Prediction of high on-treatment platelet reactivity in clopidogrel-treated patients with acute coronary syndromes.

BACKGROUND: About 40% of clopidogrel-treated patients display high platelet reactivity (HPR). Alternative treatments of HPR patients, identified by platelet function tests, failed to improve their clinical outcomes in large randomized clinical trials. A more appealing alternative would be to identify HPR patients a priori, based on the presence/absence of demographic, clinical and genetic factors that affect PR. Due to the complexity and multiplicity of these factors, traditional statistical methods (TSMs) fail to identify a priori HPR patients accurately. The objective was to test whether Artificial Neural Networks (ANNs) or other Machine Learning Systems (MLSs), which use algorithms to extract model-like 'structure' information from a given set of data, accurately predict platelet reactivity (PR) in clopidogrel-treated patients. METHODS: A complete set of fifty-nine demographic, clinical, genetic data was available of 603 patients with acute coronary syndromes enrolled in the prospective GEPRESS study, which showed that HPR after 1month of clopidogrel treatment independently predicted adverse cardiovascular events in patients with Syntax Score >14. Data were analysed by MLSs and TSMs. ANNs identified more variables associated PR at 1month, compared to TSMs. RESULTS: ANNs overall accuracy in predicting PR, although superior to other MLSs was 63% (95% CI 59-66). PR phenotype changed in both directions in 35% of patients across the 3 time points tested (before PCI, at hospital discharge and at 1month). CONCLUSIONS: Despite their ability to analyse very complex non-linear phenomena, ANNs or MLS were unable to predict PR accurately, likely because PR is a highly unstable phenotype.

Optimisation of therapeutic strategies for ST-segment elevation acute myocardial infarction: the impact of a territorial network on reperfusion therapy and mortality.

OBJECTIVE: To assess the clinical impact of a regional network for the treatment of ST-segment elevation myocardial infarction (STEMI). METHODS: All patients with STEMI (n = 1823) admitted to any of the hospitals of an area with one million inhabitants during the year 2002 (n = 858)-that is, before the network was implemented, and in 2004 (n = 965), the year of full implementation of the network, were enrolled in this study. The primary evaluation was in-hospital mortality. Secondary outcomes included the incidence of major adverse cardiac and cerebrovascular events (MACCE), defined as death, myocardial infarction, stroke and coronary revascularisation procedures over 1-year follow-up. RESULTS: Between 2002 and 2004, there was a major change in reperfusion strategy: primary angioplasty increased from 20.2% to 65.6% (p<0.001), fibrinolytic therapy decreased from 38.2% to 10.7% (p<0.001) and the rate of patients not undergoing reperfusion was reduced from 41.6% to 23.7% (p<0.001). In-hospital mortality decreased from 17.0% to 12.3% (p = 0.005), and this reduction was sustained at 1-year follow-up (23.9% in 2002 and 18.8% in 2004, p = 0.009). Similarly, the 1-year incidence of all MACCE was reduced from 39.5% in 2002 to 34.3% in 2004 (p = 0.01). CONCLUSIONS: Organisation of a territorial network for STEMI is associated with increased rates of reperfusion therapy and reduction of in-hospital and 1-year mortality.

Ultrasound-assisted stent implantation in small size coronary arteries: a pilot study.

BACKGROUND: Many studies have indicated that a small lumen size is one of the most important predictors of acute events and of late restenosis after balloon angioplasty or stent implantation. In the last few years many studies have shown that intravascular ultrasound (IVUS) guidance makes it possible to optimize stent implantation. The aim of this pilot study was to evaluate the feasibility and safety of IVUS imaging of small vessels. Secondary endpoints were the immediate and long-term results of IVUS-guided elective BeStent implantation in small vessels. METHODS: Fourteen symptomatic patients with small coronary vessel (mean angiographic reference diameter 2.3 +/- 0.2 mm) disease underwent IVUS-guided BeStent implantation. IVUS success was defined as the achievement of a final minimal intrastent cross-sectional area (CSA) > 90% of the smaller reference lumen CSA. RESULTS: IVUS evaluation was feasible in all patients without any clinical or angiographic adverse events. Procedural success was achieved in all patients with implantation of a BeStent 15 mm. No major complication (death, myocardial infarction, stent acute or subacute thrombosis, coronary artery bypass, re-coronary angioplasty) occurred during the in-hospital phase. Two non-flow-limiting, asymptomatic coronary dissections were detected after stent expansion. The post-stenting lesion stenosis rate decreased from 72.9 +/- 12.9% to 0.75 +/- 11.7% with an acute gain of 1.8 +/- 0.4 mm. The final IVUS minimal stent CSA was 5.6 +/- 1.1 mm2. The IVUS criteria of adequate stent expansion were reached in 11 (78.6%) patients. At 6 months of follow-up, the rate of angiographically diagnosed in-stent restenosis was 30.7%; the 6-month late loss in stent diameter was 1.1 +/- 0.6 mm. No patient died or presented with a myocardial infarction. The target lesion revascularization rate was 30.7%. CONCLUSIONS: Coronary IVUS-guided stenting can be performed in small vessels with a high success rate and low incidence of in-hospital complications. However, despite these encouraging short-term results, the long-term clinical and angiographic outcome is less favorable. Further larger and randomized IVUS studies, probably employing more aggressive IVUS criteria, are needed to clarify the true role of IVUS guidance in this particular field.

Long-term follow-up of stent implantation versus stent-like angioplasty in unstable angina.

Stent-like plain old balloon angioplasty (POBA, < or = 30% residual diameter stenosis) in patients with stable angina resulted in a clinical and angiographic long-term outcome equivalent to stenting. In unstable angina POBA showed lower acute and long-term efficacy than in the stable setting. Data comparing stent-like POBA and coronary stenting in unstable angina are lacking in the literature. The aim of this retrospective single-center study was to compare the long-term effectiveness of stent-like POBA and coronary stenting in unstable angina. From January 1996 to December 1996 we retrospectively examined 187 consecutive patients with unstable angina who underwent coronary angioplasty on a native vessel: 135 had coronary stenting in addition to POBA and 50 achieved a stent-like result with POBA. Two patients, with major contraindication to coronary stenting, who did not reach a stent-like angiographic result, were also treated with only POBA but were excluded from the study. Stent implantation indications were: elective (54 stents, 30%), suboptimal angiographic result (104 stents, 58%), and bail-out situation (21 stents, 12%). Stent implantation showed high angiographic (98.5%) and clinical (95.5%) success. Stent thrombosis occurred only in 2 patients (1.5%). At quantitative coronary angiography the stent group showed a higher post-procedure minimal lumen diameter (2.74 +/- 1.25 vs 2.27 +/- 0.58 mm, p = 0.025), acute gain (1.95 +/- 1.28 vs 1.43 +/- 0.57 mm, p = 0.007) and lower residual stenosis diameter (13.89 +/- 7.43 vs 20.4 +/- 7.28%, p = 0.001) than the stent-like POBA group. At 1-year follow-up the stent group showed a higher event-free survival rate (77.9 vs 64.6%, p = 0.009) mainly due to lower recurrence of angina and repetition of percutaneous procedures. Stent-like POBA procedure and baseline lesion length > or = 10 mm proved to be the only independent predictors of long-term ischemic event occurrence. In conclusion, in unstable angina, stent implantation appears more effective than stent-like POBA to avoid long-term ischemic complications.

Coronary stenting for unstable angina: predictors of 30-day and long-term clinical outcome.

BACKGROUND: Unstable angina is usually caused by acute thrombosis superimposed on a fissured plaque. Coronary artery stenting has been shown to improve short- and long-term results of coronary angioplasty in mainly stable patients with one-vessel disease, but it is uncertain whether its use in an unstable clinical setting can be safe and useful. This study sought to evaluate the results of coronary stenting in unstable angina and to determine patient, lesion and procedure-related predictors of 30-day and long-term ischemic events. METHODS: We studied 266 consecutive patients (mean age 62 +/- 9 years) with unstable angina who underwent coronary artery stenting. The procedure was performed electively in 24%, in bailout situations in 11% and for a suboptimal result of conventional angioplasty in 65%. After stent implantation, patients were treated with anticoagulation (61) on combined antiplatelet therapy (200). Multivariate logistic regression analyses were performed to determine 30-day and long-term predictive factors of ischemic complications. RESULTS: Procedural success was obtained in 261 patients (98.1%). During the first 30 days after stenting, one patient died from cardiogenic shock (0.3%) and six (22%) suffered a non-fatal Q-wave myocardial infarction. Patients with combined antiplatelet therapy had a significantly lower stent thrombosis rate (1.5% versus 11.4%, P = 0.002) than those treated with anticoagulant regimen. At long-term follow-up (17.7 +/- 9.4 months) cardiac mortality myocardial infarction and target-vessel revascularization rates were 0.4%, 1.5% and 9.3%, respectively. In multivessel and diabetic patients, a worse long-term event-free survival was observed. Logistic multivariate analysis revealed bailout stenting, anticoagulant therapy, implantation of stents longer than 15 mm as predictors of 30-day ischemic events. In addition, multivessel coronary artery disease and stent application with balloon size of less than 3 mm were predictive of long-term ischemic events. CONCLUSIONS: This study demonstrates that, either electively or after failure of conventional angioplasty, coronary stenting represents an effective therapy for patients with unstable angina. In the same clinical setting, combined antiplatelet therapy is associated with a lower 30-day stent thrombosis rate than anticoagulant therapy. Bailout stenting, anticoagulant therapy, implantation of stents longer than 15 mm were shown to be predictors of 30-day ischemic events, whereas multivessel coronary artery disease and stent application with small balloon size were predictive of long-term ischemic events.

Antithrombotic therapy after coronary stent placement.

Subacute stent thrombosis and hemorrhagic complications due to intensive anticoagulant therapy limit the clinical benefit of coronary stenting. Antithrombotic therapy after coronary stent placement has not been standardized yet. From January 1994 to December 1995 a total of 338 Palmaz-Schatz stents were implanted in 285 patients. Procedural success rate was 98.8%. In the initial period, after stent placement, patients were treated with acetylsalicylic acid (ASA) and warfarin (135 patients, Group A), while subsequently, according to the results of other studies, patients were treated with ASA plus ticlopidine (146 patients, Group B). Two hours after sheath removal, Group A patients were treated with intravenous heparin until therapeutic INR (2.5-3.5) was reached; warfarin was stopped 3 months later. In Group B patients 2 hours after sheath removal a treatment with subcutaneous heparin 25,000 IU/die plus ticlopidine 500 mg/die was started. Subcutaneous heparin was maintained until hospital discharge, ticlopidine was stopped after 1 month and ASA was maintained indefinitely. There were no significant differences in baseline characteristics between the two groups. Most patients had unstable angina and in the majority of cases the stent was implanted due to intimal dissection after balloon dilation. Eleven patients had subacute thrombosis of the stent (3.9%): 9 patients were in Group A (6%) and 2 patients were in Group B (1.3%; p = 0.04). Seven patients (6 in Group A, 1 in Group B) were treated with emergency coronary angioplasty and 3 (2 in Group A, 1 in Group B) with coronary bypass; nevertheless 7 patients (6 in Group A, 1 in Group B) had an acute myocardial infarction. Eight patients (6 in Group A, 2 in Group B) had major bleeding due to a large groin hematoma requiring blood transfusion or vascular surgery. In conclusion, after coronary stenting antithrombotic therapy with ASA plus ticlopidine, as compared with anticoagulant therapy, reduces the incidence of both cardiac events and hemorrhagic complications.

Coronary stenting with the half (disarticulated) Palmaz-Schatz stent: immediate results and six-month follow-up.

Coronary stenting with the half disarticulated Palmaz-Schatz stent is particularly suitable for ostial stenoses, diaphragm stenoses, stenoses distal to tortuous segments or coronary bends and localized dissections after balloon angioplasty. Nevertheless very few data regarding the half stent exist and follow-up data are nonexistent. From January of 1994 to December of 1995 a total of 207 half stents were implanted in 175 patients. Most patients had stable or unstable angina and in the majority of cases the stent was implanted due to localized dissection or to suboptimal result. The procedural success rate was 98%. After stent implantation, 82 patients were treated with acetylsalicylic acid (ASA) and oral anticoagulant (group A), whereas 93 were treated with ASA and ticlopidine (group B). Seven patients had subacute thrombosis (5, group A; 2, group B), and six patients had major bleeding (5, group A; 1, group B). Overall, patients in group A had more cardiovascular complications than patients in group B (10, group A; 3, group B; p = 0.047). After 6-mo follow-up, 1 patient had died and 27 patients had symptoms of angina (16%). Thirteen patients underwent a second PTCA (7%) and four patients (2%) were referred for coronary artery bypass. In conclusion, coronary stenting with half Palmaz-Schatz stent appears to be a safe and effective procedure. In selected cases, the half Palmaz-Schatz stent is easier to handle than the complete stent, it is associated with a low rate of clinical restenosis, and it lowers procedural costs.

Results of coronary stenting for unstable versus stable angina pectoris.

Coronary artery stenting has been shown to improve the short- and long-term results of coronary angioplasty in mainly stable patients with 1-vessel disease, but it is uncertain whether its use in an unstable clinical setting may be safe and useful. To evaluate the stenting efficacy in patients with unstable angina, we retrospectively examined our experience with the Palmaz-Schatz balloon expandable stent in 231 consecutive patients. Patients were divided into 2 groups on the basis of symptoms at the time of stent implantation: group U (132 patients) had unstable angina, and group S (99 patients) had stable angina. After stent insertion, patients were treated with anticoagulant or combined antiplatelet therapy. Baseline characteristics of the 2 groups were comparable with the exception of age (higher in the unstable group) and angiographic characteristics of the target lesions (more unfavorable in unstable patients). In both groups, coronary stenting presented a high procedural success rate. Major in-hospital complications occurred in 9 unstable (6.8%) and in 2 stable (2%) patients (p = NS) and were mainly related to subacute stent thrombosis. In both groups, subacute stent thrombosis mostly occurred in patients treated with anticoagulant therapy (7 of 9 unstable patients, 2 of 2 stable patients). At 6-month follow-up, unstable and stable patients had a similar incidence of death (0%), Q-wave myocardial infarction (0%), and need of coronary artery bypass graft (3.2% vs 4%, p = NS), but coronary angioplasty repetition (4.8% vs 14%, p = 0.027) and target vessel revascularization (6.3% vs 17%, p = 0.019) rates were lower in the unstable group. In conclusion, stent insertion increases the short- and midterm coronary angioplasty effectiveness in unstable angina, making it possible to achieve outcomes quite comparable to stable angina. Compared with conventional anticoagulant regimen, combined antiplatelet therapy after placement of coronary stents seems to reduce the incidence of subacute thrombosis also in this clinical setting.

[Implanting of coronary stents in patients with unstable angina]. / L'impianto dello stent coronarico nei pazienti con angina instabile.

In the present study, we retrospectively examined our experience with the Palmaz-Schatz stent in patients with unstable angina to determine: a) different outcomes between patients with stable and unstable angina, b) correlation between the class of unstable angina and 1-month and 6-month results, c) correlation between lesion morphology and procedural complications. From January 1994 to January 1996, 160 patients with unstable angina (Group A) and 104 with stable angina (Group B) underwent coronary stenting. According to the modified Braunwald classification patients with unstable angina were divided into four classes. Lesion morphology was classified in simple and complex. Procedural success was 98% in Group A patients and 99% in Group B patients. We observed 9 (5.6%) major complications in Group A vs 2 (1.9%) in Group B. Subacute thrombosis occurred in 9 patients in Group A and in 2 patients in Group B and these different rates were responsible for the higher number of acute myocardial infarction and urgent revascularization procedures in Group A patients. At 6-month follow-up there were no differences between Group A and Group B patients. Patients in different classes of angina showed a similar cardiac event rate at 1-month and 6-month follow-up. We found 108 complex lesions in patients with unstable angina vs 20 in patients with stable angina (p = 0.0001). Among the 9 patients with unstable angina and subacute thrombosis, 6 had a complex lesion and 3 a simple lesion (NS). In conclusion, patients with unstable angina receiving intracoronary stent have similar clinical outcome at 1-month and 6-month follow-up as compared to patients with stable angina. The class of unstable angina and the complex morphology of the lesion are not related to procedural complications.

[Endocoronary stent: its use to improve suboptimal outcome of angioplasty]. / Stent endocoronarcio: l'utilizzo per migliorare i risultati subottimali dell' angioplastica.

BACKGROUND: This single-center report describes the results of unplanned coronary stenting for the treatment of suboptimal angiographic results after conventional coronary angioplasty (PTCA), Suboptimal results of PTCA were defined as: a) residual stenosis > or = 30% with TIMI flow 3; b) presence of coronary dissection < 15 mm with TIMI flow 3. PATIENTS: From January 1994 to December 1995, 213 patients with suboptimal result of PTCA underwent coronary stent implantation. RESULTS: Stenting resulted in a technical and angiographic success in 99.5% of patients. In-hospital complications involved acute myocardial infarction (2.3%), coronary artery bypass grafting (1.4%), re-PTCA (2.3%) and vascular complications at the puncture site (1.4%). No deaths occurred. The in-hospital complication rate was similar in the groups of patients stented for coronary dissection or residual stenosis > or = 30%. Instead, the combined antiplatelet treatment group showed lower rates of subacute stent thrombosis (0.8 vs 8.9%; p = 0.011) and major complications (1.6 vs 10%; p = 0.016) than the ASA-warfarin treatment group. At a six-month follow-up, clinical restenosis was detected in 9.5% of patients. Re-PTCA was performed in 7.1% of patients and elective coronary bypass grafting in 2.8%. No acute myocardial infarction occurred and one patient presented a non-cardiovascular death. At the end of the follow-up, only 5.2% of the patient were still symptomatic. CONCLUSIONS: The unplanned use of intracoronary stenting for the treatment of suboptimal result of PTCA improves the immediate angiographic result, reducing the procedural complication rate with good short- and long-term clinical results.

[Percutaneous aortic valvuloplasty in the adult. When and why is now useful?]. / La valvuloplastica aortica percutanea nell'adulto. Quando e per chi è ancora utile?.

Percutaneous aortic valvuloplasty was introduced into clinical practice in 1986 and widely applied in elderly patients with symptomatic aortic stenosis. Nevertheless its results have been unsatisfactory over the mid to long term due to a high incidence of restenosis after 6-12 months. At the same time, patients over 70 years are more frequently undergoing surgical aortic valve replacement with low immediate postoperative mortality and good long term results. Although randomized trials are not available, aortic valve replacement seems to be a definitive therapeutic treatment when compared to the palliative result of aortic percutaneous valvuloplasty. However, since the complication rate of valvuloplasty carried out in cardiological centers with experienced personnel is low, this procedure is still indicated in selected patients. The very old (> 80 years) patients with associated systemic disease, and candidates for major surgery are referred for this procedure. Another indication for aortic valvuloplasty is severe aortic stenosis with cardiogenic shock; in this case, valve dilatation improves clinical status and acts as a "bridge" to surgery, enabling surgical intervention to be carried out at a later date. Nowadays, aortic percutaneous valvuloplasty is a possible alternative to surgical treatment in patients with an absolute surgical contraindication and in those who are in such poor clinical condition that they cannot be immediately referred to surgery. It is also useful for patients requiring urgent non-cardiac surgery (e.g., subjects with gastrointestinal bleeding). We discuss our results with this procedure which concord with those presented in the literature.

Intravascular Stenting in a Female Patient with Spontaneous Coronary Dissection and Von WillebrandÕs Disease.

We report a case of spontaneous coronary dissection occurring in a 46-year-old women affected by von WillebrandÕs disease presenting with anterior myocardial infarction. The patient was treated with thrombolytic therapy and stent implantation. We believe that in patients with single vessel spontaneous coronary dissection and unstable clinical condition, coronary stenting may provide an alternative treatment in place of coronary surgery.

[Angioplasty in patients already treated with aortocoronary bypass: immediate and short-term results]. / L'angioplastica nei pazienti già operati di bypass aortocoronarico: risultati immediati e a breve termine.

Percutaneous transluminal coronary angioplasty (PTCA) is performed in patients with prior aortocoronary bypass grafting (CABG) with good results in native vessels and in the coronary graft anastomoses, but with high percentage of restenosis in the body and in the proximal portion of the grafts. The use of intracoronary stents is now spreading, their implantation can improve the immediate outcome and may decrease the incidence of restenosis, mostly in the body of the graft. In order to evaluate PTCA in CABG patients as to numbers and short-term results, the data regarding the year 1993 of 10 Italian Centers are presented. In these Centers 3,519 PTCA were performed, 233 (6.6%) of which on CABG patients. PTCA has been performed in native vessels in 136 patients and in CABG in 126 patients, with 29 patients treated in native vessels as well as in CABG. An angiographic and clinical success was obtained in 215 patients (92%). A major complication occurred in 11 (4.7%) patients with 8 (3.4%) myocardial infarctions, and 3 (1.3%) deaths. Forty-five (19.3%) stents were implanted with considerable differences among the Centers. One hundred seventy-three patients were followed up for 6 months: 110 (63.6%) were asymptomatic and 57 (32.9%) had complained angina; 27 (15.6%) had a second PTCA and 6 (3.5%) had CABG surgery; 1 patient (0.6%) suffered a myocardial infarction and 7 (4%) died (3 due to CABG reinterventions). To evaluate the long-term follow-up, data regarding 58 patients submitted to PTCA in the Institute of Cardiology of Bologna since 1985 to 1993 are showed, with a 3-year follow-up (36 +/- 26 months).(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma fibrinogen and platelet count in stroke.

Plasma fibrinogen levels and platelet counts were evaluated in 30 patients with acute ischemic cerebral infarction (CI) three and nine days after the onset of symptoms. Hyperfibrinogenemia (379.4 +/- 80.3 vs 327.3 +/- 48.3 mg/dL of controls, p < 0.005), a reduction of platelet count (207.133 +/- 48.388 vs 288.375 +/- 61.373 x 10(9)/L of controls, p < 0.001), and an inverse correlation (r = -0.41, p < 0.05) between the two parameters were observed on day three. On day nine, platelet counts normalized while plasma fibrinogen levels slightly increased; the inverse correlation no longer occurred. The results suggest that in the earliest phase of stroke plasma fibrinogen levels may condition the extent of platelet accumulation or consumption in the ischemic area. This confirms in vivo that the platelet aggregation process is strictly dependent on fibrinogen concentration.