Images in clinical medicine. Cardiac constriction due to a calcified pericardium.
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Aged↗
Biomedical subjects
Claudia Walther
Publications and source records attributed to Claudia Walther.
Reverse remodeling of cardiac collagen protein expression after surgical therapy for experimental aortic stenosis.
BACKGROUND AND AIM OF THE STUDY: Reversal of myocardial collagen gene expression was examined in parallel to left ventricular reverse remodeling after surgical correction of experimental aortic stenosis. METHODS: A standard growing sheep model (age at baseline 6-8 months) was used. Measurements were performed at baseline (point A) when inducing left ventricular hypertrophy (LVH) through supracoronary banding, at 8.3 +/- 1.0 months later at surgical correction (point B), and after another 10.1 +/- 2.0 months during final examinations (point C). Gene expression for collagen I and III was also studied. RESULTS: Left ventricular function was stable throughout the study. The left ventricular mass index (LVMI) was 82 +/- 21 g/m2 at point A, 150 +/- 33 g/m2 at B, and 78 +/- 18 g/m2 at C (p <0.01). Myocardial fiber diameter was 11.3 +/- 0.8, 15.9 +/- 1.2 and 11.4 +/- 1 microm at points A, B and C, respectively (p <0.01). Protein expression for collagen I was 0.71 +/- 0.2 (at A), 1.13 +/- 0.3 (at B) and 0.85 +/- 0.4 (at C) (p <0.01), while that for collagen III was 0.72 +/- 0.4 (at A), 1.26 +/- 0.8 (at B) and 0.83 +/- 0.3 (at C) (p <0.01). There was a significant correlation between changes in LVMI and myocardial collagen expression. CONCLUSION: Complete reverse remodeling with regression of LVH and myocardial collagen protein expression can be anticipated after surgical correction of experimental aortic stenosis.
Animals↗
Changes in myocardial perfusion due to physical exercise in patients with stable coronary artery disease.
PURPOSE: Percutaneous transluminal coronary angioplasty (PTCA) is one of the main therapy options for patients with coronary artery disease (CAD), resulting in an improvement in myocardial perfusion and exercise capacity. Nevertheless, studies have also demonstrated a positive effect of regular exercise training on myocardial perfusion and maximum exercise capacity. The aim of this study was to evaluate changes in myocardial stress perfusion after 1 year of exercise training in comparison with the effects of PTCA in patients with CAD. METHODS: In 66 male patients with angiographically confirmed significant coronary artery stenosis in one target vessel, myocardial perfusion scintigraphy was performed at baseline and 12 months after randomisation into either a physical exercise group or a PTCA group. Circumferential count rate profiles in 16 wall segments were classified according to their relative count rate and localisation within or outside the area supplied by the stenosed vessel. RESULTS: Ischaemic segments showed a significant improvement in myocardial count rate within the target area after 12 months in both the PTCA and the training group (PTCA group: from 76.8+/-4.9% to 86.6+/-10.9%, p=0.03; training group: from 74.0+/-7.3% to 83.7+/-10.8%, p<0.01). Outside the target area only the training group showed a significant improvement (from 77.7+/-4.4% to 91.7+/-4.8%, p<0.01). CONCLUSION: Our data indicate a significant improvement in stress myocardial perfusion in the training group after 12 months. The ischaemia is reduced not only in the target region of the leading stenosis but also in other ischaemic myocardial areas. In contrast, after PTCA stress perfusion improves only in the initially ischaemic parts of the target area.
Adult↗
Clinical experience with stentless mitral valve replacement.
BACKGROUND: Our aim is to describe the clinical experience with stentless mitral valve (SMV) replacement with special focus on the functionality of the SMV. METHODS: Fifty-two patients (68 +/- 8.5 years old; 36 female) have been prospectively evaluated since August 1997. The chordally supported SMV (Quattro) was implanted for mitral stenosis (n = 26), severe incompetence (n = 17), or mixed lesion (n = 9). Preoperative New York Heart Association class was 3.1 +/- 0.6. Twenty patients received additional intraoperative ablation therapy. Mean follow-up is 37.3 +/- 18.7 months (range, 1 to 65). RESULTS: Surgery was performed using conventional sternotomy (33) or anterolateral minithoracotomy (19). Atrial rhythm was reestablished in 17 of 20 patients. Six patients operated on early in this series required reoperation, 2 for paravalvular leakage, 2 for functional stenosis, 1 with pannus formation due to underlying rheumatoid disease, and 1 for papillary flap rupture after 5.1 years. Mortality was 1 perioperative (1.9%, nonvalve related) and 1 after reoperation due to multiorgan failure. During late follow-up (30 +/- 7 months postoperatively) 5 patients died of noncardiac causes. Regular echocardiographic control revealed good SMV function (maximum transmitral blood flow velocity 1.7 +/- 0.2 m/s; mean transmitral pressure gradient 3.9 +/- 1.2 mm Hg) and well-preserved ejection fraction postoperatively as well as at most recent follow-up. CONCLUSIONS: The clinical experience after 5.5 years of SMV implantation is promising. Preservation of annuloventricular continuity is advantageous. However, long-term durability remains to be proved.
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Percutaneous coronary angioplasty compared with exercise training in patients with stable coronary artery disease: a randomized trial.
BACKGROUND: Regular exercise in patients with stable coronary artery disease has been shown to improve myocardial perfusion and to retard disease progression. We therefore conducted a randomized study to compare the effects of exercise training versus standard percutaneous coronary intervention (PCI) with stenting on clinical symptoms, angina-free exercise capacity, myocardial perfusion, cost-effectiveness, and frequency of a combined clinical end point (death of cardiac cause, stroke, CABG, angioplasty, acute myocardial infarction, and worsening angina with objective evidence resulting in hospitalization). METHODS AND RESULTS: A total of 101 male patients aged < or =70 years were recruited after routine coronary angiography and randomized to 12 months of exercise training (20 minutes of bicycle ergometry per day) or to PCI. Cost efficiency was calculated as the average expense (in US dollars) needed to improve the Canadian Cardiovascular Society class by 1 class. Exercise training was associated with a higher event-free survival (88% versus 70% in the PCI group, P=0.023) and increased maximal oxygen uptake (+16%, from 22.7+/-0.7 to 26.2+/-0.8 mL O2/kg, P<0.001 versus baseline, P<0.001 versus PCI group after 12 months). To gain 1 Canadian Cardiovascular Society class, 6956 dollars was spent in the PCI group versus 3429 dollars in the training group (P<0.001). CONCLUSIONS: Compared with PCI, a 12-month program of regular physical exercise in selected patients with stable coronary artery disease resulted in superior event-free survival and exercise capacity at lower costs, notably owing to reduced rehospitalizations and repeat revascularizations.
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The effect of exercise training on endothelial function in cardiovascular disease in humans.
Endothelial dysfunction occurs early in atherosclerosis in response to cardiovascular risk factors. The occurrence of endothelial dysfunction is primarily the result of reduced nitric oxide (NO) bioavailabilty. It represents an independent predictor of cardiovascular events and predicts the prognosis of the patient. Therefore, endothelial function has been identified as a target for therapeutic intervention. Regular exercise training is a nonpharmacological option to improve endothelial dysfunction in patients with cardiovascular disease by increasing NO bioavailability.
Cardiovascular Diseases↗
Early results with stentless mitral valve replacement.
BACKGROUND AND AIM OF THE STUDY: Implantation of a chordally supported stentless mitral valve (SMV) may be the strategy of choice for patients with severe degenerative mitral valve disease. Herein, the early clinical results of this surgical technique were analyzed. METHODS: Since August 1997, 52 patients (36 females, 16 males; mean age 68.0 +/- 8.5 years) each received a SMV (Quattro; St. Jude Medical Inc.) at the authors' institution. The underlying disease was predominant mitral stenosis (n = 26), incompetence (n = 17) and combined lesion (n = 9). The mean NYHA class was 3.1 +/- 0.6, left ventricular ejection fraction 64 +/-13%, and cardiac index 2.1 +/- 0.8 1/min/m2. RESULTS: SMV implantation was performed using either a conventional sternotomy (n = 33) or a lateral minithoracotomy (n = 19). The mean implanted valve size was 29.2 +/- 1.7 mm, and mean cross-clamp time 81 +/- 33 min. Reoperation was required in six patients: two for paravalvular leakage, two for functional stenosis (both 26 mm valves), in one patient for pannus formation with underlying collagenosis, and in one for papillary flap rupture at five years. One patient died perioperatively, one died after reoperation at one year, and five patients died at longer follow up, from non-cardiac causes. Hemodynamic function was shown to be normal on echocardiography. CONCLUSION: Intermediate-term results after SMV implantation were promising. Preservation of annuloventricular continuity led to good left ventricular function, but long-term durability remains to be proven.
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Midterm results after stentless mitral valve replacement.
BACKGROUND: To analyze the midterm clinical results after stentless mitral valve (SMV) replacement. METHODS AND RESULTS: Fifty one patients (68.3+/-8.4 years, 35 female) with severe mitral valve disease (stenosis 25, incompetence 17, mixed lesion 9) received a chordally supported SMV (Quattro, St. Jude Medical Inc.) since August 1997. Preoperative New York Heart Association class was 3.1+/-0.6; left ventricular ejection fraction 64+/-13%, and cardiac index 2.1+/-0.8 l/min/m2. Additional intraoperative ablation therapy was performed on 19 patients with chronic atrial fibrillation. Mean follow-up is 35.4+/-19.2 months (range 5 to 63). SMV implantation was performed using a conventional (32) or a minimally invasive (19) approach, valve size was 29+/-1.5 mm, cross-clamp duration was 81+/-33 minutes. Atrial rhythm was reestablished in 16 of 19 patients. Five patients required reoperation early in this series, two for paravalvular leakage, two for functional stenosis, and one with underlying rheumatoid disease. Mortality was one perioperative (1.96%, non-valve-related), one after reoperation as a result of multiple organ failure (MOF), and five during late follow-up (30+/-7 months postoperatively) for noncardiac causes. Regular echocardiographic control revealed good SMV function (Vmax 1.7+/-0.2m/s, P(mean) 3.9+/-1.2 mm Hg) and well-preserved ejection fraction postoperatively and at most recent follow-up. CONCLUSIONS: Midterm results after SMV implantation are promising. Preservation of the annuloventricular continuity leads to stable left ventricular function and combined with ablation therapy to physiological hemodynamics. Long-term durability remains to be proven.
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Facilitated endoscopic beating heart coronary artery bypass grafting using a magnetic coupling device.
BACKGROUND: Suturing of a coronary anastomosis in totally endoscopic coronary artery bypass grafting on the beating heart is technically demanding. The potential benefits of the endoscopic Magnetic Vascular Positioner device (Ventrica, Inc, Fremont, Calif) to facilitate construction of a coronary anastomosis in a closed chest environment were evaluated. METHODS: Totally endoscopic coronary artery bypass grafting on the beating heart was performed in 8 foxhound-beagle inbred dogs with the da Vinci telemanipulation system (Intuitive Surgical, Mountain View, Calif). A prototype of the endoscopic Magnetic Vascular Positioner device was used to facilitate construction of the coronary anastomosis. One pair of magnets was inserted in the internal thoracic artery and left anterior descending artery using robotic instruments to guide and place the endoscopic delivery platform. All animals underwent angiography; gross inspection of the anastomotic site was performed after excision of the hearts. RESULTS: The procedure was accomplished in all animals in 169 minutes (155-190 minutes). Dissection of the left anterior descending coronary artery (6.5 minutes; 1-20 minutes), positioning of the stabilizer (8.5 minutes; 7-16 minutes), placement of occlusion tapes (6 minutes, 3-10 minutes), and arteriotomy 5.5 minutes (3-30 minutes) was achieved without problems. By use of the Magnetic Vascular Positioner device, the anastomosis at the graft site was performed with the graft still in situ. Except for 1 premature deployment, all other deployments were easily accomplished in 3 minutes (1-28 minutes). The following adverse events were encountered: bleeding from the right ventricle caused by occlusion tape (1), anastomotic leakage on reperfusion requiring repair stitches (2), and anastomotic occlusion as a result of thrombus (1). All except 1 animal with a patent graft and anastomosis survived the procedure. The overall patency was 7 of 8. DISCUSSION: The combination of robotic technology allowing for dexterous manipulation in a closed chest environment and a simple yet effective and timesaving technique for anastomotic coupling may facilitate beating heart totally endoscopic coronary artery bypass grafting.
Anastomosis, Surgical↗
Exercise training in patients with severe chronic heart failure: impact on left ventricular performance and cardiac size. A retrospective analysis of the Leipzig Heart Failure Training Trial.
BACKGROUND: Exercise training (ET) has been shown to improve functional work capacity in patients with stable chronic heart failure (CHF) having moderate symptoms (NYHA class II). This analysis was conducted, to evaluate the effects of ET on left ventricular function and haemodynamics in patients with advanced CHF (NYHA class III) fulfilling the inclusion criteria of the COPERNICUS trial. METHODS: Seventy-three patients with moderate and advanced CHF were prospectively randomised to a training (n=36), or to a control group (n=37). At baseline and after six months, patients underwent echocardiography and symptom-limited ergospirometry with measurement of central haemodynamics by thermodilution. RESULTS: Nine out of 37 patients in the control group (C) and 10 out of 36 patients in the training group (T) had symptoms of advanced CHF. Exercise training over a period of six months resulted in an improvement of functional status on average by one NYHA class in patients with advanced CHF. Moreover, oxygen uptake at the ventilatory threshold increased by 49% (from 7.7+/-1.0 to 11.4+/-0.4 mL/min/kg, P<0.01 versus baseline) and at peak exercise by 32% (from 16.3+/-1.6 to 21.5+/-1.2 mL/min/kg, P<0.01 versus baseline) in training patients. The small, but significant reduction in left ventricular end-diastolic diameter by 7% (from 70+/-2 to 66+/-2 mm; P<0.05 versus baseline) was accompanied by an augmentation in stroke volume at rest by 32% (from 45+/-3 to 60+/-6 mL, P<0.05 versus baseline) and at peak exercise by 27% (63+/-9 to 81+/-9 mL, P<0.05 versus baseline) as a result of ET in patients with advanced CHF. CONCLUSIONS: In patients with advanced CHF (NYHA class III), long-term exercise training is associated with an enhanced physical work capacity, an improvement in stroke volume and a reduction in cardiomegaly.
Cardiomegaly↗
Left ventricular reverse remodeling after surgical therapy for aortic stenosis: correlation to Renin-Angiotensin system gene expression.
BACKGROUND: Surgical therapy for aortic stenosis leads to reverse remodeling, with normalization of left ventricular hypertrophy (LVH). The aim of this study was to examine Renin-Angiotensin system (RAS) gene expression in this setting. METHODS: Growing sheep (n=44) underwent supracoronary aortic banding for controlled induction of LVH at the age of 6 to 8 months (A=baseline). Surgical revision to completely release the pressure gradient was performed 8.3+/-1 months later (B). The animals were sacrificed after another 10.1+/-2 months (C). Along with hemodynamic measurements, subtractive hybridization and competitive polymerase chain reaction were applied to quantify mRNA expression for angiotensin-converting enzyme (ACE) and angiotensin receptors 1 and 2 (AT1-R and AT2-R). RESULTS: Left ventricular mass index was 82+/-21 g (A), 150+/-33 g (B), and 78+/-18 g (C), P<0.01. Left ventricular function and cardiac index remained stable. Myocardial fiber diameter was 11.3+/-0.8 (A), 15.9+/-1.2 (B), and 11.4+/-1 (C) microm, P<0.01. Gene expression was as follows: ACE 0.8+/-0.05 (A), 1.3+/-0.08 (B), and 0.9+/-0.06 (C), P<0.01; AT1-R 0.7+/-0.06 (A), 0.9+/-0.07 (B), and 0.3+/-0.04 (C), P<0.01; AT2-R 0.5+/-0.05 (A), 0.2+/-0.04 (B), and 0.5+/-0.05 (C), P<0.01. CONCLUSION: LVH in aortic stenosis coincides with significant alterations of the RAS. Surgical therapy leads to reverse remodeling, which is paralleled by regression of RAS gene expression.
Animals↗
Two non-complementing genes encoding enzymatically active methylenetetrahydrofolate reductases control methionine requirement in fission yeast Schizosaccharomyces pombe.
By transforming two methionine auxotrophic mutants from fission yeast Schizosaccharomyces pombe with a wild-type gene library, we defined two genes, met9 and met11, which both encode a methylenetetrahydrofolate reductase. The genes cannot complement each other. We detected single transcripts for both. In vitro measurements of enzymatic activities showed that the met11-encoded enzyme was responsible for only 15-20% of the total methylenetetrahydrofolate reductase activity. A strain in which gene met9 was disrupted required significantly more methionine for full growth and efficient mating and sporulation than the strain disrupted for gene met11. The in vitro and in vivo data thus indicated that met9 was the major expressed gene. Our results are in accordance with the assumption that the two methylenetetrahydrofolate reductases generate the methyl groups necessary for methionine synthetase to convert homocysteine to methionine, and suggest that expression of the two genes is an important parameter in the control of methionine biosynthesis.
Blotting, Northern↗
Hemodynamic evaluation of stentless mitral valve replacement.
The purpose of this study was to evaluate the perioperative and postoperative hemodynamic function of recently introduced stentless mitral valves (SMVs). Forty-two selected patients who had received the SMV since 1997 had preoperative, postoperative, and follow-up transthoracic echocardiographic (TTE) examinations. Transesophageal echocardiography (TEE) was applied routinely during the operation as well as postoperatively if indicated. Adequate SMV function was seen in all patients perioperatively. Echocardiographic prediction of valve size and of papillary muscle distances was correct in 37 of 42 patients. Transvalvular blood flow velocities were 1.6 +/- 0.2 m/s postoperatively versus 1.8 +/- 0.3 m/s at 1 year and 1.7 +/- 0.3 m/s at 3-year follow-up. Mean transvalvular gradients were 4.3 +/- 1.6, 3.8 +/- 1.9, and 4.7 +/- 1.1 mm Hg, respectively. TEE and TTE are extremely useful to assist SMV implantation as well as for regular follow-up evaluation. The hemodynamic function after SMV implantation with preservation of the annulo-ventricular continuity is promising.
Aged↗
Anti-inflammatory effects of physical exercise. A new mechanism to explain the benefits of cardiac rehabilitation?
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C-Reactive Protein↗