Biomedical subjects

V Wiegand

Publications and source records attributed to V Wiegand.

At least 37 records · Page 2Linked to original sources

PubMed1991

[Developments in and results of coronary angioplasty (PTCA) in the years 1981-1989 exemplified by 2015 treatments].

Beginning at October, 14th, 1981 until March, 10th, 1989 2015 PTCA-treatments on 1673 patients were performed in Göttingen. 2357 coronary lesions were treated, indicating an average of 1.17 lesions per treatment. During the observation period 1981 to 1986 versus 1987 to 1989 the subgroup of patients greater 65 years increased from 13.5% to 18.4% (p less than 0.01), while those patients with multivessel disease increased from 37% to 56% (p less than 0.001). During the compared observation periods the clinical success rate (all stenoses attempted greater than or equal to 20% reduced, no untowards events) was almost unchanged with 69%, versus 72%, respectively (p = n.s.). However, the rate of untowards events such as bypass grafting during the first 48 hours period decreased from 9.9% to 4.9% (p less than 0.001), the myocardial infarction rate decreased from 4.6% to 3.3% while the lethality rate stayed steadily low at 0.4%. Those nine years experience demonstrate in spite of older and sicker patients that the complication rate of PTCA procedures decreased while the success rate remained unchanged, a trend opposed to the development in coronary bypass grafting, where the complication rate increases due to older and sicker patients.

Age Factors↗

PubMed1991

[Intravascular sonography of the coronary vessels following percutaneous transluminal angioplasty].

Intravascular ultrasound imaging was performed in 15 patients (three women and 12 men; mean age 55 [48-70] years) after percutaneous balloon angioplasty of the right coronary artery (7 patients), the anterior interventricular branch (6) or the circumflex branch of the left coronary artery (2). The catheter, external diameter 4.8 F, was advanced over a 0.014--in coronary wire to the area of the previously balloon-dilated stenosis. Vessel diameter measured by ultrasound correlated closely with that by angiography (r = 0.93; P less than 0.001). Ultrasound imaging distinguished between concentric and eccentric intimal thickening and made it possible to assess the consistency and degree of calcification of the wall changes. The success of angioplasty was evaluated in 10 patients. In eight, local dissection was revealed, but only three of them had been diagnosed angiographically. In one patient a vessel spasm was recorded during ultrasound imaging; it regressed after the intracoronary injection of 0.2 mg nitroglycerin. There were no other complications. The method made it possible to assess in vivo the extent and consistency of atherosclerotic plaques, and it adds to the angiographic monitoring of treatment results and of complications after angioplasty.

Aged↗

PubMed1991

Morphologic change in coronary artery stenosis with the Medtronic Wiktor stent: initial results from the core laboratory for quantitative angiography.

The purpose of this study was to assess the early changes in stenosis geometry after implantation of the Medtronic Wiktor stent in human coronary arteries. Morphologic changes were evaluated by quantitative coronary angiography using automated edge detection. The hemodynamic significance of the morphologic changes were assessed by the calculation of the theoretical pressure drop across the dilated and stented stenosis derived from the Poiseuile and turbulent resistances assuming a coronary blood flow of either 0.5, 1, or 3 ml/sec. Fifty patients were studied before and immediately after stent implantation. The stented coronary artery was the left anterior descending artery in 26 patients, the circumflex artery in eight patients, and the right coronary artery in 16 patients. Stent implantation resulted in an additional increase in the minimal luminal cross-sectional area and minimal luminal diameter of the dilated vessel without changing the curvature of the stenosis. Furthermore, there was a significant reduction of the "plaque area." This was associated with a normalization of the calculated resistances to flow and pressure drop across the stenosis. To a minimal extent, recoil (0.1 +/- 0.36 mm) was observed after stent implantation.

Adult↗

PubMed1991

Initial clinical results with the Wiktor stent: a new balloon-expandable coronary stent.

The Wiktor stent, a new coronary balloon-expandable tantalum stent, was implanted in 17 patients for other wise nonmanageable occlusion after balloon angioplasty (n = 11) and for recurrent restenosis (n = 6). Stents of 3.0 to 4.0 mm were implanted (right coronary artery: n = 10, left anterior descending artery: n = 4, left circumflex artery: n = 2, venous graft: n = 1). All patients were fully anticoagulated initially with heparin followed by coumadin for 3 months and were treated with acetylsalicylic acid indefinitely. Due to its good radiopacity, the device could be placed easily without complications. Early occlusion occurred in one patient after 8 h probably due to friable atheromatous material prolapsing between the meshes of the stent. Late occlusion occurred in another patient who was admitted in cardiogenic shock after pre-hospital reanimation and was stented after occlusive disection following balloon angioplasty of an occluded right coronary artery. In this patient with severe hypoxic brain damage, reocclusion and reinfarction to which the patient finally succumbed occurred following cessation of anticoagulation. Histology demonstrated occlusive thrombosis without evidence of a neointimal covering of the stent. Another thrombotic occlusion due to inadvertent omission of anticoagulation occurred in another patient two weeks after stenting. Control angiography after 6 months in 12 patients revealed restenosis in two patients (50% and 80%). The patient with 80% restenosis of the right coronary artery and pathologic results during stress testing underwent surgical revascularization. The other patient with a 50% restenosis of the right coronary artery was managed medically as he was asymptomatic and without evidence of ischemia during stress testing.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗

PubMed1991

Intravascular ultrasound imaging of human coronary arteries after percutaneous transluminal angioplasty: morphologic and quantitative assessment.

An intravascular ultrasound catheter system was used in patients to assess the effect of percutaneous transluminal coronary angioplasty. In 14 out of 16 patients, the intravascular ultrasound catheter could be successfully advanced to the site of a previous dilatation. Qualitative assessment of the cross-sectional images revealed intimal thickening and an increase of ultrasound reflectance and calcification at atherosclerotic coronary arteries. A disruption of the obstructing plaque and evidence for local dissections (11 of 14 cases) were observed after angioplasty. The quantitative comparison between angiography and the ultrasound measurement showed a close correlation for vessel sites distant to the dilatation (r = 0.91 for vessel diameter; r = 0.86 for luminal area; p less than 0.001). After angioplasty, the quantitative evaluation of the dilated area was possible in 11 cases. The correlation of angiographic and sonographic measurements of these segments was good for the assessment of the vessel diameter (r = 0.82, p less than 0.001), but poor for the determination of the luminal area (r = 0.48, p = 0.10). This difference reflected the complex morphology of the vessel lumen after angioplasty, which would be better assessed by the cross-sectional sonographic technique than by contrast angiography. The intravascular imaging of coronary arteries provides a new and unique method to obtain information on the plaque morphology and composition, and to assess the local effects of interventional procedures and their complications.

Aged↗

PubMed1991

Excimer laser angioplasty in coronary artery disease.

The results of coronary excimer laser angioplasty were evaluated in 70 patients. Forty-five patients had laser angioplasty of coronary stenoses. Twenty-five patients in a total of 35 attempts had wire-guided laser recanalization of chronic coronary occlusions, resulting in a success rate of 71%. Immediate results in both groups demonstrated the efficacy of this technique without serious side-effects. Stenoses were reduced from 90 +/- 5% to 48 +/- 18% diameter reduction (mean +/- standard deviation) by excimer laser angioplasty. Residual stenosis in recanalized vessels after laser angioplasty was 52 +/- 19%. In slightly more than half of the patients with a residual stenosis greater than 50% after excimer laser angioplasty, subsequent balloon angioplasty was performed for further stenosis reduction. While satisfactory immediate results were achieved by excimer laser angioplasty intermediate follow-up revealed a restenosis rate in the same range as with balloon angioplasty.

Aged↗

PubMed1991

Doppler echocardiographic analysis of cardiac flow during the Mueller manoeuver.

The inspiration against a closed airway, the Mueller manoeuver, leads to a negative intrathoracic pressure. It is controversially discussed whether this is causing an augmentation of right heart murmurs. There is only limited knowledge on the temporal relationship of the negative intrathoracic pressure with right and left ventricular filling and stroke volume. To investigate this relationship, the flow through the mitral, aortic, tricuspid and pulmonary valves was studied continuously by Doppler echocardiography during a standardized Mueller manoeuver in 15 healthy subjects (age 45 +/- 10 years). Five heart beats after the initiation of the manoeuver, flow through the mitral and aortic valve decreased 12.2 +/- 7.2% (P less than 0.001) and 10.1 +/- 6.6% (P less than 0.001), respectively. A transient increase of 15.1 +/- 9.2% (P less than 0.001) in tricuspid flow was followed by a 14.3 +/- 9.8% (P less than 0.005) increase of flow through the pulmonary artery. Ten heart beats after the initiation of the Mueller manoeuver, flow through the pulmonary artery again reached baseline, while tricuspid flow remained below baseline values. In contrast to previous studies, our results indicate that the Mueller manoeuver causes a small and transient increase in right ventricular stroke volume which is unlikely to cause a marked augmentation in right heart murmurs.

Adult↗

PubMed1990

Recanalization of chronic total coronary arterial occlusions by percutaneous excimer-laser and laser-assisted angioplasty.

A low primary success and high restenosis rate after recanalization of chronic total occlusions by conventional coronary angioplasty have encouraged the application of new interventional techniques like excimer-laser angioplasty. In 39 patients with a coronary occlusion for 1 to 12 months, recanalization was attempted by laser angioplasty through a multifiber-catheter coupled to a pulsed XeCl excimer laser. After successful passage of the occlusion by a standard guidewire in 27 patients (69%), the laser catheter was advanced over the central guidewire and crossed the occlusion in 25 patients (64%). In 2 patients with unsuccessful passage of the laser catheter, the subsequent attempt with a low profile balloon catheter also failed. In 19 of the 25 patients with successful laser recanalization, the residual stenosis exceeded 50% and was therefore followed by additional balloon angioplasty. The average residual stenosis after laser was 61 +/- 17% of the vessel diameter, and after balloon angioplasty 28 +/- 9% (n = 19), whereas after laser angioplasty alone it was 38 +/- 5% (n = 6). No complications associated with the laser application were observed. Angiographic control after 24 hours showed a reocclusion of 2 (8%) recanalized vessels. In this pilot study, laser angioplasty proved to be a safe and feasible method for the treatment of chronic total coronary occlusions. Because it was necessary to guide the catheter by a central wire, the primary success was limited by a successful passage of the wire of the occlusion. The rate of stand-alone laser angioplasty has to be increased by future improvements of the technique to enable a comparative evaluation of this method with conventional angioplasty.

Angioplasty, Laser↗

PubMed1990

Enteroviral infection in end stage dilated cardiomyopathy.

In order to evaluate the role of enteroviral infections in end stage dilated cardiomyopathy, RNA was isolated from left ventricular myocardium of patients with dilated cardiomyopathy explanted during heart transplantation (n = 6) and from control hearts (n = 8), then probed using a dot blot procedure with two well-defined enteroviral cloned cDNA probes. One of the cardiomyopathic heart samples hybridized with the enteroviral probes, while RNA samples from the other diseased heart and the control heart demonstrated no hybridization. To verify further the enteroviral infection, a cDNA prepared from the positive heart RNA hybridized with Southern blotted coxsackievirus B3 and poliovirus 1 nucleotide sequences, while a control sample, which gave negative results in the dot blot, showed no hybridization to the enteroviral sequence. These results provide evidence for an enteroviral infection in certain patients with end stage dilated cardiomyopathy.

Adult↗

PubMed1990

Severe granulomatous giant cell myocarditis in Wegener's granulomatosis.

A 28-year-old male patient suffering from Wegener's granulomatosis died suddenly with signs of cardiac failure after clinical symptoms had basically subsided under chemotherapy. Autopsy revealed pulmonary granulomata, necrotizing vasculitis of the lungs and kidneys, focal and segmental necrotizing glomerulonephritis, and diffuse granulomatous and necrotizing giant cell myocarditis. Histological confirmation of inflammation of the heart in Wegener's disease has rarely been reported. Although cardiac involvement in Wegener's granulomatosis sometimes is suspected, it is usually thought to have no major impact on the course of the disease. By its dramatic clinical and morphologic presentation this case illustrates that the heart, in addition to the lungs and kidneys, may determine the outcome of the idiopathic granulomatous vasculitis of Wegener.

Adult↗

PubMed1990

[Intravascular ultrasonic diagnosis. In vivo findings before and after angioplasty in peripheral arterial occlusive disease].

In 15 patients (13 men, two women, mean age 63 [47-75] years) with peripheral arterial occlusive disease in stages IIB-IV (Fontaine) intravascular ultrasound findings were compared with the angiographic results before and after treatment. In 12 patients stenosis (n = 10) or occlusion (n = 2) of the iliac artery (n = 2) or the superficial femoral artery (n = 10) were treated by conventional balloon angioplasty; in three patients with occlusion of the superficial femoral artery excimer laser angioplasty was performed. There was good correlation between measurements of vessel diameter by the two techniques (r = 0.93, P less than 0.001). Ultrasound scanning provided additional informations regarding the thickness of the plaque, the density or firmness of the stenosis and the degree of calcification. The therapeutic outcome was quantified by measuring the gain in lumen diameter. The authors also assessed the morphological changes following angioplasty in the vicinity of the obstructing plaque. In the light of the ultrasound findings it was considered necessary to undertake further dilatation in four out of the 12 patients treated by balloon dilatation. The results indicate that intravascular ultrasound imaging is a valuable complement to angiography for monitoring of therapeutic results after vascular interventions.

Aged↗

PubMed1990

[Acute effects of the angiotensin converting enzyme inhibitor ramipril in patients with coronary heart disease].

We investigated the acute effect of the new long-acting ACE-inhibitor ramipril on angina-limited exercise tolerance and exercise-induced ST-depression in 18 normotensive patients with angiographically confirmed coronary artery disease in a double-blind, placebo-controlled study. Patients underwent a repeat exercise ECG 24 hours following either 5 mg ramipril p.o. or placebo. Plasma-ACE activity (nmol/min x ml) in the ramipril-group (n = 8) was significantly reduced 24 hours after 5 mg ramipril compared to placebo (n = 10): 14.0 +/- 2.0 vs 87.2 +/- 13.5, p less than 0.001. Exercise-induced ST-segment depression was not different before and after ramipril or placebo. Heart rate at rest and during angina-limited exercise was not different between the first exercise-ECG and that after ramipril or placebo, nor between the groups. Systolic arterial pressure (mmHg) was slightly, but insignificantly, lower after than before ramipril at rest (113.8 +/- 5 vs 125 +/- 6.8) and at maximal exercise, 1.5 watt/kg (150 +/- 9.4 vs 158.3 +/- 13.3). In the placebo group, blood pressure at rest and during exercise was not different before and after placebo: 126 +/- 4.7 vs 125.5 +/- 7.5 and 157.5 +/- 3.8 vs 158 +/- 3.6. Rate-pressure-product (mmHg/min x 1000) at rest prior to (8.42 +/- 0.83 and 8.95 +/- 0.51) and after ramipril or placebo (8.00 +/- 0.94 and 8.93 +/- 0.71) showed no significant difference. Similarly, rate-pressure-product at maximal exercise was equal among the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1990

Malignant restenosis after primary successful excimer laser coronary angioplasty.

In a series of 20 coronary excimer laser angioplasties, two patients presented with a peculiar type of malignant restenosis 6 and 8 weeks after a successful laser angioplasty procedure. One patient had a successful recanalization of an occluded left anterior descending (LAD) coronary artery and the second patient had a successful angioplasty of a subtotal proximal stenosis of the left anterior descending coronary artery. After the procedure, no ischemia could be demonstrated by exercise ECG and thallium scintigraphy. Both patients were free of angina until the sudden development of nocturnal angina several hours before reangiography, which showed subtotal restenosis in both cases. One patient had a mammaria graft on the LAD and the second patient underwent a successful balloon angioplasty. This uncommon sudden and malignant development of restenosis seems to be related to the excimer laser angioplasty procedure and warrants some caution with the indiscriminative use of this new angioplasty procedure.

Aged↗

PubMed1990

Impaired relationship between Doppler echocardiographic parameters of diastolic function and left ventricular filling pressure during acute ischemia.

The relationship between left ventricular filling pressure and Doppler echocardiographic parameters of diastolic mitral flow (MF) was evaluated in patients with ischemic heart disease during acute ischemia induced by percutaneous transluminal coronary angioplasty (PTCA) of the left anterior descending artery. Thirty-two patients were examined by simultaneous recordings of the Doppler MF signal and the mean pulmonary capillary wedge pressure (PCm) as an approximation of left ventricular filling pressure. At rest PCm was correlated with the early/late velocity integral ratio (Ei/Ai: r = 0.62: p less than 0.0001; n = 32). In 25 of 32 patients the recordings during PTCA could be evaluated. At the end of the inflation (duration: 69 +/- 24 seconds) PCm increased from 11.2 +/- 5.5 to 17.2 +/- 7.2 mm Hg (p less than 0.001), and total MF integral as an index of systolic ventricular function decreased by 14.9 +/- 12.8% (p less than 0.001). Inasmuch as both early and late velocity integrals were reduced during PTCA, the Ei/Ai ratio did not change significantly (1.41 +/- 0.51 to 1.34 +/- 0.60; NS). In a subgroup of inflations without ECG signs of ischemia, Ei was decreased without a concomitant decrease in Ai, thus leading to a decrease in the Ei/Ai ratio (1.36 +/- 0.43 to 1.17 +/- 0.31; p less than 0.05). Summarizing the events during PTCA, a steady increase in PCm was observed, whereas the Ei/Ai ratio was slightly decreased. Thus the observation at rest that an elevated PCm was associated with an elevated Ei/Ai was no longer valid during PTCA (Ei/Ai: r = 0.28; NS). A significant correlation was found between parameters of Doppler MF and PCm in patients with ischemic heart disease at rest. During PTCA this relationship was attenuated. Therefore noninvasive assessment of left ventricular filling pressures during acute ischemia by Doppler echocardiography does not seem feasible.

Adult↗

PubMed1990

Molecular approaches to enteroviral diagnosis in idiopathic cardiomyopathy and myocarditis.

Enteroviruses are thought to be etiologic agents in some cases of human myocarditis and dilated cardiomyopathy. Murine models of acute coxsackievirus B3 myocarditis implicate coxsackie B viruses as possible causes of human myocarditis. Indirect evidence implicating enteroviruses as causative agents in human heart disease derives from serologic studies. More recently, direct evidence for enteroviral presence in diseased human heart tissues has been obtained by nucleic acid hybridization analyses. Although the data suggest that enteroviral infections may be associated with 18% to 50% of cases of myocarditis or dilated cardiomyopathy, or both, causality has not been established. Unanswered questions remain regarding the specific identity of the enteroviral genomes detected in the human heart and the potential for enteroviruses to persist in the heart.

Cardiomyopathies↗

PubMed1990

Effect of acetylcholine on arterial and venous grafts and coronary arteries in patients with coronary artery disease.

Endothelium-dependent vasomotor responses differ in arteries and veins. The transfer of a given vessel from a different vascular bed into the coronary circulation by grafting may affect its endothelial function. In order to evaluate the differences in endothelial function of the internal mammary artery and aortocoronary venous grafts in patients with coronary artery disease, the response to acetylcholine (ach) was examined and compared with that of native coronary arteries. Eighteen patients were examined, including eight with internal mammary artery grafts (9 days to 48 months after surgery), and 10 with saphenous vein grafts (12-96 months after surgery). Ach (70-700 nmol min-1) was infused selectively into a graft on the left anterior descending coronary artery, and the effect on vessel diameters was assessed by quantitative arteriography. In both groups 84% and 83%, respectively, of the arterial segments distal to the bypass anastomosis were contracted by ach (greater than or equal to 70 nmol min-1). The segments of both groups did not show angiographic evidence of local atherosclerosis. A complete occlusion occurred in four cases. In contrast, internal mammary artery grafts were not contracted by ach; in four of 12 segments a dilatation was observed, whereas five of 20 aortocoronary venous graft segments showed a slight reduction in lumen diameter after the highest ach dose applied. The vasoconstricting effect of ach was reversed by intracoronary nitroglycerin. By using ach as an indicator of endothelial dysfunction it is concluded that the internal mammary artery grafts maintained an intact endothelial function after surgery, whereas the coronary artery segments showed an impaired endothelium-dependent vasodilatation. Some of the venous graft segments reacted as coronary arteries did with a less pronounced cholinergic vasoconstriction. This in vivo study supports the observation of a functional superiority of internal mammary artery over saphenous vein coronary grafts.

Acetylcholine↗

PubMed1990

Alterations of the mitochondrial respiratory chain in human dilated cardiomyopathy.

The defects underlying the impairment of systolic pump function in human dilated cardiomyopathy (DCM) are not known. We isolated mitochondrial particles from 10 hearts of transplant recipients with DCM and from nine normal hearts not used for transplantation. Yield was similar in both groups (2.77 vs 2.81 mg mitochondrial protein per gram heart). Cytochrome content (difference spectrophotometry) was found reduced in DCM mitochondria, e.g. cytochrome c was 0.295 +/- 0.06 in the DCM group and 0.371 +/- 0.04 mumol g-1 in the control group (P less than 0.05). Enzymatic activity of the cytochrome-containing complexes III (3.77 +/- 0.82 vs 4.95 +/- 1.15 mumol min-1.mg-1) and IV (2.63 +/- 0.96 vs 3.65 +/- 0.6 mumol min-1.mg-1) of the respiratory chain was reduced in the DCM group (P less than 0.05). Complex IV, the cytochrome c oxidase, in the DCM group showed impaired activity also in whole heart homogenates (0.173 +/- 0.04 vs 0.258 +/- 0.8 mumol min-1.mg-1). Subunit composition of the cytochrome c oxidase on sodium dodecyl sulphate-gel electrophoresis did not differ between DCM and normal hearts. Activity of complexes II and V of the respiratory chain, not containing cytochromes, was unchanged in DCM mitochondria compared with the control group. The present data show a decrease in cytochrome content and in cytochrome-dependent enzyme activity in human dilated cardiomyopathy. Further studies are necessary to clarify whether these findings are specific for dilated cardiomyopathy or whether they are epiphenomena of failing hearts.

Apyrase↗

PubMed1990

[Acute hemodynamic effects of the vasodilator beta blocker carvedilol in heart failure].

The beta-blocker carvedilol has been shown to induce vasodilation in patients with coronary artery disease. In a double-blind, randomized, placebo-controlled cross-over study, we looked for the acute vasodilating effect after i.v. administration in patients with heart failure. In 10 patients with coronary artery disease and six patients with dilated cardiomyopathy, all with an ejection fraction lower than 40%, the rate-pressure-product during supine ergometry and Swan-Ganz-catheterization rose to a significantly smaller extent after 5 mg carvedilol i.v. compared to placebo. This was mainly due to a lower heart rate at rest and during exercise, while blood pressure was not changed compared to placebo. Calculated total peripheral resistance during exercise after carvedilol was higher--significantly so in the CAD-group--than after placebo. These results show that in patients with heart failure, an acute vasodilating effect of i.v. carvedilol is not detectable.

Adrenergic beta-Antagonists↗