Unoperated Tetralogy of Fallot

A Natural Survivor Who Refused for Surgery at the Age of 42 Years – Was It Ever Too Late To Operate?

Abstract

Tetralogy of Fallot is the most common form of cyanotic congenital heart disease. Survival after the age of 12 years without corrective surgery is rare. We present a case of 42-year-old Indian male with uncorrected tetralogy of Fallot. Possible reasons for the longevity in this patient are left ventricular hypertrophy and systemic to pulmonary shunting through mediastinal collaterals.

INTRODUCTION

Tetralogy of Fallot is the most common form of cyanotic congenital heart disease, accounting for about 10% of all cases of congenital heart diseases.[¹] It consists of interventricular septal defect, right ventricular outflow tract (RVOT) obstruction, an overriding aorta, and right ventricular hypertrophy. The primary lesion is the cranial and anterior deviation of the infundibular septum, which ultimately leads to four classical alterations.[²³] The most patients experience cyanosis at birth and die in childhood without surgical intervention. Without corrective surgery, average life expectancy is of 12 years.[⁴] Epidemiological studies and autopsy records demonstrated that only 2% of all patients with tetralogy of Fallot reach the fourth decade of life,[⁵] and survival beyond the seventh decade of life is even rarer.[⁶] We present a case of 42-year-old male with uncorrected tetralogy of Fallot and right-sided aortic arch. We also review the possible factor contributing to his longevity and consider whether surgery in his 42^nd year of life would have been appropriate.

CASE REPORT

A 42-year-old Indian male patient presented with easy fatigability, breathlessness on moderate exertion (NYHA 2), and palpitations from childhood. There was no definite history of cyanotic spell or seizure disorder. There was no history of paroxysmal nocturnal dyspnea; neither was there pedal, facial, or abdominal swelling. The patient was not a known hypertensive, diabetic, or asthmatic. His body mass index was 26. There were central and peripheral cyanosis and clubbing of both fingers and toes. Pulse rate was 86/min, regular, and of moderate volume. Blood pressure was 134/82 mmHg. Jugular venous pulse was normal with the normal waveform. His apical impulse was felt in the left fifth intercostal space inside the midclavicular line. Pulsation was felt in the left parasternal region. First heart sound was normal. Second sound was single with only aortic component. There were no added sounds. A Grade 3/6 mid-systolic murmur was audible in the third left intercostal space. Neurological examination did not reveal any focal neurological deficit. Respiratory and gastrointestinal systems were within normal limits. His hematocrit was 67%, and hemoglobin was 22 g%. Serum electrolyte, urea, and creatinine were within normal limits. Chest X-ray showed boot-shaped heart and right-sided aortic arch with leftward deviation of trachea [Figure 1]. Electrocardiography showed sinus rhythm, biventricular hypertrophy with secondary ST-T wave abnormalities. Echocardiography showed a perimembranous ventricular septal defect (VSD) measuring 10 mm with bidirectional shunt, aortic override (with aortic diameter of 21 mm), septal wall thickness of 10 mm in diastole, small volume of left ventricular cavity (left ventricular end-diastolic volume of 36 ml), and left ventricular ejection fraction in supranormal limit of 73%. There was right ventricular hypertrophy with right ventricular free wall thickness of 11 mm and dilated right atrium. Severe pulmonary stenosis with peak gradient was of 72 mmHg. Cardiac computed tomography (CT) [Figure 2] done showed the features of tetralogy of Fallot. Pulmonary artery and its branches were near-normal in caliber and outline [Figure 3]. There was right-sided aortic arch, and collateral vascular channels in mediastinum were visible in cardiac CT. Three-dimensional reconstruction of cardiac CT [Figure 4] done also confirmed the pulmonary stenosis.

Figure 1: Chest X-ray showing boot shaped heart of tetralogy of Fallot, with right-sided aortic arch displacing the trachea to left side

Figure 2: Cardiac computed tomography showing overriding of aorta and ventricular septal defect of 20 mm

Figure 3: Cardiac computed tomography showing near normal caliber main pulmonary artery dividing into right and left pulmonary arteries

Figure 4: Three-dimensional reconstruction of cardiac computed tomography showing pulmonary stenosis and extracardiac anatomy very clearly

The patient was given the option for surgical correction, but he opted for medical management and hence was discharged and is in regular follow-up.

DISCUSSION

Tetralogy of Fallot first described in 1888 by the French physician Etienne–Louis Arthur Fallot is the most common congenital cyanotic heart abnormality, accounting for 10% of cardiac defects detected in infancy.[⁷] Additional anomalies occur with tetralogy of Fallot in varying frequencies, such as right aortic arch (25%), atrial septal defect (10%), and coronary anomalies (10%).[⁸] The presence of the large VSD permits the equalization of pressures across the right and left ventricles, with resultant right to left shunting and cyanosis due to higher resistance flow in the RVOT. Since the Blalock and Taussig procedure was described in 1945,[⁹] surgeons have been able to offer palliative or definitive repairs to patients from infancy to adulthood. Previously used palliative treatments have given a way in the modern era to complete surgical repair at an early age with <3% operative mortality reported in young patients.[⁸] Young patients can expect favorable outcomes, with long-term data demonstrating that 30-year actuarial survival rate for patients with corrected tetralogy of Fallot was 90% of the expected survival rate.[¹⁰]

Bertranou et al. reported survival without surgery to be 66% at 1 year of age, 40% at 3 years of age, 11% at 20 years of age, 6% at 30 years of age, and 3% at 40 years.[⁴] Since 1929, when the first report of a patient with uncorrected tetralogy of Fallot surviving into late adulthood was made,[¹¹] there have been various papers in the world literature of surprising longevity in such patients, several of whom lived into their seventh and eight decades.[¹²¹³¹⁴] Several years ago, an 86-year-old man with uncorrected tetralogy of Fallot was reported as the oldest known surviving case.[¹²] The ability of such patients to survive into senescence putatively owes to lesser degree of RVOT obstruction, leading to a well-balanced bidirectional shunt, or acyanotic left to right shunt. Yang et al. reported that unoperated survivors tend to have three common features, including a hypoplastic pulmonary artery, left ventricular hypertrophy, or systemic to pulmonary artery collaterals for pulmonary blood flow.[¹⁰] They hypothesized that these patients benefit from relatively slow development of subpulmonary obstruction. Most of our patient's findings were consistent with this physiology. The morphological features of tetralogy of Fallot are depicted well by cardiac CT, and additional anatomical details such as variant coronary anomaly and extracardiac vascular structure can be of particular importance for presurgical planning.

Determining at what age a patient's surgical risk outweighs the benefits of operating is controversial and must be made in the context of patient's clinical circumstances and patient's desire. Retrospective analysis of surgical repair in adulthood (mean age 29 years) of 52 patients with tetralogy of Fallot or pulmonary atresia and VSD documented a 15% early postoperative mortality.[¹⁵] Other studies have documented slightly lower mortality rates, and arguably, with proper population selection, improvements in functional status, and the potential for long-term survival outweighs the operative risks.[¹⁶] In addition to sudden cardiac death and biventricular failure, adults with congenital cyanotic heart disease are known to develop a compensatory erythrocytosis as a result of chronic hypoxia. The consequent elevation in blood viscosity may predispose the patient to veno-occlusive disease and cerebrovascular accidents.

CONCLUSION

Adult patients with uncorrected tetralogy of Fallot rarely live beyond the age of 40. Morbidity in these patients can stem not only from primary cardiac events, but also secondary neurological deficits incurred by their underlying disease. Along with echocardiography cardiac, CT serves as an important modality in investigating congenital cardiac anomalies, particularly in defining extracardiac anatomy.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.