Angiographic deterioration of the previously dilated coronary segment induced by angioscopic examination

Intravascular imaging tools in the cardiac catheterization laboratory: comprehensive assessment of anatomy and physiology

Intravascular imaging modalities have an imperative role in contemporary cardiovascular research. Currently, there are several invasive imaging modalities available in the cardiac catheterization laboratory and new technologies are under development. In the current review, we aimed to provide an update on the research applications of contemporary intravascular imaging tools in the cardiac catheterization laboratory. For the purpose of this review, we separately discuss imaging tools for assessment of epicardial disease (fractional flow reserve and hyperemic stenosis resistance), microvascular function (coronary flow reserve, hyperemic microvascular resistance, and index of microcirculatory resistance), endothelial function, atherosclerotic plaque and vascular remodeling (intravascular ultrasound, optical coherence tomography, angioscopy, and near-infrared spectroscopy), and finally the emerging modalities (palpography and wall shear stress profiling).

Coronary angioscopy. Clinical applications

Percutaneous coronary angioscopy is an invaluable alternative imaging modality that can not be used routinely in the interventional cardiac catheterization laboratory. The major value of angioscopy lies in its ability to determine safely, quickly, and accurately intraluminal morphologies before and after coronary interventions. The results from angioscopy can then be used to target more specific treatment strategies, given the vast array of interventional treatment strategies available. Percutaneous coronary angioscopy, however, requires meticulous attention for the proper preparation and use of the angioscope to minimize the potential risks associated with the imaging procedure.

Findings of coronary angioscopy in angiographically normal coronary segments of patients with coronary artery disease

Compared with pathologic studies coronary angiography is a relatively insensitive technique to detect early atherosclerosis. Coronary angioscopy is a new technique providing direct information on luminal vessel surface. To determine whether coronary angioscopy may detect the presence of atherosclerotic disease on angiographically normal coronary segments, 52 patients underwent a study with coronary angioscopy before coronary angioplasty. The mean age was 59 +/- 10 years; 46 patients were men and 6 were women. The reason for coronary angioplasty was unstable angina in 36 patients, stable angina in 8 patients, and silent ischemia in 8 patients. In seven patients angiography revealed luminal irregularities on the coronary segment proximal to the culprit lesion, and all these patients also had proximal disease as demonstrated by coronary angioscopy. In the remaining 45 (87%) patients angiography revealed a smooth-vessel contour proximal to the target lesion. On quantitative angiography these "normal" coronary segments measured 2.8 +/- 0.4 mm in luminal diameter. In 30 (67%) of these patients angioscopy revealed proximal disease on the vessel wall, but in 15 (33%) patients the luminal surface of these segments also appeared normal on angioscopy. Disease as detected by angioscopy in angiographically normal segments included yellow plaque in 19 patients, mural thrombus in 5, mixed plaques in 4, and small flaps in 2 patients. In eight patients coronary angioscopy detected that atherosclerotic disease extended proximally from the target lesion, but in the remaining 22 patients the angioscopic findings appeared to be discrete and well separated from the angiographic lesion. All these plaques were relatively small and did not protrude into the coronary lumen.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioscopic findings during coronary angioplasty of coronary occlusions

OBJECTIVES

This study sought to elucidate angioscopic findings in totally occluded vessels before and after intervention.

BACKGROUND

Coronary angioscopy allows direct visualization of the lumen surface of the coronary arteries; however, the utility of coronary angioscopy during coronary angioplasty of vessels with a total occlusion is unknown.

METHODS

Twenty-one consecutive patients (mean [+/- SD] 58 +/- 9 years, range 39 to 77; 3 women, 18 men) undergoing dilation of an occluded vessel were studied with coronary angioscopy. Occlusions were classified as functional in 8 patients (Thrombolysis in Myocardial Infarction [TIMI] flow grade 1) and anatomic in 13 (TIMI flow grade 0). Once the guide wire had crossed the occlusion, coronary angioscopy was attempted before and after angioplasty.

RESULTS

In all patients, coronary angioscopy before dilation visualized protruding material occluding the coronary lumen where the guide wire was wedged. The occlusion consisted of red thrombus in 19 patients (90%) (2 with isolated occlusive thrombus, 17 with thrombus associated with atherosclerotic plaque) and protruding yellow plaque in 2 patients (10%). However, on angiography only 7 occlusions (33%) had data consistent with thrombus (p < 0.01 vs. coronary angioscopy). Successful dilation was obtained in 20 patients. After dilation, coronary angioscopy was repeated in 18 patients, revealing residual thrombus with plaque in 16 (89%) and a residual yellow plaque in 2. In addition, coronary angioscopy revealed coronary dissections in 13 patients (72%); however, angiography revealed dissections only in 10 patients (55%) and residual thrombus in 2 (10%) (p < 0.001). In one patient, coronary angioscopy visualized silent distal embolization of a red thrombus not previously recognized on angiography.

CONCLUSIONS

Before intervention, coronary angioscopy provides unique insights into the pathologic substrate of occluded coronary vessels. An occlusive plaque with thrombus is the most common underlying substrate in these lesions. After successful dilation, angiographically silent mural thrombus is seen in most patients. This information could be used to assist in the selection of candidates and type of coronary interventions and could also prove to be of prognostic value in patients with occluded vessels.