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Biomedical subjects

S Windecker

Publications and source records attributed to S Windecker.

At least 19 recordsLinked to original sources
PubMed2005

Efficacy of drug eluting stents in patients with and without diabetes mellitus: indirect comparison of controlled trials.

OBJECTIVE: To examine whether polymer based coronary stents eluting sirolimus or paclitaxel are equally effective in patients with and without diabetes. METHODS: Systematic review and meta-analysis by indirect comparison of randomised controlled trials comparing stents eluting sirolimus or paclitaxel with conventional bare metal stents. The overall study population and patients with and without diabetes were analysed separately by using the ratio of incidence rate ratios (RIRR). RESULTS: The analysis was based on 10 trials (six with sirolimus, four with paclitaxel), 4513 patients (1146 patients with diabetes), 5755 years of follow up, and 2464 events. In patients without diabetes sirolimus eluting stents were superior to paclitaxel eluting stents with respect to in-stent (RIRR 0.21, 95% confidence interval (CI) 0.10 to 0.48, p < 0.001) and in-segment restenosis (RIRR 0.47, 95% CI 0.24 to 0.92, p = 0.027), target lesion revascularisation (RIRR 0.54, 95% CI 0.30 to 0.99, p = 0.045), and major adverse cardiac events (RIRR 0.46, 95% CI 0.26 to 0.83, p = 0.010). In patients with diabetes the two drug eluting stents did not differ significantly in any of these end points. Meta-regression analysis showed a significant difference between patients with and without diabetes (tests for interaction for in-stent and in-segment restenosis, p = 0.036 and p = 0.016). CONCLUSION: Indirect evidence indicates that sirolimus eluting stents are superior to paclitaxel eluting stents in patients without diabetes but not in patients with diabetes.

Blood Vessel Prosthesis↗
PubMed2005

Prevalence and size of directly detected patent foramen ovale in migraine with aura.

BACKGROUND: Transcranial contrast Doppler studies have shown an increased prevalence of right-to-left shunts in patients with migraine with aura compared with controls. The anatomy and size of these right-to-left shunts have never been directly assessed. METHODS: In a cross-sectional case-control study, the authors performed transesophageal contrast echocardiography in 93 consecutive patients with migraine with aura and 93 healthy controls. RESULTS: A patent foramen ovale was present in 44 (47% [95% CI 37 to 58%]) patients with migraine with aura and 16 (17% [95% CI 10 to 26%]) control subjects (OR 4.56 [95% CI 1.97 to 10.57]; p < 0.001). A small shunt was equally prevalent in migraineurs (10% [95% CI 5 to 18%]) and controls (10% [95% CI 5 to 18%]), but a moderate-sized or large shunt was found more often in the migraine group (38% [95% CI 28 to 48%] vs 8% [95% CI 2 to 13%] in controls; p < 0.001). The presence of more than a small shunt increased the odds of having migraine with aura 7.78-fold (95% CI 2.53 to 29.30; p < 0.001). Besides patent foramen ovale prevalence and shunt size, no other echocardiographic differences were found between the study groups. Headache and baseline characteristics did not differ in migraine patients with and without shunt. CONCLUSIONS: Nearly half of all patients with migraine with aura have a right-to-left shunt due to a patent foramen ovale. Shunt size is larger in migraineurs than controls. The clinical presentation of migraine is identical in patients with and without a patent foramen ovale.

Adult↗
PubMed2005

Influence of diabetes mellitus on coronary collateral flow: an answer to an old controversy.

OBJECTIVES: To determine the influence of diabetes mellitus on coronary collateral flow by accurate means of collateral flow measurement in a large population with variable degrees of coronary artery disease. METHODS: 200 patients (mean (SD) age 64 (9) years; 100 diabetic and 100 non-diabetic) were enrolled in the study. Coronary collateral flow was assessed in 174 stenotic and in 26 angiographically normal vessels with a pressure guidewire (n = 131), Doppler guidewire (n = 36), or both (n = 33) to calculate pressure or flow velocity derived collateral flow index (CFI). Diabetic patients were perfectly matched with a non-diabetic control group for clinical, haemodynamic, and angiographic parameters. RESULTS: CFI did not differ between the diabetic and the non-diabetic patients (0.21 (0.12) v 0.19 (0.13), not significant). Likewise, CFI did not differ when only angiographically normal vessels (0.20 (0.09) v 0.15 (0.08), not significant) or chronic total coronary occlusions (0.30 (0.14) v 0.30 (0.17), not significant) were compared. Fewer patients in the diabetic group tended to have angina pectoris during the one minute vessel occlusion (60 diabetic v 69 non-diabetic patients, p = 0.15). CONCLUSION: Quantitatively measured coronary CFI did not differ between diabetic and non-diabetic patients with stable coronary artery disease.

Blood Flow Velocity↗
PubMed2004

Percutaneous closure of patent foramen ovale reduces the frequency of migraine attacks.

Among 215 patients referred for percutaneous closure of patent foramen ovale (PFO) after presumed paradoxical embolism, we assessed the prevalence of migraine. In the year prior to PFO closure, 48 (22%) patients had migraine, twice the expected prevalence of 10 to 12% in the general European population. In patients with migraine with aura, percutaneous PFO closure reduced the frequency of migraine attacks by 54% (1.2 +/- 0.8 vs 0.6 +/- 0.8 per month; p = 0.001) and in patients with migraine without aura by 62% (1.2 +/- 0.7 vs 0.4 +/- 0.4 per month; p = 0.006). PFO closure did not have an effect on headache frequency in patients with nonmigraine headaches (1.4 +/- 0.9 vs 1.0 +/- 0.9 per month; p = NS).

Adult↗
PubMed2004

Percutaneous closure of patent foramen ovale: impact of device design on safety and efficacy.

OBJECTIVE: To compare the safety and efficacy of percutaneous closure of patent foramen ovale (PFO) with the Amplatzer PFO occluder (Amplatzer) or the PFO STAR device (STAR) in patients with presumed paradoxical embolism. METHODS: Implantation characteristics, procedural complications, residual shunt, and recurrence of thromboembolic events were recorded prospectively in 100 consecutive patients undergoing percutaneous PFO closure with the STAR (n = 50) or Amplatzer (n = 50) devices between 1998 and 2001. The study was not randomised. Device implantation was successful in all cases. RESULTS: There were more procedural complications in the STAR than in the Amplatzer group (8/50 v 1/50, p = 0.01). More than one device placement attempt was an independent predictor of procedural complications (odds ratio (OR) 8.5, 95% confidence interval (CI) 1.3 to 55.8; p = 0.03). A residual shunt six months after PFO closure, assessed by transoesophageal contrast echocardiography, occurred more often in the STAR than the Amplatzer group (17/50 v 3/50, p = 0.004), and was predicted in the STAR group by the use of a device with a 5 mm as opposed to a 3 mm disc connector (OR 6.1, 95% CI 1.1 to 34.0; p = 0.04). The actuarial risk of recurrent thromboembolic events after 3.5 years was 16.8% (95% CI 7.6% to 34.6%) in the STAR and 2.7% (95% CI 0.4% to 17.7%) in the Amplatzer group after three years (p = 0.08). CONCLUSIONS: Percutaneous PFO closure with the Amplatzer PFO occluder had fewer procedural complications and was more likely to be complete than with the STAR device. These findings underline the importance of device design for successful percutaneous PFO closure.

Balloon Occlusion↗
PubMed2003

Novel management strategy for patients with suspected pulmonary embolism.

AIMS: A simple management strategy is required for patients with acute pulmonary embolism which allows a rapid and reliable diagnosis in order to start timely and appropriate treatment. METHODS AND RESULTS: Two hundred and four consecutive patients with suspected pulmonary embolism were managed according to a standardized protocol based on the clinical pretest probability and the initial haemodynamic presentation (shock index=heart rate divided by systolic blood pressure). Patients with a high pretest probability and a positive shock index (> or =1) (n=21) underwent urgent transthoracic echocardiography. Based on the presence or absence of right ventricular dysfunction, reperfusion treatment was initiated immediately. Patients with a negative shock index (<1) (n=183) underwent diagnostic evaluation including pretest probability, D-dimer, and spiral computed tomography (CT) as first-line tests. Echocardiography was performed only when a central pulmonary embolism was found in the spiral CT(n=33). According to our strategy, 98 patients met the diagnostic criteria of pulmonary embolism: 75 patients (all shock index <1) were treated with heparin alone, 16 (seven had a shock index > or =1) with thrombolysis, four (all shock index > or =1) with catheter fragmentation, and three (all shock index > or =1) with surgical embolectomy. The all-cause mortality rate at 30 days was 5%, and at 6 months 11%. Right ventricular dysfunction on baseline echocardiography was not associated with a higher mortality rate at 6 months (logrank 2.4, P=0.12). CONCLUSIONS: The novel management strategy for patients with suspected pulmonary embolism resulted in a rapid diagnosis and treatment with a low 30-day mortality. In patients with pulmonary embolism and a positive shock index, time-consuming imaging tests can be avoided to reduce the risk of sudden death and not to delay reperfusion therapy.

Acute Disease↗
PubMed2003

[Cryptogenic stroke and patent foramen ovale].

A stroke of unknown etiology is commonly referred to as cryptogenic and is diagnosed in a considerable patient population of especially young age. Numerous case-control studies revealed a strong and consistent association between cryptogenic stroke and the presence of a patent foramen ovale. This relationship corroborates paradoxical embolism as likely stroke mechanism in this patient population. In approximately twenty-five percent of patients with cryptogenic stroke, the patent foramen ovale is accompanied by an atrial septal aneurysm, which considerably heightens the risk for recurrent neurological events. Therapeutic measures for secondary prevention in this patient population encompass medical treatment with antiplatelet agents or anticoagulants and surgical or percutaneous closure of patent foramen ovale. Currently, randomised clinical studies compare medical treatment with closure of patent foramen ovale to determine the most effective treatment strategy in this patient population.

Administration, Oral↗
PubMed2002

Outcome of patients with cryptogenic stroke and patent foramen ovale.

OBJECTIVES: The aim was to estimate the recurrence rate and to define subgroups at increased risk for recurrent cerebral ischaemia in patients with patent foramen ovale (PFO) and so called cryptogenic stroke due to paradoxical embolism. METHODS: Patent foramen ovale was diagnosed in 318 patients with otherwise unexplained ischaemic stroke or transient ischaemic attack (TIA). One hundred and fifty nine were treated medically (oral anticoagulation 79, platelet inhibitors 80) and represent the study population. The remaining 159 patients underwent endovascular or surgical closure of the PFO and are not part of this study. RESULTS: Mean age was 50.7 (SD 13.5) years. The event leading to the diagnosis of PFO was a TIA in 38 patients (23.9%), an ischaemic stroke in 119 (74.8%), and an amaurosis fugax in two patients (1.3%). Forty four patients (27.7%) had experienced multiple cerebrovascular ischaemic events before the diagnosis of the PFO. During mean follow up of 29 (SD 23) months 21 patients (13.4%) had a recurrent cerebrovascular event (seven strokes and 14 TIAs). The average annual rate of recurrent strokes was 1.8% and that of recurrent strokes or TIAs was 5.5%. When patients with PFO with multiple cerebrovascular events before the diagnosis of the PFO were analyzed separately, the average annual rates of recurrent cerebral ischaemia were 3.6% for recurrent strokes and 9.9% for recurrent strokes or TIAs. These rates were significantly higher than in patients with first ever stroke or TIA (p=0.02). CONCLUSIONS: The study confirms a risk of stroke recurrence that is similar to the rates of previously published series of patients with PFO and cryptogenic strokes. Patients with more than one previous event were at increased risk of recurrent cerebral ischaemia.

Adolescent↗
PubMed2001

Promotion of collateral growth by granulocyte-macrophage colony-stimulating factor in patients with coronary artery disease: a randomized, double-blind, placebo-controlled study.

BACKGROUND: Experimentally, activated macrophages have been documented to induce vascular proliferation. METHODS AND RESULTS: In 21 patients (age 74+/-9 years) with extensive coronary artery disease not eligible for coronary artery bypass surgery, the effect of granulocyte-macrophage colony-stimulating factor (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 immediately before intracoronary injection of 40 microg of GM-CSF (n=10) or placebo (n=11) and after a 2-week period with subcutaneous GM-CSF (10 microg/kg) or placebo, respectively. CFI was determined by simultaneous measurement of mean aortic pressure (P(ao), mm Hg), distal coronary occlusive pressure (P(occl), mm Hg; using intracoronary sensor guidewires), and central venous pressure (CVP, mm Hg): CFI=(P(occl)-CVP)/(P(ao)-CVP). CFI, expressing collateral flow during coronary occlusion relative to normal antegrade flow during vessel patency, changed from 0.21+/-0.14 to 0.31+/-0.23 in the GM-CSF group (P<0.05) and from 0.30+/-0.16 to 0.23+/-0.11 in the placebo group (P=NS). The treatment-induced difference in CFI was +0.11+/-0.12 in the GM-CSF group and -0.07+/-0.12 in the placebo group (P=0.01). ECG signs of myocardial ischemia during coronary balloon occlusion occurred in 9 of 10 patients before and 5 of 10 patients after GM-CSF treatment (P=0.04), whereas they were observed in 5 of 11 patients before and 8 of 11 patients after placebo (P=NS). CONCLUSIONS: This first clinical study investigating the potential of GM-CSF to improve collateral flow in patients with coronary artery disease documents its efficacy in a short-term administration protocol.

Aged↗
PubMed2001

Prognosis after percutaneous closure of patent foramen ovale for paradoxical embolism.

The long-term risk and risk factors for recurrent embolism after percutaneous closure of patent foramen ovale (PFO) were investigated in 152 consecutive patients with presumed paradoxical embolism. During follow-up, the actuarial freedom from recurrent embolism was 95.1% at 1 year, and 90.6% at 2 and 6 years. A residual shunt after percutaneous PFO closure was a predictor for recurrence (RR 5.3; 95% CI 1.3 to 21.0; p = 0.02). Randomized trials comparing medical treatment with percutaneous PFO closure in the prevention of recurrent embolism are in progress.

Adult↗
PubMed2001

Stent coating with titanium-nitride-oxide for reduction of neointimal hyperplasia.

BACKGROUND: Coronary stents prevent constrictive arterial remodeling but stimulate neointimal hyperplasia. Stainless steel induces a metallic foreign body reaction, which is absent for titanium. The hypothesis of the present study was that titanium renders the stent surface biologically inert, with reduced platelet and fibrinogen binding. METHODS AND RESULTS: Twelve pigs were instrumented with a stainless steel and 2 titanium-nitride-oxide-coated stents (TiNOX 1, ceramic; TiNOX 2, metallic). Animals were restudied after 6 weeks. Histological specimens of stented segments were analyzed by digital morphometry. Platelet adhesion and fibrinogen binding studies were performed in the perfusion chamber. Under in vitro conditions, TiNOX 1 showed reduced platelet adhesion (65+/-3%) compared with TiNOX 2 (72+/-5%; P<0.05) and stainless steel (71+/-4%; P<0.05). Platelet adhesion 48 hours after incubation with human plasma, however, was not different between TiNOX 1 (17+/-3%) and 2 (15+/-3%) but was significantly higher with stainless steel (23+/-2%; P<0.05). Fibrinogen binding was significantly reduced with TiNOX 2 (54+/-3%) compared with TiNOX 1 (82+/-4%, P<0.05) or stainless steel (100%, P<0.05). Histomorphometry revealed a significantly larger neointimal area in stainless steel (2.61+/-1.12 mm(2)) than in TiNOX 1-coated (1.47+/-0.84 mm(2), P<0.02) or TiNOX 2-coated (1.39+/-0.93 mm(2), P<0.02) stents. The reductions were 44% and 47%, respectively. CONCLUSIONS: TiNOX coating significantly reduces neointimal hyperplasia in stainless steel stents. The antiproliferative effect was similar for both TiNOX coatings, suggesting that the electrochemical properties are more important for attenuation of neointimal proliferation than the observed differences in platelet adhesion and fibrinogen binding.

Alloys↗
PubMed2001

Sympathetic stimulation using the cold pressor test increases coronary collateral flow.

BACKGROUND: Little is known about the vasomotor function of human coronary collateral vessels. The purpose of this study was to examine collateral flow under a strong sympathetic stimulus (cold pressor test, CPT). METHODS: In 30 patients (62 +/- 12 years) with coronary artery disease, two subsequent coronary artery occlusions were performed with random CPT during one of them. Two minutes before and during the 1 minute-occlusion, the patient's hand was immerged in ice water. For the calculation of a perfusion pressure-independent collateral flow index (CFI), the aortic (Pao), the central venous (CVP) and the coronary wedge pressure (Poccl) were measured: CFI = (Poccl - CVP)/(Pao - CVP). RESULTS: CPT lead to an increase in Pao from 98 +/- 14 to 105 +/- 15 mm Hg (p = 0.002). Without and with CPT, CFI increased during occlusion from 14% +/- 10% to 16% +/- 10% (p = 0.03) and from 17% +/- 9% to 19% +/- 9% (p = 0.006), respectively, relative to normal flow. During CPT, CFI was significantly higher at the beginning as well as at the end of the occlusion compared to identical instants without CPT. CFI at the end of the control occlusion did not differ significantly from the CFI at the beginning of occlusion with CPT. CONCLUSIONS: During balloon occlusion, collateral flow increased due to collateral recruitment independent of external sympathetic stimulation. Sympathetic stimulation using CPT additionally augmented collateral flow. The collateral-flow-increasing effect of CPT is comparable to the recruitment effect of the occlusion itself. This may reflect a coronary collateral vasodilation mediated by the sympathetic nervous system.

Aged↗
PubMed2001

Combined percutaneous pulmonary valvuloplasty and atrial septal defect closure for pulmonary valvular stenosis and associated secundum atrial septal defect in an adult.

Percutaneous balloon valvuloplasty is the treatment of choice for congenital pulmonary valve stenosis, and percutaneous closure of secundum atrial septal defects has become a promising alternative to surgery in selected patients. We report a case of combined percutaneous pulmonary valvuloplasty and secundum atrial septal defect occlusion in an adult patient.

Adult↗
PubMed2001

Frequency distribution of collateral flow and factors influencing collateral channel development. Functional collateral channel measurement in 450 patients with coronary artery disease.

OBJECTIVES: We sought to determine the pathogenetic predictors of collateral channels in a large cohort of patients with coronary artery disease (CAD). BACKGROUND: The frequency distribution of collateral flow in patients with CAD is unknown. Only small qualitative studies have investigated which factors influence the development of collateral channels. METHODS: In 450 patients with one- to three-vessel CAD undergoing percutaneous transluminal coronary angioplasty (PTCA), collateral flow was measured. A collateral flow index (CFI; no unit) expressing collateral flow relative to normal anterograde flow was determined using coronary wedge pressure or Doppler measurements through sensor-tipped PTCA guide wires. Frequency distribution analysis of CFI and univariate and multivariate analyses of 32 factors, including gender, age, patient history, cardiovascular risk factors, medication and coronary angiographic data, were performed. RESULTS: Two-thirds of the patients had a CFI < 0.25 and approximately 40% of patients had a CFI < 0.15, but only approximately 10% of the patients had a recruitable CFI > or =0.4. By univariate analysis, the following were predictors of CFI > or =0.25: high levels of high-density lipoprotein cholesterol, the absence of previous non-Q-wave myocardial infarction, angina pectoris during an exercise test, angiographic indicators of severe CAD and the left circumflex or right coronary artery as the collateral-receiving vessel. Percent diameter stenosis of the lesion undergoing PTCA was the only independent predictor of a high CFI. CONCLUSIONS: This large clinical study of patients with CAD in whom collateral flow was quantitatively assessed reveals that two-thirds of the patients do not have enough collateral flow to prevent myocardial ischemia during coronary occlusion, and that coronary lesion severity is the only independent pathogenetic variable related to collateral flow.

Aged↗