Echocardiography in Simple Congenital Heart Diseases: Guiding Adult Patient Management

Abstract

This article provides comprehensive insights into the evaluation of simple congenital heart diseases (CHDs) in adults, emphasizing the pivotal role of echocardiography. By focusing on conditions such as congenital aortic stenosis, aortic coarctation, patent ductus arteriosus, atrial septal defects (ASDs), and ventricular septal defects (VSDs), the review underscores echocardiography’s intricate contributions to precise clinical decision-making. Echocardiography serves as the primary imaging modality, offering high-resolution visualization of anatomical anomalies and quantification of hemodynamic parameters. It enables tailored therapeutic strategies through its capacity to discern the dimensions, spatial orientation, and dynamic shunt dynamics of defects such as ASDs and VSDs. Moreover, echocardiography’s advanced techniques, such as tissue Doppler imaging and speckle tracking, provide detailed insights into atrial mechanics, diastolic function, and ventricular filling kinetics. Integration of echocardiographic findings into clinical practice empowers clinicians to create personalized interventions based on quantified ventricular function, which spans systolic and diastolic aspects. This approach facilitates risk stratification and therapeutic planning, particularly pertinent in heart failure management within the CHD patient population. In summary, echocardiography transcends its role as an imaging tool, emerging as a precision-guided instrument adept at navigating the complexities of simple CHD in adults. Its ability to expedite diagnosis, quantify hemodynamic impacts, and unravel multifaceted functional dynamics culminates in a comprehensive depiction of these conditions. The fusion of these insights with clinical expertise empowers clinicians to navigate the intricate pathways of CHD, crafting tailored therapeutic strategies characterized by precision and efficacy.

INTRODUCTION

Congenital heart diseases (CHDs) span a spectrum of anomalies, originating during fetal development and persisting into adulthood.[1] While traditionally confined to pediatric cardiology, simple CHD is increasingly assuming a central role in adult cardiology practice.[2] This paradigm shift underscores the recognition that these conditions require lifelong management. The prevalence of adults living with simple CHD has surged due to advancements in medical and surgical interventions during childhood. Contemporary epidemiological studies reveal that around 1% of adults grapple with CHD, and this figure is poised to escalate.[3] The imperative to address these conditions in adulthood is rooted in their potential to inflict substantial morbidity and mortality in the absence of appropriate oversight.[1] Although characterized as “simple,” conditions congenital aortic stenosis (CAS), atrial septal defects (ASDs), ventricular septal defects (VSDs), patent ductus arteriosus (PDA), and aortic coarctation (AC) demand unwavering attention due to their potential to precipitate complications heart failure, arrhythmias, and infective endocarditis.[1]

Echocardiography, often referred to as the “heart’s window,” emerges as an indispensable tool in the diagnostic armamentarium, offering a dynamic and noninvasive perspective into the intricacies of CHD.[4] This imaging modality employs ultrasound waves to visualize cardiac structures, allowing clinicians to explore the dimensions, flow patterns, and mechanical dynamics of the heart. The role of echocardiography extends beyond static anatomical depiction; it serves as an instrumental guide for clinicians, aiding in the comprehensive assessment and management of simple CHD in adults.[5] From the moment, a defect is visualized to the meticulous analysis of shunt dynamics, echocardiography offers a detailed roadmap of hemodynamics and cardiac mechanics.

The integration of techniques such as tissue Doppler imaging provides insights into atrial mechanics and diastolic function, offering a nuanced understanding of ventricular filling dynamics and diastolic interactions.[5] These insights ripple across the management spectrum, impacting therapeutic decisions, risk stratification, and prognostication.

The integration of echocardiographic findings with clinical decision-making forms the cornerstone of optimal patient care.[5] By understanding anatomical and functional insights, clinicians craft tailored interventions, accounting for the complexities of each patient’s condition. Echocardiography’s role in risk stratification and therapeutic planning enhances the precision of medical interventions, fostering improved patient outcomes and enhanced quality of life.

In conclusion, this review aims to underscore how echocardiography serves as a guide for the care of adults with simple CHD. Integrating these insights into clinical practice empowers clinicians to navigate the complexities of CHD, forging a path toward tailored, and effective therapeutic strategies.

CONGENITAL AORTIC STENOSIS

CAS assumes considerable clinical significance due to its diverse manifestations and potential for adverse outcomes. This condition arises from a variety of structural abnormalities affecting the aortic valve, encompassing quadricuspid, bicuspid, and unicuspid morphologies[6] [Figures 1 and 2]. The clinical spectrum spans silent, asymptomatic cases incidentally detected to those presenting with exertional dyspnea, chest pain, and syncope. Notably, the severity of stenosis and compensatory mechanisms of the heart dictate the clinical phenotype.[7] Insights from investigations[6,8] underscore the intricate interplay between aortic valve morphology, hemodynamics, and clinical presentations, crucial for prognostic assessment and therapeutic decisions.

Figure 1.

Unicuspid aortic valve (AV). (a) M mode transthoracic echocardiography (TTE) on aortic valve: eccentric valve closure in diastole. (b) Two-dimensional (2D) TTE short axis aortic level: unicuspid AV during systole. (c and d) 2D transesophageal echocardiography (TEE), long axis view: Systolic doming of aortic valve with dilatation of ascending aorta. (e) 2D TEE: Short axis aortic valve, unicuspid AV during systole. (f) Three-dimensional TEE short axis aortic valve, unicuspid AV during systole. TTE = Transthoracic echocardiography, LV = Left ventricular, RV = Right ventricular, LA = Left atrium, RA = Right atrium, AV = Aortic valve, AA = Ascending aorta

Figure 2.

Unicuspid aortic valve multimodality imaging. (a) Cardiac computed tomography, closure line during diastole of the unicuspid valve. (b) Three-dimensional cardiac magnetic resonance imaging (MRI), dilatation of the ascending aorta. (c) Cardiac MRI, unicuspid aortic valve in systole. (d) Cardiac MRI, unicuspid AV in diastole (closed). AV = Aortic valve, CT = Computed tomography, MRI = Magnetic resonance imaging

Echocardiography is the first-line examination for diagnosing and characterizing CAS, offering detailed insights into valve anatomy, blood flow dynamics, and pressure gradients. Doppler echocardiography, in particular, assumes a pivotal role in quantifying stenosis severity. Key parameters to assess CAS severity are shown in Table 1.[9] Precise estimation of these parameters facilitates risk stratification and optimal intervention timing. Echocardiographic standardization, as underscored in pertinent studies,[7,8,9] is particularly critical for bicuspid aortic valves (BAVs), further augmenting their prognostic implications.

Table 1.

Cutoff values in determining the severity of aortic stenosis

Parameter	Cut-off for severity	Notes
AVA	<1.0 cm2	Indicates severe stenosis and potential need for intervention
Peak aortic jet velocity	>4.0 m/s	High velocities signify significant stenosis, warranting further evaluation
Mean pressure gradient	>40 mmHg	High gradients indicate severe stenosis, often necessitating intervention
DI	<0.25	A value below the threshold signifies severe stenosis and guides clinical decision-making
VR	>0.25	Elevated VR indicates severe stenosis and guides the need for intervention

AVA=Aortic valve area, DI=Dimensionless index, VR=Velocity ratio

Echocardiography’s utility extends beyond diagnosis, profoundly influencing treatment strategies for CAS. Surgical intervention, transcatheter approaches, and medical management are intricately informed by the severity of stenosis, concurrent valvular anomalies, and the patient’s clinical profile.[8] Furthermore, ongoing echocardiographic surveillance empowers timely intervention and optimization of long-term outcomes through disease progression monitoring.[9]

Echocardiography’s pivotal role extends to specific congenital heart conditions, notably BAV anomalies, which demand a refined approach. The intricate interplay between BAV morphology, hemodynamics, and eligibility for sports competition has garnered attention.[10] Echocardiography, not only guides diagnosis but also assessment of BAV’s impact on sports participation. Studies, such as that by D’Ascenzi, examine the echocardiographic evaluation of BAV’s relevance to sports eligibility, aiding in informed decision-making.[10]

In a broader context, echocardiography’s influence is palpable even in the decision-making of surgical interventions. The Ross procedure, a complex surgical technique for aortic valve replacement, holds long-term implications hinging on careful patient selection.[11] Echocardiography’s instrumental role in patient assessment contributes to refining candidacy criteria for such procedures, ensuring favorable long-term results.

Echocardiography’s depth of insight is further manifested in dissecting BAV phenotypes and their associations with diverse patterns of valvular dysfunction.[12] Studies, including Mai et al. meta-analysis, illuminate the complex interrelationships within BAV pathophysiology, valvular function, and clinical implications.[12] Through an extensive search of multiple databases, the study analyzed data from thirteen relevant studies, encompassing BAV with right and left cusps fusion (RL) versus BAV with right and noncoronary cusp fusion (RN) and raphe versus nonraphe subgroups. Notably, BAV-RL patients exhibited a higher incidence of aortic regurgitation, whereas BAV-RN patients displayed a lower incidence of aortic stenosis. Furthermore, the presence of a raphe in BAV patients correlated with an elevated risk of aortic regurgitation without affecting the incidence of aortic stenosis. Gender and mean age were found to have no impact on these observed associations. These findings underscore the relationship between distinct BAV phenotypes and aortic valve dysfunction, revealing BAV-RL and BAV with raphe as prone to aortic regurgitation, while BAV-RN patients are more predisposed to aortic stenosis.[13]

AORTIC COARCTATION

AC, involves the narrowing of the aorta.[14] This narrowing typically occurs just beyond the left subclavian artery, causing a constriction that alters blood flow dynamics and leads to significant clinical implications [Figure 3]. Understanding the pathophysiology of AC is essential for comprehending the clinical features and potential complications associated with this condition.

Figure 3.

Coarctation of aorta. (a) Two-dimensional (2D) transthoracic echocardiography (TTE), suprasternal view, coarctation of aorta. (b) 2D TTE Doppler, suprasternal view, high gradient by CW Doppler. (c) Cardiac computed tomography (CT), coarctation of aorta. (d) Three-dimensional (3D) cardiac CT, pre-subclavian coarctation of aorta. (e) Cardiac magnetic resonance imaging (MRI), post subclavian coarctation of aorta. (f) 3D cardiac MRI, coarctation of aort. CW = Continuous wave, CT = Computed tomography, MRI = Magnetic resonance imaging

The pathophysiology of AC primarily revolves around the physical narrowing of the aorta. This constriction results in increased pressure proximal to the narrowing, leading to greater resistance to blood flow and increased workload on the left ventricle (LV).[14] Consequently, the LV compensates by hypertrophying to generate the necessary force to overcome the constriction. Despite the narrowing, blood continues to flow distally but at a reduced pressure due to the resistance created by the constriction. Clinical evaluation of AC involves assessing several parameters, each with its defined cutoff values [Table 2].[14] A peak-to-peak gradient across the coarctation site >20 mmHg indicates the presence of a significant obstruction, warranting further investigation. Similarly, an Arm-Leg Blood Pressure Gradient exceeding 20 mmHg suggests a potential coarctation and prompts additional evaluation. The ratio of post-coarctation to pre-coarctation blood pressure, below 0.67, signifies severe coarctation, necessitating intervention. The presence of visible collateral circulation serves as a marker for significant coarctation. These clinical thresholds collectively aid in determining the severity of AC and play a crucial role in guiding appropriate treatment strategies.[14]

Table 2.

Cutoff values in determining the severity of aortic coarctation

Echocardiographic parameter	Cutoff value	Significance
Peak velocity across coarctation site	>2.5 m/s	High velocity suggests significant coarctation, prompting further evaluation
Peak gradient across coarctation site	>20 mmHg	Elevated gradient indicates the presence of significant coarctation, requiring attention
Velocity ratio between precoarctation and	<0.75	A low ratio signifies severe coarctation, indicating potential intervention
Postcoarctation aorta
CoA-I	<0.5	A value below the threshold indicates severe coarctation and guides management decisions
Coarctation length	<20 mm	Short length suggests significant coarctation requiring evaluation and potential treatment
Diastolic drag	Presence	The presence of diastolic drag suggests a more severe coarctation and influences treatment

CoA-I=Coarctation index

Echocardiography allows clinicians to visualize the site and extent of AC with high precision. Doppler imaging also provides valuable insights into the presence and direction of collateral vessels that develop to bypass the obstruction. These collateral vessels play a compensatory role in maintaining blood flow to the lower extremities and are often visualized through color Doppler imaging. Detecting collateral circulation is crucial for understanding the overall hemodynamic status of the patient and guiding appropriate management strategies.[14,15,16,17]

Despite successful surgical correction of AC, some residual effects on cardiac mechanics and myocardial deformation may persist. Research has shown that patients, even after repair, may exhibit abnormal regional myocardial deformation properties and increased aortic stiffness, which can influence overall cardiac function.[16,17] LV geometry and function may not return to complete normalcy, especially when compounded by factors such as obesity. Indeed, studies have indicated that obesity can further impact LV geometry and function in pediatric patients after coarctation repair.[18]

Hypertension is a characteristic clinical feature of AC.[15] The increased resistance caused by the narrowing of the aorta leads to elevated blood pressure in the upper extremities. Notably, this hypertension is often more pronounced in the arms than in the legs, creating a disparity in blood pressure between the upper and lower body. Diminished or even absent pulses in the lower extremities are commonly observed due to the reduced blood flow beyond the constriction. This is often referred to as “brachial-femoral delay,” where pulses in the arms are stronger compared to those in the legs.[15] The complications stemming from untreated AC are numerous and severe. Long-term hypertension due to constriction can lead to LV hypertrophy. This hypertrophy, while initially compensatory, can eventually result in impaired cardiac function and congestive HF. Moreover, the increased pressure can lead to the formation of aneurysms or weakened areas of the aortic wall, which may eventually rupture.[18]

Intriguingly, recent research has aimed to optimize treatment strategies for AC. Studies have compared the efficacy of different medications, such as atenolol and enalapril, in managing hypertension after successful repair. These investigations contribute to the ongoing effort to refine postsurgical care and improve patient outcomes.[15]

Focusing on normotensive patients who had undergone successful surgical correction for AC, another study[16] found that despite normalized blood pressure levels, AC patients exhibited persistent abnormal regional myocardial deformation properties, indicating ongoing cardiac alterations. The study also highlighted increased aortic stiffness, which can impact overall cardiovascular function. By utilizing strain rate imaging alongside standard echocardiography and ambulatory blood pressure monitoring, the research emphasized the importance of comprehensive imaging techniques in assessing the long-term cardiovascular health of postsurgical AC patients.

PATENT DUCTUS ARTERIOSUS

PDA is a congenital heart defect that affects the circulatory system, causing significant hemodynamic changes and potential complications. The impact of a PDA on circulation is multifaceted. During fetal development, the ductus arteriosus serves to divert blood away from the developing lungs, which are nonfunctional in utero, and into the systemic circulation.[19] However, after birth, the lungs become functional, and the ductus arteriosus is meant to close, allowing for proper oxygenation of the blood. In the case of PDA, the vessel remains open, causing a shunt of blood from the higher-pressure aorta to the lower-pressure pulmonary artery. This results in an increased volume of blood flowing into the lungs, potentially leading to pulmonary congestion and increased strain on the heart’s left atrium and ventricle. Consequently, the heart’s workload increases, and over time, this can lead to complications such as LV hypertrophy, congestive heart failure (HF), and pulmonary hypertension.[20]

The presentation of PDA can vary depending on the age of the patient. In infants, common signs and symptoms include difficulty feeding, poor growth, rapid breathing, and frequent respiratory infections. As the child grows older, other signs may emerge, such as fatigue, difficulty exercising, and a heart murmur, particularly in the left infraclavicular region.[20] However, it is important to note that some individuals with PDA might not exhibit symptoms until later in life, especially if the defect is small. In adults, the clinical presentation can be subtle, with symptoms such as shortness of breath, fatigue, and an increased risk of developing infective endocarditis.[21]

Recent research[21] has focused on understanding the various hemodynamic profiles of PDA in adults. This study explored the different ways in which PDA can affect the cardiovascular system in adult patients. It highlighted the importance of recognizing the diverse presentations of PDA, as they can impact treatment decisions and management strategies. One of the key findings of the study was the identification of different hemodynamic patterns associated with PDA in adults. Unlike the classic presentation observed in infants, where PDA leads to a left-to-right shunt of blood, the study highlighted a range of shunt patterns in adult patients. These patterns included not only the traditional left-to-right shunt but also right-to-left and bidirectional shunts. This variation in shunt patterns results from the complex interactions between systemic and pulmonary pressures in adult patients, ultimately influencing blood flow direction through the PDA. Moreover, the study emphasized the importance of recognizing these diverse hemodynamic profiles, as they have implications for clinical management and treatment decisions. The choice of treatment, whether medical, interventional, or surgical, should be tailored to the specific hemodynamic profile of the PDA. For instance, patients with significant left-to-right shunts might be considered for closure to prevent the long-term effects of volume overload on the heart. On the other hand, patients with bidirectional or right-to-left shunts might require careful evaluation and consideration of potential risks before proceeding with closure.[21]

Other recent research has aimed to uncover the molecular mechanisms underlying the remodeling of the PDA[22] delving into the molecular pathways that contribute to its persistence. Understanding these mechanisms is essential for developing targeted therapies that can promote the closure of the PDA and prevent associated complications.

Echocardiography enables the identification of PDA by visualizing the persistent connection between the descending aorta and the pulmonary artery. Using two-dimensional (2D) imaging, PDA can be observed as a tubular structure that bridges the two major blood vessels. The echocardiographic images also allow clinicians to assess the location and size of the ductus arteriosus, helping to differentiate between different types of PDAs, such as isolated PDAs or those associated with other congenital heart defects.[19,21]

Color flow Doppler is particularly valuable in visualizing the flow of blood through the PDA. First, it allows clinicians to visualize the shunt flow across the PDA. In the presence of a shunt, blood flows from the higher-pressure aorta to the lower-pressure pulmonary artery. This flow can be seen as a color jet on the Doppler image, indicating the direction and velocity of the blood flow. By assessing the direction and intensity of this color jet, clinicians can determine the presence and direction of the shunt.[22]

Second, color flow Doppler provides an estimate of the size of the shunt. The size of the shunt is determined by the amount of blood that flows through the PDA with each heartbeat. Color flow Doppler allows clinicians to measure the width of the color jet representing the shunt flow. The wider the jet, the larger the shunt is likely to be [Table 3]. This information is crucial in determining the severity of PDA and guiding treatment decisions. Small PDAs might not require intervention, while larger ones might necessitate medical therapy or even surgical closure.[19,22]

Table 3.

Comprehensive overview of the echocardiographic parameters used to diagnose and assess the significance of patent ductus arteriosus, as well as their role in discriminating significant shunting

Echocardiographic parameter	Discrimination of significant PDA
Size of the PDA	Larger PDAs are more likely to result in significant shunting
Left atrial and left ventricular enlargement	Enlargement indicates volume overload due to significant shunt
Pulmonary artery flow velocity	Increased flow velocity suggests larger left-to-right shunt
Qp/Qs	Qp/Qs >1.5 indicates significant shunting
Descending aortic flow reversal	Retrograde flow in the descending aorta implies substantial shunt
Pressure half-time of PDA	Shorter pressure half-time signifies a larger shunt

PDA=Patent ductus arteriosus, Qp/Qs=Pulmonary-to-systemic blood flow ratio

ATRIAL SEPTAL DEFECTS

ASD are congenital heart abnormality characterized by a communication at the atrial level. ASDs can be broadly categorized into four main types based on the location of the defect: secundum, primum, sinus venosus, and coronary ASD [Figures 4 and 5]. While they all involve abnormal communication between the atria, their characteristics, potential complications, and management vary.[23]

Figure 4.

(a) Two-dimensional (2D) transthoracic echocardiography (TTE) short axis mitral level with cleft of anterior mitral valve (MV) leaflet. (b) 2D TTE apical four chamber view A, primum type atrial septal defect with left-to-right interatrial shunt. (c) Three-dimensional transesophageal echocardiography (TEE), surgeon’s view of the MV, cleft of anterior MV leaflet. (d) 2D TEE with color, severe mitral regurgitation. (e) 2D four chamber view with color, primum type SD with left-to-right interatrial shunt. TTE = Transthoracic echocardiography, AV = Aortic valve, MV = Mitral valve, ASD = Atrial septal defect, MR = Mitral regurgitation

Figure 5.

(a) Two-dimensional (2D) transthoracic echocardiography apical four chamber view, large secundum type atrial septal defect (ASD). (b) 2D transesophageal echocardiography, four chamber view, large secundum type ASD. (c) Cardiac computed tomography, large secundum ASD. (d) Complete AVSD, large VSD, large primum type ASD. TTE = Transthoracic echocardiography, ASD = Atrial septal defect, CT = Computed tomography, AVSD = Atrioventricular septal defect, VSD = Ventricular septal defect

Secundum ASDs are the most common type and typically involve an opening in the central part of the atrial septum. These defects often result from an incomplete closure of the foramen ovale, a natural hole that exists in the fetal heart for fetal circulation. Secundum ASDs may remain asymptomatic for many years, especially if they are small. However, over time, blood from the left atrium can shunt to the right atrium, potentially leading to right-sided heart enlargement and pulmonary hypertension. Echocardiography plays a crucial role in diagnosing and monitoring secundum ASDs, as it enables the visualization of the defect and assessment of its size and impact on cardiac chambers.[23]

Primum ASDs are less common and are typically located in the lower part of the atrial septum. These defects are often associated with other congenital heart abnormalities, such as cleft mitral valves [Figure 4]. Primum ASDs can lead to a left-to-right shunt, causing increased blood flow to the right atrium and ventricle. Over time, this can lead to volume overload of the right-sided chambers and, in some cases, result in pulmonary hypertension. Diagnosis and assessment of primum ASDs also heavily rely on echocardiography, allowing clinicians to visualize the defect, assess its impact, and evaluate associated anomalies.[24]

Sinus venosus defects occur near the junction of the superior vena cava and the right atrium. These defects can be associated with anomalous drainage of the right pulmonary veins into the right atrium, which further complicates blood flow patterns. Sinus venosus defects can lead to right atrial enlargement, and if not treated, they may result in pulmonary hypertension and right ventricular dysfunction. Echocardiography, including color flow Doppler imaging, is crucial in identifying these defects and assessing the abnormal blood flow patterns associated with them.[25]

An unroofed coronary sinus (UCS) is a rare congenital cardiac anomaly where there is a communication between the coronary sinus and the left atrium, resulting in a direct shunt of blood between these two structures. In cases of a UCS, a portion of the atrial septum that separates the coronary sinus and the left atrium is absent or incomplete.

This leads to a left-to-right shunt and abnormal communication between the venous and systemic circulations.[26] The presence of a UCS can result in the mixing of oxygenated and deoxygenated blood, potentially leading to various clinical manifestations, including cyanosis, exercise intolerance, and risk of paradoxical embolism. Diagnosis of this condition is often made through echocardiography; injecting saline agitate solution in the left antecubital vein.[26]

Complications related to interatrial shunting in ASDs are primarily driven by the volume overload that occurs in the affected chambers. Over time, increased blood flow from the left atrium to the right atrium can lead to right atrial and ventricular dilation. This can result in symptoms such as fatigue, shortness of breath, and palpitations. In addition, long-standing volume overload can lead to the development of atrial arrhythmias, including atrial fibrillation. Pulmonary hypertension is another potential complication, especially in larger defects, as the increased blood flow to the right side of the heart can lead to changes in pulmonary vascular resistance (PVR).[27]

Strain rate imaging was employed to assess atrial function postsurgical and percutaneous ASD closure. Both closure methods exhibited positive effects on atrial function, with improved atrial strain rate parameters indicating enhanced mechanical performance. Similar benefits were observed in patients undergoing percutaneous closure as well.[28,29] Furthermore, spectral Doppler interrogation of pulmonary veins provided insights into hemodynamic changes associated with ASDs. Abnormalities in pulmonary vein flow patterns reflected alterations in left atrial and ventricular pressures due to interatrial shunting.[30]

Strain rate imaging not only assessed atrial function but also demonstrated positive impacts on ventricular function following surgical and percutaneous ASD closure, highlighting the potential of strain rate parameters to signify improved ventricular mechanics post-closure, emphasizing the holistic benefits of these closure procedures.[31]

While not exclusive to ASDs, research underscored the significance of assessing RV function in adults with congenital heart defects.[32] Recent literature highlights the importance of accurate RV measurements in cases of pressure or volume overload, emphasizing the need for a comprehensive echocardiographic approach to the right ventricle (RV) in adult patients with CHD. Despite the challenges posed by the RV’s complex anatomy and diverse morphologies, reliable and repeatable quantification of RV dimensions and function is essential for informed decision-making and optimal intervention timing.[32]

Indications and contraindications for ASD closure revolve around patient selection, incorporating factors such as defect size, shunt magnitude, clinical symptoms, and potential complications [details in Table 4]. While closure proved beneficial for most cases with significant shunting, specific scenarios raised uncertainty about its advantage.[33]

Table 4.

Echocardiographic parameters to assess severity and hemodynamic consequences of atrial septal defects

Echocardiographic parameter	Cutoff value	Significance
Right ventricular enlargement	RV/LV diastolic diameter ratio	Ratio >1 indicates significant right ventricular enlargement due to increased volume overload
Left atrium enlargement	LA/AO ratio	Ratio >1.5 suggests left atrial enlargement as a result of increased left-to-right shunting
Pulmonary artery hypertension	RVSP	RVSP >3.40 m/s indicates a high probability of pulmonary artery hypertension
Shunt flow dynamics	Qp/Qs ratio	Qp/Qs >1.5 signifies left-to-right shunting and increased pulmonary blood flow

RV=Right ventricle, LV=Left ventricle, RVSP=RV systolic pressure, Qp/Qs=Pulmonary-to-systemic blood flow ratio, LA/AO=Left atrium-to-aortic ratio

Efficacy in transcatheter ASD closure was evidenced by an ASD occluder study, reporting successful closure rates and minimal complications. This accentuated the pivotal role of advanced devices in enhancing closure outcomes.[34,35,36]

A paradigm shift in understanding ASD in adulthood was introduced, recognizing its extended natural history. This highlighted the imperative for comprehensive assessment and tailored management strategies to address its evolving nature.[35] Accurate sizing’s significance in transcatheter ASD closure was underscored, particularly guided by echocardiography and imaging techniques to ensure optimal procedural outcomes.[36] A broader perspective on ASD closure emerged in a commentary, acknowledging transcatheter advancements while emphasizing ongoing research to refine patient selection criteria and improve outcomes.[37] In addition, transcatheter closure benefits were discussed in a study, highlighting the technique’s minimally invasive advantages. Proper patient selection and comprehensive assessment were emphasized for favorable outcomes.[38] In a different context, a recent study explored the diagnostic potential of contrast transesophageal three-dimensional echocardiographic imaging for patent foramen ovale assessment, aiming to illuminate its clinical utility.[39]

VENTRICULAR SEPTAL DEFECTS

VSDs are common CHD characterized by openings in the septum that separates the heart’s two ventricles. There are several types of VSDs, each distinguished by their location within the ventricular septum. These types include membranous, muscular, perimembranous, and doubly committed subarterial defects[40] [Figure 5].

Muscular VSDs are situated in the muscular portion of the septum and can occur anywhere in the ventricles. Perimembranous VSDs are adjacent to the membranous septum and are often positioned near the tricuspid and aortic valves. Doubly committed subarterial VSDs are found beneath both the aortic and pulmonary valves. The type and location of the VSD influence the flow of blood between the ventricles and the potential clinical implications.[41] Muscular VSDs, distributed across the muscular region, can develop anywhere within the ventricles. Perimembranous VSDs, closely situated near the tricuspid and aortic valves, pose a specific challenge due to their proximity to these critical structures. Finally, doubly committed subarterial VSDs, located beneath both the pulmonary and aortic valves, possess distinctive characteristics due to their unique positioning.[41]

The hemodynamic repercussions of left-to-right shunting in VSDs arise from the flow of oxygenated blood from the LV to the RV, driven by the pressure gradient between these two chambers. It is crucial to highlight that this escalated volume overload in the right heart circumvents the RV and directly enters the pulmonary circulation.[41] Over time, the heightened blood flow coursing through the pulmonary arteries can induce pulmonary hypertension and lead to right ventricular hypertrophy. Moreover, the LV may undergo dilation and eccentric hypertrophy due to the augmented preload, potentially culminating in heart failure. The extent of these hemodynamic effects hinges on factors such as the size and location of the VSD, the prevailing pressures in the ventricles and pulmonary arteries, and their interplay.[42]

In particular, the hemodynamic consequences of VSDs, particularly the left-to-right shunting of blood, significantly impact the heart’s function and structure. A left-to-right shunt signifies that oxygenated blood from the LV is allowed to flow back into the RV during systole, generating a volume overload in the right heart chambers. This phenomenon triggers the RV to accommodate a larger blood volume than usual, leading to increased workload and subsequent hypertrophy. Simultaneously, the LV becomes subject to volume overload during diastole. The increased blood volume returning from the RV through the VSD results in LV dilation and eccentric hypertrophy. While these adaptations initially aim to maintain cardiac output and circulation, prolonged volume and pressure overload can eventually precipitate complications such as pulmonary hypertension, RV failure, and arrhythmias.

Echocardiography emerges as an indispensable diagnostic modality in the comprehensive assessment of VSDs, allowing clinicians to visualize the anatomic location and type of VSD, providing a foundational understanding of the defect’s characteristics. Furthermore, the dimensions of the VSD can be estimated on 2D imaging, enabling a preliminary assessment of the defect’s size and potential clinical implications.[43]

The real power of echocardiography, however, becomes evident when employing color Doppler imaging. In left-to-right shunts, color Doppler reveals blood flowing from the LV to the RV. Importantly, the size and intensity of the Doppler jet provide valuable insights into the volume of shunt flow, which is crucial in gauging the severity of the defect.[44] In addition, CW Doppler assists in calculating pressure gradients across the VSD. This information furnishes a more profound understanding of the hemodynamic relevance of the shunt and the degree of left-to-right flow. Moreover, color Doppler aids in assessing the function of adjacent valves, including the tricuspid and aortic valves, offering insight into their responses to the altered flow patterns engendered by the VSD.

Echocardiography can provide insights into the feasibility of both percutaneous and surgical treatment options.[44] Both transcatheter and surgical closure of VSDs have specific indications and contraindications. Transcatheter closure is indicated for cases with various criteria, such as cardiomegaly, elevated Qp/Qs ratio, and specific postoperative or post-infarct VSDs. However, it is contraindicated in situations of high PVR, irreversible pulmonary hypertension, active infection, inadequate rim below the aortic valve, aortic valve prolapse, and other conditions. Surgical closure, on the other hand, is indicated for large, hemodynamically significant, or complex defects, as well as those not amenable to transcatheter closure. It is contraindicated in patients who are hemodynamically unstable, have inadequate access to surgical repair, severe pulmonary hypertension, significant aortic valve regurgitation, and other conditions [Table 5]. The decision for closure should be tailored to individual patient factors and anatomical considerations.[44]

Table 5.

Comparison of the indications and contraindications for both transcatheter and surgical closure of ventricular septal defects

Transcatheter closure indications	Transcatheter closure contraindications	Surgical closure indications	Surgical closure contraindications
Cardiomegaly or left ventricular enlargement	High PVR	Large defects or those with complex anatomy	Hemodynamically unstable patients
Qp/Qs >1.5	Irreversible pulmonary hypertension	Hemodynamically significant defects	Inadequate access for surgical repair
Failure to thrive	Active infection	Complex VSDs with associated anomalies	Severe pulmonary hypertension
Recurrent respiratory infections requiring hospitalization	Inadequate rim below the aortic valve	Patients not amenable to transcatheter closure	Significant aortic valve regurgitation
History of infective endocarditis	Aortic valve prolapse	Infection of the defect	Complex or inaccessible anatomy
Postoperative VSDs with significant leak	Presence of significant aortic valve regurgitation	Large aneurysm or multiple defects	Co-existing cardiac anomalies
Postinfarct VSDs due to myocardial rupture	Significant residual shunting postclosure		Intractable arrhythmias
	High PAP
	Inadequate device sizing for defect closure
	Inability to achieve effective device placement
	Unfavorable anatomy for transcatheter approach

PVR=Pulmonary vascular resistance, PAP=Pulmonary artery pressure, Qp/Qs=Pulmonary-to-systemic blood flow ratio, VSDs=Ventricular septal defects

A study conducted by Singhi and Sivakumar[44] introduces an echocardiographic classification system for perimembranous VSDs to guide the selection of occluder designs for their transcatheter device closure. The classification categorizes defects into four groups based on their anatomical features: Group A, without aortic margin; Group B, with thick aortic margin; Group C, with membranous septal aneurysm; and Group D, defects restricted by tricuspid valve attachments. The proposed ideal device designs vary depending on the group, with an asymmetric device recommended for Group A defects, duct occluder I (ADOI) and muscular ventricular septal occluder (MVSO) for Group B, thin profile duct occluder II (ADOII) for Group C, and ADOI for Group D. The study involved 80 patients with VSDs, and the selected device size was 0–2 mm larger than the defect. Results showed that successful closure was achieved in 80 patients with VSDs. Device selection was based on the echocardiographic classification, with specific designs utilized for each group. The study demonstrated the utility of the classification system in guiding device selection for successful closure. In Group A defects, an asymmetric device was used, while different designs, including ADOI, ADOII, and MVSO, were employed for Group B and C defects. Group D defects were closed using ADOI and ADOII devices. Notably, no instances of late aortic regurgitation or heart block were observed in follow-up periods exceeding 7 years. The proposed classification system offers a tailored approach to device selection based on specific anatomical characteristics, resulting in successful transcatheter closures. By leveraging echocardiographic insights, clinicians can optimize outcomes for patients with diverse types of perimembranous VSDs, ensuring effective closure, and long-term clinical stability.[44]

Another study[45] investigated the criteria for the application of asymmetric Amplatzer occluders in the closure of perimembranous VSDs. The retrospective analysis included 18 children with perimembranous VSDs who underwent attempted asymmetric occluder closure. The study assessed various parameters, including defect diameter, occluder size, presence of aneurysm, and aortic valve prolapse. Successful device implantation was achieved in only 5 out of 18 patients. The successful cases demonstrated a significantly smaller VSD size and a lower ratio of aortic valvular prolapse compared to the failed cases. Successful cases also experienced arrhythmia complications, which were managed with drug treatment. The study identified a cutoff value of 5.7 mm for the defect size, beyond which the success of asymmetric amplatzer occluder implantation was limited. The findings suggest that while the application of asymmetric occluders can be effective in cases with superior localized VSDs, it is restricted in cases with aortic valvular prolapse and larger VSD sizes.[45]

ASSESSMENT OF SYSTOLIC AND DIASTOLIC FUNCTION IN CHD (CONGENITAL HEART DISEASE)

The research landscape within CHD has been enriched by a multitude of studies that explore systolic and diastolic cardiac function, with a special focus on the LV and RV systolic function in infants and adults with congenital heart defects. These studies explained various facets of cardiac mechanics, contributing to understanding of the hemodynamic consequences of these anomalies and their impact on ventricular function.[46,47,48,49] One study investigated the influence of increased preload on LV systolic function in infants with CHD.[46] This echocardiographic exploration focused on the LV’s response to elevated preload levels, potentially stemming from altered hemodynamics due to structural cardiac anomalies. The findings provided insights into the adaptability of the LV to varying hemodynamic demands within this susceptible population.

In a separate investigation, researchers utilized color DTI to assess RV systolic function in patients with CHD.[47] This innovative methodology facilitated a comprehensive analysis of RV mechanics and performance in the presence of structural cardiac defects.

Amosova et al.[48] delved into the complexity of systolic and diastolic function of heart ventricles in adult patients with CHD, specifically those in the phase of Eisenmenger’s syndrome. In this study involving 55 patients with CHDs in the Eisenmenger’s syndrome phase, with various heart defects, aged 14–53, the majority experienced heart failure in functional classes I-II or III-IV. Cardiac assessments revealed moderate RV systolic dysfunction, as indicated by dilation and reduced function of the inferior vena cava, while the LV showed an initial stage of systolic dysfunction and diastolic dysfunction in both ventricles characterized by relaxation impairment.

Prevalence and prognostic implications of LV systolic dysfunction in adults with CHD[49] were the object of a retrospective study aiming to assess the prevalence, risk factors, and prognostic significance of LV systolic dysfunction as well as the impact of cardiac therapies such as guideline-directed medical therapy and cardiac resynchronization therapy. Among 4358 patients, 12% had LV systolic dysfunction, which was more prevalent in those with right-sided lesions; LV systolic dysfunction was linked to cardiovascular events, and guideline-directed medical therapy and cardiac resynchronization therapy led to notable improvements in the left ventricular ejection fraction and biomarkers.

While conventional “pump indices” like ejection fraction may be limited due to factors such as loading conditions, newer techniques such as fiber shortening and strain imaging show promise in providing more accurate insights into myocardial contractility and regional functional details in CHD patients, although their clinical impact awaits long-term follow-up studies.[50] Cheung[51] provided a comprehensive assessment of RV function in CHD, emphasizing the potential of novel echocardiographic techniques. These advanced methods, including quantification of RV volumes and assessment of myocardial deformation, hold promise for enhancing the assessment of RV function beyond traditional approaches in adolescent and adult patients with CHD.[51]

The noninvasive assessment of diastolic function in CHD was discussed in a recent study[52] delved into the intricate interplay between atrial and diastolic function, offering insights into how atrial mechanics contribute to the holistic evaluation of cardiac health within this population. The review highlights that atrial function, particularly its reservoir, conduit, and contractile phases, plays a significant role in assessing diastolic dysfunction in CHD, showing a general pattern of dysfunction across various CHD conditions.[52]

Contributing to the discourse on RV diastolic function in CHD, researchers provided a succinct overview of this crucial aspect.[53] Recognizing the pivotal role of diastolic dysfunction in shaping CHD outcomes, their work highlighted the significance of RV diastolic mechanics. This contribution aligns with the ongoing pursuit of comprehending ventricular function, encompassing both its systolic and diastolic dimensions.[53] Exploring the intriguing dichotomy of heart failure in adult CHD, researchers examined scenarios involving both reduced and preserved ejection fractions.[54] Their investigation extended beyond the anatomical considerations of CHD, delving into the different spectrums of heart failure presentations.[54]

Imaging plays a pivotal role in the lifelong care of adults with CHD. Echocardiography remains the primary imaging choice for inpatient, outpatient, and perioperative care, while cardiovascular magnetic resonance (CMR) and computed tomography (CT) provide complementary anatomical and functional information. Advances in echocardiographic techniques, faster CMR imaging, and reduced CT radiation doses have expanded noninvasive imaging options, enabling tailored application of multiple modalities when combined with specialized adults with CHD expertise for this diverse patient population.[55]

Tailoring treatment approaches to match the specific underlying physiology stands as a crucial insight. A recent comprehensive analysis[54] deeply explores HF intricacies among adults with CHD, with a specific focus on HF characterized by reduced ejection fraction (HFrEF) and preserved ejection fraction (HFpEF). A significant discovery of this research involves distinguishing between HFrEF and HFpEF in adult CHD cases. HFrEF often stems from ventricular malfunction due to excessive volume or pressure, whereas HFpEF predominantly arises from impaired diastolic function linked to factors such as heightened ventricular stiffness. This differentiation carries therapeutic implications, given that interventions suitable for one category might not be effective for the other. Established HF treatments such as angiotensin-converting enzyme inhibitors, beta-blockers, and mineralocorticoid receptor antagonists remain pertinent for managing HFrEF in adult CHD cases. Conversely, addressing HFpEF’s intricate nature calls for tailored strategies that target the underlying causes of diastolic dysfunction.

Acknowledging the evolving landscape of HF among adults with CHD due to enhanced surgical and interventional outcomes, leading to extended patient lifespans, becomes imperative. This paradigm shift necessitates vigilant, long-term monitoring and observation to identify the emergence and progression of heart failure.[54] Patients with complex conditions like CHD might advance to end-stage HF, potentially requiring heart transplantation. Insights from the study on heart transplant recipients with maintained atrial function following the bicaval technique underscore the promising outcomes of advanced surgical interventions in managing cardiac irregularities, instilling optimism for enhanced results and quality of life among individuals with CHD who could eventually necessitate cardiac transplantation.[56,57] The demonstrated effectiveness of echocardiography in identifying cardiac dysfunction and guiding management strategies for heart transplant recipients further underscores its significance in overseeing such cases.

CONCLUSION

Establishing dedicated specialized centers is crucial to address the intricate challenges posed by CHD that persist into adulthood. This review underscores the unique demands of managing uncomplicated CHD in adults, with a particular focus on the pivotal role of echocardiography. The evolving medical landscape emphasizes the strategic necessity of these centers for several key reasons.

First, the transition of CHD from childhood to adulthood requires seamless medical care. The dynamic nature of these conditions demands expertise spanning pediatric and adult cardiology. Specialized centers ensure a continuous care approach that considers the lasting consequences of structural anomalies and adjust interventions to cater to evolving adult patient needs.

Second, the substantial impact of CHD on patient outcomes underscores the need for precise diagnosis and management. Echocardiography, as discussed in the review, is an indispensable tool for this purpose. The integration of clinical expertise and technological capabilities in these centers enhances diagnostic accuracy and therapeutic effectiveness.

Moreover, the complexities inherent in uncomplicated CHD necessitate multidisciplinary collaboration. Specialized centers bring together diverse expertise, including adult cardiologists, pediatric subspecialists, cardiac surgeons, and imaging specialists. This collaborative approach facilitates a comprehensive evaluation of patient conditions, informed by insights from various disciplines, leading to well-informed decisions.

The importance of early detection and intervention cannot be overstated. Even seemingly straightforward CHD can harbor latent complications that manifest insidiously. Specialized centers are equipped to conduct vigilant surveillance, detecting subtle changes through advanced echocardiographic assessments. This proactive approach enables timely intervention, arresting the progression of complications and improving long-term outcomes.

In this context, the role of echocardiography emerges as pivotal. Its ability to provide real-time visualization, precise hemodynamic quantification, and functional evaluation aligns seamlessly with the challenges of managing CHD in adulthood. The review’s emphasis on echocardiography resonates within specialized centers, where this imaging technique transforms into a precision instrument, guiding patient-centered care strategies.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.