Nitinol Patent Ductus Arteriosus Occluder

Patent ductus arteriosus (PDA) is one of the most common congenital cardiovascular anomalies in children, accounting for approximately 5%–10% of all congenital heart defects.

During fetal development, the ductus arteriosus shunts blood from the pulmonary artery to the aorta, thereby allowing systemic perfusion without passing through the non-functional fetal lungs. Under normal circumstances, the ductus arteriosus closes functionally within 48 hours after birth in most full-term infants and undergoes anatomical closure within three months.

However, when the ductus arteriosus remains persistently open after birth, it results in left-to-right shunting, leading to a series of complications such as congestive heart failure, infective endocarditis, and obstructive pulmonary hypertension. In severe cases, the condition may be life-threatening. Therefore, timely intervention for PDA carries important clinical significance.

PDA can be classified according to its anatomical morphology into the following types:

The anatomical types of PDA include:

Funnel-shaped type: Characterized by a wide aortic end and a narrow pulmonary end; this configuration is commonly observed.
Window type: The least common type, in which the descending aorta and main pulmonary artery lie adjacent to each other, forming a “window-like” connection.
Tubular type: The most frequently encountered morphology, featuring a relatively long ductus with similar internal diameters at both ends. The ductal length typically exceeds its internal diameter.

Transcatheter closure of PDA has been practiced for more than 50 years and is associated with advantages such as fewer complications, shorter recovery time, and lower medical costs. With advancements in medical technology and material science, transcatheter occlusion has gradually replaced traditional surgical ligation via thoracotomy and is now considered the first-line treatment for PDA in infants weighing ≥5 kg and in pediatric patients.

PDA Closure Device

Over the past year, the significance of nickel–titanium (Nitinol) alloys in medical technology has continued to grow, accompanied by increased investment and expansion in the industry’s manufacturing capabilities for Nitinol-based materials and components. Owing to its exceptional superelasticity, shape-memory properties, and biocompatibility, Nitinol has demonstrated tremendous potential across a wide range of medical applications.

In 2025, the use of Nitinol continues to expand, playing an increasingly critical role particularly in cardiovascular and structural heart disease devices. Its unique mechanical and biological advantages make it one of the most important materials driving innovation in modern minimally invasive medical technologies.

Material and Structural Features

Nitinol Braided Mesh Framework

The occluder is constructed using a braided mesh made of nickel–titanium (Nitinol) alloy wires, a material well known for its excellent elasticity, shape-memory characteristics, and biocompatibility. The superelastic properties of Nitinol enable the device to maintain stability within complex anatomical structures and accommodate vascular motion, thereby minimizing trauma to surrounding tissues.

Occlusive Membrane Structure

The device incorporates a densely woven occlusive membrane capable of effectively blocking abnormal blood flow through the patent ductus arteriosus. This design ensures a high immediate occlusion rate, helping to rapidly achieve closure and reduce the risk of postoperative residual shunting.

Design Advantages

Secure Conformability and Fixation

The occluder is engineered to conform closely to the PDA anatomy and anchor securely within the ampulla of the ductus. This precise fit ensures device stability and effectiveness in vivo, significantly reducing the risk of migration.

Minimal Impact on Blood Flow

The geometry and structural design of the occluder minimize interference with blood flow in both the aorta and pulmonary artery. This is essential for preserving normal hemodynamics, particularly in children and preterm infants, who are more sensitive to alterations in circulatory dynamics.

Long-Term Stability

With excellent fatigue resistance, the occluder maintains structural stability over long-term physiological conditions. This durability is crucial for ensuring sustained therapeutic effectiveness and lowering the risk of long-term complications.