The application of the advances made in congenital cardiac surgery over the past 50 years now make it possible for a significant number of children born with congenital cardiac disease to survive into adulthood. In developed countries, mortality is currently reported more in adulthood than in childhood. This is however not the case in some developing countries where cardiology and cardiac surgery services do not abound. The West African sub-region is not endowed with well-resourced cardiac centres. There are no dedicated paediatric cardiac centres in the sub-region; first time presentation of congenital cardiac disease beyond the early years of life is the rule rather than the exception. In addition, the lack of health insurance cover for cardiac surgery in the sub-region creates a formidable obstacle for many families affected by congenital cardiac disease. Accordingly, most adolescents and adults with congenitally malformed hearts have had no form of surgical attention in childhood. Ghana’s National Cardiothoracic Centre at the Korle Bu Teaching Hospital receives referrals from several countries in the West African sub-region. This study was undertaken to review the spectrum and surgical outcome of adolescents and adults with congenitally malformed hearts referred for surgery at the centre from January, 1993 to December, 2008.
Patients and methods
Study setting
This study was undertaken at our institution, the only tertiary referral centre in the country for cardiothoracic surgical problems. Adult cardiologists evaluate paediatric and adult cardiac referrals to the centre. Diagnostic catheterisations in adults and older children are performed but catheter-based therapeutic interventions are not part of the service delivery as yet. Congenital cardiac surgery is performed together with surgery for acquired adult cardiac disease by the same set of surgeons. The same team of cardiologists and surgeons are responsible for the care of adolescents and adults with congenitally malformed hearts. The Centre also collaborates with other specialists in the care of adolescents and adults with congenitally malformed hearts hospitalised for non-cardiac indications.
Patient selection
This retrospective study included all patients 16 years and older who underwent surgery for congenital cardiac disease within the study period. Assessment of pulmonary hypertension and operability in shunt lesions was carried out clinically and by using imaging studies. The mainstay of evaluation of pulmonary hypertension in shunt lesions was trans-thoracic echocardiography. For patients with clinical and echocardiographic indicators of significant pulmonary hypertension, further evaluation involved right heart catheterisation for determination of pulmonary vascular resistance and reversibility of pulmonary hypertension using inhaled 100% oxygen. Only patients with pulmonary vascular resistance in the operable range (less than eight Wood units) were referred for surgery and therefore included in this study.
The case notes and operative records of the selected patients were reviewed. Statistical analysis was performed using Statistical Package for Social Sciences version 16.0. Results are expressed as mean plus or minus standard deviation.
Results
In the study period, a total of 586 patients of all ages underwent surgery for congenital cardiac disease; 135 (23.0%) of them met the inclusion criteria for this study of which 23 (17%) were non-Ghanaian West Africans.
There were 63 males and 72 females (M:F = 1:1.4 or 53.3% females). Their ages ranged from 16 to 70 years (Fig 1) with a mean age of 28.6 plus or minus 10.3 years (median 27 years). The mean follow-up was 7.5 plus or minus 4.4 years (median 7.6 years). Follow-up was 96.3% complete. Age and gender differences regarding the specific lesions are shown in Table 1.
Figure 1 Age distribution of adolescents and adults with congenitally malformed hearts.
Table 1 Spectrum and surgery of adolescents and adults with congenitally malformed hearts.
VSD, ventricular septal defect; ASD II, oval fossa-type atrial septal defect; TOF, tetralogy of Fallot; PDA, patent arterial duct; AVSD, atrioventricular septal defect; LVOT, left ventricular outflow tract; SAS, subvalvar aortic stenosis membranous; PAPVC, partial anomalous pulmonary venous connection; DORV, double outlet right ventricle; AVR, aortic valve replacement; PTFE, polytetrafluoroethylene; NA, not applicable
The diagnostic profile of patients less than 16 years old was similar to that of the selected patients – ventricular septal defects, oval fossa type atrial septal defects, Fallot’s tetralogy, and patent arterial ducts accounted for 85.7% of the cases coming to surgery.
Preoperative state
Preoperative evaluation consisted of patient history, physical examination, and investigative studies; transthoracic echocardiography was the mainstay of diagnostic evaluation. Using the New York Heart Association functional classification, 31 (23%), 78 (58%), and 26 (19%) patients were in functional classes I, II, and III, respectively. Patients in functional class I consisted of those with patent arterial ducts (38.7%), ventricular septal defects (35.5%), oval fossa type atrial septal defects (22.6%), and partial anomalous pulmonary venous connection (3.2%). Patients in functional class II consisted of those with atrial septal defects (24.4%), ventricular septal defects (23.1%), patent arterial ducts (14.1%), Fallot’s tetralogy (11.5%), valvar and subvalvar pulmonary stenosis (10.3%), partial atrioventricular septal defects (6.4%), left ventricular outflow tract pathology (5.1%), aortic coarctation (3.8%), and partial anomalous pulmonary venous connection (2.5%). Patients in functional class III consisted of those with Fallot’s tetralogy (57.8%), ventricular septal defects (15.5%), valvar and subvalvar pulmonary stenosis (11.5%) and 3.8% each of aortic coarctation, double outlet right ventricle, left ventricular outflow tract pathology, and partial atrioventricular septal defect.
In 14 (10.4%) patients, the cardiac defects were discovered incidentally during investigation of another illness, anaesthetic evaluation for non-cardiac surgery or during pre-employment or pre-enrolment medical examination.
Indications for surgery
Surgery was recommended largely on the basis of symptoms and the absence of contraindications such as irreversible pulmonary hypertension.
For patients with Fallot’s tetralogy, a preliminary shunt was offered to those with unfavourable anatomy (tetralogy with pulmonary atresia or severely hypoplastic pulmonary arteries), those with preoperative severe right ventricular dysfunction and indigents unable to afford complete repair. It is our institutional preference to offer a preliminary shunt for tetralogy patients with severe cyanosis (haematocrit of more than 60%) because of problems with availability of blood products, the requirements of which are increased after total repair of tetralogy with severe cyanosis.
For asymptomatic patients, surgery was recommended based on the presence of ventricular volume overload for shunt lesions or significant pressure gradients for obstructive lesions on echocardiographic assessment.
Intra-operative findings and management
Intra-operative diagnoses are shown in Table 1. Ventricular septal defects were all restrictive and less than 50% of the aortic valvar diameter. All except two, one sub-pulmonary and one muscular, were peri-membranous in location. They were all closed using glutaraldehyde-treated autologous pericardium. All six patients who underwent total repair of Fallot’s tetralogy received trans-annular patching with autologous pericardium. Pulmonary stenoses were of combined valvar and sub-valvar pathology. Infundibular resection and outflow tract patch was used in all 11 patients. All the atrioventricular septal defects were of the partial variety and repair was performed using autologous pericardium.
Corrective surgery was undertaken in 117 (86.7%) patients; the rest had palliative procedures (Table 1). All cases requiring cardiopulmonary bypass were approached through a median sternotomy; one female patient however had a right anterolateral thoracotomy for closure of oval fossa type atrial septal defect. A left 4th interspace posterolateral thoracotomy was used for repair of coarctation and for ligation of patent arterial duct. All coarctation repairs were performed using polytetrafluoroethylene patch aortoplasty.
All palliative operations were undertaken in patients with Fallot’s tetralogy and consisted of a modified Blalock–Taussig shunt in 17 patients and a Waterston’s shunt in one patient. A staged repair was adopted for most tetralogy patients. It was the usual observation, however that satisfactory palliation in this patient cohort resulted in several years of symptom-free survival and default in clinic attendance; some patients actually declined total repair following a satisfactory palliative shunt. The commonest reason these patients gave for failure to attend follow up clinics was inability to raise funds for the total repair reinforced by a state of apparent well-being. Of the six patients who underwent total repair of tetralogy of Fallot, three were repaired primarily, while the other three were repaired after a preliminary shunt.
There were six (4.3%) reoperations, all in tetralogy of Fallot patients; three were for total repair of previously palliated patients, two were further palliations with modified Blalock–Taussig shunts. The last one was for closure of a residual ventricular septal defect 4 months after total repair of tetralogy of Fallot.
Outcome
Early (30-day) mortality
A total of four (3%) early deaths occurred in this study. One was a 27-year-old female who had tetralogy of Fallot and died 6 hours after total repair from low cardiac output syndrome due to severe right ventricular dysfunction.
The second patient was a 23-year-old female who underwent ventricular septal defect closure and died in the third postoperative week from late cardiac tamponade. This occurred 19 days after closure of ventricular septal defect. The patient had been discharged home on the 10th postoperative day after an uneventful recovery, but was rushed back to the Intensive Care Unit 9 days later in cardiogenic shock. Resuscitation was unsuccessful and the patient died a few hours later. The autopsy showed accumulation of about 0.5 litre of serous pericardial fluid causing cardiac tamponade and death.
The third patient was a 17-year-old female who underwent resection of a subvalvar aortic membrane and aortic valvar replacement. Her preoperative left ventricular function was poor – ejection fraction of 37%; she died on the 18th postoperative day from progressive left ventricular failure and intractable supraventricular arrhythmias.
The fourth patient, a 17-year-old female, underwent a modified Blalock–Taussig shunt for Fallot’s tetralogy; her pulmonary arteries were severely hypoplastic (approximately 3 millimetres). Preoperative oxygen saturation ranged between 55 and 59%. Postoperative oxygen saturation remained suboptimal (80% on the average) and she expired 12 hours postoperatively without fully recovering from anesthesia.
Late death
Two late deaths (1.5%) occurred giving a linearised rate of 0.2% per patient-year. One was in a 21-year-old female who had coarctation repair. She died suddenly at home 13 months after the coarctation repair from an aortobronchial fistula. The autopsy revealed exsanguinating haemorrhage into the airway from a false aneurysm at the coarctation repair site. The aneurysm had eroded into the left main bronchus.
The second late death occurred in a 29-year-old female who underwent total repair of a ventricular septal defect, atrial septal defect, and pulmonary stenosis (valvar and infundibular). She suffered a cerebral thromboembolic event, ostensibly from supraventricular arrhythmia, 3 weeks postoperatively and was left with a permanent neurologic deficit. She died at home 2 years later from undetermined causes.
Postoperative complications
Postoperative complications occurred in 13 (9.6%) patients – bleeding, two patients, low cardiac output syndrome, three patients, residual ventricular septal defect, three patients, and delayed wound healing, four patients.
Two patients who had Fallot’s tetralogy were explored for postoperative bleeding within 24 hours of surgery. One had undergone total repair and the other had a palliative shunt. In the first patient, no discrete source of bleeding was found on exploration. The chest tube site was responsible for the postoperative bleeding in the other.
Low cardiac output with high inotropic requirements occurred in three patients; two after total repair of Fallot’s tetralogy and the third after repair of pulmonary stenosis and ventricular septal defect. Two of these eventually recovered and were discharged from hospital. The third succumbed 10 hours after total repair of Fallot’s tetralogy.
Of the three patients who had a residual ventricular septal defect, only one required a return to the operating room for ventricular septal defect nearly 4 months later; in the others, the residual defects were less than 3 millimetres in size and haemodynamically insignificant.
Delayed wound healing occurred in four patients after modified Blalock–Taussig shunt for tetralogy of Fallot. The dermal layers of the posterior end of the thoracotomy took extra 5–7 days to heal after removal of stitches on the 10th postoperative day in these four patients.
Functional improvement
Apart from four patients (including one early death) with tetralogy of Fallot who showed marginal benefit after surgery, the remainder of the patients (128 of 131 or 95%) improved by at least one functional class within the first postoperative year. Unfavourable anatomy (Fallot’s tetralogy with pulmonary atresia undergoing a shunt), restrictive right ventricular physiology and permanent neurological deficit (after repair of ventricular and atrial septal defects and pulmonary stenosis) accounted for the marginal benefits observed.
Discussion
The spectrum of adolescents and adults with congenitally malformed hearts in West Africa
Less than 20% of children born with congenital cardiac disease survived into adulthood in the presurgical era.Reference MacMahon, McKeown and Record1 Subsequent advances in paediatric cardiology and cardiac surgery have ensured the survival into adulthood of 70–80% of children born with cardiac disease.Reference Somerville2 Recognition of the emergence of this new population of adolescents and adults with congenitally malformed hearts and their peculiar problems has led many developed countries to establish dedicated centres to optimise the care of these patients. Many developing nations are still struggling to appropriate modern paediatric cardiology and cardiac surgery. This is particularly so in Africa where thousands of children with untreated but correctable cardiac defects die each year because they live in poor countries.Reference Hewitson, Zilla and Lawrenson3 In these countries, survival of children with congenital cardiac disease into adulthood may be closer to that observed in the presurgical era. The spectrum of cases seen in our study is an indication of this fact. In centres dedicated to the care of adolescents and adults with congenitally malformed hearts, reoperations for complications or residual lesions of repaired complex congenital cardiac disease create a large demand on cardiac surgical services.Reference Dore, Glancy, Stone, Menashe and Somerville4 In contrast, in developing countries including those of West Africa, the attrition of children with the more complex congenital cardiac lesions creates a spectrum of less complex lesions and relatively fewer reoperations.Reference Hannoush, Tamim and Younes5 Accordingly, in our study, ventricular septal defects, atrial septal defects, Fallot’s tetralogy, and patent arterial ducts accounted for 77.8% of the cases; reoperations were performed in only six (4.3%) patients. The representation of Fallot’s tetralogy (17.8%) in this study is noteworthy for although unrepaired tetralogy in adults is a relative rarity in the developed world, it is common in developing countries as our data indicates.
Economics play a central role in this scenario. We determined from our database that only 20% of the parents of children (less than 15 years old) requiring surgery for congenital cardiac disease are able to finance the operation within 12 months of diagnosis. On a larger scale, of the 16 countries in the West African sub-region, 12 are included in the category of least-developed countries and facilities for regular open-heart surgery exist in only four countries. Cardiac surgery, unless supplied free by visiting teams or funded by benevolent individuals or organisations, is out of the reach of the largely indigent population in this sub-region. On this basis, the spectrum of adolescents and adults with congenitally malformed hearts coming to surgery in our study is not unexpected.
The marked female preponderance in those with atrial septal defects (73.1%) and patent arterial duct (72.7%) may be a reflection of the gender distribution of these lesions at birth. OthersReference Engelfriet, Boersma and Oechslin6 have reported similar female predominance with regard to the oval fossa type of atrial septal defects.
In 14 (10.4%) patients, the diagnosis of congenital cardiac malformation was made incidentally. This occurred during investigation of an unrelated illness, anaesthetic evaluation for non-cardiac surgery or during pre-employment or pre-enrolment physical examination. Perfunctory clinical evaluations especially in asymptomatic adolescents and adults for pre-employment or pre-enrolment purposes must be avoided bearing in mind the potential for congenital cardiac malformations in such settings.
Mortality
The overall early mortality in this study was 3% (4 of 135), half of which is attributable to Fallot’s tetralogy. Berdjis et alReference Berdjis, Brandl and Uhlemann7 reported an overall operative mortality of similar magnitude (6/200 = 3%), half of which was also due to cyanotic congenital cardiac disease dominated by Fallot’s tetralogy. The adult with tetralogy thus represents a significant operative risk. The reasons are multifactorial – the chronic effects of cyanosis, severe right ventricular dysfunction at presentation, lack of adequate myocardial protection during cardiopulmonary bypass (excessive return due to collateral circulation), and muscle resection on an “ageing” right ventricle.Reference Bisoi, Murala and Airan8 Other contributing factors include renal impairment and a bleeding diathesis. In our series, severe right ventricular dysfunction and a failed modified Blalock–Taussig shunt were responsible for the deaths in the tetralogy patients.
Late cardiac tamponade was responsible for one late death. Although early cardiac tamponade (before postoperative day 15) following cardiac surgery is well recognised, late cardiac tamponade (occurring after postoperative day 15) is usually underestimatedReference Meurin, Weber and Renaud9, Reference Kuvin, Harati, Pandian, Bojar and Khabbaz10 and its clinical presentation is often atypical.Reference Tsang, Barnes and Hayes11, Reference Price, Prout, Jaggar, Gibson and Pepper12 The possibility of late tamponade should be considered in postcardiac surgery patients presenting with cardiovascular collapse unresponsive to the usual resuscitative methods.
Aortobronchial fistula caused one late death. This is a uniformly fatal complication if not surgically treated promptly. It is a recognised but rare late complication following coarctation repair.Reference Posacioglu and Apaydin13 Surgical intervention is followed by an 82% survival rate.Reference Demeter and Cordasco14
Morbidity
Postoperative bleeding requiring exploration occurred in two cases in this study. All were in patients with Fallot’s tetralogy. The peculiar susceptibility of tetralogy patients to postoperative bleeding relates to the presence of abundant collateral vessels in the mediastinum and chest wall and the coagulopathy of chronic cyanosis. Chronic cyanosis and tissue hypoxia is believed to underlie the delayed wound healing observed in tetralogy patients.
The role of palliative shunts in developing countries
In the last two decades, the good outcome of early primary repair of Fallot’s tetralogy has caused a shift from staged to primary repair regardless of age. Our institutional policy is in transition; children with Fallot’s tetralogy are repaired either primarily or following a preliminary shunt. In developing countries, the decision to undertake a palliative or corrective procedure in the patient with tetralogy is influenced not only by the centre’s resources but also by patient-dependent socio-economic factors.Reference Antunes15 We adopted a staged approach to repair Fallot’s tetralogy in adolescents and adults and found that most (16 of 24 or 66.7%) of the patients successfully palliated did not return for total repair largely on economic grounds and an apparent feeling of well-being after palliation. A 31-year-old female patient in this study achieved two successful pregnancies within 5 years of receiving a modified Blalock–Taussig shunt. The modified Blalock–Taussig shunt provides a reliable pathway for increasing pulmonary blood flow and relieving cyanosis in the adolescent and adult with Fallot’s tetralogy. Within the context of socio-economic restrictions so prevalent in most developing countries, the modified Blalock–Taussig shunt may be offered as destination therapy to the adolescent and adult with Fallot’s tetralogy or it may be used to provide considerable symptomatic relief until total repair is economically accessible.
Conclusion
In this study, the majority (36.3%) of adolescents and adults with congenitally malformed hearts coming to surgery are in their 30s. Ventricular septal defects, oval fossa type atrial septal defects, Fallot’s tetralogy, and patent arterial duct together account for the majority (77.8%) of malformations coming to surgery in this patient population. Surgical treatment is feasible in the sub-region with low mortality and acceptable morbidity. Practitioners must be mindful of the asymptomatic adult with congenital cardiac disease during physical examinations.
