2015 ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension

Guidelines summarize and evaluate all available evidence on a particular issue at the time of the writing process, with the aim of assisting health professionals in selecting the best management strategies for an individual patient with a given condition, taking into account the impact on outcome, as well as the risk–benefit ratio of particular diagnostic or therapeutic means. Guidelines and recommendations should help health professionals to make decisions in their daily practice. However, the final decisions concerning an individual patient must be made by the responsible health professional(s) in consultation with the patient and caregiver as appropriate.

The Adult Patient with Eisenmenger Syndrome: A Medical Update after Dana Point Part II: Medical Treatment - Study Results

Eisenmenger syndrome is the most severe form of pulmonary arterial hypertension and arises on the basis of congenital heart disease with a systemic-to-pulmonary shunt. Due to the chronic slow progressive hypoxemia with central cyanosis, adult patients with the Eisenmenger syndrome suffer from a complex and multisystemic disorder including coagulation disorders (bleeding complications and paradoxical embolisms), renal dysfunction, hypertrophic osteoarthropathy, heart failure, reduced quality of life and premature death.

For a long time, therapy has been limited to symptomatic options or lung or combined heart-lung transplantation. As new selective pulmonary vasodilators have become available and proven to be beneficial in various forms of pulmonary arterial hypertension, this targeted medical treatment has been expected to show promising effects with a delay of deterioration also in Eisenmenger patients. Unfortunately, data in Eisenmenger patients suffer from small patient numbers and a lack of randomized controlled studies.

To optimize the quality of life and the outcome, referral of Eisenmenger patients to spezialized centers is required. In such centers, specific interdisciplinary management strategies of physicians specialized on congenital heart diseases and PAH should be warranted.

This medical update emphasizes the current diagnostic and therapeutic options for Eisenmenger patients with particularly focussing on the medical treatment and corresponding study results.

The Adult Patient with Eisenmenger Syndrome: A Medical Update after Dana Point Part III: Specific Management and Surgical Aspects

Eisenmenger syndrome is the most severe form of pulmonary arterial hypertension and arises on the basis of congenital heart disease with a systemic-to-pulmonary shunt. Due to the chronic slow progressive hypoxemia with central cyanosis, adult patients with the Eisenmenger syndrome suffer from a complex and multisystemic disorder including coagulation disorders (bleeding complications and paradoxical embolisms), renal dysfunction, hypertrophic osteoarthropathy, heart failure, reduced quality of life and premature death.

For a long time, therapy has been limited to symptomatic options or lung or combined heart-lung transplantation. As new selective pulmonary vasodilators have become available and proven to be beneficial in various forms of pulmonary arterial hypertension, this targeted medical treatment has been expected to show promising effects with a delay of deterioration also in Eisenmenger patients. Unfortunately, data in Eisenmenger patients suffer from small patient numbers and a lack of randomized controlled studies.

To optimize the quality of life and the outcome, referral of Eisenmenger patients to spezialized centers is required. In such centers, specific interdisciplinary management strategies of physicians specialized on congenital heart diseases and PAH should be warranted.

This medical update emphasizes the current diagnostic and therapeutic options for Eisenmenger patients with particularly focussing on specific management and surgical aspects.

The adult patient with eisenmenger syndrome: a medical update after dana point part I: epidemiology, clinical aspects and diagnostic options

Eisenmenger syndrome is the most severe form of pulmonary arterial hypertension and arises on the basis of congenital heart disease with a systemic-to-pulmonary shunt. Due to the chronic slow progressive hypoxemia with central cyanosis, adult patients with the Eisenmenger syndrome suffer from a complex and multisystemic disorder including coagulation disorders (bleeding complications and paradoxical embolisms), renal dysfunction, hypertrophic osteoarthropathy, heart failure, reduced quality of life and premature death.For a long time, therapy has been limited to symptomatic options or lung or combined heart-lung transplantation. As new selective pulmonary vasodilators have become available and proven to be beneficial in various forms of pulmonary arterial hypertension, this targeted medical treatment has been expected to show promising effects with a delay of deterioration also in Eisenmenger patients. Unfortunately, data in Eisenmenger patients suffer from small patient numbers and a lack of randomized controlled studies.To optimize the quality of life and the outcome, referral of Eisenmenger patients to spezialized centers is required. In such centers, specific interdisciplinary management strategies of physicians specialized on congenital heart diseases and PAH should be warranted. This medical update emphasizes the current diagnostic and therapeutic options for Eisenmenger patients with particularly focussing on epidemiology, clinical aspects and specific diagnostic options.

Recommendations for cardiovascular magnetic resonance in adults with congenital heart disease from the respective working groups of the European Society of Cardiology

This paper aims to provide information and explanations regarding the clinically relevant options, strengths, and limitations of cardiovascular magnetic resonance (CMR) in relation to adults with congenital heart disease (CHD). Cardiovascular magnetic resonance can provide assessments of anatomical connections, biventricular function, myocardial viability, measurements of flow, angiography, and more, without ionizing radiation. It should be regarded as a necessary facility in a centre specializing in the care of adults with CHD. Also, those using CMR to investigate acquired heart disease should be able to recognize and evaluate previously unsuspected CHD such as septal defects, anomalously connected pulmonary veins, or double-chambered right ventricle. To realize its full potential and to avoid pitfalls, however, CMR of CHD requires training and experience. Appropriate pathophysiological understanding is needed to evaluate cardiovascular function after surgery for tetralogy of Fallot, transposition of the great arteries, and after Fontan operations. For these and other complex CHD, CMR should be undertaken by specialists committed to long-term collaboration with the clinicians and surgeons managing the patients. We provide a table of CMR acquisition protocols in relation to CHD categories as a guide towards appropriate use of this uniquely versatile imaging modality.

Late presentation of pulmonary valve stenosis confirmed by cardiovascular magnetic resonance

We describe the case of a 70-year-old man who presented with increasing exertional dyspnea. He was found to have an ejection systolic murmur and evidence of right ventricular outflow tract obstruction, with a peak velocity of 4.5 m/s recorded by transthoracic Doppler echocardiography. Cardiovascular magnetic resonance showed right ventricular hypertrophy, pulmonary valve stenosis, peak recorded velocity 4.2 m/s, with thickened pulmonary valve leaflets of reduced mobility, and poststenotic dilatation of the main pulmonary artery. The case illustrates that severe pulmonary valve stenosis can present late in life and that cardiovascular magnetic resonance can be useful in clarifying nature and level of right ventricular outflow tract obstruction in an adult.

Fate of undifferentiated mouse embryonic stem cells within the rat heart: role of myocardial infarction and immune suppression

Abstract It has recently been suggested that the infarcted rat heart microenvironment could direct pluripotent mouse embryonic stem cells to differentiate into cardiomyocytes through an in situ paracrine action. To investigate whether the heart can function as a cardiogenic niche and confer an immune privilege to embryonic stem cells, we assessed the cardiac differentiation potential of undifferentiated mouse embryonic stem cells (mESC) injected into normal, acutely or chronically infarcted rat hearts. We found that mESC survival depended on immunosuppression both in normal and infarcted hearts. However, upon Cyclosporin A treatment, both normal and infarcted rat hearts failed to induce selective cardiac differentiation of implanted mESC. Instead, teratomas developed in normal and infarcted rat hearts 1 week and 4 weeks (50% and 100%, respectively) after cell injection. Tight control of ESC commitment into a specific cardiac lineage is mandatory to avoid the risk of uncontrolled growth and tumourigenesis following transplantation of highly plastic cells into a diseased myocardium.

Late cardiac tamponade after percutaneous closure of a patent foramen ovale

We report the case of a 35-year-old man who had a transient ischemic cerebral attack and then underwent a percutaneous closure of the patent foramen ovale (PFO) with a Cardiastar device. One year later, the patient developed a cardiac tamponade due to an important hemorrhagic pericardial effusion. Transoesophageal echocardiography showed that one of the struts had impinged on the aortic root in the region adjacent to the transverse pericardial sinus. Therefore, we speculated that the strut had passed through the aortic wall by slow erosion, leading to the pericardial effusion. Cardiac CT and subsequent surgery confirmed the perforation of the left atrial roof and the aortic root by two struts of the device. This is the first reported case of late cardiac tamponade and underscores the importance of long-term follow-up after PFO closure device implantation.

Coarctation of the aorta: pre and postoperative evaluation with MRI and MR angiography; correlation with echocardiography and surgery

AIMS

To compare MRI and MRA with Doppler-echocardiography (DE) in native and postoperative aortic coarctation, define the best MR protocol for its evaluation, compare MR with surgical findings in native coarctation.

MATERIALS AND METHODS

136 MR studies were performed in 121 patients divided in two groups: Group I, 55 preoperative; group II, 81 postoperative. In group I, all had DE and surgery was performed in 35 cases. In group II, DE was available for comparison in 71 cases. MR study comprised: spin-echo, cine, velocity-encoded cine (VEC) sequences and 3D contrast-enhanced MRA.

RESULTS

In group I, diagnosis of coarctation was made by DE in 33 cases and suspicion of coarctation and/or aortic arch hypoplasia in 18 cases. Aortic arch was not well demonstrated in 3 cases and DE missed one case. There was a close correlation between VEC MRI and Doppler gradient estimates across the coarctation, between MRI aortic arch diameters and surgery but a poor correlation in isthmic measurements. In group II, DE detected a normal isthmic region in 31 out of 35 cases. Postoperative anomalies (recoarctation, aortic arch hypoplasia, kinking, pseudoaneurysm) were not demonstrated with DE in 50% of cases.

CONCLUSIONS

MRI is superior to DE for pre and post-treatment evaluation of aortic coarctation. An optimal MR protocol is proposed. Internal measurement of the narrowing does not correspond to the external aspect of the surgical narrowing.

Severe Left Ventricular Dysfunction Secondary to Primary Pulmonary Hypertension: Bridging Therapy With Bosentan Before Lung Transplantation

When right ventricular failure develops secondary to primary pulmonary hypertension, right-left ventricular interaction may lead to severe impairment of left ventricular function. In such cases, many experts favor combined heart-lung transplantation by fear that the left ventricle may not recover after transplantation of the lungs alone. We report a case of primary pulmonary hypertension with severely diminished right and left ventricular function. The patient was rendered amenable to isolated pulmonary transplantation with the endothelin-receptor antagonist bosentan. The medication improved right and left ventricular function to the point that heart transplantation no longer appeared necessary. After double-lung transplantation the patient's cardiac function made a full recovery. This approach might be particularly welcome considering both the current donor organ shortage and the limited number of surgical teams with expertise in heart-lung transplantation.

Thoracic aortic plaques, transoesophageal echocardiography and coronary artery disease

BACKGROUND

The purpose of this study was to assess whether the detection of atherosclerotic aortic plaques by transoesophageal echocardiography (TEE) could be used as a marker of coronary artery disease (CAD), relying on their number, cross-sectional surface, depth and localisation.

METHODS

The thoracic aortas of 102 consecutive patients (77 men, mean age 67 +/- 12 years) undergoing elective cardiac surgery were assessed by TEE. Atherosclerotic plaques were defined as > or = 5 mm thick focal hyperechogenic zones of the aortic intima and/or lumen irregularities with mobile structures or ulcerations. All patients had undergone prior coronary angiography.

RESULTS

Thoracic aortic plaques were present in 73 patients, 66 of whom had CAD. The presence of aortic plaques detected by TEE identified significant coronary artery disease with a sensitivity of 90% and a specificity of 76%. The maximum transverse cross-sectional plaque area, the maximum plaque depth and the total plaque number all correlated significantly with the presence of CAD, but not with its severity. Multivariate regression analysis showed that aortic plaques, hypertension and hypercholesterolaemia were significant predictors of CAD, but aortic plaques were the most significant predictor regardless of age and sex.

CONCLUSIONS

This study suggests that detection of atherosclerotic aortic plaques is a useful marker of significant coronary artery disease. Absence of plaques in the patients aged over 70 identified a subgroup with a very low probability of CAD.

Thoracic aortic plaques, transoesophageal echocardiography and coronary artery disease

BACKGROUND

The purpose of this study was to assess whether the detection of atherosclerotic aortic plaques by transoesophageal echocardiography (TEE) could be used as a marker of coronary artery disease (CAD), relying on their number, cross-sectional surface, depth and localisation.

METHODS

The thoracic aortas of 102 consecutive patients (77 men, mean age 67 +/- 12 years) undergoing elective cardiac surgery were assessed by TEE. Atherosclerotic plaques were defined as > or = 5 mm thick focal hyperechogenic zones of the aortic intima and/or lumen irregularities with mobile structures or ulcerations. All patients had undergone prior coronary angiography.

RESULTS

Thoracic aortic plaques were present in 73 patients, 66 of whom had CAD. The presence of aortic plaques detected by TEE identified significant coronary artery disease with a sensitivity of 90% and a specificity of 76%. The maximum transverse cross-sectional plaque area, the maximum plaque depth and the total plaque number all correlated significantly with the presence of CAD, but not with its severity. Multivariate regression analysis showed that aortic plaques, hypertension and hypercholesterolaemia were significant predictors of CAD, but aortic plaques were the most significant predictor regardless of age and sex.

CONCLUSIONS

This study suggests that detection of atherosclerotic aortic plaques is a useful marker of significant coronary artery disease. Absence of plaques in the patients aged over 70 identified a subgroup with a very low probability of CAD.

Bentall procedure using cryopreserved valved aortic homografts: mid- to long-term results

The Bentall procedure is the standard operation for patients who have lesions of the ascending aorta associated with aortic valve disease. In many cases, however, mechanical prosthetic conduits are not suitable. There are few reports in the English-language medical literature concerning the mid- to long-term outcome of Bentall operations with cryopreserved homografts. Therefore, we reviewed our experience with this procedure and valved homografts. From January 1997 through December 2002, 21 patients underwent a Bentall operation with cryopreserved homografts at our institution. There were 14 males and 7 females; the mean age was 36 +/- 21 years (range, 15-74 years). Eleven patients had undergone previous aortic valve surgery. All patients had aortic dilatation or aneurysms involving the ascending aorta. Indications for surgery included aortic valve stenosis or insufficiency, and aortic valve endocarditis (native valve or prosthetic). One patient had Takayasu's arteritis and 3 had Marfan syndrome. There was 1 hospital death (due to sepsis), but no other major postoperative complications. The mean hospital stay was 14 +/- 7 days. Follow-up echocardiographic and computed tomographic scans were performed yearly. The mean follow-up was 34 months (6-72 months). Follow-up imaging revealed no calcifications or degenerative processes related to the homograft. Four patients had minimal valve regurgitation. Two patients died during follow-up. The 3-year actuarial survival rate was 85.7%. Our data suggest that the Bentall procedure with a valved homograft conduit is a safe procedure with excellent mid- to long-term results, comparable to results reported with aortic valve replacement with a homograft.

Vasopeptidase inhibitors: potential role in the treatment of heart failure

Current thinking views the progression of heart failure as the result of sustained activation of vasoconstrictor neurohormones. In this model, the sustained synthesis of vasoconstrictor neurohormones leads to disease progression through alterations in cardiomyocyte structure and function, which affects myocardial contractility, cardiac metabolism, and cellular growth. Ultimately, these events induce irreversible adverse ventricular remodeling through myocyte cell loss and progressive myocardial fibrosis. In the past decade, several landmark clinical trials tested the neurohormonal hypothesis, by targeting the activation of both the beta-adrenergic and the renin-angiotensin-aldosterone systems. Although the observed decrease in mortality using this strategy in heart failure populations was encouraging, morbidity and mortality levels remained elevated, and it has now been shown that several other humoral interactions are at play and potentially deserve antagonizing, or in the case of vasodilator neurohormones, deserve stimulation. It is known a family of vasodilator neurohormones - the natriuretic peptides - that have natriuretic, vasodilatory, and antiproliferative effects, endogenously inhibit the renin-angiotensin system. These peptides are degraded primarily by a neutral endopeptidase (NEP), an endothelial cell-surface zinc metallopeptidase, which shares a similar structure and catalytic site with the angiotensin converting enzyme (ACE). NEPs have broad substrate specificity, encompassing atrial natriuretic peptide, brain natriuretic peptide, and C-type natriuretic peptide, but also bradykinin and adrenomedullin. The recognition that ACE and NEP enzymes had related structures, led to the design and development of a class of molecules with a dual inhibitory effect on ACE and NEP, referred to as vasopeptidase inhibitors. Preliminary clinical trials in heart failure with vasopeptidase inhibitors have become available and show promising results. Thus, the combined inhibition of ACE and NEP, by attenuating excessive vasoconstriction and enhancing vasodilator substances, holds promise as a valuable option in heart failure treatment for the near future.

Circumferential dissection with intimal intussusception: an unusual case of acute aortic type A dissection

An unusual case of a type-A aortic dissection with complete circumferential dissection just above the aortic valve with intimointimal intussuseption just distal to the left subclavian artery partially obstructing the descending aorta is described. CT-scan and transesophageal echocardiography together with clinical suspicion led to the correct diagnosis. Intimointimal intussusception is an unusual type of aortic dissection in which a proximal circumferential tear causes dissection with intussusception of the torn intima downstream, which could cause confusion about the appropriate diagnosis ([1]). It is a very infrequent complication of aortic dissection with only a few cases reported in the literature ([2-6]). CT scan and transesophageal echocardiography are the most accurate diagnostic tools ([7-9]). We describe a patient with intimointimal intussusception, diagnosed by CT scan and transesophageal echocardiography.

Automatic cardiac output measurement (ACOM): clinical applications of a new noninvasive tool

This study sought to validate a new noninvasive method to measure cardiac output, in the clinical setting, using color Doppler flow integration. This method, the automatic cardiac output measurement (ACOM), using color Doppler was recently developed and validated in vitro. ACOM was performed at the aortic valve and in the left ventricular outflow tract in 106 subjects (60 men, mean age 52 +/- 18) and compared with the echocardiographic pulsed-wave Doppler and a 2-D volume method. In 14 patients the noninvasive methods were correlated with the thermodilution technique. ACOM was feasible in 101 subjects (95%). The correlation factor between the values obtained with ACOM in the apical 5-chamber view and apical long-axis view was 0.75 at the aortic valve and 0.74 in the left ventricular outflow tract. Interoperator variability for ACOM in the apical 5-chamber and apical long-axis views were 0.93 and 0.75, respectively. The best comparison of ACOM with the pulsed-wave echo-Doppler technique occurred in the apical long-axis view (n = 79, r = 0.62), whereas the correlation with the 2-D volume method was poor. The most favorable comparison of ACOM with the thermodilution technique (n = 14) was also obtained in the apical long-axis view (5.408 +/- 1.72 vs. 3.356 +/- 1.281/min. [mean +/- SD], r = 0.71). Assuming the thermodilution technique as 'gold standard', the pulsed-wave echo-Doppler technique showed a better correlation (5.408 +/- 1.72 vs. 4.664 +/- 1.281/min., r = 0.84). ACOM is a useful, reproducible, noninvasive tool for rapid automated measurements of cardiac output. There is, however, an underestimation when compared with the pulsed-wave Doppler echocardiography and the thermodilution techniques. Good 2-D echocardiographic images, adequate color filling of the outflow tract and high frame rates are prerequisites for accurate values. Further refinements of this new technique are needed to enhance its clinical value in the future.

Use of assumed versus measured oxygen consumption for the determination of cardiac output using the Fick principle

Assumed oxygen consumption (VO2) is increasingly used as a convenient surrogate for measured VO2 for calculation of cardiac output. This substitution is often based on empirical formulae, previously validated only in relatively young patients. To assess the inaccuracy introduced by extrapolating these formulae to older patients, we compared measured VO2 with assumed VO2 in 57 patients. VO2 was measured using an open circuit analyzer. Assumed VO2 was calculated according to the LaFarge or Bergstra formulae. Agreement between both methods was assessed according to the method of Bland and Altman. The mean difference of measured VO2 minus assumed VO2 was 7.9 ml/min/m2 (P < 0.02) using the LaFarge formula, and -15.6 ml/min/m2 (P < 0.0002) using the Bergstra formula across a range of measured VO2 from 70 to 176 ml/min/m2. A systematic error was introduced by assumed VO2 from both formulae of underestimating higher and overestimating lower values of VO2, resulting in poor overall agreement with measured VO2. The same error and poor agreement was found when analyzing subgroups of patients > or =60 or <70 years of age. In summary, use of assumed VO2 introduces large, unpredictable errors in adult patients, suggesting requirement for measurement of VO2 when calculating cardiac output.

Mechanisms of natriuretic-peptide-induced growth inhibition of vascular smooth muscle cells

OBJECTIVE

While natriuretic peptides can inhibit growth of vascular muscle cells (VSMC), controversy exists as to whether this effect is mediated via the guanylate cyclase-coupled receptors, NPR-A and NPR-B, or the clearance receptor, NPR-C. The original aim of this study was to examine the mechanism by which the NPR-C receptor regulates growth.

METHODS

Rat VSMC were characterized with regard to natriuretic peptide receptor expression by RT/PCR and radioligand binding studies. The effect on growth following addition of the peptides and the ligands for NPR-C was measured by [3H]thymidine incorporation. Cyclic guanosine monophosphate (cGMP) levels were determined by radioimmunoassay and mitogen activating protein kinase activity was based on the phosphorylation of myelin basic protein.

RESULTS

In rat VSMC, passages 4-12, both atrial natriuretic peptide (ANP) and C-type natriuretic peptide (CNP) dose-dependently inhibited serum and PDGF-induced VSMC growth. In contrast, NPR-C specific ligands alone had no effect on cell growth but enhanced growth inhibition when co-administered with ANP and CNP. ANP and CNP also decreased PDGF-BB-stimulated MAP kinase activity. Once again, NPR-C specific ligands alone had no effect but enhanced the effects of ANP. Furthermore, a cGMP specific phosphodiesterase inhibitor dose-dependently inhibited VSMC growth and markedly enhanced natriuretic-peptide-induced inhibition at low peptide concentrations. To examine a potential mechanism for the controversy concerning the NPR-C, we investigated the autocrine expression of ANP and CNP by VSMC and found that mRNA encoding both peptides could be detected by RT/PCR.

CONCLUSION

Our findings indicate that the guanyl-cyclase-linked receptors mediate the antiproliferative actions of the natriuretic peptides on vascular smooth muscle cell growth. Moreover, we hypothesize that the apparent inhibition of growth by NPR-C specific ligands reported by others may be due to stabilization of natriuretic peptides produced by the cultured VSMC and subsequent action of these peptides at guanyl-cyclase-linked receptors.

Analysis of deaths in patients awaiting heart transplantation: impact on patient selection criteria

OBJECTIVE

To analyse the clinical characteristics of patients who died on the Stanford heart transplant waiting list and to develop a method for risk stratifying status 2 patients (outpatients).

METHODS

Data were reviewed from all patients over 18 years, excluding retransplants, who were accepted for heart transplantation over an eight year period from 1986 to 1994.

RESULTS

548 patients were accepted for heart transplantation; 53 died on the waiting list, and 52 survived on the waiting list for over one year. On multivariate analysis only peak oxygen consumption (peak VO2: 11.7 (SD 2.7) v 15.1 (5.2) ml/kg/min, P = 0.02) and cardiac output (3.97 (1.03) v 4.79 (1.06) litres/min, P = 0.04) were found to be independent prognostic risk factors. Peak VO2 and cardiac index (CI) were then analysed in the last 141 consecutive patients accepted for cardiac transplantation. All deaths and 88% of the deteriorations to status 1 on the waiting list occurred in patients with either a CI < 2.0 or a VO2 < 12. In those with a CI < 2.0 and a VO2 < 12, 38% died or deteriorated to status 1 in the first year on the waiting list. Patients with CI > or = 2.0 and a VO2 > or = 12 all survived throughout follow up. Using a Cox's proportional hazards model with CI and peak VO2 as covariates, tables were constructed predicting the chance of surviving for (a) 60 days and (b) 1 year on the waiting list.

CONCLUSIONS

These data provide a basis for risk stratification of status 2 patients on the heart transplant waiting list.

Transplant candidates with severe left ventricular dysfunction managed with medical treatment: characteristics and survival

OBJECTIVES

This study sought to assess the clinical characteristics and survival of patients with symptomatic heart failure who were referred as potential heart transplant candidates, but were selected for medical management.

BACKGROUND

Patients with severe left ventricular dysfunction referred for heart transplantation may be considered too well to be placed immediately on an active waiting transplant list. The clinical characteristics of this patient group and their survival have not been well defined. These patients represent a unique group that are characterized by comparatively low age and freedom from significant comorbid conditions.

METHODS

We studied 116 consecutive patients with symptomatic heart failure, severe left ventricular dysfunction (left ventricular ejection fraction 20 +/- 7% [mean +/- SD]) and duration of symptoms >1 month referred for heart transplantation, who were acceptable candidates for the procedure but who were not listed for transplantation because of relative clinical stability. These patients were followed up closely on optimal medical therapy. A variety of baseline clinical, hemodynamic and exercise variables were assessed to define this patient group and used to predict cardiac death and requirement later for heart transplantation.

RESULTS

During a mean follow-up period of 25.0 +/- 14.8 months (follow-up 99% complete), there were eight cardiac deaths (7%) (seven sudden, one acute myocardial infarction). Only nine patients (8%) were listed for heart transplantation. Actuarial 1- and 4-year cardiac survival rates were 98 +/- 1% and 84 +/- 7% (mean +/- SE), respectively, and freedom from listing for transplantation was 95 +/- 2% and 84 +/- 7% (mean +/- SE), respectively. Patients were mainly in New York Heart Association functional class II or III and had a preserved cardiac index (2.4 liters/min.m2), pulmonary capillary wedge pressure of 16 +/- 9 mm Hg (mean +/- SD) and maximal oxygen consumption of 17.4 +/- 4.3 ml/min per kg (mean +/- SD). By logistic regression analysis, there was no predictor for cardiac death. Longer duration of heart failure (p = 0.013) and mean pulmonary artery (p < 0.05) and pulmonary systolic (p = 0.014) and diastolic (p < 0.05) pressures correlated significantly with listing for heart transplantation by univariate logistic regression. By multivariate logistic regression, only pulmonary artery systolic pressure (p < 0.004) and duration of heart failure (p < 0.015) remained as predictors for need for later transplantation.

CONCLUSIONS

In the current treatment era, prognosis is favorable in a definable group of transplant candidates despite severe left ventricular dysfunction. This patient group can be identified after intensive medical therapy by stable symptoms, a relatively high maximal oxygen uptake at peak exercise and a preserved cardiac output.

Expression of inducible nitric oxide synthase in human heart failure

BACKGROUND

There is increasing evidence that alterations in nitric oxide synthesis are of pathophysiological importance in heart failure. A number of studies have shown altered nitric oxide production by the endothelial constitutive isoform of nitric oxide synthase (NOS), but there is very little information on the role of the inducible isoform.

METHODS AND RESULTS

We analyzed inducible NOS (iNOS) expression in ventricular myocardium taken from 11 control subjects (who had died suddenly from noncardiac causes), from 10 donor hearts before implantation, and from 51 patients with heart failure (24 with dilated cardiomyopathy [DCM], 17 with ischemic heart disease [IHD], and 10 with valvular heart disease [VHD]). Reverse transcription-polymerase chain reaction was used to confirm the presence of intact mRNA and to detect expression of iNOS and atrial natriuretic peptide (ANP). ANP was used as a molecular phenotypic marker of ventricular failure. iNOS was expressed in 36 of 51 biopsies (71%) from patients with heart failure and in none of the control patients (P<.0001). iNOS expression could also be detected in 50% of the donor hearts. All samples that expressed iNOS also expressed ANP. iNOS gene expression occurred in 67% of patients with DCM, 59% of patients with IHD, and 100% of patients with VHD. To determine whether iNOS protein was expressed in failing ventricles, immunohistochemistry was performed on three donor hearts and nine failing hearts with iNOS mRNA expression. Staining for iNOS was almost undetectable in the donor myocardium and in control sections, but all failing hearts showed diffuse cytoplasmic staining in cardiac myocytes. Expression of iNOS could be observed in all four chambers. Western blot analysis with the same primary antibody showed a specific positive band for iNOS protein in the heart failure specimens; minimal iNOS protein expression was seen in donor heart samples.

CONCLUSIONS

iNOS expression occurs in failing human cardiac myocytes and may be involved in the pathophysiology of DCM, IHD, and VHD.

Induction of nitric oxide synthase in the human cardiac allograft is associated with contractile dysfunction of the left ventricle

BACKGROUND

The mechanisms underlying cardiac contractile dysfunction after transplantation remain poorly defined. Previous work has revealed that inducible nitric oxide synthase (iNOS) is expressed in the rat heterotopic cardiac allograft during rejection; resultant overproduction of nitric oxide (NO) might cause cardiac contractile dysfunction via the negative inotropic and cytotoxic actions of NO. In this investigation, we tested the hypothesis that induction of iNOS may occur and be associated with cardiac allograft contractile dysfunction in humans.

METHODS AND RESULTS

We prospectively studied 16 patients in the first year after cardiac transplantation at the time of serial surveillance endomyocardial biopsy. Clinical data, the results of biopsy histology, and echocardiographic and Doppler evaluation of left ventricular systolic and diastolic function were recorded. Total RNA was extracted from biopsy specimens, and mRNA for beta-actin, detected by reverse transcription-polymerase chain reaction (RT-PCR) using human specific primers, was used as a constitutive gene control; iNOS mRNA was similarly detected by RT-PCR using human specific primers. iNOS protein was detected in biopsy frozen sections by immunofluorescence. Myocardial cGMP was measured by radioimmunoassay, and serum nitrogen oxide levels (NOx = NO2 + NO3) were measured by chemiluminescence. iNOS mRNA was detected in allograft myocardium at some point in each patient and in 59 of 123 biopsies (48%) overall. In individual patients, iNOS mRNA expression was episodic and time dependent; the frequency of expression was highest during the first 180 days after transplant (P = .0006). iNOS protein associated with iNOS mRNA was detected by immunofluorescence in cardiac myocytes. iNOS mRNA expression was not related to the ISHLT histological grade of rejection or to serum levels of NOx but was associated with increased levels of myocardial cGMP (P = .01) and with both systolic (P = .024) and diastolic (P = .006) left ventricular contractile dysfunction measured by echocardiography and Doppler.

CONCLUSIONS

These data support a relation between iNOS mRNA expression and contractile dysfunction in the human cardiac allograft.