Repeatability of fractional flow reserve despite variations in systemic and coronary hemodynamics

Objectives This study classified and quantified the variation in fractional flow reserve (FFR) due to fluctuations in systemic and coronary hemodynamics during intravenous adenosine infusion. Background Although FFR has become a key invasive tool to guide treatment, questions remain regarding its repeatability and stability during intravenous adenosine infusion because of systemic effects that can alter driving pressure and heart rate. Methods We reanalyzed data from the VERIFY (VERification of Instantaneous Wave-Free Ratio and Fractional Flow Reserve for the Assessment of Coronary Artery Stenosis Severity in EverydaY Practice) study, which enrolled consecutive patients who were infused with intravenous adenosine at 140 μg/kg/min and measured FFR twice. Raw phasic pressure tracings from the aorta (Pa) and distal coronary artery (Pd) were transformed into moving averages of Pd/Pa. Visual analysis grouped Pd/Pa curves into patterns of similar response. Quantitative analysis of the Pd/Pa curves identified the “smart minimum” FFR using a novel algorithm, which was compared with human core laboratory analysis. Results A total of 190 complete pairs came from 206 patients after exclusions. Visual analysis revealed 3 Pd/Pa patterns: “classic” (sigmoid) in 57%, “humped” (sigmoid with superimposed bumps of varying height) in 39%, and “unusual” (no pattern) in 4%. The Pd/Pa pattern repeated itself in 67% of patient pairs. Despite variability of Pd/Pa during the hyperemic period, the “smart minimum” FFR demonstrated excellent repeatability (bias −0.001, SD 0.018, paired p = 0.93, r2 = 98.2%, coefficient of variation = 2.5%). Our algorithm produced FFR values not significantly different from human core laboratory analysis (paired p = 0.43 vs. VERIFY; p = 0.34 vs. RESOLVE). Conclusions Intravenous adenosine produced 3 general patterns of Pd/Pa response, with associated variability in aortic and coronary pressure and heart rate during the hyperemic period. Nevertheless, FFR – when chosen appropriately – proved to be a highly reproducible value. Therefore, operators can confidently select the “smart minimum” FFR for patient care. Our results suggest that this selection process can be automated, yet comparable to human core laboratory analysis

Influence of orientation of bi-leaflet valve prostheses on coronary perfusion pressure in humans

Orientation of a bi-leaflet prosthesis (BLP) might influence coronary perfusion. The aim of this study was to investigate the influence of the orientation on coronary perfusion pressure during hyperemia and adrenergic stimulation. During hyperemia perfusion pressure determines coronary blood flow. Fourteen patients with normal coronary angiogram underwent aortic valve replacement (AVR) by a BLP, and seven received a bio-prosthesis. Patients receiving a BLP were randomized to either orientation A (hinge mechanism perpendicular to a line drawn between the coronary ostia) or B (hinge mechanism parallel to the line between the ostia). Six months after surgery all patients underwent cardiac catheterization. Pressures were measured during resting conditions, during maximum hyperemia, and during maximum adrenergic stimulation with a guiding catheter in the aortic arch (Pao), simultaneously with a sensor tipped guide wire in the coronary artery (Pcor) and in the aortic root (Proot). Pao-Proot described a flow-induced pressure drop in the aortic root (Venturi effect) and the gradient Proot-Pcor described coronary ostium abnormalities. Only small non-significant differences in myocardial perfusion pressure were found between different orientations of a bi-leaflet prosthesis or between bi-leaflet prostheses and bio-prostheses in Pao-Proot and Proot-Pcor

Evaluation of bifurcation stenting techniques at Catharina Hospital, Eindhoven in 2013

AimsPercutaneous coronary intervention (PCI) of bifurcation lesions can be performed using various techniques. The aim of this study was to analyse the outcome of various techniques of bifurcation stenting in all patients undergoing bifurcation stenting at one large intervention centre in 2013, taking into account that more complex lesions might more often warrant a two-stent technique.Methods and resultsThis retrospective study included 260 consecutive patients who underwent non-primary PCI of a bifurcation lesion at the Catharina Hospital, Eindhoven, in 2013. Patients were classified into two groups: one-stent technique (provisional stenting), and two-stent techniques (culotte, crush and T‑stenting). The primary endpoint was the rate of restenosis at 1 year. The secondary endpoints were procedural complications (side branch occlusion, periprocedural infarction, and death) and major adverse cardiac events (MACE) at 1 year. Periprocedural complications occurred in 15 patients (5.8 %) with no difference between the groups (p = 0.27). After 1 year, restenosis occurred in 3.2 % of the patients in the one-stent technique group and 7.3 % in the two-stent technique group (p = 0.20). MACE at 1 year did not differ between the groups at 11.9 % and 12.2 % respectively (p = 1.00).ConclusionsThis study shows that there is no significant difference between restenosis rate, or any other outcome parameter, with the different techniques of bifurcation stenting. Since provisional stenting is the simplest, most straightforward and cheapest approach, if technically feasible this technique has our preference as the initial approach, and an upgrade can be considered if the result is insufficient.KeywordsPercutaneous coronary interventionBifurcationStentingCulotteCrushProvisional stentingT-stentin

The relationship between fractional flow reserve, platelet reactivity and platelet leukocyte complexes in stable coronary artery disease

Background: The presence of stenoses that significantly impair blood flow and cause myocardial ischemia negatively affects prognosis of patients with stable coronary artery disease. Altered platelet reactivity has been associated with impaired prognosis of stable coronary artery disease. Platelets are activated and form complexes with leukocytes in response to microshear gradients caused by friction forces on the arterial wall or flow separation. We hypothesized that the presence of significantly flow-limiting stenoses is associated with altered platelet reactivity and formation of platelet-leukocyte complexes. Methods: One hundred patients with stable angina were studied. Hemodynamic significance of all coronary stenoses was assessed with Fractional Flow Reserve (FFR). Patients were classified FFR-positive (at least one lesion with FFR 0.80). Whole blood samples were stimulated with increasing concentrations of ADP, TRAP, CRP and Iloprost with substimulatory ADP. Expression of P-selectin as platelet activation marker and platelet-leukocyte complexes were measured by flowcytometry. Patients were stratified on clopidogrel use. FFR positive and negative patient groups were compared on platelet reactivity and platelet-leukocyte complexes. Results: Platelet reactivity between FFR-positive patients and FFR-negative patients did not differ. A significantly lower percentage of circulating platelet-neutrophil complexes in FFR-positive patients and a similar non-significant decrease in percentage of circulating platelet-monocyte complexes in FFR-positive patients was observed. Conclusion: The presence of hemodynamically significant coronary stenoses does not alter platelet reactivity but is associated with reduced platelet-neutrophil complexes in peripheral blood of patients with stable coronary artery disease

Treatment variation in stent choice in patients with stable or unstable coronary artery disease

Aim: Variations in treatment are the result of differences in demographic and clinical factors (e.g. anatomy), but physician and hospital factors may also contribute to treatment variation. The choice of treatment is considered important since it could lead to differences in long-term outcomes. This study explores the associations with stent choice: i.e. drug-eluting stent (DES) versus bare-metal stents (BMS) for Dutch patients diagnosed with stable or unstable coronary artery disease (CAD). Methods & results: Associations with treatment decisions were based on a prospective cohort of 692 patients with stable or unstable CAD. Of those patients, 442 patients were treated with BMS or DES. Multiple logistic regression analyses were performed to identify variables associated with stent choice. Bivariate analyses showed that NYHA class, number of diseased vessels, previous percutaneous coronary intervention, smoking, diabetes, and the treating hospital were associated with stent type. After correcting for other associations the treating hospital remained significantly associated with stent type in the stable CAD population. Conclusions: This study showed that several factors were associated with stent choice. While patients generally appear to receive the most optimal stent given their clinical characteristics, stent choice seems partially determined by the treating hospital, which may lead to differences in longterm outcome