Paul A. Hutter

Fate of the aortic root after arterial switch operation

OBJECTIVE Concerns have been voiced about possible dilation and insufficiency of the neo-aortic valve after the arterial switch operation (ASO). AIMS To determine growth of the neo-aortic valve and the aortic anastomosis after ASO and the prevalence of insufficiency or stenosis. PATIENTS AND METHODS Since 1977, 144 consecutive patients (pts) underwent ASO for transposition of the great arteries (TGA). Median follow-up was 8.65 years (0.1--22.5 years). Simple TGA was present in 97 pts and 47 had TGA with ventricular septal defect (VSD). Detailed echocardiography included measurements of aortic diameter at four levels. The 608 measurements were compared with published normal values. RESULTS The mean aortic valve z-score was 1.5, without significant change with age (P=0.75). Under 4 months, mean valve z-score was 0.63+/-2.20, between 5 and 12 months 2.56+/-2.30 (P<0.0001). Gradual growth occurs thereafter. The aortic sinus follows an identical growth pattern. The aorta at the anastomosis, is initially smaller than normal (z-score -0.64). After 4 months the z-score is 0.83, followed by continued growth of 0.1 z-score per year. At the last visit, the aortic valve z-score was above 2 in 51 patients, between -2 and 2 in 72 and less than -2 in six patients, none of whom had a flow velocity above 2 m/s. z-score of patients with VSD remained above those without VSD (P<0.0001). Aortic insufficiency was grade 2/4 in three patients, grade 3/4 in one and grade 4/4 in one. No patient developed aortic stenosis. CONCLUSION After ASO the neo-aortic valve and sinus are larger than normal, representing the natural size difference in the prenatal situation and influence of associated cardiac malformations. In the first year of life, rapid dilatation of the new aorta is observed, followed by growth towards normalization of the valve and sinus size. Stenosis at the anastomosis was not observed. Aortic dilatation by itself is rarely associated with significant insufficiency.

Air Travel and Adults With Cyanotic Congenital Heart Disease

BACKGROUND Concern has been expressed that a reduction of partial oxygen pressure during flight in commercial aircraft may induce dangerous hypoxemia in patients with cyanotic congenital heart disease. METHODS AND RESULTS To evaluate the validity of this concern, the transcutaneous SaO2 was measured in 12 adults with this type of heart disease and 27 control subjects during simulated commercial flights of 1.5 and 7 hours in a hypobaric chamber. Ten of those patients and 6 control subjects also were evaluated during two actual flights of approximately 2.5 hours in a DC-10 and an A-310, respectively. During the prolonged simulated and actual flights, the capillary blood pH, gases, and lactic acid were analyzed in the patients and during one of the actual flights also in the control subjects. During the simulated flights the SaO2 was at all times lower in the patients than in the control subjects. However, the maximal mean actual percentage decrease, as compared with sea level values, did not exceed 8.8% in either patients or control subjects. During the actual flights, this maximal decrease in the patients was 6%. In-flight reduction of the capillary PO2 was considerable in the control subjects but not in the patients. It is our hypothesis that the lack of a significant decrease of the PO2 in the patients might possibly be due to a high concentration of 2.3 diphosphoglycerate in the red cells. The flights had no influence on the capillary blood pH, PCO2, bicarbonate, or lactic acid levels in either patients or control subjects. CONCLUSIONS Atmospheric pressure changes during commercial air travel do not appear to be detrimental to patients with cyanotic congenital heart disease.

Influence of coronary anatomy and reimplantation on the long-term outcome of the arterial switch

BACKGROUND Abnormal coronary artery anatomy is reported to have a significant influence on the outcome of the arterial switch operation. This study examines the impact of coronary anatomy and the occurrence of late coronary obstruction on left ventricular (LV) function and long-term outcome. METHODS Coronary artery anatomy, of 170 patients after arterial switch operation (1977-1999), was determined based on operative reports and pre-operative aortograms. Current status was evaluated using ECGs, echocardiograms, scintigraphy, and post-operative coronary angiograms. RESULTS In 133/170 patients, coronary artery anatomy consisted of an anterior descending (LAD) and circumflex artery (Cx) from the left sinus and the right coronary artery (RCA) from the right or posterior sinus. The left coronary had an intramural initial course in two of these patients. Fifteen patients had the LAD from the left and Cx and RCA from the right sinus; eight had LAD and RCA from one sinus and Cx from the other; four had single ostium; and three had three separate ostia. Four patients had complex patterns and four patients had a supra commissural coronary. To date, follow-up angiography was performed in 59 patients. Surgical coronary sequellae were found in five patients. Two patients had an occluded left ostium. Initially, they were asymptomatic but showed polymorphic ventricular extrasystoles on ECG and moderate LV dysfunction with large irreversible perfusion defects on scintigraphy. Both patients developed ventricular fibrillation at the age of 14 years. One patient did not survive. The other patient required implantation of a defibrillator. One patient has an occluded RCA, one patient has stenosis of the right ostium and one patient has multiple tortuous collaterals without obstruction of a major branch. In the latter three patients, coronary sequellae were not suspected on ECG, echo, or scintigraphy and were only found on follow-up angiography. Retrograde collateral flow was noted in all three occluded coronaries. LV dysfunction, with normal coronaries, was noted in three patients. All, of these patients, had peri-operative ischaemia suggesting failure of myocardial protection. Two are now asymptomatic with mild LV dysfunction. One patient continues to have severe myocardial dysfunction and secondary aortic insufficiency. A Ross-like procedure was performed placing the original aortic valve in the neo-aortic root. Coronary artery anatomy did not influence early survival or late coronary sequellae. CONCLUSION Abnormal coronary anatomy was not a determinant of outcome in our study. Surgical coronary obstruction is independent of original anatomy. It can be almost silent and is potentially fatal. Follow-up angiography must be considered in all patients after the arterial switch operation.

Late re-interventions following arterial switch operations in transposition of the great arteries*Incidence and surgical treatment of postoperative pulmonary stenosis

Seventy-six patients were studied after arterial switch operation (ASO) between May 1977 and February 1992. Pulmonary artery reconstruction was initially performed by: conduit interposition in 5 patients, direct main pulmonary artery anastomosis and button patches in 60 patients, and pantaloon-like patch repair in 11 patients. Pulmonary stenosis developed in 17 patients (22%), requiring a total of 26 late re-interventions. Re-intervention was required in four out of five patients operated with pulmonary artery conduits, 11 out of 60 with a button patch repair and 2 out of 11 following pantaloon-type repair. In this series pulmonary artery stenosis (PS) involving the pulmonary valve occurred in 9/17 patients. Involvement of the pulmonary valve was related to the technique of pulmonary artery reconstruction. In these patients surgery is necessary. Balloon angioplasty can be a valuable tool when the stenosis is more distal. The incidence of PS was not influenced by the type of reconstruction or the use of Lecomptes maneuver.

Switch back: Using the pulmonary autograft to replace the aortic valve after arterial switch operation ☆ ☆☆ ★

Aortic valve insufficiency has been described to occur after the arterial switch operation. Valve insufficiency is mild in most cases. In some patients valve repair or root reconstruction may solve the problem, but in others the valve will have to be replaced. Inasmuch as the number of patients surviving the arterial switch operation is growing, valve insufficiency may be seen more often. In infants the ideal way to replace the aortic valve is by using a pulmonary autograft. Our experience with aortic valve replacement using a pulmonary autograft (former aortic valve) in one infant with a history of arterial switch operation is described. Clinical summary. A little girl, 3 years 4 months old, was referred to us from another institution. At the age of 2 days an arterial switch operation was performed for simple transposition of the great arteries. The coronary anatomy was normal (1LCx-2R, Leiden classification). 1 The aorta was anterior to the pulmonary artery. Both semilunar valves were tricuspid and normal. The coronary arteries were excised together with U-shaped aortic wall buttons and implanted in the pulmonary artery base by means of the trapdoor technique. The neopulmonary root was reconstructed with a pantaloon-shaped patch of autologous pericardium. A Lecompte maneuver was part of the procedure. The postoperative course was complicated by ischemia, frequent ventricular extrasystoles, and periods of ventricular fibrillation. Left hemidiaphragmatic paresis necessitated later diaphragmatic plication. After an extended period of intensive care, she gradually recovered and finally was discharged from the hospital. Progressive dilatation of the aortic root with valvular insufficiency was observed during follow-up. Insufficiency was considered to be significant (2/4) when she was 1 year old. The left ventricle was dilated. Her condition deteriorated gradually, leading to fatigue on slight exertion.

Arrhythmias after surgical correction of complete transposition—follow-up into adolescence

The long-term natural progression of cardiac rhythm and the incidence of serious arrhythmias in relation to previous procedures and associated heart defects were studied in a group of 76 patients after an arterial switch operation for complete transposition and compared to a group of 24 patients who had undergone intraatrial corrections (Mustard or Senning operation). Standard and 24-hour ambulatory electrocardiograms were reviewed. Mean follow-up was 7.9 years (range 2-16) after an arterial switch and 15.2 years (range 6-26) following the Mustard or Senning procedures. One patient died after an arterial switch from pulmonary hypertension (age 9.9 years), and three patients died suddenly, presumably from arrhythmias, following atrial redirection procedures (ages 13, 18 and 20 years). Symptomatic arrhythmias were not seen after the arterial switch operation. Three patients required pacemaker implantation after atrial redirection, and a further two required medication to control tachyarrhythmias. Survival analysis of sequential electrocardiograms showed a mean maintenance of sinus rhythm during 12.9 years (95% confidence interval 11.4-14.5) after the arterial switch and 9.0 years (7.3-10.7) after atrial procedures (p=0.003). Development of heart rate was significantly different (p=0.001), with higher rates in adolescents after an arterial switch. Twenty-four-hour recordings were abnormal in five of 72 patients following arterial correction, disclosing excessive ventricular extrasystoles in four (three monomorphic, one polymorphic) and a wandering pacemaker in one. After atrial procedures, 11 of 19 were abnormal (p

Supra pulmonary stenosis after arterial switch operation for transposition of the great arteries

Up until 25 years ago, the mortality rate of untreated transposition of the great arteries was about 90% during the first year of life. The Rashkind balloon atrio-septostomy [5], introduced in 1966, increased effective flow in both circulations and, therefore, diminished cyanosis. This decrease in cyanosis was associated with a significant decrease in the mortality rate. However, the blood exchange at atrial level does not keep up with the increasing flow dimension of children during growth. The Mustard operation, which establishes an atrial switch [4] was developed, and proved to have a low operative mortality rate; it also allows a total separation of pulmonary and systemic circulation. The atrial switch remained, therefore, the operation of choice in the following two decades. Initial enthusiasm for this operation, however, subsided when complications such as obstruction of the venous pathways, arrhythmias, and right-ventricular dysfunction caused a staggering increase in late mortality. The development of the arterial switch operation [1] suggested a new surgical treatment for patients with transposition of the great arteries without the previously stated severe complications.