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Minimally invasive LAD revascularisation in high-risk patients with three-vessel coronary artery disease.

OBJECTIVE: A potential advantage of minimally invasive direct coronary artery bypass (MIDCAB) is that patients in whom conventional coronary bypass surgery is associated with increased risk because of various associated medical conditions, or those with relative contraindications to cardiopulmonary bypass, can benefit from surgical revascularisation. We reviewed our experience with adopting MIDCAB in the management of patients with three-vessel coronary artery disease over an 8 month period. METHODS: Thirteen patients (3 females, mean age 67.6 years) with severe symptomatic three vessel coronary artery disease on maximum medical treatment (angina class III or IV) received left internal mammary artery grafts to the left anterior descending coronary artery using the MIDCAB approach. Associated co-morbidity included: severe chronic renal failure (n=2), severe extensive arteriopathy (n=4), chronic obstructive airway disease (n=2), poor general condition (n=2) and severely impaired left ventricular function (n=3). RESULTS: There was one early postoperative mortality and no other cardiac related morbidity. All patients were extubated within 3 h of leaving the operating room, mean ITU stay was 15 h and mean hospital stay was 5 days. Graft patency was investigated using angiography in all patients; all grafts but two were patent. In combination with medical therapy, all patients remain entirely angina free at a follow-up period between 3-11 months. CONCLUSIONS: MIDCAB is an effective approach for managing high-risk patients with symptomatic three-vessel coronary artery disease. Longer follow-up is needed to further clarify patient selection and the long-term outcome of this approach.

Aged↗

Magnetic resonance imaging of the coronary vessel wall at 3 T using an obliquely oriented reinversion slab with adiabatic pulses.

Three-dimensional methods offer volumetric coverage in coronary vessel wall imaging, in addition to high signal-to-noise ratios (SNR). To increase SNR further, it is desirable to implement such 3D methods at 3 T. At this field strength, the pulse sequence must be robust to main field and RF inhomogeneities. To achieve this, the double inversion-recovery (DIR) preparation was adapted to use adiabatic pulses, with a slab-selective reinversion replacing the previously used 2D pencil-beam. The slab was oriented obliquely, in order to avoid upstream blood (e.g., left ventricle) or the navigator beam. Phantom experiments suggest that at 3 T, this approach improves both the net profile of the DIR pulse pair and the restoration of magnetization in the navigator region. Using this method, the feasibility of 3D coronary vessel wall imaging was demonstrated at 3 T. Fourteen healthy subjects were scanned using a segmented gradient-echo sequence with prospective navigator gating. Good-quality images of left and right coronary arteries were obtained, with SNR values of 29.7 +/- 7.5 (vessel wall); 10.5 +/- 4.4 (blood); 14.3 +/- 5.2 (fat); and 45.6 +/- 18.0 (myocardium). No problems occurred with ECG-gating or power deposition (SAR) limits.

Adult↗

[Global change in the regulation of regional coronary flow in patients with single vessel coronary disease evidenced by positron emission tomography].

AIM OF THE STUDY: Aim of this study is to investigate whether, in patients with coronary artery disease (CAD), regional myocardial blood flow (rMBF) regulation is affected with further mechanisms besides the effects of epicardial coronary stenosis. MATERIAL AND METHODS: RMBF and coronary reserve are measured in 13 normal subjects and in 36 patients with effort angina and isolated (> or = 50% diameter narrowing) left anterior descending (LAD, 27 patients) or left circumflex (LCX, 9 patients) coronary artery stenosis. Measurements are obtained both at baseline and following dipyridamole (0.56 mg/kg in 4 minutes) using positron emission tomography and N13-ammonia. RESULTS: At rest, patients with CAD show similar rMBF values in the stenotic and remote areas (0.71 +/- 0.19 vs 0.77 +/- 0.22 ml/min/gr, respectively, ns); both values are significantly (p < 0.01) reduced with respect to mean rMBF observed in the normal subjects (1.07 +/- 0.21 ml/min/gr). Following dipyridamole, patients with CAD show lower rMBF values in stenotic than in control regions (1.25 +/- 0.54 vs 1.73 +/- 0.80 ml/min/gr, p < 0.01); however, both these values are significantly reduced when compared with mean rMBF in the normal subjects (3.76 +/- 0.88 ml/min/gr, p < 0.01). To evaluate whether reduction in resting myocardial perfusion indicates maximal vasodilatation, patients with CAD are divided into 2 groups: Group 1 with homogeneous baseline perfusion (0.73 +/- 0.2 vs 0.75 +/- 0.24 ml/min/gr, in stenotic and remote areas, respectively, ns), and Group 2 with baseline perfusion defect in the stenotic related territory (0.62 +/- 0.14 vs 0.84 +/- 0.17 ml/min/gr, p < 0.01). Coronary reserve (dipyridamole flow/baseline flow) is similar in the 2 Groups (1.74 +/- 0.66 vs 1.93 +/- 0.45, ns). CONCLUSIONS: These data suggest that, in patients with CAD, other factors beyond hydraulic effects of epicardial coronary stenosis, could modulate rMBF regulation; in fact: 1) myocardium perfused by angiographically normal coronary artery shows reduced values of both resting rMBF and coronary reserve; 2) myocardium supplied by stenotic vessel maintains a residual vasodilating capability despite a reduced baseline perfusion.

Aged↗

[Autoregulation of coronary vessels following the acute blood loss and its combination with preexisting immobilization stress].

A 6-hour immobilization stress and a 2-hour posthaemorrhagic hypotension caused elevation of the coronary flow, deterioration of coronary autoregulation, decreasing of the coronary dilation reserve, and diminishing of the left ventricular pressure. In the "stress + haemorrhage" group, the changes of the coronary vessels autoregulation ability were less obvious. Concentration of NO3-/NO2- in the blood serum was elevated after stress. Inhibition of the NO-synthase decreased the coronary flow. Thereupon, a pre-existing immobilization stress alters the coronary vessels tone.

Animals↗

One-vessel coronary artery disease. Anatomic, functional, and prognostic considerations.

Patients with one-vessel coronary artery disease (CAD) constitute a heterogenous group with regard to anatomy, pathophysiology, and prognosis. Noninvasive examination of these patients shows variation in the presence and magnitude of ST-segment depression, the presence and extent of exercise-induced thallium 201-perfusion defect, and the presence and extent of regional and global left ventricular dysfunction assessed by radionuclide angiocardiography. Further studies, however, are needed to determine whether the physiologic consequences assessed noninvasively compound the effects of coronary anatomy as defined by angiocardiography on the prognosis or whether they are independent of these effects. Percutaneous transluminal coronary angioplasty should be considered in patients with one-vessel CAD who are symptomatic or in those who have a large amount of jeopardized myocardium.

Angiocardiography↗

[Implantation of the Palmaz-Schatz stent in coronary vessels irrigating and non-irrigating necrotic myocardial areas: comparison of acute results and at mid-term].

Recent evidence suggests that higher restenosis rate is observed after coronary angioplasty of an infarct-related artery. Furthermore, angiographic restenosis seems associated with a deterioration of left ventricular function at follow-up. The aim of this study was to assess the acute results and angiographic restenosis following coronary artery stenting of infarct-related (Group 1) and non infarct-related coronary arteries (Group 2). We retrospectively analyzed the results of 381 consecutive patients treated with Palmaz-Schatz coronary stent implantation between May 1992 and January 1996. Stenting of the infarct-related artery was performed in 154 patients (Group 1), while 227 patients (Group 2) received stenting of the non infarct-related artery. Both groups had similar age, gender, clinical conditions and coronary angiographic pattern. There were no significant differences between groups, concerning type of stented coronary vessel (left anterior descending-LAD 52.4% vs non-LAD 47.6%, Group 1, LAD 59.5% vs non-LAD 40.5%, Group 2) and number of stents per patient (1.31 +/- 0.48 in Group 1, 1.18 +/- 0.56 in Group 2) and per coronary vessel (1.17 +/- 0.54 in Group 1, 1.09 +/- 0.46 in Group 2). The procedure was performed using similar maximal inflation pressures in both groups (13.3 +/- 2.9 atm in Group 1, 13.40 +/- 3.17 atm in Group 2). Technical success was achieved in 96.8% of Group 1 and in 96% of Group 2 patients. Acute coronary stenting success and major adverse events (acute myocardial infarction, emergency bypass, death) were similar in both groups of patients. No difference was found in restenosis rate at 6-month angiographic follow-up (Group 1 = 29.8%, Group 2 = 27%). In conclusion, this study indicates that stenting of infarct and non infarct-related coronary arteries has similar success and 6-month restenosis rates.

Coronary Circulation↗

Normothermic ischaemic arrest in one-vessel coronary artery surgery.

Cardiac metabolism following normothermic ischaemic arrest was studied in 14 patients undergoing coronary bypass surgery for single vessel coronary artery disease. Simultaneous blood samples were taken from the radial artery and from the coronary sinus before and during the first 60 min after aortic crossclamping. O2-saturation and content, potassium, lactate and the isoenzyme MB of the creatine kinase (CK-MB) were assessed. In addition, CK-MB was followed in peripheral venous blood for 8 hours after operation. Analysis of the results revealed decreased oxygen extraction by the heart immediately after the release of the aortic crossclamping and marked lactate and potassium release with delayed metabolic recovery of the myocardium despite the very short aortic occlusion time. Increased postoperative CK-MB serum activity was also seen. We concluded that the use of normothermic ischaemic arrest is hazardous even in such surgical procedures requiring aortic occlusion times as short as 15 min and should be avoided at least by the less experienced surgeon.

Coronary Artery Bypass↗

Comparative study of on-pump and off-pump coronary bypass surgery in patients with triple-vessel coronary artery disease.

BACKGROUND: Studies on selected patients undergoing off-pump versus on-pump coronary artery bypass surgery have produced inconsistent results, especially in patients with multiple coronary artery disease. This study compared the clinical results of on-pump and off-pump coronary bypass surgery in patients with triple-vessel disease. METHODS: A total of 300 consecutive isolated, multiple coronary artery bypass grafting (CABG) patients were assigned to the off-pump coronary artery bypass (OPCAB, n = 150) or CABG with cardiopulmonary bypass (CCABG, n = 150) groups. There were no significant differences regarding degree of angina, history of myocardial infarction or diabetes, and presence of left main coronary artery disease between the two groups. Ejection fraction in the OPCAB group before surgery was lower than in the CCABG group (P < 0.01). In addition, more patients had a history of stroke and abnormal renal function preoperatively in the OPCAB group (P < 0.01). In OPCAB patients, single deep pericardial stay suture with a sling snared down was used to expose the target vessels, along with a stabilizer and a coronary shunt. A Medi-Stim Butterfly Flowmeter was used to measure blood flow through grafts in both groups. RESULTS: No OPCAB patient was converted to the CCABG group. The average numbers of distal anastomoses and the indexes of completeness of revascularization (ICR) were similar in both groups. Postoperative respiratory support time and the volumes of chest tube drainage and of blood transfusions were less in the OPCAB group than in the CCABG group (both P < 0.01). The postoperative incidences of pulmonary dysfunction and renal insufficiency were lower in the OPCAB group than in the CCABG group (both P < 0.05). There were no significant differences between the two groups in mortality and other causes of morbidity (perioperative myocardial infarction, stroke, atrial fibrillation). CONCLUSIONS: OPCAB can be applied to patients with triple-vessel coronary artery disease and can achieve similar completeness of revascularization and similar early surgical results, with shorter respiratory support, reduced transfusion requirement, and fewer cases of pulmonary dysfunction and abnormal renal function.

Aged↗

Relation between exercise and dobutamine stress-induced wall motion abnormalities and severity and location of stenosis in single-vessel coronary artery disease.

BACKGROUND: Quantitative coronary angiography has been shown to allow accurate assessment of coronary stenosis. Exercise and dobutamine stress echocardiography both are established methods for assessing the functional importance of coronary stenosis. The relation, however, between exercise and dobutamine stress-induced wall motion abnormalities and the severity and location of stenosis remains controversial. METHODS AND RESULTS: Thirty patients with single-vessel coronary artery disease with >/=50% minimal luminal reduction and stable angina participated in the study. Severity of coronary artery stenosis was assessed by means of computed angiography. During peak exercise echocardiography 23 patients had wall motion abnormalities and 7 did not. A positive test result was associated with severity of stenosis >/=80% for 65% of stenoses (P <.05 versus severity of stenosis <80%) and with a proximal location of 94% of stenoses (P <.01 versus middle and distal stenoses). A significant correlation was found between area of stenosis and difference in wall motion score between rest and peak exercise (r = 0.53, P <.01). The proportion of positive exercise stress was greater among stenoses with severity <80% (62% versus 46% dobutamine stress, P <.05). During dobutamine stress echocardiography 18 patients had wall motion abnormalities and 12 patients did not. A positive test result was associated with severity of stenosis >/=80% in 72% of stenoses (P <.05 versus severity of stenosis <80%) and with a proximal location in 81% of stenoses (P <.01 versus middle and distal stenoses). A weak correlation was found between area of stenosis and difference in wall motion score between rest and peak dobutamine stress (r = 0.37, P <.05). CONCLUSIONS: Among patients with single-vessel coronary artery disease, positive stress echocardiographic test results usually are associated with proximal >/=80% stenosis. Patients with <80% stenoses are more likely to have a positive exercise stress test result than a positive dobutamine stress test result.

Cardiotonic Agents↗

Angioplasty induced myocardial ischaemia prolongs the signal-averaged P-wave duration in single vessel coronary artery disease.

Aims The P-wave duration (PWD) has been shown to prolong in conditions associated with elevated left ventricular end-diastolic and left atrial pressures, which also increase during transient coronary artery occlusions such as angioplasty. The aim of this study was to investigate the effects of angioplasty-induced myocardial ischaemia on signal averaged PWD in patients undergoing coronary angioplasty. Methods Eighty-four consecutive adult patients with single-vessel coronary artery disease undergoing elective coronary angioplasty were included. Duration of the P wave before and during coronary angioplasty were evaluated using signal averaged P-wave analysis. Patients were classified in groups according to the artery occluded, as left anterior descending (LAD) Group, right coronary artery (RCA) Group or Others Group (which included obtuse marginal, circumflex or diagonal). Results Patients included in the LAD, RCA and Others groups were similar with respect to clinical characteristics. The mean PWD at baseline was similar in all lesions (P>0.05), whereas mean PWD at inflation was significantly longer in LAD Group compared with RCA (126.1 +/- 9.5 ms vs 118.7 +/- 10.4 ms, P=0.007) and Others (126.1 +/- 9.5 ms vs 116.3 +/- 8.6 ms, P<0.001). The PWD during balloon inflation was significantly prolonged in all groups compared with baseline levels (LAD Group 126.1 +/- 9.6 ms vs 109.7 +/- 8.0 ms; RCA Group 118.7 +/- 10.4 ms vs 108.3 +/- 8.4 ms and Others Group 116.3 +/- 8.6 ms vs 109.7 +/- 6.0 ms, all P values <0.001). Conclusion Signal-averaged PWD significantly increases during single-vessel coronary angioplasty. This increase is more pronounced for LAD lesions. However, the clinical implications of P-wave prolongation during balloon angioplasty and the value of PWD as a measure of ischaemia remains to be clarified.

Angioplasty, Balloon, Coronary↗

Endothelial dysfunction in coronary vessels and thoracic aorta of rats exposed to cigarette smoke.

1. The aim of this study was to evaluate the role of endothelium in mediating the response to acetylcholine in the thoracic aorta and coronary vessels of rats exposed to cigarette smoking. Total serum cholesterol was measured at the beginning and end of the experiment. 2. The relaxation response to acetylcholine was significantly impaired in the aortae of rats exposed to cigarette smoking (P < 0.05); and the coronary flow during the administration of acetylcholine (0.02 microgram/min.) was significantly reduced (P < 0.05). The total cholesterol plasma levels increased 31.13% in those exposed to smoke when compared to the controls (P < 0.05). 3. It is concluded that exposure to cigarette smoking increases total serum cholesterol levels, and also produces primary endothelial dysfunction in aorta rings and coronary vessels.

Acetylcholine↗

Effects of a comprehensive rehabilitation programme in patients with three-vessel coronary disease.

The aim of the study was to assess the effects of rehabilitation in 46 consecutive three-vessel coronary disease patients who were considered to have no possibility of revascularization; there were 45 males and one female (mean age 58) sent in the third week after acute myocardial infarction (N = 31) or after unstable angina (N = 15). Left ventricular ejection fraction (EF) was normal in 50% of the patients, but 15% had an EF less than or equal to 0.30. Three patients could not begin their rehabilitation because of unstable angina (N = 2) or severe pulmonary oedema (N = 1). After a 4-week rehabilitation programme, the comparison of stress tests revealed an increase in functional capacities (maximal work-load = 103.6 +/- 27 W before rehabilitation, 126.4 +/- 31 W after rehabilitation, P less than 0.001), and an improvement of the ischaemic threshold [82 +/- 32 W before rehabilitation, 91 +/- 31 W after rehabilitation, P less than 0.05]. During long-term follow up [20.8 months], four patients died of cardiac events [8.7%]; all of them had an EF less than 0.45. Among the 42 living patients 61.9% were asymptomatic, 28.7% had exertional angina, and 9.4% had cardiac complications, and coronary surgery was performed in two cases with good results. The level of return to work was 85% with the mean delay of 1.7 months after rehabilitation. So, rehabilitation in three-vessel coronary disease patients is safe under medical control; improvements in exertional capacities are obvious and give the patients a better self confidence as assessed by the good score of return to work after rehabilitation.

Angina Pectoris↗

Outcome in one-vessel coronary artery disease.

We analyzed the clinical outcomes in 688 patients with isolated stenosis of one major coronary artery. The survival rate among patients with disease of the right coronary artery (RCA) was higher than that among patients with left anterior descending (LAD) or left circumflex coronary artery (LCA) disease. The survival rate among patients in all three anatomic subgroups exceeded 90% at 5 years. The presence of a lesion proximal to the first septal perforator of the LAD was associated with decreased survival compared with the presence of a more distal lesion. For the entire group of one-vessel disease patients, total ischemic events (death and nonfatal infarction) occurred at similar rates regardless of the anatomic location of the lesion. Left ventricular ejection fraction was the baseline descriptor most strongly associated with survival, and the characteristics of the angina had the strongest relationship with nonfatal myocardial infarction. No differences in survival or total cardiac event rates were found with surgical or nonsurgical therapy. The relief of angina was superior with surgical therapy, although the majority of nonsurgically treated patients had significant relief of angina. The survival rate of patients with one-vessel coronary disease is excellent, and the risk of nonfatal infarction is low. Clinical strategies for the care of these patients must consider the long-term clinical course of one-vessel coronary disease.

Angina Pectoris↗