A multi-disciplinary team of PUMCH led by Vascular Surgery was the world first to apply iFlow+PBV, a new imaging technology, to the treatment of renal artery and below-knee arterial stenosis. It established safe and stable measurement for blood vessel perfusion and, using only a small radiation dose and contrast agent, was able to measure accurately flow speed, volume and perfusion during operations. The team quantified surgical indications and optimized plans constantly during operations to ensure better treatment. The project won third prize of 2018 PUMCH Award of Medical Achievement Transformation.
Changes in people's diet and lifestyle have given rise to the "three highs": high blood pressure (hypertension), high blood glucose (hyperglycaemia), high blood lipid (hyperlipidaemia) and the occurrence of atherosclerosis kept increasing. Atheroma, stenosis and even closure of renal artery will lead to less blood flow in the kidney and damaged functions; it may also lead to large release of rennin, systemic small artery contraction and cause renal hypertension. Besides, takayasu arterifis, which is often found among the young, might also cause renal artery stenosis. Below-knee arterial stenosis will cause local shortage of blood in shanks and feet. Patients would have cold, numb and swollen parts, and even ulceration and necrosis. Vascular intervention is the top option, and the key is to increase blood supply in these parts. However, conventional therapies had been focusing on vessel opening, and were unable to assess micro-circulation improvement and scientifically predict post-operation effects.
Vascular Surgery applied iFlow+PBV innovatively to the treatment of renal artery and below-knee arterial stenosis. Through iFlow+PBV, doctors could obtain real-time DSA data during operations, combine them into a colored image and analyze perfusion parameters of peripheral tissues. Since 2016, the team has performed more than 70 surgeries and, while ensuring patient safety, carried out verifications on operational procedures, contrast agent time, contrast agent dose, injection method and speed, imaging time and measurement locations. It set up the world’s first standardized measurement method of peripheral tissue perfusion and provided guidance for the technique's clinical application and promotion. It has been proven that iFlow+PBV is safer and has lower kidney damage and burden. It only needs 1/10 of contrast agent as required in conventional CT imaging. Under the radiation of conventional vascular surgery, each imaging only takes around 10 seconds.
Using data from the technique, the team further quantified disease classification and surgery indications. In the treatment of renal artery stenosis, the team found that if kidney perfusion was less than 300 PU, a surgery would remarkably improve kidney functions. Taking “less than 300 PU” as a surgical indication, the team avoided unnecessary treatment for patients who didn’t reach this standard, and allowed those having operations to receive expected benefits. In the treatment of below-knee arterial stenosis, the team rated patients according to their symptoms, before-operation flow speed and perfusion, to assess the seriousness so as to decide on surgical plans and maximize benefits.
The results were widely accepted by vascular surgery communities at home and abroad. It won the Best Innovation Award at the 2016 IUA Annual Meeting. The team was invited to give a speech at 2017 Veith meeting, which was hosted by the International Society for Vascular Surgery and attended by more than 50 countries, and won the second place in essay competition, being the only winner from China. Related project was supported by Beijing Municipal Science and Technology Commission and PUMCH youth fund, with six English essays published on SCI journals and three on Chinese core journals.
According to Professor Liu Bao, deputy director of Vascular Surgery , the significance is the shifted focus from vessel openness to tissue perfusion. iFlow+PBV not only boosted clinical effects but improved prediction of prognosis, and, as a breaking through point in pathological and other clinical researches, is of great value in clinical application and promotion.
iFlow shows changes in kidney perfusion before and after operation.
iFlow shows feet perfusion before and after operation. Follow-up shows healed ulceration.