Angiographic changes produced by percutaneous transluminal coronary angioplasty

Management of Percutaneous Coronary Intervention Complications: Algorithms From the 2018 and 2019 Seattle Percutaneous Coronary Intervention Complications Conference

Complications of percutaneous coronary intervention (PCI) may have significant impact on patient survival and healthcare costs. PCI procedural complexity and patient risk are increasing, and operators must be prepared to recognize and treat complications, such as perforations, dissections, hemodynamic collapse, no-reflow, and entrapped equipment. Unfortunately, few resources exist to train operators in PCI complication management. Uncertainty regarding complication management could contribute to the undertreatment of patients with high-complexity coronary disease. We, therefore, coordinated the Learning From Complications: How to Be a Better Interventionalist courses to disseminate the collective experience of high-volume PCI operators with extensive experience in chronic total occlusion and high-risk PCI. From these conferences in 2018 and 2019, we developed algorithms that emphasize early recognition, effective treatment, and team-based care of PCI complications. We think that an algorithmic approach will result in a logical and systematic response to life-threatening complications. This construct may be useful for operators who plan to perform complex PCI procedures.

Management of Coronary Artery Aneurysms at the Time of Surgical Revascularization

BACKGROUND

Coronary artery aneurysms (CAAs) represent a rare pathology occurring in 1.5%-5% of routine coronary angiograms. Limited data exist on the management of CAA at the time of cardiac surgery.

MATERIALS AND METHODS

A single-institution retrospective review was performed on 53 patients who underwent cardiac surgery in the setting of atherosclerotic CAA between 1993 and 2015. Patients were stratified based on treatment strategy: exclusion and distal bypass (n = 26) versus revascularization alone (n = 27). Comparisons were made with respect to mortality, need for further/concomitant interventions, and long-term cardiac function including myocardial infarctions and congestive heart failure.

RESULTS

A total of 53 patients underwent cardiac surgery in the setting of CAA disease. Management strategies included ligation and bypass in 26 patients and distal bypass only in 27 patients (with four of the patients in this group undergoing coronary stenting across the aneurysm). There were no significant differences in patient demographics between the two groups. No significant difference was found in either 30-d (P = 0.74) or long-term mortality when exclusion of the CAA was performed compared with revascularization alone (P = 0.20). More exclusion procedures were performed earlier in the experience (median surgical date 2000), whereas revascularization alone predominated later in the experience (median surgical date 2007; P ≤ 0.001).

CONCLUSIONS

The practice of CAA exclusion, while still performed in selected cases, has largely been supplanted in patients undergoing revascularization. Exclusion does not appear to offer any advantage over isolated revascularization, supporting the current trends in managing this rare condition.

Coronary Artery Aneurysm: Evaluation, Prognosis, and Proposed Treatment Strategies

Coronary artery aneurysm is a rare disorder, which occurs in 0.3%-4.9% of patients undergoing coronary angiography. Atherosclerosis accounts for >90% of coronary artery aneurysms in adults, whereas Kawasaki disease is responsible for most cases in children. Recently, with the advent of implantation of drug-eluting stents, there are increasing reports suggesting stents causing coronary aneurysms, months or years after the procedure. The pathophysiology of coronary artery aneurysm is not completely understood but is thought to be similar to that for aneurysms of larger vessels, with the destruction of arterial media, thinning of the arterial wall, increased wall stress, and progressive dilatation of the coronary artery segment. Coronary angiography remains the gold standard tool, providing information about the size, shape, and location and is also useful for planning the strategy of surgical resection. The natural history and prognosis remain unclear. Despite the important anatomical abnormality of the coronary artery, the treatment options of coronary artery aneuryms are still poorly defined and present a therapeutic challenge. We describe four cases, which were managed differently followed by a review of the current literature and propose some treatment strategies.

Spontaneous disappearance of coronary pseudoaneurysm due to coronary artery perforation following percutaneous coronary intervention

In recent years, while therapeutic outcome after percutaneous coronary intervention is improving due to the introduction of drug-eluting stent and device development, procedure-related complications including coronary perforation may ineluctably occur though at low-frequency, even if careful manipulations are performed under IVUS guidance. Meanwhile, coronary pseudoaneurysm subsequent to coronary perforation is one of the complications at chronic phase infrequently experienced following percutaneous coronary intervention. To date, the incidence and natural history of pseudoaneurysm following coronary artery perforation remain unclear. We experienced a case with coronary pseudoaneurysm developed 2 weeks after Ellis II-type coronary artery perforation which spontaneously disappeared 4 months later. As the mechanism of disappearance, thrombotic occlusion was confirmed upon intravascular ultrasound.

Double-barrel coronary artery dissection

Coronary artery dissection is a common occurrence after percutaneous transluminal coronary angioplasty (PTCA). However, we report herein a rare case of double-barrel coronary artery dissection occurring 1 year after PTCA for stenosis in the left circumflex coronary artery. The case history and angiographic findings are reported, and relevant literature is reviewed.

Correlation of angiographic morphology immediately after coronary balloon angioplasty with coronary vasomotion late after angioplasty

BACKGROUND

Various vasomotor responses to acetylcholine have been observed after coronary angioplasty. However, the relationship between the grade of vascular injury due to balloon angioplasty and vasomotor response to acetylcholine in the chronic stage is unknown. In this study we examined the correlation between the morphology immediately after coronary angioplasty and the vasomotor response to acetylcholine 1 year after angioplasty.

METHODS

Thirty nine patients with a total of 45 coronary lesions without restenosis 1 year after angioplasty were studied. The 45 lesions were divided into two groups according to the morphology immediately after angioplasty. Group A comprised smooth-walled dilation and smooth-walled dilation with intraluminal haziness which were considered to be related to injury limited to the intima or the surface of the media. Group B comprised intraluminal and extraluminal haziness and extraluminal type dissection which were considered to be related to extensive medial injury. In the 39 patients, acetylcholine provocation test was performed.

RESULTS

Transient total occlusion of angioplasty site was induced by acetylcholine in four lesions only in Group A. Percent change in coronary diameter after acetylcholine injection relative to that after injection of isosorbide dinitrate at the angioplasty site was larger in Group A than that of Group B.

CONCLUSION

In the chronic stage, vessels with minor vascular injury exhibited a large vasomotor response to acetylcholine; conversely, the response was low in vessels with severe vascular injury by angioplasty. These observations suggest that severe vascular injury by balloon angioplasty may control coronary vasomotion in the chronic stage.

Haziness on coronary angiogram after percutaneous transluminal coronary angioplasty evaluated with angioscopy

Coronary angiograms obtained after percutaneous transluminal coronary angioplasty are often hazy due to uneven distribution of contrast medium at the angioplasty site, In this study, structural changes resulting in haziness after percutaneous transluminal coronary angioplasty were identified angioscopically. The affected coronary arteries of 35 patients who underwent successful percutaneous transluminal coronary angioplasty were examined with angioscopy. Coronary angioscopic examination of the sites subjected to percutaneous transluminal coronary angioplasty revealed large surface disruptions in 17 cases, small surface disruptions in four cases, and thrombi in 24 cases. Angiographic haziness was recognized in 24 of 35 patients after percutaneous transluminal coronary angioplasty. Haziness on angiography was more significant in patients who exhibited large surface disruption (88% vs 50%, p < 0.05), and was significantly greater in patients who exhibited white thrombus (100% vs 56%, p<0.05). Moreover, it appears that percutaneous transluminal coronary angioplasty-induced large surface disruption and white thrombus likely play an important role in increasing haziness.

Angiographic classification of coronary dissections after plain old balloon angioplasty for prediction of regression at follow-up

Coronary dissection after plain old balloon angioplasty often shows regression during follow-up. This study sought to determine whether we can predict such phenomenon angiographically. We analyzed 64 patients with 71 type B-D coronary dissections determined by the National, Heart, Lung, and Blood Institute (NHLBI) criteria. Regression was considered present when minimal lumen diameter increased by more than 0.3 mm during follow-up. Dissections were divided into subgroups using the NHLBI criteria and our classification in which type a and b dissections were characterized by the width of a dissection lumen exceeding one quarter of the reference diameter with the outer edge of the dissection lumen within the boundary of reference in type a and beyond it in type b. In type c and type d dissections, the width of the dissection lumen was within one quarter of the reference with its outer edge within the boundary of reference in type c and beyond it in type d. Type e dissection had a protruding flap or spiral appearance. Regression was recognized in 23.9%. The distribution of dissection types was similar in the groups with and without regression by the NHLBI criteria, but type c dissection had regression more frequently than the other types of coronary dissections (p<0.001) using our classification.

Beneficial application of quantitative coronary angiography (edge detection algorithm) in analysis of dissected coronary arteries to predict long-term patency

The present study evaluated the application of quantitative coronary angiography (edge detection algorithm) for the analysis of coronary dissection lesions after balloon angioplasty. Acute and late results were obtained by the edge detection algorithm in 60 patients with 66 dissected lesions (NHLBI types B-C). The edge detection algorithm delineated the border of the true lumen in 32 lesions (group with automated analysis alone, 48.5%) and included the dissection cap in the analysis in 34 lesions in which manual editing was adjuncted (group with manual editing, 51.5%). In both groups, the minimal lumen diameter after balloon angioplasty obtained by initial automated analysis was correlated to that obtained at the 5.3-month follow-up similarly (r=0.554, p=0.0010 for the group with automated analysis alone and r=0.613, p=0.0001 after automated analysis for the group with manual editing). However, additional manual editing reduced the correlation coefficient (r=0.240, p=0.1707) in the latter group. Thus, in terms of predicting long-term patency, it is reasonable to let the edge detection algorithm decide the measurements in types B and C dissected lesions.

Intravascular ultrasonography in the evaluation of results of coronary angioplasty and stenting

The main advantage of intravascular ultrasonography (IVUS) over angiography in assessing the effect of coronary interventions is the ability of IVUS to directly visualize the vessel wall. IVUS often reveals a high residual plaque burden after angiographically successful angioplasty, and this can motivate the operator to use additional, more aggressive measures in an attempt to increase lumen dimensions. Studies using IVUS imaging before and after balloon angioplasty have shown that luminal gain after percutaneous transluminal coronary angioplasty (PTCA) results from a combination of plaque reduction and vessel wall stretch. Minimal luminal area and residual area stenosis after PTCA and stent deployment, as measured by IVUS, have been shown to be predictors of restenosis. IVUS studies have pointed to vessel shrinkage, not intimal hyperplasia, as the main mechanism of restenosis after PTCA. IVUS guidance of stent deployment has often revealed inadequate stent expansion despite optimal results on angiography, leading to high-pressure stent deployment with significant additional luminal gain. Restenosis rates may be lower with IVUS-guided stent deployment.

Percutaneous closure of a coronary aneurysm with a vein-coated stent

Coronary artery aneurysm is a rare but recognized complication following percutaneous intervention. We report the formation of such an aneurysm after recanalization with Excimer laser wire of a chronic totally occluded left anterior descending coronary artery and stent implantation and its subsequent treatment using an autologous vein graft-coated stent.

Coronary aneurysm after bailout stent implantation: diagnosis of a false lumen with intravascular ultrasound

This case report describes the intravascular ultrasound (IVUS) evaluation of a coronary artery aneurysm, developed in a stented segment within 6 mo after bailout stenting. Analysis of the IVUS images provides in vivo insights in the vessel-remodeling process after mechanical injury. The proximal entrance of the false lumen could be clearly visualized as well as the relationship between the stent struts, neolumen, and vessel wall. The discussion is focused on the options for management of such patients.

Intravascular ultrasound assessment of the prevalence and causes of angiographic "haziness" following high-pressure coronary stenting

Haziness at sites of balloon angioplasty is believed to represent plaque fractures or platelet deposition. The etiology of haziness adjacent to coronary stents remains uncertain. This study examines the prevalence and etiology of "peri-stent" haziness following high-pressure deployment. Consecutive patients undergoing coronary stenting and intravascular ultrasound imaging were included. Haziness was defined as nonhomogeneous contrast density and/or indistinct vessel borders by consensus of 2 observers. Patients were excluded if angiography revealed an obvious cause of haziness (thrombus, dissection). Matched control segments without haziness were selected for comparison. The most diseased site within the reference segment was identified by ultrasound. Lumen and plaque areas, percent plaque area, and plaque echo density were assessed. Haziness was identified within 31 segments in 30 patients (15% of 201 angiograms examined). At hazy sites, ultrasound revealed a large percent plaque area in 15, dissections in 14, and near-normal findings in 2 segments. In the absence of dissection, percent plaque area and lumen area step-down from the stent to the diseased reference were greater than controls (percent plaque area 64 +/- 12% vs 56 +/- 10%, p = 0.04 and lumen step-down 35 +/- 20% vs 13 +/- 25%, p = 0.006). With dissections, percent plaque area and lumen step-down were not different from controls (p = 0.13 and 0.30, respectively), but underlying plaques were more frequently echolucent (64% vs 23%, p = 0.02). Thus, in this study, peri-stent haziness was evident in 15% of patients after high-pressure coronary stent deployment. Etiologies identified by intravascular ultrasound included unrecognized reference plaque and angiographically occult dissections.

Coronary artery aneurysm: a review

Coronary artery aneurysm is defined as coronary dilatation which exceeds the diameter of normal adjacent segments or the diameter of the patient's largest coronary vessel by 1.5 times. This is an uncommon disease which has been diagnosed with increasing frequency since the advent of coronary angiography. The incidence varies from 1.5% to 5% with male dominance and a predilection for the right coronary artery. Atherosclerosis accounts for 50% of coronary aneurysms in adults. Reported complications include thrombosis and distal embolization, rupture and vasospasm. The natural history and prognosis remains obscure. Controversies persist regarding the use of surgical or medical management. The authors recommend surgery based on the severity of associated coronary stenosis rather than the mere presence of aneurysm. Medical therapy is indicated for the majority of patients and consists of antiplatelet and anticoagulant medication.

Coronary artery and saphenous vein graft remodeling: a review of histologic findings after various interventional procedures--Part IV

Catheter balloon angioplasty is a well accepted form of nonsurgical treatment of acutely and chronically obstructed coronary artery vessels. It is also the centerpiece for various new intervention techniques. Their morphologic effects on the site of obstruction has been termed "remodeling." Part IV of this six-part series focuses on morphologic correlates of coronary angiographic patterns of remodeling after balloon angioplasty and discusses effects of angioplasty on adjacent, nondilated vessels.

Surgical management of instrumentation-induced coronary artery dissection

The mechanism of instrument-induced coronary artery dissections (IICDs) is briefly presented. Depending on the coronary anatomy, three different situations that may occur are distinguished: (1) major coronary branches between the site of dissection and planned anastomosis; (2) no important collaterals at the same location; and (3) perforation of the coronary artery. Surgical methods applicable to each for the correction of these situations is presented.

Early and late quantitative angiographic results of vein graft lesions treated by excimer laser with adjunctive balloon angioplasty

BACKGROUND

Percutaneous excimer laser coronary angioplasty (PELCA) has been approved for treatment of diseased saphenous vein bypass grafts. However, detailed and complete quantitative angiographic analysis of immediate procedural and late follow-up results has not been performed.

METHODS AND RESULTS

PELCA using the CVX-300 excimer laser system was performed in 125 bypass lesions (mean graft age, 96 +/- 53 months; range, 2 to 240 months) in 106 consecutive patients at eight centers. Quantitative analyses of the procedural and follow-up angiograms were done with the Cardiac Measurement System. Stand-alone PELCA was done in 21 lesions (17%). Lesions were located at the ostium (20%), body (67%), or distal anastomosis (13%). The graft reference diameter was 3.26 +/- 0.79 mm (mean +/- SD). Minimal lumen diameter increased from 1.09 +/- 0.52 mm before treatment to 1.61 +/- 0.69 mm after laser and 2.18 +/- 0.63 mm after adjunctive balloon dilation (P < .001) but had declined at follow-up to 1.40 +/- 1.17 mm. Dissections were evident in 45% of lesions after laser treatment (types A and B, 27%; types C through F, 18%), including 7% occlusions. Angiographic success (< or = 50% diameter stenosis [% DS]) was 54% after laser and 91% after adjunctive PTCA, with an overall clinical success rate of 89%. In-hospital complications were death, 0.9%; myocardial infarction (Q-wave and non-Q-wave), 4.5%; and bypass surgery, 0.9%. Independent predictors of % DS after laser were reference diameter, lesion length, and minimal lumen diameter before laser. At angiographic follow-up in 83% of eligible patients, the restenosis rate per lesion (DS > 50%) was 52%, including 23 occlusions (24%). The only independent predictor of increased % DS at follow-up was lesion symmetry. Logistic regression indicated that smaller reference diameter was an independent predictor of late occlusion. Overall 1-year mortality was 8.6%. Actuarial event-free survival (freedom from death, myocardial infarction, bypass surgery, or target vessel percutaneous transluminal coronary angioplasty) was 48.2% at 1 year.

CONCLUSIONS

Excimer laser angioplasty with adjunctive balloon angioplasty can be safely and successfully performed in diseased, old saphenous vein bypass graft lesions considered at high risk for reintervention. The extent of laser ablation remains limited by the diameter and effectiveness of the catheters. Late restenosis and, in particular, total occlusion mitigate the early benefits of the procedure. Other approaches such as the routine use of additional anticoagulation (eg, warfarin) should be considered to reduce the risk of late occlusions and restenosis after laser angioplasty of bypass grafts.

Coronary artery aneurysms after angioplasty and atherectomy

Coronary artery aneurysm formation after percutaneous transluminal coronary angioplasty and directional coronary atherectomy is unusual. We report the case of a left anterior descending coronary artery aneurysm that formed in such a patient. The left anterior descending coronary artery was bypassed and the aneurysm was plicated with the aid of coronary angioscopy. The English-language medical literature on the topic of coronary artery aneurysms is reviewed.

Directional low-pass filtering for improved accuracy and reproducibility of stenosis quantification in coronary arteriograms

Considers the quantification of percent diameter stenosis in digital coronary arteriograms of low spatial resolution. To improve accuracy and reproducibility an edge-preserving smoothing method, called the directional low-pass filter (DLF), was developed to suppress quantum noise by averaging image intensity in a direction parallel to the vessel border. Accuracy of stenosis quantification was assessed by using stenosis phantoms. The standard error of the estimate (SEE) was 0.76 pixel-length (p) without spatial filtering and further reduced to 0.50 p by DLF; the average deviation as a measure of the regularity of border definition was also reduced by DLF from 1.00 to 0.68 p (n=50, P<0.001). It was shown that the DLF outperformed the conventional moving average filter and median filter. Reproducibility in terms of intraframe variability was assessed by using coronary arteriograms obtained from 10 patients. Intraframe variability of the percent stenosis measurements was reduced from 3.5% to 2.9% by DLF (n=10, P<0.005). An analysis of variance showed, however, that the interframe variability cannot be reduced by any of the spatial filters under investigation. The result of this study has provided a guideline for angiographically based quantification of percent stenosis under limited imaging resolution and suggests a new method for improving accuracy and reproducibility by directional low-pass filtering.

Digital angiographic assessment of the physiological changes to the regional microcirculation induced by successful coronary angioplasty

BACKGROUND

Impulse response analysis of digital coronary angiographic images calculates a parameter known as the mean transit time of the microcirculation (Tmicro). This has been shown to accurately assess the regional microcirculatory response to proximal stenosis in relation to flow. Our goal was to apply impulse response analysis to patients undergoing successful angioplasty and to quantify the induced physiological changes with respect to quantitative angiographic measurements of stenosis dimensions.

METHODS AND RESULTS

We studied 24 patients before and after successful single-vessel percutaneous transluminal coronary angioplasty (PTCA). Minimal luminal stenosis area was increased from 0.9 +/- 0.6 before PTCA to 4.1 +/- 1.3 mm2 after PTCA (P < .0001). In all patients this was accompanied by an increase in the inverse of Tmicro (Tmicro-1), from 8.5 +/- 3.0 to 26.5 +/- 9.0 min-1 (P < .0001) with a linear correlation between Tmicro-1 and minimal luminal stenosis area (r = .73; SEE = 7.74). Stenosis flow reserve, estimated by integration of stenosis dimensions, increased in all patients from 1.8 +/- 1.0 to 4.5 +/- 0.4 after PTCA (P < .01). A comparison of Tmicro-1 with stenosis flow reserve revealed a nonlinear relation. In 16 patients undergoing PTCA of the left anterior descending or circumflex artery, contrast injections into the left main stem allowed simultaneous measurements of Tmicro-1 in the adjacent, nonstenotic artery. Adjacent artery Tmicro-1 did not change after PTCA (25.8 +/- 6.2 compared with 25.6 +/- 6.8 min-1 before PTCA; P = NS); moreover, Tmicro-1 of the dilated artery measured after PTCA was equivalent to the nonstenotic adjacent artery, indicating normalization of microcirculatory responses.

CONCLUSIONS

These data suggest that Tmicro-1 determined by digital angiographic impulse response analysis of a single contrast injection under resting flow conditions may be a practical method to assess the regional microcirculatory response to changes in stenosis severity effected by coronary angioplasty.

Coronary embolization after balloon angioplasty or thrombolytic therapy: an autopsy study of 32 cases

OBJECTIVES

This study was undertaken to examine the nature, extent and clinical relevance of coronary embolism after balloon angioplasty or thrombolytic therapy, or both.

BACKGROUND

Histopathologic documentation of postinterventional coronary embolization has been reported in only 10 patients from five studies.

METHODS

This retrospective autopsy-based study included 32 patients, treated with balloon angioplasty or thrombolysis, or both, who died within 3 weeks of the procedure and underwent autopsy at the Mayo Clinic. Clinical variables included patient age and gender, artery treated, site and type of obstruction, type of intervention, success of the procedure, and postprocedural changes in the electrocardiogram (ECG), cardiac enzymes and hemodynamic status. Histopathologic variables included characteristics of treated plaques, acutely infarcted myocardium and coronary microemboli. Associations between microemboli and clinical and microscopic factors were evaluated by t tests and simple and multiple linear regression.

RESULTS

Emboli were observed in 26 (81%) of the 32 patients. Among 83 emboli, 95% were thrombotic or atheromatous. The presence of microemboli was associated statistically with the development of postprocedural infarct extension, new myocardial infarction or new ECG abnormalities. Moreover, the greatest number of microemboli were associated with intervention in the left anterior descending coronary artery, multiple interventional sites, postprocedural medial dissection and plaque rupture or extrusion.

CONCLUSIONS

Among patients undergoing balloon angioplasty or thrombolytic therapy who die and undergo autopsy, coronary microemboli occur in a substantial percent. The frequency in survivors is unknown. However, in living patients who develop acute myocardial ischemia or new ECG abnormalities after these interventions, coronary microembolization should be considered a potential cause.

Southwestern internal medicine conference: restenosis: the Achilles heel of coronary angioplasty

Percutaneous transluminal coronary angioplasty has become the treatment of choice for many patients with symptomatic coronary artery disease. Increased experience with the procedure and improvements in equipment have resulted in high initial success rates; however, a significant number of patients develop restenosis. Insights into the pathophysiologic mechanisms of restenosis have led to the use of various pharmacologic agents and devices to prevent its occurrence. Although many have been successful in decreasing the incidence of restenosis in animal studies, none has yet proven successful in decreasing the incidence of restenosis in humans. Newer approaches and novel therapies are needed to prevent restenosis after percutaneous transluminal coronary angioplasty.

Angiographic-pathologic correlations after elective percutaneous transluminal coronary angioplasty

BACKGROUND

The local effect of coronary angioplasty is evaluated on the basis of postangioplasty angiograms. Smooth-walled dilation is considered to represent minimal or no injury, whereas intraluminal haziness corresponds with wall laceration. This study correlates the preangioplasty and postangioplasty angiograms with the histopathology of the target sites.

METHODS AND RESULTS

The study includes 12 patients, each undergoing an elective procedure, and covers 19 angioplasty sites. Smooth-walled dilation and intraluminal haziness were not mutually exclusive. The angiograms were interpreted as smooth-walled dilation (n = 3), smooth-walled dilation with intraluminal haziness (n = 4), intraluminal and extraluminal haziness (n = 5), extraluminal dissection (n = 5), spiraltype dissection (n = 1), and aneurysm (n = 1). The histology of the arterial segments revealed wall laceration in all. Smooth-walled dilation without intraluminal haziness correlated with laceration limited to the intima in two, but with medial injury in one. Smooth-walled dilation with intraluminal haziness correlated with laceration limited to the intima in two and with medial injury in two. Intraluminal and extraluminal haziness corresponded with extensive laceration with deep involvement of the media in each. Extraluminal dissection correlated with a dissection along the shoulder area of the plaque, creating a broad-based flap. The spiral-type dissection corresponded with a true dissection into the plaque-free media. The aneurysm correlated with partial washout of an atherosclerotic plaque.

CONCLUSIONS

The angiographic image of intraluminal and extraluminal haziness indicates extensive medial laceration. Smooth-walled dilation, with or without intraluminal haziness, is not a reliable indicator. The study emphasizes the need to reconsider the interpretations of postangioplasty coronary angiograms.

Detailed angiographic analysis of high-speed mechanical rotational atherectomy in human coronary arteries

BACKGROUND

Several types of atherectomy devices have been developed recently for treatment of patients with ischemic heart disease.

METHODS AND RESULTS

Mechanical rotational atherectomy (MRA) using a high-speed rotational burr (Rotablator) was performed on 116 lesions in 104 patients. MRA alone was performed in 27 lesions (23%), and conventional balloon angioplasty (PTCA) was performed after MRA in 89 lesions (77%). Diameter stenosis decreased from 70 +/- 13% before MRA to 54 +/- 23% after MRA, and the final diameter stenosis (after MRA alone or with adjunctive PTCA) was 30 +/- 20% (P < .001). Minimal lumen diameter increased from 1.0 +/- 0.5 mm before MRA to 1.4 +/- 0.7 mm after MRA, and the final minimal lumen diameter was 2.3 +/- 0.7 mm (P < .001). MRA resulted in a decrease in diameter stenosis of 20% or more in 44% of lesions, and the final diameter stenosis (after MRA alone or after PTCA) was less than 50% in 75% of lesions. Considering the small diameter of available burrs, the magnitude of lumen enlargement was equal to 91% of the burr diameter, and only 9% of the burr diameter was "lost" due to elastic recoil or spasm. These angiographic results were obtained despite the presence of complex lesion morphology, including the presence of calcification in 17% of lesions and ostial location in 26% of lesions. Significant angiographic complications included abrupt closure (13 lesions, 11.2%), no reflow (8 lesions, 7%), severe coronary vasospasm (16 lesions, 13.8%), and guide wire fracture (3 lesions, 2.7%). There were no coronary artery perforations. Adjunctive therapy, including salvage PTCA, thrombolytic agents, and vasodilators, was successful in treating angiographic complications in 42 of 49 lesions (86%). Clinical complications included Q-wave myocardial infarction (5 patients, 4.8%), non-Q-wave myocardial infarction (3 patients, 2.9%), femoral vascular injury requiring surgery (3 patients, 2.9%) or blood transfusion (8 patients, 7.7%), abrupt closure requiring emergency bypass graft surgery (2 patients, 1.9%), and in-hospital death (1 patient, 1.0%). Angiographic follow-up (mean follow-up interval, 5.0 +/- 2.0 months) was available in 84% of successfully treated patients and revealed a restenosis rate of 51%, defined as a residual diameter stenosis of more than 50%. There was no significant difference in restenosis rates between de novo lesions (50%) and restenosis (54%) lesions.

CONCLUSIONS

These data suggest that for the treatment of most coronary stenoses, PTCA is required after MRA to achieve satisfactory lumen enlargement or to salvage complications. Angiographic complications appear to be more common after MRA, and salvage PTCA often is required to manage these device-induced complications. The combination of MRA and PTCA does not prevent restenosis.

Classification of morphologic effects of percutaneous transluminal coronary angioplasty assessed by intravascular ultrasound

The aim of this study was the assessment and classification of the morphologic effects of percutaneous transluminal angioplasty (PTCA) by intravascular ultrasound (IU). Fifty-eight patients were examined immediately after PTCA with a 4.8Fr, 20 MHz rotational tip IU system. In 10 patients (17%), IU images could not be analyzed due to failure of the imaging system or poor image quality. In 48 patients (83%; 40 men and 8 women, aged 55 +/- 9 years), IU images of 48 PTCA segments, as well as 41 distal and 44 proximal sites, were analyzed. The left anterior descending artery was studied in 30 patients, the right coronary artery in 17 and the left main coronary artery in 1. Calcium was present in 32 of 48 PTCA segments (67%). Plaque morphology was concentric in 18 patients (38%) and eccentric in 30 (62%). Seven distinct morphologic patterns were observed. In concentric plaques, plaque compression without significant wall alterations (type 1) was found in 2 patients (4%), superficial tears within the plaque (type 2) in 1 (2%) and deep tears (type 3) in 8 (17%). Deep tearing associated with submedial or subintimal dissection (type 4) was found in 2 patients (4%). Dissection between plaque and vessel wall without noticeable intimal tearing (type 5) was the most common morphology (n = 15; 31%) and occurred in concentric and eccentric plaques. In eccentric plaques, no significant tearing of the plaque (type 6) was found in 6 patients (13%), and tearing of the plaque close to its base with dissection (type 7) in 14 (29%).(ABSTRACT TRUNCATED AT 250 WORDS)

Relation of deep arterial resection and coronary artery aneurysms after directional coronary atherectomy

OBJECTIVES

The aims of this study were to document the frequency of coronary artery aneurysm formation in patients undergoing directional coronary atherectomy and to determine the relation of such aneurysms to the depth of arterial resection.

BACKGROUND

Deep arterial injury is relatively frequent with the use of directional coronary atherectomy, but the potential for subsequent coronary artery aneurysm formation is unknown.

METHODS

Results in a consecutive series of 64 successfully treated patients (a total of 69 lesions; mean angiographic follow-up at 5 months) treated with directional coronary atherectomy were retrospectively analyzed with use of quantitative angiographic and histologic data.

RESULTS

Coronary aneurysms (ratio of dilated vessel segment to the adjacent reference segment > 1.2:1) occurred in seven patients (10%). The only significant clinical correlate of aneurysm formation was a relatively shorter duration of angina. There were no significant preprocedural angiographic predictors of aneurysms, although 6 (86%) of the 7 aneurysmal lesions arose from restenosis lesions compared with 30 (48%) of 62 lesions with no subsequent aneurysm development (p = 0.06). Histopathologic examination of 414 specimens from 68 treated lesions showed no significant difference in the occurrence of subintimal resection (media +/- adventitia) between those with and without subsequent aneurysm (29% vs. 22%). Media alone was found in 14% of specimens from lesions that later became aneurysmal versus 15% of those that did not; adventitial resection was found in 14% and 7% of specimens, respectively (p = 0.08), with relatively more adventitia per specimen from those with aneurysm (55% vs. 30% without aneurysm, p = 0.08).

CONCLUSIONS

Aneurysms occur relatively frequently after directional coronary atherectomy. Although there was no statistically significant correlation with the depth of arterial resection, the evidence from this study suggests that the role of adventitial resection in the occurrence of late aneurysm development should be explored further.

Left main coronary artery aneurysm following percutaneous transluminal angioplasty: a report of a case and review of the literature

Since its introduction in 1977, the number of PTCAs and its indications have grown. Along with more frequent usage, newer complications have been reported. Aneurysm of left main coronary artery is rare. This report describes the formation of a new non-obstructing aneurysm in the left main coronary artery after PTCA of left circumflex artery. The patient has had 7 yr of follow-up with a benign clinical course.

Clinical angiographic and histologic correlates of ectasia after directional coronary atherectomy

Directional coronary atherectomy can cause ectasia (final area stenosis less than 0%), presumably due to an excision deeper than the angiographically "normal" arterial lumen. In a multicenter series in which quantitative coronary arteriography was performed after directional atherectomy in 382 lesions (372 patients), ectasia after atherectomy occurred in 50 (13%) lesions. By univariate analysis, ectasia was seen more often within the circumflex coronary artery (p = 0.008), in complex, probably thrombus-containing lesions (p = 0.015), and with higher device:artery ratios (p less than 0.001). Ectasia occurred less often in lesions within the right coronary artery (p = 0.008). Histologic analysis demonstrated adventitia or media, or both, in all patients with angiographic ectasia. Repeat angiography was performed in 188 of 271 eligible patients (69%) 6.1 +/- 2.4 months after atherectomy. Restenosis, defined as a follow-up area stenosis greater than or equal to 75%, was present in 50% of patients without procedural ectasia and in 70% of patients with marked ectasia (residual area stenosis less than -20%; p = 0.12). It is concluded that excision beyond the normal arterial lumen may occur after directional coronary atherectomy, related, in part, to angiographic and procedural features noted at the time of atherectomy. Restenosis tends to occur more often in patients with marked ectasia after coronary atherectomy.

A biological basis for re-stenosis after percutaneous transluminal angioplasty: possible underlying mechanisms

Intravascular catheterization is a commonly used diagnostic tool and percutaneous transluminal angioplasty is used to dilate stenosed blood vessels. Although these techniques are very successful diagnostically and therapeutically they may precipitate a number of acute and chronic complications. Chronic intimal changes following balloon angioplasty can result in re-stenosis. Intimal hyperplasia can be a long-term complication of both diagnostic and interventional vascular catheterization. This article details these long-term structural changes, specifically relating experimental in vivo and in vitro changes to those seen clinically.

Preangioplasty complicated coronary stenosis morphology as a predictor of restenosis

To assess whether complicated preangioplasty coronary stenosis morphology is associated with restenosis, 41 patients (47 stenoses) who underwent repeat angiography 6 to 8 months after percutaneous transluminal coronary angioplasty (PTCA) were studied. Stenosis diameter and morphology were assessed by computerized quantitative coronary angiography before and immediately after PTCA and at follow-up angiography. Before PTCA 18 stenoses were concentric (symmetric narrowings with smooth borders), 12 were eccentric (asymmetric narrowings with smooth borders), and 17 were complicated (asymmetric with rough borders and overhanging edges). Restenosis occurred in 18 lesions: two (11%) concentric, four (33%) eccentric, and 12 (70%) complicated (p less than 0.05), whereas 29 lesions remained unchanged. Stenosis diameter before and immediately after PTCA was not significantly different in the 18 patients with and the 23 patients without restenosis. Follow-up angiograms showed that 11 (61%) stenoses in the group with restenosis and 18 (63%) in the group without restenosis had morphology similar to that before PTCA. Restenosis occurred in seven (30%) patients who initially had chronic stable angina and in 11 (61%) who were first seen with unstable angina (p less than 0.05). In patients with stable angina 1 of 13 concentric stenoses, two of eight eccentric stenoses, and four of five complicated lesions restenosed. In patients with unstable angina one of five concentric, two of four eccentric, and 8 of 12 complicated lesions had restenosis. Stenoses that were complicated before PTCA tended to adopt an irregular morphology if they recurred, whereas concentric stenoses rarely occurred.(ABSTRACT TRUNCATED AT 250 WORDS)

Delayed coronary occlusion following primary successful angioplasty: management and outcome

The treatment of delayed coronary occlusion after primary successful percutaneous transluminal coronary angioplasty (PTCA) is more difficult because surgical standby is often not available. The purpose of this study was to assess the therapeutic approaches and outcome of patients with delayed coronary occlusion from 30 to 180 minutes after successful PTCA. A delayed occlusion occurred in 18 (0.9%) (61 +/- 11 years; male n = 14, female n = 4) out of 2065 consecutive patients after PTCA. In 11 patients the dilated stenoses were located in the left descending artery, while seven patients had the stenosis in the right coronary artery. Twelve patients had unstable or postinfarction angina. The time interval between completion of PTCA and the onset of chest pain was 64 +/- 39 minutes. Immediate i.v. nitroglycerin resulted in no relief of the symptoms in any patient. One patient was operated upon at once, and one was given i.v. thrombolysis resulting in pain relief and reversal of ECG changes. The remaining 16 patients returned initially to the catheterization laboratory, where the occluded vessels were opened by mechanical recanalization. Three of them remained in stable condition. Due to impending reocclusion surgery was necessary in four patients and thrombolysis was performed in nine. After thrombolysis the vessel remained open in four patients. The other five needed bypass surgery on the day of PTCA. Myocardial infarction developed in nine patients (maximal CK 673 +/- 488 units/l). In conclusion, delayed occlusion after successful PTCA is a rare complication occurring primarily in patients with unstable angina. Mechanical recanalization opened the occluded vessel in most patients, and myocardial infarction was prevented in 50%.

Cardiac phase-related variability of border detection or densitometric quantitation of postangioplasty lumens

We applied an automated computer program capable of simultaneous geometric (through border detection) and densitometric quantitation of digital angiograms for evaluation of the results of percutaneous transluminal coronary angioplasty (PTCA) in different phases of the same cardiac cycle. Digital subtraction coronary angiograms (DSA) of 28 patients who had undergone PTCA to a total of 30 lesions, were analyzed in diastole, in systole, and in the middle of the cardiac cycle to test the variability in coronary quantitation resulting from random frame selection relative to cardiac phase. Before PTCA there was a low degree of variation between measurements obtained from the same lesion in different phases of the cardiac cycle, in both geometric (coefficient of variation between cardiac phases = 4.2%) and densitometric (coefficient of variation between cardiac phases = 5.1%) quantitation. After PTCA, however, there was a wider variation of values in different cardiac phases, which predominated in the densitometric measurements (coefficient of variation between cardiac phases = 33.6%, compared to 20.6% for geometric measurements). There was less agreement between different post-PTCA phases in densitometry, and discrepancies as large as 47% could occur in densitometric evaluation of the stenotic areas when different phases of the cycle were used. We concluded that border detection or densitometric quantitation of the postangioplasty lumens is subject to greater variation resulting from random frame selection relative to cardiac phase, as compared to preangioplasty assessment. This variation predominates in densitometric quantitation, which seems to be dependent not only on the radiographic projection but also on the cardiac phase. The usefulness of densitometric techniques for the evaluation of PTCA results appears to be questionable.

Coronary atherectomy. Clinical, angiographic, and histological findings and observations regarding potential mechanisms

Between August 5, 1988 and August 1, 1989, we attempted percutaneous directional coronary atherectomy of 76 lesions, including 42 primary lesions and 34 restenosis lesions that developed after one or more prior interventions. The procedure was successful in 67 lesions (88%), with a decrease in diameter stenosis from 80 +/- 11% to 5 +/- 15% after atherectomy (p less than 0.01). One or more complications occurred in six patients (9%), including non-Q wave myocardial infarction (three patients, 4.5%), femoral arterial injury requiring surgical repair (two patients, 3%), and proximal dissection leading to emergency bypass surgery (one patient, 1.5%). Despite these favorable acute results, the 6-month lesion restenosis rate was 30% by life-table analysis. Light microscopy of retrieved tissue revealed atherosclerotic plaque in 94%, media in 67%, and adventitia in 27%. Intimal proliferation was present in 97% of the restenosis lesions but was also evident in 33% of primary lesions. Tissue weight from 27 lesions averaged 18.5 mg (range, 5.8-45.1 mg), which is not adequate to explain the entire angiographic improvement. Thus, part of the improvement in lumen diameter appears to be due to mechanical dilatation rather than to tissue removal alone. Atherectomy can predictably treat selected coronary lesions with overall safety comparable to that of conventional balloon angioplasty, although the procedure as currently performed does not derive all of its benefit from tissue removal and does not appear to prevent restenosis.

Is the residual translesional pressure gradient useful to predict regional myocardial perfusion after percutaneous transluminal coronary angioplasty?

Routine assessment of the severity of a coronary artery lesion with coronary cineangiography is limited by its variability and poor correlation with blood flow and postmortem findings. In this investigation, we compared the usefulness of the final coronary artery translesional pressure gradient and the final angiographic coronary percent stenosis to assess immediate percutaneous transluminal coronary angioplasty (PTCA) success. To accomplish this, pressure gradients and percent stenoses were compared to stress thallium-201 regional myocardial perfusion before and after 56 uncomplicated PTCAs in 51 patients with single-vessel coronary artery disease. There were 39 men and 12 women; their mean age was 59 +/- 12 years. No patient had evidence of myocardial infarction. A new quantitative method to assess regional myocardial perfusion was used. Patients exercised for 433 +/- 130 seconds before PTCA and for 545 +/- 126 seconds after PTCA (p less than 0.001). Group coronary stenosis and translesional pressure gradient decreased from 77 +/- 11% and 48 +/- 5 mm Hg, respectively, before PTCA, to 25 +/- 11% and 9 +/- 5 mm Hg, respectively, after PTCA (p less than 0.001). Regional myocardial perfusion in the segment of the diseased (dilated) coronary artery increased after PTCA from 77 +/- 17% to 94 +/- 9% (p less than 0.001). Although a significant relationship was noted between regional myocardial perfusion and percent stenosis and translesional pressure gradient, a large individual scatter was present (r values lower than 0.55). We conclude that the final translesional pressure gradient during PTCA is not a better measure of immediate PTCA success than the angiographic percent stenosis.

The effect of radiofrequency-generated thermal energy on the mechanical and histologic characteristics of the arterial wall in vivo: implications for radiofrequency angioplasty

Abrupt reclosure of atherosclerotic vessels after percutaneous transluminal balloon angioplasty has been blamed on traumatic dissections and elastic recoil of the vessel wall. Thermal energy with compression produces fusion of separated arterial wall layers, and heat appears to alter the elastic recoil of the vessel wall. Radiofrequency (RF) thermal energy has been used to perform vascular anastomoses and thermal angioplasty. A simple in vivo experiment was designed to describe and quantitate vascular tissue weld strength produced by a range of RF thermal energy levels. Canine carotid arteries were compressed between a pair of modified bipolar forceps that applied RF energy, causing occlusive tissue welds between the apposed intimal surfaces. The strength of the welds was evaluated by measuring the perfusion pressure required to reopen the vessel lumen. A dosimetry range of 0 to 205 joules showed a typical dose-response curve for the relationship between energy applied and bond strength, plateauing at approximately 300 mm Hg. Light microscopy showed fusion of the inner surfaces of the vessel with preservation of vessel wall architecture. Additionally inflation of a bipolar RF balloon catheter in the normal canine carotid lumen produced an alteration of vessel profile angiographically and histologically. Results of these preliminary experiments suggest that balloon angioplasty with adjunctive RF thermal energy may have benefits in reducing the factors causing acute failure of conventional percutaneous transluminal balloon angioplasty.

Histopathologic examination of material from angioplasty balloon catheters used in vivo in human coronary arteries

Reports on vascular pathology post-PTCA in both human and animal coronary vessels have revealed medial and intimal cracks and tears, thrombus formation, platelet accumulation, and loss of endothelial cells. The extent and type of damage can currently be assessed in vivo at the macro level by means of coronary artery angiography. However, this technique cannot define vessel wall characteristics at the cellular level. Our hypothesis is that vessel wall material may adhere to the balloon and thus provide a source for coronary artery cytological investigation in vivo. Ten balloon catheters were evaluated to discern any material which was dislodged from the coronary artery and which remained attached to the balloon catheter or guide wire. Our results indicate that angioplasty catheter balloons frequently have adherent collagen, endothelial cells, organized thrombus, and plaque with obvious cholesterol clefts, that can be retrieved and examined histologically. We conclude that material is often dislodged from the plaque during PTCA. In addition, plaque material removed by the balloon catheter offers an unusual opportunity to analyze the morphologic characteristics of cells from the human coronary artery in vivo.

Morphologic correlates of coronary angiographic patterns at the site of percutaneous transluminal coronary angioplasty

Over the last 10 years considerable interest has been paid in the angiographic recognition of successful percutaneous transluminal coronary artery angioplasty (PTCA), complication of the technique, and angiographic predictors of restenosis. This report summarizes various angiographic patterns visualized at the site of angioplasty and correlates these patterns with morphologic findings. Of 66 patients undergoing PTCA for chronic or unstable angina pectoris, 76 PTCA sites were available for analysis. The two most common angiographic patterns at the angioplasty site (intimal flap = 43%, intraluminal haziness = 38%) correlated morphologically with intimal-medial splits with localized dissections (79%). Shallow, superficial intimal lesions, laminated thrombus, and adventitial tears accounted for the remaining morphologic changes. Eight PTCA sites without morphologic injury corresponded to smooth wall changes and spasm at angiography.

Balloon angioplasty of aortocoronary saphenous vein bypass grafts: a histopathologic study of six grafts from five patients, with emphasis on restenosis and embolic complications

Among 103 patients undergoing percutaneous transluminal balloon angioplasty of obstructed aortocoronary saphenous vein bypass grafts at the Mayo Clinic, six grafts from 5 patients were available for histopathologic examination. The interval from graft insertion to angioplasty ranged from 5 to 105 months and that from angioplasty to graft excision ranged from 6 h to 24 months. Angioplasty produced intimal fissures in three grafts initially obstructed by intimal fibromuscular proliferation. Healing and restenosis resulted from filling of lacerations with fibrocellular tissue and apparently also from restitution of muscular tone. In two of three grafts initially narrowed by atherosclerosis, balloon angioplasty cause extensive plaque rupture and restenosis resulted from extrusion of plaque debris and secondary luminal thrombosis. In the third graft, angioplasty produced no distinct lesions and late restenosis was due to progressive atherosclerosis of the vein graft. Atheroembolization was observed in both patients with plaque rupture and was associated with reoperation in one and death in the other. In conclusion, the results derived from six saphenous vein bypass grafts subjected to balloon angioplasty indicate that restenosis may result from intimal fibrocellular proliferation, thrombosis, restitution of muscular tone and progressive atherosclerosis. Symptomatic atheroembolization may occur in grafts greater than 1 year old.

Assessment of coronary angioplasty by an automated digital angiographic method

Digital subtraction coronary angiograms (DSA) of 63 patients who had undergone coronary angioplasty (PTCA) for a total of 73 lesions were analyzed with an automated border-detecting computer program capable of simultaneous geometric and densitometric cross-sectional area estimation. The computer measurements were compared with visual interpretation of the 35 mm cineangiograms. The results indicated that visual reports of cineangiograms tend to overestimate the pre-PTCA diameter percent stenosis and to underestimate the post-PTCA residual stenosis in comparison with the computer (p less than 0.001 in bot cases). There was good agreement between geometric and densitometric area percent stenoses calculated by the program on the pre-PTCA digital angiograms (r = 0.82, p less than 0.001, mean of their differences = -0.2 with standard deviation = 6.1). Following PTCA, however, important discrepancies between the two methods existed (r = 0.71, p less than 0.001, mean of their differences = 1.0 with standard deviation = 18.6). Following PTCA (but not pre-PTCA), densitometric evaluation demonstrated a significantly greater mean coefficient of variation between different views (69%) than did the geometric evaluation on the same views (24%). We conclude (1) that visual interpretation of cine coronary angiograms compares poorly with quantitative methods for both the selection of PTCA candidates and the assessment of the results; (2) that the geometric and densitometric characteristics do not agree in describing the degree of post-PTCA residual stenosis; and (3) that after angioplasty, important discrepancies between densitometric evaluation in different views are observed.