Right and left ventricular area and function determined by two-dimensional echocardiography in adults with the Eisenmenger syndrome from a variety of congenital anomalies

Assessment of the Physiological Adaptations to Chronic Hypoxemia in Eisenmenger Syndrome

OBJECTIVE

Eisenmenger syndrome is characterized by severe and lifelong hypoxemia and pulmonary hypertension. Despite this, patients do surprisingly well and report a reasonable quality of life. The aim of this study was to investigate whether these patients undergo adaptation of their skeletal and cardiac muscle energy metabolism which would help explain this paradox.

DESIGN AND SETTING

Ten patients with Eisenmenger syndrome and eight age- and sex-matched healthy volunteers underwent symptom-limited treadmill cardiopulmonary exercise testing, transthoracic echocardiography and (31) P magnetic resonance spectroscopy of cardiac and skeletal muscle. Five subjects from each group also underwent near infrared spectroscopy to assess muscle oxygenation.

RESULTS

Despite having a significantly lower peak VO2 , patients with Eisenmenger syndrome have a similar skeletal muscle phosphocreatine (PCr) recovery, a measure of oxidative capacity, when compared to healthy controls (34.9 s ± 2.9 s vs. 35.2 s ± 1.7 s, P = .9). Furthermore their intracellular pH falls to similar levels during exercise suggesting they are not reliant on early anaerobic metabolism (0.3 ± 0.06 vs. 0.28 ± 0.04, P = .7). While their right ventricular systolic function remained good, the Eisenmenger group had a lower cardiac PCr/ATP ratio compared to the control group (1.55 ± 0.10 vs. 2.17 ± 0.15, P < .05).

CONCLUSIONS

These results show that adult patients with Eisenmenger syndrome have undergone beneficial physiological adaptations of both skeletal and cardiac muscle. This may, in part, explain their surprisingly good survival despite a lifetime of severe hypoxemia and adverse cardiopulmonary hemodynamics.

Impaired Right, Left, or Biventricular Function and Resting Oxygen Saturation Are Associated With Mortality in Eisenmenger Syndrome: A Clinical and Cardiovascular Magnetic Resonance Study

BACKGROUND

Patients with Eisenmenger syndrome (ES) have better survival, despite similar pulmonary vascular pathology, compared with other patients with pulmonary arterial hypertension. Cardiovascular magnetic resonance (CMR) is useful for risk stratification in idiopathic pulmonary arterial hypertension, whereas it has not been evaluated in ES. We studied CMR together with other noninvasive measurements in ES to evaluate its potential role as a noninvasive risk stratification test.

METHODS AND RESULTS

Between 2003 and 2005, 48 patients with ES, all with a post-tricuspid shunt, were enrolled in a prospective, longitudinal, single-center study. All patients underwent a standardized baseline assessment with CMR, blood test, echocardiography, and 6-minute walk test and were followed up for mortality until the end of December 2013. Twelve patients (25%) died during follow-up, mostly from heart failure (50%). Impaired ventricular function (right or left ventricular ejection fraction) was associated with increased risk of mortality (lowest quartile: right ventricular ejection fraction, <40%; hazard ratio, 4.4 [95% confidence interval, 1.4-13.5]; P=0.01 and left ventricular ejection fraction, <50%; hazard ratio, 6.6 [95% confidence interval, 2.1-20.8]; P=0.001). Biventricular impairment (lowest quartile left ventricular ejection fraction, <50% and right ventricular ejection fraction, <40%) conveyed an even higher risk of mortality (hazard ratio, 8.0 [95% confidence interval, 2.5-25.1]; P=0.0004). No other CMR or noninvasive measurement besides resting oxygen saturation (hazard ratio, 0.90 [0.83-0.97]/%; P=0.007) was associated with mortality.

CONCLUSIONS

Impaired right, left, or biventricular systolic function derived from baseline CMR and resting oxygen saturation are associated with mortality in adult patients with ES. CMR is a useful noninvasive tool, which may be incorporated in the risk stratification assessment of ES during lifelong follow-up.

Right ventricular function in patients with Eisenmenger syndrome

To evaluate (1) whether right ventricular (RV) dysfunction, evaluated using tricuspid annular plane systolic excursion (TAPSE) is associated with a worse outcome in patients with the Eisenmenger syndrome, (2) which variables are related to RV dysfunction, and (3) whether differences exist among simple pretricuspid, simple post-tricuspid, and combined shunt lesions. Patients with Eisenmenger syndrome, aged >18 years, who underwent echocardiography, were selected from the Belgian Eisenmenger registry and prospectively followed up using a Web-based registry. Cox regression analysis was performed to evaluate the relation to outcomes, defined as all-cause mortality, transplantation, and hospitalization for cardiopulmonary causes. Comparative and bivariate analysis was performed, where applicable. A total of 58 patients (mean age 35.1 ± 13.2 years, 32.8% men) were included. During a mean follow-up of 3.2 years, 22 patients (37.9%) reached the predefined end point. Only TAPSE (hazard ratio 0.820, 95% confidence interval 0.708 to 0.950; p = 0.008) was related to the adverse outcomes on multivariate analysis. Patients with pretricuspid shunt lesions were older (p <0.0001) had greater left (p <0.0001) and right atrial (p <0.0001) dimensions, greater RV dimensions (p = 0.002), and more tricuspid regurgitation (p = 0.012) compared to patients with post-tricuspid lesions. Lower TAPSE was related to the presence of pulmonary artery thrombosis (R = -0.378; p = 0.006). In conclusion, in patients with Eisenmenger syndrome, RV dysfunction, evaluated using TAPSE, is related to worse outcomes. Patients with Eisenmenger syndrome with pretricuspid shunt lesions were older and had greater left atrial, right atrial, and RV dimensions compared to patients with post-tricuspid lesions, indicating a difference in the RV response. Lower TAPSE was associated with the presence of pulmonary artery thrombosis.

Evaluating Operability in Adults with Congenital Heart Disease and the Role of Pretreatment with Targeted Pulmonary Arterial Hypertension Therapy

Despite recent advances in cardiac surgery that have allowed repair of congenital heart defects at a very young age, pulmonary arterial hypertension (PAH) secondary to congenital heart disease (CHD) remains a major problem. In its most severe form, the Eisenmenger syndrome, PAH and its complications result in a significant increase in morbidity and mortality and also greatly affect the quality of life of patients.

Severe pulmonary hypertension without right ventricular failure: the unique hearts of patients with Eisenmenger syndrome

Why adults with the Eisenmenger syndrome fare so much better than other patients with severe pulmonary hypertension is not known, but may be related to unique hemodynamics found only in these patients and in normal fetuses. We used echocardiography to evaluate ventricular morphology and function in 80 subjects: 45 cyanotic adults and 5 cyanotic adolescents with Eisenmenger syndrome, 10 infants with nonrestrictive ventricular septal defect and left-to-right shunt flow (pre-Eisenmenger phase), and 20 fetuses with structurally normal hearts. Cross-sectional morphology of the hearts was the same in all 4 groups with a flat ventricular septum throughout the cardiac cycle and equal thickness of the right and left ventricular free walls (regression slope 0.98, r = 0.97, p <0.0001). This morphology was the same in patients independent of age, defect type, and ventricular function. Right ventricular fractional area change was slightly inferior to that of the left ventricle but normal in most patients with Eisenmenger syndrome (0.47 +/- 0.14 vs 0.51 +/- 0.13, p <0.01). Overall, there was a highly significant linear relation between right and left ventricular function (r = 0.81, p <0.0001). The hearts of patients with Eisenmenger syndrome are more like normal fetal hearts than normal adult hearts. Because of the unique cardiovascular hemodynamics, regression of right ventricular wall thickness does not occur and is likely the reason that patients with Eisenmenger syndrome fare so much better than other adults with severe pulmonary hypertension.

Paradoxical relationship between N-terminal proatrial natriuretic peptide and filling pressure in adults with cyanotic congenital heart disease

BACKGROUND

Many adults with cyanotic congenital heart disease are characterized by reduced ventricular filling pressures and decreased systemic oxygen transport. Data from animals suggest that hypoxia can induce synthesis and secretion of atrial natriuretic peptide.

METHODS AND RESULTS

We measured plasma N-terminal (1-98) proatrial natriuretic peptide (proANP) in 26 cyanotic adults and 28 noncyanotic control subjects. Resting arterial oxygen saturation was significantly lower and hemoglobin concentration and hematocrit significantly greater in cyanotic patients than in control subjects (82+/-6 versus 96+/-3%, 19.7+/-2.2 versus 14.7+/-2.1 g/dL, and 59.0+/-8.5% versus 44.3+/-5.2%, respectively, P<.0001 in all cases). Four cyanotic patients had evidence of iron deficiency. Plasma proANP levels were elevated in cyanotic patients compared with control subjects (1828+/-1147 versus 689+/-343 pmol/L, P<.0001). Comparison of resting arterial oxygen saturation and proANP levels demonstrated an inverse linear relationship between the two measures (r=-.70, P<.0001). There was a significant linear relationship between both hemoglobin concentration and hematocrit and proANP levels as well (r=.53, P=.0003 and r=.48, P=.002, respectively). Cyanotic patients had lower mean right atrial pressures than the control subjects (4+/-3 versus 7+/-2 mm Hg, P=.005), and there were inverse logarithmic relationships between proANP levels and systemic cardiac index (r=-.82, P=.0002), systemic oxygen transport (r=-.68, P=.005), and mixed venous oxygen saturation (r=-.79, P<.0001).

CONCLUSIONS

Adults with cyanotic congenital heart disease are characterized by increased levels of plasma proANP. The increased atrial natriuretic peptide most likely results in extracellular and plasma volume depletion and reduced systemic oxygen transport. Measures designed to increase ventricular filling may improve quality of life of these patients.

Right ventricular dysfunction in low output syndrome after cardiac operations: assessment by transesophageal echocardiography

BACKGROUND

Low output syndrome after cardiac operations is associated with high morbidity and mortality rates. The contribution of right ventricular dysfunction to this syndrome has not been fully characterized. The purpose of this study was to evaluate the utility of transesophageal echocardiography to identify the frequency and the in-hospital mortality from right ventricular dysfunction in patients with this syndrome.

METHODS

Seventy-five consecutive patients undergoing transesophageal echocardiography for low output syndrome early after cardiac operations were evaluated. The findings from transesophageal echocardiography were correlated with the type of surgical procedure, cross-clamp time, right heart hemodynamics, and coronary angiography.

RESULTS

Right ventricular systolic dysfunction occurred in 36 patients (42%); in 17 patients it was isolated and in 19 patients it occurred in combination with left ventricular dysfunction. Postoperative right ventricular dysfunction was not uniformly associated with important right coronary artery disease or with prolonged ischemic time during cardiopulmonary bypass. Hemodynamic data were not useful to distinguish the group with postoperative right ventricular dysfunction. Patients with right ventricular dysfunction had a high (44%) in-hospital mortality rate.

CONCLUSIONS

Right ventricular dysfunction occurs frequently in patients with low output syndrome after cardiac operations and is associated with a high in-hospital mortality rate. Better understanding of the mechanisms causing postoperative right ventricular dysfunction may provide insight for preventing this complication.

Quantitative ultrasonic tissue characterization of myocardium in cyanotic adults with an unrepaired congenital heart defect

Adults with nonrestrictive ventricular septal defects have chronic hypoxemia that may lead to alterations in myocardial structure and function. Ultrasonic integrated backscatter provides quantitative assessment of myocardial acoustic properties that are altered by myocardial ischemia, fibrosis, and edema. Sixteen patients (age 31 +/- 10 years) with a nonrestrictive ventricular septal defect were studied using 2-dimensional and M-mode echocardiography with integrated backscatter imaging to determine the cyclic variation of integrated backscatter in the right ventricular free wall, ventricular septum, and left ventricular posterior wall. Cyclic variation of integrated backscatter in the right ventricular free wall and interventricular septum in patients was significantly less than that in control subjects (4.1 +/- 0.8 vs 4.9 +/- 1.0 decibels [dB], p = 0.02, and 3.8 +/- 1.2 vs 4.8 +/- 1.1 dB, p = 0.004, respectively). There was no difference between mean cyclic variation of integrated backscatter in the left ventricular posterior wall in patients and that in control subjects (4.7 +/- 1.3 vs 4.8 +/- 1.1 dB, p = NS, respectively). However, values < 4.0 dB were noted in 38% of patients compared with 15% of control subjects. Biventricular systolic function was normal in all but 1 patient. There was no correlation between backscatter and either wall thickness or percent wall thickening from the 3 regions. Histologic analysis of myocardial tissue in 3 patients revealed interstitial and replacement fibrosis. Adults with nonrestrictive ventricular septal defects exhibit alterations in tissue-acoustic properties detectable by integrated backscatter imaging despite preserved systolic function and wall thickening.