Biomedical subjects

M Fleisch

Publications and source records attributed to M Fleisch.

At least 19 recordsLinked to original sources

PubMed2003

Expression of the hyaluronan receptor RHAMM in endometrial carcinomas suggests a role in tumour progression and metastasis.

PURPOSE: Interactions of hyaluronic acid (HA) with its binding protein RHAMM (receptor for HA-mediated motility) have been proposed as being important in promoting tumour progression and dissemination. This comparative study was designed to investigate the RHAMM expression patterns in endometrial carcinoma. METHODS: We examined a series of 89 endometrial carcinomas and 15 normal endometrial tissues by immunohistochemistry, using a RHAMM-specific polyclonal antibody. Expression of RHAMM was assessed according to the pattern and intensity within (overall cytoplasm, center/periphery of tumours) and between the tumours. The staining results were compared to the corresponding clinical data (age, menopause status, histological staining, histological grading, lymph node status). RESULTS: RHAMM-expression was detectable in 58% of the 89 tumours [Histological stage: pT1a (8/12); pT1b (16/37); pT1c (18/26); pT2 (6/9); pT3a (4/5)] and 13% (2/15) of the normal endometrial tissues. The positivity rates for RHAMM were 100% in patients with positive lymph nodes but only 50.7% in patients with negative lymph nodes ( P<0-01). Additionally, the expression pattern showed a highly significant correlation ( P<0.01) with the histological grade of the tumours [G1 (6/42), G2 (33/34), G3 (13/13)] and occurrence of lymph node metastases. CONCLUSIONS: Our results suggest that RHAMM expression may enhance and improve the invasion and metastasis of endometrial carcinomas.

Adenocarcinoma, Clear Cell↗

PubMed2001

Collateral and collateral-adjacent hyperemic vascular resistance changes and the ipsilateral coronary flow reserve. Documentation of a mechanism causing coronary steal in patients with coronary artery disease.

OBJECTIVES: The goal of this clinical study was to assess the influence of hyperemic ipsilateral, collateral and contralateral vascular resistance changes on the coronary flow velocity reserve (CFVR) of the collateral-receiving (i.e. ipsilateral) artery, and to test the validity of a model describing the development of collateral steal. METHODS: In 20 patients with one- to two-vessel coronary artery disease (CAD) undergoing angioplasty of one stenotic lesion, adenosine induced intracoronary (i.c.) CFVR during vessel patency was measured using a Doppler guidewire. During stenosis occlusion, simultaneous i.c. distal ipsilateral flow velocity and pressure (P(occl), using a pressure guidewire) as well as contralateral flow velocity measurements via a third i.c. wire were performed before and during intravenous adenosine. From those measurements and simultaneous mean aortic pressure (P(ao)), a collateral flow index (CFI), and the ipsilateral, collateral, and contralateral vascular resistance index (R(ipsi), R(coll), R(contra)) were calculated. The study population was subdivided into groups with CFI<0.15 and with CFI> or =0.15. RESULTS: The percentage-diameter coronary artery stenosis (%-S) to be dilated was similar in the two groups: 78+/-10% versus 82+/-12% (NS). CFVR was not associated with %-S. In the group with CFI> or =0.15 but not with CFI<0.15, CFVR was directly and inversely associated with R(coll) and R(contra), respectively. CONCLUSIONS: A hemodynamic interaction between adjacent vascular territories can be documented in patients with CAD and well developed collaterals among those regions. The CFVR of a collateralized region may, thus, be more dependent on hyperemic vascular resistance changes of the collateral and collateral-supplying area than on the ipsilateral stenosis severity, and may even fall below 1.

Adenosine↗

PubMed2001

The value of intraoperative angiography in surgery of intracranial aneurysms: a prospective study in 126 patients.

The value of intraoperative digital subtraction angiography in surgery for intracranial aneurysms, the benefits and cost-effectiveness are a matter of discussion. We prospectively studied 126 patients with 144 aneurysms, most on the anterior intracranial circulation, who underwent clipping and intraoperative angiography. Follow-up was 28.4 +/- 13.1 months. We tried to work out the indications for intraoperative angiography of the anterior circulation and its cost-effectiveness. In 10.3 % of patients (9 % per aneurysm) unexpected findings were shown by intraoperative angiography: inadequately clipped aneurysms in 10 (7.9 %), a completely unclipped aneurysm in one (0.8 %) and occluded major arteries in two (1.6 %). A broad neck was a variable of statistical significance for inadequate clipping or stenosis or occlusion of an adjacent vessel. There was a strong trend for aneurysms more than 15 mm in diameter to be "risky". Their site was not a predictive factor. We believe that intraoperative angiography is indicated in surgery not only on large and giant aneurysms, but also broad-based aneurysms of the anterior cerebral circulation regardless of their size. It is cost-effective compared to postoperative angiography. The rate of stroke in our hands was 0.8%.

Adult↗

PubMed2001

Do beta-adrenergic blocking agents increase coronary flow reserve?

BACKGROUND: Beta-adrenergic blocking agents are the cornerstone in the treatment of coronary artery disease (CAD). The exact pathophysiologic mechanism is not clear but depends largely on the oxygen-sparing effect of the drug. Thus, the effect of metoprolol on coronary flow reserve and coronary flow velocity reserve (CFVR) was determined in patients with CAD. METHODS: Coronary blood flow velocity was measured with the Doppler flow wire in 23 patients (age: 56 +/- 10) undergoing percutaneous transluminal coronary angioplasty for therapeutic reasons. Measurements were carried out at rest, after 1-min vessel occlusion (postischemic CFVR) as well as after intracoronary adenosine (pharmacologic CFVR) before and after 5 mg intravenous metoprolol. In a subgroup (n = 15), absolute flow was measured from coronary flow velocity multiplied by coronary cross-sectional area. RESULTS: Rate-pressure product decreased after metoprolol from 9.1 to 8.0 x 10(3) mm Hg/min (p < 0.001). Pharmacologic CFVR was 2.1 at rest and increased after metoprolol to 2.7 (p = 0.002). Likewise, postischemic CFVR increased from 2.6 to 3.3 (p < 0.001). Postischemic CFVR was significantly higher than pharmacologic CFVR before as well as after metoprolol. Coronary vascular resistance decreased after metoprolol from 3.4 +/- 2.0 to 2.3 +/- 0.7 mm Hg x s/cm (p < 0.02). CONCLUSIONS: The following conclusions were drawn from this study. Metoprolol is associated with a significant increase in postischemic and pharmacologic CFVR. However, postischemic CFVR is significantly higher than pharmacologic CFVR. The increase in CFVR by metoprolol can be explained by a reduction in vascular resistance. The increase in CFVR (= increased supply) and the reduction in oxygen consumption (= decreased demand) after metoprolol explain the beneficial effect of this beta-blocker in patients with CAD.

Adrenergic beta-Antagonists↗

PubMed2001

Peritoneal dialysis fluids with a physiologic pH based on either lactate or bicarbonate buffer-effects on human mesothelial cells.

Conventional lactate (Lac)-buffered peritoneal dialysis (PD) solutions have turned out to be detrimental to human peritoneal cells, especially because of a low pH. In the present study, we focus on potential differences between Lac and bicarbonate (Bic) as a buffer when adjusted to a physiological pH. All test fluids were buffered with either 40 mmol/L of Lac or 34 mmol/L of Bic, sterile filtered, and adjusted to a pH of 7.4. Osmotic agents used were 1.36% glucose (Glu), 3.86% Glu, 1% amino acids (AA), and 7.5% Glu polymer (Glupoly). Human peritoneal mesothelial cells (HPMCs) were isolated from the omentum majus, grown to confluence, and incubated after the second passage for 15 minutes (37 degrees C and 5% carbon dioxide) with the test fluids. Cytotoxicity was controlled by measuring apoptotic and necrotic cells with cytofluorometry. Aerobic cell metabolism (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide [MTT] assay) and intracellular adenosine triphosphate (ATP) concentrations were measured to assess cell viability. Release of interleukin-6 (IL-6) from HPMCs was determined as a parameter of cellular host defense. No significant difference in apoptosis or necrosis rates was found between the solutions adjusted to normal pH. However, in the MTT assay, Bic solutions were superior to corresponding Lac pendants at an identical pH of 7.4 (P < 0.01). Intracellular ATP concentrations reflected a very similar pattern (P < 0.05). Glupoly in combination with Lac showed an impaired pattern with both the MTT and ATP assays. Regarding IL-1beta-stimulated IL-6 release, there was a small, but not significantly better, response for Bic. Differences in manifest cell cytotoxicity reflected by apoptosis and necrosis rates could not be detected comparing PD solutions buffered with Lac or Bic at a physiological pH. However, distinct parameters of cell metabolism were superior with Bic compared with Lac. Especially Glupoly was inferior in combination with Lac as a buffer.

Adenosine Triphosphate↗

PubMed2001

[Advanced breast biopsy instrumentation (ABBI) experiences and critical comments].

UNLABELLED: Advanced breast biopsy instrumentation (ABBI) experiences and critical comments. PURPOSE: To describe our three-years' experience with advanced breast biopsy instrumentation (ABBI). MATERIALS AND METHODS: Considering lesion size, type and location as well as patient specific criteria 89 patients were selected for an ABBI. The documented data like duration, complication and change of the procedure, size of the lesions and biopsy cannulas, histologic outcome and further treatment were analysed retrospectively. RESULTS: ABBI was successful in 63 of 89 patients. Cancer was found in 18 patients (29 %) with a surgical re-excision to achieve tumour-free margins in 89 %. 45 patients had benign lesions (71 %) with a benign to malignant ratio of 2.5 : 1. ABBI was unsuccessful or had to be replaced by other biopsy techniques in 26 patients (29 %). In four of these patients the localization needle was already placed. Analysing the three-year period ABBI frequency dropped each year with an overall reduction of 63 %. Despite a good benign to malignant ratio the surgical re-excision rate in cancer patients is disappointing. Although using precise selection criteria for ABBI the rate of failed biopsies and changeover to another biopsy procedure was too high. The reduction of ABBI procedures during the three-year period is assumed to be an expression of the negative experiences with the method but also a refusal of the assigning colleagues to use ABBI. CONCLUSION: For the evaluation of suspected breast lesions ABBI is too invasive and too expensive. On the other hand ABBI is too ineffective as a therapeutic tool to remove suspected lesions. Therefore it is not warranted to use ABBI instead of other concurrent biopsy techniques.

Adult↗

PubMed2001

[Practical usage of a quality management system according to ISO 9001 : 2000 focusing on the double contrast (barium) enema].

PURPOSE: We describe the implementation of quality improvement measures in a quality management system. METHODS: With questionnaires for radiologists and patients, we investigated the relations between patient preparation and diagnostic quality serving the main purpose, to improve diagnostic quality with the help of more detailed patient information (e.g., changing preparation sheets and handling out "peri-med" information sheets to the patients). Furthermore, a comparative data ascertainment at other institutes was integrated. RESULTS: For the group of outpatients, increasing process quality (patient information) and outcome (diagnostic quality) could be achieved. Taking aspects of quality costs into consideration, a decrease in costs due to failures was achieved. CONCLUSION: More detailed patient information has positive effects on diagnostic quality of the double contrast (barium) enema.

Attitude of Health Personnel↗

PubMed2001

Quantitative contrast echocardiographic assessment of collateral derived myocardial perfusion during elective coronary angioplasty.

OBJECTIVE: To determine whether myocardial contrast echocardiography can be used to quantify collateral derived myocardial flow in humans. METHODS: In 25 patients undergoing coronary angioplasty, a collateral flow index (CFI) was determined using intracoronary wedge pressure distal to the stenosis to be dilated, with simultaneous mean aortic pressure measurements. During balloon occlusion, echo contrast was injected into both main coronary arteries simultaneously. Echocardiography of the collateral receiving myocardial area was performed. The time course of myocardial contrast enhancement in images acquired at end diastole was quantified by measuring pixel intensities (256 grey units) within a region of interest. Perfusion variables, such as background subtracted peak pixel intensity and contrast transit rate, were obtained from a fitted gamma variate curve. RESULTS: 16 patients had a left anterior descending coronary artery stenosis, four had a left circumflex coronary artery stenosis, and five had a right coronary artery stenosis. The mean (SD) CFI was 19 (12)% (range 0-47%). Mean contrast transit rate was 11 (8) seconds. In 17 patients, a significant collateral contrast effect was observed (defined as peak pixel intensity more than the mean + 2 SD of background). Peak pixel intensity was linearly related to CFI in patients with a significant contrast effect (p = 0.002, r = 0.69) as well as in all patients (p = 0.0003, r = 0.66). CONCLUSIONS: Collateral derived perfusion of myocardial areas at risk can be demonstrated using intracoronary echo contrast injections. The peak echo contrast effect is directly related to the magnitude of collateral flow.

Aged↗

PubMed2001

Influence on collateral flow of recanalising chronic total coronary occlusions: a case-control study.

OBJECTIVE: To assess the effect of recanalisation on collateral flow in a case-control study in patients with and without chronic total coronary occlusions. DESIGN: In 54 patients undergoing percutaneous transluminal coronary angioplasty (PTCA) (mean (SD) age 61 (6) years), coronary collateral flow was measured by intracoronary pressure or Doppler guide wires at the end of repeated balloon occlusions. Coronary collateral flow index (collateral flow relative to normal antegrade flow) during the first two balloon inflations in 27 patients with a chronic total occlusion (occlusion group) was compared with that of 27 patients matched for age, sex, and collateral flow index at the first occlusion and with a coronary artery diameter stenosis </= 80% (stenosis group). RESULTS: Following revascularisation, collateral flow index decreased in 17 of the patients in the occlusion group (63%) and in eight of the patients in the stenosis group (30%) (p = 0.03 between groups). The overall change of collateral flow index between the first and the second balloon occlusion was -0.04 (0.01) in the occlusion group (p = 0.07 for paired comparison; from 0.29 (0.17) to 0.25 (0.14)), and +0.02 (0.06) in the stenosis group (p = 0.06 for paired comparison; from 0.27 (0.13) to 0.30 (0.15)). The trend to collateral enhancement in the stenosis group differed significantly from the occlusion group (p = 0.01). CONCLUSIONS: While repeated coronary balloon occlusions induce collateral recruitment in the majority of patients with moderate stenoses, recanalisation of chronic total coronary occlusions is more often associated with collateral flow reduction. A later decrease in collateral flow by involution of collateral channels cannot be excluded by this study but has not been reported so far.

Angioplasty, Balloon, Coronary↗

PubMed2001

Washout collaterometry: a new method of assessing collaterals using angiographic contrast clearance during coronary occlusion.

OBJECTIVE: To investigate the hypothesis that the time to washout of radiographic contrast medium trapped distal to an occluded collateral receiving vessel is inversely related to collateral flow, and that this provides an accurate method for characterising coronary collaterals. METHODS: An intracoronary pressure derived collateral flow index was determined in 54 patients undergoing percutaneous transluminal coronary balloon angioplasty (PTCA). The study group was subdivided according to whether the collateral vessels were sufficient (n = 17) or insufficient (n = 37) to prevent ECG signs of myocardial ischaemia during PTCA. Washout collaterometry-an angiographic washout method-was carried out simultaneously; after injection of radiographic contrast medium into the collateral receiving vessel followed immediately by vascular occlusion, the number of heart beats was counted until approximately half the length of the epicardial vessel was cleared of contrast. RESULTS: The collateral flow index was higher (0.28 (0.09) v 0.12 (0.07); p < 0.0001) and the contrast washout time shorter (8.0 (2.9) v 17.5 (6.7) heart beats; p < 0.0001) in patients with sufficient versus insufficient collaterals. There was an inverse correlation between contrast washout time and collateral flow index (r = 0.72, p < 0.0001). Washout of contrast distal to the occluded vessel within 11 heart beats correctly determined sufficient and insufficient collaterals with 88% sensitivity and 81% specificity. CONCLUSIONS: Washout collaterometry is a new radiographic contrast washout method based on the inverse relation between collateral flow and the time to clearance of radiographic dye injected into the ipsilateral vessel during PTCA. It appears to be an accurate method of characterising coronary collateral vessels.

Angioplasty, Balloon, Coronary↗

PubMed2000

Quantitatively assessed coronary collateral circulation and restenosis following percutaneous revascularization.

AIMS: A high degree of collateral supply to a vascular area where a percutaneous transluminal coronary angioplasty (PTCA) has been performed represents a haemodynamic force competing with the antegrade flow through the dilated lesion. Therefore, our purpose was to determine whether patients with restenosis following PTCA have a higher collateral flow to the recipient vessel than patients without restenosis. METHODS AND RESULTS: In 200 consecutive PTCA patients, an intracoronary pressure-derived collateral flow index (CFI) was determined quantitatively during balloon occlusion, using simultaneous measurements of the mean aortic pressure (P(ao)) and of the intracoronary pressure distal to the occluded stenosis (P(occl)), as well as the estimated central venous pressure (CVP=5 mmHg): CFI=(P(occl)-CVP)/(P(ao)-CVP). Sixty-four patients had an angiographic follow-up examination after at least 2 months, and were subdivided into patients with restenosis (>50% diameter stenosis, n=34) and patients without restenosis (n=30). Patients with restenosis had a significantly higher collateral flow index at the initial coronary angiography than patients without restenosis (0.26 +/- 0.14 vs 0.12 +/- 0.09; P<0.0001). CONCLUSIONS: Patients with restenosis after PTCA show a more extended collateral supply to this recipient area than patients without restenosis. Well developed collaterals to a revascularized region are a risk factor for restenosis of the treated lesion.

Adult↗

PubMed2000

[Implementation of the quality management system ISO/CD2 9001-2000 in a radiology institute].

Quality assurance in health care, a relatively new discipline, has developed rapidly over the last years and is now required by law. The Quality Management System (QMS) ISO 9001 aims at the definition of requirements necessary in order to achieve perfect products and continuous quality improvement. Implementation of this QMS necessitates the analysis and written documentation of all working processes and modes of operation. Furthermore, potential improvement possibilities are defined to guarantee highly qualified, generally applicable and standardised procedures. Time-consuming data assessment is an instrument to enable disclosure and analysis of existing errors as well as to show possibilities of optimization, thus forming the basis for continuous improvement. The new ISO NORM 9001-2000 is process-orientated with an organisational structure strongly recommendable for service institutions and therefore also for a department of radiology.

Academies and Institutes↗

PubMed2000

Tetrahydrobiopterin improves endothelial function in patients with coronary artery disease.

Tetrahydrobiopterin (BH4) is an essential cofactor for nitric oxide synthase (NOS) and a scavenger of oxygen-derived free radicals. Decreased availability of BH4 leads, under in vitro conditions, to reduced nitric oxide (NO) production and increased superoxide formation. We studied the effect of exogenous BH4 on endothelial function of angiographically normal vessel segments in patients with coronary artery disease. Nineteen patients with coronary artery disease underwent quantitative coronary angiography with simultaneous coronary flow velocity measurements (Cardiometrics FloWire). Data were obtained in angiographically normal segments of the left coronary artery at baseline, after intracoronary (i.c.) administration of acetylcholine (Ach; 10(-4) M), after infusion of BH4 (10(-2) M), and after co-infusion of ACh and BH4. At the end of the study, 300 microg nitroglycerin (NTG) i.c. was administered to obtain maximal vasodilation. At each step, flow velocity was determined before and after 18 microg adenosine i.c. to assess coronary flow velocity reserve. In 15 patients, ACh induced coronary vasoconstriction of -18 +/- 3% (endothelial dysfunction; p < 0.0001 vs. baseline), and in four patients, vasodilation of +39 +/- 20%. In the 15 patients with endothelial dysfunction, BH4 alone did not influence vessel area but prevented vasoconstriction to ACh (+2 +/- 3%, NS, vs. baseline). Correspondingly, calculated volume flow showed the highest value after co-infusion of ACh and BH4. Coronary flow velocity reserve was comparable during the various infusion steps. BH4 prevents ACh-induced vasoconstriction of angiographically normal vessels in patients with coronary artery disease. Thus substitution of this cofactor of NOS may represent a new approach for the treatment of endothelial dysfunction.

Acetylcholine↗

PubMed2000

Systemic, pulmonary, and renal hemodynamic effects of endothelin ET(A/B)-receptor blockade in patients with maintained left ventricular function.

Endothelin-1 (ET-1) regulates vascular tone in congestive heart failure and modulates renal function. Its role in patients with normal left ventricular (LV) function and its renal effects are unclear. Cardiac and renal hemodynamics were studied in 24 patients with normal LV function and coronary arteries after single-dose, double-blind, randomized administration of TAK-044 (25, 50, or 100 mg, i.v.), an ET(A/B)-receptor antagonist, or placebo. Hemodynamics were monitored using Swan-Ganz and arterial catheters, and ET levels were measured. Renal function was assessed by clearance techniques. In the absence of a dose-response relation, TAK-044 patients were analyzed as a single group. Most hemodynamic effects occurred during the first 4 h. TAK-044 reduced mean arterial (-9.3 mm Hg, p < 0.001), pulmonary (-1.8 mm Hg, p = 0.01), and pulmonary capillary wedge pressure (-1.6 mm Hg, p < 0.001) between 30 min and 4 h. Mean reduction in systemic vascular resistance was 279 dyne/s/cm2 (p < 0.001), whereas heart rate increased 6.1 beats/min (p < 0.001) and cardiac index by 0.37 L/m2 (p = 0.01). Stroke volume index, right atrial pressure, and pulmonary vascular resistance did not change. TAK-044 increased renal plasma flow in proportion to the increase in cardiac output (+119 ml/min, 4 h after TAK-044; p < 0.05) and ET-1 levels (2.5-fold; p < 0.05). No serious side effects were noted. In patients with normal cardiac function, ET-receptor blockade causes vasodilation and reduces systemic but not pulmonary vascular resistance and increases cardiac index and renal plasma flow.

Aged↗

PubMed1999

Physiologically assessed coronary collateral flow and intracoronary growth factor concentrations in patients with 1- to 3-vessel coronary artery disease.

BACKGROUND: The purpose of this study was to test the hypothesis that there is a relation between collateral flow and intracoronary concentrations of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) and that the combined concentrations of both growth factors and the extent of coronary artery disease (CAD) play a role as covariables in such an association. METHODS AND RESULTS: In 76 patients undergoing balloon angioplasty, a collateral flow index (CFI, no units) was determined with sensor-tipped guidewires. Simultaneously, serum concentrations of bFGF and VEGF, obtained at the aortic root from the ostium of the collateralized coronary artery (n = 76) and from the distal position of the occluded coronary artery (n = 34), were determined. There was a direct correlation between CFI and distal VEGF (r = 0.33, P = 0.05) but not bFGF concentrations. Focusing on the proximal sampling site, there was a direct correlation between CFI and both bFGF (r = 0.29, P = 0.01) and VEGF concentrations (r = 0.44, P < 0.0001). The sum of the concentrations of both growth factors was directly associated with CFI irrespective of the proximal (r = 0.51, P < 0.0001) or distal sampling site (r = 0.34, P = 0.048). There was a trend toward higher proximal VEGF concentrations in patients with higher numbers of coronary stenotic lesions (r = 0.25, P = 0.03). CONCLUSIONS: In patients with CAD, there is an association between a directly measured index of collateral flow and intracoronary concentrations of bFGF and VEGF. This direct relation is dependent on the site of blood sampling within the coronary artery tree. The association is closest when the combined bFGF and VEGF concentrations are taken into account. In the case of VEGF, it is influenced by the degree of coronary atherosclerosis.

Arteriosclerosis↗

PubMed1999

Is the development of myocardial tolerance to repeated ischemia in humans due to preconditioning or to collateral recruitment?

OBJECTIVES: The purpose of this study in patients with quantitatively determined, poorly developed coronary collaterals was to assess the contribution of ischemic as well as adenosine-induced preconditioning and of collateral recruitment to the development of tolerance against repetitive myocardial ischemia. BACKGROUND: The development of myocardial tolerance to repeated ischemia is nowadays interpreted to be due to biochemical adaptation (i.e., ischemic preconditioning). METHODS: In 30 patients undergoing percutaneous transluminal coronary angioplasty, myocardial adaptation to ischemia was measured using intracoronary (i.c.) electrocardiographic (ECG) ST segment elevation changes obtained from a 0.014-in. (0.036 cm) pressure guidewire positioned distal to the stenosis during three subsequent 2-min balloon occlusions. Simultaneously, an i.c. pressure-derived collateral flow index (CFI, no unit) was determined as the ratio between distal occlusive minus central venous pressure divided by the mean aortic minus central venous pressure. The study patients were divided into two groups according to the pretreatment with i.c. adenosine (2.4 mg/min for 10 min starting 20 min before the first occlusion, n = 15) or with normal saline (control group, n = 15). RESULTS: Collateral flow index at the first occlusion was not different between the groups (0.15 +/- 0.10 in the adenosine group and 0.13 +/- 0.11 in the control group, p = NS), and it increased significantly and similarly to 0.20 +/- 0.14 and to 0.19 +/- 0.10, respectively (p < 0.01) during the third occlusion. The i.c. ECG ST elevation (normalized for the QRS amplitude) was not different between the two groups at the first occlusion (0.25 +/- 0.13 in the adenosine group, 0.25 +/- 0.19 in the control group). It decreased significantly during subsequent coronary occlusions to 0.20 +/- 0.15 and to 0.17 +/- 0.13, respectively. There was a correlation between the change in CFI (first to third occlusion; deltaCFI) and the respective ST elevation shift (deltaST): deltaST = -0.02 to 0.78 x deltaCFI; r = 0.54, p = 0.02. CONCLUSIONS: Even in patients with few coronary collaterals, the myocardial adaptation to repetitive ischemia is closely related to collateral recruitment. Pharmacologic preconditioning using a treatment with i.c. adenosine before angioplasty does not occur. The variable responses of ECG signs of ischemic adaptation to collateral channel opening suggest that ischemic preconditioning is a relevant factor in the development of ischemic tolerance.

Adenosine↗

PubMed1999

Coronary and peripheral artery remodeling in patients undergoing PTCA: An intracoronary and transcutaneous ultrasound study.

The aim of this study was to assess the relationship between the plaque burden of nonstenotic coronary artery segments and the wall thickness of peripheral arteries using intracoronary and transcutaneous ultrasound imaging, respectively. Intracoronary ultrasound (CVIS, 3.5 Fr) was performed in 27 patients undergoing percutaneous transluminal coronary angioplasty. Carotid arteries were imaged by B-mode ultrasound with semiautomatic edge detection and radial arteries by high resolution A-mode echotracking (NIUS 2). Quantitative measurements included coronary artery intima-media cross-sectional area (IM(CSA)) and cross-sectional narrowing (CSN), as well as intima-media thickness (IMT) and lumen radius (r) of the common carotid and the radial arteries. Intima-media thickness was increased in coronary, carotid, and radial arteries. Coronary arteries had an IM(CSA) of 7.7 +/- 2.5 mm(2) and a CSN of 24% +/- 8%. Despite this moderate plaque burden, lumen area was preserved (12.3 +/- 4.2 mm(2)) because of compensatory enlargement of coronary arteries. Right and left carotid and right radial arteries had an IMT of 575 +/- 78 microm, 570 +/- 129 microm, and 328 +/- 61 microm, respectively. There was no correlation between coronary IM(CSA) and carotid IMT (r = 0.07) or radial IMT (r = 0.02), and there was no correlation between coronary CSN and carotid IMT/r (r = 0.12), or radial IMT/r (r = 0.25). In conclusion, in these patients with symptomatic ischemic disease no relationship between IMT of the coronary arteries and IMT of carotid or radial arteries was found. Although increasingly popular, IMT of peripheral arteries may be of limited value as surrogate marker for the severity of coronary artery disease. Cathet. Cardiovasc. Intervent. 48:12-17, 1999.

Adult↗

PubMed1999

Simultaneous intracoronary velocity- and pressure-derived assessment of adenosine-induced collateral hemodynamics in patients with one- to two-vessel coronary artery disease.

OBJECTIVES: The purpose of this investigation in patients with poorly and well developed coronary collaterals was to assess the influence of collateral and collateral adjacent vascular resistances and, in part, a stenotic lesion of the collateral supplying vessel on the hemodynamic collateral responses to adenosine. BACKGROUND: In humans, little is known about the functional behavior of the coronary collateral circulation. METHODS: In 50 patients with one- and two-vessel coronary artery disease (CAD) undergoing percutaneous transluminal coronary angioplasty (PTCA), collateral flow index (CFI, no unit) changes and vascular resistance index (R, cm/mm Hg) changes of the collateral (R(coll)) and the distal collateral receiving (R4) vessel in response to adenosine (140 microg/min/kg IV) were measured by intracoronary (i.c.) Doppler and pressure guidewires. The variables were determined at baseline and during adenosine in patients with poor (angiographic collateral degree before PTCA <2 of 0 to 3) and good coronary collaterals. RESULTS: Pressure-derived CFI (CFI(p)) decreased under adenosine in patients with poor collaterals, and it increased in the group with good collaterals. There were inverse correlations between the adenosine-induced change in CFI(p) and the change in R(coll) (r = 0.61, p = 0.0001). In the group with good, but not with poor collaterals, there was also a significant correlation between CFI(p) increase and the decrease in R4, between the severity of the contralateral stenosis and CFI(p) augmentation and among the left versus right coronary artery as ipsilateral vessel and CFI(p) change. CONCLUSIONS: Overall, patients with well, versus poorly developed coronary collaterals do better regarding the capacity to increase collateral flow in response to adenosine. In patients with good, but not poor, collaterals, an adenosine-induced collateral flow increase depends on the ipsilateral distal vascular resistance decrease, but is also directly influenced by the severity of a contralateral stenosis and probably by the size of the collateralized vascular bed.

Adenosine↗