Discussion

Normally, aortic valve is tricuspid, separating left ventricle from the ascending aorta. However, in some people, aortic valve can be unicuspid, bicuspid, or rarely even quadricuspid. ^{Reference Oladiran, Nwosu, Dhital and Ezioma1} Quadricuspid aortic valve is a remarkably rare congenital cardiac abnormality with definitive embryological explanation. ^{Reference Sharif, Azzam and Sharif-Rasslan2–Reference Seol, Kim, Cho, Kim, Kim and Kim7} The estimated incidence of quadricuspid aortic valve is variable ranging from 0.008% to 1.46%, depending upon the studied population and imaging modalities used. ^{Reference Oladiran, Nwosu, Dhital and Ezioma1,Reference Veronese, Brandão, Steffen, Pomerantzeff and Jatene8,Reference Hayakawa, Asai, Kinoshita and Suzuki9} Hayakawa et al from Japan reported an incidence of 0.48% among 627 patients undergoing aortic valve surgery; all cases had significant aortic regurgitation and required surgical aortic valve replacement. ^{Reference Hayakawa, Asai, Kinoshita and Suzuki9}

Quadricuspid aortic valve is described by the presence of four aortic valve leaflets, which can be either equal in size or variable in regard to each other. ^{Reference Oladiran, Nwosu, Dhital and Ezioma1} Though, there is no definite gender preference, it is more commonly reported in female patients. ^{Reference Sharif, Azzam and Sharif-Rasslan2} The clinical presentation depends upon functional status of the quadricuspid aortic valve, left ventricular systolic and diastolic function, and associated cardiac or coronary anomalies. ^{Reference Yuan10} Prior to the widespread use of echocardiogram, most cases were diagnosed during cardiac surgery or at autopsy. ^{Reference Hayakawa, Asai, Kinoshita and Suzuki9} Presently, with the use of two-dimensional/three-dimensional echocardiogram, cardiac CT, and cardiac MRI, quadricuspid aortic valve can be reliably diagnosed along with its sequel on heart. ^{Reference Garg, Garg, Agrawal and Sharma11,Reference Suraci, Horvath, Urina, Rosen and Santana12} Quadricuspid aortic valve is straightforwardly visualised on transthoracic echocardiogram with a characteristic X pattern of aortic valve in diastole. ^{Reference Garg, Garg, Agrawal and Sharma11} These patients generally remain asymptomatic without any significant auscultatory finding during childhood; hence, a diagnosis is rarely made in early years. ^{Reference Brock, Tugertimur and Schwartz13} With the passage of time, these patients develop progressive aortic valve regurgitation as a result of fibrosis and incomplete coaptation and about half of them eventually require either aortic valve replacement or repair. ^{Reference Lin, Yin and Wang5,Reference Seol, Kim, Cho, Kim, Kim and Kim7,Reference Hayakawa, Asai, Kinoshita and Suzuki9,Reference Garg, Garg, Agrawal and Sharma11,Reference Brock, Tugertimur and Schwartz13–Reference Pasanisi, Mazzanti and Sassone15} Aortic valve stenosis and aortic root dilatation are less common in comparison to patients with bicuspid aortic valve. ^{Reference Sharif, Azzam and Sharif-Rasslan2,Reference Savino, Quintavalle and Ambrosio6} Quadricuspid aortic valves were classified into seven types by Hurwitz and Roberts (Fig 7). ^{Reference Brock, Tugertimur and Schwartz13,Reference Hurwitz and Roberts16} Of these, types A, B, and C account for more than 85% of the cases. ^{Reference L'Angiocola, Vetrano and Lardieri4} Nakamura et al designed a more simplified classification by focusing on the position of the supernumerary cusp (Fig 8). ^{Reference Oladiran, Nwosu, Dhital and Ezioma1,Reference Nakamura, Taniguchi, Saiki, Morimoto and Yamaga17}

Figure 7.

Seven anatomic variations of QAV, as presented by Brock M et al. ^{Reference Brock, Tugertimur and Schwartz13}

Figure 8.

Nakamura et al classification of QAV as presented by Oladiran O et al. ^{Reference Oladiran, Nwosu, Dhital and Ezioma1}

The association of quadricuspid aortic valve with patent ductus arteriosus was first reported in 1923 by Simonds as a postmortem finding. ^{Reference Simonds18} Other associated anomalies are rare and includes coronary artery anomalies, ^{Reference Hayakawa, Asai, Kinoshita and Suzuki9} non-obstructive cardiomyopathy, fibromuscular sub-aortic stenosis, ^{Reference Seol, Kim, Cho, Kim, Kim and Kim7} rupture sinus of Valsalva, ^{Reference Nakano, Waseda, Ando, Tanabe, Niwa and Amano19–Reference Akerem Khan, Tamin, Burkhart, Araoz and Young21} atrial septal defect, ^{Reference Garg, Garg, Agrawal and Sharma11,Reference Saito, Yoshimura, Miyatsu and Ikeda22} partial anomalous pulmonary venous connection, ^{Reference Doğan, Arısoy, Memiç and Dağlı23} ventricular septal defect, ^{Reference Tatari, Dehaki, Omrani, Ghaheri, Al-Dairy and Mortezaeian24} transposition of great arteries, ^{Reference Erdmenger, Vázquez-Antona and Becerra25} tetralogy of Fallot, ^{Reference Stanescu and Branidou26,Reference Maheshwari, Tanwar and Mittal27} pulmonary valve stenosis, and congenital complete heart block. Infective endocarditis is also a potential complication ^{Reference Seol, Kim, Cho, Kim, Kim and Kim7,Reference Garg, Garg, Agrawal and Sharma11,Reference Jackson, Sarwar, Hwang, Joglekar and Alsafwah28} with reported incidence of 1.4%. ^{Reference Savino, Quintavalle and Ambrosio6}

We are reporting a case of young girl with a quadricuspid aortic valve with mild aortic valve regurgitation, large patent ductus arteriosus, and volume-loaded left heart who had a successful device closure of her patent ductus arteriosus. To the best of our knowledge, such a case is being reported from Pakistan for the first time.

We successfully managed a young girl and quadricuspid aortic valve with mild aortic regurgitation and a large patent ductus arteriosus with volume-loaded LA and LV. It is a rare association as incidence of quadricuspid aortic valve itself varies from 0.008% to 0.043% depending upon the study population and diagnostic modality. ^{Reference Savino, Quintavalle and Ambrosio6} More frequently, quadricuspid aortic valve is an isolated finding but may be associated with other heart lesions. ^{Reference Savino, Quintavalle and Ambrosio6} Tsang et al reported their experience of 50 patients with mean age of 43.5 years at the time of diagnosis along with 32% associated findings including abnormalities of other cardiac valves, septal defects, persistent left superior caval vein, and patent ductus arteriosus. ^{Reference Tsang, Abudiab and Ammash29} Patients with quadricuspid aortic valve should also be carefully evaluated for functional status of aortic valve, cardiac function, and other congenital abnormalities. ^{Reference Seol, Kim, Cho, Kim, Kim and Kim7}

Our case was of a young girl, who presented to us for the first time with complaints of worsening dyspnoea on exertion and fatigability. It is unfortunate to see grown-up patients with easily amenable congenital cardiac defects in developing countries due to lack of health education and infrastructure. The quadricuspid aortic valve was an incidental finding, her major issue was a large unrestricted patent ductus arteriosus with moderate pulmonary hypertension. Her patent ductus arteriosus was measured about 14–15 mm at its narrowest diameter on transthoracic echocardiogram (Fig 5). She underwent successful device closure of her patent ductus arteriosus as her haemodynamics was found to be favourable on cardiac catheterisation study (details are in the case report section). Her case again confirmed our observation and belief that large patent ductus arteriosus behaves unpredictably in different patients especially in regard to the development of severe or irreversible pulmonary hypertension. Our patient had type A quadricuspid aortic valve and had only mild aortic valve regurgitation. As aortic regurgitation is progressive in these patients, thereupon a close follow-up was recommended.

In contrast to bicuspid aortic valve, quadricuspid aortic valve progressively becomes regurgitant. The cases of aortic valve stenosis or ascending aorta dilatation are less common in this cohort. ^{Reference Savino, Quintavalle and Ambrosio6} In a study by Cho et al, 26 patients with quadricuspid aortic valve were identified from 1994 to 2012. Aortic regurgitation was present in 20 of these patients (77%), and the most frequent valve morphology type was three equally sized cusps and one smaller cusp (n = 12; 46%), followed by two larger equally sized cusps and two smaller equally sized cusps (n = 6; 23%). ^{Reference Cho, Son and Park30} The severity of aortic regurgitation appeared to be correlated with patient’s age and valve morphology.

In patients with a satisfactory echo window, transthoracic echocardiography can offer comprehensive diagnosis of quadricuspid aortic valve and associated anomalies. If transthoracic echo window is suboptimal, use of other diagnostic modalities including three-dimensional echocardiography, trans-esophageal echocardiography, CT, and MRI may be warranted. ^{Reference Garg, Garg, Agrawal and Sharma11} We used only transthoracic echocardiogram to diagnose the index case. Echocardiography was also helpful in selecting the size of patent ductus arteriosus occluder as repeated aortogram failed to ideally visualise the patent ductus arteriosus in spite of high volumes of contrast (Fig 6).

In patients with quadricuspid aortic valve with significant aortic valve regurgitation, surgical aortic valve replacement, or repair may be indicated depending upon symptoms, echocardiography findings and relevant centre’s experience and preferences. ^{Reference L'Angiocola, Vetrano and Lardieri4,Reference Lin, Yin and Wang5,Reference Pasanisi, Mazzanti and Sassone15,Reference Hasegawa, Tanaka and Okita31,Reference Kawashima, Komiya, Tsuneyoshi, Shimamoto, Sakai and Hiraoka32} More recently, there have been case reports of safe use of trans-catheter aortic valve implantation in selected patient. ^{Reference Aoyama, Futami, Tanaka, Takeda, Nishimura and Tobaru33,Reference Benkemoun, Bramlage and Beaufigeau34} As patients with quadricuspid aortic valve have tendency to progressively develop aortic regurgitation, careful and regular follow-up in these patients is recommended.