Rudolf Mair

Right ventricular to pulmonary artery conduit instead of modified Blalock-Taussig shunt improves postoperative hemodynamics in newborns after the norwood operation

OBJECTIVE Perioperative mortality, prolonged postoperative recovery after the Norwood procedure, and mortality between stage I and stage II might be related to shunt physiology. A right ventricular to pulmonary artery conduit offers a banded physiology in contrast to a Blalock-Taussig shunt. The purpose of this study was to assess the hemodynamic differences and their consequences in the postoperative course between Norwood patients with a Blalock-Taussig shunt and those with a right ventricular to pulmonary artery conduit. METHODS From October 1999 until May 2002, 32 unselected consecutive patients underwent a Norwood procedure at the General Hospital Linz. The first 18 patients received a Blalock-Taussig shunt. In the remaining 14 patients we performed a right ventricular to pulmonary artery conduit. Both groups were compared. RESULTS The diastolic blood pressure was significantly higher in the right ventricular to pulmonary artery conduit group (P <.001). Despite a higher FIO(2), PO(2) levels tended to be lower in the first 5 postoperative days. At the age of 3 months, catheterization laboratory data showed a lower Qp/Qs ratio in the same group (0.86 [0.78; 1] versus 1.55 [1.15; 1.6]; P =.005) and a higher dp/dt (955 [773; 1110] vs 776 [615; 907]; P =.018). (Descriptive data reflect medians and quartiles [in brackets].) Hospital survival was 72% in the Blalock-Taussig shunt group versus 93% in the right ventricular to pulmonary artery conduit group. Mortality between stage I and stage II was 23% in the Blalock-Taussig shunt group versus 0% in the right ventricular to pulmonary artery conduit group. CONCLUSIONS A higher diastolic blood pressure and a lower Qp/Qs ratio were associated with a more stable and efficient circulation in patients with a right ventricular to pulmonary artery conduit. More intensive ventilatory support was necessary during the first postoperative days. We did not note any adverse effects of the ventriculotomy on ventricular performance.

Early primary repair of tetralogy of fallot in neonates and infants less than four months of age.

BACKGROUND The ideal age for correction of tetralogy of Fallot is still under discussion. The aim of this study was to analyze morbidity and mortality in patients who underwent early primary repair of tetralogy of Fallot at the age of less than 4 months and to assess whether neonates, who needed early repair within the first 4 weeks of life, faced an increased risk. METHODS From 1995 to 2006, 90 consecutive patients with tetralogy of Fallot and pulmonary stenosis underwent early primary repair. Patient charts were analyzed retrospectively for two groups: group A, 25 neonates younger than 28 days who needed early operation owing to duct-dependent pulmonary circulation or severe hypoxemia; and group B, 65 infants younger than 4 months of age who underwent elective early repair. RESULTS There was no 30-day mortality; late mortality was 2% after a median follow-up time of 4.7 years. Seven of 88 patients (8%) needed reoperation and twelve of 88 patients (14%) needed reintervention. Groups A and B did not differ significantly in terms of intensive care unit stay, days of mechanical ventilation, overall hospital stay, major or minor complications, or reoperation. Significant differences were found in a more frequent use of a transannular patch (p = 0.045) and more reinterventions (p = 0.046) in group A. CONCLUSIONS Early primary repair of tetralogy of Fallot can be performed safely and effectively in infants younger than 4 months of age and even in neonates younger than 28 days with duct-dependent pulmonary circulation or severe hypoxemia.

Mycotic aneurysms of the thoracic aorta

Between February 1982 and December 1992 we operated on five patients (three men, two women; aged 40 to 70 years) with mycotic aneurysms of the thoracic aorta. One patient had an aneurysm of the ascending aorta, once the aortic arch and in three cases the descending thoracic aorta were involved. In four of the five patients, excision of the aneurysm and in situ reconstruction of the aorta with a Dacron graft was performed, one patient required a Dacron graft repair and aortic valve replacement. We employed deep hypothermia with circulatory arrest (2), extracorporeal circulation (1), an axillofemoral shunt (1) and a centrifugal pump (1) for cerebral and spinal cord protection. One patient died 4 months postoperatively, the other four patients were without recurrent graft infection and are free of symptoms between 20 months and 5 years postoperatively.

Bilateral Nephrectomy: the Best, but Often Overlooked, Treatment for Refractory Hypertension in Hemodialysis Patients

Bilateral nephrectomy for treatment of refractory hypertension in chronic hemodialyzed patients has been infrequently carried out. We analyzed the benefits of this operation on blood pressure, clinical state, drug treatment, and quality of life. In 10 hemodialyzed patients with refractory hypertension, systolic (SBP) and diastolic (DBP) blood pressure were measured 1 month before nephrectomy bilateral and 3, 6, 9, and 12 months after. In addition, the use of antihypertensive drugs before and after surgery was evaluated. Four patients had SBP and DBP values characteristic of malignant hypertension. In all 10 patients hypertension responded neither to reduction of plasma volume by ultrafiltration nor to multiple antihypertensive drug therapy. Hypertensive crises were associated with cerebral hemorrhage in two patients, severe encephalopathy with persistent neural dysfunction in one patient, and encephalopathy and diplopia in another. Three months after bilateral nephrectomy blood pressure decreased significantly (P < .005) and was normal in nine patients. In one noncompliant patient with intradialytic body weight increases of nearly 10%, blood pressure was still elevated. Malignant or drug-resistant hypertension with hypertensive crises is an indication for bilateral nephrectomy. The clinical state and quality of life improved in all patients in the present study and antihypertensive treatment is no longer necessary.

Levosimendan versus milrinone in neonates and infants after corrective open-heart surgery: a pilot study.

Objective: Low cardiac output syndrome commonly complicates the postoperative course after open-heart surgery in children. To prevent low cardiac output syndrome, prophylactic administration of milrinone after cardiopulmonary bypass is commonly used in small children. The aim of this study was to compare the effect of prophylactically administered levosimendan and milrinone on cardiac index in neonates and infants after corrective open-heart surgery. Design: Prospective, single-center, double-blind, randomized pilot study. Setting: Tertiary care center, postoperative pediatric cardiac intensive care unit. Patients: After written informed consent, 40 infants undergoing corrective open-heart surgery were included. Interventions: At weaning from cardiopulmonary bypass, either a 24-hr infusion of 0.1 &mgr;g/kg/min levosimendan or of 0.5 &mgr;g/kg/min milrinone were administered. Cardiac output was evaluated at 2, 6, 9, 12, 18, 24, and 48 hrs after cardiopulmonary bypass using a transesophageal Doppler technique (Cardio-QP, Deltex Medical, Chichester, UK). Cardiac index was calculated from cardiac output and the patients’ respective body surface area. Results: Intention-to-treat data of 39 patients (19 in the levosimendan and 20 in the milrinone group) were analyzed using analysis of variance for repeated measurements for statistics. Analysis of variance revealed for both, cardiac index and cardiac output, similar results with no significant differences of the factors group and time. A significant interaction for cardiac output (p = .005) and cardiac index (p = .007) was found, which indicates different time courses of cardiac index in the two groups. Both drugs were well tolerated; no death or serious adverse event occurred. Conclusions: In our small study, postoperative cardiac index over time was similar in patients with prophylactically administered levosimendan and patients with prophylactically given milrinone. We observed an increase in cardiac output and cardiac index over time in the levosimendan group, whereas cardiac output and cardiac index remained stable in the milrinone group. This pilot study has primarily served to obtain experience using the new drug levosimendan in neonates and infants and to initiate further multicenter trials in pediatric patients.

Use of levosimendan, a new inodilator, for postoperative myocardial stunning in a premature neonate.

Objective: To first report the successful use of the new inodilator levosimendan in a premature infant with congestive heart failure (CHF) following cardiac surgery. Although the calcium sensitizer levosimendan improves hemodynamics in adults with CHF, no data are available on the use of levosimendan in premature infants with CHF. Design: Single case report. Setting: Twenty-bed postoperative adult and pediatric cardiac intensive care unit. Patient: A 32 wks gestational age, 1525-g premature male twin with transposition of the great arteries. Interventions: The patient underwent arterial switch operation. Measurements and Main Results: Immediately after operation, the patient developed signs of low cardiac output syndrome. Mixed venous saturation was 56%, serum lactate increased to 14.8 mmol/L, systolic arterial pressure was 40 mm Hg, left atrial pressure was 24 mm Hg, and echocardiography showed reduced left ventricular function with a fractional shortening of 10%. There were no signs of reduced coronary perfusion. Milrinone, dobutamine, and epinephrine did not improve hemodynamics. Levosimendan was initiated at a dose of 0.05 &mgr;g·kg−1·min−1, increased to 0.1 &mgr;g·kg−1·min−1, and continuously infused for 24 hrs. Within 6 hrs after starting the levosimendan infusion, left atrial pressure decreased to 7 mm Hg and systolic arterial pressure increased to 60 mm Hg; within 24 hrs after initiation serum lactate level normalized to 1.7 mmol/L and mixed venous saturation increased to 81%. Echocardiography revealed improvement of left ventricular function with a fractional shortening of 25%. No side effects were recognized during administration of levosimendan. Conclusions: In this premature neonate with postoperative low cardiac output syndrome due to failing myocardial function, levosimendan was a potent inotropic agent.

Open-heart surgery in premature and low-birth-weight infants — a single-centre experience

OBJECTIVE Because of their poor clinical status, infants may require surgery for congenital heart disease regardless of weight or prematurity. This retrospective review describes a single-centre experience with open-heart surgery in low-weight infants. METHODS From November 1997 to December 2006, 411 open-heart surgery procedures were performed in neonates. This included 46 consecutive infants weighing less than 2500 g, who underwent cardiopulmonary bypass for correction of congenital heart defects (n=34) or Norwood stage I palliation of hypoplastic left heart syndrome (HLHS) (n=12). In the low-weight group were 23 males and 23 females with a median age of 10 days and a median weight of 2.26 kg (range: 1.28-2.49 kg). RESULTS Early mortality was 8.2% in patients weighing more than 2.5 kg and 13% in the low-weight group. Within the low-weight group, weight at surgery, history of prematurity and prevalence of additional extracardiac malformations did not influence early mortality. At a median follow-up time of 32 months overall mortality was 21%. Thirty-four patients had a neurological follow-up examination 30 months postoperatively. Of the 34 survivors, 11 showed neurological deficits. CONCLUSIONS In our patient population, early mortality was higher for infants weighing less than 2.5 kg. However, within the low-weight group, lower weight at surgery or history of prematurity was not associated with a higher mortality or bad neurological outcome.

Aortic valve replacement: Is the stentless xenograft an alternative to the homograft? early results of a randomized study

From November 1992 to October 1993 we randomized 101 patients over 60 years of age undergoing elective aortic valve replacement, with or without concomitant coronary artery bypass grafting, to receive either a cryopreserved aortic or pulmonary homograft (n = 38) or a stentless porcine aortic valve xenograft (Edwards Prima 2500) (n = 63). The majority of all valves (92%) were inserted freehand in the subcoronary position. Six homografts (16%) were implanted as a free-root replacement and two xenografts (3%) were used as a mini root. There were four in-hospital deaths (4%), three in the homograft group and one in the xenograft group (homograft, 7.9% versus xenograft, 1.6%; p = not significant). Forty-one patients were followed at 3- to 6-month intervals for 9 +/- 2 months (3 to 14 months) and valve pathology was assessed routinely by means of color flow Doppler echocardiography. Two patients in the homograft group developed new aortic insufficiency grade II; all others remained with trivial or no valve incompetence. The mean gradient remained unchanged to immediate postoperative measurements (homograft, 5 +/- 1 mm Hg versus xenograft, 11 +/- 4 mm Hg; p < 0.001). Despite a slightly higher transvalvular gradient, xenografts achieved excellent initial results when compared to homografts. Ease of implantation and freedom from thromboembolism indicate that xenografts can be an acceptable alternative to homografts, particularly in older patients with small aortic annuli. Long-term studies assessing the durability of the xenograft are necessary for final evaluation.

Early and mid-term outcome of the arterial switch operation in 114 consecutive patients : A single centre experience.

BackgroundThe arterial switch operation (ASO) has become the treatment of choice in patients with simple or complex transposition of the great arteries (TGA). The purpose of this study was to assess early and mid-term outcome after ASO in a single centre.Patients and methodsBetween 1995 and December 2005, 114 consecutive patients underwent an ASO at our institution, performed by one single surgeon. Patients charts, surgical reports and echocardiograms were retrospectively reviewed. Patients were analyzed in 3 different groups: Group I consisted of 77 neonates with TGA and intact ventricular septum, group II of 13 patients with TGA and ventricular septal defect which had to be closed surgically and group III of 24 patients with various forms of TGA in a complex setting. The patient’s median weight was 3.23 kg (1.65–8.30). Twenty-five neonates were born preterm, 18 were diagnosed prenatally. Median follow-up time was 20.7 months (0.3–128.6).ResultsThe thirty day mortality was 1.75% (2/114), late mortality 0.88% (1/112) accounting for an overall mortality of 2.63%. There was only one early coronary event and so far no late events. Ten of 111 survivors required reoperation, all but 1 from group III. Prevalence of supravalvular pulmonary stenosis was 4.7%. Freedom from reoperation at 5 years of follow-up time was 87.5%. One patient required permanent pacing, no other late arrhythmias occurred. In our series the only risk factor for increased mortality and morbidity was a body weight of less than 2500 g at the time of operation. No better outcome could be demonstrated in the prenatally diagnosed patients.ConclusionThe ASO can be performed safely and with low mortality and morbidity even in patients with complex TGA. Follow-up of these patients is required to detect residual problems like supravalvular pulmonary stenosis, coronary problems, arrhythmias and aortic valve dysfunction.

Aortic valve replacement: is the stentless xenograft an alternative to the homograft? midterm results

BACKGROUND This study was performed to assess the midterm clinical results after aortic valve replacement (AVR) with stentless xenograft (SX) compared with cryopreserved aortic or pulmonary homografts (HX). METHODS In 139 patients (<60 years) undergoing elective AVR, 59 HX and 80 SX were inserted. All patients were followed clinically and by color flow Doppler echocardiography for 45+/-12 months (range 31-58 months). RESULTS There were 5 in-hospital deaths (3.5%): 4 HX and 1 SX (p = NS). The mean gradient was 6+/-2 mm Hg in HX versus 13+/-6 mm Hg in SX (p<0.001) and remained unchanged during follow-up. Actuarial survival (HX 77%, SX 80%), freedom from endocarditis (HX 91%, SX 99%), freedom from thromboembolic events (HX 98%, SX 90%), and freedom from reoperation (HX 98%, SX 100%) were comparable between groups after 58 months. CONCLUSIONS Despite slightly higher transvalvular gradients, the stentless aortic valve achieved excellent midterm results, when compared with homografts.