Excimer laser technology in percutaneous coronary interventions: Cardiovascular laser society's position paper.

Excimer Laser Coronary Atherectomy (ELCA) is a well-established therapy that emerged for the treatment of peripheral vascular atherosclerosis in the late 1980s, at a time when catheters and materials were rudimentary and associated with the most serious complications. Refinements in catheter technology and the introduction of improved laser techniques have led to their effective use for the treatment of a wide spectrum of complex coronary lesions, such as thrombotic lesions, severe calcific lesions, non-crossable or non-expandable lesions, chronic occlusions, and stent under-expansion. The gradual introduction of high-energy strategies combined with the contrast infusion technique has enabled us to treat an increasing number of complex cases with a low rate of periprocedural complications. Currently, the use of the ELCA has also been demonstrated to be effective in acute coronary syndrome (ACS), especially in the context of large thrombotic lesions.

Retrograde approach for revascularization of coronary chronic total occlusion.

Retrograde approach via collateral channels in coronary angioplasty for chronic total occlusion (CTO) can improve recanalization success rate. Most interventionalists will meet few cases where the retrograde approach will provide unequaled advantages, but many are held back from taking retrograde approach by lack of proper equipment and expertise. In this article, we give detailed description of all techniques to traverse the collateral channels, and to cross the CTO by retrograde approach. We also illustrate the difficulties in collateral channel crossing with different examples providing a basic guide for case selection purposes.

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.

Usefulness of glycoprotein IIb/IIIa inhibitors in unstable angina due to small vessel disease.

We describe the role of abciximab in unstable angina due to small vessel disease in a 58-year-old patient who was submitted to percutaneous transluminal coronary angioplasty and stenting of an occluded venous graft.

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.

Usefulness of platelet glycoprotein IIb/IIIa inhibitors in coronary stenting for reconstruction of complex lesions: procedural and 30 day outcome.

BACKGROUND: Intracoronary stent implantation during percutaneous transluminal coronary angioplasty (PTCA) has shown favorable results, reducing acute complications associated with PTCA, such as coronary artery dissection and abrupt or threatened vessel closure. However, treatment of lesions with a complex morphology and diffuse disease, requiring long or multiple coronary stents, is still associated with a poorer outcome. We investigated the hypothesis that abciximab might lead to a different outcome in patients with complex coronary lesions, which require long or multiple stent implantation. METHODS: One hundred and six patients were randomized to receive either a combination of abciximab (bolus and 12 hour infusion) and weight-adjusted low-dose heparin or weight-adjusted heparin alone and followed up to 30 days. RESULTS: The procedural success rate was 100% in both groups of patients. In the control group a composite rate of major adverse events such as any death irrespective of cause, Q wave or non-Q wave myocardial infarction, acute or subacute stent thrombosis and urgent revascularization of 15.3% was shown at 30-day follow-up. The use of abciximab reduced the composite adverse event rate to 3.7% (76% absolute reduction, p < 0.05). CONCLUSIONS: The use of abciximab during high risk stenting is safe and reduces the risk of cardiac events at 30-day follow-up as compared to standard treatment with heparin. A longer follow-up period is warranted to confirm the beneficial effects observed at 30 days with abciximab in this setting.

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.

A randomized comparison of trapidil (triazolopyrimidine), a platelet-derived growth factor antagonist, versus aspirin in prevention of angiographic restenosis after coronary artery Palmaz-Schatz stent implantation.

The aim of the study is to assess the safety of trapidil in the setting of coronary stenting and to evaluate its efficacy in reducing angiographic in-stent restenosis. One hundred eighteen patients undergoing Palmaz-Schatz stent implantation were randomly assigned to receive antiplatelet therapy using either aspirin (325 mg/d) or trapidil (400 mg/d), in combination with ticlopidine (500 mg) for the first month. At entry, both groups were comparable with regard to clinical, angiographic, and procedural characteristics. At 6-month angiographic follow-up, >50% restenosis occurred in 15 of 52 lesions (28.8%) of the aspirin group and in 14 of 47 lesions (29.8%) of the trapidil group (P=not significant, NS). At 6-month clinical follow-up, there was no difference in the two groups in the rate of adverse events (2.0% vs. 2.1%, P=NS), medication side effects (4.0% vs. 4.2%, P=NS), and peripheral vascular complications (4.0% vs. 4.2%, P=NS). In conclusion, treatment with trapidil seems to be associated with a similar incidence of stent restenosis and adverse cardiac events as compared to aspirin and could be a valuable alternative to aspirin in the setting of coronary stenting.

[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.

[Dissolution of acute stent thrombosis by abciximab bolus]. / Risoluzione di trombosi acuta di stent dopo bolo di abciximab.

Abciximab, REOPRO, a potent inhibitor of platelet aggregation via glycoprotein IIb/IIIa inhibition, has shown to be effective in the prevention of short and long-term complications of percutaneous coronary interventions. Very few reports on the role of this drug in the setting of acute stent thrombosis have been published. We report 1 case of the effectiveness of REOPRO in the complete lysis of stent thrombus with reperfusion of the coronary vessel and its collaterals. This case suggests an important role of platelets in the setting of acute stent thrombosis and a thrombolytic effect of REOPRO.

[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.

Comparison of technetium 99m-tetrofosmin and thallium-201 single photon emission computed tomographic imaging for the assessment of viable myocardium in patients with left ventricular dysfunction.

BACKGROUND: Tetrofosmin is a new technetium 99m-labeled myocardial perfusion agent that has demonstrated favorable imaging characteristics in recent clinical trials. However, it is not certain whether 99mTc-tetrofosmin compared with thallium 201 would underestimate myocardial viability in regions with left ventricular dysfunction. METHODS: To this end 15 patients (mean age 52+/-7 years) with coronary artery disease and left ventricular dysfunction (ejection fraction 35%+/-8%) documented on angiography underwent both quantitative rest-redistribution 201Tl and rest 99mTc-tetrofosmin single photon emission computed tomography imaging. RESULTS; Of 240 total segments on rest-redistribution 201Tl protocol 139 (58%) segments had irreversible 201Tl defects. Of these segments 79 (57%) had only mild to moderate reduction of 201Tl uptake (51% to 85% of normal uptake), whereas the remaining 60 (43%) had severely reduced tracer uptake (< or = 50% of normal uptake). On 99mTc-tetrofosmin protocol 180 (75%) segments had abnormal 99mTc-tetrofosmin uptake; of these segments 120 (67%) had mild to moderate reduction of 99mTc-tetrofosmin uptake, whereas 60 (33%) had severely reduced activity. Among hypokinetic regions concordance between 201Tl and 99mTc-tetrofosmin regarding myocardial viability with a cutoff point of 50% of peak activity was obtained in 28 (90%) of 31 segments (K' = 0.80), leaving only 3 of 31 regions discordant (p = NS). Similarly, among akinetic or dyskinetic regions concordance between the two tracers regarding myocardial viability was achieved in 54 (93%) regions (K' = 0.75), leaving only 4 of the 58 regions discordant (p = NS). CONCLUSIONS: These data show that when the severity of uptake was considered within abnormal segments, a similar amount of 201Tl viable regions were observed by 99mTc-tetrofosmin. Thus these two agents may provide comparable information about myocardial viability when quantitative analysis of defect severity is performed.

[Endothelin-1 variation in the coronary circulation during angioplasty with a stent implant]. / Variazione di endotelina-1 nel circolo coronarico durante angioplastica con impianto di stent.

Endothelin-1 (ET-1) is an endothelium-derived mediator with vasoconstrictive and mitogenic activity which stimulates vascular smooth muscle cell proliferation. The aim of this study was to evaluate ET-1 production during percutaneous transluminal coronary angioplasty (PTCA) and elective stent implantation. We hypothesized that the additional vessel wall trauma induced by stent deployment might be associated with a greater production of ET-1. To this end, ET-1 levels were measured in 18 patients undergoing PTCA and stenting (12 with left anterior descending coronary artery stenosis and 6 with circumflex artery lesion). The sampling sites were the coronary ostium and coronary sinus in basal conditions (before the procedure), during first balloon inflation, and 5, 20, 60 min after the end of first balloon inflation. At baseline, ET-1 levels were higher in the coronary sinus than in coronary ostium (1.58 +/- 0.22 vs 1.29 +/- 0.20 pg/ml, p < 0.001). During first balloon inflation, ET-1 coronary sinus levels significantly diminished with respect to the basal levels (1.08 +/- 0.32 vs 1.58 +/- 0.22 pg/ml, p < 0.001). Further significant variations of ET-1 levels were not detected neither following the first balloon inflation nor after stent deployment. In conclusion, the culprit lesion seems to produce most of ET-1 circulating in the coronary tree. This is demonstrated by higher ET-1 levels in the coronary sinus compared to coronary ostium at baseline, and even more by the significant ET-1 reduction in the coronary sinus during first balloon inflation. Despite our expectations, we did not detect any significant ET-1 increase during stent deployment.

The "proximal isovelocity surface area" method in assessing mitral valve area in patients with mitral stenosis and associated aortic regurgitation.

BACKGROUND: This study compares the mitral valve area determined by Doppler color mapping of the proximal isovelocity surface area (PISA) and by Doppler pressure half-time with that obtained by two-dimensional planimetry in patients affected by mitral stenosis, with and without associated aortic regurgitation. Pressure half-time frequently overestimates the mitral valve area in patients with mitral stenosis and associated aortic regurgitation. PISA is an alternative method for determining mitral valve area in mitral stenosis and is not influenced by regurgitant lesions. METHODS: We studied 76 patients with mitral stenosis; aortic regurgitation > or = 2 was present in 24 patients. The PISA was recorded from the apex and the transmitral maximal flow rate, Q (ml/s), was calculated using the hemispheric equation Q = 2 pi R2 x AV x alpha/180, where R (cm) is the maximal radius of the PISA, AV (cm/s) is the aliasing velocity and alpha/180 is a correction factor accounting for the alpha inflow angle formed by the mitral leaflets. Mitral valve area, A (cm2), was calculated by continuity equation A = Q/V, where V (cm/s) is the peak transmitral flow velocity measured by continuous wave Doppler. RESULTS: The mitral valve area by two-dimensional planimetry (range 0.5-2.4 cm2; mean 1.33 +/- 0.41 cm2) was consistent with both PISA (r = 0.83; SEE 0.23 cm2) and pressure half-time (r = 0.79; SEE 0.25 cm2) methods. Similar agreement was found for the 36 patients with mitral regurgitation and for the 30 patients in atrial fibrillation. However, in patients with aortic regurgitation > or = 2, pressure half-time overestimated two-dimensional and PISA determined mitral valve areas by 0.24 +/- 0.25 cm2 (p < 0.01). CONCLUSIONS: In patients with mitral stenosis and significant aortic regurgitation, the PISA method is more accurate than pressure half-time in assessing mitral valve area. This method may be a reliable alternative when pressure half-time is affected by aortic regurgitation and two-dimensional planimetry images are unsuitable for anatomic evaluation.