Native Coronary Stenosis Research Articles

Propensity-matched lesion-based comparison of midterm outcomes of TAXUS Express and TAXUS Liberté stents for de novo native coronary stenosis

BackgroundWe examined the implication of the revised platform of TAXUS Liberté (TAXUS-Lib; Boston Scientific, Natick, MA, USA) from TAXUS Express (TAXUS-Exp; Boston Scientific) stents, after stent placements in a daily practice environment, on midterm clinical and angiographic outcomes. Methods and resultsBy adjusting historically different baselines with propensity score matching analysis in 1358 de novo native coronary stenoses, the incidence of the clinical safety endpoint (700-day cardiac death, nonfatal recurrent myocardial infarction, and definite stent thrombosis) after placement of TAXUS-Lib (0.60%; mean follow-up, 683±64 days) was not significantly different from that in the TAXUS-Exp group (1.20%; 677±96 days, p=0.182). Cardiac dysfunction (ejection fraction of left ventricle less than 40%) was the predictor of primary endpoint [odds ratio (OR), 17.8; 95% CI, 4.39–71.9; p<0.001]. In the baseline-adjusted angiographic followed-up lesions (n=443 in each arm), the incidence of secondary endpoint [binary in-stent restenosis: percent diameter stenosis (%DS) >50% at the follow-up angiography] in the TAXUS-Lib group (11.3%) was not significantly different from that in the TAXUS-Exp group (13.5%, p=0.368). TAXUS-Exp was not the predictor of secondary endpoint (OR, 1.20; 95% CI, 0.77–1.85; p=0.424). ConclusionsThe midterm clinical and angiographic outcomes after placement of the new TAXUS-Lib stent for de novo coronary stenosis in a daily practice environment were statistically equivalent compared to the former TAXUS-Exp.

Everolimus Versus Biolimus-eluting Stents: A Propensity Score Matching Analysis of 1.5-year Clinical and Angiographic Outcomes

The goal of this study was to compare the efficacy among second-generation drug-eluting stents (DES) (everolimus- (EES: Xience V / Promus) with biolimus- (BES: Nobori) eluting stents) for native coronary stenosis, because the direct comparison of the outcomes between those 2nd-generation DESs were not fully understood.

Retrospective Comparison of Midterm Clinical and Angiographic Outcomes after the Implantation of Paclitaxel- and Sirolimus-Eluting Stents for de novo Coronary Complex Lesions in Nonrandomized Japanese Patients

We retrospectively analyzed the midterm clinical and angiographic outcomes after the implantation of paclitaxel- (PES, TAXUS Express) and sirolimus- (SES, Cypher Bx Velocity) eluting stents in Japanese patients with complex coronary lesions. From August 2004 to May 2009, 1,335 nonrandomized de novo native complex coronary lesions treated with either a PES (357 cases) or SES were included. The inclusion criteria for patients with complex lesions were those with diabetes, those undergoing hemodialysis, and those with a low ejection fraction, as well as subjects who had lesions with severe calcification, ostiums of the right coronary and left circumflex arteries, and who underwent the side-branch bifurcation 2-stent technique. The subjects were evaluated for consistent predictors of cardiac events, binary restenosis and target lesion vascularization of the SES. The composite primary endpoint percentage (900-day cardiac death, nonfatal recurrent myocardial infarction, and definite stent thrombosis) after PES placement was 0.6%, which was not significantly different from that after SES placement (0.12%; p=0.290). The incidence of the secondary endpoint (binary restenosis; stenosis >50% of the diameter at the secondary angiographic examination performed within 550 days after the procedure) after PES placement (15.0%) was also not significantly different than that after SES placement (13.3%; p=0.498). There was no relationship between PES placement and binary restenosis upon angiographic follow-up of 989 lesions (odds ratio of 1.14; 95% confidence interval, 0.73-1.77; p=0.57). For de novo native complex coronary stenosis, the midterm safety and efficacy of PES placement was statistically equivalent to that of SES placement in a clinical setting in Japan.

A prospective randomised study using optical coherence tomography to assess endothelial coverage and neointimal proliferation at 6-months after implantation of a coronary everolimus-eluting stent compared with a bare metal stent postdilated with a paclitaxel-eluting balloon (OCTOPUS Trial): rationale, design and methods

Safety concerns regarding use of drug-eluting stent systems (DES) are related mostly to late stent thrombosis, which is facilitated by incomplete stent endothelial coverage. Specific information about time course and amount of endothelial strut coverage of different DES is required, in order to further refine the concept of antiplatelet therapy after DES implantation. Optical coherence tomography (OCT) is emerging as a new gold standard for endovascular imaging of stents, atherosclerosis progression, vulnerable plaque, and neointimal proliferation. The aim of this study is a comparative evaluation using OCT of the XIENCE V everolimus-eluting stent (Abbot Vascular, Santa Clara, CA, USA) on one hand, and the bare metal stent Coroflex Blue postdilated with the paclitaxel-eluting balloon Sequent Please (both from B Braun Melsungen AG, Melsungen, Germany) on the other hand, with respect to endothelial coverage and neointimal proliferation. Eighty patients scheduled for elective percutaneous coronary intervention (PCI) of a native coronary stenosis suitable for DES implantation and OCT imaging are scheduled to be openly randomised 1:1 to either XIENCE or Coroflex Blue/Sequent Please. The study is conducted prospectively at a university high-volume PCI centre with OCT expertise. Angiographic follow-up and time-domain OCT imaging with motorised pull-back at 1 mm/s are planned six months after study stent implantation in all patients. OCT endpoints are: (1) endothelial coverage, expressed as % of struts without coverage and % of stent length containing non-covered struts, and respectively (2) neointimal proliferation, given as % neointimal volumetric proliferation within the whole stent and also as peak focal % neointimal area proliferation. The study is not powered for clinical endpoints, which are: subacute or late stent thrombosis and need for revascularisation of the stent segment. Given the high number of measurements (15 cross-section images / 1 mm stent length), OCT endpoints are likely to reach significance at the level p <0.05, if the drop-out rate in follow-up does not exceed 20%. The study is currently on-going and its termination is scheduled for February 2010. (ClinicalTrials.gov identifier: NCT01056744).

Long-Term Patency Rate for Radial Artery vs. Saphenous Vein Grafts Using Same-Patient Materials

The aim of the present study was to assess the long-term graft patency rate of the radial artery (RA), in comparison to the saphenous vein (SV) in patients harvested for both vessels. RA and SV were concomitantly used for coronary artery bypass grafting in 318 patients in an 8-year period from January 2002 to March 2010. During follow-up, graft patency was assessed on angiography or multi-slice computed tomography in 192 of these patients. Cumulative graft patency rates were compared between RA and SV. Independent predictors for graft failure were examined for both vessels. Cumulative graft patency rates at 8 years were 74.3% in RA and 64.7% in SV, respectively. There was no significant difference between these types of grafts. Independent predictors of late RA graft failure were native coronary stenosis <75% and peripheral vascular disease (PVD). Independent predictors of late SV graft failure were use of only one anti-platelet agent and low-density lipoprotein cholesterol/high-density lipoprotein cholesterol ratio >2.5. Cardiovascular event-free and actuarial survival rates at 8 years in this series were 81.2% and 89.7%, respectively. Cumulative graft patency rates between RA and SV were similar at 8 years. RA performed more poorly in patients with target vessel stenosis <75% and in those complicated by PVD. Aggressive anti-platelet therapy and strict lipid control may be important in maintaining long-term patency of SV.

Determinants for successful sequential radial artery grafting to the left circumflex and right coronary arteries

The aim of this retrospective observational study was to delineate determinants for antegrade flow and entire patency of the sequential radial artery graft (RAG) in the left circumflex artery (LCX) and right coronary artery (RCA). Angiograms of 432 RAGs, which were sequentially anastomosed to the LCX and RCA, and were proximally anastomosed with the in-situ internal thoracic artery as the composite I- or Y-graft, were studied. The mean targets of RAG were 2.83±0.79. We examined effects of characteristics of RAG and the targets, such as native coronary stenosis and their combinations, on competitive flow and occlusion. Of 432 RAGs, 413 (95.6%) were patent to all targets, while 331 (76.6%) provided antegrade flow to all targets in sequential anastomoses. By the univariate and multivariate analyses, 51-75% stenosis of the most distal target was identified as the significant predictor of competitive flow or occlusion (OR=8.59, P<0.0001). The cumulative graft patency rate of RAGs with 76-100% stenosis of the most distal target at 40 months was 88.6%, whereas that of RAGs with 51-75% stenosis of the most distal target was 59.1% (P<0.0001). In sequential RAG, severity of stenosis in the most distal target had the significant impact on prevention of competitive flow and long-term patency to all targets.

Secondary Prevention, the Interventional Way

The pathophysiology of accelerated atherosclerosis in saphenous vein grafts (SVG) relates to progressive atheroma burden, neointimal hyperplasia, and vascular remodeling.1,2 Unfortunately, the therapeutic and clinical consequences of SVG disease are not trivial, and interventional cardiologists are wary of performing percutaneous coronary interventions (PCI) on degenerated SVG. Intervening on flow-limiting stenoses in SVG has long been associated with high complication rates;3 what was not well known to this date was the risk of stenting non–flow-limiting disease in SVG.4 Although techniques to mitigate distal embolization during SVG intervention have proliferated in the past decade, even optimal intervention with embolic protection devices, including proximal protection devices, filters, aspiration tools, and covered stents, have attendant higher complication rates than does native vessel PCI.5 Drug-eluting stents (DES) are of benefit in reducing restenosis compared with bare metal stents in SVG, but clinical adverse events are only marginally reduced, if at all.6–8 Article see p 1978 In this context, one may be perplexed by the report of Rodes-Cabau et al4 in this issue of Circulation , which proposes stenting non–flow-limiting stenoses in SVG with paclitaxel-eluting stents. Their study was founded on reasonable scientific grounds. Emboldened by the findings in native coronary stenoses that DES deployment in nonobstructive lesions resulted in relatively low rates of major adverse cardiac events and restenosis9 and the rapid progression of disease in degenerated SVG, these investigators hypothesized that in patients referred for symptom-driven coronary angiography, …

Feasibility, Safety, and Efficacy of a Novel Polymeric Pimecrolimus-Eluting Stent: Traditional Pre-Clinical Safety End Points Failed to Predict 6-Month Clinical Angiographic Results

The aim of this study was to determine the safety and efficacy of a novel pimecrolimus-eluting stent in a porcine coronary model and in a phase I clinical trial. Rapamycin- and paclitaxel-eluting stents reduce the need for repeat intervention by limiting neointimal hyperplasia but might cause delayed healing, pre-disposing patients to late stent thrombosis. Because inflammation plays a key role in restenosis, pimecrolimus, an anti-inflammatory drug, might reduce restenosis without adversely affecting re-endothelialization. We evaluated a novel polymeric pimecrolimus-eluting stent covered with a thin parylene C diffusion barrier in a porcine coronary model and in a phase I human clinical trial. The clinical study was a prospective, nonrandomized, first-in-human hypothesis-generating study that enrolled 15 patients who had a single de novo native coronary stenosis. At 28 days and 3 months in the porcine model, histopathologic indicators predicted safety and biocompatibility when stents coated with polymer only, drug only, and 2 drug-polymer formulations were compared with bare-metal stents (BMS). In the phase I clinical trial, 15 patients had successful implantation of pimecrolimus-eluting stents. By 6 months, no patient suffered death, myocardial infarction, or stent thrombosis. However, the angiographic restenosis (61%), mean late loss (1.44 mm), and repeat target lesion revascularization (53%) were significantly higher than historical BMS controls. Whereas the primary end point was percent volume obstruction, restenosis was so severe that operators performed intravascular ultrasound examination in only 6 patients. Pimecrolimus-eluting stents induced an exaggerated neointimal hyperplasia at 6 months in comparison with historical controls.

Remodeling of Reconstructed Left Anterior Descending Coronary Arteries With Internal Thoracic Artery Grafts

The internal thoracic artery (ITA) remodels its diameter in response to flow requirements. The objective of this study was to elucidate the remodeling capacity of the reconstructed coronary artery using the ITA. We evaluated coronary angiograms in 63 patients who had left anterior descending artery (LAD) segmental reconstruction with or without endarterectomy after off-pump coronary artery bypass graft surgery. The diameters of the ITA and reconstructed coronary artery were measured early and at 1 year after surgery. The mean diameter of the reconstructed LAD was significantly larger than that of the ITA, but significantly decreased 1 year after surgery (2.69 +/- 0.53 mm versus 1.87 +/- 0.39 mm; p > 0.0001). The proximal ratio, the ratio of the ITA to proximal reconstructed coronary artery, and the distal ratio, the ratio of the distal LAD to distal reconstructed coronary artery, increased to a value of almost 1.0 (0.77 +/- 0.11 versus 1.05 +/- 0.18, p < 0.0001, and 0.77 +/- 0.14 versus 0.92 +/- 0.12, p < 0.0001, respectively). Based on the mean diameter of the reconstructed coronary artery, there were no relationships between the use of endarterectomy and the degree of native coronary stenosis. The proximal ratio in the group with severe stenosis was significantly greater than that in the group with mild stenosis (1.08 +/- 0.18 versus 0.95 +/- 0.16; p = 0.036), although the distal ratio was not different between the two groups. Vascular remodeling of the coronary artery reconstructed with the ITA is observed within 1 year after surgery.

Causes of non-functioning right internal mammary used in a Y-graft configuration: insight from a 6-month systematic angiographic trial☆☆☆

Y-graft configuration with left and right ITA (RITA) allows complete arterial revascularisation. We previously compared two types of ITA revascularisation in a prospective randomised trial with a systematic 6-month angiographic follow-up study. The present study is a secondary analysis of these populations to evaluate the angiographic parameters influencing the function of the RITA used in a Y-graft configuration. The functionality of the RITA was based on the TIMI grade flow: in TIMI grade 0 (occluded graft) and in TIMI grade 1 or 2 (balanced flow), the RITA was considered not functional. RITA was considered functional when a complete opacification (TIMI 3) of all anastomoses of the targeted coronary vessels was observed. A total of 25.3% of RITA were not functional. In univariate analysis, the number of anastomoses, the type and size of grafted coronary segments and the severity of the native coronary stenosis influenced ITA function. In multivariate analysis, the function of the RITA was positively influenced by the number of anastomoses (OR=0.5, 95% CI: 0.4-0.7), and a severely narrowed first circumflex (OR=39.1, CI: 8.1-189.2) and negatively by the presence of a grafted intermediate coronary artery (OR=0.01, CI: 0.003-0.06), and of a grafted RCA (OR=0.08, CI: 0.02-0.35). The size of targeted vessel, history of infarction and regional myocardial function did not influence ITA function. In this systematic angiographic study, the function of the RITA used as a Y-graft was significantly improved when used on several branches of the circumflex artery or on a severely narrowed first circumflex. Grafting of the intermediate branch or of a RCA has a negative prognostic influence on graft function.

Patency rate of the internal thoracic artery to the left anterior descending artery bypass is reduced by competitive flow from the concomitant saphenous vein graft in the left coronary artery

In coronary artery bypass grafting (CABG), insufficient bypass flow can be a cause of occlusion or string sign of the internal thoracic artery (ITA) graft. A patent saphenous vein (SV) graft from the ascending aorta can reduce the blood flow through the ITA graft, and may affect its long-term patency. In the present study, we examined the impact of the patent SV graft to the left coronary artery on the long-term patency of the ITA to left anterior descending (LAD) artery bypass. We reviewed the coronary angiograms of 313 patients who had two bypasses to the left coronary artery including 1 in situ ITA to LAD graft between March 1986 and December 2006. Patients who had occlusion of either bypass grafts to the left coronary artery in the early angiography, were excluded. In 64 patients (20.4%), bilateral ITAs were individually anastomosed to the LAD and the second target branch in the left coronary artery (BITA group), while 249 patients (79.6%) had the ITA to LAD bypass and the SV graft to the second target branch in the left coronary artery (ITA/SV group). The mean follow-up period was 6.8+/-4.9 years. The cumulative patency rate of ITA-LAD bypasses at 10 years was 100% in the BITA group and 81.4% in the ITA/SV group. The ITA to LAD bypass was occluded in 14 (5.6%) patients of the ITA/SV group. In the ITA/SV group, the cumulative graft patency rate of the ITA to LAD bypass in patients who had severe (> or =76%) native coronary stenosis between the two anastomotic sites was 98.6% at 5 years, and was significantly higher than that of 82.3% in patients without severe stenosis (p<0.0001). Long-term patency of the ITA-LAD bypass was affected by the presence of the patent SV graft to the left coronary artery, particularly when the native coronary stenosis between the two anastomotic sites was not severe. Competitive flow from SV graft could play an important role in occlusion of the in-situ arterial graft.

Angiographic results of the radial artery graft patency according to the degree of native coronary stenosis☆

Radial arteries are gaining widespread acceptance as complementary arterial conduits for surgical myocardial revascularization, but there are limited reports about its angiographic patency compared with that of the internal thoracic artery or saphenous vein according to the degree of native coronary stenosis. Therefore, we tried to evaluate the mid-term angiographic results of the radial artery graft patency focusing on the native coronary stenotic status in a prospective manner. From March 2000 to September 2006, a total of 488 patients underwent coronary artery bypass grafting using radial artery graft at our institution. From this group, 123 patients (mean age of 59.02+/-8.9 years (range 34-73 years)) were enrolled in the present study, and underwent a postoperative angiography after surgery (mean 32 months). The angiograms were assessed visually and quantitatively. A total of 382 distal anastomoses were performed and 352 anastomosis remained patent (92.1%). Left internal thoracic artery showed the most excellent patency in all of the conduits (128/129, 99.2%). Overall the radial artery graft patency was 92% (160/174). In the univariate analysis, patency was significantly worse for targets of the right coronary system (left coronary system 129/135, 94.4% vs right coronary system 31/39, 79.4%. p<0.05) and the radial artery graft showed a higher patency rate in the case of a severe stenotic lesion that preoperatively revealed more than 90% stenosis (defined as critical stenotic lesion) than in the case of a less severe lesion (50%<stenosis<90%) (100/102, 98% vs 60/72, 83.3%. p<0.05). The methods used for proximal anastomosis failed to affect radial artery patency (p=0.123). Multivariate analysis revealed the target vessel stenotic degree (50%<stenosis<90%) was closely related to radial artery graft failure (p=0.002, Exp (B)=0.067, CI=0.012, -0.373). Regardless of the small study population, our data revealed that the radial artery conduit showed good midterm patency when it grafted to the critical stenotic lesion (over 90%). One might pay attention to the grafting strategy when the preoperative coronary angiogram reveals less than 90% of coronary stenosis, especially in the right coronary system but a larger and well-designed study should be warranted to confirm these findings.

Implantation of sirolimus-eluting stents in saphenous vein grafts is associated with high clinical follow-up event rates compared with treatment of native vessels

The clinical effectiveness of sirolimus-eluting stents (SES) for treatment of patients with saphenous vein graft disease is not well defined. This analysis sought to evaluate the clinical follow-up after treatment of stenotic saphenous vein grafts using SES in a large patient registry. Patients treated with SES for saphenous vein graft disease were compared with patients receiving SES in native vessel disease. This is a subanalysis from the prospective multicenter German Cypher Stent Registry. Only patients with completed 6 months clinical follow-up were included. The analysis comprises 344 patients with 353 lesions in saphenous vein grafts treated with 400 SES (Cypher, Cordis Inc., Cordis Corp., Warren, New Jersey, USA) and 6411 patients with 7607 native coronary artery lesions treated with 8725 SES. Mean SES length per lesion was 22.6+/-11.7 mm and mean stent diameter 3.0+/-0.3 mm in saphenous vein graft lesions. Target vessel revascularization rate was 18.1% and major adverse cardiovascular events (MACE) rate was 23.8% at 6-month follow-up after SES implantation for saphenous vein graft lesions. Even after adjustment for different baseline characteristics, target vessel failure and MACE rate were significantly higher after SES implantation for saphenous vein graft lesions than for native coronary vessel stenosis [odds ratio: 2.10 (95% confidence interval: 1.40-3.13), P<0.001] and [odds ratio: 2.15 (95% confidence interval: 1.49-3.09), P<0.001], respectively. Treatment of saphenous vein graft disease is associated with high target vessel revascularization and MACE rates also with the use of SES if applied to unselected patients. Target vessel revascularization and MACE rates remain significantly higher after SES for saphenous vein graft lesions than after SES in native vessel disease.

Angiographic flow grading and graft arrangement of arterial conduits

We sought to delineate the effects of competitive and reverse flow on the intermediate-term patency of arterial conduits and examined graft arrangements for maximizing antegrade bypass flow. The angiograms of 2083 bypass grafts in 570 patients who underwent off-pump total arterial revascularization without aortic manipulation since December 2000 were reviewed. The blood flow in the bypass grafts were graded A (antegrade), B (competitive), C (reverse), or O (occlusion). The mean number of distal anastomoses was 3.65 +/- 0.94 per patient. In the early angiography 91.3% (1901/2083) of the bypasses were grade A. Thirty (1.4%) bypasses were grade O, whereas 2.9% (61/2083) were grade B, and 4.4%(91/2083) were grade C. In the multivariate analysis the end-to-side anastomosis (P < .0001), 4 or more distal anastomoses of the conduit (P = .01), native coronary stenosis of less than 75% (P < .0001), and target branch location of the right coronary artery territory (P < .0001) and left circumflex artery territory (P = .02) significantly correlated with grade non-A. The patency rate in the late angiography of the bypasses graded B or C in the early angiography was 7 (28.0%) of 25, whereas that of the bypasses graded A was 164 (89.1%) of 184 (P < .0001). The actuarial graft patency rate of the bypasses graded A was 72.3% at 3 years and was significantly higher than that of the bypasses graded B or C (28.6% at 3 years after surgical intervention, P < .0001). The sufficient antegrade bypass flow had a favorable effect on the graft patency of arterial conduits. The graft arrangement should be adjusted for each patient so as to maximize the antegrade bypass flow and to confirm the advantage of arterial grafts.

Randomized trial of hormone therapy in women after coronary bypass surgery: Evidence of differential effect of hormone therapy on angiographic progression of disease in saphenous vein grafts and native coronary arteries

Clinical trials indicate that hormone therapy (HT) does not decrease cardiovascular disease events or angiographic coronary disease progression. The effects of HT on SVG vessels are unknown. To determine whether postmenopausal hormone therapy started after coronary bypass surgery (CABG) decreases saphenous vein graft (SVG) disease, we conducted a multicenter randomized placebo-controlled angiographic study of estradiol ± medroxyprogesterone started within 6 months of CABG in 83 postmenopausal women. Angiographic and intravascular ultrasound (IVUS) assessment at 6 and 42 months was planned to assess SVG disease progression. The study was stopped early following publication of the Women's Health Initiative Estrogen/Progestin study. Eighty-three subjects underwent a 6-month angiogram with 63 undergoing IVUS. Forty-five subjects completed the 42-month angiogram (20 underwent 42-month IVUS). In analysis of paired 6- and 42-month angiogram and IVUS studies, HT slowed angiographic progression of SVG disease assessed by mean percent stenosis ( p < 0.001), minimal lumen diameter ( p = 0.029), and total plaque volume ( p = 0.006). In contrast, HT accelerated disease progression in non-bypassed native coronary arteries (minimum lumen diameter, p = 0.01). SVG disease and closure occurred in 38% subjects within 1-year post-CABG. The groups had similar frequency of cardiovascular events expect for angioplasty that occurred in eight HT compared to one placebo subject ( p < 0.05). In HT subjects angioplasty was indicated for native coronary arterial stenoses while in the placebo subject angioplasty was indicated for SVG stenosis. This study suggests that hormone treatment may slow SVG disease progression while accelerating atherosclerosis in non-bypassed native coronary arteries.

Compliance of a cobalt chromium coronary stent alloy – the COVIS trial

BackgroundCobalt chromium coronary stents are increasingly being used in percutaneous coronary interventions. There are, however, no reliable data about the characteristics of unfolding and visibility of this stent alloy in vivo. The aim of this study is to compare cobalt chromium coronary stents with conventional stainless steel stents using intracoronary ultrasound.MethodsTwenty de novo native coronary stenoses ≤ 20 mm in length (target vessel reference diameter ≥ 2.5 and ≤ 4.0 mm) received under sequential intracoronary ultrasound either a cobalt chromium stent (Multi-Link Vision®; n = 10) or a stainless steel stent (Multi-Link Zeta®; n = 10).ResultsFor optimal unfolding, the cobalt chromium stent requires a higher balloon deployment pressure (13.90 ± 2.03 atm) than the stainless steel stent (11.50 ± 2.12 atm). Furthermore, the achieved target vessel diameter of the cobalt chromium stent (Visibility-Index QCA/IVUS Multi-Link Vision®1.13 / Multi-Link Zeta® 1.04) is more easily overrated by Quantitative Coronary Analysis.ConclusionThese data indicate that stent material-specific recommendations for optimal implantation pressure and different stent material with an equal design should both be considered in interpreting QCA-analysis.

Use of fractional flow reserve versus stress perfusion scintigraphy in stent restenosis

Background Fractional flow reserve (FFR) is a valid surrogate for hemodynamic significance in stenotic native coronary arteries. The aim of this study was to examine the value of FFR compared to stress perfusion myocardial scintigraphy (SPMS) in patients with coronary stent restenosis. Methods We studied 42 patients, aged 62 ± 10 years, with stent restenosis 5.3 ± 1.6 months after coronary stent implantation. All patients had a single coronary lesion of intermediate severity (diameter stenosis 40–70%). FFR measurement, SPMS, and quantitative angiography of the stent stenosis were performed in all patients. Results The mean percentage in stent diameter stenosis was 53 ± 9%. FFR was 0.77 ± 0.15. In 20 patients FFR was below 0.75. Nineteen patients had reversible perfusion defects in SPMS. FFR showed good diagnostic accuracy for the detection of reversible perfusion defects in SPMS (AUROC 0.86, 95% CI 0.74–0.98). The percentage of agreement of SPMS and FFR was 88%, with the best cutoff value of 0.75 for FFR. Conclusions A FFR value of 0.75 is not only valid for diagnosing significant native coronary stenosis, but also for stent restenosis. Thus, FFR measurement should be taken into account when making decisions regarding patients with stent restenosis.

Clinical Significance of Fractional Flow Reserve for Evaluation of Functional Lesion Severity in Stent Restenosis and Native Coronary Arteries

Fractional flow reserve (FFR) is a valid surrogate for hemodynamic significance in stenotic native coronary arteries, but its validity in patients with coronary stent restenosis is unknown. Prospective. University hospital. We studied 42 patients (mean age +/- 1 SD, 62 +/- 10 years) with stent restenosis and 57 patients (mean age, 61 +/- 12 years) with a native coronary lesion. All patients demonstrated a single coronary lesion of intermediate severity (stenosis diameter, 40 to 70%). Determination of FFR and quantitative angiography of the stenosis were performed. Stenosis diameter was comparable in both groups (native, 52 +/- 11%; stent, 52 +/- 9%; not significant [NS]). FFR was lower in stent restenosis (0.77 +/- 0.15 vs 0.82 +/- 0.12, p < 0.05) and more often pathologic with an FFR < 0.75 (48% vs 26%, p < 0.05) compared to native coronary stenosis. However, the area under the receiver operating characteristic curve for native stenosis was 0.82 (95% confidence interval [CI], 0.71 to 0.94) and for stent restenosis was 0.84 (95% CI, 0.71 to 0.97; NS). In patients with an FFR > 0.75, there was no adverse coronary event that was related to the stented lesion in the subsequent 6 months. The threshold of stenosis diameter of coronary lesions for pathologic FFR measurement (FFR < 0.75) is similar for stent restenosis and native coronary stenosis. Thus, FFR measurement seems to be applicable for decision making in patients with stent restenosis.

Pressure-derived measurement of coronary flow reserve

We aimed to validate the technique of measuring the coronary flow reserve (CFR) with coronary pressure measurements against an established thermodilution technique. The CFR has traditionally required measurement of coronary blood flow velocity with the Doppler wire and, more recently, using a thermodilution technique with the coronary pressure wire. However, recent work has suggested that the CFR may be derived from pressure measurements alone (the ratio of the square root of the pressure drop across an epicardial stenosis during hyperemia to that value at rest). This depends on the assumption that friction losses across a coronary stenosis are negligible. We compared pressure-derived CFR values with those obtained by the thermodilution technique using the intracoronary pressure wire in 38 stenoses in 34 patients with significant coronary stenoses undergoing percutaneous intervention. We also compared these two techniques of measuring CFR in 25 stenoses (6 vessels) artificially created by inflating small balloons within a stented coronary artery after percutaneous intervention. There is a close linear relationship between pressure-derived and thermodilution CFR in native (r(2) = 0.52; p < 0.001) and artificial stenoses (r(2) = 0.54; p < 0.05), although the pressure-derived technique appears to systematically underestimate CFR values in both situations. This applies to native and artificial stenoses. Coronary flow reserve cannot be measured merely with pressure alone, and it cannot be safely assumed that friction losses are negligible across a native coronary stenosis. These data suggest that friction loss is an important determinant of the pressure gradient along an atherosclerotic coronary artery.

Association between progression of untreated coronary lesions and in-stent restenosis

Progression of coronary artery disease is only incompletely understood regarding de-novo stenoses as well as in-stent restenoses (ISR) indicative of accelerated atherosclerosis. The objective of the present angiographic study was to prove an association between target lesion ISR and progression of primarily untreated coronary lesions. A total of 179 high-grade native coronary stenoses (mean diameter stenosis 68+/-16 %) of 131 patients were treated by stent implantation. Additional 101 lesions remained untreated because of their moderate to intermediate diameter stenoses (>30 %). Quantitative coronary angiographic analysis was performed 6+/-2 months later to evaluate ISR (diameter stenosis > 50 %), coronary progression (>20 % increase in diameter stenosis) and regression (>20 % decrease), respectively. Angiographic, procedural and clinical characteristics were assessed for a possible association with ISR and/or coronary progression and regression, respectively. ISR was seen in 70 of 179 (39 %) stented target lesions. Presence of diabetes mellitus (p = 0.04) and cumulative duration of inflations (p = 0.01) as procedural determinant were predictive for ISR. Significant progression was found in ten of 101 (10 %) primarily untreated lesions. Progression of previously normal segments or regression were not seen. Progression of native plaques was associated with ISR presence in nine cases and with ISR absence in only one case (p = 0.01). Of note, smoking (p = 0.02) turned out to be predictive for plaque progression, whereas medication and procedural/angiographic parameters were not. The findings of the present pilot study demonstrate target lesion ISR associated with progression of other primarily untreated lesions and thereby suggest that both atherosclerosis types share common systemic pathogenetic mechanisms. With presence of ISR, coronary angiography should also include primarily untreated arteries, especially in case of preexisting plaques.