Pattern recognition for prenatal diagnosis of a parachute mitral valve

Archives of Gynecology and Obstetrics https://doi.org/10.1007/s00404-025-08027-1 EDITORIAL Pattern recognition for prenatal diagnosis of a parachute mitral valve Adeline Walter1 · Ruben Plöger1 · Florian Recker1 · Annegret Geipel1 · Ulrich Gembruch1 · Brigitte Strizek1 Received: 6 March 2025 / Accepted: 1 April 2025 © The Author(s) 2025 Parachute mitral valve (PMV) refers to a heterogeneous spectrum of congenital mitral valve stenosis (MS) that accounts for 0.17% of all congenital heart defects [1]. True PMV is defined as shortened and thickened chordae tendineae inserting into a single papillary muscle with the anterolateral papillary muscle group typically missing (true PMV), while in parachute-like mitral valve (PLMV) most or all chordae converge on a dominant papillary muscle with the other papillary muscle elongated and displaced higher in the ventricle. Both types lead to a reduced mobility of the mitral valve with a decreased effective mitral orifice and in consequence to a functional and anatomical obstruction of the left ventricular inflow [2–4]. PMV/PLMV are commonly diagnosed in association with an underdevelopment of the left ventricular cavity, or other obstructions of the left ventricular outflow tract (LVOT), describing in this constellation the Shone complex [5, 6]. Characterized by multilevel left-sided cardiac obstructions, a complete form including PMV, supravalvar mitral ring, or mitral stenosis (MS) combined with the two different LVOT (sub/supra-aortic stenosis (AS), or bicuspid aortic valve, and coarctation of the aorta (CoA)), can be differentiated from the incomplete form, existing of the described LV inflow obstruction with at least one LVOT [6–8]. If Shone complex is suspected, prenatal counseling should be changed accordingly, as published data suggest [7, 8]: 1. the severity of MV obstruction correlates with poor long-term outcome. 2. MV obstruction is the limiting factor for biventricular repair. * Adeline Walter 1 Department of Obstetrics and Prenatal Medicine, University Hospital Bonn, Venusberg‑Campus 1, 53127 Bonn, Germany 3. the need for MV intervention shortly after initial aortic valve/isthmus correction significantly increases the risk of neonatal death. 4. substantial morbidity related to arrhythmias, heart failure and intervention in adulthood advocate rigorous follow-up [9–11]. To date, prenatal data on PMV/PLMV are rarely reported and fetal structured evaluation analyzing the mitral valve complex, consisting of mitral valve annulus, anterior and posterior leaflets, chordae tendineae and papillary muscle, is not well understood [12–14]. Therefore, published studies with contradictory results on fetal detection of PMV/ PLMV are not surprising, with some stating that valvular and subvalvular morphological alteration with a Doppler gradient over the MV are only detectable postnatally and others reporting on prenatal observable abnormalities [6, 15, 16]. In our experience, we noticed pattern recognition for fetal PMV to be feasible, once the pathognomonic echocardiographic characteristics are identified. As fetuses might be at risk of an incorrect diagnosis in case of suspected isolated LVOT obstruction, a more profound examination of the MV is needed. We present a case of prenatal diagnosis of PMV with Shone complex and tried to provide an example and a diagnostic algorithm to use in case of uncertainty. Case A 28-year-old-woman was referred to our department at 20+4 weeks gestation because of a suspected cardiac anomaly. Fetal echocardiography revealed diagnosis of Shone complex, as CoA, subaortic stenosis, and small left ventricle combined with a parachute mitral valve was found. After multidisciplinary counseling, including by the pediatric cardiac surgeon, parents decided to terminate the pregnancy at 21+4 weeks. Postmortem examination was refused by the parents (Fig. 1). Vol.:(0123456789) Archives of Gynecology and Obstetrics Fig. 1  Prenatal sonographic examination of a parachute mitral valve (PMV) (a–e) in comparison to a normal mitral valve (MV) (f–j); a four chamber-view of the fetus at 20 + 4 weeks of GA displaying disproportions of the left heart structures compared to right heart-sided structures (RA > LA width in systole; RV > LV; RV 5.4 mm, + 1.19 z-score; LV: 4.2 mm,− 1.6 z-score), as associations to LVOT obstructions are frequently seen. a, b Same fetus with the four chamberview showing the extreme narrow mitral orifice, typically eccentric (3.1 mm, − 4.8 z-score; TV/MV ratio: 1.9). In diastole, the redundant anterior chords fold over on themselves, appearing as swirling echogenic patterns in the LV (dotted arrow in b). Further, the typical paradoxical movement of the interventricular septum bowing into the perimembranous part of the interventricular septum is demonstrated (continuous arrow in b). c, d Parasternal short-axis view demonstrating typical aspects of the single papillary muscle (dotted circle in c) of the mitral valve, with a restricted opening (dotted circle in d). e Echocardiographic parasternal long-axis view showing a single papillary muscle inserting to the leaflets by short and thickened chordae tendineae (arrow). f–j Normal findings of an unsuspicious MV. f, g Four chamber-view with an unsuspicious LV:RV proportion; normal centrally positioned mitral orifice and an absent excursion of the IVS in diastole. h, i Parasternal short-axis view at the mitral valve level showing both papillary muscle groups (posteromedial papillary muscle (PMPM) and anterolateral papillary muscle (ALPM) with an unrestricted orifice appearing as a “fish mouth”, demonstrating a not restricted opening of the valve. j Regular parasternal long-axis view showing unsuspicious chordae tendineae (arrow). LA left atrium, LV left ventricle, MVmitral valve, PMPM posteromedial papillary muscle, RA right atrium, RV right ventricle Discussion be performed in all cases, if any LVOT obstruction is suspected, in order not to miss Shone complex. In these cases, the four chamber-view (4CV) and three-vessel trachea view (3VT) are typically highly suspicious for CoA and the examiner should set up for detailed evaluation of a possible PMV (Fig. 2) including parasternal short-axis and long-axis views. The provided diagnostic algorithm for With an increasing sophistication in ultrasound technologies, an accurate detection of the papillary muscles with description of their malformations is feasible, but requires prior knowledge of the normal anatomy and abnormal variants. Although not yet standard clinical practice, a structured evaluation of the mitral valve complex should Archives of Gynecology and Obstetrics Fig. 2  Diagnostic algorithm for prenatal suspected parachute mitral valve. IVS interventricular septum, LA left atrium, LV left ventricle, MV mitral valve, PMPM posteromedial papillary muscle, RA right atrium, RV right ventricle, TV tricuspid valve suggested PMV can be used to help confirm the prenatal diagnosis of P (...truncated)