Biomedical subjects

S E Fremes

Publications and source records attributed to S E Fremes.

At least 19 recordsLinked to original sources

PubMed2004

The role of N-acetylcysteine in preventing radiographic contrast-induced nephropathy.

INTRODUCTION: There have been many small randomized controlled trials evaluating the effectiveness of N-acetylcysteine (NAC) in preventing radiographic contrast-induced nephropathy. Most studies have suggested a beneficial NAC effect. This meta-analysis describes the effect of NAC in the prevention of radiographic contrast-induced nephropathy in the aggregated trial data. METHODS: A search using MEDLINE from 1966 to December 2003 identified all randomized control trials that evaluated NAC in those patients at risk of acute renal failure (ARF) following either angiographic or CT scan contrast exposure. All studies included in the review employed the use of either low-osmolar (n = 9 trials) or iso-osmolar (n = 2 trials) contrast agents. The outcome of interest was ARF as defined by a rise in serum creatinine (Cr > or = 0.5 mg/dl rise or > 25% increase from baseline) after exposure to contrast. The data were aggregated by the methods of Mantel and Haenszel. RESULTS: The overall summary odds ratio estimate of 0.46 (95% confidence interval 0.32 - 0.66) suggests a strong protective effect of NAC in preventing radiographic-induced nephropathy. CONCLUSION: In summary, there is good aggregate trial evidence to suggest that patients who have an elevated serum creatinine level at baseline benefit from receiving periprocedure NAC in the prevention of contrast-induced ARF.

Acetylcysteine↗

PubMed2001

The radial artery versus the saphenous vein graft in contemporary CABG: a case-matched study.

BACKGROUND: Although use of the internal thoracic artery has been shown to improve outcomes after coronary artery bypass grafting, the same cannot be said of alternative arterial conduits. To determine the benefit of radial artery (RA) grafting, a case-matched review was undertaken. METHODS: Between March 1994 and March 1999, 2,847 patients underwent isolated coronary artery bypass grafting with a left internal thoracic artery graft, plus saphenous vein grafts (SVGs). Of these patients, 478 also received an RA graft (RA group). The RA patients were matched at a ratio of 1:2 with patients receiving only SVGs and a left internal thoracic artery graft (SVG group; n = 956) using six prognostic risk factors: age, sex, Canadian Cardiovascular Society class, left ventricular grade, number of diseased vessels, and timing of operation. Target vessels were graded according to quality and graftability and were similar between groups. Outcomes were evaluated by univariate and multivariate analyses. RESULTS: There was a significantly higher prevalence of diabetes, hypertension, and peripheral vascular disease in the RA group (p < 0.05). Although stay in the intensive care unit was shorter in the RA group (RA, 30 +/- 2 hours, and SVG, 37 +/- 2 hours; p = 0.0002), total hospital stay was similar between groups. The incidence of perioperative myocardial infarction was higher in the SVG group (SVG, 31 of 956 or 3.2%, and RA, 6 of 478 or 1.3%; p = 0.02). Multivariate analysis revealed RA grafting to be protective against early mortality and morbidity (odds ratio = 0.58; 95% confidence interval, 0.37 to 0.90; p = 0.015) and late mortality and morbidity including late reintervention (risk ratio = 0.60; 95% confidence interval, 0.37 to 0.93; p = 0.02). Actuarial freedom from events at 36 months postoperatively was greater in the RA group (RA, 95% +/- 2%, and SVG, 86% +/- 4%; p = 0.01). CONCLUSIONS: Despite a higher prevalence of preoperative comorbidity, patients in the RA group demonstrated improved outcomes after coronary artery bypass grafting. The RA is a viable and beneficial conduit for this operation.

Case-Control Studies↗

PubMed2001

Management of patients with concomitant coronary and carotid vascular disease.

Stroke is a major complication of coronary artery bypass graft (CABG) surgery. Carotid stenosis is an important cause of stroke in certain CABG patients. Randomized trials have revealed that carotid endarterectomy (CEA) is clearly indicated in non-CABG patients with symptomatic severe carotid stenosis. CEA is also indicated in patients with symptomatic moderate stenosis and asymptomatic severe stenosis if the predicted incidence of perioperative morbidity and mortality is low. Therapeutic options for patients with concomitant coronary and carotid disease include CABG alone, CABG plus CEA, and CABG plus carotid stenting. In this article we discuss each of these management techniques in detail, and make recommendations regarding the preferred approach in specific patient populations.

Angioplasty, Balloon, Coronary↗

PubMed2000

Late results of the Warm Heart Trial: the influence of nonfatal cardiac events on late survival.

BACKGROUND: The Warm Heart Trial randomized 1732 CABG patients to receive warm or cold blood cardioplegia. In the warm cardioplegia patients, nonfatal perioperative cardiac events were significantly decreased and the mortality rate was nonsignificantly decreased (1. 4% versus 2.5%, P:=0.12). The purpose of the present study was to evaluate the late results of these trial patients. METHODS AND RESULTS: Randomization was stratified according to surgeon and urgency of the operation. Seven hundred sixty-two patients recruited from 1 of the centers were followed through the hospital clinic for late events. Late survival (including perioperative deaths) at 72 months was nonsignificantly greater in the warm cardioplegia patients (94.5+/-1.7%, mean+/-SEM) than in the cold cardioplegia patients (90.9+/-2.6%). Independent predictors of mortality by Cox proportional hazards model were redo CABG, diabetes mellitus, renal insufficiency, and increasing age. The influence of nonfatal perioperative events (perioperative myocardial infarction according to computerized ECG readings or low output syndrome as determined by an outcome committee) on late survival was also analyzed. Late survival at 84 months was significantly reduced in the group who experienced nonfatal perioperative outcomes (94.5+/-1.7% versus 84. 9+/-4.5%, P:<0.001) and remained a significant predictor after adjustment for other important variables (risk ratio 6.4, 95% CI 1. 87 to 8.73, P:<0.0001). CONCLUSIONS: Effective myocardial protection through either cold or warm blood cardioplegia is essential, because late survival is significantly reduced in patients with nonfatal perioperative cardiac outcomes.

Cardioplegic Solutions↗

PubMed2000

Trends in coronary artery bypass surgery results: a recent, 9-year study.

BACKGROUND: The demographics of patients undergoing coronary artery bypass grafting (CABG) have changed over time and may contribute to differing operative mortality and the combination of mortality and morbidity (M + M). In this study, the trends in results are analyzed and causes are suggested. METHODS: Prospectively collected data concerning 4,839 CABG operations was divided into three time cohorts (1990 to 1992, 1993 to 1995, 1996 to 1998) and analyzed by univariate and multivariate techniques. RESULTS: Mean age and female gender frequency increased in the later time cohorts (60.7 +/- 9.0 to 63.4 +/- 9.9 years and 16.5% to 21.4%, respectively). The following comorbidities were more prevalent in the later time cohorts: diabetes (26.7% versus 18.6%), renal failure (8.5% versus 2.2%), peripheral vascular disease (20.7% versus 11.0%), previous cerebrovascular accident (6.7% versus 5.0%), urgent procedures (41.5% versus 26.9%), unstable angina (47.8% versus 31.7%), urgent CABG following myocardial infarction (17.1% versus 7.3%), previous percutaneous transluminal coronary angioplasty (8.0% versus 4.5%), ejection fraction less than 35% (20.5% versus 10.4%), (all p < 0.05). Procedurally, increased utilization of the left internal mammary artery, multiple arterial conduits, and warm blood cardioplegia occurred in the later cohorts (91.2%, 22.2%, and 80.4% versus 78.7%, 3.4%, and 38.0%, respectively). The mortality rate was 2.0% and the M + M rate was 15.6% in all 4,839 patients. The mortality and M + M for the three cohorts were 1.6%, 2.0%, and 2.3% and 18.4%, 17.2% and 12.5%, respectively. The risk-adjusted mortality and M + M decreased from 2.4% and 15.9%, respectively, in 1990 to 1992 to 1.8% and 8.4% in 1996 to 1998 (p < 0.001). The difference in adjusted event rates was minimized when the surgical factors were entered into the model. CONCLUSIONS: Over time, there has been a trend toward operating on older patients with more comorbidities. Though hospital mortality has been stable, risk-adjusted M + M has been in a constant decline. This decline was associated with an increased use of left internal mammary artery grafts, multiple arterial conduits, and warm blood cardioplegia during the later years of the study.

Aged↗

PubMed2000

The influence of gender on the outcome of coronary artery bypass surgery.

BACKGROUND: To assess the impact of gender as an independent risk factor for early and late morbidity and mortality following coronary artery bypass surgery. METHODS: Perioperative and long-term data on all 4,823 patients undergoing isolated coronary bypass operations from November 1989 to July 1998 were analyzed. Of these patients, 932 (19.3%) were females. RESULTS: During the years 1989 to 1998 there was a progressive increase in the percentage of women undergoing coronary artery bypass surgery. The following preoperative risk factors were more prevalent among women than men: age above 70, angina class 3 or 4, urgent operation, preoperative intraaortic balloon pump usage, congestive heart failure, previous percutaneous transluminal coronary angioplasty, diabetes, hypertension, and peripheral vascular disease (all p < 0.05). Men were more likely to have an ejection fraction less than 35%, three-vessel disease, repeat operations, and a recent history of smoking. Women had a statistically significant smaller mean body surface area than men (1.72+/-0.18 versus 1.96%+/-0.26% m2). On average, women had fewer bypass grafts constructed than men (2.9%+/-0.8% versus 3.2%+/-0.9%) and were less likely to have internal mammary artery grafting (76.2% versus 86.1%), multiple arterial conduits (10.1% versus 19.8%), or coronary endarterectomy performed (4.9% versus 8.6%). The early mortality rate in women was 2.7% versus 1.8% in men (p = 0.09). Women were more prone to perioperative myocardial infarction (4.5% versus 3.1% p < 0.05). After adjustment for other risk variables, female gender was not an independent predictor of early mortality but was a weak independent predictor for the prespecified composite endpoint of death, perioperative myocardial infarction, intraaortic balloon counterpulsation pump insertion, or stroke (8.55 versus 5.9%; odds ratio, 1.30; 95% confidence interval, 0.99 to 1.68; p = 0.05) Recurrent angina class 3 or 4 was more frequent in female patients (15.2%+/-4.0% versus 8.5%+/-2.0% at 60 months, p = 0.001) but not repeat revascularization procedures (percutaneous transluminal coronary angioplasty, redo) (0.6%+/-0.3% versus 4.1%+/-0.8% at 60 months). Actuarial survival at 60 months was greater in women then men (93.1%+/-1.7% versus 90.0%+/-1.0%), and after adjustment for other risk variables, female gender was protective for late survival (risk ratio, 0.40; 95% confidence interval, 0.16-0.74; p < 0.005). CONCLUSIONS: Perioperative complications were increased and recurrent angina more frequent in women. Despite this, late survival was increased in women compared with men after adjustment for other risk variables

Age Factors↗

PubMed2000

Aprotinin and tranexamic acid for high transfusion risk cardiac surgery.

BACKGROUND: Studies have shown that aprotinin and tranexamic acid can reduce postoperative blood loss after cardiac operation. However, which drug is more efficacious in a higher risk surgical group of patients, has yet to be defined in a randomized study. METHODS: With informed consent, 80 patients undergoing elective high transfusion risk cardiac procedures (repeat sternotomy, multiple valve, combined procedures, or aortic arch operation) were randomized in a double-blind fashion, to receive either high dose aprotinin or tranexamic acid. Patient and operative characteristics, chest tube drainage and transfusion requirements were recorded. RESULTS: There was no significant difference between the 2 treatment groups with respect to age, cardiopulmonary bypass time, complications (myocardial infarction, stroke, death), chest tube drainage (6, 12, or 24 hours), blood transfusions up to 24 hours postoperatively, total allogeneic blood transfusions for entire hospital stay, or induction/postoperative hemoglobin levels. However, multiple regression analysis revealed a positive relationship between cardiopulmonary bypass time and 24 hour blood loss in the tranexamic acid group (p = 0.001), unlike the aprotinin group where 24 hour blood loss is independent of cardiopulmonary bypass time (p = 0.423). CONCLUSIONS: Overall, there was no significant difference in blood loss, or transfusion requirements, when patients received either aprotinin or tranexamic acid for high transfusion risk cardiac operation. Aprotinin, when given as an infusion in a high-dose regimen, was able to negate the usual positive effect of cardiopulmonary bypass time on chest tube blood loss.

Antifibrinolytic Agents↗

PubMed2000

Multicenter radial artery patency study (RAPS). Study design.

The use of an internal thoracic artery rather than a saphenous vein graft for left anterior descending coronary artery bypass is associated with improved long-term outcome. Hence, expanded use of arterial conduits for other coronary targets has been advocated. The radial artery possesses a number of anatomic features that are technically advantageous compared with other arterial conduits. This study will determine the relative patency of the radial artery compared to the saphenous vein for right and circumflex coronary bypass. Patients with graftable multivessel coronary disease and an estimated left ventricular ejection fraction >/= 35% undergoing nonemergent primary isolated coronary bypass surgery are eligible. The right and circumflex vessels must have high-grade lesions (>/= 70% diameter stenosis), with target segments of reasonable quality >/= 1.5 mm in diameter. Patients serve as their own controls. The radial artery is randomly allocated to bypass the right or circumflex territory and a saphenous vein is used for the nonradial site. An internal thoracic artery is used for the left anterior descending coronary artery in all cases. Randomization is stratified by center. The primary study endpoint is graft patency as determined by angiography, 8-12 months postoperatively. The relative patency of the radial artery compared with the saphenous vein will be determined using McNemar's test. A sample size of 464 patients will provide 80% power for a two-tailed test (alpha = 0.05) for a 40% relative reduction in the rate of distal anastomotic occlusion from 12% in the saphenous vein to 7.2% in the radial arteries assuming a 20% within-patient correlation. A single interim analysis will be performed following completion of 232 angiograms. To allow for lack of follow-up angiography in up to 20% of enrolled patients, we plan to randomize a total of 560 patients. It is also our intention to assess the long-term patency (5-10 years) of radial artery relative to saphenous vein grafts in follow-up studies. Three hundred patients were recruited from 12 Canadian, university-affiliated sites from November 1996 until February 1999, of which 128 patients have undergone follow-up angiography. Approximately 80% of those who have been followed for more than 1 year have undergone follow-up angiography. This trial will determine the 8-12 month patency of the radial artery relative to the saphenous vein for non-left anterior descending coronary bypass using a novel study design which helps control for potential bias from individual patient and vessel factors. Positive results would support the use of the radial artery in particular, and multiple arterial grafts in general.

Aged↗

PubMed1999

Coronary bypass and carotid endarterectomy: does a combined approach increase risk? A metaanalysis.

BACKGROUND: Patients with concomitant carotid and coronary artery disease present a surgical dilemma. We compared the stroke and mortality rates for combined coronary artery bypass grafting and carotid endarterectomy in which both procedures were performed under a single anesthetic, versus a staged approach, in which coronary artery bypass grafting and carotid endarterectomy were performed separately. METHODS: A computerized MEDLINE search supplemented with a manual bibliographic review was performed for all peer-reviewed English language publications that contained both combined and staged coronary artery bypass grafting/carotid endarterectomy patient cohorts. Outcomes of interest were stroke, death, and stroke or death; aggregation of outcome rates was performed with the Mantel-Haenszel method. RESULTS: Sixteen studies were identified with a total of 844 combined patients and 920 staged patients. None of the studies was completely randomized. The combined surgical group had a higher prevalence of unstable angina; the two groups had a similar prevalence of symptomatic carotid disease and severe carotid stenosis. Meta-analysis revealed a significantly increased risk of the composite end point, stroke or death, for patients undergoing combined procedures (relative risk 1.49; 95% confidence interval 1.03-2.15; p = 0.034). There was also a trend toward increased risk during combined procedures for the end points of stroke (relative risk 1.50; 95% confidence interval 0.97-2.32; p = 0.068) and death (relative risk 1.55; 95% confidence interval 0.94-2.53; p = 0.084) considered separately. The crude event rates for stroke were 6.0% versus 3.2% for combined versus staged procedure, 4.7% versus 2.9% for death, and 9.5% versus 5.7% for stroke or death. Two of the 16 individual studies showed a statistically significant increase in the risk of stroke or death for combined procedure (p < 0.05). CONCLUSIONS: Combined coronary artery bypass grafting and carotid endarterectomy may be associated with a higher risk of stroke or death than staged procedures. A randomized trial needs to be performed to determine the optimal management of patients with concomitant carotid and coronary artery disease.

Cerebrovascular Disorders↗

PubMed1999

A novel comparison of stentless versus stented valves in the small aortic root.

BACKGROUND: Previous studies have compared prosthetic valves on the basis of industry-labeled valve sizes. Unfortunately, the relationship between the labeled size and the true measured external or internal diameter differs between valve manufacturers. Therefore hemodynamic comparisons between prosthetic valves are inaccurate if based solely on industry-labeled valve sizes. METHODS: We have previously demonstrated that the internal diameter of a 21-mm Carpentier-Edwards pericardial stented valve is similar to that of a 25-mm Toronto stentless porcine valve. Therefore we chose to compare postoperative hemodynamics in patients who received 19-, 21-, or 23-mm Carpentier-Edwards pericardial stented valves (inner diameter 18-22 mm, n = 69) with those in patients who received 23- or 25-mm stentless porcine valves (internal diameter 19-21 mm, n = 41). RESULTS: Patients in the Carpentier-Edwards group were more likely to be elderly and more likely to require concomitant revascularization. Operative mortality was lower in the stentless porcine valve group (0% vs 9%, P =.06). Hospital stay and ventilation requirements were shorter in the stentless porcine valve group. Postoperative hemodynamics were similar in the two groups. CONCLUSIONS: These data provide evidence that stentless and stented valves have similar hemodynamic profiles in the small aortic root when matched on true measured internal diameters. The clinical benefit of the stentless porcine valve may be due to patient selection or the lack of a rigid stent in the small aortic root, but it is not due to hemodynamic superiority over stented aortic valves of similar sizes.

Aged↗

PubMed1998

Multiple arterial grafts. Radial versus right internal thoracic arteries.

BACKGROUND: Left internal thoracic artery (LITA) grafts to the left anterior descending coronary artery (LAD) during coronary bypass surgery (CABG) have greater patency rates than saphenous vein grafts and reduce long-term cardiac morbidity and mortality rates. The benefits of multiple versus single arterial grafts and the role of different arterial conduits with respect to short- and medium-term outcome remains controversial. The purpose of this study was to compare the perioperative and intermediate-term results of: (1) patients receiving 2 arterial grafts versus 1 arterial graft and (2) patients receiving a right internal thoracic artery (RITA) versus a radial artery (RA) as the second arterial graft. METHODS AND RESULTS: Retrospective analysis of prospectively gathered data on consecutive patients undergoing isolated CABG at our institution between 1989 and 1996 was conducted. The first section of the study compared outcomes for 1 arterial graft (LITA to LAD, n = 2333) versus 2 arterial grafts (LITA + RA or LITA + RITA, n = 378). The second section of the study compared outcomes for the RITA (n = 132) versus the RA (n = 171) as second arterial grafts since 1992, when the radial series was initiated. Part I: By multivariable stepwise logistic regression, the use of 1 arterial graft was associated with an increased incidence of perioperative cardiac morbidity and mortality (odds ratio 2.2, 95% confidence interval 1.4 to 3.3), with the use of our current patient selection criteria. Double-arterial graft patients had a nonsignificant trend toward increased intermediate-term actuarial survival (P = 0.12) and cardiac event-free survival (P = 0.09). Part II: Comparison of preoperative demographics revealed a higher incidence of diabetes (27% vs 11%, P < 0.001), peripheral vascular disease (16% vs 8%, P = 0.03), and elderly age (13% vs 2%, P = 0.001) in patients receiving an RA versus those receiving a RITA as the second arterial graft. Perioperative outcome analysis revealed a decreased intensive care unit stay in the RA versus RITA group (median 30.4 vs 36.2 hours, respectively, P = 0.005) but no significant difference in hospital length of stay. There was no significant difference in perioperative mortality or cardiac morbidity rates. RITA patients had a higher incidence of sternal wound infection (5.3% vs 0.6%, P = 0.01), however, and tended to have increased blood product transfusion rates (51% vs 40%, P = 0.06). CONCLUSIONS: The use of 2 arterial grafts is safe, with a reduction in perioperative cardiac morbidity or mortality rates compared with 1 arterial graft after adjustment for other risk variables. When comparing RITA to RA as second arterial grafts, patients receiving an RA have a lower incidence of sternal wound infection and decreased transfusion requirements, with no difference in perioperative or intermediate-term cardiac morbidity or mortality rates.

Aged↗

PubMed1998

Phase 2 studies of adenosine cardioplegia.

BACKGROUND: Laboratory evidence supports the use of adenosine-supplemented cardioplegia. An initial phase 1 dose-ranging clinical evaluation demonstrated that an adenosine concentration of 15 mumol/L could be safely administered with warm blood cardioplegia and suggested that phase 2 studies were warranted. METHODS AND RESULTS: Two separate double-blind, randomized, placebo-controlled trials were performed in patients undergoing primary, isolated, nonemergent coronary artery bypass graft surgery. Patients were randomized to receive adenosine 15 mumol/L versus placebo in the first study (n = 200) and adenosine 50 or 100 mumol/L versus placebo in the second study (n = 128). Adenosine was infused with both initial and final doses of warm antegrade blood cardioplegia. The data from the 2 trials were combined using the methods of Mantel and Haenszel, and the results of the meta-analysis are presented as the relative risk with their associated 95% confidence intervals (CI). The different study groups were comparable with respect to all preoperative clinical characteristics, angiographic findings, and intraoperative variables. In both trials 1 and 2, no differences were found between groups in the incidence of the individual primary or secondary outcomes. Similarly, when both studies were combined, there was no significant evidence of any consistent treatment benefit (primary: death: relative risk [RR] = 1.02, 95% CI = 0.06, 16.6; myocardial infarction by CK-MB: RR = 0.84, CI = 0.54, 1.31; low output syndrome: RR = 1.38, CI = 0.29, 6.42; any of the above: RR = 0.98, CI = 0.78, 1.25; secondary: Q-wave myocardial infarction: RR = 1.30, CI = 0.41, 4.13; myocardial infarction by troponin T: RR = 0.7, CI = 0.40, 1.21; inotrope requirement: RR = 0.9, CI = 0.46, 1.79; intra-aortic balloon pump requirement: RR = 0.6, CI = 0.07, 4.81; P > 0.20). CONCLUSIONS: Despite promising experimental data, adenosine supplementation of warm blood cardioplegia did not demonstrate any statistically significant benefit in patients undergoing elective coronary artery bypass graft surgery. Although sample sizes were relatively small, based on our interim analyses, it is unlikely that increased patient enrollment would reveal any substantive clinical differences between groups.

Adenosine↗

PubMed1998

Inaccurate and misleading valve sizing: a proposed standard for valve size nomenclature.

BACKGROUND: The sizes with which manufacturers label valves are nonuniform and haphazard. This has led to confusion and inappropriate comparisons of hemodynamics between valves with the same labeled size. Hemodynamic performance of valves is primarily determined by the internal diameter (ID) of their orifice. METHODS: The purpose of this study was to determine the ID and external diameter of aortic valves used at our institution and compare the measurements to manufacturers' labeled sizes. We also evaluated valve size (ID, manufacturers' labeled size) in 527 patients undergoing isolated aortic valve replacement between 1990 and 1996. RESULTS: We demonstrated that no two manufacturers' tissue or mechanical valves have the same ID or external diameter for a given labeled size. The labeled size of tissue valves was 1 to 4 mm larger than the measured ID. The labeled size of mechanical valves was 3 to 5 mm larger than the measured ID. The St. Jude HP mechanical valve has a greater ID than all other mechanical valves for each labeled size. Among 403 patients operated on for predominant aortic stenosis, those patients receiving the Toronto Stented Porcine Valve (n = 98) had a larger mean ID (22.3+/-1.9 mm) than 204 patients receiving stented tissue valves (ID = 20.9+/-1.9 mm) and the 101 patients receiving mechanical valves (ID = 19.3+/-1.9 mm, p < 0.0001). However, when the manufacturers' labeled size was used as a measure of the size, the results were greatly exaggerated in favor of the Toronto Stented Porcine Valve (ID = 26.3+/-1.9 mm) compared with stented tissue valves (ID = 23.1+/-2.1) or mechanical valves (ID = 23.6+/-1.9) (p < 0.0001). CONCLUSIONS: Manufacturers' labeling of valves is nonuniform and may lead to erroneous comparisons and conclusions of hemodynamic differences between valves. We therefore recommend a standardized nomenclature for the size of all valves based on the ID measurement.

Aortic Valve↗

PubMed1998

Coronary bypass with arterial conduits.

To assess the efficacy of arterial revascularization 368 patients were studied who underwent myocardial revascularization with two or more arterial conduits (group M) and compared with 2092 patients in whom a single internal mammary artery +/- veins (group S), and to a third group in which only saphenous vein conduits (group V, n = 602) were used. Group M patients were younger (aged 54.0(9.5) years; 4.1% aged > 70 years) than either group V (67.6(8.9) years, 40.7% > 70 years, P < 0.0001) or group S patients (62.0(8.5) years, 15.7% > 70 years, P < 0.0001). Furthermore, this cohort group had the lowest percentage of females (8.4%), of urgent cases (21.7%), of preoperative myocardial infarction (6.0%), and of redo surgery (0.8%). In contrast, patients who received only saphenous vein conduits had the highest proportion of female patients (29.2%), of urgent cases (47.4%), of preoperative myocardial infarction (16.5%), and of redo surgery (5.5%). By multivariate logistic regression analysis (odds ratio in parentheses), redo surgery (6.06, P = 0.0001), preoperative intra-aortic balloon pump assist (6.11, P = 0.0001), diabetes (1.97, P = 0.03), urgent surgery (1.80, P = 0.05), and advanced age (2.14, P = 0.01) were all predictors of operative mortality. In contrast, while choice of conduit appeared to influence outcome by univariate analysis (4.2% mortality in group V, P < 0.001), it was not found to be a predictor of either mortality or morbidity by regression analysis. The present results indicate that, in carefully selected patients, despite increased technical demands with longer periods of aortic occlusion and longer pump times, multi-arterial grafting (compared with conventional revascularization) is a safe and efficacious procedure. Whether or not this approach to revascularization will increase long-term survival and freedom from reoperation will require further study.

Aged↗

PubMed1998

Early results using an ePTFE membrane for pericardial closure following coronary bypass grafting.

A prospective randomized trial was conducted to evaluate the early efficacy and safety of the Gortex surgical membrane. Three hundred two patients (265 males, 37 females) undergoing isolated coronary bypass surgery were randomized to receive a Gortex membrane (GM = 138) or have the pericardium left open (complication [C] = 164). The groups did not differ in age, gender, urgency of procedure, length of procedure, or use of arterial grafts. Two deaths occurred in each group giving an overall mortality of 1.3%. Fifty-three (17%) patients experienced some complication (C = 34, 21%), GM = 19 (14%). Although the combined complication rate was higher in the control group, this was not statistically significant (chi2 = 2.51, p = 0.11). Postoperative ischemic events (C = 8, GM = 4) observed between the groups were not significant (chi2 = 0.05, p = 0.8), and no statistically significant difference was observed between the incidences of infections (C = 7, GM = 5) or mediastinal complications (C = 3, GM = 3). The Gortex surgical membrane can be used safely without increasing the risk of infection or mediastinal complications. The incidence of recurrent myocardial ischemia, a possible indicator of graft compression, was not higher following membrane implantation. Efficacy at injury prevention will need to be determined by a longitudinal follow-up study presently underway.

Adult↗

PubMed1997

Coronary artery bypass grafting in patients with non-dialysis-dependent renal insufficiency.

BACKGROUND: Preoperative renal failure increases the morbidity and mortality of coronary artery bypass graft (CABG) surgery. The results of CABG in patients with non-dialysis-dependent, mild renal insufficiency are unknown. METHODS: From a population of 2978 consecutive patients undergoing isolated CABG from 1990 to 1996, 38 patients with preoperative renal insufficiency (Renal group; serum creatinine >150 micromol/L) were identified and matched on six prognostic variables to a cohort of 152 control patients (Control group). Two patients with preoperative dialysis-dependent renal failure were excluded from analysis. RESULTS: Compared to the overall population, the Renal group were more likely to be over age 70, diabetic, hypertensive, and suffer from peripheral vascular disease and left ventricular dysfunction. Compared to the Control group, the Renal group were more likely to require perioperative blood transfusions (P<.001) and had a greater requirement for postoperative dialysis (P<.01). The Renal group had longer ventilation times, intensive care unit stay, and postoperative hospital stay. Mild renal insufficiency was found to be an independent predictor of postoperative low output syndrome (odds ratio=3.6). CONCLUSIONS: Mild renal insufficiency, even in the absence of dialysis, increases the risk of blood transfusion, low output syndrome and prolonged the length of intensive care unit and postoperative stay for patients undergoing CABG.

Aged↗

PubMed1997

In vivo validation of MR pulse pressure measurement in an aortic flow model: preliminary results.

MR imaging experiments were conducted to investigate the feasibility of estimating vascular pulse pressure waveforms from measurements of blood flow rates and vessel cross-sectional area. Blood flow waveforms were measured in the aorta's of three 25-30-kg pigs at multiple imaging sections using phase-contrast velocity imaging. Estimates of pulse pressure were derived from these data by evaluating a model characterizing the relationship between pressure, flow, and the cross-sectional area of a vessel segment. Comparisons between the MR-derived estimates of pressure and those obtained from a micromanometer pressure catheter indicate that accurate measurements (mean error +/- SD = 8.2 +/- 3.4, n = 6) can be obtained using conventional velocity imaging techniques. Optimization of the method will require the application of rapid imaging techniques and the development of strategies for obtaining a more localized measurement. With these improvements, our results suggest that MR-based measurement of pulse pressure and related elastic parameters is feasible.

Animals↗

PubMed1997

Effects of butanedione monoxime and temperature on prolonged cardiac storage.

BACKGROUND: The optimal temperature for cardiac allograft storage remains controversial. We conjectured that supplementation of the potent cardioprotective agent 2,3-butanedione monoxime with calcium may improve allograft storage and make the precise storage temperature less critical. METHODS: Hearts were harvested from Sprague-Dawley rats (250 to 350 g), mounted on a Langendorff apparatus, and instrumented with an intraventricular balloon. Hearts were flushed and stored with either unmodified University of Wisconsin solution (UWS) or UWS supplemented with 10 mmol/L of 2,3-butanedione monoxime and calcium 0.1 mmol/L (BDM). Hearts were then subjected to 12 hours of storage at one of five temperatures (0 degree, 4 degrees, 8 degrees, 12 degrees, or 16 degrees C) in a complete 2 x 5 factorial design (n = 6/group). Data are reported either as a percentage of the prestorage results or as an absolute value (mean +/- standard deviation). RESULTS: Recovery of developed pressure (p < 0.0001), coronary flow (p < 0.0001), and diastolic volume (p < 0.001) were significantly enhanced, whereas creatine kinase (p < 0.0001) and lactate dehydrogenase release (p < 0.0001) were reduced in the BDM versus the UWS groups. In both the BDM and UWS storage groups, recovery was better at temperatures of 8 degrees C or less than at 12 degrees C or more. The single preferred temperature was 4 degrees C, significantly better than 0 degree C with unmodified UWS, while similar to 0 degree and 8 degrees C with BDM. Adenine nucleotide values were decreased equally in the BDM and UWS hearts, but preservation was enhanced at 0 degree C compared with all warmer temperatures. CONCLUSIONS: We conclude that 4 degrees C is the preferred temperature for prolonged cardiac storage with UWS and that the inclusion of 2,3-butanedione monoxime with calcium 0.1 mmol/L markedly enhances recovery for storage temperatures of 8 degrees C or less.

Adenosine↗