Radiation dose and prognosis of ultra-low-dose stress-first myocardial perfusion SPECT in patients with chest pain using a high-efficiency camera.

UNLABELLED: Although SPECT myocardial perfusion imaging (MPI) provides valuable information about patients with chest pain, there is growing concern regarding its radiation burden and lengthy duration. New high-efficiency (HE) cameras and stress-first protocols both offer the potential to markedly reduce radiation. No previous study has assessed outcomes and radiation doses of patients undergoing MPI on an HE-SPECT camera using an ultra-low-dose stress-first protocol. METHODS: One hundred patients presenting to the emergency department with chest pain who were candidates for stress-first MPI underwent injection of approximately 185 MBq (5 mCi) of (99m)Tc-tetrofosmin at peak stress, followed by supine and prone imaging on an HE-SPECT camera. Same-day rest imaging was performed on patients with any abnormality on imaging after stress. Radiation effective dose was calculated from administered and residual activities. Patients were contacted 3 mo after discharge, and electronic records were accessed to evaluate the need for reevaluation for chest pain, additional imaging, or cardiac events. RESULTS: Stress-only imaging was performed in 69 patients, for whom radiation effective dose averaged 0.99 mSv and study duration, 117 min. Radiation dose averaged 2.22 mSv over all patients. At 3 mo, 96 patients were free of major adverse cardiac events, repeat hospital chest pain evaluation, and repeat imaging or stress testing. One year after MPI and hospital discharge, all patients were living and without acute coronary syndrome. CONCLUSION: HE-SPECT stress-only imaging can be performed in more than two thirds of chest pain patients without a high pretest probability of a stress perfusion defect, with excellent prognosis, a radiation dose averaging 1 mSv, and a test duration of less than 2 h.

Association of coronary artery calcium with severity of myocardial ischemia in left anterior descending, left circumflex, and right coronary artery territories.

BACKGROUND: An increasing coronary artery calcium score is associated with a higher likelihood of myocardial ischemia. HYPOTHESIS: The association of the coronary calcium score with myocardial ischemia in different coronary arteries needed to be investigated. METHODS: We correlated the coronary artery calcium (CAC) score with the severity of myocardial ischemia diagnosed by myocardial perfusion imaging in the left anterior descending (LAD), left circumflex (LCX), and right coronary artery (RCA) territories in 206 patients, mean age 66 years, without cardiac stents or coronary artery surgery. RESULTS: The mean CAC score in the LAD coronary artery was 160 ± 218 in patients with no or mild ischemia and 336 ± 379 in patients with moderate or severe ischemia (P = 0.039). The mean CAC score in the LCX coronary artery was 57 ± 117 in patients with no or mild ischemia and 161 ± 191 in patients with moderate or severe ischemia (P = 0.018). The mean CAC score in the RCA was 114 ± 237 in patients with no or mild ischemia and 261 ± 321 in patients with moderate or severe ischemia (P = 0.045). Stepwise linear regression analysis showed that male gender (P < 0.0001), age (P < 0.0001), and moderate or severe ischemia (P = 0.023) were significantly associated with high LAD coronary artery CAC scores. Male gender (P < 0.0001), age (P = 0.0002), and moderate or severe ischemia (P = 0.006) were significantly associated with high LCX coronary artery CAC scores. Male gender (P < 0.0001) and age (P < 0.0001) were significantly associated with high RCA CAC scores. CONCLUSIONS: Higher CAC scores are significantly associated with moderate or severe ischemia in the LAD and LCX coronary arteries.

Incidence of myocardial infarction or stroke or death at 47-month follow-up in patients with diabetes and a predicted exercise capacity 85% during an exercise treadmill sestamibi stress test.

A treadmill exercise sestamibi stress test (TESST) was performed in 609 consecutive diabetic persons with a mean age of 70 years and no history of coronary artery disease (CAD) who were referred for a TESST because of chest pain or dyspnea. Of 609 patients, 301 (49%) had a predicted exercise capacity 85% (group B). Group A patients had a higher prevalence of myocardial ischemia (43% vs 30%, P=.0005), 2- or 3-vessel obstructive CAD (38% vs 18%, P=.001), myocardial infarction (17% vs 9%, P=.004), death (10% vs 4%, P=.008), and myocardial infarction or stroke or death at 47-month follow-up (21% vs 12%, P=.001). Stepwise Cox regression analysis showed that the only significant independent predictor for the time to development of myocardial infarction or stroke or death was a predicted exercise capacity >85% (hazard ratio, 0.52; 95% confidence interval, 0.34-0.78; P=.002). Diabetic persons with a predicted exercise capacity >85% had a 48% lower chance of myocardial infarction, stroke, or death than those with a predicted exercise capacity

Relation of bone mineral density to stress test-induced myocardial ischemia.

Dual-energy x-ray absorptiometric scans of the spine and left hip were performed before stress testing for myocardial ischemia in 629 women and 136 men (mean age 63 years) with chest pain and no previous coronary artery disease. Of the 765 patients, 254 (33%) had osteoporosis, 260 (34%) had osteopenia, and 251 (33%) had normal bone mineral density (BMD). Stress test-induced myocardial ischemia was present in 95 of 254 patients (37%) with osteoporosis, in 81 of 260 patients (31%) with osteopenia, and in 62 of 251 patients (25%) with normal BMD (p = 0.002 comparing osteoporosis with normal BMD and p = 0.007 comparing osteoporosis or osteopenia with normal BMD). Stepwise logistic regression analysis showed that patients with osteoporosis or osteopenia had a 1.7 times higher chance of stress test-induced myocardial ischemia than those with normal BMD after controlling the confounding effects of systemic hypertension, diabetes mellitus, body mass index, and age. In conclusion, patients with chest pain undergoing stress testing have a higher prevalence of stress test-induced myocardial ischemia if they have osteoporosis or osteopenia than if they have normal BMD.

Comparison of sensitivity, specificity, positive predictive value, and negative predictive value of stress testing versus 64-multislice coronary computed tomography angiography in predicting obstructive coronary artery disease diagnosed by coronary angiography.

Sixty-four-multislice coronary computed tomographic angiography (CTA) and coronary angiography were performed in 145 patients (mean age 67 +/- 10 years), and stress testing was performed in 47 of these patients to determine the sensitivity, specificity, positive predictive value, and negative predictive value of coronary CTA and of stress testing in diagnosing obstructive coronary artery disease (CAD) in patients with suspected CAD. In 145 patients, coronary CTA had 98% sensitivity, 74% specificity, 90% positive predictive value, and 94% negative predictive value in diagnosing obstructive CAD. In 47 patients, stress testing had 69% sensitivity, 36% specificity, 78% positive predictive value, and 27% negative predictive value for diagnosing obstructive CAD, whereas coronary CTA had 100% sensitivity, 73% specificity, 92% positive predictive value, and 100% negative predictive value for diagnosing obstructive CAD. In conclusion, coronary CTA has better sensitivity, specificity, positive predictive value, and negative predictive value than stress testing in diagnosing obstructive CAD.

Prevalence of an increased ascending thoracic aorta diameter diagnosed by two-dimensional echocardiography versus 64-multislice cardiac computed tomography.

The prevalence of an enlarged ascending thoracic aortic diameter (AAD) diagnosed by 2-dimensional echocardiography compared with 64-slice cardiac computed tomography (MSCT) was investigated in 97 women and 117 men (mean age 65 +/- 12 years). Enlarged AADs were diagnosed in 42 of 214 patients (20%) by echocardiography and in 45 of 214 patients (21%) by MSCT (p = NS). The sensitivity, specificity, positive predictive value, and negative predictive value of echocardiography in diagnosing an enlarged AAD using MSCT were 69%, 93%, 74%, and 92%, respectively. A Bland-Altman plot showed that the agreement for AAD measured by echocardiography and MSCT was 95% inside the 2-SD limits. In conclusion, the sensitivity, specificity, positive predictive value, and negative predictive value of 2-dimensional echocardiography in diagnosing enlarged AAD using MSCT were 69%, 93%, 74%, and 92%, respectively.

Prevalence of an increased ascending and descending thoracic aorta diameter diagnosed by multislice cardiac computed tomography in men versus women and in persons aged 23 to 50 years, 51 to 65 years, 66 to 80 years, and 81 to 88 years.

The prevalence of increased ascending thoracic aortic diameter (AAD) and increased descending thoracic aortic diameter (DAD) diagnosed using multislice cardiac computed tomography was investigated in 624 consecutive patients at an academic cardiology practice in 2006. Increased AAD (>3.7 cm) was present in 71 of 361 men (20%) and in 23 of 263 women (9%) (p <0.001). Increased DAD (>3.0 cm) was present in 26 of 339 men (8%) and in 8 of 258 women (3%) (p <0.02). Increased AAD was present in (1) 7 of 96 patients (7%) aged 23 to 50 years, (2) 22 of 234 patients (9%) aged 51 to 65 years, (3) 53 of 263 patients (20%) aged 66 to 80 years, and (4) 12 of 31 patients (39%) aged 81 to 88 years (p <0.005 comparing groups 3 and 1; p <0.001 comparing groups 4 and 1, groups 4 and 2, and groups 3 and 2; p <0.02 comparing groups 4 and 3). Increased DAD was present in (1) 0 of 96 patients (0%) aged 23 to 50 years, (2) 5 of 227 patients (2%) aged 51 to 65 years, (3) 21 of 244 patients (9%) aged 66 to 80 years, and (4) 8 of 30 patients (27%) aged 81 to 88 years (p <0.005 comparing groups 3 and 1, groups 3 and 2, and groups 4 and 3; p <0.001 comparing groups 4 and 1 and groups 4 and 2). In conclusion, men have a higher prevalence of increased AAD and DAD than women, and increasing age increases the prevalence of increased AAD and DAD.

Patients with echocardiographic aortic valve calcium or mitral annular calcium have an increased prevalence of moderate or severe coronary artery calcium diagnosed by cardiac computed tomography.

The association between aortic valve calcium (AVC) and mitral annular calcium (MAC), as diagnosed by two-dimensional echocardiography, was investigated in 138 patients (76 women and 62 men, mean age 64±8 years) seen in a private cardiology practice at the New York Medical College. Coronary artery calcium (CAC) scores were diagnosed by 64-multislice computed tomography. AVC was present in 25 of 57 patients (44%) with moderate or severe CAC (a CAC score of more than 100) and in 15 of 81 patients (19%) with no or mild CAC (a CAC score of 0 to 100), P<0.001. Moderate or severe AVC was present in nine of 57 patients (16%) with moderate or severe CAC, and in two of 81 patients (2%) with no or mild CAC, P<0.005. MAC was present in 18 of 57 patients (32%) with moderate or severe CAC, and in seven of 81 patients (9%) with no or mild CAC, P<0.001. Moderate or severe MAC was present in eight of 57 patients (14%) with moderate or severe CAC, and in two of 81 patients (2%) with no or mild CAC, P<0.001.

Comparison of prevalence of unrecognized myocardial infarction and of silent myocardial ischemia detected by a treadmill exercise sestamibi stress test in patients with versus without diabetes mellitus.

We investigated, in 287 patients with diabetes (71% men; mean age 63 +/- 8 years) and 292 age- and gender-matched patients with diabetes, the prevalence of unrecognized myocardial infarction (MI) and silent myocardial ischemia (SMI) detected by a treadmill exercise sestamibi stress test. In the patients without a history of MI, MI was diagnosed by treadmill exercise sestamibi stress test in 40 of 217 patients (18%) with diabetes and 16 of 224 patients (7%) without diabetes (p <0.001). In patients with a history of angina, SMI was diagnosed in 35 of 98 patients (36%) with diabetes and 30 of 101 patients (30%) without diabetes (p = NS). In patients without a history of angina, SMI was diagnosed in 62 of 189 patients (33%) with diabetes and 35 of 191 patients (15%) without diabetes (p <0.001). In patients with 2 or 3 risk factors, SMI was diagnosed in 58 of 144 patients (40%) with diabetes and 41 of 142 patients (29%) without diabetes (p <0.005). In patients with 0 or 1 risk factor, SMI was diagnosed in 39 of 143 patients (27%) with diabetes and 24 of 150 patients (16%) without diabetes (p <0.02). In conclusion, patients with diabetes have a higher prevalence of unrecognized MI and a higher prevalence of SMI without a history of angina than patients without diabetes.

Anomalous origin of the left main coronary artery from the right sinus of Valsalva with an intramural course identified by transesophageal echocardiography in a 14 year old with acute myocardial infarction.

Coronary artery anomalies have an incidence of 0.6% to 1.3% in angiographic studies and 0.3% in an autopsy series. Anomalous origin of the left main coronary artery (LMCA) from the right sinus of Valsalva (RSOV) represents a small fraction (1.3%) of these anomalies, with an overall prevalence of 0.017% to 0.03% in angiographic studies. The high incidence of sudden cardiac death associated with this specific anomaly during or immediately after vigorous physical exercise makes identification and appropriate surgical intervention critical. We present a case report of a 14-year-old patient with an LMCA arising from the RSOV with an initial intramural course, presenting with acute myocardial infarction (AMI) as the first indication of the anomaly. Transthoracic echocardiogram suggested this anomaly, which was confirmed by cardiac catheterization and transesophageal echocardiogram.

Prevalence of silent myocardial ischemia in persons with diabetes mellitus or impaired glucose tolerance and association of hemoglobin A1c with prevalence of silent myocardial ischemia.

Silent myocardial ischemia detected by exercise treadmill or pharmacologic sestamibi stress testing was present in 67 of 196 patients (34%) who had diabetes mellitus or impaired glucose tolerance and in 89 of 640 patients (14%) who had normal glucose tolerance (p <0.001). Among those who had diabetes mellitus or impaired glucose tolerance, silent myocardial ischemia was present in 27 of 54 patients (50%) who had a hemoglobin A1c level > or =7.6% and in 39 of 137 patients (28%) with a hemoglobin A1c level <7.6% (p <0.005).

Sensitivity, specificity, positive predictive value, and negative predictive value of the dipyridamole sestamibi stress test comparing arterial to vein conduits.

STUDY OBJECTIVES: To determine the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the dipyridamole stress test (DSST) in predicting > or = 50% obstruction of an internal mammary artery or new native coronary artery disease (CAD) compared with saphenous vein graft obstruction > or = 50% in patients with prior coronary artery surgery and symptoms. DESIGN: In 144 patients with prior coronary artery surgery who underwent a DSST within 8 +/- 7 days of coronary angiography performed because of cardiac symptoms, we investigated the sensitivity, specificity, PPV, and NPV of the DSST in predicting > or = 50% obstruction of an internal mammary artery or new native CAD (201 total arterial conduits) vs > or = 50% obstruction of saphenous vein grafts (total saphenous grafts = 246). SETTING: A university hospital. PATIENTS: The 144 patients included 88 men and 56 women, mean age 68 +/- 9 years (+/- SD). RESULTS: The DSST had a sensitivity of 81%, a specificity of 87%, a PPV of 84%, and a NPV of 84% in predicting > or = 50% obstruction of an internal mammary artery or new native CAD. The DSST had a sensitivity of 88%, a specificity of 82%, a PPV of 86%, and a NPV of 85% in predicting > or = 50% obstruction of saphenous vein grafts. CONCLUSION: There was no significant difference in sensitivity, specificity, PPV, or NPV of the DSST in predicting > or = 50% obstruction of an internal mammary artery or new native CAD vs predicting > or = 50% obstruction of saphenous vein grafts in patients with prior coronary artery surgery and cardiac symptoms.

Sensitivity, specificity, positive predictive value, and negative predictive value of the dipyridamole sestamibi stress test in predicting graft occlusion or > or = 50% new native coronary artery disease in men versus women and in patients aged > or = 65 years versus < 65 years who had prior coronary artery bypass grafting.

The sensitivity, specificity, positive predictive value, and negative predictive value of the dipyridamole sestamibi stress test (DSST) in predicting graft obstruction or > or = 50% new native coronary artery disease (CAD) in 88 men compared with 56 women with prior coronary artery bypass surgery were 96% and 94% (p = NS), 30% and 67% (p = NS), 91% and 96 % (p = NS), 50% and 57% (p = NS), respectively. The sensitivity, specificity, positive predictive value, and negative predictive value of the DSST in predicting graft obstruction or > or = 50% new native CAD in 92 patients aged < 65 years were 95% and 95% (p = NS), 50% and 40% (p = NS), 96% and 87% (p = NS), and 43% and 67% (p = NS), respectively.

Comparison of two-dimensional echocardiographic tissue harmonic imaging and gated sestamibi single-photon emission computed tomographic left ventricular ejection fraction measurements.

There was good correlation between left ventricular ejection fraction (EF) measurements employing 2-dimensional echocardiography with tissue harmonic imaging and single-photon emission computed tomography using quantitative gated scintigraphy, although in most patients, echocardiographic EF was lower. There was a high degree of agreement between these 2 techniques in assignment of EF to the categories of normal, mildly, moderately, or severely decreased. However, when EF categories did differ, echocardiography always resulted in assignment to a lower category.

Nicotine gum-induced atrial fibrillation.

A 39-year-old man with no prior history of atrial fibrillation was hospitalized with atrial fibrillation and a rapid ventricular rate. For the 7 months before presentation, he had been chewing nicotine polacrilex gum on his own. The week he first developed palpitations, he was chewing more than 1 piece of nicotine Polacrilex gum per hour during work. His diagnostic work-up during hospitalization found no cause for atrial fibrillation. He was cardioverted to sinus rhythm. At 6-month follow-up, he had not renewed chewing nicotine polacrilex gum, was in sinus rhythm, and had no history of palpitations. The temporal relation between more frequent gum usage and the excessive consumption of nicotine polacrilex chewing gum with a probable high serum nicotine level at the time the patient developed his first episode of atrial fibrillation suggests a causal relationship.