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Biomedical subjects

Stephan Windecker

Publications and source records attributed to Stephan Windecker.

At least 19 recordsLinked to original sources
PubMed2006

Coronary collateral function long after drug-eluting stent implantation.

OBJECTIVES: This study was designed to compare coronary collateral function in patients after bare-metal stent (BMS) or drug-eluting stent (DES) implantation. BACKGROUND: Drug-eluting stents have an inhibitory effect on the production of cytokines, chemotactic proteins, and growth factors, and may therefore negatively affect coronary collateral growth. METHODS: A total of 120 patients with long-term stable coronary artery disease (CAD) after stent implantation were included. Both the BMS group and the DES group comprised 60 patients matched for in-stent stenosis severity of the vessel undergoing collateral flow index (CFI) measurement at follow-up and for the duration of follow-up. The primary end point of the investigation was invasively determined coronary collateral function 6 months after stent implantation. Collateral function was assessed by simultaneous aortic, coronary wedge, and central venous pressure measurements (yielding CFI) and by intracoronary electrocardiogram during balloon occlusion. RESULTS: There were no differences between the groups regarding age, gender, body mass index, frequency of cardiovascular risk factors, use of cardiovascular drugs, severity of CAD, or site of coronary artery stenoses. Despite equal in-stent stenosis severity (46 +/- 34% and 45 +/- 36%) and equal follow-up duration (6.2 +/- 10 months and 6.5 +/- 5.4 months), CFI was diminished in the DES versus BMS group (0.154 +/- 0.097 vs. 0.224 +/- 0.142; p = 0.0049), and the rate of collaterals insufficient to prevent ischemia during occlusion (intracoronary electrocardiographic ST-segment elevation > or =0.1 mV) was higher with 50 of 60 patients in the DES group and 33 of 60 patients in the BMS group (p = 0.001). CONCLUSIONS: Collateral function long after coronary stenting is impaired with DES (sirolimus and paclitaxel) when compared with BMS. Considering the protective nature of collateral vessels, this could lead to more serious cardiac events in the presence of an abrupt coronary occlusion.

Aged↗
PubMed2006

Transcatheter repair of iatrogenic left ventricular free-wall perforation.

Left ventricular free-wall perforation can complicate catheter-based diagnostic or interventional procedures and may require immediate needle pericardiocentesis followed by surgical repair in about 20% of the cases. We describe the transcatheter closure of a left ventricular free-wall perforation as an option in the event of maintained access to the perforation site after defect creation.

Aged↗
PubMed2006

Sirolimus-eluting coronary stents in small vessels.

BACKGROUND: This prospective multicenter study compared angiographic in-lesion late lumen loss in de novo native coronary artery lesions (vessel diameter range 2.25-2.75 mm, length range > or = 15 to < or = 30 mm) 8 months after the implantation of a sirolimus-eluting stent with that of similar vessels with the same drug-eluting stent or a bare stent of the SIRIUS study (historical controls). METHODS AND RESULTS: One hundred one patients (study group) were matched and compared with 323 patients receiving the bare stent (bare control group) and with 350 receiving the Cypher stent (Cypher control group) in the SIRIUS trial. Mean in-lesion late loss in the study group was lower than that in the bare control group (0.20 versus 0.76 mm, P < .0001) and not inferior to that in the Cypher control group (0.27 mm, P = .3). Adverse event rates (death and myocardial infarction) were similar between groups. At 8 months, target lesion revascularization rates were 0% in the study group, 13.2% in the bare control group (P < .001), and 4.6% in the Cypher control group (P = .03). CONCLUSIONS: The Cypher Bx Velocity stent was confirmed to be superior to the bare Bx Velocity stent in small coronary vessels in terms of in-lesion late loss 8 months after implantation.

Angiogenesis Inhibitors↗
PubMed2006

Polymer stent coating for prevention of neointimal hyperplasia.

AIMS: Restenosis has been the principal limitation of bare metal stents. Based upon the presumption that platelet and inflammatory cell recruitment initiate neointimal proliferation, we explored a novel polymer coating that reduces cell-stent interactions. The purpose of the present study was to investigate the effect of poly(L-lysine)-graft-poly(ethyleneglycol) (PLL-g-PEG) adsorbed to stent surfaces to reduce neointimal hyperplasia in the porcine restenosis model. METHODS AND RESULTS: Seven animals were instrumented each with 2 stainless steel stents (15 mm length, 2.5-3.5 mm diameter), randomly implanted in 1 major epicardial coronary artery. One stent was dip-coated with PLL-g-PEG, whereas the other stent served as the uncoated control stent. All animals were sacrificed after 6 weeks for histological examination. Neointimal hyperplasia was significantly less (-51%) in the PLL-g-PEG-coated stents (1.15 +/- 0.59 mm2) than in the uncoated control stents (2.33 +/- 1.01 mm2; p < 0.001). Conversely, lumen size was larger in the PLL-g-PEG-coated stents (2.91 +/- 1.17 mm2) than in the uncoated stents (2.04 +/- 0.64 mm2; p < 0.001). High magnification histomorphologic examination revealed no signs of inflammation or thrombus formation in either stent group. CONCLUSIONS: Polymeric steric stabilization of stents with PLL-g-PEG significantly reduces neointimal hyperplasia in the porcine restenosis model. Reduction of cell-stent interactions mediated by PLL-g-PEG appear to improve biocompatibility of stainless steel stents without evidence of adverse inflammatory or prothrombotic effects.

Angioplasty, Balloon, Coronary↗
PubMed2005

Safety and efficacy of subcutaneous-only granulocyte-macrophage colony-stimulating factor for collateral growth promotion in patients with coronary artery disease.

OBJECTIVES: This study was designed to investigate the safety and efficacy of a short-term subcutaneous-only granulocyte-macrophage colony-stimulating factor (GM-CSF) protocol for coronary collateral growth promotion. BACKGROUND: The safety and efficacy of an exclusively systemic application of GM-CSF in patients with coronary artery disease (CAD) and collateral artery promotion has not been studied so far. METHODS: In 14 men (age 61 +/- 11 years) with chronic stable CAD, the effect of GM-CSF (molgramostim) on quantitatively assessed collateral flow was tested in a randomized, double-blind, placebo-controlled fashion. The study protocol consisted of an invasive collateral flow index (CFI) measurement in a stenotic as well as a normal coronary artery before and after a two-week period with subcutaneous GM-CSF (10 microg/kg; n = 7) or placebo (n = 7). Collateral flow index was determined by simultaneous measurement of mean aortic, distal coronary occlusive, and central venous pressure. RESULTS: Collateral flow index in all vessels changed from 0.116 +/- 0.05 to 0.159 +/- 0.07 in the GM-CSF group (p = 0.028) and from 0.166 +/- 0.06 to 0.166 +/- 0.04 in the placebo group (p = NS). The treatment-induced difference in CFI was +0.042 +/- 0.05 in the GM-CSF group and -0.001 +/- 0.04 in the placebo group (p = 0.035). Among 11 determined cytokines, chemokines, and their monocytic receptor concentrations, the treatment-induced change in CFI was predicted by the respective change in tumor necrosis factor-alpha concentration. Two of seven patients in the GM-CSF group and none in the placebo group suffered an acute coronary syndrome during the treatment period. CONCLUSIONS: A subcutaneous-only, short-term protocol of GM-CSF is effective in promoting coronary collateral artery growth among patients with CAD. However, the drug's safety regarding the occurrence of acute coronary syndrome is questionable.

Aged↗
PubMed2005

Collateral-flow measurements in humans by myocardial contrast echocardiography: validation of coronary pressure-derived collateral-flow assessment.

AIMS: Myocardial blood flow (MBF) is the gold standard to assess myocardial blood supply and, as recently shown, can be obtained by myocardial contrast echocardiography (MCE). The aims of this human study are (i) to test whether measurements of collateral-derived MBF by MCE are feasible during elective angioplasty and (ii) to validate the concept of pressure-derived collateral-flow assessment. METHODS AND RESULTS: Thirty patients with stable coronary artery disease underwent MCE of the collateral-receiving territory during and after angioplasty of 37 stenoses. MCE perfusion analysis was successful in 32 cases. MBF during and after angioplasty varied between 0.060-0.876 mL min(-1) g(-1) (0.304+/-0.196 mL min(-1) g(-1)) and 0.676-1.773 mL min(-1) g(-1) (1.207+/-0.327 mL min(-1) g(-1)), respectively. Collateral-perfusion index (CPI) is defined as the rate of MBF during and after angioplasty varied between 0.05 and 0.67 (0.26+/-0.15). During angioplasty, simultaneous measurements of mean aortic pressure, coronary wedge pressure, and central venous pressure determined the pressure-derived collateral-flow index (CFI(p)), which varied between 0.04 and 0.61 (0.23+/-0.14). Linear-regression analysis demonstrated an excellent agreement between CFI(p) and CPI (y=0.88 x +0.01; r(2)=0.92; P<0.0001). CONCLUSION: Collateral-derived MBF measurements by MCE during angioplasty are feasible and proved that the pressure-derived CFI exactly reflects collateral relative to normal myocardial perfusion in humans.

Blood Flow Velocity↗
PubMed2005

Sirolimus-eluting and paclitaxel-eluting stents for coronary revascularization.

BACKGROUND: Sirolimus-eluting stents and paclitaxel-eluting stents, as compared with bare-metal stents, reduce the risk of restenosis. It is unclear whether there are differences in safety and efficacy between the two types of drug-eluting stents. METHODS: We conducted a randomized, controlled, single-blind trial comparing sirolimus-eluting stents with paclitaxel-eluting stents in 1012 patients undergoing percutaneous coronary intervention. The primary end point was a composite of major adverse cardiac events (death from cardiac causes, myocardial infarction, and ischemia-driven revascularization of the target lesion) by nine months. Follow-up angiography was completed in 540 of 1012 patients (53.4 percent). RESULTS: The two groups had similar baseline clinical and angiographic characteristics. The rate of major adverse cardiac events at nine months was 6.2 percent in the sirolimus-stent group and 10.8 percent in the paclitaxel-stent group (hazard ratio, 0.56; 95 percent confidence interval, 0.36 to 0.86; P=0.009). The difference was driven by a lower rate of target-lesion revascularization in the sirolimus-stent group than in the paclitaxel-stent group (4.8 percent vs. 8.3 percent; hazard ratio, 0.56; 95 percent confidence interval, 0.34 to 0.93; P=0.03). Rates of death from cardiac causes were 0.6 percent in the sirolimus-stent group and 1.6 percent in the paclitaxel-stent group (P=0.15); the rates of myocardial infarction were 2.8 percent and 3.5 percent, respectively (P=0.49); and the rates of angiographic restenosis were 6.6 percent and 11.7 percent, respectively (P=0.02). CONCLUSIONS: As compared with paclitaxel-eluting stents, the use of sirolimus-eluting stents results in fewer major adverse cardiac events, primarily by decreasing the rates of clinical and angiographic restenosis.

Angioplasty, Balloon, Coronary↗
PubMed2005

Sirolimus-eluting stents associated with paradoxic coronary vasoconstriction.

OBJECTIVES: The purpose of the present study was to assess coronary vasomotor response to exercise after sirolimus-eluting stent (SES) implantation. BACKGROUND: Sirolimus-eluting stents have been shown to markedly reduce the incidence of angiographic and clinical restenosis. However, long-term effects of sirolimus on endothelial function are unknown. METHODS: Coronary vasomotion was evaluated with biplane quantitative coronary angiography at rest and during supine bicycle exercise in 25 patients with coronary artery disease. Eleven patients were treated with a bare-metal stent (BMS) (control group) and 14 patients underwent SES implantation (sirolimus group) for de novo coronary artery lesions. Both groups were studied 6 +/- 1 month after the intervention. Minimal luminal diameter; stent diameter; and proximal, distal, and reference vessel diameter were determined. RESULTS: The reference vessel showed exercise-induced vasodilation (+13 +/- 4%) in both groups. Vasomotion within the stented vessel segments was abolished. In controls, the adjacent segments proximal and distal to the stent showed exercise-induced vasodilation (+15 +/- 3% and +17 +/- 4%, respectively). In contrast, there was exercise-induced vasoconstriction of the proximal and distal vessel segments adjacent to SESs (-12 +/- 4% and -15 +/- 6%, respectively; p < 0.001 vs. corresponding segments of controls). Sublingual nitroglycerin was associated with maximal vasodilation of the proximal and distal vessel segments in both groups. CONCLUSIONS: Implantation of a BMS does not affect physiologic response to exercise proximal and distal to the stent. However, SESs are associated with exercise-induced paradoxic coronary vasoconstriction of the adjacent vessel segments, although vasodilatory response to nitroglycerin is maintained. These observations suggest (drug-induced) endothelial dysfunction as the underlying mechanism.

Case-Control Studies↗
PubMed2005

Percutaneous catheter thrombectomy device for acute pulmonary embolism: in vitro and in vivo testing.

PURPOSE: To evaluate a percutaneous pulmonary embolism (PE) thrombectomy catheter that aspirates, macerates, and removes thrombus. MATERIALS AND METHODS: Nine in vitro tests were performed by using porcine thrombi at a PE test station that provides continuous fluid output of 2 L/min at a pressure of 50 mmHg. Macroembolization was defined as embolized particles larger than 1.5 mm in dimension; microembolization was defined as particles that range in size from 0.1 to 1.5 mm. In static in vitro tests, researchers measured plasma-free hemoglobin levels in a 36-year-old man to assess mechanical hemolysis. Investigational review board approval and informed consent were obtained. The Department of Agriculture, Veterinary Bureau, Bern, Switzerland approved in vivo tests. Researchers investigated device effectiveness in 10 pigs that developed cardiogenic shock but survived massive PE after injection of two or three porcine thrombi into the external jugular vein via a surgically implanted 24-F sheath. Pulmonary angiography and hemodynamic measurements, including mean aortic and mean pulmonary artery pressure, heart rate, and mixed venous oxygen saturation, were obtained at baseline, after embolization, and after thrombectomy. Repeated-measures analysis of variance was performed to compare hemodynamic measurements at baseline, after embolization, and after thrombectomy. Cardiovascular structures were examined at necropsy for rupture, perforation, dissection, or hemorrhage. RESULTS: During a mean aspiration time of 69 seconds +/- 19, thrombi were completely extracted from 14-mm test tubes, with an aspirated fluid volume of 201 mL +/- 64. Although no macroembolization was observed, microembolization was quantified at 1.9 g +/- 1.3. Catheter aspiration was not associated with an increase in plasma-free hemoglobin. In 10 animals, aortic pressure increased from 52 mmHg +/- 24 before thrombectomy to 90 mmHg +/- 32 after thrombectomy, mixed venous oxygen saturation increased from 48% +/- 19% to 61% +/- 12%, pulmonary artery pressure decreased from 33 mmHg +/- 9 to 22 mmHg +/- 4, and heart rate decreased from 162 beats per minute +/- 24 to 114 beats per minute +/- 14. We did not observe macro- or microscopic damage to treated or untreated cardiovascular structures. CONCLUSION: The PE thrombectomy device was highly effective, facilitating rapid reversal of cardiogenic shock without device-related complications.

Acute Disease↗
PubMed2005

Stent thrombosis is associated with an impaired response to antiplatelet therapy.

OBJECTIVES: We sought to evaluate the response to antiplatelet therapy in patients with stent thrombosis (ST). BACKGROUND: Stent thrombosis is associated with considerable morbidity and mortality. An impaired response to antiplatelet therapy might be related to an increased risk for ST. METHODS: Eighty-two patients were included in the present study: 23 patients with previous ST, 50 matched controls (coronary stenting without ST), and 9 healthy volunteers. Platelet aggregation (PA) was studied (optical aggregometry) under monotherapy with acetylsalicylic acid (ASA) 100 mg daily for one month, followed by dual therapy with ASA 100 mg and clopidogrel 75 mg daily (loading dose 300 mg) for another month. RESULTS: Maximal (5 and 20 micromol) adenosine diphosphate-induced PA was significantly higher in patients with ST compared with controls (5 micromol, p < 0.005; 20 micromol, p < 0.05) and volunteers (5 micromol, p < 0.005; 20 micromol, p < 0.05). Resistance to ASA (>20% aggregation with 0.5 mg/ml arachidonic acid) was more prevalent in patients with ST (48%) compared with control patients (32%, p = ns) and volunteers (0%, p = 0.01). Clopidogrel significantly reduced PA in all three groups, but intergroup differences persisted. Clopidogrel resistance (<10% relative change) was similar in patients with ST, control patients, and volunteers (4%, 6%, and 11%, respectively, all p = NS). However, combined ASA and clopidogrel resistance was more prevalent in patients with ST (52%) compared with controls (38%, p = NS) and volunteers (11%, p < 0.05). CONCLUSIONS: Patients with previous ST show an impaired response to antiplatelet therapy with ASA compared with controls and volunteers. Additional treatment with clopidogrel is not able to overcome these differences in PA. Acetylsalicylic acid but not clopidogrel resistance appears to be associated with ST.

Aged↗
PubMed2005

Randomized comparison of a titanium-nitride-oxide-coated stent with a stainless steel stent for coronary revascularization: the TiNOX trial.

BACKGROUND: Stent coating with titanium-nitride-oxide has been shown to reduce neointimal hyperplasia in the porcine restenosis model. We designed a prospective, randomized, clinical study to investigate the safety and efficacy of titanium-nitride-oxide-coated stents compared with stainless steel stents. METHODS AND RESULTS: Ninety-two patients with de novo lesions were randomly assigned to treatment with titanium-nitride-oxide-coated stents (n=45) or stainless steel stents of otherwise identical design (n=47; control). Baseline characteristics were similar in both groups. At 30 days, no stent thromboses or other adverse events had occurred in either group. Quantitative coronary angiography at 6 months revealed lower late loss (0.55+/-0.63 versus 0.90+/-0.76 mm, P=0.03) and percent diameter stenosis (26+/-17% versus 36+/-24%, P=0.04) in lesions treated with titanium-nitride oxide-coated than in control stents. Binary restenosis was reduced from 33% in the control group to 15% in the titanium-nitride oxide-coated stent group (P=0.07). Intravascular ultrasound studies at 6 months showed smaller neointimal volume in titanium-nitride-oxide-coated stents than in control stents (18+/-21 versus 48+/-28 mm3, P<0.0001). Major adverse cardiac events at 6 months were less frequent in titanium-nitride-oxide-coated stents than in control stent-treated patients (7% versus 27%, P=0.02), largely driven by a reduced need for target-lesion revascularization (7% versus 23%, P=0.07). CONCLUSIONS: Revascularization with titanium-nitride-oxide-coated stents is safe and effective in patients with de novo native coronary artery lesions. Titanium-nitride-oxide-coated stents reduce restenosis and major adverse cardiac events compared with stainless steel stents of otherwise identical design.

Aged↗
PubMed2005

Stent thrombosis following bare-metal stent implantation: success of emergency percutaneous coronary intervention and predictors of adverse outcome.

AIMS: To investigate the efficacy and outcome of emergency percutaneous coronary interventions (PCI) in patients with stent thrombosis. METHODS AND RESULTS: Between 1995 and 2003, 6058 patients underwent bare-metal stent implantation, of which 95 (1.6%) patients suffered from stent thrombosis. The timing of stent thrombosis was acute in 10 (11%), subacute in 61 (64%), and late in 24 (25%) patients. Procedural and clinical outcomes of emergency PCI for treatment of stent thrombosis were investigated. Emergency PCI was successful in 86 (91%), complicated by death in 2 (2%), and coronary artery bypass grafting in 2 (2%) patients. Myocardial infarction occurred in 77 (81%) patients with a peak creatine kinase level of 1466+/-1570 U/L. Left ventricular ejection fraction declined from 0.54+/-0.19 prior to 0.48+/-0.16 (P<0.05) at the time of stent thrombosis after emergency PCI. A 6 month major adverse clinical events comprised death (11%), reinfarction (16%), and recurrent stent thrombosis (12%) after emergency PCI. Multivariable logistic regression analysis identified the achievement of TIMI 3 flow (OR=0.1, CI 95% 0.01-0.54, P<0.001) and diameter stenosis <50% (OR=0.06, CI 95% 0.01-0.32, P<0.001) during emergency PCI to be independently associated with a reduced risk of cardiac death. Recurrent stent thrombosis was independently predicted by the omission of abciximab (OR=4.3, CI 95% 1.1-17.5). CONCLUSION: Emergency PCI for treatment of stent thrombosis effectively restores vessel patency and flow. Patients presenting with stent thrombosis are at risk for recurrent myocardial infarction and recurrent stent thrombosis.

Abciximab↗
PubMed2005

Transcatheter treatment of atrial septal aneurysm associated with patent foramen ovale for prevention of recurrent paradoxical embolism in high-risk patients.

OBJECTIVES: This study sought to investigate the safety and efficacy of transcatheter treatment of atrial septal aneurysm (ASA) associated with patent foramen ovale (PFO). BACKGROUND: Patients with both ASA and PFO are at high risk for recurrent paradoxical embolism. METHODS: The procedural, echocardiographic, and clinical outcomes of 141 patients with ASA + PFO and > or =1 paradoxical embolic event undergoing transcatheter treatment were compared with 220 patients with PFO alone. RESULTS: Device success (ASA + PFO, 99.3%; PFO alone, 99.5%; p = 0.75) and procedural complications (ASA + PFO, 0.7%; PFO alone, 3.2%; p = 0.12) were similar in both groups. Maximal atrial septal excursion in patients with ASA + PFO decreased from 16 +/- 4 mm before to 4 +/- 3 mm after the intervention (p < 0.0001). At 6 months follow-up, right-to-left shunt was abolished in 120 (86%) patients with ASA + PFO, compared to 187 (85%) patients with PFO alone (p = 0.80). Freedom from recurrent transient ischemic attack, stroke, and peripheral embolism at 4 years was 95% (ASA + PFO) and 94% (PFO alone, p = 0.70), respectively. A residual right-to-left shunt after the intervention was the only predictor for recurrence (hazard ratio [HR] 6.9; 95% confidence interval [CI] 1.3 to 36.9, p < 0.03) in patients with ASA + PFO. CONCLUSIONS: Transcatheter treatment of ASA + PFO is safe and effective in patients with paradoxical embolism. The procedure effectively abolishes right-to-left shunt and decreases atrial septal mobility. Long-term prevention of recurrent events appears favorable when compared to patients with PFO alone.

Adult↗
PubMed2005

Tumour necrosis factor-alpha and interleukin-6 release during primary percutaneous coronary intervention for acute myocardial infarction is related to coronary collateral flow.

OBJECTIVES: We tested the hypothesis that there was an association between tumour necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) release and measured coronary collateral flow in patients undergoing primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI). BACKGROUND: Tumour necrosis factor-alpha and IL-6 increase during acute myocardial infarction (AMI). However, their relation to coronary collateral flow is unknown. METHODS: Twelve patients with AMI due to complete thrombotic coronary occlusion underwent primary PCI within 12 h of symptom onset. Doppler-derived collateral flow index (CFI) was measured during first balloon inflation. TNF-alpha, IL-6, creatine kinase (CK), CK-MB fraction were measured from venous plasma samples serially for 24 h. Area at risk was determined off-line by coronary arteriography. Ejection fraction (EF) was measured using biplane left ventricular angiography. RESULTS: Maximal CK release varied between 569 and 6276 U/l and area at risk varied between 7 and 47% of myocardium. Tumour necrosis factor-alpha (peak 4.4+/-0.5 pg/ml) and IL-6 (peak 35.5+/-3.0 pg/ml) increased in all patients. Peak TNF-alpha and IL-6 release was independent of CK, CKMB. No minimal threshold of myocardial necrosis for cytokine expression could be detected. Similarly, TNF-alpha and IL-6 release was also independent of time to reperfusion, area at risk or EF. Using univariate regression analysis, peak TNF-alpha inversely correlated with CFI (r = 0.67, P = 0.017) whereas IL-6 positively correlated with CFI (r = 0.76, P = 0.004). CONCLUSIONS: Acute myocardial infarction is associated with a significant rise in TNF-alpha and IL-6 levels independent of infarct size or myonecrosis. Tumour necrosis factor-alpha and IL-6 correlate dichotomously with CFI indicating differing roles in reperfused AMI.

Aged↗
PubMed2004

Reciprocal relationship between left ventricular filling pressure and the recruitable human coronary collateral circulation.

AIMS: The aim of our study in patients with coronary artery disease (CAD) and present, or absent, myocardial ischaemia during coronary occlusion was to test whether (i) left ventricular (LV) filling pressure is influenced by the collateral circulation and, on the other hand, that (ii) its resistance to flow is directly associated with LV filling pressure. METHODS AND RESULTS: In 50 patients with CAD, the following parameters were obtained before and during a 60 s balloon occlusion: LV, aortic (Pao) and coronary pressure (Poccl), flow velocity (Voccl), central venous pressure (CVP), and coronary flow velocity after coronary angioplasty (V(Ø-occl)). The following variables were determined and analysed at 10 s intervals during occlusion, and at 60 s of occlusion: LV end-diastolic pressure (LVEDP), velocity-derived (CFIv) and pressure-derived collateral flow index (CFIp), coronary collateral (Rcoll), and peripheral resistance index to flow (Rperiph). Patients with ECG signs of ischaemia during coronary occlusion (insufficient collaterals, n = 33) had higher values of LVEDP over the entire course of occlusion than those without ECG signs of ischaemia during occlusion (sufficient collaterals, n = 17). Despite no ischaemia in the latter, there was an increase in LVEDP from 20 to 60 s of occlusion. In patients with insufficient collaterals, CFIv decreased and CFIp increased during occlusion. Beyond an occlusive LVEDP > 27 mmHg, Rcoll and Rperiph increased as a function of LVEDP. CONCLUSION: Recruitable collaterals are reciprocally tied to LV filling pressure during occlusion. If poorly developed, they affect it via myocardial ischaemia; if well grown, LV filling pressure still increases gradually during occlusion despite the absence of ischaemia indicating transmission of collateral perfusion pressure to the LV. With low, but not high, collateral flow, resistance to collateral as well as coronary peripheral flow is related to LV filling pressure in the high range.

Aged↗
PubMed2004

Comparison of medical treatment with percutaneous closure of patent foramen ovale in patients with cryptogenic stroke.

OBJECTIVES: The purpose of this study was to compare the efficacy of medical treatment with percutaneous closure of patent foramen ovale (PFO). BACKGROUND: Patients with cryptogenic stroke and PFO are at risk for recurrent cerebrovascular events. METHODS: We compared the risk of recurrence in 308 patients with cryptogenic stroke and PFO, who were treated either medically (158 patients) or underwent percutaneous PFO closure (150 patients) between 1994 and 2000. RESULTS: Patients undergoing percutaneous PFO closure had a larger right-to-left shunt (p < 0.001; 95% confidence interval [CI] 1.38 to 3.07) and were more likely to have suffered more than one cerebrovascular event (p = 0.03; 95% CI 1.04 to 2.71). At four years of follow-up, percutaneous PFO closure resulted in a non-significant trend toward risk reduction of death, stroke, or transient ischemic attack (TIA) combined (8.5% vs. 24.3%; p = 0.05; 95% CI 0.23 to 1.01), and of recurrent stroke or TIA (7.8% vs. 22.2%; p = 0.08; 95% CI 0.23 to 1.11) compared with medical treatment. Patients with more than one cerebrovascular event at baseline and those with complete occlusion of PFO were at lower risk for recurrent stroke or TIA after percutaneous PFO closure compared with medically treated patients (7.3% vs. 33.2%; p = 0.01; 95% CI 0.08 to 0.81, and 6.5% vs. 22.2%; p = 0.04; 95% CI 0.14 to 0.99, respectively). CONCLUSIONS: Percutaneous PFO closure appears at least as effective as medical treatment for prevention of recurrent cerebrovascular events in cryptogenic stroke patients with PFO. It might be more effective than medical treatment in patients with complete closure and more than one cerebrovascular event.

Adolescent↗
PubMed2004

Deleterious effect of coronary brachytherapy on vasomotor response to exercise.

BACKGROUND: Intracoronary radiotherapy (brachytherapy) has been proposed as treatment option for in-stent restenosis. Long-term results of brachytherapy with regard to vascular integrity and vasomotor responsiveness are unknown. The purpose of the present study was to determine the vasomotor response after brachytherapy and to assess its influence on vasomotion during exercise. METHODS AND RESULTS: Biplane quantitative coronary angiography was performed at rest and during bicycle exercise in 27 patients with coronary artery disease. Fourteen patients underwent coronary stenting and were studied 10+/-3 months after intervention (control group). Thirteen patients were treated with brachytherapy (Guidant Galileo System) for in-stent restenosis with a mean dosis of 20 Gy at 1 mm into the vessel wall and were studied 9+/-1 months after radiation (brachytherapy group). Minimal luminal area, stent area, and proximal, distal, and a reference vessel area were determined. The reference vessel showed exercise-induced vasodilation (26+/-4%, P<0.001) in both groups. Vasomotion within the stented vessel segments was abolished. In control subjects, the proximal and distal segments showed exercise-induced vasodilation (17+/-2% and 22+/-7%, respectively; P<0.005). In contrast, there was exercise-induced vasoconstriction in the proximal and distal vessel segments of the brachytherapy group (-14+/-3% and -16+/-4%, respectively; P<0.01). Sublingual nitroglycerin was associated with maximal vasodilation of the proximal and distal vessel segments in both groups. CONCLUSIONS: Normal vessel segments elicit flow-mediated vasodilation during exercise. Stent implantation does not affect physiological response to exercise proximal and distal to the stent. Brachytherapy eliminates exercise-induced vasodilation, although dilatory response to nitroglycerin is maintained, suggesting endothelial dysfunction as the underlying mechanism.

Aged↗