The Evaluation of the Safety and Efficacy of Transradial Coronary Procedures

Objectives To evaluate the safety and efficacy of transradial coronary procedures (TRCP). Methods The data of 83 cases who accepted transradial coronary angiography (CAG) and transradial percutaneous coronary intervention (PCI) in our department were summarized. The success rates, proximal coronary complications, peripheral vascular complications, severe vagal reflex, mean operation time (MOT), mean recumbent time (MRT), mean hospital-staying time (MHT) were analyzed. The data were compared with that of 420 cases of transfemoral coronary procedures (TFCP) in the same period. Results Success rates and proximal coronary complications were similar in both groups. Severe vagal reflexes were less in TRCP group than in TFCP group. MOT was longer in TRCP group. MRT and MHT were shorter in TRCP group. 12( 14.5%) radial artery spasm, 3(3.6%) radial artery obstruction, 1 sudden respiratory arrest caused by jugular hematoma were observed in TRCP group. Conclusions The efficacy and safety of TRCP are definite. TRCP is more economical. For the purpose of properly evaluate the peripheral vascular complications of TRCP, it is necessary to pay special attention to radial artery occlusion, radial artery stenosis, and jugular hematoma.     

Left main coronary stenosis as a late complication of percutaneous angioplasty:an old problem, but still a problem

Objective Accelerated left main coronary stenosis (LMCS) is a known potential late complication of coronary artery catheter procedures. The aim of this study was to assess the current occurrence of LMCS as a delayed complication of percutaneous angioplasty (PTCA) of the left coronary branches in our institution. Methods The medical records of patients referred for coronary artery by-pass surgery from the same Cardiology Unit in the January 2003 to December 2006 period and presenting a significant (> 50%) LMCS as a new finding following a PTCA of the left coronary artery branches, were reviewed. Patients with retrospective evidence of any LMCS at previous coronary angiographies preceding the percutaneous procedure were excluded. Results Thirty-seven patients (5 females, mean age 71.1±8.6 years) out of 944 (4%) having undergone a PTCA, fulfilled the inclusion criteria, 19 (51%) after a procedure also involving the LAD coronary artery. Extraback-up guiding catheters were used in most cases. Use of multiple wires or balloons was observed in 3 cases (8%). Rotablator and proximal occlusion device were used in one case respectively (3%). Twenty patients (54%) have had more than one percutaneous coronary intervention on the left coronary branches. The mean time elapsed from the first angioplasty and surgical intervention was 18.1±7.8 months. Conclusions The potential occurrence of LMCS following a percutaneous intervention procedure, especially when complicated and repeated, should not be underestimated in the current era. This evidence may offer the rationale to schedule non-invasive imaging tests to monitor left main coronary patency after the procedure as well as to fuel further research to develop less traumatic materials.     

Impact for incomplete correction of myocardial ischemia on long-term prognosis in patients with revascularization

正Objective To compare the prognosis between complete and incomplete revascularization(RVS)based on myocardial perfusion imaging(MPI)and coronary angiography(CAG)in patients with coronary artery disease(CAD).Methods A total of 202 patients with MPI confirmed myocardial ischemia and receiving RVS within 3months of diagnosis in our hospital from 2007-10 to 2010-12 were retrospectively studied.Based on CAG and MPI     

Computed tomography coronary angiography in patients with acute myocardial infarction without significant coronary stenosis

Background It is known that 9-31% of women and 4-14% of men experiencing an acute myocardial infarction(AMI) have normal coronary arteries or non-significant coronary disease at angiography.Computed tomography coronary angiography(CTCA) can non-invasively identify the presence of coronary plaques even in the absence of significant coronary artery stenosis.This study evaluated the role of 64-slice CTCA in detecting and characterising coronary atherosclerosis in patients with a documented AMI but without significant coronary artery stenosis.Methods and Results Consecutive patients with AMI but without significant coronary stenosis at coronary angiography(CA) underwent late gadolinium-enhanced magnetic resonance(LGE-CMR) and CTCA.Only the 50 patients with an area of MI identified by LGE-CMR were included in the study.All of the coronary segments were assessed for the presence of coronary plaques.CTCA identified 101 plaques against the 41 identified by CA:61(60.4%) located in infarct-related arteries(IRAs) and 40(39.6%) in non-IRAs.In the IRAs,22 plaques were non-calcified,17 mixed,and 22 calcified;in the non-IRAs,five plaques were non-calcified,eight mixed,and 27 calcified(P = 0.005).Mean plaque area was significantly greater in the IRAs than in the non-IRAs(6.1 ± 5.4 mm 2 vs 4.2 ± 2.1 mm 2,P = 0.03);there was no significant difference in mean percentage stenosis(33.5% ± 14.6 vs 31.7% ± 12.2,P = 0.59),but the mean remodelling index was significantly different(1.25 ± 0.41 vs 1.08 ± 0.21,P = 0.01).Conclusions CTCA detects coronary atherosclerotic plaques in segments of non-stenotic coronary arteries that are underestimated by CA,and identifies a different distribution of plaque types in IRAs and non-IRAs.It may therefore be valuable for diagnosing coronary atherosclerosis in AMI patients without any significant coronary stenosis.     

Increased level of glycated hemoglobin portends high risk of coronary artery stenosis

Background Increased level of glycated hemoglobin(HbA1c) is associated with higher incidence of coronary artery disease(CAD) in the diabetics. However, the relationship between HbA1c and the risk of coronary artery stenosis in the non-diabetics is controversial. Methods A retrospective research was conducted on 338 enrolled participants who have undergone 2 times of coronary angiographic examination within the past year. Clinical and laboratory variables at the initial and the second time of admission were collected. According to the initial median HbA1c level, all participants were divided into two groups named lower and higher groups. The relationship between HbA1c level and the risk of coronary artery stenosis over time was evaluated. Results The initial values of HbA1c in lower and upper groups were 5.78 ± 0.35% and 6.21 ± 0.32%(P 0.05). As compared to the lower group, the percentages of male and smoking participants, and the serum level of CRP were significantly higher in the higher group(P 0.05). Other traditional risk factors were comparable between the two groups.There were 54.2% and 55.2% participants with single vessel stenosis, and 45.8% and 44.8% with multiple vessel stenoses, respectively in the two groups without significant difference. The second time of admission, were 308.5± 25.4 days(lower group) and 300.7 ± 30.1 days(higher group) from the initial admission. Although no significant changes of HbA1c level were observed when compared to initial, HbA1c level in the higher group was still significantly higher in comparison to the lower group(6.24 ± 0.39% vs. 5.80 ± 0.36%, P = 0.008). The percentage of new coronary artery stenosis(≥ 50% stenosis) was higher in the higher group than that in the lower group(41.7% vs. 32.3%, P 0.001). Multivariate regression analyses suggested that HbA1c remained independent factor associated with coronary artery stenoses after extensive adjustment for risk factors. Conclusion In the nondiabetics, increased baseline HbA1c level portends the risk of coronary atherosclerotic plaque progression over time.     

Elevated serum levels of MMP-1 are related to atherosclerosis of the vessel proximal to the myocardial bridge

Background Atherosclerosis (AS) of the vessel proximal to the myocardial bridge (MB) is usually found in patients with chest pain undergoing coronary angiography. Matrix metalloprotease-1 (MMP-1) plays an essential role in the initiation and progression of AS. However, its role in AS of the vessel proximal to the MB is unclear. Objective The role of MMP-1 in AS of the vessel proximal to the MB was investigated [VAC1]. Methods We measured MMP-1 serum levels and compared clinical characteristics between two groups. Results MMP-1 serum levels were higher in Group 1 than in Group 2 (25.7 ± 6.1 ng / mL vs 12.6 ± 5.8 ng / mL, P < 0.001); Clinical characteristics had no significant difference between two groups. Conclusion Increased serum levels of MMP-1 might be associated with AS of the vessel proximal to the MB in the mid LAD.     

3T磁共振增强全心冠状动脉成像技术临床应用价值

Objective To investigate the clinical application, feasibility and value of 3 T wholeheart contrast enhanced free-breathing navigator-gated three-dimensional coronary magnetic resonance angiography (CE-CMRA). Methods 3 T CE-CMRA was used to examine patients with suspected coronary heart disease (CAD). Gd-BOPTA(0. 2 mmol/kg) was injected intravenously with slow infusion rate(0. 3ml/s) to perform enhancement. Data were post-processed to obtain principal branches of coronary artery and picture quality was evaluated. According to results of selective coronary arteriography ( SCAG ), the diagnostic accuracy of CE-CMRA for diagnosing CAD was judged by means of detecting significant stenosis ( ＞50% ) of the principal branches based on the 9 segments of coronary artery. Results Twenty-three out of 26 patients successfully completed the examination. The mean scanning time was ( 10. 4 ± 2. 1 ) minutes,178 out of 202 (88. 1% ) SCAG demonstrated segments could be evaluated by CE-CMRA. The imaging quality was superior in proximal and middle segments of coronary artery principal branches than in distal segments. Based on patient-level, there were 9 positive cases and 14 negative cases examined by CE-CMRA compared with 11 positive cases and 12 negative cases examined by SCAG, respectively. The whole diagnose accordance rate of CE-CMRA was 91.3% (21/23)compared with SCAG. The sensitivity, specificity and negative predictive values were 81.8% (9/11), 88.5% (169/191) and 98.8% (9/31)respectively. Conclusions 3 T CE-CMRA is a feasible non-invasive imaging modality for diagnosing CAD,especially to detect significant stenosis in proximal and middle segments of coronary artery principal branches. However, the detecting efficacy is limited in assessing stenosis of distal segment and small branches of coronary artery.     

3T磁共振增强全心冠状动脉成像技术临床应用价值

Objective To investigate the clinical application, feasibility and value of 3 T wholeheart contrast enhanced free-breathing navigator-gated three-dimensional coronary magnetic resonance angiography (CE-CMRA). Methods 3 T CE-CMRA was used to examine patients with suspected coronary heart disease (CAD). Gd-BOPTA(0. 2 mmol/kg) was injected intravenously with slow infusion rate(0. 3ml/s) to perform enhancement. Data were post-processed to obtain principal branches of coronary artery and picture quality was evaluated. According to results of selective coronary arteriography ( SCAG ), the diagnostic accuracy of CE-CMRA for diagnosing CAD was judged by means of detecting significant stenosis ( ＞50% ) of the principal branches based on the 9 segments of coronary artery. Results Twenty-three out of 26 patients successfully completed the examination. The mean scanning time was ( 10. 4 ± 2. 1 ) minutes,178 out of 202 (88. 1% ) SCAG demonstrated segments could be evaluated by CE-CMRA. The imaging quality was superior in proximal and middle segments of coronary artery principal branches than in distal segments. Based on patient-level, there were 9 positive cases and 14 negative cases examined by CE-CMRA compared with 11 positive cases and 12 negative cases examined by SCAG, respectively. The whole diagnose accordance rate of CE-CMRA was 91.3% (21/23)compared with SCAG. The sensitivity, specificity and negative predictive values were 81.8% (9/11), 88.5% (169/191) and 98.8% (9/31)respectively. Conclusions 3 T CE-CMRA is a feasible non-invasive imaging modality for diagnosing CAD,especially to detect significant stenosis in proximal and middle segments of coronary artery principal branches. However, the detecting efficacy is limited in assessing stenosis of distal segment and small branches of coronary artery.     

Efficacy of multiple biliary stenting for refractory benign biliary strictures due to chronic calcifying pancreatitis

AIM To investigate endoscopic therapy efficacy for refractory benign biliary strictures(BBS) with multiple biliary stenting and clarify predictors.METHODS Ten consecutive patients with stones in the pancreatic head and BBS due to chronic pancreatitis who underwent endoscopic therapy were evaluated. Endoscopic insertion of a single stent failed in all patients. We used plastic stents(7F, 8.5F, and 10F) and increased stents at intervals of 2 or 3 mo. Stents were removed approximately 1 year after initial stenting. BBS and common bile duct(CBD) diameter were evaluated using cholangiography. Patients were followed for ≥ 6 mo after therapy, interviewed for cholestasis symptoms, and underwent liver function testing every visit. Patients with complete and incomplete stricture dilations were compared.RESULTS Endoscopic therapy was completed in 8(80%) patients, whereas 2(20%) patients could not continue therapy because of severe acute cholangitis and abdominal abscess, respectively. The mean number of stents was 4.1 ± 1.2. In two(20%) patients, BBS did not improve; thus, a biliary stent was inserted. BBS improved in six(60%) patients. CBD diameter improved more significantly in the complete group than in the incomplete group(6.1 ± 1.8 mm vs 13.7 ± 2.2 mm, respectively, P = 0.010). Stricture length was significantly associated with complete stricture dilation(complete group; 20.5 ± 3.0 mm, incomplete group; 29.0 ± 5.1 mm, P = 0.011). Acute cholangitis did not recur during the mean follow-up period of 20.6 ± 7.3 mo.CONCLUSION Sequential endoscopic insertion of multiple stents is effective for refractory BBS caused by chronic calcifying pancreatitis. BBS length calculation can improve patient selection procedure for therapy.     

Prediction of synchronous colorectal cancers by computed tomography in subjects receiving an incomplete colonoscopy:A single-center study

AIM:To assess the value of computed tomography(CT)for diagnosis of synchronous colorectal cancers(SCRCs)involving incomplete colonoscopy.METHODS:A total of 2123 cases of colorectal cancer(CRC)were reviewed and divided into two groups according to whether a complete or incomplete colonoscopy was performed.CT results and final histological findings were compared to calculate the sensitivity and specificity associated with CT for detection of SCRCs following complete vs incomplete colonoscopy.Factors affecting the CT detection were also analyzed.RESULTS:Three hundred and seventy-four CRC patients underwent incomplete colonoscopy and 1749received complete colonoscopy.Fifty-six cases of SCRCs were identified by CT,and 36 were missed.In the incomplete colonoscopy group,the sensitivity and specificity of CT were 44.8%and 93.6%,respectively.The positive and negative predictive values were 23.6%and 95.0%,respectively.In contrast,the sensitivity and specificity of CT for the complete colonoscopy group were 68.3%and 97.0%,while the positive and negative predictive values were 22.2%and 98.7%,respectively.In both groups,the mean maximum dimension of the concurrent cancers identified in the CT-negative cases was shorter than in the CT-positive cases(incomplete group:P=0.02;complete group:P<0.01)Topographical proximity to synchronous cancers was identified as a risk factor for missed diagnosis(P=0.03).CONCLUSION:CT has limited sensitivity in detecting SCRCs in patients receiving incomplete colonoscopy.Patients with risk factors and negative CT results should be closely examined and monitored.     

冠状动脉造影检查对心肌桥的诊断价值

目的 探讨冠状动脉造影检查对心肌桥诊断的应用,研究心肌桥和冠状动脉粥样硬化的相关性.方法 收集1523例患者冠状动脉造影检查资料,分析心肌桥检出率,观察心肌桥的发生位置、壁冠状动脉收缩期狭窄程度、心肌桥血管合并粥样斑块的位置、斑块处管腔狭窄程度.结果 全部1523例患者中,201例患者检查结果正常,1225例患者检出粥样斑块,231例患者检出心肌桥.心肌桥检出率为15.2％,共检出心肌桥235处.心肌桥位置：右冠状动脉1处,左主干1处,旋支1处,对角支3处,左前降支229处,以左前降支中段多见,壁冠状动脉收缩期轻度狭窄为主.纯心肌桥97例.134例患者心肌桥血管合并粥样斑块144处,斑块位置：心肌桥近端111处,心肌桥段19处,心肌桥远端14处.心肌桥近端血管粥样硬化较心肌桥段、心肌桥远端发生率高,但粥样斑块的形成与壁冠状动脉收缩期的狭窄程度无显著相关（P＞0.05）.结论 心肌桥多见于左前降支中段血管,壁冠状动脉收缩期多为轻度狭窄,血管合并粥样硬化,多见于心肌桥前端,但粥样斑块的形成与壁冠状动脉收缩期狭窄程度无明显相关性.冠状动脉造影检查对心肌桥及心肌桥合并粥样硬化的诊断有重要价值.     

Noninvasive measurement of coronary artery blood flow using combined two-dimensional and Doppler echocardiography

Noninvasive measurement of left anterior descending coronary artery flow was attempted in 20 normal subjects and 80 patients with cardiovascular disease (valvular heart disease in 34, ischemic heart disease in 26, cardiomyopathy in 15 and other diseases in 5) using combined two-dimensional and Doppler echocardiography. A tubular structure about 2 mm in diameter containing Doppler flow signals was identified in the anterior interventricular sulcus in 7 (35%) of the normal subjects and 40 (50%) of the patients with cardiovascular disease. The blood flow within the tubular structure exhibited a biphasic flow pattern, consisting of systolic and diastolic phases with higher velocity during diastole. The highest velocities were observed in early diastole and, in several cases, a small peak was detected during the atrial contraction phase. On the basis of its spatial orientation and characteristic flow pattern, the tubular structure was identified as the midportion of the left anterior descending coronary artery. In a number of cases it was difficult to detect the systolic blood flow. Although blood flow was normally directed from the cardiac base to the apex, it was reversed toward the base in the patients with a bypass graft to the left anterior descending coronary artery. In patients with severe aortic insufficiency, however, flow velocity was lower during diastole than during systole and the duration of diastolic flow was reduced, failing to continue to the end of diastole. Flow velocity was high in patients with a bypass graft to the left anterior descending coronary artery, aortic stenosis or hypertrophic cardiomyopathy.(ABSTRACT TRUNCATED AT 250 WORDS)     

Intravascular ultrasound: potential tool to assess coronary anastomosis quality

Coronary angiography and Doppler flow measurements are most commonly used to assess the patency of anastomoses in the operating theater. Intravascular ultrasound might be another means of monitoring the surgical procedure during coronary artery bypass. Five sheep underwent off-pump bypass of the left anterior descending coronary artery using the left internal mammary artery. The running suture was evaluated by intraoperative fluoroscopy and a coronary intravascular ultrasound probe inserted into the target artery proximal to the anastomosis. Macroscopic examination of the anastomosis was performed to validate the angiographic and intravascular ultrasound images. The diameter, cross-sectional area, and compliance of each anastomosis were calculated in systole and diastole. All anastomoses were patent without signs of stenosis. In one case, intravascular ultrasound showed an intimal flap, which was confirmed by macroscopic examination. The mean major anastomotic diameter was 4.5 +/- 0.5 mm on angiography and 4.0 +/- 0.5 mm on intravascular ultrasound. From the ultrasound data, the mean cross-sectional anastomotic area was calculated as 6.21 +/- 0.1 mm(2) in systole and 5.49 +/- 0.1 mm(2) in diastole, and these data were used to calculate the cross-sectional anastomosis compliance. Coronary intravascular ultrasound can visualize intima-to-intima apposition and provide reliable calculations of anastomosis compliance.     

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.     

Comparison of early systolic and early diastolic regional function during regional ischemia in a chronically instrumented canine model

Depressed left ventricular function during the early part (first third) of both systole and diastole in the resting state have been reported to be sensitive indicators of coronary artery disease in patients with normal global function at rest. To evaluate the possible mechanisms of these findings, 11 dogs were chronically instrumented with segmental function sonomicrometers in the left circumflex and left anterior descending coronary artery distribution, circumflex coronary flow probes and cuff occluders, aortic flow probes and ventricular pressure transducers. Percent segmental function during the first third of systole and diastole was measured in the control state and with graded circumflex artery flow reductions. Significant decreases in early systolic function with ischemia in the circumflex artery distribution were partially offset by compensatory augmented shortening in the left anterior descending artery distribution. With ischemia in the circumflex distribution, there was prolonged contraction into diastole manifested as impaired relaxation. Simultaneously, in the left anterior descending artery distribution, there was minimal compensatory enhanced relaxation. These results suggest that early systolic dysfunction in ischemic segments may be offset by enhanced function in nonischemic segments, rendering minimal, if any, change in global systolic function. Early diastolic dysfunction in ischemic segments exceeds compensatory changes in nonischemic areas by two-to-four-fold. Hence, early diastolic functional indexes may be more sensitive indicators of ischemia at rest than early systolic functional indexes.     

血管内超声诊断冠状动脉临界病变的临床研究

目的：探讨血管内超声（IVUS）诊断左冠脉前降支及左主干冠状动脉临界病变的应用价值。方法：以60例冠状动脉造影（CAG）诊断的冠状动脉临界病变（包括20例左主干病例,前降支近段20例,前降支中段20例）为标准,分析血管内超声（IVUS）检查冠状动脉临界病变的价值。结果：与CAG检查比较,IVUS检查的冠状动脉平均直径狭窄率均显著升高[左主干：（65．31±7．81）％比（75．28±8．89）％,前降支近段：（66．67±8．79）％比（78．89±7．88）％,前降支中段：（71．55±6．83）％比（75．31±7．81）％,P均〈0．01]。CAG和IVUS检查在斑块钙化及斑块破裂的检出率方面无显著差异（P〉0．05）。结论：CAG不同程度地低估了冠状动脉狭窄,尤其是前降支近段,IVUS可对CAG作有效的补充,并且提高不稳定斑块的检出率,弥补了CAG的不足。     

Nonsymptomatic myocardial bridge causing systolic total narrowing of circumflex artery

Myocardial bridge is defined as the narrowing of any coronary artery segment in systole but a normal diameter in diastole. It is most frequently seen on left anterior descending (LAD) artery. Left circumflex artery (LCx) is very rare. A 62 year-old male patient presented with severe, squeezing chest pain. The electrocardiogram showed T wave inversion in V1–V4 and ST depression in DII, DIII, aVF. Coronary angiography showed complicated lesion on after S2 branches of LAD and myocardial bridge causing 100% systolic narrowing of fourth obtus marginal branch of LCx. Bare metal stent was placed to LAD lesions with no residual occlusion. The patient was discharged with beta-blocker therapy. He had no recurrent chest pain during six months of follow-up.     

Intravascular ultrasound imaging of angiographically normal coronary arteries: a prospective study in vivo.

Intravascular ultrasound imaging (IVUS) was performed to elucidate the discrepancy between clinical history and angiographic findings and to measure the diameter and area of the lumen of the normal left coronary artery in 55 patients who presented with chest pain but had normal coronary angiograms. The left coronary artery (LCA) was scanned with a 4.8F, 20 MHz mechanically rotated ultrasound catheter at 413 sites. Atherosclerotic lesions were identified at 72 (17%) sites in 25 patients. The mean (SD) (range) plaque area was 5.55 (3.56) mm2 (2-26 mm2) and it occupied 28.8 (9.6)% (13-70%) of the coronary cross sectional area. Calcification was detected at 24 (33%) atherosclerotic sites in nine patients. The correlation coefficients for the lumen dimensions measured at normal sites by IVUS and by angiography were r = 0.93 (SEE = 0.43) mm for lumen diameter and r = 0.89 (SEE = 4.27) mm2 for lumen area (both p < 0.001). 16 of the 30 patients in whom no atherosclerotic plaques were detected in the LCA lumen by IVUS had no risk factors of coronary artery disease. The cross sectional area of 90 consecutive images of left main coronary artery (LMCA), proximal left anterior descending coronary artery (proximal LAD), and mid LAD was measured in these 16 subjects. The mean (SEM) areas at end diastole were LMCA 17.33 (7.98) mm2; proximal LAD 13.56 (5.85) mm2; mid LAD 9.75 (4.67) mm2. During the cardiac cycle the cross sectional area changed by 10.2 (4.0)% in the LMCA, by 8.3 (4.7)% in the proximal LAD, and by 9.8 (4.0)% in the mid LAD. In 11 patients with plagues the change in cross sectional area in plague segments (5.8(3.1)%) was significantly lower than in the segments from patients without plagues (p < 0.001). Lumen area reached a maximum in early diastole rather than in late diastole. IVUS can imagine atherosclerotic lesions that are angiographically silent; it also provides detailed information about plague characteristics. The variation in coronary cross sectional area during the cardiac cycle should not be ignored during quantitative analysis. Maximum dimensions in normal segments are reached in early diastole. Further studies are needed to clarify the clinical significance of atherosclerosis detected by IVUS in patients presenting with chest pain but normal coronary angiography.     

Clinical and angiographic profile and follow-up of myocardial bridges: a study of 21 cases

Myocardial bridging describes an angiographic entity, which is any degree of systolic narrowing of a coronary artery observed in at least one angiographic projection. Among the cineangiograms of 3200 patients reviewed, there were 21 cases (19 males) of myocardial bridges--incidence of 0.6 percent. Of these, seven had hypertrophic cardiomyopathy, six had atherosclerotic coronary artery disease and remaining eight had no evidence of either. All 21 patients had myocardial bridges in proximal or mid left anterior descending coronary artery. In addition, one case of hypertrophic cardiomyopathy had whole posterior descending coronary artery under a myocardial bridge. Another case of hypertrophic cardiomyopathy had a short normal segment of 5 mm inside a long myocardial bridge of 35 mm (tandem myocardial bridges). The length of the bridges varied from 10 to 35 mm (mean 24.5 +/- 4.5 mm) and diameter stenosis during systole varied from 40-90 percent (mean 70 +/- 8%). Two patients had large saccular coronary aneurysms proximal to the muscle bridge. Four of the eight patients who had neither hypertrophic cardiomyopathy nor coronary artery disease presented with acute anterior wall myocardial infarction and three of them had regional wall motion abnormality of left descending territory. Of the six patients who had coronary artery disease, one had 60 percent left descending artery lesion and two had recanalized segments proximal to the bridge. Five of the above six patients had significant stenosis of other coronary vessels. Four patients were lost to follow-up (mean period 3.4 +/- 2 years). In the coronary artery disease group, one patient underwent coronary artery bypass graft surgery for 3-vessel disease including graft to left descending artery and one developed inferior wall myocardial infarction. The patients in the hypertrophic cardiomyopathy group and "no hypertrophic cardiomyopathy-no coronary artery disease" group were free of events at last follow-up. Long-term prognosis of isolated myocardial bridges appears to be excellent. Degree of systolic narrowing or length of myocardial bridge does not correlate with event rates on follow-up.     

Atypical phasic coronary artery narrowing

Four unusual cases of phasic (occurring only in systole or only in diastole) coronary artery narrowing are reported. In two cases, diastolic compression of the left anterior descending coronary artery was due to tight pericardial adhesions in patients with aortic insufficiency; in the third case, systolic compression of two right ventricular coronary branches was associated with hypertrophic cardiomyopathy and a normotensive right ventricle; and in the fourth case, a large aneurysm of the inferior wall of the left ventricle caused systolic compression of the posterior descending coronary artery, which was epicardial. The diagnostic and pathophysiologic characteristics of each case are discussed.