Incremental prognostic value of technetium-99m-tetrofosmin exercise myocardial perfusion imaging for predicting outcomes in patients with suspected or known coronary artery disease.

Technetium-99m (Tc-99m)-tetrofosmin is a radio isotope that has been shown to be an accurate alternative to thallium-201 for detecting coronary artery disease. However, its prognostic value is less well determined. To this end, 459 consecutive patients (mean age 58 +/- 10 years) with suspected or known coronary artery disease underwent exercise single-photon emission tomography Tc-99m-tetrofosmin scintigraphy. Follow-up, defined as the time from scanning until a soft event (revascularization procedures), a hard event (myocardial infarction and cardiac death), or patient response, lasted up to 78 months (median 38). An ischemic scintigraphic perfusion score, which takes into account both the extent and severity of reversible perfusion defects, was calculated to estimate the severity of perfusion abnormalities. Patients with normal scans were at low risk of events (yearly hard event rate 0.5% and soft event rate 0.9%). The rate of outcomes increased significantly with abnormal scans (yearly hard event rate 4.9% and soft event rate 10.3%). Statistical analysis using the Kaplan-Meyer survival curves showed a significant difference in event-free survival between patients with normal and abnormal scans. With use of Cox proportional-hazards analysis, after adjusting for prescan information, nuclear data provided incremental prognostic value for hard events (clinical and exercise data vs nuclear data; chi-square = 15.5 vs 33.4, p <0.001). Exercise single-photon emission tomographic scintigraphy using Tc-99m-tetrofosmin provides significant independent information on the subsequent risk of hard and soft events. The annual event rate for hard and soft events is <1% for patients with a normal scan. Furthermore, this tracer yields incremental prognostic information in addition to that provided by clinical and exercise data for hard events.

Long-term angiographic follow-up after successful repeat balloon angioplasty for in-stent restenosis.

BACKGROUND: Coronary stent implantation is associated with improved angiographic short-term and mid-term clinical outcome. However, restenosis rate still remains between 20 and 30%. HYPOTHESIS: The purpose of the study, performed as a prospective angiographic follow-up to detect restenosis, was to evaluate the immediate and the 6-month angiographic results of repeat balloon angioplasty for in-stent restenosis. METHODS: From April 1996 to September 1997, 335 stenting procedures performed in 327 patients underwent prospectively 6-month control angiography. Of the 96 lesions that showed in-stent restenosis (> 50% diameter stenosis) (29%), 72 underwent balloon angioplasty. RESULTS: The primary success rate was 100%. Follow-up angiogram at a mean of 6.9 +/- 2.4 months was obtained in 54 patients. Recurrent restenosis was observed in 24 of the 55 stents (44%). Repeat intervention for diffuse and body location in-stent restenosis before repeat intervention was associated with significantly higher rates of recurrent restenosis (p < 0.001 and p < 0.05, respectively). Of the 19 patients who underwent further balloon angioplasty (100% success rate), coronary angiography was performed in 18 (95%) at a mean of 8.2 +/- 2.0 months and showed recurrent restenosis in 12 patients (67%). Further repeat intervention for diffuse and severe in-stent restenosis before the second repeat intervention was associated with significantly higher rates of further recurrent restenosis (p < 0.05 and p < 0.005, respectively). CONCLUSIONS: Although balloon angioplasty can be safely, successfully, and repeatedly performed after stent restenosis, it carries a progressively high recurrence of angiographic restenosis rate during repeat 6-month follow-ups. The subgroup of patients with diffuse, severe, and/or body location in-stent restenosis proved to be at higher risk of recurrent restenosis.

Accuracy of exercise testing in the assessment of the severity of myocardial ischemia as determined by means of technetium-99m tetrofosmin SPECT scintigraphy.

BACKGROUND: The separation of patients with suspected or known coronary artery disease into low- and high-risk subgroups by means of noninvasive testing is highly relevant in the selection of patients who require further diagnostic or therapeutic investigation. We evaluated whether exercise electrocardiographic variables during exercise testing might be a means of predicting the severity of myocardial ischemia as assessed with myocardial scintigraphy. METHODS AND RESULTS: We retrospectively reviewed 816 consecutive patients (mean age, 57+/-10 years) who underwent exercise technetium-99m tetrofosmin single photon emission computed tomography (SPECT) for the assessment of suspected or known coronary artery disease. Eight independent significant predictors of the extent and severity of reversible perfusion defects (ischemic perfusion score), which when integrated in a diagnostic algorithm satisfactorily discriminated patients with no reversible perfusion defects (sensitivity, 75%; specificity, 80%) and patients with severe impaired myocardial perfusion (> or =11 ischemic perfusion score; sensitivity, 77%; specificity, 82%), were identified by means of stepwise discriminant analysis. However, patients with mildly to moderately impaired myocardial perfusion (> or =21 but <11 ischemic perfusion score) were poorly discriminated (sensitivity, 50%; specificity, 78%). The set of variables that were significant (P<.0001) for prediction included sex, myocardial infarction, exercise angina, the maximal amount of ST segment depression, rate-pressure product threshold criteria, slope of ST segment depression, ST/heart rate index, and peak exercise heart rate. CONCLUSIONS: The results of the use of clinical and electrocardiographic exercise variables satisfactorily agrees with the results from scintigraphy only for patients with no reversible perfusion defects and with severely impaired myocardial perfusion. However, it fails as an approach with universal applicability.

Diagnostic value of exercise electrocardiography for predicting a positive scintigraphic test in patients with complete right bundle branch block.

BACKGROUND: The diagnostic value of exercise electrocardiography (ECG) in patients with complete right bundle block (cRBBB) remains controversial. The aim of this study was to investigate the diagnostic accuracy of exercise ECG for predicting ischemia in the presence of cRBBB. METHODS: From a series of 1300 consecutive patients attending for exercise ECG and 99mTc-tetrofosmin single photon emission computed tomography (SPECT), we identified 38 male patients with cRBBB and 38 matched controls with normal intraventricular conduction. Patients with left ventricular hypertrophy or previous revascularization were excluded. Exercise ECG (modified Bruce protocol) was considered positive at > or = 1 mm ST horizontal or downsloping depression in > or = 2 adjacent leads. SPECT imaging at rest and post-exercise was performed at least 48 hours apart. RESULTS: The odds ratio for ischemia comparing patients with positive and negative exercise ECGs was 11.0 (95% confidence interval 2.49-48.64, p = 0.002) in controls and 2.49 (95% confidence interval 0.64-9.08, p = 0.32) in cRBBB. The prior probability of ischemia was 0.37 in controls and 0.58 with cRBBB. The posterior probability after a positive test was 0.65 in controls and 0.68 in cRBBB. Thus, the utility of the test (posterior probability minus prior probability) was greater in controls (+0.28) than in cRBBB (+0.1). This difference was most pronounced in the anterior leads V1-V4 (controls +0.63 vs cRBBB +0.01) but less significant in the lateral leads V5-V6 (controls +0.26 vs cRBBB +0.21). Similar analysis also indicated reduced diagnostic value of negative exercise ECGs in cRBBB patients. CONCLUSIONS: The diagnostic value of exercise ECG is reduced in patients with cRBBB, although ST-segment changes in the lateral ECG territory provide superior predictive accuracy to those in the anterior leads. The use of SPECT as a first-line investigation may be justified in patients with cRBBB.

Accuracy of 99mTc-tetrofosmin myocardial tomography in the evaluation of coronary artery disease.

BACKGROUND: Technetium 99m-labeled myocardial agents have been proposed as an alternative to thallium 201. The aim of this study was to assess retrospectively the accuracy of exercise myocardial 99mTc-tetrofosmin scintigraphy with tomographic imaging (SPECT) in a large group population in the evaluation of coronary artery disease. Furthermore we evaluated the relation between the severity of scintigraphic impaired myocardial perfusion and the angiographic coronary artery stenoses in patients without myocardial infarction and with stenosis localized exclusively in the proximal segment of the 3 main coronary arteries. METHODS AND RESULTS: The study group consisted of 235 consecutive patients, 204 (87%) of whom were men, with a mean age of 57+/-10 years, and with suspected or known coronary artery disease, who underwent 99mTc-tetrofosmin SPECT and coronary angiography. Furthermore, 61 patients in a low-likelihood group for coronary artery disease were also studied. Significant disease was defined by > or = 50% luminal coronary artery stenosis in > or = 1 native coronary artery or major branch or in a saphenous vein graft or arterial mammary graft. The overall sensitivity was 95%, specificity was 76%, and predictive accuracy was 95%. The normalcy rate for the low-likelihood group was 93%. Sensitivity was 71% for the left anterior descending artery, 61% for the left circumflex artery, and 73% for the right coronary artery. Specificity was 94% for the left anterior descending artery, 96% for the left circumflex artery, and 91% for the right coronary artery. Predictive accuracy was 79% for the left anterior descending artery, 78% for the left circumflex artery, and 81 % for the right coronary artery. In patients without myocardial infarction linear regression analysis between scintigraphy and angiography showed a significant correlation in patients with severe proximal coronary artery stenosis (r = 0.53, P < .002), but not in those with moderate proximal stenosis (r = 0.31, P = NS). CONCLUSIONS: This study shows that 99mTc-tetrofosmin SPECT is accurate in the detection of coronary artery disease. The relation of the severity of scintigraphic impaired myocardial perfusion and angiographic coronary artery stenosis, however, may differ significantly in patients with proximal stenosis of different severity.

[Significance of electrocardiographic projection of ST-segment depression during exercise test in the prediction of the location of regional myocardial ischemia]. / Significato della sede elettrocardiografica del sottoslivellamento del tratto ST durante prova da sforzo nel predire la distribuzione dell'ischemia regionale miocardica.

There is still some controversy whether ST segment depression during exercise testing might predict the location of myocardial ischemia. From a population of 1196 patients who underwent myocardial 99mTc-tetrofosmin exercise SPECT scintigraphy, 22 consecutive patients (20 males and 2 females, mean age 54 +/- 10 years) with no previous myocardial infarction, positive exercise testing (> or = 1 mm ST segment depression) performed in pharmacologic wash-out and angiographically documented isolated single vessel coronary artery disease (> or = 70% diameter stenosis in a main coronary artery) were selected. None of the patients showed > or = 1 mm ST segment depression exclusively in inferior leads (II-III-aVF). Eight patients (36%) showed > or = 1 mm ST segment depression exclusively in precordial leads (Group 1). The remaining 14 patients (64%) showed > or = 1 mm ST segment depression in both inferior and precordial leads (Group 2). No differences between groups were observed regarding peak exercise test parameters such as heart rate (124 +/- 28 vs 135 +/- 21 b/min, NS), rate-pressure product (22592 +/- 5323 vs 23118 +/- 4197 mmHg x b/min, NS) and exercise time (14.5 +/- 3.9 vs 15.1 +/- 2.9 min, NS) and the number of stress-induced reversible and partially reversible defects (3.3 +/- 3.4 vs 4.6 +/- 2.8, NS). All reversible and partially reversible defects were seen in the related coronary artery stenosis region. Among Group 1, 5 patient (62.5%) showed a > or = 70% stenosis of left descending coronary artery, 1 patient (12.5%) of left circumflex and 2 patients (25%) of right coronary artery. Similarly, among Group 2, 9 patients (64.3%) showed a significant stenosis of left descending coronary artery, 1 patient (7.1%) of left circumflex and 4 patients (28.6%) of right coronary artery. Thus, we were not able to show a relation between exercise ST segment depression and the location of myocardial ischemia as assessed by myocardial 99mTc-tetrofosmin SPECT scintigraphy in a population of patients selected on the basis of single coronary artery disease.

[Safety, feasibility and efficacy of a new single-wire stent in the treatment of complex coronary lesions: the angiostent]. / Sicurezza, fattibilità ed efficacia di un nuovo stent monofilamento nel trattamento delle lesioni coronariche complesse: l'angiostent.

The angiostent is a single wire, flexible, highly radiopaque, balloon expandable stent. To evaluate the feasibility and safety of the deployment of this new stent, we report the clinical and procedural results of 70 procedures performed in 51 native coronary arteries of 48 patients, with objective evidence of ischemia. The target lesion was located in the left anterior descending artery in 18 (36%) cases, in the circumflex artery in 16 (31%) cases and in the right coronary artery in 17 (33%) cases. Mean reference vessel diameter was 3.2 +/- 0.4 mm and the minimal luminal diameter was 0.4 +/- 0.3 mm, with a mean diameter stenosis of 86 +/- 10%. Type B2 and C lesions were encountered in 56% of the cases. More than one angiostent was implanted in 14 vessels and multiple stenting was accomplished with the use of different stents in 8 coronary arteries. No major complications were reported. The post-procedural minimal luminal diameter was 3.2 +/- 0.4 mm with a mean diameter stenosis of 1.4 +/- 3.7%. In 25 cases (49%) major side branches raised from the stented segment and in all but one remained patent. In conclusion, the implantation of the angiostent is safe, feasible and effective, as it can be easily deployed at the lesion site, used for the treatment of complex lesions and preserves the patency of jailed side-branches.