James L. Monro

Right ventricular function and exercise performance late after primary repair of tetralogy of fallot with the transannular patch in infancy

To evaluate the late effects of chronic pulmonary regurgitation against the putative benefits from the current surgical trend of primary repair of tetralogy of Fallot with a transannular patch in infancy, 10 patients > 10 years after early primary repair and 7 matched normal controls underwent exercise stress test and cine magnetic resonance imaging assessment of ventricular functions. Right ventricular impaired diastolic function and decreased exercise capacity, both significantly associated with pulmonary regurgitation in patients, indicated that early primary repair of tetralogy may not prevent late ventricular dysfunction and diminished exercise performance if chronic regurgitation results from right ventricular outflow tract reconstruction.

Cerebral oxygenation during paediatric cardiac surgery : identification of vulnerable periods using near infrared spectroscopy

OBJECTIVE Neurologic sequelae remain a well recognised complication of paediatric cardiac surgery. Monitoring of cerebral oxygenation may be a useful technique for identifying vulnerable periods for the development of neurologic injury. We sought to measure regional cerebral oxygenation in children undergoing cardiac surgery using near infrared spectroscopy to ascertain such vulnerable periods. METHODS Observational study of 18 children (median age 1.3 years) undergoing cardiac surgery (17 with cardiopulmonary bypass, 8 with circulatory arrest). Regional cerebral oxygenation was monitored using the INVOS 3100 cerebral oximeter and related to haemodynamic parameters at each stage of the procedure. RESULTS Prior to the onset of bypass, 10 patients had a decrease in regional cerebral oxygenation of > or = 15% points, reaching an absolute haemoglobin saturation less than 35% in 5 cases. The most common cause was handling and dissection around the heart prior to and during caval cannulation. With institution of bypass, regional cerebral oxygenation increased by a mean 18% points to a mean maximum of 75%. During circulatory arrest regional cerebral oxygenation decreased with rate of decay influenced by temperature at onset of arrest (0.25%/min at < 20 degrees C; 2%/min at > 20 degrees C). Reperfusion caused an immediate increase in regional cerebral oxygenation followed by a decrease during rewarming. Discontinuation of bypass caused a precipitous decrease in regional cerebral oxygenation in 5 patients, reaching less than 50% in 3 patients. CONCLUSIONS These observations suggest that the pre- and early post-bypass periods are vulnerable times for provision of adequate cerebral oxygenation. Near infrared spectroscopy is a promising tool for monitoring O2 supply/demand relationships especially during circulatory arrest.

Outcome after repair of tetralogy of Fallot in the first year of life

BACKGROUND The purpose of this study was to evaluate the early and late outcome after repair of tetralogy of Fallot in the first year of life. METHODS Between 1974 and 2000, 89 consecutive infants with a mean age of 6.3 +/- 2.6 months (range, 15 days to 12 months) underwent repair of tetralogy of Fallot (ventricular septal defect and pulmonary stenosis) by one surgeon (J.L.M.). Three infants had previous palliative operations. Sixty-seven procedures were urgent or emergency. A transannular patch was inserted in 69 patients (77.5%). Follow-up was complete, averaging 13.4 +/- 5.6 years (range, 0 to 25.4 years). RESULTS There was one operative death (1.1%). Mean right ventricular to left ventricular pressure ratio postoperatively was 0.4 +/- 1.1 (in 79 patients, < 0.5). Fourteen patients underwent reoperations or reinterventions. There were no reoperations for residual or recurrent ventricular septal defect. Kaplan-Meier freedom from reoperation or reintervention for any cause at 20 years was 85% +/- 4.4%, for relief of right ventricular outflow tract obstruction it was 94% +/- 3.1%, and for pulmonary valve replacement this was 95.4% +/- 2.6%. Use of a transannular patch did not significantly affect the need for reoperation or reintervention. There was one late death (leukemia). Kaplan-Meier 20-year survival was 97.8% +/- 1.9%. On latest echocardiography, 42 patients had moderate pulmonary regurgitation, 4 had a right ventricular outflow tract gradient more than 40 mm Hg, and 86 had good biventricular function. Twelve-lead electrocardiography was performed in all and 24-hour electrocardiography in 61 patients. One patient (1.1%) exhibited late recurrent ventricular tachycardia requiring implantation of a defibrillator. The remaining 86 patients are in New York Heart Association class I with none of them receiving antiarrhythmic medications. CONCLUSIONS These data strongly support the concept of early repair of tetralogy of Fallot. It is associated with an acceptable operative risk and a low incidence of significant arrhythmias, and provides long-term survival similar to that observed in the general population. Late complications may, however, develop, and long-term follow-up for their early recognition is essential.

Aortic valve replacement in children: are mechanical prostheses a good option?

OBJECTIVE The choice of the most appropriate substitute in children with irreparable aortic valve lesions remains controversial. The aim of this study was to assess early and late outcomes following aortic valve replacement (AVR) with mechanical prostheses in children. PATIENTS Fifty-six patients (42 male, 14 female, mean age 11.2, range 1-16 years) undergoing AVR with mechanical prostheses between October 1972 and January 1999 were evaluated. Thirty-six patients (64.2%) underwent previous cardiac surgery. Disease aetiology was congenital in 47 patients (congenital aortic stenosis in 33, and other congenital abnormalities in 14) (83.9%), infective in four (7. 1%), rheumatic in two (3.4%), and three (5.3%) had connective tissue disorders. Haemodynamic indication for AVR was aortic regurgitation (AR) in 24 (42.8%), aortic stenosis (AS) in 22 (39.2%) and mixed disease in ten (17.8%). Twenty-eight patients (50.0%) were in New York Heart Association (NYHA) class III-IV before surgery. Concomitant procedures were performed in 31 patients (55.3%), including aortic root enlargement in 28 (50%). The mean size of implanted valves was 22.4 mm (range 17-27 mm). All patients received long-term anticoagulation treatment with sodium warfarin, aiming to maintain an international normalized ratio (INR) between 2.5-3.0. The mean follow-up was 7.3 years (range 0-26, total 405 patient-years). RESULTS Operative mortality was 5.3% (three patients). Three patients developed complete heart block requiring pacing, two of them permanently. Late events included valve thrombosis (one), transient stroke (one), paravalvular leak of a mitral prosthesis (one), aneurysm of sinus of Valsalva (one) and pannus ingrowth (one). There was no major haemorrhagic event. Five patients required re-operation (8.9%), but none due to outgrowth of the valve. Regarding actuarial freedom from thrombo-embolism, any valve-related event and re-operation at 20 years was 93, 86.6 and 86. 4%. There were three late deaths. Actuarial survival, including operative mortality, at 10 and 20 years was 91 and 84.9%. The actuarial survival for the group of the patients with congenital AS (n=33) at 10 and 20 years was 93.5%, whereas for the children with other congenital heart problems (n=14) this was 85.7 and 64.3% (P=0. 09). At the latest clinical evaluation, 44 children were in NYHA class I and six were in class II. The mean gradient across the aortic prosthetic valve on echocardiography was 17.9 mmHg (range 0-47 mmHg). CONCLUSIONS Mechanical AVR, with enlargement of the aortic root if necessary, remains an excellent treatment option in children. It is associated with acceptable operative mortality, low incidence of late events and re-operation, and provides good long-term survival. It clearly represents a good alternative to available biological substitutes, including the pulmonary autograft (Ross procedure).

Cardiac surgery in the elderly.

OBJECTIVE There has been a gradual increase in the number of elderly patients referred for cardiac surgery. These patients present a difficult challenge, they are usually symptomatic yet at high risk for intervention. The aim of this study is to review our experience with cardiac surgery in patients aged 80 years or older. PATIENTS AND METHODS Between January 1981 and October 1997, 242 patients; 135 female, 107 male, mean age 82.8 years (range 80-95) underwent surgery on cardiopulmonary bypass in our unit. Surgery was performed on 14 as an emergency and 136 on an urgent (patient restricted to a hospital bed due to symptoms) basis. Pre-operatively 182 (75.2%) were in NYHA functional class 3 or 4. RESULTS Early mortality was 14 (5.7%). A mitral valve procedure and emergency surgery were significantly associated (P < 0.05) with an increased risk of operative mortality. Median ITU and in-hospital stay was 1 day (range 0-33) and 10 (range 6-49) days, respectively. Ninety-three percent of patients were living independently at home 2 months post-operatively. Survival (+/-SEM) is 98% complete (totals 557 patient years) and including early mortality at 1 and 5 years was 85.5+/-2.4% (n = 154), and 67.7+/-4.3% (n = 33). Survival for patients undergoing isolated aortic valve replacement (AVR) and coronary artery bypass grafting (CABG) at 5 years was 64.8+/-7.8% and 79.7+/-7.4%, respectively. Survival was significantly worse in patients undergoing a mitral procedure. Using Coxs proportional hazards model only type of operation (mitral surgery) was significantly associated with worse survival. CONCLUSION Cardiac surgery can be performed in a selected elderly population with a low operative mortality. Post-operatively elderly patients attain an excellent quality of life and survival. Emergency and mitral surgery in this group of patients is less rewarding.

Twelve year experience with the modified Blalock-Taussig shunt in neonates

Between 1978 and 1990, 53 consecutive modified Blalock-Taussig (MBT) shunts were performed on 51 neonates with cyanotic congenital heart disease using 3 mm-5 mm Gore-Tex grafts. Only 4 of these children had uncomplicated tetralogy of Fallot. The remainder had more complicated pathology requiring urgent intervention. Retrospective analysis of the acute and long term results was performed with 100% follow-up, ranging from 1 month to 12 years (mean 3 years). There were 3 (6%) early deaths (within 30 days of operation) and 17 (33%) late deaths. Of the late deaths, 2 died after further palliation, 2 died after total correction and 13 died suddenly at home. Post mortem examination of the 13 sudden deaths revealed blocked shunts in only 3. Actuarial survival at 2 years was 58%. Shunt patency at 12 months was 87% and at 2 years, 62%. No patient used their initial MBT shunt for more than 40 months. Although this shunt provides good initial palliation, there is a high incidence of late sudden death. We are also concerned about the limited life span of the shunt which partly (3/13) explains the sudden deaths. Therefore we have adopted an aggressive approach to re-study by angiography within 3 months of surgery.

Twenty‐Year Follow‐Up of Acute Type A Dissection: The Incidence and Extent of Distal Aortic Disease using Magnetic Resonance Imaging

Abstract A persistent distal false lumen (PDFL) after surgical repair of type A aortic dissection is the most important factor in determining long‐term survival. It has been suggested that changes in surgical technique reduce the incidence of distal false lumen. We report the findings of a 20‐year follow‐up (mean 5.2 years) on 87 patients who have undergone surgical repair of type A aortic dissection with all survivors undergoing magnetic resonance (MR) scanning of the entire aorta. Early mortality was 27.5%, and actuarial 5‐, 10‐, and 15‐year survival was 65%, 28% and 20% respectively. Early mortality had decreased to 18% in the last 5 years. The most common cause of late death was related to distal aortic disease, accounting for 47% of all late deaths with a peak incidence at 7–10 years after surgery. The incidence of PDFL in survivors was 72%, despite the fact that 82% of all intimal tears were resected at time of operation. Incidence was not affected by extension of the repair into the aortic arch nor by the use of the open technique or Gelatin‐Resorcine‐Formal tissue glue. In patients with a distal false lumen 6% had reached a maximum aortic diameter of 6 cm in at least one plane on MR scanning and 25% had reached 5 cm. We conclude that if dissection has extended beyond the arch at time of presentation then the choice of surgical technique does not prevent the persistance of a distal false lumen. MR scanning gives ideal anatomical and functional assessment of distal aortic disease and provides the surgeon with all the necessary information to plan the timing and indications for further surgery.

Spontaneous coronary artery dissection in a young woman resulting from an intense gymnasium “work-out”

We report on a young housewife who developed a spontaneous coronary artery dissection following unusually severe exercise. She survived an extensive anterior myocardial infarction with the help of an emergency coronary artery vein graft. This rare diagnosis must be considered when a young woman presents with an acute myocardial infarction.

When is extracorporeal life support worthwhile following repair of congenital heart disease in children

BACKGROUND Although the use of extracorporeal life support (ECLS) following repair of congenital heart defects in children is increasing, the criteria for ECLS usage in these patients is not well defined. The overall survival of such patients is disappointingly low and may depend on both the indication for support and the time at which ECLS is commenced. METHODS Between January 1993 and December 1996, 727 children underwent surgery for congenital heart defects at our institution with an overall hospital mortality of 5.8% (42 children). Nine of these children were treated with ECLS postoperatively. There were seven males and two females with a mean age of 7.2 months (range 2 weeks-3 years). Seven children could not be weaned from cardiopulmonary bypass (CPB) in the operating theatre. A further two were treated with ECLS later on during the postoperative period (commenced at 14 and 48 h). Full veno-arterial extra corporeal membrane oxygenation (ECMO) support was used in all children except one in whom a left ventricular assist device (LVAD) was used. RESULTS The median duration of support was 121 h (range 15-648 h). Four children (44%) were weaned from support and two of these are long-term survivors. Of the seven children in whom ECLS was instituted because of failure to wean from CPB, there was one long term survivor (LVAD support). Of the two patients in whom ECLS was instituted during the post-operative period there is one long-term survivor. CONCLUSIONS Weaning form ECLS and decannulation in 44% of our patients is comparable to other series of post-cardiotomy patients requiring ECLS. However, full veno-arterial ECMO instituted because of a failure to wean from CPB during corrective surgery is associated with an extremely poor outcome (zero long-term survivors in six patients).

Mitral valve replacement with mechanical prostheses in children: improved operative risk and survival.

OBJECTIVE The purpose of this study was to assess the early and late outcome following mitral valve replacement (MVR) with mechanical prostheses in children. PATIENTS AND METHODS Between 1981 and 2000, 44 consecutive children (mean age 6.8+/-4.7 years, 2 months--16 years) underwent mechanical MVR in Southampton. Twenty-three children were less than 5-years-old and nine were infants. Disease aetiology was congenital in 37, rheumatic in four, infective in two and Marfans syndrome in one. Mitral regurgitation was present in 36 and mitral stenosis in eight. Concomitant procedures were performed in 13, including aortic valve replacement (AVR) in seven. Follow-up was complete (mean 6.4+/-4.8 years, 1 month--18.1 years). RESULTS The overall operative mortality was 14% (six patients). Before and after 1990 operative mortality was 31 vs 3.6% (P=0.02). From 1990, operative mortality for infants was zero out of six, for children less than 5-years-old was one out of 16 (one death after emergency AVR and MVR) and for older children it was 0/12. Seven children experienced valve or anticoagulation treatment-related events and eight had a mitral valve re-operation. Ten-year freedom from thromboembolism, prosthetic valve infection, bleeding, paravalvular leak and a mitral valve re-operation was 92.8+/-5.2, 97.3+/-2.7, 97.7+/-2.3, 97.2+/-2.7 and 75+/-9.7%, respectively. Overall 10-year survival was 78+/-7% (four late deaths); for children under vs over 5 years it was 61+/-11 vs 95.2+/-4.6% (P=0.02), for atrio-ventricular septal defect (AVSD) vs other pathology 55+/-15 vs 89+/-6.1% (P=0.05) and for those operated before 1990 vs after 1990 it was 63+/-8.1 vs 86+/-8.2% (P=0.04). CONCLUSIONS Mechanical MVR, in the current era, carries a low operative risk across the spectrum of paediatric age. Late survival is better for older children and those having no-AVSD pathology but it has improved substantially during the 1990s irrespective of age and disease aetiology.