Prediction of progression of coronary artery disease and clinical outcomes using vascular profiling of endothelial shear stress and arterial plaque characteristics: the PREDICTION Study

BACKGROUND

Atherosclerotic plaques progress in a highly individual manner. The purposes of the Prediction of Progression of Coronary Artery Disease and Clinical Outcome Using Vascular Profiling of Shear Stress and Wall Morphology (PREDICTION) Study were to determine the role of local hemodynamic and vascular characteristics in coronary plaque progression and to relate plaque changes to clinical events.

METHODS AND RESULTS

Vascular profiling, using coronary angiography and intravascular ultrasound, was used to reconstruct each artery and calculate endothelial shear stress and plaque/remodeling characteristics in vivo. Three-vessel vascular profiling (2.7 arteries per patient) was performed at baseline in 506 patients with an acute coronary syndrome treated with a percutaneous coronary intervention and in a subset of 374 (74%) consecutive patients 6 to 10 months later to assess plaque natural history. Each reconstructed artery was divided into sequential 3-mm segments for serial analysis. One-year clinical follow-up was completed in 99.2%. Symptomatic clinical events were infrequent: only 1 (0.2%) cardiac death; 4 (0.8%) patients with new acute coronary syndrome in nonstented segments; and 15 (3.0%) patients hospitalized for stable angina. Increase in plaque area (primary end point) was predicted by baseline large plaque burden; decrease in lumen area (secondary end point) was independently predicted by baseline large plaque burden and low endothelial shear stress. Large plaque size and low endothelial shear stress independently predicted the exploratory end points of increased plaque burden and worsening of clinically relevant luminal obstructions treated with a percutaneous coronary intervention at follow-up. The combination of independent baseline predictors had a 41% positive and 92% negative predictive value to predict progression of an obstruction treated with a percutaneous coronary intervention.

CONCLUSIONS

Large plaque burden and low local endothelial shear stress provide independent and additive prediction to identify plaques that develop progressive enlargement and lumen narrowing.

CLINICAL TRIAL REGISTRATION

URL: http:www.//clinicaltrials.gov. Unique Identifier: NCT01316159.

Novel methodology for 3D reconstruction of carotid arteries and plaque characterization based upon magnetic resonance imaging carotid angiography data

In this study, we present a novel methodology that allows reliable segmentation of the magnetic resonance images (MRIs) for accurate fully automated three-dimensional (3D) reconstruction of the carotid arteries and semiautomated characterization of plaque type. Our approach uses active contours to detect the luminal borders in the time-of-flight images and the outer vessel wall borders in the T(1)-weighted images. The methodology incorporates the connecting components theory for the automated identification of the bifurcation region and a knowledge-based algorithm for the accurate characterization of the plaque components. The proposed segmentation method was validated in randomly selected MRI frames analyzed offline by two expert observers. The interobserver variability of the method for the lumen and outer vessel wall was -1.60%±6.70% and 0.56%±6.28%, respectively, while the Williams Index for all metrics was close to unity. The methodology implemented to identify the composition of the plaque was also validated in 591 images acquired from 24 patients. The obtained Cohen's k was 0.68 (0.60-0.76) for lipid plaques, while the time needed to process an MRI sequence for 3D reconstruction was only 30 s. The obtained results indicate that the proposed methodology allows reliable and automated detection of the luminal and vessel wall borders and fast and accurate characterization of plaque type in carotid MRI sequences. These features render the currently presented methodology a useful tool in the clinical and research arena.

Abstract 347: Early Drug-Induced Inhibition of Proatherogenic Genes in Coronary Regions of Low Endothelial Shear Stress in Diabetic Hyperlipidemic Juvenile Swine

Introduction: Low endothelial shear stress (ESS) activates pro-inflammatory pathways and is a powerful instigator of atherogenesis. Angiotensin receptor blockers and statins have been associated with anti-inflammatory actions in advanced plaques. However, their effect on the earliest pathobiologic manifestations of atherosclerosis has not been studied. We tested the hypothesis that valsartan (V) or V plus simvastatin (V/S) exerts an early vasculoprotective effect in coronary regions exposed to low ESS in a porcine model of human-like atherosclerosis.

Methods: Twelve diabetic-hyperlipidemic swine (age: 3 mo) were grouped into controls (n=4), and those treated with V (320 mg; n=4) or V/S (320/40 mg; n=4). 3D reconstruction of coronary arteries by angiography and intravascular ultrasound was performed in vivo at 4 (baseline) and 8 (follow-up) wks post-induction. Baseline local ESS was calculated by computational fluid dynamics and 3 mm segments with low (≤1.2 Pa; n=46) or higher (>1.2 Pa; n=66) ESS were identified. Coronary arteries were harvested at follow-up. qRT-PCR was used for assessing the expression of intercellular adhesion molecule-1 (ICAM-1), monocyte chemoattractant protein-1 (MCP-1), LDL receptor and lipoprotein-associated phospholipase-A 2 (LpPLA 2 ).

Results: The upregulation of ICAM-1, MCP-1, LDL receptor (p<0.05) and LpPLA 2 (p<0.1) expression in low ESS segments was inhibited in the V and V/S groups compared to controls (Figure).

Conclusion: V and V/S attenuate the proatherogenic effects of low ESS within only 8 wks. These results suggest a drug-induced mechanism of regional atheroprotection early in the natural history of coronary artery disease.

Abstract 515: Increased Adventitial Inflammation Occurs in Regions of Low Endothelial Shear Stress in a Swine Model of Coronary Atherosclerosis

Introduction: Plaque inflammation is a critical step in the initiation and progression of atherosclerosis. Such inflammation is thought to originate from the luminal surface of plaque and infiltrate the intima-media in advanced lesions. Low endothelial shear stress (ESS) is known to induce intima-media inflammation and plaque growth. In this study we investigated in-vivo the hypothesis that low ESS induces also adventitial inflammation.

Methods: We studied 11 swine at 23 (baseline) and 30 (followup) weeks after the induction of diabetes and hyperlipidemia. Using angiography and intravascular ultrasound data, we performed 3D coronary reconstruction of coronary arteries and calculated the ESS with computational fluid dynamics. In 56 segments, we assessed the adventitial inflammatory (CD45) and antigen-presenting (MHC-II) cell content at followup with immunohistochemistry. Segments were classified as low (≤ 1 Pa) or higher (>1 Pa) ESS.

Results: MHC-II content in the adventitia (1.3±0.3%) was higher than in the media (0.3±0.1%, p<0.001) but lower than in the intima (9.3±2.3%, p<0.001). Low-ESS regions had increased adventitial MHC-II content compared to high-ESS regions (1.6±0.4 vs. 0.9±0.3%, p<0.05). Adventitial MHC-II content was not influenced by plaque size (large plaques 1.7±0.5 vs. intermediate plaques 0.8±0.3%, p=0.24), internal elastic lamina fragmentation (IEL) grade (minimal/absent 0.6±0.3 vs. moderate/large 1.4±0.3, p=0.9), or remodeling pattern (inadequate 1.7±0.6 vs. compensatory 1.2±0.4 vs. expansive 0.6±0.2%, p=0.6). Adventitial CD45 content was not significantly different between low- and high-ESS segments, and also not different in large vs. intermediate plaques, in segments with various IEL fragmentation grades or remodeling patterns.

Conclusion: Although total inflammation is not dependent on ESS, low ESS induces higher adventitial activated inflammatory cell content, as assessed by MHC-II immunostaining. This, in conjunction with the higher MHC-II content in the adventitia than in the media and the presence of an intact IEL suggests an additional source of inflammation in low-ESS plaque regions, originating from the vessel outer wall. The induction of neovascularization possibly accounts for this phenomenon.

Drug-eluting stent restenosis: effect of drug type, release kinetics, hemodynamics and coating strategy

Restenosis following stent implantation diminishes the procedure's efficacy influencing long-term clinical outcomes. Stent-based drug delivery emerged a decade ago as an effective means of reducing neointimal hyperplasia by providing localized pharmacotherapy during the acute phase of the stent-induced injury and the ensuing pathobiological mechanisms. However, drug-eluting stent (DES) restenosis may still occur especially when stents are used in complex anatomical and clinical scenarios. A DES consists of an intravascular metallic frame and carriers which allow controlled release of active pharmaceutical agents; all these components are critical in determining drug distribution locally and thus anti-restenotic efficacy. Furthermore, dynamic flow phenomena characterizing the vascular environment, and shear stress distribution, are greatly influenced by stent implantation and play a significant role in drug deposition and bioavailability within local vascular tissue. In this review, we discuss the performance of DES and the interaction of the different DES components with the hemodynamic milieu emphasizing on the inhibition of clinical restenosis.

The effect of statins on high-risk atherosclerotic plaque associated with low endothelial shear stress

PURPOSE OF REVIEW

Low endothelial shear stress (ESS) plays an important role in the progression and severity of atherosclerotic lesions. As 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) appear to stabilize plaque, it would be valuable to understand how statins affect the nature of lesions in the proatherogenic and proinflammatory environment of low ESS and the effect of statins on that atherosclerotic process. The purpose of this review is to summarize the relationship among low ESS, high-risk plaque and statins.

RECENT FINDINGS

Low ESS is a critically important determinant of plaque development and progression to high-risk plaques with large necrotic lipid core, intensive inflammation and thin fibrous cap. In addition to the proatherogenic phenotypic switching in areas of low ESS, local LDL cholesterol concentrations are also increased in areas of low ESS, which exacerbates the local atherogenic process. In experimental models, statins appear to reduce the inflammation in lesions associated with low ESS and reduce the atherosclerotic phenotype even in these high-risk prone vascular areas.

SUMMARY

The relationship between low ESS and statins has not been fully investigated, but the available data underscore the vasculoprotective effect of statins. Understanding the mechanisms whereby statins reduce the atherogenic and inflammatory phenotype resulting from a low ESS environment would provide new insights to design strategies to prevent regional formation of high-risk, inflamed plaques likely to rupture and cause an adverse clinical event.

Rosiglitazone improves endothelial function in patients with type 2 diabetes treated with insulin

An increased incidence of myocardial infarction with rosiglitazone in patients with type 2 diabetes mellitus (T2DM) has been reported. This study aimed to assess the effect of rosiglitazone on endothelial function, assessed by flow-mediated dilation (FMD), in 34 patients with advanced T2DM treated with insulin without known cardiovascular disease. Patients were randomised into two groups: no additional treatment was given in 17 patients, while 17 patients were given rosiglitazone for 6 months. Addition of rosiglitazone significantly reduced glycosylated haemoglobin (HbA(1c)) (p < 0.0005) and fasting glucose (p < 0.05) and improved FMD (p < 0.005). No significant changes were observed in the insulin-only group. The single independent predictor of FMD improvement was rosiglitazone treatment (p = 0.048). These results show that, in patients with advanced T2DM treated with insulin, addition of rosiglitazone may have a beneficial effect on endothelial function. Further research is needed to investigate why this beneficial effect does not translate into improved cardiovascular prognosis in these patients.

The effect of shear stress on neointimal response following sirolimus- and paclitaxel-eluting stent implantation compared with bare-metal stents in humans

OBJECTIVES

We aimed to explore the relationship of neointimal thickness (NT) to shear stress (SS) after implantation of sirolimus-eluting stents (SES) and paclitaxel-eluting stents (PES) compared with bare-metal stents (BMS). We then tested the hypothesis that drug elution attenuates the SS effect.

BACKGROUND

Neointimal thickness after BMS implantation has been associated with SS; pertinent data for drug-eluting stents (DES) are limited.

METHODS

Three-dimensional coronary artery and stent reconstruction was performed in 30 patients at 6-month follow-up after SES (n = 10), PES (n = 10), or BMS (n = 10) implantation. Baseline SS at the stent surface was calculated using computational fluid dynamics and NT at follow-up was computed in 3-dimensional space.

RESULTS

Neointimal thickness was lower in DES versus BMS (0.03 ± 0.07 mm vs. 0.16 ± 0.08 mm, p < 0.001) and maximum NT was reduced in SES versus PES (0.33 ± 0.13 mm vs. 0.46 ± 0.13 mm, p = 0.025). In the total population, both SS (slope: -0.05 mm/Pa, p < 0.001) and DES (coefficient for DES vs. BMS: -0.17 mm, p = 0.003) were independent predictors of NT. Subgroup analysis demonstrated a significant negative relationship of NT to SS in PES (slope: -0.05 mm/Pa, p = 0.016) and BMS (slope: -0.05 mm/Pa, p = 0.001). Sirolimus elution significantly attenuated the effect of SS on NT (interaction coefficient for SES vs. BMS: 0.04 mm/Pa, p = 0.023), whereas the SS effect remained unchanged in PES (interaction coefficient for PES vs. BMS: 0.01 mm/Pa, p = 0.71).

CONCLUSIONS

Neointimal thickness is significantly correlated (inversely) to SS in PES as in BMS. Sirolimus elution abrogates the SS effect on the neointimal response following stent implantation, whereas the SS effect is unchanged in PES.

Augmented expression and activity of extracellular matrix-degrading enzymes in regions of low endothelial shear stress colocalize with coronary atheromata with thin fibrous caps in pigs

Background- The molecular mechanisms that determine the localized formation of thin-capped atheromata in the coronary arteries remain unknown. This study tested the hypothesis that low endothelial shear stress augments the expression of matrix-degrading proteases and thereby promotes the formation of thin-capped atheromata. Methods and Results- Intravascular ultrasound-based, geometrically correct 3-dimensional reconstruction of the coronary arteries of 12 swine was performed in vivo 23 weeks after initiation of diabetes mellitus and a hyperlipidemic diet. Local endothelial shear stress was calculated in plaque-free subsegments of interest (n=142) with computational fluid dynamics. At week 30, the coronary arteries (n=31) were harvested and the same subsegments were identified. The messenger RNA and protein expression and elastolytic activity of selected elastases and their endogenous inhibitors were assessed. Subsegments with low preceding endothelial shear stress at week 23 showed reduced endothelial coverage, enhanced lipid accumulation, and intense infiltration of activated inflammatory cells at week 30. These lesions showed increased expression of messenger RNAs encoding matrix metalloproteinase-2, -9, and -12, and cathepsins K and S relative to their endogenous inhibitors and increased elastolytic activity. Expression of these enzymes correlated positively with the severity of internal elastic lamina fragmentation. Thin-capped atheromata developed in regions with lower preceding endothelial shear stress and had reduced endothelial coverage, intense lipid and inflammatory cell accumulation, enhanced messenger RNA expression and elastolytic activity of MMPs and cathepsins, and severe internal elastic lamina fragmentation. Conclusions- Low endothelial shear stress induces endothelial discontinuity and accumulation of activated inflammatory cells, thereby augmenting the expression and activity of elastases in the intima and shifting the balance with their inhibitors toward matrix breakdown. Our results provide new insight into the mechanisms of regional formation of plaques with thin fibrous caps.

Eight-year clinical outcome after radioactive stent implantation: a treatment failure without irreversible long-term clinical sequelae

AIMS

To assess the long-term outcome of patients who underwent radioactive stent (RS) implantation.

METHODS AND RESULTS

The RS study population consisted of 133 consecutive patients who underwent RS implantation between November 1997 and July 2000. They were matched using the propensity score method with 266 patients who underwent bare metal stenting (BMS) in the same span. Long-term survival status and information on MACE (death, non-fatal myocardial infarction or any re-intervention) was retrospectively obtained. Eight-year cumulative survival (90.2% vs. 87.4%, p = 0.57) was similar between the RS and BMS group respectively, while 8-year cumulative MACE-free survival was significantly lower in RS patients (42.1% vs. 64.3%, p < 0.001) due to the difference in events (mainly target lesion revascularisations [TLRs]) during the first year of follow-up (cumulative 1-year MACE-free survival: 59.4% vs. 86.7%, p < 0.001); there was no difference in the MACE rate after the first year (p = 0.71). The TLR rate at six months in the RS group was 29.3%, mainly due to edge restenosis and at one year 36.2% (control group: 9.5%, p < 0.001).

CONCLUSIONS

A high incidence of MACE and re-intervention was observed during the first year following RS implantation, mainly related to TLR for edge restenosis. After the first year, the clinical outcome of RS patients was similar to the control group indicating that there are no late adverse effects related to low dose-rate intracoronary radiation therapy.

Septal wire entrapment during recanalisation of a chronic total occlusion with the retrograde approach

We report the case of an unsuccessful attempt at recanalisation of a chronic total occlusion via the retrograde approach, and describe a rare complication, guide wire entrapment in the donor artery and septal branch. Several conventional attempts to retrieve the guide wire were unsuccessful and led to wire fracture. A new approach, involving very deep guiding catheter intubation followed by a double guide wire rotary motion, was then used to retrieve the proximal end of the wire fragment and re-engage the uncoiled segment within the distal part of the donor artery. After assessment of the length of the remaining distal end of the wire segment with intravascular ultrasound, stent implantation crushed the wire filament to the vessel wall.

Angiographic thrombus burden classification in patients with ST-segment elevation myocardial infarction treated with percutaneous coronary intervention

The presence of thrombus is associated with adverse clinical outcomes. Our aim was to develop a classification of thrombus burden (TB) in patients with ST-segment elevation myocardial infarction (STEMI).

METHODS

We retrospectively analyzed 900 consecutive patients treated with percutaneous coronary intervention for STEMI. Drug-eluting stents were used in 90.1%. TB was graded (G) as G0 = no thrombus, G1 = possible thrombus, G2 = small [greatest dimension ≤ 1/2 vessel diameter (VD)], G3 = moderate (> 1/2 but < 2VD), G4 = large (≥ 2VD), G5 = unable to assess TB due to vessel occlusion. Patients with G5 were reclassified to a thrombus category after flow achievement either with a guidewire or a small (1.5 mm) balloon. The incidence of major adverse cardiac events (MACE) - defined as death, myocardial infarction and infarct-related artery revascularization - was computed using the Kaplan-Meier method.

RESULTS

Median duration of follow-up was 18.5 months. G5 patients constituted 57.7% of all patients and reclassification was achieved in 97.9%. TB after reclassification was G0, 8.1%; G1, 19%; G2, 24.5%, G3,16.6%, G4, 30%, G5, 1.9%. The 2-year cumulative MACE-free survival was comparable in G1, G2, G3 (84.5%, 85.9% and 87% respectively, p = 0.83), while G0 (75.8%) and G4 (75%) did significantly worse (p = 0.001). After stratification in two groups of small (G0-3) and large (G4) TB, the latter was found to be an independent predictor for 2-year mortality (HR: 1.66, 95% CI: 1.04-2.68, p = 0.035) and MACE rate (HR: 2.04, 95% CI: 1.44-2.88, p < 0.001).

CONCLUSIONS

In patients with STEMI, TB can be reliably estimated in occluded infarct-related arteries. Large thrombus (≥ 2 VD) is a significant independent predictor for mortality and MACE.

Natural history of experimental coronary atherosclerosis and vascular remodeling in relation to endothelial shear stress: a serial, in vivo intravascular ultrasound study

BACKGROUND

The natural history of heterogeneous atherosclerotic plaques and the role of local hemodynamic factors throughout their development are unknown. We performed a serial study to assess the role of endothelial shear stress (ESS) and vascular remodeling in the natural history of coronary atherosclerosis.

METHODS AND RESULTS

Intravascular ultrasound-based 3-dimensional reconstruction of all major coronary arteries (n=15) was performed serially in vivo in 5 swine 4, 11, 16, 23, and 36 weeks after induction of diabetes mellitus and hyperlipidemia. The reconstructed arteries were divided into 3-mm-long segments (n=304). ESS was calculated in all segments at all time points through the use of computational fluid dynamics. Vascular remodeling was assessed at each time point in all segments containing significant plaque, defined as maximal intima-media thickness >/=0.5 mm, at week 36 (n=220). Plaque started to develop at week 11 and progressively advanced toward heterogeneous, multifocal lesions at all subsequent time points. Low ESS promoted the initiation and subsequent progression of plaques. The local remodeling response changed substantially over time and determined future plaque evolution. Excessive expansive remodeling developed in regions of very low ESS, further exacerbated the low ESS, and was associated with the most marked plaque progression. The combined assessment of ESS, remodeling, and plaque severity enabled the early identification of plaques that evolved to high-risk lesions at week 36.

CONCLUSIONS

The synergistic effect of local ESS and the remodeling response to plaque formation determine the natural history of individual lesions. Combined in vivo assessment of ESS and remodeling may predict the focal formation of high-risk coronary plaque.

Comparison of Quantitative Coronary Angiography with Intracoronary Ultrasound. Can Quantitative Coronary Angiography Accurately Estimate the Severity of a Luminal Stenosis?

In this study we investigated the accuracy of monoplane and biplane quantitative coronary angiography in estimating the luminal dimensions, using intracoronary ultrasound as gold standard. Biplane angiography and intracoronary ultrasound were performed in 24 arterial segments. The end-diastolic intracoronary ultrasound frames were manually selected and segmented. In 2 end-diastolic X ray projections, quantitative coronary angiography was performed and a novel methodology was applied to register the segmented frames onto the processed angiographic images. The luminal areas determined by quantitative coronary angiography in 1 (monoplane) and 2 projections (mean) were compared with those determined by intracoronary ultrasound. The obtained correlation coefficients for the monoplane and mean estimations were 0.69 ±0.12 and 0.77 ± 0.08 respectively. It would appear that by increasing the angle between the biplane projections, the correlation between intracoronary ultrasound and mean estimations improves. Our results provide evidence that orthogonal biplane angiography is more reliable and should be preferred to assess luminal dimensions.

Angiographic stent thrombosis after routine use of drug-eluting stents in ST-segment elevation myocardial infarction: the importance of thrombus burden

OBJECTIVES

This study sought to investigate the impact of thrombus burden on the clinical outcome and angiographic infarct-related artery stent thrombosis (IRA-ST) in patients routinely treated with drug-eluting stent (DES) implantation for ST-segment elevation myocardial infarction (STEMI).

BACKGROUND

There are limited data for the safety and effectiveness of DES in STEMI.

METHODS

We retrospectively analyzed 812 consecutive patients treated with DES implantation for STEMI. Intracoronary thrombus burden was angiographically estimated and categorized as large thrombus burden (LTB), defined as thrombus burden > or =2 vessel diameters, and small thrombus burden (STB) to predict clinical outcomes. Major adverse cardiac events (MACE) were defined as death, repeat myocardial infarction, and IRA reintervention.

RESULTS

Mean duration of follow-up was 18.2 +/- 7.8 months. Large thrombus burden was an independent predictor of mortality (hazard ratio [HR] 1.76, p = 0.023) and MACE (HR 1.88, p = 0.001). The cumulative angiographic IRA-ST was 1.1% at 30 days and 3.2% at 2 years, and continued to augment beyond 2 years. It was significantly higher in the LTB compared with the STB group (8.2% vs. 1.3% at 2 years, respectively, p < 0.001). Significant independent predictors for IRA-ST were LTB (HR 8.73, p < 0.001), stent thrombosis at presentation (HR 6.24, p = 0.001), bifurcation stenting (HR 4.06, p = 0.002), age (HR 0.55, p = 0.003), and rheolytic thrombectomy (HR 0.11, p = 0.03).

CONCLUSIONS

Large thrombus burden is an independent predictor of MACE and IRA-ST in patients treated with DES for STEMI.

Coronary dilatation 10 weeks after paclitaxel-eluting stent implantation. No role of shear stress in lumen enlargement?

We report a patient with coronary dilatation 10 weeks after paclitaxel-eluting stent implantation in the right coronary artery (RCA). Coronary angiography demonstrated a double-locular lumen dilatation in the body of the stented segment of the RCA, and intravascular ultrasound interrogation revealed the corresponding region with evidence of tissue regression behind the stent struts, incomplete stent apposition, and lumen enlargement. After three-dimensionally (3D) reconstructing the RCA, we applied computational fluid dynamics to the 3D RCA model, representing the lumen of the artery at the moment of stent implantation, and investigated the correlation of both neointimal thickness and tissue regression depth with shear stress in the stent. Neointimal thickness was found to be inversely related to shear stress, but there was no significant association of tissue regression depth with shear stress. Post-procedural stent malapposition, thrombus dissolution, and less possibly, a localized hypersensitivity reaction are potential mechanisms for the lumen enlargement in this case.

The impact of renal function on the long-term clinical course of patients who underwent percutaneous coronary intervention

OBJECTIVES

To determine the impact of the level of kidney function on the extended (>5 years) long-term clinical course of patients undergoing percutaneous coronary intervention (PCI).

BACKGROUND

Chronic kidney disease (CKD) has been significantly associated with an increased in-hospital and 1-year mortality following PCI.

METHODS

In this single-centre retrospective study, glomerular filtration rate (GFR) at baseline was estimated in 371 patients not on dialysis, who underwent successful PCI between mid-1995 and mid-1999. Baseline demographic and angiographic characteristics, and long-term major adverse cardiac events and symptoms were compared for patients with GFR > or =60 ml/min/1.73 m(2) (normal or mildly impaired renal function) and GFR > or = 60 ml/ min/1.73 m(2) (CKD). The independent effect of GFR, modelled both as a categorical and a continuous variable, on long-term clinical outcomes was also investigated using multivariate Cox regression analysis.

RESULTS

Nine-year all-cause and cardiac mortality rates were significantly higher in the CKD group (45.9% vs. 10.6%, P < 0.0001 and 35.4% vs. 7.1%, P < 0.0001 respectively), while there was no difference in the repeat revascularization (P = 0.27) and nonfatal Q-wave myocardial infarction (P = 0.74) rates. Multivariate analysis demonstrated an independent impact of the level of GFR on long-term mortality; adjusted 9-year all-cause and cardiac mortality increased by approximately 16% and 11%, respectively for a decrease of GFR from 120 to 60 ml/min/1.73 m(2) and by approximately 14% and 9%, respectively for a decrease of GFR from 60 to 30 ml/min/1.73 m(2).

CONCLUSIONS

The level of renal function is a strong determinant of long-term all-cause and cardiac mortality after successful PCI.

Association of endothelial shear stress with plaque thickness in a real three-dimensional left main coronary artery bifurcation model

We report for the first time a real three-dimensional reconstruction of the left main coronary artery, left main bifurcation, left anterior descending coronary artery and left circumflex coronary artery using biplane angiography and intravascular ultrasound imaging in a patient with a proximal stenosis in the left anterior descending coronary artery. By using computational fluid dynamics in the three-dimensional luminal model we computed endothelial shear stress, while plaque thickness was calculated as the difference between the three-dimensional lumen and outer vessel wall; plaque thickness was found to be inversely related to endothelial shear stress in the left main coronary artery and bifurcation. The application of our methodology for real three-dimensional reconstruction of the left main coronary artery and bifurcation is useful for investigating the relationship of hemodynamic parameters with plaque thickness in this critical coronary region.

Clinical and angiographic follow-up after overlapping implantation of polytetrafluoroethylene covered stents with drug eluting stents

Polytetrafluoroethylene-covered stents (PCS) were recently proposed as a new modality mainly for the treatment of saphenous vein graft lesions, but restenosis occurring principally at the edges restricted their clinical use in the management of coronary aneurysms and perforations.

AIMS

To investigate the safety and effectiveness of the overlapping implantation of drug-eluting stents (DES) with PCS in clinical scenarios where the latter are indicated.

METHODS

Since April 2002, when DES were introduced in clinical practice, 14 consecutive patients were -treated with overlapping implantation of PCS with DES in 3 centres. Seven patients were treated for coronary aneurysms, 5 for coronary perforations and 2 for branch occlusion. The incidence of any major adverse cardiac events defined as death, myocardial infarction (MI), and target vessel revascularisation (TVR) was retrospectively evaluated. A control angiography was available in 13 patients, and quantitative coronary angiography was performed before and after the intervention and at follow-up to evaluate restenosis rate and late loss.

RESULTS

At a mean clinical follow-up of 21.9 months there were no deaths or MI's, while one patient with occlusive restenosis underwent successful TVR (7.7%). At angiographic follow-up (mean: 9.7 months) there was one patient with restenosis (7.7%), who had a total occlusion. After excluding the patient with the occlusive restenosis mean diameter stenosis was 22.4+/-11.7% and late loss was 0.18+/-0.35 mm at follow-up. No early or late stent thrombosis occurred.

CONCLUSION

Overlapping implantation of PCS with DES seems to be a safe and effective therapeutic modality demonstrating a low incidence of clinical and angiographic restenosis.