Incidental Diagnosis After a Car Accident

Abstract

Tetralogy of Fallot (TOF) is a heterogeneous congenital heart disease that is occasionally diagnosed during adulthood. However, although they are often asymptomatic, adult patients with uncorrected TOF often have a poor prognosis. Poor outcomes indicate the importance of the identification and management of these patients, especially in the context of intercurrent disease or noncardiac surgery. We describe a case of clinically silent TOF in a 51-year-old woman. TOF was unmasked during a major noncardiac surgery for a polytrauma and successfully treated with the cooperation of a multidisciplinary team. (Level of Difficulty: Advanced.)

A 51-year-old woman presented to the emergency department with polytrauma after a car accident, as the pedestrian victim who was hit while crossing the road.

Learning Objectives

• •To achieve awareness of atypical presentations of uncorrected CHD in adulthood.
• •To understand the underlying pathophysiological mechanism and its impact on the management of these patients.

Vital signs and physical examination on admission documented a heart rate of 82 beats/min and blood pressure of 90/60 mm Hg; no heart murmurs or signs of pulmonary congestion were reported.

Neurologic examination and state of consciousness were normal. She underwent immediate total body computed tomography (CT) scan, which revealed multiple costal and vertebral fractures; bilateral lung contusion; a displaced fracture of the distal part of the left humerus bone, of the acetabulum and left femur; and a detachment of the left renal calyx. She underwent emergency intervention of ureteral stenting and leg fracture fixation with an intramedullary nail.

While the orthopedic procedure was performed, the patient experienced transient hypotension and subsequent severe desaturation despite ventilation with maximal oxygen concentration. The patient had an unremarkable past medical history.

Differential Diagnosis

Due to suspected pulmonary fatty or thrombotic embolization, a dedicated pulmonary CT scan was performed immediately after the intervention. Interstitial edema and partial atelectasis of the inferior pulmonary lobes were observed. Moreover, enlargement of the ascending aorta (37 mm) and hypertrophy and dilatation of the right heart chambers were indicated (Figures 1A and 1B), the latter being confirmed by the QRS axis at 102 degrees as seen in the electrocardiogram (Figure 2). In the following hours, repeated episodes of sudden desaturation and hypotension were observed, and the patient required hemodynamic support with high-dose inotropes and vasopressors (norepinephrine 1 μg/kg/min). After the care team provided a report on the patient’s critical condition, her relatives remembered that the patient had been diagnosed during childhood with a complete atrioventricular canal defect; however, her parents had refused surgery. Moreover, the family reported that the patient was asymptomatic in her daily activity, with modest dyspnea only in case of uphill walking. Therefore, being convinced of having no treatment option and without complaint of severe symptoms or limitations, she did not seek any medical evaluation during adulthood. No cognitive disability or syndromic disorder was reported. Only at the time of the accident was cardiovascular evaluation required.

Figure 1.

Angio-Computed Tomography Scan

Pulmonary embolism was excluded, showing the enlargement of the ascending aorta (37 mm, ∗) and hypertrophy and dilatation or the right heart chamber (A, arrow) and interstitial pulmonary edema with atelectasis of the inferior lobes (B, dashed arrow).

Figure 2.

Electrocardiogram at Admission

Investigations

It was not possible to perform transthoracic echocardiogram because of subcutaneous emphysema.

A transesophageal echocardiogram was then performed and revealed a displacement and enlargement of the right chambers, biventricular hypertrophy, and an interventricular membranous septal defect, with a modest shunt (Figure 3). A trans-tricuspid gradient of more than 90 mm Hg was measured, leading the care team to hypothesize that the patient could have uncorrected congenital heart disease (CHD) complicated by pulmonary hypertension (Eisenmenger syndrome) (Figure 4). However, physical examination and chest radiograph at admission did not support this hypothesis, because no splitting of the second heart sound or adjunctive diastolic heart sound could be heard and no prominence of the left second arch could be observed, as shown in Figure 5. To better define the diagnosis and to eventually start a treatment with sildenafil or prostanoids, right heart catheterization was then performed. The examination documented normal values of pulmonary arterial pressure (20/8 mm Hg, mean 14 mm Hg) and wedge pressure (16 mm Hg), but elevated right ventricular (RV) pressures (116/6 mm Hg, mean 51 mm Hg) with no unexpected oxygen fall at the oximetric run (O₂ saturation 82% in the pulmonary artery, 76% in the RV, and 69% in the right atrium). Cardiac index by thermodilution estimation was 5 l/min/m².

Figure 3.

Transesophageal Echocardiogram

Ventricular septal defect with a modest passage of sonicated contrast is shown (arrow).

Figure 4.

Elevated Transtricuspid Gradient

Continuous Doppler measurement at transesophageal echocardiogram is shown.

Figure 5.

Chest Radiograph at Admission

A normal distribution of the pulmonary vessels (∗) and no enlargement of the cardiac shape (arrow), hindering the hypothesis of pulmonary hypertension, is represented.

A new echocardiogram finally demonstrated the combination of interventricular septal defect with pulmonary infundibular stenosis and overriding the aorta (Figures 6A to 6C). Focused revision of the images of the first CT scan with contrast medium confirmed the presence of a subpulmonary muscular sleeve (Figure 4D).

Figure 6.

Diagnostic Findings Consistent With Diagnosis of Tetralogy of Fallot

Transthoracic echocardiogram showing the left-right shunt at continuous Doppler (A), the color Doppler flow through the septal defect (B, dashed arrow), the pulmonary outflow gradient at continuous Doppler (C), and the presence of a subpulmonary muscular sleeve at CT scan (D, arrow).

Despite the fact that no arrhythmic event was documented, the hypotension induced by sedatives and the impact of mechanical ventilation on the endothoracic pressures favored the inversion of the shunt. Thus, this required an attempt to elevate systemic blood pressure with norepinephrine in order to warrant oxygen saturation and rendered it impossible to wean the patient off inotropic support or mechanical ventilation.

Management

Tracheostomy was performed, and the patient was then transferred to the intensive care unit at a larger center, where she underwent surgical correction of TOF by infundibular resection and closure of the septal defect with a Dacron patch. The patient was rapidly hemodynamically stabilized with no more need of pharmacological support. The patient was subsequently discharged to a cardiac rehabilitation center after the humerus fracture was surgically corrected with external fixation nails.

Post-pericardiectomy pericardial effusion developed in subsequent weeks (Figure 7), that resolved with corticosteroids.

Figure 7.

Pericardial Effusion

Chest X-ray showing the enlargement of pericardial shadow (arrow).

Follow-Up

At the 6-month follow-up, the patient remained well compensated and underwent successful elective intervention for the removal of her forearm fixation device.

Discussion

We have described a rare case of an adult woman with clinically silent TOF that was unmasked by major noncardiac surgery for a polytrauma and requiring urgent correction due to hemodynamic decompensation.

TOF is the most common form of cyanotic CHD worldwide (35 per 100,000 patients alive at birth [1,2]). This form of CHD is most frequently associated with patients reaching adulthood before the occurrence of symptoms.

Despite the fact that life expectancy without surgery is usually short, rare silent cases in which TOF is detected in adults by chance have been previously described in the literature (3, 4, 5).

In fact, the presentation of the disease is quite heterogeneous, with severity of the cyanosis being related to the degree of the right-to-left shunting. The amount of blood shunted from right-to-left heart is dynamic, depending on the relative resistance in the systemic and pulmonary vasculatures. In some individuals, the pulmonary artery obstruction is fixed, most commonly involving the pulmonary valve, so the degree of shunt predominantly depends on the systemic vascular resistance (SVR). In other cases, the muscular outflow obstruction is more dynamic and delays the presentation of dyspnea only when RV failure has already occurred. Nevertheless, mortality of untreated TOF is very high, with patients having only a 3% chance of surviving until the age of 40 years (6).

Even in the absence of clear symptoms, conditions affecting the hemodynamic balance can lead to an acute heart decompensation and extremely impaired prognosis.

In particular, general anesthesia for noncardiac surgery might unveil an uncorrected CHD and lead to severe complications, if not correctly managed (7). In effect, such procedures can modify the shunt through the septal defect by inducing peripheral vasodilatation and hypotension and by increasing endothoracic pressure with mechanical ventilation. In our case, the acute decompensation could have been ascribed to a vasospasm of the subpulmonary cuff or an imbalance between the systemic and pulmonary pressures, induced by hemorrhage, anesthesia, and pulmonary trauma. In fact, the reduction of systemic blood pressure and vascular resistances, as well as the obstacle to blood flow induced by positive pressure ventilation, could have increased the magnitude of the intracardiac shunt that was unexpected at the moment of the intervention. Indeed, despite the suspicion of TOF, which could have already been raised from the first CT scan, the patient’s urgent condition that required the care team to focus on other issues did not allow for the early identification of the pulmonary outflow obstruction.

In fact, attentive preoperative evaluation of these patients is generally required for their safe surgical management; however, this can be impossible in an emergency procedure, as it was in this case. In effect, it is well described that patients with unrepaired cyanotic CHD often self-limit their activities and underreport their symptoms that are identifiable only through an objective assessment of the functional status via stress test.

Moreover, previous reports (4) have documented the safe peri-interventional management of adult patients with clinically inapparent TOF, by an anesthetic strategy aimed at the maintenance of SVR and the reduction of pulmonary vascular resistance, including induction with ketamine or etomidate and the use of beta-blockers in order to lower the degree of pulmonary obstruction (8).

In fact, Faraoni et al. (5) clearly demonstrated in a large-scale registry that preoperative markers of critical illness (emergency procedure, inotropic support, mechanical ventilation, preoperative cardiopulmonary resuscitation, and acute or chronic kidney injury), the type of lesion (i.e., single-ventricle physiology), and the functional severity of the heart disease were strong predictors of in-hospital mortality in children undergoing noncardiac surgery, criteria that can probably apply also to adults with uncorrected CHD. In the latter, however, the prolonged RV overload can lead to unfavorable RV remodeling and dysfunction, being associated with an increased occurrence of symptoms, arrythmias, and poor prognosis (9,10).

Cardiac magnetic resonance imaging has become increasingly used as routine screening to evaluate RV function, dilation, scar, and interstitial fibrosis in adult patients with TOF (11,12). In this case, the presence of bone nails and hemodynamic instability prevented this kind of evaluation.

Regarding the correction of TOF, although early repair is well established in children (13), the indication for adults is still debated. Indeed, the onset of symptoms or signs of heart decompensation can certainly point in favor of a correction of the CHD, although requiring the attentive balance of operative risk, especially in the case of RV failure that could severely increase the perioperative risk without offering significant benefits on the prognosis or functional status. In effect, previous studies have shown that the main negative predictors of survival after surgical correction in adult TOF cases were polycythemia (14), RV dilatation (15), increasing age (16), and increased RV/left ventricular systolic pressures (16).

Conclusions

Adult patients with TOF represent a challenging subset of patients due to the modest experience of most clinicians and the heterogeneity of the disease, which make understanding the patients’ individual pathophysiology essential to customize the best therapeutic approach. In this case, we demonstrated that management by a multidisciplinary team, including anesthetists, surgeons, cardiologists, and cardiac surgeons, allowed us to safely discharge the patient with no residual disability.

Author Disclosures

The authors have reported that they have no relationships relevant to the contents of this paper to disclose.