Antonio L. Bartorelli

Coronary artery imaging with intravascular high-frequency ultrasound.

Safe and effective clinical application of new interventional therapies may require more precise imaging of atherosclerotic coronary arteries. To determine the reliability of catheter-based intravascular ultrasound as an imaging modality, a miniaturized prototype ultrasound system (1-mm transducer; center frequency, 25 MHz) was used to acquire two-dimensional, cross-sectional images in 21 human coronary arteries from 13 patients studied at necropsy who had moderate-to-severe atherosclerosis. Fifty-four atherosclerotic sites imagined by ultrasound were compared with formalin-fixed and fresh histological sections of the coronary arteries with a digital video planimetry system. Ultrasound and histological measurements correlated significantly (all p less than 0.0001) for coronary artery cross-sectional area (r = 0.94), residual lumen cross-sectional area (r = 0.85), percent cross-sectional area (r = 0.84), and linear wall thickness (plaque and media) measured at 0 degrees, 90 degrees, 180 degrees, and 270 degrees (r = 0.92). Moreover, ultrasound accurately predicted histological plaque composition in 96% of cases. Anatomic features of the coronary arteries that were easily discernible were the lumen-plaque and media-adventitia interfaces, very bright echoes casting acoustic shadows in calcified plaques, bright and homogeneous echoes in fibrous plaques, and relatively echo-lucent images in lipid-filled lesions. These data indicate that intravascular ultrasound provides accurate image characterization of the artery lumen and wall geometry as well as the presence, distribution, and histological type of atherosclerotic plaque. Thus, ultrasound imaging appears to have great potential application for enhanced diagnosis of coronary atherosclerosis and may serve to guide new catheter-based techniques in the treatment of coronary artery disease.

Comparison of zotarolimus-eluting and everolimus-eluting coronary stents.

BACKGROUND New-generation coronary stents that release zotarolimus or everolimus have been shown to reduce the risk of restenosis. However, it is unclear whether there are differences in efficacy and safety between the two types of stents on the basis of prospectively adjudicated end points endorsed by the Food and Drug Administration. METHODS In this multicenter, noninferiority trial with minimal exclusion criteria, we randomly assigned 2292 patients to undergo treatment with coronary stents releasing either zotarolimus or everolimus. Twenty percent of patients were randomly selected for repeat angiography at 13 months. The primary end point was target-lesion failure, defined as a composite of death from cardiac causes, any myocardial infarction (not clearly attributable to a nontarget vessel), or clinically indicated target-lesion revascularization within 12 months. The secondary angiographic end point was the extent of in-stent stenosis at 13 months. RESULTS At least one off-label criterion for stent placement was present in 66% of patients. The zotarolimus-eluting stent was noninferior to the everolimus-eluting stent with respect to the primary end point, which occurred in 8.2% and 8.3% of patients, respectively (P<0.001 for noninferiority). There were no significant between-group differences in the rate of death from cardiac causes, any myocardial infarction, or revascularization. The rate of stent thrombosis was 2.3% in the zotarolimus-stent group and 1.5% in the everolimus-stent group (P=0.17). The zotarolimus-eluting stent was also noninferior regarding the degree (+/-SD) of in-stent stenosis (21.65+/-14.42% for zotarolimus vs. 19.76+/-14.64% for everolimus, P=0.04 for noninferiority). In-stent late lumen loss was 0.27+/-0.43 mm in the zotarolimus-stent group versus 0.19+/-0.40 mm in the everolimus-stent group (P=0.08). There were no significant between-group differences in the rate of adverse events. CONCLUSIONS At 13 months, the new-generation zotarolimus-eluting stent was found to be noninferior to the everolimus-eluting stent in a population of patients who had minimal exclusion criteria. (ClinicalTrials.gov number, NCT00617084.)

Percutaneous Left Atrial Appendage Transcatheter Occlusion to Prevent Stroke in High-Risk Patients With Atrial Fibrillation Early Clinical Experience

Background—Thromboembolism due to atrial fibrillation (AF) is a frequent cause of stroke. More than 90% of thrombi in AF form in the left atrial appendage (LAA). Obliteration of the appendage may prevent embolic complications. Methods and Results—We evaluated the feasibility and safety of implanting a novel device for percutaneous left atrial appendage transcatheter occlusion (PLAATO). LAA occlusion using the PLAATO system was attempted in 15 patients with chronic AF at high risk for stroke, who are poor candidates for long-term warfarin therapy. The implant consists of a self-expanding nitinol cage covered with a polymeric membrane (ePTFE). The LAA was successfully occluded in 15/15 patients (100%). Angiography and transesophageal echocardiography (TEE) during the procedure showed that the device was well-seated in all patients and that there was no evidence of perforation, device embolization, or interference with surrounding structures. In 1 patient, the first procedure was complicated by a hemopericardium, which occurred during LAA access. A second attempt 30 days later was successful with no untoward sequela. No other complications occurred. At 1-month follow-up, chest fluoroscopy and TEE revealed continued stable implant position with smooth atrial-facing surface and no evidence of thrombus. Conclusions—Thus, transcatheter closure of the LAA is feasible in humans. This novel implant technology may be appropriate for patients with AF who are not suitable candidates for anticoagulation therapy. Further trials are needed to show the long-term safety and its efficacy in reducing stroke.

Angiographic Findings of the Multicenter Randomized Study With the Sirolimus-Eluting Bx Velocity Balloon-Expandable Stent (RAVEL) Sirolimus-Eluting Stents Inhibit Restenosis Irrespective of the Vessel Size

Background—Restenosis remains the major limitation of coronary catheter-based intervention. In small vessels, the amount of neointimal tissue is disproportionately greater than the vessel caliber, resulting in higher restenosis rates. In the Randomized Study With the Sirolimus-Eluting Bx Velocity Balloon-Expandable Stent (RAVEL) trial, ≈40% of the vessels were small (<2.5 mm). The present study evaluates the relationship between angiographic outcome and vessel diameter for sirolimus-eluting stents. Methods and Results—Patients were randomized to receive either an 18-mm bare metal Bx VELOCITY (BS group, n=118), or a sirolimus-eluting Bx VELOCITY stent (SES group, n=120). Subgroups were stratified into terciles according to their reference diameter (RD; stratum I, RD <2.36 mm; stratum II, RD 2.36 mm to 2.84 mm; stratum III, RD >2.84 mm). At 6-month follow-up, the restenosis rate in the SES group was 0% in all strata (versus 35%, 26%, and 20%, respectively, in the BS group). In-stent late loss was 0.01±0.25 versus 0.80±0.43 mm in stratum I, 0.01±0.38 versus 0.88±0.57 mm in stratum II, and −0.06±0.35 versus 0.74±0.57 mm in stratum III (SES versus BS). In SES, the minimal lumen diameter (MLD) remained unchanged (&Dgr; −0.72 to 0.72 mm) in 97% of the lesions and increased (=late gain, &Dgr;MLD <−0.72 mm) in 3% of the lesions. Multivariate predictors for late loss were treatment allocation (P <0.001) and postprocedural MLD (P = 0.008). Conclusions—Sirolimus-eluting stents prevent neointimal proliferation and late lumen loss irrespective of the vessel diameter. The classic inverse relationship between vessel diameter and restenosis rate was seen in the bare stent group but not in the sirolimus-eluting stent group.

Maintenance of Long-Term Clinical Benefit With Sirolimus-Eluting Coronary Stents Three-Year Results of the RAVEL Trial

Background—The use of sirolimus-eluting coronary stents has been associated with a nearly complete elimination of restenosis at 6 months and with a very low 1-year incidence of major adverse cardiac events (MACE). This analysis examined whether these beneficial effects persist over the longer term. Methods and Results—This multicenter trial randomly assigned 238 patients to revascularization of single, de novo, native coronary artery lesions with sirolimus-eluting versus conventional bare-metal stents. Survival free from target lesion revascularization (TLR), target vessel failure (TVF), and MACE up to 3 years of follow-up was compared between the 2 treatment groups. Complete data sets were available in 94.2% of patients treated with sirolimus-eluting stents and in 94.1% of patients randomized to the control group. The cumulative 1-, 2-, and 3-year event-free survival rates were 99.2%, 96.5%, and 93.7% for TLR and 95.8%, 92.3%, and 87.9% for TVF, respectively, in the sirolimus-eluting stent group, versus 75.9%, 75.9%, and 75.0% for TLR and 71.2%, 69.4%, and 67.3% for TVF in the control group (P<0.001 for both comparisons at 3 years). Rates of MACE at 3 years were 15.8% in patients randomly assigned to sirolimus-eluting stents versus 33.1% in patients assigned to bare-metal stents (P=0.002). One patient treated with a sirolimus-eluting stent died of a cardiac cause between 12 and 36 months. Conclusions—Treatment of de novo coronary stenosis with sirolimus-eluting stents was associated with a sustained clinical benefit and very low rates of TLR and of other MACE up to 3 years after device implantation.

Contrast volume during primary percutaneous coronary intervention and subsequent contrast-induced nephropathy and mortality

Context Contrast-induced nephropathy (CIN) can complicate percutaneous coronary intervention (PCI). A better understanding of the relationship among contrast volume, patient characteristics, and CIN could help to reduce this complication. Contribution Of 561 patients who underwent primary PCI in the setting of ST-segment elevation myocardial infarction, 20% developed CIN, and those with CIN were more likely than those without CIN to die in hospital. Higher contrast volume and contrast ratio (volume administered/volume calculated) were associated with CIN and in-hospital death. Caution It is unclear whether the worse outcomes were due to the contrast or whether unmeasured aspects of disease severity led to both the need for more contrast and the worse outcomes. The Editors Primary percutaneous coronary intervention (PCI), defined as intervention in the culprit vessel within 12 hours after the onset of chest pain without previous thrombolytic or other clot-dissolving therapy, is the best available strategy for treatment of ST-segment elevation acute myocardial infarction (STEMI) (1). Patients having primary PCI, however, are at higher risk for contrast-induced nephropathy (CIN), although most of them do not have preprocedural renal dysfunction (2). Contrast-induced nephropathy is associated with a marked increase in in-hospital morbidity and mortality rates, which may partially thwart the survival benefit of primary PCI in patients who develop this serious renal complication (2, 3). Effective CIN prevention may further improve the clinical outcome of patients with STEMI who receive primary PCI. Potential preventive strategies include protecting the kidney from contrast- or ischemic-induced injury and limiting the amount of contrast administered. Studies of the antioxidant agent N-acetylcysteine (4) have yielded promising results for kidney protection. N-acetylcysteine has been shown to be effective in reducing CIN incidence and in improving clinical outcomes after emergency or primary PCI, particularly when administered as a high-dose intravenous bolus or with sodium bicarbonate (4, 5). Conversely, because few previous studies have reported the amount of contrast used, data on the effect of contrast volume limitation during primary PCI are lacking. Moreover, investigators disagree on the relation between the volume of contrast administered during interventional procedures and the risk for CIN. Some studies have reported no relationship, whereas others have suggested an independent correlation (614). ST-segment elevation myocardial infarction further complicates the issue. Patients with STEMI who are not undergoing primary PCI may also have acute worsening of renal function with the same prognostic implications as for CIN (15), which suggests that acute kidney injury may result from hemodynamic compromise rather than from CIN per se. In addition, primary PCI success, a major determinant of clinical outcome in patients with STEMI (1618), may require larger amounts of contrast. Thus, an optimal procedural result should be carefully weighed against risk for CIN. The association of contrast volume, as an absolute and a weight- and creatinine-adjusted value (19); CIN incidence; and clinical outcome in the setting of primary PCI remains unknown. As a result, evidence-based recommendations to guide best procedural strategies during primary PCI are still lacking. We sought to prospectively assess the possible association between contrast volume and CIN incidence and in-hospital clinical outcome in patients with STEMI who undergo primary PCI. Methods Study Population We conducted our prospective observational study at the Centro Cardiologico Monzino, University of Milan, between 1 January 2002 and 30 September 2007. We enrolled all consecutive patients with STEMI who were undergoing primary PCI. According to our institute protocol, we included patients who presented within 12 hours (18 hours for STEMI complicated by cardiogenic shock) of the onset of symptoms (characteristic pain lasting for at least 30 minutes, not responsive to nitrates, with electrocardiographic ST-segment elevation of at least 0.2 mV in 2 or more contiguous leads, or left bundle-branch block). We excluded patients receiving long-term peritoneal or hemodialysis treatment. We also excluded patients if they had cardiac surgery for emergency coronary revascularization or STEMI-related mechanical complications, died during PCI, or had been treated with an intravenous bolus of N-acetylcysteine before PCI. The Ethics Committee of the Centro Cardiologico Monzino approved the study, and all patients gave written, informed consent. PCI Procedure A 24-hour on-call interventional team performed primary PCI according to standard clinical practice by using standard guide catheters (6 French), guide wires, and balloon catheters via the femoral approach. Patients received a 5000-U bolus of heparin, followed by additional boluses during the procedure to maintain an activated clotting time longer than 300 seconds (between 200 and 250 seconds when abciximab was used). Coronary stenting was performed with standard technique. Contrast dose was left to the discretion of the interventional cardiologist. All patients received nonionic, low-osmolar contrast agents (iomeprol or iohexol). After contrast exposure, patients received isotonic (0.9%) saline intravenously at a rate of 1 mL/kg per hour for 12 hours. In patients with a left ventricular ejection fraction (LVEF) lower than 40% or overt heart failure, the hydration rate was reduced to 0.5 mL/kg per hour. Poststenting antithrombotic treatment consisted of aspirin and either clopidogrel or ticlopidine at standard dosages. Data Collection We measured serum creatinine concentration in all patients at hospital admission (before primary PCI), every day for the following 3 days, at discharge from the coronary care unit, and at hospital discharge. We estimated creatinine clearance by applying the CockcroftGault formula to the serum creatinine concentration (20). We defined preprocedural renal insufficiency as a creatinine clearance less than 1 mL/s (60 mL/min) (21). We calculated the maximum contrast dose (MCD) for each patient by using the formula proposed by Cigarroa and colleagues (19): MCD (mL) = (5body weight [kg]) divided by serum creatinine (mg/dL). From this contrast limit, we determined the contrast ratio by dividing the administered contrast amount by the calculated MCD. We left the use of -adrenergic blocking agents, angiotensin-converting enzyme inhibitors, platelet glycoprotein IIb/IIIa receptor inhibitors (abciximab), diuretics, intra-aortic balloon pump, or inotropic drug support to the discretion of the interventional and coronary care unit cardiologists, on the basis of the current standards of care recommended by published guidelines (22). During hospitalization, medications were changed as needed at the discretion of the cardiologist responsible for the patient. The primary end point of the study was the occurrence of CIN, defined as a greater than 25% increase in creatinine concentration from the baseline value in the 72 hours after primary PCI (23). In-hospital mortality rate and other major adverse clinical events were also evaluated as secondary end points. Statistical Analysis On the basis of our previous study (2), we calculated a sample size of 550 patients, assuming a 30% incidence of patients exceeding the MCD and a 10% incidence of CIN in patients with a contrast ratio less than 1. This sample size allowed 84% statistical power to assess a significantly higher ( error of 0.05) CIN incidence of 20% (odds ratio, 2) in the group with a contrast ratio greater than 1. We present continuous variables as means (SDs); we compared them by using the t test for independent samples or one-way analysis of variance, as appropriate. We compared categorical data by using the chi-square test or the Fisher exact test, as appropriate. The P values reported in Table 1 were not adjusted for multiple comparisons. Table 1. Patient and Procedure Characteristics We explored the relationship between contrast ratio and maximum percentage increase in creatinine concentration after primary PCI by using linear regression analysis. Both variables were log-transformed before analysis. We estimated predicted probabilities of CIN and mortality from the logistic models with the covariates set to the population average values. We assessed the association among contrast volume, contrast ratio, and clinical outcomes (CIN and in-hospital mortality) through logistic regression analysis. First, we included only contrast volume or contrast ratio (model 1). To adjust for potential confounders selected among recognized clinical predictors of the 2 outcomes (age, body weight, infarct location, LVEF, time to reperfusion, and baseline creatinine level), we developed 2 multivariable logistic regression models: model 2, which adjusted for the 2 major predictors (LVEF and creatinine level), and model 3, which adjusted for the 6 considered variables. Because contrast ratio is a calculated variable that includes both body weight and creatinine, we did not include those 2 variables in the models when we tested the association with contrast ratio. Thus, model 2 included LVEF and time to reperfusion, whereas model 3 included age, infarction location, LVEF, and time to reperfusion. Because of the relatively small number of events, we only considered mortality models with 2 or fewer covariates. To assess whether the effect of contrast volume on CIN differed in patients with renal insufficiency, we stratified our sample according to creatinine clearance (1 or <1 mL/s [60 or <60 mL/min]) and tested the appropriate interaction terms by using logistic regression, adjusting with model 2. All tests were 2-sided. We performed all calculations by using SAS, version 9.13 (SAS Institute, Cary, North Carolina). Role of the Funding Source The Centro Cardiologico Monz

Randomized evaluation of polytetrafluoroethylene-covered stent in saphenous vein grafts: the Randomized Evaluation of polytetrafluoroethylene COVERed stent in Saphenous vein grafts (RECOVERS) Trial.

Background Treatment of lesions located in saphenous vein grafts (SVGs) is associated with increased procedural risk and a high rate of restenosis. Methods and Results We conducted a randomized, multicenter trial to evaluate the usefulness of a polytetrafluoroethylene (PTFE)‐covered stent compared with a bare stainless steel (SS) stent for prevention of restenosis and major adverse cardiac events (MACE) in patients undergoing SVG treatment. The primary end point was angiographic restenosis at 6 months. Secondary end points were 30‐day and 6‐month MACE rates, defined as the cumulative of death, myocardial infarction (MI), and target lesion revascularization. Between September 1999 and January 2002, 301 patients with SVG lesions were randomized to either the PTFE‐covered JoStent coronary stent graft (PTFE group, n=156) or the SS JoFlex stent (control group, n=145). Angiographic and procedural success rates were similar between the 2 groups (97.4% versus 97.9% and 87.3% versus 93.8%, respectively). The incidence of 30‐day MACE was higher in the PTFE group (10.9% versus 4.1%, P=0.047) and was mainly attributed to MI (10.3% versus 3.4%, P=0.037). The primary end point, the restenosis rate at 6‐month follow‐up, was similar between the 2 groups (24.2% versus 24.8%, P=0.237). Although the 6‐month non‐Q‐wave MI rate was higher in the PTFE group (12.8% versus 4.1%, P=0.013), the cumulative MACE rate was not different (23.1% versus 15.9%, P=0.153). Conclusions The study did not demonstrate a difference in restenosis rate and 6‐month clinical outcome between the PTFE‐covered stent and the SS stent for treatment of SVG lesions. However, a higher incidence of nonfatal myocardial infarctions was found in patients treated with the PTFE‐covered stent. (Circulation. 2003;108:37‐42.)

Short- and long-term efficacy of a calcium-antagonistic agent (nifedipine) combined with methyldopa in the treatment of severe hypertension.

Nifedipine induces a potent vasodilating and antihypertensive effect in man through a calciumantagonistic action. The drug was tested alone and in combination with methyidopa in 23 subjects with uncomplicated primary severe hypertension (diastolic pressure > 120 mm Hg) in a short- and long-term therapeutic trial. Hourly pressure readings during the short-term period showed that the antihypertensive response to nifedipine (10 mg orally) is maximal within 40 minutes and lasts for 8-12 hours. When nifedipine is administered every 6 hours the tendency of blood pressure to rise after each dose is repressed by the next dose, so that pressure remains significantly reduced throughout the 24 hours; when methyidopa is combined (250 mg four times daily) blood pressure is further reduced toward normal, without significant fluctuations during the day. After 10 days of drug combination, the antihypertensive response was mediated through reduction of peripheral vascular resistance associated with increase in cardiac output. Renal function was unchanged or improved and sodium retention and plasma volume expansion were not promoted. In six patients with very severe hypertension (diastolic pressure > 140 mm Hg) complicated by cardiac failure, a dosing regimen every 4 hours of the two compounds promptly relieved dyspnea and lung congestion and, within 2-3 days, stabilized blood pressure to an average of 150/98 mm Hg. Persistence of the antihypertensive efficacy of this drug combination in a dosing regimen every 6 hours and its beneficial effects on heart size, ECG and fundi were documented in 22 subjects (four of whom belonged to the decompensated group) who completed a 12-month follow-up. A tendency in seven cases to ankle pitting or edema was the major side effect of nifedipine; the cause of this effect remains obscure.

Microembolization during carotid artery stenting in patients with high-risk, lipid-rich plaque: A randomized trial of proximal versus distal cerebral protection

OBJECTIVES The goal of this study was to compare the rate of cerebral microembolization during carotid artery stenting (CAS) with proximal versus distal cerebral protection in patients with high-risk, lipid-rich plaque. BACKGROUND Cerebral protection with filters partially reduces the cerebral embolization rate during CAS. Proximal protection has been introduced to further decrease embolization risk. METHODS Fifty-three consecutive patients with carotid artery stenosis and lipid-rich plaque were randomized to undergo CAS with proximal protection (MO.MA system, n = 26) or distal protection with a filter (FilterWire EZ, n = 27). Microembolic signals (MES) were assessed by using transcranial Doppler during: 1) lesion wiring; 2) pre-dilation; 3) stent crossing; 4) stent deployment; 5) stent dilation; and 6) device retrieval/deflation. Diffusion-weighted magnetic resonance imaging was conducted before CAS, after 48 h, and after 30 days. RESULTS Patients in the MO.MA group had higher percentage diameter stenosis (89 ± 6% vs. 86 ± 5%, p = 0.027) and rate of ulcerated plaque (35% vs. 7.4%; p = 0.019). Compared with use of the FilterWire EZ, MO.MA significantly reduced mean MES counts (p < 0.0001) during lesion crossing (mean 18 [interquartile range (IQR): 11 to 30] vs. 2 [IQR: 0 to 4]), stent crossing (23 [IQR: 11 to 34] vs. 0 [IQR: 0 to 1]), stent deployment (30 [IQR: 9 to 35] vs. 0 [IQR: 0 to 1]), stent dilation (16 [IQR: 8 to 30] vs. 0 [IQR: 0 to 1]), and total MES (93 [IQR: 59 to 136] vs. 16 [IQR: 7 to 36]). The number of patients with MES was higher with the FilterWire EZ versus MO.MA in phases 3 to 5 (100% vs. 27%; p < 0.0001). By multivariate analysis, the type of brain protection was the only independent predictor of total MES number. No significant difference was found in the number of patients with new post-CAS embolic lesion in the MO.MA group (2 of 14, 14%) as compared with the FilterWire EZ group (9 of 21, 42.8%). CONCLUSIONS In patients with high-risk, lipid-rich plaque undergoing CAS, MO.MA led to significantly lower microembolization as assessed by using MES counts.

PLAATO (Percutaneous Left Atrial Appendage Transcatheter Occlusion) for prevention of cardioembolic stroke in non-anticoagulation eligible atrial fibrillation patients: results from the European PLAATO study

The European PLAATO (Percutaneous Left Atrial Appendage Transcatheter Occlusion) study was performed to determine the safety and efficacy of left atrial appendage occlusion by catheter technique. Embolic stroke due to atrial fibrillation is a common observation, especially in the elderly. Most thrombi in atrial fibrillation form in the left atrial appendage (LAA), its occlusion may therefore reduce the incidence of stroke in these patients.