Wolfram Burger

Late (Five to Nine Years) Follow-Up After Balloon Dilation of Valvular Pulmonary Stenosis in Adults

The transvalvular gradient was investigated in 14 patients with pulmonary stenosis 5 to 9 years after balloon valvuloplasty. None of the patients had developed restenosis, and in those who had a peak gradient >100 mm Hg before valvuloplasty, the gradient decreased further due to resolution of subvalvular muscular hypertrophy within 3 months after intervention.

Right ventricular function before and after percutaneous balloon mitral valvuloplasty

Aim of this study was to evaluate right ventricular performance in patients with mitral stenosis and its modification by balloon valvuloplasty. Right ventricular volumes of 24 patients with postrheumatic mitral stenosis were determined by thermodilution 1 or 2 days before and 1 or 2 days after valvuloplasty. Right ventricular ejection fraction at rest was 43 (36-47)% (median and interquartile range). Right ventricular end-diastolic volume was 100 (86-119) ml/m2. Supine bicycle exercise (50 Watt) reduced right ventricular ejection fraction to 30 (29-37)% (P < 0.0001) and increased right ventricular end-diastolic volume to 124 (112-141) ml/m2 (P < 0.0001). At rest, right ventricular ejection fraction correlated inversely with pulmonary vascular resistance (r = -0.64, P < 0.0001), while no significant correlation with mitral valve area was found. Valvuloplasty increased right ventricular ejection fraction at rest to 48 (44-50)% (P < 0.005), and during exercise to 42 (38-45)% (P < 0.0001). This improvement of right ventricular ejection fraction correlated inversely with the value of this parameter before valvuloplasty (r = -0.88, P < 0.0001) and with the gain in stroke volume (r = 0.57, P < 0.01). The right ventricular function curve, disturbed before commissurotomy, was reestablished by the procedure. In conclusion, at the here investigated stage of mitral stenosis right ventricular function is reversibly impaired. This is predominantly caused by the hemodynamic consequences of the valvular defect and not by an impairment of right ventricular myocardial function.

Effect of balloon valvuloplasty for mitral stenosis on right ventricular function.

Abstract Percutaneous balloon mitral valvuloplasty has become a common procedure in the treatment of pliable mitral stenosis. By this method, mitral valve area can usually be doubled, thus leading to significant hemodynamic and clinical improvements. 1,2 However, because evaluation of right ventricular volumes by contrast angiography or radionuclide methods is quite cumbersome and requires greater technical efforts, only few data exist on the effects of this procedure on right ventricular performance. 3 Recently, the evaluation of right ventricular function was made easier by the introduction of a computerized thermodilution catheter, thereby enabling bedside determination of right ventricular volumes and ejection fraction. 4,5 This method showed good correlation with contrast angiography and radionuclide methods. 4,5 Aim of the following study was the investigation of balloon mitral valvuloplasty on right ventricular function at rest and during exercise.

Effect of atenolol and celiprolol on acetylcholine-induced coronary vasomotion in coronary artery disease ☆

Earlier studies have reported on the potentiated muscarinic vasoconstriction of intracoronary acetylcholine after metoprolol application in patients with coronary artery disease. The present study investigated the effect of celiprolol, atenolol, and placebo on acetylcholine-induced vasomotion in patients with coronary artery disease. Furthermore, direct effects on coronary vasomotion and on hemodynamics were evaluated. Acetylcholine (intracoronary concentrations of 6.3x10(-7), 2.0x10(-6), and 6.3x10(-6) M) was given before and after double-blind celiprolol (0.30 mg/kg IV), atenolol (0.15 mg/kg IV), or placebo in 3x12 patients. Vasomotion was investigated by quantitative coronary angiography in proximal and distal segments of epicardial coronary arteries, and by the determination of the coronary resistance index based on Doppler-flow measurements. The investigated drugs had no direct affect on the diameter of the epicardial coronary arteries. However, celiprolol, in contrast to atenolol, significantly reduced systemic vascular resistance (change after atenolol: from 1,855+/-308 to 2,161+/-550 dyne s cm(-5); celiprolol: 1,691+/-435 to 1,411+/-343 dyne s cm(-5); and placebo: 1,722+/-215 to 1,710+/-213 dyne s cm(-5), p<0.001) and the coronary resistance index (change after atenolol: 2.52+/-3.58 to 2.86+/-4.24; celiprolol: 2.70+/-1.55 to 2.49+/-2.26; and placebo: 1.97+/-1.35 to 1.92+/-1.25, p<0.01). Celiprolol, atenolol, and placebo did not have different effects on acetylcholine-induced coronary vasomotion of epicardial conductance vessels (diminution of proximal lumen diameter before/after atenolol: 0.42+/-0.39/0.44+/-0.39 mm; celiprolol: 0.32+/-0.26/0.30+/-0.24 mm; and placebo: 0.36+/-0.29/0.43+/-0.40 mm) and of coronary resistance vessels (reduction of coronary resistance index before/after atenolol: 1.95 +/-4.74/ 1.92+/-3.74; celiprolol: 0.98+/-0.73/1.41+/-1.50; and placebo: 1.16+/-1.29/1.16+/-1.04). In contrast to atenolol, celiprolol possesses vasodilative properties in systemic and coronary resistance vessels. There was no direct effect on the diameter of conductance vessels. Acetylcholine-induced coronary vasomotion both in conductance and resistance vessels was not influenced by the beta blockers that were studied. This suggests that atenolol and celiprolol do not influence endothelium-dependent, nitric oxide related vasomotion.

Serial evaluation of left ventricular function by radionuclide ventriculography at rest and during exercise after orthotopic heart transplantation

Discrepant results have previously been reported concerning long-term left ventricular function in the human transplanted heart as assessed by radionuclide ventriculography. In this study, radionuclide ventriculograms were obtained at rest and during exercise in 19 patients <6 months, 7–12 months, 13–24 months and >24 months after transplantation. Ejection fraction decreased significantly from <6 months to 13–24 months after transplantation (rest: 69.1%±9.7% to 56.7%±8.3%, P<0.05; exercise: 70.4%±11.3% to 59%±8%, P<0.05). Heart rate increased significantly during exercise after >2 years (90.2±10.5 beats/min to 103.5±15 beats/min, P<0.05) but not within 6 months after transplantation (98.5±12.8 beats/min to 99.07±15.8 beats/min). Left ventricular end-diastolic volume remained unchanged. Peak filling rate at rest decreased significantly from 4.2±0.96 edv/s <6 months after transplantation to 3.3±0.66 edv/s (P<0.05) 13–24 months and 3.3±0.64 edv/s (P<0.05)>24 months after cardiac transplantation. Exercise peak filing rate did not change significantly. It is concluded that radionuclide ventriculography demonstrates a decrease in systolic left ventricular function in the long-term course after cardiac transplantation. A significant increase in exercise peak heart rate may be due to autonomic reinnervation. Differences in the literature concerning left ventricular function may be due to different observation intervals following cardiac transplantation.

Endothelium-dependent and endothelium-independent flow regulation in coronary vascular regions supplied by arterial and venous bypass grafts

The endothelium-dependent and endothelium-independent vasodilation of arterial and venous coronary bypass grafts and of epicardial conduit vessels and microcirculatory coronary vessels supplied by these grafts was investigated. Vasodilatory response and flow regulation were tested with cumulative intracoronary doses of acetylcholme (25 and 50 µg i.e.), nitroglycerin (0.3 mg i.e.), and papaverine (10 mg i.e.) in 10 patients (age 60 ± 2.3 years) with arterial grafts and in 16 patients (age 57.7 ± 1.5 years) with venous grafts. The effect of acetylcholme on arterial and venous bypass grafts and on large conduit arteries was evaluated by quantitative coronary angiography. Coronary blood flow velocity changes as a parameter of microcirculatory function were measured by intraluminal Doppler ultrasound. Indices for coronary flow and coronary resistance were calculated from the mean Doppler flow velocity and the computed cross-sectional vascular area. The coronary resistance decreased endothelium dependent after 25 and 50 µg of acetylcholme by 16 ± 30% (p

Variations of segmental endothelium-dependent and endothelium-independent vasomotor tone after cardiac transplantation (qualitative changes in endothelial function)

Endothelial dysfunction is a common phenomenon after cardiac transplantation. However, qualitative differences in endothelial vasoregulation at different coronary segments and at different postoperative times have rarely been explored. To uncover the functional variations of endothelium responses we infused the endothelium-dependent vasodilator acetyl-choline (50 micrograms) followed by the endothelium-independent vasodilator 3-morpholinosydnonimine (SIN-1) (1 mg; 16 patients) or nitroglycerin (0.3 mg; 14 patients) sequentially into the left coronary artery. We investigated the responses of 120 nonstenotic coronary segments (proximal and distal left anterior descending and right circumflex coronary arteries) in 30 patients with quantitative angiography (group 1: 13 patients, 12 +/- 1 months after cardiac transplantation; group 2: 17 patients, 55 +/- 3 months after cardiac transplantation). Continuous-flow measurement was performed to exclude significant reduction of microvascular response influencing epicardial dilation. Five responses to acetylcholine administration followed by nitrates were observed. On the one end of the spectrum, segments dilate to acetylcholine administration with no further dilation to exogenous nitric oxide, indicating completely preserved endothelial function. On the other end, segments constrict to acetylcholine with no change after endogenous nitric oxide, reflecting a defective endothelial and defective smooth muscle function. The different patterns of coronary vasomotor lone responses to endogenous nitric oxide followed by exogenous nitric oxide represent different degrees of endothelial function after cardiac transplantation. In addition, the functional assessment of endothelial integrity shows qualitative time-dependent differences between proximal and distal coronary parts. The existence of coronary segments with functioning endothelium indicates that the latter is not diffusely disturbed in all cardiac transplant recipients and that the endothelial damage is perhaps not irreversibly lost.

Successful Thrombolysis After Prosthetic Pulmonary Valve Obstruction Under Aspirin Monotherapy

In a 22-year-old woman with recent onset of left-sided chest pain and exertional dyspnea, echocardiography revealed obstruction of a St. Jude Medical bileaflet prosthetic valve (size 23 mm) in the pulmonary position. Oral anticoagulation had been replaced for the previous 7 years by aspirin as the sole antithrombotic treatment. The valve had been inserted 16 years ago for pulmonary atresia. Valve function was restored by systemic application of 9 million units of urokinase.

Right ventricular volumes determined by computerized thermodilution in ischaemic heart disease : effect of exercise and nitroglycerin

In 29 patients with stable ischaemic heart disease, right heart catheterization was performed to assess the effect of exercise and nitroglycerin on right ventricular volumes, which were determined by a new computerized thermodilution system. The coefficient of variation for the determination of right ventricular ejection fraction averaged 11.0 +/- 6.2% (mean +/- standard deviation) at rest and 14.6 +/- 8.1% during exercise. End-diastolic volume index increased from 90 (65-127) ml/m2 [median (range)] at rest to 101 (81-130) ml/m2 (P less than or equal to 0.0001) during exercise. Nitroglycerin reduced this parameter at rest to 77 (44-121) ml/m2 (P less than or equal to 0.05), without affecting exercise values. Resting right ventricular ejection fraction (55 [44-64]%) was diminished by both exercise (to 52 [39-62]%, P less than or equal to 0.05) and nitroglycerin (to 53 [40-65]%, P less than or equal to 0.05). Additionally, nitroglycerin reduced the exercise induced decrease of right ventricular ejection fraction from -3 (-20-10)% to -1 (-15-14)% (P less than or equal to 0.01). Nitroglycerin diminished the left-to-right interventricular end-diastolic pressure gradient, which was estimated from the difference between pulmonary capillary wedge pressure and right atrial pressure, at rest from 6 (1-17) mmHg to 5 (2-14) mmHg (P less than or equal to 0.05) and during exercise from 17 (6-31) mmHg to 14 (1-33) mmHg (P less than or equal to 0.001). It is concluded, that both exercise and nitroglycerin cause significant changes in right ventricular volumes.(ABSTRACT TRUNCATED AT 250 WORDS)

Endothelium-dependent and endothelium-independent flow reserve in vascular regions supplied by the internal mammary artery before and after bypass grafting

OBJECTIVE It was the goal of this study to compare endothelium-dependent and endothelium-independent flow reserve in vascular regions supplied by the left internal mammary artery before and after bypass graft surgery. METHODS The native internal mammary artery in situ was investigated in 13 patients (age 61.8 +/- 8.0 years) with angiographically proven coronary artery disease. The internal mammary artery after bypass grafting was investigated in ten patients (age 60.8 +/- 7.3 years) 3.5 +/- 2.8 years after the operation. Flow reserve was evaluated endothelium-dependent with acetylcholine (ACh 25 and 50 microg i.c.) and endothelium-independent with nitroglycerin (NTG 0.3 mg i.c.) followed by papaverin (10 mg i.c.). Flow indices were calculated from intraluminal Doppler blood flow velocity measurements and the vascular cross-sectional area as determined by quantitative angiography. An index for vascular resistance was defined as the ratio of pressure gradient and resting or peak flow. RESULTS After endothelium-dependent stimulation with acetylcholine 25 microg (50 microg), flow in the internal mammary increased by 352.3 +/- 152% (412 +/- 145%) before surgery, whereas it increased only by 213 +/- 134% (193 +/- 120%) after surgery (P < 0.05). Endothelium independent stimulation with papaverin resulted in a flow increase of 391 +/- 234% before surgery vs. 315 +/- 135% after surgery (n.s.). The resistance index decreased after endothelium-dependent stimulation with acetylcholine 25 microg(50 microg) to 35 +/- 16.8% (28 +/- 8.9%) before surgery, whereas it decreased only to 59 +/- 26% (72 +/- 43%) after surgery (P < 0.05). Endothelium independent stimulation with papaverin resulted in a decrease of the vascular resistance index to 31 +/- 14% before surgery vs. 32 +/- 14% after surgery (n.s.). CONCLUSION Vascular regions supplied by the internal mammary artery as a graft demonstrate a significantly reduced endothelium-dependent flow reserve but a preserved endothelium-independent flow reserve as compared to vascular regions supplied by the native internal mammary artery. The selective decrease in endothelium-dependent flow reserve may be due to microvascular changes in the myocardial region supplied by the internal mammary artery after bypass grafting.