Aortic valve replacement in pediatric patients: 30 years single center experience

Background

The choice of aortic valve replacement needs to be decided in an interdisciplinary approach and together with the patients and their families regarding the need for re-operation and risks accompanying anticoagulation. We report long-term outcomes after different AVR options.

Methods

A chart review of patients aged < 18 years at time of surgery, who had undergone AVR from May 1985 until April 2020 was conducted. Contraindications for Ross procedure, which is performed since 1991 at the center were reviewed in the observed non-Ross AVR cohort. The study endpoints were compared between the mechanical AVR and the biological AVR cohort.

Results

From May 1985 to April 2020 fifty-five patients received sixty AVRs: 33 mechanical AVRs and 27 biological AVRs. In over half of the fifty-three AVRs performed after 1991 (58.5%; 31/53) a contraindication for Ross procedure was present. Early mortality was 5% (3/60). All early deaths occurred in patients aged < 1 year at time of surgery. Two late deaths occurred and survival was 94.5% ± 3.1% at 10 years and 86.4% ± 6.2% at 30 years. Freedom from aortic valve re-operation was higher (p < 0.001) in the mechanical AVR than in the biological AVR cohort with 95.2% ± 4.6% and 33.6% ± 13.4% freedom from re-operation at 10 years respectively.

Conclusions

Re-operation was less frequent in the mechanical AVR cohort than in the biological AVR cohort. For mechanical AVR, the risk for thromboembolic and bleeding events was considerable with a composite linearized event rate per valve-year of 3.2%.

Long-term outcomes after the paediatric Ross and Ross-Konno procedures

OBJECTIVES

The Ross procedure is an attractive option for the management of aortic valve disease in paediatric patients. We reviewed our experience with the paediatric Ross procedure to determine survival and freedom from reoperation in the third decade after surgery.

METHODS

We reviewed the data of 124 paediatric patients [71% male, median age at time of surgery 11.1 years (interquartile range 6-14.8 years); 63.7% bicuspid aortic valve], who underwent the Ross procedure at 2 tertiary centres from April 1991 to April 2020. The Ross-Konno procedures were performed on 14 (11.3%) patients. Deaths were cross-checked with the national health insurance database, and survival status was available for 96.8% of the patients. The median follow-up time was 12.1 years (interquartile range 3-18 years).

RESULTS

There were 3 early and 6 late deaths. All early deaths occurred in patients aged <1 year at the time of surgery. The 25-year survival was 90.3%. Actuarial freedom from reoperation (linearized rates in parentheses) was as follows: Autograft reoperation was 90.8% (0.48%/patient-year) and right ventricular outflow tract (RVOT) reoperation was 67% (2.07%/patient year) at 25 years. The univariable Cox-proportional hazard analysis revealed younger age at time of surgery (P < 0.001), smaller implanted valve size (P < 0.001) and the use of a xenograft rather than a homograft (P < 0.001) as predictors of RVOT reoperation. At multivariable Cox-proportional hazard analysis, only age was an independent risk factor for RVOT reoperation (P = 0.041).

CONCLUSIONS

The Ross and the Ross-Konno procedures are associated with good outcomes in paediatric patients. Reoperation of the RVOT is frequent and associated with younger age.

The oxygen dissociation curve: quantifying the shift

An oxyhaemoglobin dissociation curve (ODC) quantifies the most important function of red blood cells and that is the affinity for oxygen and its delivery to the tissues. Oxygen affinity for haemoglobin plays a critical role in the delivery of oxygen to the tissues and is changed by shifting to the left or right. A shift to the left implies an increased oxygen affinity and, hence, tighter binding due to the higher oxygen saturation in relation to the pO2.On the other hand, a shift to the right corresponds to a decreased oxygen affinity and easier release of oxygen to the tissues. It is well known that the ODC shifts in response to changes in pH, pCO2 and 2,3 diphosphoglycerate. However, how much the ODC shifts has never been quantified. Arterial and venous blood gases were taken during cardiopulmonary bypass and two indices were used to quantify the shift of the ODC; the p50 shift and the SO2 difference. Arterial blood shifted to the right by 49-0.1 mmHg at a pH of 7.24 and shifted to the left by -3.59-0.05 mmHg at a pH of 7.51. The change in arterial saturation was minimal, rising by 0.8% and dropping by -5% and did not correlate to p50 shifting and changes in pH, but demonstrated changes dependent on the concentration of dyshaemoglobins. The venous blood exhibited a greater range of p50 shifting at each pH value. At a pH of 7.24, the p50 shifted to the right by 4.89-2 mmHg and at a pH of 7.51 the p50 shifted to the left by -4±1.8 mmHg. Unlike the arterial blood, the change in saturation correlated well to p50 shifting. It is shown here for the first time how much the curve shifts with changes in pH and how this may be used to evaluate treatment strategies.

Midterm results of aortic valve replacement with cryopreserved homografts

OBJECTIVE

The aim of this study was to analyze the midterm clinical results of aortic valve replacement with cryopreserved homografts.

MATERIALS AND METHODS

Aortic valve replacement was performed in 40 patients with cryopreserved homograft. The indications were aortic valve endocarditis in 20 patients (50%), truncus arteriosus in 6 patients (15%), and re-stenosis or regurtitation after aortic valve reconstruction in 14 (35%) patients. The valve sizes ranged from 10 to 27mm. A full root replacement technique was used for homograft replacement in all patients.

RESULTS

The 30-day postoperative mortality rate was 12.5% (5 patients). There were four late deaths. Only one of them was related to cardiac events. Overall mortality was 22.5%. Thirty-three patients were followed up for 67±26 months. Two patients needed reoperation due to aortic aneurysm caused by endocarditis. The mean transvalvular gradient significantly decreased after valve replacement (p<0.003). The last follow up showed that the 27 (82%) patients had a normal left ventricular function.

CONCLUSION

Cryopreserved homografts are safe alternatives to mechanical valves that can be used when there are proper indications. Although it has a high perioperative mortality rate, cryopreserved homograft implantation is an alternative for valve replacement, particularly in younger patients and for complex surgical problems such as endocarditis that must be minimalized.

Predictors of outcome of non-ischemic mitral valve surgery

BACKGROUND

Data on the risk stratification of patients undergoing mitral valve (MV) surgery for non-ischemic mitral disease are sparse. The present study seeks to define them in a contemporary cohort.

METHODS

193 consecutive patients referred to non-ischemic MV surgery were prospectively studied. Baseline characteristics and the type of surgery were analyzed with regard to operative and late mortality as well as functional outcome.

RESULTS

129 patients underwent MV replacement and 64 MV repair. MV replacement patients presented with more symptoms (p = 0.010), higher EuroSCORE (6.1 versus 5.6; p=0.009), more frequently underwent additional valve surgery (7.8 versus 0%; p = 0.003) and were more frequently female (p=0.048). Operative mortality was 3.1%, two thirds of operative deaths had additional surgery of the tricuspid valve (p = 0.019). Patients were followed for 5.2 ± 2.7 years. 1-, 3-, 5- and 7-year survival rates were 93-, 91-, 82-, and 79% in MV replacement patients versus 100-, 98-, 96-, and 89% in patients with MV repair (p = 0.015). However, by multivariate logistic regression, overall mortality was determined by additional surgery of the tricuspid valve (p = 0.0103), multivessel coronary disease (p = 0.026), and age (p<0.0001), but not by the type of surgery (p=0.066). Furthermore, the type of surgery did not influence functional outcome (p = 0.515).

CONCLUSIONS

Apart from age and coronary artery disease the need for additional tricuspid valve surgery significantly determines the outcome of non-ischemic MV surgery. The type of operation appears less important when the need for additional valve surgery and co-morbidities like coronary artery disease are taken into consideration.

Moderate patient-prosthesis mismatch after valve replacement for severe aortic stenosis has no impact on short-term and long-term mortality

BACKGROUND

The importance of moderate patient-prosthesis mismatch (PPM) for the prognosis of patients who undergo aortic valve replacement is unclear.

METHODS

The presence of PPM was assessed in 361 consecutive patients undergoing valve replacement for isolated severe aortic stenosis and related to perioperative and postoperative mortality. Indexed effective orifice areas (EOAi) were estimated for each type and size of prosthesis.

RESULTS

Using the previously proposed cut-off of EOAi <or=0.8 cm(2)/m(2), PPM was present in 54% of patients. Patients were followed for 4.1 (2.0) years. Survival tended to be slightly, but insignificantly, worse in the group with PPM (1-year, 3-year and 5-year survival 89%, 86% and 76% vs 92%, 88% and 82%; p = 0.21). However, patients with PPM were also older (p<0.0001), more often female (p<0.0001), more symptomatic (p = 0.001), more often had coronary artery disease (p = 0.04), triple vessel disease (p = 0.03) and hypertension (p = 0.01) and presented with a higher EuroSCORE (p<0.0001). By multivariate analysis only EuroSCORE and diabetes but not PPM were independent predictors of survival.

CONCLUSIONS

Moderate PPM is a frequent finding after aortic valve replacement. In our patient population it had no impact on short-term and long-term survival. It may therefore not be justified to recommend complex surgical interventions to avoid moderate PPM in patients undergoing aortic valve replacement for isolated severe aortic stenosis.

Role of amiodarone on the systemic inflammatory response induced by cardiac surgery: proinflammatory actions

PURPOSE

Amiodarone (AMIO), a widely used anti-arrhythmic drug, has been shown to reduce the incidence of atrial fibrillation after cardiac surgery and also to exert immunomodulatory actions in vitro and proinflammatory effects in vivo. The present study investigated the immunomodulatory properties of AMIO in the inflammatory response induced by cardiac surgery with cardiopulmonary bypass (CPB).

METHODS

In this double-blind, placebo-controlled trial, 20 patients undergoing elective coronary artery bypass graft were randomized to receive placebo or AMIO 600 mg day(-1) orally for seven days before surgery and 45 mg hr(-1) intravenously for 48 hr postoperatively. Plasma levels of the proinflammatory markers C-reactive protein (CRP), fibrinogen (FBG), tumour necrosis factor (TNF)-alpha, interleukin (IL)-6 and monocyte chemoattractant protein (MCP)-1, and the antiinflammatory marker IL-10, were compared before and after surgery.

RESULTS

Ninety-six hours after start of surgery, plasma levels of FBG had more than doubled (2.2 +/- 0.5-fold increase, P < 0.0001). Overall, FBG formation was significantly increased in the AMIO group (P = 0.048). Monocyte chemoattractant protein 1 secretion transiently increased four hours after start of surgery (6.6 +/- 4.5-fold increase) but rapidly declined thereafter, (P < 0.0001). There was a trend toward higher MCP-1 plasma concentrations in the AMIO group (P = 0.13). The plasma levels of CRP, TNF-alpha, IL-6 and Il-10 changed significantly over time, but were not altered by AMIO treatment.

CONCLUSION

In the inflammatory response induced by cardiac surgery with CPB, our data suggest that AMIO treatment is associated with a selective trend toward proinflammatory actions.

Recent trends in heart transplantation: the University of Vienna experience

Since the beginning of the University of Vienna Cardiac Transplant Program in 1984, 1086 heart transplant procedures have been performed through the end of 2007. One- and five-year survival has increased steadily over time (82% and 76%). Ten-year survival is 65%. Over the past 10 years our program has seen dramatic changes in patient selection, accepting now patients with more risk factors (Age, diabetes, elevated pulmonary resistance,..). Developments in immunosuppression have decreased incidence of infection, rejection and graft arteriosclerosis continuously. Our program continues to pursue novel strategies to improve the survival and quality of life of our heart transplant patients.

Vacuum assisted closure therapy for the treatment of sternal wound infections in neonates and small infants

Sternal wound infections occur with an incidence between 0.4 and 5% in the adult as well as the pediatric population. However, in contrast to the adults, established treatment options do not exist in the pediatric population. We evaluated our preliminary results with 3 neonates, respectively, small infants (mean age 20.3+/-6 days) who underwent vacuum assisted closure (VAC) therapy for the treatment of sternal wound infections with the intention to enable secondary closure and preservation of the sternal bone. The mean VAC duration was 11.3 days, ranging from 10 to 12 days. After three dressing changes (every 48 to 72 h) the infection resolved and a secondary closure was feasible in all three patients. Isolated specimens were Candida albicans, Staphylococcus aureus and MRSA, respectively. These preliminary results show that VAC therapy is a promising alternative to the current treatment options available to neonates. Especially, the preservation of the sternal bone which enables normal thoracic cage stability and growth, is a clear advantage over the currently used muscle flaps.

Vascular dysfunction after coarctation repair is related to the age at surgery

BACKGROUND

Despite repair of aortic coarctation, hypertension is frequent in adults and premature coronary and cerebrovascular disease remain of concern. Persistent impairment of arterial dilation has been suspected to contribute to abnormal blood pressure regulation. We tested the hypothesis that arterial reactivity is more likely to be impaired in patients corrected at older age.

METHODS

We studied changes in brachial artery diameter in response to reactive hyperemia (FMD) and to nitroglycerin (NMD) in 36 patients and 25 controls. Depending on their age at surgery, patients were divided in group A (surgery <9 years) and group B (surgery > or =9 years).

RESULTS

Cholesterol levels and percentage of smokers were similar in patients and controls, but 16 patients had arterial hypertension compared to none of the controls. Endothelium-dependent vasodilation, FMD, and endothelium-independent vasodilation, NMD, were significantly impaired in patients vs. controls (8.2+/-6.2% vs. 13.0+/-5.1%, p<0.001 and 12.9+/-8.0% vs. 18.8+/-9.2%, p<0.01, respectively), both, in hypertensives (8.3+/-6.0%, p<0.01 and 11.8+/-6.0%, p<0.05) and in normotensives (8.1+/-6.5% p<0.01 and 13.8+/-9.3%, p<0.05). However, FMD and NMD in patients of group A did not significantly differ from that in controls (10.0+/-6.7% n.s. and 15.0+/-7.6% n.s.), whereas they were lowest in patients of group B (5.5+/-4.3%, p<0.0001 and 9.6+/-7.7% p<0.001).

CONCLUSIONS

Persistent impairment of FMD and NMD after repair of coarctation is more likely to be present in patients corrected at older age. It may be an important contributor to abnormal blood pressure regulation and late morbidity and mortality.

The University of Vienna experience in heart transplantation

Since the University of Vienna Cardiac Transplant Program began in 1984, 892 heart transplant procedures have been performed through the end of 2001. One- and five-year survival has increased steadily over time to 80% and 75%, respectively, in the most recent cohort. Ten-year survival is 55%. Over the past 10 years our program has seen dramatic changes in patient selection, accepting now patients with more risk factors (age, diabetes, elevated pulmonary resistance,..). Developments in immunosuppression have decreased the incidence of infection, rejection and graft arteriosclerosis continuously. Our program continues to pursue novel strategies to improve the survival and quality of life of our heart transplant patients.

Early postoperative prediction of cerebral damage after pediatric cardiac surgery

BACKGROUND

Cerebral damage is a serious complication of pediatric cardiac surgery. Early prediction of actual risk can be useful in counseling of parents, and in early diagnosis and rehabilitation therapy. Also, if all children at risk could be identified therapeutic strategies to limit perioperative cerebral damage might be developed. The aim of this study is to create a mathematical model to predict risk of neurologic sequelae within 24 hours after surgery using simple and readily available clinical measurements.

METHODS

The hospital records of 534 children after cardiac surgery were reviewed. Variables examined were age at operation, diagnosis, use of cardiopulmonary bypass, arterial and central venous oxygen saturation, serum glucose, lactate and creatine kinase, mean arterial pressure, and body temperature. The endpoint for each study patient was the occurrence or lack of occurrence of seizures, movement or developmental disorders, cerebral hemorrhage, infarction, hydrocephalus, or marked cerebral atrophy. Univariate and multivariate regression analyses were used to evaluate the predictive power of the investigated factors as well as to create a predictive model.

RESULTS

In 6.26% of children symptoms of cerebral damage were found. Significant risk factors were age at surgery, more complex malformations, metabolic acidosis, and increased lactate (odds ratio: age, 0.882/yr [0.772-1.008]; complex malformations, 10.32 [1.32-80.28]; arterial pH more than 7.35 to 0.4 [0.18-0.89]; lactate -1.018 per mg/dL [1.006-1.03]).

CONCLUSIONS

It is possible to quantify the risk of appearance of symptoms of cerebral damage after cardiac surgery within 24 hours using simple and readily available clinical measurements.

Methemoglobin formation in children with congenital heart disease treated with inhaled nitric oxide after cardiac surgery

OBJECTIVE

Inhaled nitric oxide (NO) is used as a therapy of pulmonary hypertension in children after cardiac surgery. Hemoglobin binds to NO with great affinity and forms methemoglobin by oxidation in the erythrocyte. Once produced, methemoglobin is unable to transport and unload oxygen in the tissues. The amount of available hemoglobin in the body for oxygen transport is thereby reduced. Anemia, acidosis, respiratory compromise and cardiac disease may render patients more susceptible than expected for a given methemoglobin level. The goal of the present study was to review the cumulative effect of inhaled NO on methemoglobin formation in critically ill children. We therefore looked for methemoglobin levels in children with congenital heart disease after cardiac surgery who were treated with inhaled NO in a range of 5-40 ppm.

METHODS

We retrospectively reviewed the medical charts of 38 children with congenital heart disease after cardiac surgery. We extracted demographic data and physiological measurements at the following time points: (1) T0 = before starting inhaled NO therapy, (2) T1 = 24 h after the beginning of inhaled NO therapy, (3) T2 = half-time therapy, (4) T3 = end of therapy, (5) T4 = 24 h after finishing inhaled NO therapy.

RESULTS

The median duration of inhaled NO therapy was 5.5 days (interquartile range 6, range 2-29), NO concentrations at T1 and T2 were 16 ppm (10, 5-40) and 12.5 ppm (12.3, 2-40), respectively. The median cumulative dose of inhaled NO was 1699 ppm (2313, 193-7018). Methemoglobin levels increased moderately, but significantly, during therapy ( T0 vs T1 p<0.05 and T0 vs T2 p<0.001). The highest methemoglobin level measured was 3.9%. Methemoglobin levels correlated positively with the inhaled NO doses applied at T1 ( r(2)=0.8376; p<0.01) and at T2 ( r(2)=0.8945; p<0.01). At T1 the methemoglobin level correlated negatively with the T1 blood pH value. The overall mortality rate was 13.2% (5 of 38 study patients died). There was no significant difference in methemoglobin levels between survivors and non-survivors.

CONCLUSION

We conclude from our data that the use of inhaled NO therapy for children with congenital heart disease after cardiac surgery in the described range of 5-40 ppm, resulting in a maximum of 4% methemoglobin blood level, is feasible and safe. However, we recommend the use of the minimal effective dose of inhaled NO and continuous monitoring of methemoglobin levels, especially in cases of anemia or sepsis in critically ill children.

Cold water submersion and cardiac arrest in treatment of severe hypothermia with cardiopulmonary bypass

In the paediatric population, submersion injury with drowning or near-drowning represents a significant cause of morbidity and mortality. This study reviews retrospectively our own experiences and the literature on the use of cardiopulmonary bypass (CPB) to rewarm paediatric victims of cold water submersion who suffer severe hypothermia (<28 degrees C) and cardiac arrest (asystole or ventricular fibrillation). In addition to three children treated at our institution, nine other victims were found in the literature. In this cohort of 12 children aged between 2 and 12 years, there was a tendency to better outcome with lower core temperature at the beginning of extracorporeal circulation (mean temperature in nine survivors, 20 degrees C; in three non-survivors, 25.5 degrees C). The lowest temperature survived was 16 degrees C. Neither base excess, pH nor serum potassium levels were reliable prognostic factors. The lowest base excess in a survivor was -36.5 mmol/l, the lowest pH 6.29. We consider CPB as the method of choice for resuscitation and rewarming of children with severe accidental hypothermia and cardiac arrest (asystole or ventricular fibrillation). Compared with adults, children, especially smaller ones, require special consideration with regard to intravenous cannulation as drainage can be inadequate using femoral-femoral cannulation. In hypothermic children we advocate, therefore, emergency median sternotomy. Until more information regarding prognostic factors are available, children who are severely hypothermic and clinically dead after submersion in cold water--even if for an unknown length of time--should receive cardiopulmonary resuscitation (CPR) and be transported without delay to a facility with capabilities for CPB instituted via a median sternotomy.

Neonatal and pediatric extracorporeal membrane oxygenation using nonocclusive blood pumps: the Vienna experience

Neonatal and pediatric extracorporeal membrane oxygenation (ECMO) is carried out commonly using occlusive blood pumps. Centrifugal pumps provide simple and safe technology for transportation on ECMO. The assistence respiratoire extra corporelle (AREC) system enables single needle venovenous ECMO for infants. We report on our experience with neonatal and pediatric ECMO treatments using nonocclusive blood pumps. One-hundred forty-six ECMO treatments were performed for cardiac, neonatal, and pediatric indications in 54, 19, and 27% of cases. Centrifugal pumps were used in 99, and the AREC system in 42 cases. Hospital mortality was estimated retrospectively and influence of type of pump, type of ECMO belonging to indication group, and lactate at ECMO installation were estimated. Irreversible organ failure leading to ECMO termination was investigated within groups of indications. Survival (recent 50 ECMO treatments) was 80, 70, 43, and 30% after meconium aspiration syndrome, acute respiratory distress syndrome, cardiac surgery, and prolonged resuscitation. Lactate exceeding 100 mg/dl at ECMO installation predicted significantly worse outcome. Cerebral damage was the main reason for ECMO termination in all but persistent circulatory failure in the cardiac group. Myocardial recovery resulted in all except 2 cardiac cases. Nonocclusive blood pumps can be used safely in neonatal and pediatric ECMO. Early installation may improve outcome markedly. In cardiac cases results of surgery should be thoroughly investigated on the table before ECMO installation to prevent hopeless ECMO treatments.

Can hypocapnia reduce cerebral embolization during cardiopulmonary bypass?

BACKGROUND

Cerebral embolization is a major cause of central nervous dysfunction after cardiopulmonary bypass. Experimental studies demonstrate that reductions in arterial carbon dioxide tension (PaCO2) can reduce cerebral embolization during cardiopulmonary bypass. This study examined the effects of brief PaCO2 manipulations on cerebral embolization in patients undergoing cardiac valve procedures.

METHODS

Patients were prospectively randomized to either hypocapnia (PaCO2 = 30 to 32 mm Hg, n = 30) or normocapnia (PaCO2 = 40 to 42 mm Hg, n = 31) before aortic cross-clamp removal. With removal of the aortic cross-clamp embolic signals were recorded by transcranial Doppler ultrasonography for the next 15 minutes.

RESULTS

Despite significant differences in PaCO2, groups did not differ statistically in total cerebral emboli counts. The mean number of embolic events was 107 +/- 100 (median, 80) in the hypocapnic group and 135 +/- 115 (median, 96) in the normocapnic group, respectively (p = 0.315).

CONCLUSIONS

Due to the high between-patient variability in embolization, reductions in PaCO2 did not result in a statistically significant decrease in cerebral emboli. In contrast to experimental studies, the beneficial effect of hypocapnia on cerebral embolization could not be demonstrated in humans.

Growth of the pulmonary autograft after the Ross operation in childhood

OBJECTIVE

Excellent hemodynamic performance has been demonstrated after aortic valve replacement using the autologous pulmonary valve as described by D. Ross. However, in the pediatric population there is concern in regard to growth of the autograft and late dilatation in the systemic circulation.

METHODS

Since 1991, 30 children (mean age, 11.3+/-3.1 years) had aortic valve replacement with the pulmonary autograft as a root replacement. All children had yearly clinical and echocardiographic follow-up.

RESULTS

There were no perioperative deaths; one child died late in a car accident. At the last follow-up (mean follow-up, 4.3+/-2.6 years), all patients were in NYHA class I. There was one early reoperation, in which the autograft had to be reconstructed due to a leaflet perforation. There were no major valve related events. All children showed normal somatic growth. The annulus diameter increased significantly from 18+/-2 at surgery to 20+/-3.5 mm at the latest follow-up (P<0.004). The sinus also increased significantly in diameter from 29+/-4 at surgery to 34+/-2 mm at the last follow-up (P<0.001). This increase in autograft size, both for the annulus and the sinus, paralleled the increase in body surface area with no evidence for unproportional dilatation. Hemodynamic measurements demonstrated physiological peak gradients of 6.8+/-2.9 mmHg and no or trivial aortic insufficiency in 95% of this rapidly growing patient population.

CONCLUSION

These data demonstrate growth of the pulmonary autograft parallel to somatic growth without undue dilatation in the systemic circulation. The hemodynamics are excellent with regard to physiological gradients and no increase in aortic insufficiency.

Outer radius-wall thickness ratio, a postmortem quantitative histology in human coronary arteries

Although the anatomy, histology and pathology of human coronary arteries have been studied extensively, little is known about the functional relationship between vessel radius and wall thickness. It is the purpose of this study to present detailed measurements and to describe this relationship covering the range from the feeding coronary artery to the arterioles. Human hearts of 10 adults less than 36 +/- 3 years old were investigated immediately postmortem. Ten cubic tissue blocks, measuring about 10 mm in length on each side, were dissected from the left ventricular wall. After fixation by immersion, 15-microm sections were prepared and outer and inner perimeters of 52 arterial segments were digitalized. Vessel radius and wall thickness were calculated and plotted to show their relationship over the whole range of vessel calibers. Outer vessel radii ranged from 100 to 3,000 microm and wall thickness from 80 to 800 microm. Plotting the outer vessel radius against the wall thickness, the data points were found to cluster around a straight line. A significant correlation between the two parameters was found (R2 = 0.79). This mathematical correlation and the good agreement of the presented results with data from other species indicate a common physiologic concept.

[Partial left ventriculectomy (Batista-procedure) as an alternative to transplantation and as a rescue procedure]

Partial left ventriculectomy (Batista operation) is one of several surgical options for the treatment of end-stage heart disease. In a 17-year-old patient who could not be accepted as a candidate for heart transplantation, this procedure was performed as an acute rescue procedure in conjunction with reduction of the left ventricle, single-stitch reconstruction of the mitral valve and removal of a ventricular thrombus. Following temporary dependence on mechanical circulatory support the patient was transferred to his own country. The clinical experience is discussed, including aspects of the surgical technique, postoperative complications, indication, relevance of mitral reconstruction and rhythm problems. It is concluded that partial left ventriculectomy can be used to treat end-stage dilated cardiomyopathy, even as an emergency operation. Further studies and experience are needed to clarify the long-term effects and clinical limitations of the procedure.

Proposed entry criteria for postoperative cardiac extracorporeal membrane oxygenation after pediatric open heart surgery

While extracorporeal membrane oxygenation (ECMO) is being used increasingly after pediatric cardiac surgery, criteria are lacking for initiating ECMO after bypass weaning. To develop clinically useful ECMO entry criteria based on parameters readily available, children were examined at postoperative pediatric intensive care unit (PICU) admission. Using hospital mortality as the primary outcome, univariate and multiple logistic regressions were performed to estimate the predictive value of clinical (age, weight, and diagnosis) and laboratory (arterial blood pressure, pH, lactate, creatine kinase, and arterial and central venous oxygen saturation [ScvO2]) variables. Data from 218 children over a 2 year period were analyzed retrospectively. Univariate regression demonstrated that age, weight, diagnosis, blood pressure, venous and arterial saturation, and lactate were significantly associated with postoperative mortality (p < 0.05). In multiple regression, ScvO2 and lactate level were found to be independent predictors and were used in a predictive model (ScvO2 odds ratio: 2.03-828.6, p = 0.016) (lactate odds ratio: 1.58 -4.20, p = 0.0002) (R2 = 0.70). Applying an 80% risk of mortality to establish entry criteria as in neonatal ECMO, PICU admission values of lactate > 70 mg/dl if ScvO2 < 60% or lactate >163 mg/dl if ScvO2 > 60% are proposed to serve as postoperative ECMO entry criteria if bypass weaning has been possible but is followed by low cardiac output.

Surgical aspects of pediatric cardiac extracorporeal membrane oxygenation

Because children with severe myocardial dysfunction have limited therapeutic options, mechanical support of a failing heart is a matter of great interest. In the setting of cardiogenic shock or severe low cardiac output and hypoperfusion, extracorporeal membrane oxygenation (ECMO) can produce decisive improvements. The criteria for successful treatment include appropriate patient selection, improved surgical techniques and experience, higher recognition and anticipation of complications, and minimized delay in initiation of ECMO. Because the need for mechanical circulatory support may arise pre-, intra-, and postoperatively, every pediatric cardiac surgeon must be familiar with the principles and the surgical aspects of ECMO.

Acute clinical deterioration in a patient with end-stage dilated cardiomyopathy and left ventricular thrombus formation

The case of a 17-year-old male patient with severe end-stage dilated cardiomyopathy and a large thrombus formation within the cavum of the left ventricle is reported. After an acute thrombectomia combined with a partial left ventriculectomy (Batista procedure), the patient was successfully treated with an appropriate left ventricular assist device (LVAD) system using a centrifugal nonocclusive pump (Biomedicus, Medtronic, Anaheim, CA, U.S.A.). Mechanical support was removed on Day 9, and the patient was discharged from the hospital on Day 19. The effectiveness of emergency mechanical support in patients with very unfavorable prognoses is discussed.

Excessive bleeding on extracorporeal membrane oxygenation after surgical repair of type I truncus arteriosus: A case report

Severe bleeding remains the most common complication of extracorporeal membrane oxygenation (ECMO) following surgical repair of congenital heart defects. We present a case of excessive hemorrhage within the first hours on ECMO support after repair of a type I truncus arteriosus. Bleeding control was achieved by surgical repair following failure of conventional interventions to control hemorrhage despite normalization of laboratory coagulation parameters. Aspects associated with bleeding and bleeding control during extracorporeal circulation after cardiac surgery are discussed.

Valve-preserving treatment of Ebstein's anomaly: perioperative and follow-up results

BACKGROUND

Ebstein's anomaly is a rare congenital cardiac defect of the tricuspid valve (TV) leading to severe tricuspid insufficiency (TI).

METHODS

In ten patients, 6 adults (39-53 years) and 4 children (5-10 years), operated between 1989 and 1995 echocardiography was performed pre and post repair and at follow-up. Patients were assessed in our institution at two cut-off points, resulting in a mean first follow-up of 17 +/-15 months and a mean second follow-up of 53+/-23 months. All patients had additional congenital cardiac defects (ASD,VSD). In all patients the TV was repaired by techniques described by Carpentier et al. with some modifications. The goal of this reparative attempt is to mobilize restricted leaflet tissue and aid coaptation through implantation of a ring.

RESULTS

Echocardiographically we were able to identify significant characteristics for the successful repair of Ebstein's anomaly. The severity of the disease is represented by the size and function of the right ventricle and the atrialized chamber, the most advanced cases exhibiting a dilated right ventricle with poor contractility. There was severe preoperative TI ( mean grade 3.2 +/- 0.3). Postoperatively TI was significantly reduced to a mean grade of 2+/-0.2. 60% of the patients demonstrated an improvement in the ratio of atrialized chamber to functional right ventricle. Right-ventricular function was improved, the mean score being 2.8+/-0.1. At follow-up I and II right-ventricular function and tricuspid insufficiency was improved in most patients and all patients benefited in quality of life.

CONCLUSION

These results suggest that surgical correction should not be delayed until severe right heart failure develops as, particularly in children, good results are achieved, improving the quality of life.

Mechanisms underlying aortic dilatation in congenital aortic valve malformation

BACKGROUND

The high incidence of aortic disease in subjects with congenital aortic valve malformations suggests a causative relationship between these 2 conditions. The histological observation in aortic dilatation/aneurysm/dissection is Erdheim cystic medial necrosis (CMN), a noninflammatory loss of smooth muscle cells (SMCs), fragmentation of elastic fibers, and mucoid degeneration.

METHODS AND RESULTS

To examine whether apoptosis is 1 of the mechanisms underlying CMN and aortic medial layer SMC loss, ascending aortic wall specimens from 32 patients were collected at cardiothoracic surgery and examined by histochemical staining and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling. From echocardiography results, 4 groups of patients were identified: bicuspid valve carriers with (bi/dil) or without (bi/0) aortic dilatation and tricuspid valve carriers with (tri/dil) or without (tri/0) aortic dilatation. Massive focal apoptosis was observed in the medial layers of bi/dil (mean apoptotic index [mAI], 8.1+/-6.0) and tri/dil (mAI, 8.1+/-8.3) compared with tri/0 (mAI, 0.9+/-1.2; P=0.0079 and P=0.037). In bi/0 (mAI, 9.1+/-5.7) compared with tri/0 (mAI, 0.9+/-1.2), rates of medial SMC apoptosis were increased (P=0.0025). Bi/dil (mean age, 40. 6+/-15.7 years) were significantly younger than tri/dil (mean age, 56.4+/-12.8 years) undergoing the same operation (P=0.0123).

CONCLUSIONS

Premature medial layer SMC apoptosis could be part of a genetic program underlying aortic disease in patients with aortic valve malformations.

IgG subclass reactivity to human cardiac myosin in cardiomyopathy patients is indicative of a Th1-like autoimmune disease

Studies performed in mice together with the demonstration of increased levels of heart-specific autoantibodies, cytokines and cytokine receptors in sera from cardiomyopathy (CMP) patients argued for a pathogenic role of autoimmune mechanisms in CMP. This study was designed to analyse the presence of IgG anti-heart antibodies in sera from patients suffering from hypertrophic and dilatative forms of CMP as well as from patients with ischaemic heart disease and healthy individuals. Patients' sera were analysed for IgG reactivity to Western-blotted extracts prepared from human epithelial and endothelial cells, heart and skeletal muscle specimens as well as from Streptococcus pyogenes. The IgG subclass (IgG1-4) reactivity to purified human cardiac myosin was analysed by ELISA. While sera from CMP patients and healthy individuals displayed comparable IgG reactivity to a variety of human proteins, cardiac myosin represented the prominent antigen detected strongly and preferentially by sera from CMP patients. Pronounced IgG anti-cardiac myosin reactivity was frequently found in sera from patients with dilatative CMP and reduced ventricular function. ELISA analyses revealed a prominent IgG2/IgG3 anti-cardiac myosin reactivity in CMP sera, indicating a preferential Th1-like immune response. Elevated anti-cytomegalovirus, anti-enterovirus IgG titres as well as IgG reactivity to nitrocellulose-blotted S. pyogenes proteins were also frequently observed in the group of CMP patients. If further work can support the hypothesis that autoreactivity to cardiac myosin represents a pathogenic factor in CMP, specific immunomodulation of this Th1- towards a Th2-like immune response may represent a promising therapeutic strategy for CMP.

Evidence against the current hypothesis of "gene dosage effects" of trisomy 21: ets-2, encoded on chromosome 21" is not overexpressed in hearts of patients with Down Syndrome

BACKGROUND

The major current concept for the pathogenesis of the Down Syndrome (DS) phenotype including congenital heart disease (CHD) is the so-called "gene dosage effect." According to this hypothesis, genes encoded by chromosome 21 at the "critical region" (which is thought to be crucial for the development of the DS phenotype) are overexpressed in the trisomic state, thus leading to an imbalance of genes as, e.g., the protooncogene ets-2, superoxide dismutase, etc.

METHODS

We studied heart biopsies obtained at surgery from 6 patients with DS and 7 patients with congenital heart disease. ets-2-mRNA steady state levels were determined by a competitive reverse transcription-polymerase chain reaction (RT-PCR) technique which allowed the determination of this gene at the attomol level.

RESULTS

ets-2 mRNA in total ventricular tissue of DS patients showed concentrations of 0.60 +/- 0.42 fg/10 ng total RNA (mean, +/- SD). When normalized versus the housekeeping gene beta-actin to rule out general transcriptional changes in that disorder, the ratio of 0.56 +/- 0.28 (mean, +/- SD) was calculated. ets-2 mRNA in total ventricular tissue of patients with non-DS CHD showed concentrations of 0.45 +/- 0.22 fg/10 ng total RNA (mean, +/-SD) and ratios of 0.48 +/- 0.35 (mean, +/-SD). No differences could be found at the p<0.05 level.

CONCLUSION

No absolute quantification of a gene incriminated in the "gene dosage effect-hypothesis" was performed so far and the only approach to (semi-) quantitative determination of the ets-2 gene using northern blotting was published on one individual DS sample only. This is the first report to clearly show that no overexpression of ets-2 can be found in heart of patients with DS, thus providing evidence against the current gene dosage effect-hypothesis.

[Hypoplastic left-heart syndrome. Initial intensive care experiences with the Norwood operation in Vienna]

Palliative surgery of the hypoplastic left heart syndrome (HLHS), whereby both pulmonary and systemic circulation are restored, was first described by Norwood in 1983. Careful ventilatory and pharmacologic modulation of the ratio of pulmonary to systemic vascular resistance are a crucial part of pre-, peri- and postoperative management. We report our experience in 3 of 7 newborns with HLHS who underwent the Norwood operation. Hemodynamic and respiratory parameters were evaluated retrospectively in these patients and we analysed the influence of diagnostic and therapeutic interventions on the course of disease before and after operation. During prostaglandin therapy two of three patients required mechanical ventilation preoperatively because of pulmonary hyperperfusion. Decreased myocardial contractility, oliguria and increased pulmonary vascular resistance characterized the postoperative course. The management included a careful application of inotropic support when necessary, adaptation of the ventilatory setting in order to modulate pulmonary perfusion and, in addition, institution of peritoneal dialysis. One patient died from staphylococcus aureus and superinfection with respiratory syncytial virus on day 41 after the operation. Maintaining an optimal balance between pulmonary and systemic blood flow is an essential aspect of postoperative management. Serum lactate and central venous oxygen saturation are helpful parameters in monitoring therapeutic measures in these patients. We conclude from our preliminary experience, that the Norwood operation might be an alternative therapeutic approach for newborns with HLHS in whom heart transplantation is not possible.

Reversal of ventricular dilatation after correction of aortic incompetence: mechanical prosthesis compared with biological procedures

BACKGROUND

The aim of the study was to compare early differences in reversal of LV dilatation between patients with mechanical prosthesis = group A (n = 51: Carbomedics = 40, Tekna/Edwards = 11) and biological procedures = group B (n = 75: pulmonary autograft = 36, aortic valve repair = 29, homograft = 10).

METHODS

Since 1,990,126 consecutive patients younger than 50 years who had surgical correction of isolated aortic incompetence underwent echocardiographic examinations preoperatively, at discharge, and at one-year follow-up. Left-ventricular (LV) diameters were measured (LVEDD, LVESD) and matched to body surface area (LVESDI, LVEDDI and fractional shortening (FS) was calculated. Aortic peak flow velocities were assessed by Doppler technique and gradients were calculated.

RESULTS

There were no significant differences preoperatively in aortic incompetence, NYHA classification, LVEDDI, LVESDI, and FS. In group B there was a significant decrease of LVESDI (p < 0.002) and LVEDDI (p < 0.001) but no change in FS at discharge. In group A a significant reduction of FS (p < 0.05) without any significant changes in LV size was observed. No patient died perioperatively or during the first year. At one-year follow-up (complete in 97.6% patients) there were no significant differences in LV diameters but group B had better ventricular function (p < 0.05) resulting in better NYHA classification (p < 0.05). Only group B had normal aortic valve gradients at discharge and at follow-up (A: 25.2 +/- 4.3 vs B: 10.2 +/- 2.4 mmHg).

CONCLUSIONS

Normal aortic valve gradients in patients after aortic valve repair or allograft replacement for chronic aortic incompetence lead to early recovery from ventricular dilatation and significantly better ventricular function at discharge. One year postoperatively they had improved ventricular function and NYHA class in comparison with patients in whom a mechanical prosthesis was implanted.

Extracorporeal membrane oxygenation in neonates

BACKGROUND

Extracorporeal membrane oxygenation (ECMO), originally developed as an artificial replacement for respiratory assistance, is decreasingly used in neonates with respiratory failure. Nevertheless, there is a constant need for this invasive and expensive neonatal treatment modality.

INTERVENTION

Review of our experience (80 recent ECMO performances because of circulatory failure) and the literature.

RESULTS

In contrary to reduced ECMO performances out of respiratory insufficiency in neonates, ECMO as circulatory support is increasingly used. Neonatal sepsis, pre- and postoperative cardiac failure, combined circulatory and respiratory failure after resuscitation and with congenital diaphragmatic hernia result in a permanent need for ECMO, whenever there are fewer ECMO treatments per year. Nonocclusive pumps, portable devices, small priming volumes and tapered anticoagulation protocols enable survival through ECMO even in virtually hopeless hemodynamic conditions. Special efforts in investigation and prevention of permanent neurological impairment, especially after severe pre-ECMO hypoxia seem to be mandatory.

CONCLUSION

ECMO remains an important tool in neonatal and pediatric intensive care. However, the number of ECMO therapies was reduced due to respiratory therapeutic progress, but indications and ECMO technology have changed.

Single needle venovenous extracorporeal membrane oxygenation using a nonocclusive roller pump for rescue in infants and children

In 1993, J.Y. Chevalier described a single needle venovenous extracorporeal membrane oxygenation (ECMO) system using a nonocclusive roller pump and alternating clamps for pulmonary support in neonates. We modified this system to use it in older children as well and for additional indications. Introducing a double raceway and 2 different sizes of tubing sets and performing percutaneous approach, we treated 21 children (age 1 day to 49 months) using this system. Indications for treatment were hypoxia and hypoxic induced myocardial dysfunction resulting from pulmonary failure, sepsis, and congenital defects. Of the children treated for neonatal indications, 7/9 survived. For 2 children ECMO was terminated because of intraventricular hemorrhage (IVH). In the pediatric group 5/7 of the children could be weaned from ECMO, and 2 children died after more than 30 days on ECMO. Two of the children who had been almost completely weaned died later because of therapy withdrawal following a brain death diagnosis. In the cardiac group, 3/5 of the children survived. We conclude that the described system is an effective venovenous ECMO system that reduces invasivity and expenditure.

Preoperative ECMO in congenital cyanotic heart disease using the AREC system

BACKGROUND

In cyanotic congenital heart disease, oxygen delivery is impaired either by reduced pulmonary perfusion or by limited entry of oxygenated blood into the systemic circulation. Additional impairment of oxygen delivery (eg, in pulmonary hypertension) leads to hypoxic cerebral damage. Preoperative extracorporeal membrane oxygenation enables oxygenation in otherwise untreatable cases.

METHODS

In 3 neonates suffering from cyanotic congenital heart disease (1 with tricuspid atresia and 2 with transposition of the great arteries) with arterial desaturation despite application of prostaglandins, balloon atrioseptostomy, and eventually inhaled nitric oxide during intermittent positive-pressure ventilation with an inspired oxygen fraction of 1, oxygenation could only be established by means of preoperative extracorporeal membrane oxygenation. We used a venovenous single-lumen cannula tidal-flow extracorporeal membrane oxygenation system described by Chevalier and associates that has previously been used for extracorporeal lung support. In this system, called AREC (assistence respiratoire extra-corporelle), alternating clamps and a nonocclusive roller pump were used.

RESULTS

All 3 survived.

CONCLUSIONS

We conclude that the AREC system enables sufficient preoperative oxygenation in patients with cyanotic congenital heart disease and hypoxia in spite of all conventional therapeutic means. This provides a stable preoperative condition for elective palliation or correction.

Epicardial branches of the coronary arteries and their distribution in the rabbit heart: the rabbit heart as a model of regional ischemia

BACKGROUND

The rabbit heart has been frequently used to study regional ischemia, but there is hardly any detailed information on the epicardial branching of the coronary arteries. Therefore, we wanted to determine whether there is a constant branching pattern and how comparable this pattern is with the human heart.

METHODS

We investigated epicardial branching of the coronary arteries in 30 adult rabbit hearts. For vessel visualisation, we used injections of Technovit, followed by corrosion.

RESULTS

We found that there is not one constant pattern but rather a bifurcation or a trifurcation of the arteria coronaria sinistra (15 of 15 hearts). The left coronary artery is always the dominant artery; a vessel comparable to the human ramus interventricularis anterior is rarely found in the bifurcation type. The ramus circumflexus is a constant but minor branch of the posterior or posterolateral division and does not originate directly from the main stem of the left coronary artery, as it does in humans. As a consequence, ligation of the left ramus interventricularis anterior leads to severe ischemic injury only where trifurcation exists (50% of our population). A ligation of the ramus circumflexus proximal to its origin produces a large posterolateral infarction in the bifurcation type (50% of our population).

CONCLUSIONS

Because a defined ischemic area is difficult to reproduce under these anatomical conditions, the rabbit heart may be a model only for regional ischemia if the investigator is knowledgeable about the distributions of the coronary arteries.

[Aortic coarctation--long-term follow-up in adults]

Surgical repair of coarctation of the aorta has been performed since 1945. Although surgical techniques have improved, problems such as restenosis and aneurysm at the operation site or hypertensive cardiovascular disease, still remain. To evaluate the long-term results after surgical repair of coarctation, 41 patients, 25 male and 16 female patients (mean age: 28 +/- 11 years, range 14-57 years), were studied 16 +/- 8 years after surgery (range 3-44 years). Mean age at surgery was 12 +/- 9 years (range 0.5-35 years). In 24 patients resection and end-to-end anastomosis had been performed, patch graft aortoplasty in nine patients, tube interposition graft in seven patients and one patient had undergone the subclavian flap technique. All patients were assessed by exact physical examination, the resting arm-to-leg systolic pressure gradient was measured by Doppler sonography, a bicycle exercise test and an echocardiogram were performed. Twenty-one patients reported postoperative symptoms such as dizziness (n = 12), headache (n = 3), cold legs (n = 10) and/or dyspnea (n = 8). In two patients the resting arm-to-leg pressure gradient was greater than 30 mm Hg, in two patients it was greater than 20 mm Hg. Gradient calculated by Doppler echocardiography ranged from 0 to 80 mm Hg (21 +/- 17 mm Hg) and showed poor correlation with the arm-to-leg pressure difference. The mean functional capacity was 89 +/- 18% (range 42-110%). In 18 patients exercise-induced hypertension was found, while in only eight patients arterial hypertension had already been known. To evaluate the morphology of the aorta MRI was performed in 28 patients. No aneurysm was found. In five patients a minimal lumen diameter as small as 9-11 mm was measured. Patients were divided into two groups according to their age at operation, group I: < 9 years (n = 19) and group II: > 9 years (n = 22). Resting blood pressure was significantly higher in group II (135 +/- 27 mm Hg vs 114 +/- 20 mm Hg, p < 0.009), anti-hypertensive medication (43% vs 11%, p < 0.04) and symptoms were more frequent in these patients (15/22 vs 6/19, p < 0.04). However at time of follow-up examination the age of patients of group II was significantly higher (33 +/- 12 vs 22 +/- 5 years, p < 0.0005). Between these two groups there was no difference in follow-up time and results of echocardiography or stress test. In conclusion, despite good long-term results after surgical repair of coarctation of the aorta, patients should be followed on a regular basis primarily in order to recognize systemic hypertension as early as possible and to improve the long-term outcome in these patients by antihypertensive treatment.

Therapeutic strategy in a 9-month-old child with pulmonary sling: need for bronchoscopic evaluation

A 9-month-old child presented suffering from repeated severe infections of the lower respiratory tract. Bronchoscopy revealed a tracheal stenosis, suggestive of a vascular anomaly of the great arteries. A second significant stenosis of the left main stem bronchus was observed that was suspected to be due to a ligamentum arteriosum. Heart catheterization confirmed the diagnosis of an abnormal origin of the left pulmonary artery (pulmonary sling). Based on the bronchoscopic and angiographic findings a pulmonary ring was suspected. A dissection of the ligamentum arteriosum was performed. At readmission 4 weeks postoperatively the child was asymptomatic and the left main bronchus was patent.

Complete repair of PA-VSD with diminutive or discontinuous pulmonary arteries by transverse thoracosternotomy

BACKGROUND

Optimal treatment and the optimal sequence of surgical and interventional steps to correct pulmonary atresia with ventricular septal defect and hypoplastic or discontinuous intrapericardial pulmonary arteries is still under discussion. Collateral arteries may be hardly accessible through median sternotomy at total correction. Bilateral transsternal thoracotomy gives wide access to the heart, both pleural spaces and hilar structures.

METHODS

We used this incision for total correction of pulmonary atresia with ventricular septal defect in 6 patients. Three had Blalock-Taussig shunts placed previously, and intrapericardial pulmonary arteries were absent in all patients but 1, in whom they were hypoplastic. Central pulmonary arteries were enlarged with pericardial patches or replaced with tube grafts; the number of unifocalized collateral arteries varied between two and eight.

RESULTS

One patient died of respiratory failure and sepsis (16.7%). Oxygen saturation increased from 76% (range, 65% to 88%) preoperatively to 96% (range 91% to 99%) postoperatively. Mean postoperative pulmonary artery pressure was 30 mm Hg (range, 28 to 34 mm Hg). One patient had to be reoperated on through the same incision due to scarring and shrinkage of the peripheral anastomoses. Six months after operation 2 patients are in New York Heart Association functional class I and 2 are in class II.

CONCLUSIONS

Transverse thoracosternotomy gives excellent access to the anatomical structures necessary to correct complex cases of pulmonary atresia with ventricular septal defect and may reduce the number of surgical procedures.

Preischemic bolus application of piroximone studied on the isolated rabbit heart--a second look including biochemical data

In a randomized prospective experimental study on 48 adult white Elco rabbits biochemical and rhythmic changes after bolus administration of the phosphodiesterase inhibitor piroximone were investigated using a working heart model. The treatment group (n = 21) intravenously received 1 mg/kg of piroximone 15 min before thoracotomy. Twenty-three untreated hearts served as the control group. From 6 hearts of each group myocardial biopsies were taken before ischemia, 4 (2/2) hearts were excluded. Hemodynamic results of a previous study with an identical protocol were reanalyzed; a biochemical analysis of myocardial high-energy phosphates was investigated after 60 min of global ischemia and at the end of the experiments after 45 min of reperfusion. Already prior to ischemia, in the treatment group depletion of high-energy phosphates was detected. After 60 min of ischemia during early reperfusion in the treatment group ATP and creatine phosphate depletion became even more evident and increased until the end of the experiments. The incidence of reperfusion-induced arrhythmias was significantly lower in the treatment group. Consequently these results and the hemodynamic results of prior studies indicate a possible positive effect of piroximone during the early reperfusion period by optimizing hemodynamics and arrhythmias.

Closure of muscular ventricular septal defects through a left ventriculotomy

OBJECTIVE

To evaluate the results of closure of muscular ventricular septal defects through a left thoracotomy.

METHODS

Records of 23 children operated consecutively between 1972 and 1990 were studied. Age of patients was 2.8 +/- 3 years (2 months-10 years), weight 8.9 +/- 5.7 kg (2.6-22 kg). Ten patients (43%) had undergone one and 4 patients (17%) two previous cardiac operations. Late follow-up was obtained from direct examination of patients or from reports of their referring physicians. Bypass time was 89 +/- 28 min (66-167 min). The aorta was cross-clamped for 44 +/- 15 min (21-66 min). Until 1977 operations were performed with moderate hypothermia and intermittent aortic cross-clamping. After 1978 deep hypothermia (20-25 degrees C) and cold crystalloid cardioplegia was used. Ventricular septal defects not accessible from other approaches were closed through a small fish-mouth incision in the apex of the left ventricle. Patients' data were sampled and stored in a computerised database. Risk factors were evaluated by stepwise logistic regression.

RESULTS

Four patients died in the hospital (17%); two died later. Two required reoperation for residual/recurrent defects. All patients, except two from abroad, were available for follow-up, which ranged from 36 months to 18 years (mean 11.3 years). All were in NYHA class I. Only two risk factors were identified: the number of ventricular septal defects (P < 0.05) and associated atrial septal defect (P < 0.02). Early echocardiographic evaluation showed good LV size and function in all except one patient, who had a perioperative septal infarction. Late echocardiography performed in six patients demonstrated normal LV shortening without evidence of regional wall abnormality.

CONCLUSIONS

Left ventriculotomy is a useful approach for closure of low muscular ventricular septal defects in selected patients.

Thoracoabdominal aneurysm repair: spinal cord protection using profound hypothermia and circulatory arrest

Between January 1991 and February 1993, 14 patients (11 male, 3 female) between 21 and 79 years of age (median 50 years) underwent reconstruction of the thoracic (n = 7) and thoracoabdominal aorta (n = 7). Four patients had previously undergone operation of the ascending aorta, and in three patients coronary artery bypass grafting had previously been performed. All patients were operated on a via a posterolateral thoracotomy using cardiopulmonary bypass with continuous blood cardioplegia and hypothermic circulatory arrest (11 degrees C nasopharyngeal temperature, flat-EEG). All patent lower intercostal and lumbar arteries (T3 to L5) were reimplanted. The 30-day mortality after repair of the thoracic aorta was 0%; after replacement of the thoracoabdominal aorta, mortality was 28.5% (n = 2). One patient died 70 days after replacement of the thoracic aorta as a consequence of a perioperative stroke. None of the surviving 11 patients developed a permanent neurological deficit or renal or cardiac dysfunction. The average intensive care stay was 6 days for patients after replacement of the thoracic aorta and 18 days for patients after replacement of the thoracoabdominal aorta. Our results suggest that use of elective hypothermia and circulatory arrest for spinal cord protection is highly effective. We, therefore, recommend this method for complex reconstructions of the thoracoabdominal aorta.

[Heart transplantation and sexuality. A study of 62 male patients]

119 adult male Austrian patients who had undergone heart transplantation between January 1985 and December 1990 were questioned on sexual functional disorders pre- and postoperatively. Questions dealt with perceived medication effects on sexual function and libido, fear of intercourse, their worries about the sexual habits of the donor, perceived changes in sexual attractiveness and body image. They were also asked how they felt about discussing sexual matters with their doctors. 62 patients returned fully completed questionnaires. 75% of the patients were more than 45 years old (45 to 67 years). Heart transplantation had been carried out at least once longest seven years before. The patients reported a significant postoperative increase of libido accompanied by a significant decrease of physical complaints at intercourse. Problems with potency (impaired erectile rigidity) persisted, however, (Table 4, Figure 1). 23% of the patients reported that since transplantation sexuality had become a problem for them. 42% wanted to undergo treatment if available. 29% stated that sexual matters had clearly improved. 31% suspected that medication adversely affected sexual functioning, and 23% stated that in their opinion it contributed to a lowered libido. 15% felt themselves much more sexually attractive after they had undergone surgery, and 13% were considered more sexually attractive by their spouses. Only four patients reported avoiding intercourse for health reasons. One patient confirmed that he was fantasizing about the sexual habits of the unknown donor of his heart. It seems that physicians often neglect to talk about sexual matters with their heart transplant patients, though the patients consider it a very important topic (Figure 2).(ABSTRACT TRUNCATED AT 250 WORDS)