Myocardial expression of heat shock protein 70i protects early postoperative right ventricular function in cyanotic tetralogy of Fallot.

BACKGROUND: Right ventricular dysfunction occurs after tetralogy of Fallot repair and may relate to greater myocardial vulnerability to ischemia-reperfusion injury in cyanotic patients. The inducible form of heat shock protein 70 (HSP-70i), a molecular chaperone, is upregulated in response to cellular stress and limits myocardial injury against ischemia-reperfusion. We evaluated the myocardial expression of HSP-70i and its relation to right ventricular function and clinical outcome in patients with tetralogy of Fallot undergoing corrective surgery. METHODS: Twenty patients with tetralogy of Fallot were studied: 10 cyanotic (group Cy) and 10 noncyanotic (group noCy). Western blot was used to quantify HSP-70i from resected right ventricular outflow tract myocardium at baseline and subsequent ischemic time. Biventricular function was quantified by tissue Doppler echocardiography and compared with that of 15 age-matched healthy children. Postoperative systemic perfusion was assessed by mixed venous oxygen saturation, oxygen extraction ratio, and lactate. RESULTS: Group Cy had thicker septum (median 0.85 vs 0.66 cm; P = .01) and longer crossclamp time (median 100.0 vs 67.5 minutes; P = .004). There were no difference in HSP-70i between groups at baseline (4.12 vs 3.44 relative optical density; P = .45) or subsequent ischemic time. Preoperative biventricular systolic function was reduced in patients with tetralogy compared with controls with further postoperative right ventricular impairment. Group Cy had higher troponin-I levels (median 16.5 vs 11.1 ng/mL; P = .04) and inotrope scores (14.0 vs 6.5; P = .05) but no differences in ventricular function, mixed venous oxygen saturation, oxygen extraction ratio, and lactate between groups. In group Cy, baseline HSP-70i correlated with better postoperative right ventricular function (rho = 0.80; P = .009), mixed venous oxygen saturation (rho = 0.68; P = .04), and oxygen extraction ratio (rho = -0.71; P = .03). These relationships were absent in group noCy. CONCLUSIONS: The association of HSP-70i expression with improved right ventricular function and systemic perfusion suggests an important cardioprotective effect of HSP-70i in cyanotic tetralogy of Fallot.

Synergistic interaction between right ventricular mechanical dyssynchrony and pulmonary regurgitation determines early outcome following tetralogy of Fallot repair.

OBJECTIVE: The ability of the right ventricle to tolerate acute pulmonary regurgitation (PR) following tetralogy of Fallot (TOF) repair is variable and the mechanisms that underlie this are not completely understood. We hypothesise that dyssynchronous wall mechanics affects the RV tolerance to postoperative PR with adverse effect on early surgical outcome. METHODS: Twenty-four TOFs (mean age 19.5+/-15.5 months) undergoing elective repair were prospectively recruited. Ventricular wall mechanics was studied by tissue Doppler echocardiography following induction (preop) and postoperative day one (POD1) and compared with a control group (10 VSD/AVSD). Segmental dyssynchrony, defined as out-of-phase peak myocardial contraction, was determined at the base, mid, apical segments of the septum, RV and LV free walls and scored by the total number of affected segments. PR was graded from absent to severe and RV dimension was quantified by end-diastolic area index (RVEDAI). Cardiac index (CI) was measured by pulse contour cardiac output analysis. Outcome measures were CI, mixed venous oxygen saturation (SvO2), lactate, and duration of ventilation and critical care stay. RESULTS: Preoperatively, biventricular free-wall motion was synchronous in both groups. Following surgery, TOF developed RV-septal dyssynchrony (>2 segments in 11 (46%) vs none in control, p=0.01), while the LV free wall remained normal in both groups. RV-septal dyssynchrony correlated with the ventilation time (rho=0.69, p=0.003), critical care stay (rho=0.58, p=0.02) in the presence of PR (n=16), but not with other outcome measures. The relationships between dyssynchrony and early outcome were not seen when PR was absent. In the presence of PR, median RVEDAI was greater with higher dyssynchrony score (>3 segments; p=0.009). The degree of PR did not affect critical care/ventilation time or RVEDAI. The presence of transannular patch (p=0.007) or at least moderate PR (p=0.01) was associated with a more severe dyssynchrony. CONCLUSIONS: Dyssynchronous RV-septal wall mechanics occurs early after Fallot repair. The magnitude of dyssynchrony appears to interact synergistically with pulmonary regurgitation to influence RV dimension and early outcome.

Current status of the Contegra conduit for pediatric right ventricular outflow tract reconstruction.

Reconstruction of the right ventricular outflow tract (RVOT) is needed in a wide variety of congenital heart diseases at the time of primary repair, or later for replacement of existing valves or conduits. Ideally, the conduit or valve needed for such reconstruction should be formed of autologous tissue that grows, resists infection, lasts for the life span of the patient, and is readily available in all sizes. Such a conduit is not available, though several alternatives have been used, none of which is without potential drawbacks. One alternative--the Contegra bovine jugular vein conduit (Medtronic, Inc., Minneapolis, MN, USA)--was introduced in 1999 and has gained widespread application, with increasing enthusiasm for its use. The Contegra conduit consists of a bovine jugular vein with an incorporated trileaflet valve. The conduit tissue is extremely pliable and offers optimal conditions for surgical handling. Moreover, the proximal tubular segment allows construction of the proximal anastomosis to the right ventricle, without the use of additional material. Increasingly, experience with the Contegra conduit is being published; hence, a literature search was conducted to evaluate available evidence on current use of the device in pediatric RVOT reconstruction.

Ascending aortic origin of a branch pulmonary artery--surgical management and long-term outcome.

OBJECTIVE: Ascending aortic origin of a branch pulmonary artery (AOPA, hemitruncus arteriosus) is a rare congenital malformation. While there have been isolated case reports, larger series, relating to long-term outcomes following surgery are few. This article analyses the surgical results of a series of nine patients, over a period of 29 years. METHODS: Between 1974 and 2003, nine patients [neonates, 6; infants, 3; male, 5; female, 4] were operated on for AOPA. Median age at presentation was 14 days (range birth to 231 days). Six [corrected] patients (group 1) had associated simple lesions like patent ductus arteriosus or right aortic arch. Three patients (group 2) had complex lesions with right ventricular outflow tract obstruction. One patient (group 2) had DiGeorge syndrome. All patients except group 2 presented with congestive cardiac failure and, in addition one had pre-operative coronary ischemia. Diagnosis was established by angiocardiography in two patients and by echocardiography in seven [corrected] The median age at operation was 28 days (range 7-365). Follow-up period ranged from 7 months to 20.5 years (median 9 years). RESULTS: All nine patients had an anomalous right pulmonary artery (RPA) arising from the proximal ascending aorta, while the left branch was of right ventricular origin. All had evidence of pulmonary hypertension or elevated right ventricular pressure pre-operatively. There was no operative mortality. Of eight patients who had direct anastomosis of the RPA to the main pulmonary artery, one required patch enlargement and another required stenting of an anastomotic stenosis. One patient had a RV-RPA conduit, which required replacement 8, 13, and 14 years later. At follow-up, all patients were alive. All patients in group 1 had normal haemodynamic function and were in NYHA class I. In group 2, all were in NYHA class II with evidence of right ventricular hypertrophy. Four patients had post-operative ventilation-perfusion scans which showed satisfactory perfusion to both lungs. CONCLUSIONS: Early surgery is indicated in this lesion and is compatible with good long-term outlook. Surgical repair should not be deferred for corrective procedures of associated cardiac anomalies.

Closure of secundum atrial septal defect in adults.

OBJECTIVE: To examine the outcome of ASD closure in adults and the effect of patient's age on drug therapy, symptoms and incidence of atrial fibrillation. DESIGN: A follow-up study. PLACE AND DURATION OF STUDY: University Department of Cardiothoracic Surgery, Glasgow Royal Infirmary, Glasgow, G31 2ER during the period 1989-1999. SUBJECTS AND METHODS Follow-up analysis of 61 adult patients (39 women) operated between 1989 and 1999 for the repair of secundum atrial septal defects. RESULTS: There were no deaths. Five patients from early in the series were lost to follow-up. Large defect size was associated with patch rather than direct closure but there was extensive crossover. Analysis by age showed that patients over 49 had more postoperative atrial fibrillation (P=0.001), more chest pain (P< 0.0001), more postoperative dyspnea (p=0.021), greater use of diuretics (p=0.020) and longer hospital stay (10.1 + 2.6 vs 8.5 + 1.6 days; p=0.007) than patients under 49. CONCLUSION: Operation for atrial septal defects in adults can be performed with no mortality and low morbidity. The age at which complications appear more frequent suggests that closer analysis of these patients is required.