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P Spiller

Publications and source records attributed to P Spiller.

12 recordsLinked to original sources
PubMed1979

Flow measurements and simultaneously performed angiography of aorto-coronary bypass grafts during bypass surgery.

The function of aorto-coronary bypass grafts is usually assessed by the run-off, determined from postoperatively performed cineangiograms. The reliability of this method was tested by comparing the electromagnetically measured graft flow with the run-off, qualitatively estimated from cineangiograms. The electromagnetic flow measurements and cineangiography were performed simultaneously during bypass surgery. The run-off was classified by three independent observers into three classes (poor, moderate, and good). The average mean flow rates corresponding to the three classes were: poor: Q = (43 +/- 11)ml/min; moderate: Q = (48 +/- 14)ml/min; good; Q = (63 +/- 22)ml/min. Although the differences between the flow rates of the three classes were found significant (except between poor and moderate run-off), there was a wide range of overlapping. Especially in grafts with low flow rates (Q less than 70 ml/min) there were pronounced disagreements between the qualitative estimation of flow and the electromagnetically measured flow. Using videodensitometric flow measurements as a check test, the uncertainties in classification proved to be caused by the lack of reliability of the observer. The flow rates in aorto-coronary bypass grafts can be determined reliably only by means of quantitative methods, e.g., electromagnetic or videodensitometric flow measurements.

Angiography↗
PubMed1979

[Ventricular and myocardial function in mitral regurgitation (author's transl)].

Left ventricular and myocardial performance were analyzed in 9 patients with chronic volume overload by mitral regurgitation from biplane cineventriculograms, simultaneous pressure recordings and cardiac output (thermodilution method) determinations. In spite of a considerable regurgitant fraction (49 +/- 17% of total stroke volume) cardiac index on the average is normal (CI = 3.3 +/- 0.7 l . min-1). The main compensatory mechanism to maintain cardiac ouput in hypertorphy (WED = 1.1 +/- 0.2 cm; LVMI = 216 +/- 62 g . m-2; LVMI/EDVI = 1.3 +/- 0.3 g . ml-1) and dilatation (EDVI = 163 +/- 37 ml . m-2). An increase of preload is of minor importance (PLVED = 15 +/- 7 mmHg; sigma ED = (40 +/- 19) x 10(3) dyn . cm-2). Left ventricular enlargement and wall mass are related to the degree of clinical heart failure (NYHA). Enddiastolic volume on the average is more increased than total stroke volume (89 +/- 31 ml . m-2). Ejection fraction (EF = 54 +/- 7%) was depressed despite a normal afterload (sigma tej = (171 +/- 37 x 10(3) dyn. cm-2; sigma max = (247 +/- 48 x 10(3) dyn . cm-2). The reduced ejection fraction and diminished myocardial power are related to an impairment of myocardial function (VMW . sigma tej = (83 +/- 39) x 10(3) dyn . cm-2 . s-1; VMW . sigma tej/ln sigma ED = 7.9 +/- 3.6 x 10(3) dyn . cm-2 . s-1). In comparable degrees of heart failure myocardial function is more compromised in patients with mitral than with aortic regurgitation.

Adult↗
PubMed1979

[Ventricular and myocardial function in aortic regurgitation (author's transl)].

The influence of chronic volume load on ventricular function and myocardial load and shortening was investigated in 10 patients with chronic aortic regurgitation by means of biplane ventriculography and simultaneous pressure measurements. The regurgitant fraction was 63 +/- 15 per cent. Enddiastolic volume (EDVI 227 +/- 37 ml/m2), systolic (161 +/- 18 mm Hg) and enddiastolic ventricular pressure (30 +/- 12 mm Hg) were elevated, ejection fraction was reduced (54 +/- 7 per cent). Myocardial mass related to EDV was normal (1.2 +/- 0.2 g/ml). Contractility as measured from dp/dt max (1736 +/- 492 mm Hg s-1) and dp/dtmax/PI (22.2 +/- 4.3 s-1) was slightly reduced. Mean velocity of equatorial midwall fiber shortening VMW 0.45 +/- 0.13 cir X s-1) was significantly diminished, equatorial midwall fiber stress during ejection (sigma tej 267 +/- 44.5 X 10(3) dyn X cm-2) was elevated. In spite of a very high enddiastolic stress (sigma ED 96 +/- 36 X 10(3) dyn X cm-2) mean systolic power (sigma tej X VMX 123 +/- 43.2 X 10(3) dyn X cm-2 X s-1) was normal. Compensation of chronic volume load in aortic regurgitation is not compensated by an increased contractility but by ventricular enlargement and a pronouned increase in preload. Myocardial load and shortening in chronic aortic regurgitation are altered in the same way (increased stress and reduced shortening) as in chronic pressure overload.

Adult↗
PubMed1978

[Results of endarterectomy in coronary artery surgery (author's transl)].

In a series of 432 aortocoronary bypass procedures endarterectomies were performed in 58 patients (13.4%) on 60 coronary arteries. Except of two vein patch grafts all endarterectomized arteries were bypassed with a saphenous vein graft. The majority of the patients had an endarterectomy of the right coronary artery. Clinical control investigations were performed in 43 out of 47 survivors including 30 with coronary angiograms 5.2 months (mean) after surgery. 26 out of 31 endarterectomized arteries (83.9%) were open angiographically whereas the patency rate to non-endarterectomized arteries of the same patients was 86.4%. The hospital mortality was high; 11 out of 58 patients (19%) deceased. All patients who died postoperatively had a three vessel disease with diffuse coronary sclerosis. Only three had no myodardial infarction prior to surgery, seven had one to four infarctions before surgery. The relatively high mortality intends for the future a more strict revision of the indications for coronary surgical procedures. But not in all cases the preoperative coronary angiograms and ventriculograms allow a clear estimation of the local arterial conditions.

Coronary Artery Bypass↗
PubMed1975

[Estimation of ventricular volume derived from three transverse diameters and the longitudinal axis, compared with an area-longitudinal axis method (author's transl)].

The difficulty of automatic volume estimations of the left ventricle from cine-ventriculography lies in the accurate definition of the ventricular contour during the whole of the cardiac cycle. On the other hand, automatic determination of the long axis of the ventricle, and of three transverse diameters, is feasible. An attempt was therefore made to see whether accurate ventricular volume estimations could be obtained from these measurements. Two different geometrical models were examined: a) A complete rotational ellipsoid b) A half rotational ellipsoid. Examination of ten cine-ventriculograms (totalling 546 frames) has shown that the ventricular volume can be determined with an adequate accuracy by this method. The half ellipsoid model produced better mean results than the full ellipsoid. Its mean deviation from the area-long axis method was only minus 1.2%, that of the complete ellipsoid was minus 3.3%.

Heart Function Tests↗
PubMedDate not supplied

Measurement of flow velocity in the model circulation by videodensitometry. Methodological investigations.

The relation between videodensitometrically measured front velocity and electromagnetically assessed flow was examined in a circulatory model with continuous as well as pulsatile flow (89 experiments). The diameter of the tubes in the videodensitometric measuring section was 0.305 to 0.518 cm. A linear correlation was proved in flow velocities up to Reynold's number Re = 225. The exact flow, measured electromagnetically, was overestimated in continuous flow by 21% (r = 0.99, Syx = +/- 14.5 ml/min) and in pulsatile flow by 24% (r = 0.98, Syx = +/- 20.8 ml/min). In view of these results the phasic and average flow can be calculated accurately using videodensitometric techniques.

Blood Flow Velocity↗