Left ventricular remodeling early after aortic valve replacement: differential effects on diastolic function in aortic valve stenosis and aortic regurgitation

OBJECTIVES: The aim of this study was to evaluate the effect of aortic valve replacement (AVR) on left ventricular (LV) function and LV remodeling, comparing patients with aortic valve stenosis to patients with aortic regurgitation. BACKGROUND: Aortic valve disease is associated with eccentric or concentric LV hypertrophy and changes in LV function. The relationship between LV geometry and LV function and the effect of LV remodeling after AVR on diastolic filling, in patients with aortic valve stenosis compared with aortic regurgitation, are largely unknown.Nineteen patients with aortic valve disease (12 aortic valve stenosis, 7 aortic regurgitation) were studied using magnetic resonance imaging to assess LV geometry and LV function before and 9 +/- 3 months after AVR. Ten age-matched healthy males served as control subjects. RESULTS: Before AVR, the ratio between left ventricular mass index (LVMI) and left ventricular end-diastolic volume index (LVEDVI) was only increased in patients with aortic valve stenosis (1.37 +/- 0.16 g/ml) compared with control subjects (0.93 +/- 0.08 g/ml, p < 0.05). After AVR, LVMI/LVEDVI decreased significantly in aortic valve stenosis (to 1.15 +/- 0.14 g/ml, p < 0.0001), but increased significantly in aortic regurgitation (1.02 +/- 0.20 g/ml to 1.44 +/- 0.27 g/ml, p < 0.0001). Before AVR, diastolic filling was impaired in both aortic valve stenosis and aortic regurgitation. Early after AVR, diastolic filling improved in patients with aortic valve stenosis, whereas patients with aortic regurgitation showed a deterioration in diastolic filling. CONCLUSIONS: Early after AVR, patients with aortic valve stenosis show a decrease in both LVMI and LVMI/LVEDVI and an improvement in diastolic filling, whereas in patients with aortic regurgitation, LVMI decreases less rapidly than LVEDVI, causing concentric remodeling of the LV, most likely explaining the observed deterioration of diastolic filling in these patients.     

心室功能对主动脉瓣关闭不全外科治疗效果的影响

目的 分析主动脉瓣关闭不伞合并不同程度左心室功能障碍患者的临床资料,探讨左心室功能对此类患者外科手术风险及早期疗效的影响.方法 回顾性分析2001年1月至2008年12月144例主动脉瓣关闭不全患者的临床资料,按左心室射血分数(LVEF)将其分为3组(LVEF<35%组,LVEF35%～45%组和LVEF45%～55%...     

Left ventricular remodeling after aortic valve replacement]

The aim of the study was the assessment of left ventricular (LV) systolic function and left ventricular mass following aortic valve replacement (AVR) due to aortic valve stenosis as well as the influence of regression of LV hypertrophy in patients with normal and impaired LV systolic function prior to surgery. 74 patients with severe aortic valve stenosis (29 female, 45 male, mean age 66 +/- 18 years) were divided into 2 groups according to LV ejection fraction (EF): Group 1 with EF > 50% (n = 40); Group 2 with EF < or = 50% (n = 34). Furthermore, patients were differentiated into a group A without (n = 53) and a group B with aortic regurgitation (< or = II degrees, n = 21). All patients were examined by transthoracic echocardiography before and 1 month after surgery. There was a significant decrease of LV enddiastolic and endsystolic volume indices following AVR in group 2 and group B. Patients with preoperatively lower EF (group 2) showed an increase in LV ejection fraction from 39 +/- 10% before AVR to 47 +/- 11% after AVR (p < 0.001), whereas patients with preoperative normal EF (group 1) showed a significant decrease in EF (from 62 +/- 8% to 57 +/- 10%, p < 0.05). Also patients with combined aortic valve disease before AVR had an increase of EF after surgery (from 45 +/- 14% to 56 +/- 14%, p < 0.03). There were significant decreases of interventricular septum thickness and LV posterior wall thickness in group 1 and group A, whereas a significant decrease of LV enddiastolic diameter index was noted only in group B. Improvement of the NYHA functional class could be demonstrated in group 2 from 2.8 +/- 0.7 before to 2.2 +/- 0.6 after AVR, as well as in group B from 2.9 +/- 0.7 before to 1.9 +/- 0.7 after surgery. In conclusion, patients with impaired LV function or combined aortic valve disease showed a significant improvement of left ventricular systolic function after AVR, while patients with normal LV function presented a slight decrease of EF. There was a significant regression of left ventricular muscle mass in all groups independent of the left ventricular functional status.     

The effect of aortic valve replacement on N-terminal natriuretic propeptides in patients with aortic stenosis

BACKGROUND: Increased plasma concentrations of natriuretic peptides have been demonstrated to be associated with increased intracardiac pressure and left ventricular (LV) hypertrophy. After aortic valve replacement (AVR) in aortic stenosis patients, there is a relief of the left outflow obstruction with a substantial hemodynamic improvement. This is followed by a gradual regression of the LV hypertrophy. HYPOTHESIS: After AVR, reduction in LV filling pressure is expected to occur rapidly, while regression of LV hypertrophy will take place over a longer time period. On this basis we hypothesized that the plasma levels of N-terminal proatrial natriuretic peptide (NT-proANP) would be reduced early in the postoperative period, while N-terminal probrain natriuretic peptide (NT-proBNP), through its closer reflection of LV hypertrophy, would be sustained for a longer period. METHODS: Two groups of patients with aortic stenosis undergoing AVR were followed for 4 and 12 months, respectively. Plasma concentrations of NT-proANP and NT-proBNP were measured before and after AVR and related to preoperative findings and changes in the aortic valve area index. RESULTS: Before AVR, the patients had significantly increased plasma levels of NT-proANP and NT-proBNP. After AVR, NT- proANP was decreased at 4 and 12 months but remained elevated compared with controls. N-terminal-proBNP tended to decrease, but did not change significantly. When the patients were followed for 12 months, only those with elevated preoperative pulmonary capillary wedge pressure had decreased peptide levels (NT-proANP: p = 0.017, NT-proBNP: p = 0.058). There was no regression of LV hypertrophy. The patients with the largest postoperative valve area index [1.27 (1.10-1.55) cm2/m2] had the largest reduction of NT-proBNP (47%). Those with the smallest valve area index [0.67 (0.54-0.73) cm2/m2] had no decrease in NT-proBNP. CONCLUSIONS: Our study suggests that a reduction in left atrial pressure is the main factor causing the change of NT-proANP level after AVR. A small prosthetic valve orifice area with a high aortic valve gradient might prevent regression of LV hypertrophy, thus representing a stimulus for increased cardiac secretion of NT-proBNP.     

Coronary-subclavian steal associated with severe aortic stenosis treated with combined percutaneous stenting and minimally invasive aortic valve replacement

We describe coronary-subclavian steal restricting flow to the left internal mammary artery (LIMA) associated with critical aortic stenosis treated with combined percutaneous transluminal stenting and minimally invasive aortic valve replacement (AVR). An 86-year-old patient had coronary artery bypass graft placement (CABG) seven years prior with the LIMA anastomosed to the left anterior descending coronary artery (LAD). At the time of CABG, the patient had mild aortic stenosis and normal left ventricular function. By the time of re-presentation with refractory angina and heart failure, the patient had developed critical aortic stenosis. Because repeat CABG with median sternotomy risked damaging the LIMA, pre-operative revascularization was planned to minimize the likelihood of peri-operative ischemia. Stenting of the subclavian artery was performed prior to minimally invasive AVR.     

Valvular aortic stenosis in the elderly

Elderly patients with valvular aortic stenosis have an increased prevalence of coronary risk factors, of coronary artery disease, and evidence of other atherosclerotic vascular diseases. Statins may reduce the progression of aortic stenosis (AS). Angina pectoris, syncope or near syncope, and congestive heart failure are the 3 classic manifestations of severe AS. Prolonged duration and late peaking of an aortic systolic ejection murmur best differentiate severe AS from mild AS on physical examination. Doppler echocardiography is used to diagnose the prevalence and severity of AS. The indications for cardiac catheterization and the medical management of AS are discussed. Once symptoms develop, aortic valve replacement (AVR) should be performed in patients with severe or moderate AS. Other indications for AVR are discussed. Warfarin should be administered indefinitely after AVR in patients with a mechanical aortic valve and in patients with a bioprosthetic aortic valve who have either atrial fibrillation, prior thromboembolism, left ventricular systolic dysfunction, or a hypercoagulable condition. Patients with a bioprosthetic aortic valve without any of these 4 risk factors should be treated with aspirin 75-100 mg daily.     

Coronary steal resulting from LIMA-to-SVG-to-LAD-to-ventricular fistula physiology associated with malpositioned prosthetic aortic valve

Following aortic valve replacement (AVR) and a single vessel bypass (SVG) to the left-anterior descending artery (LAD), the patient had a non-ST segment myocardial infarction with graft occlusion and underwent left internal mammary artery (LIMA) to SVG to LAD. When we evaluated her at our institution for ischemic symptoms, we were able to determine the probable sequence of events and the reason for her symptoms. Her AVR was interfering with normal flow into the left main with associated coronary steal from the distal LAD. The AVR had to be revised and the patient's symptoms improved.     

Survival after aortic valve replacement for severe aortic stenosis with low transvalvular gradients and severe left ventricular dysfunction

OBJECTIVE: We sought to assess whether aortic valve replacement (AVR) among patients with severe aortic stenosis (AS), severe left ventricular (LV) dysfunction and a low transvalvular gradient (TVG) is associated with improved survival. BACKGROUND: The optimal management of patients with severe AS with severe LV dysfunction and a low TVG remains controversial. METHODS: Between 1990 and 1998, we evaluated 68 patients who underwent AVR at our institution (AVR group) and 89 patients who did not undergo AVR (control group), with an aortic valve area < or = 0.75 cm(2), LV ejection fraction < or = 35% and mean gradient < or = 30 mm Hg. Using propensity analysis, survival was compared between a cohort of 39 patients in the AVR group and 56 patients in the control group. RESULTS: Despite well-matched baseline characteristics among propensity-matched patients, the one- and four-year survival rates were markedly improved in patients in the AVR group (82% and 78%), as compared with patients in the control group (41% and 15%; p < 0.0001). By multivariable analysis, the main predictor of improved survival was AVR (adjusted risk ratio 0.19, 95% confidence interval 0.09 to 0.39; p < 0.0001). The only other predictors of mortality were age and the serum creatinine level. CONCLUSIONS: Among select patients with severe AS, severe LV dysfunction and a low TVG, AVR was associated with significantly improved survival.     

The Effect of Aortic Valve Replacement on Coronary Flow Reserve in Patients with a Normal Coronary Angiogram

BACKGROUND: In patients with aortic stenosis and a normal coronary angiogram, a coronary flow reserve (CFR) is impaired. The aim of the present study was to examine the effect of aortic valve replacement (AVR) on the CFR after a long-term follow-up. PATIENTS AND METHODS: 30 patients with aortic stenosis and a normal coronary angiogram were enrolled in the study. CFR measurements were made on 21 patients 123 +/- 137 days before and 497 +/- 167 days after AVR. CFR measurements were carried out according to a standard protocol, with a vasodilator stimulus dipyridamole (0.56 mg/kg for 4 min) and peak diastolic velocity measurements at 6 min. RESULTS: Initially, the average peak gradient of aortic stenosis was 89.5 +/- 22.4 mm Hg. After AVR, it decreased to 26.2 +/- 9 mm Hg. Left ventricular mass was significantly lower after AVR: 354.9 +/- 107.9 g versus 223.8 +/- 73.6 g (p < 0.001). The average baseline diastolic velocity measured by pulsed Doppler in the left anterior descending coronary artery amounted to 62.2 +/- 25.5 cm/s before and 40.1 +/- 13.6 cm/s after AVR. The difference was statistically significant (p < 0.01). The average diastolic velocity at maximum stress equaled 117 +/- 42.8 cm/s pre- and 91.5 +/- 34 cm/s postoperatively (p < 0.005). The calculated CFR before AVR amounted to 1.96 +/- 0.5 and increased to 2.37 +/- 0.8 postoperatively. The difference was statistically significant (p < 0.05). CONCLUSION: Prosthetic AVR is of considerable benefit concerning the CFR in patients with a normal coronary angiogram after a long-term follow-up.     

Aortic valve replacement in childhood: Evaluation of left ventricular function by electrocardiography,echocardiography and graded exercise testing

Preoperative and postoperative left ventricular (LV) performance was evaluated noninvasively in 15 children who survived aortic valve replacement (AVR). The noninvasive evaluation included electrocardiography, M-mode echocardiography, and graded exercise testing. Clinically, there was dramatic improvement postoperatively: All but 2 patients were asymptomatic. No conduction defects or arrhythmias were detected preoperatively; however, in the late postoperative period there was a variety of intraventricular conduction abnormalities, myocardial infarctions, and ventricular or supraventricular arrhythmias. On M-mode echocardiography, children with aortic stenosis continued to have increased LV mass postoperatively. Shortening fraction and left-sided systolic time intervals returned to normal. The children with aortic regurgitation also had persistently abnormal LV mass on echocardiography postoperatively. Exercise data indicated no improvement in working capacity after AVR. Also, 9 children (63%) continued to have ST-segment depression with maximal exercise. These data indicate that AVR does not result in a return to normal of myocardial performance in children with severe aortic valve disease.     

Iatrogenic coronary artery stenosis at the ostium of left anterior descending artery after aortic valve replacement: a case report with imaging and histological findings

Iatrogenic coronary artery stenosis (ICAS) after aortic valve replacement (AVR) is a rare but potentially fatal complication. Immediate traumatic lesions or late stenoses caused by insertion of an antegrade cardioplegia catheter during AVR mostly occur at the site of the left main trunk or right coronary ostium. Here, we report a rare case of ICAS after AVR at the ostium of left anterior descending artery. Intravascular ultrasound provided helpful information to choose and perform directional coronary atherectomy (DCA) as the strategy of percutaneous coronary intervention. Histological examination of the specimen taken by DCA demonstrated intimal hyperplasia and no findings of atheromatous plaque with lipid core or thrombus. The patient has been asymptomatic after the procedure and the follow-up multidetector computed tomography at 1 year showed no restenosis.     

Dobutamine stress echocardiography and left ventricular mass changes of mechanical aortic valve replacement in four years follow-up

AIM: The aim of this study was to investigate the differences in cardiac response to stress according to the size of the prosthetic valve in patients who underwent aortic valve replacement (AVR) and to evaluate the relationship between the size of the prosthetic valve and cardiac recovery-remodeling after the operation. METHODS: Thirty patients who had undergone AVR (12 patients) or double valve replacement (18 patients) underwent dobutamine-stress echocardiography 4.2 years after the operation to evaluate response to stress . They were divided into 2 groups according to valve prosthesis size. The small-size AVR group (group 1, n=17) had prosthetic aortic valves 21 pounds mm; the large-size AVR group (group 2, n=13) had valves >21 mm. Response to stress and preoperative and postoperative echocardiographic findings were compared. Pulsed and continuous-wave Doppler studies were performed at rest and at the end of each stage. Peak and mean aortic gradients, left ventricular diastolic and systolic functions were measured for each group. RESULTS: Dobutamine stress increased heart rate and blood pressure in both groups. Peak pressure gradient across the aortic valve prostheses was 42.1 mm Hg in group 1 and 20.9 mm Hg in group 2 (P<0.05) at rest. After dobutamine infusion, the peak pressure gradient across the aortic valve prostheses increased to 85.1 mm Hg in group 1 and 54 mm Hg in group 2 (P<0.05). Isovolumetric relaxation time returned to normal in both groups following dobutamine infusion; this decrease was significant only in group 1. Patients achieved a decrease in left atrium and left ventricular diameters and volumes, as evidence of remodeling following AVR. Left ventricular mass index (LVMI) decreased from 127.6+/-47.6 to 98.1+/-36.9 and from 159.9+/-16.1 to 125.3+/-10.1 in groups 1 and 2, respectively, but this decline was not statistically significant. CONCLUSIONS: Smaller valves have higher gradients and this significant difference increases under stress. Significant improvement in echocardiographic diameters, cardiac filling volumes and LVMI reflects the benefit of the operation. Cardiac remodeling is independent of valve size, although high transprosthetic gradients occur during stress conditions.     

The evaluation of the left ventricle function in patients with aortic stenosis and severe heart failure after surgical treatment of valvular heart disease

Surgical treatment of aortic stenosis in patients (pts) with severe heart failure represents high-risk procedure. The aim of this study was to identify prognostic factors and assess the late outcome after aortic valve replacement (AVR) in patients with isolated aortic stenosis and left ventricle ejection fraction (EF) < or = 40%. The study group consisted of 37 pts 25 (67%) men and 12 (33%) women, aged 57 +/- 12 yrs. Mean follow-up period was 18 +/- 17 months (range 6 to 72 months). Before AVR and within follow-up period clinical assessment was based on NYHA classes and echocardiographic study to evaluate left ventricle function. Early mortality rate was 8.3%, late mortality was 5.8%. EF significantly improved from 27 +/- 7% to 59 +/- 15% (p < 0.001) after AVR. It was accompanied by clinical improvement. Left ventricle function improvement did not depend on age, sex of patients, concomitant revascularization and preoperative maximum transaortic gradient. Significant correlation (r = -0.4, p = 0.02) between preoperative left ventricle end-diastolic diameter and postoperative EF improvement was noted.     

Aortic valve repair versus replacement in bicuspid aortic valve disease

BACKGROUND AND AIM OF THE STUDY: The study aim was to compare the results of aortic valve repair and replacement with biological valves in adult patients with aortic insufficiency (AI) caused by congenital bicuspid aortic valve (BAV) METHODS: Forty-four patients who had aortic valve repair were matched for age and left ventricular function to 44 patients who had aortic valve replacement (AVR) with biological valves. Patients were followed annually using echocardiography. The mean follow up was 2.6 +/- 2.1 years for the repair group, and 3.5 +/- 2.1 years for the replacement group. Follow up was complete. RESULTS: There was no operative or late death in either group. Early postoperative echocardiography showed trace or no AI in 35 patients and mild AI in nine who had repair, and trace or no AI in 38 patients and mild AI in five who had AVR. The mean peak systolic gradient was 16.2 +/- 7.6 mmHg for repair and 13.2 +/- 7.2 mmHg for AVR. Four patients who had valve repair and two who had AVR, needed repeat aortic valve surgery because of progressive AI or endocarditis. Freedom from reoperation at five years was 91 +/- 5% for repair and 94 +/- 6% for replacement (p = 0.2), while freedom from moderate or severe AI at five years was 79 +/- 8% for repair and 94 +/- 6% for replacement (p = 0.024). The peak systolic gradient at follow up was 11.7 +/- 6.8 mmHg after repair and 13.3 +/- 9.6 mmHg after AVR (p = 0.4). There were no thromboembolic complications in either group. CONCLUSION: Repair of BAV is feasible in certain patients with AI, but the hemodynamics and clinical outcomes do not appear to be superior to AVR with biological valves during the first five years of follow up.     

Myocardial apoptosis predicts postoperative course after aortic valve replacement in patients with severe left ventricular hypertrophy

BACKGROUND AND AIM OF THE STUDY: Myocardial apoptosis has been implicated in heart failure and post-infarct remodeling. In some patients with severe aortic stenosis, delayed valvular replacement is associated with a poor in-hospital outcome. The study aim was to evaluate the impact of cardiomyocyte apoptosis on the postoperative course after aortic valve replacement (AVR) for severe aortic stenosis. METHODS: During elective AVR, myocardial biopsies were obtained from the left ventricle of 11 patients with severe left ventricular hypertrophy (LVH), and the samples analyzed for apoptosis. RESULTS: The mean apoptotic rate was 10.4 +/- 3.7 per thousand. (range: 5-16 per thousand). The apoptotic rate correlated directly with preoperative NYHA functional class, duration of intensive care unit (ICU) stay, number of days of postoperative acute renal insufficiency, and serum level of troponin T at 24 h; the apoptotic rate correlated inversely with cardiac index at 24 h postoperatively. At multivariate analysis, the apoptotic rate and left ventricular mass index were independent predictors of prolonged ICU stay. The apoptotic rate and duration of cardiopulmonary bypass were predictive of the duration of postoperative acute renal insufficiency. CONCLUSION: The study results showed an association between myocardial apoptosis and postoperative outcome in patients with severe LVH submitted for AVR. Non-invasive correlates of apoptosis may be introduced as a means of identifying patients at a higher operative risk, and may help in the evaluation of asymptomatic patients with severe aortic stenosis. Anti-apoptotic strategies before and during surgery would possibly ameliorate the surgical results.     

Echocardiography in chronic aortic insufficiency. Prediction of the reversibility of left ventricular dysfunction following surgical correction

The long term outcome of patients undergoing aortic valve replacement (AVR) for chronic aortic regurgitation (AR) is mainly determined by the reversibility or permanence of left ventricular dysfunction. We analysed the echocardiogram of 49 patients before and after surgery to identify the patients whose left ventricular dysfunction regressed completely after AVR. The patients were divided into 2 groups according to the results of the last postoperative echocardiogram: Group I: 25 patients whose left ventricular dimensions and wall motion reverted to normal; Group II: 24 patients with dilated and/or hypokinetic left ventricles. The two groups of patients were comparable for sex (Group I: 19 men, 6 women; Group II: 20 men, 4 women), age (Group I: 50,8 years, Group II: 53,9 years) and length of postoperative follow-up (Group I: 32 months, Group II: 34 months). The following parameters were measured and compared: diastolic and systolic left ventricular dimensions, myocardial mass and ventricular wall motion. Results: Patients in Group I had less left ventricular dilatation than those in Group II (+35% vs +60%, p less than 0,001) and left ventricular contraction was better (FE: 62% vs 45%, p less than 0,001; %FS: 35% vs 23%, p less than 0,001). This study establishes that patients with chronic AR and % delta Dd less than 60%, an EF greater than 50% or %FS greater than 25%, have about a 90% probability of normalisation of LV function after AVR. If one of the indices exceeds these threshold values, the probability of permanent LV dilatation and/or hypokinesia after AVR is also about 90%.(ABSTRACT TRUNCATED AT 250 WORDS)     

Aortic valve replacement in septuagenarians

To evaluate the risk factors of aortic valve replacement (AVR) in the elderly, 35 patients over the age of 70 who had undergone this procedure were reviewed. Twenty-four patients had isolated AVR, three had double valve replacement, seven had a combined procedure of AVR and aortocoronary bypass, and one had AVR and open mitral commissurotomy. There were 27 elective and eight emergency operations. Nineteen patients were in the New York Heart Association (NYHA) Class III, and 16 patients were in NYHA Class IV preoperatively. Hospital mortality was 7.4% (two cases) in the elective group, and 337.5% (three cases) in the emergency group. The major risk factors were found to be the urgency of operation and left ventricular failure associated with severe pulmonary hypertension. There was no postoperative mortality among the seven patients who underwent the combined procedures of AVR and aortocoronary bypass. Follow-up of survivors revealed that 90% returned to NYHA Class I or II, and have an improved lifestyle. Our data suggest that elective AVR is a safe beneficial operation in septuagenarians. Emergency surgery and severe left ventricular failure contribute to high mortality; therefore, AVR should be performed in septuagenarians as early as indicated.     

Staged Balloon Aortic Valvuloplasty before Standard Aortic Valve Replacement in Selected Patients with Severe Aortic Valve Stenosis

This study evaluated preoperative balloon aortic valvuloplasty (BAV) as a technique to decrease aortic valve replacement (AVR) risk in patients who have severe symptomatic aortic valve stenosis with substantial comorbidity.We report the outcomes of 18 high-risk patients who received BAV within 180 days before AVR from November 1993 through December 2011. Their median age was 78 years (range, 51–93 yr), and there were 11 men (61%). The pre-BAV median calculated Society of Thoracic Surgeons Predicted Risk of Mortality (STS PROM) was 18.3% (range, 9.4%–50.7%). Preoperative left ventricular ejection fraction measured a median of 0.23 (range, 0.05–0.68), and the median aortic valve area index was 0.4 cm²/m² (range, 0.2–0.7 cm²/m²). The median interval from BAV to AVR was 28 days (range, 1–155 d). There were no strokes or deaths after BAV; however, 4 patients (22%) required mechanical circulatory support, 3 (17%) required femoral artery operation, and 1 (6%) developed severe aortic valve regurgitation. After BAV, the median STS PROM fell to 9.1% (range, 2.6%–25.7%) (compared with pre-BAV, P <0.001). Echocardiography before AVR showed that the median left ventricular ejection fraction had improved to 0.35 (range, 0.15–0.66), and the aortic valve area index to 0.5 cm²/m² (range, 0.3–0.7 cm²/m²) (compared with pre-BAV, both P <0.05). All patients received AVR. Operative death occurred in 2 patients (11%), and combined operative death and morbidity in 7 patients (39%).Staged BAV substantially reduces the operative risk associated with AVR in selected patients.     

Reduction of the QT interval dispersion after aortic valve replacement reflects changes in electrical function rather than structural remodeling

BACKGROUND AND AIM OF THE STUDY: Factors related to changes of QT dispersion (QTd) after aortic valve replacement (AVR) in patients with aortic stenosis were analyzed. METHODS: The prospective group comprised 121 consecutive patients (45 women, 76 men; mean age 58 +/- 11 years; range: 24-77 years) with significant aortic valve stenosis. Data (clinical, echocardiographic and electrocardiographic) were collected before and at least 16 months after AVR. QTd was measured in the standard ECG. RESULTS: Before AVR, the mean QTd was 60 +/- 24 ms (QT(max) 424 +/- 40 ms). QTd was > 50 ms in 68% of patients, and > 70 ms in 30%. During postoperative follow up the mean QTd was 54 +/- 19 ms (QT(max) 368 +/- 36 ms) for all patients, and was > 50 ms in 58% of cases and > 70 ms in 13%. Postoperatively, QTd was decreased to < 70 ms in 27% of patients with a normalized left ventricular mass index (LVMI), and in 27% of those without any clinically significant reduction in left ventricular (LV) hypertrophy. In the multivariate analysis, QTd reduction was weakly related to the reduction in LV wall thickness (p = 0.09) and LVMI (p = 0.05). The reduction in QTd was more related to changes in T-wave amplitude in lead V5 (p = 0.004). CONCLUSION: Following AVR for aortic stenosis, a decrease in QTd was observed, notably among patients with QTd > 70 ms. This reduction was only weakly related to the degree of reduction in cardiac hypertrophy, but a more important relationship was observed with changes in T-wave amplitude. These findings suggest that a reduction in QTd after AVR is reflective of changes in electrical function rather than structural remodeling.     

Left ventricular remodeling with intensive exercise after aortic valve replacement

The influence of regular exercise on cardiac remodeling after aortic valve replacement (AVR) is virtually unknown. The case is reported of a 49-year-old male patient who had undergone biological valve replacement for severe aortic regurgitation with reduced left ventricular ejection fraction (LVEF; 45%) and massive left ventricular dilation (left ventricular end-diastolic diameter (LVEDD) 96 mm), which had been recognized for at least three years before surgery. Starting with the normal postoperative cardiac rehabilitation, the patient subsequently intensified his regular endurance training, reaching a total of 9,500 km of cycling within one year. The LVEF (51%) and LVEDD (60 mm) were almost normalized within this period. This was accompanied by an increase in peak VO2, from 27 to 52 ml/min/kg, and in peak exercise capacity (bicycle ergometer) from 75 to 283 W. These findings indicate that even intensive endurance training after AVR seems to be feasible and safe, and may have a beneficial effect on postoperative cardiac remodeling.