Andreas Kühn

Impaired Elastic Properties of the Ascending Aorta in Newborns Before and Early After Successful Coarctation Repair Proof of a Systemic Vascular Disease of the Prestenotic Arteries

Background—Despite successful surgical correction, morbidity of patients with coarctation of the aorta is increased. It is well known that these patients have impaired elastic properties of the prestenotic arteries. To find out whether these abnormalities are primarily present or develop later, we studied 17 newborns before and early after surgical repair. Methods and Results—Aortic wall stiffness index and distensibility were calculated using ascending and abdominal aortic diameters determined by M-mode echocardiography and noninvasive estimation of aortic pulse pressure in the right arm and leg. Seventeen patients with aortic coarctation (mean age, 20±26 days) were compared with 17 normal neonates (mean age, 13±7 days) preoperatively and postoperatively (10±6 days after surgery). Ascending aortic distensibility in patients was significantly reduced preoperatively (79±58 versus 105±36; P=0.03) and postoperatively (65±24 versus 105±36; P<0.005). Preoperative and postoperative ascending aortic stiffness index was higher in patients (preoperative, 5.2±4.4 versus 2.7±0.9; P=0.04; postoperative, 4.0±1.6 versus 2.7±0.9; P<0.005). Elastic properties of the descending aorta did not differ preoperatively or postoperatively compared with those in normal subjects. Conclusions—Elastic properties of the prestenotic aorta of patients with coarctation seem to be impaired primarily, even in neonates, and remain unchanged early after successful operation. Surgical correction does not resolve inborn pathology of the prestenotic aortic vascular bed.

Myocardial Blood Flow and Flow Reserve After Coronary Reimplantation in Patients After Arterial Switch and Ross Operation

BackgroundCoronary reimplantation is used in therapy for congenital heart disease, such as in the arterial switch (ASO) and Ross operations. The adequacy of myocardial perfusion may remain a matter of concern. The aim of the present study was to stratify the effect of coronary reimplantation on myocardial perfusion and to highlight the clinical relevance of any attenuation in myocardial perfusion. Methods and ResultsA total of 21 children with transposition of the great arteries at a mean interval of 11.2±2.9 years after ASO and 9 adolescents at a mean interval of 4.2±2.1 years after the Ross procedure were investigated. All patients were asymptomatic and had a normal exercise capacity. On stress echocardiography, 2 of the ASO patients had dyskinetic areas within the left ventricular myocardium, and 5 had adenosine-induced perfusion defects on positron emission tomography. No coronary obstruction was detected on coronary angiography in any patient, but a common finding was right coronary dominance and a small caliber of the distal part of the left anterior descending artery. Coronary flow reserve (CFR) was significantly reduced in all patients after ASO when compared with 10 normal healthy volunteers (age, 25.6±5.3 years). CFR was normal in the 9 patients who had the Ross operation (age, 19.2±7.6 years); exercise-induced perfusion defects were not detected in the Ross patients. ConclusionsChildren after ASO are asymptomatic, without clinical signs of coronary dysfunction. In contrast to patients who had the Ross operation, stress-induced perfusion defects and an attenuated CFR were documented. The prognostic implications of these findings and the clinical consequences are unclear; nevertheless, close clinical follow-up of ASO patients is mandatory.

Myocardial Perfusion and Coronary Flow Reserve Assessed by Positron Emission Tomography in Patients after Fontan-like Operations

Ventricular dysfunction in patients after Fontan-like operations (FLOs) is a serious complication that might contribute to poor long-term results. Ischemic heart disease will have debilitating consequences on a Fontan heart. Ten patients (15.8 ± 5.01 years) after FLO had transesophageal echocardiography and cardiac catheterization 9.3 ± 4.2 years after surgery. Myocardial perfusion was assessed by NH3-positron emission tomography (rest/adenosine) and compared with that of 10 healthy adults (26.1 ± 6.3 years). Ventricular function was normal in 4 and reduced in 6 patients; end systolic and end diastolic meridional wall stress was significantly elevated in the FLO group. Coronary angiography revealed no stenosis of the coronaries. Compared to normals, myocardial blood flow (MBF) at rest was higher in the FLO group (0.99 ± 0.25 vs 0.77 ± 0.17 ml/g/min, p < 0.05), whereas MBF after vasodilatation (2.12 ± 0.78 vs 3.10 ± 0.85 ml/g/min, p < 0.05) and coronary flow reserve (CFR) was reduced (2.5 ± 0.88 vs 4.1 ± 1.01, p < 0.05), especially in those with impaired ventricular function. Coronary vascular resistance after vasodilatation was elevated in the FLO group (38.2 ± 17.4 vs 24.5 ± 8.3 mmHg/ml/g/min, p < 0.05). Altered MBF, increased meridional wall stress, and impaired CFR are common findings in FLO. Attenuated CFR and reduced ventricular function are significantly correlated and may be risk factors for the long-term outcome.

Reduced contractile reserve of the systemic right ventricle under Dobutamine stress is associated with increased brain natriuretic peptide levels in patients with complete transposition after atrial repair

AIMS To compare B-type natriuretic peptide (BNP) levels with response of systemic right ventricular function to Dobutamine stress. METHODS AND RESULTS Sixteen patients aged 25.6 +/- 3.7 years (eight each after Senning or Mustard repair of complete transposition) were studied. Transoesophageal imaging was performed in the catheterization laboratory under general anaesthesia before and at the end of a 10 min infusion of 5 microg/kg/min of Dobutamine. The BNP levels were measured at rest. Myocardial Doppler data were acquired before and at peak stress in a four-chamber view. The BNP (pg/mL) values of 67.3 +/- 47.5 (14-189) were elevated. There was no correlation between BNP and IVA, strain, or systolic and diastolic velocities at rest. Dobutamine stress led to a significant increase in IVA, s-velocity, and strain but no significant change in e-velocity. A correlation was found between increase in IVA under Dobutamine and BNP levels (r = 0.57, P < 0.02). CONCLUSION Elevated BNP levels correlate with response of systolic right ventricular function assessed by IVA to Dobutamine stress.

Periventricular closure of a perimembranous VSD: treatment option in selected patients.

Ventricular septal defects (VSDs) are a common congenital heart disease. Usually, surgical repair with cardiopulmonary bypass (CPB) is the treatment of choice, whereas percutaneous techniques have technical limitations, predominantly a mismatch of catheter size and body weight. A 7-year-old girl underwent periventricular closure of a perimembranous VSD on the beating heart. Echocardiography guided implantation through a minimally invasive sternotomy was uneventful. The described approach adds favorably to the current practice avoiding the use of CPB. Cosmetic aspect and rapid early postoperative recovery are convincing.

Clinical, echocardiographic and histopathologic findings in nine patients with surgically explanted ASD/PFO devices: Do we know enough about the healing process in humans?

BACKGROUND Atrial septal defects (ASD) and persistent foramen ovale (PFO) are managed in increasing numbers by catheter interventions as an attractive alternative to surgery. Early complications have been described in clinical series whereas late complications are rare. No series are reported with clinical, echocardiographic and histological data. METHODS AND RESULTS We collected clinical, echocardiographic, and histolological data of nine patients with surgically explanted devices. Occlusion devices were explanted after a mean interval of 3.4 ± 2.4 years (range 0.9-8.3). Indications were recurrent thromboembolic events in five, residual shunt/dislocation in three, and growing mass on echocardiography despite oral anticoagulation in one patient. Two patients suffered potentially live threatening events due to coronary embolism. One of them had to be resuscitated due to ventricular fibrillation. Histologically, residues of superficial thrombus formation could be demonstrated in two of the devices. In another patient, hyperplastic tissue formation was related to a local inflammatory process but not to a thrombus as suspected by echocardiography. CONCLUSION Late complications after device implantation may occur up to 8 years after device implantation and may be potentially live threatening. Echocardiographic controls should be prolonged beyond the first year after implantation and every explanted device should be histologically worked up in an experienced center. Up to now, the mechanisms of late thrombogenesis are not fully understood.

Improvements in exercise performance after surgery for Ebstein anomaly

OBJECTIVE The purpose of this longitudinal study was to assess improvements in exercise performance and quality of life in patients with Ebstein anomaly after surgical intervention. METHODS In 21 patients with Ebstein anomaly (between 6 and 59 years of age; 16 female, 5 male) who underwent surgery for tricuspid regurgitation and, if present, closure of an interatrial shunt, a cardiopulmonary exercise test and a quality-of-life assessment by the Medical Outcomes Study 36 item short form was performed prior to and 6 to 18 months after surgery. RESULTS After surgery, peak oxygen uptake increased from 68.4% of predicted to 77.3% of predicted (P = .009), and ventilatory efficiency (VE/VCO(2) slope) improved from 32.5 to 29.3 (P = .001). In 14 patients with additional interatrial shunt closure, oxygen saturation improved from 95% to 99% at rest (P = .003) and from 88% to 99% under peak exercise (P = .003). Improvements in VE/VCO(2) slope were similar in patients who had undergone primary surgery (P = .005) or reoperation (P = .018). Increase in exercise capacity was also similar in both groups but failed significance in both (primary surgery, P = .064; reoperation, P = .063). There was no difference between tricuspid valve repair and replacement in the short-term follow-up. Self-estimated quality of life was fairly good prior to and after surgery. Only in the single question about health transition at follow-up did the patients confirm an improved situation after surgery. CONCLUSIONS Patients with Ebstein anomaly and severe tricuspid regurgitation draw clinical benefit from surgical intervention as measured on exercise testing. This holds true for primary surgery and for reoperation.

Tricuspid valve surgery improves cardiac output and exercise performance in patients with Ebstein's anomaly

BACKGROUND Clinical, hemodynamic and functional effects of tricuspid valve surgery in patients with Ebsteins anomaly are not well understood. METHODS Sixteen patients (median age of 27.7 years) were examined before and eight months after surgery by means of echocardiography, cardiovascular magnetic resonance (CMR) and cardiopulmonary exercise testing. RESULTS Peak work load (1.87 to 2.0W/kg; p=0.026), maximum oxygen uptake (21 to 22 ml/kg/min; p=0.034) as well as cardiac output (2.7 to 2.9l/min/m(2); p=0.035) increased postoperatively. The reduction of tricuspid regurgitation led to a higher pulmonary stroke volume (29 to 42ml/m(2), p=0.005) and augmented the left ventricular (LV) volume (55 to 63ml/min/m(2); p=0.001) with a trend to better ejection fraction (61 to 64%; p=0.083). Right ventricular (RV) volume index (124 to 108ml/m2; p=0.034) and ejection fraction (50 to 42%; p=0.036) decreased on CMR. Echocardiographic measurements of RV function also decreased (tricuspid annular plane systolic excursion 2.3 to 1.7; p=0.002; isovolumic acceleration 0.98 to 0.65; p=0.004; and 2-d longitudinal global strain -19.3 to -16.25; p=0.006). CONCLUSION Tricuspid valve surgery improves exercise capacity in patients with Ebsteins anomaly. The reduction of tricuspid regurgitation decreases the volume of the right ventricle and increases pulmonary antegrade flow. As a result LV volume and cardiac output increase. This hemodynamic benefit occurs despite the preload dependent reduction in RV volume and ejection fraction.

Non-volumetric echocardiographic indices and qualitative assessment of right ventricular systolic function in Ebstein's anomaly: comparison with CMR-derived ejection fraction in 49 patients

AIMS Ebsteins anomaly (EA) is often associated with right ventricular (RV) dysfunction. Data on echocardiographic quantification of RV function are, however, rare. The aim of this study was to determine how non-volumetric echocardiographic indices and qualitative assessment of global systolic RV function correlate with cardiovascular magnetic resonance (CMR)-derived RV ejection fraction (EF). METHODS AND RESULTS We compared six echocardiographic indices and qualitative assessment of RV function with the gold standard CMR. A total of 49 unoperated patients with EA and a mean age of 32 ± 18 years were examined. Tricuspid annular plane systolic excursion, tissue Doppler myocardial velocities (peak S and IVA) and 2D strain and strain rate measures for the RV were compared with CMR-derived EF. Only 2D global longitudinal strain (2D-GLS), out of the six parameters investigated, showed a weak, although statistically significant correlation with CMR-derived RVEF (R = -0.4, P = 0.01). Using a cut-off value of -20.15, 2D-GLS sensitivity (77%) and specificity (46%) in detecting patients with a CMR-derived EF of <50% were comparable with qualitative assessment (sensitivity 77%, specificity 45%). CONCLUSION Overall echocardiographic parameters of RV function correlate poorly with CMR-derived EF in patients with EA. Only 2D global longitudinal RV strain correlated weakly with CMR-derived RVEF. However, the sensitivity and specificity for detecting RV dysfunction using 2D strain imaging were comparable with qualitative RV functional assessment.

Da Silva's cone repair for Ebstein's anomaly: effect on right ventricular size and function

OBJECTIVES Da Silvas cone repair is a novel technique for surgical reconstruction of the tricuspid valve and the right ventricle (RV) in Ebsteins anomaly. The technique consists of extensive leaflet mobilization, longitudinal plication of the atrialized ventricle and cone-shaped reconstruction of the tricuspid valve, allowing for leaflet-to-leaflet coaptation. We evaluated the influence of Da Silvas cone repair on tricuspid competency, right ventricular size and function. METHODS From February 2010 until July 2013, 20 patients (median age 30.0 years, range 6.6-68.3 years) underwent Da Silvas cone repair. A 4- to 6-mm interatrial communication was left in all patients. Echocardiographic studies and magnetic resonance imaging (MRI) before and after the repair were evaluated. RESULTS Median follow-up was 11 (0.5-36) months. There were 2 early deaths and no late death. Echocardiography at follow-up revealed mild or absent tricuspid regurgitation in 16 patients. Two patients showed moderate tricuspid insufficiency. MRI studies showed that the mean functional RV end-diastolic volume decreased after surgery (pre 334 [135-656] ml; post 175 [115-404] ml, P < 0.001). The mean RV ejection fraction decreased (pre 47 ± 10%; post 35 ± 13%, P = 0.001), and the mean antegrade net stroke volume of the RV increased (pre 65 ± 28 ml; post 75 ± 30 ml, P = 0.057). CONCLUSIONS Da Silvas cone repair for Ebsteins anomaly creates excellent valve function in all patients. Consecutively, the size of the RV decreases and the antegrade net stroke volume increases 6 months after the operation.