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Objectives: It has been hypothesized that the survival benefit of coronary artery bypass (CABG) compared with percutaneous interventions (PCI) may be associated with the reduction in spontaneous myocardial infarction (SMI) achieved by surgery. This, however, has not been formally investigated. The present meta-analysis aims to evaluate the association between the difference in SMI and in survival in PCI versus CABG randomized controlled trials (RCTs)., Methods: A systematic search was performed to identify all RCTs comparing PCI with CABG for the treatment of coronary artery disease and reporting SMI outcomes. Generic inverse variance method was used to pool outcomes as natural logarithms of the incident rate ratios across studies. Subgroup analysis and interaction test were used to compare the difference of the primary outcome among trials that did and did not report a significant reduction in SMI- in the patients treated by CABG. Primary outcome was all-cause mortality; secondary outcome was SMI., Results: Twenty RCTs were included in the meta-analysis. A statistically significant difference in SMI in favor of CABG was found in 7 of the included trials (35%). Overall, PCI was associated with significantly greater all-cause mortality (incident rate ratio, 1.13; 95% confidence interval, 1.01-1.28). At subgroup analysis, a significant difference in survival in favor of CABG was seen only in trials that reported a significant reduction in SMI in the surgical arm (P for interaction 0.02)., Conclusions: In the published PCI versus CABG trials, the reduction in all-cause mortality in the surgical arm is associated with the protective effect of CABG against SMI., (Copyright © 2021 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Background: We describe variables and outcomes associated with peri-operative mechanical circulatory support (MCS) utilization among patients enrolled in the Levosimendan in patients with Left Ventricular Systolic Dysfunction Undergoing Cardiac Surgery Requiring Cardiopulmonary Bypass (LEVO-CTS) trial., Methods: In the LEVO-CTS trial, MCS utilization (defined as intra-aortic balloon pump, extracorporeal membrane oxygenation, or surgical ventricular assist device) within 5 days of surgery was examined. The association between MCS use and outcomes including 90-day mortality, 30-day renal-replacement therapy, and hospital and critical stay length of stay were determined., Results: Among the 849 patients from 70 centers randomized to levosimendan or placebo, 85 (10.0%) patients were treated with MCS (71 intra-aortic balloon pump, 7 extracorporeal membrane oxygenation, 7 ventricular assist device); with 89.4% started on post-operative day 0. Inter-institutional use ranged from 0% to 100%. Variables independently associated with MCS utilization included combined coronary artery bypass grafting and valve surgery (adjusted odds ratio [OR] 2.73, 95% confidence interval [CI] 1.70-4.37, P < .001), history of lung disease (OR 1.70, 95% CI 1.06-2.70, P = .029), and history of heart failure (OR 2.44, 95% CI 1.10-5.45, P = .027). Adjusted 90-day mortality (22.4% vs 4.1%, hazard ratio 6.11, 95% CI 3.95-9.44, P < .001) was higher, and median critical care length of stay (8.0 vs 4.0 days, P < .001) was longer in patients managed with MCS., Conclusions: In a randomized controlled trial of high-risk cardiac surgical patients in North America, we observed patient, and surgical variables associated with MCS utilization. MCS use was associated with a higher risk of post-operative mortality., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Objectives: We aimed to evaluate the association between levosimendan treatment and acute kidney injury (AKI) as well as assess the clinical sequelae of AKI in cardiac surgery patients with depressed left ventricular function (ejection fraction <35%)., Methods: Patients in the LEVO-CTS trial undergoing on-pump coronary artery bypass grafting (CABG), valve, or CABG/valve surgery were stratified by occurrence and severity of postoperative AKI using the AKIN classification. The association between levosimendan infusion and AKI was modeled using multivariable regression., Results: Among 854 LEVO-CTS patients, 231 (27.0%) experienced postoperative AKI, including 182 (21.3%) with stage 1, 35 (4.1%) with stage 2, and 14 (1.6%) with stage 3 AKI. The rate of AKI was similar between patients receiving levosimendan or placebo. The odds of 30-day mortality significantly increased by AKI stage compared to those without AKI (stage 1: adjusted odds ratio [aOR] 2.0, 95% confidence interval [CI] 0.8-4.9; stage 2: aOR 9.1, 95% CI 3.2-25.7; stage 3: aOR 12.4, 95% CI 3.0-50.4). No association was observed between levosimendan, AKI stage, and odds of 30-day mortality (interaction P = .69). Factors independently associated with AKI included increasing age, body mass index, diabetes, and increasing baseline systolic blood pressure. Increasing baseline eGFR and aldosterone antagonist use were associated with a lower risk of AKI., Conclusions: Postoperative AKI is common among high-risk patients undergoing cardiac surgery and associated with significantly increased risk of 30-day death or dialysis. Levosimendan was not associated with the risk of AKI., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: The optimal role of radial artery grafts in coronary artery bypass grafting (CABG) remains uncertain. The purpose of this study was to examine angiographic and clinical outcomes following CABG among patients who received a radial artery graft., Methods: Patients in the angiographic cohort of the PREVENT-IV trial were stratified based upon having received a radial artery graft or not during CABG. Baseline characteristics and 1-year angiographic and 5-year clinical outcomes were compared between patients., Results: Of 1,923 patients in the angiographic cohort of PREVENT-IV, 117 received a radial artery graft. These patients had longer surgical procedures (median 253 vs 228 minutes, P < .001) and had a greater number of grafts placed (P < .0001). Radial artery grafts had a graft-level failure rate of 23.0%, which was similar to vein grafts (25.2%) and higher than left internal mammary artery grafts (8.3%). The hazard of the composite clinical outcome of death, myocardial infarction, or repeat revascularization was similar for both cohorts (adjusted hazard ratio 0.896, 95% CI 0.609-1.319, P = .58). Radial graft failure rates were higher when used to bypass moderately stenotic lesions (<75% stenosis, 37% failure) compared with severely stenotic lesions (≥75% stenosis, 15% failure)., Conclusions: Radial artery grafts had early failure rates comparable to saphenous vein and higher than left internal mammary artery grafts. Use of a radial graft was not associated with a different rate of death, myocardial infarction, or postoperative revascularization. Despite the significant potential for residual confounding associated with post hoc observational analyses of clinical trial data, these findings suggest that when clinical circumstances permit, the radial artery is an acceptable alternative to saphenous vein and should be used to bypass severely stenotic target vessels., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objective: In the Levosimendan in Patients with Left Ventricular Systolic Dysfunction Undergoing Cardiac Surgery Requiring Cardiopulmonary Bypass (LEVO-CTS) trial, no differences in clinical outcomes were observed between levosimendan and placebo in a broad population of patients undergoing cardiac surgery. In previous studies, the benefits of levosimendan were most clearly evident in patients undergoing isolated coronary artery bypass grafting (CABG) surgery. In a prespecified analysis of LEVO-CTS, we compared treatment-related outcomes and costs across types of cardiac surgical procedures., Methods: Overall, 563 (66.4%) patients underwent isolated CABG, 97 (11.4%) isolated valve, and 188 (22.2%) combined CABG/valve surgery. Outcomes included the co-primary 4-component composite (30-day mortality, 30-day renal replacement, 5-day myocardial infarction, or 5-day mechanical circulatory support), the 2-component composite (30-day mortality or 5-day mechanical circulatory support), 90-day mortality, low cardiac output syndrome (LCOS), and 30-day medical costs., Results: The 4- and 2-component outcomes were not significantly different with levosimendan and placebo in patients undergoing CABG (15.2% vs 19.3% and 7.8% vs 10.4%), valve (49.0% vs 33.3% and 22.4% vs 2.1%), or combined procedures (39.6% vs 35.9% and 24.0% vs 19.6%). Ninety-day mortality was lower with levosimendan in isolated CABG (2.1% vs 7.9%; hazard ratio [HR], 0.26; 95% confidence interval [CI], 0.11-0.64), but not significantly different in valve (8.3% vs 2.0%; HR, 4.10; 95% CI, 0.46-36.72) or combined procedures (10.4% vs 7.6%; HR, 1.39; 95% CI, 0.53-3.64; interaction P = .011). LCOS (12.0% vs 22.1%; odds ratio, 0.48; 95% CI, 0.30-0.76; interaction P = .118) was significantly lower in levosimendan-treated patients undergoing isolated CABG. Excluding study drug costs, median and mean 30-day costs were $53,707 and $65,852 for levosimendan and $54,636 and $67,122 for placebo, with a 30-day mean difference (levosimendan - placebo) of -$1270 (bootstrap 95% CI, -$8722 to $6165)., Conclusions: Levosimendan was associated with lower 90-day mortality and LCOS in patients undergoing isolated CABG, but not in those undergoing isolated valve or combined CABG/valve procedures., (Copyright © 2019 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Objectives: Prolonged mechanical ventilation after cardiac surgery imposes a significant burden on the patient in terms of morbidity as well as a financial burden on the hospital. We undertook a retrospective analysis of 2 prospectively collected databases developed in tertiary cardiac care centers to derive and validate a risk index predicting prolonged mechanical ventilation after cardiac surgery., Methods: We studied a retrospective cohort of 32,045 patients undergoing cardiac surgery in 2 hospitals in Toronto, Canada. The development cohort consisted of 21,661 patients at Toronto General Hospital. Data Sunnybrook Health Sciences Centre, Toronto, Canada, with 10,384 patients, served as an institutional validation cohort. We operationally characterized prolonged mechanical ventilation as the duration from surgery completion to extubation exceeding 48 hours., Results: Prolonged postoperative mechanical ventilation rates in the development and validation cohort were 6% and 7%, respectively. Multivariable regression in the development cohort showed that the following factors were strong predictors of prolonged mechanical ventilation after cardiac surgery: previous cardiac surgery, lower left ventricular ejection fraction, shock, surgery involving repair of congenital heart disease, and cardiopulmonary bypass time. The intraoperative multivariable model retained good discrimination in the validation cohort, achieving a c statistic of 0.787., Conclusions: Prolonged mechanical ventilation after cardiac surgery can be accurately predicted by readily available pre- and intraoperative information., (Copyright © 2016 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Background: Low cardiac output syndrome is associated with increased mortality and occurs in 3% to 14% of patients undergoing cardiac surgery on cardiopulmonary bypass (CPB). Levosimendan, a novel calcium sensitizer and K ATP channel activator with inotropic, vasodilatory, and cardioprotective properties, has shown significant promise in reducing the incidence of low cardiac output syndrome and related adverse outcomes in patients undergoing cardiac surgery on CPB., Methods: LEVO-CTS is a phase 3 randomized, controlled, multicenter study evaluating the efficacy, safety, and cost-effectiveness of levosimendan in reducing morbidity and mortality in high-risk patients with reduced left ventricular ejection fraction (≤35%) undergoing cardiac surgery on CPB. Patients will be randomly assigned to receive either intravenous levosimendan (0.2 μg kg -1 min -1 for the first hour followed by 0.1 μg/kg for 23hours) or matching placebo initiated within 8hours of surgery. The co-primary end points are (1) the composite of death or renal replacement therapy through day 30 or perioperative myocardial infarction, or mechanical assist device use through day 5 (quad end point tested at α<.01), and (2) the composite of death through postoperative day 30 or mechanical assist device use through day 5 (dual end point tested at α<.04). Safety end points include new atrial fibrillation and death through 90days. In addition, an economic analysis will address the cost-effectiveness of levosimendan compared with placebo in high-risk patients undergoing cardiac surgery on CPB. Approximately 880 patients will be enrolled at approximately 60 sites in the United States and Canada between July 2014 and September 2016, with results anticipated in January 2017., Conclusion: LEVO-CTS, a large randomized multicenter clinical trial, will evaluate the efficacy, safety, and cost-effectiveness of levosimendan in reducing adverse outcomes in high-risk patients undergoing cardiac surgery on CPB., Clinical Trial Registration: ClinicalTrials.gov (NCT02025621)., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Objectives: This study investigates whether the no-touch (NT) vein graft, at a mean time of 16 years, maintains a significantly higher patency rate than conventional (C) vein grafts and still has patency comparable to that of the left internal thoracic artery (LITA)., Methods: A total of 156 patients accepted for coronary artery bypass grafting were randomly allocated to 1 of 3 groups. In the C group, the saphenous vein (SV) was stripped and distended. In the intermediate group, the SV was stripped but not distended. In the NT group, the SV was neither stripped nor distended, but rather harvested with a fat pedicle. This study is an angiographic follow-up of the C and NT groups, at a mean time of 16 years postoperatively., Results: Fifty-four patients were included (C group = 27; NT group = 27). In all, 72 and 75 vein grafts were completed in groups C and NT, respectively. Crude SV graft patency was 64% in the C group versus 83% in the NT group (P = .03), which was similar to the patency of the LITA (88%). The harvesting technique had a major impact on the patency with a hazard ratio for occlusion of 1.83 for the C group (P = .04)., Conclusions: Harvesting the SV with the NT technique conferred, at a mean time of 16 years, a significantly higher patency than the conventional technique that was still comparable to that of the LITA., (Copyright © 2015 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Objectives: The study objective was to identify the predictors of outcomes in a contemporary cohort of patients from the Reduction in cardiovascular Events by acaDesine in patients undergoing CABG (RED-CABG) trial. Despite the increasing risk profile of patients who undergo coronary artery bypass grafting, morbidity and mortality have remained low, and identification of the current predictors of adverse outcomes may permit new treatments to further improve outcomes., Methods: The RED-CABG trial was a multicenter, randomized, double-blind, placebo-controlled study that determined that acadesine did not reduce adverse events in moderately high-risk patients undergoing nonemergency coronary artery bypass grafting. The primary efficacy end point was a composite of all-cause death, nonfatal stroke, or the need for mechanical support for severe left ventricular dysfunction through postoperative day 28. Logistic regression modeling with stepwise variable selection identified which prespecified baseline characteristics were associated with the primary outcome. A second logistic model included intraoperative variables as potential covariates., Results: The 4 independent preoperative risk factors predictive of the composite end point were (1) a history of heart failure (odds ratio, 2.9); (2) increasing age (odds ratio, 1.033 per decade); (3) a history of peripheral vascular disease (odds ratio, 1.6); and (4) receiving aspirin before coronary artery bypass grafting (odds ratio, 0.5), which was protective. The duration of the cardiopulmonary bypass (odds ratio, 1.8) was the only intraoperative variable that contributed to adverse outcomes., Conclusions: Patients who had heart failure and preserved systolic function had a similar high risk of adverse outcomes as those with low ejection fractions, and new approaches may mitigate this risk. Recognition of patients with excessive atherosclerotic burden may permit perioperative interventions to improve their outcomes. The contemporary risks of coronary artery bypass grafting have changed, and their identification may permit new methods to improve outcomes., (Copyright © 2014 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

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.

Although small body size and coronary artery diameter are recognized as major contributors to the increased risk of coronary artery bypass grafting in women, few studies have established the independent influence of body size and gender on outcome. We studied 7025 consecutive patients (5694 men, 1331 women) undergoing isolated coronary artery bypass grafting between 1990 and 1994. Women were older, had higher preoperative prevalences of urgent operation because of unstable angina, diabetes, peripheral vascular disease, hypertension, and single-vessel coronary artery disease (p < 0.0001), and a lower prevalence of left ventricular ejection fraction 40% or less (p < 0.0001). The prevalences of operative mortality (men, 1.8%; women, 3.5%), low-output syndrome (men, 6.6%; women, 14.8%), and myocardial infarction (men, 2.8%; women, 5.5%) were higher in women (p < 0.0001). Patients were divided into quartiles for body surface area, weight, height, and body mass index. For both men and women, there was no difference in operative mortality between the highest and lowest quartiles of body size. Women, however, had a higher prevalence of operative mortality than men in the lower quartiles of body surface area, height, and weight and in the higher quartiles of body mass index. Among men, the prevalence of low-output syndrome increased (p < 0.0001) with decreasing body surface area, weight, and body mass index, suggesting that body size did influence the prevalence of low-output syndrome. However, women had a higher prevalence of low-output syndrome than men in every category and quartile of body size (p < 0.0001). Multivariable analysis identified gender as a significant determinant of operative mortality (odds ratio 1.83, 95% confidence interval 1.27 to 2.64) and low-output syndrome (odds ratio 2.52, 95% confidence interval 2.05 to 3.11). When multivariable adjustments were made for body size and preoperative risk factors, gender remained a predictor of both operative mortality and low-output syndrome. Multivariable assessment of risk for men and women separately identified that urgent operation was a predictor of operative mortality (odds ratio 2.52, 95% confidence interval 1.32 to 5.61) and low-output syndrome (odds ratio 1.57, 95% confidence interval 1.14 to 2.17) in women but not men. In conclusion, the increased risk of coronary artery bypass grafting in women may be explained in part by dramatic differences in preoperative risk factors between men and women. In both men and women, small body size did not increase the risk of operative mortality, but may have contributed to the risk of low-output syndrome.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenosine pretreatment has been shown to be beneficial in several models of ischemia-reperfusion. We wished to evaluate whether adenosine pretreatment is cardioprotective for prolonged cardiac storage and whether the presence of adenosine in the storage media affects the results. Isolated rodent hearts were obtained from Sprague-Dawley rats, mounted on a Langendorff apparatus, instrumented with an intraventricular balloon, and ventricularly paced at 300 beats/min. Four groups of hearts were studied in a 2 x 2 factorial experiment (n = 8 to 12 per group). Hearts were subjected to normal perfusion or to solution supplemented with adenosine 50 mumol/L for 10 minutes followed by adenosine-free perfusion for 10 minutes. Hearts then were stored for 8 hours at 0 degrees C in either University of Wisconsin solution (adenosine 5 mmol/L) or St. Thomas' Hospital II solution (adenosine free). Adenosine pretreatment increased tissue levels of adenosine triphosphate before storage (p = 0.04). Nonfunction was less common after storage (1/19 versus 6/20 hearts, p < 0.05), and diastolic function was better preserved in the adenosine groups in the reperfusion phase (p = 0.01). The beneficial effects of adenosine pretreatment were independent of which storage solution was used. Developed pressure was increased (p < 0.05) and release of creatine kinase and lactate dehydrogenase was reduced (p < 0.0001) in hearts treated with University of Wisconsin solution compared with those treated with St. Thomas' Hospital solution. These studies suggest that adenosine pretreatment improves recovery after prolonged hypothermic storage and that the presence of adenosine in the preservation solution does not alter the results. The experiments provide further evidence that extended myocardial protection is better enhanced with University of Wisconsin solution than with St. Thomas' Hospital II solution.

Although patients with severe ventricular dysfunction have improved long-term survival times after coronary bypass procedures, operative morbidity and mortality rates remain high. This study was designed to identify the contemporary risk factors for isolated coronary artery bypass grafting in this high-risk subgroup. Between January 1982 and December 1990, a total of 12,471 patients underwent isolated coronary artery bypass grafting. The 9445 patients with preoperative ejection fractions greater than 40% had a lower operative mortality rate (2.3%) than that of the 2539 patients with ejection fractions between 20% and 40% (4.8%) and that of the 487 patients with ejection fractions less than 20% (9.8%; p less than 0.001). However, patients with ejection fractions of less than 20% were demographically distinct from those with higher ejection fractions. This group was older, with fewer women, a higher frequency of left main stenosis, and more frequent requirement of urgent operation for unstable angina. The risk factors for operative death also varied with preoperative ejection fraction. The traditionally accepted risk factors--urgency of operation, left main coronary artery stenosis, reoperation, sex, and age--were predictive of risk of operative death for patients with ejection fractions greater than 40%. The risk of operative death for patients with ejection fractions between 20% and 40% was predicted by urgency of operation, reoperation, sex, myocardial protection, and age. The only predictor of risk of operative death for patients with ejection fractions less than 20% was urgency of operation. Patients undergoing isolated coronary artery bypass grafting who have severe ventricular dysfunction are therefore a highly selected, high-risk subgroup of patients who risk depends on the urgency of operation. Strategies to improve the results in these patients should be focused on patient selection, improvement of myocardial protection, and more aggressive preoperative treatment of myocardial ischemia.

Hypothermic storage of cardiac allografts is routinely used for transplantation but is associated with an increased mortality when ischemic times are greater than 4 hours. The ideal storage conditions (solution and temperature) could extend the current limits of cold ischemia. Human endothelial cells and ventricular myocytes were studied to screen various solutions and temperatures for organ preservation. Four solutions (modified Euro-Collins, phosphate-buffered saline, Stanford cardioplegia, and University of Wisconsin) were evaluated. Endothelial cells were evaluated after prolonged hypothermic storage consisting of 0 degree, 4 degrees, and 8 degrees C for 36 hours, and ventricular myocytes were stored at 0 degree and 8 degrees C for 24 hours. Cell viability was determined by morphology (10 dishes per group), and trypan blue exclusion (5 dishes per group) in addition to a cell adhesion assay (endothelial cells 5 dishes per group) and adenine nucleotide analysis with high-performance liquid chromatography techniques (ventricular myocytes 5 dishes per group). Endothelial cell morphology was best preserved by University of Wisconsin solution (p less than 0.001, chi 2) and at 0 degree C (p less than 0.01, chi 2). Endothelial cells stored with University of Wisconsin solution excluded trypan blue better (1.0% +/- 0.5% cells stained, p less than 0.001. Analysis of variance [ANOVA]). Cell adhesion was poorly protected with Stanford cardioplegia (p less than 0.001, ANOVA). Myocyte morphology was preserved best with University of Wisconsin solution at 0 degree C (p less than 0.001, chi 2). According to trypan blue staining, Euro-Collins and University of Wisconsin solutions were superior to Stanford cardioplegia or phosphate-buffered solutions (p less than 0.001, ANOVA). Temperature did not influence the trypan blue results. Adenosine triphosphate was maintained best with University of Wisconsin solution at 0 degree C (p less than 0.01, ANOVA). Myocytes were more sensitive to the effects of prolonged storage compared with endothelial cells by morphologic criteria and trypan blue staining characteristics, irrespective of the shorter preservation times. University of Wisconsin solution was the most effective solution tested. Colder temperatures (0 degree to 4 degrees C) provided better protection than 8 degrees C. Myocytes were more sensitive to prolonged preservation than endothelial cells. Furthermore, the technique used appears helpful as a model of prolonged hypothermic storage and could be expanded to assess other interventions.

A case report of the first single lung transplantation and closure of a patent ductus arteriosus for Eisenmenger's syndrome is presented. The operation was performed on Sept. 28, 1988. The patient was extubated on postoperative day 8, discharged from the intensive care unit on postoperative day 13, and discharged from the hospital on postoperative day 43, free of symptoms and without supplementary oxygen. Subsequent symptoms of dyspnea, presyncope, and fatigue recurred in association with subvalvular right ventricular outflow tract obstruction. Symptomatic improvement occurred gradually in association with reduction of the outflow tract obstruction. The patient is in New York Heart Association class I-II 12 months after the operation. The rationale, methods, and management of this patient are discussed, as well as the potential for application of this operation in similar settings.

Although blood cardioplegia provides excellent protection, myocardial metabolic recovery is delayed. To evaluate the benefits of a terminal warm cardioplegic infusion after cold blood cardioplegia, we performed a prospective randomized trial in 20 patients undergoing elective coronary bypass grafting. Eleven patients received cold blood cardioplegia and nine patients received cold blood cardioplegia and warm blood cardioplegia before cross-clamp removal (hot shot). The hot shot provided oxygen and removed excess lactate from the arrested heart. After the hot shot lactate was extracted by the heart and tissue adenosine triphosphate and glycogen concentrations were preserved. Atrial pacing and volume loading 3 and 4 hours postoperatively decreased myocardial lactate extraction after cold blood cardioplegia but increased lactate extraction after the hot shot. Left atrial pressures were higher at similar end-diastolic volumes (by nuclear ventriculography), which suggested decreased diastolic compliance after cold blood cardioplegia. Terminal warm blood cardioplegia accelerated myocardial metabolic recovery, preserved high-energy phosphates, improved the metabolic response to postoperative hemodynamic stresses, and reduced left atrial pressures.

Hypertension following aorta-coronary bypass operations can contribute to myocardial ischemia. Nitroprusside therapy will reduce afterload, preload, and coronary perfusion pressure. Since both hypertension and its treatment can result in ischemic injury, nitroprusside must be carefully titrated to optimize cardiac function and metabolism. Thirty-one patients undergoing elective coronary bypass grafting were studied during a hypertensive episode (mean arterial pressure [MAP] = 119 +/- 18 mm Hg) and during nitroprusside therapy at an MAP of 97 +/- 11 mm Hg and at an MAP of 80 +/- 11 mm Hg (normotension). Nitroprusside also produced a significant (p less than 0.05) decrease in left atrial pressure (LAP), left ventricular end-diastolic volume index (EDVI) (stroke index divided by ejection fraction by nuclear angiography), stroke index, and stroke work index (SWI). Cardiac lactate extraction (LEx) and the ratio LEx/SWI increased (p less than 0.05) with the initial nitroprusside therapy, but lactate production resulted when the MAP was lowered to 80 mm Hg. Volume loading studies were performed during hypertension in four patients and during nitroprusside therapy in 15 patients. Neither performance nor compliance was significantly altered at an MAP of 97 mm Hg, but compliance decreased at normotension. Both hypertension and its treatment can result in inadequate myocardial metabolism. Nitroprusside should be titrated to maintain MAP between 90 and 100 mm Hg.

Although experimental studies suggest that blood cardioplegia provides better protection than crystalloid cardioplegia, clinical studies have been inconclusive. Ninety patients undergoing coronary bypass grafting were randomized to receive either blood (n = 43) or crystalloid cardioplegia (n = 47). The incidence of perioperative myocardial infarction was lower with blood cardioplegia (blood, n = 0; crystalloid, n = 5; p = 0.06), and the maximum MB isoenzyme of creatine kinase was significantly less with blood cardioplegia (blood, 26.3 +/- 12.6 U/L; crystalloid, 35.6 +/- 17.0 U/L, mean +/- standard deviation; p less than 0.02.) Sixty patients (blood cardioplegia, n = 28; crystalloid cardioplegia, n = 32) had more sensitive measurements to assess the metabolic response to aortic occlusion and to compare the metabolic and functional recovery from the operation. Coronary sinus blood flow (by the continuous thermodilution technique) was significantly lower after cross-clamp removal with blood cardioplegia (blood, 160 +/- 100 ml/min; crystalloid, 220 +/- 120 ml/min; p less than 0.05), indicating less reactive hyperemia. The cardiac production of lactate was significantly less with blood cardioplegia during aortic occlusion (blood, -0.5 +/- 0.9 mmol/L; crystalloid, -0.9 +/- 0.9 mmol/L; p less than 0.05) and immediately after aortic declamping (blood, -0.2 +/- 0.4 mmol/L; crystalloid, -0.7 +/- 0.7 mmol/L; p less than 0.01). Thermodilution cardiac output measurements permitted calculation of the left ventricular stroke work index, and nuclear ventriculograms permitted calculation of the left ventricular end-diastolic volume index and end-systolic volume index. Myocardial performance, systolic elastance, and diastolic compliance were determined from volume loading studies (250 to 500 ml colloid) performed 2 to 4 hours postoperatively. Myocardial performance (the left ventricular stroke work index-left ventricular end-diastolic volume index relation) and systolic elastance (the systolic blood pressure-left ventricular end-systolic volume index relation) were significantly better with blood cardioplegia (p less than 0.01 by multivariate analysis); diastolic compliance (the left atrial pressure-left ventricular end-diastolic volume index relation) was similar. Blood cardioplegia reduced ischemic injury, decreased anaerobic metabolism during arrest, and permitted better functional recovery. Blood cardioplegia provides superior protection for elective coronary bypass grafting and may improve the clinical results in patients with unstable angina and in other high-risk patients.

Blood conservation has been most successful when blood salvage techniques have been combined with postoperative normovolemic hemodilution. The hemodynamic and myocardial metabolic responses to normovolemic hemodilution were assessed in a prospective randomized trial. Twenty-seven patients were randomized to receive either blood and colloid solutions (colloid group, 13 patients) or crystalloid fluids (crystalloid group, 14 patients) following elective coronary revascularization. Although seven patients in the crystalloid group received blood products when the hemoglobin level fell below 7 gm/dl, blood bank requirements were less in the crystalloid group (colloid, 3.6 +/- 1.2 L; crystalloid, 1.5 +/- 1.0 L, p less than 0.01). The crystalloid group received twice as much fluid to maintain normovolemia (left atrial pressure between 8 and 10 mm Hg) in the first 72 hours postoperatively (colloid, 6.5 +/- 1.9 L; crystalloid, 14.5 +/- 3.1 L, p less than 0.01). The infusion of large volumes of crystalloid fluids resulted in a progressive postoperative anemia (hemoglobin: colloid, 12.1 +/- 1.6 gm/dl, crystalloid 8.9 +/- 1.7 gm/dl, p less than 0.01, 20 hours postoperatively). Although the crystalloid-treated patients had peripheral edema, pulmonary edema could not be documented and there was no difference in the physiological shunt fractions between the two groups. Preload (left atrial pressure), afterload (mean arterial pressure), and cardiac index were similar in the two groups. The crystalloid group had a delayed recovery of myocardial oxygen and lactate extraction postoperatively. Volume loading and atrial pacing 3 to 5 hours postoperatively maintained myocardial lactate extraction in the colloid group but decreased myocardial lactate extraction to ischemic levels in the crystalloid group. The use of crystalloid rather than colloid fluids in the early postoperative period conserved blood products but resulted in postoperative anemia and was associated with a delay in myocardial metabolic recovery. Normovolemic hemodilution should be employed with caution in patients who are at risk of perioperative ischemic injury.

Right coronary artery stenoses limit cardioplegic delivery to the right ventricle and may contribute to postoperative right ventricular dysfunction. Right ventricular function was evaluated in 39 patients with right coronary artery stenoses following elective coronary bypass operations. Hemodynamic and nuclear ventriculographic measurements, made between 3 and 6 hours postoperatively, revealed a progressive increase in pulmonary arterial pressure, pulse rate, and right ventricular ejection fraction (p less than 0.05). Right ventricular end-diastolic volume index (calculated from the thermodilution stroke index divided by the nuclear ejection fraction) decreased, but right atrial pressure increased (suggesting a decrease in compliance). The response to the infusion of 2 units of plasma (volume loading) was evaluated 3 hours postoperatively (EARLY) and again 5 hours postoperatively (LATE) in 21 patients. Right ventricular performance (the relation between cardiac index or right ventricular stroke work index and right ventricular end-diastolic volume index) and right ventricular systolic function (the relation between systolic pulmonary arterial pressure and right ventricular end-systolic volume index) were depressed EARLY and improved LATE (p less than 0.01 in analysis of covariance). Left ventricular performance (the relation between cardiac index or left ventricular stroke work index and left ventricular end-diastolic volume index) and left ventricular systolic function (the relation between systolic blood pressure and left ventricular end-systolic volume index) were similar EARLY and LATE. Right ventricular diastolic function (the relation between right atrial pressure and right ventricular end-diastolic volume index) and left ventricular diastolic function (the relation between left atrial pressure and left ventricular end-diastolic volume index) were significantly greater LATE than EARLY. Right, but not left, ventricular performance and systolic function were transiently depressed, and right and left ventricular diastolic stiffness were transiently decreased in the EARLY postoperative period. In patients with right coronary artery stenoses, current methods of cardioplegia may inadequately protect the right ventricle, but further studies are required to establish the relation between intraoperative protection and postoperative function.

Cardiac surgery stimulates the systemic synthesis of prostacyclin and thromboxane A2, but the cardiac release of these prostanoids has been reported infrequently. Fifty-four patients undergoing elective coronary artery bypass had coronary sinus catheters inserted to evaluate the cardiac release of the stable metabolites of prostacyclin (6-keto-prostaglandin F1 alpha) and thromboxane A2 (thromboxane B2). Arterial concentrations of 6-keto-prostaglandin F1 alpha and thromboxane B2 were elevated after cardiac cannulation and during cardiopulmonary bypass. The cardiac release of 6-keto-prostaglandin F1 alpha was observed after cannulation and during, but not after, cardiopulmonary bypass. Cardiac thromboxane B2 release was detected after cross-clamp release and persisted during the early postoperative period when cardiac 6-keto-prostaglandin F1 alpha release was no longer detectable. Cardiopulmonary bypass stimulated the systemic production of thromboxane and prostacyclin. The cardiac release of thromboxane was unopposed by cardiac prostacyclin production in the early postoperative period and may contribute to reperfusion injury.

Although the results of contemporary aortic valve replacement are excellent, cardiac surgeons must identify the factors that predict postoperative morbidity and mortality to develop alternative strategies for high-risk patients. Two hundred seventy-seven consecutive patients undergoing isolated aortic valve replacement between 1982 and 1984 were evaluated. Thirty-seven clinical and 13 preoperative hemodynamic variables were analyzed by univariate and multivariate statistics to determine the risk factors for postoperative morbidity and mortality. The operative mortality was 3%, the incidence of a postoperative low output syndrome was 12%, and the incidence of a perioperative myocardial infarction was 5%. A multivariate, logistic regression analysis found that age was the only the only independent predictor of mortality. Three factors independently predicted postoperative low output syndrome: age, the presence of coronary artery disease, and the peak systolic gradient in patients with aortic stenosis. Patients with aortic stenosis had a higher incidence of postoperative ventricular dysfunction (17%) than those with mixed valvular disease (9%) or aortic regurgitation (5%). Perioperative myocardial infarction was predicted by the extent of coronary artery disease. The incidence of perioperative myocardial infarction was higher in patients with triple-vessel coronary artery disease (13%) and those with left main stenosis (18%) than in patients with single- or double-vessel disease (4%) or those without coronary artery disease (4%). Because of the higher risk of aortic valve replacement in older patients, the risk-benefit ratio of the operation must be carefully assessed in the elderly. Improved methods of myocardial protection may reduce the risks for patients with aortic stenosis and symptomatic triple-vessel coronary artery disease.

Transient alterations in myocardial metabolism and ventricular function were observed after elective coronary bypass grafting despite apparently adequate intraoperative protection with cold potassium cardioplegia. Ninety patients had serial hemodynamic measurements and coronary sinus catheters inserted. Thirty-three patients had thermodilution coronary sinus flow catheters inserted to measure coronary sinus blood flow and to evaluate the myocardial utilization of oxygen and lactate. Nuclear ventriculograms were performed in 43 patients to assess ventricular function. Cardiac index fell after discontinuation of cardiopulmonary bypass and then rose between 2 and 24 hours postoperatively. Myocardial oxygen consumption steadily increased during this period. Myocardial lactate production reverted to lactate extraction 30 minutes after reperfusion. Reactive hyperemia was present during the first 10 minutes after cross-clamp release, and coronary sinus blood flow increased gradually during the first 24 hours postoperatively. The response to the stress of volume loading (the infusion of 250 to 500 ml of a colloid solution) and atrial pacing (at a rate of 110 beats/min) was evaluated 2 to 4 hours postoperatively (EARLY) and between 4 to 6 hours postoperatively (LATE). Volume loading resulted in a decrease in lactate extraction EARLY and an increase LATE (EARLY: -0.07 +/- 0.35 mmol/L; LATE: 0.08 +/- 0.32 mmol/L, mean +/- standard deviation not significant). Atrial pacing resulted in a decrease in lactate extraction EARLY and an increase LATE (EARLY: -0.11 +/- 0.34 mmol/L; LATE: 0.14 +/- 0.36 mmol/L, p less than 0.05). Diastolic compliance (the relation between the end-diastolic volume index) decreased between EARLY and LATE. Systolic function (the relation between the systolic blood pressure and the end-systolic volume index) and myocardial performance (the relation between the left ventricular stroke work index and the end-diastolic volume index) were unchanged. Ejection fraction correlated inversely with the end-diastolic volume index and did not represent an independent index of contractility. After elective coronary bypass grafting and cold crystalloid cardioplegia, myocardial metabolism recovered slowly. Hemodynamic stresses should be avoided in the early postoperative period to prevent progressive ischemic injury.

Calcium channel blockers may prevent myocardial injury during cardioplegia and reperfusion. A prospective, randomized trial was instituted to evaluate the hemodynamic and myocardial metabolic recovery in 40 patients undergoing elective aorta-coronary bypass with either diltiazem in crystalloid potassium cardioplegia (n = 20) or crystalloid potassium cardioplegia (n = 20). In a preliminary trial, doses between 150 and 250 micrograms/kg reduced the period of heart block after cross-clamp removal (90 +/- 110 minutes) from that found with higher doses and improved myocardial metabolism. In the randomized trial, diltiazem cardioplegia (150 micrograms/kg) produced coronary vasodilatation during cardioplegia and produced less reactive hyperemia during reperfusion. Myocardial oxygen extraction was lower and myocardial lactate production was less after diltiazem cardioplegia during reperfusion. Tissue adenosine triphosphate and creatine phosphate concentrations were preserved better after diltiazem cardioplegia. The postoperative creatine kinase MB levels were less (p less than 0.05) after diltiazem cardioplegia, which indicated less myocardial injury. Postoperative volume loading demonstrated that systolic function (the relation between systolic blood pressure and end-systolic volume index) was depressed after diltiazem cardioplegia compared to crystalloid cardioplegia, but cardiac index was higher because afterload (mean arterial pressure) was lower and preload (end-diastolic volume index) was higher. Diltiazem cardioplegia preserved high-energy phosphates, improved postoperative myocardial metabolism, and reduced ischemic injury after elective coronary bypass. However, diltiazem was a potent negative inotrope and produced prolonged periods of electromechanical arrest. Diltiazem cardioplegia may be of value in patients with severe ischemia but should be used with caution in patients with ventricular dysfunction, and a dose-response relation must be established at each institution before clinical use.