Opening a New Door for Heart Disease Patients: The Breakthrough Story of China's First Balloon-Expandable Aortic Valve

Original Title: Opening a “New Door” for Heart Disease Patients—A Record of the Breakthrough in Developing China’s First Balloon-Expandable Aortic Valve

[Innovation Story]

◎ By our reporter Fu Lili

On the operating room’s imaging screen, a prosthetic valve is slowly advanced along a slender catheter toward a heart that has been beating for over 80 years and is riddled with calcified lesions. This elderly patient presents a high-risk clinical profile: critical aortic stenosis, seven previously implanted coronary stents, and a history of cerebral hemorrhage—each factor rendering traditional open-heart surgery contraindicated.

The catheter navigated past tortuous vessels, smoothly reaching the lesion site for positioning and deployment. The new valve bloomed like a flower, firmly anchored onto the severely calcified annulus. Recently, this high-difficulty procedure was successfully performed using a domestically produced balloon-expandable aortic valve (hereinafter referred to as the "balloon-expandable valve").

The aortic valve acts as the “valve” for the heart’s blood pumping; once it malfunctions, life is immediately at risk. For high-risk patients who cannot undergo open-chest surgery, transcatheter aortic valve replacement (TAVR) is their last hope. However, this field has long been monopolized by foreign companies. “We assembled a research and development team and spent seven years tackling key challenges, breaking through technical bottlenecks one by one in areas such as the valve frame, leaflets, and delivery system, completely reversing this situation,” Yu Qifeng, Chairman of Shanghai NewMed Medical Co., Ltd., told reporters from Science and Technology Daily.

Precision-Carved Skeleton

The first step in developing a balloon-expandable valve is to design the skeleton that supports the valve’s function—the stent frame. From the outset, the R&D team focused on cobalt-chromium alloy. This material offers excellent biocompatibility and strong radial support, enabling the fabrication of thinner and finer stents, thereby minimizing damage to the vessel wall.

However, the extreme hardness of cobalt-chromium alloys makes processing them into hair-thin stents a challenge beyond imagination. “This is the root reason why domestic enterprises have hesitated to attempt this for many years,” admitted Wang Haishan, the team’s chief engineer.

To address the challenge, Wang Haishan led a team to Germany for training. Everyone had assumed that mastering the foreign manufacturer’s processing techniques would resolve the laser cutting dilemma, but reality dealt them a heavy blow.

Upon returning to China, the first trial ended in failure. Subsequently, the team closely monitored every cutting test, with the blue light of the equipment often staying on throughout the night. On countless nights, Xiao Zhenxin, a team engineer, stood guard before the equipment, intently watching the laser beam dancing on the cobalt-chromium alloy tubing—where success or failure hinged on deviations as fine as the diameter of a human hair. Behind him, failed samples piled up from the workbench to the corner of the room, totaling over a thousand pieces.

“Foreign processing methods proved unworkable, leaving us no choice but to start from scratch,” recalled Yu Qifeng. Over the next three months, the team practically “welded” themselves to the workshop floor. At that time, the laboratory was cramped and confined; five engineers squeezed into the space, barely able to turn around. The sweltering summer heat, compounded by equipment heat dissipation, made the interior as stifling as a steamer basket. Though drenched in sweat, everyone persevered silently.

After repeated trial and error, the team identified laser path programming as the core challenge. Xiao Zhenxin marked hundreds of entry points on the drawings with a pencil, manually connected the paths, and then imported them into the computer. Laser energy, travel speed, focal distance... each parameter underwent hundreds or even thousands of adjustments, yet the experiments still failed to succeed.

Late into another night, after repeatedly comparing the “heat-affected zones” of failed samples, Xiao Zhenxin boldly decided to reduce the laser energy by 5%, slow down the cutting speed by 10%, and incorporate pre-compensation trajectories in the programming to account for the thermal expansion coefficient of cobalt-chromium alloy.

As the laser beam completed its traversal along the tubing, Wang Haishan held his breath and placed the sample under a microscope. The edges of the slender diamond-shaped leaflet frame appeared smooth and polished, with all nodal dimensions meeting the required specifications.

Amidst the excitement, there was still a sense of unease. The samples faced their ultimate test—fatigue testing.

After 400 million simulated beats, the valve frame remained robust. “It’s a success!” Several men couldn’t help but cheer with joy. This is equivalent to the heart beating continuously and stably at a frequency of 70 beats per minute for nearly 11 years.

Refined Leaflets

With a robust “iron frame,” a flexible “gateway” is also essential—the leaflets. As the core component of the valve, they directly determine its opening and closing function, service life, and patient safety.

The R&D team found that the structure of bovine pericardial valves is closer to that of the human body, and their hemodynamic performance is superior to porcine heart valves used in some imported products.

Initially, they pinned their hopes on yak pericardium. To this end, the team traveled to Hongyuan County in Aba, Sichuan, to select materials. “Altitude sickness struck one after another; many team members successively experienced discomforts such as headache, vomiting, and dyspnea, leaving them nearly physically exhausted,” said Yu Qifeng.

On-site inspections revealed that although the quality of yak pericardium was satisfactory, the dispersed local slaughterhouses and inadequate cold-chain infrastructure made it difficult to ensure batch-to-batch consistency of raw materials. After careful consideration, the team had no choice but to reluctantly abandon the project.

Subsequently, they shifted to selecting healthy bovine pericardium from specific age groups, subjecting each piece to multiple rigorous screening steps, including visual inspection, thickness measurement, mechanical tensile testing, and density assessment. Only “gold-standard” raw materials with uniform thickness and excellent toughness were retained. “Each piece of raw material must be carefully screened as if selecting jewelry,” recalled Cheng Xiulan, a team member.

Having just cleared the hurdle of raw material procurement, the team faced an even more daunting challenge: leaflet suturing. The early pass rate for suturing was dismally low. Variations in technicians’ skills and experience led to inconsistent quality, severely impeding the R&D progress. “We had been relying on individual empirical feel, lacking millimeter-level standardization,” Cheng Xiulan stated candidly.

At a critical juncture, Wang Chunyang, the team’s clinical engineer, proposed a novel approach: “Although wound closure and leaflet suturing are applied in different scenarios, their underlying logic of precision manipulation may be mutually informative.”

A Battle for “Standardized Manual Suturing” Has Begun. Under the shadowless surgical lights, technicians hold micro-forceps and suturing needles, holding their breath in intense concentration. The valve leaflets are as thin as cicada wings and possess a pliable texture; every stitch must be executed with zero deviation. They repeatedly tested hundreds of suturing pathways, adjusted suture tension, and optimized knot-tying techniques.

After more than 180 days, the team developed a unique suturing standard: after identifying the center point of the leaflet, the suture must be knotted within 0.8 mm from the edge, and then started within 0.5 mm from the clip edge, precisely stitching the three leaflets in a straight line. This approach boosted the leaflet qualification rate to over 95%, with precision and durability matching international top standards.

“At that moment, we knew this ‘heart’ could beat,” said Yu Qifeng with emotion.

Crafting Pathways

With the challenges of the valve frame and leaflets successively overcome, the valve took its preliminary shape. However, how could it be implanted into the heart with precision and safety? As the “lifeline” of the valve, the delivery system became another formidable barrier facing the team. Its flexibility for smooth passage and accuracy in positioning directly determine the success or failure of the surgery.

During the early stages of research and development, the delivery system designed according to conventional approaches repeatedly failed in experiments. After several rounds of adjustments, Wang Haishan and three engineers took the optimized delivery system to the Shanghai Animal Testing Center for validation testing. However, the outcome was deeply disappointing—due to inadequate fine-tuning of the delivery angle, the pericardial vascular wall was accidentally damaged.

“We can only find the answers on the clinical frontline.” As a profound sense of frustration enveloped the team, Qin Tao, the team leader, offered words that struck a chord and awakened everyone. A former clinician himself, he knew well that rather than working in isolation in the laboratory, it was better to listen to the real pain points from the surgical frontline to identify the direction for breakthroughs.

Yu Qifeng sent the animal trial imaging data overnight to Professor Chen Mao’s team at West China Hospital, Sichuan University. Unexpectedly, feedback was received the following morning: “Your delivery system has only one radiopaque marker, making it difficult to accurately determine its position during the procedure.”

Everyone had a sudden realization. “Since one point is insufficient, let’s set up several more,” Qin Tao proposed.

After repeated calculations of the cardiac anatomy and the delivery path for the balloon-expandable valve, the team not only placed radiopaque markers every 2 millimeters along the delivery system but also creatively designed an interconnected fine-tuning knob and a precise scale on the control handle. “With real-time guidance from digital subtraction angiography, physicians can position and deploy the valve with micrometer-level precision, much like driving a car while watching the dashboard,” explained Wang Chunyang.

To enable the delivery system to safely navigate tortuous vessels with the agility of a supple snake, the team, drawing on clinical practice, mastered “adjustable curvature technology.” This innovation allows the distal end of the delivery system to flexibly “steer,” facilitating easy passage through the aortic arch and automatic angle adjustment upon reaching the heart, thereby ensuring precise valve deployment in a perpendicular orientation.

After 2,497 days and nights of sustained research and development, the R&D team turned one “impossible” after another into reality, successfully creating China’s first domestically produced balloon-expandable valve.

“Exquisite design stems from the deep integration of clinical practice and research and development; only by translating clinical pain points into engineers’ blueprints can innovation truly take root.” Looking to the future, Yu Qifeng stated with determination, “We are confident that in the next seven years, we will make domestically produced heart valves benefit people in China and expand into overseas markets, allowing the world to feel the ‘beating’ power of Chinese heart valves.” (Fu Lili)

Original Title: Opening a “New Door” for Heart Disease Patients—A Record of the Breakthrough in Developing China’s First Balloon-Expandable Aortic Valve Source: Science and Technology Daily