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Journal of the American College of Cardiology Vol. 56, No. 2, 2010 2010 by the American College of Cardiology Foundation ISSN 0735-1097/$36.00PubDITORIAL COMMENT
ur Decades ofe Fontan Operation
id We Ever Have a Leg to Stand on?*
iane Marelli, MD
ontreal, Quebec, Canada
Experimental research on dogs enabled us to check the technicalfeasibility of this procedure, but there were no survivors for morethan a few hours.
Fontan and Baudet (1971) (1)
audius Galen (circa AD 129 to 200) held that there wereeparate blood systems, nutritive and respiratory, with fuelplied by the liver and fumes exiting through the wind-e (2). The concept of the heart as a pump would wait
other 1,500 years. In 1628, William Harvey (3) put forthidea of the heart as a source of propulsion when he
served the auricles and 2 ventricles beating in a livingmmal (2). With the advent of human dissections, Har-s experiments in the forearm led him to conclude that
nce the Blood could not well, because of the interposinglves, be sent by the Veins to the Limbs, it should be sentough the Arteries, and return though the Veins, whoseves did not oppose its course that way (3). Harvey is thusdited for his discovery of the circulation: I beganvately to consider if it [the heart] had movement in acle (3). These cornerstone observations escorted us intoenturies of research that would expand our understandingthe normal cardiovascular circulation.
See page 144
After birth, the aortic and pulmonary circulation areanged in series with pulsatile subpulmonary and subaortictricles. In the occurrence of a functional single ventricleause of tricuspid atresia or a double-inlet single ventricle,systemic and pulmonary circulation are connected in
rallel with complete admixing of oxygenated and deoxy-ated blood (4). Over 300 years after Harveys discovery,
well and Glenn (5) would construct a pump to divert caval
itorials published in the Journal of the American College of Cardiology reflect the
lished by Elsevier Inc.enrepage
s of the authors and do not necessarily represent the views of JACC or theerican College of Cardiology.rom the McGill Adult Unit for Congenital Heart Disease (MAUDE Unit),Gill University, Montreal, Quebec, Canada.urn into the pulmonary artery, bypassing the right heartd giving rise to the Glenn anastomosis.In Fontan and Baudets initial report (1), they state,e were of the opinion that a hypertrophied right atriumin tricuspid atresia, could supply the additional workresented by a pulmonary arterial pressure higher that the
t atrial pressure . . . it seemed indispensible to provide theht atrium with valve homografts. The opinion turnedt to be erroneous, but the idea was an important departureint. The valves in a low-pressure, nonpulsatile circula-n were a source of thromboembolism and were re-ced by the direct right atrialtopulmonary anastomo-, or modified Fontan procedure (6). In its lastteration, the right heart was bypassed altogether, withextracardiac conduit steering blood from the head andfeet directly into the pulmonary artery via the superior
d inferior vena cavae (7).Thus, in Fontan patients, a circulation in series is surgi-ly re-established, but in the absence of a pulsatile sub-lmonary ventricle, blood must flow down a pressuredient from the cavae to the left atrium. Necessarily, thelmonary pressures must remain low as must the pressurethe left atrium. Under such circumstances, the goals ofFontan procedure are realized: to relieve cyanosis and to
intain cardiac output; reduce volume loading of thetemic ventricle.
2006, I was privileged to host a small group of medicaldents who had requested to visit our congenital heartease unit. I invited a patient to speak about living withlong disease. A young woman explained that she hadn planning her departure to the University of California,s Angeles, to study film when she survived a cardiac arrestd required an implantable defibrillator. She described aart-stopping experience, indicating that we had beeniting 20 years for something to go wrong. With wit, shered her existential dilemmas. The tone of the conversa-n was much like what one hears in any number of coffeeps concentrated around college campuses. I watched
th pleasure as the patient and students of the same agehanged ideas. When the meeting ended, I saw the youngmen walk down the corridor in continued discourse withe of the students. The next day, I received a call. One of
students wanted to meet with me. She walked into myce, tall with a lot of thick dark hair and large, inquisitivewn eyes. She looked fit and happy but restless. She sat
wn and pulled out of her large bag a small sealed envelopet she handed to me. By way of easing conversation, Ied her what she had enjoyed most in medicine to date.e indicated her definite desire to be a cardiac surgeon.ter a few minutes, I asked her if I could open the
doi:10.1016/j.jacc.2010.03.036velope. A single sheet of paper revealed an operativeort of the Fontan operation she underwent at 4 years of. She had not gone back to a cardiologist since the age of
152 Marelli JACC Vol. 56, No. 2, 2010years. I asked her why she came on this day. She said thatt she had been inspired by the film student she had met.patient with tetralogy of Fallot (TOF) having surviveddiac arrest thus inspired a physician in training with antan operation to become a patient again. The story isving for many reasons beyond the scope of this editorial.does, however, underscore the extraordinary motivationour work and highlight several characteristics of Fontan
tients worthy of mention.Complications and mortality vary with underlying anatomy,year of operation, and the type of Fontan anastomosis (8).
r patients operated before 1985, 10-year survival was 60% to% (9). Twenty-five-year survival was almost 80% in patientsh tricuspid atresia (10). With the more recent lateral tunnelextracardiac Fontan procedures, 10- to 25-year survival has
ied from 80% to 90% (11). Of patients undergoing thentan operation for tricuspid atresia from the 1970s to the90s, nearly 90% are in New York Heart Association func-nal class I or II on long-term follow-up (10). In thectionally single ventricle, echocardiographic indexes of sys-
ic and diastolic dysfunction are well documented (12).yond 20 years, deterioration in functional class can occuridly with the onset of complications (13).Thus, although complete bypass of the right heart in theence of a subpulmonary pump was not achievable inmals with horizontal bodies, it was realized in humans, whore vertical most of the time (14). Was it really possible forod to flow from the ankles back up to the heart without amp or heart valves (14)? Evidently yes, but what are theical consequences on the lower extremities?
e Present Study
this issue of the Journal, Valente et al. (15) address thisestion, which has not been asked to date, with thell-named CALF (Congenital Heart Disease in Adultswer Extremity Systemic Venous Health in Fontan Pa-nts) study. The investigation, driven by astute clinicalservation, describes the risk for chronic venous insuffi-ncy (CVI) in patients with the Fontan operation. Fontantients are compared with normal subjects and a group oftients with TOF repair to determine if those with thentan operation are at increased risk for CVI.The investigators performed a multicenter, prospective,ss-sectional observational study recruiting 159 stablentan patients age 18 years, 40 patients with TOF, andnormal controls. A standardized clinical examination of
lower extremities was performed using the clinical,ological, anatomical, and physiological (CEAP) classifi-ion of CVI. Severe CVI was defined as CEAP grade4.e observations were photographed to record the CEAPde. Validation was obtained in a subgroup of patients,
monstrating 100% correlation for those with severe CVIween the CEAP grade assigned by a vascular medicine
Fontan Operation: A Leg to Stand On?cialist blinded to the record and the grade determined byclinical investigators.
a dmeThe Fontan group had a mean age of 30.6 9.1 years.e single ventricle was predominantly of the left ventric-r type, and the Fontan procedures were mostly atriopul-nary anastomosis and lateral tunnel types. Of the Fontan
tients, 27% had histories of thrombotic complications.e prevalence of CVI in the Fontan population was twicet in the controls, and 22% of Fontan patients had severeI compared with none of the healthy controls. Inltivariate analysis, more than 5 cardiac catheterizations,symptoms, and deep venous thrombosis were indepen-
ntly correlated with severe CVI. The investigators ob-ved no correlation between CVI and cardiac factorssidered to be risk factors for adverse Fontan outcomes,luding the morphology of the underlying ventricle andtype of Fontan anastomosis. In all likelihood, the small
mbers preclude the ability to demonstrate specific Fontantures that would help identify the subgroup of patients ath risk for severe CVI. Furthermore, there are no reported
ta on hemodynamic or biochemical markers of throm-tic risk.The investigators postulate that as a result of a chronicallyh caval pressure, an elevation in systemic venous hydro-tic pressure may occur, inducing venous remodeling,pertension, and inflammation. In the Fontan circulation,temic venous return is closely dependant on peripheralous properties (16). In a study of 6 Fontan patients andtrols, Kelley et al. (16) measured peripheral venousssure, venous pooling, and changes in vasomotor toneder normal conditions and with the induction of gradedhostatic stress. In these patients, all of whom had residualht atrial tissue, the baroreceptor-mediated ability to limitous pooling was preserved (16). Fontan patients alsowed a smaller capacity for venous pooling and anrease in venomotor tone (16). Furthering these observa-ns, Krishnan et al. (17) investigated what effect thisght have on microvascular filtration. Using strain-gauged impedance plethysmography during the head-up tiltt in 9 Fontan patients, they documented a measurablerease in lower limb venous pressure associated with aher threshold for microvascular filtration in Fontan
tients compared with controls (17). Taken together, thesedings suggest that in Fontan patients, adaptive mecha-ms are in place to enhance the gradient for venous returnthe heart, prevent an excessive drop in systemic venousssure with orthostasis, and prevent the onset of periph-l vascular changes that would be observed in normaltients at the same venous pressures.In the group of Fontan patients reported by Valente et al.), what then differentiates the 22% of Fontan patientso exhibited severe CVI from those who did not? Is itt the elevation in systemic pressures exceeded the
aptive mechanisms seen in Fontan patients withoutI? Is it that a subgroup of Fontan patients exhibiteder filtration thresholds in their limbs? Would we find
July 6, 2010:1513ifference in those with and without residual right atrialchanoreceptor tissue in the Fontan circulation? Interest-
ingly, perhaps the answer lies not only in the peripheralFontan circulation but also in the function of the singleventricle. It is remarkable to note that in the present study(15), the prevalence of CVI was not significantly different inFontan patients and in those with TOF repair known forright ventricular dysfunction (18). There are no data in thepresent study that would allow us to speculate as to thereason for this finding. We are not provided with informa-tion on ventricular function in either the Fontan or theTOF group. If ventricular dysfunction is the final commonpathway for CVI in both patient groups, the investigatorsmay have uncovered an important finding applicable to awide range of patients with congenital heart disease withrigquconinvvenfun
2. Peto J, editor. The Heart. London: Yale University Press, 2007.3. Harvey W. De Motu Cordis 1628 (translated by Kenneth J. Franklin).
Movement of the Heart and Blood in Animals. London: Blackwell;1957.
4. Gewillig M. The Fontan circulation. Heart 2005;91:83946.5. Glenn WW. Circulatory bypass of the right side of the heart. IV.
Shunt between superior vena cava and distal right pulmonary artery;report of clinical application. N Engl J Med 1958;259:11720.
6. Kreutzer G, Galindez E, Bono H, De Palma C, Laura JP. Anoperation for the correction of tricuspid atresia. J Thorac CardiovascSurg 1973;66:61321.
7. de Leval M, Kilner P, Gewillig M, Bull C. Total cavopulmonaryconnection: a logical alternative to atriopulmonary connection forcomplex Fontan operations. Experimental studies and early clinicalexperience. J Thorac Cardiovasc Surg 1988;96:68295.
8. Khairy P, Fernandes SM, Mayer JE Jr., et al. Long-term survival,
153JACC Vol. 56, No. 2, 2010 MarelliJuly 6, 2010:1513 Fontan Operation: A Leg to Stand On?ht ventricular dysfunction. A prospective study withantitative data on ventricular function and hemodynamicditions using the method established by the CALFestigators, targeting patients with CVI who have single-tricle, systemic, and nonsystemic right ventricular dys-ction, would help answer these questions.
Four decades after the first description of the Fontaneration (1), in answer to the question of whether we ever hadg to stand on, the answer is probably no. It has been said of
illiam Harveys scientific genius that it resulted from hislity to see the implications of even rough approximation (2).ite possibly, the work of Sewell, Glenn, and Fontanoused the same cognitive course (1,5). Like many things inure, although the results are not perfect, they are no lessarkable. Fontan patients have captured the imagination of
ir surgeons and cardiologists for a long time. Valente et al.) provide a novel, thought-provoking set of observationst, as with many good studies, leave us with a new set ofestions and wanting for more answers.
print requests and correspondence: Dr. Ariane Marelli, McGillult Unit for Congenital Heart Disease, McGill University Healthntre, 687 Pine Avenue West, Room H4-33, Montreal, QuebecA 1A1, Canada. E-mail: firstname.lastname@example.org.
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y Words: Fontan y venous insufficiency y adult congenital heartase.