Size of coronary artery in a myocardial bridge compared with adjacent nontunneled left anterior descending coronary artery

Patients with myocardial bridging (MB) may experience myocardial ischemia. Coronary stenting was reported to serve as an effective interventional approach to improve symptoms in selected patients with MB, but is related to high risk of coronary perforation. The aim of this study is to investigate vessel area in the myocardial bridge segment in comparison to that of adjacent segments proximal and distal to MB using intravascular ultrasound. A total of 81 myocardial bridge segments, characterized by a half-moon-shaped echolucent zone surrounding the intramural artery, were found in 78 patients using intravascular ultrasound. The cross-sectional area within the external elastic membrane and minimum and maximum diameters in the myocardial bridge segment and adjacent reference vessel segments were measured. Diastolic cross-sectional area within the external elastic membrane in the myocardial bridge segment was significantly smaller than that in adjacent segments both proximal and distal to MB (5.48+/-2.59 vs 9.40+/-3.48 and 7.22+/-2.87 mm2, respectively, both p<0.001). Maximum vessel diameter in the myocardial bridge segment during diastole was also smaller than that in the segment distal to MB (2.74+/-0.61 vs 3.12+/-0.59 mm, p<0.001). In conclusion, our study showed that vessel area in the myocardial bridge segment was smaller than that in adjacent segments proximal and distal to MB.     

Coronary Artery Shape and Flow Changes Induced by Myocardial Bridging

Changes in coronary shape and blood flow induced by myocardial bridging were analyzed in a 56-year-old patient with symptoms of unstable angina after the exclusion of other heart disease. Coronary angiography demonstrated a 1.8-cm long myocardial bridge in the middle part of the left anterior descending coronary artery. In systole, an eccentric compression of the artery occurred, resulting in a stenosis that occupied 86% of the diameter and 96% of the area. Intraluminal ultrasound was performed with a 20-MHz transducer in a 4.8-Fr catheter sheath (Boston Scientific Corp.) connected to an ultrasound console (Diasonics Inc.). A side saddle catheter was introduced into the left anterior descending coronary artery via a giant guiding catheter. A circular shape with typical systolic pulsation was seen in the proximal part of the artery (maximal and minimal diameters 3.6 mm and 3.5 mm, respectively). Distally an eccentric compression of the coronary artery was visualized, decreasing one diameter from 3.0 to 2.6 mm, whereas the orthogonal diameter remained constant at 3.3 mm. The myocardial bridge compressed 160°–180° of the circumference of the artery, leading to a change from a circular to an elliptical arterial shape. A delayed relaxation of the bridging was demonstrated. Only the proximal part of the vessel in the muscle bridge could be passed. Coronary flow was measured using a Doppler 3-Fr 20-MHz catheter (Millar Instruments Inc.) using a pulse repetition rate of 62.5 kHz. Coronary flow velocity was calculated in the proximal part of the left anterior descending coronary artery before and after intracoronary injection of 10 mg papaverine. Phasic coronary flow velocity increased from 14 to 21 cm/sec and mean flow from 6 to 13.5 cm/sec, yielding an estimated flow reserve of 1.5 and 2.2, respectively (normal > 3.0). Thus, intravascular and Doppler ultrasound are useful techniques for analyzing the effect of myocardial bridging on changes in coronary shape and blood flow. An eccentric compression of the coronary artery was visualized with delayed relaxation. Coronary flow reserve was reduced. Further studies in larger patient populations are necessary to demonstrate whether reduction of coronary flow reserve is, in general, related to delayed relaxation in diastole.     

Determinants of coronary artery compliance in subjects with and without angiographic coronary artery disease

OBJECTIVES: The goal of this study was to determine factors contributing to the biomechanical properties of coronary arteries in people with and without angiographic coronary artery disease (CAD). BACKGROUND: The stiffness of the aorta is known to increase with increasing age and in the presence of CAD. However, little is known about the mechanics of coronary arteries, which may have important clinical consequences. METHODS: Intravascular ultrasound was used to determine the mechanical properties of coronary arteries and plaque behavior in subjects with CAD (n = 38), those with chest pain but angiographically normal coronary arteries (N) (n = 9) and those early (<2 weeks) after cardiac transplant (T) (n = 14). RESULTS: Coronary arteries dilated during systole in all groups, but cross-sectional compliance and distensibility were lowest in the proximal left anterior descending artery (LAD) in the subjects with CAD compared with the N and T groups (compliance: 1.2 +/- 0.2 vs. 1.7 +/- 0.5 and 2.7 +/- 0.6 x 10(-2) mm(2) mm Hg(-1) [mean +/- SEM] respectively, p < 0.02 CAD vs. T; distensibility: 0.8 +/- 0.2 vs. 1.7 +/- 0.5 and 1.7 +/- 0.3 x 10(-3) mm Hg(-1), p < 0.05 CAD vs. T). There was extensive plaque in the CAD group, and plaque was also present in the N group, but minimal atheroma was present in the T group. Plaque cross-sectional area diminished significantly during systole in both the LAD and circumflex arteries. Absolute changes were: 0.50 +/- 0.30, 0.33 +/- 0.11 and 0.68 +/- 0.13 mm(2) in the proximal LAD, distal LAD and proximal circumflex arteries, respectively. In subjects with atheroma, there was a significant correlation between cross-sectional compliance and plaque compression at all sites, and plaque compression was a significant determinant of cross-sectional compliance at both proximal sites in multiple regression analyses with age, mean arterial pressure and extent of plaque as the other independent variables. CONCLUSIONS: A major determinant of the systolic increase in coronary luminal area in patients with atheroma is a reduction in plaque cross-sectional area during systole.     

New signs characteristic of myocardial bridging demonstrated by intracoronary ultrasound and Doppler.

BACKGROUND: Large discrepancies exist concerning the incidence of myocardial bridging. This has been reported to be 0.5%-2.5% following coronary angiography but 15%-85% following autopsy. The purpose of the study was to use intravascular ultrasound and intracoronary Doppler to study the morphology and flow characteristics of myocardial bridging in order to find feasible parameters of this syndrome. METHODS AND RESULTS: Intravascular ultrasound was performed in 62/69 patients in whom typical angiographic 'milking effects' were present. In 48 patients, intracoronary Doppler was performed. A specific, echolucent 'half moon' phenomenon surrounding the myocardial bridge was found in all the patients. The thickness of the half moon area was 0.47 +/- 0.19 mm in diastole and 0.52 +/- 0.23 mm in systole. There was systolic compression of the myocardial bridge with a lumen reduction during systole of 36.4 +/- 8.8%. Using intracoronary Doppler, a characteristic early diastolic 'finger tip' phenomenon was observed in 42 (87%) of the patients. All patients showed no or reduced antegrade systolic flow. Coronary flow velocity reserve was 2.03 +/- 0. 54. After intracoronary nitroglycerin injection, retrograde systolic flow occurred in 37 (77%) of the 48 patients, with a velocity of -22. 2 +/- 13.2 cm. s(-1). Intravascular ultrasound revealed atherosclerotic involvement of the proximal segment in 61 (88%) of the 69 patients, with an area stenosis of 42 +/- 13%. No plaques were found in the bridge or distal segments in the 62 patients in whom it was possible to introduce the ultrasound catheter throughout the bridging segment. CONCLUSION: Myocardial bridging is characterized by the following morphological and functional signs: a specific, echolucent half moon phenomenon over the bridge segment, which exists throughout the cardiac cycle; systolic compression of the bridge segment of the coronary artery; accelerated flow velocity at early diastole (finger-tip phenomenon); no or reduced systolic antegrade flow; decreased diastolic/systolic velocity ratio; retrograde flow in the proximal segment, which is provoked and enhanced by nitroglycerin injection.     

The prevalence and anatomical patterns of intramuscular coronary arteries: a coronary computed tomography angiographic study.

OBJECTIVES: This study sought to report prevalence and radiologic patterns of intramuscular coronary arteries (myocardial bridging) on coronary computed tomographic angiography (CCTA). BACKGROUND: Reported prevalence of intramuscular coronary arteries varies between 5% and 86% in autopsy and 0.8% and 4.9% in coronary angiography. Intramuscular coronary arteries can cause technical problems during coronary bypass surgery, including inadvertent perforation of the right ventricle. METHODS: One hundred and eighteen consecutive patients were studied with CCTA using Brilliance 40/64 multidetector computed tomography (Philips Medical Systems, Cleveland, Ohio). Parameters evaluated were number, length, and depth of intramuscular coronary segments; diameter and evidence of atherosclerosis in the involved artery proximal and within the intramuscular segment; and its course in relation to the interventricular septum and right ventricular wall. RESULTS: Forty-seven intramuscular segments were identified in 36 of 118 (30.5%) patients. Most were located in mid left anterior descending coronary artery (LAD), 27 of 47 (57%), and distal LAD, 7 of 47 (15%). The CCTA features in the LAD showed 3 patterns: superficial septal, 10 of 34 (29.4%); deep septal, 14 of 34 (41.1%); and right ventricular type, 10 of 34 (29.4%). Intramuscular segment length ranged from 13 to 40 mm. Coronary diameter proximal and within the affected segment was 2.2 +/- 0.5 mm versus 1.6 +/- 0.6 mm for the LAD, and 1.9 +/- 0.3 mm versus 1.5 +/- 0.6 mm for the remaining arteries, respectively. Depth ranged from 0.1 to 5.6 mm. CONCLUSIONS: Prevalence of intramuscular coronary arteries on CCTA is in concordance with most pathological reports and higher than in angiographic series. The CCTA clearly showed presence, course, and anatomical features of intramuscular coronary arteries. Coronary computed tomographic angiography may provide potentially useful information in the preoperative evaluation of candidates for coronary bypass surgery.     

Long-term safety of intravascular ultrasound in nontransplant, nonintervened, atherosclerotic coronary arteries

OBJECTIVES: The goal of this study was to demonstrate that intravascular ultrasound (IVUS) examination of native coronary arteries does not result in an acceleration of the atherosclerotic process. BACKGROUND: Intravascular ultrasound is increasingly used to assess the effects of pharmacologic agents on atherosclerosis. METHODS: Intravascular ultrasound examinations of one coronary artery and coronary angiography were performed in 525 patients at baseline. Patients then underwent a follow-up angiogram 18 to 24 months later. All end points were evaluated in IVUS-related and non-IVUS arteries using quantitative coronary analysis. The study end points were the coronary change score (per-patient mean of minimum lumen diameter changes for all lesions measured), occurrence of new coronary lesions, and progression of preexistent lesions at follow-up. Acute angiographic and clinical complications were also analyzed. RESULTS: Coronary change score was -0.06 +/- 0.23 mm and -0.05 +/- 0.21 mm for IVUS-related and non-IVUS arteries, respectively (p = 0.35). The increase in percent diameter stenosis from baseline to follow-up was 0.8 +/- 6.7% and 1.2 +/- 7.0% in the IVUS-related and non-IVUS arteries (p = 0.29). New lesions occurred in 3.6% and 3.9% of IVUS-related and non-IVUS arteries, respectively (p = 0.84). When all coronary lesions were considered, the incidence of lesion progression was not significantly different between IVUS-related (11.6%) and non-IVUS (9.8%) arteries. Coronary spasm occurred in 1.9% of IVUS procedures, and there was one case of acute occlusion with no long-term sequelae. CONCLUSIONS: Intravascular ultrasound does not significantly accelerate atherosclerosis in native coronary arteries and can be used safely to assess progression/regression in clinical trials.     

Intraoperative evaluation of coronary artery bypass graft anastomoses with high-frequency epicardial echocardiography: experimental validation and initial patient studies

There is currently no accepted approach for intraoperative evaluation of the technical adequacy of coronary artery bypass graft anastomoses. High-frequency epicardial echocardiography performed intraoperatively could assess coronary artery bypass graft anastomoses by providing on-line short-axis (cross-sectional) and longitudinal two-dimensional images of the vessels. To validate measurements of anastomoses with high-frequency epicardial echocardiography, luminal diameter determined by high-frequency epicardial echocardiography was compared with that determined histologically after perfusion fixation in 12 dogs studied after coronary artery bypass grafting. Technical errors were deliberately created in some grafts. The results of these animal validation studies showed that maximum luminal diameter of the anastomosis by high-frequency epicardial echocardiography correlated well with histologic measurements (r = .92; high-frequency epicardial echocardiography = 0.8 histology + 0.3). All deliberately created technical errors were detected by an independent observer using high-frequency epicardial echocardiography. After completion of the animal studies, we demonstrated the clinical applicability of this approach in 12 patients. Fifteen coronary artery bypass graft anastomoses were examined intraoperatively with high-frequency epicardial echocardiography. The measured maximum luminal diameter of the anastomosis was greater than the maximum luminal diameter of the native artery, as expected, in all end-to-side anastomoses. However, the maximum luminal diameter of the side-to-side anastomoses was equal to or slightly less than that of the native artery. In this initial patient group, minor technical errors were noted in two of 15 graft anastomoses. In conclusion, high-frequency epicardial echocardiography can accurately measure coronary arterial bypass graft anastomoses and has potential for intraoperative detection of technical errors and inadequacies.     

Percutaneous coronary revascularization using a trilayer metal phosphorylcholine-coated zotarolimus-eluting stent

The ZoMaxx Coronary Stent System elutes the antiproliferative agent zotarolimus via a biocompatible phosphorylcholine polymer loaded onto a novel, thin, stainless steel stent platform containing an 0.0007-inch inner layer of tantalum that enhances fluoroscopic radiopacity. The objective of this single-arm prospective clinical trial was to assess the safety and performance of the ZoMaxx stent for the treatment of coronary artery stenosis. Forty consecutive patients with ischemic coronary occlusive disease due to single de novo obstructive lesions of native coronary arteries were treated with 3 x 18 mm ZoMaxx stents at the Dante Pazzanese de Cardiologie in Sa? Paulo, Brazil, between April and July 2005. Independent core laboratories analyzed quantitative coronary angiography and intravascular ultrasound results immediately after stent implantation, and after 4 months. The lesion, procedure, and device-deployment success rates were all 100% (40 of 40). There were no major adverse cardiac events during the study. Follow-up quantitative coronary angiography at 4 months revealed in-stent and in-segment late lumen losses of 0.20 +/- 0.35 and 0.17 +/- 0.35 mm, respectively. Follow-up intravascular ultrasound at 4 months revealed 6.5 +/- 6.2% neointimal volume obstruction. There were no instances of late acquired stent incomplete apposition or stent thrombosis. In conclusion, the ZoMaxx Coronary Stent can be safely implanted for the treatment of de novo coronary artery stenosis. The inhibition of neointima formation as measured by follow-up angiography and IVUS after 4 months suggests therapeutic potential for the reduction of restenosis.     

Intravascular ultrasound imaging of saphenous vein grafts in vitro: comparison with histologic and quantitative angiographic findings.

The ubiquity of coronary artery disease and the resultant widespread use of saphenous veins for coronary artery bypass surgery has stimulated considerable interest in the morphologic and pathophysiologic alterations these vessels undergo after implantation. This study was undertaken to determine the ability of intravascular ultrasound to identify and characterize abnormalities in saphenous vein grafts. Ten saphenous vein grafts excised at autopsy and nine saphenous vein segments harvested during coronary artery bypass surgery were examined with intravascular ultrasound imaging, quantitative coronary angiographic techniques and histologic analysis. Intravascular ultrasound lumen measurements were strongly correlated with quantitative coronary arteriographic measurements (r 0.91, SEE 0.5 mm). Wall thickness was significantly greater in the vein grafts after long-term implantation than in the freshly harvested veins (average thickness 1.4 +/- 0.5 vs. 0.7 +/- 0.2 mm, p less than 0.007); this finding correlated histologically with vein wall fibrosis. There was good correlation between ultrasound imaging and histologic analysis, with the ability to distinguish among normal intima, intimal hyperplasia, vein wall fibrosis and atheromatous plaque. Thus, this preliminary study demonstrates the ability of intravascular ultrasound to provide real-time cross-sectional images of saphenous veins and morphologic characterization of their walls. This modality may have important clinical applications, including the ability to detect serial changes in vein graft intimal hyperplasia and atherosclerosis.     

Intravascular ultrasound to assess aortocoronary venous bypass grafts in vivo.

In 20 consecutive patients (18 men and 2 women, aged 42 to 72 years) undergoing repeat coronary angiography because of new onset of angina pectoris 4 months to 11 years (mean 53 months) after aortocoronary saphenous venous bypass operation, the graft to the left anterior descending (n = 12), left circumflex (n = 4) or right coronary (n = 2) artery, or a diagonal branch (n = 2) was studied by both intravascular ultrasound and angiography. Sonographic images were obtained using a 4.8Fr catheter with a crystal mechanically rotated at 900 rpm; quantitative coronary angiograms were recorded in biplane projections. In 18 patients, qualitatively as well as quantitatively evaluable images could be recorded; no complications occurred. The venous wall in general appeared to be homogenous; there were no separate layers identifiable. Simultaneous ultrasound and angiographic measurements were performed at a total of 75 sites (2 to 6 per bypass). In 4 of these patients (10 of 75 sites), neither intravascular ultrasound nor angiography revealed any pathologic changes; these bypasses were classified as normal. At the remaining 65 sites, arteriosclerotic lesions were detected in each case by ultrasound, but at only 33 sites by angiography. Median wall thickness was 0.59 mm (95% confidence interval 0.54 to 0.63) in normal grafts and 1.02 mm (0.99 to 1.07; p less than 0.001) in diseased grafts. The cross-sectional luminal area determined by ultrasound correlated well with the angiographic assessment (r = 0.90; p less than 0.001), but the measured values were significantly higher (17 +/- 4 vs 14 +/- 4 mm2; p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

The contrast media iohexol causes vasoconstriction of the proximal left anterior descending coronary artery: implications for appropriate stent sizing

The effect of the contrast agent iohexol on reference vessel size in patients with proximal left anterior descending disease is unknown. Quantitative coronary angiography and intravascular ultrasound were performed in 15 patients with atherosclerotic disease of the proximal left anterior descending. Mean proximal reference vessel diameter was 2.95 +/- 0.59 mm with quantitative coronary angiography and 4.65 +/- 0.66 mm with intravascular ultrasound (P < .05). Intracoronary injection of iohexol resulted in a significant decrease in intravascular ultrasound-measured proximal reference vessel diameter from 4.65 +/- 0.66 mm to 4.47 +/- 0.68 mm (P = .002). Vasoconstrictive response to iohexol in the proximal reference vessel ranged from -0.04 mm to 0.5 mm with a mean of 0.18 +/- 0.16 mm. This study shows that iohexol can cause significant vasoconstriction of the proximal reference vessel in patients with severe disease involving the proximal left anterior descending.     

Vascular anastomosis by argon laser beam

Twenty-four mongrel dogs, weighing 13 to 24 kg, were used to study the effectiveness of anastomosis by Argon Laser beam. After anesthesia, intubation and controlled ventilation, they were submitted to three types of vascular anastomoses: saphenous vein intercarotid artery bypass; left mammary artery/left anterior descending coronary artery bypass; and veno-venous anastomosis. In all groups, 0.8 to 1.5 watts of Argon Laser power were applied for a total time of 90 to 300 seconds. The lower power was for veno-venous anastomoses and the greater was applied for arterial anastomoses. The mean values of resistance of the laser anastomosis to pressure-induced repture were 730 mm Hg in the immediate postoperative study, but increased to 2,500 mm Hg 30 days after surgery. No signs of occlusion were demonstrated at the anastomotic sites by the angiographic and anatomopathological studies performed.     

Intravascular ultrasound for angiographically indeterminant left main coronary artery disease

The precise diagnosis of the presence of significant left main coronary artery disease has profound prognostic and therapeutic implications. Coronary cineangiography has shown to be imprecise and inaccurate to determine the percent stenosis of the left main coronary artery. We report a case with significant left main coronary artery disease in whom coronary cineangiography was in discordance with the clinical data and intravascular ultrasonography. Based on the intravascular ultrasound findings, the patient underwent coronary artery bypass graft surgery. Therefore, the intravascular ultrasonography may be the procedure of choice for assessing indeterminant left main coronary artery lesions by coronary angiography.     

Relation of Basal coronary nitric oxide activity to the burden of atherosclerosis

Coronary disease or its risk factors has been reported to attenuate basal nitric oxide (NO) activity. Intravascular ultrasound was used in the present study to better understand this relation. Basal and stimulated NO activities were assessed in 53 stable subjects. Coronary diameter and velocity (0.014-inch Doppler wire) were measured at baseline and after intracoronary infusion of the NO synthase inhibitor N(G)-monomethyl-l-arginine, acetylcholine (10(-6) M), nitroglycerin (200 microg), and adenosine (24 microg). Intimal thickening was quantified with intravascular ultrasound. N(G)-monomethyl-l-arginine resulted in significant decreases in coronary blood flow (-14 +/- 48%), proximal coronary diameter (-10 +/- 18%), and distal coronary diameter (-10 +/- 9%, all p values <0.0001). Basal NO activity was unrelated to the presence of coronary disease as assessed by angiography and the burden of atherosclerosis as assessed by intravascular ultrasound. Conversely, stimulated NO activity correlated inversely with burden of coronary atherosclerosis (p <0.05). Basal NO activity is relatively preserved in patients who have moderate coronary disease and is not related to the degree of atherosclerosis as assessed by intravascular ultrasound. This is in contradistinction to the impairment of stimulated NO activity in the coronary circulation that characterizes atherosclerosis.     

Coronary vasodilation by noninvasive transcutaneous ultrasound: an in vivo canine study

OBJECTIVES: We evaluated the coronary vasodilatory effects of transcutaneous low-frequency (27-kHz) ultrasound (USD). BACKGROUND: Ultrasound has been shown to affect vascular function. METHODS: Ultrasound energy was administered transcutaneously to 12 dogs. Coronary arterial dimensions were assessed using intravascular coronary ultrasound (IVUS) and quantitative coronary angiography (QCA). RESULTS: The IVUS mid-left anterior descending (LAD) luminal area was 6.77 +/- 1.27 mm(2) at baseline. After 30 s of ultrasound, this area increased by 9% (7.40 +/- 1.44 mm(2), p < 0.05), after 3 min by 19% (8.05 +/- 1.72 mm(2), p < 0.05) and after 5 min increased by 21% (8.16 +/- 1.29 mm(2), p < 0.05). The mean coronary diameter (2.69 +/- 0.33 mm) at baseline (QCA of three segments of LAD and three segments of left circumflex coronary artery) increased by 19.3% (3.21 +/- 0.28 mm) after 5 min of USD exposure. After a 90-min observation period there was a return to baseline values (p = NS). Intracoronary nitroglycerin (NTG) administered to five dogs revealed a similar magnitude of vasodilation as USD. CONCLUSIONS: Noninvasive, transthoracic low-frequency USD energy results in coronary artery vasodilation within seconds of exposure. The vasodilation is reversible and is similar in magnitude to that induced by NTG. Further evaluation is needed to assess its potential applications in humans.     

Preliminary clinical experience with the Heartflo anastomosis device

A clinical, prospective trial to evaluate a multi-suture anastomotic device (Heartflo) is currently underway. This new surgical tool can be used during CABG to perform end-to-side or side-to-side coronary arteries anastomoses with interrupted suture technique. This reports our interim preliminary clinical experience. METHODS: From February to November 2000, we attempted 15 anastomoses with the multi-suture anastomotic device (Heartflo) in 11 patients with coronary artery disease. RESULTS: 7 males, 4 females, mean age 64 +/- 3 yrs received 15 anastomoses with the device. The target vessels were: 8 RCA, 3 LAD, 4 OM. Mean coronary diameter was 2 +/- 0.3 mm. Grafts used were 14 saphenous veins and 1 IMA. 13/15 anastomoses were completed with the device. 5/13 required 0 - 1 additional stitches versus 8/13 requiring more due to inappropriate tissue capture on the native coronary side. Average time was 17.7 +/- 2 min. In 2/15 cases, the procedure was converted to a traditional handsaw anastomosis. Postoperative CK movement without Q-wave in the EKG was observed in 1/11 patients. CONCLUSIONS: This device is a reliable instrument that provides reproducible coronary anastomoses with interrupted suture technique, although it also requires additional measures to improve tissue capture and process of handling sutures before extensive clinical application.     

Long-term effect of perindopril on coronary atherosclerosis progression (from the perindopril's prospective effect on coronary atherosclerosis by angiography and intravascular ultrasound evaluation [PERSPECTIVE] study)

The multicenter EUROPA trial of 12,218 patients showed that perindopril decreased adverse clinical events in patients with established coronary heart disease. The PERSPECTIVE study, a substudy of the EUROPA trial, evaluated the effect of perindopril on coronary plaque progression as assessed by quantitative coronary angiography and intravascular ultrasound (IVUS). In total 244 patients (mean age 57 years, 81% men) were included. Evaluable paired quantitative coronary angiograms were obtained from 96 patients randomized to perindopril and from 98 patients to placebo. Concomitant treatment at baseline consisted of aspirin (90%), lipid-lowering agents (70%), and beta blockers (60%). The primary and secondary end point was the difference of minimum and mean lumen diameters (quantitative coronary angiography) or mean plaque cross-sectional area (IVUS) measured at baseline and 3-year follow-up between the perindopril and placebo groups. After a median follow-up of 3.0 years (range 1.9 to 4.1), no differences in change in quantitative coronary angiographic or IVUS measurements were detected between the perindopril and placebo groups (minimum and mean luminal diameters -0.07 +/- 0.4 vs -0.02 +/- 0.4 mm, p = 0.34; mean luminal diameter -0.05 +/- 0.2 vs -0.05 +/- 0.3 mm, p = 0.89; mean plaque cross-sectional area -0.18 +/- 1.2 vs -0.02 +/- 1.2 mm(2), p = 0.48). In conclusion, we found no progression in coronary artery disease by quantitative coronary angiography and IVUS with long-term administration of perindopril or placebo, possibly because most patients were on concomitant treatment with a statin.     

Nitroglycerin-induced coronary vasodilation in cardiac transplant recipients. Evaluation with in vivo intracoronary ultrasound.

BACKGROUND. Coronary artery vasomotion is altered after cardiac transplantation. The impact of accelerated transplant coronary atherosclerosis and myocardial rejection on vasomotion is not well understood. Intravascular ultrasound is a new imaging method with the ability to study real-time changes in coronary artery dimensions. METHODS AND RESULTS. Epicardial coronary artery response to nitroglycerin was studied in 32 cardiac transplant recipients (age, 47 +/- 11 years) 3 weeks to 10 years after transplantation with intracoronary ultrasound. Cross-sectional luminal area and diameter were measured at a fixed position in the left anterior descending artery immediately before and every 30 seconds for 5 minutes after 0.4 mg of sublingual nitroglycerin. Cross-sectional area increased from a baseline of 13.1 +/- 3.9 mm2 to 15.8 +/- 3.9 mm2 at maximal vasodilation; luminal diameter increased from 4.0 +/- 0.6 mm to 4.5 +/- 0.6 mm. This increase reached statistical significance (p less than 0.001) at 1.5 minutes after administration of nitroglycerin; mean maximum increase occurred at 4.5 minutes (24% for cross-sectional area and 11% for luminal diameter). Patients with biopsy-proven mild or moderate concurrent rejection had a significantly blunted vasodilatory response versus the nonrejection group (9% versus 27% for cross-sectional area, p less than 0.04), although a vasodilatory effect was still present. Nitroglycerin response was well preserved in patients up to 10 years after transplantation; however, there was a trend toward a decreased response in patients studied immediately after transplantation (21% versus 29%, p = 0.37). Coronary intimal thickness, as measured by ultrasound, had no impact on the vasodilatory response (R = 0.23, p = 0.34). CONCLUSIONS. Vasodilatory response to nitroglycerin in cardiac transplant recipients is attenuated during episodes of cardiac rejection. This response is preserved in long-term survivors and is independent of the degree of intimal thickening. Intravascular ultrasound provides a new method to document real-time epicardial coronary vasomotion.     

A reappraisal of the factors affecting early patency of aortocoronary saphenous vein bypass grafts. Current experience with extensive revascularization employing sequential grafting techniques

A number of factors potentially influencing the patency rates of aortocoronary bypass grafts were investigated in a consecutive series of 50 patients by control angiography at 28 +/- 26 days and by univariate and multivariate analysis of a selected set of clinical, surgical and angiographic predictors. There were 234 anastomoses in this series, a mean of 4.7 per patient (range 1 to 9), 215 of which were connected to sequential vein grafts. After surgery, 40 patients were treated with anticoagulants and/or platelet inhibitors. Of the 234 coronary anastomoses studied, 219 were patent (93.6%). Coronary artery diameter, patient's age and previous myocardial infarction were shown to be independent predictors of increased risk of anastomotic occlusion. Arteries less than 1.5 mm in diameter had a patency rate of 84.9%, versus 96.1% for vessels 1.5 mm or larger (p = 0.009). The use of side-to-side anastomoses with sequential grafts seemed to counterbalance the unfavourable effect of small arterial size. Patients aged 65 or older had a lower probability of having all their grafts patent than younger patients did (50 vs 89%, p = 0.01). Patients with previous myocardial infarction similarly had a lower probability of having all their grafts patent compared to patients without previous infarction (68 vs 95%, p less than 0.05); this correlation was explained by a more frequent occlusion rate of grafts directed to fibrotic left ventricular areas. The effect of anticoagulants and of platelet-inhibitors was favourable, but did not reach statistical significance.(ABSTRACT TRUNCATED AT 250 WORDS)     

Volumetric intravascular ultrasound imaging to illustrate the extent of coronary plaque burden in type 2 diabetic patients

BACKGROUND: Although angiography is the gold standard for coronary imaging, its efficacy in outlining diffuse coronary atherosclerosis in diabetic patients remains questionable. We aimed to compare quantitative cineangiographic analysis (QCA) with three-dimensional intravascular ultrasound (IVUS) imaging in type 2 diabetic patients with coronary artery disease. METHODS: IVUS runs of 104 significant coronary lesions in 88 diabetic patients were performed. Arterial remodeling index was calculated as vessel area at minimal lumen area divided by mean reference vessel area. RESULTS: No difference between the two analysis modes was shown for lesion length and minimal lumen diameter, whereas a significant discrepancy between QCA and IVUS was found for diameter stenosis (10 +/- 9% vs. 41 +/- 8%; P<.001) and vessel diameter (3.01 +/- 0.66 vs. 4.53 +/- 0.70 mm; P<.001). A significant difference on arterial remodeling at lesion site was found between insulin-treated diabetic patients and non-insulin-treated diabetic patients (remodeling index: 0.98 +/- 0.16 vs. 1.07 +/- 0.21; P=.04). CONCLUSIONS: Coronary angiographic diagnosis in diabetic patients may be distorted due to a large plaque burden over longer vessel segments and the resulting absence of plaque-free reference segments. This distortion was found to be more pronounced in QCA analysis requiring a reference diameter, whereas volumetric IVUS imaging illustrated coronary artery dimensions more accurately according to anatomic structures. Constrictive arterial remodeling was observed more frequently in type 2 diabetic patients treated with insulin.