Directional Coronary Atherectomy Research Articles

Influence of plaque morphology on the mechanism of luminal enlargement after directional coronary atherectomy and balloon angioplasty.

To relate the mechanism of luminal gain after directional atherectomy and balloon angioplasty to the morphological characteristics of the coronary lesions, assessed by intravascular ultrasound imaging. Intravascular ultrasound imaging was performed before and after the revascularisation procedure to assess the contribution of wall stretching and plaque reduction in luminal gain. 32 patients undergoing balloon angioplasty and 29 undergoing directional coronary atherectomy. The main luminal area in vessels treated by balloon angioplasty increased from 1.51 (SD 0.30) to 3.91 (1.09) mm2 (P < 0.0001) with a concomitant increase in total vessel area from 11.44 (2.73) to 13.07 (2.83) mm2 (P < 0.0001). Therefore stretching of the vessel wall accounted for 68% of the luminal gain while plaque reduction accounted for the remaining 32%. This mechanism ranged from 45% in non-calcific plaques to 81% in echogenic plaques. The main luminal area in vessels treated by directional atherectomy increased from 1.49 (0.32) to 4.68 (1.73) mm2 (P < 0.0001), with a concomitant increase of total vessel area from 13.61 (4.67) to 15.2 (4.04) mm2 (P = 0.006). Thus stretching of the vessel wall accounted for 49% of the luminal area gain and plaque reduction for the remaining 51%. The presence of calcium influenced the relative contribution of these two mechanisms to the final luminal gain after directional atherectomy, since in calcific plaques stretching of the vessel wall accounted for only 9% of the luminal gain as compared to 56% in non-calcific plaques. After balloon angioplasty there was greater evidence of coronary dissections (32% v 3% after directional atherectomy, P < 0.01) and plaque fissure (60% v 0%, P < 0.01). Plaque fissure was more frequently seen in echolucent and concentric lesions, whereas dissections prevailed in echogenic and eccentric lesions. Intravascular ultrasound imaging may allow the assessment of acute changes in lumen and vessel wall after revascularisation procedures, and help in evaluating the potential effect of the structure and morphology of coronary lesions on the mechanism of luminal enlargement.

Angiographic, ultrasonic, and angioscopic assessment of the coronary artery wall and lumen area configuration after directional atherectomy: The mechanism revisited

The purpose of the present study was to use the complementary information of angiography, intravascular ultrasound, and intracoronary angioscopy before and after directional atherectomy to characterize the postatherectomy appearance of vessel wall contours and the mechanism of lumen enlargement. Directional coronary atherectomy aims at debulking rather than dilating a coronary artery lesion. The selective removal of the plaque may potentially minimize the vessel wall damage and lead to subsequent better late outcome. Whether plaque removal is the main mechanism of action has only to be assessed indirectly by angiography and warrants further investigation with detailed analysis of luminal changes and vessel wall damage by ultrasound and direct visualization with angioscopy. Twenty-six patients have been investigated by quantitative angiography, intravascular ultrasound, and intracoronary angioscopy ( n = 19) before and after atherectomy. In addition, all retrieved specimens were microscopically examined. Ultrasound imaging showed an increase in lumen area from 1.95 ± 0.70 mm 2 to 7.86 ± 2.16 mm 2 at atherectomy. The achieved gain mainly resulted from plaque removal because plaque plus media area decreased from 18.16 ± 4.47 mm 2 to 13.13 ± 3.10 mm 2. Vessel wall stretching (i.e., change in external elastic lamina area) accounted for only 15% of lumen area gain. Luminal gain was higher in noncalcified (6.52 ± 2.12 mm 2) lesions than in lesions containing deeply located calcium (5.19 ± 0.99 mm 2) and lowest in superficially calcified lesions (5.41 ± 2.41 mm 2). Ultrasound imaging identified an atherectomy byte in 85% of the cases, whereas angioscopy revealed such a crevice in 74%. The complementary use of the three techniques revealed an underestimation of the presence of dissection/tear and new thrombus by angiography (10% and 4%) and ultrasound imaging (12% and 0%) compared with angioscopy (26% and 21%). The combined use of angiography, ultrasound, and angioscopy reveals that the postatherectomy luminal lining is not as regular and smooth as that seen by angiography. Luminal enlargement with atherectomy is achieved by plaque excision rather than arterial expansion.

Perforation of nontarget artery during directional coronary atherectomy

We report a case of perforation of an intermediate branch during attempted directional atherectomy of an ostial left anterior descending artery lesion, resulting from disruption of the cutter drive cable. Potential contributing factors and means of avoiding this complication are discussed.

Proteinases and restenosis in the human coronary artery: extracellular matrix production exceeds the expression of proteolytic activity

To understand the balance of proteinase antiproteinase activity and the production of extracellular matrix (ECM) at the site of arterial injury, we analyzed the composition of ECM and proteinase activity in normal internal mammary arteries, tissue samples obtained from atherosclerotic coronary lesions and restenotic lesions obtained during directional coronary atherectomy. Histologically and biochemically, collagen and proteoglycans increased, and elastin decreased in samples from restenotic lesions when compared to samples taken from patients undergoing their first revascularization (de novo). In contrast, cellularity was increased in samples obtained from de novo patients as compared to samples obtained from restenotic lesions. Intrinsic activity of matrix metalloproteinases (MMPs) was measured by using zymography and scanning all the lytic bands in zymographic gel. In these gels, identical amounts of total protein were loaded in each lane. MMP activity was determined as % of the total (latent and active) MMPs after trypsin activation (100%) in the normal artery. Intrinsic MMP activity was reduced to 6% ± 1% in atherosclerotic lesions and 1% ± 1% in restenotic lesions, when compared to activity found in normal (10% ± 3%) arteries. Based on solubilization of fluorescein-conjugated elastin by the extracts, the MMP-mediated elastinolytic activity was 0.2 ± 0.1, 8.8 ± 1.5, and 24.0 ± 3 nmol/min/mg in restenotic, native atherosclerotic and normal tissue, respectively. The results suggested that, in arterial tissue from patients with angiographic restenosis, there is an increased production of ECM collagen and a decrease in MMP activity compared to both normal artery and atherosclerotic samples from de novo patients undergoing an initial revascularization procedure of a significant coronary artery lesion.

Atherectomy (directional, rotational, extractional) and its role in percutaneous revascularization

After an initial wave of enthusiasm, atherectomy devices face a number of difficult issues today. The first two randomized studies comparing balloon angioplasty with directional atherectomy, the Coronary Angioplasty Versus Excisional Atherectomy Trial (CAVEAT) and the Canadian Coronary Atherectomy Trial (CCAT), showed no clinical benefit for atherectomy. Data from these trials, as well as other studies, suggest that the mechanism of lumen enlargement with atherectomy may be less beneficial than expected. A number of investigations are currently evaluating the benefit of even more aggressive debulking with directional coronary atherectomy, but in view of the increased incidence of acute complications, it is unlikely that this technique will increase its share in routine coronary angioplasty in the near future. Clinical evaluation of rotational and extractional atherectomy has not reached a conclusive phase yet, but results from registries and single-center observations show that these devices require adjunctive balloon angioplasty in a large proportion of cases, on the one hand, and that they do not solve the issue of restenosis, on the other. The difficulty in delineating the rationale for use of these devices highlights the urgent need for controlled and carefully designed device trials.

Coronary angioplasty, atherectomy and bypass surgery in cardiac transplant recipients

This study sought to analyze the outcomes of revascularization procedures in the treatment of allograft coronary disease. Allograft vasculopathy is the main factor limiting survival of heart transplant recipients. Because no medical therapy prevents allograft atherosclerosis, and retransplantation is associated with suboptimal allograft survival, palliative coronary revascularization has been attempted. Thirteen medical centers retrospectively analyzed their complete experience with percutaneous transluminal coronary angioplasty, directional coronary atherectomy and coronary bypass graft surgery in allograft coronary disease. Sixty-six patients underwent coronary angioplasty. Angiographic success (< or = 50% residual stenosis) occurred in 153 (94%) of 162 lesions. Forty patients (61%) are alive without retransplantation at 19 +/- 14 (mean +/- SD) months after angioplasty. The consequences of failed revascularization were severe. Two patients sustained periprocedural myocardial infarction and died. Angiographic restenosis occurred in 42 (55%) of 76 lesions at 8 +/- 5 months after angioplasty. Angiographic distal arteriopathy adversely affected allograft survival. Eleven patients underwent directional coronary atherectomy. Angiographic success occurred in 9 (82%) of 11 lesions. Two periprocedural deaths occurred. Nine patients are alive without transplantation at 7 +/- 4 months after atherectomy. Bypass graft surgery was performed in 12 patients. Four patients died perioperatively. Seven patients are alive without retransplantation at 9 +/- 7 months after operation. Coronary revascularization may be an effective palliative therapy in suitable cardiac transplant recipients. Angioplasty has an acceptable survival in patients without angiographic distal arteriopathy. Because few patients underwent atherectomy and coronary bypass surgery, assessment of these procedures is limited. Angiographic distal arteriopathy is associated with decreased allograft survival in patients requiring revascularization.

Separation of a flexible nose cone tip during directional atherectomy

An 82-yr-old white female underwent directional coronary atherectomy of a high-grade proximal left anterior artery stenosis. The nose cone tip of a Simpson Atherocath SCA-EX separated during loading of the device onto a 360-cm exchange wire. This was recognized prior to insertion through a rotating hemostatic valve and exchanged for another device. Catheterization laboratory policy regarding defective devices is briefly discussed.

The Role of the Perfusion Balloon Catheter After an Initially Unsuccessful Coronary Intervention

Major dissection and acute closure following conventional percutaneous transluminal coronary angioplasty (PTCA) occur in 5%-10% of cases and lead to significant morbidity. Newer percutaneous modalities such as directional coronary atherectomy (DCA), excimer laser coronary angioplasty (ELCA), rotational ablation, and transluminal extraction atherectomy (TEC) can also be complicated by dissection and acute closure. Redilatation with conventional balloon catheters can reestablish patency of the artery or improve flow in a minority of cases. The perfusion balloon catheter (PBC) has several advantages over conventional balloon angioplasty in this situation. In approximately 70% of these cases, subsequent use of a PBC yields an acceptable clinical and angiographic result. The PBC permits rapid resolution of ischemia caused by acute closure or a flow-limiting dissection. New modifications of the PBC make it possible to position the catheter in nearly all segments of the coronary arterial tree including locations not accessible to other modalities, such as coronary stents or DCA, that are also used for salvage after a failed coronary intervention. Even if the PBC does not yield a definitive result, it allows rapid restoration of antegrade flow prior to coronary artery bypass grafting or coronary stent placement. Because of its ease of use, wide applicability, and efficacy, the PBC should be considered as the initial means of treatment in cases of major dissection or acute closure following any modality of percutaneous coronary revascularization.

Long-term Outcome of Transient, Uncomplicated In-Laboratory Coronary Artery Closure

Successful reversal of abrupt vessel closure without resultant major ischemic complications (death, Q-wave myocardial infarction, or coronary artery bypass graft surgery) is achieved in nearly half of all cases of abrupt vessel closure. The long-term outcome of these patients has not been previously addressed, and it is not clear whether they have a different prognosis than that of patients who have a successful procedure not associated with transient vessel closure. We examined 4863 consecutive patients who underwent successful percutaneous transluminal coronary angioplasty (PTCA) or directional coronary atherectomy (DCA). Eighty-eight patients had an uncomplicated, successfully reversed transient in-laboratory vessel closure (group 2) and were compared with 4775 patients who had a successful procedure not associated with transient in-laboratory closure (group 1). Clinical follow-up was available in 4839 patients (99.5%), with a mean duration of 41 +/- 23 months (range, 1 to 104 months). Survival analysis showed that successfully treated, uncomplicated transient vessel closure per se does not have an adverse effect on long-term prognosis (death, myocardial infarction, or coronary interventions). However, when the procedure (PTCA or DCA) was associated with an increase in creatine kinase-MB (CK-MB), there was a significant adverse effect on long-term outcome. By multivariate logistic regression, an increase in postprocedure CK-MB was the most significant correlate for cardiac death (risk ratio, 1.25; P < .0001). An increase in CK-MB was also the most important correlate for major ischemic complications (death, infarction, or coronary interventions) on follow-up (risk ratio, 1.08; P = .0005). Transient, uncomplicated in-laboratory vessel closure per se does not have an adverse long-term effect. However, a concomitant elevation of postprocedure cardiac enzymes has an important and significant adverse effect on long-term outcome. This study suggests that periprocedural creatine kinase isoenzyme determination in patients experiencing in-laboratory coronary closure has important prognostic implications.

Does hypotension during dobutamine stress echocardiography correlate with anatomic or functional cardiac impairment?

The development of hypotension during various exercise stress tests has been correlated with the presence of multivessel coronary artery disease and impaired left ventricular contractility. Hypotension may also occur during dobutamine stress echocardiography; however, its anatomic and functional significance remains unknown. As part of an ongoing study of restenosis, dobutamine stress echocardiography and diagnostic cardiac catheterization were performed on the same day in 105 outpatients approximately 6 months after percutaneous coronary revascularization (balloon angioplasty or directional coronary atherectomy) to determine the anatomic and functional significance of dobutamine-induced hypotension. Dobutamine was infused in stepwise increments to a maximum rate of 30 μg/kg/min. Hypotension was defined as a reduction in systolic blood pressure of ≥ 15 mm Hg. Anatomic abnormalities were defined by quantitative coronary angiography and functional abnormalities by digitized two-dimensional stress echocardiography. Clinical, angiographic, hemodynamic, and electrocardiographic data underwent multivariable regression analysis to determine their ability to predict independently the development of dobutamine-induced hypotension. Dobutamine-induced hypotension was not associated with the presence or severity of coronary artery disease or with echocardiographic wall motion abnormalities. Univariable predictors of stress-induced hypotension included high baseline systolic blood pressure, advanced age, and high left ventricular ejection fraction. Only a high baseline systolic blood pressure contributed independent predictive information in multivariable stepwise logistic regression analysis. Therefore, the development of hypotension during dobutamine stress echocardiography, unlike that during traditional exercise stress tests, is not associated with the presence of significant coronary artery disease or left ventricular dysfunction.

Characteristics and consequences of myocardial infarction after percutaneous coronary intervention: Insights from the coronary angioplasty versus excisional atherectomy trial (CAVEAT)

Objectives. We examined the results of the Coronary Angioplasty Versus Excisional Atherectomy Trial (CAVEAT) to determine the characteristics and consequences of creatine kinase (CK) and creatine kinase, MB myocardial isoenzyme fraction (CK-MB) elevations after percutaneous coronary intervention.Background. Enzyme elevations after interventional procedures have usually been thought to be without long-term clinical consequences. However, recent preliminary reports have suggested that there are important long-term clinical sequelae in patients with even mild enzyme elevations after coronary procedures.Methods. Patients with new native lesions undergoing coronary intervention at 35 clinical sites were randomized to undergo percutaneous coronary angioplasty (n = 500) or directional coronary atherectomy (n = 512). Cardiac enzyme levels were measured 12 and 24 h after the interventional procedure and when clinically indicated for recurrent myocardial ischemia. Enzyme profiles were analyzed using a ratio that compared the peak enzyme level and the local laboratory upper limit of normal. Standard 12-lead electrocardiograms (ECGs) recorded before and after the procedure were interpreted by two independent readers who had no knowledge of the randomization data. Postprocedural myocardial infarction was defined as the appearance of new Q waves on the ECG, CK-MB levels three or more times the upper limit of normal or a total CK concentration two or more times the upper limit of normal when CK-MB levels were unavailable. Regression models were used to evaluate the predictive significance of a postintervention myocardial infarction with respect to clinical outcomes at 30 days and 1 year.Results. There were 78 myocardial infarctions in the atherectomy group and 34 in the angioplasty group (15.2% vs 6.8%, p = 0.001). Patients with a myocardial infarction more often had a repeat intervention or emergency coronary artery bypass surgery. Hospital length of stay was increased among patients with an infarction, as were mean hospital costs ($17,340.65 vs $11,308.47, p = 0.0003). Postprocedural myocardial infarction was highly predictive of mortality, bypass surgery or repeat intervention within 30 days (p < 0.0001).Conclusions. Myocardial infarction occurred commonly after coronary intervention in CAVEAT and was associated with a worse clinical outcome. Although the incidence of myocardial infarction was higher with atherectomy than with angioplasty, the baseline characteristics and consequences of the infarctions were similar between the treatments with regard to 30-day outcome. Myocardial enzyme elevations after an otherwise successful interventional procedure may identify a population at risk for a future cardiac event.

Observational versus randomized medical device testing before and after market approval—The atherectomy-versus-angioplasty controversy

Percutaneous transluminal coronary angioplasty was developed in the late 1970s as a nonsurgical alternative for revascularization of atherosclerotic coronary arteries. It gained widespread acceptance without a controlled trial. Introduced in 1986, directional coronary atherectomy was the first of other recently developed coronary devices that sought to improve on the results of angioplasty. It was approved in 1990 by the Food and Drug Administration (FDA) on the basis of observational data. Its use expanded rapidly, reaching over 35,000 procedures in 1992, accounting for more than 10% of all interventions. After premarket approval, two major randomized trials tested the hypothesis that atherectomy would be superior to angioplasty. Their results raised a cautionary flag and stood in contrast to projections made from prior observational data. It is concluded that randomized controlled trials validate claims of relative efficacy and safety of competing medical technologies, a lesson reflected in recent changes in policy at the FDA.

Intracoronary ultrasound imaging before and after directional coronary atherectomy: In vitro and clinical observations

The rate of restenosis after directional coronary atherectomy (DCA) is higher than expected. To elucidate why, the current study used intravascular ultrasound (IVUS) imaging to investigate the mechanism of DCA. An in vitro validation study was performed to determine the accuracy of the measurement of plaque removal by IVUS. DCA was performed in eight human atherosclerotic artery segments. The volume of removed plaque was measured by water displacement and was compared with the volume calculated from IVUS images. A clinical study of DCA was performed in 32 lesions. IVUS was performed in 28 lesions after successful DCA. Measurements of lumen dimensions from digital angiograms before and after DCA were compared with observations of lumen and plaque size from the cross-sectional IVUS images. In the in vitro study, the mean plaque volume removed by DCA was 19.9 ± 8.5 μl. The calculated estimate of removed plaque volume by IVUS was 18.6 ± 7.9 μl and correlated closely with the volume by water displacement ( r = 0.92). The calculated volume of plaque removed from histologic sections was 14.3 ± 6.0 μl and was linearly correlated with plaque volume by water displacement ( r = 0.81). In the clinical study, the angiographic mean minimum lumen diameter increased from 1.0 ± 0.4 to 2.7 ± 0.5 mm and the percentage stenosis decreased from 70% to 19% ( p < 0.0001). The IVUS images before and after DCA showed that the lumen DCA improved from 2.9 ± 1.5 to 7.0 ± 1.5 mm 2 ( p < 0.0001). In addition the vessel cross-sectional area (CSA) increased from 17.1 ± 5.9 to 18.7 ± 5.5 mm 2. The atheroma CSA was reduced from 14.2 ± 5.0 to 11.7 ± 4.8 mm 2. This combined effect of reduction in atheroma CSA and stretching of the outer vessel diameter resulted in an improvement in percentage plaque area stenosis from 83% ± 7% to 61% ± 9%. It is concluded that despite a successful angiographic appearance, DCA removed an average of 2.5 mm 2 from the atheroma, which corresponds to only 18% of the atheroma CSA. The total lumen CSA increased 4.1 mm 2; 61% of the new lumen was created by cutting and removal of plaque, whereas 39% of the new lumen was made by stretching the external wall of the artery. Despite an excellent angiographic result, IVUS imaging reveals that after DCA a significant amount of residual atheroma remains. As in balloon dilatation, a stretching effect is a significant component of DCA.

Directional atherectomy of coronary and saphenous vein graft ostial stenoses

Directional coronary atherectomy (DCA) has been proposed as an alternative to balloon dilatation for treating coronary ostial stenoses, but the long-term efficacy of this procedure has not been well studied. To determine the procedural success and long-term efficacy of DCA for ostial stenoses, clinical data from 1 large registry database and from 2 single centers were retrospectively reviewed. Patients included in the study underwent DCA of aortocoronary (left main or right coronary artery), non-aortocoronary (left anterior descending or circumflex), or vein graft ostial stenoses. In 158 patients undergoing DCA of 160 lesions (30 left main or right coronary, 73 left anterior descending or circumflex, and 57 vein graft stenoses), overall procedural success, defined as < 50% residual stenosis without death, Q-wave myocardial infarction, or need for urgent bypass graft surgery, was 87%. The major complication rate was 0.6%. There were no deaths or Q-wave infarctions; only 1 patient required urgent bypass surgery. Other complications included non-Q-wave myocardial infarction (9%), arterial dissection (9%), abrupt closure (4%), and distal coronary embolization (4%). Angiographic follow-up was available for 65% of the 138 eligible patients. The overall 6-month angiographic restenosis rate, defined as >50% diameter stenosis at the site of DCA, was 48% (de novo lesions 40% and restenotic lesions 61%). Restenosis rates for de novo and restenotic lesions were: aortocoronary ( 33% 50% ), native coronary ( 38% 35% ), and vein graft ( 47% 93% ), respectively. We conclude that DCA of ostial stenoses is an effective revascularization strategy associated with a high procedural success rate and a low incidence of major complications. Restenosis, especially in restenotic saphenous vein graft lesions, continues to limit the long-term efficacy of the procedure.

Directional atherectomy versus balloon angioplasty for coronary ostial and nonostial left anterior descending coronary artery lesions: Results from a randomized multicenter trial

We hypothesized that atherectomy would be superior to balloon angioplasty for ostial and nonostial left anterior descending coronary artery lesions. Balloon angioplasty of ostial coronary artery lesions has been associated with a lower procedural success rate and a higher rate of complications and of restenosis than angioplasty of nonostial stenoses. Directional coronary atherectomy has been proposed as an alternative therapy for ostial lesions. In the Coronary Angioplasty Versus Excisional Atherectomy Trial (CAVEAT-I), 1,012 patients were randomized to undergo either procedure; 563 patients had proximal left anterior descending coronary artery lesions, of which 74 were ostial. We compared balloon angioplasty with directional atherectomy for early and 6-month results for ostial as well as nonostial proximal left anterior descending coronary artery lesions. Directional atherectomy led to an initially higher gain in minimal lumen diameter for ostial lesions (1.13 vs. 0.56 mm, respectively, p < 0.001) but a higher rate of adjudicated non-Q wave myocardial infarction (24% vs. 13%, respectively, p < 0.001) than balloon angioplasty and no improvement in restenosis rates (48% vs. 46%, respectively). In the nonostial proximal left anterior descending coronary artery lesions, angiographic restenosis was reduced (51% vs. 66%, p = 0.012), but this was also associated with a higher rate of periprocedural myocardial infarction (8% vs. 2%, p = 0.008 by site and 24% vs. 8%, p < 0.001 by adjudication) and no difference in the need for subsequent coronary artery bypass surgery (7.3% vs. 8.4%, respectively) or repeat percutaneous coronary intervention (24% vs. 26%, respectively). For ostial left anterior descending coronary artery stenoses, both procedures yielded similar rates of initial success and restenosis, but atherectomy was associated with more non-Q wave myocardial infarction. In this trial the predominant angiographic benefit (increased early gain and less angiographic restenosis) of atherectomy for the left anterior descending coronary artery was in proximal nonostial lesions. However, the tradeoffs for this angiographic advantage were more in-hospital myocardial infarctions and no decrease in clinical restenosis.

Quantitative assessment with intracoronary ultrasound of the mechanisms of restenosis after percutaneous transluminal coronary angioplasty and directional coronary atherectomy

The mechanisms of immediate and late changes after percutaneous transluminal coronary angioplasty (PTCA) and directional coronary atherectomy (DCA) were assessed by serial ultrasound imaging in 18 patients treated with PTCA and 16 treated with DCA before, immediately after, and 6 months after coronary interventions. A reduction in plaque area was the main operative mechanism of DCA, explaining 66% of lumen enlargement. In the PTCA group, the increase in lumen area was the result of a more balanced combination of plaque reduction (52% of lumen increase) and increase in total lumen area (48%); p < 0.05 versus DCA. In the PTCA group, this last mechanism was prevalent (p < 0.05) in the lesions showing wall fracture or dissection after treatment and in the lesions with a mixed or calcific composition. In the PTCA group, concentric lesions showed a greater plaque compression than eccentric lesions (p < 0.02). Plaque increase was responsible for 92% and 32% of the late lumen loss after DCA and after PTCA, respectively (p < 0.05). In PTCA patients, a chronic reduction in total vessel area was the main operative mechanism of lumen reduction (67%) and was prevalent in lesions with a mixed or calcific composition (p < 0.05).

A Multicenter, Randomized Trial of Coronary Angioplasty Versus Directional Atherectomy for Patients With Saphenous Vein Bypass Graft Lesions

Directional coronary atherectomy and percutaneous transluminal coronary angioplasty have both been used in symptomatic patients with coronary saphenous vein bypass graft stenoses. The relative merits of plaque excision and removal versus balloon dilatation remain uncertain. We compared outcomes after directional coronary atherectomy or angioplasty in patients with de novo bypass graft stenoses. Fifty-four North American and European sites randomized 305 patients with de novo vein graft lesions to atherectomy (n = 149) or angioplasty (n = 156). Quantitative coronary angiography at a core laboratory assessed initial and 6-month results. Initial angiographic success was greater with atherectomy (89.2% versus 79.0%), as was initial luminal gain (1.45 versus 1.12 mm, P < .001). Distal embolization was increased with atherectomy (P = .012), and a trend was shown toward more non-Q-wave myocardial infarction (P = .09). Although the 6-month net minimum luminal diameter gain was 0.68 mm for atherectomy and 0.50 mm for angioplasty, the restenosis rates were similar, 45.6% for atherectomy and 50.5% for angioplasty (P = .491). At 6 months, there was a trend toward decreased repeated target-vessel interventions for atherectomy (P = .092); in addition, 13.2% of patients treated with atherectomy versus 22.4% of the angioplasty patients (P = .041) required repeated percutaneous intervention of the initial target lesion. Atherectomy of de novo vein graft lesions was associated with improved initial angiographic success and luminal diameter but also with increased distal embolization. There was no difference in 6-month restenosis rates, although primary atherectomy patients tended to require fewer target-vessel revascularization procedures.

Intracoronary ultrasound—defined plaque composition: Computer-aided plaque characterization and correlation with histologic samples obtained during directional coronary atherectomy

The ability to classify lesion composition accurately may be important for selecting or guiding interventional therapy and for understanding the pathophysiologic basis of individual lesions. To assess the usefulness of ultrasound in classifying lesions, intracoronary ultrasound images were obtained from 44 atherosclerotic lesions in patients before directional atherectomy. Lesions were classified by visual analysis and by computer-assisted gray-level statistics. Atherectomy samples were evaluated histologically for elastosis and calcium and quantitatively by morphometric analysis for various tissue components. The computer-assisted quantitative quantitative ultrasound images were found to have distinctive histologic features. Lesions with predominantly echogenic plaque had a larger fraction of dense fibrous, elastic, or calcified tissue. Leions with predominantly echolucent soft plaque had a greater fraction of loose fibrous, smooth-muscle, thrombotic, or necrotic elements. Thus intracoronary ultrasound allows accurate classification of lesion composition in patients.

Comparison of coronary lesions obtained by directional coronary atherectomy in unstable angina, stable angina, and restenosis after either atherectomy or angioplasty

The present study investigated the incidence of the histopathologic lesions and of growth factor expression in a consecutive series of directional coronary atherectomy (DCA) samples from 40 unstable angina pectoris patients without prior acute myocardial infarction and compared the findings with those obtained in DCA samples from 18 patients with stable angina without previous infarction and 18 patients with restenosis. We investigated coronary thrombosis, neointimal hyperplasia, and inflammation. For unstable angina, we correlated the angiographic Ambrose plaque subtypes with the histopathologic findings. The immunophenotype of plaque cells and the growth factor expression were assessed with specific antibodies for cell characterization and for the expression of basic fibroblast and platelet-derived AA and AB growth factors and receptors. The incidence of coronary thrombosis was 35% in patients with unstable angina, 17% in those with stable angina, and 11% in patients with restenosis. Neointimal hyperplasia was found in 38% of unstable angina cases, in 17% of stable angina cases, and in 83% of restenosis cases. Inflammation without thrombus or accelerated progression occurred in 20% of unstable angina and 6% of stable angina samples. In 52% of unstable angina cases, inflammation coexisted with thrombosis and/or neointimal hyperplasia. In the unstable angina group, 71% of the plaques with thrombus had a corresponding angiographic pattern of complicated lesions. The growth factor expression, reported as percentage of cells immunostaining with different growth factor antibodies, was highest in restenosis, followed by unstable angina and stable angina lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Cytomegalovirus Replication Is Not a Cause of Instability in Unstable Angina

Unstable angina is most frequently caused by coronary thrombosis, with or without plaque fissure, but the mechanisms underlying these events are still speculative. Since cytomegalovirus (CMV) antigens and DNA encoding CMV major immediate-early (MIE) gene have been detected in atherosclerotic arterial walls, the active replication of CMV may be responsible for plaque instability. Therefore the expression of CMV MIE gene mRNA, an early marker of viral replication, was assessed in coronary atherectomy specimens from patients with stable or unstable angina. Twenty patients with unstable angina (12 men and 8 women; mean age, 62 years; range, 44 to 89 years) and 20 patients with stable angina (16 men and 4 women; mean age, 62 years; range, 43 to 81 years) who underwent successful directional coronary atherectomy were enrolled in the study. The efficiency of mRNA extraction, transcription, and amplification from each coronary atherectomy specimen was assessed by performance of reverse transcription and thermal cycling amplification of a 548-bp human beta-actin cDNA segment. After Southern blotting and hybridization with a specific probe, all specimens but one showed a positive hybridization signal. The negative sample was excluded from the study. Reverse transcription and thermal cycling amplification of a 145-bp CMV cDNA segment of the MIE gene were then carried out. After Southern blotting and hybridization with a specific probe, none of the specimens showed a positive hybridization signal. Plasmid pACYC 184 containing the Xba I-inserted MIE gene cDNA was used as a positive control: as few as 10 molecules of the plasmid per reaction were detectable after amplification. Our results do not support the hypothesis that, in patients with unstable angina, replication of CMV in coronary atherosclerotic plaques is a major cause of plaque instability. These findings suggest that the research for the causes of unstable angina should be directed toward processes other than CMV replication.