Incomplete Apposition Research Articles

Coronary Aneurysms After Drug-Eluting Stent Implantation: Clinical, Angiographic, and Intravascular Ultrasound Findings

This study sought to assess clinical, angiographic, and intravascular ultrasound (IVUS) findings in patients developing coronary aneurysms (CANs) after drug-eluting stent (DES) implantation. The long-term safety of DES remains unsettled. This study analyzed 1,197 consecutive patients with late angiographic evaluation after DES implantation. In 15 patients (1.25%, 95% confidence interval: 0.58 to 1.93), CANs developed at follow-up. Analyses included quantitative angiography and volumetric IVUS. DES developing CANs were more frequently implanted during acute myocardial infarction and were longer than those without this outcome. The elapsed time from DES implantation to CAN diagnosis was 313 +/- 194 days. Angiographically, maximal CAN diameter measured 5.1 +/- 1.2 mm. On IVUS, CAN external elastic lamina area was 32 +/- 13.1 mm(2) and incomplete apposition area was 12.1 +/- 8.6 mm(2). Two patients presented with acute myocardial infarction secondary to DES thrombosis. Four additional patients presented with unstable angina and underwent CAN aggressive dilation (3 were also treated for concomitant in-stent restenosis). Dual antiplatelet therapy was recommended in the remaining 9 patients who were asymptomatic at CAN diagnosis, but 1 of them eventually died of cardiogenic shock after a CAN-related myocardial infarction. After a mean follow-up of 399 +/- 347 days, the 1-year event-free survival was 49 +/- 14% and was related to CAN size on IVUS. In 2 patients, CANs disappeared at repeated late angiography and IVUS showed abluminal CAN thrombosis. After DES implantation, CANs are rare and may be detected in asymptomatic patients. However, CANs are frequently associated with adverse clinical events as a result of DES restenosis and DES thrombosis. Further studies are required to determine the implications of this distinct new entity.

TREATMENT OF EXPERIMENTAL ANEURYSMS WITH AN EMBOLIC-CONTAINING DEVICE AND LIQUID EMBOLIC AGENT

To assess the feasibility and analyze angiographic and histological results of experimental aneurysms treated with an embolic-containing device (ECD) and to test a liquid embolic agent (LEA), N-butyl cyanoacrylate. Four experimental large bifurcation aneurysms and 1 large sidewall aneurysm were created in 5 dogs. These venous pouch aneurysms were occluded endosaccularly with an ECD and N-butyl cyanoacrylate. Angiographic and/or histopathological data were analyzed at 1 day (bifurcation), 1 week (bifurcation), 4 months (sidewall), 6 months (bifurcation), and 12 months (bifurcation). Aneurysm dimensions were 16 to 18 mm in length, 6 to 8 mm in width, and a neck measuring 6 to 8 mm. Immediately after the procedure, 2 of 4 bifurcation aneurysms were 100% occluded. In one case, glue had spilled into the parent artery. One occluded aneurysm recanalized at 6 months. One occluded aneurysm remained closed at 12 months. Histopathological analysis of the 6- and 12-month specimens showed adherence of glue to the aneurysm wall, no appreciable inflammatory response to the ECD, and aneurysm wall fibrosis with adventitial chronic inflammation. The aneurysm necks were covered by neointima with the presence of endothelialization. Within the limitations of this experimental study, treatment of large, wide-necked aneurysms with the ECD and LEA may be feasible. Suboptimal technique and ECD geometry can cause leakage of LEA into the parent vessel or incomplete apposition of the ECD/glue to the aneurysm wall. However, the ECD and glue injection technique did achieve complete occlusion in 1 aneurysm that persisted 1 year later. The histopathological findings in this instance are moderately encouraging. Further investigations of an ECD with N-butyl cyanoacrylate or another LEA are warranted.

Sirolimus-eluting stent implantation in small coronary arteries: A three dimensional intravascular ultrasound study from the SIRIUS trial

Aim To assess the efficacy of the sirolimus-eluting stent when implanted in smaller caliber vessels using three-dimensional intravascular ultrasound (IVUS) analysis. Methods One hundred and twenty-three patients (69 sirolimus-coated Bx Velocity and 54 control) who underwent successful three-dimensional IVUS at follow up comprised this IVUS substudy from the SIRIUS (SIRolImUS-coated Bx Velocity stent in the treatment of patients with de novo coronary artery lesions) population. To evaluate the impact of vessel size, 2 groups were created using QCA reference vessel diameter (RVD; large vessel group: RVD ≥ 2.75 mm and small vessel group: RVD < 2.75 mm). Results Sirolimus-eluting stents significantly reduced neointimal hyperplasia by the same relative magnitude within the stent in small vessels as well as in large vessels. Although sirolimus-eluting stents had favorable effects on lumen area at stent edges in larger vessels, the effect was less in smaller vessels, especially at the proximal edge. IVUS-detected adverse vessel response, such as late-acquired incomplete apposition, did not increase in smaller vessels even with relatively higher dose exposure. Conclusion Sirolimus-eluting stents showed inhibition of neointimal hyperplasia in small vessels compared to bare metal stents with no increase of vascular complications.

A more than 2-year follow-up of incomplete apposition after drug-eluting stent implantation

Incomplete stent apposition (ISA) has been demonstrated to be more common after drug-eluting stent (DES) implantation than after bare metal stent (BMS) implantation. Clinical outcomes of ISA remain controversial and the predictive accuracy of previous studies was limited by the short follow-up period of only 12-18 months. In the present study, we present the outcomes of a more than 2-year follow-up in patients with ISA after DES implantation. From the clinical and core intravascular ultrasound (IVUS) database of the hospital, we identified 76 patients who had undergone DES implantation in de novo lesions between January 2004 and June 2005 and had received IVUS examination at a scheduled 6-month follow-up. A total of 13 (17.1%) patients had documented ISA at the follow-up by IVUS. Clinical follow-up was available up to 41 months after DES implantation and up to 33 months after identification of ISA. Over a mean follow-up of (34+/-5) months (range 24-41 months), 3 of the 13 patients (23.1%) suffered from ST elevated myocardial infarction with one death. Angiography confirmed the very late stent thrombosis (ST) in the area with ISA. All the 3 patients were implanted with sirolimus eluting stents in left anterior descending artery (LAD) and the very late ST occurred at 29, 31 and 32 months after DES implantation, and separately at 20, 23 and 23 months after the identification of ISA. All of the 3 patients had antiplatelet therapy continued before suffering from ST, and had been apparently stable on antiplatelet monotherapy with aspirin for a long period following dual antiplatelet therapy with aspirin and clopidogrel for more than 12 months. ISA of DES may be associated with a high incidence of very late stent thrombosis, even in clinically stable patients with dual antiplatelet therapy of at least 12 months after the procedure.

Abstract 2153: Taxus Atlas Long Lesion: First Report of 9-Month Clinical and Angiographic Outcomes for the TAXUS Liberté 38 mm Stent for Long Lesions

Background : The TAXUS Liberté (TL) 38 mm stent, the longest drug-eluting stent, was designed with more uniform drug distribution, thinner struts and increased flexibility and conformability for use specifically in very long lesions. Long lesions have been identified as a risk factor for instent restenosis, stent thrombosis and incomplete apposition. Thus, TAXUS ATLAS Long Lesion (LL) assesses the performance of the TL 38 mm stent vs the TAXUS Express (TE) stent. Methods : TAXUS ATLAS LL is a prospective, non-randomized trial enrolling 150 pts from 24 global sites. Pts undergoing single TL stent implantation of a de novo lesion visually estimated to be 26 – 34 mm in length, with a reference vessel diameter of 2.7 – 4.0 mm, were enrolled. A subset of patients underwent IVUS at 9m. The TE Control consists of a lesion-matched cohort derived from TAXUS IV and TAXUS V. The primary endpoint is non-inferiority of 9m % diameter stenosis (%DS) of the analysis segment as determined by quanitative coronary angiography (QCA). Results : Baseline pt characteristics were well-matched between the TL and TE arms. However, the TL pts presented with longer and more complex lesions (by QCA). Procedure time was significantly shorter for TL, and the use of multiple stents was significantly less in TL vs TE. Compared to TE, TL demonstrated non-inferiority for 9m %DS, analysis segment (pre-specified non-inferiority margin = 6.89%, difference = −0.93%, upper 1-sided 95% Confidence Interval = 3.19%, p=0.0010); thus, the primary endpoint objective was met. The cardiac death or MI rate was significantly lower for TL, while other clinical and angiographic parameters were similar between the groups. There were no stent thromboses for TL. The incidence of early or late incomplete apposition was low and comparable between TL and TE. Conclusions : The TL 38 mm stent, the longest drug-eluting stent, demonstrated similar efficacy in reducing stenosis but an enhanced safety profile in very long lesions vs TE.

Abstract 2777: Optimal Expansion of the Stent is a Major Contributor to the Neointimal Coverage Following Sirolimus-eluting Stent Implantation: A Combined Study of Angioscopy and Intravascular Ultrasound

Background: Although sirolimus-eluting stent (SES) has significantly reduced in-stent restenosis by inhibiting neointimal hyperplasia, insufficient neointimal coverage after stenting may result in adverse outcomes. Determinants of neointimal coverage following SES, however, are poorly understood. Methods: We evaluated 28 SES lesions using both angioscopy and intravascular ultrasound (IVUS). Degree of neointimal coverage was judged by angioscopy at follow-up (11 ± 6 months): complete/incomplete coverage, based on whether the stent struts were embedded by the neointima. Minimal stent area (MSA), external elastic membrane (EEM), lumen cross-sectional area (CSA) and plaque burden (EEM minus lumen/EEM CSA) were measured by IVUS at stent implantation. Both proximal and distal references were used. Stent expansion was assessed by stent expansion index (SEI) as MSA/reference EEM CSA. Under-expansion was defined as SEI &lt; 0.4. Incomplete apposition was defined as the lack of contact between any strut and the underlying vessel wall. Results: Complete coverage was identified in 10 (36%), and incomplete coverage in 18 (64%). Time from the stenting to angioscopy (10 ± 5 versus 11 ± 7 months, p=0.8) as well as the lesion and procedural characteristics was similar between the complete/incomplete coverage groups. IVUS parameters were also similar, except for the final MSA (7.0±1.8mm 2 in complete versus 5.3±1.9mm 2 in incomplete , p=0.02) and lumen CSA at the distal reference site (6.1±1.4mm 2 in complete versus 4.9 ±1.2mm 2 in incomplete , p= 0.02). The frequency of incomplete apposition was similar between the groups (20% in complete versus 39% in incomplete , P= 0.4); however, SEI was significantly larger in the complete coverage than in the incomplete coverage group (0.52 ± 0.11 versus 0.39 ± 0.09, p=0.002). Stent under-expansion was identified only in 2 (20%) of the complete coverage, as compared to 67% of the incomplete coverage group (P=0.046). By multivariate logistic regression analysis, large SEI was strongly associated with complete neointimal coverage (P=0.04). Conclusion: Optimal expansion of the stent is a major contributor to the complete neointimal coverage following sirolimus-eluting stent implantation.

Neointimal coverage of bare-metal and sirolimus-eluting stents evaluated with optical coherence tomography

Objective: To analyse the neointimal coverage of sirolimus-eluting stent (SES) and bare-metal stent (BMS) visualised in vivo by optical coherence tomography (OCT). Methods: OCT images were obtained in 26 coronary...

Safety and efficacy of multiple, overlapping polymer-based paclitaxel-eluting stents

To provide insight on the patients with long lesions that received multiple, overlapping stents by reporting clinical outcomes, together with a detailed angiographic and intravascular ultrasound analysis of the overlap zone. TAXUS VI is a prospective, multicentre, double-blind, trial, specifically designed to assess outcomes of paclitaxel-eluting stents in longer lesions by randomising 446 patients (1:1) between a drug-eluting TAXUS Express2 Moderate Release (MR) and an uncoated Express2 control stent. Multiple overlapping stents were implanted in 124 patients (27.8%) and are the subject of this report. Clinical, angiographic and IVUS outcomes at nine months were compared in the overlap group for patients receiving the TAXUS Express2 MR stent and the uncoated Express2 stent. In the overlap group, mean lesion length was 25.1 mm with a mean stent length of 43.6 mm. At nine months, TVR was reduced by 94% from 25.0% to 1.6% in the TAXUS patients compared with control (p=<0.0001); TLR was reduced by 93% from 23.3% to 1.6% (p=0.0002). Binary restenosis in the stented area was reduced by 89% from 45.5% in the control patients to 4.8% in the TAXUS patients (p<0.0001). There was a trend towards a higher 30-day myocardial infarction rate in the TAXUS group (7.9% vs. 1.6%; p=0.21), but by nine months, MACE was significantly reduced by 62.0%, from 25.0% to 9.5% in favour of the TAXUS patients (p=0.0305). Late acquired incomplete apposition on IVUS was infrequent in either group and was not located in the overlap zone, nor was the finding associated with late MACE. No stent thrombosis occurred in either group. The use of multiple overlapping TAXUS MR stents appears safe and effective in the treatment of long complex coronary artery lesions.

Intravascular Ultrasound Comparison of Sirolimus-Eluting Stent Versus Bare Metal Stent Implantation in Diseased Saphenous Vein Grafts (from the RRISC [Reduction of Restenosis In Saphenous Vein Grafts With Cypher Sirolimus-Eluting Stent] Trial)

The randomized Reduction of Restenosis In Saphenous Vein Grafts with Cypher Sirolimus-Eluting Stent trial compared angiographic outcomes of sirolimus-eluting stents (SESs) versus bare metal stents (BMSs) in saphenous vein grafts (SVG). Using intravascular ultrasound (IVUS) performed during 6-month follow-up angiography, we compared the vascular effects of the 2 types of stent on SVGs. Of 75 patients (96 lesions) included, 59 patients underwent IVUS in 61 SVGs; 29 patients received 40 SESs for 34 lesions, and 30 patients received 42 BMSs for 39 lesions. IVUS parameters (diameters, areas, and volumes) were compared in the 2 groups. A specific analysis was performed for overlapping SESs. Median neointimal volume was 1.3 mm(3) (interquartile range 0 to 13.1) in SESs versus 24.5 (7.8 to 39.5) in BMSs (p <0.001). Minimal incomplete stent apposition was detected at only 3 stent edges (2 BMSs, 1 SES) next to ectatic regions of the SVG. Compared with single SESs, overlapping SESs showed significant increases in neointimal reaction, with a neointimal volume of 0.6 mm(3)/mm of stent (0.1 to 1.8) versus 0 (0 to 0.4) in single SESs (p = 0.03), and this phenomenon was mainly localized in overlapping SES segments, where neointimal volume per millimeter of stent was 1.1 mm(3)/mm (0.6 to 4.4) versus 0 (0 to 1.3) in nonoverlapping segments (p = 0.05). In conclusion, SESs effectively inhibit neointimal hyperplasia volume compared with BMSs in diseased vein grafts, without evidence of increased incomplete apposition risk. The neointimal response to overlapping SES layers seems higher than to a single SES layer.

Late incomplete apposition after drug-eluting stent implantation: incidence and potential for adverse clinical outcomes

Late-acquired incomplete stent apposition (ISA) has been documented after drug-eluting stent (DES) implantation; however, its clinical role remains controversial. We sought to investigate the incidence and long-term clinical consequences of late ISA after implantation of sirolimus- (SES) or paclitaxel-eluting stent (PES) in a non-selected population. From our database, we analysed 195 consecutive patients who underwent DES placement (175 with SES and 20 with PES) into native artery lesions and had serial intravascular ultrasound studies (IVUS) performed at index procedure and after 6-8 months. They were clinically followed for 29 +/- 15 months (median of 24.3 months, interquartile range 18.1-31.6 months). Late ISA was defined as separation of at least one stent strut from the vessel wall in a segment without a side-branch and where the immediate post-implantation IVUS revealed complete apposition of stent struts. We identified 10 patients (5.1%) with late ISA, three patients after PES, and seven patients after SES implantation. ISA was localized almost exclusively at body of the stents (nine out of 10 cases). Mean ISA volume and length were 44.5 +/- 41.9 mm(3) and 7.4 +/- 11 mm, respectively. There was a marked increase in vessel volume from 416.0 +/- 163.9 mm(3) at baseline to 514.4 +/- 247.9 mm(3) at follow-up (P = 0.001) with no significant change in plaque volume (232.4 +/- 52.7 at baseline and 226.4 +/- 22.3 mm(3) at follow-up, P = 0.3) in patients who presented with late-acquired ISA. During the follow-up period, one patient with SES and one patient with PES who presented late-acquired ISA had late stent thrombosis and acute myocardial infarction. Late-acquired ISA was observed in 5.1% of patients after DES implantation and is related to regional vessel positive remodelling. The relationship between late-acquired ISA and long-term adverse outcomes (e.g. stent thrombosis) requires further analysis.

What to Do About Late Incomplete Stent Apposition?

Acute and subacute stent thromboses have existed since the first stent implantation procedures. Initially recognized as a complication of brachytherapy, late stent thrombosis has become a public health issue only during the current era of drug-eluting stent (DES) implantation, as evidenced by the March 8, 2007, issue of the New England Journal of Medicine , which includes 5 articles, 2 perspectives, and 1 editorial discussing late DES complications. Article p 2426 During every phase of percutaneous coronary intervention, intravascular ultrasound (IVUS) has provided important insights into the mechanisms of success and reasons for failure. In this issue of Circulation , Cook et al1 continue this tradition by reporting the IVUS findings in 13 patients who developed stent thrombosis >1 year after DES implantation. They concluded, “Incomplete stent apposition is highly prevalent in patients with very late stent thrombosis after DES implantation, suggesting a role in the pathogenesis of this adverse event.” Incomplete stent apposition (ISA), synonymous with stent malapposition, is a lack of contact between stent struts and the underlying vessel wall not overlying a side branch. ISA can be quantified by measuring the number of malapposed struts; the arc subtended by the malapposed struts; the distance between the malapposed struts and the vessel wall; and the area, length, and volume of the gap between the stent and vessel wall. ISA must be differentiated from and not confused with stent underexpansion. Stent expansion is the minimum stent area by itself or compared with a predefined reference. Although this distinction may seem obvious, ISA and stent underexpansion are used interchangeably by purported experts. Although the collaborative work of Nakamura and associates2 demonstrated an unexpectedly high percentage of IVUS-detected stent underexpansion and incomplete apposition after angiographically successful bare metal stent (BMS) implantations, no study has linked acute or subacute stent …

Percutaneous Coronary Revascularization Using a Trilayer Metal Phosphorylcholine-Coated Zotarolimus-Eluting Stent

The ZoMaxx Coronary Stent System elutes the antiproliferative agent zotarolimus via a biocompatible phosphorylcholine polymer loaded onto a novel, thin, stainless steel stent platform containing an 0.0007-inch inner layer of tantalum that enhances fluoroscopic radiopacity. The objective of this single-arm prospective clinical trial was to assess the safety and performance of the ZoMaxx stent for the treatment of coronary artery stenosis. Forty consecutive patients with ischemic coronary occlusive disease due to single de novo obstructive lesions of native coronary arteries were treated with 3 x 18 mm ZoMaxx stents at the Dante Pazzanese de Cardiologie in Saõ Paulo, Brazil, between April and July 2005. Independent core laboratories analyzed quantitative coronary angiography and intravascular ultrasound results immediately after stent implantation, and after 4 months. The lesion, procedure, and device-deployment success rates were all 100% (40 of 40). There were no major adverse cardiac events during the study. Follow-up quantitative coronary angiography at 4 months revealed in-stent and in-segment late lumen losses of 0.20 +/- 0.35 and 0.17 +/- 0.35 mm, respectively. Follow-up intravascular ultrasound at 4 months revealed 6.5 +/- 6.2% neointimal volume obstruction. There were no instances of late acquired stent incomplete apposition or stent thrombosis. In conclusion, the ZoMaxx Coronary Stent can be safely implanted for the treatment of de novo coronary artery stenosis. The inhibition of neointima formation as measured by follow-up angiography and IVUS after 4 months suggests therapeutic potential for the reduction of restenosis.

Incidência de aposição incompleta persistente e tardia após implante de stents com sirolimus e zotarolimus

INTRODUÇÃO: Aposição incompleta (AI) é descrita após implante de stents farmacológicos (SF) e pode associar-se à trombose de stents. Em razão de diferentes plataformas, polímeros e fármacos utilizados, diferenças na eficácia e na segurança entre SF também são esperadas. OBJETIVO: Avaliar a incidência de AI persistente e tardia após implante de stents com sirolimus (SES) e com zotarolimus (ZES) e a evolução dos pacientes que apresentem essa alteração. MÉTODO: Análise de 242 pacientes tratados com SF (175 pacientes com SES - Cypher® - e 67 pacientes com ZES - EndeavorTM) e submetidos a ultra-sonografia intracoronária após o implante e aos seis meses. RESULTADOS: No grupo tratado com SES, 7 (4%) pacientes apresentaram AI tardia e 12 (6,8%), AI persistente. No grupo tratado com ZES, nenhum caso de AI tardia foi identificado e, em 4 pacientes, observou-se AI após o implante e que desapareceu aos seis meses. Nos pacientes com AI tardia, observou-se aumento evolutivo dos volumes do vaso (de 377,2 ± 148,9 mm³ para 431,9 ± 155,1 mm³; p = 0,51) e da placa (de 206,1 ± 51,5 mm³ para 236,9 ± 68,4 mm³; p = 0,36). O volume de hiperplasia intimal foi maior após ZES (16,6 ± 5,8 mm³ vs. 5,1 ± 5,5 mm³; p < 0,0001). Após nove meses, não ocorreram eventos cardíacos adversos nos pacientes com AI. CONCLUSÃO: A incidência de AI tardia foi de 2,9% e observada após SES. A presença de AI não esteve relacionada a eventos adversos a médio prazo.

Effect of Everolimus-Eluting Stents in Different Vessel Sizes (from the Pooled FUTURE I and II Trials)

The everolimus-eluting stent (EES) has been shown to significantly decrease neointimal proliferation at 6 months compared with the bare metal stent (BMS) in patients with de novo coronary lesions. We report mid-term outcomes based on different vessel sizes in the combined FUTURE I and II trials. In the prospective, randomized, FUTURE I trial (single center) and expanded FUTURE II trial (multicenter), 106 patients (107 lesions) were randomized to EESs (n = 49 lesions) or BMSs (n = 58 lesions). Patients were categorized into 3 groups based on preprocedure reference diameter as assessed by quantitative coronary angiography (small vessel < 2.75 mm, medium vessel 2.75 to 3.25 mm, and large vessel > 3.25 mm). At 6-month follow-up, EESs decreased in-stent late lumen loss (decreased rate range of 78% to 94%), resulting in significantly larger minimum lumen area as assessed by intravascular ultrasound (increased range of 34% to 42%) compared with the BMS across all vessel sizes. There were no cases of in-stent restenosis with EESs at any vessel size but 8 cases with BMSs (5 in small vessels). No stent thrombosis, aneurysm formation, or late stent incomplete apposition was observed in any group. The EES appears to be effective for treatment of de novo coronary lesions in decreasing neointimal proliferation at 6-month follow-up compared with BMSs, regardless of vessel size.

Bifurcation Coronary Lesions Treated With the “Crush” Technique: An Intravascular Ultrasound Analysis

We report intravascular ultrasound (IVUS) findings after crush-stenting of bifurcation lesions. Preliminary results with the crush-stent technique are encouraging; however, isolated reports suggest that restenosis at the side branch (SB) ostium continues to be a problem. Forty patients with bifurcation lesions underwent crush-stenting with the sirolimus-eluting stent. Postintervention IVUS was performed in both branches in 25 lesions and only the main vessel (MV) in 15 lesions; IVUS analysis included five distinct locations: MV proximal stent, crush area, distal stent, SB ostium, and SB distal stent. Overall, the MV minimum stent area was larger than the SB (6.7 ± 1.7 mm2vs. 4.4 ± 1.4 mm2, p < 0.0001, respectively). When only the MV was considered, the minimum stent area was found in the crush area (rather than the proximal or MV distal stent) in 56%. When both the MV and the SB were considered, the minimum stent area was found at the SB ostium in 68%. The MV minimum stent area measured <4 mm2in 8% of lesions and <5 mm2in 20%. For the SB, a minimum stent area <4 mm2was found in 44%, and a minimum stent area <5 mm2in 76%, typically at the ostium. “Incomplete crushing”—incomplete apposition of SB or MV stent struts against the MV wall proximal to the carina—was seen in >60% of non-left main lesions. In the majority of bifurcation lesions treated with the crush technique, the smallest minimum stent area appeared at the SB ostium. This may contribute to a higher restenosis rate at this location.

Vascular endoscopic and macroscopic observations after crush stenting of coronary artery bifurcations in pigs

The crush stent technique has recently been proposed to limit the development of restenosis between drug-eluting stents implanted at coronary artery bifurcations. We studied the stent expansion, apposition to the vessel, and aspect of the overlapping stents after in vivo crush stent implantation. Crush stent implantation was performed at coronary bifurcations in anesthetized swines. The treated sites were examined using intravascular ultrasound and a vascular endoscope. The stents removed from the vessel were analyzed macroscopically. After final kissing balloon inflation, an adequate apposition of the stent to the vessel wall was confirmed by vascular endoscopy and visual inspection. However, the side-branch stent was narrowed at the site of stent overlap, and the overlapping stents in the main branch created a metal mass, which could promote the development of thrombosis. The technique of crush stent implantation with additional kissing balloon inflation is feasible and promising. However, it may be limited by thrombosis and restenosis at the carina because of stent overlapping and potential incomplete apposition. Additional studies are needed to confirm the safety and long-term clinical results of this technique.

Late incomplete apposition with excessive remodeling of the stented coronary artery following intravascular brachytherapy

Intravascular brachytherapy may cause “exaggerated” vessel remodeling with late incomplete apposition in segments that have little disease, which are exposed to higher radiation doses. The long-term clinical impact of this finding is unclear.

902-2 Lesion Composition Impacts Size and Symmetry of Stent Expansion: Initial Report from the STRUT Registry

The STRUT (Stent Treatment Region assessed by Ultrasound Tomography) Registry is a multicenter study using intracoronary ultrasound (ICUS) to examine stents (STs) implanted with high pressure. Analysis of the first 32 STs in 29 patients has revealed a previously unreported relationship between the extent and symmetry of ST expansion, and the presence of localized calcium deposits in the lesion. STs were deployed with a mean pressure of 14.2 ATMs resulting in an overall residual angiographic stenosis of 8.6 ± 12%. At the end of the procedure a slow ICUS pullback (0.5–1.0 mm/sec) was performed through the ST segment. ICUS cross-sectional images were analyzed at 2.5 mm increments throughout the ST and proximal and distal reference segments. Cross-sections within the ST were characterized by ICUS as either heavily calcified (HC: arc &gt; 180° extending &gt; 5 mm) or non/mildly calcified (MC: arc 0–180°,≤ 5 mm). STexpansion was analyzed in terms of: QCA % stenosis; ICUS % diameter expansion (DE = minimum diameter in ST/nominal ST diameter × 100); ICUS % area expansion (AE = minimum area in ST/final balloon area × 100); and asymmetry (maximum divided by minimum diameter within ST). OCA ICUS % DE ICUS % AE Asymmetry MC (n = 19) 8.2 ± 9.9 83 ± 9.2 78 ± 12 0.79 ± 10 HC (n = 13) 9.5 ± 10.4 63 ± 11.7 69 ± 9 0.65 ± 0.09 significance p = NS p &lt; 0.001 p = 003 p &lt; 0.001 Incomplete ST apposition to vessel wall occurred in 7/14 (50%) of HC segments compared to 2/18 (11%) MC lesions. In MC and HC, the balloon to vessel ratio was similar (0.72 ± 0.13 vs. 0.74 ± 0.16, p = NS). In conclusion , target lesion calcification influences the overall expansion, apposition and shape of ST deployment. Potential clinical impact will be assessed by clinical and angio follow-up at 6 months.

The need to emphasize preventive medicine in future U.S. health care programs

To evaluate the acute performance of a novolimus-eluting bioresorbable scaffold (BRS) with a nominal diameter of 4.0 mm (DESolve® XL) using optical coherence tomography (OCT) in terms of appropriate scaffold deployment.Ten patients (55.6% male, mean age 60.0 y) undergoing OCT-guided scaffold implantation were enrolled consecutively in this retrospective study. Using data from the final pullback, the following indexes were calculated: mean and minimum area, residual area stenosis, incomplete strut apposition, tissue prolapse, eccentricity and symmetry indexes, strut fracture, and edge dissection. The clinical indication for the procedure was acute coronary syndrome in roughly half (55.5%) of the cases. All three main vessels were affected equally. The maximum post-dilatation balloon inflation pressure was 14.7 ± 4.2 atm. OCT analysis showed a lumen area of 11.4 ± 1.9 mm2 and a scaffold area of 11.5 ± 2.1 mm2. Mean residual area stenosis was 28.6%. No strut fractures or edge dissections were apparent. The mean eccentricity index was 0.65 ± 0.16 and the mean symmetry index 0.39 ± 0.25.The size of large vessels does not adversely influence acute mechanical performance as assessed by the eccentricity and symmetry indexes. No adverse cardiac event occurred during the hospital stay or the 30-day follow-up. It is feasible to treat large vessels with the DESolve® XL BRS.

On the influence of the tricuspid valve of the heart on the circulation of the blood

The purport of this paper is to prove experimentally that the tricuspid valve of the human heart does not, in the ordinary state of the circulation, completely prevent the reflux of blood from the ventricle into the auricle on the right side, and that the amount of regurgitation is continually varying according to the different degrees of distention of the ventricle. The author points out the anatomical differences between the auriculo-ventricular valves on the right and left sides of the heart; from the consideration of which it might have been inferred, independently of direct experiment, that while the structure of the mitral valve is adapted to close accurately all communication between the left auricle and ventricle during the contraction of the latter, that of the tricuspid valve is designedly calculated to allow, when closed, of the flow of a certain quantity of blood from the right ventricle back again into the auricle. The comparatively imperfect valvular function of these latter membranes is shown by various experiments on recent hearts, in which it was found that fluids injected, through the aorta, into the left ventricle, were perfectly retained in that cavity, by the closing of the mitral valve; but that when the right ventricle was similarly injected through the pulmonary artery, the tricuspid valves generally allowed of the escape of the fluid in streams, more or less copious, in consequence of the incomplete apposition of their margins. On repeating these experiments on different animals the author obtained similar results; but found that the imperfection of the valvular function was greater, the sooner the heart was examined after the death of the animal; and that if the trials were made after the lapse of a certain time, the rigidity which gradually supervened on the muscular fibres of the heart, and of the carneæ columnæ attached to the margins of the valves, brought them into more complete apposition and led to the accurate closing of the passage. This effect, however, was never so perfectly accomplished in the tricuspid, as in the mitral valves. The author regards this peculiarity of structure in the tricuspid valve as an express provision against the mischiefs that might result from an excessive afflux of blood to the lungs, analogous to a safety-valve; and as more especially advantageous in incipient diseased enlargements of the right ventricle. He adverts to the conditions of the heart during the fœtal state of existence, in which the same necessity of guarding against excessive pressure does not occur, and where the structures are found to correspond to the variation of functions. A similar adjustment of the right auriculo-ventricular valve to the peculiar circumstances and habits of animals may also be traced by extending the inquiry to various classes of animals.