Ability of Fractional Flow Reserve to Predict Restenosis After Superficial Femoral Artery Stenting

Impact of post-procedural peripheral fractional flow reserve after drug-coated balloon angioplasty in femoropopliteal lesions

PURPOSE

The aim of this study was to determine if postprocedural peripheral fractional flow reserve (pFFR) is associated with patency one year after drug-coated balloon (DCB) angioplasty for femoropopliteal (FP) lesions.

MATERIALS AND METHODS

Forty-five consecutive patients having 49 de novo FP lesions were enrolled in this prospective, observational study conducted from April 2022 to Aug 2023. The pFFR was measured under hyperemic conditions after the administration of 30 mg of papaverine. The relationship between pFFR and restenosis 12 months after the procedure was determined using receiver operating characteristic (ROC) curve analysis.

RESULTS

The one-year follow-up was completed for 47 lesions (95.9 %). Restenosis was detected in 7 lesions (14.9 %). Postprocedural pFFR was significantly higher in the nonrestenosis group compared with the pFFR in the stenosis group (0.95 ± 0.054 vs. 0.88 ± 0.090, p = 0.010). The optimal pFFR cutoff value for predicting restenosis was 0.92 (sensitivity, 0.824; specificity, 0.600). The area under the curve for pFFR was numerically higher than the area under the curve for minimum lumen area (0.73 vs. 0.64, p = 0.22). Rates of freedom from restenosis at one year were significantly higher in the pFFR >0.92 group compared with the pFFR ≤0.92 group (p = 0.0042).

CONCLUSION

Postprocedural pFFR was associated with patency at one year after DCB angioplasty for FP lesions.

Effectiveness of intra-arterial manometry in guiding femoral popliteal stent implantation: a prospective randomized controlled trial

BACKGROUND

Femoropopliteal artery occlusion is a prevalent peripheral arterial disease, and endovascular therapy has become the preferred treatment. Accurate assessment of balloon dilation efficacy is crucial for determining the necessity for subsequent stent implantation. This study aims to investigate the use of interlesion arterial pressure gradients as a novel approach to assess balloon dilation efficacy and guide stent implantation decisions.

METHODS

A prospective, randomized, controlled trial was conducted on 100 patients with femoropopliteal artery occlusion. Patients were randomized into a control group (n=50) and an experimental group (n=50). Stent implantation was performed in the control group according to standard indications, while the experimental group underwent stent implantation only if the mean arterial pressure gradient exceeded 10 mmHg or fractional flow reserve (FFR) fell below 0.85. Post-intervention, pressure measurements and angiography were used to evaluate residual stenosis, dissection, and pressure gradients.

RESULTS

Lesions were categorized into stent-indicated and non-indicated groups. In the non-stent-indicated lesions, the experimental group demonstrated significantly higher patency rates for lesions with pFFR < 0.85 or ΔP > 10 mmHg compared to the control group (92.9% vs. 50.0%, P=0.039). There was no significant difference in patency rates between the experimental and control groups for stent-indicated lesions.

CONCLUSION

Combining pressure measurement with angiography provides a more precise evaluation of balloon dilation efficacy and stent implantation indicators in femoropopliteal artery occlusive disease. Further research is needed to establish optimal pressure threshold values and refine treatment guidelines.

Utility and optimal dose of nicorandil for physiological assessment of the femoropopliteal artery

BACKGROUND

Nicorandil is widely used as a vasodilator for the physiological assessment of coronary arteries because of its usefulness and safety; however, there are no data on its use in peripheral arteries.

AIMS

To identify the utility of nicorandil and its appropriate dose for the physiological assessment on the femoropopliteal artery.

METHODS

We retrospectively enrolled patients from three institutes in which physiological assessment was carried out with various doses of nicorandil before treatment. Twenty-four femoropopliteal artery stenotic lesions from 22 patients were included. The nicorandil doses used were 2, 4, and 6 mg. Twenty-two lesions were also assessed using 30 mg of papaverine. The pressure gradient (PG) and peripheral fractional flow reserve (pFFR) were calculated based on the mean and systolic pressure levels. We examined the correlation of each parameter with the peak systolic velocity ratio (PSVR) based on the duplex ultrasound images using Spearman's rank correlation coefficient. Systemic blood pressure was assessed for safety.

RESULTS

The correlations were higher for mean pressure-based parameters than for systolic pressure-based parameters. As the nicorandil dose increased, the correlations among PG, pFFR, and PSVR also increased (mean pressure-based PG: 2 mg, r = 0.360; 4 mg, r = 0.498; 6 mg, r = 0.694, mean pressure-based pFFR: 2 mg, r = -0.479; 4 mg, r = -0.469; 6 mg, r = -0.641). The blood pressure after the administration of 6 mg of nicorandil was low, and the median systemic mean pressure was 65 mmHg.

CONCLUSION

A 4 mg dose of nicorandil is effective and safe for the mean pressure-based physiological assessment of lesions in the femoropopliteal artery.

Correlation between physiological assessment and imaging findings during drug-coated balloon treatment for femoropopliteal diseases

BACKGROUND

This prospective cross-sectional study evaluated the correlation between physiological assessment (PA) and minimum lumen area (MLA) by intravascular ultrasound (IVUS) during drug-coated balloon (DCB) treatment for femoropopliteal (FP) diseases.

METHODS

A total of 51 limbs of 44 patients undergoing endovascular treatment with DCB for de novo FP disease were examined from April 2022 to February 2023. PA was conducted at baseline, after balloon dilatation, and after DCB treatment. PA was measured before (pressure ratio; PR) and after vasodilation (peripheral flow fractional flow reserve; pFFR) with the administration of 30 mg papaverine through a guiding catheter. The correlation of PA with percent diameter stenosis (%DS) and MLA was examined, and factors correlated with higher pFFR after balloon dilatation were evaluated in a multivariate analysis.

RESULTS

At baseline, there were correlations between pressure ratio (PR) and %DS (coefficients: 0.641 [p < 0.001]) and between pFFR and %DS (0.666 [p < 0.001]). After balloon dilatation, there was no correlation between PR and %DS (coefficients: 0.33 [p = 0.27]) or between pFFR and %DS (0.41 [p = 0.71]). At baseline, PR and MLA were correlated (coefficients: 0.757 [p < 0.001]) as were pFFR and MLA (0.762 [p < 0.001]). After balloon dilatation, PR and MLA were correlated (coefficients: 0.524 [p < 0.001]) as were pFFR and MLA (0.601 [p < 0.001]). Balloon/EEM ratio, calcification >270°, and chronic total occlusion were associated with pFFR after balloon dilatation.

CONCLUSION

After balloon dilatation, PA was correlated with MLA by IVUS but not with %DS based on angiography.

Efficacy of pressure gradient measurement using peripheral fractional flow reserve in common femoral artery: a case report

Background

The severity of peripheral artery disease (PAD) is usually diagnosed by physiological assessments, such as the ankle brachial index (ABI) or peak systolic velocity (PSV) on ultrasonography. We examined peripheral fractional flow reserve (pFFR: distal mean pressure divided by proximal mean pressure) measured by a pressure wire and pressure gradient to diagnose PAD patients who do not have lowered ABI or high PSV on ultrasonography.

Case summary

An 84-year-old woman with intermittent claudication in her left leg had severe calcification in the left common femoral artery (CFA) on angiography. The exercise-stress ABI of pre-endovascular therapy (EVT) was 1.05/0.98. In addition, the PSV of the left CFA on ultrasonography was 230 cm/s. However, the pFFR using papaverine and alprostadil in the left CFA was 0.86, which was a significant score. In addition, the systolic pressure gradient between the distal and proximal regions was >20 mmHg. We performed EVT for the lesion, and the pFFR improved to 0.96. The systolic pressure gradient was only 1 mmHg at the lesion.

Discussion

Symptomatic PAD patients whose ABI or PSV on ultrasonography is insufficient for EVT could be diagnosed with ischaemia using a pressure gradient and pFFR.

Pressure- and Velocity-Based Physiological Assessment of Stenotic Lesions at Hyperemia in Superficial Femoral Artery Disease: Importance of Hyperemic Stenosis Resistance

Background: In superficial femoral artery (SFA) stenosis, stenosis resistance may increase, but the relationship between stenosis resistance and stenotic severity remains to be seen. This study aimed to investigate the physiological response, through a hyperemic condition, and the pathophysiological significance of Doppler flow and stenosis resistance in SFA. Methods: Twenty-four limbs with focal stenosis of the SFA were analyzed. We assessed the fractional flow reserve (FFR), hyperemic stenosis resistance (h-SR), and vascular flow reserve (VFR) of the SFA with a pressure/Doppler flow sensor-tipped combination guidewire before and after endovascular therapy (EVT). Results: FFR, h-SR, and VFR changed significantly after EVT. h-SR was more strongly correlated with % area stenosis, measured by intravascular ultrasound than FFR (FFR: r=-0.716, h-SR: r=0.741, p<0.0001, respectively). However, VFR was not associated with % area stenosis. A receiver operating characteristic curve showed cut-offs h-SR >0.36 mmHg·sec/cm, and FFR <0.88 predicted >75% area stenosis with area under curves of 0.883 and 0.828, respectively. Conclusion: h-SR can indicate stenotic severity in an SFA focal lesion more prominently than FFR and may be a new physiological index to determine indication for EVT. VFR was not feasible for assessment in SFA focal stenosis.

Comparative Outcomes After Percutaneous Coronary Intervention Among Black and White Patients Treated at US Veterans Affairs Hospitals

Importance

Current comparative outcomes among black and white patients treated with percutaneous coronary intervention (PCI) in the Veterans Affairs (VA) health system are not known.

Objective

To compare outcomes between black and white patients undergoing PCI in the VA health system.

Design, Setting, and Participants

This study compared black and white patients who underwent PCI between October 1, 2007, and September 30, 2013, at 63 VA hospitals using data recorded in the VA Clinical Assessment, Reporting, and Tracking System for Cardiac Catheterization Laboratories (CART-CL) program. A generalized linear mixed model with a random intercept for site assessed the relative difference in odds of outcomes between black and white patients. The setting was integrated institutionalized hospital care. Excluded were all patients of other races or those with multiple listed races and those with missing data regarding race or the diagnostic cardiac catheterization. The dates of analysis were January 7, 2016, to April 17, 2017.

Exposure

Percutaneous coronary intervention at a VA hospital.

Main Outcomes and Measures

The primary outcome was 1-year mortality. Secondary outcomes were 30-day all-cause readmission rates, 30-day acute kidney injury, 30-day blood transfusion, and 1-year readmission rates for myocardial infarction. In addition, variations in procedural and postprocedural care were examined, including the use of intravascular ultrasound, optical coherence tomography, fractional flow reserve measurements, bare-metal stents, postprocedural medications, and radial access.

Results

A total of 42 391 patients (13.3% black and 98.4% male; mean [SD] age, 65.2 [9.1] years) satisfied the inclusion and exclusion criteria. In unadjusted analyses, black patients had higher rates of 1-year mortality (7.1% vs 5.9%, P < .001) as well as secondary outcomes of 30-day acute kidney injury (20.8% vs 13.8%, P < .001), 30-day blood transfusion (3.4% vs 2.7%, P < .01), and 1-year readmission rates for myocardial infarction (3.3% vs 2.7%, P = .01) compared with white patients. After adjustment for demographics, comorbidities, and procedural characteristics, odds for 1-year mortality (odds ratio, 1.04; 95% CI, 0.90-1.19) were not different between black and white patients. There were also no differences in secondary outcomes with the exception of a higher rate of adjusted 30-day acute kidney injury (odds ratio, 1.22; 95% CI, 1.10-1.36).

Conclusions and Relevance

While black patients had a higher rate of mortality than white patients in unadjusted analyses, race was not independently associated with 1-year mortality among patients undergoing PCI in VA hospitals.

The Use of Fractional Flow Reserve for Physiological Assessment of Indeterminate Lesions in Peripheral Artery Disease

Peripheral artery disease (PAD) is a prevalent disorder in the United States, associated with significant morbidity and mortality. Fractional Flow Reserve (FFR) is a physiological test used to assess the hemodynamic significance of intermediate lesions on conventional angiography. It is well studied in coronary artery disease and is as an important tool to guide decisions regarding revascularization in a significant percentage of patients with intermediate lesions. As compared to coronary FFR, the use of FFR in peripheral artery disease (PFFR) is much less prevalent. Overall data regarding the use of the PFFR is sparse. There are limited studies that have shown the correlation of PFFR with non-invasive testing including ankle-brachial index (ABI) and Doppler Imaging. Unlike coronary FFR, the optimal pharmaceutical agents and doses to induce maximal hyperemia in the peripheral vascular bed are also not well established. Moreover, there are no established standardized procedural protocols for measuring PFFR. Various studies have employed varying techniques, hyperemic agents and doses. The aim of this literature review is to summarize the current evidence on PFFR, the correlation with noninvasive studies used in PAD and to increase awareness of the potential role of the PFFR in peripheral interventions.

Nitinol Self-Expanding Stents for the Superficial Femoral Artery

The superficial femoral artery is a complex artery subject to a unique set of biomechanical loading conditions in its course through the leg. Plain balloon angioplasty and balloon-expandable stents had unacceptably high rates of restenosis, necessitating target vessel revascularization. Nitinol alloy is well suited to provide the strength and flexibility needed of stents to withstand the external forces posed by the environment of the superficial femoral artery. Advances in stent technology with the addition of a slow-releasing antiproliferative agent and changes in scaffold design have shown promise in reducing the rates of stent fracture and in-stent restenosis.