Search PubMed⌕ Search

Biomedical subjects

B Meier

Publications and source records attributed to B Meier.

At least 397 records · Page 22Linked to original sources
PubMed1987

[Percutaneous coronary angioplasty in unstable angina and acute infarction].

Unstable angina represents an indication for percutaneous transluminal coronary angioplasty (PTCA) provided it is based on a significant fixed lesion. A primary success rate of about 90% can be expected, but in 5% to 10% the intervention will cause a myocardial infarction. Mortality is higher than in patients with stable angina and does not differ from that of bypass surgery; however, it is still below 1%. At 1 year, 50% to 90% of the patients treated with initial success are asymptomatic if redilatations for recurrences (occurring in about one third) are included. - Acute myocardial infarction was introduced as an indication for PTCA in about 1980. PTCA was first used for failures, then for incomplete successes of intracoronary streptokinase therapy, and finally in patients without pretreatment. Currently, PTCA is being evaluated in multicenter studies as an adjunct to early intravenous fibrinolysis with clot specific agents (e.g., tissue-type plasminogen activator). PTCA achieves adequate initial reperfusion in about 80% irrespective of concomitant fibrinolytic therapy. It is complicated by occlusion of an already partially recanalized vessel in 4%. Late reocclusions occur in 15%, half of them accompanied by reinfarction. Intrahospital mortality is about 5% and increases by 1% up to 1 year. PTCA has its place in the treatment of unstable angina and acute infarction. In the latter it may be advantageous to precede it with early intravenous fibrinolysis.

Angina Pectoris↗
PubMed1987

Angiographic follow-up after multivessel percutaneous transluminal coronary angioplasty.

In 100 consecutive patients undergoing multivessel percutaneous transluminal coronary angioplasty (PTCA), dilation was attempted in 207 arteries. Primary success was achieved in 85 patients. Complications occurred in 8 patients: acute myocardial infarction in 5 and need for emergency coronary artery bypass surgery in 5. Control angiography was done in 77 of 85 patients (91%) with primary success at a mean of 12 +/- 6 months. Complete revascularization had been achieved in 59 patients and incomplete revascularization in 18. Angiographic restenosis was found in 39 of 77 patients (51%) and in 47 of 143 arteries (33%) at 9 +/- 7 months. The restenosis rate was 57% for chronic total occlusions (8 of 14) and 30% for stenoses (39 of 129). The restenosis rate was significantly higher for the left anterior descending coronary artery (40%) than for the left circumflex coronary artery (21%). However, the significance was lost after exclusion of chronic total occlusions. A higher residual stenosis and a high coronary wedge pressure were predictors for restenosis. Restenosis was clinically silent in 14 patients (18%). Repeat PTCA was done in 19 patients with recurrence and elective surgery in 8. Clinical follow-up was available in all patients at 24 +/- 12 months. Patients with incomplete revascularization had less favorable clinical follow-up results than patients with complete revascularization: 44% (8 of 18) vs 81% (48 of 59) were asymptomatic (p less than 0.005), and 28% (5 of 18) vs 5% (3 of 59) had undergone elective bypass surgery during follow-up (p less than 0.005). Most patients with restenosis after multivessel PTCA had only 1-vessel restenosis and only 7% had restenosis of all lesions.

Angiography↗
PubMed1987

[Change in indications for coronary angiography in a decade].

To characterize the changes in indications for coronary angiography we compared indications and therapeutic conclusions of cardiac catheterization, including coronary angiography, in 100 consecutive patients in 1975 and 100 consecutive patients in 1985. The baseline characteristics of the patients in the two groups were similar, except for age (50 +/- 10 vs 56 +/- 9 years, p less than 0.0001) and prior angioplasty (0 vs 12, p less than 0.0001). The main indications for coronary angiography in the two groups were (1975 vs 1985) chest pain in 67 vs 62 (n.s.), myocardial infarction in 10 vs 17 (n.s.), prior coronary surgery in 3 vs 0 (n.s.), major arrhythmias in 1 vs 1 (n.s.), and incidental (coronary pathology not the primary issue) in 19 vs 8 (p less than 0.05). We further analyzed each of the main indications in the two groups. Chest pain: angina ruled out in 21% vs 26% (n.s.), stable angina 64% vs 61% (n.s.), unstable angina 15% vs 13% (n.s.), positive non-invasive tests 39% vs 44% (n.s.). Myocardial infarction: acute intervention 0 vs 12% (n.s.), angina after infarction 20% vs 47% (n.s.), positive non-invasive tests after myocardial infarction 20% vs 41% (n.s.). Incidental: valvular heart disease 57% vs 63% (n.s.), cardiomyopathy 26% vs 13% (n.s.), congenital heart disease 11% vs 0 (n.s.), aortic dissection 5% vs 25% (n.s.), other 5% vs 0 (n.s.). Overall, clinical suspicion of coronary artery disease was confirmed and documented in 80% (65/81) vs 77% (61/79) of patients (n.s.), and normal coronary arteries were found in 20% (16/81) vs 23% (18/79) of patients respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Rapid and sensitive determination of dehydroascorbic acid in addition to ascorbic acid by reversed-phase high-performance liquid chromatography using a post-column reduction system.

An improved procedure for the direct determination of l-dehydroascorbic acid (DHAA), in addition to l-ascorbic acid (AA), has been developed. The two biologically active forms of vitamin C were separated using reversed-phase high-performance liquid chromatography. DHAA was reduced to AA with dithiothreitol (DTT) in a post-column reaction system. Complete conversion was achieved at 50 degrees C using a 1-ml reaction coil. Recoveries were in the range of 95-99% and both forms could be detected spectrophotometrically at 267 nm with high sensitivity. Reproducible results [relative standard deviations 2.4% (DHAA) and 1.0% (AA), n = 5] were obtained when the method was applied to the analysis of rose hip samples.

Ascorbic Acid↗
PubMed1987

Percutaneous transluminal coronary angioplasty for chronic total coronary arterial occlusion.

Experience is reported with 100 consecutive patients in whom percutaneous transluminal coronary angioplasty (PTCA) was attempted on chronically occluded coronary arteries that had no visible anterograde flow. Ninety-eight patients had angina and all had collateral vessels to the occluded artery on angiography. A movable guidewire/dilatation system was used in all cases. Overall initial PTCA success rate was 56% and was related to duration of occlusion (69% success rate for occlusions of 1 month or less, 50% for 1 to 6 months and 11% after 6 months). Complications were minor; no patient died or required emergency bypass operation. Of the 44 patients in whom PTCA failed, 20 underwent elective bypass surgery for relief of angina and 24 were treated medically. Follow-up at a mean of 8 months (range 1 to 48) was available for 49 of the 56 patients in whom PTCA was successful: 40 had subjective improvement, 6 no change and 3 felt worse. Control angiography was carried out in 40 of the 56 patients with primary success and showed long-term success in 18 and reocclusion or significant stenosis in 22. Of these 22, 11 were successfully treated by a second PTCA, 2 underwent operation and 9 were treated medically. Recanalization of totally occluded coronary arteries with no forward flow has a lower initial success rate (56%) than PTCA for stenoses and the recurrence rate is higher (55%), but effective relief of angina is achieved in successful cases. The risk of serious complications appears to be low.

Adult↗
PubMed1987

Percutaneous transluminal coronary angioplasty by high-volume and low-volume operators.

We retrospectively compared the results of percutaneous transluminal coronary angioplasty (PTCA) of three low-volume operators (1.3 PTCAs/month) to those of a relatively high-volume operator (14.9 PTCAs/month) in 396 consecutive procedures (358 patients). PTCA for multiple vessels, total occlusions, or evolving acute myocardial infarction had been excluded. For low-volume operators experienced assistance was considered present when the high-volume operator participated as second operator. The three low-volume operators performed 42, 38, and 24 PTCAs, respectively. Success rates per procedure for these operators were 88%, 84%, and 83%, and the complications rates 5%, 3%, and 13%, respectively. The success rates for assisted vs. nonassisted procedures were 89% vs. 88%, 100% vs. 78%, and 90% vs. 71%, and the complications rates were 6% vs. 4%, and 0% vs. 21%, respectively. The high-volume operator performed 292 PTCAs, with a success rate of 93%, and a complication rate of 5%. The cumulated success rate of the three low-volume operators of 85% was significantly (p less than 0.05) lower than the 93% success rate of the high-volume operator, while the complication rates of 6% and 5%, respectively, were not significantly different. Low-volume operators in an experienced center can perform PTCA safely even without assistance by a high-volume operator. However, their success rate is lower.

Angioplasty, Balloon↗
PubMed1987

Coronary angioplasty: results with expanded indications.

We reviewed 600 consecutive percutaneous transluminal coronary angioplasty procedures in 530 patients. There were 475 men (89%) and 55 women (11%) with a mean age of 55 +/- 9 years. Primary success per patient was 87%. Major acute complications occurred in 58 patients (10%): 2 deaths, vessel or side branch occlusion in 44 patients and ventricular fibrillation in 12 patients. Clinical follow-up was available in 344 of the first 348 patients (99%) at 12 +/- 6 months. Of these, 242 patients (70%) underwent control angiography at 12 +/- 6 months. Including repeat angioplasty, 82% of patients (281/344) with primary success were improved by at least one New York Heart Association functional class. Coronary events among the patients with no improvement were one sudden death, one myocardial infarction, and 16 bypass operations. Four subgroups of special interest were analysed: multivessel angioplasty (100 patients), angioplasty for chronic total occlusion (100 patients), angioplasty for evolving myocardial infarction (50 patients), and repeat coronary angioplasty (70 patients). Primary success rates were 87, 56, 84 and 90%, complication rates 9, 0, 9, and 3%, and recurrence rates 41, 48, 23, and 48%, respectively. At follow-up, improvement by at least one New York Heart Association class was observed in 77, 85, 88, and 80% of patients, respectively. Successful coronary angioplasty including repeat procedures achieved a long-term clinical success in about 80% of patients.

Angioplasty, Balloon↗
PubMed1987

Coronary wedge pressure: a predictor of restenosis after coronary balloon angioplasty.

Coronary wedge pressure is the pressure recorded distal to a stenosis while the inflated balloon occludes the coronary artery during angioplasty. This pressure has been shown to reflect actual (visible) and potential (recruitable) collateral flow to the stenosed artery, distal to the angioplasty site. In 100 consecutive vessels (91 patients) for which coronary wedge pressure had been measured at the time of angioplasty, the long-term (7 +/- 3 months) angiographic results was evaluated. The overall angiographic restenosis rate was 37%. It was 52% (25 of 48) in arteries with a coronary wedge pressure greater than or equal to 30 mm Hg and 23% (12 of 52) in arteries with a coronary wedge pressure less than 30 mm Hg (p less than 0.01). The mean coronary wedge pressure was 30 +/- 10 mm Hg for vessels with restenosis and 26 +/- 9 mm Hg for those without restenosis (p less than 0.01). The prevalence of angiographically visible collateral flow was 42% and 29%, respectively (p = NS). Neither age, sex, presence of unstable angina, left ventricular function, number of diseased vessels nor initial and final transstenotic pressure gradient and degree of stenosis were significantly associated with the long-term outcome after angioplasty. Restenosis rate is significantly increased when coronary wedge pressure measured at the time of angioplasty is high (greater than or equal to 30 mm Hg). This suggests a negative influence of competitive collateral flow on long-term results of angioplasty.

Angiography↗
PubMed1987

Improvement of left ventricular contraction and relaxation synchronism after recanalization of chronic total coronary occlusion by angioplasty.

Twenty patients with a chronic total coronary artery occlusion were studied before and 1 to 48 months (mean 9) after successful recanalization by angioplasty and compared with a group of 20 normal subjects. Before angioplasty, 19 of these 20 patients had angina. Collateral vessels to the distal part of the occluded vessel were visible in all 20 patients. A previous myocardial infarction was documented in 14 patients (9 with a Q wave and 5 with a non-Q wave infarction). At the time of follow-up, three patients were symptomatic: one had unstable angina and two had a positive stress test. The follow-up angiogram showed a significant restenosis in six patients and reocclusion in two. The mean ejection fraction had improved slightly from 59 +/- 11% to 63 +/- 9% (p less than 0.05). Left ventricular wall motion synchronism was studied using two variables for 128 shortening segments: the "time of peak contraction" and the "time of peak relaxation," as obtained from biharmonic Fourier transformation for each segment. Their respective standard deviations reflect the synchronism of contraction and relaxation. The mean standard deviations of the two variables expressed in degrees of one cardiac cycle (360 degrees) were respectively: 5.5 +/- 0.4 degrees for the time of peak contraction and 6.0 +/- 0.5 degrees for the time of peak relaxation in the 20 normal subjects, 11.7 +/- 1.7 degrees and 23.0 +/- 3.0 degrees before recanalization and 9.6 +/- 1.8 degrees and 12.5 +/- 2.2 degrees at follow-up in the group of 20 patients. These values were significantly higher (p less than 0.05) in the patients than in the normal group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Inadequate flow after internal mammary-coronary artery anastomoses.

The use of the internal mammary artery for revascularization of the coronary arteries has expanded over the last years. In a series of 250 consecutive coronary artery revascularizations, there was at least 1 internal mammary-coronary artery anastomosis in 222 patients (89%) and multiple internal mammary-coronary artery anastomoses were performed in 77 patients (31%). During the revascularization procedure, weaning from cardiopulmonary bypass was not possible in 4 patients with internal mammary-coronary artery anastomoses. These 4 patients showed signs of left ventricular failure, and additional saphenous vein bypass to the left anterior descending coronary artery, already revascularized by the left internal mammary artery, was performed. Weaning from cardiopulmonary bypass was then possible in 3 out of 4 patients. Thus, in some patients (1.2%), internal mammary-coronary artery anastomoses provide inadequate nutritional support for the myocardium.

Adult↗
PubMed1987

Digital videodensitometric measurement of aortic regurgitation.

A videodensitometric method for quantification of aortic regurgitation which requires neither measurement of cardiac output nor determination of enddiastolic and endsystolic left ventricular volumes has been developed. The injection of 20 ml of contrast medium into the left ventricle is digitally recorded at 25 images s-1 during 20 s using an equipment for digital subtraction angiography (Digitron 2, Siemens). The Digitron computes 2 'time dilution curves' (TDC) from the unsubtracted image sequence, for 2 regions of interest drawn around the angiographic enddiastolic and endsystolic left ventricular silhouettes. Enddiastolic and endsystolic points of the TDC are then entered into a VAX-750 computer, which calculates the ejection fraction (EF), the forward ejection fraction (FEF) and the regurgitant fraction (RGF). This is performed by a complex fitting algorithm based on a physical model of the washout process of contrast medium, which reconstructs the two best enddiastolic and endsystolic baselines in the washout parts of the two TDC. The EF, FEF and RGF obtained in 9 regurgitant and 11 nonregurgitant patients have been compared with the corresponding values EFv, FEFv and RGFv obtained by a conventional technique (Cardiogreen and biplane LV area-length volumetry). Regression analysis yielded: EF = 0.88 X EFv (regression line forced through the origin), r = 0.77, FEF = 0.76 X FEFv + 3, r = 0.96, RGF = 0.94 X RGFv + 5, r = 0.98 (v stands for volumetry).

Absorptiometry, Photon↗
PubMed1987

Flow reversal in coronary collaterals.

We report a case of collateral flow reversal observed seven months after angioplasty and due to the progression of a second lesion in another vessel. Such an occurrence has not been reported previously in association with angioplasty. Its clinical implications are discussed.

Adult↗
PubMed1987

Follow up results of treatment of unstable angina by coronary angioplasty.

Eighty nine of 327 consecutive patients undergoing coronary angioplasty at a centre had unstable angina--defined as either a worsening of the frequency or the severity of chest pain or severe episodes of chest pain at rest with no evidence of acute myocardial infarction. Multivessel disease was present in 31 of these patients. Two or more vessels were dilated in the same procedure in one fifth of the patients. Primary success was obtained in 80 (90%) patients. Acute myocardial infarction was a complication in four (5%) patients, including two of four patients who needed emergency coronary bypass grafting. Follow up coronary angiography at a mean (SD) of 10 (6) months in 57 patients showed restenosis in 21 (37%): of these, 13 patients had repeat coronary angioplasty and three had elective coronary bypass grafting. All patients in whom angioplasty was initially successful were followed up for 10 (6) months after the last angioplasty procedure. There were no deaths. One patient had sustained a myocardial infarction unrelated to the dilated vessel. Clinically, 74 patients improved by at least one New York Heart Association class and 40 (50%) were symptom free and with no signs or symptoms of myocardial ischaemia on a stress test. Coronary angioplasty offers long term symptomatic improvement at an acceptable risk in the majority of patients with unstable angina.

Adult↗