Tetralogy of Fallot: influence of right ventricular outflow tract reconstruction on late outcome

Surgical repair of Tetralogy of Fallot (TOF) is followed by very good early and medium-term results (perioperative mortality < or =5%), but there is increasing awareness of the occurrence of late adverse events: many patients experience progressive right ventricular (RV) dilatation/dysfunction leading to symptomatic right ventricular failure, arrhythmias, need for reoperation(in 5-15% of patients within 5-20 years after initial correction ), and late death. Although some predisposing factors such as complexity of anatomy (borderline pulmonary artery (PA) size, right ventricular outflow tract (RVOT) hypoplasia), age at operation, or prior shunting appear to affect early or late outcome adversely, it is debatable if other factors such as type of repair or use of a transannular patch correlate with poor late outcome or increased reoperation rates. Obviously, if careful study reveals specific modifiable factors predisposing to adverse late events (e.g. component of surgical technique), appropriate modification in surgical management may lead to improved late outcome.

Extracorporeal membrane oxygenation circulatory support after cardiac surgery

OBJECTIVES

Postcardiotomy acute severe heart failure cannot be managed by medical treatment alone and most often requires some form of mechanical support. In this study we evaluate the efficacy of postoperative extracorporeal membrane oxygenation (ECMO) support following surgery for congenital heart disease (CHD) in infants and children.

METHODS

Over a 6-year period from October 1997 to October 2003, 10 patients aged 5 days to 28.5 months (median 3 months) who underwent surgical procedures for CHD received postoperative mechanical support for failing cardiac function despite optimal medical therapy. In 3 patients ECMO was instituted in the operating room (OR) and in 7 patients this was introduced in the intensive care unit (ICU) 2 to 48 (median 20) hours postoperatively.

RESULTS

Four patients (40%) were successfully weaned, while support was withdrawn in the remaining 6 due to irreversible vital organ damage. Following successful weaning, one of the survivors died 8 hours later from barotrauma and intrapulmonary hemorrhage, and another died 4 months later from persistent heart failure. The other two patients remain well in NYHA class II.

CONCLUSIONS

Despite the adverse effects of ECMO, the methodology provided the necessary support and allowed the failing heart to recover in a number of patients where inotropic support alone proved inadequate.

Early results after transatrial/transpulmonary repair of tetralogy of Fallot

OBJECTIVES

Right ventricular (RV) dysfunction is a significant cause of morbidity and mortality after surgical correction of tetralogy of Fallot (TOF). Transatrial/transpulmonary repair avoids a ventriculotomy (in contrast to the transventricular approach) emphasizing maximal preservation of RV structure and function. We have adopted this technique as less traumatic for the right ventricle. This study evaluates the early surgical results of our approach.

METHODS

Between September 1997 and July 2001, 110 consecutive patients with TOF were referred to our unit for surgical therapy. Of these, 14 were unsuitable for repair and underwent aortopulmonary shunting+/-pulmonary artery patching. In the remaining 96 patients (median age 1.4 years), complete transatrial/transpulmonary repair was performed. Previously placed shunts (ten patients) were taken down and any secondary stenoses or branch pulmonary artery distortion repaired. In all cases, subpulmonary resection and ventricular septal defect (VSD) closure were accomplished transatrially. Whenever pulmonary valvotomy and valve ring widening were necessary, it was achieved through a pulmonary arteriotomy. In 84 patients the main pulmonary artery was augmented with an autologous pericardial patch, and in 23 the patch was extended to pulmonary artery branch(es). A limited (<1cm ) or extended (>1cm, but <or=length of RV infundibulum) transannular incision was necessary in 59 and 18 patients, respectively, in order to achieve an adequate residual RV outflow tract diameter. A monocusp autologous pericardial valve was placed in 13 patients.

RESULTS

There was no death in this series. No patient required permanent pacemaker. In one case, early reoperation for residual RV outflow tract obstruction was needed. Median ICU and hospital stay were 3.5 and 10 days, respectively. At median follow up of 26 (mean 25+/-12) months, all patients are asymptomatic, with no significant residual lesion.

CONCLUSIONS

Transatrial/transpulmonary repair of TOF is associated with remarkably low morbidity and mortality in our early experience.

Nonsurgical infarctectomy in acute experimental myocardial infarction

This study examines whether a catheter mounted left intraventricular balloon may prevent left ventricular (LV) dysfunction following acute experimental myocardial infarction. In 10 anesthetized pigs, multiple coronary arterial ligations were applied around the apex of the heart. LV end-diastolic pressure (LVEDP), aortic flow (AF), and LV long and short axis fractional shortening (FS) were measured before and at 15 min intervals after ligations. At the 60th min after ligation, the LV long axis FS and AF decreased by 7.2 +/- 2.6% (p < 0.05) and 13.25 +/- 2.68% (p < 0.01), respectively, and the LVEDP increased by 4.3 +/- 1.1 mm Hg (p < 0.01) while no change was noted in the LV short axis FS. An intraventricular catheter mounted nonpulsating balloon was positioned over the endocardium of the infarcted area at the LV apex. Inflation of the nonpulsating balloon to an optimal volume, which was found to be equal to 8-10% of the LV end-diastolic volume, resulted in a reduction (by 3.8 +/- 1.2 mm Hg, p < 0.01) of the already increased LVEDP and in an increase (by 6.6 +/- 2.1%, p < 0.05) in the LV short axis FS while no statistically significant change was noted in the AF and LV long axis FS. It is concluded that an intraventricular catheter mounted balloon patch positioned over the endocardium of the infarcted area may ameliorate early LV dysfunction, possibly by interfering with the functional geometry of the LV contraction.