Long-term function of human cardiac allografts assessed by two-dimensional echocardiography

Previous studies from our laboratory demonstrated increasing left ventricular mass in cyclosporine-treated cardiac allograft recipients over 30 days after transplantation, but the long-term evolution of this process and possible effects on allograft function are unknown. Accordingly, quantitative two-dimensional echocardiography was performed 2 and 23 days and 15 months postoperatively in 14 recipients treated with cyclosporine and prednisone. Changes in left ventricular ejection fraction, end-diastolic volume, mass, and end-systolic wall stress were analyzed. Comparison of studies at 2 and 23 days revealed significant (p less than 0.01) increases in ejection fraction (54% +/- 8% [standard deviation] to 62% +/- 4%), end-diastolic volume (84% +/- 32 ml to 96 +/- 31 ml), and left ventricular mass (118 +/- 45 gm to 136 +/- 41 gm). Comparison of studies at 23 days and 15 months revealed no significant change in end-diastolic volume or left ventricular mass, whereas ejection fraction decreased slightly (62% +/- 4% to 57% +/- 4%, p less than 0.01). End-systolic wall stress decreased when data at 2 days and 15 months were compared (83 +/- 24 gm/cm2 versus 66 +/- 18 gm/cm2, p less than 0.05), but no change in contractility was apparent from the ejection fraction/end-systolic stress relation. We conclude that left ventricular mass and end-diastolic volume increase early after transplantation in cyclosporine-treated cardiac allograft recipients, but these changes are not predictive of long-term results, which are characterized by no significant late variation in left ventricular mass, end-diastolic volume, or contractility.     

Preoperative and postoperative right ventricular function during exercise in patients with mitral stenosis.

To elucidate the effects of mitral valve surgery on right ventricular function in 11 patients with mitral stenosis, pre- and postoperative right ventricular function were quantified using gated equilibrium blood pool radionuclide ventriculography at rest and during exercise. The preoperative right ventricular ejection fraction was 39 +/- 4% at rest and 36 +/- 9% during exercise, which during exercise was lower than control values (51 +/- 5%) (p < 0.01). When the preoperative right ventricular ejection fraction was lower during exercise than at rest, postoperative right ventricular ejection fraction during exercise was lower than normal values (42 +/- 3% versus 51 +/- 5%) (p < 0.01). When the preoperative right ventricular ejection fraction did not decrease during exercise, the postoperative right ventricular ejection fraction was within normal limits during exercise (54 +/- 5%). In addition, postoperative right ventricular ejection fraction during exercise increased to normal values in patients whose preoperative right ventricular ejection fraction during exercise had been 40% or higher. Preoperative peak ejection rate was -1.81 +/- 0.19 EDV/sec at rest and -1.72 +/- 0.39 EDV/sec during exercise, which during exercise was lower than control values (-2.44 +/- 0.53 EDV/sec) (p < 0.01). Postoperatively, peak ejection rate during exercise (-2.50 +/- 0.37 EDV/sec) increased (p < 0.05) to normal levels. Preoperative peak filling rate was 1.61 +/- 0.47 EDV/sec at rest and 1.88 +/- 0.54 EDV/sec during exercise, which during exercise was lower than control values (2.58 +/- 0.62 EDV/sec) (p < 0.01). Postoperatively, peak filling rate during exercise (2.82 +/- 0.62 EDV/sec) increased (p < 0.05) to normal values in all patients. Preoperative changes in both right ventricular ejection fraction and peak ejection rate from rest to exercise inversely correlated with the preoperative pulmonary vascular resistance at rest (right ventricular ejection fraction, r = -0.79, p < 0.005; and peak ejection rate, r = -0.67, p < 0.05). In conclusion, right ventricular systolic function improved in about half of the patients with mitral stenosis, and diastolic function improved in all patients during exercise following surgery. When the preoperative pulmonary vascular resistance was elevated, the right ventricular systolic dysfunction persisted.     

Assessing exercise performance after heart transplantation

OBJECTIVE: Heart transplantation improves the survival rate and quality of life in patients with severe symptoms of congestive heart failure and an ejection fraction of 20% or less. Despite marked symptomatic and clinical improvement in those who undergo heart transplantation, exercise capacity often remains reduced, and the factors limiting exercise performance during the post-transplantation period remain unclear. This study was performed to investigate the factors affecting exercise capacity in heart transplantation recipients. PATIENTS AND METHODS: Fourteen patients with cardiomyopathy were enrolled in this study. We measured peak exercise oxygen uptake (peak VO(2)) in seven patients (age range: 42 +/- 14 yr) 10-28 months after transplantation, in seven patients (age range: 33 +/- 18 yr) with dilated cardiomyopathy before heart transplantation, and in 14 healthy control subjects (age range: 44 +/- 12 yr). The left ventricular ejection fraction, Beck Depression Inventory score, Medical Outcome Health Survey Short Form-36 Questionnaire (SF-36) results, and immunosuppressive therapy administered were recorded in all patient groups. RESULTS: All patients in the post-transplantation group terminated exercise testing before the anaerobic threshold because of general fatigue. All heart transplantation recipients exhibited a left ventricular ejection fraction within the normal range (mean +/- SD = 57% +/- 2%). The peak VO(2) mean values were significantly different among the three groups (p = 0.001). There were statistically significant correlations between the peak VO(2) values and the Beck Depression Inventory scores (r = -0.637, p = 0.01), between the peak VO(2) values and bodily pain (r = 0.717, p = 0.006), between the peak VO(2) values and general health perceptions (r = 0.706, p = 0.007), and between peak VO(2) values and postoperative duration (r = 0.843, p = 0.03) in all patient groups. CONCLUSION: In the long-term treatment of heart transplant recipients, exercise training should be considered an important therapeutic tool that enables patients to achieve a good quality of life.     

Distribution and declines in cardiac allograft radionuclide left ventricular ejection fractions in relation to late mortality.

BACKGROUND: Cardiac allograft left ventricular ejection fraction (LVEF) is an important measure of left ventricular systolic function. Despite widespread use of LVEF after transplantation, its normal range and prognostic value in cardiac allografts has not been defined. METHODS: We conducted a retrospective cohort study among 292 consecutive adult heart transplant patients. Left ventricular ejection fractions were performed at 1, 3, 12, 24, and 48 months after transplantation using radionuclide ventriculography. Endomyocardial biopsies assessed rejection, right heart catheterization assessed loading conditions, and angiography assessed allograft coronary artery disease. We used Cox proportional hazards model to examine the predictive value of LVEF on late mortality. RESULTS: Of the patients who survived > or =4 years, the mean allograft LVEF decreased 4.7 units at 3 months, from 63.8 to 59.7; an additional 4.1 units at 12 months, from 59.7 to 55.6 (p < 0.001); and remained stable afterward. These changes were not associated with concurrent changes in loading conditions, episodes of rejection, or development of allograft coronary artery disease. Left ventricular ejection fraction lower than the 95% normal limit (<40%) at 12 months was inversely associated with risk for late cardiac mortality (relative risk = 3.5, 95% confidence interval = 1.0-12.2), while controlling for recipient age, sex, donor age, and rejection episodes. CONCLUSIONS: The cardiac-allograft LVEF frequently decreases in the first year after transplantation. The 95th percentile of allograft LVEF value (<40%) at Year 1 predicts late cardiac mortality among transplant recipients.     

Evaluation of predictors of clinical outcome after partial left ventriculectomy

BACKGROUND: Outcome after partial left ventriculectomy (PLV) is difficult to predict. Our goal was to determine if clinical measurements including exercise testing could predict outcome after PLV. METHODS: Sixteen patients with dilated cardiomyopathy had left ventricular ejection fraction, left ventricular end-diastolic diameter, amount of mitral regurgitation (MR), New York Heart Association (NYHA) functional class, and cardiopulmonary exercise testing measurements measured before PLV and 3 months after PLV. Eleven patients who remained stable after PLV (group 1) were compared with 5 patients who deteriorated after PLV (group 2). RESULTS: Similar significant improvements were seen in both groups 3 months post-PLV with respect to left ventricular ejection fraction (group 1: 0.136+/-0.037 to 0.212+/-0.046; group 2: 0.139+/-0.042 to 0.179+/-0.073) and left ventricular end-diastolic diameter (group 1: 8.5+/-0.7 to 7.0+/-0.6 cm; group 2: 7.6+/-0.6 to 6.5+/-0.6 cm). The MR grade (1.0+/-0.6 versus 2.5+/-0.6), NYHA functional class (1.5+/-0.31 versus 2.5+/-0.6), and peak oxygen consumption (17.8+/-1.1 versus 12.2+/-2.0) were significantly different in the two groups 3 months after PLV (p < 0.05, analysis of variance). CONCLUSIONS: Patients that do not show significant improvement in peak oxygen consumption, NYHA class and significant decrease in the amount of MR 3 months after PLV, compared with pre-PLV, are at increased risk of clinically deteriorating.     

Single lung transplantation in rats with chemically induced pulmonary hypertension.

Physiologic effects of single lung transplantation on pulmonary hypertension were studied in rats with monocrotaline-induced pulmonary hypertension. Inbred rats treated with monocrotaline (40 mg/kg) received a left lung isograft from a normal donor 2 weeks later, when pulmonary hypertension became significant (transplant group; n = 6). These rats and control rats treated with monocrotaline (mediated control group; n = 11) or vehicle alone (normal control group; n = 9) were followed up weekly by metabolic treadmill testing for exercise tolerance and oxygen consumption up to 6 weeks after monocrotaline (4 weeks after transplantation), when all rats underwent hemodynamic and histologic examinations. Whereas maximal oxygen consumption and exercise tolerance consistently deteriorated in the medicated control group of rats, indices in the transplant group stopped deteriorating 2 weeks after lung transplantation and remained at levels similar to those of normal control rats. Severe pulmonary hypertension (68 +/- 19 mm Hg) and right ventricular hypertrophy (right ventricular/left ventricular weight ratio, 0.95 +/- 0.19) were confirmed in medicated control rats in contrast to transplant animals, in which these two indices remained at normal control levels. Whereas left-to-right lung perfusion ratio was constant among rats not receiving transplants (0.69 +/- 0.16), it was significantly elevated (2.27 +/- 0.65; p less than 0.001) in those receiving transplants, suggesting preferential flow through the lung isograft. The results suggest that, in the early phase of pulmonary hypertension, single lung transplantation shifts pulmonary perfusion to the grafted lung, avoiding right ventricular pressure overload and thereby preserving exercise tolerance at a nearly normal level in rats with monocrotaline-induced pulmonary hypertension.     

Thermodilution measures of right ventricular ejection fraction and volumes in heart transplant recipients: a comparison with radionuclide angiography.

A reliable, convenient measure of right ventricular ejection fraction may be a useful adjunct to evaluate cardiac allograft rejection. The purpose of this investigation was to compare two measures of right ventricular ejection fraction: (1) radionuclide angiography with the first-pass technique and (2) thermodilution with a balloon flotation catheter. The study was performed in 26 heart transplant recipients; hemodynamics, thermodilution cardiac output, and right ventricular ejection fraction were measured. First pass radionuclide angiography was performed either simultaneously (n = 11) or within 4 hours (n = 15) of the thermodilution study. Mean thermodilution right ventricular ejection fraction was 39% +/- 8%, and radionuclide angiography ejection fraction was 47% +/- 9%, which represents a highly significant difference (p < 0.001) in techniques. Linear regression showed no correlation between the two techniques (r = 0.3; p = NS). No differences in results were observed in those studied simultaneously versus less than 4 hours. We conclude that the thermodilution technique underestimates right ventricular ejection fraction in heart transplant recipients and that its usefulness as a tool to screen for systolic dysfunction related to rejection is limited.     

Time course of physical reconditioning during exercise rehabilitation late after heart transplantation.

BACKGROUND: Exercise rehabilitation improves physical capacity in heart transplant recipients. The time course of physical reconditioning and skeletal muscle adaptation late after transplantation are unknown. METHODS: Twenty-one heart transplant recipients, at 5.2 +/- 2.1 years after transplantation, completed 1 year of an individually tailored home ergometer-training program (2.1 +/- 0.7 sessions weekly with matched heart rates, intensity at 10% below anaerobic threshold). We analyzed time course of physical reconditioning data for each home-training session (n = 2,396). Constant-load tests with consistent blood lactate concentrations were performed quarterly (n = 105) to estimate the time course of skeletal muscle adaptation. Nine heart transplant recipients served as a control group (CG). RESULTS: After 12 months, exercise capacity for matched heart rates (112 +/- 11 beats/min; CG, 114 +/- 8 beats/min) increased by 35% +/- 19% (from 43 +/- 14 to 58 +/- 18 W; p < 0.001; CG, 53 +/- 18 to 54 +/- 18 W); 24% of the increase was caused by improved skeletal muscle function and 11% by central functioning. Physical reconditioning showed its greatest increase within the first 3 months (+18%; p < 0.001); 50% of the increase consisted of better skeletal muscle or central functioning. Between the 4(th) and 12(th) months, exercise capacity increased continuously (+15%; p < 0.001), mainly because of better skeletal muscle functioning. CONCLUSIONS: The persistent improvement in exercise capacity along with consistent lactate concentrations during 12 months of training indicates that exercise training could counteract the negative side effects of immunosuppressive treatment on skeletal muscles. Even late after heart transplantation, physical training should be performed regularly to prevent the accelerated decrease in exercise capacity and in skeletal muscle function.     

Comparison of outcomes of double and single lung transplantation for obstructive lung disease. The Toronto Lung Transplant Group

Single lung transplantation has recently been applied with success in patients with obstructive lung disease. Such patients were previously managed by bilateral pulmonary transplantation. Between November 1986 and January 1990, 18 patients underwent transplantation for obstructive lung disease in our center. Eleven double lung transplants and seven single lung transplants were performed in patients having a mean age of 43.4 and 44.1 years, respectively. Operative death occurred in two of 11 double lung transplantations and one of seven single lung transplantations. Each patient underwent preoperative and 3-month postoperative pulmonary function tests, arterial blood gas analyses, nuclear lung scans, and 6-minute walk tests. There was no difference in the preoperative values for any of these parameters. Double lung recipients had significantly higher forced expiratory volume in 1 second and forced vital capacity than single lung recipients. However, the ratios of forced expiratory volume in 1 second to vital capacity were not different. Arterial oxygen and carbon dioxide tension were not different between the two procedures. Whereas double lung transplantations caused a slight preponderance of perfusion to the right lung, the transplanted lung in single lung recipients received a mean of 79.5% +/- 12.3% of predicted flow and only 61.6% +/- 5.0% of predicted ventilation. Three-month 6-minute walk distances were markedly improved in both groups, with double lung recipients achieving 573.0 +/- 44.7 m in comparison with the 528.0 +/- 43.0 m achieved by the single lung recipients. Single lung transplantation is a satisfactory option in patients with obstructive lung disease and might offer significant advantages to the older patient population, in which risk of double lung transplantation is high.     

Left ventricular dysfunction and dilatation resulting from chronic supraventricular tachycardia

It has been suggested that patients with chronic supraventricular tachycardia may have impaired ventricular function, which returns to normal after surgical procedures that eliminate the tachycardia. The purpose of this study was to determine the functional consequences of prolonged supraventricular tachycardia in 12 awake dogs in which permanent asynchronous atrial pacemakers were implanted and programmed to a rate of 190 +/- 5 beats/min. Serial radionuclide angiograms were obtained immediately after pacemaker activation and at regular intervals over a 3 month period. Chronic tachycardia resulted in a significantly depressed ejection fraction (49% +/- 1% to 29% +/- 3%; p less than 0.0005) compensated for by a dramatic increase in left ventricular end-diastolic volume (69 +/- 4 to 105 +/- 9 ml, p less than 0.005). Stroke volume and cardiac output were not significantly changed. Five dogs were allowed to recover, and serial radionuclide angiograms were obtained for 12 weeks. Although ejection fraction returned to control values (50% versus 47%, p = no significant difference), end-diastolic volume remained persistently elevated after a 12 week recovery period in all animals (67 +/- 5 versus 91 +/- 6 ml, p less than 0.05). Thus prolonged tachycardia resulted in significant functional changes associated with cardiac enlargement, which were not immediately reversible.     

Results of radionuclide assessment of cardiac function following transplantation of the heart

Radionuclide assessment of ejection fraction was determined early and late postoperatively following cardiac transplantation in 16 patients. In 11 patients, ejection fraction was determined within 48 hours of an endocardial biopsy. There was no relationship between the severity of histologically evident rejection and the ejection fraction (Pearson correlation coefficient [r] = -0.11; p = 0.47). In 2 patients, severe graft fibrosis developed with consequent diminution in ejection fraction. There was no relationship between severity and duration of rejection or the amount of immunosuppression required to treat acute rejection and the development of graft fibrosis. The mean resting ejection fraction in 7 patients in follow-up ranging from 6 to 21 months after transplantation was 0.59 +/- 0.06 (standard deviation), and the mean exercise ejection fraction in 6 of these patients was 0.72 +/- 0.08. Radionuclide-determined ejection fraction is not predictive of rejection early after operation. During short-term late follow-up, systolic left ventricular function at rest and exercise has been retained at normal levels.     

Improved right ventricular function following late pulmonary valve replacement for residual pulmonary insufficiency or stenosis

Residual severe pulmonary insufficiency or stenosis may result in significant myocardial dysfunction late after repair of tetralogy of Fallot. Although pulmonary valve replacement has been advocated for selected patients, objective improvement in right ventricular function has been difficult to demonstrate. We undertook pulmonary valve replacement in 11 patients to treat residual insufficiency (n = 8) or stenosis (n = 3) and evaluated them before and after operation by radionuclide ventriculography and M-mode echocardiography. Patients' age at the original repair was 6.6 +/- 0.6 years (range 2 to 8 years) and at subsequent valve replacement was 14.6 +/- 1.5 years (range 5 to 20 years). Indications for pulmonary valve replacement were conduit stenosis indicated by a gradient greater than or equal to 75 mm Hg (n = 3), symptoms (n = 2), progressive cardiomegaly (n = 3), and new onset of tricuspid insufficiency (n = 3). Prior to pulmonary valve replacement, right ventricular ejection fraction was 0.29 +/- 0.12 (range 0.12 to 0.48) and rose to 0.35 +/- 0.10 (range 0.19 to 0.48) at a mean of 10.5 +/- 2.3 months after operation (p less than 0.05). Improvement (defined as an increase in ejection fraction greater than 0.05) was noted in seven patients whereas four demonstrated no change. Left ventricular ejection fraction before operation (0.55 +/- 0.12) was unchanged after pulmonary valve replacement (0.54 +/- 0.06). M-mode echocardiography demonstrated significant reduction in right ventricular dilatation. Right ventricular/left ventricular end-diastolic dimension fell from 1.03 +/- 0.30 to 0.73 +/- 0.13 after operation (p less than 0.01). Cardiothoracic ratio fell from 0.59 +/- 0.02 to 0.55 +/- 0.02 at a mean of 12 months after pulmonary valve replacement (p less than 0.01). Subjective improvement in exercise tolerance was noted in all seven patients who showed an increase in right ventricular ejection fraction. Of the remaining four patients, two had no improvement, one felt symptomatically improved, and one was too young for evaluation. These data demonstrate objective improvement in right ventricular function following pulmonary valve replacement and confirm the usefulness of this procedure in patients with significant right ventricular dysfunction secondary to residual pulmonary insufficiency and stenosis.     

Effects of coronary revascularization on infarcted myocardial regions--evaluation on postoperative left ventricular regional wall motion during exercise

In order to determine the effects of coronary revascularization for infarcted regions on postoperative left ventricular function and regional wall motion, we studied first-pass radionuclide angiography at rest and during exercise before and after operation in 18 patients with previous myocardial infarction. Preoperative mean value of left ventricular ejection fraction (LVEF) was significantly decreased during exercise from 56.8 +/- 14.1% to 46.1 +/- 15.5% (p less than 0.01). Postoperatively, there was no change of the values between at rest and during exercise: 53.6 +/- 14.1% versus 51.9 +/- 15.7%. Postoperative mean LVEF during exercise was significantly higher, compared with that of preoperative LVEF (p less than 0.05). Mean regional ejection fraction of infarcted regions was significantly decreased during exercise from 66.0 +/- 15.0% to 56.1 +/- 15.8% (p less than 0.01) before operation. However, there was no significant change in values between at rest and during exercise after operation: 65.4 +/- 13.9% versus 61.8 +/- 14.5%. Mean postoperative regional ejection fraction during exercise was significantly higher, compared with preoperative regional ejection fraction after operation (p less than 0.05). These results might be indicated that regional wall motion of the infarcted regions with ischemia enhanced by exercise preoperatively can be definitely improved by coronary revascularization.     

Right ventricular morphology and function after pulmonary resection.

OBJECTIVE: To identify the effect of pulmonary resection on right ventricular performance and its possible contribution to mortality and morbidity. METHODS: Before and 2 days after pulmonary resection for primary lung cancer in 31 patients (21 males; ages 32-69 years), echocardiographic examinations of the right ventricle were performed. Systolic, diastolic and stroke volumes as well as right ventricular ejection fraction were estimated. Right ventricular volumes were calculated using the subtracting method. RESULTS: Right ventricular end-diastolic volume index increased significantly in patients after pneumonectomy: 80.4+/-7.2 ml/m2 versus preoperative evaluation: 66.1+/-5.2 ml/m2 (P = 0.031). In patients who underwent pneumonectomy right ventricular ejection fraction significantly decreased from 48+/-5.0% preoperatively to 39%+/-4.1% after surgery (P = 0.027). Fourteen patients after pneumonectomy had development of supraventricular arrhythmias postoperatively. These patients had much higher right ventricular end-diastolic volume index (76.3+/-6.4/82.1+/-7.4; P = 0.032) and lower right ventricular ejection fraction (42+/-4.3/37+/-3.9; P = 0.021) after surgery in comparison with patients who had normal sinus rhythm postoperatively. CONCLUSION: Pulmonary resection caused a significant dilatation and dysfunction of right ventricle in the early postoperative period. Early detection of deterioration in right ventricular function after pneumonectomy may provide the opportunity for interventional therapy.     

Comparative assessment of chordal preservation versus chordal resection during mitral valve replacement

Left ventricular function often deteriorates after mitral valve replacement for mitral regurgitation. It has been postulated that disruption of the mitral valve apparatus at operation is a major mechanism of postoperative dysfunction. The hypothesis tested in this investigation was that chordal preservation results in more favorable left ventricular function. Sixty-nine patients with isolated mitral regurgitation who underwent mitral valve replacement were studied before and 6 months after operation by treadmill exercise testing, catheterization, echocardiography, and radionuclide angiography. Nine patients underwent mitral valve replacement with preservation of the entire mitral apparatus and five with preservation of the posterior leaflet and attached chordae. The remaining 55 had mitral valve replacement with complete excision of the native valve. Preoperatively, there were no differences among groups in age, gender, exercise capacity, cardiac index, rest or exercise ejection fraction, fractional shortening, or pulmonary artery pressures. There were four perioperative deaths (7%) and eight late deaths among the 55 patients with chordal resection but no early or late deaths of patients whose chordae were preserved (p = 0.05). In patients in whom the chordae were excised, exercise capacity, left ventricular systolic dimensions, and cardiac index did not improve after mitral valve replacement, and left ventricular function deteriorated, as evidenced by a reduction of both the resting and exercise ejection fractions (from 46% +/- 13% to 31% +/- 13%, p = 0.0001, and from 49% +/- 12% to 37% +/- 14%, p = 0.0007, respectively) and fractional shortening (from 34% +/- 10% to 26% +/- 14%, p = 0.0001). In contrast, exercise capacity improved after mitral valve replacement in patients in whom the entire apparatus was spared (by 4 +/- 3 minutes, p = 0.05), left ventricular systolic dimensions decreased (from 44 +/- 8 to 36 +/- 9 mm, p = 0.03), and left ventricular function was maintained or improved, as evidenced by preservation of the resting ejection fraction (preoperative, 50% +/- 14%; postoperative, 54% +/- 11%; p = no significant difference), exercise ejection fraction (46% +/- 16% versus 52% +/- 9%, p = no significant difference), fractional shortening (from 31% +/- 9% to 28% +/- 9%, p = no significant difference), and an increase in the cardiac index (from 2.0 +/- 0.3 to 2.7 +/- 0.5 L/min/m2, p = 0.05). No statistically significant differences between posterior chordal resection only and preservation of the entire apparatus were found.(ABSTRACT TRUNCATED AT 250 WORDS)     

Factors that exaggerate the deleterious effects of pulmonary insufficiency on the right ventricle after tetralogy repair. Surgical implications

Postoperative cardiac catheterization data of 74 patients with pulmonary insufficiency after tetralogy repair were analyzed. Two groups were identified: Group A, 26 patients with normal right ventricular function (ejection fraction 95% +/- 5.5%, end-systolic volume 110% +/- 17% of predicted normal) and Group B, 48 patients with right ventricular dysfunction (ejection fraction 80% +/- 18% [p less than 0.001], and end-systolic volume 218% +/- 75% of predicted normal [p less than 0.001]). There was no significant difference between the two groups with respect to frequency of previous palliative procedures, age at operative repair, operative techniques, methods of myocardial protection, and follow-up period. Right ventricular dysfunction in Group B was associated with significant distal pulmonary stenosis (right ventricle-pulmonary artery pressure gradient 28 +/- 13 torr in Group A versus 55 +/- 20 torr in Group B, p less than 0.001), moderate pulmonary regurgitation (regurgitant fraction 18% +/- 11% in Group A versus 32% +/- 10% in Group B, p less than 0.001), and large transannular outflow patch (ratio of patch diameter to descending aorta diameter 1.31 +/- 0.16 in Group A versus 2.50 +/- 0.28 in Group B, p less than 0.001). Pulmonary valve insertion was performed in 42 patients in Group B. Eighteen had subsequent cardiac catheterization. Right ventricular function recovered completely (end-systolic volume 122% +/- 24%, and ejection fraction 92% +/- 7% of predicted) in five of six patients (83%) who had valve insertion within the first 2 years after tetralogy repair. In contrast, right ventricular function remained abnormal in all 12 patients who had valve insertion later than 2 years after tetralogy repair (p less than 0.05). Patients with residual pulmonary stenosis and/or a large transannular outflow patch are at risk for the development of right ventricular dysfunction from pulmonary insufficiency after tetralogy repair. Early correction of these residual lesions and control of pulmonary insufficiency may prevent long-term deterioration in right ventricular function.     

Heart rate-right ventricular stroke volume relation with myocardial revascularization

Whether increasing pacing frequency in cardiac surgical patients effectively improves right ventricular cardiac index depends on the interrelationships between heart rate, stroke volume index, and end-diastolic volume index. If an inverse relation exists between heart rate and right ventricular volume then the decrease in right ventricular ejection fraction described after bypass may be due, in part, to changes in heart rate. We evaluated the effects of pacing at 80, 95, and 110 beats/min using a thermodilution volumetric catheter in 16 patients undergoing myocardial revascularization. End-diastolic volume index, stroke volume index, and stroke work index were significantly greater after bypass than before bypass, whereas right ventricular ejection fraction remained constant. Before and after bypass, sequentially increasing pacing frequency from 80 to 110 beats/min decreased stroke volume index by 28% to 35% (p less than 0.001), end-diastolic volume index by 12% to 14% (p less than 0.001), and right ventricular ejection fraction by 18% to 24% (p less than 0.001). Right ventricular performance, assessed by comparing the stroke volume index to end-diastolic volume index and stroke work index to end-diastolic volume index relations generated during pacing, was not altered by bypass. We conclude that sequentially increasing heart rate from 80 to 110 beats/min fails to improve stroke volume index and consequently cardiac index before or after cardiac operations. Intraoperatively, in patients with normal left ventricular function, increasing pacing frequency decreases right ventricular ejection fraction due to simultaneous reductions in stroke volume index and end-diastolic volume index.     

Effects of elevated coronary sinus pressure on left ventricular function after the Fontan operation. An experimental and clinical correlation

An experimental model was devised to evaluate the effects of elevated coronary sinus pressure on left ventricular performance. Thirteen mongrel dogs were used. The coronary sinus was cannulated and its entire blood flow diverted into a reservoir. The pressure in the coronary sinus was increased from 5 to 25 torr by elevating the drainage reservoir in a stepwise fashion. Cardiac index, coronary arteriovenous difference, rate of rise of left ventricular pressure, left ventricular systolic time intervals, and coronary blood flow were measured. When the coronary sinus pressure reached 15 torr, there was a significant decrease in cardiac index (3.60 +/- 0.5 to 2.70 +/- 0.6 L/min/m2, p less than 0.001), coronary blood flow (13.7 +/- 3.1 to 7.0 +/- 2.1 ml/min, p less than 0.001), rate of rise of left ventricular pressure (1,567 +/- 275 to 1,331 +/- 314, p less than 0.05), and an increase in coronary arteriovenous difference (62.8% +/- 9.3% to 70.5% +/- 5.4% saturation, p less than 0.03). These experimental results were correlated with postoperative catheterization findings in 24 patients with the Fontan procedure. Patients with a mean right atrial pressure less than 15 torr had a left ventricular ejection fraction of 93% +/- 6% of predicted, whereas patients with a right atrial pressure of 15 torr or more had a left ventricular ejection fraction of 75% +/- 13% of predicted (p less than 0.001). These experimental and clinical data strongly suggest that elevated coronary sinus pressure has deleterious effects on ventricular function after the Fontan procedure. Modifications of the procedure, such as using the rudimentary right ventricle when feasible or diverting coronary sinus flow to the pulmonary venous atrium, might decrease coronary sinus hypertension and improve long-term results.     

Long-term outcome after coronary artery bypass grafting in patients with severe left ventricular dysfunction

BACKGROUND: The aim of this study was to define the potential for long-term survival with severe left ventricular dysfunction after coronary bypass and to quantify any improvement in overall functional status. METHODS: Left ventricular dysfunction was confirmed preoperatively and the long-term survival and functional outcome after bypass was determined by follow-up studies obtained during the span of a decade. RESULTS: From 1/1990 to 12/1999, 86 patients with severe left ventricular dysfunction (mean ejection fraction, 0.18 +/- 0.03; range, 0.10 to 0.20) underwent coronary artery bypass grafting. There were 10 perioperative deaths (11% mortality). The mean survival was 55 months (standard deviation +/- 34 months; range, 2 to 141 months) with an actual 5-year survival rate of 59% (actuarial 5-year 65%, 10-year 33%). Echocardiography obtained between 1 and 6 months, 6 months and 1 year, 1 and 2 years, 2 and 4 years, 4 and 6 years, and 6 and 11 years showed the ejection fraction improved to 0.29 +/- 0.08 (p < 0.001), 0.31 +/- 0.14 (p < 0.002), 0.35 +/- 0.08 (p < 0.001), 0.27 +/- 0.10 (p = 0.002), 0.36 +/- 0.14 (p = 0.004), and 0.30 +/- 0.11 (p = 0.004), respectively. At 1 to 6 months, 6 months to 1 year, and 1 to 2 years, the diastolic left ventricular dimension was unchanged, but the systolic left ventricular dimension decreased significantly from 5.02 +/- 0.77 cm to 4.26 +/- 0.91 cm (p = 0.046), 3.98 +/- 1.43 cm (p = 0.08), and 4.10 +/- 1.14 cm (p = 0.07). The preoperative New York Heart Association classification for all patients improved from 2.8 +/- 0.8 to 1.6 +/- 0.7 (p < 0.001) after a mean of 53 months (standard deviation +/- 34 months). CONCLUSIONS: Patients with severe left ventricular dysfunction can derive long-term benefit from coronary bypass through improved left ventricular contractility as documented by a significantly decreased systolic left ventricular dimension and increased ejection fraction. Successful bypass is associated with a 59% actual 5-year survival rate and significantly improved New York Heart Association functional class.     

Left ventricular aneurysm complicated by congestive heart failure: an analysis of long-term results and risk factors of surgical treatment

The results of surgical treatment of post-infarction left ventricular aneurysms in 49 patients with congestive heart failure preoperatively were analyzed. Average patient age was 55 years. Preoperative total ejection fraction averaged 30.5 +/- 1.5% (mean +/- SEM), contractile segment ejection fraction was 42.5 +/- 1.1% and end-diastolic volume of aneurysm was 81.4 +/- 10.4 ml. Seventy eight percent of patients underwent coronary artery bypass grafting concomitantly with aneurysmectomy. Mean follow-up after operation was 41.5 +/- 3.5 months. Hospital mortality was 8.2%, the 5 year survival rate was 70 +/- 7% and the 5 year complication free rate was 52 +/- 8%. Mean functional class of dyspnea improved significantly from 2.9 +/- 0.1 preoperatively to 1.6 +/- 0.1 at late follow-up (p less than 0.001). Likewise, isotopic ejection fraction at rest increased from 13.7 +/- 1.3% preoperatively to 30.9 +/- 3.0% postoperatively (p less than 0.0001). Logistic regression analysis isolated two factors which influenced postoperative survival independently: contractile segment ejection fraction (p = 0.045) and myocardial score of left anterior descending coronary artery (p = 0.035). Combining these two risk factors, it was possible to identify a low risk group of patients with a 5 year survival probability of 93 +/- 6%, contrasting with a high risk group of patients having a 5 year survival of 57 +/- 9% (p less than 0.02). Thus, resection of left ventricular aneurysms complicated by congestive heart failure provides improvement in left ventricular function and clinical status.(ABSTRACT TRUNCATED AT 250 WORDS)