Biomedical subjects

H U Sauer

Publications and source records attributed to H U Sauer.

5 recordsLinked to original sources

PubMed1999

[Long-term outcome of therapy of recurrent myocardial ischemia after surgical revascularization].

UNLABELLED: Although there are randomized data for CABG vs. medical therapy and CABG vs. PTCA in primary therapy of CAD, there is few evidence on the appropriate therapy of recurrent angina after prior CABG. We analyzed data from 1265 consecutive patients (pts.) presenting for recurrent angina after previous CABG who required either re-CABG (n = 67), PTCA (n = 768) or medical therapy alone (medRx) (n = 430) at our institution during 1986 through 1996. Outcome after index therapy is monitored during 45 +/- 34 months. The 3 therapeutic groups were similar with respect to gender (84% male), age at therapy (60 years), prevalence of diabetes (22%), and time to first ischemic event after primary CABG (37 months). Actuarial survival was significantly higher in the PTCA-group at 1, 5 and 10 years after therapy of recurrent angina, despite the freedom from subsequent re-intervention was significantly lower (1-year-survival 95% [37%] vs. 95% [3%] medRx vs. 79% [4%] re-CABG, 5-year-survival 87% [57%] vs. 78% [17%] medRx vs. 50% [4%] re-CABG and 10-year-survival 72% [65%] vs. 63% [31%] medRx vs. 50% [15%] re-CABG resp., p < 0.0001, [numbers in brackets represent corresponding values for incidence of re-intervention, p < 0.0001]). These findings were similar after adjustment for different baseline characteristics. Following this adjustment multivariate Cox-analysis identified age beyond 70 years, diabetes mellitus and therapy: redo-CABG as independent correlates for mortality for the entire group. THERAPY: angioplasty was identified as an independent correlate for survival. In contrast, therapy: angioplasty was an independent correlate for re-intervention after therapy. CONCLUSIONS: In this nonrandomized series of patients with recurrent angina after previous CABG, an initial strategy of angioplasty resulted in a significant higher overall survival, although this regimen is associated with a greater need for subsequent revascularization procedures.

Adult↗

PubMed1995

Changes of fluid-dynamic parameters in peripheral stenoses with transcutaneous interventions.

UNLABELLED: Peripheral vessels provide a useful in vivo haemodynamic model allowing evaluation of local intravascular fluid dynamics. Velocity measurements using a 0.018 inch Doppler-tipped angioplasty guidewire, quantitative angiography and laboratory data were gathered from 45 patients with a total of 48 percutaneous transluminal laser assisted angioplasties (PTLA) in the superficial femoral, in the iliac, in the popliteal artery and in the peroneal artery. From these data, blood flow, whole blood viscosity, Reynold's numbers, Womersley numbers and shear stress were calculated, evaluated as to their changes post PTLA and correlated with clinical improvement at early follow-up. The clinical result was quantified as categorial improvement according to the American Heart Association guidelines. The primary angiographic results of angioplasty were satisfactory in all patients. Clinically 17/45 patients showed a marked, 6/45 a moderate, 18/45 a minimal, and 4/45 no improvement. The mean values of maximal peak velocity at stenosis decreased from 235 +/- 28 cms-1 to 84 +/- 8 cms-1 after PTLA (P < 0.01). The minimal intrastenotic cross section increased from 7.7 +/- 0.9 to 21.9 +/- 1.6 mm2 (P < 0.01). Mean trans-stenotic flow increased after intervention by about 50% (P < 0.01) and improved further by 135% after administration of adenosine triphosphosphate i.a. (P < 0.01). Reynold's numbers were elevated intrastenotically (1285 +/- 198) pre-intervention as compared to values proximal (564 +/- 81) and distal (449 +/- 66) to the stenosis and were reduced significantly (P < 0.05) at stenosis by PTLA, whereas values proximally and distally increased significantly (P < 0.01) post PTLA (proximal 829 +/- 84, intra 773 +/- 107, distal 676 +/- 98). Shear stress, reflecting mechanical interaction between flow and vessel wall, was elevated at stenosis pre-intervention to 44 +/- 8.9 Pa and reduced at post-stenoric vessel sites to 2.4 +/- 0.5 Pa. PTLA caused a decrease in stenosis to 6.3 +/- 1 Pa (P < 0.01) and an increase distally to 4.6 +/- 1 Pa (P < 0.01). Whereas in single stenoses removal of the obstruction was associated with a significant (P < 0.05) increase in trans-stenotic flow and shear stress distally, there was only auenuated increase in trans-stenotic flow in multiple lesions despite an angiographically good PTLA result. Shear stress distally remained low in those patients. Velocities and Reynold's numbers were lower in these vessels even pre PTLA. Residual flow, Reynold's number and minimal cross-section pre-intervention correlated significantly with clinical outcome. Pooling cases with no or minimal, as opposed to those with marked or moderate improvement, 81% of patients were correctly classified using the Reynold's numbers pre- and post-PTLA. CONCLUSION: Peak velocity monitoring is feasible and safe during angioplasty. Velocity provides clinically relevant physiological information in addition to angiography. Combining quantitative angiography, velocity measurements and laboratory data allow the calculation of blood flow, Reynold's numbers and shear stress, thereby providing complex fluid dynamic information. Thus the evaluation of haemo-dynamics in single and multiple obstructions before and after intervention is improved. Fluid dynamic parameters pre-and post-PTLA are significantly correlated with clinical short-term result.

Adult↗

PubMed1993

[Diagnosis of the dynamic lesion].

Rupture of atheromatous plaques, thrombosis and spastic contractions cause dynamic lesions in coronary arteries. This review focuses on the diagnostic approach to vasospastic lesions. Our current knowledge considers vasospastic angina as a--most likely--localized disease of the vascular smooth muscle, which occurs in nonatherosclerotic as well as in atherosclerotic segments. Currently the diagnosis can only be proven by functional tests under angiographical control. Since the pathophysiological mechanisms leading to vasospasm remain unclear, only empirically developed pharmacological tests are available. The use of ergonovine alkaloids is well established, the feasibility of acetylcholine is under investigation. The reproducibility regarding the course of the disease and the localization of the lesion has not yet been determined. The necessity to state the diagnosis is given by the improved prognosis of the disease under effective therapy with calcium channel blockers and nitrates.

Acetylcholine↗

PubMed1991

[Coronary fistulas--high prevalence in patients with heart transplantation].

Coronary artery fistulas have recently been reported to occur frequently in patients after heart transplantation due to repeated endomyocardial biopsies. To investigate if there is a relationship between development of coronary artery fistulas and the number of biopsies performed in transplanted patients, we studied the prevalence and localization of coronary artery fistulas in 168 patients after heart transplantation and in 100 control subjects. In addition to biplane ventriculography of the left ventricle, and in two-thirds of the patients the right ventricle as well, coronary angiography in multiple projections was performed at yearly intervals. The angiographic criterion for a coronary fistula was specified as visualization of a direct confluence from the arterial vascular lumen into a cardiac chamber, independent of size, which occurred prior to the venous phase, documented by opacification of the coronary sinus or great cardiac vein. The size of the fistula was assessed semi-quantitatively into one of three categories as small, barely detectable flow from a small arterial vessel with opacification of less than 10% of the involved chamber, large with direct flow from a large branch with opacification of more than one-third of the involved chamber (Figures 1a to 1c). Endomyocardial biopsies were performed weekly for the first three months after transplantation, thereafter, the interval was increased one week every three months. The prevalence of coronary fistulas in patients after heart transplantation was higher at 135/168 than in control subjects at 43/100. There were also more fistulas per patient (1.8 vs 0.67) in those transplanted than in control subjects (Figures 2a and 2b).(ABSTRACT TRUNCATED AT 250 WORDS)

Arteriovenous Fistula↗

PubMed1990

[Directional atherectomy--current status].

To deal with the problem of restenosis after PTCA, several new methods and devices for treating atheromatous lesions have been developed. Among the promising techniques, is the opportunity to remove atheromatous material with the directional coronary atherectomy catheter designed by J.B. Simpson. The atherectomy catheter consists of a housing at the catheter tip with a concave cutting device which is rotated at a speed of 2000 r.p.m. The housing is positioned at the stenosis by means of a central guidewire; the material to be removed protrudes into the housing. With an inflatable balloon on the opposite side, the position of the housing is fixed in the coronary artery, the plaque is pressed further into the orifice and severed by the rotating blade. The material removed remains in the tip of the housing and can be used for morphologic examination as well as for functional studies with individual cell cultures. Experience published to date encompasses the results of 1032 treated stenoses. The majority of the treated lesions, 53%, were localized in the left anterior descending coronary artery; in 22% the lesion were located in the right coronary artery, in 17% in an aorto-coronary venous bypass graft. Due to the difficulty in positioning the relatively rigid atherectomy catheter, the method has only been employed in the circumflex artery in 6%. In a substantial number of patients, the stenoses had already been subjected to PTCA; in 57% of 963 patients treated with atherectomy, angioplasty had been performed previously, in 25% bypass grafting had been carried out. The primary success rate was 93%.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗