Hemodynamic changes during retrograde left-heart catheterization in patients with aortic stenosis

Pulmonary artery pressures in patients with aortic stenosis have been related to postoperative prognosis and surgical risk. However, while right- and left-heart pressures should be measured simultaneously, a catheter lying across the stenotic aortic valve might alter left- and right-heart pressures. To assess this phenomenon, right- and left-heart pressures were recorded before and after retrograde crossing of the aortic valve in 51 patients (30 patients with and 21 without aortic stenosis). In aortic stenosis, the mean pulmonary artery pressure increased (p less than 0.001) after transaortic valvular pressure catheter placement (average 4 mm Hg, peak 19 mm Hg); in the absence of aortic stenosis, the mean pulmonary artery pressure did not change (average 0 mm Hg; NS). A similar response was noted for the mean pulmonary capillary wedge pressure. Hemodynamic changes did not correlate with the severity of aortic stenosis or with left ventricular performance. Right-heart pressures should be determined without transaortic valvular catheter in place, if accurate interpretation of the hemodynamic effects of aortic stenosis is to be achieved.     

Angeborene Herzfehler und erworbene Herzklappenfehler in der Schwangerschaft

BACKGROUND: In Germany, about 6,000 pregnancies in women with grown-up congenital heart disease or acquired valvular lesions are expected per year. The pregnancy-related physiology is characterized by a 50% increase in plasma volume and a 25% increase in erythrocyte volume. The cardiac output increases by 40% due to 30% increase in stroke volume and 10% increase in heart rate during the first half, and 10% increase in stroke volume but 30% increase in heart rate during the second half of pregnancy. As a consequence of the decrease of systemic vascular resistance, the systolic and, even more, the diastolic blood pressures are reduced during approximately the first 20 weeks of pregnancy. UNCORRECTED CONGENITAL LESIONS: Women with uncorrectable congenital heart disease, congestive heart failure (NYHA III and IV) despite optimized medical treatment after palliative surgery, or pulmonary vascular resistances > 800 dyn x s x cm(-5) should be advised against pregnancy. The presence of congestive heart failure or persistent cyanosis in the mother are the most important predictors of fetal hypoxia. Patients with pretricuspid shunts (e.g., atrial septal defect [ASD]) are at low risk of a hemodynamic deterioration or first onset of arrhythmias. In the rare case of a marked clinical deterioration, catheter-based closing of the shunt is the first-line treatment. Also, ventricular septal defects and persistent ducti arteriosi are usually well tolerated during pregnancy, as they are highly resistant to flow. In some cases, arrhythmias may occur. The prognosis is less favorable, if myocardial compromise has already been present before pregnancy. The fatal complication rate correlates closely with the degree of congestive heart failure. In aortic coarctation, development of severe hypertension, myocardial decompensation, aortic dissection, and cerebral hemorrhage have been reported in 2.3% of cases. To prevent aortic dissection and rupture of cerebral vascular aneurysms, patients should be advised to reduce their physical activity and have their blood pressure controlled closely. If, during pregnancy, a therapeutic intervention is unavoidable, stent placement is the therapy of choice. The maternal complication rate is low in pulmonary artery stenosis. Hemodynamically significant stenoses should be treated before pregnancy. In the rare case of progressive right heart failure or cyanosis during pregnancy, balloon valvotomy is the first-line therapeutic option. CONGENITAL HEART DISEASE WITH PRIOR PALLIATION: Women with incomplete correction of a tetralogy of Fallot or significant residual gradients or shunts carry a particular risk of myocardial deterioration. A maternal hematocrit > 60%, an arterial O(2) saturation < 80%, markedly elevated right ventricular pressures, and the former presentation of syncopes are indicators of a poor prognosis. Fatal complication rates have been reported in 3-17% of cases. Other cyanotic lesions have been linked with a poor maternal and fetal prognosis. A 32% incidence of severe cardiovascular complications (pump failure, thromboembolic events, life-threatening arrhythmias, infective endocarditis) has been reported during 96 pregnancies of women with cyanotic heart disease. In addition, the frequency of abortions, premature birth, fetal distress, and congenital malformation of the child was 57%. ACQUIRED VALVE LESIONS: Mitral stenosis is the lesion that most frequently requires therapeutic intervention during pregnancy, as the transmitral flow increases and time of diastole decreases during pregnancy due to the increase in cardiac output and heart rate. A consequent increase in mean pulmonary artery pressure by approximately 50% and a deterioration by one to two NYHA classes must be expected. While patients with a mitral orifice area > 1.5 cm(2) can usually be treated medically, more advanced mitral stenoses often require percutaneous mitral balloon valvotomy, a procedure with a very low complication rate in experienced centers. A chronic mitral or aortic regurgitation without jeopardized myocardial function is usually well tolerated during pregnancy, as the drop in peripheral vascular resistance results in a favorable left ventricular impedance, which reduces the transmitral regurgitant fraction and improves left ventricular antegrade ejection. Moreover, the increase in heart rate limits diastolic transaortic regurgitation. Hemodynamically advanced aortic stenosis is rare among patients in child-bearing age. The hemodynamic changes during pregnancy result in a decrease of the transaortic flow per time and thus in a decrease of the transaortic pressure loss. On the other hand, myocardial wall stress and oxygen consumption are significantly increased. If aortic valve orifice area is > 1.5 cm(2), the hemodynamic situation is usually well tolerated during pregnancy. In the case of more advanced aortic stenosis, there is a considerable risk of myocardial decompensation. The development of symptoms such as dyspnea, near syncopes or syncopes, and arrhythmias are indicators of a complicated course. If treatment is unavoidable, aortic valve replacement is the therapy of choice. ORAL ANTICOAGULATION: With respect to anticoagulation during pregnancy, there is an ongoing debate about the potential risk and benefit of phenprocoumon, standard heparins, and low molecular heparins. Withdrawal of any anticoagulation results in the most favorable fetal outcome, oral anticoagulation throughout pregnancy in the best prognosis for the mother. An individual approach by an experienced center taking all therapeutic options into account is probably the best strategy.     

Echocardiographic assessment of left ventricular function in aortic valve disease.

Echocardiography was used to study left ventricular size and contraction in 128 patients with isolated aortic valve disease -45 patients with aortic stenosis, 25 with mixed aortic valve disease and 58 with aortic regurgitation. Left ventricular measurements included the end-diastolic internal dimension (LVIDd), mural thickness (PWTd), an index of circumferential myocardial contraction-fractional shortening (FS=[(LVIDd-LVIDs)/LVIDd] X 100)--and stroke volume (LVSV). In the absence of left ventricular failure, measurements in aortic stenosis were characteristic of pressure overload with normal LVIDd and FS and an increase in PWTd related to the severity of stenosis; in aortic regurgitation, there was volume overload with increases in LVIDd and PWTd which were related to the severity of regurgitation, while FS was slightly reduced. In mixed aortic valve disease there was evidence of both pressure and volume overload. When left ventricular failure was associated with aortic stenosis, mixed aortic valve disease and chronic aortic regurgitation, FS was usually reduced. By contrast, in a recent patient with acute severe aortic regurgitation, FS was normal despite left ventricular failure, suggesting pump rather than myocardial failure.     

Der „asymptomatische“ Patient mit chronischem Herzklappenfehler

An intervention for chronic acquired valvular heart disease may either be indicated in symptomatic patients to relieve symptoms and improve quality of life or in asymptomatic patients to improve long-term prognosis, e.g., by preventing disease-related complications like chronic heart failure or arrhythmias. For proper action according to current guidelines, the systematic evaluation of symptoms related to the underlying valve disease is of utmost importance. If a discrepancy between symptoms reported or not reported by the patients and the severity of the valve disease is supposed, true absence of symptoms and exercise tolerance should be verified by spiroergometry. In the truly asymptomatic patient with a severe valvular lesion, preservation of myocardial adaption to the chronic volume or pressure overload should be tested utilizing appropriate imaging techniques like radionuclide ventriculography under exercise conditions. The proper evaluation of the functional status is of growing importance in our aging population with its sedentary lifestyle. In this context, the results of a survey should be kept in mind, which indicated that a significant proportion of patients still have interventions too late during the natural history of their valve disease with symptoms of congestive heart failure, arrhythmias, and the risk of sudden cardiac death persisting after a primarily successful valve repair or replacement.     

Doppler echocardiographic evaluation of aortic stenosis

Doppler echocardiography allows accurate noninvasive measurement of transaortic velocity and pressure gradient in patients with valvular aortic stenosis. Because pressure gradients vary with transaortic volume flow, calculation of aortic valve area with the continuity equation is essential for complete echocardiographic evaluation of adult patients. The physician and sonographer should be aware of potential technical and physiologic pitfalls in applying Doppler echocardiographic techniques to the evaluation of the adult with aortic stenosis. With proper training and experience, however, the needed data can be obtained reliably and reproducibly. Doppler evaluation of patients with aortic stenosis has improved our understanding of the prevalence and natural history of this disease. In addition, Doppler measures of stenosis severity can be used in a cost-effective manner for clinical decision making regarding the need for valve replacement in symptomatic adults. It now has supplanted the need for invasive measures of stenosis severity in many of these patients.     

The Role of Jet Eccentricity in Generating Disproportionately Elevated Transaortic Pressure Gradients in Patients with Aortic Stenosis

In patients with aortic stenosis (AS) and eccentric transaortic flow, greater pressure loss occurs as the jet collides with the aortic wall together with delayed and diminished pressure recovery. This leads to the elevated transaortic valve pressure gradients noted on both Doppler and cardiac catheterization. Such situations may present a diagnostic dilemma where traditional measures of stenosis severity indicate severe AS, while imaging modalities of the aortic valve geometric aortic valve area (GOA) suggest less than severe stenosis. In this study, we present a series of cases exemplifying this clinical dilemma and demonstrate how color M‐mode, 2D and 3D transthoracic (TTE) and transesophageal (TEE) echocardiography, cardiac computed tomography angiography (CTA), and magnetic resonance imaging (MRI), may be used to resolve such discrepancies.     

Noninvasive estimation of the left ventricular pressure waveform throughout ejection in young patients with aortic stenosis

Validation of a totally noninvasive method for estimating instantaneous left ventricular pressure and constructing a pressure waveform throughout ejection in patients with aortic stenosis is reported. In 20 patients (aged 8.75 +/- 10 years) with congenital aortic stenosis (measured peak left ventricular pressure 120 to 260 mm Hg; transvalvular gradient 18 to 165 mm Hg), transaortic valve continuous wave Doppler ultrasound, indirect carotid pulse tracing, peripheral blood pressure and measured left ventricular pressure were recorded simultaneously at cardiac catheterization. Data were entered into a microcomputer using a digitizing tablet and the instantaneous Doppler gradient was calculated and added to instantaneous aortic pressure, derived from the time-corrected and calibrated carotid pulse tracing, to estimate instantaneous left ventricular pressure. Estimated left ventricular pressure waveforms reproduced measured left ventricular pressure closely. The mean error at peak left ventricular pressure was 0.2 +/- 4.8 mm Hg (r = 0.98, p = 0.001). The average error throughout ejection was 0.9 +/- 5.1 mm Hg. The error of estimated pressure was not related to age or the severity of aortic stenosis. The Doppler peak instantaneous gradient was observed to correlate closely (r = 0.97, p = 0.001) with peak to peak gradient. With this technique, the left ventricular pressure waveform throughout ejection can be accurately estimated noninvasively in patients with aortic stenosis. This methodology enables determination of mean, total and instantaneous systolic left ventricular pressure.     

Echocardiographic left ventricular wall thickness: a poor predictor of the severity of aortic valve stenosis

Echocardiographic left ventricular hypertrophy is thought to be helpful in grading the severity of aortic stenosis. This study compared M-mode echocardiographic left ventricular wall dimensions with Gorlin aortic valve area. Good quality echocardiograms were obtained in 294 patients with aortic stenosis who also underwent cardiac catheterization. Patients with grade 3 or 4 aortic regurgitation were excluded. The correlation was calculated between the aortic valve area and the left ventricular wall dimensions. Correlation coefficients were poor; r = 0.13 for the septum, r = 0.15 for the posterior wall, and r = 0.17 for the mean wall dimension. Correlation was not improved significantly if patients with poor left ventricular function or systemic hypertension were excluded. Correlation with other hemodynamic parameters was better, peak left ventricular systolic pressure having r values of 0.36 and 0.30 for posterior wall and septum. Mean and peak aortic valve gradient had r values approaching 0.30 for both dimensions. If the peak gradient was included in multivariate analysis, the wall dimensions then had no predictive power for severity of aortic stenosis. This study demonstrates that the degree of left ventricular wall hypertrophy is not related to the severity of aortic outflow obstruction and therefore cannot be used to grade the severity of aortic stenosis.     

Minimally invasive transaortic mitral valve repair during aortic valve replacement

Herein, we report the case of a 77-year-old man who presented with congestive heart failure. Echocardiography and cardiac catheterization revealed severe aortic stenosis with severe mitral regurgitation and a left ventricular ejection fraction of 0.20. Because of comorbidities, the patient was considered to be at high risk for double-valve surgery. In order to reduce the operative risk, a minimally invasive aortic valve replacement was performed together with a transaortic edge-to-edge repair (Alfieri stitch) of the mitral valve. We discuss the surgical technique and note the positive outcome. To our knowledge, this is the 1st report of minimally invasive aortic valve replacement and transaortic mitral valve repair with use of the Alfieri stitch.     

Experimental validation of Doppler echocardiographic measurement of volume flow through the stenotic aortic valve

In aortic stenosis, evaluation of aortic valve area by the continuity equation assumes that the volume of flow through the stenotic valve can be measured accurately in the left ventricular outflow tract. To test the accuracy of Doppler volume-flow measurement proximal to a stenotic valve, we developed an open-chest canine model in which the native leaflets were sutured together to create variable degrees of acute aortic stenosis. Left ventricular and aortic pressures were measured with micromanometer-tipped catheters. Volume flow was controlled and varied by directing systemic venous return through a calibrated roller pump and back to the right atrium. Because transaortic volume flow will not equal roller pump output when there is coexisting aortic insufficiency (present in 67% of studies), transaortic flow was measured by electromagnetic flowmeter with the flow probe placed around the proximal descending thoracic aorta, just beyond the ligated arch vessels. In 12 adult, mongrel dogs (mean weight, 25 kg), the mean transaortic pressure gradient ranged from 2 to 74 mm Hg, and transaortic volume flow ranged from 0.9 to 3.2 l/min. In four dogs, electromagnetic flow that was measured distal to the valve was accurate compared with volume flow determined by timed collection of total aortic flow into a graduated cylinder (n = 24, r = 0.97, electromagnetic flow = 0.87 Direct +0.13 l/min). In eight subsequent dogs, electromagnetic flow was compared with transaortic cardiac output measured by Doppler echocardiography in the left ventricular outflow tract as circular cross-sectional area [pi(D/2)2] x left ventricular outflow tract velocity-time integral x heart rate.(ABSTRACT TRUNCATED AT 250 WORDS)     

Relation between hemodynamics and ventricular arrhythmia in patients with heart valve diseases

The incidence and severity of ventricular arrhythmias were compared with hemodynamic findings of cardiac catheterization, in 160 patients with mitral and aortic valve disease. All patients underwent right and left heart catheterization, as well as M-mode and 2D-echocardiography, and 24-hour ambulatory electrocardiographic monitoring. Out of 160 patients, 68 had mitral valve disease and 92 had aortic valve disease. In mitral regurgitation the degree and frequency of ventricular arrhythmias showed a positive correlation to the degree of regurgitation (rs = 0.44, rs = 0.56, respectively) and a negative correlation to left ventricular ejection fraction (rs = -0.49, rs = -0.57) and to cardiac index (rs = 0.48, rs = 0.53). In aortic valve disease the incidence and severity of ventricular arrhythmias were not related to the type of valve lesion, to the transvalvular pressure gradient nor to the degree of regurgitation. In aortic stenosis, the degree of arrhythmia showed a negative correlation to left ventricular ejection fraction (rs = 0.55) and a positive correlation to left ventricular endsystolic volume index (rs = 0.40) and to peak systolic left ventricular wall stress (rs = 0.59). In aortic regurgitation the number of ventricular arrhythmias showed a negative correlation to left ventricular ejection fraction (rs = -0.43) and a positive correlation to left ventricular endsystolic volume index (rs = 0.43) and to peak systolic left ventricular wall stress (rs = 0.37). These data demonstrate that the incidence and severity of ventricular arrhythmias, in patients with aortic valve disease and mitral regurgitation, are strongly associated with the impairment of left ventricular function.     

Ventricular arrhythmias in patients with aortic valve disease (author's transl)

In order to investigate the incidence of severe ventricular arrhythmias, the 24-h ambulatory ECG of 55 patients with aortic valve disease (NYHA classes I-IV; stenosis: n = 24; regurgitation: n = 18; mixed lesions: n = 13) without coronary heart disease were evaluated with regard to the number of premature ventricular beats and according to the Lown classification. Ventricular arrhythmias were found in 73% of all patients (Lown classes III-V: 38%; Lown classes IV-V: 20%). A significant relation between the degree of arrhythmias and the gradient or severity of regurgitation of the aortic valve could not be established. However, there was a significant linear correlation between the left ventricular ejection fraction and the degree of arrhythmias (stenosis: r = 0.60; regurgitation: r = -0.72; mixed lesions: r = 0.78; all p less than 0.005). Complex arrhythmias of Lown classes III-IV are rare (less than 10%) in patients with good left ventricular function (LVEF greater than 60%). There was a history of palpitations in 81% of patients with Lown classes III-V. According to these data, ventricular arrhythmias are present in a large number of patients with aortic valve disease. The degree of arrhythmia does not correlate to the transvalvular stenosis or the severity of regurgitation, but is strongly influenced by the myocardial performance. Therefore in patients with aortic valve disease significant arrhythmias are frequently a sign of impaired LV function.     

Valvular aortic stenosis: disease severity and timing of intervention

Standard echocardiographic evaluation of aortic stenosis (AS) severity includes measurement of aortic velocity, mean transaortic pressure gradient, and continuity equation valve area. Although these measures are adequate for decision making in most patients, there is no single value that defines severe stenosis. Aortic stenosis affects not just the valve, but the entire vascular system, including the left ventricle (LV) and systemic vasculature. More sophisticated measures of disease severity might explain the apparent overlap in hemodynamic severity between symptomatic and asymptomatic patients and might better predict the optimal timing of valve replacement. There have been several approaches to evaluation of stenosis severity based on valve hemodynamics, the ventricular response to increased afterload, ventricular-vascular coupling, or the systemic functional consequences of valve obstruction, such as exercise testing and serum brain natriuretic peptide levels. Aortic valve replacement is indicated when symptoms due to severe AS are present. In most asymptomatic patients, the risk of surgery is greater than the risk of watchful waiting so that management includes patient education, periodic echocardiography, and cardiac risk factor modification. Many adults with AS have comorbid conditions that affect both the diagnosis and management of the valve disease, including aortic regurgitation, aortic root dilation, hypertension, coronary artery disease, LV dysfunction, and atrial fibrillation. Comorbid conditions should be evaluated and treated based on established guidelines, although awareness of the potential effects of therapy in the presence of valve obstruction is needed.     

Valvular aortic stenosis: disease severity and timing of intervention.

Standard echocardiographic evaluation of aortic stenosis (AS) severity includes measurement of aortic velocity, mean transaortic pressure gradient, and continuity equation valve area. Although these measures are adequate for decision making in most patients, there is no single value that defines severe stenosis. Aortic stenosis affects not just the valve, but the entire vascular system, including the left ventricle (LV) and systemic vasculature. More sophisticated measures of disease severity might explain the apparent overlap in hemodynamic severity between symptomatic and asymptomatic patients and might better predict the optimal timing of valve replacement. There have been several approaches to evaluation of stenosis severity based on valve hemodynamics, the ventricular response to increased afterload, ventricular-vascular coupling, or the systemic functional consequences of valve obstruction, such as exercise testing and serum brain natriuretic peptide levels. Aortic valve replacement is indicated when symptoms due to severe AS are present. In most asymptomatic patients, the risk of surgery is greater than the risk of watchful waiting so that management includes patient education, periodic echocardiography, and cardiac risk factor modification. Many adults with AS have comorbid conditions that affect both the diagnosis and management of the valve disease, including aortic regurgitation, aortic root dilation, hypertension, coronary artery disease, LV dysfunction, and atrial fibrillation. Comorbid conditions should be evaluated and treated based on established guidelines, although awareness of the potential effects of therapy in the presence of valve obstruction is needed.     

Aortenstenose

Aortic valve stenosis is the most frequent reason for prosthetic valve replacement in adults. Its incidence increases with age. Development of the most frequent form, degenerative-calcific aortic stenosis, is related to atherosclerotic risk factors. The narrowing of the aortic valve orifice leads to creation of a systolic pressure drop, the gradient, between left ventricle and ascending aorta. The pressure overload from aortic stenosis causes concentric left ventricular hypertrophy and later heart failure. Typical symptoms of severe aortic stenosis include dyspnea, angina, and dizziness or syncope. On auscultation, a loud systolic murmur over the base of the heart is apparent, which is transmitted to the carotids. The ECG often shows left ventricular hypertrophy. The most important diagnostic technique is echocardiography, which allows to measure the gradient and to calculate the orifice area, which determine the degree of severity. The development of symptoms or impaired left ventricular function in severe aortic stenosis should prompt surgical treatment by valve replacement. Truly asymptomatic patients with preserved left ventricular function should be followed conservatively.     

Diagnose und Therapie der Aortenklappenstenose

Aortic valve stenosis (AS) is the most frequently observed valvular heart disease. Once it is symptomatic the mortality rapidly increases. The diagnostic gold standard is transthoracic echocardiography. By measuring the maximum transvalvular velocity, mean transaortic pressure gradient and aortic valve opening area, classification of the type of stenosis can be defined. A differentiation is made between high-gradient AS, low-flow low gradient AS with reduced ventricular ejection fraction (<50%) and the paradoxical low-flow low-gradient AS with preserved ventricular function (≥50%). In some cases, additional diagnostic tools are necessary using dobutamine stress echocardiography, transesophageal echocardiography and cardiac computed tomography. The treatment follows an individualized approach. In cases of indications for valve replacement the multidisciplinary heart team takes into account the patient’s age and individual risk for deciding whether an open surgical approach or transcatheter aortic valve implantation is indicated.     

Effects of increasing flow rate on aortic stenotic indices: evidence from percutaneous transvenous balloon dilatation of the mitral valve in patients with combined aortic and mitral stenosis.

OBJECTIVES: To investigate the effects of transvalvar flow rate on aortic valve resistance and valve area after percutaneous transvenous balloon dilatation of the mitral valve in a homogeneous group of patients with rheumatic heart disease. DESIGN: Retrospective analysis of 12 patients with combined aortic and mitral stenosis who had undergone balloon dilatation of the mitral valve over a period of 9 years. SETTING: Tertiary referral centre. PATIENTS: Twelve (8 women, 4 men; mean (SD) age 37 (9) of 227 consecutive patients with critical mitral stenosis undergoing transvenous balloon dilation of the mitral valve in the centre also had aortic stenosis, defined as a transaortic pressure gradient of more than 25 mm Hg measured at a catheterisation study before valvuloplasty. INTERVENTIONS: Echocardiographic variables (mitral valve area measured by the pressure half-time method and planimetry, and the aortic valve area derived from the continuity equation) and haemodynamic measurements (cardiac output, left ventricular mean systolic pressure, aortic mean pressure, transaortic valve pressure gradient, mitral valve and aortic valve areas derived from the Gorlin formula, and aortic valve resistance) were assessed before and after transvenous balloon dilatation of the mitral valve. Follow up catheterisation to measure haemodynamic variables was performed one week after mitral valvuloplasty. RESULTS: Mean transaortic flow rate increased 33% after mitral valvuloplasty (from 198 (68) to 254 (41) ml/s, P = 0.002). Aortic valve areas derived from the Gorlin formula were significantly increased from 0.57 (0.12) to 0.73 (0.14) cm2 (P = 0.006) after mitral valvuloplasty. However, aortic valve area and valve resistance derived from the continuity equation were independent of the increase in flow rate after mitral valvuloplasty (from 1.29 (0.35) to 1.30 (0.29) cm2 and from 317 (65) to 259 (75) dyn.s.cm-5, both P = NS). CONCLUSION: The Gorlin-derived aortic valve area tends to be flow-dependent, and continuity equation-derived aortic valve area and catheterisation-derived valve resistance seem to be less flow-dependent. In patients with combined mitral and aortic stenosis, these flow-independent indices are important for decision-making.     

Aortic valve stenosis

Aortic valve stenosis is the most frequent reason for prosthetic valve replacement in adults. Its incidence increases with age. Development of the most frequent form, degenerative-calcific aortic stenosis, is related to atherosclerotic risk factors. The narrowing of the aortic valve orifice leads to creation of a systolic pressure drop, the gradient, between left ventricle and ascending aorta. The pressure overload from aortic stenosis causes concentric left ventricular hypertrophy and later heart failure. Typical symptoms of severe aortic stenosis include dyspnea, angina, and dizziness or syncope. On auscultation, a loud systolic murmur over the base of the heart is apparent, which is transmitted to the carotids. The ECG often shows left ventricular hypertrophy. The most important diagnostic technique is echocardiography, which allows to measure the gradient and to calculate the orifice area, which determine the degree of severity. The development of symptoms or impaired left ventricular function in severe aortic stenosis should prompt surgical treatment by valve replacement. Truly asymptomatic patients with preserved left ventricular function should be followed conservatively.     

Sinnvolle Diagnostik und Therapieplanung bei organischer und relativer Mitralklappeninsuffizienz

While morphologic alteration of parts of the mitral valve apparatus (ventricular wall, papillary muscles, chordae tendineae, valve annulus and leaflets) may result in a loss of its functional integrity (primary mitral regurgitation, MR) mitral annulus dilatation following left ventricular enlargement or change in chamber geometry and consecutive opening of the angle between papillary muscles and valve annulus cause secondary MR. Irrespective of these etiologies MR is chronically progressive and much more than the severity of MR the grade of myocardial adaptation to the chronic volume overload is of prognostic significance. Inadequate myocardial adaptation is demonstrated by an increase of the echocardiographically determined radius (r) to wall thickness (Th) ratio (r/Th > 3.0), indicating increasing left ventricular wall stress or by an insufficient increase of the left ventricular ejection fraction (<5% of resting values) under exercise conditions, e. g. with radionuclid angiocardiography (RNV). Stressecho may replace RNV in the future for this indication. Actually, stress echo is not reliable to determine changes in left ventricular ejection fraction at rest versus exercise because of systematic errors and error reproduction. There are preliminary reports on biochemical markers like noradrenalin or tumor necrosis factor alpha being helpful to determine the breakdown of myocardial adaptation mechanisms. Surgical intervention is indicated in chronic MR irrespective of the hemodynamic severity, if myocardial adaptation is inadequate. If mitral reconstruction, the surgical technique of choice, remains insufficient to restore normal valve function, mitral valve replacement with preservation of the subvalvular apparatus is unavoidable. For a deceleration of the progressive volume overload in chronic MR for which a surgical intervention is not yet indicated, a long-term afterload reducting medical therapy preferably with long acting ACE-inhibitors seem to be prognostically favorable.