Interventricular septal motion in patients with proximal and distal left anterior descending coronary artery lesions

In order to evaluate the ability of the echocardiogram to detect and localize left main or left anterior descending (LAD) coronary artery lesions, 43 patients were studied. The systolic excursion of the left side of the septum and the ratio of posterior wall to septal excursion were measured. Seventeen patients had no LAD lesions; all had systolic septal excursion of 3 mm or greater. Twelve patients with septal excursion of 2 mm or less all had left main or LAD lesions, but 14 other patients with LAD lesions had septal excursions of 3 mm or greater. Nine of 16 patients with LAD lesions proximal to the first septal branch had reduced or absent septal excursion, as did three of ten with LAD lesions distal to the first septal branch. In a setting of coronary artery disease reduced or absent septal motion on echocardiography suggests involvement of the left main or left anterior descending coronary. However, the technique is relatively insensitive, with 54% of the LAD patients having normal septal motion.     

Extensive endarterectomy of the left anterior descending coronary artery combined with coronary artery bypass grafting

BACKGROUND: Complete revascularization of a diffusely diseased left anterior descending (LAD) coronary artery can be accomplished by extensive endarterectomy in conjunction with coronary artery bypass grafting (CABG). The present study was designed to assess the safety of the procedure, and which techniques lead to the best short- and long-term results. METHODS: Between January 1990 and October 1994 106 patients underwent extensive open endarterectomy of the LAD coronary artery combined with CABG at our institution. This group constituted 4.9% of all patients undergoing CABG during this period. The mean age of those studied was 64.4 +/- 9.2 years and 92% were male. In 22 patients (21%) the procedure was a repeat CABG and 12% had had percutaneous transluminal coronary angioplasty prior to the operation. Ninety-one per cent of the patients were in Canadian Cardiovascular Society (CCS) angina class 3 or 4, 91% had three-vessel disease and 36% had unstable angina at the time of surgery. The mean preoperative left ventricular ejection fraction was 53.6 +/- 14.9% (range, 15-80%). The internal mammary artery (IMA) was used to bypass the LAD coronary artery in 40 patients (38%) and a saphenous vein graft (SVG) was used in 66 patients. In 25 of the IMA bypass group an additional venous patch was used (IMA+P). RESULTS: The overall mortality rate was 9.4% (10 patients), including seven immediate postoperative deaths. When the IMA was used as a conduit the mortality rate was only 5.0%. There were seven (6.6%) postoperative non-fatal myocardial infarctions. There was a low incidence of other postoperative complications, similar to that following CABG without endarterectomy performed during the same period. Multivariate analysis identified emergency operation, two-vessel endarterectomy and female sex as independent risk factors for mortality. Upon follow-up study of 94 hospital survivors (98%), at a mean of 26.5 months (range, 1-48 months), all endarterectomy patients were in CCS class 1 or 2. Seventy-eight patients (83%) had an excellent postoperative exercise tolerance and the left ventricular function was preserved. The 4-year survival rates were 88% and 96% and the cardiac event-free survival rates were 74% and 87% in the SVG and IMA groups respectively. CONCLUSIONS: Complete revascularization of the diffusely diseased LAD coronary artery can be accomplished by adjunctive open endarterectomy with a degree of operative risk (mortality 9% and incidence of non-fatal myocardial infarction 7%). The immediate and medium-term results are improved when the IMA is used as a conduit, with or without additional venous patch. Independent risk factors for mortality were two-vessel endarterectomy, female sex and emergency operation. The long-term results revealed an overall survival rate of 92% and a cardiac event-free survival rate of 79% at 4 years, as well as excellent functional results.     

Anomalous origin of the right coronary artery from the left anterior descending coronary artery

A 77-year-old male presented with a recent posterior myocardial infarction for coronary angiography. This angiogram revealed a rare, previously unreported anomalous origin of the right coronary artery from the proximal left anterior descending coronary artery distal to the first major diagonal branch.     

Are directional coronary atherectomy and Palmaz-Schatz stent more efficacious than conventional balloon angioplasty for treating de novo coronary artery lesions?

It is unclear whether new devices such as directional coronary atherectomy (DCA) or Palmaz-Schatz stent implantation improve long-term outcomes compared with conventional balloon angioplasty in patients with stable angina and de novo coronary artery lesions of type A or type B except for complete occlusive lesions investigated by the American College of Cardiology/American Heart Association task force on percutaneous transluminal coronary angioplasty. A total of 146 patients with stable angina and simple lesions were assigned to either conventional balloon angioplasty (62 patients), DCA (50 patients), or Palmaz-Schatz implantation (34 patients). The acute results and late outcomes were assessed by coronary angiography. The results of the three procedures were similar with respect to procedural success and complications. Patients who underwent stenting or DCA had a larger immediate increase in the diameter of the lumen and a larger luminal diameter immediately after the procedure than those who underwent balloon angioplasty. At six months follow-up, the patients treated by stenting continued to have a larger luminal diameter and a lower rate of restenosis than those treated with balloon angioplasty (2.30 +/- 0.66 vs 1.85 +/- 0.83 mm, p < 0.005; 5.9% vs 29%, p < 0.05) and DCA (2.30 +/- 0.66 vs 1.90 +/- 0.96 mm, p < 0.05; 5.9% vs 24%, NS). The patients treated with balloon angioplasty had a smaller late loss than those treated with DCA or Palmaz-Schatz stent. The patients treated with DCA had a larger loss index than those treated with balloon angioplasty or Palmaz-Schatz stent. Stenting was a significant factor in decreasing the rate of restenosis by logistic regression analysis, compared with balloon angioplasty. The angiographic outcomes were better in patients who received a stent than in those who received other treatments. This study suggests that even lesions stable for treatment by balloon angioplasty and DCA can also be treated with Palmaz-Schatz stents.     

Comparison of transesophageal coronary sinus and left anterior descending coronary artery Doppler measurements for the assessment of coronary flow reserve

Genetic variation in correlations among size-related traits of head, thorax, and wings was examined in Drosophila buzzatii, by comparing the pattern of the Phenotypic Correlation Matrix (Rp) between inversion karyotypes of the second chromosome. No similarity in Rp was observed between some karyotypes in a natural population. The pattern of Rp in wild-reared heterokaryotypes, but not in homokaryotypes, was similar to the whole population represented by laboratory-reared flies. While phenotypic correlations in wild-reared flies were found to be larger than in laboratory-reared flies, similarity in the pattern of Rp was very high for one homokaryotype reared in both environments: the relatively homogeneous lab environment and the more variable field environment. While no such a similarity across environments was detected between different karyotypes, the pattern of Rp was similar for a same homokaryotype in different populations. Thus, the lack of karyotypic similarity in Rp is, at least partially, genetic. These results indicate that chromosomal inversions are factors affecting genetic correlations among traits known to be phenotypically correlated with adult fitness components in this species.     

Noninvasive assessment of significant left anterior descending coronary artery stenosis by coronary flow velocity reserve with transthoracic color Doppler echocardiography

BACKGROUND: Coronary flow reserve has been considered an important diagnostic index of the functional significance of coronary artery stenosis. With Doppler technique, it has been assessed as the ratio of hyperemic to basal coronary flow velocity (coronary flow velocity reserve [CFVR]) by invasive or semiinvasive methods with a Doppler catheter, a Doppler guide wire, and a transesophageal Doppler echocardiographic probe. Recent technological advancement in transthoracic Doppler echocardiography (TTDE) provides measurement of coronary flow velocity in the distal portion of the left anterior descending coronary artery (LAD) and may be useful in the noninvasive CFVR measurement. The purpose of this study was to evaluate the value of CFVR determined by TTDE for the assessment of significant LAD stenosis. METHODS AND RESULTS: We studied 36 patients who underwent coronary angiography for the assessment of coronary artery disease. The study population consisted of 12 patients with significant LAD stenosis (group A) and 24 patients without significant LAD stenosis (group B). With TTDE, coronary flow velocities in the distal LAD were recorded at rest and during hyperemia induced by intravenous infusion of adenosine (0.14 mg x kg(-1) x min(-1)) under the guidance of color Doppler flow mapping. Adequate spectral Doppler recordings of coronary flow in the distal LAD for the assessment of CFVR were obtained in 34 of 36 study patients (94%). The peak and mean diastolic coronary flow velocities at baseline did not differ between groups A and B (23.6+/-10.3 versus 22.9+/-6.6 cm/s and 16.4+/-8.6 versus 14.5+/-4.0 cm/s, respectively). However, the peak and mean coronary flow velocities during hyperemia in group A were significantly smaller than those in group B (35.6+/-16.3 versus 54.2+/-16.3 cm/s and 24.7+/-13.1 versus 37.9+/-13.0 cm/s, respectively; P<.01). There were significant differences in CFVR obtained from peak and mean diastolic velocity between groups A and B (1.5+/-0.2 versus 2.4+/-0.4 and 1.5+/-0.2 versus 2.6+/-0.4, respectively; P<.001). A CFVR from peak diastolic velocity <2.0 had a sensitivity of 92% and a specificity of 82% for the presence of significant LAD stenosis. A CFVR from mean diastolic velocity <2.0 had a sensitivity of 92% and a specificity of 86% for the presence of significant LAD stenosis. CONCLUSIONS: CFVR determined by TTDE is useful in the noninvasive assessment of significant stenotic lesion in the LAD.     

Persistence of mammary artery branches and blood supply to the left anterior descending artery

BACKGROUND: Partial harvesting of the left internal mammary artery (LIMA) is a widespread technique used during minimally invasive coronary operations performed through a left anterior small thoracotomy. The influence of persisting LIMA branches was investigated to evaluate their effect on the blood flow of the left anterior descending artery. METHODS: Thirty patients, 15 with totally (group A) and 15 with partially (group B) harvested LIMAs, were evaluated. All the patients underwent postoperative angiography, during which a flow map of the LIMA was performed. The average peak velocity and the diastolic-to-systolic peak velocity ratio were recorded. The LIMA graft flow pattern was recorded in the proximal and distal thirds of the artery. Intramammary adenosine (12 to 14 microg) was injected and the average peak velocities before and after injection were calculated. RESULTS: The average peak velocity was similar in both groups in the proximal and distal thirds of the LIMA (25 +/- 7 and 26 +/- 5 cm/sec, respectively, in group A versus 27 +/- 5 and 25 +/- 5 cm/sec, respectively in group B; p = NS). The diastolic-to-systolic peak velocity ratio was similar proximally (0.78 +/- 0.3 in group A versus 0.69 +/- 0.3 cm/s in group B; p = NS), but not distally (1.72 +/- 0.1 in group A versus 0.97 +/- 0.3 in group B; p < 0.0005). The LIMA graft flow reserve was similar both proximally and distally (2.6 +/- 0.6 and 2.5 +/- 0.3 cm/s, respectively, in group A versus 2.6 +/- 0.5 and 2.6 +/- 0.3 cm/s, respectively, in group B; p = NS). CONCLUSIONS: The persistence of LIMA branches does not influence the blood flow of the left anterior descending artery after acute adenosine-induced myocardial hyperemia. If a left anterior small thoracotomy is used in left anterior descending artery direct revascularization, complete LIMA harvesting is not mandatory and depends on the personal preference of the surgeon.     

Acute dilutional anemia and critical left anterior descending coronary artery stenosis impairs end organ oxygen delivery

OBJECTIVE: Limited cardiac reserve, secondary to coronary disease, may be associated with end organ morbidity. In this study, we investigate the significance of anemia in the pathogenesis of this phenomenon. DESIGN: Nonrandomized controlled animal trial. SETTINGS: Animal laboratory in a university hospital. SUBJECT: Anesthetized dogs. INTERVENTIONS/MEASUREMENTS: Fourteen anesthetized dogs underwent isovolemic hemodilution with 6% hetastarch from a baseline hematocrit of 40 to 20%. Radioactive microspheres were used to evaluate regional blood flow and cardiac index. Systemic oxygen delivery, consumption, serum lactate, and systemic vascular resistance were recorded during each experiment. Arterial venous oxygen difference was determined from arterial and mixed venous blood. Seven dogs had an iatrogenic critical stenosis of their left anterior descending coronary artery (experimental group); seven dogs did not (control). MAIN RESULTS: Only in the control animals, the cardiac index increased by 35% with hemodilution to 20%. Systemic oxygen delivery decreased in both the control and the experimental animals. Systemic oxygen consumption and lactate levels were unchanged in both groups. In the renal cortex, spleen, distal colon, ileum, gallbladder, and stomach body, regional O2 delivery was significantly decreased with hemodilution to 20% in both groups. This finding was also observed in the left ventricle and cervical spinal cord in the experimental group. In addition, regional O2 delivery was reduced in the spleen, distal colon, and gallbladder with hemodilution to only 30%. Regional blood flow in the stomach body, gallbladder, ileum, renal cortex, and distal colon, in both groups, and the spleen in the control group was unchanged from baseline with hemodilution to 20%. However, regional blood flow under all other circumstances (control or experimental) was significantly increased with hemodilution to 20% with the exception of the spleen, which showed significant regional blood flow decrease in the experimental group only. CONCLUSIONS: These data suggest that with limited cardiac reserve, anemia may compromise aerobic splanchnic circulation. These observations may further our understanding of the pathogenesis of cholecystitis, gastric stress ulcers, ileal endotoxin translocation, and ischemic colitis in critically ill patients with coronary artery disease.     

Noninvasive assessment of coronary flow velocity and coronary flow velocity reserve in the left anterior descending coronary artery by Doppler echocardiography: comparison with invasive technique

OBJECTIVES: The purpose of this study was to evaluate whether transthoracic Doppler echocardiography (TTDE) can reliably measure coronary flow velocity (CFV) and coronary flow velocity reserve (CFVR) in the left anterior descending coronary artery (LAD) in the clinical setting. BACKGROUND: Coronary flow velocity measurement has provided useful clinical and physiologic information. Advancement in TTDE provides noninvasive measurement of CFV and CFVR in the distal LAD. METHODS: In 23 patients, CFV in the distal LAD was measured by TTDE (5 or 3.5 MHz) under the guidance of color Doppler flow mapping at the time of Doppler guide wire (DGW) examination. Coronary flow velocity in the distal LAD were measured at baseline and hyperemic conditions (intravenous administration of adenosine 0.14 mg/kg/min) by both TTDE and DGW techniques. Coronary flow velocity reserve was defined as the ratio of peak hyperemic to basal averaged peak velocity in the distal LAD. RESULTS: Clear envelopes of basal and hyperemic CFV in the distal LAD were obtained in 18 (78%) of 23 study patients by TTDE. There were excellent correlations between TTDE and DGW methods for the measurements of CFV (averaged peak velocity: r=0.97, y=0.94x + 0.40; averaged diastolic peak velocity: r=0.97, y=0.94x + 0.69; systolic peak velocities: r=0.97, y=0.91x + 0.87; diastolic peak velocity: r=0.98, y=0.95x + 1.10). Coronary flow velocity reserve from TTDE correlated highly with those from DGW examinations (r=0.94, y=0.95x + 0.21). CONCLUSIONS: Noninvasive measurement of CFV and CFVR in the distal LAD using TTDE accurately reflects invasive measurement of CFV and CFVR by DGW method.     

Ischemia-associated intraventricular conduction disturbances during exercise testing as a predictor of proximal left anterior descending coronary artery disease

To determine the incidence and significance of transient intraventricular conduction abnormalities occurring in association with myocardial ischemia during exercise testing, the recordings of 2,200 consecutive exercise tests were reviewed. Ten patients (0.45%) were identified as having both ischemia and intraventricular conduction abnormalities that developed transiently during the exercise test. In all 10 patients both typical angina and electrocardiographic evidence of ischemia developed during exercise. Among the 10 patients, left anterior hemiblock developed in 4, left posterior hemiblock in 2, right bundle branch block (RBBB) in 2, RBBB with left axis deviation in 1, and left anterior hemiblock progressing to complete left bundle branch block (LBBB) in 1. All 10 patients had cardiac catheterization showing significant obstruction of the left anterior descending (LAD) coronary artery at or before the origin of the first septal branch. Eight patients were treated surgically and 2 medically, all with relief of ischemic symptoms. Nine of the 10 had repeat exercise stress testing without angina or electrocardiographic evidence of ischemia and without recurrence of the transient intraventricular conduction disturbance. It is concluded that the development of transient intraventricular conduction abnormalities associated with myocardial ischemia during exercise testing is an uncommon occurrence (0.45%). When such conduction disturbances do develop, the existence of significant disease in the proximal portion of the LAD coronary artery is strongly suggested. With control of myocardial ischemia, the transient conduction disturbances during exercise are ameliorated.     

Significance of development of late potentials after anterior wall acute myocardial infarction despite successful primary angioplasty of the left anterior descending coronary artery

We classified 33 patients with a first anterior infarction and single-vessel disease who had undergone successful primary angioplasty and had a patent infarct-related artery into groups based on the development of late potentials. Left ventricular function improved between 1 and 3 months after angioplasty only in patients without late potentials; the development of late potentials after acute anterior infarction was associated with prolonged left ventricular dysfunction despite successful revascularization with primary angioplasty.     

Location of stents in the left anterior descending coronary artery using three dimensionally acquired, two dimensionally displayed transthoracic echocardiography

The location of left anterior descending arterial stents was documented in 10 of 13 patients using 3-dimensionally acquired, 2-dimensionally displayed transthoracic echocardiography. The echocardiographic appearance of stents was characterized, and the location of the proximal and mid-left anterior descending artery was objectively documented.     

Stent recoil: comparison of the Wiktor-GX coil and the Palmaz-Schatz tubular coronary stent

Wiktor-GX coil stents and Palmaz-Schatz 154A tubular stents were implanted in a consecutive series of 40 patients and 45 arteries undergoing successful primary stent placement in de novo lesions treated with single stents in order to compare the acute recoil of a coil stent to a tubular stent in native coronary arteries. Acute stent recoil was determined by measuring the difference between the maximum inflated diameter of the stent deployment balloon and the minimum lumen diameter after stent deployment. There was no difference between the two groups for reference vessel diameter, nominal balloon diameter, maximum inflated balloon diameter, maximum inflation pressure, or poststent vessel minimum lumen diameter. Acute recoil averaged 0.15 +/- 0.2 mm for the Wiktor-GX and 0.13 +/- 0.1 for the Palmaz-Schatz (P = 0.58). In this series of patients, there was no significant difference between the acute recoil of the coil stent compared to the tubular stent.