Effects of elevated coronary sinus pressure on coronary blood flow and left ventricular function. Implications after the Fontan operation

Paroxysmal supraventricular tachycardia as a major clinical presentation of the primary coronary sinus lymphoma: A case report

RATIONALE

Primary cardiac lymphoma is a rare tumor, especially a tumor located in coronary sinus (CS). The most common symptom of cardiac tumors is dyspnea, accounting for 64%, followed by chest pain, accounting for 26%. However, the cases with paroxysmal supraventricular tachycardia (SVT) as a major clinical presentation are extremely rare.

PATIENT CONCERNS

We report a 55-year-old female patient with primary CS lymphoma and paroxysmal SVT.

DIAGNOSES

After the surgical resection, pathology revealed the evidence of diffuse large B-cell lymphoma.

INTERVENTIONS

The patient underwent chemotherapy after CS tumor resection.

OUTCOMES

The patient was disease-free during the 6-month follow-up.

LESSONS

CS enlargement may be the cause of SVT. Echocardiography should focus on the CS section to arrive at the right diagnosis.

The failing Fontan

Nearly 50 years back, Francis Fontan pioneered an operation for tricuspid atresia that bears his name today. The operation has since undergone numerous modifications and continues to be widely applied to an array of single ventricles. Despite restoring normal oxygen levels in the body, the operation creates a neoportal system where adequate cardiac output can be generated only at the expense of increased systemic venous congestion. This results in slow but relentless damage to the end organ systems especially the liver. Continuous surveillance of the patient to monitor this circulation, that will ultimately fail, is of paramount importance. Timely medical and cardiac catheterization and surgical intervention can extend the life span of Fontan patients. Ultimately a change of the hemodynamic circuit in the form of heart transplantation or ventricular assist device will be required to salvage the failing Fontan circuit.

Outcomes of the Conversion of the Fontan-Kreutzer Operation to a Total Cavopulmonary Connection for the Failing Univentricular Circulation

Background

The Fontan-Kreutzer procedure (FK) was widely performed in the past, but in the long-term generated many complications resulting in univentricular circulation failure. The conversion to total cavopulmonary connection (TCPC) is one of the options for treatment.

Objective

To evaluate the results of conversion from FK to TCPC.

Methods

A retrospective review of medical records for patients who underwent the conversion of FK to TCPC in the period of 1985 to 2016. Significance p < 0,05.

Results

Fontan-type operations were performed in 420 patients during this period: TCPC was performed in 320, lateral tunnel technique in 82, and FK in 18. Ten cases from the FK group were elected to conversion to TCPC. All patients submitted to Fontan Conversion were included in this study. In nine patients the indication was due to uncontrolled arrhythmia and in one, due to protein-losing enteropathy. Death was observed in the first two cases. The average intensive care unit (ICU) length of stay (LOS) was 13 days, and the average hospital LOS was 37 days. A functional class by New York Heart Association (NYHA) improvement was observed in 80% of the patients in NYHA I or II. Fifty-seven percent of conversions due to arrhythmias had improvement of arrhythmias; four cases are cured.

Conclusions

The conversion is a complex procedure and requires an experienced tertiary hospital to be performed. The conversion has improved the NYHA functional class despite an unsatisfactory resolution of the arrhythmia.

Left atrial compression and the mechanism of exercise impairment in patients with a large hiatal hernia

OBJECTIVES

The purpose of this study was to determine the association between cardiac compression and exercise impairment in patients with a large hiatal hernia (HH).

BACKGROUND

Dyspnea and exercise impairment are common symptoms of a large HH with unknown pathophysiology. Studies evaluating the contribution of cardiac compression to the pathogenesis of these symptoms have not been performed.

METHODS

We collected clinical data from a consecutive series of 30 patients prospectively evaluated with resting and stress echocardiography, cardiac computed tomography, and respiratory function testing before and after laparoscopic HH repair. Left atrial (LA), inferior pulmonary vein, and coronary sinus compression was analyzed in relation to exercise capacity (metabolic equivalents [METs] achieved on Bruce treadmill protocol).

RESULTS

Exertional dyspnea was present in 25 of 30 patients (83%) despite normal mean baseline respiratory function. Moderate to severe LA compression was qualitatively present in 23 of 30 patients (77%) on computed tomography. Right and left inferior pulmonary vein and coronary sinus compression was present in 11 of 30 (37%), 12 of 30 (40%), and 26 of 30 (87%) patients, respectively. Post-operatively, New York Heart Association functional class and exercise capacity improved significantly (number of patients in New York Heart Association functional classes I, II, III, and IV: 6, 11, 11, and 2 vs. 26, 4, 0, and 0, respectively, p < 0.001; METs [percentage predicted]: 75 ± 24% vs. 112 ± 23%, p < 0.001) and resolution of cardiac compression was observed. Absolute change in LA diameter on the echocardiogram was the only independent cardiorespiratory predictor of exercise capacity improvement post-operatively (p = 0.006).

CONCLUSIONS

We demonstrate, for the first time, marked exercise impairment and cardiac compression in patients with a large HH and normal respiratory function. After HH repair, exercise capacity improves significantly and correlates with resolution of LA compression.

The failing Fontan: options for surgical therapy

The Fontan procedure has been a significant contribution to the therapeutic armamentarium of congenital heart surgeons for the treatment of single ventricle anomalies. However, it has its limitations. Patients may have failure of the Fontan circulation acutely postoperatively or late during the long-term follow-up. Early failure is often related to an intraoperative myocardial injury or unsuspected elevated pulmonary vascular resistance; this has a very high mortality. Late failure of the Fontan procedure may present with symptoms typical for heart failure. However, protein-losing enteropathy is another condition related to late failure of the Fontan operation. Late failure may be related to a number of different factors, many of which are amenable to reoperation. Every effort should be made to identify which hemodynamic factors are responsible for late failures. However, cardiac transplantation will likely be necessary for the majority of patients.

Does normothermic normokalemic simultaneous antegrade/retrograde perfusion improve myocardial oxygenation and energy metabolism for hypertrophied hearts?

BACKGROUND

Beating-heart valve surgery appears to be a promising technique for protection of hypertrophied hearts. Normothermic normokalemic simultaneous antegrade/retrograde perfusion (NNSP) may improve myocardial perfusion. However, its effects on myocardial oxygenation and energy metabolism remain unclear. The present study was to determine whether NNSP improved myocardial oxygenation and energy metabolism of hypertrophied hearts relative to normothermic normokalemic antegrade perfusion (NNAP).

METHODS

Twelve hypertrophied pig hearts underwent a protocol consisting of three 20-minute perfusion episodes (10 minutes NNAP and 10 minutes NNSP in a random order) with each conducted at a different blood flow in the left anterior descending coronary artery (LAD [100%, 50%, and 20% of its initial control]). Myocardial oxygenation was assessed using near-infrared spectroscopic imaging. Myocardial energy metabolism was monitored using localized phosphorus-31 magnetic resonance spectroscopy.

RESULTS

With 100% LAD flow, both NNAP and NNSP maintained myocardial oxygenation, adenosine triphosphate, phosphocreatine, and inorganic phosphate at normal levels. When LAD flow was reduced to 50% of its control level, NNSP resulted in a small but significant decrease in myocardial oxygenation and phosphocreatine, whereas those measurements did not change significantly during NNAP. With LAD flow further reduced to 20% of its control level, both NNAP and NNSP caused a substantial decrease in myocardial oxygenation, adenosine triphosphate, and phosphocreatine with an increase in inorganic phosphate. However, the changes were significantly greater during NNSP than during NNAP.

CONCLUSIONS

Normothermic normokalemic simultaneous antegrade/retrograde perfusion did not improve, but slightly impaired myocardial oxygenation and energy metabolism of beating hypertrophied hearts relative to NNAP. Therefore, NNSP for protection of beating hypertrophied hearts during valve surgery should be used with extra caution.

Cross-Talk Between Cardiac Muscle and Coronary Vasculature

The cardiac muscle and the coronary vasculature are in close proximity to each other, and a two-way interaction, called cross-talk, exists. Here we focus on the mechanical aspects of cross-talk including the role of the extracellular matrix. Cardiac muscle affects the coronary vasculature. In diastole, the effect of the cardiac muscle on the coronary vasculature depends on the (changes in) muscle length but appears to be small. In systole, coronary artery inflow is impeded, or even reversed, and venous outflow is augmented. These systolic effects are explained by two mechanisms. The waterfall model and the intramyocardial pump model are based on an intramyocardial pressure, assumed to be proportional to ventricular pressure. They explain the global effects of contraction on coronary flow and the effects of contraction in the layers of the heart wall. The varying elastance model, the muscle shortening and thickening model, and the vascular deformation model are based on direct contact between muscles and vessels. They predict global effects as well as differences on flow in layers and flow heterogeneity due to contraction. The relative contributions of these two mechanisms depend on the wall layer (epi- or endocardial) and type of contraction (isovolumic or shortening). Intramyocardial pressure results from (local) muscle contraction and to what extent the interstitial cavity contracts isovolumically. This explains why small arterioles and venules do not collapse in systole. Coronary vasculature affects the cardiac muscle. In diastole, at physiological ventricular volumes, an increase in coronary perfusion pressure increases ventricular stiffness, but the effect is small. In systole, there are two mechanisms by which coronary perfusion affects cardiac contractility. Increased perfusion pressure increases microvascular volume, thereby opening stretch-activated ion channels, resulting in an increased intracellular Ca2+transient, which is followed by an increase in Ca2+sensitivity and higher muscle contractility (Gregg effect). Thickening of the shortening cardiac muscle takes place at the expense of the vascular volume, which causes build-up of intracellular pressure. The intracellular pressure counteracts the tension generated by the contractile apparatus, leading to lower net force. Therefore, cardiac muscle contraction is augmented when vascular emptying is facilitated. During autoregulation, the microvasculature is protected against volume changes, and the Gregg effect is negligible. However, the effect is present in the right ventricle, as well as in pathological conditions with ineffective autoregulation. The beneficial effect of vascular emptying may be reduced in the presence of a stenosis. Thus cardiac contraction affects vascular diameters thereby reducing coronary inflow and enhancing venous outflow. Emptying of the vasculature, however, enhances muscle contraction. The extracellular matrix exerts its effect mainly on cardiac properties rather than on the cross-talk between cardiac muscle and coronary circulation.

Conversion of atriopulmonary Fontan to extracardiac total cavopulmonary connection improves cardiopulmonary function

BACKGROUND

Experimental studies showed that extracardiac total cavopulmonary connection provides superior hemodynamics than atriopulmonary Fontan.

METHODS

We prospectively assessed the impact of conversion of atriopulmonary Fontan to extracardiac total cavopulmonary connection on exercise capacity and cardiac function in 6 consecutive patients.

RESULTS

Six months after conversion to extracardiac total cavopulmonary connection, we observed an increase in peak oxygen uptake in all patients (p=0.01;+17%). This improvement was associated to an increase of peak O(2) pulse (p=0.01;+16%), but no change in peak heart rate, arterial oxygen saturation at peak exercise, and pulmonary function. Ventricular ejection fraction did not change significantly after surgery. Conversion was associated with an improvement in heart failure symptoms as assessed by the New York Heart Association classification. Patients who had undergone additional anti-arrhythmia surgery for atrial fibrillation had no recurrence of arrhythmia at follow-up.

CONCLUSION

Data indicate that conversion to extracardiac total cavopulmonary connection is associated with an improvement of cardiopulmonary function and heart failure symptoms. Improved exercise capacity is due to an increase in O(2) pulse and may reflect an improved cardiac stroke volume after the operation.

Site of coronary sinus drainage does not significantly affect coronary flow reserve in patients long term after Fontan operation

This study was designed to investigate the impact of postoperative coronary sinus drainage pressure on coronary flow reserve (CFR) assessed by Doppler guidewire in patients long term after Fontan operation. Twenty-nine patients (median age, 17.4 years female, 11) at a median of 10.6 years after Fontan operation were examined with intracoronary Doppler guidewire during cardiac catheterization. Fourteen patients had coronary sinus (CS) drainage to the systemic venous atrium and 15 patients had CS drainage to the pulmonary venous atrium after Fontan operation. Median CS drainage pressure was significantly higher in systemic venous CS drainage compared to pulmonary venous CS drainage (11 vs 5 mmHg, p < 0.0001). Median CFR values for the right and left coronary artery did not differ significantly with respect to CS drainage. There was a positive correlation between coronary flow reserve and pulmonary arteriolar resistance (p < 0.05) in multivariate regression analysis. The site of coronary drainage into the systemic atrium or the pulmonary venous atrium did not significantly affect CFR. Our data do not support a surgical strategy of elective redirection of coronary sinus blood to a low-pressure compartment but support an early staged approach. The positive correlation between CFR and pulmonary resistance demands further evaluation.

Extracorporeal membrane oxygenation support of the Fontan and bidirectional Glenn circulations

BACKGROUND

Extracorporeal membrane oxygenation can provide effective mechanical circulatory support for the failing circulation in children. Patients with failing Fontan and bidirectional Glenn physiology present additional challenges both for extracorporeal membrane oxygenation cannulation and support. We report our institutional experience in patients with cavopulmonary connections who received extracorporeal membrane oxygenation.

METHODS

We performed a retrospective review of 20 patients with cavopulmonary connections (14 Fontan and 6 bidirectional Glenn) who were supported with extracorporeal membrane oxygenation from a single, large pediatric tertiary care center.

RESULTS

Of the 20 patients, ten were supported and decannulated successfully (50%) (two after cardiac transplantation), but only six (30%) are alive at follow-up. Of the 14 Fontan patients, seven (50%) were withdrawn from extracorporeal membrane oxygenation or died within 48 hours of decannulation due to lack of myocardial recovery or severe neurologic injury. All four adult-sized (> 40 kg) Fontan patients were withdrawn from extracorporeal support. The seven Fontan patients who were successfully decannulated survived to discharge, and five (35.7%) are alive at follow-up (median 35 months; range, 7 to 140 months). Of the six bidirectional Glenn patients, five died before hospital discharge and the lone survivor has neurologic injury at follow-up.

CONCLUSIONS

Patients with failing Fontan and bidirectional Glenn physiology present significant challenges to successful extracorporeal membrane oxygenation support. While the morbidity and mortality rates are high, there are select patients for whom extracorporeal support can be effective and lifesaving as a short-term resuscitative intervention.

Perfusion-contractility matching during Fontan circulation

We investigated the relationship between coronary perfusion pressure (CPP) and myocardial contractility and the effects of an acute elevation of right atrial pressure (RAP) on this relationship in an experimental model of Fontan circulation in 6 anesthetized open-chest dogs with isolated perfused coronary arteries. The relationship between CPP and Ees could be described by biphasic J-shaped curves which were nearly identical before and under Fontan circulation. While above a "critical" CPP (72 +/- 9 mmHg vs. 81 +/- 8 mmHg, n.s.) the changes of CPP did not affect Ees, below this level the decrease of CPP resulted in a progressive decrease of Ees. Under Fontan circulation, the progressive increase of RAP did not influence Ees at CPP = 100 mmHg, led to a moderate decrease of Ees at CPP = 75 mmHg and severe decrease at CPP = 60 mmHg. Thus, both coronary arterial and venous pressure affect myocardial contractility after Fontan procedure.

Fontan conversion to total cavopulmonary connection and arrhythmia ablation: clinical and functional results

OBJECTIVES

To assess the early results of conversion from atriopulmonary to total cavopulmonary connection in patients with failing Fontan operation.

DESIGN

Early clinical and instrumental evaluation of patients undergoing conversion from atriopulmonary to total cavopulmonary connection from April 1999 to November 2000.

SETTING

Tertiary referral centre for congenital heart disease.

PATIENTS

11 Fontan patients (mean (SD) age 20.9 (6.7) years) with refractory arrhythmias or ventricular dysfunction.

INTERVENTIONS

Total cavopulmonary connection, intraoperative ablation, and AAIR pacemaker implantation.

MAIN OUTCOME MEASURES

Holter monitoring, transoesophageal atrial stimulation, ergometric test, and myocardial scintigraphy at a mean (SD) follow up of 16.8 (5.6) months.

RESULTS

One early postoperative death occurred. During follow up three patients had relapse of atrial tachycardia, controlled by medical treatment, and two were pacemaker dependent. Transoesophageal stimulation did not induce atrial tachycardia in any patient. Ergometric test showed a diminished exercise tolerance in all but one patient. Mean minute ventilation and maximum oxygen consumption were 62% and 40% of their respective predicted values. Myocardial scintigraphy showed reversal of rest or exercise dysfunction in five patients and improved systemic ventricular function in seven. Mean basal ejection fraction increased from 39.4% (95% confidence interval (CI) 32% to 46%) to 46.5% (95% CI 41.7% to 51.2%) and ejection fraction on effort from 42.3% (95% CI 33.9% to 50.7%) to 50.2% (95% CI 44.5% to 55.9%).

CONCLUSIONS

Our data show that total cavopulmonary connection associated with intraoperative ablation and pacemaker implantation allows for better control of arrhythmias and improves ventricular function in the majority of patients with failing Fontan.

The extracardiac Fontan procedure

The extracardiac modification of the Fontan procedure for complex single ventricle congenital cardiac disease is the latest attempt at improving on both the short-term and long-term results of this operation. This procedure differs from other modifications in that the inferior vena cava is detached from the heart and connected via a conduit to the pulmonary artery. It uses the fluid dynamic advantages of the cavopulmonary connection type of Fontan procedure but has other potential advantages as well. It is not necessary to cross-clamp the aorta to perform this procedure. Although quite a bit of prosthetic material is necessary to make the appropriate connections, none of this is exposed to the systemic circulation. Atrial flutter, a common early and late complication of other modifications of the Fontan procedure, appears to be less common with the extracardiac technique. The major disadvantages of this modification are the greater exposure of the venous pathway to potentially thrombogenic surfaces and the larger amount of prosthetic material involved in constructing the connection of the inferior vena cava to the pulmonary artery. Although the intermediate-term results with this procedure have been very favorable, issues that remain unresolved include the growth potential of the pathway, risk of late obstruction, and risk of atrial arrhythmias occurring late. Copyright 1998 by W.B. Saunders Company

Conversion of the atriopulmonary Fontan connection to a total cavopulmonary connection

Right atrial-to-pulmonary artery anastomosis (modified Fontan-Kreutzer operation) often results in substantial enlargement of the right atrium over time. Massive right atrial dilatation can cause loss of laminar flow, stasis, compression of the right pulmonary veins posteriorly, and leftward shift of the atrial septum. Some patients may develop arrhythmias related to atrial distension and multiple suture lines. Chronic elevation of the central venous pressure may cause liver dysfunction and/or protein-losing enteropathy in some patients. Some patients with atriopulmonary Fontan connections who develop a decline in functional status may benefit from conversion to a total cavopulmonary connection. Patients with significant ventricular dysfunction can usually only be treated by cardiac transplantation. However, other problems may be successfully managed by revision of the atriopulmonary Fontan connection to a total cavopulmonary anastomosis. Conversion to a total cavopulmonary connection should improve cardiac output by restoring laminar flow, by relieving compression of the right pulmonary veins, and by alleviating the leftward displacement of the atrial septum. Copyright 1998 by W.B. Saunders Company

Late results of extracardiac Fontan repair

The Fontan procedure by means of an extracardiac conduit was initially proposed for patients presenting with anomalies of intra-atrial anatomy. We extended this technique to all patients with functional anatomic single ventricle. Between 1988 and 1998, 206 patients with complex cardiacanomalies underwent a total extracardiac cavopuolmonary connection. In 202 patients we used a conduit, in 4 patients we performed an IVC to pulmonary artery direct anastomosis. Ten patients underwent Conversion of a filing atriopulmonary Fontan procedure to a total extracardiac cavopulmonary connection. Early deaths occurred in 10% of patients and the extracardiac conduit was taken down in 3 additional patients. The cause of death was myocardial failure in 13 patients. Pulmonary distortion or hypoplasia in 6. No deaths have occurred in our last 45 patients. We observed no cases of conduit obstruction and thrombosis. Arrthymias were present in 16 patients. Ten patients underwent conversion of a formed modified Fontan. There were no immediate postoperative deaths. These results demonstrate that the total extracardiac cavopulmonary connection provide good early and mildterm results and is the technique of choice for a Fontan type repair. Copyright 1999 by W.B. Saunders Company

Extracardiac conduit fontan procedure: early and intermediate results

OBJECTIVE

The extracardiac Fontan procedure, as compared with classic atriopulmonary connections, may have the potential for optimizing ventricular and pulmonary vascular function by maximizing the laminar flow principle, by the avoidance of intra-atrial suture lines and cardiac manipulation, and by minimizing cardiopulmonary bypass time. In this study the clinical results of this procedure are assessed.

METHODS

From January 1990 until January 1997, 45 patients (33 males and 12 females) with a median age of 4.0 years (range 2.7-38 years) underwent an extracardiac Fontan procedure for univentricular physiology. The underlying diagnoses included tricuspid atresia (n=19), double-inlet left ventricle (n=11), and complex anomalies (n=15). Forty patients (89%) were in sinus rhythm. The median ventricular ejection fraction was 60%. In 37 patients (82%) the procedure was staged.

RESULTS

Median cardiopulmonary bypass time was 72 min, with a decrease to a median time of 24 min in the last ten patients. Aortic cross-clamping was avoided in 33 patients (73%). The intraoperative Fontan pressure and transpulmonary gradient were low: 13.6+/-3.2 and 8.5+/-3.9 mmHg, respectively. Transient supraventricular tachyarrhythmias were observed in six patients (13%). There was no early or late mortality. At a median follow-up of 64 months (range 26-105 months), 39 patients (87%) were in NYHA class I, four (9%) were in NYHA class II, and two (4%) were in class III. Forty patients (89%) remained in sinus rhythm. The median ventricular ejection fraction was 59%. The median arterial oxygen saturation raised from 82% preoperatively to 97%. Functional class (P=0.02), maintenance of sinus rhythm (P=0.04), and preservation of ventricular function (P=0.05) was superior in patients who were appropriately staged. None of the patients had atrial thrombus, chronic pleural effusions, or protein losing enteropathy.

CONCLUSIONS

In the majority of patients, the extracardiac Fontan procedure, when performed as a staged procedure, provides excellent early and midterm results in terms of quality of life, maintenance of sinus rhythm, and preservation of ventricular function.

Revision of previous Fontan connections to total extracardiac cavopulmonary anastomosis: A multicenter experience

BACKGROUND

Conversion to total extracardiac cavopulmonary anastomosis is an option for managing patients with dysfunction of a prior Fontan connection.

METHODS

Thirty-one patients (19.9 +/- 8.8 years) underwent revision of a previous Fontan connection to total extracardiac cavopulmonary anastomosis at four institutions. Complications of the previous Fontan connection included atrial tachyarrhythmias (n = 20), progressive heart failure (n = 17), Fontan pathway obstruction (n = 10), effusions (n = 10), pulmonary venous obstruction by an enlarged right atrium (n = 6), protein-losing enteropathy (n = 3), right atrial thrombus (n = 2), subaortic stenosis (n = 1), atrioventricular valve regurgitation (n = 3), and Fontan baffle leak (n = 5). Conversion to an extracardiac cavopulmonary connection was performed with a nonvalved conduit from the inferior vena cava to the right pulmonary artery, with additional procedures as necessary.

RESULTS

There have been 3 deaths. Two patients died in the perioperative period of heart failure and massive effusions. The third patient died suddenly 8 months after the operation. All surviving patients were in New York Heart Association class I (n = 20) or II (n = 7), except for 1 patient who underwent heart transplantation. Early postoperative arrhythmias occurred in 10 patients: 4 required pacemakers, and medical therapy was sufficient in 6. In 15 patients, pre-revision arrhythmias were improved. Effusions resolved in all but 1 of the patients in whom they were present before revision. The condition of 2 patients with protein-losing enteropathy improved within 30 days.

CONCLUSIONS

Conversion of a failing Fontan connection to extracardiac cavopulmonary connection can be achieved with low morbidity and mortality. Optimally, revision should be undertaken early in symptomatic patients before irreversible ventricular failure ensues.

Surgical variations and flow dynamics in cavopulmonary connections: A historical review

Cavopulmonary connections (CPC) have been extensively used in the palliation of complex forms of congenital heart disease requiring some form of right heart bypass. The concept has evolved from unilateral CPC to total CPC (TCPC) in an attempt to prolong the palliated state, but the physiological implications remain only partially understood. We summarize some of the modifications and experimental data and their impact on flow distribution after the Fontan procedure. Copyright 1998 by W.B. Saunders Company

Acute elevation of coronary venous pressure does not affect left ventricular contractility in the normal and stressed swine heart: implications for the Fontan operation

OBJECTIVE

After the Fontan operation the right atrium and, thus, the coronary sinus are connected to the pulmonary arterial system, which causes the coronary venous pressure to increase. We investigated the acute effects of elevation of coronary venous pressure on baseline hemodynamics, coronary venous flow, and left ventricular contractility.

METHODS

In acutely instrumented pigs, during complete right heart bypass and during constant cardiac output, pressure in the right atrium, right ventricle, and coronary sinus was altered by a height-adjustable reservoir. At various levels of coronary venous pressure (up to 4 kPa or up to 30 mm Hg), flow from the reservoir was measured and left ventricular hemodynamics and contractility were measured from catheter-derived left ventricular pressure and (conductance) volume data. Contractility of the left ventricle was assessed by the end-systolic pressure-volume relationship derived during an unloading intervention by adjusting the bypass pump speed.

RESULTS

Left ventricular end-diastolic pressure increased slightly (about 5%) with each kilopascal increase in coronary venous pressure, most likely related to diastolic ventricular interaction. No other changes in hemodynamic parameters occurred. Neither coronary venous flow nor left ventricular contractility was influenced by changes in coronary venous pressure. Imposing myocardial stress with dobutamine, 10 microg/kg per minute, did not change these findings.

CONCLUSION

Increasing coronary venous pressure to 4 kPa in the intact circulation with intact autoregulation does not affect coronary flow or left ventricular contractility. We found no experimental evidence for the usefulness of diversion of the coronary sinus to the left atrium during Fontan-type operations

Revision of previous Fontan connections to extracardiac or intraatrial conduit cavopulmonary anastomosis

BACKGROUND

In patients who have received an atriopulmonary Fontan connection, complications such as right pulmonary vein obstruction, atrial arrhythmias, and thromboembolism are often secondary to right atrial enlargement. When such complications develop despite good ventricular function, there are few management options available. Extracardiac or intraatrial conduit cavopulmonary anastomosis, which improves central systemic venous flow patterns, avoids atrial distention, and does not involve the extensive atrial suturing required by other forms of cavopulmonary anastomosis, may provide relief for this group of patients.

METHODS

Between October 1992 and October 1995, 7 patients presented 8 to 20 years after atriopulmonary connection with severe right atrial dilatation (7), Fontan pathway obstruction (4), progressive congestive heart failure (4), atrial tachydysrhythmias (3), right atrial thrombus (1), obstruction of right pulmonary veins by an enlarged right atrium (1), and subaortic stenosis (1). After evaluation of the options, they underwent revision of the atriopulmonary connection to extracardiac (5) or intraatrial (2) conduit cavopulmonary anastomosis.

RESULTS

One patient with severe cachexia, in whom transplantation was contraindicated for social reasons, died in the early postoperative period of massive effusions. Two patients eventually required permanent pacing for atrial dysrhythmias (1) or complete heart block secondary to subaortic fibromuscular resection (1), and 2 demonstrated marked improvement in unstable preoperative rhythm disturbances. At a median follow-up of 17 months, 4 of the 6 survivors were functioning at higher New York Heart Association levels than preoperatively, and 1 had recently undergone heart transplantation.

CONCLUSIONS

In properly selected patients with atrial complications, revision of a prior Fontan connection to extracardiac or intraatrial conduit cavopulmonary anastomosis appears to be a viable option.