Abnormal distribution of pulmonary blood flow after the Glenn shunt or Fontan procedure: risk of development of arteriovenous fistulae.

Abstract

Since the Fontan procedure results in low pulsatile pulmonary blood flow similar to that seen in patients with a Glenn shunt, it may also be associated with abnormal distribution of flow to the lower lung lobes and with the development of pulmonary arteriovenous fistulae (PAVF). In 12 patients 0.8 to 4.5 years after Fontan procedure and in 20 patients 0.2 to 18 years after receipt of Glenn shunts we assessed ventilation (with '33Xe) and perfusion (after a peripheral injection of 99mTc-macroaggregated albumin) to compare upper to lower lobe distribution of blood flow with that in a control group. The presence of PAVF was assessed by radionuclide activity in kidneys and the brain and by a twodimensional echocardiographic contrast study. A decreased upper/lower lobe perfusion ratio was noted in 13 of 20 patients with Glenn shunts (65%) and correlated with the time after surgery (p < .05). Despite the shorter follow-up period, two of 12 (16%) patients who had undergone the Fontan procedure also had a decreased upper/lower lobe perfusion ratio, and one of these developed right heart failure. Brain and kidney radionuclide counts above control values were observed in all patients with Glenn shunts and in 11 of 12 patients who had the Fontan operation. However, in only five of 20 (25%) patients with Glenn shunts were PAVF confirmed by the two-dimensional echocardiographic contrast study. Three of the five patients with PAVF had Glenn shunts of long duration. While only two of five patients with PAVF had a decreased upper/lower lobe perfusion ratio at the time of the study, this abnormality may have been present in the other three at an earlier stage. Our data suggest that a decreased ratio of upper/lower lobe perfusion may be one of several factors associated with the development of PAVF after a Glenn shunt. Also, longer follow-up of patients who have had a Fontan procedure will be necessary to determine whether they are also a group at risk. Circulation 72, No. 3, 471-479, 1985 We therefore performed ventilation/perfusion lung scans to determine the distribution of pulmonary blood flow in patients after the Fontan procedure (RA-PA and RA-RV). We assessed the presence of PAVF by the scintigraphic appearance of 99mTc-macroaggregated albumin (MAA) in the brain and kidneys after a peripheral intravenous injection and by two-dimensional echocardiographic contrast studies. Our findings were compared with those obtained in patients with Glenn shunts and in normal subjects.

Orthotopic Heart Transplantation for Congenital Heart Disease: An Alternative for High-Risk Fontan Candidates?

“…The unsatisfactory results of OHT in failing Fontan find a multifactorial genesis. 23,24 Calculation of pulmonary vascular resistance in pretransplant evaluation is hampered by low flow or by nonequal blood-flow distribution in the pulmonary arterial tree. Microvascular sludging and thromboemboli can occur in the pulmonary vasculature, while arterio-venous malformations may false trans-pulmonary gradients, anticipating a potential for right ventricular failure.…”

Exercise capacity and impact of exercise training in patients after a Fontan procedure: A review

“…Deconditioning may contribute to this deterioration because aerobic exercise training has been shown to improve these patients' functional capacity (18)(19)(20)(21). Nevertheless, this long-term decline in exercise tolerance following the procedure may also be related to the disease progression (17) or to the reduced capacity to increase the cardiac output (Q) in response to exercise secondary to the Fontantype circulation, thus limiting the oxygen transport to the periphery (22,23). Slower oxygen uptake kinetics, ie, the precise integration of the cardiorespiratory system required to transport the oxygen from the atmosphere through active muscles to achieve oxidative phosphorylation (24), is well documented in patients with coronary artery disease, cyanotic congenital heart disease or heart failure (25)(26)(27)(28)(29)(30)(31).…”

“…In fact, the change in the patients' physiology as a result of the Fontan procedure does not allow the Q to adequately increase in response to exercise, as it would in healthy individuals. Because the pulmonary blood flow is not driven by the right ventricle, it is reduced and almost nonpulsatile (22,23). This leads to a limited increase in pulmonary blood flow in response to exercise, a reduced left ventricle filling and a smaller stroke volume, resulting in a reduced increase in Q.…”

Pediatric Cardiology and Cardiovascular Surgery: 1950-2000

“…Historically, the development of pulmonary arteriovenous malformations after the classic Glenn anastomosis has been very well documented, but in none of the substantial reviews of this complication emanating from either Yale or Toronto was hepatic venous exclusion considered to be causal. 145,146 Indeed, the Toronto group speculated that maldistribution of flow to the dependent portion of the right lung and lack of pulsatile blood flow were possible causes. 146 In one patient in our institution who underwent the Laks modification of the Fontan procedure with diversion of inferior caval blood to the right lung and superior caval blood to the left lung, 147 pulmonary arteriovenous malformations developed only in the left lung.…”