C Stratos

National and Kapodistrian University of Athens, Athens, Attiki, Greece

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Publications (46)218.69 Total impact

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    ABSTRACT: Retrograde nontransseptal balloon mitral valvuloplasty (RNBMV) is a transarterial technique of mitral valvuloplasty, developed with the aim to avoid complications associated with transseptal catheterization. Between April 1988 and December 1999, RNBMV has been attempted in 393 patients with symptomatic mitral stenosis (aged 44 ± 11 years, 322 women, mean echocardiographic score 7.7 ± 1.9) at the University of Athens, Greece. The procedure was completed in 392 cases. Technical success (gain in mitral valve area ≥ 50% with final mitral valve area ≥ 1.5 cm2, and absence of postprocedural mitral regurgitation grade > 2+) was achieved in 344 (87.5%) patients. Unfavorable predictors for immediate outcome included the echocardiographic score (P < 0.001). male gender (P = 0.005), and preprocedural mitral regurgitation (P = 0.003). Complications included death (0.3%), severe mitral regurgitation (3.1%), and femoral artery injury (0.8%). No cases of cardiac peqoration or tamponade have occurred with RNBMV. Patients with a successful immediate outcome were followed clinically for 4.8 ± 2.8 years (maximum 12 years). Event-free (freedom from cardiac death, mitral valve replacement, redo valvuloplasty, and recurrence of NYHA Class > II) survival rates at 1, 2, 5, and 12 years post-RNBMV were 99.7 ± 0.3%, 96.1 ± 1.1%, 84.7 ± 2.2%. and 67.6 ± 4.8%, respectively. The echocardiographic score (P < 0.001) and the postprocedural mitral valve area (P < 0.001) were significant independent predictors of long-term outcome following RNBMV. Experience with RNBMV has fulfilled expectations regarding lowering of the risk of occurrence of specific cardiac complications encountered during mitral valvuloplasty, and reveals this approach as a safe and efficient alternative to the more commonly used antegrade technique.
    Journal of Interventional Cardiology 06/2007; 13(4):269 - 280. · 1.50 Impact Factor
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    ABSTRACT: Background: Moderate alcohol consumption has been associated with lower cardiovascular risk. The effect of alcohol on vascular reactivity has not been adequately investigated.Methods: We studied 12 healthy volunteers (< 40 years of age) without known cardiovascular risk factors. The subjects were studied on 2 separate occasions, one with alcohol (one ounce orally, dose corresponding to 2 ‘drink equivalents’) and one with placebo according to a randomized, double-blind crossover, fashion. High-frequency ultrasound of the brachial artery was used to study endothelial function after reactive hyperemia induced by cuff occlusion before and 30 minutes after drinking.Results: There was a significant dilatation of the brachial artery (P
    American Journal of Hypertension - AMER J HYPERTENS. 01/2002; 15(4).
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    ABSTRACT: We investigated the midterm clinical significance of human coronary atherosclerotic plaques temperature after a successful percutaneous coronary intervention. Previous studies have shown an increased temperature in human atherosclerotic plaques. However, the prognostic significance of atherosclerotic plaque temperature in patients undergoing a successful percutaneous intervention is unknown. We prospectively investigated the relation between the temperature difference (deltaT) between the atherosclerotic plaque and the healthy vessel wall and event-free survival among 86 patients undergoing a successful percutaneous intervention. Temperature was measured by a thermography catheter, as previously validated. The study group consisted of patients with effort angina (EA) (34.5%), unstable angina (UA) (34.5%) and acute myocardial infarction (AMI) (30%). The deltaT increased progressively from EA to AMI (0.132 +/- 0.18 degrees C in EA, 0.637 +/- 0.26 degrees C in UA and 0.942 +/- 0.58 degrees C in AMI). The median clinical follow-up period was 17.88 +/- 7.16 months. The deltaT was greater in patients with adverse cardiac events than in patients without events (deltaT: 0.939 +/- 0.49 degrees C vs. 0.428 +/- 0.42 degrees C; p < 0.0001). The deltaT was a strong predictor of adverse cardiac events during the follow-up period (odds ratio 2.14, p = 0.043). The threshold of the deltaT value, above which the risk for an adverse cardiac event was significantly increased, was 0.5 degrees C. The incidence of adverse cardiac events in patients with deltaT > or = 0.5 degrees C was 41%, as compared with 7% in patients with deltaT < 0.5 degrees C (p < 0.001). Increased local temperature in atherosclerotic plaques is a strong predictor of an unfavorable clinical outcome in patients with coronary artery disease undergoing percutaneous interventions.
    Journal of the American College of Cardiology 04/2001; 37(5):1277-83. · 14.09 Impact Factor
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    ABSTRACT: The mechanism of aortic pulse pressure decline induced by acute rapid ventricular pacing remains incompletely understood. It has been ascribed to changes in stroke volume or aortic compliance. This becomes more complicated by the dependence of aortic compliance on the level of the mean aortic pressure as well as the aortic wall properties. To test the role of such mechanical factors, aortic pressure-diameter hemodynamics, derived from simultaneous tip-micromanometer aortic pressure recordings and high-fidelity ultrasonic intravascular aortic diameter recordings, were measured in 15 normal subjects during and after abrupt cessation of rapid ventricular pacing (up to 160 bpm). Immediately after terminating the pacing, diastolic aortic pressure declined (–9%, from 87.41.2 to 79.51.7 mmHg,PPPb=EbDa, where Eb was the instantaneous aortic elastance of the paced beat and Da was the aortic diameter for the postpaced beat. The corrected pressure difference was then calculated by the following: Pcor=(DaEb)–Pa. It was found that systolic Pcor was 25% of systolic Praw and diastolic Pcor was 89% of diastolic Praw. Praw was the pressure difference between paced and spontaneous beat measured from the raw data. Pcor indicates the portion of Praw that results from a change in aortic stiffness as a consequence of viscous behavior or aorto-ventricular coupling. These data indicate that the majority of diastolic pressure decline after pacing was terminated, may reflect a change in aortic stiffness while the majority of systolic pressure rise, and may be attributable to differences in hemodynamics alone.
    International Journal of Angiology 11/2000; 9(1):34-38.
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    ABSTRACT: Retrograde nontransseptal balloon mitral valvuloplasty is a purely transarterial technique for percutaneous treatment of mitral stenosis. We report the first use of this technique via the brachial artery for a patient with aortoiliac atherosclerosis, and we comment on the difficulties and perspectives of this approach.
    Catheterization and Cardiovascular Interventions 10/2000; 51(1):101-6. · 2.51 Impact Factor
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    ABSTRACT: Aortic elasticity is an important determinant of left ventricular performance and coronary blood flow. Moreover, it has been shown that aortic elastic properties deteriorate in patients with coronary artery disease. However, the predictive role of aortic elasticity in the occurrence of coronary events, has not been addressed so far. Therefore, we set out to test prospectively the hypothesis that invasive as well as non-invasive measures of aortic elastic properties, assessed at rest from pressure-diameter relationships, could predict the development of recurrent coronary events. Clinical variables and measures of aortic function were assessed in 54 normotensive patients with coronary artery disease. The aortic pressure-diameter relationship was derived invasively with a high-fidelity Y shaped catheter (developed in our Institution) for aortic diameter measurements, simultaneously with a Millar catheter for aortic pressure measurements. Aortic root distensibility was assessed by non-invasive techniques. During an average of 3 years follow-up, 12 of 54 patients either developed unstable angina (n=8) or acute myocardial infarction (n=4). By multivariate Cox model analysis, aortic stiffness was the strongest predictor of progression to any end-point (relative risk: 3.24, CI: 1.79 to 5.83;P=0.000). When aortic stiffness was not considered, aortic distensibility was the only independent predictor for acute coronary syndromes (relative risk: 0.37 CI: 0.21 to 0.65;P=0.000). In patients with coronary artery disease, aortic elastic properties are powerful and independent risk factors for recurrent acute coronary events.
    European Heart Journal 04/2000; 21(5):390-6. · 14.10 Impact Factor
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    ABSTRACT: Previous experimental studies with a new covered stent, the autologous venous graft-covered stent (AVGCS), have shown favorable results. The aim of this study was to evaluate the feasibility and safety of this new technique in human coronary arteries and to compare the long-term outcome with uncovered stents. A venous graft was removed from an upper limb. A conventional stent then was covered by the venous graft. Fifty-eight AVGCS were implanted in 56 patients, including 16 patients with acute coronary syndromes (ACS). Additionally, in 114 patients, 138 uncovered stents were implanted, serving as a control group, including 38 patients with ACS. The procedure was successful in all patients. Stent thrombosis was observed in 3 patients in the control group and in 1 patient with an AVGCS. There was a trend for the minimal luminal diameter to be greater in the AVGCS group at follow-up (P =.07), and statistical significance was observed in patients with ACS (P <.01). The target vessel revascularization and the restenosis rates were similar between the 2 groups. In patients with ACS, the restenosis rate was less (P <.04) and there was a trend for target vessel revascularization to be less in covered stents (P =.09). The event-free survival rate at 4 years was 85% in the AVGCS group versus 81% in the control group (P = not significant); in ACS it was 94% versus 78%, respectively (P = not significant). Stents covered by thicker venous grafts were associated with improved clinical outcome. Stents covered by autologous venous grafts may be safely prepared without complications. This technique may prove to be a useful means, especially in patients with ACS.
    American Heart Journal 03/2000; 139(3):437-45. · 4.50 Impact Factor
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    ABSTRACT: The mechanism of aortic pulse pressure decline induced by acute rapid ventricular pacing remains incompletely understood. It has been ascribed to changes in stroke volume or aortic compliance. This becomes more complicated by the dependence of aortic compliance on the level of the mean aortic pressure as well as the aortic wall properties. To test the role of such mechanical factors, aortic pressure-diameter hemodynamics, derived from simultaneous tip-micromanometer aortic pressure recordings and high-fidelity ultrasonic intravascular aortic diameter recordings, were measured in 15 normal subjects during and after abrupt cessation of rapid ventricular pacing (up to 160 bpm). Immediately after terminating the pacing, diastolic aortic pressure declined (-9%, from 87.4 +/- 1.2 to 79.5 +/- 1.7 mmHg, P < 0.0001) while systolic aortic pressure increased (+19%, from 109.5 +/- 1.6 to 130.1 +/- 2.8 mmHg, P < 0.0001). Thus, pulse pressure increased from 22.1 +/- 2.2 to 50.6 +/- 3.1 mmHg, P < 0.0001. To quantify systolic and diastolic aortic pressure differences we compared the first postpaced beat (a) and the last paced beat (b). To estimate what the aortic pressure would have been for the paced beats had the aortic diameter differences due to the different heart rate not occurred we calculated the theoretical pressure of the paced beat P(b) = E(b). D(a), where E(b) was the instantaneous aortic elastance of the paced beat and D(a) was the aortic diameter for the postpaced beat. The corrected pressure difference was then calculated by the following: DeltaP(cor) = (D(a). E(b)) - P(a). It was found that systolic DeltaP(cor) was 25% of systolic DeltaP(raw) and diastolic DeltaP(cor) was 89% of diastolic DeltaP(raw). DeltaP(raw) was the pressure difference between paced and spontaneous beat measured from the raw data. DeltaP(cor) indicates the portion of DeltaP(raw) that results from a change in aortic stiffness as a consequence of viscous behavior or aorto-ventricular coupling. These data indicate that the majority of diastolic pressure decline after pacing was terminated, may reflect a change in aortic stiffness while the majority of systolic pressure rise, and may be attributable to differences in hemodynamics alone.
    International Journal of Angiology 02/2000; 9(1):34-38.
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    ABSTRACT: A renewed interest in radial artery conduits for bypass surgery has emerged during the last few years. In order to combine a surgical with a percutaneous technique, stents were covered by radial arterial grafts. The purpose of this study was to evaluate the feasibility of, and the immediate and long-term results after, intracoronary implantation of stents covered by autologous arterial grafts. A graft was removed from the radial artery. A conventional stent was then covered by the arterial graft. The autologous arterial graft was stabilized on the stent by sutures. Fifteen covered stents were implanted in 15 patients (56.1 +/- 17.3 years old) in all coronary vessels. The procedure of stent covering was feasible and short in duration. Procedural success was 100% with no in-hospital stent thrombosis, Q-wave myocardial infarction or death. In 14 patients (93.3%), including the patients with clinical restenosis, a repeat angiography was performed (minimum lumen diameter immediately after procedure: 3.01 +/- 0.22 mm, at follow-up: 2.56 +/- 0.90 mm). Target lesion revascularization was required in 2 patients. The event-free survival rate at 2 years was 87%. Intracoronary implantation of stents covered by an autologous arterial graft may be performed safely with excellent long-term results. A multicenter study is required to assess the efficacy.
    The Journal of invasive cardiology 02/2000; 12(1):7-12. · 1.57 Impact Factor
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    ABSTRACT: The physiologic basis for the hemodynamic and clinical improvement achieved by the use of intra-aortic balloon pumping in patients with cardiogenic shock has not been clarified in all its aspects. This study evaluated the possible contribution of pump-induced alterations of aortic mechanics to the overall benefit gained by the implementation of this therapeutic modality in patients with acute heart failure of ischemic origin. The aortic pressure-diameter relation was obtained by use of an intravascular catheter for aortic diameter measurements developed in our institution and previously validated, simultaneously with a catheter-tip micromanometer for aortic pressure measurements at the same aortic level. Aortic function indices were compared before and during intra-aortic balloon pumping in 12 patients with cardiogenic shock. Intra-aortic balloon pumping increased cardiac index and aortic distensibility by 24% and 30%, respectively, and reduced myocardial oxygen demand by 31% (P <.001 for all alterations). Energy loss caused by aortic wall viscosity increased by 207% (P <. 001). The aortic diameter augmentation index increased by 68% (P <. 001); the aortic pressure augmentation index decreased by 117% (P <. 001). Linear regression analysis showed that cardiac index and myocardial oxygen demand were related with the aortic stiffness constant both before and during intra-aortic balloon pumping. During intra-aortic balloon pumping, aortic distensibility was improved, and wave reflection from the arterial periphery was reduced. The relationship between cardiac index and myocardial oxygen demand and aortic stiffness suggests that improvement of the elastic properties of the aorta was an important mechanism by which intra-aortic balloon pumping improved circulatory function.
    Journal of Thoracic and Cardiovascular Surgery 01/1999; 116(6):1052-9. · 3.53 Impact Factor
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    ABSTRACT: Our aim was to present the immediate and intermediate long-term results of the application of retrograde nontransseptal balloon mitral valvuloplasty (RNBMV) in four cooperating centers from Greece and India. RNBMV is a purely transarterial method of balloon valvuloplasty, developed with the aim to avoid complications associated with transseptal catheterization. Only single-center experience with RNBMV has been previously reported. The procedure was attempted in 441 patients with symptomatic mitral stenosis (320 women, 121 men, mean age [+/-SD] 44+/-11 years, mean echocardiographic score [+/-SD] 7.7+/-2.0) from 1988 to 1996. Three hundred eighty-five patients with successful immediate outcome were followed clinically for a mean [+/-SD] of 3.5+/-1.9 (range, 0.5-9.1) years. A technically successful procedure was achieved in 388 (88%) cases. The echocardiographic score (p < 0.001), male gender (p=0.005), preprocedural mitral regurgitation (p=0.007) and previous surgical commissurotomy (p=0.029) were unfavorable predictors of immediate outcome. Complications included death (0.2%), severe mitral regurgitation (3.4%) and injury of the femoral artery (1.1%). Event-free (freedom from cardiac death, mitral valve surgery, repeat valvuloplasty and NYHA class > II symptoms) survival rates (+/-SEM) were 100%, 96.9+/-0.9%, 89.8+/-1.9% and 75.5+/-5.5% at 1, 2, 4 and 9 years, respectively. The echocardiographic score (p < 0.001), NYHA class (p=0.008) and postprocedural mitral valve area (p=0.009) were significant independent predictors of intermediate long-term outcome. Multicenter experience indicates that RNBMV is a safe and effective technique for the treatment of symptomatic mitral stenosis. As with the transseptal approach, patients with favorable mitral valve anatomy derive the greatest immediate and intermediate long-term benefit from this procedure.
    Journal of the American College of Cardiology 10/1998; 32(4):1009-16. · 14.09 Impact Factor
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    ABSTRACT: Pulmonary balloon valvuloplasty results in improvement in the right coronary artery blood flow velocity pattern and the volumetric flow in patients with pulmonary valve stenosis. These changes are closely related to concomitant changes in right ventricular systolic pressure.
    The American Journal of Cardiology 10/1998; 82(5):692-6, A9. · 3.21 Impact Factor
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    ABSTRACT: This study sought to investigate the changes induced on the pressure-area relation of the left atrium in patients with mitral stenosis after percutaneous balloon mitral valvuloplasty. Left atrial (LA) function is influenced by changes in LA afterload. The latter is increased in mitral stenosis as a result of increased resistance to blood flow imposed by the stenotic mitral valve. We studied the effects of acute alterations of LA afterload induced by retrograde nontransseptal balloon mitral valvuloplasty (RNBMV) on LA function in patients with mitral stenosis. LA pressure-area relations were obtained in 15 patients with mitral stenosis (8 with sinus rhythm, 7 with atrial fibrillation) before and after valvuloplasty, as well as in 15 normal subjects. LA pressure was recorded by a catheter-tipped micromanometer introduced retrogradely into the left atrium while LA area was recorded simultaneously using acoustic quantification. The areas of the A and V loops of the pressure-area relation as well as the LA chamber stiffness constant were calculated. Balloon valvuloplasty resulted in a significant increase in mitral valve area (p < 0.001) and a substantial reduction of the mean transmitral pressure gradient (p < 0.001) and mean LA pressure (p < 0.001). The area of the A loop in patients with sinus rhythm and the area of the V loop in those with atrial fibrillation increased significantly after completion of the procedure (p < 0.001). Furthermore, LA stiffness decreased in both groups. After RNBMV, there is a significant increase in LA pump function in patients with sinus rhythm, a significant increase in LA reservoir function in patients with atrial fibrillation and a significant reduction in LA stiffness in all patients. Marked alterations of the configuration of the LA pressure-area relation occur immediately after successful RNBMV in patients with mitral stenosis.
    Journal of the American College of Cardiology 08/1998; 32(1):159-68. · 14.09 Impact Factor
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    ABSTRACT: This is the first report of a total reconstruction of a diseased saphenous vein graft, with thrombus-containing lesion and multiple stenoses, by the implantation of arterial graft- and venous graft-coated stents, and of conventional stents. The procedure was successful without any complications, and follow-up angiography after 6 months revealed patency of the vessel.
    Catheterization and Cardiovascular Diagnosis 03/1998; 43(3):318-21.
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    ABSTRACT: This study sought to validate and apply a new method for obtaining the left atrial (LA) pressure-area relation. In physiologic investigations, the pressure-area relation is the most accurate and representative index of LA hemodynamic status. We applied real-time two-dimensional echocardiographic imaging with automatic boundary detection to estimate LA area changes. To obtain LA pressure, a catheter-tipped micromanometer was introduced retrogradely into the left atrium using a steerable cardiac catheter developed at our institution. Twenty-five patients (11 normal subjects, 7 patients with an enlarged left atrium due to heart failure, 7 patients with atrial fibrillation) were studied before and after dobutamine administration. From the LA pressure-area relation, the area of the A loop (the first counterclockwise loop) and the V loop (the second clockwise loop), the pressure-minimal area relation and the LA passive elastic chamber stiffness constant were measured. Normalized pressure-minimal area relation was highly linear and sensitive to changes in inotropic state (normal subjects: from 0.96 to 1.27 mm Hg/cm2, p < 0.01; patients with heart failure: from 0.59 to 0.68 mm Hg/cm2, p = NS; patients with atrial fibrillation: from 0.80 to 1.06 mm Hg/cm2, p < 0.05). The LA stroke work index was accurately calculated, and a very good correlation was found with LA preload. LA stroke work index was lower in patients with heart failure (3.9 +/- 0.8 cm2 x mm Hg, p < 0.001), whereas the LA stiffness constant was increased in patients with heart failure (0.801 +/- 0.097 cm(-2), p < 0.01) and atrial fibrillation (0.796 +/- 0.091 cm(-2), p < 0.01) compared with normal subjects (stroke work index 7.3 +/- 1.9 cm2 x mm Hg, stiffness constant 0.623 +/- 0.107 cm(-2), respectively). In addition, increased inotropic state after dobutamine administration resulted in improved LA pump function (stroke work index) in normal subjects (from 10.2 +/- 0.9 to 13.8 +/- 1.9 cm2 x mm Hg, p < 0.001) and patients with heart failure (from 4.3 +/- 0.4 to 7.6 +/- 0.4 cm2 x mm Hg, p < 0.001), as well as in decreased stiffness constant in all groups of patients (normal subjects: from 0.712 +/- 0.141 to 0.473 +/- 0.089 cm(-2); patients with heart failure: from 0.896 +/- 0.181 to 0.494 +/- 0.093 cm(-2); patients with atrial fibrillation: from 0.779 +/- 0.145 to 0.467 +/- 0.086 cm(-2), p < 0.001). The method described here is both safe and reproducible for obtaining the LA pressure-area relation. LA function is impaired in patients with heart failure and in those with atrial fibrillation and may be acutely improved with inotropic agents in both normal and diseased atria.
    Journal of the American College of Cardiology 02/1998; 31(2):426-36. · 14.09 Impact Factor
  • Journal of The American College of Cardiology - J AMER COLL CARDIOL. 01/1998; 31:351-351.
  • Journal of The American College of Cardiology - J AMER COLL CARDIOL. 01/1998; 31:467-467.
  • Journal of The American College of Cardiology - J AMER COLL CARDIOL. 01/1998; 31:75-75.
  • Journal of The American College of Cardiology - J AMER COLL CARDIOL. 01/1998; 31:283-283.
  • Journal of The American College of Cardiology - J AMER COLL CARDIOL. 01/1998; 31:169-169.