Quantification of aortic regurgitation with amplitude-weighted mean flow velocity from continuous wave Doppler spectra.

Aortic regurgitant fraction (RFao) was quantified by estimating the ratio of the forward blood flow through the aortic (Qao) and pulmonary (Qp) valve: RFao = 100(Qao - Qp)/Qao. Aortic and pulmonary flow were measured by the systolic time integrals of the amplitude-weighted mean velocity from continuous wave Doppler spectra recorded over the aortic and pulmonary valves. Thus, measurements are independent of the left and right ventricular outflow tract area. In 20 normal subjects, aortic regurgitant fraction ranged between -2.9% and +12.0% (mean +4.3%), the physiologic value being +2%. In 20 patients with pure aortic regurgitation, aortic regurgitant fraction obtained by Doppler spectra (y) was compared with that calculated from biplane left ventriculography and cardiac output determined with the Fick method (x). The correlation was r = 0.94, (SEE = 5.4%, which is 10.6% of the angiography-Fick mean value). The regression line was y = 0.87x + 6.6 (mean y = 51.2%, mean x = 51.1%). It is concluded that determination of aortic regurgitant fraction in pure aortic regurgitation by using the amplitude-weighted mean velocity from continuous wave Doppler spectra is accurate and allows easy noninvasive evaluation of the regurgitant fraction in routine clinical applications.

Cutaneous and coronary flow reserve in patients with microvascular angina.

Microvascular angina is characterized by exercise-induced angina in patients with normal coronary arteries and reduced coronary flow reserve. Recently, a generalized disorder of abnormal vascular reactivity in microvascular angina has been postulated. Therefore, coronary flow reserve was determined by the coronary sinus thermodilution technique and compared with the cutaneous flux ratio in 6 control subjects (group 1) and 12 patients with microvascular angina (group 2). Coronary flow reserve was calculated from maximal coronary flow after 0.5 mg/kg of dipyridamole divided by flow at rest. Cutaneous flow ratio was estimated by laser Doppler fluxmetry (right forearm) before and after 4 min of suprasystolic blood pressure occlusion. Coronary flow at rest was identical in the two groups, but after maximal vasodilation with dipyridamole, coronary flow was higher in group 1 than in group 2 (p less than 0.05). Coronary flow reserve differed significantly between the two groups (2.9 in group 1 and 1.3 in group 2; p less than 0.001). Cutaneous Doppler flux at rest was higher in group 1 than in group 2 (p less than 0.05). However, the hyperemic response was identical in both groups. It is concluded that the cutaneous flux ratio in patients with microvascular angina is not impaired. Local peripheral vasomotor tone appears to be increased in patients with microvascular angina because cutaneous flow at rest is reduced. Thus, a generalized disorder of abnormal vascular reactivity cannot be confirmed in patients with microvascular angina.

Right ventricular diastolic function during exercise: effect of ischemia.

The effects of exercise on right ventricular diastolic function were evaluated in 14 patients who underwent supine rest and exercise right ventricular angiography. On the basis of coronary anatomy and exercise left ventricular regional wall motion analysis, these patients were classified into two groups: Group 1 (n = 7) had no or only mild coronary artery disease and Group 2 (n = 7) had significant coronary disease and exercise-induced left ventricular wall motion abnormalities suggesting ischemia. Chamber stiffness at rest was higher in Group 2 (48 x 10(-3) ml-1/m2) than in Group 1 (18 x 10(-3) ml-1/m2, p = 0.006). During exercise, right ventricular filling rate in the second half of diastole was significantly lower in Group 2 (126 versus 276 ml/m2 per s, p less than 0.03). The time constant of right ventricular pressure decay decreased significantly in both groups with exercise; however, both groups displayed a parallel upward shift of the pressure-volume curve with exercise. Because ischemia could not be demonstrated in Group 1, it is an unlikely explanation for this shift. Septal shifting was not a significant factor with exercise. Because of an increase in left ventricular end-diastolic volume with exercise and a close correlation between right and left ventricular end-diastolic pressures (r = 0.96 for Group 1 and r = 0.76 for Group 2), pericardial constraint is the most likely cause for this upward shift of the pressure-volume curve. Therefore, an increase in right ventricular end-diastolic pressure may not be a reliable indicator of ischemia during exercise because this pressure is coupled to changes in left ventricular volume and pericardial constraint.

[Normal values of left ventricular function. Biplanar angiocardiography with reference to sex-specific differences]. / Normalwerte der linksventrikulären Funktion. Biplane Angiokardiographie, unter Berücksichtigung geschlechtsspezifischer Unterschiede.

Normal values of left ventricular function have been determined in 24 patients by means of biplane angiocardiography. Global parameters were chamber volume, ejection fraction and muscle mass. Regional ventricular function was determined by means of an orthogonal and radial axial system. Radial axis shortening parameters showed smaller standard deviations and smaller coefficient of variations than orthogonal parameters. The smallest coefficient of variation elicited regional area reduction methods. Women showed significantly lower chamber volumes and muscle mass than men. There was no difference between the two sexes in the ejection fraction and wall thickness.

Silent myocardial ischemia. How to diagnose? How to treat?

1. The diagnosis of silent ischemia in asymptomatic patients with known coronary artery disease is adequately achieved by stress testing. 24 hour monitoring allows to assess the total ischemic burden which has prognostic implications. 2. The diagnosis of silent ischemia in asymptomatic patients without documented coronary artery disease is difficult. Stress testing should be carried out in selected patients with multiple risk factors. No mass screening by stress tests can be recommended because of the many false positive results and exorbitant costs. 3. Ischemia regardless whether painful or painless is an independent prognostic factor. 4. Drug treatment reduces or abolishes total ischemic burden. Its impact on prognosis is yet unknown but ongoing multicenter studies (TIBET, TIAP) might clarify the issue. 5. Successful PTCA can abolish silent ischemia. 6. In patients with silent ischemia, as in symptomatic patients, survival is better with surgical than with medical treatment in the presence of 3-vessel disease or reduced left ventricular function.

[Is regression of coronary sclerosis possible?]. / Ist eine Regression der Koronarsklerose möglich?

Randomized studies with sequential coronary arteriographies have clearly documented that aggressive lipid-lowering therapy and change in life style can reduce progression and produce a modest regression of coronary artery lesions. The changes in the extent of a stenosis are determined by the level of cholesterol and LDL cholesterol achieved during treatment. Three of the randomized studies have shown that the lipid-lowering intervention has not only a beneficial influence on the coronary arteriographic lesions, but the number of clinical events is reduced as well. The calcium blockers nifedipine and nicardipine do not influence progression and regression but reduce the de novo appearance of coronary stenoses, either expressed as number of lesions per patient or as percentage of patients with new stenoses.

[Digital subtraction angiography for the assessment of myocardial perfusion]. / Digitale Subtraktionsangiographie zur Bestimmung der Myokardperfusion.

Coronary angiography does not only permit to evaluate the severity of coronary disease but also to assess coronary flow reserve in various myocardial perfusion areas by digital processing. Use of colour flow mapping allows the assessment of both, density as well as distribution velocity of contrast-medium (= parametric imaging). The advantage of this technique is given by the possibility to assess coronary flow reserve not only at rest but also under physiologic situations such as bicycle ergometry. Clinical investigations have shown that coronary flow reserve determined after papaverine administration does not correlate with physiologic conditions such as physical exercise.

[Prinzmetal's variant angina: a case report]. / Variante Prinzmetal-Angina pectoris: ein Fallbericht.

Prinzmetal's angina is a variant of the classic exertion dependent angina pectoris. Typical is the appearance of the symptoms at rest during early morning hours. It is due to spasms in the coronary arteries. Various provocation tests may be used to trigger spasms, among others hyperventilation which leads to vasoconstriction of coronary arteries. The case of a 53-year-old patient with Prinzmetal's angina is described in whom spasms of the right coronary artery could be evoked by hyperventilation. The following pathogenetic mechanisms may be possible in Prinzmetal's angina: disturbed endothelial permeability, endothelial dysfunction, or secretion of vasoconstrictive substances as well as local hypersensitivity of segments disturbed by atherosclerotic lesions to circulating vasoconstrictors.