Biomedical subjects

K K Haase

Publications and source records attributed to K K Haase.

78 records · Page 5Linked to original sources

PubMed1990

[Percutaneous coronary Excimer laser angioplasty in patients with coronary heart disease].

To verify the efficacy and safety of percutaneous coronary excimer laser angioplasty in patients with coronary artery disease a prospective study was conducted in 60 patients. The application of laser light was possible in 55 of the 60 patients. A novel 1.4-mm diameter catheter with 20 quartz fibers of 100-microns diameter, each arranged concentrically around a central lumen suitable for an 0.014-inch flexible guide wire was used. The light source was a commercial excimer laser emitting energy at a wavelength of 308 nm, with a pulse duration of 60 ns. The laser was operated at 20 Hz; mean energy transmission was 30 +/- 5 mJ/mm2. In 23 of the 55 patients treated with excimer laser energy the qualitative angiographic results were sufficient. In 32 patients additional balloon angioplasty was necessary, either because of an insufficient result or due to vessel closure after laser ablation. In 47 of the 55 patients control angiography was performed within the 6-month follow-up period. Rate of restenosis was higher in patients treated with laser ablation and subsequent balloon angioplasty (16 of 28) than in patients treated with laser ablation alone (6 of 19). Results of the 6-month observation period suggest that 1) coronary excimer laser angioplasty in combination with subsequent balloon angioplasty results in a considerable increase of the restenosis rate; 2) the exclusive use of laser ablation also results in a restenosis rate comparable to balloon angioplasty alone; and 3) the impact of this new method using improved application systems and higher energy transmission has to be determined in further studies.

Angina Pectoris↗

PubMed1989

Initial angiographic results in ablation of atherosclerotic plaque by percutaneous coronary excimer laser angioplasty without subsequent balloon dilatation.

Percutaneous transluminal coronary excimer laser angioplasty was performed in 15 patients using a 1.3-mm diameter laser catheter. The catheter consists of 20 concentric quartz fibers of 100 microns diameter each located around a central lumen suitable for a 0.014-inch flexible guidewire. The catheter was coupled to an excimer laser delivering energy at a wavelength of 308 nm and at a pulsewidth of 60 ns. Quantitative analysis of the angiograms documented a decrease from 77 +/- 15% diameter stenosis before intervention to 40 +/- 22% after the first irradiation cycle and to 21 +/- 17% after termination of laser ablation. The minimal lumen diameter increased from 0.4 +/- 0.2 to 1.3 +/- 0.4 and to 1.6 +/- 0.4 mm, respectively. Vessel reocclusion was seen in 2 patients at 24-hour control angiography. No procedure-related major complications such as vessel perforation occurred. In 8 patients, however, intraluminal lucencies were seen, which were persistently visualized 24 hours after intervention in 6 patients. Despite pretreatment with intracoronary nitroglycerin, coronary spasm occurred in 8 patients and was reversible after additional sublingual vasodilator therapy. The results of this pilot study suggest that percutaneous coronary excimer laser angioplasty is feasible and effective for ablation of coronary lesions in selected patients and can be performed without subsequent conventional balloon angioplasty. The clinical impact of this new interventional technique, however, remains to be assessed.

Angiography↗

PubMed1989

Percutaneous coronary excimer laser angioplasty: initial clinical results.

A novel 1.3 mm diameter laser catheter, consisting of 20 concentric 100 microns quartz fibres around a central lumen for a 0.35 mm flexible guide wire, was used to ablate atherosclerotic tissue in thirty patients with coronary artery disease. The laser catheter was coupled to an excimer laser delivering energy at a wavelength of 308 nm and a pulsewidth of 60 ns. The primary success rate was 90% (27 of 30 lesions). The mean (SD) percentage stenosis fell from 85 (15)% to 41 (19)% after laser ablation. In ten patients the lumen diameter after laser angioplasty was considered sufficient, but subsequent balloon angioplasty was carried out for the other twenty patients. Failure to pass the lesion was caused by vessel kinking in two patients and a total occlusion in one patient. No complications directly attributable to laser ablation, such as vessel wall perforation, occurred; one dissection occurred but had no clinical sequelae. There was one early reocclusion and death in a patient with triple vessel disease and unstable angina, probably as a result of plaque rupture after balloon angioplasty. These results are encouraging and justify further clinical investigations.

Angioplasty, Balloon↗

PubMed1989

[Percutaneous transluminal excimer laser coronary angioplasty].

Percutaneous transluminal laser coronary angioplasty (PTLCA) was undertaken in five patients (four men and one woman, aged 44-72 years) with coronary artery stenosis. The vessel diameter was increased in all patients after PTLCA; complete ablation of the atheromatous plaque succeeded in three. In the other two the catheter could not be advanced across the entire stenotic region. After PTLCA the stenoses were 40-50% of normal lumen. Balloon dilatation was additionally done in all five patients. In three this caused dissection of the vessel wall distal to the stenosis and possible intracoronary thrombus formation: this would suggest that balloon dilatation after laser angioplasty is not recommendable. PTLCA widens the spectrum of invasive methods for treating coronary artery stenosis.

Adult↗

PubMed1989

[Success and complication rates of coronary angioplasty in the unstable angina pectoris stage after myocardial infarct--a comparison with percutaneous transluminal coronary angioplasty in the acute infarct stage and unstable angina pectoris without preceding myocardial infarct].

To evaluate whether there is a difference in terms of the success and complication rates of PTCA in patients (pts) with unstable angina pectoris (UAP) after myocardial infarction (group I) and patients with myocardial infarction (group II), as well as in patients with UAP without preceding myocardial infarction (group III), we analyzed the data of 188 patients retrospectively. Acute PTCA was performed in 42 patients of group I, 55 patients of group II, and 91 patients of group III. The primary success rate was comparable in all three groups (group I: 74%; group II: 76%; group III: 77%). The incidence of acute ACVB operation was comparable in group I (5 pts: 9%) and group III (10 pts: 11%). One patient was operated during an acute myocardial infarction. Five patients of group I (9%) and seven patients of group III (8%) developed a myocardial infarction. Three patients of group I (7%) and three patients of group II (5%) died during hospitalization. PTCA performed during acute myocardial ischemia has the highest complication rate in patients with UAP after myocardial infarction and is considerably higher than in patients with UAP without preceding infarction.

Angina Pectoris↗

PubMed1989

[Effect of laser irradiation on atherosclerosis vascular segments in relation to wave length and pulse width].

The interaction of pulsed Nd:YAG laser radiation and atherosclerotic vessel wall is reported. The effects in the area of radiation were examined at an infrared, green, and ultraviolet wavelength at variable pulsewidths. The laser beam was focused directly on the plane surface of the tissue. The macroscopic and histologic examinations demonstrate that thermal damage of tissue is higher at an infrared wavelength than at a green wavelength and respectively at an ultraviolet wavelength. With increasing pulsewidth an increase of coagulation and necrosis of plaque material and adjacent vessel wall can be noted. The results show that for the precise ablation of plaque without adjacent vessel wall injury short pulsed ultraviolet radiation is preferable.

Angioplasty, Balloon, Coronary↗