Invasive fractional flow reserve: Which technology is best?

Invasive pressure measurements using hyperemic fractional flow reserve (FFR) and nonhyperemic pressure measurements (NHPR) are superior to angiography alone for assessment of 50-90% stenoses. FFR devices using piezoelectric and optical sensors achieve 94% concordance in FFR values; microcatheter designs have more lesion-crossing failures and less pressure drift compared with guidewire designs. Despite the similarity in statistical performance among FFR devices, interventional cardiologists may prefer to use NHPR to avoid the need for adenosine-related side effects, variations in vasodilator response, and limited application in patients with certain clinical and anatomic features.

Planning percutaneous coronary interventions using computed tomography angiography and fractional flow reserve-derived from computed tomography: A state-of-the-art review.

Fractional flow reserve derived by coronary computed tomography angiography (CTA; FFRCT) is an accurate noninvasive method for identifying coronary artery disease (CAD) and detecting hemodynamically significant stenosis. Although initially proposed as noninvasive tools to "rule out" significant CAD in low-risk patients, CTA and FFRCT are now utilized in higher-risk patients. Furthermore, new applications of CTA and FFRCT include a planning tool for percutaneous coronary intervention (PCI), which allows the cardiologist to assess lesion-specific ischemia, plan stent locations and sizes, and use virtual remodeling of the lumen (virtual stenting) to assess the functional impact of PCI. The purpose of this review is to discuss the principles of CTA and FFRCT acquisition, and their application for PCI planning, even before invasive angiography is performed.

Is optical coherence tomography a coherent strategy for carotid artery stenting?

Optical coherence tomography (OCT) is rarely necessary to guide clinical decisions about the appropriateness of carotid revascularization. For carotid artery stenting (CAS), computed tomography angiography is the best imaging tool to assess arch, carotid, and lesion-specific anatomy, including vessel dimensions and calcification. OCT is a coherent strategy after CAS to assess ambiguous angiographic findings and to guide appropriate therapy for dissection, thrombosis, and plaque prolapse.

Carotid stenting with double layered stents: Double trouble or double benefit?

The use of double layer (covered) stents during carotid artery stenting (CAS) appears to be safe; attenuation of plaque prolapse and distal embolization is reasonable but unproven. Double layer stents are commercially available in Europe but not in the United States; similar benefits might be obtained by implanting two self-expanding stents, to decrease the effective free cell area. Embolic protection devices (EPDs) are recommended in all CAS patients; the use of double layer stents does not eliminate the need for EPDs.

CO2 angiography: Colorless, odorless, but definitely not useless!

Contemporary approaches to minimize the risk of acute kidney injury from radiographic contrast (AKI-RC) rely on preferential use of low- or non-ionic contrast; pre-hydration; and limiting contrast volume. This study utilized a meta-analysis of 677 patients to compare the risk of AKI-RC after CO2 peripheral angiography versus iodinated contrast (4.3% vs. 11.1%, odds ratio [OR] 0.465, P = 0.048). There was no difference in AKI-RC in patients with CKD. This study has many limitations. CO2 angiography is an important technique; proper understanding of its strengths and limitations is essential.

Current approaches to retroperitoneal hemorrhage: Too little, too late.

Retroperitoneal hemorrhage (RPH) arises in < 0.5% of patients undergoing percutaneous intervention, but is associated with high risks of morbidity and mortality. More than 50% of medical malpractice claims against interventional cardiologists are related to death and hemorrhage from vascular injury; delays in diagnosis and treatment are common. The current approach to RPH is characterized by "too little" to diagnose and "too late" to manage patients in extremis. Immediate CTA allows rapid diagnosis and triage to appropriate endovascular therapy, without delay.

Improving outcomes after CABG and PCI.

Within 1 year of coronary artery bypass surgery , 64% of percutaneous coronary interventions were performed for graft failure and 36% for native vessel disease. Predictors of graft failure were small diameter of the graft and native vessel, poor distal run-off, and disease distal to the graft. In the near future, cardiac computed tomography angiography (CCTA) and fractional flow reserve by CT (FFRct) will incorporate accurate determination of coronary anatomy and the presence and extent of myocardial ischemia.

Invasive characterization of atherosclerotic plaque in patients with peripheral arterial disease using near-infrared spectroscopy intravascular ultrasound.

OBJECTIVES: We describe the characteristics of atherosclerotic plaque in patients with peripheral arterial disease (PAD) using near-infrared spectroscopy-intravascular ultrasound (NIRS-IVUS) BACKGROUND: Imaging and autopsy studies have described atherosclerotic plaque in different vascular beds, including varying degrees of lipid, fibrosis, and calcification. Recently, NIRS has been validated as an accurate method for detecting lipid-core plaque (LCP) in the coronary circulation. Invasive evaluation of plaque composition using NIRS-IVUS has not been reported in different peripheral arterial circulations. METHODS: We performed invasive angiography and NIRS-IVUS in consecutive PAD patients prior to percutaneous revascularization. Imaging evaluation included parameters from angiography, IVUS, and NIRS. NIRS-IVUS findings were compared among different vascular beds with regard to the presence and extent of calcification and LCP. RESULTS: One hundred and forty-nine lesions in 126 PAD patients were enrolled, including the internal carotid (n = 10), subclavian/axillary (n = 9), renal (n = 14), iliac (n = 35), femoropopliteal (n = 69), and infrapopliteal (n = 12) arteries. Plaque morphology was calcified in 132 lesions (89%) and fibrous in 17 lesions (11%). Calcification varied from 100% of renal artery stenoses to 55% of subclavian/axillary artery stenoses. LCP was present in 48 lesions (32%) and prevalence varied from 60% in carotid artery stenoses to 0% in renal artery stenoses (P < 0.005). LCP was only observed in fibrocalcific plaque, and was longitudinally and circumferentially surrounded by a more extensive degree of calcium. CONCLUSIONS: NIRS-IVUS in stable PAD patients demonstrates a high frequency of calcific plaque and statistically significant differences in the frequency of LCP in different arterial beds. LCP, when present in the peripheral circulation, is always associated with calcified plaque. The strong co-localization of calcified plaque and LCP in severe PAD lesions may provide plaque-stabilizing effects; further studies are needed. © 2017 Wiley Periodicals, Inc.

Saphenous vein bypass graft intervention and embolic protection devices: Time for reassessment (and revision of percutaneous coronary intervention guidelines).

Professional societies recommend embolic protection devices (EPDs) during percutaneous intervention of saphenous vein bypass grafts (SVGs; class I, level of evidence B). Practice patterns indicate that 21% of SVG interventions are performed with EPDs. Despite a single randomized trial that demonstrated efficacy for EPDs, other studies suggest that the benefits of EPDs are controversial. Consideration should be given toward performing a contemporary EPD trial to incorporate new technologies and pharmacotherapies; in the meantime, guideline recommendations for use of EPDs should be downgraded.

Women in interventional cardiology: Is there a problem?

In the United States, women account for 4% of interventional cardiologists and perform 3% of interventional procedures. Male and female cardiology fellows share concerns that dissuade them from careers in interventional cardiology; unique issues for women include professional isolation and childbearing. Interventional fellowships should enhance female mentorship and develop friendly policies regarding maternity leave; other issues require comprehensive solutions to medical school debt, duration of training, and balancing professional goals with lifestyle.

Double cerebral embolic protection: Is more less?

During carotid artery stenting (CAS), atheroemboli may arise from the aorta, arch, and ipsilateral carotid artery. Embolic protection devices (EPD) are designed to decrease the risk of stroke resulting from atheroembolization from the ipsilateral carotid artery during CAS; double (proximal and distal) EPDs may decrease the risk of stroke in high-risk patients and lesions. Further studies are needed to determine if double EPDs are superior to single EPDs or other devices.

Management of vascular access after TAVR: Let's keep it simple.

Bleeding and vascular complications are major causes of morbidity and mortality after transfemoral TAVR. Compared with standard approaches to hemostasis, the catheter balloon occlusion technique CBOT) resulted in significant reduction in major bleeding and vascular complications (18.6% vs. 5.5%, P = 0.042). Femoral crossover could not be achieved in 3.6%, and CBOT led to vessel dissection in 7.2%, major or life-threatening bleeding in 5.5%, need for transfusion > 2 units in 10.9%, and minor bleeding or hematoma in 21.8% of patients.

SCAI/SVM expert consensus statement on carotid stenting: Training and credentialing for carotid stenting.

Carotid artery stenting (CAS) has become an integral part of the therapeutic armamentarium offered by cardiovascular medicine programs for the prevention of stroke. The purpose of this expert consensus statement is to provide physician training and credentialing guidance to facilitate the safe and effective incorporation of CAS into clinical practice within these programs. Since publication of the 2005 Clinical Competence Statement on Carotid Stenting, there has been substantial device innovation, publication of numerous clinical trials and observational studies, accumulation of extensive real-world clinical experience and widespread participation in robust national quality improvement initiatives [5]. Collectively, these advances have led to substantial evolution in the selection of appropriate patients, as well as in the cognitive, technical and clinical skills required to perform safe and effective CAS. Herein, we summarize published guidelines, describe training pathways, outline elements of competency, offer strategies for tracking outcomes, specify facility, equipment and personnel requirements, and propose criteria for maintenance of CAS competency.

Invasive evaluation of plaque morphology of symptomatic superficial femoral artery stenoses using combined near-infrared spectroscopy and intravascular ultrasound.

The purpose of this study is to characterize the plaque morphology of severe stenoses in the superficial femoral artery (SFA) employing combined near-infrared spectroscopy and intravascular ultrasound (NIRS-IVUS). Atherosclerosis is the most common cause of symptomatic peripheral arterial disease. Plaque composition of SFA stenoses has been characterized as primarily fibrous or fibrocalcific by non-invasive and autopsy studies. NIRS has been validated to detect lipid-core plaque (LCP) in the coronary circulation. We imaged severe SFA stenoses with NIRS-IVUS prior to revascularization in 31 patients (46 stenoses) with Rutherford claudication ⩾ class 3. Angiographic parameters included lesion location and stenosis severity. IVUS parameters included plaque burden and presence of calcium. NIRS images were analyzed for LCP and maximum lipid-core burden index in a 4-mm length of artery (maxLCBI4mm). By angiography, 38 (82.6%) lesions were calcified and 9 (19.6%) were chronic total occlusions. Baseline stenosis severity and lesion length were 86.0 ± 11.0% and 36.5 ± 46.5 mm, respectively. NIRS-IVUS identified calcium in 45 (97.8%) lesions and LCP in 17 (37.0%) lesions. MaxLCBI4mm was 433 ± 244. All lesions with LCP also contained calcium; there were no non-calcified lesions with LCP. In conclusion, this is the first study of combined NIRS-IVUS in patients with PAD. NIRS-IVUS demonstrates that nearly all patients with symptomatic severe SFA disease have fibrocalcific plaque, and one-third of such lesions contain LCP. These findings contrast with those in patients with acute coronary syndromes, and may have implications regarding the pathophysiology of atherosclerosis in different vascular beds.

Carotid artery stenting: Optimizing patient selection and technique.

Complex arch anatomy (type 2, type 3) and bovine configuration were identified in 34.4% and 20.5% of carotid stent patients, respectively. Catheter manipulation time (CMT), rather than arch complexity per se, was the only independent predictor of adverse events after carotid stenting. Careful attention to patient selection, preprocedural planning, and stent technique are important to ensure success.

PCI of CTOs: hope or hype?

Compared with successful PCI, failed PCI of CTOs is associated with higher rates of in-hospital death, MI, CABG, perforation, and cardiac tamponade, but the absolute risk difference is small. Since 1991, the overall rates of in-hospital complications are declining, due to significant improvements in CTO technology and operator expertise. Outcomes after CTO-PCI may be enhanced by proper patient selection (resistant angina; large areas of ischemia; and anatomic suitability for antegrade, retrograde, and/or subintimal recanalization) and by reliance on expert operators using a flexible incremental approach to recanalization.

The role of jet eccentricity in generating disproportionately elevated transaortic pressure gradients in patients with aortic stenosis.

In patients with aortic stenosis (AS) and eccentric transaortic flow, greater pressure loss occurs as the jet collides with the aortic wall together with delayed and diminished pressure recovery. This leads to the elevated transaortic valve pressure gradients noted on both Doppler and cardiac catheterization. Such situations may present a diagnostic dilemma where traditional measures of stenosis severity indicate severe AS, while imaging modalities of the aortic valve geometric aortic valve area (GOA) suggest less than severe stenosis. In this study, we present a series of cases exemplifying this clinical dilemma and demonstrate how color M-mode, 2D and 3D transthoracic (TTE) and transesophageal (TEE) echocardiography, cardiac computed tomography angiography (CTA), and magnetic resonance imaging (MRI), may be used to resolve such discrepancies.

Diagnostic Performance of Diastolic Hyperemia-Free Ratio Compared With Invasive Fractional Flow Reserve for Evaluation of Coronary Artery Disease.

Hyperemic and nonhyperemic pressure ratios are frequently used to assess the hemodynamic significance of coronary artery disease and to guide the need for myocardial revascularization. However, there are limited data on the diagnostic performance of the diastolic hyperemia-free ratio (DFR). We evaluated the diagnostic performance of the DFR compared with invasive fractional flow reserve (FFR). We performed a prospective, single-center study of 308 patients (343 lesions) who underwent DFR and FFR for evaluation of visually estimated 40% to 90% stenoses. Diagnostic performance of the DFR compared with FFR was evaluated using linear regression, Bland-Altman analysis, and receiver operating characteristic curves. The overall diagnostic accuracy of the DFR was 83%; the accuracy rates were 86%, 40%, and 95% when the DFR was <0.86, 0.88 to 0.90, and >0.93, respectively. The sensitivity, specificity, positive predicative value, and negative predictive value were 60%, 91%, 71%, and 87%, respectively. The Pearson correlation coefficient was 0.75 (p <0.05). The Bland-Altman analysis showed a mean difference of 0.09, and the area under the receiver operating characteristic curve was 0.88 (95% confidence interval 0.84 to 0.92, p <0.05). In conclusion, the DFR has a good diagnostic performance compared with FFR but 17% of the measurements were discordant. The diagnostic accuracy of the DFR was only 40% when the DFR was 0.88 to 0.90, suggesting that FFR may be useful in these arteries.

Late Outcomes of Patients in the Emergency Department With Acute Chest Pain Evaluated With Computed Tomography-Derived Fractional Flow Reserve.

Computed tomography (CTA)-derived fractional flow reserve (FFRCT) guides the need for invasive coronary angiography (ICA). Late outcomes after FFRCT are reported in stable ischemic heart disease but not in acute chest pain in the emergency department (ACP-ED). The objectives are to assess the risk of death, myocardial infarction (MI), revascularization, and ICA after FFRCT. From 2015 to 2018, 389 low-risk patients with ACP-ED (negative biomarkers, no electrocardiographic ischemia) underwent CTA and FFRCT and were entered into a prospective institutional registry; patients were followed up for 41 ± 10 months. CTA stenosis ≥50% was present in 81% of the patients. Positive (FFRCT ≤0.80) and negative FFRCT were observed in 124 (32%) and 265 patients (68%), respectively. ICA was performed in 108 of 124 patients (87%) with positive FFRCT and 89 of 265 patients (34%) with negative FFRCT (p <0.00001). Revascularization was performed in 87 of 124 (70%) patients with positive FFRCT and in 22 of 265 (8%) with negative FFRCT (p <0.00001). Appropriateness of revascularization was established by blinded adjudication of ICA and invasive FFR using practice guidelines; revascularization was appropriate in 81 of 124 (65%) and 6 of 265 (2%) of FFRCT-positive and -negative patients, respectively (p <0.00001). At follow-up, for patients with positive versus negative FFRCT, the rates were 0.8% versus 0% for death (p = 0.32) and 1.6% versus 0.4% for MI (p = 0.24). In conclusion, in low-risk patients with ACP-ED who underwent CTA and FFRCT, the risk of late death (0.2%) and MI (0.7%) are low. Negative FFRCT is associated with excellent long-term prognosis, and positive FFRCT predicts obstructive disease requiring revascularization. FFRCT can safely triage patients with ACP-ED and reduce unnecessary ICA and revascularization.