The Clinical Study Of Quantitative Flow Ratio In Guiding Of Drug-coated Balloon In Interventional Therapy Of Coronary Artery Disease

Background and Objective:Fractional flow reserve(FFR),an important indicator for assessing coronary blood flow insufficiency,is of great significance in guiding percutaneous coronary intervention(PCI)and improving prognosis of patients.As a continuous variable,the FFR value post PCI is also closely related to the prognosis of patients.Previous studies reported that the FFR value post PCI>0.9,which is the ideal boundary value,indicated that the major adverse cardiovascular events(MACE)are low in the following 6-12 months.Quantitative flow ratio(QFR)is a non-invasive FFR-simulating technique that has been developed in recent years.It simulates FFR values through three-dimensional quantitative coronary angiography(QCA)and computational fluid dynamics.Series of studies have confirmed preoperative QFR and FFR have a good correlation and consistency.However,there is no study on the efficiency of QFR in evaluation of coronary blood flow after PCI.The drug coated balloon(DCB)is an interventional instrument for delivering the anti-proliferation drug paclitaxel into endothelial cells and inhibiting proliferation by using a semi-compliant balloon as a carrier.It was firstly implemented to treat in-stent restenosis(ISR),and significantly reduced postoperative target lesion restenosis without increasing metal stent implantation.Then many international guidelines and consensus recommended it as a preferred treatment in solving ISR.However,the failure rates of target lesions revascularization after DCB treatment in ISR are still as high as 20%.There is no systemic study on the risk factors analysis for treatment failure.Nowadays,DCB are also applied to the treatment of de novo lesions including small vessel disease,side branch lesions and clinical conditions not suitable for stent implantation.How to optimize the efficacy and improve the safety of the DCB treatment is still an important issueMethodsThe first part:62 patients measured FFR value immediately after PCI were retrospectively enrolled in our hospital from January 2015 to October 2018.We analyzed postoperative FFR value distribution,then reconstructed three-dimensional coronary angiography and calculated QFR value of the target vessels.We evaluated the correlation and consistency between post-operative QFR and final FFR.Then,by using post-PCI FFR value as the gold standard of coronary physiology evaluation,we established receiver's operating characteristic curve(ROC curve)to evaluate diagnostic efficiency of residual stenosis of lumen area,fixed model-derived fQFR and contrast-corrected cQFR.The second part:a total of 209 cases and 228 lesions concerning DCB treatment for ISR,including data from the RESTORE ISR study,were enrolled and analyzed.By using angiographic definition of ISR as the criterion,we divided follow-up patients into target lesion failure group(43 cases)and target lesion success group(166 cases).The clinical and angiographic characteristics of preoperative and intraoperative were analyzed,and QFR at various time points before and after PCI were also calculated.Then we performed multivariate logistic regression analysis and ROC curve to analyze(1)independent risk factors for target lesion failure after DCB treatment for ISR;(2)coronary physiology indicators measured by QFR value before and after PCI in predicting the risk of target lesion failureThe third part:Focusing on DCB treatment for de novo lesions in coronary artery disease,we consecutively enrolled 84 patients and divided them into ideal pretreatment group(post-pretreatment QFR>0.85,n=62)and suboptimal pretreatment group(post-pretreatment QFR<0.85,n=22),then we established a cohort and performed clinical and angiographic follow-up for 6-12 months.To optimize the treatment strategy of DCB in de novo lesions,the MACE rates and angiographic characteristics including relative diameter stenosis(DS%),late lumen loss(LLL),and net gain of lumen,based on QCA analysis,were recorded and compared between two groupsResultsThe first part:the distribution of FFR values after PCI showed heterogeneity.Only 45.5%FFR value of target vessels achieved ideal physiologic reconstruction(FFR>0.9).Postoperative cQFR values showed a good correlation with FFR values(r=0.74,P<0.0001)and good consistency(P=0.47).The diagnostic accuracy of cQFR was the best among all parameters in the ROC established by using postoperative FFR as gold standard(AUC=0.867,P<0.0001).The diagnostic threshold value of postoperative cQFR for ideal functional revascularization was 0.905,through which we measured diagnostic sensitivity of FFR>0.90 as 91.6%,the specificity as 70%,and the accuracy as 80%.The second part:through comparing clinical and angiographic characteristics between TLF group and non-TLF group,we found that the proportion of small vessel disease(57.1%vs.40.8%,P=0.041),lesion length(17.6±5.9 mm vs.15.3±5.4 mm,P=0.012),target vessel diameter(2.83±0.34 mm vs.2.98±0.41 mm,P=0.021),initial luminal area stenosis(87.8±6.5%vs.84.6±9.3%,P=0.023),luminal area stenosis after balloon pretreatment(34.4±10.7%vs.30.1±11.8%,P=0.039),DCB diameter(2.82±0.33 mm vs.2.98±0.41 mm,P=0.021),DCB length(23.1±5.5 mm vs.20.8±5.2 mm,P=0.008),initially angiographic QFR of target vessel(0.56±0.22 vs.0.69±0.20,P<0.0001),QFR after DCB treatment(0.89±0.09 vs.0.96±0.04,P<0.0001)were all significantly different in statistics.Logistic multivariate regression analysis revealed that lesion length(OR=1.079,P=0.021)and initial luminal area stenosis(OR=1.069,P=0.014)were independent risk factors for target lesion failure,while both initial QFR and final QFR after DCB treatment had prognostic value in predicting target lesion failure.Through performing ROC curve to evaluate the effciency of different factors in predicting target lesion failure,we found that final QFR after DCB treatment had the best predictive value of ISR prognosis(AUC=0.792,P<0.0001),with the cut-off point of 0.90.The third part:through comparing clinical endpoints 6-12 months after DCB treatment of de novo lesions,we found that MACE frequency,mainly target lesion revascularization(TLR),was much lower in the ideal pretreatment group measured by QFR(4.8%vs.36.4%,P<0.0001).The QCA analysis showed that the DS%of the ideal pretreatment group was significantly lower than that of the suboptimal pretreatment group(28.1±13.1%vs.48.4±27.7%,P<0.0001),and the LLL showed the same trend(0.14±0.19 mm vs.0.38±0.46 mm,P=0.002),while the net benefit of lumen diameter showed an opposite trend(0.70±0.36 vs.0.47±0.42 mm,P=0.019)Conclusions:1.There is heterogeneity of FFR value after PCI,meaning only part of the target vessels achieved ideally physiological revascularization.A good correlation and consistency between cQFR and FFR can be found,and cQFR>0.905 is the value of ideally physiological reconstruction after PCI(FFR>0.90)2.The independent risk factors of TLF in ISR treatment was:lesion length(OR=1.079,P=0.021)and initial luminal area stenosis(OR=1.069,P=0.014).Meanwhile,the improvement of coronary physiologic function characterized by QFR post DCB treatment was an important predictor for treatment success.3.In DCB treatment of de novo lesions,the pretreatment effects measured by QFR are vital for optimal strategy selection.Ideal pretreatment(QFR>0.85)is suitable for only DCB strategy,whereas strategy of suboptimal pretreatment(QFR<0.85)should be converted to stent implantation instead.