Peri and intraglomerular haematoxylinophilic deposits in a newborn: question

A female preterm infant, weighing 2,480 g, was born in a first level Hospital, with caesarean section performed for acute fetal distress. The mother, a 34 years old woman, had a previous healthy child. At birth the general conditions were good. At cardiological examination a patent ductus arteriosus was diagnosed. Laboratory values were within normal range. The newborn was discharged after 11 days, in good general conditions and with spontaneous feeding. During a planned cardiologic follow-up control at day 50, cardiac ultrasounds revealed an increase of volume of left atrium and ventriculus, which appears severely hypokinetic. The baby was urgently transferred in a NICU, where she died after 12 hours for heart insufficiency. At autopsy, deposition of amorphous material, mainly stained by haematoxylin, in periglomerular location was found in the kidney. 1. What is your morphological diagnosis? 2. Which complementary investigations do you suggest? 3. Could be important the examination of large and medium-sized arteries in the heart?