'Optimal' directional coronary atherectomy: final results of the Optimal Atherectomy Restenosis Study (OARS)

Overview of in-hospital outcomes in patients undergoing percutaneous coronary intervention with the revived directional coronary atherectomy

OBJECTIVES

We sought to provide clinical insights on the usage rate, indications, and in-hospital outcomes of the revived directional coronary atherectomy (DCA) catheter (Atherocut™) in a Japanese nationwide percutaneous coronary intervention (PCI) registry.

BACKGROUND

Debulking devices such as the revived DCA catheter have become increasingly important in the era of complex PCI. However, little is known about PCI outcomes using a novel DCA catheter in contemporary real-world practice.

METHODS

We analyzed 188,324 patients who underwent PCI in 1112 hospitals from January to December 2018. Baseline characteristics and in-hospital outcomes of patients with stable coronary artery disease or unstable angina who underwent PCI with or without the DCA were analyzed.

RESULTS

Overall, 1696 patients (0.9%) underwent PCI with the DCA during the study period, predominantly for left main trunk or proximal left anterior descending artery lesions under a transfemoral approach. Patients in the DCA group were younger and had fewer comorbidities such as hypertension, diabetes mellitus, and chronic kidney disease than patients in the non-DCA group. Stentless PCI using the DCA with drug-coated balloon angioplasty was a preferred treatment strategy in the DCA group (50.0%). Predefined in-hospital adverse outcomes, including mortality (0.2% vs. 0.3%, p = 0.446) and periprocedural complications (1.8% vs. 1.7%, p = 0.697), were comparable between the two groups, whereas the fluoroscopy time was longer and the total contrast volume was higher in the DCA group.

CONCLUSIONS

In Japan, PCI using the revived DCA catheter is safely performed with low complication rates in patients with stable coronary artery disease or unstable angina.

Impact of directional coronary atherectomy followed by drug-coated balloon strategy to avoid the complex stenting for bifurcation lesions

Although the simple single stenting rather than complex double stenting is recommended on percutaneous coronary intervention (PCI) for bifurcation lesions, double stenting cannot always be avoided. We investigated the impact of directional coronary atherectomy (DCA), followed by drug-coated balloon (DCB) treatment to reduce the number of stents and avoid complex stenting in PCI for bifurcation lesions and short-term patency. DCA treatment without stents was attempted for 27 bifurcation lesions in 25 patients, of those, 26 bifurcation lesions in 24 patients were successfully treated and 3-month follow-up angiography and optical coherence tomography (OCT) were performed. Sixteen lesions (59.3%) were related to left main trunk distal bifurcations, and 7 (25.9%) were true bifurcation lesions. Among the true bifurcation lesions, 4 lesions (57.1%) needed 1 stent, and the other 3 lesions (42.9%) needed no stents. Among the non-true bifurcation lesions, 1 lesion (5.0%) needed bailout stent and other lesions (95.0%) needed no stents. According to DCA followed by DCB treatment, the angiographic mean diameter stenosis improved from 65.5 ± 15.0% to 7.8 ± 9.8%, and the mean plaque area in intravascular ultrasound improved from 80.4 ± 10.5% to 39.0 ± 11.5%, respectively. Angiographic and OCT late lumen loss values were 0.2 ± 0.6 mm and 1.4 ± 1.9 mm, respectively. No patient had in-hospital major adverse cardiac events (MACE) and 3-month MACE. In conclusion, compared with standard provisional side branch stenting strategy, DCA followed by DCB treatment might reduce the number of stents, avoid complex stenting for major bifurcation lesions and provide good short-term outcomes.

Impact of optimal preparation before drug-coated balloon dilatation for de novo lesion in patients with coronary artery disease

BACKGROUND

Drug eluting stent (DES) remain several problems, including stent thrombosis, stent fracture and neoatherosclerosis. Stent-less Percutaneous coronary intervention (PCI) using a drug coated balloon (DCB) is a stent-less strategy, and several trials have supported the efficacy of DCB. However, the optimal preparation before using DCB was uncertain. The aim of this study was to investigate the optimal preparation for plaque oppression/debulking before DCB dilatation for de novo coronary artery lesion.

METHODS

A total 936 patients were treated using DCB from 2014 to 2017 at our institution. Among them, we analyzed 247 patients who underwent PCI using DCB alone for de novo lesion. The primary end point of this study was target lesion failure (TLF).

RESULTS

The area under the receiver operating characteristic (ROC) curve (AUC) was used to determine the optimal cutoff value of % plaque area to predict TLF. ROC curve analysis revealed plaque area ≥ 58.5% (AUC, 0.81) were associated with TLF. Eligible 188 patients were divided into 2 groups (plaque area ≥ 58.5% [n = 38] and <58.5% [n = 150]) according to IVUS data before using DCB. TLF was significantly higher in plaque area ≥ 58.5% group than in <58.5% group (P < 0.01). Multivariable analysis selected plaque area ≥ 58.5% as an independent predictor of TLF (hazard ratio 7.59, P < 0.01).

CONCLUSIONS

Lesion preparation achieving plaque area < 58.5% was important in stent-less PCI using DCB.

Efficacy of drug-coated balloon angioplasty after directional coronary atherectomy for coronary bifurcation lesions (DCA/DCB registry)

OBJECTIVES

To evaluate the efficacy and safety of additional drug-coated balloon (DCB) angioplasty after directional coronary atherectomy (DCA) for coronary bifurcation lesions.

BACKGROUND

The optimal therapy for bifurcation lesions has not been established, even in the drug-eluting stent era. DCA possibly prevents plaque and carina shift in bifurcation lesions by plaque debulking; however, the efficacy of combined DCA and DCB (DCA/DCB) for bifurcation lesions remains unclear.

METHODS

This multicenter registry retrospectively recruited patients with bifurcation lesions who underwent DCA/DCB and follow-up angiogram at 6-15 months. The primary endpoint was the 12-month target vessel failure (TVF) rate. The secondary endpoints were procedure-related major complications, major cardiovascular events at 12 months, restenosis at 12 months, target lesion revascularization (TLR) at 12 months, and target vessel revascularization (TVR) at 12 months.

RESULTS

We enrolled 129 patients from 16 Japanese centers. One hundred and four lesions (80.6%) were located around the left main trunk bifurcations. No side branch compromise was found intraoperatively. Restenosis was observed in three patients (2.3%) at 12 months. TLR occurred in four patients (3.1%): 3 (2.3%) in the main vessel and 1 (0.8%) in the ostium of the side branch at 12 months. TVF incidence at 12 months was slightly higher in 14 patients (10.9%), and only two patients (1.6%) had symptomatic TVR. One patient (0.8%) had non-target vessel-related myocardial infarction.

CONCLUSIONS

Our data suggested that DCA/DCB provided good clinical outcomes and minimal side branch damage and could be an optimal non-stent percutaneous coronary intervention strategy for bifurcation lesions.

Short-term outcome of percutaneous coronary intervention with directional coronary atherectomy followed by drug-coated balloon: a preliminary report

Directional coronary atherectomy (DCA) is a unique technique used in percutaneous coronary intervention (PCI) which involves the removal of plaque from the coronary artery. Treatment with a drug-coated balloon (DCB) appears to be effective, especially when a predilatation of the lesion is performed appropriately. We hypothesize that the combination therapy of DCA with DCB is an effective strategy in PCI. PCI with DCA followed by DCB was performed for 23 patients from December 2014 to April 2017. All DCA procedures were performed under the guidance of intravascular ultrasound (IVUS) findings and all procedures were successfully performed without incurring major complications such as a coronary perforation. Plaque area (PA) was reduced from 77.3 ± 10.4% at baseline to 50.9 ± 9.2% after DCA and luminal cross-sectional area (CSA) after PCI was enlarged from 3.6 ± 1.8 to 9.3 ± 3.3 mm². Follow-up coronary angiography (CAG) performed at 6–10 months showed no cases having incurred restenosis. Plaque area at follow-up CAG was 52.0 ± 8.5% and luminal CSA was 9.5 ± 2.1 mm². There were no cases undergoing target vessel revascularization (TVR) and target lesion revascularization (TLR) during the follow-up periods. PCI with DCA followed by DCB might be an effective strategy for de novo lesions.

Rotational atherectomy in very long lesions: Results for the ROTATE registry

BACKGROUND

Rotational atherectomy (RA) is relatively contraindicated in patients with lesions ≥25 mm of length. Aim of this study was to evaluate RA safety and efficacy in this subset of patients with new technology and devices.

METHODS AND RESULTS

From April 2002 to August 2013, the ROTATE registry included all consecutive patients undergoing RA in 8 centres. They were divided into shorter lesion group (SLG, lesions < 25 mm) and longer lesion group (LLG, lesions ≥ 25 mm). The angiographic success (AS) was the primary end point. Procedural complications (PC), a composite end point of procedural perforation, slow flow/no flow, and in-hospital major acute cardiovascular events (MACE), were secondary end points, along with death, nonfatal MI, target lesion revascularization, and MACE during follow-up. Sensitivity analysis was performed according to generation of DES. 1186 patients were included: 51.5% in SLG and 48.4% in LLG. Mean age was 70.4 ± 9.3 years, 64.5% were male. AS and PC did not differ between the two groups (93% vs 91%, p = 0.24 and 9.8 vs 9.4%, p = 0.84). During follow-up (27.6 ± 22.9 months), MACE did not differ between the two groups (28% vs 29.1%, p = 0.95). At multivariate analysis chronic kidney disease, male gender increased risk of MACE (HR 1.94, IQR 1.29-2.0, p = 0.01, HR 0.52, IQR 0.34-0.79, p = 0.01) while second-generation DES seemed protective (HR 0.53, IQR 0.31-0.88, p = 0.02). Data were confirmed at sensitivity analysis for second-generation DES (759 pts, 63.9%). No differences were found in this subpopulation between the two groups in term of AS, PC, and long-term MACE (93.6% vs 93.5%, p = 0.28, 11.9% vs 9.4%, p = 0.32 and 25.5% vs 23.9%, p = 0.72, respectively).

CONCLUSIONS

Treating coronary lesions ≥ 25 mm length with RA does not impact short- and long-term outcome, in particular, in patients with second-generation DES. © 2016 Wiley Periodicals, Inc.

Pharmacological prevention of peri-, and post-procedural myocardial injury in percutaneous coronary intervention

In recent years, percutaneous coronary intervention (PCI) has become a well-established technique for the treatment of coronary artery disease. PCI improves symptoms in patients with coronary artery disease and it has been increasing safety of procedures. However, peri- and post-procedural myocardial injury, including angiographical slow coronary flow, microvascular embolization, and elevated levels of cardiac enzyme, such as creatine kinase and troponin-T and -I, has also been reported even in elective cases. Furthermore, myocardial reperfusion injury at the beginning of myocardial reperfusion, which causes tissue damage and cardiac dysfunction, may occur in cases of acute coronary syndrome. Because patients with myocardial injury is related to larger myocardial infarction and have a worse long-term prognosis than those without myocardial injury, it is important to prevent myocardial injury during and/or after PCI in patients with coronary artery disease. To date, many studies have demonstrated that adjunctive pharmacological treatment suppresses myocardial injury and increases coronary blood flow during PCI procedures. In this review, we highlight the usefulness of pharmacological treatment in combination with PCI in attenuating myocardial injury in patients with coronary artery disease.

Directional coronary atherectomy: a time for reflection. Should we let it go?

A series of interventional tools have emerged since the advent of percutaneous coronary angioplasty. Several are fundamental and used routinely, while others less favourable have fallen short of mainstream therapy and/or have settled as a niche device. We present an overview of the evolution of directional coronary atherectomy (DCA), a unique device that was originally conceived in 1984 to solve the limitations of balloon angioplasty. Unfortunately, we have witnessed its use fall significantly out of favour due to premature and controversial study results. In many interventional laboratories DCA is no longer available. However, we strongly feel that allowing DCA to join the list of extinct interventional tools would be very unfortunate. We, herein, present a series of complex percutaneous coronary procedures to illustrate the convenience of DCA use as a lesion-specific niche device. Finally, DCA offers a valuable distinct clinical research function as it allows for in vivo pathological coronary tissue examination. In conclusion, we plead for its continued production and use as an interventional niche device for the wellbeing of our patients.

Atherectomy for infrainguinal peripheral artery disease

Compared to conventional percutaneous transluminal angioplasty (PTA) and stent implantation for arterial occlusive diseases, atherectomy offers the theoretical advantages of eliminating stretch injury on arterial walls and reducing the, rate of restenosis. Historically, however, neither rotational nor directional atherectomy, whether used alone or with adjunctive PTA, has shown any significant long-term benefit over PTA alone in the coronary or peripheral arteries. However, the SilverHawk Plaque Excision System has produced positive results in single-center prospective registries of patients with femoropopliteal and infrainguinal lesions, with reduced adjunctive PTA, minimal adjunctive stenting, and competitive 6-month and 12-month patency rates. In the observational nonrandomized TALON (Treating Peripherals with SilverHawk: Outcomes Collection) registry, freedom from target lesion revascularization was 80% for 87 patients at 12 months. Questions remaining for further research with this device include more accurate determination of an event rate for distal embolization, the appropriate use of distal protection, the value of and appropriate circumstances for adjunctive angioplasty, and definitive patency and clinical outcomes. Other atherectomy devices are discussed.

Long-term clinical efficacy of cutting balloon angioplasty followed by bare metal stent implantation for treating ostial left anterior descending artery lesions

BACKGROUND

Drug-eluting stents (DES) are superior to bare metal stents (BMS) for treating ostial left anterior descending artery (LAD) lesions, but DES is not suitable for all patients in real life practice.

HYPOTHESIS

We hypothesize that cutting balloon angioplasty (CBA) followed by BMS (CBA + BMS) for treating ostial LAD lesions is an alternative strategy.

METHODS

In our study, 101 consecutive patients (51 with DES and 50 with CBA + BMS) with ostial LAD stenting were included for retrospective investigation between November 2003 and May 2005. The target vessel diameter was > or =3.0 mm.

RESULTS

We compared the DES group with the CBA + BMS group, the rates of restenosis (10.3% versus 17.9%, p = 0.386), target lesion revascularization (TLR) (5.88% versus 10%, p = 0.487) and major adverse cardiac events (MACE) (7.84% versus 12%, p = 0.525) were similar at 6-8 months angiographic follow-up, but there were higher bleeding events in the DES group (p = 0.033). During a 2-year clinical follow-up, no myocardial infarction occurred in the 2 groups, the rates of TLR (7.84% versus 10%, p = 0.741) and MACE (9.8% versus 12%, p = 0.723) were also similar. The MACE-free survival rate was 90.2% versus 88 % (p = 0.723).

CONCLUSIONS

The CBA + BMS combination has a good long-term clinical effect in the treatment of ostial LAD lesions; it might be an alternative strategy for patients with contraindication for DES implantation, or patients who cannot endure long-term dual antiplatelet medication, or in elderly patients.

Factor Seven Activating Protease (FSAP) expression in human monocytes and accumulation in unstable coronary atherosclerotic plaques

OBJECTIVE

The Factor Seven Activating Protease (FSAP) is known to influence fibrinolysis and to play a critical role in the inhibition of vascular smooth muscle cell (VSMC) proliferation and migration as well as neointima formation. In order to define the role of FSAP in vascular pathophysiology we have investigated the expression of FSAP protein and mRNA in human vascular cells and coronary atherosclerotic plaques with defined clinical features.

METHODS AND RESULTS

Directional coronary atherectomy (DCA) specimens from 40 lesions were analyzed for FSAP antigen and mRNA expression. Higher level of FSAP mRNA (p<0.001) as well as FSAP immunostaining (p<0.005) was observed in patients with acute coronary syndromes compared to patients with stable angina pectoris. FSAP antigen was found to be focally accumulated in hypocellular and lipid-rich areas within the necrotic core of atherosclerotic plaques. FSAP was also co-localized with CD11b/CD68 expressing cells in macrophage-rich shoulder regions of the plaques. Monocyte-derived macrophages expressed FSAP in vitro and this was further induced by pro-inflammatory mediators.

CONCLUSIONS

FSAP accumulation in coronary atherosclerotic lesions is due to either local synthesis by monocytes/macrophages, or uptake from the plasma due to plaque hemorrhage. The higher expression of FSAP in unstable plaques suggests that it may destabilize plaque through reducing VSMC proliferation/migration and altering the hemostatic balance.

Neointimal expression of rapamycin receptor FK506-binding protein FKBP12: postinjury animal and human in-stent restenosis tissue characteristics

Despite excellent clinical results for sirolimus (rapamycin)-eluting stents, the exact mechanisms of antirestenotic activity and affected cellular targets are incompletely understood. Therefore, we determined the presence and tem- porospatial expression pattern of FKBP12, the primary intracellular receptor of rapamycin, in rat carotid arteries after balloon injury, as well as in human in-stent restenosis and primary stable coronary atheroma. FKBP12 expression was assessed by immunohistochemistry. Rat carotid arteries revealed maximal expression in 57.7 +/- 4.0% of neointimal cells at day 7. A large proportion of these FKBP12+ cells showed luminally confined co-expression with dendritic cell markers. Despite a considerably thicker neointima at day 28, presence of FKBP12 decreased (8.5 +/- 1.9%, p = 0.02) with a scattered pattern in luminal and deep neointima. Likewise, human in-stent restenosis atherectomy specimens (time after stent implantation 2-12 months) revealed a comparable extent of cellular rapamycin receptor expression (9.3 +/- 1.0%) that significantly differed from that found in primary stable atheroma (1.3 +/- 0.4%, p < 0.001). In conclusion, the rapamycin receptor is predominantly present during early neointima formation, while mature neointimal atheromas show a relatively low expression without confinement to luminal areas. Co-expression of FKBP12 and dendritic cell markers suggests that dendritic cells may be another important target for early and long-term rapamycin effects.

A novel approach using atherectomy for chronic total occlusion of the brachial artery: a case report

Chronic upper limb ischemia is uncommon, and is most often secondary to subclavian artery stenosis. Percutaneous intervention for subclavian stenosis usually includes balloon angioplasty and stent implantation. Brachial artery stenosis is even more scarce and accounts for approximately 12% of symptomatic upper extremity ischemia. Because it is rare, the optimal treatment strategy for brachial artery stenosis remains uncertain. We describe a case of chronic brachial artery ischemia due to atherosclerotic disease treated with the SilverHawk plaque excision system and review the available data regarding its use.

Cutting-balloon angioplasty effectively facilitates the interventional procedure and leads to a low rate of recurrent stenosis in ostial bifurcation coronary lesions: A subgroup analysis of the NICECUT multicenter registry

BACKGROUND

Displacement of plaque is a major concern during coronary intervention of ostial bifurcation lesions. For this reason, angioplasty involves complex stenting procedures, which may trigger development of restenosis in a previously non-diseased parent vessel.

OBJECTIVES

To examine, whether plaque displacement may be prevented by scoring atherosclerotic plaque with a cutting-balloon (CB) stand-alone procedure.

METHODS

Data of patients with Duke E and B type ostial bifurcation lesions (>/=70% stenosis involving a diagonal and/or marginal branch >2 mm deriving from a non-diseased parent vessel), who were treated with CB as stand-alone procedure within the prospective NICECUT multicenter trial were analyzed. Primary endpoint was the rate of binary stenosis and target lesion revascularization (TLR). Secondary endpoints were procedural success and major adverse cardiac events (MACE) at 6-months follow-up.

RESULTS

63 out of 65 lesions (56 patients) were successfully amenable to treatment with CB (96.4% procedural success). 76.9% of patients were successfully treated with CB as a stand-alone procedure, while provisional stenting was necessary in 23.1%. At follow-up, binary stenosis was found in 23.2%, among the total population. Total rate of TLR and MACE were 7.7% and 3.6%, respectively, compared to 4.0% and 2.0% in patients for whom CB stand-alone procedure was feasible, while it was 20.0% and 6.7% for stented lesions.

CONCLUSIONS

CB angioplasty as a stand-alone procedure may facilitate interventional treatment of ostial bifurcation lesions and may help to avoid complex stenting procedures. It is associated with a low rate of binary stenosis and TLR.

Impact of histological plaque characteristics on intravascular ultrasound parameters at culprit lesions in coronary artery disease

Prior intravascular ultrasound (IVUS) studies have demonstrated that a positive remodeling pattern of a culprit lesion is observed more frequently in acute coronary syndrome (ACS) than stable angina (SA). However, the relationship between the plaque morphology detected by IVUS and the histological type of atherosclerotic plaque has not been well defined. This is a prospective study on 37 consecutive patients who underwent directional coronary atherectomy. The 37 patients were divided into 2 groups; 21 patients with SA and 16 with ACS. Vessel and plaque cross sectional area were measured at the culprit lesion and the remodeling index (RI) was calculated by IVUS. The plaque tissue was assessed for the presence of inflammatory cells and lipids, and the presence of each was scored as 0 (absent), 1 (sparse), 2 (dense), or 3 (predominant). The RI of the patients with ACS was higher than that of SA. Inflammatory cells were present to a greater extent in patients with ACS. Inflammatory cells and lipids were significantly correlated with the RI (Inflammatory cell score grade > or = 2 patients; 1.14 +/- 0.13 versus grade 0 patients; 0.87 +/- 0.24, and grade 1 patients; 0.93 +/- 0.17, P < 0.01 and lipid score grade > or = 2 patients; 1.13 +/- 0.17 versus grade 0 patients; 0.85 +/- 0.18, P < 0.001 and grade 1 patients; 0.95 +/- 0.19, P < 0.05). The results clearly indicate that the evaluation of vessel morphology by vascular imaging is an important indicator of plaque instability.

Directional atherectomy facilitates the interventional procedure and leads to a low rate of recurrent stenosis in left anterior descending and left circumflex artery ostium stenoses: subgroup analysis of the FLEXI-CUT study

OBJECTIVES

To examine by retrospective analysis of data from the FLEXI-CUT monocentre registry whether atherectomy can effectively simplify complex stent implantation in ostial bifurcation lesions by reducing the procedure to stenting of the left anterior descending (LAD) or left circumflex (LCX) artery ostium alone.

PATIENTS AND METHODS

All patients who had been enrolled in the prospective FLEXI-CUT study (directional atherectomy with adjunctive balloon angioplasty) were retrospectively analysed on the basis of significant LAD or LCX ostial stenosis (>or= 70% stenosis) deriving from an undiseased left main stem. The primary combined end point was the rate of target lesion revascularisation (TLR) and binary restenosis; secondary end points were procedural success and major adverse cardiac events (MACE) at the six-month follow up.

RESULTS

Of 30 patients enrolled with significant LAD or LCX ostium stenosis, 29 were effectively treated with directional atherectomy (96.7% procedural success). All patients underwent single-vessel stenting procedures of solely the LAD or LCX ostium. At follow up, binary stenosis was 25% (6 of 24), TLR (angiographic plus clinical) 10.3% (3 of 29) and total MACE 6.9% (2 of 29).

CONCLUSIONS

Directional atherectomy with single-vessel stenting procedures facilitates the interventional treatment of LAD and LCX ostium stenosis, and leads to remarkably low TLR and binary stenosis at follow up.

Guidelines for percutaneous coronary interventions. The Task Force for Percutaneous Coronary Interventions of the European Society of Cardiology

In patients with stable CAD, PCI can be considered a valuable initial mode of revascularization in all patients with objective large ischaemia in the presence of almost every lesion subset, with only one exception: chronic total occlusions that cannot be crossed. In early studies, there was a small survival advantage with CABG surgery compared with PCI without stenting. The addition of stents and newer adjunctive medications improved the outcome for PCI. The decision to recommend PCI or CABG surgery will be guided by technical improvements in cardiology or surgery, local expertise, and patients' preference. However, until proved otherwise, PCI should be used only with reservation in diabetics with multi-vessel disease and in patients with unprotected left main stenosis. The use of drug-eluting stents might change this situation. Patients presenting with NSTE-ACS (UA or NSTEMI) have to be stratified first for their risk of acute thrombotic complications. A clear benefit from early angiography (<48 h) and, when needed, PCI or CABG surgery has been reported only in the high-risk groups. Deferral of intervention does not improve outcome. Routine stenting is recommended on the basis of the predictability of the result and its immediate safety. In patients with STEMI, primary PCI should be the treatment of choice in patients presenting in a hospital with PCI facility and an experienced team. Patients with contra-indications to thrombolysis should be immediately transferred for primary PCI, because this might be their only chance for quickly opening the coronary artery. In cardiogenic shock, emergency PCI for complete revascularization may be life-saving and should be considered at an early stage. Compared with thrombolysis, randomized trials that transferred the patients for primary PCI to a 'heart attack centre' observed a better clinical outcome, despite transport times leading to a significantly longer delay between randomization and start of the treatment. The superiority of primary PCI over thrombolysis seems to be especially clinically relevant for the time interval between 3 and 12 h after onset of chest pain or other symptoms on the basis of its superior preservation of myocardium. Furthermore, with increasing time to presentation, major-adverse-cardiac-event rates increase after thrombolysis, but appear to remain relatively stable after primary PCI. Within the first 3 h after onset of chest pain or other symptoms, both reperfusion strategies seem equally effective in reducing infarct size and mortality. Therefore, thrombolysis is still a viable alternative to primary PCI, if it can be delivered within 3 h after onset of chest pain or other symptoms. Primary PCI compared with thrombolysis significantly reduced stroke. Overall, we prefer primary PCI over thrombolysis in the first 3 h of chest pain to prevent stroke, and in patients presenting 3-12 h after the onset of chest pain, to salvage myocardium and also to prevent stroke. At the moment, there is no evidence to recommend facilitated PCI. Rescue PCI is recommended, if thrombolysis failed within 45-60 min after starting the administration. After successful thrombolysis, the use of routine coronary angiography within 24 h and PCI, if applicable, is recommended even in asymptomatic patients without demonstrable ischaemia to improve patients' outcome. If a PCI centre is not available within 24 h, patients who have received successful thrombolysis with evidence of spontaneous or inducible ischaemia before discharge should be referred to coronary angiography and revascularized accordingly--independent of 'maximal' medical therapy.

Vascular restenosis - striving for therapy

Restenosis is the limiting entity following coronary angioplasty. It is associated with significant morbidity, mortality and cost, and thus represents a major clinical and economical problem. Despite technical improvements, restenosis after conventional balloon angioplasty occurs in 30 - 60% of cases. Coronary stenting was able to reduce the incidence by approximately 30%; nevertheless, some 250,000 patients experience in-stent restenotic lesions/year worldwide. In-stent restenosis has been recognised as very difficult to manage, with a repeat restenosis rate of 50%, regardless of the angioplasty device used. So far, only vascular brachytherapy has convincingly reduced the incidence of repeat in-stent restenosis (by 50%) and thus, has emerged as the gold standard of therapy. The introduction of drug-eluting stents has shown a great deal of promise for the treatment of both de novo and restenotic lesions, with reported restenosis rates of < 10%, and benefit for virtually all patient subsets at a higher risk of restenosis. This review outlines the pathophysiology, epidemiology and predictors of the restenosis process, and places emphasis on the various treatment options for its prevention and therapy.

Pathogen burden, inflammation, proliferation and apoptosis in human in-stent restenosis. Tissue characteristics compared to primary atherosclerosis

Pathogenic events leading to in-stent restenosis (ISR) are still incompletely understood. Among others, inflammation, immune reactions, deregulated cell death and growth have been suggested. Therefore, atherectomy probes from 21 patients with symptomatic ISR were analyzed by immunohistochemistry for pathogen burden and compared to primary target lesions from 20 stable angina patients. While cytomegalovirus, herpes simplex virus, Epstein-Barr virus and Helicobacter pylori were not found in ISR, acute and/or persistent chlamydial infection were present in 6/21 of these lesions (29%). Expression of human heat shock protein 60 was found in 8/21 of probes (38%). Indicated by distinct signals of CD68, CD40 and CRP, inflammation was present in 5/21 (24%), 3/21 (14%) and 2/21 (10%) of ISR cases. Cell density of ISR was significantly higher than that of primary lesions (977 +/- 315 vs. 431 +/- 148 cells/mm(2); p < 0.001). There was no replicating cell as shown by Ki67 or PCNA. TUNEL(+) cells indicating apoptosis were seen in 6/21 of ISR specimens (29%). Quantitative analysis revealed lower expression levels for each intimal determinant in ISR compared to primary atheroma (all p < 0.05). In summary, human ISR at the time of clinical presentation is characterized by low frequency of pathogen burden and inflammation, but pronounced hypercellularity, low apoptosis and absence of proliferation.

Prevention of restenosis after coronary angioplasty

PURPOSE OF REVIEW

Despite numerous advances in coronary interventional techniques, the frequent occurrence of restenosis continues to plague interventional cardiology. With the widespread use of drug-eluting stents, there is a need to reexamine critically the roles of the various interventional techniques currently available.

RECENT FINDINGS

Drug-eluting stents have dramatically reduced the rates of restenosis and target vessel revascularization in a wide spectrum of patients with varying lesion morphologies. However, when restenosis does occur, it still tends to be dependent on the same factors that predict restenosis with bare metal stenting. The routine use of drug-eluting stents entails high initial costs to the health care system. Debulking as a means to improve outcomes after angioplasty has not lived up to expectations. Gene therapy is rapidly evolving into a viable means to reduce neointimal proliferation after angioplasty.

SUMMARY

Careful patient selection and attention to the procedure of stent deployment optimize the results of angioplasty with drug-eluting stents. Because of cost considerations, drug-eluting stents should be used in patients who are expected to have the greatest absolute benefit. In this context, when judiciously used, conventional balloon angioplasty and bare metal stenting still have a definite role in the management of patients with obstructive coronary artery disease.

Comparison of directional coronary atherectomy and stenting versus stenting alone for the treatment of de novo and restenotic coronary artery narrowing

Late lumen loss after directional coronary atherectomy (DCA) is mainly determined by arterial remodeling. We hypothesized that stent implantation after optimal lesion debulking could be an effective approach to reduce restenosis. A total of 753 patients with de novo or restenotic coronary lesions were prospectively randomized to DCA plus stenting (n = 381) or stenting alone (n = 372). The patients were followed for 12 months. Procedural success was achieved in 91.5% versus 97.3% (p = 0.0007) of patients treated with DCA plus stent versus stent alone. Optimal atherectomy (<20% residual stenosis) was achieved in 26.5% of patients. The final minimal luminal diameter and the acute gain were similar in the 2 groups. There was no increase in 30-day major adverse cardiac events in the DCA plus stent group (3.9% vs 2.4%, p = 0.30). The primary end point, angiographic restenosis at 8 months, occurred in 26.7% of patients treated with DCA plus stents and in 22.1% of patients treated with stents alone (p = 0.237). Clinical follow-up to 1 year showed no difference in mortality (1.3% vs 0.8%, p = 0.725), acute myocardial infarction (4.2% vs 3.5%, p = 0.706), and target vessel failure (composite of death, Q-wave myocardial infarction, and target vessel revascularization) (23.9% vs 21.5%, p = 0.487) between patients with DCA plus stents and those with stents alone. This study failed to support the hypothesis that DCA before stenting lowers the angiographic restenosis rate compared with stents alone. At 12-month follow-up, there were no significant differences between the 2 groups in rates of death, reinfarction, or target vessel failure.

Quantitative angiographic and intravascular ultrasound study >5 years after directional coronary atherectomy

Aggressive and optimal directional coronary atherectomy (DCA) using intravascular ultrasound (IVUS) guidance provides favorable outcomes within 1 year. However, no previous data are available on the changes that occur in target lesions for the long term after stand-alone DCA. This study's aim evaluates, using quantitative angiography and intravascular ultrasonography, the natural history of changes that occur in target lesions between short- (about 6 months) and long-term (>5 years) follow-up angiography after stand-alone DCA. Of 186 patients (221 lesions) with successful stand-alone DCA, 48 patients (53 lesions) underwent revascularization within 6 months, and 14 patients subsequently died, leaving a study population of 124 patients (154 lesions). Complete quantitative coronary angiography (QCA) was obtained in 91 patients (101 lesions) and complete serial IVUS assessment was obtained for 38 lesions before and after intervention and during follow-up. From short- to long-term follow-up angiography, the minimal luminal diameter significantly increased (from 2.12 to 2.56 mm; p <0.0001); lesion subgroups with >30% diameter stenosis at short-term follow-up angiography showed significant late regression as assessed by QCA. Serial IVUS assessment revealed that the vessel cross-sectional area did not change (from 17.3 to 17.4 mm(2); p = NS); however the lumen cross-sectional area significantly increased (from 7.3 to 9.5 mm(2); p <0.0001) due to the reduction of plaque plus media cross-sectional area (from 10.0 to 7.9 mm(2); p <0.0001). The change in lumen cross-sectional area correlated with the change in plaque plus media cross-sectional area (r = -0.686, p <0.0001). Target lesions show late regression due to plaque reduction at >5 years after stand-alone DCA.

Percutaneous coronary intervention: historical perspectives, current status, and future directions

In the twenty-six years since Gruntzig introduced a simple balloon angioplasty technique, percutaneous coronary intervention has undergone extraordinary growth and has now surpassed bypass surgery in frequency of performance. Several critical breakthrough technologies account for this remarkable progress: intracoronary stents have increased success rates and reduced restenosis, adjunctive antiplatelet therapy has reduced periprocedural complications, and restenosis after stent placement has been effectively treated with local radiation. Most recently, drug-eluting stents coated with cell-cycle inhibitors have shown great promise for further reducing restenosis, possibly to negligible levels.

Intravascular ultrasound-guided directional coronary atherectomy for unprotected left main coronary stenoses with distal bifurcation involvement

Stent implantation in unprotected left main coronary artery (LMCA) bifurcation lesions may improve procedural and late clinical outcomes. However, concerns regarding stent-related complications, such as stent jail, subacute thrombosis, and in-stent restenosis remain. Optimal debulking by directional coronary atherectomy (DCA) with intravascular ultrasound (IVUS) guidance may be effective in this complex lesion subset, but this strategy has not yet been established. Our objective was to evaluate the safety and efficacy of IVUS-guided DCA for unprotected LMCA stenoses with distal bifurcation involvement. A total of 67 consecutive patients were included in this study and procedural success was achieved in all cases. Two cardiac deaths (2.9%) were noted and 3 patients (4.5%) underwent repeat angioplasty during hospitalization. There was no Q-wave myocardial infarction or emergency bypass surgery. Non-Q-wave myocardial infarction (creatine kinase-MB >3 times normal) occurred in 13.4% of patients. Stent implantation was necessary in 17 cases (25.4%) to achieve an optimal result. IVUS showed an improved lumen cross-sectional area and a low plaque burden in the LMCA after intervention. All-cause mortality, angiographic restenosis, and the target lesion revascularization rates at 6 months were 7.4%, 23.8%, and 20.0%, respectively. With IVUS guidance, aggressive DCA can be performed safely in unprotected LMCA bifurcation lesions, and optimal angiographic and IVUS results can be achieved with low residual plaque burden, which leads to a low restenosis rate. Optimal lesion debulking by DCA does not necessarily need adjunctive stenting in this specific anatomic subset.

Initial experience with a new 8 French-compatible directional atherectomy catheter: Immediate and mid-term results

The purpose of this study was to evaluate the safety and efficacy of the new Fox Hollow atherectomy device (FHT) designed for more efficient and easier plaque removal. The FHT has short rigid section and low-profile cutter mounted on a monorail catheter. The FHT catheter was utilized in 77 patients with 98 lesions. Mean reference vessel diameter was 2.75 +/- 0.51 mm. Successful atherectomy with tissue retrieval was performed in 94 lesions (96%). Following atherectomy, mean diameter stenosis was reduced from 71.1% to 31.9% and further to 10.4% following adjunctive treatment. Angiographic complications were one coronary perforation and one adventitial staining, both successfully treated with prolong balloon inflation and stent implantation. Nine patients (11.7%) had in-hospital non-Q-wave myocardial infarction (MI). One patient died (1.3%) for noncardiac reasons and one had MI (1.3%) at 6-month follow-up. Target lesion revascularization was required in 13 (13.8%) lesions and target vessel revascularization in 15 (20.3%) patients. There was target vessel failure in 17 (23.0%) patients. Plaque debulking with the FHT catheter can be performed safely and effectively in relatively small vessels and complex lesions located in mid-distal artery segments with 6-month clinical outcome similar to prior atherectomy devices.

Clinical and angiographic outcome of directional atherectomy followed by stent implantation in de novo lesions located at the ostium of the left anterior descending coronary artery

BACKGROUND

Lesions located at the ostium of the left anterior descending coronary artery (LAD) are considered an ideal target for directional atherectomy (DCA), but few data are available about the value of using this strategy before stenting in comparison with stenting alone.

OBJECTIVES

To investigate the immediate and mid term clinical and angiographic results of DCA followed by stent implantation for ostial LAD lesions.

DESIGN

Retrospective comparison of the immediate and mid term angiographic and clinical results of a series of 117 consecutive patients with de novo lesions located at the ostium of the LAD. Of these, 46 underwent DCA before stenting and 71 were treated with stenting alone.

RESULTS

Technical success in the two groups was similar at around 98%. DCA plus stenting provided a larger minimum lumen diameter at the end of the procedure than stenting alone (3.57 (0.59) mm v 3.33 (0.49) mm, p = 0.022). There were no differences for in-hospital major adverse events (MACE) (7.5% for atherectomy plus stenting, and 5.3% for stenting alone; p = 0.41). All patients had clinical follow up at a mean of 7.9 (2.7) months. Angiographic follow up was done in 89 patients (76%) at a mean of 5.9 (2.2) months. The atherectomy plus stenting group had a larger minimum lumen diameter than the stenting group (2.79 (0.64) mm v 2.26 (0.85) mm, p = 0.004) and a lower binary restenosis rate (13.8% v 33.3%, p = 0.031). Six month MACE were reduced in the atherectomy plus stenting group (8.7% v 23.9%, p = 0.048).

CONCLUSIONS

Debulking before stenting in de novo lesions located at the ostium of the LAD is safe and is associated with a high rate of technical success. Follow up data show that DCA plus stenting results in a significantly larger minimum lumen diameter and a lower incidence of restenosis than stenting alone.

New approaches to preventing restenosis

For over a quarter of a century percutaneous coronary interventions have been used to treat patients with coronary artery disease, yet restenosis continues to be a problem. This review discusses the advances being made to overcome restenosis, particularly the development of drug eluting stents

Acute and Long-Term Outcomes of Rotational Atherectomy in Small (<3.0 mm) Coronary Arteries

Conventional balloon angioplasty (BA) of small coronary arteries (SCA) is followed by a high rate of restenosis. Rotational atherectomy may be effective as an alternate treatment of stenoses unsuitable for other devices. The purpose of this study was to assess the efficacy of RA in the treatment of SCA. A retrospective analysis was performed of 226 lesions in 159 consecutive patients who underwent RA of SCA (mean diameter = 2.36 +/- 0.49 mm). One hundred forty-eight lesions (65.5%) were type B2 or C of AHA/ACC criteria. Follow-up angiography was performed at 3 and 6 months after the procedure. Procedural success was achieved in 96.9% of patients. The mean burr-to-artery ratio was 0.74 +/- 0.17. Adjunctive BA and stent implantation were needed in 94.2% and 22.6% of lesions, respectively. Minimal lumen diameter (MLD) increased from 0.66 +/- 0.35 mm to 1.97 +/- 0.58 mm (P < 0.01). Angiographic complications consisted of acute reclosure (3.5%), no reflow/slow flow (12.4%), and coronary artery perforation (1.8%). No death, Q-wave myocardial infarction (MI), or coronary artery bypass graft (CABG) occurred during the initial hospitalization. Restenosis rates at 3 and 6 months were 40.6% and 44.2%, respectively, and target lesion revascularization (TLR) rates were 28.5% and 33.0%, respectively. Restenosis and TLR rates during follow-up were comparable among patients who underwent RA + adjunctive BA versus patients who underwent RA + stenting. Long-term clinical follow-up was complete in 143 patients over a mean period of 348 +/- 166 days. The survival free from cardiac death, MI, CABG or repeated BA was 59.6% at 1 year. In conclusion, RA of SCA has relatively high restenosis rates, but may be appropriate for more complex, calcified lesions unsuitable for other devices.

Estimation of the supplementary axial wall stress generated at peak flow by an arterial stenosis

Mechanical stresses in arterial walls are known to be implicated in the development of atherosclerosis. While shear stress and circumferential stress have received a lot of attention, axial stress has not. Yet, stenoses can be intuitively expected to produce a supplementary axial stress during flow systole in the region immediately proximal to the constriction cone. In this paper, a model for the estimation of this effect is presented, and ten numerical examples are computed. These examples show that the cyclic increase in axial stress can be quite considerable in severe stenoses (typically 120% or more of the normal stress value). This result is in best agreement with the known mechanical or morphological risk factors of stenosis progression and restenosis (hypertension, elevated pulse pressure, degree of stenosis, stenosis geometry, residual stenosis, etc). The supplementary axial stress generated by a stenosis might create the damages in the endothelium and in the elastic membranes which potentiate the action of the other risk factors (hyperlipidaemia, diabetes, etc). It could thus be an important cause of stenosis progression and of restenosis.

Early experience with a novel plaque excision system for the treatment of complex coronary lesions

The use of directional coronary atherectomy (DCA) in current practice has been limited. The SilverHawk System is a newly developed plaque excision device that aims to overcome the drawbacks of prior DCA platforms. The device was evaluated in a porcine coronary model and in a series of patients. Procedural variables along with outcomes were reviewed. Quantitative angiography (QCA) was performed and excised tissue fragments were weighed and examined histologically. In porcine cases, pretreatment MLD increased from 0.51 +/- 0.26 to 2.36 +/- 0.59 mm postdebulking and 19.9 +/- 7.6 mg of tissue was retrieved. In human cases, pretreatment MLD increased from 0.8 +/- 0.4 to 2.2 +/- 0.5 mm postdebulking and 15.2 +/- 7.8 mg of tissue was retrieved without complications. These data show that the SilverHawk System may offer significant utility in treating a wide variety of complex coronary lesions.

Debulking and stenting versus debulking only of coronary artery disease in patients treated with cilostazol (final results of ESPRIT)

Stenting inhibits vascular constrictive remodeling after directional coronary atherectomy (DCA). Cilostazol has been reported to control neointimal proliferation after stenting. This study's aim was to examine the effect of debulking and stenting with antirestenotic medication on restenosis. After optimal DCA, 117 lesions were randomly assigned to either the DCA with stent (DCA-stent) (58 lesions) group or the DCA only (59 lesions) group. Multilink stents were implanted in the DCA-stent group. Cilostazol (200 mg/day) without aspirin was administered to both groups for 6 months. Ticlopidine (200 mg/day) was given to the DCA-stent group for 1 month. Serial quantitative angiography and intravascular ultrasound (IVUS) were performed at the time of the procedure and at 6-month follow-up. The primary end point was 6-month angiographic restenosis. Clinical event rates at 1 year were also assessed. Baseline characteristics were similar. All procedures were successful. No adverse effects to cilostazol were observed. Postprocedural lumen diameter was significantly larger (3.27 vs 2.92 mm; p <0.0001) in the DCA-stent group. However, the follow-up lumen diameter was not significantly different (2.53 vs 2.41 mm, DCA-stent vs DCA). IVUS revealed that intimal proliferation was significantly larger in the DCA-stent group (4.2 vs 1.5 mm(2); p <0.0001), which accounted for the similar follow-up lumen area (6.5 vs 7.1 mm(2)). The restenosis rate was low in both groups (5.4% vs 8.9%), and the difference was not significant. Clinical event rates at 1 year were also not significantly different. These results suggest that optimal lesion debulking by DCA does not always need adjunctive stenting if cilostazol is administered.

Effective plaque removal with a new 8 French-compatible atherectomy catheter

The purpose of this study was to evaluate the safety and efficacy of the new 8 Fr guide catheter-compatible Flexicut directional atherectomy device and to compare it with the conventional Atherocath GTO catheter. The 6 Fr Flexicut catheter has a larger cutting window and a titanium nitride-coated cutter to effect more tissue removal as well as treat mildly calcified lesions. A group of 143 lesions in 117 consecutive patients treated with the Flexicut catheter in four centers were compared with a control group of 277 lesions in 212 consecutive patients treated with the GTO device. Postatherectomy luminal diameters were larger (2.92 +/- 0.79 vs. 2.52 +/- 0.64 mm; P < 0.0001), with more luminal gain (relative gain: 0.58 +/- 0.24 vs. 0.48 +/- 0.25; P = 0.0007) using fewer directional coronary atherectomy (DCA) cuts (12 +/- 7 vs. 16 +/- 9; P = 0.0001) in the Flexicut group. A residual diameter stenosis < 20% immediately after DCA was obtained in 77% of the lesions in the Flexicut group vs. 45% in the GTO group (P < 0.0001). Histology in the former group revealed large calcium speckles in the retrieved specimens. In the Flexicut group, there was a lower incidence of access site complications and damage to the coronary ostium (2.5% vs. 7.5%; P = 0.08). The new Flexicut catheter is more effective than the conventional GTO catheter with a trend for reduced guiding catheter-related complications.

Scholarly review of geometry and compliance: biomechanical perspectives on vascular injury and healing

Mechanical stress and strain upon cardiovascular tissue are important factors that influence the ultimate configuration of clinically observed disease entities. Although mechanical forces can stimulate cellular changes and response, structural or geometric alterations introduced by disease processes can, in turn, influence local hemodynamic conditions. Dynamic interactions of structural parameters, such as arterial compliance and geometry, can further contribute to the final determination of the mechanical conditions and outcome of the vessel. Manipulation of vascular compliance and geometry may, therefore, have desirable effects. In this article, fundamental vascular biomechanical forces are defined and their association with cellular response and clinical disease processes are introduced. The interplay between vascular geometry and compliance is emphasized, and the potential for mechanical solutions to vascular diseases are explored.

Mechanisms of acute gain and late lumen loss after atherectomy in different preintervention arterial remodeling patterns

The main mechanism of restenosis after directional coronary atherectomy (DCA) remains obscure. We investigated mechanisms of restenosis after DCA in different coronary artery remodeling patterns. DCA was performed in 51 de novo lesions. The lesions were evaluated by intravascular ultrasound (IVUS) before, immediately after, and 6 months after the procedure. According to the IVUS findings before DCA, we classified the lesions into the following 3 groups: (1) positive (n = 10), (2) intermediate (n = 25), and (3) negative (n = 16) remodeling. We measured lumen area, vessel area, and plaque area using IVUS before DCA, immediately after DCA, and at follow-up. Lumen area increase after DCA was mainly due to plaque area reduction in the positive and intermediate remodeling groups (90 plus minus 15% and 80 plus minus 25% increase in lumen area, respectively), whereas that in the negative remodeling group was due to both plaque area reduction (57 plus minus 22% increase in lumen area) and vessel area enlargement (43 plus minus 33% increase in lumen area). The plaque area increase correlated strongly with late lumen area loss in the positive and intermediate remodeling groups (r = 0.884, p <0.001; r = 0.626, p <0.001, respectively), but the decrease in vessel area was not correlated with lumen area loss. In contrast, both an increase in plaque area and a decrease in vessel area were correlated with late lumen area loss (r = 0.632, p = 0.009; r = 0.515, p = 0.041) in the negative remodeling group. Coronary artery restenosis after atherectomy was primarily due to an increase in plaque in the positive and/or intermediate remodeling groups. However, in the negative remodeling group, late lumen loss might have been caused by both an increase in plaque and vessel shrinkage.