[Ruptured chordae tendineae of tricuspid valve in neonate with intractable persistent pulmonary hypertension: a case report and literature review].

To analyze the clinical characteristics and treatment of tricuspid valve prolapse caused by chordal rupture complicated with persistent pulmonary hypertension in neonates. The clinical data of a male neonate with tricuspid valve prolapse complicated with persistent pulmonary hypertension admitted to the Neonatal Intensive Care Unit of Children's Hospital of Hebei Province in November 2018 was analyzed retrospectively. Related literature up to September 2020 was searched with the strategy of "(neonate OR newborn) AND (tricuspid valve prolapse) AND (rupture OR necrosis) AND (papillary muscle OR chordae tendineae) AND (pulmonary hypertension)" in Wanfang, CNKI and PubMed database in Chinese and English. The characteristics of the disease were summarized. A male full-term neonate was admitted due to presenting severe cyanosis for 9 hours. He was born by caesarean section and presented severe cyanosis and dyspnea at 10 min of ages, unresponsive to the positive airway pressure resuscitation. After 9 hours of mechanical ventilation, there was no improvement. Thus he was transferred to Children's Hospital of Hebei Province. On admission, the initial blood gas analysis showed an arterial partial pressure of oxygen of 22.5 mmHg (1 mmHg=0.133 kPa). The echocardiography revealed prolapsed anterior leaflet of tricuspid valve, severe tricuspid regurgitation (TR) and pulmonary artery hypertension, and right to left shunt via a patent foramen ovale. The arterial duct was closed. The chest X-ray was normal. The boy was treated with nitric oxide, milrinone, and continued mechanical ventilation initially. Addition of prostacyclin analog (treprostinil) on day 3 led to significant improvement of pulmonary blood flow, oxygenation, and stabilization, so that the extracorporeal membrane oxygenation therapy was avoided. At 11 months after birth, the boy underwent cardiac surgery. At surgery, the rupture of chordal tendineae in anterior leaflet of tricuspid valve was found. Tricuspid annuloplasty, valvuloplasty and repair of patent foramen ovale were successfully performed. The follow-up echocardiogram at postoperative 3 months showed only mild tricuspid insufficiency. The boy was well at last follow-up at 22 months of age with normal cognitive skill development. According to literature, 20 cases of papillary muscle or chordae tendineae rupture in neonates had been reported in 12 English papers. Among the total 21 neonates, there were 12 male infants and only one premature infant with gestational age of 33 weeks. They presented with profound cyanosis soon after birth. All of them received endotracheal intubation and mechanical ventilation. Other treatments included inhalation of nitric oxide, intravenous milrinone, vasoactive drugs, diuretics and prostacyclin, etc. Extracorporeal membrane oxygenation (ECMO) was used in 6 infants as a bridge to surgical treatment. Two cases reported earlier death of cardiopulmonary failure without operation and the rest 19 survived after surgery. The followed surgery or autopsy revealed that all of them had tricuspid valve prolapse, rupture of papillary muscle or chordae tendineae. The severe TR resulting from rupture of papillary muscle or chordate tendineae in neonates is rare and could cause severe hypoxemia. Early recognition, adequate cardiopulmonary support to stabilize the hemodynamic status and timely surgery can significantly reduce the mortality.