Left atrial dimension and risk of systemic embolism in patients with a prosthetic heart valve. Department of Veterans Affairs Cooperative Study on Valvular Heart Disease

The relation between left atrial dimension measured by M-mode echocardiography and systemic embolization after valve replacement was examined prospectively among 397 patients with a prosthetic valve enrolled in the Department of Veterans Affairs Cooperative Study on Valvular Heart Disease. Baseline characteristics including several measures of left atrial enlargement were compared for 31 patients who developed systemic embolism and 366 who did not develop embolism during a 5 year follow-up period. Variables that were significantly related to left atrial dimension or systemic embolization in univariate analyses were included with several others in a multiple logistic regression model. The incidence rate of systemic embolism was more than three times higher after mitral valve replacement than after aortic valve replacement (4.4 and 1.3 per 100 patient-years, respectively); this difference persisted after adjustment for other factors. Univariate analysis indicated a threefold higher incidence of systemic embolism in patients with a left atrial dimension greater than or equal to 4 cm compared with that in patients with a dimension less than 4 cm (3 versus 1 per 100 patient-years, respectively). However, when the effect of valve location (mitral versus aortic) was taken into account using either univariate or multivariate techniques, left atrial dimension was found not to be associated with systemic embolism. In multivariate analysis, atrial fibrillation, age, ejection fraction and location of the prosthetic valve were significantly associated with embolism. Results of this multicenter study suggest that left atrial dimension is not independently related to the development of systemic embolism in patients undergoing valve replacement.     

Determinants of subsequent late postoperative left ventricular function and reversal of ventricular dilatation after mitral valve replacement for chronic mitral regurgitation.

We studied 16 patients with chronic mitral regurgitation by echocardiography before, and at 3 weeks, at 6-8 months and at 1-9 years after mitral valve replacement (MVR) to investigate serial changes in left ventricular (LV) function and reversal of ventricular dilatation. All patients at an average of 2.6 years after, and 8 patients before MVR were also studied by echocardiography and, except for 3 patients by measuring plasma catecholamines from the right atrium during bicycle exercise. Before operation, all patients were divided into group A (n = 12) with end-systolic dimension (ESD) < 4 cm and systolic blood pressure (SBP)/ESD > 3, and group B (n = 4) with ESD > 4 cm and SBP/ESD < 3. Maximum reduction in end-diastolic dimension (EDD) occurred at 3 weeks in all patients after MVR (from 60.5 +/- 3.7 to 49.0 +/- 4.5 mm, p < 0.05). ESD was reduced significantly (p < 0.5) only in group A. LV function was normal in group A, but it was depressed in group B at early and late periods after MVR. The slopes of the relationship between the mean velocity of circumferential fiber shortening (Vcf) and plasma norepinephrine (NE) during exercise in all patients in group B decreased along with the depression in LV function. After operation, all patients in group A reached New York Heart Association (NYHA) functional class I, while patients in group B were in NYHA class II. It is concluded that the surgical outcome after MVR for chronic MR will be better if preoperative ESD < 4 cm and SBP/ESD > 3. The relationship between mean Vcf and plasma NE during exercise seemed to be a useful index to evaluate the inotropic reserve of the LV.     

Fibrin sealant for left ventricular rupture after mitral valve replacement

Despite safer surgical procedures, left ventricular rupture remains a rare but potentially lethal complication of mitral valve replacement. The use of fibrin sealant has substantially improved the outcome of many difficult bleeding episodes after cardiac surgery. We describe a case of left ventricular rupture successfully treated with fibrin sealant combined with external Teflon-pledgeted sutures.     

Determinants of survival after aortic valve replacement.

The aim of this study to was evaluate the surgical results of Aortic Valve Replacement (AVR) and to identify the predictive variables associated to risk. A total of 650 consecutive patients underwent isolated AVR at the Thoracic Surgery Centre, S. Jo?o Hospital, Oporto, between January 1976 and December 1996. There were 29 (4.5%) early operative deaths and 108 follow-up deaths (64 cardiac and 44 non cardiac), which represents a linearized rate of 2.3% patients per year. The 5, 10 and 15 year cumulative survival rates for the 650 patients were 85 +/- 3%; 76 +/- 4.1% and 64 +/- 6.6, respectively. According to data in the literature, six preoperative variable and four operative variables were selected to be tested for association to risk. Multivariate analysis identified advanced age and the year of operation as the most important predictors of mortality followed by the type of the prosthesis (the mechanical valves performing better than the biological ones) and the prosthetic valve size (the small prosthesis performing worse than the others). We concluded that AVR is currently a low risk procedure at our Centre. The patient's age emerges as the main risk factor for overall mortality; a mechanical prosthesis should be preferred, at least before the age of 60, and prostheses with a ring size below 21-mm should be avoided.     

Effect of mitral valve replacement on left ventricular function in mitral regurgitation.

To evaluate the effect of mitral valve replacement on left ventricular function in mitral regurgitation, we measured (1) the end-systolic stress/volume ratio, which is practically independent of changes in loading conditions, and (2) the left ventricular contractile reserves upon isometric exercise, both before and one year after mitral valve replacement in 11 patients with mitral regurgitation. The end-systolic stress/volume ratio increased, though the ejection fraction decreased after mitral valve replacement. The ejection fraction decreased and the end-systolic stress/volume ratio remained unchanged during isometric exercise before operation, whereas afterwards the ejection fraction remained unchanged and the end-systolic stress/volume ratio increased during exercise. Ventricular function improves after mitral valve replacement in patients with mitral regurgitation, though the ejection fraction, which is affected by altered loading conditions, deteriorates. The left ventricular response to stress caused by isometric exercise is also improved after surgery.     

Successful repair of late left ventricular rupture after mitral valve replacement

Ventricular rupture is a dreaded complication of mitral valve replacement. Herein are reported two cases of late left ventricular rupture following mitral valve replacement at 10 and 48 days, respectively, after the initial surgery. Both ventricular ruptures were successfully repaired, one through an internal and one an external approach.     

Echocardiographic findings and clinical features of left ventricular pseudoaneurysm after mitral valve replacement.

We studied the echocardiographic findings and clinical features of left ventricular pseudoaneurysm after mitral valve replacement. From December 1979 to March 1991, 1050 patients underwent mitral valve replacement at our institute, and eight patients (0.8%) had left ventricular pseudoaneurysm. In all eight patients, left ventricular pseudoaneurysm developed after the second mitral valve replacement. The incidence of left ventricular pseudoaneurysm among 253 patients who had had previous mitral valve surgery was 3.1%. Seven of the eight patients were still alive and were followed up from 5 to 136 months (mean, 57 months) after the development of left ventricular pseudoaneurysm; these patients had no complications. One patient died as a result of low cardiac output after mitral valve replacement in spite of repair of the left ventricular pseudoaneurysm. This patient had a long and wide myocardial laceration near the left ventricular pseudoaneurysm. In the other seven patients, transthoracic echocardiography demonstrated a large extraventricular cavity along the posterobasal left ventricle. In five of these patients, a turbulent flow in the neck of the left ventricular pseudoaneurysm was recorded both in systole and diastole by pulsed and color Doppler echocardiography. Transesophageal echocardiography clearly showed the narrow neck of the left ventricular pseudoaneurysm and an abnormal flow between the left ventricle and the left ventricular pseudoaneurysm. Generally, when left ventricular pseudoaneurysm develops after mitral valve replacement, surgical repair is the first choice of therapy. Our study demonstrated, however, that the development of left ventricular pseudoaneurysm was not always associated with a poor prognosis without surgical intervention.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of mitral valve replacement on left ventricular function in mitral regurgitation

To evaluate the effect of mitral valve replacement on left ventricular function in mitral regurgitation, we measured (1) the end-systolic stress/volume ratio, which is practically independent of changes in loading conditions, and (2) the left ventricular contractile reserves upon isometric exercise, both before and one year after mitral valve replacement in 11 patients with mitral regurgitation. The end-systolic stress/volume ratio increased, though the ejection fraction decreased after mitral valve replacement. The ejection fraction decreased and the end-systolic stress/volume ratio remained unchanged during isometric exercise before operation, whereas afterwards the ejection fraction remained unchanged and the end-systolic stress/volume ratio increased during exercise. Ventricular function improves after mitral valve replacement in patients with mitral regurgitation, though the ejection fraction, which is affected by altered loading conditions, deteriorates. The left ventricular response to stress caused by isometric exercise is also improved after surgery.     

Asymptomatic left ventricular outflow tract obstruction after mitral valve replacement with leaflet preservation.

It has been shown that inappropriate anterior mitral leaflet preservation during mitral valve replacement may cause left ventricular outflow tract (LVOT) obstruction, usually with dismal prognosis. In this report, we describe a patient with chronic asymptomatic LVOT obstruction after mitral valve replacement with leaflet preservation.     

Subvalvular left ventricular pseudoaneurysm after mitral valve replacement: two-dimensional echocardiographic findings

Disruption of the posterior mitral anulus is a rare complication of mitral valve replacement that may result in subvalvular left ventricular pseudoaneurysm formation. Such pseudoaneurysm formation was easily recognized by two-dimensional echocardiography in a 54 year old man 3 years after his second mitral valve replacement. The finding was confirmed by cineangiography and direct surgical inspection. Recognition of this rare complication of mitral valve replacement has therapeutic importance because surgical correction is necessary.     

Rupture of a ventricular abscess after mitral valve replacement.

A 65 year old man presented with bacterial endocarditis of the mitral valve. Immediately after mitral valve replacement a valve ring abscess ruptured. Early surgery should be performed when an intramyocardial abscess is suspected.     

Rupture of a ventricular abscess after mitral valve replacement.

A 65 year old man presented with bacterial endocarditis of the mitral valve. Immediately after mitral valve replacement a valve ring abscess ruptured. Early surgery should be performed when an intramyocardial abscess is suspected.     

Starting aspirin therapy after operation. Effects on early graft patency. Department of Veterans Affairs Cooperative Study Group.

BACKGROUND. Although aspirin therapy started before operation improves vein graft patency after coronary artery bypass grafting, it also causes bleeding. The objective of this prospective, centrally directed, randomized, double-blind, placebo-controlled trial was to compare the effects of aspirin therapy started before operation with aspirin started 6 hours after operation on early (7-10-day) graft patency. METHODS AND RESULTS. Patients were randomized to receive either aspirin 325 mg or placebo the night before surgery; after operation, all patients received aspirin 325 mg daily, with the first dose administered through the nasogastric tube 6 hours after operation. Angiography was performed in 72% of the analyzed patients an average of 8 days after operation, and the primary end point was saphenous vein graft patency in 351 patients. Internal mammary artery graft patency was also assessed in 246 patients because many individuals received both internal mammary artery and vein grafts. In the patients given preoperative aspirin, the vein graft occlusion rate was 7.4 +/- 1.3% compared with 7.8 +/- 1.5% in those who received preoperative placebo (p = 0.871). In the subgroup of patients receiving Y grafts, 0.0% of the grafts were occluded in the preoperative aspirin group compared with 7.0 +/- 3.6% in the preoperative placebo group (p = 0.066). The internal mammary artery occlusion rate was 0.0% (0 of 131) in the aspirin group compared with 2.4 +/- 1.4% (three of 125) in the placebo group (p = 0.081). Patients in the aspirin group received more transfusions than those in the placebo group (median, 900 versus 725 ml, p = 0.006). The reoperation rate for bleeding in the aspirin group was 6.3% compared with 2.4% in the placebo group (p = 0.036). Median chest tube drainage within the first 6 hours after operation was 500 ml in the aspirin group compared with 448 ml in the placebo group (p = 0.011). CONCLUSIONS. Thus, preoperative aspirin is associated with increased bleeding complications and offers no additional benefit in early vein graft patency compared with starting aspirin therapy 6 hours after operation. There was a trend, although not significant, toward improved early patency for Y grafts and internal mammary artery grafts with preoperative aspirin.     

Left ventricular pseudoaneurysm after replacement of the mitral valve: long-term survival and spontaneous closure

Left ventricular pseudoaneurysms, with or without overt ventricular rupture, are usually fatal in the absence of prompt surgical intervention. This report details the long-term survival of a patient who developed a left ventricular pseudoaneurysm following repair of ventricular rupture subsequent to replacement of the mitral valve, with spontaneous closure of the "neck" of the pseudoaneurysm.     

Echocardiographic assessment of left ventricular filling after mitral valve surgery.

In order to investigate the functional effects of mitral valve surgery, echocardiograms showing left ventricular dimension were recorded and digitised in 14 normal subjects and 129 patients after mitral valve surgery. Measurements were made of peak rate of increase of dimension (dD/dt) and duration of rapid filling, studies on left ventriculograms in 36 patients having shown close correlation between these values and changes in cavity volume. In 14 patients with mitral stenosis, peak dD/dt was reduced to 7-2 +/ 1-5 cm/s, and filling period prolonged to 330 +/- 65 ms, compared with normal (16-0 +/- 3-2 cm/s, and 160 +/- 50 ms, respectively), and after mitral valvotomy, these values improved significantly (10-4 +/- 2-7 cm/s and 245 +/- 55 ms). Characteristic abnormalities were found in 67 patients with mitral prostheses. Values for the Björk-Shiley (10-5 +/- 4-2 cm/s and 180 +/- 80 ms) and Hancock (10-3 +/- 3-7 cm/s, 245 +/- 80 ms) values were similar, and both superior to the Starr-Edwards (7-4 +/- 3-0 cm/s, 295 +/- 105 ms). Results after mitral valve repair in 30 cases were not significantly different from normal (14-4 +/- 5-0 cm/s, 170 +/- 50 ms). Values outside the 95 per cent confidence limits for the valve in question allowed diagnosis of value malfunction in 18 cases. The method is value in comparing different operative procedures and in following up patients after mitral valve surgery.     

二尖瓣置换术中保留后瓣及瓣下结构对左心功能的影响

目的 评价保留二尖瓣后瓣及瓣下结构对二尖瓣瓣膜置换患者左心功能的影响.方法 64例二尖瓣置换患者随机分为两组,保留二尖瓣后瓣及瓣下结构组(MVRP 组)34例,全瓣膜切除瓣膜置换组(MVRC 组)30 例;术前、术后15d和术后3个月分别应用彩色超声多普勒监测MVRP组、MVRC两组左心功能指标.结果 MVRP组左心室舒张末期内径、收缩末期内径、左室功能较MVRC组改善显著(P＜0.05).结论 二尖瓣置换术中保留后瓣及瓣下结构有利于改善瓣膜置换术后左心室功能.