of the 285 patients, 69 (mean +/- SD age, 58.2 +/- 7.6 years; 91% male) underwent at least 1 repeated myocardial perfusion SPECT imaging study within 4 years of their initial assessment as normal or at low risk without recurrence of symptoms. The value of repeated SPECT imaging was assessed by detection of a substantial change in the repeated SPECT study and by documentation of a clinical event (death, nonfatal myocardial infarction, or revascularization). Follow-up was 100% complete at a mean of 4.3 +/- 1.6 years. RESULTS: Only 4 patients (6%) had a substantial progression in their SPECT risk category; substantial changes on the SPECT scans occurred only in patients with a coronary artery calcium score greater than 100. Three patients underwent revascularization, yielding a 5-year rate for survival free of revascularization of 94% (95% confidence interval, 88%-100%). No deaths or nonfatal myocardial infarctions were reported. CONCLUSION: The principal findings of this study indicate that asymptomatic patients with initial normal or low-risk results from stress SPECT performed because of abnormal coronary artery calcium scores who remain asymptomatic are at low risk of death, myocardial infarction, or coronary revascularization. Three patients underwent revascularization by percutaneous coronary intervention despite the absence of symptoms. A substantial change in SPECT results (defined as progression from normal or low-risk summed stress score to intermediate- or high-risk summed stress score) affected 6% of patients and was not associated with any adverse hard events (nonfatal myocardial infarction or death).

Isolated left ventricular basal ballooning phenotype of transient cardiomyopathy in young women.

This report describes a variant of transient regional left ventricular dysfunction in which isolated basal left ventricular akinesia with normal mid-ventricular (papillary-level) wall motion and apical hypercontractility were noted in young women (mean age 31 years). This finding was demonstrated in 3 consecutive patients; the first patient was experiencing emotional life-altering events, and the second presented with an acute flare of multiple sclerosis. The third patient presented < 24 hours after methamphetamine use. Coronary angiography demonstrated normal epicardial coronary arteries in all patients. Wall motion abnormalities resolved within 2 to 6 weeks. In conclusion, the entity described in this report is reminiscent of apical ballooning ("Tako-Tsubo"), mid-ventricular ballooning, and apical sparing syndromes; however, isolated basal left ventricular involvement has not been previously described and is a newer variant in the spectrum of transient cardiomyopathies. The pathophysiology of this entity has not been elucidated. A unifying feature between the transient cardiomyopathic syndromes most likely is in the concentration, distribution, and activity of cardiac adrenergic receptors.

Temporal Trends of Single-Photon Emission Computed Tomography Myocardial Perfusion Imaging in Patients With Coronary Artery Disease: A 22-Year Experience From a Tertiary Academic Medical Center.

BACKGROUND: There has been a gradual decline in the prevalence of abnormal stress single-photon emission computed tomography (SPECT) myocardial perfusion imaging studies among patients without history of coronary artery disease (CAD). The trends of SPECT studies among patients with known CAD have not been evaluated previously. METHODS AND RESULTS: We assessed the Mayo Clinic nuclear cardiology database for all stress SPECT tests performed between January 1991 and December 2012 in patients with history of CAD defined as having previous myocardial infarction, percutaneous coronary intervention, and coronary artery bypass grafting. The study cohort was divided into 5 time periods: 1991 to 1995, 1996 to 2000, 2001 to 2005, 2006 to 2010, and 2011 to 2012. There were 19 373 patients with a history of CAD who underwent SPECT between 1991 and 2012 (mean age, 66.2±10.9 years; 75.4% men). Annual utilization of SPECT in these patients increased from an average of 495 tests per year in 1991 to 1995 to 1425 in 2003 and then decreased to 552 tests in 2012 without evidence for substitution with other stress modalities. Asymptomatic patients initially increased until 2006 and then decreased. Patients with typical angina decreased, whereas patients with dyspnea and atypical angina increased. High-risk SPECT tests significantly decreased, and the percentage of low-risk SPECT tests increased despite decreased SPECT utilization between 2003 and 2012. Almost 80% of all tests performed in 2012 had a low-risk summed stress score compared with 29% in 1991 (P<0.001). CONCLUSIONS: In Mayo Clinic, Rochester, annual SPECT utilization in patients with previous CAD increased between 1992 and 2003, but then decreased after 2003. High-risk SPECT tests declined, whereas low-risk tests increased markedly. Our results suggest that among patients with a history of CAD, SPECT was being increasingly utilized in patients with milder CAD. This trend parallels reduced utilization of other stress modalities, coronary angiography, reduced smoking, and greater utilization of optimal medical therapy for prevention and treatment of CAD.

Handheld echocardiography during hospitalization for acute myocardial infarction.

BACKGROUND: Handheld echocardiography (HHE) is concordant with standard transthoracic echocardiography (TTE) in a variety of settings but has not been thoroughly compared to traditional TTE in patients with acute myocardial infarction (AMI). HYPOTHESIS: Completed by experienced operators, HHE provides accurate diagnostic capabilities compared with standard TTE in AMI patients. METHODS: This study prospectively enrolled patients admitted to the coronary care unit with AMI. Experienced sonographers performed HHE with a V-scan. All patients underwent clinical TTE. Each HHE was interpreted by 2 experts blinded to standard TTE. Agreement was assessed with κ statistics and concordance correlation coefficients. RESULTS: Analysis included 82 patients (mean age, 66 years; 74% male). On standard TTE, mean left ventricular (LV) ejection fraction was 46%. Correlation coefficients between HHE and TTE were 0.75 (95% confidence interval: 0.66 to 0.82) for LV ejection fraction and 0.69 (95% confidence interval: 0.58 to 0.77) for wall motion score index. The κ statistics ranged from 0.47 to 0.56 for LV enlargement, 0.55 to 0.79 for mitral regurgitation, and 0.44 to 0.57 for inferior vena cava dilatation. The κ statistics were highest for the anterior (0.81) and septal (0.71) apex and lowest for the mid inferolateral (0.36) and basal inferoseptal (0.36) walls. CONCLUSIONS: In patients with AMI, HHE and standard TTE demonstrate good correlation for LV function and wall motion. Agreement was less robust for structural abnormalities and specific wall segments. In experienced hands, HHE can provide a focused assessment of LV function in patients hospitalized with AMI; however, HHE should not substitute for comprehensive TTE.

Usefulness for Predicting Cardiac Events After Orthotopic Liver Transplantation of Myocardial Perfusion Imaging and Dobutamine Stress Echocardiography Preoperatively.

Patients undergoing orthotopic liver transplantation have high rates of cardiac morbidity and mortality. Although guidelines recommend noninvasive stress testing as part of the preoperative evaluation, little data have evaluated clinical outcomes following orthotopic liver transplantation. A retrospective study at 2 high-volume liver transplantation centers was performed. All patients undergoing noninvasive stress testing (myocardial perfusion imaging [MPI] or dobutamine stress echocardiography [DSE]) over a 5-year period were included. Descriptive analyses, including clinical outcomes and perioperative and postoperative ischemic events, were performed. Comparisons were made between subsets of patients within each stress modality based on abnormal versus normal results. A total of 506 patients were included, of which 343 underwent DSE and 163 MPI. Few patients had abnormal results, with 19 (5.5%) in the DSE group and 13 (8%) in the MPI group. Perioperative and postoperative cardiac complications were low (n = 20, 5.8% and n = 3, 0.9% in DSE group and n = 15, 9.2% and n = 3, 1.8% in MPI group). Comparisons between abnormal versus normal findings showed a trend toward periprocedural cardiac complications in the abnormal DSE group (n = 3, 15.8% vs n = 17, 5.25%; p = 0.09) with no difference in 6-month postprocedural complications (n = 0 vs n = 3, 0.9%; p = 1.0). In the MPI group, a trend toward periprocedural ischemic complications (n = 3, 23.1% vs n = 12, 8%; p = 0.1) was noted with no difference in 6-month postprocedural complications (n = 0 vs n = 3, 2%; p = 1.0). In conclusion, our study found a significantly lower than reported cardiac event rate. In addition, it demonstrated that ischemic cardiac events are uncommon in patients with normal stress testing.