Angioscopic differences of coronary intima between diffuse and focal coronary vasospasm: Comparison of optical coherence tomography findings.

BACKGROUND: Coronary artery vasospasm (CS) can be identified as either a diffuse type or focal type; however, the difference in endothelial characteristics between these spasm types remains unclear. The features of coronary intima associated with diffuse spasm and focal spasm using coronary angioscopy (CAS) were evaluated and the optical coherence tomography (OCT) findings were compared. METHODS: CAS and/or OCT observational analysis was performed in 55 patients (mean age: 61.4 years, 31 men) who had acetylcholine-provoked CS (diffuse CS, 31 patients; focal CS, 24 patients). The yellowness of the intima, presence of thrombus in CAS, and intimal characteristics based on the OCT results were evaluated. RESULTS: CAS showed more atherosclerotic yellow plaques at the focal spasm segment than at the diffuse spasm segment (p=0.032). Moreover, there were more thrombi at the focal spasm segment (p=0.039). In addition, OCT results revealed that the intima area, maximum intima thickness, and lipid content in the focal CS group were larger than the diffuse CS group (4.22±1.67mm2 vs. 3.45±2.36mm2; 0.71±0.29mm vs. 0.53±0.30mm; 55.9% vs. 32.0%, p<0.001, respectively). CONCLUSIONS: These results indicate that the presence of atherosclerotic plaques at the spasm site is likely to be related to the occurrence of a focal vasospasm. This may support the difference of features between focal CS and diffuse CS and contribute to precise treatment for each spasm type.

MRI endoscopy using intrinsically localized probes.

Magnetic resonance imaging (MRI) is traditionally performed with fixed externally applied gradient magnetic fields and is hence intrinsically locked to the laboratory frame of reference (FoR). Here a method for high-resolution MRI that employs active, catheter-based, tiny internal probes that utilize the spatial properties of the probe itself for localization is proposed and demonstrated at 3 T. Because these properties are intrinsic to the probe, they move with it, transforming MRI from the laboratory FoR to the FoR of the device itself, analogous to an endoscope. The "MRI endoscope" can utilize loop coils and loopless antennas with modified sensitivity, in combination with adiabatic excitation by the device itself, to restrict the MRI sensitivity to a disk-shaped plane a few mm thick. Excitation with the MRI endoscope limits the eddy currents induced in the sample to an excited volume whose size is orders of magnitude below that excited by a conventional body MRI coil. Heat testing shows maximum local temperature increases of <1 degrees C during MRI, within regulatory guidelines. The method is demonstrated in a kiwifruit, in intact porcine and rabbit aortas, and in an atherosclerotic human iliac artery specimen, with in-plane resolution as small as 80 microm and 1.5-5 mm slice thickness.

Endografting increases total volume of AAA repairs but not at the expense of open surgery: experience in more than 1000 patients.

PURPOSE: To compare the volume of open graft replacements (OGR) for abdominal aortic aneurysm (AAA) versus endovascular aneurysm repairs (EVAR) over time and after modifying selection criteria. METHODS: A review was conducted of 1021 consecutive patients who underwent AAA repair from 1989 through 2002: 496 elective OGRs for infrarenal AAAs (STANDARD), 289 elective EVARs for infrarenal AAAs, 59 complex OGRs for suprarenal AAAs, and 177 emergent OGRs for ruptured AAAs. Patients from 1995 to 2002 were divided into 2 groups based on shifting treatment strategies; 454 patients were treated by STANDARD or EVAR at the surgeon's discretion between 1995 and 2000 (post EVAR). The second group comprised 161 patients treated in 2001-2002 after the introduction of "high-risk" screening criteria (age > or = 72 years, diabetes mellitus, renal dysfunction, impaired pulmonary function, or ASA class IV) that dictated EVAR whenever anatomically feasible. For comparison, 170 STANDARD repairs performed in the 6 years prior to EVAR served as a control. RESULTS: While surgery for ruptured AAAs remained fairly stable over the 14-year period, the number of patients undergoing elective repair increased due to the implementation of EVAR. During the 6 years after its introduction, EVAR averaged 34.3 patients per year; after 2001, the annual frequency of EVAR increased to 41.5 (p > 0.05). In like fashion, the rate of STANDARD repairs increased to 41.3 patients per year versus 28.3 before EVAR (p = 0.032). ASA class IV patients increased by almost 9 fold in the recent period versus pre EVAR (p = 0.006). The overall mortality after elective infrarenal AAA repair decreased between the pre and post EVAR periods (6.5% versus 3.7%, p > 0.05) and fell still further to 1.2% in the most recent period (p = 0.021 versus pre EVAR). CONCLUSIONS: The implementation of an EVAR program increases the total volume of AAA repairs but does not reduce open surgical procedures. By allocating patients to EVAR or open repair based their risk factors, mortality was markedly reduced.

The 'Ermenonville' classification of observations at coronary angioscopy--evaluation of intra- and inter-observer agreement. European Working Group on Coronary Angioscopy.

A European coronary angioscopy working group has been established to create and evaluate a classification system for angioscopic observation. The 'Ermenonville' classification features items, graded in 3-5 categories, such as lumen diameter, shape of narrowing, colours of surface, atheroma, dissection, thrombus, etc. Inter- and intra-observer agreement on the interpretation of angioscopic images, using this classification system, was studied within the working group. Kappa values for chance-corrected intra-observer agreement of the diagnostic items were 0.51-0.67. The mean kappa values for inter-observer agreement were very low at 0.13-0.29. The important items, such as red thrombus and dissection were studied after recoding as either present or absent. These items proved to have a good intra-observer agreement, and an acceptable inter-observer agreement after recoding. Other angioscopic diagnoses should be made with caution. Multicentre angioscopy studies should make use of an angioscopy core laboratory. A set of definitions for coronary angioscopy is proposed, and this working group will re-evaluate observer agreements using these definitions.

Randomized prospective study of angioscopically assisted in situ saphenous vein grafting.

PURPOSE: A study was conducted to test the hypothesis that angioscopically assisted valve lysis and vein branch identification during in situ saphenous vein bypass would reduce technical causes of graft failure, local operative morbidity, and hospital stay. METHODS: Patients requiring primary bypass to an infrageniculate artery were randomly assigned to undergo in situ saphenous vein bypass with valvulotomy and branch identification either under angioscopic visualization with use of short intermittent incisions (scope) or under direct vision with use of a continuous incision (no scope). Data on operative details, morbidity, hospital length of stay, and graft patency were collected prospectively and compared. RESULTS: Fifty-nine patients were enrolled (32 scope, 27 no scope). There were no significant differences between study groups in the incidence of diabetes, claudication versus critical ischemia indications for surgery, or popliteal versus infrapopliteal location of distal anastomoses. Rates of wound complications (9.3% and 3.7%), early graft occlusion (6.2% and 7.4%), and mean postoperative hospital stay (8.0 and 8.6 days) were statistically similar for the scope and no scope groups, respectively. Differences in cumulative secondary patency rates at 48 months (79% scope, 91% no scope) were also insignificant. CONCLUSIONS: Use of angioscopy to assist with preparation of the in situ vein for infrageniculate grafting appears to have no impact on local operative morbidity, hospital length of stay, or midterm graft patency.

Angioscopy after laser and balloon coronary angioplasty.

OBJECTIVES: Percutaneous intracoronary angioscopy was used to study the morphologic changes occurring in coronary arteries after balloon or laser angioplasty. BACKGROUND: Angioscopy is thought to provide details of the coronary vessel lumen and the inner wall. METHODS: Coronary lesions were studied in 44 patients with a 4.5F Imagecath angioscope before and after each interventional procedure. Balloon and laser angioplasty were performed in 21 (group I) and 23 patients (group II), respectively. There was no difference in age, gender or angiographic lesion appearance before the procedure between the two groups. RESULTS: Circumferential visualization of the target lesion was successfully completed in 17 group I and 19 group II patients. A larger lumen than that observed at baseline was seen in all 17 group I and in 13 of the 19 group II patients. Tissue remnants were observed in all group I and II patients. Laser irradiation resulted in characteristic sharp-edged craters. Dissection was identified in 2 of 19 patients before versus 9 of 19 patients after balloon angioplasty (p < 0.05) and in 0 of 23 patients before versus 4 of 23 patients after laser angioplasty (p = NS). Subintimal hemorrhage was observed in 3 of 19 patients before versus 11 of 19 patients after balloon angioplasty (p < 0.05) and in 2 of 23 patients before versus 4 of 23 patients after laser angioplasty (p = NS). The frequency of hemorrhage was higher in group I than in group II (11 of 19 vs. 4 of 23, respectively, p < 0.02). CONCLUSIONS: Angioscopy provides valuable information on lesion morphology after coronary interventions. Balloon dilation results in a high rate of dissection and subintimal hemorrhage. Laser angioplasty is able to ablate obstructing tissue and results in a lower rate of subintimal hemorrhage than balloon dilation.

Comparison of angioscopy and angiography for monitoring infrainguinal bypass vein grafts: results of a prospective randomized trial.

PURPOSE: This study was designed to determine whether, in primary infrainguinal bypass grafts in which only saphenous vein is used as the graft conduit, routine monitoring with intraoperative angioscopy can improve early graft patency as compared with standard monitoring with intraoperative completion angiography; and to delineate the advantages and disadvantages of these two modalities and their respective roles for the routine monitoring of the infrainguinal bypass graft. METHODS: A total of 293 patients undergoing primary saphenous vein infrainguinal bypass grafting were prospectively randomized and monitored with either completion angioscopy or completion angiography. Clinical parameters, indications for operation, graft anatomy, and configuration were evenly matched in both groups. Forty-three bypasses were excluded from the study after randomization, including 12 veins randomized to angiogram, deemed inferior, and prepared with angioscopy. RESULTS: In the 250 bypass grafts (angioscopy 128, angiography 122) there were 39 interventions (conduit, 29; anastomosis, 8; distal artery, 2), 32 with angioscopy and 7 with angiography (p < 0.0001). Twelve (4.8%) of the 250 grafts failed in less than 30 days, four (3.1%) of 128 in the angioscopy group and eight (6.6%) of 122 in the angiography group (p = 0.11 by one-sided hypothesis test). CONCLUSION: Although no statistical improvement in the proportions of failures in primary saphenous vein bypass grafts routinely monitored with completion angioscopy rather than the standard completion angiogram was demonstrated, the study delineates a trend that favors completion angioscopy for routine vein graft monitoring and demonstrates the advantages of angioscopy in preparing the optimal vein conduit.

Angioscopy, coronary thrombi and acute coronary syndromes.

Coronary angioscopy is a new diagnostic imaging technique in which optic fibres are used to directly observe the intracoronary lumen. Angioscopy provides a full colour, high resolution, three-dimensional image of the intracoronary artery surface morphology. Studies using angioscopy revealed that the frequency of coronary thrombi in patients with acute coronary syndromes was higher than previous studies, based on arteriography, had reported. Arteriographic recognition of thrombus in unstable angina was from 1.3% to 52%. On the other hand, thrombi were observed in 88% by angioscopy in patients with rest angina in our study. Whereas ordinary arteriography provides only two-dimensional black and white images, angioscopy can distinguish between a thrombus and a plaque, even if the clot is very small. In a study of 17 unstable angina and 22 myocardial infarction patients, the frequencies of coronary thrombi in the two groups were essentially the same. Grayish-white thrombi were observed in most of the unstable angina patients but in none of the infarction patients. On the other hand, red or mixed red and white thrombi were observed in all infarction patients but in only a few unstable angina patients. This difference may account for the contrasting results of thrombolytic therapy.