Compensatory enlargement of the coronary artery in acute myocardial infarction

Association of insulin resistance and coronary artery remodeling: an intravascular ultrasound study

Background

There are few studies that investigated the correlation between insulin resistance (IR) and the coronary artery remodeling. The aim of the study is to investigate the association of IR measured by homeostasis model assessment of insulin resistance (HOMA-IR) and coronary artery remodeling evaluated by intravascular ultrasound (IVUS).

Methods

A total of 298 consecutive patients who received percutaneous coronary interventions under IVUS guidance were retrospectively enrolled. The value of HOMA-IR more than 2.5 was considered as IR positive. Metabolic syndrome was classified according to NCEP ATP III guidelines. The remodeling index was defined as the ratio of the external elastic membrane (EEM) area at the lesion site to the EEM area at the proximal reference site.

Results

A total of 369 lesions were analyzed (161 lesions in HOMA-IR positive and 208 lesions in HOMA-IR negative). Remodeling index was significantly higher in the HOMA-IR positive group compared with the negative group (HOMA-IR positive vs. negative: 1.074 ± 0.109 vs. 1.042 ± 0.131, p = 0.013). There was a significant positive correlation between remodeling index and HOMA-IR (p = 0.010). Analysis of HOMA-IR according to remodeling groups showed increasing tendency of HOMA-IR, and it was statistically significant (p = 0.045). Multivariate analysis revealed that only HOMA-IR was an independent predictor of remodeling index (r = 0.166, p = 0.018).

Conclusion

Increased IR estimated by HOMA-IR was significantly associated with a higher remodeling index and positive coronary artery remodeling.

High-resolution MRI of the vessel wall in patients with symptomatic atherosclerotic stenosis of the middle cerebral artery

Intracranial atherosclerosis is associated with recurrent ischemic stroke. High-resolution MRI (HR MRI) can provide information about atheroma in vivo. We aimed to analyze and compare vascular wall imaging characteristics between patients with symptomatic and asymptomatic atherosclerotic stenosis of the middle cerebral artery (MCA) using 3.0 Tesla HR MRI. The HR MRI protocol included four different scans: black blood T1-weighted, T2-weighted and proton density-weighted MRI, as well as three-dimensional turbo spin echo imaging techniques with multiplanar reconstruction. Plaque characteristics, including location, morphology, and signal intensity, were analyzed in 51 patients (29 symptomatic, 22 asymptomatic) with atherosclerotic stenosis of the middle cerebral artery. The vessel wall area, lumen area, and plaque area (PA) were also calculated and compared between the symptomatic and asymptomatic groups. We found that PA, remodeling index (RI), and positive remodeling (PR) prevalence were significantly greater in the symptomatic group than in the asymptomatic group (PA: p=0.033; RI: p=0.020; PR: p=0.032). Plaque location in the superior aspect of the vessel wall and irregular plaque surface were more frequently observed in the symptomatic group than in the asymptomatic group (superior location: p=0.031; irregular surface: p=0.036). Moreover, multivariate logistic regression identified plaque location on the superior wall as an independent predictor of symptomatic MCA stenosis (odds ratio: 4.471; p=0.039). Therefore, we can conclude that patients with symptomatic atherosclerotic stenosis of the MCA are more likely to have larger plaques, PR, superiorly located plaques, and irregular plaque surface. These characteristics are promising factors for stratifying stroke risk.

Culprit lesion remodelling and long-term prognosis in patients with acute coronary syndrome: an intravascular ultrasound study

AIMS

Positive arterial remodelling is recognized as one of the morphological characteristics of the vulnerable plaque. Limited data are available on a long-term outcome of acute coronary syndrome (ACS) patients with culprit lesion positive arterial remodelling (PR). The aim of this study was to investigate the long-term impact of culprit lesion PR in patients with ACS.

METHODS AND RESULTS

In 134 patients with ACS, intravascular ultrasound (IVUS) was performed to assess target lesion remodelling before percutaneous coronary intervention. PR was defined as the ratio of the external elastic membrane cross-sectional area at the target lesion to that of at the proximal reference of >1.05, and intermediate or negative remodelling (IR/NR) was defined as that of ≤1.05. Major adverse cardiac event (MACE) was defined as a composite of death, ACS, and target lesion revascularization. During the follow-up (median 5.8 years), MACE-free survival was significantly lower in the PR group than that in the IR/NR group (log-rank, P = 0.005). Survival and ACS-free survival were also significantly lower in the PR group than that in the IR/NR group (log-rank, both P = 0.04). By multivariable Cox regression analysis, PR (hazard ratio = 2.4, P = 0.02) and diabetes (hazard ratio = 1.9, P = 0.03) were independent predictors of MACE.

CONCLUSION

Culprit lesion PR was associated with a poor long-term prognosis in patients with ACS. PR may be a marker of vulnerable patients.

Plaque characteristics of thin-cap fibroatheroma evaluated by OCT and IVUS

OBJECTIVES

The purpose of this study was to assess plaque characteristics of optical coherence tomography (OCT)-derived thin-cap fibroatheroma (TCFA) by integrated backscatter intravascular ultrasound (IB-IVUS).

BACKGROUND

Radiofrequency signal-derived IVUS tissue characterization technology has become clinically available and provided objective and quantitative plaque characteristics of the coronary vessel wall. Integrated backscatter IVUS is one of the tissue characterization methods that can possibly provide quantitative plaque characteristics of the OCT-derived TCFA.

METHODS

Eighty-one coronary lesions with plaque burden >40% were selected and analyzed with both IB-IVUS and OCT. The OCT-derived TCFA was defined as a presence of thin fibrous cap (<65 μm) overlying a signal-poor lesion with diffuse border representing a lipid-rich plaque. By conventional gray-scale IVUS, external elastic membrane (EEM) cross-sectional area (CSA), lumen CSA, plaque plus media (P+M) CSA, plaque burden and remodeling index were measured. By IB-IVUS, plaque characteristics were further classified as fibrosis, dense fibrosis, calcification, or lipid pool.

RESULTS

Optical coherence tomography identified 40 TCFAs (49%) and 41 non-TCFAs. The EEM CSA, P+M CSA, plaque burden, and remodeling index were significantly larger in OCT-derived TCFA than non-TCFA. By IB-IVUS, percentage lipid pool area (= lipid pool area/P+M CSA × 100) was significantly higher (62.4 ± 12.8% vs. 38.4 ± 13.1%, p<0.0001) and percentage fibrosis area (= fibrosis area/P+M CSA × 100) was significantly lower (34.6 ± 11.4% vs. 50.5 ± 8.7%, p<0.0001) in OCT-derived TCFA than non-TCFA. By receiver-operator characteristic curve analysis, percentage lipid pool area ≥55%, percentage fibrosis area ≤41%, and remodeling index ≥1.0 were predictors of OCT-derived TCFA.

CONCLUSIONS

The OCT-derived TCFA had larger plaque burden and positive remodeling with predominant lipid component and less fibrous plaque assessed by IB-IVUS.

Relationship Between Arterial and Fibrous Cap Remodeling

Background—

Positive arterial remodeling and thin fibrous cap are characteristics of rupture-prone or vulnerable plaque. The natural course of the fibrous cap thickness and the relationship between serial arterial remodeling and changes in fibrous cap thickness are unknown. Therefore, the purpose of this study was to evaluate the relationship between changes in fibrous cap thickness and arterial remodeling by using optical coherence tomography (OCT) and intravascular ultrasound (IVUS) during 6-month follow-up.

Methods and Results—

Both IVUS and OCT examinations were performed on 108 vessels from 36 patients with ischemic heart disease who underwent percutaneous coronary intervention. Fifty-eight fibroatheromas were selected from 82 nonsignificant, nonculprit lesions (angiographic diameter stenosis, 25% to 75%; plaque burden, >40% by IVUS). Fibroatheroma was defined by OCT as lipid-rich plaque in >1 quadrant that has lipid. Thickness of the fibrous cap was measured by OCT. IVUS and OCT examinations were repeated at 6-month follow-up. Serial changes and relationships between IVUS indices and fibrous cap thickness were investigated. Overall, fibrous cap thickness (98.1±38.9 to 96.9±44.5 μm) as well as IVUS indices did not change significantly within 6 months. The percent changes in fibrous cap thickness correlated negatively and significantly ( r =−0.54; P <0.0001; generalized estimating equation adjusted, r =−0.42; P =0.001) with the percent changes in external elastic membrane cross-sectional area.

Conclusions—

Arterial remodeling is related to changes in fibrous cap thickness. Positive arterial remodeling is not only an adaptive process, but also related to thinning of the fibrous cap.

Effect of culprit-lesion remodeling versus plaque rupture on three-year outcome in patients with acute coronary syndrome

To investigate intravascular ultrasound predictors of long-term clinical outcome in patients with acute coronary syndrome, 94 patients with a first acute coronary syndrome with both preintervention intravascular ultrasound imaging and long-term follow-up were enrolled in this study. Remodeling index was defined as external elastic membrane cross-sectional area at the target lesion divided by that at the proximal reference. Arterial remodeling was defined as either positive (PR: remodeling index >1.05) or intermediate/negative remodeling (remodeling index < or =1.05). Clinical events were death, myocardial infarction, and target-lesion revascularization. Patients were followed up for a mean of 3 years. PR was observed in 50 (53%), and intermediate/negative remodeling, in 44 (47%). During the 3-year follow-up, there were 20 target-lesion revascularization events and 5 deaths (2 cardiac and 3 noncardiac), but no myocardial infarctions. Patients with PR showed significantly lower major adverse cardiac event (MACE; death, myocardial infarction, and target-lesion revascularization)-free survival (log-rank p = 0.03). However, patients with plaque rupture showed a nonsignificant trend toward lower MACE-free survival (p = 0.13), but there were no significant differences in MACE-free survival between those with single versus multiple plaque ruptures. Using multivariate logistic regression analysis, only culprit lesion PR was an independent predictor of MACEs (p = 0.04). In conclusion, culprit-lesion remodeling rather than the presence or absence of culprit-lesion plaque rupture was a strong predictor of long-term (3-year) clinical outcome in patients with acute coronary syndrome.

Relationship between coronary remodeling and plaque characterization in patients without clinical evidence of coronary artery disease

AIMS

The objectives of this study were: (1) to evaluate the relationship between coronary arterial remodeling assessed by intravascular ultrasound (IVUS) and plaque morphology assessed by histological examination in patients without clinical evidence of coronary artery disease and (2) to compare plaque morphology between histological examination and optical coherence tomography (OCT).

METHODS

Coronary segments (n=98) were harvested from the heart of 34 patients who died without clinical evidence of coronary artery disease. The segments with remodeling were assessed by IVUS and compared with corresponding OCT and histological images.

RESULTS

The fibrofatty plaque area was larger in lesions with expansive remodeling (ER) than in lesions with intermediate/constrictive remodeling (IR/CR) (p<0.01). Incidence of lipid containing plaque with the thickness of the fibrous cap smaller than 200 microm tended to be higher in ER than in IR/CR (34% versus 13%, p=0.10). OCT assessment of lipid containing plaque with thinner fibrous cap was achieved with 92% sensitivity and 75% specificity.

CONCLUSIONS

The fibrofatty plaque area was larger in lesions with ER than IR/CR even in patients without clinical evidence of coronary artery disease. The current capabilities of OCT are well suited for evaluation of lipid containing plaques with thinner fibrous cap.

Impact of arterial remodelling and plaque rupture on target and non-target lesion revascularisation after stent implantation in patients with acute coronary syndrome: an intravascular ultrasound study

OBJECTIVES

To investigate the impact of arterial remodelling on long-term clinical outcome after stent implantation in patients with acute coronary syndrome (ACS).

METHODS

134 patients with ACS were enrolled. External elastic membrane (EEM) cross-sectional area (CSA) and lumen CSA were measured. Plaque and media CSA was calculated as EEM minus lumen CSA. Final minimal stent area (MSA) was also measured after stenting. Positive remodelling (PR) was defined as the ratio of the EEM CSA at the target lesion to that at the proximal reference of >1.05, and intermediate or negative remodelling (IR/NR) was defined as that of < or =1.05.

RESULTS

Although final MSA was similar, target lesion revascularisation (TLR) rates at 2 years were significantly higher in patients with PR (33.7%) than in those with IR/NR (13.7%; p = 0.01). In addition, non-TLR rates were also significantly higher in patients with PR (42.2%) than in those with IR/NR (23.5%; p = 0.03). Cardiac event-free survival (for events such as death, myocardial infarction, TLR and non-TLR) was significantly lower in patients with PR than in those with IR/NR (log rank, p = 0.001). By multivariate logistic regression analysis, PR (chi2 6.57, OR 2.70; 95% CI, 1.27 to 5.78; p = 0.01) and plaque rupture (chi2 4.17, OR 2.38; 95% CI, 1.04 to 5.45; p = 0.04) were independent predictors of cardiac events.

CONCLUSION

In patients with ACS, PR and intravascular ultrasound findings that may correspond with plaque rupture predict cardiac events including both TLR and non-TLR at 2 years.

Effect of preinterventional arterial remodeling on intimal hyperplasia after implantation of a polymer-based paclitaxel-eluting stent: angiographic and IVUS study

BACKGROUND

The aim of this study was to evaluate the effect of preinterventional arterial remodeling on in-stent intimal hyperplasia (IH) after the implantation of a polymer-based paclitaxel-eluting stent.

METHODS

The study population consisted of 55 patients (61 lesions) with a de novo lesion treated with a paclitaxel-eluting stent. The lesions were divided into two groups, positive or intermediate (PR/IR), and negative remodeling (NR) groups, according to the preinterventional arterial remodeling. Angiographic and IVUS examinations were performed preintervention, postintervention and at 9 months of follow-up.

RESULTS

The remodeling index (RI) was 1.19+/-0.16 in the PR/IR group and 0.81+/-0.10 in the NR group. At follow-up, the late loss was significantly larger in the PR/IR group than in the IR group. (0.65+/-0.58 mm vs. 0.29+/-0.5 mm, p=0.017). The external elastic membrane cross-sectional area (CSA) (18.68+/-5.39 vs. 12.87+/-3.72 mm(2), p=0.000), plaque CSA (16.99+/-4.04 vs. 10.34+/-3.45 Mm(2), p=0.000) and plaque index (85.84+/-5.02 vs. 81.80+/-7.26%, p=0.048) during the preintervention period and IH volume during the follow-up were significantly larger in the PR/IR group than in the NR group (17.98+/-16.7 mm(3) vs. 4.59+/-12.4 mm(3); p<0.001). Further, the percentage of the change in the IH was also larger in the PR/IR group than in the NR group (13.49+/-11.78% vs. 4.12+/-10.76%; p=0.002). A significant positive correlation was found between the preinterventional RI and follow-up IH CSA (r=0.406, p=0.001).

CONCLUSIONS

The preinterventional arterial remodeling influenced the development of the IH after the implantation of the polymer-based paclitaxel-eluting stent which had a greater effect on reducing the IH accumulation in the lesions with preinterventional negative remodeling characteristics.

Impact of Preinterventional Arterial Remodeling on In-Stent Neointimal Hyperplasia and In-Stent Restenosis After Coronary Stent Implantation-An Intravascular Ultrasound Study-

BACKGROUND

Patterns of arterial remodeling during the course of plaque development have been shown to play an important role in both the progression of de novo atherosclerosis and in the restenotic process following coronary intervention. The aim of the present prospective study was to evaluate the effect of pre-interventional arterial remodeling on in-stent neointimal hyperplasia (NIH) and in-stent restenosis (ISR) after stenting.

METHODS AND RESULTS

Pre-interventional arterial remodeling was assessed in 85 native coronary lesions by using intravascular ultrasound (IVUS). The remodeling index (RI) was 1.09+/-0.20 in the positive remodeling (PR)/intermediate remodeling (IR) group and 0.84+/-0.12 in the negative remodeling (NR) group. The plaque plus media cross sectional area (P&M CSA) at pre-intervention and NIH CSA at follow-up in the minimal lumen CSA were significantly larger in the PR/IR group (9.2+/-2.9 mm2 vs 6.2+/-1.8 mm2, 3.3+/-1.2 mm2 vs 1.5+/-0.9 mm2; p = 0.001, p = 0.001, respectively). On 3-dimensional analysis of IVUS images at follow-up, the lumen volume was significantly smaller in the PR/IR group than that in the NR group (62+/-15 mm3 vs 75 +/-20 mm3; p = 0.001), and neointima hyperplasia volume was significantly larger in the PR/IR group than that in the NR group (46+/-15 mm3 vs 26+/-10 mm3; p = 0.001). A significant positive correlation was found between pre-interventional RI and follow-up NIH CSA (r = 0.25, p = 0.022). The incidence of ISR and repeat intervention was significantly higher in the PR/IR group (30.8% vs 18.2%, 28.8% vs 15.2%; p = 0.032, 0.035, respectively).

CONCLUSION

Measuring pre-interventional arterial remodeling patterns by IVUS may be helpful to stratify lesions at high-risk of ISR.

In-stent restenosis and lesion morphology in patients with acute myocardial infarction

We investigated the correlation between lesion morphology with preintervention intravascular ultrasound and in-stent restenosis in 72 patients with acute myocardial infarction (AMI). Multivariate logistic regression analysis showed that the presence of ruptured plaque was the only predictive factor of in-stent restenosis after primary stenting for AMI.

Predictors of vessel remodeling following directional coronary atherectomy

The purpose of this study was to clarify predictors of vessel remodeling following directional coronary atherectomy (DCA). Negative remodeling after DCA leads to restenosis. However, little is known about the predictors of the vessel remodeling. Serial IVUS was performed in 43 lesions. The vessel remodeling was defined as adaptive if vessel area at follow-up minus postprocedure vessel area was > 0 mm2, or as constrictive if < 0 mm2. Adaptive remodeling occurred in 21 (49%) lesions. Postprocedure percent plaque area was smaller in the adaptive group (32.9% +/- 5.7% vs. 45.5% +/- 8.8%; P < 0.005). At follow-up, vessel area was larger in the adaptive group. However, plaque area was similar between the two groups. As a result, lumen area was larger in the adaptive group. Multivariate analyses showed that postprocedure percent plaque area < 40% was the only predictor of adaptive remodeling (odds ratio, 6.68; P < 0.05).

Impact of pre-interventional arterial remodeling on subsequent vessel behavior after balloon angioplasty: a serial intravascular ultrasound study

OBJECTIVES

The purpose of this study was to assess the impact of pre-intervention arterial remodeling on subsequent vessel behavior following balloon angioplasty.

BACKGROUND

Positive arterial remodeling before intervention has been shown to have a negative impact on the clinical outcome after nonstented coronary interventional procedures. However, the mechanism of interventions in coronary vessel geometry over time is less well characterized.

METHODS

Serial (pre-, post- and follow-up) intravascular ultrasound analysis was performed in 46 native coronary lesions. Positive remodeling (PR) was defined as vessel area (VA) at the target lesion greater than that of average reference segments. Intermediate or negative remodeling (IR/NR) was defined as VA at the target lesion less than or equal to that of average reference segment. Remodeling index was defined as VA at the target lesion site divided by that of average references.

RESULTS

Pre-interventional PR and IR/NR were present in 21 (46%) and 25 (54%) of 46 patients, respectively. At follow-up, the change in plaque area was similar between the two groups (1.3 +/- 2.1 vs. 1.2 +/- 2.1 mm(2), p = 0.840). Lesions with PR showed a significantly smaller change in VA than those with IR/NR (-0.2 +/- 2.5 vs. 1.4 +/- 2.3 mm(2), p = 0.03). As a result, late lumen loss was significantly larger in lesions whose pre-intervention configuration exhibited PR (-1.5 +/- 1.8 vs. 0.2 +/- 1.6 mm(2), p = 0.002).

CONCLUSIONS

Lesions with PR appear to have less capacity to compensate for further plaque growth after balloon angioplasty and thus show a proportional increase in late lumen loss. This may in part explain the less favorable clinical outcomes of positively remodeled lesions.

[Prognostic value of normal coronary angiography]

Coronary angiography is the "gold standard" for coronary artery disease (CAD). It is considered either normal or subnormal without any lesion (endocoronary echography often demonstrates atheroma), or in presence of a < 50% stenosis. Nevertheless, the risk of plaque rupture is not well correlated with the degree stenosis. Despite the frequent presence of non-significant atheroma, is a normal coronarography really of a good prognosis? Between January and September 1997, 136 of 600 (22.6%) angiographies were considered as normal. The indications were: "CAD suspicion" (n = 77), "preoperative angiography of valvulopathy" (n = 38), and "angioplasty control" (n = 22). The arteries were strictly normal for 86 patients (63%) and a < 50% stenosis was found in 50 patients (37%); 108 patients (80.1%) were followed for 18 +/- 3 months: eight non coronary deaths were reported: four postoperative deaths in "valvular group", two pulmonary embolisms and two pulmonary neoplasm's in "CAD suspicion group". No myocardial infarction was reported and one unstable angina was documented. Despite the frequency of non-significant atheroma, an acute coronary syndrome exceptionally complicates a "normal" coronarography.

Preintervention arterial remodeling affects clinical outcome following stenting: an intravascular ultrasound study

OBJECTIVES

The study was done to elucidate the relationship between baseline arterial remodeling and clinical outcome following stenting.

BACKGROUND

The impact of preintervention arterial remodeling on subsequent vessel response and clinical outcome has been reported following nonstent coronary interventions. However, in stented segments, the impact of preintervention remodeling on clinical outcome has not been clarified.

METHODS

Preintervention remodeling was assessed in 108 native coronary lesions by using intravascular ultrasound (IVUS). Positive remodeling (PR) was defined as vessel area (VA) at the target lesion greater than that of average reference segments. Intermediate or negative remodeling (IR/NR) was defined as VA at the target lesion less than or equal to that of average reference segment. Remodeling index expressed as a continuous variable was defined as VA at the target lesion site divided by that of average reference segments.

RESULTS

Positive remodeling was present in 59 (55%) and IR/NR in 49 (45%) lesions. Although final minimal stent areas were similar (7.76 +/- 1.80 vs. 8.09 +/- 1.90 mm2, p = 0.36), target vessel revascularization (TVR) rate at nine-month follow-up was significantly higher in the PR group (22.0% vs. 4.1%, p = 0.01). By multivariate logistic regression analysis, higher remodeling index was the only independent predictor of TVR (p = 0.02).

CONCLUSIONS

Lesions with PR before intervention appear to have a worse clinical outcome following IVUS-guided stenting. Intravascular ultrasound imaging before stenting may be helpful to stratify lesions at high risk for accelerated intimal proliferation.