Preliminary experience with adjunct directional coronary atherectomy after high-speed rotational atherectomy in the treatment of calcific coronary artery disease

Comparison of Clinical and Angiographic Outcomes After Bare Metal Stents and Drug-Eluting Stents Following Rotational Atherectomy

Few studies have investigated the clinical outcomes of rotational atherectomy (RA) prior to and during the drugeluting stent (DES) era. The goal of this study was to assess the long-term outcome after RA followed by DES and bare metal stent (BMS) implantation in complex calcified coronary lesions and to compare the outcomes among various DESs.This was a single center retrospective observational study. Consecutive 406 patients who underwent elective RA followed by BMS or DES implantation at our institution from 2001 to 2011 were included. This study compared the long-term outcomes after treatment with RA among BMS and 3 different DESs (sirolimus-eluting stent, paclitaxel-eluting stent, and everolimus-eluting stent) implantation.The mean follow-up period was 4.6 years. Patients with DES were older and exhibited more vessel disease, longer lesion length, and smaller vessel size. Patients with BMS had a significantly higher rate of target lesion revascularization, restenosis, and larger late lumen loss than those with DES. Composite events including mortality, ACS, and target vessel revascularization were significantly higher in the BMS-RA group than in the DES-RA group. After adjustment, BMS remained an independent predictor of MACE and ACS plus death in patients treated with RA. However, there were no significant differences in late lumen loss, restenosis rate, and MACE among the 3 DES.The combination of DES-RA has a favorable effect in both the angiographic and clinical outcomes compared with BMS-RA. However, no significant differences in late loss and events rates were observed among the 3 DES groups.

Practical application of coronary imaging devices in cardiovascular intervention

The significant morbidity and mortality associated with coronary artery disease has spurred the development of intravascular imaging devices to optimize the detection and assessment of coronary lesions and percutaneous coronary interventions. Intravascular ultrasound (IVUS) uses reflected ultrasound waves to quantitatively and qualitatively assess lesions; integrated backscatter and virtual histology IVUS more precisely characterizes plaque composition; angioscopy directly visualize thrombus and plaque; optical coherence tomography using near-infrared (NIR) light with very high spatial resolution provides more accurate images; and the recently introduced NIR spectroscopy identifies chemical components in coronary artery plaques based on differential light absorption in the NIR spectrum. This article reviews usefulness of these devices and hybrids thereof.

Directional atherectomy of a calcified lesion using a new atherectomy device

We report on a case of directional atherectomy performed on a calcified coronary lesion using a novel device with a hardened titanium cutter. The successful removal of calcified plaque was documented by intravascular ultrasound assessment and confirmed by histopathological analysis of the obtained plaque specimen.

Quantification of intramural calcification in coronary intravascular ultrasound images with automated image analysis

BACKGROUND

Recent studies have documented the utility of intravascular ultrasonography in quantifying coronary morphologic characteristics and determining an appropriate intervention. Unfortunately, its potential for quantifying lesion calcification is limited by subjective evaluation and manual tracing. The aim of this study was to develop an objective automated method for quantifying calcification in intracoronary images with digital image analysis.

METHODS

Images of human coronary arteries acquired with a 30 MHz intracoronary ultrasound catheter were evaluated with digital image analysis and compared with manual tracings. Calcifications were automatically identified as highly echogenic regions detected by global thresholding within sectors of acoustic shadowing defined as regions devoid of texture.

RESULTS

The mean percentage agreement, sensitivity, and specificity of detecting calcification in 1-degree sectors of calcified vessels were 82%, 73%, and 87%, respectively. Similar results were obtained in noncalcified images.

CONCLUSION

The accuracy of this automated technique was comparable to interoperator and intraoperator variability in manually tracing calcification.

A case of favorable dilation of protected left main coronary artery lesion achieved through performance of adjunctive DCA on residual stenosis following use of rotablator

It is believed that directional coronary atherectomy (DCA) is more suitable than percutaneous transluminal coronary angioplasty for lesions such as severe eccentric lesions, ostial lesions, and branch lesions. However, it remains a fact that lesions that are also highly calcified are often suboptimal, since there may be difficulties such as in insertion of the housing and in sufficient cutting and removal. On the other hand, Rotablator is effective on calcified lesions, but afterward, dilation by balloon angioplasty for residual stenosis becomes necessary in many cases. This is a report of the authors' experience on an interesting case in which favorable dilation of a lesion in the protected left main coronary artery (LMCA) was achieved by using Rotablator after confirmation of a high degree of calcification by means of intravascular ultrasound (IVUS) echocardiograhy, followed by the performance of DCA on the residual stenosis.

Contribution of inadequate arterial remodeling to the development of focal coronary artery stenoses. An intravascular ultrasound study

BACKGROUND

Adaptive remodeling occurs to compensate for the accumulation of atherosclerotic plaque. Lumen reduction depends on the relative rates of plaque deposition and adaptive remodeling responses. Intravascular ultrasound permits detailed, high-quality, cross-sectional imaging of the coronary arteries in vivo.

METHODS AND RESULTS

Preintervention intravascular ultrasound was used to study 603 focal, new, nonostial significant coronary artery stenoses in patients with chronic stable angina. Measurements of the target lesion of the external elastic membrane (EEM), lumen, and plaque plus media (P&M; P&M = EEM - Lumen) cross-sectional areas (CSAs) were compared with a proximal reference segment (most normal-looking cross section within 10 mm proximal to the lesion but distal to any side branch). Inadequate remodeling was defined as lesion/ reference EEM CSA that exceeded the upper limits of normal arterial tapering (lesion/reference EEM CSA ratio < or = 0.78 or a 21% reduction in EEM CSA per 10-mm length). Overall, the lesion/reference EEM CSA ratio was 1.00 +/- 0.22; 15% of lesions had inadequate remodeling, and 37% of the 603 lesions had less plaque than expected. This represented a lesion-specific response. The only predictor of inadequate remodeling was the arc of superficial lesion calcium.

CONCLUSIONS

Inadequate remodeling is present in at least 15% of chronic, focal, new coronary arterial stenoses in patients with stable angina. The magnitude of arterial remodeling appears to be a lesion-specific response.

Intravascular ultrasound insights into mechanisms of stenosis formation and restenosis

Using intravascular ultrasound (IVUS), stenosis formation and restenosis (or late lumen loss following coronary angioplasty procedures) can be subdivided into two distinct underlying components: tissue accumulation and arterial remodeling. Arterial remodeling is defined as a change in total arterial cross-sectional area over time; it can be adaptive (an increase in arterial cross-sectional area as a compensatory response to plaque accumulation) or pathologic (a decrease in arterial cross-sectional area or chronic arterial shrinkage). Adaptive arterial remodeling can delay the development of coronary artery stenoses and prevent restenosis; pathologic remodeling can contribute to de novo lesion formation and has been shown to be the dominant mechanism of restenosis following coronary intervention. Serial IVUS studies have also been used to study the natural history of the restenosis process; adaptive remodeling occurs early (within 1 month) and pathologic remodeling occurs late (between 1 and 6 months) after intervention. The residual plaque burden postintervention acts as an amplifier in this process.

Determinants and correlates of target lesion calcium in coronary artery disease: a clinical, angiographic and intravascular ultrasound study

OBJECTIVES

This report used intravascular ultrasound and quantitative coronary angiography to explore the relation between lesion-associated calcium and risk factors, clinical presentation and angiographic severity of coronary artery stenoses.

BACKGROUND

Coronary artery calcium is a marker for significant coronary atherosclerosis. Noninvasive procedures are being proposed as screening tests for coronary artery disease. Intravascular ultrasound identification of tissue calcium has been validated in vitro.

METHODS

Independent chart review, preintervention intravascular ultrasound imaging and coronary angiography were used to study primary native vessel lesions in 1,442 patients. Target lesions and reference segments were evaluated according to previously published quantitative and qualitative methods. Results are presented as mean value +/- SD.

RESULTS

Overall, 1,043 lesions contained target lesion calcium (72%); the arc of target lesion calcium was 110 +/- 109 degrees. Lesions with an ultrasound plaque burden > 0.75 or an angiographic diameter stenosis > 0.25 had a prevalence of calcium of at least 65%, with a mean arc > 100 degrees. Intermediate lesions had as much target lesion calcium as did angiographically severe lesions. Using multivariate linear regression analysis, patient age, stable (vs. unstable) angina and the intravascular ultrasound lesion site and reference segment plaque burden (but not the angiographic diameter stenosis) were the independent predictors of the arc of target lesion calcium (all p < 0.0001).

CONCLUSIONS

Intravascular ultrasound analysis shows that coronary calcification correlates with plaque burden but not with degree of lumen compromise. Thus, the noninvasive detection of coronary calcium is predictive of future cardiac events, presumably because coronary calcification is a marker for overall atherosclerotic plaque burden. Coronary calcium increases with increasing patient age and is less common in unstable lesion subsets.

Is pre-intervention intravascular ultrasound necessary in evaluating target lesion calcification in patients undergoing transcatheter therapy?

To identify a subset of patients with a high probability of extensive calcification for further intravascular ultrasound (IVUS) examination, the frequency and extent of target lesion calcification as assessed by IVUS and its correlations with age, gender and risk factors as well as the value of angiography in identifying ultrasound calcification were analyzed in 88 patients undergoing balloon angioplasty for significant coronary atherosclerotic stenosis. The extent of calcification was semi-quantitatively graded as 0: no calcification; +: calcification arc < 90 degrees; ++: calcification arc from 90 degrees to 180 degrees; : calcification arc > 180 degrees. The distribution pattern of calcification was classified as superficial, deep or mixed. The results indicate: (1) the frequency of target lesion calcification was 38.6%, of which 52.9% showed a superficial pattern and 56.0% had a calcification arc < 90 degrees; and (2) only age was significantly associated with target lesion calcification in all of the patients. The frequency of calcification was remarkably higher in patients > or = 60 years old than in patients < or = 60 years old (61.9% vs 17.4%, p < 0.001); (3) among patients less than 60 years old, those with calcification had a higher average number of risk factors than those without; and (4) the total sensitivity of angiography in identifying ultrasound calcification was 43.6%, with a significantly higher sensitivity for calcification arc > 180 degrees and mixed pattern. In conclusion, pre-intervention IVUS may be necessary in patients > or = 60 years old and in those < 60 years old with more than two risk factors in selecting devices to optimize interventional strategies.

Arterial remodeling after coronary angioplasty: a serial intravascular ultrasound study

BACKGROUND

Restenosis occurs after 30% to 50% of transcatheter coronary procedures; however, the natural history and pathophysiology of restenosis are still incompletely understood.

METHODS AND RESULTS

Serial (postintervention and follow-up) intravascular ultrasound imaging was used to study 212 native coronary lesions in 209 patients after percutaneous transluminal coronary angioplasty, directional coronary atherectomy, rotational atherectomy, or excimer laser angioplasty. The external elastic membrane (EEM) and lumen cross-sectional areas (CSA) were measured; plaque plus media (P+M) CSA was calculated as EEM minus lumen CSA. The anatomic slice selected for serial analysis had an axial location within the target lesion at the smallest follow-up lumen CSA. At follow-up, 73% of the decrease in lumen (from 6.6+/-2.5 to 4.0+/-3.7 mm2, P<.0001) was due to a decrease in EEM (from 20.1+/-6.4 to 18.2+/-6.4 mm2, P<.0001); 27% was due to an increase in P+M (from 13.5+/-5.5 to 14.2+/-5.4 mm2, P<.0001). Delta Lumen CSA correlated more strongly with delta EEM CSA (r=.751, P<.0001) than with delta P+M CSA (r=.284, P<.0001). Delta EEM was bidirectional; 47 lesions (22%) showed an increase in EEM. Despite a greater increase in P+M (1.5+/-2.5 versus 0.5+/-2.0 mm2, P=.0009), lesions exhibiting an increase in EEM had (1) no change in lumen (-0.1+/-3.3 versus 3.6+/-2.3 mm2, P<.0001), (2) a reduced restenosis rate (26% versus 62%, P<.0001), and (3) a 49% frequency of late lumen gain (versus 1%, P<.0001) compared with lesions with no increase in EEM.

CONCLUSIONS

Restenosis appears to be determined primarily by the direction and magnitude of vessel wall remodeling (delta EEM). An increase in EEM is adaptive, whereas a decrease in EEM contributes to restenosis.

Intravascular ultrasound predictors of restenosis after percutaneous transcatheter coronary revascularization

OBJECTIVES

This study sought to evaluate preintervention and postintervention intravascular ultrasound studies for potential predictors of angiographic restenosis and to use ultrasound predictors of restenosis to enhance our understanding of the pathophysiology of the restenosis disease process.

BACKGROUND

Restenosis remains the major limitation of percutaneous transcatheter coronary revascularization. Although its mechanisms remain incompletely understood, numerous studies have identified some of the clinical, anatomic and procedural risk factors for restenosis. Intravascular ultrasound imaging of target lesions before and after catheter-based treatment consistently demonstrates more target lesion calcium, more extensive reference segment atherosclerosis, smaller final lumen dimensions, significant residual plaque burden and a greater degree of tissue trauma than is evident by angiography.

METHODS

Intravascular ultrasound studies were performed in 360 nonstented native coronary artery lesions (final diameter stenosis 18 +/- 11%) in 351 patients for whom follow-up angiographic data were available 6.4 +/- 3.6 months later. Hospital charts were reviewed, and qualitative and quantitative coronary angiographic and intravascular ultrasound analyses were performed by independent core laboratories. Four dependent angiographic end points were tested: restenosis as a binary definition (> or = 50% diameter stenosis at follow-up) was the primary end point; follow-up diameter stenosis, late lumen loss and follow-up minimal lumen diameter were the secondary end points.

RESULTS

Reference vessel size, the preintervention quantitative coronary angiographic assessment of lesion severity and the postintervention intravascular ultrasound cross-sectional measurements predicted the late angiographic results. In particular, the intravascular ultrasound postintervention cross-sectional narrowing (plaque plus media cross-sectional area divided by external elastic membrane cross-sectional area) predicted the primary end point (restenosis) and two of the three secondary end points (follow-up diameter stenosis and late lumen loss) and was therefore the most consistent predictor of restenosis.

CONCLUSIONS

Intravascular ultrasound variables are more powerful and consistent predictors of angiographic restenosis than currently accepted clinical or angiographic risk factors.

Mechanisms and immediate and long-term results of adjunct directional coronary atherectomy after rotational atherectomy

OBJECTIVES

The purpose of this study was to confirm the mechanisms and the immediate and long-term results of rotational atherectomy and adjunct directional coronary atherectomy.

BACKGROUND

Rotational atherectomy is best suited for treating calcific stenoses, but the ability of rotational atherectomy alone to optimize lumen dimensions in large vessels is limited; this is only partly improved by adjunct balloon angioplasty.

METHODS

We treated 165 lesions in 163 patients by use of rotational atherectomy and adjunct directional coronary atherectomy. Quantitative angiography and intravascular ultrasound were used for lesion analysis. A matched comparison with 208 lesions treated with rotational atherectomy and adjunct coronary angioplasty was performed. Patients were then followed up for at least 9 months, and target-lesion revascularization was assessed.

RESULTS

In the 61 lesions imaged sequentially, lumen area increased from 1.7 +/- 0.8 (mean +/- 1 SD) to 3.9 +/- 1.1 mm(2) after rotational atherectomy, owing to a decrease in plaque plus media area from 16.8 +/- 5.0 to 15.2 +/- 5.2 mm(2) (both p < 0.0001). After adjunct directional coronary atherectomy, lumen area increased even more to 6.7 +/- 2.0 mm(2) (vs. 5.1 +/- 1.4 mm(2) after adjunct coronary angioplasty, p < 0.0001) as a result of both vessel expansion (18.8 +/ 5.3 to 20.8 +/- 5.7 mm(2)) and additional plaque removal (to 14.1 +/- 5.0 mm(2), all p < 0.0001). The total arcs of calcium decreased from 207 +/- 107 degrees to 166 +/- 93 degrees after rotational atherectomy and to 145 +/- 87 degrees after directional coronary atherectomy. Overall, procedural success was 96%, and final diameter stenosis was 15 +/- 17%. Target-lesion revascularization was 23%. The only independent predictor of target-lesion revascularization was a larger overall atherectomy index (84% vs. 59%, p = 0.048).

CONCLUSIONS

There is a synergistic relationship between rotational atherectomy and directional coronary atherectomy in the treatment of calcific lesions. The immediate results show a high procedural success--lumen dimensions were larger and late target-lesion revascularization was lower in lesions treated with rotational atherectomy and directional coronary atherectomy than in those treated with rotational atherectomy and adjunct balloon angioplasty.

The dilemma of diagnosing coronary calcification: angiography versus intravascular ultrasound

OBJECTIVES

We sought to determine whether careful examination of angiograms in conjunction with other clinical information could reliably detect, quantitate and localize target lesion calcification before a coronary intervention.

BACKGROUND

The presence, extent and location of calcium in coronary artery lesions are important determinants of outcome after coronary intervention. Intravascular ultrasound is proposed as a superior technique for identifying patients with coronary artery calcification. However, the precise role of this costly and invasive method has not yet been established.

METHODS

Target lesion calcification was assessed in 183 patients (155 men; mean [+/-SD] age 58 +/- 10 years) by angiography and intravascular ultrasound before a planned percutaneous coronary intervention.

RESULTS

Ultrasound detected calcium in 138 patients (>90 degrees in 56, 91 degrees to 180 degrees in 52, 181 degrees to 270 degrees in 22 and > 270 degrees in 8), whereas angiography showed calcification in 63 (1+ in 32, 2+ in 27 and 3+ in 4). The two techniques agreed in 92 patients and disagreed in 91. Sensitivity and specificity of angiography were 40% and 82%, respectively. The arc of calcium by ultrasound was greater in patients with angiographically visible calcification (175 degrees +/- 85 degrees vs. 108 degrees +/- 71 degrees, p=0.0001). The depth of calcification by ultrasound was superficial in 61 patients (44%), deep in 68 (49%) and mixed in 8 (7%). The sensitivity of angiography in identifying superficial calcium was 35%. Of 120 patients without angiographically visible calcium at the target lesion site, 83 showed calcium by ultrasound. The only predictor of ultrasound calcium in these 120 patients was angiographic calcification elsewhere in the coronary tree (p=0.0001). The probability of any calcium and superficial >90 degrees calcium were 60% and 12%, respectively, in the 90 patients without angiographic calcifications anywhere in the coronary tree.

CONCLUSIONS

Despite poor sensitivity, angiography may help identify patients requiring intravascular ultrasound. When it is angiographically visible, the arc of calcium is likely to be large and superficial. Angiographic calcification at a remote site is a predictor of angiographically undetected target lesion calcium. Patients without angiographic calcification in the coronary tree may not need routine ultrasound examination, as the likelihood of >90 degrees superficial calcium is low.

Mechanisms of lumen enlargement after excimer laser coronary angioplasty. An intravascular ultrasound study

BACKGROUND

The mechanisms of excimer laser coronary angioplasty (ELCA) have never been studied in human coronary arteries in vivo.

METHODS AND RESULTS

ELCA was used to treat 202 lesions in 190 patients. Forty-nine lesions in 48 patients were studied by use of sequential (before and after ELCA and after adjunctive device therapy) intravascular ultrasound (IVUS). External elastic membrane (EEM), lumen, and plaque+media (P+M = EEM-lumen) cross-sectional areas (CSAs) and lesion arcs of calcium were measured before and after ELCA and after adjunct device use. Lumen improvement after ELCA (1.4 +/- 0.5 to 2.7 +/- 0.8 mm2) was the result of both tissue ablation (decrease in P+M CSA from 16.8 +/- 7.1 to 15.9 +/- 6.7 mm2, P < .0001) and vessel expansion (increase in EEM CSA from 18.2 +/- 7.1 to 18.6 +/- 6.8 mm2, P = .0245), with no change in calcium. The decrease in P+M CSA was 39% of the CSA of the laser catheter used. Dissections were present in 39% of lesions, 84% within superficial calcium; fibrocalcific deposits developed a "fragmented" appearance.

CONCLUSIONS

ELCA increased lumen CSA by both atheroablation and vessel expansion without calcium ablation. Superficial fibrocalcific deposits developed a characteristic fragmented appearance. These findings support both photoablation and forced vessel expansion as mechanisms of lumen enlargement and plaque dissection after ELCA.

Mechanism of high-speed rotational atherectomy and adjunctive balloon angioplasty revisited by quantitative coronary angiography: edge detection versus videodensitometry

High-speed rotational coronary atherectomy (RA) is primarily used to treat complex lesions. Quantitative angiographic analysis of such complex lesions by edge detection is often unsuitable, whereas videodensitometry, measuring vessel dimensions independently of the target stenosis contours, may offer potential advantages. To gain insight into the operative mechanism of RA and to study the agreement between the two quantitative angiographic methods in measuring the minimal luminal cross-sectional area, the edge detection and videodensitometry techniques were applied to coronary angiograms of 21 lesions in 19 patients with symptoms who underwent successful RA and balloon angioplasty (BA). Obstruction diameter as determined by edge detection increased from 1.00 +/- 0.31 mm before intervention to 1.35 +/- 0.29 mm after RA (p < 0.001) and further increased to 1.74 +/- 0.33 mm after adjunctive BA (p > 0.001). The mean between-method difference (edge detection minus videodensitometry) was 0.34 mm2 before intervention, 0.13 mm2 after RA, and 0.09 mm2 after adjunctive BA (not significant). The standard deviation of the differences decreased from +/- 0.87 mm2 before intervention to +/- 0.80 mm2 after RA (not significant) and increased after BA significantly to +/- 1.21 mm2 (p < 0.05). Thus edge detection and videodensitometry provided equivalent immediate angiographic results after RA and adjunctive BA. The good agreement after RA may reflect the operative mechanism of RA, which by ablation of noncompliant plaque material yields a circular symmetric lumen with smooth surface. The increased dispersion of the between-method differences observed after adjunctive BA presumably results from dissections, plaque ruptures, and loss of luminal smoothness after balloon dilatation.

Detection of intralesional calcium by intracoronary ultrasound depends on the histologic pattern

This study was designed to examine the accuracy of intravascular ultrasound in detecting different histologic types of calcium pattern in human coronary artery atherosclerotic lesions. Previous studies have shown that calcium deposits in atherosclerotic lesions may occur in various forms and that intravascular ultrasound is a sensitive technique to detect calcium in atherosclerotic lesions. However, there has been no distinction between varying image representations of calcium and different histologic patterns of intralesional calcific deposits. Calcific lesions have an important clinical impact on the outcome of intracoronary transcatheter therapy, and the varying types of calcium may also play a role in the guidance of intracoronary interventions. Fifty fresh coronary vessel segments were studied by intracoronary ultrasound imaging and the images compared with the corresponding histologic sections. With intracoronary ultrasound imaging, calcium was defined as bright echo with corresponding sharp edged shadowing in the distal field. Three different histologic types of calcification were defined, and the sensitivity and specificity of the detection by intravascular ultrasound were determined for each type. Dense calcified plaques (type 1) were found 18 cases, microcalcification (small flecks of calcium) with single calcium fleck size < or = 0.05 mm (type 2) in 12 cases, and combination of calcified plaque surrounded by small calcium flecks (type 3) in 3 cases. In 17 (34%) coronary vessel segments, histologic analyses detected no calcium. Intracoronary ultrasound correctly detected 16 (89%) of 18 cases of type 1 calcification, 2 (17%) of 12 type 2, and all 3 (100%) type 3. Sensitivity for detection of type 1 and 3 calcification was 90%, with specificity of 100%.(ABSTRACT TRUNCATED AT 250 WORDS)