Stenting for elastic recoil during coronary angioplasty of the left main coronary artery

Intravascular imaging for left main stem assessment: An update on the most recent clinical data

Left main (LM) stem has different structural and anatomical characteristics compared to all of the other segments of the coronary tree, thus its management through percutaneous coronary intervention (PCI) is a challenge and is associated with worse clinical outcome and higher need for revascularization as compared to other lesion settings. Intravascular imaging, by means of intravascular ultrasound (IVUS) or optical coherence tomography (OCT), is an important tool for LM PCI guidance, aiming at improving the immediate performance and the long term outcome of this procedure. Following current guidelines and recent scientific findings, IVUS becomes important to firstly assess, and finally evaluate the result of LM stenting, according to the experience and preferences of the operator. The role of OCT still remains to be defined, but recent data is shedding light also on this imaging technique. The aim of this review is to highlight the latest scientific advancements regarding intravascular imaging in LM coronary artery disease.

Procedural Outcomes of Patients Undergoing Percutaneous Coronary Intervention for De Novo Lesions in the Ostial and Proximal Left Circumflex Coronary Artery

Ostial coronary artery lesions can be challenging during percutaneous coronary intervention (PCI) because of elastic fiber content, calcium burden, and angulation. We assessed procedural and clinical major adverse cardiac events (MACE) associated with PCI for ostial lesions, focusing on ostial left circumflex (LC) lesions compared with ostial left anterior descending artery (LAD) and right coronary artery lesions. All patients with ostial or very proximal coronary artery lesions treated with PCI at MedStar Washington Hospital Center (Washington, DC) from 2003 to 2018 were included. The primary end point was target lesion revascularization (TLR)-MACE, defined as the composite of all-cause mortality, Q-wave myocardial infarction (MI), and TLR at 1 year. A total of 4,759 patients with available 1-year follow-up were included: 2,236 ostial/very proximal LAD, 980 ostial/very proximal LC, and 1,543 ostial/very proximal right. The presenting clinical syndrome for the LC group was mainly stable or unstable angina, whereas MI was more common in the LAD. At 1 year, the TLR-MACE rate was 16.7% in the LC group versus 12.5% in the LAD and 11.8% in the right group (p = 0.001). Mortality rates were 11.2% in the LC group versus 8.4% in the LAD and 6% in the right group (p <0.001). A Cox model showed that dialysis had the highest impact on TLR-MACE. In conclusion, compared with PCI of ostial or very proximal LAD or right lesions, PCI of ostial or very proximal LC lesions was associated with higher rates of TLR-MACE.

Perspectives on Imaging the Left Main Coronary Artery Using Intravascular Ultrasound and Optical Coherence Tomography

Percutaneous coronary intervention (PCI) for significant left main coronary artery (LMCA) stenosis is increasingly being viewed as a viable alternative to coronary artery bypass grafting (CABG) (1). This is leading to an expectation of increasing numbers of such procedures with a consequent focus on both the ability to image lesion severity and assess more accurately the results of PCI. While there have been advances in physiological assessment of left main severity using fractional flow reserve (FFR) and in non-invasive assessment of the left main using coronary computerized tomography CT (2), imaging of the LMCA using intravascular ultrasound (IVUS) and more recently optical coherence tomography (OCT) has the specific advantage of being able to provide very detailed anatomical information both pre- and post-PCI, such that it is timely to review briefly the current status of these two imaging technologies in the context of LMCA intervention. This is presented specifically contrasting the use of these technologies both in pre-PCI lesion severity assessment, and peri-PCI procedural evaluation. Not discussed here is the separate issue of longer-term surveillance of asymptomatic patients having undergone LMCA stenting, which may appropriately be performed non-invasively using coronary CT, reviewed in detail elsewhere (2).

Stenting of left main coronary artery stenosis: A to Z

For several decades, coronary artery bypass grafting (CABG) has been considered as the gold standard treatment of unprotected left main coronary artery (LMCA) disease. The marked improvement in technique and technology makes percutaneous coronary interventions (PCIs) feasible for patients with unprotected LMCA stenosis. The recent introduction of drug-eluting stents (DESs), together with advances in periprocedural and postprocedural adjunctive pharmacotherapies, has improved outcomes of PCIs of these lesions. Recent studies comparing efficacy and safety of PCIs using drug-eluting stents and CABG revealed comparable results in terms of safety and a lower need for repeat revascularisation for CABG. Patient selection for both the techniques directly impacts clinical outcome. Despite improvement in stent technology and operator experience, management can be challenging especially in LMCA bifurcation lesions and, therefore, an integrated approach combining advanced devices, tailored techniques, adjunctive support of physiological evaluation, and adjunctive pharmacological agents should be reinforced to improve clinical outcome.

Peri-interventional coronary vasomotion

A percutaneous coronary intervention (PCI) is a unique condition to study the effects of ischemia and reperfusion in patients with severe coronary atherosclerosis when coronary vasomotor function is compromised by loss of endothelial and autoregulatory vasodilation. We studied the effects of intracoronary non-selective α-, as well as selective α(1)- and α(2)-blockade in counteracting the observed vasoconstriction in patients with stable and unstable angina and in patients with acute myocardial infarction. Coronary vasoconstriction in our studies was a diffuse phenomenon and involved not only the culprit lesion but also vessels with angiographically not visible plaques. Post-PCI vasoconstriction was reflected by increased coronary vascular resistance and associated with decreased LV-function. α (1)-Blockade with urapidil dilated epicardial coronary arteries, improved coronary flow reserve and counteracted LV dysfunction. Non-selective α-blockade with phentolamine induced epicardial and microvascular dilation, while selective α(2)-blockade with yohimbine had only minor vasodilator and functional effects. Intracoronary α-blockade also attenuated the no-reflow phenomenon following primary PCI. This article is part of a Special Issue entitled "Coronary Blood Flow".

Unprotected left main stenting, short- and long-term outcomes

BACKGROUND

Coronary bypass surgery is recommended for the treatment of left main coronary stenosis. Recently a percutaneous approach has been described as a feasible option.

OBJECTIVES

To present the in-hospital and long-term clinical and angiographic outcome of a consecutive group of patients undergoing stenting for unprotected left main coronary artery (LMCA) disease, and to compare the clinical and angiographic outcomes of drug-eluting stent (DES) versus metal stent (BMS).

METHODS

238 consecutive patients underwent unprotected LMCA stenting. 165 received BMS and 73 received DES. Most patients (88.7%) presented with acute coronary syndrome. Clinical (100%) and angiographic (84%) follow-up was obtained.

RESULTS

Patients' presentation: STEMI (7.2%), non-STEMI (13.5%), unstable angina (67.6%), stable angina (11.7%). Procedural success rate was 100%. In-hospital mortality was 2.1%, all in patients presented with unstable hemodynamic conditions. None of the patients needed emergent CABG. In the long-term follow-up (average three years) there were 12 deaths (5%), 3 patients required CABG and 25 patients required TVR. The overall angiographic LM restenosis rate show a trend toward lower rate in the DES group than the BMS group (9.6% versus 13.8%, P = 0.08). There was no difference in one year mortality (4.1% versus 4.2%) and AMI (2.7% versus 2.8%) between DES and BMS.

CONCLUSIONS

Stenting for LM stenosis can be performed safely with acceptable in hospital and long-term outcome. Reconsideration of current guidelines should be considered. Drug-eluting stent implantation for unprotected LMCA stenosis appears safe with regard to acute and long-term complications and is more effective in preventing restenosis compared to BMS implantation.

Assessing intermediate left main coronary lesions using intravascular ultrasound

BACKGROUND

Angiographic assessment of a left main coronary artery stenosis (LMCS) is often difficult and unreliable. We aimed to evaluate the severity of ambiguous LMCSs by intravascular ultrasound (IVUS) and to clarify how frequently significant stenosis occurs in the "real world".

METHODS

We retrospectively found 115 consecutive patients in our clinical IVUS database with a de novo, angiographically ambiguous, intermediate LMCS who underwent IVUS evaluation. Quantitative coronary angiography (QCA) and IVUS analyses were performed. We define a significant LMCS as a diameter stenosis >50% by QCA and a minimal lumen area <6.0 mm2 by IVUS.

RESULTS

Ostial, mid, and distal LMCSs were seen in 44 (38.3%), 6 (5.2%), and 65 (56.5%) lesions. Overall, IVUS minimal lumen area and plaque burden measured 6.8 +/- 2.6 mm2 and 63% +/- 14%. A significant LMCS was seen in 51 (44.3%) lesions by IVUS but in only 15 (13.0%) lesions by QCA. In particular, only 36.4% of ostial lesions had a significant IVUS stenosis, and minimal lumen diameter by QCA was less well correlated with IVUS in ostial lesions than in other lesion locations.

CONCLUSIONS

This real-world IVUS analysis showed that less than half of intermediate LMCSs had significant stenoses by IVUS assessment, especially for lesions located at the left main ostium. Such patients deserve IVUS assessment or physiologic assessment before blindly proceeding to revascularization.

Left main coronary artery stenosis: state-of-the-art

Patients with stenosis of the left main coronary artery present difficult challenges. The risks associated with this lesion have been known since the early days of angiography when patients were found to have increased mortality during follow-up. This information led to the general guidelines that surgical revascularization should be considered the treatment of choice in patients with significant left main coronary artery stenosis. Current advances in invasive cardiology have brought important information to the field. Intravascular ultrasound is now used routinely to evaluate angiographically indeterminate lesions with criteria now set forward as to what constitutes an indication for revascularization. Stents have even further dramatically changed the landscape. There are substantial issues, however, that need to addressed. These include the following: (1) the effect of specific lesion location on outcome - it is known that patients with distal bifurcation left main disease have worse outcome; (2) the potential for subacute thrombosis of the left main coronary artery; (3) the impact of left ventricular function and patient comorbidities irrespective of the degree and location of left main coronary artery stenosis; and (4) the risk-benefit ratio of stenting versus coronary artery bypass graft surgery. These issues are currently being addressed in two seminally important trials including the SYNTAX trial, which randomizes patients with left main and/or three-vessel disease to either coronary artery bypass graft surgery or a TAXUS drug-eluting stent. This trial is in the final stages of patient recruitment and will have important implications for the field. The other trial is the COMBAT trial, which is focused exclusively on left main coronary artery stenosis and randomizes patients with left main coronary artery disease either to a Sirolimus-eluting stent (Cypher, Johnson and Johnson Cordis, USA) or to coronary artery bypass graft surgery. The field of left main coronary artery disease continues to expand in terms of the evidence available for optimal patient evaluation and selection of treatment modalities.

Treatment of Unprotected Left Main Coronary Artery Stenosis in the Drug-Eluting Stent Era

Coronary angiography is often inadequate for estimating the severity of ambiguous left main coronary artery (LMCA) stenoses. Our assessment of these lesions can be improved by the techniques of intravascular ultrasound and fractional flow reserve which provide indices of stenosis severity to enable the prediction of future events and planning of treatment. For patients requiring LMCA revascularization, coronary artery bypass graft (CABG) surgery has been gold standard for decades. However, this technique continues to be limited by factors such as periprocedural mortality, prolonged hospital stay and rehabilitation, and long-term graft patency. LMCA stenosis remains one of the few serious challenges for the interventional cardiologists and, in the bare metal stent era, the long-term results were not sufficient to replace CABG surgery, mainly because of the high restenosis rate. Drug-eluting stents (DES) have dramatically reduced the restenosis rate and early results in small series (approximately 300 patients in total) treated with DES in LMCA have been encouraging, especially for lesions at the ostium and in the left main shaft. Before changes are made in the guidelines for treatment, we must wait for a refinement in the technique and stent design used for bifurcational left main lesion and the results of randomized, specific multicenter studies (SYNTAX trial). It is likely that, for selected patients, LMCA stenosis will be regarded as an indication for PCI.

Percutaneous intervention for unprotected left main disease prior to explantation of a left ventricular assist device

Percutaneous coronary intervention of unprotected left main coronary arterial disease is an alternative to surgical revascularization in selected patients. In this report, a patient with an implanted left ventricular assist device (LVAD) underwent successful coronary intervention prior to its planned removal. The implanted LVAD clearly assisted the technical performance of the intervention.

Technical feasibility, safety, and clinical outcome of stenting of unprotected left main coronary artery bifurcation narrowing

This study was performed to evaluate the acute and long-term results of stenting for unprotected left main coronary artery (LMCA) bifurcation lesions. Sixty-three consecutive patients with an unprotected LMCA bifurcation lesion and normal left ventricular function were included. Stenting was performed with (n = 32) or without debulking atherectomy (n = 31) at the operator's discretion. Slotted-tube stents, coil stents, or bifurcation stents were used. The procedural success rate was 100%. In-hospital events including stent thrombosis, Q-wave myocardial infarction, and emergency bypass surgery did not occur in any patients. The angiographic follow-up rate was 86% (43 of the 50 eligible patients), and the restenosis rate was 28% (parent vessel only 14%, side branch only 9%, and both 5%). Restenosis at the parent vessel occurred less frequently in the debulking group than in the nondebulking group (5% vs 33%, respectively, p = 0.02). In multivariate analysis, the debulking procedure was an independent predictive factor of restenosis for the parent vessel (odds ratio 0.10, 95% confidence intervals 0.01 to 0.91, p = 0.04). Clinical follow-up was obtained in all patients at 19.9 +/- 13.7 months. There were 2 deaths (noncardiac origin), but no myocardial infarction during follow-up. Target lesion revascularization was required in 6 patients. The event-free survival rate (death, nonfatal myocardial infarction, and repeat revascularization) was 86% at the end of the follow-up period. In conclusion, stenting for an unprotected LMCA bifurcation lesion may be performed with a high procedural success rate and a favorable clinical outcome in selected patients with normal left ventricular function, suggesting that stenting would be an effective alternative to surgery in these patients.

Long-term clinical outcomes after unprotected left main trunk percutaneous revascularization in 279 patients

BACKGROUND

Percutaneous coronary revascularization (PCI) has been increasingly applied to unprotected left main trunk (LMT) lesions, with varied long-term success. This study attempts to define the predictors of outcome in this population.

METHODS AND RESULTS

Two hundred seventy-nine consecutive patients who had LMT PCI at 1 of 25 sites between 1993 and 1998 were studied. Forty-six percent of these patients were deemed inoperable or at high surgical risk. Thirty-eight patients (13.7%) died in hospital, and the rest were followed up for a mean of 19 months. The 1-year incidence was 24.2% for all-cause mortality, 20.2% for cardiac mortality, 9.8% for myocardial infarction, and 9.4% for CABG. Independent correlates of all-cause mortality were left ventricular ejection fraction </=30%, mitral regurgitation grade 3 or 4, presentation with myocardial infarction and shock, creatinine >/=2.0 mg/dL, and severe lesion calcification. For the 32% of patients <65 years old with left ventricular ejection fraction >30% and without shock, the prevalence of these adverse risk factors was low. No periprocedural deaths were observed in this low-risk subset, and the 1-year mortality was only 3.4%.

CONCLUSIONS

Patients undergoing unprotected LMT PCI have frequent serious comorbidities and consequently have high event rates. PCI may be an alternative to CABG for a select proportion of elective patients and may also be appropriate for highly symptomatic inoperable patients. Meticulous follow-up of hospital survivors is required because of the rather high mortality during the first few months after treatment.

Elective stenting of unprotected left main coronary artery stenosis: effect of debulking before stenting and intravascular ultrasound guidance

OBJECTIVES

We sought to evaluate: 1) the long-term outcomes of 127 selected patients receiving unprotected left main coronary artery (LMCA) stenting; and 2) the impact of the debulking procedure before stenting and intravascular ultrasound (IVUS) guidance on their clinical outcomes.

BACKGROUND

The long-term safety of stenting of unprotected LMCA stenoses has not been established yet.

METHODS

A total of 127 consecutive patients with unprotected LMCA stenosis and normal left ventricular function were treated by elective stenting. The long-term outcomes were evaluated between two groups: IVUS guidance (n = 77) vs. angiographic guidance (n = 50); and debulking plus stenting (debulking/stenting; n = 40) vs. stenting only (n = 87).

RESULTS

Angiographic restenosis was documented in 19 (19%) of 100 patients. The lumen diameter after stenting was significantly larger in IVUS-guided group (p = 0.003). The angiographic restenosis rate was significantly lower in the debulking/stenting group (8.3% vs. 25%, p = 0.034). The reference artery size was the only independent predictor of angiographic restenosis. During follow-up (25.5 +/- 16.7 months), there were four deaths, but no nonfatal myocardial infarctions occurred. The survival rate was 97.0 +/- 1.7% at two years.

CONCLUSIONS

These data suggest that stenting of unprotected LMCA stenosis might be associated with a favorable long-term outcome in selected patients. Guidance with IVUS may optimize the immediate results, and debulking before stenting seems to be effective in reducing the restenosis rate. However, we need a large-scale, randomized study.

Intravascular ultrasound assessment of the stenoses location and morphology in the left main coronary artery in relation to anatomic left main length

Eighty-seven left main stenoses were evaluated by angiography and intravascular ultrasound. Intravascular ultrasound analysis included left main length (bifurcation to ostium), stenosis location, stenosis length, stenosis external elastic membrane, lumen, plaque & media cross-sectional area (CSA), plaque burden (plaque & media/external elastic membrane CSA), calcium arc, calcium length, eccentricity, and remodeling index (stenosis/reference external elastic membrane CSA). Long anatomic left main arteries (length > or =10 mm, n = 43) were compared with short anatomic left main arteries (length <10 mm, n = 44) regarding stenosis location. Ostial (proximal third of left main artery) (n = 32) and nonostial (midthird and distal third) stenoses (n = 55) were compared regarding stenosis morphology. Short anatomic left main arteries developed stenoses more frequently near the ostium (ostium 55%, bifurcation 38%). Conversely, long anatomic left main arteries developed stenoses more frequently near the bifurcation (ostium 18%, bifurcation 77%, p = 0.001). Ostial left main stenoses were more common in women (44% vs 20%, p = 0.02), had larger lumen area (6.2 +/- 2.2 vs 4.6 +/- 2.3 mm(2), p = 0.002), less plaque burden (62 +/- 15% vs 80 +/- 9%, p <0.0001), less calcification (arc = 78 +/- 65 degrees vs 195 +/- 101 degrees, p <0.0001), and more negative remodeling (remodeling index = 0.87 +/- 0.19 vs 1.01 +/- 0.21, p = 0.005) than nonostial left main stenoses. Most ostial left main stenoses were categorized as eccentric (97% vs 76%, p = 0.01). Short and long left main arteries develop stenoses at different locations. Stenosis morphology was significantly different in these 2 locations.

Unprotected left main coronary artery stenting: correlates of midterm survival and impact of patient selection

BACKGROUND

The study served to present the in-hospital and six-month clinical outcome and also the long-term survival data of a consecutive series of patients undergoing stenting for unprotected left main coronary artery (LMCA) disease.

METHODS

Revascularization with coronary bypass surgery has been generally recommended for treatment of left main coronary stenosis. Improvements in angioplasty and coronary stent techniques and equipment may result in the wider applicability of a percutaneous approach. A total of 92 consecutive patients underwent unprotected LMCA stenting between March 1994 and December 1998. For the initial 39 patients (group I) angioplasty was performed only when surgical revascularization was contraindicated. The remaining 53 patients (group II) also included patients in whom surgery was feasible. Patients were followed for 7.3 +/- 5.8 months (median 239 days; range 49 to 1,477 days).

RESULTS

Compared to group I, group II patients had higher left ventricular ejection fraction (60 +/- 12% vs. 51 +/- 16%, p < 0.01), less severe LMCA stenosis (68 +/- 12% vs. 80 +/- 10%, p < 0.001), lower surgical risk score (13 +/- 7 vs. 20 +/- 7, p < 0.001), and had angioplasty more often performed via the radial approach (88% vs. 23%, p < 0.001) with smaller guiding catheters (6F: 49% vs. 15%; 8F: 2% vs. 77%, p < 0.001). The procedural success rate was 100%. In-hospital mortality was 4% (4 deaths, 3 cardiac). During follow-up there were six deaths, 13 patients required repeat percutaneous transluminal coronary angioplasty (4 LMCA), and two required coronary artery bypass graft surgery. Estimated survival (+/- SEE) was 89 +/- 6.3% at 500 days and 85 +/- 12% at 1,000 days post-stenting. Overall mortality was 3.8% in group II and 20.5% in group I (p < 0.02).

CONCLUSIONS

Coronary stenting can be performed safely in high-risk individuals with acceptable intermediate-term outcome. It may be feasible to broaden the application of this technique in selected patients needing revascularization for left main coronary disease.

Does unprotected left main-stem stenting have a role in current interventional practice?

Left main-stem disease is found in up to 5% of patients undergoing coronary angiography. Until recently, it has been regarded as an absolute indication for coronary bypass surgery, given the poor results of the early trials of balloon angioplasty for this condition. However, with rapidly advancing technology, including new generation stents and increasingly effective post-stenting anti-thrombotic regimens, there is now an increasing body of evidence to support the consideration of a percutaneous approach to left main-stem disease. Discerning patient selection, meticulous stent sizing and deployment, the routine use of intravascular ultrasound, aggressive anti-platelet regimes, and careful patient follow up are a few of the technical considerations required for a successful long-term outcome in this group.

Factors predicting mortality in patients after myocardial infarction caused by left main coronary artery occlusion: significance of ST segment elevation in both aVR and aVL leads

Acute left main coronary artery obstruction is rare and most patients in this clinical setting die of sudden death or cardiogenic shock. During the past 8 years, we encountered 13 patients with acute myocardial infarction caused by total occlusion of the left main coronary artery (LMCA-AMI). Thus, we surveyed these patients, and attempted to elucidate helpful predictors related to the prognosis. Six of 13 patients with LMCA-AMI survived. Successful left coronary artery dilatation was achieved in all survivors (group S), and in 5 (71%) non-survivors (group non-S). The age was not different between the two groups. A past history of angina was confirmed in 83% of group S. while only in 29% of group non-S. Clinical findings such as time of onset of AMI, interval from the AMI onset to admission, elapsed period from the AMI onset to recanalization of LMCA and the value of CK on admission were not different between the two groups. However, cardiogenic shock occurred in only 1 patient (17%) in group S compared with 5 patients (71%) in group non-S. As emphasized in the literature, good collateral circulation to the left anterior descending artery was observed in 5 patients (83%) in group S, while not observed in group non-S. Electro cardiographically, ST elevation in the aVR lead was very characteristic. This finding was confirmed in 69% of the total patients. Noticeably, 5 out of 6 non-survivors (83%) showed ST elevation not only in leads aVR but also in the aVL lead. In addition to the absence of collateral circulation, this electrocardiographic finding, which obviously indicates the presence of extensive myocardial ischemia in the diseased heart, is a simple and important predictor suggesting a poor prognosis in LMCA-AMI patients.

Unprotected left main coronary artery stenting: immediate and medium-term outcomes of 140 elective procedures

OBJECTIVES

We sought to evaluate immediate and late outcomes after stenting for left main coronary artery (LMCA) stenosis.

BACKGROUND

Conventional percutaneous transluminal coronary angioplasty (PTCA), for which coronary artery bypass grafting (CABG) has been the gold standard therapy for years, has yielded poor results in unprotected LMCA lesions. The development of coronary stents, together with their dramatic patency improvement provided by new antiplatelet regimens and their validation against restenosis, warrants a reappraisal of angioplasty in LMCA stenosis.

METHODS

From January 1993 to September 1998, 140 consecutive unselected patients with unprotected LMCA stenosis underwent elective stenting. Group I included 47 high-CABG-risk patients, and group II included 93 low-CABG-risk patients. Ticlopidine without aspirin was routinely started at least 72 h before the procedure and continued for one month. Patients were reevaluated monthly. A follow-up angiography was requested after six months.

RESULTS

The procedure success rate was 100%. One-month mortality was 9% (4/47) in group I and 0% in group II. A follow-up angiography was obtained in 82% of cases, and target lesion revascularization was required in 17.4%. One-year actuarial survival was 89% in the first 29 group I patients and 97.5% in the first 63 group II patients.

CONCLUSIONS

Stenting of unprotected LMCA stenosis provided excellent immediate results, particularly in good CABG candidates. Medium-term results were good, with a restenosis rate of 23%, similar to that seen after stenting at other coronary sites. Stenting deserves to be considered a safe and effective alternative to CABG in institutions performing large numbers of PTCAs.

A prospective study of elective stenting in unprotected left main coronary disease

The standard treatment of left main coronary artery (LMCA) disease has been bypass surgery (CABG). Recent reports suggested that stenting of LMCA disease might be feasible. From January 1995 to April 1998, we carried out a prospective study of elective stenting of unprotected LMCA disease to evaluate its immediate and long-term results. Of 61 consecutive patients with unprotected LMCA disease, 6 were excluded. Acute procedural success was 100% for the remaining 55 patients, without any complications such as stent thrombosis, myocardial infarction, CABG, or death. During a mean follow-up of 16.1+/-9.6 months, 11 patients (20%) had symptomatic recurrence, between 2 to 6 months after their procedure. Seven patients underwent CABG, two had repeat intervention, one continued with medical therapy, and one died before planned angiography. There was no late sudden death. Forty-four patients (80%) remained asymptomatic. We conclude that elective stenting may be a safe alternative to CABG in unprotected LMCA disease.

Immediate and long-term results of elective and emergent percutaneous interventions on protected and unprotected severely narrowed left main coronary arteries

Percutaneous revascularization of protected and unprotected left main coronary arteries is associated with acceptable immediate results, but there are significant long-term consequences, including the need for repeat percutaneous intervention (10%), myocardial infarction (7.5%), coronary artery bypass surgery (7%), and death (38%), despite the elective or emergent nature of the procedure.

Intravascular ultrasound predictors of target lesion revascularization after stenting of protected left main coronary artery stenoses

We evaluated the predictors of late clinical outcomes after stenting of protected left main coronary artery (LMCA) stenoses. Intravascular ultrasound (IVUS) guided stenting of protected LMCA stenoses was performed in 87 consecutive patients between January 1994 and December 1996. Results were evaluated using conventional (clinical, angiographic, and IVUS) methodology. Late (12 month) clinical follow-up information was obtained in all patients. Initial procedural success was achieved in 86 patients (99%). There was 1 in-hospital death (in the 1 patient with a procedural failure). There were no other in-hospital complications, including Q-wave myocardial infarction, emergency bypass surgery, or repeat coronary angioplasty. The overall target lesion revascularization (TLR) rate was 13%. Using multivariate logistic regression analysis, the only independent predictor of TLR was the postintervention lumen area by IVUS. A final lumen area > or =7.0 mm2 was obtained in 74 patients (86%); the TLR rate for these patients was 7%. This was compared with patients with a final lumen area <7.0 mm2 in whom the TLR rate was 50% (p = 0.0011). Stenting of protected LMCA stenoses is safe and effective with acceptable long-term clinical outcomes. The most important factor determining long-term success was the postintervention lumen area by IVUS.

Results of stenting of unprotected left main coronary artery stenosis in patients at high surgical risk

From March 1994 to September 1996, 39 patients underwent stenting of the unprotected left main coronary artery because of high surgical risk. Stenting appeared to improve clinical outcome, but there was a significant mortality rate at long-term follow-up.

Emergency left main stenting in the management of postcoronary bypass graft surgery (CABG) ischemia

Angioplasty has been used in the management of postcoronary bypass graft myocardial ischemia/infarction. A stent was successfully deployed in the left main artery in a patient with postcoronary bypass graft ischemia with hemodynamic instability. This case illustrates the potential use of emergency left main stenting in a selected patient with peri-operative ischemia, who was considered high risk for re-operation.

Intravascular ultrasound findings in stenting of unprotected left main coronary artery stenosis

We evaluated the role of intravascular ultrasound (IVUS) in 16 patients with unprotected left main coronary artery (LMCA) stenting compared with 80 patients with other (non-LMCA) native coronary artery stenting and found that (1) additional high-pressure or larger size balloon dilations were more frequently performed in LMCA stenting than in non-LMCA stenting (p <0.05) and (2) after IVUS-guided stent implantation, minimum lumen area was > or = 9 mm2 in 88% of patients who underwent LMCA stenting and in 19% of those who underwent non-LMCA stenting (p <0.001). IVUS guidance may be a more important adjunctive imaging modality in the stenting of unprotected LMCA stenoses than in stenting of non-LMCA stenoses.

Stenting of "unprotected" left main coronary artery stenoses: early and late results

OBJECTIVE

To assess short and long term efficacy of coronary stent implantation for unprotected left main coronary artery stenosis.

DESIGN

Retrospective follow up study.

SETTING

Tertiary referral centre for interventional cardiology and cardiac surgery.

PATIENTS

Eighteen consecutive patients (12 men; age 70.8 years) between May 1993 and July 1996. Ten patients presented with stable angina and underwent the procedure electively, eight patients presented either with unstable angina or myocardial infarction and underwent the procedure in emergency.

INTERVENTION

Johnson and Johnson Palmaz-Schatz stents were used in 16 patients, and a Microstent and a Gianturco-Roubin in one patient each. An intra-aortic balloon pump was prophylactively used for two patients in the elective group. In the acute group, six required an intra-aortic balloon pump.

MAIN OUTCOME MEASURES

Procedural success rate and major adverse cardiac events.

RESULTS

Successful stent implantation was achieved in all patients. In the elective group, no major adverse cardiac event occurred during the procedure, but one patient had to undergo repeated angioplasty before discharge. All patients of the elective group were discharged alive and there has been one non-cardiac death during a follow up of (mean (SD)) 10 (4) months. In the emergency group, one patient died during the procedure, one patient developed a non Q-wave myocardial infarction, one patient underwent emergency coronary bypass surgery, while another patient died suddenly before hospital discharge. Six patients of the emergency group were discharged alive and there has been one non-cardiac death during a follow up of 7 (4) months.

CONCLUSIONS

Elective stent implantation for unprotected left main coronary artery stenosis is safe and effective in selected stable patients. Urgent stent implantation, however, cannot be considered as a definitive procedure in emergency situation.

Stenting of unprotected left main coronary artery stenoses: immediate and late outcomes

OBJECTIVES

We examined the immediate and long-term outcomes after stenting of unprotected left main coronary artery (LMCA) stenoses in patients with normal left ventricular (LV) function.

BACKGROUND

Left main coronary artery disease is regarded as an absolute contraindication for coronary angioplasty. Recently, several reports on protected or unprotected LMCA stenting, or both, suggested the possibility of percutaneous intervention for this prohibited area.

METHODS

Forty-two consecutive patients with unprotected LMCA stenoses and normal LV function were treated with stents. The post-stent antithrombotic regimens were aspirin and ticlopidine; 14 patients also received warfarin. Patients were followed very closely with monthly telephone interviews and follow-up angiography at 6 months.

RESULTS

The procedural success rate was 100%, with no episodes of subacute thrombosis regardless of anticoagulation regimen. Six-month follow-up angiography was performed in 32 of 34 eligible patients. Angiographic restenosis occurred in seven patients (22%, 95% confidence interval 7% to 37%); five patients subsequently underwent elective coronary artery bypass graft surgery (CABG), and two patients were treated with rotational atherectomy plus adjunct balloon angioplasty. The only death occurred 2 days after elective CABG for treatment of in-stent restenosis. The other patients (without angiographic follow-up) remain asymptomatic.

CONCLUSIONS

Stenting of unprotected LMCA stenoses may be a safe and effective alternative to CABG in carefully selected patients with normal LV function. Further studies in larger patient populations are needed to assess late outcome.

Contemporary percutaneous treatment of unprotected left main coronary stenoses: initial results from a multicenter registry analysis 1994-1996

BACKGROUND

Coronary artery bypass surgery (CABG) has been considered the therapy of choice for patients with unprotected left main (ULMT) coronary stenoses. Selected single-center reports suggest that the results of percutaneous intervention may now approach those of CABG.

METHODS AND RESULTS

To assess the results of percutaneous ULMT treatment from a wide variety of experienced interventional centers, we requested data on consecutive patients treated after January 1, 1994, from 25 centers. One hundred seven patients were identified who were treated either electively (n=91) or for acute myocardial infarction (n=16). Of patients treated electively, 25% were considered inoperable, and 27% were considered high risk for bypass surgery. Primary treatment included stents (50%), directional atherectomy (24%), and balloon angioplasty (20%). Follow-up was 98.8% complete at 15+/-8 months. Results varied considerably, depending on presentation and treatment. For patients with acute myocardial infarction, technical success was achieved in 75%, and survival to hospital discharge was 31%. For elective patients, technical success was achieved in 98.9%, and in-hospital survival was strongly correlated with left ventricular ejection fraction (P=.003). Longer-term event (death, infarction, or bypass surgery) -free survival was correlated with ejection fraction (P<.001) and was inversely related to presentation with progressive or rest angina (P<.001). Surgical candidates with ejection fractions > or = 40% had an in-hospital survival of 98% and a 9-month event-free survival of 86+/-5%, whereas patients with ejection fractions < 40% had 67% and 22+/-12% in-hospital and 9-month event-free survivals, respectively. Nine hospital survivors (10.6%) experienced cardiac death within 6 months of hospital discharge.

CONCLUSIONS

While results for selected patients appear promising, until early post-hospital discharge cardiac death can be better understood and minimized, percutaneous revascularization of ULMT stenosis should not be considered an alternative to bypass surgery for most patients. When percutaneous revascularization of ULMT is required, directional atherectomy and stenting appear to be the preferred techniques, and follow-up angiography 6 to 8 weeks after treatment is probably advisable.

Left main intervention revisited: early and late outcome of PTCA and stenting

We reviewed our experience with 28 unselected, consecutive patients undergoing left main coronary artery (LMCA) angioplasty who had been considered unsuitable for coronary artery bypass graft surgery (CABG). Fourteen patients (50%) had a protected LMCA circulation. Balloon angioplasty was performed in 11 patients (39.3%), and stents were implanted in 17 patients (60.7%). The procedure was elective in 22 patients (78.6%) and acute in the setting of myocardial infarction/cardiogenic shock in 6 (21.4%). The mean follow-up duration was 15.9 +/- 12 months. There were 5 early (before hospital discharge) and 4 late deaths (total 32.1%), 1 myocardial infarction (3.6%), 6 repeat angioplasties (21.4%), and 3 subsequent CABG (10.7%). All 5 early deaths occurred in patients with cardiogenic shock and unprotected circulation. The results of our study suggest that when patients have prohibitive surgical risks, elective LMCA angioplasty and/or stenting may be undertaken with a high procedural success rate. However, our data do not support intervention in the presence of acute myocardial infarction/cardiogenic shock.

Percutaneous treatment of protected and unprotected left main coronary stenoses with new devices: immediate angiographic results and intermediate-term follow-up

OBJECTIVES

We sought to evaluate the immediate angiographic results and intermediate-term follow-up after percutaneous treatment of left main coronary stenoses in the new device era.

BACKGROUND

Historically, balloon angioplasty of left main coronary stenoses has been associated with high procedural morbidity and poor long-term results. It is not clear whether new devices are more effective in this anatomic setting.

METHODS

Between July 1993 and July 1995, we performed initial left main coronary interventions on 46 patients (mean age 67 +/- 12 years, 26% women). Quantitative angiography was available for 42 of 46 interventions, and clinical follow-up was obtained for all patients at 1 month, 6 months and 1 year after initial revascularization.

RESULTS

Most interventions (42 of 46) were performed in patients with "protected" coronary stenoses to the left coronary system owing to the presence of one or more patent left main coronary grafts. Seventy-seven percent of screened patients were deemed unsuitable for repeat coronary artery bypass surgery. Procedures performed included stenting in 73% of patients (alone in 30% and after rotational atherectomy in 43%), rotational atherectomy in 58% (alone in 15% and before stenting in 43%), directional atherectomy in 4% and angioplasty alone in 7%. Initial procedural success was achieved in all interventions, with no deaths, myocardial infarctions (creatine kinase, MB fraction > 50 IU/liter) or emergent bypass surgery. Follow-up data to date (median duration 9 months, range 6 to 19) demonstrate a 98% overall survival rate and a 6-month event-free survival rate of 78% (six target vessel revascularizations [TVRs], four non-TVRs).

CONCLUSIONS

Treatment of protected left main coronary artery stenoses can be accomplished safely and effectively with new device technology. Intermediate-term follow-up demonstrates an acceptably low rate of death, myocardial infarction or repeat revascularization at 6 months and 1 year.

Elective stenting of unprotected left main coronary disease

For the 12-mo period of 1995, we encountered seven consecutive patients with symptomatic unprotected left main coronary stenosis requiring revascularization. There were five males and two females, age ranging 48-76 years. One patient was referred to coronary bypass surgery. Of the remaining six patients, three refused surgery and the other three, including one with previous bypass surgery and two with previous interventional procedures, preferred percutaneous revascularization. All six had successful elective stenting of their left main coronary stenoses with the new short Palmaz-Schatz stents, P084 and PS104. There were no complications and all remained totally asymptomatic at 3-14 months followup. We conclude that with proper patient selection and the availability of appropriate stents, elective stenting of unprotected left main coronary stenosis is safe with good immediate and medium term results.

Comparison of myocardial perfusion reserve before and after coronary balloon predilatation and after stent implantation in patients with postangioplasty restenosis

BACKGROUND

Stents provide a scaffold for coronary arteries after angioplasty and inhibit elastic recoil.

METHODS AND RESULTS

In 25 patients with postangioplasty restenosis of the left anterior descending artery, ECG-gated digital subtraction coronary angiograms were recorded at baseline and during hyperemia (12 mg papaverine IC) before and after balloon predilatation (PTCA), after implantation of a Palmaz-Schatz stent, and after 6 months. Densitometric evaluation revealed different time and density parameters to calculate two definitions of myocardial perfusion reserve (MPR1 and MPR2) and maximum flow ratio (MaxFR). Poststenotic MPR1 increased from 1.57 +/- 0.14 to 2.59 +/- 0.86 after PTCA and to 3.10 +/- 0.41 after stenting, with 2.90 +/- 0.65 at follow-up (ANOVA, P < .05), while reference MPR1 remained unchanged at 3.10 +/- 0.40. Poststenotic MPR2 increased from 1.36 +/- 0.28 to 2.50 +/- 1.20 and to 3.40 +/- 0.58, respectively, with 3.20 +/- 0.92 at follow-up (ANOVA, P < .05), while reference MPR2 remained unchanged at 3.40 +/- 0.60. MaxFR was 2.13 +/- 0.53 after PTCA, elasticity 2.83 +/- 0.35 after stenting, and 2.73 +/- 0.58 at follow-up (ANOVA, P < .05). A good correlation was found between minimal stenotic luminal diameter and MPR1 or MPR2 (r = .87 and r = .94) and between luminal gain and MaxFR (r = .75). A negative correlation was measured between recoil and MPR1, MPR2, and MaxFR (r = -.80, r = -.86, and r = -.83). At follow-up, a steeper correlation was found between MPR and minimal stenosis diameter (MPR1: slope, 0.52 versus 0.91; MPR2: slope, 1.48 versus 1.95) and between MaxFR and net lumen gain (slope, 0.78 versus 1.27).

CONCLUSIONS

Coronary stent implantation in patients with postangioplasty restenosis normalized poststenotic myocardial perfusion immediately as a result of a larger postprocedural lumen and a more pronounced inhibition of elastic recoil. After 6 months this benefit was sustained despite progressive lumen loss.

Treatment of unprotected left main stenoses with Palmaz-Schatz stenting

Coronary artery bypass surgery remains the standard modality for revascularization of significant left main coronary artery stenoses. Despite major improvement in equipment and operator technique, balloon angioplasty of significant unprotected left main obstruction generally is contraindicated. When catheter intervention is required, Palmaz-Schatz stenting may offer better predictability of the acute result, and possibly improved long-term outcome.

Rotablation and stent placement in an unprotected left main coronary ostial stenosis

We report the case of a patient with postinfarction rest angina, high grade ostial left main (LM) stenosis, and right and circumflex coronary occlusion. Coronary artery bypass was performed, yet all grafts failed within 2 months of surgery. We elected to proceed with coronary intervention on the ostial LM lesion with intracoronary ultrasound lesion characterization and percutaneous cardiopulmonary bypass support. Rotablation followed by stent deployment achieved a successful angiographic outcome with no associated clinical complications. At 1-year follow-up, the patient remains stable with evidence of mild restenosis. Interventional approaches in unprotected LM coronary stenoses are associated with high procedural risk. Combined atherectomy/ablation with stent placement guided by intracoronary ultrasound may enhance procedural and long-term outcome.

Stent implantation of saphenous vein graft aorto-ostial lesions in patients with unstable ischemic syndromes: immediate angiographic results and long-term clinical outcome

OBJECTIVES

This study examined the immediate angiographic and long-term clinical results of stenting saphenous vein graft aorto-ostial stenosis at a single center.

BACKGROUND

Data on the feasibility, safety and short- and long-term clinical results of stent implantation in aorto-ostial lesions in patients with unstable angina are limited.

METHODS

Palmaz or Palmaz-Schatz stents were deployed in 29 patients (mean [+/- SD] age 70 +/- 10 years) with complex (B2 or C) vein graft aorto-ostial lesion morphology. All patients had angina at rest; 23 (79%) had a previous myocardial infarction; and 13 (45%) had two previous bypass operations (mean graft age 9 +/- 5 years). Mean left ventricular ejection fraction was 42 +/- 13%.

RESULTS

Thirty-two stents were deployed in 25 new and 4 restenotic aorto-ostial lesions. Ten additional stents were implanted in five patients for eight lesions other than at ostial locations. Stent implantation was successful in all patients. There was no death, Q wave myocardial infarction, bypass surgery or stent thrombosis in the first 30 days. Stenting improved minimal lumen diameter from 0.7 +/- 0.5 mm (95% confidence interval [CI] 0.5 to 0.8) to 3.3 +/- 0.5 mm (CI 3.2 to 3.5) and percent diameter stenosis from 80 +/- 13% (CI 75% to 85%) to 1 +/- 12% (CI -3% to 6%) (p < 0.001 for both variables). Immediate loss from recoil was 0.2 +/- 0.2 mm (CI 0.2 to 0.3), corresponding to a percent recoil of 7 +/- 5% (CI 5% to 9%). Clinical follow-up in all patients at a mean of 11 +/- 8 months revealed that 27 patients (94%) were free of death or myocardial infarction. Bypass surgery and balloon angioplasty were required in one (3%) and two (6%) patients, respectively. In 21 (88%) of the remaining 24 patients, symptoms were lessened by two or more symptom classes.

CONCLUSIONS

Palmaz or Palmaz-Schatz stent implantation for saphenous vein graft aorto-ostial stenosis has a high likelihood of immediate success and is associated with a large immediate gain in lumen diameter. Thirty-day and long-term adverse event rates are low. These data suggest that stenting saphenous vein graft aorto-ostial lesions is an acceptable therapeutic option in selected elderly patients with unstable angina and large-diameter vessels.

Coronary stenting for acute coronary dissection after coronary angioplasty: implications of residual dissection

OBJECTIVES

The aim of this study was to assess the implications of residual coronary dissections after stenting.

BACKGROUND

Coronary stenting is currently used in selected patients with coronary dissection after angioplasty. However, in some patients the total length of the dissection may not be completely covered with the device.

METHODS

Forty-two consecutive patients (mean [+/- SD] age 58 +/- 11 years; 39 men, 3 women) undergoing stenting for a major coronary dissection after angioplasty were studied.

RESULTS

Thirty (67%) coronary dissections were small (< or = 15 mm), and 29 (64%) were occlusive (Thrombolysis in Myocardial Infarction [TIMI] flow grade < or = 2). In 3 patients, coronary stenting was unable to open large occlusive dissections, but a good angiographic result was obtained in 39 patients (93%). After stenting, 22 of these patients (56%) had no visible residual dissections, and 13 (33%) had small and 4 (10%) had large residual dissections. These residual dissections were stable and did not compromise coronary flow. In a repeat angiogram (24 h later) the stent was patent in all 39 patients. However, two patients experienced a subacute stent occlusion. Of the remaining 37 patients, 36 (97%) had a late angiogram after stenting. Quantitative angiography revealed a reduction in minimal lumen diameter at the stent site (2.6 +/- 0.4 vs. 2 +/- 0.7 mm, p < 0.05) and a trend toward improvement in vessel diameter at the site of the previous residual dissection (1.7 +/- 0.6 vs. 1.9 +/- 0.5 mm, p < 0.1). The angiographic image of residual dissection disappeared in all patients. These factors provided a rather smooth angiographic appearance at follow-up. The four patients with large residual dissections after stenting did not have restenosis and were asymptomatic at last visit.

CONCLUSIONS

Coronary stenting is effective in the management of acute coronary dissections after angioplasty. In this setting, small residual dissections are frequently seen but have a good outcome and disappear at follow-up. Large residual dissections may have a good outcome if coronary flow is not impaired and no residual stenosis is visualized.

Determinants of coronary compliance in patients with coronary artery disease: an intravascular ultrasound study

OBJECTIVES

The aim of this study was to elucidate determinants of coronary compliance in patients with coronary artery disease.

BACKGROUND

Intravascular ultrasound potentially enables in vivo evaluation of coronary artery compliance.

METHODS

Twenty-seven patients (mean age [+/- SD] 57 +/- 11 years, three women) undergoing coronary angioplasty were studied with intravascular ultrasound imaging. A mechanical intravascular ultrasound system (4.8F, 20 MHz) was used. A total of 58 different coronary segments (proximal to the target angiographic lesion) were studied. Of these, 35 were located in the left anterior descending, 9 in the left main, 8 in the left circumflex and 6 in the right coronary arteries. During intravascular ultrasound imaging, 22 segments (38%) appeared normal, but 36 (62%) had plaque (24 fibrotic, 3 lipidic and 9 calcified). Systolic-diastolic changes in area (delta A) and pressure (delta P) with respect to vessel area (A) were used to study normalized compliance (Normalized compliance = [delta A/A]/delta P [mm Hg-1 x 10(3)]).

RESULTS

Lumen area and plaque area were 12.6 +/- 5.7 and 3 +/- 3 min2, respectively. Plaque was concentric (more than two quadrants) at 10 sites, but the remaining 26 plaques were eccentric. Compliance was inversely related to age (r = -0.34, p < 0.05) but was not related to other clinical variables. Compliance was greater in the left main coronary artery (3.9 +/- 2.1 vs. 1.8 +/- 1.2 mm Hg-1, p < 0.05) and in coronary segments with normal findings on ultrasound imaging (2.9 +/- 1.9 vs. 1.6 +/- 1.1 mm Hg-1, p < 0.01). Moreover, at diseased coronary segments compliance was lower in calcified plaques than in other types of plaques (1.2 +/- 0.7 vs. 2.3 +/- 1.6 mm Hg-1, p < 0.01) but was similar in concentric and eccentric plaques (1.6 +/- 1.5 vs. 1.6 +/- 0.9 mm Hg-1). Plaque area (r = -0.38, p < 0.01) was inversely correlated with compliance. On multivariate analysis, only age and plaque area were independently related to compliance.

CONCLUSIONS

Intravascular ultrasound may be used to evaluate compliance in patients with coronary artery disease. Compliance is reduced with increasing age and is mainly determined by the arterial site and by the presence, size and characteristics of plaque on intravascular ultrasound imaging.

Bail-out stenting for left main coronary artery occlusion following diagnostic angiography

We report a case of acute left main coronary artery occlusion treated with stenting of the left main artery. The patient had a severe ostial left main stenosis and after diagnostic coronary angiography developed a total occlusion of the left main artery with life threatening hemodynamic consequences. Stenting of the unprotected left main coronary artery was successfully performed as a salvage procedure.

Emergency coronary stenting for acute occlusive dissection of the left main coronary artery

Catheter-induced left main coronary artery dissection is a rare but serious complication of diagnostic cardiac angiography. We report the case of a patient with mitral regurgitation and accidental dissection of the left main coronary artery successfully managed with intracoronary stent that allowed emergent surgical revascularization and mitral replacement.