摘要:

Background Dynamic cardiomyoplasty remains a promising but poorly understood surgical modality for selected patients with dilated cardiomyopathy.Despite encouraging clinical results, objective evidence of enhanced ventricular function using traditional indexes (cardiac output, ejection fraction, and dP/dt) has been difficult to document after cardiomyoplasty. Several investigators have suggested that cardiomyoplasty acts partly by unloading the left ventricle. These indexes all depend somewhat on loading conditions, however, and might not detect such an interaction. The time-varying elastance model provides an index of contractility, Emax, that is relatively insensitive to changes in loading conditions. We applied this model to study the effect of right latissimus dorsi cardiomyoplasty on left ventricular function in an acute canine model.Methods and Results Five dogs underwent acute cardiomyoplasty using untrained right latissimus dorsi muscle.Instrumentation included Millar pressure transducers in the left ventricle and aortic root, an electromagnetic flow probe around the ascending aorta, and a volume conductance catheter in the left ventricle. A cuffed nerve electrode around the thoracodorsal nerve and a right ventricular sensing lead were connected to a Medtronic Cardiomyostimulator (5 V, 30 Hz, 1:1 synchronization). Transient caval occlusions were performed with the stimulator both off and on to calculate Emaxand the slope of the end-systolic pressure-volume relationship (Ees). Turning the stimulator on significantly increased peak systolic elastance (Emax) and end-systolic elastance (Ees) in all five dogs by an average of 56% and 78%, respectively (P<.05). End-diastolic volume and end-systolic volume decreased by 18% and 28%, respectively (P<.05). All other measured hemodynamic parameters, including peak left ventricular pressure, mean arterial pressure, cardiac output, stroke volume, stroke work, ejection fraction, preload-recruitable stroke work, and dP/dt, did not change significantly.Conclusions These results show that, in this acute canine model, right latissimus dorsi cardiomyoplasty significantly improves left ventricular function while decreasing left ventricular volumes.The results are consistent with the theory that cardiomyoplasty increases contractility while unloading the ventricle by decreasing end-diastolic volume. This increase in Emaxdespite inconsistent changes in other indexes underlies the importance of using load-insensitive indexes of ventricular function when studying cardiomyoplasty. (Circulation. 1994; 90(part 2):II-112-II-119.)

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Background In a randomized study of unstable angina, medically treated patients with impaired left ventricular (LV) ejection fractions (EF=0.3 to 0.58) were at significantly higher risk of mortality than patients treated by coronary artery bypass graft surgery (CABG). Because the duration of this surgical advantage is unknown, 10-year cumulative mortality rates of patients with impaired LVEF were determined and compared with the previously observed rates at 2, 5, and 8 years.Methods and Results Of 468 patients with unstable angina, 237 were randomized to receive medical treatment alone and 231 patients to have CABG.Baseline characteristics, which were equally distributed between the two treatment groups, included age, LVEF, number of diseased coronary arteries, diabetes, clinical presentation (type I or type II), prior myocardial infarction, and smoking. Mortality was determined by life-Table analysisand risk factors by logistic regression analysis. Patients were divided into terciles according to LVEF, and the mortality rates of medical and surgical patients in the lowest tercile were compared. The 10-year mortality rate for all medical patients was 38% and for all surgical patients, 39%. When LVEF was treated as a continuous variable, there was a significant relation between mortality and LVEF for medically treated patients but not for surgical patients. The cumulative mortality rate for the lowest-tercile (EF 0.3 to 0.58) medical patients was 49%; for the lowest-tercile surgical patients, 41% (P=.15).Conclusions The surgical advantage for patients with impaired LVEF that was significant at 5 years (P=.03) and 8 years (P=.05) appears to have diminished at 10 years (P=.15). (Circulation. 1994;90(part 2):II-120-II-123.)

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Background Procedure-related costs are of increasing concern in selecting the appropriate procedure for the treatment of coronary artery disease (CAD).Methods and Results To determine what preoperative factors influence total postoperative hospital costs, data on 604 coronary artery bypass graft surgery (CABG) patients from 1990 to 1991 were analyzed.Professional fees were excluded. Hospital costs were computed by multiplying patient charges by the Medicare cost-to-charge ratio used in determining federal reimbursement. Median postoperative cost was $12 912 (range, $7100 to $259 546). Data were analyzed with a semiparametric regression model. Patients dying in the hospital were censored at time of death. There were significant differences among surgeons in costs but no significant differences in operative mortality. Significant risk factors for increased cost after adjusting for surgeon were: older age (P<.0001), lower left ventricular ejection fraction (P<.0001), prior CABG (P<.0001), female sex (P<.0049), no prior percutaneous transluminal coronary angioplasty (P<.0091), increased degree of CAD (P<.0102), black race (P<.0190), and diabetes (P<.032).Conclusions These results suggest that preoperative characteristics have important economic and medical implications.Surgeons should compare their management strategies on the basis of data analysis to determine the most effective practice with regard to mortality and cost. (Circulation. 1994;90(part 2): II-124-II-128.)

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Background The early and late patency of the left internal thoracic artery (LITA) has been studied thoroughly, but less is known about coronary artery bypass grafts constructed from the right internal thoracic artery (RITA).Methods and Results Between January 1984 and March 1991, 413 patients on two surgical services had bilateral arteries or RITAs used as conduits for coronary artery revascularization.Sixty-seven patients (16%; 57 male and 10 female; mean age, 59 years) had graft angiography performed up to 97 months after operation (average, 27 months). In 38 patients, angiography was performed because of angina or other objective evidence of myocardial ischemia. For all 67 patients evaluated, patency of RITA grafts was 86% (58/67), and patency of LITA grafts was 89% (57/64). For grafts to the left anterior descending (LAD) coronary artery, overall patency was 90% (58/64), and there was little difference in patency of the RITA (93%, 28/30) versus the LITA (88%, 30/34). In contrast, the overall patency rate for internal thoracic arteries used to bypass vessels other than the LAD was 76% (45/59, P<.03 versus LAD); for these bypasses to arteries other than the LAD, RITA patency was 74% (26/35), and the patency of LITA grafts was 79% (19/24). Patency of RITA grafts routed through the transverse sinus was similar to patency of other bypasses to non-LAD vessels. Among 12 free grafts that used segments of the RITA, 10 were patent (83%). Of additional saphenous vein grafts, 69% (39/56) were patent at restudy.Conclusions This study supports the continued use of the RITA as a conduit for coronary artery revascularization.In our experience, the position of the target vessel is a more important determinant of graft patency than the side of the internal thoracic artery selected for use as a bypass graft. (Circulation. 1994;90(part 2):II-129-II-132.)

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Between January 1970 and December 1991, 201 patients <=40 years of age underwent coronary artery bypass graft surgery (CABG). Group 1 (1970 to 1980, n=119) and group 2 (1981 to 1991, n=82) corresponded to the eras before and after the onset of percutaneous transluminal coronary angioplasty (PTCA), respectively, and were analyzed for trends in patient profile, treatment, and risk factors for coronary artery disease (CAD): smoking, hypertension, hypercholesterolemia, diabetes, and family history. Mean age at operation was similar in the groups (1, 37+-3.4 years; 2, 36+-3.1 years). Women made up 18% of group 1 and 27% of group 2 (P=.048). Risk factor profile differed in the two groups: group 1 had more smokers (80%) than group 2 (68%) (P=.085), fewer patients with hypercholesterolemia (1, 37%; 2, 52%; P=.065), and significantly fewer diabetics (1, 10%; 2, 25%; P<.043). Mean preoperative New York Heart Association (NYHA) class was 3.2 in group 1 and 3.0 in group 2. The distributions of single-, double-, and triple-vessel CAD were similar in the groups. Preoperative myocardial infarction occurred in 55% of group 1 versus 61% in group 2 (P=NS). No group 1 patient received PTCA before CABG, but PTCA was performed in 15 group 2 patients. Left internal mammary artery grafts were used in 4% of group 1 and 57% of group 2 patients. CABG operative mortality was 7.0% in group 1 and 1.2% in group 2. Actuarial survivals 5 and 10 years after CABG were similar in the groups: 86% and 77% in group 1 versus 91% and 70% in group 2 (P=.74). Twenty-year actuarial survival for the entire series was 40%. Late NYHA class was 1.8+-1.1 in group 1 and 1.55+-0.94 in group 2 (P=NS). Fifty-two percent of group 1 and 64% of group 2 returned to work. Forty percent of group 1 smokers and 36.5% of group 2 continued to smoke. Among 22 patient- and treatment-related variables subjected to a Cox proportional-hazards multivariate regression analysis, the only significant predictors of late mortality were left main CAD and diabetes mellitus, and only diabetes and era of operation predicted intervention-free survival. This retrospective review of young CABG patients demonstrates that (1) 10-year survival after CABG has not changed over the past 20 years, (2) the proportion of young women undergoing CABG is increasing, (3) diabetes is increasingly prevalent, and (4) severity of CAD and LV dysfunction is unchanged despite the advent of PTCA. (Circulation. 1994;90(part 2):II-133-II-139.)

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Background We assessed the improvement in total and cardiac-related operative mortality in 131 consecutive patients after reoperative coronary artery bypass surgery (CABG).Methods and Results The patients were divided into two consecutive groups, A (1988 to 1989) and B (1990 to 1993), on the basis of the implementation of alternative techniques of myocardial protection.The techniques in group B included the "no touch" technique or minimal dissection before bypass, routine femoral artery and vein exposure, and frequent cannulation for cardiopulmonary bypass and antegrade and retrograde blood cardioplegia, with all vascular anastomoses (proximal and distal) performed with a single aortic cross- clamp and cardioplegic arrest. Cardiac mortality from low cardiac output or myocardial infarction was 15% versus 0%, P=.002. Multivariate analysis of demographics, perioperative risk factors, and myocardial protection techniques revealed that only membership in group A and the requirement for an intra-aortic balloon counterpulsation independently predicted mortality. By univariate analysis, group A had significantly more patients with three-vessel disease and patients who required urgent or emergent procedures, but analysis of patients in these subgroups also demonstrates a significant reduction in mortality in the "no touch" patients (group B). Although no technique was independently responsible for reduced operative mortality, all the myocardial protection techniques implemented in group B combined to reduce the risk of reoperative CABG.Conclusions With appropriate myocardial protection techniques, the risk of reoperative CABG should be similar to that for a primary procedure.(Circulation. 1994;90(part 2): II-140-II-143.)

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Background Internal thoracic artery (ITA) conduits are known to provide long-term patency and increased patient survival with low morbidity after coronary artery bypass grafting (CABG). Excellent clinical results with the ITA have stimulated interest in additional arterial grafts.Methods and Results To review our experience and evaluate postoperative complications associated with these new conduits, from May 1985 to September 1993, we studied 290 patients who underwent CABG using additional arterial conduits.The right gastroepiploic artery (GEA) was used in 152 patients and the inferior epigastric artery (IEA) was used in 130 patients. Eight patients with both GEA and IEA grafts were excluded. Patient records were analyzed as to preoperative characteristics, angiographic findings, operative data, and postoperative complications. Statistical analysis was done using the Pearson chi squared (chi2) statistic and the t test. Ninety-eight percent of patients received one concomitant ITA graft, and the majority of patients in both groups had bilateral ITA grafts. The GEA group had a higher proportion of reoperations (GEA group, 54%; IEA group, 16%; P<.001), previous myocardial infarction (MI) (GEA group, 67%; IEA group, 50%; P=.004) and New York Heart Association class IV (GEA group, 28%; IEA group, 6%; P=.001). The IEA group was generally slightly older (IEA group, 56 years; GEA group, 52 years; P=.001). Hospital mortality (GEA group, 4%; IEA group, 0.8%) and postoperative morbidity (mediastinal bleeding, infection, stroke, MI, and low cardiac output) were not significantly different between the two groups or from our experience with routine CABG using the ITA. Three intra- abdominal complications occurred in the GEA group: 2 episodes of bleeding and 1 of pancreatitis. One patient in the IEA group had abdominal wall bleeding. With overall short follow- up, angiographic patency in a small number of patients has been good: 80% for the GEA group and 85.7% for the IEA group.Conclusions We conclude that the morbidity associated with these additional arterial conduits is low and is comparable with that associated with routine CABG using the ITA.Currently we use the ITA for primary targets and alternative arterial conduits for vessels of secondary importance or when the ITA and/or saphenous vein is not available. (Circulation. 1994;90(part 2):II-144-II-147.)

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Background Attempts to improve late results of bypass coronary surgery have focused on the use of arterial conduits because of the high attrition rate of venous grafts.Methods and Results In our institution, 150 patients received an inferior epigastric artery (EPIG) as a free bypass graft, anastomosed to the right coronary artery in 73% and to a marginal branch in 20% of cases.These patients were followed prospectively by qualitative and quantitative angiography. Angiographic studies were performed in 122 patients (81%) early after surgery (11+-5 days), and in 72 cases, a late evaluation (11+-6 months) was also obtained. Quantitative angiography (basal and after isosorbide dinitrate (ISDN)) was performed on the in situ EPIG in a large subset of these patients, as well as in 59 patients before bypass surgery. The patency rate was 98% at early control and remained high (93%) at late control. However, at late control, 14 EPIGs were occluded or threadlike, but of these 14, eight were grafted on a coronary artery with a moderate stenosis (<=60%) and with good anterograde perfusion. Mean basal EPIG diameter increased from 2.23+-0.42 mm before surgery to 2.57+-0.52 mm at 11 days (P<.01) but decreased to 2.20+-0.47 mm in late study (P<.01 versus 11 days and P=NS versus before surgery). Vasodilation of EPIG with ISDN was observed before surgery (+0.34+-0.20 mm, P<.001) and at late control (+0.20+-0.17 mm, P<.001) but not in the early postoperative period for the whole group. Early after surgery, basal diameter was not different from native EPIG dimensions after ISDN (2.57+-0.52 versus 2.56+-0.39 mm), suggesting maximal dilation. However, vasodilation with ISDN was observed in a subgroup of patients at this time. These responder patients (n=51) had a smaller basal diameter (2.47+-0.49 versus 2.67+-0.54 mm, P<.05) and a smaller runoff (P<.001) than nonresponder patients.Conclusions EPIG grafts have a good early patency rate.The mid-term patency rate remains high and seems to depend, at least partially, on flow through the native coronary artery. EPIGs initially increase their lumen size, probably to meet the increased blood flow due to myocardial requirements. Over time, EPIG diameters decrease mainly as a result of a higher basal vasomotor tone. Long-term angiographic follow-up (eg, 5 to 10 years) is needed to assess late patency rate and the rela tion with these early findings and will define the place of this new coronary bypass conduit. (Circulation. 1994;90(part 2):II-148-II-154.)

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Background The gastroepiploic artery is increasingly used as an alternative arterial coronary bypass conduit.In vitro studies have reported differences in vasoreactivity among various types of coronary graft conduits, susceptible to influencing the adaptation of myocardial blood flow and long-term patency rate.Methods and Results To evaluate in vivo the vasoreactivity of gastroepiploic artery grafts implanted long-term, nine angiographically smooth grafts implanted to the distal right or to the left circumflex coronary artery were studied with quantitative angiography 6 to 36 months after surgery. Angiograms were obtained on 35mm cinefilms in basal conditions, after injection of methylergometrine (0.4 mg IV), and after intragraft injection of 1 mg isosorbide dinitrate. In basal conditions, there was no difference in luminal diameter between gastroepiploic and coronary arteries (1.64+-0.32 versus 1.51+-0.31 mm; P=NS). After methylergometrine, a constriction was observed in all gastroepiploic artery grafts (-14+-6% of basal diameter) and in all but one grafted coronary artery (-6+-5%). After isosorbide dinitrate, a dilation was consistently observed in all gastroepiploic artery grafts (+26+-9%) and grafted coronary arteries (+14+-7% of basal). Changes in lumen diameter in response to these constrictor and dilator stimuli, either expressed in absolute values or in percentage of control were significantly greater (P<.001) in gastroepiploic artery grafts than in grafted coronary arteries.Conclusions Gastroepiploic artery grafts implanted long-term are more reactive than grafted coronary arteries to ergometrine and nitrates. This response differs from that previously reported of internal mammary artery grafts to the same pharmacological vasoactive stimuli. This suggests that the concept of a more efficient endothelium-dependent control of vasomotor tone contributing to better long-term functional results of internal mammary artery grafts cannot be directly extrapolated to gastroepiploic artery grafts. (Circulation. 1994;90(part 2):II-155-II-159.)

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID

摘要:

Background Poor patency rates have limited the success of biological vascular grafts in the coronary artery position.Recently, two bovine internal mammary arterial grafts have been developed for possible use as coronary artery bypass graft (CABG) conduits: (1) Denaflex grafts (Baxter Healthcare Co, 3-mm ID) treated with polyepoxy compounds and with heparin ionically bound to the luminal surface and (2) Bioflow grafts (Bio-Vascular, Inc, 3-mm ID) treated with dialdehyde starch.Methods and Results Thirty dogs underwent CABG with either a Denaflex (n=20) or Bioflow (n=10) graft to the left circumflex coronary artery (LCx).The left main coronary artery (n=12) or proximal LCx (n=18) was then ligated. Six-month patency (Kaplan-Meier) for Denaflex grafts was 44+-13% (+-SEM), compared with 12+-11% for Bioflow grafts, but this difference did not reach statistical significance (P=.56). Among grafts open at 14 days, however, there were no occlusions among six Denaflex grafts versus five occlusions among seven Bioflow grafts. At 6 months, all six surviving Denaflex grafts appeared normal, while the only remaining patent Bioflow graft was angiographically dilated and had diffuse luminal irregularities. At 1 year, three Denaflex grafts angiographically had no dilation, stenosis, or luminal irregularities. Macroscopically, all explanted long-term (6 to 12 months) Denaflex grafts had a smooth, clean luminal surface, whereas the only patent Bioflow graft had multifocal thrombi. Microscopically, all Denaflex grafts had minimal degenerative changes, but the Bioflow graft had transmural linear cracks and medial deterioration.6- month) patency is possible with small-caliber, low-flow biological grafts in the canine coronary position, although both types of grafts are prone to early occlusion. If these early failures are excluded, the Denaflex graft appears to be associated with better long-term patency and an absence of degenerative changes. (Circulation. 1994;90(part 2):II-160-II-166.)

ISSN:0009-7322    

出版商:OVID    

年代:1994

数据来源: OVID